Description:TECHNICAL FIELD
[0001] The present disclosure relates to ethanol production plants. More specifically, the present disclosure pertains to an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content.

BACKGROUND
[0002] Ethanol production from renewable biomass has gained attention as an environmentally friendly alternative to fossil fuels. Among the various feedstocks, lignocellulosic biomass is considered a promising source for bioethanol. Lignocellulosic biomass is composed of cellulose, hemicellulose, and lignin. Lignin, a complex, non-sugar polymer in plant cell walls, provides structural support, rigidity, and resistance to degradation. However, lignin cannot be directly used for ethanol production through microbial fermentation, as it is highly resistant to breakdown by most enzymes and microbes. This resistance presents a significant challenge in bioethanol production, as lignin inhibits microbial growth and fermentation, thus reducing the overall efficiency and economic viability of the process. Although lignin cannot be converted into ethanol, it has value as an energy source. When burned, lignin generates significant heat, making it an excellent feedstock for combined heat and power (CHP) systems. In a bio-refinery, lignin can be utilized in a sustainable and eco-friendly manner to produce energy, improving the efficiency and economic viability of biofuel production. Therefore, while lignin poses a challenge for ethanol production, its energy potential is an important asset in bio-refinery systems.
[0003] The main difficulty in producing bioethanol from lignocellulosic biomass lies in efficiently converting cellulose and hemicellulose into fermentable sugars while managing the effects of lignin. Traditional pre-treatment methods, such as chemical, physical, and biological processes, are used to break down lignin and make cellulose and hemicellulose more accessible. However, these methods often require high energy input, generate by-products, and involve costly chemicals.
[0004] Additionally, the variability in lignin content among different biomass types adds complexity to the process. Biomass with higher lignin content is especially challenging, requiring more intensive and expensive pre-treatment. Biomass with high lignin content presents a unique challenge in optimizing conversion to maximize ethanol yield while minimizing costs and maximizing efficiency. Existing processes for ethanol production from biomass are not fully optimized for high-lignin slurries, which require specialized treatments due to the significant impact lignin has on energy input.
[0005] Current production equipment is often designed for lower lignin content, limiting its ability to effectively utilize high-lignin biomass, which hampers efficiency and cost-effectiveness for large-scale commercial production. Lignin-rich stillage, if not properly managed, can accumulate on the components of a distillation tower, particularly on the sieve trays where fractionation occurs. These trays are essential for vapour-liquid interaction and mass transfer, enabling separation based on boiling points. The accumulation of lignin sludge obstructs the flow of liquids, reducing the efficiency of the sieve trays by hindering mass transfer. This disrupts the distillation process, lowering the quality of the product and overall tower performance. Traditional methods for managing lignin accumulation often involve labour-intensive cleaning or periodic shutdowns for maintenance. These processes can be disruptive, leading to unscheduled downtimes that halt production, resulting in economic losses due to reduced throughput and the cost of cleaning labour and resources. Frequent maintenance can also decrease long-term operational efficiency, raising costs and reducing profitability. Therefore, an effective and continuous solution for managing lignin-rich stillage is essential to maintain smooth operations, improve distillation efficiency, and reduce the economic impact of maintenance.
[0006] Given these challenges, there is a need for more efficient methods for producing ethanol from biomass slurries with high or very high lignin content. The current invention addresses these issues by providing an apparatus and method that optimize distillation and separation of ethanol broth, offering a more cost-effective, sustainable solution for bioethanol production. The system also enables scalability, improving the economic viability and sustainability of biofuels as a renewable energy source.

OBJECTS OF THE PRESENT DISCLOSURE
[0007] An object of the present disclosure is to provide an apparatus designed to efficiently process biomass slurries, particularly those with high lignin content, to achieve high ethanol yields in distillation columns.
[0008] Another object of the present disclosure is to reduce operational costs in bioethanol production by reducing energy consumption, and chemical usage. This makes the apparatus and method economically competitive for large-scale commercial ethanol production. This is to provide an environmentally sustainable solution for bioethanol production by minimizing the need for harsh chemicals, reducing energy consumption, and minimizing the generation of by-products. This also improves the sustainability of biofuels as a renewable energy source.
[0009] Another object of the present disclosure is to provide a flexible apparatus that can accommodate various biomass feedstocks with high lignin content, making it scalable and versatile for different industrial applications. This is to enhance the scalability and efficiency of bioethanol production, ensuring that the apparatus can be easily scaled up for large-scale production while maintaining high efficiency and low operational costs. This scalability supports the growing global demand for biofuels.

SUMMARY
[0010] Aspects of the present disclosure relate to an apparatus and a method for producing ethanol from biomass slurries, particularly those with high or very high lignin content. The apparatus and method are designed to handle biomass slurries and ethanol broth by addressing the challenges posed by lignin, a complex polymer. The system allows for effective pre-treatment of biomass slurries with high lignin content without the need for excessive energy, harsh chemicals, or complex procedures.
[0011] In an aspect, the present disclosure discloses an apparatus for producing ethanol with a biomass slurry and/or ethanol broth having high lignin content. The apparatus includes a distillation unit configured to receive and process the biomass slurry and ethanol broth to reduce lignin content thereof. The distillation unit includes a heat exchanger/reboiler configured to boil a liquid at a bottom of the distillation unit to generate vapour traversing in a vertically upward direction within the distillation unit. The distillation unit also includes at least one sieve tray having a plurality of perforations to enable passage for the vapour to pass therethrough, and a first set of spray nozzles configured to spray a first cleaning mixture over the at least one sieve tray to prevent clogging of lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray.
[0012] The distillation unit includes at least one feed tray positioned downstream of the at least one sieve tray. The at least one feed tray includes a plurality of pall rings to segregate lignin sludge from the biomass slurry and ethanol broth, and a second set of spray nozzles configured to spray a second cleaning mixture over the at least one feed tray to prevent clogging of the lignin sludge present in the biomass slurry and ethanol broth received by the at least one feed tray, and enable collection of the lignin sludge into a sump of the at least one feed tray. The at least one feed tray also includes a plurality of risers configured to allow the vapour generated by the heat exchanger/reboiler to escape therethrough in the vertically upward direction.
[0013] The distillation unit also includes a feed inlet device configured to receive and supply the biomass slurry and ethanol broth to any of the at least one sieve tray and the at least one feed tray. The feed inlet device includes a plurality of corrugated blades coupled to a shaft accommodated within a casing. The plurality of corrugated blades are configured to rotate about a rotational axis of the shaft upon supply of the biomass slurry and ethanol broth into the casing. The feed inlet device also includes a plurality of protrusions/upward notches positioned at a bottom of the casing in a staggered manner to disrupt flow of the lignin sludge and enable collection of the lignin sludge into a downcomer of the feed inlet device.
[0014] According to an embodiment, the first set of spray nozzles may be timer-controlled to dispense the first cleaning mixture over the at least one sieve tray in pre-defined time intervals.
[0015] According to an embodiment, the second set of spray nozzles may be timer-controlled to dispense the second cleaning mixture over the at least one feed tray in pre-defined time intervals.
[0016] According to an embodiment, the distillation unit may include a controller configured to monitor clogging of the lignin sludge received by any of the at least one sieve tray and the at least one feed tray. The controller may be configured to monitor accumulation of the biomass slurry and ethanol broth on the plurality of corrugated blades of the feed inlet device. The controller may also be configured to control actuation of the first set of spray nozzles, the second set of spray nozzles and one or more washing nozzles configured within the casing of the feed inlet device based on pre-determined washing cycles, and one or more parameters pertaining to purity of the ethanol to be produced.
[0017] According to an embodiment, the first cleaning mixture may include equimolar mixture of acetic acid and methanol. According to another embodiment, the second cleaning mixture may include non-equimolar mixture of acetic acid and methanol.
[0018] According to an embodiment, the apparatus may include a ratio controller configured to control the equimolar mixture of methanol and acetic acid in a ratio of about 3% to 6% by volume.
[0019] According to an embodiment, the biomass slurry and ethanol broth may contain about 25-30% weight/weight (w/w) lignin sludge. According to another embodiment, the biomass slurry and ethanol broth may contain about 20-25% w/w lignin sludge.
[0020] According to an embodiment, the at least one sieve tray and the at least one feed tray may be arranged in a staggered manner relative to one another along a height of the distillation unit.
[0021] According to an embodiment, each corrugated blade of the plurality of corrugated blades may have a proximal end coupled to the shaft and a distal end extending into the casing in a radial direction of the shaft. A height of the corrugated blade at the distal end may be smaller than the height of corrugated blade at the proximal end.
[0022] According to an embodiment, the corrugated blade may have a curved profile extending from the proximal end to the distal end. The height of the corrugated blade may decrease drastically at an intermediate position between the proximal end and the distal end.
[0023] According to an embodiment, the feed inlet device may include a feed entry region accommodating the plurality of corrugated blades, and having a feed entry nozzle for receiving the biomass slurry and ethanol broth at a pre-defined rate. The feed inlet device may also include a washing region accommodating the one or more washing nozzles configured within the casing of the feed inlet device. The washing region may be adapted to receive and circulate a washing liquid, through the one or more washing nozzles, for cleaning accumulated biomass slurry and ethanol broth from the plurality of corrugated blades.
[0024] According to an embodiment, the at least one sieve tray may include a plurality of protrusions/upward notches formed in a staggered configuration over an upper surface thereof to disrupt flow and prevent clogging of the lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray. Each of the plurality of protrusions/upward notches may have a triangular-shaped profile.
[0025] According to an embodiment, the distillation unit may include one or more settling tanks configured to receive the lignin sludge collected in the sump of the at least one feed tray.
[0026] According to an embodiment, the distillation unit may include a centrifuge configured to separate residual sludge from the lignin sludge received by the one or more settling tanks. A liquid output from the centrifuge may be supplied to the heat exchanger/reboiler to generate the vapour.
[0027] According to an embodiment, the at least one feed tray may include a drain outlet pipe positioned at the sump to facilitate removal of the collected lignin sludge. The drain outlet pipe may be controlled by a valve synchronized with the second set of spray nozzles to optimize transfer of the collected lignin sludge to the one or more settling tanks.
[0028] According to an embodiment, the distillation unit may include an outlet nozzle configured to extract purified ethanol from the biomass slurry and ethanol broth.
[0029] According to an embodiment, the plurality of pall rings may be arranged on the at least one feed tray in a random packing arrangement to facilitate collection of the lignin sludge into the sump.
[0030] According to an embodiment, the at least one feed tray may include a first feed tray having an arrangement of the plurality of pall rings, the second set of spray nozzles and the plurality of risers in a first configuration, and a second feed tray having an arrangement of the plurality of pall rings, the second set of spray nozzles and the plurality of risers in a second configuration different from the first configuration. The first feed tray and the second feed tray may be arranged in a staggered manner relative to one another along the height of the distillation unit.
[0031] According to an embodiment, the at least one sieve tray may include a first weir/downcomer to enable supply of the biomass slurry and ethanol broth in a downstream direction only when the biomass slurry and ethanol broth overflows through the first weir/downcomer.
[0032] According to an embodiment, the at least one feed tray may include a second weir/downcomer to allow supply of the biomass slurry and ethanol broth in the downstream direction only when the biomass slurry and ethanol broth overflows through the second weir/downcomer.
[0033] According to another aspect of the present disclosure, a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content is disclosed. The method includes receiving, by a feed inlet device of a distillation unit, the biomass slurry and ethanol broth at a pre-defined rate. The method includes boiling, by a heat exchanger/reboiler, a liquid at a bottom of the distillation unit to generate vapour traversing in a vertically upward direction within the distillation unit. The method includes segregating, by rotation of a plurality of corrugated blades of the feed inlet device, lignin sludge present in the biomass slurry and ethanol broth. The method also includes supplying, by the feed inlet device, the biomass slurry and ethanol broth to at least one sieve tray having a plurality of perforations to enable passage for the vapour to pass therethrough, and segregating, by a plurality of pall rings of at least one feed tray positioned downstream of the at least one sieve tray, lignin sludge from the biomass slurry and ethanol broth. Thereafter, the method include a step of allowing, by a plurality of risers of the at least one feed tray, the vapour generated by the heat exchanger/reboiler to escape therethrough in the vertically upward direction.
[0034] The method further includes regulating, by a controller, actuation of one or more washing nozzles configured within the casing of the feed inlet device to circulate a washing liquid for cleaning accumulated biomass slurry and ethanol broth from the plurality of corrugated blades, actuation of a first set of spray nozzles to control dispensing of a first cleaning mixture over the at least one sieve tray to prevent clogging of the biomass slurry and ethanol broth received by the at least one sieve tray, actuation of a second set of spray nozzles to control dispensing of a second cleaning mixture over the at least one feed tray to enable collection of the lignin sludge into a sump of the at least one feed tray.
[0035] According to an embodiment, the step of regulating may include controlling actuation of the one or more washing nozzles, the first set of spray nozzles and the second set of spray nozzles based on pre-determined washing cycles.
[0036] According to an embodiment, the biomass slurry and ethanol broth may contain about 25-30% w/w lignin sludge. According to another embodiment, the biomass slurry and ethanol broth may contain about 20-25% w/w lignin sludge.
[0037] According to an embodiment, the method may include supplying the lignin sludge collected in the sump to one or more settling tanks, and separating, by a centrifuge of the distillation unit, residual sludge from the lignin sludge received by the one or more settling tanks. The method may further include supplying a liquid output from the centrifuge to the heat exchanger/reboiler to generate the vapour.
[0038] According to an embodiment, the method may include extracting, by an outlet nozzle of the distillation unit, purified ethanol from the biomass slurry and ethanol broth.
[0039] According to an embodiment, the method may also include monitoring, by a controller, clogging of the lignin sludge received by any of the at least one sieve tray and the at least one feed tray. The method may include monitoring, by the controller, accumulation of the biomass slurry and ethanol broth on the plurality of corrugated blades of the feed inlet device. The method may further include controlling, by the controller, actuation of the first set of spray nozzles and the second set of spray nozzles based on pre-determined washing cycles and one or more parameters pertaining to purity of the ethanol to be produced.
[0040] According to an embodiment, the method may include regulating, by a first weir/downcomer of the at least one sieve tray, flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in a downstream direction only when the biomass slurry and ethanol broth overflows through the first weir/downcomer. The method may further include regulating, by a second weir/downcomer of the at least one feed tray, flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in the downstream direction only when the biomass slurry and ethanol broth overflows through the second weir/downcomer.
[0041] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0043] FIG. 1 illustrates an exemplary schematic representation of an apparatus for producing ethanol with a biomass slurry and ethanol broth having high or very high lignin content, in accordance with an embodiment of the present disclosure;
[0044] FIG. 2 shows an exemplary representation of an arrangement of multiple feed trays and the feed inlet device along a height of a distillation unit of the apparatus, in accordance with an embodiment of the present disclosure;
[0045] FIG. 3A illustrates an exemplary plan view of a plurality of corrugated blades of the feed inlet device, in accordance with an embodiment of the present disclosure;
[0046] FIG. 3B illustrates an exemplary representation of a casing of the feed inlet device, in accordance with an embodiment of the present disclosure; and
[0047] FIG. 4 illustrates an exemplary flow chart representation of a method for producing ethanol with a biomass slurry and ethanol broth having high or very high lignin content, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0048] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosures as defined by the appended claims.
[0049] The present invention addresses various engineering challenges associated with distillation columns used for bio-ethanol distillation, particularly when processing feedstock with high or very high lignin content. Along with ethanol, side products such as acetic acid, fusel oil, and technical oil are produced in the distillation column. The quality of the ethanol meets the Indian standards (IS 15464:2004) for anhydrous ethanol, which is suitable for automotive fuel, with a minimum ethanol content of 99.50% by volume at 15.6°C, a relative density not exceeding 0.7961, and a flashpoint of 16.6°C. Due to the azeotropic mixture formed by ethanol and water at around 91% ethanol mole concentration (~96% by volume), further purification by distillation is hindered. Molecular membranes are employed to achieve the required high-purity ethanol for blending purposes.
[0050] The ethanol production process generally includes pre-treatment of biomass, followed by enzymatic hydrolysis of lignocellulosic biomass to release fermentable sugars (C-5 and C-6 sugars), which are then fermented by yeast to produce ethanol. The resulting ethanol broth is distilled in a column that contains micro-lignin from the steam explosion during the pre-treatment, dead yeast, enzymatic biomass, water, unutilized nutrients, and unconverted cellulose and hemicellulose. According to the Petroleum Planning & Analysis Cell (PPAC), with 20% ethanol blending in gasoline, 11,178 million liters of ethanol are needed in the country. This growing demand for bio-ethanol is expected to drive the need for novel distillation systems in bio-ethanol plants. Due to the presence of micro-lignin in the ethanol broth, the valves and sieve trays in the distillation column are prone to frequent clogging, requiring rapid and efficient cleaning for each tray. The cleaning cycle depends on the type of biomass used, although the process remains adaptable to different feedstocks. The lignin content of the biomass influences the cleaning cycle time.
[0051] Embodiments described herein provide a novel distillation column/tower for cellulosic or 2G ethanol bio-refinery with high or very-high lignin biomass feed. The distillation tower is capable of robust bio-ethanol distillation from feedstocks such as sugarcane bagasse and jute extracts. The distillation tower is also applicable in oil and gas refineries and bio-refineries, offering an innovative solution for distilling feedstock with high lignin content in the oil and gas sector. The distillation tower focuses on reducing the environmental footprint globally, addressing the challenges and benefits of three-phase distillation in bio-ethanol production.
[0052] The present disclosure provides an apparatus and method for effectively processing biomass slurries with high or very high lignin content, aiming to achieve high ethanol yields. This results in a cost-effective and environmentally sustainable ethanol production process, lowering operational costs, energy consumption, and the generation of by-products. The apparatus is versatile and can accommodate various biomass feedstocks, making it scalable for large-scale commercial bioethanol production, thus supporting the sustainability of biofuels as a renewable energy source.
[0053] FIG. 1 shows an exemplary schematic representation of an apparatus 100 designed for the production of ethanol from a biomass slurry and ethanol broth with high or very high lignin content. The apparatus 100 incorporates a distillation unit (also interchangeably referred to as a “distillation tower” herein) 102, which is specifically engineered to receive and process the biomass slurry and ethanol broth to reduce its lignin content. The biomass slurry and/or ethanol broth that can be efficiently processed by the distillation tower 102 may include various waste materials, including Cassava solid waste, paper and pulp waste, fish processing waste, jute extracts, sawdust, lumbering and forestry waste, and acre nut waste. These materials typically contain around 25-30% lignin by weight (w/w). In certain embodiments, the biomass slurry and ethanol broth may include sugarcane bagasse and jute extracts, which generally contain approximately 20-25% lignin by weight (w/w).
[0054] The distillation unit 102 plays a crucial role in processing these lignin-rich slurries, as lignin is a challenging component in biomass for ethanol production. This lignin content tends to interfere with the breakdown of cellulose and hemicellulose into fermentable sugars, which is an essential step in ethanol production. By reducing the lignin content, the apparatus 100 makes the biomass more accessible for enzymatic hydrolysis and fermentation, thus improving the overall efficiency of the ethanol production process. The variety of biomass feedstocks that the apparatus 100 can handle demonstrates its flexibility, making it adaptable for large-scale applications in bioethanol production.
[0055] The distillation tower 102 includes a feed inlet device 104 that receives the biomass slurry and ethanol broth containing the high lignin-laden ethanol broth. The feed inlet device 104 may be turbine-type feed inlet device that efficiently minimizes biomass entrainment, ensures segregation of lignin content from the biomass, and optimizes the overall distillation performance. The distillation tower 102 includes a heat exchanger 106, such as a reboiler, configured to boil a liquid at a bottom of the distillation tower 102 to generate vapour traversing in a vertically upward direction within the distillation tower 102. The distillation tower 102 also includes one or more sieve trays 108-1, 108-2, 108-3, … 108-N (also referred to as “sieve tray 108” herein) arranged along a height of the distillation tower 102. The sieve tray 108 includes a plurality of perforations 110 to enable passage for the vapour generated by the heat exchanger/reboiler 106 to pass therethrough, and a first set of spray nozzles 112 configured to spray a first cleaning mixture over the sieve tray 108 to prevent clogging of lignin sludge present in the biomass slurry and ethanol broth received by the sieve tray 108. The first set of spray nozzles 112 may be timer-controlled to dispense the first cleaning mixture over the at least one sieve tray in pre-defined time intervals of 5 to 25 minutes, for example. Each sieve tray 108 may include 1 to 20 spray nozzles 112 to direct the first cleaning mixture in an opposite direction to fractionation flow of the biomass slurry and ethanol broth over the sieve tray 108. The first cleaning mixture may include equimolar mixture of acetic acid and methanol. The sieve tray 108 may include a first weir to allow supply of the biomass slurry and ethanol broth in a downstream direction only when the biomass slurry and ethanol broth overflows through the first weir.
[0056] The distillation tower 102 also includes one or more feed trays 114-1, 114-2, … 114-N (also referred to as “feed tray 114” herein) arranged along the height of the distillation tower 102. At least one feed tray 114 may be positioned downstream of at least one sieve tray 108 such that the biomass slurry and ethanol broth flows over the feed tray 114 after passing through the sieve tray 108 located upstream of the feed tray 114. The feed trays 114 may be formed of SS-316 (Stainless Steel) to efficiently facilitate processing of corrosive and abrasive C-5 sugar (xylan) and C-6 sugar (glucose) laden biomass slurry and ethanol broth.
[0057] The distillation tower 102, as depicted in FIG. 1, is designed with several key features to facilitate efficient distillation and ethanol recovery. A liquid inlet nozzle 116 is configured to introduce the liquid feed into the distillation tower 102, directing it to the reboiler 106. The reboiler 106 heats the liquid supplied into the distillation tower 102 through the liquid inlet nozzle 116, to generate the vapour that ascends vertically within the distillation tower 102. This vapour is crucial for the distillation/separation process for production of high yield of ethanol from the biomass slurry and ethanol broth. As the vapour rises through the distillation tower 102, it allows for the separation of various components of the biomass slurry and ethanol broth based on their boiling points to facilitate production of ethanol with improved purity.
[0058] The distillation tower 102 may include a vapour outlet nozzle 118, which is designed to drain the vapour generated by the reboiler 106. This vapour is directed out of the distillation tower 102 and into the surrounding ambient environment, where it can undergo further processing, such as condensation or phase separation. Additionally, the distillation tower 102 may be equipped with a vapour inlet nozzle that facilitates entry of the vapour generated by the reboiler 106 into the distillation tower 102, helping maintain the necessary vapour-liquid equilibrium for effective separation. A liquid outlet nozzle positioned at the bottom of the distillation tower 102 allows the liquid from a liquid pool located at the bottom of the distillation tower 102 to flow into the reboiler 106, ensuring the liquid is constantly circulated and heated. This circulation is essential for the continued operation of the distillation process, as it ensures that the liquid is heated appropriately to produce further vapour for separation of ethanol from the biomass slurry and ethanol broth. The High Liquid Level (HLL) for the reboiler liquid pool at the bottom/base of the distillation tower 102 may be calibrated 10% higher than conventional distillation columns.
[0059] The distillation tower 102 may include an outlet nozzle 120, which enables extraction of the purified ethanol from the biomass slurry and ethanol broth. The outlet nozzle 120 serves as the key point for the collection of the ethanol product that has been separated during the distillation process. The distillation tower 102 is also configured with a methanol tank 122 and an acetic acid tank 124, both of which store by-products generated during the cleaning cycles for the sieve trays 108 and the feed trays 114. These by-products are obtained from side streams that flush cleaning mixtures over the sieve trays 108 and the feed trays 114, respectively. The methanol tank 122 stores methanol, and the acetic acid tank 124 stores acetic acid, both of which are recovered and stored for potential reuse or disposal. Each of these tanks 122 and 124 is equipped with a metering pump, which plays a critical role in ensuring that the correct amount of methanol and acetic acid is accurately delivered to the spray nozzles of the sieve trays 108 and the feed trays 114. This precise dosing is essential to maintain optimal cleaning cycles for the sieve trays 108 and feed trays 114, ensuring that any contaminants or residues are removed effectively. This cleaning process is crucial for maintaining consistent ethanol quality, as any build-up on the sieve trays 108 and the feed trays 114 could hinder proper separation and reduce product purity. In an exemplary embodiment, the metering pumps connected to the methanol and acetic acid tanks 122, 124 may be configured to pump an equimolar mixture of about 3% to 6% (by volume) methanol and acetic acid. The ratio of these two chemicals is carefully controlled by a ratio controller 126, which ensures that the cleaning mixtures used for cleaning the sieve trays 108 and the feed trays 114 are in the correct proportion for effective tray maintenance.
[0060] The distillation tower 102 may include a condenser 128, which plays a vital role in cooling and condensing the vapour exiting the vapour outlet nozzle 118. The condenser 128 helps convert the vapour back into a liquid phase, which can then be separated and collected for further processing. In conjunction with the condenser, a 3-Phase separator/reflux drum 130 is installed to efficiently separate and recover the different phases of the vapour, which includes condensed liquid, residual gases, and any non-condensable components. This phase separation is important for optimizing the distillation process and ensuring that the desired products are recovered efficiently. To ensure the quality and composition of the vapour stream before it is condensed, a product analyzer 128-1 is installed upstream of the condenser 128. The product analyzer 128-1 continuously monitors the composition of the vapour exiting the vapour outlet nozzle 118, providing real-time data on the quality of the vapour. This information is crucial for process control, as it ensures that the vapour meets the necessary specifications for condensation and further processing.
[0061] For handling heavier or more viscous liquids that may accumulate at the bottom of the distillation tower 102, a heavy product pump 132 is incorporated. The heavy product pump 132 is responsible for transferring these liquid products, which may be high in temperature or viscosity, from the bottom of the distillation tower 102 to downstream processing units or storage tanks. This ensures that the distillation process operates smoothly, even with challenging product characteristics. Additionally, a reflux pump 134 is employed to circulate a portion of the condensed vapour back into the distillation tower 102. The reflux pump 134 helps improve separation efficiency by sending the condensed liquid back to the distillation tower 102, where it can interact with the rising vapour. This refluxing action aids in refining the separation process, resulting in higher ethanol purity and overall performance of the distillation tower 102.
[0062] FIG. 2 illustrates an exemplary representation of an arrangement of multiple feed trays 114 and the feed inlet device 104 along the height of the distillation unit 102 of the apparatus 100. Each feed tray 114 includes a plurality of pall rings 202 to segregate lignin sludge from the biomass slurry and ethanol broth when the biomass slurry and ethanol broth passes over the feed tray 114. Each pall ring 202 may be formed as a hollow, cylindrical structure made from materials like metal, plastic, or ceramic. The pall ring 202 may include multiple openings or slots around its surface, which provide a large surface area for contact between the two phases, i.e., liquid and vapour, promoting efficient mass transfer and fluid flow. The pall rings 202 minimize the number of contours and crevices that cause flow of the biomass slurry and ethanol broth to be held up, and assist segregation of the lignin sludge present in the biomass slurry and ethanol broth.
[0063] The feed tray 114 also includes a second set of spray nozzles 204 configured to spray a second cleaning mixture over the feed tray 114 to prevent clogging of the lignin sludge present in the biomass slurry and ethanol broth received by the feed tray 114. The pall rings 202 ensure that the lignin sludge present in the biomass slurry and ethanol broth is stagnated and segregated from the biomass slurry and ethanol broth. Subsequently, the second set of spray nozzles 204 may dispense the second cleaning mixture over the feed tray 114 to enable collection of the stagnated lignin sludge into a sump 206 of the feed tray 114. Each feed tray 114 may also include a plurality of risers or chimneys 208 that allow the vapour generated by the heat exchanger/reboiler 106 to escape therethrough in the vertically upward direction, and facilitate liquid-gas interaction between the biomass slurry and ethanol broth and the vapour. The second set of spray nozzles 204 may be timer-controlled to dispense the second cleaning mixture over the feed tray 114 in pre-defined time intervals of 5 to 25 minutes, for example. In an exemplary embodiment, each feed tray 114 may include 1 to 20 spray nozzles 204 to direct the second cleaning mixture in the opposite direction to the fractionation flow of the biomass slurry and ethanol broth over the feed tray 114. The second cleaning mixture may contain an non-equimolar mixture of acetic acid and methanol.
[0064] The first and second sets of spray nozzles 112, 204 may be configured to flush the cleaning mixtures over the corresponding sieve tray 108 or the feed tray 114 in any of three primary directions, including co-current, counter-current, and cross-flow directions, each serving a unique function in the process of removing lignin agglomerates or nucleation sites on the sieve tray 108 or the feed tray 114 within the distillation tower 102.
[0065] The pall rings 202 may be arranged over the feed tray 114 in a staggered/random manner such that the lignin sludge contained within the biomass slurry and ethanol broth is segregated when the biomass slurry and ethanol broth passes over the feed tray 114, and gets collected within a sump 206 of the feed tray 114.
[0066] In an exemplary embodiment, the feed trays 114 may include at least first feed tray 114-1 having an arrangement of the pall rings 202, the second set of spray nozzles 204 and the chimneys 208 in a first configuration, a second feed tray 114-2 having an arrangement of the pall rings 202, the second set of spray nozzles 204 and the chimneys 208 in a second configuration different from the first configuration, and a third feed tray having an arrangement of the pall rings 202, the second set of spray nozzles 204 and the chimneys 208 in a third configuration that is different from the first and second configurations. The first and second trays 114-1 and 114-2 may be arranged in a staggered manner relative to one another along the height of the distillation tower 102, as depicted in FIG. 2.
[0067] The apparatus 100 may include the ratio controller 126 configured to control the equimolar mixture of methanol and acetic acid in a ratio of about 3% to 6% by volume, for each of the first cleaning mixture and the second cleaning mixture. The distillation tower 102 may include a controller configured to monitor clogging of the lignin sludge received by any of the sieve trays 108 and the feed trays 114. The controller may also be configured to control actuation of the first set of spray nozzles 112 and the second set of spray nozzles 204 based on pre-determined washing cycles, and one or more parameters pertaining to purity of the ethanol to be produced. The controller may also be configured to actuate the first and second sets of spray nozzles 112, 204 in response to ethanol specification disturbances caused by the clogging/choking of the sieve trays 108 and the feed trays 114.
[0068] In an exemplary embodiment, the controller is configured to manage the first and second sets of spray nozzles 112, 204 to eject the equimolar mixture of acetic acid and methanol. This equimolar mixture, when mixed with the pool liquid pool of the reboiler 106, plays a pivotal role in breaking down the nucleation sites of agglomerating lignin. Typically, C-5 sugar (xylan) and C-6 sugar (glucose) provide a crucial substrate for agglomeration and nucleation sites on suspended micro-lignin fibers, subsequently converting them into bulky lignin lumps near the sieves of the column tray. The 3%-6% (by volume) equimolar mixture of acetic acid and methanol helps prevent these nucleation sites from forming in the early stages of the distillation process.
[0069] The controller may be implemented using various hardware configurations or a combination of software and hardware features. For instance, the controller may incorporate microcontrollers, switches, relays, gates, and specialized hardware features like application-specific integrated circuits (ASICs), electrically erasable programmable read-only memories (EEPROMs), or field-programmable gate arrays (FPGAs). In some cases, memory components like non-volatile random access memory (RAM) or read-only memory (ROM) may also form part of the controller. In another embodiment, the controller may be entirely software-based, operating either as part of an operating system or as an application running on one. The controller may be connected to the first and second sets of spray nozzles 112, 204 either wirelessly or in a wired manner.
[0070] The sieve trays 108 and the feed trays 114 may be arranged in a staggered manner relative to one another along the height of the distillation tower 102, such that the biomass slurry and ethanol broth introduced within the distillation tower 102 by the feed inlet device 104 passes through each of the sieve trays 108 and the feed trays 114 to enable effective segregation of the lignin sludge from the biomass slurry and ethanol broth. In an exemplary embodiment, the feed inlet device 104 may be positioned such that the biomass slurry and ethanol broth introduced within the distillation tower 102 is supplied over any or a combination of the sieve trays 108 and the feed trays 114 in a sequential manner.
[0071] The distillation tower 102 may include one or more settling tanks including a primary settling tank 136 and a secondary settling tank 138 configured to receive the lignin sludge collected in the sumps 206 of each of the feed trays 114. The secondary settling tank 138 may be an alternate outlet route for collection of the first and second cleaning mixtures and the lignin sludge received from the sumps 206 of the feed trays 114. The distillation tower 102 may also include a centrifuge 140 configured to separate residual sludge from the lignin sludge received by the primary and secondary settling tanks 136, 138. A settling tank pump 142 may be configured to pump the collected fluid from the primary and secondary settling tanks 136, 138 to the centrifuge 140 to separate the residual lignin sludge from the collected fluid. A liquid output from the centrifuge 140 may be supplied to the reboiler 106, through a pump, to generate the vapour that traverses in the vertically upward direction within the distillation tower 102. The centrifuge 102 may include a drain outlet 140-1 to enable drainage of the liquid sludge.
[0072] Each of the feed trays 114 may include a drain outlet pipe 210, as shown in FIG. 2, positioned at the sump 206 to facilitate removal of the collected lignin sludge. The drain outlet pipe 210 may be controlled by a valve synchronized with the second set of spray nozzles 204 to optimize transfer of the collected lignin sludge to any of the primary and secondary settling tanks 136, 138. Each of the feed trays 114 may include a second weir 212 to allow supply of the biomass slurry and ethanol broth in the downstream direction only when the biomass slurry and ethanol broth overflows through the second weir 212, while the lignin sludge gets collected in the sump 206 of the feed tray 114.
[0073] In an exemplary embodiment, at least one sieve tray 108 may include multiple protrusions/upward notches 214 arranged in a staggered pattern across its upper surface. These upward notches 214 are strategically designed to disrupt the flow of the biomass slurry and ethanol broth passing through the sieve tray 108, to prevent accumulation and clogging of the lignin sludge, which is commonly present in biomass slurries with high lignin content. The design of the upward notches 214 plays a critical role in maintaining smooth flow through the distillation column and improving overall system efficiency. One or more of the upward notches 214 may have a triangular shape, which enhances their ability to break up the flow and redirect the liquid, further reducing the chances of clogging. The staggered configuration of the upward notches 214 ensures that the flow is constantly disturbed, preventing the formation of blockages that could disrupt the distillation process. This design feature is particularly important in dealing with lignin-rich biomass, as lignin can quickly accumulate and cause operational issues in conventional distillation towers. Thus, the inclusion of these specialized protrusions/upward notches 214 significantly enhances the performance and reliability of the distillation unit 102 by improving the handling of viscous, lignin-laden slurries.
[0074] The feed inlet device 104 positioned within the distillation tower 102 such that the biomass slurry and ethanol broth passes through the feed inlet device 104 before being supplied to any of the sieve trays 108 and the feed trays 114. In an exemplary embodiment, the feed inlet device 104 may be positioned between two feed trays 114. In an exemplary embodiment, the feed inlet device 104 may be positioned between a sieve tray 108 and a feed tray 114. The feed inlet device 104 is configured to efficiently separate vapour and liquid phases during interaction of the vapour and the biomass slurry and ethanol broth by utilizing kinetic energy from the incoming biomass slurry and ethanol broth.
[0075] In an exemplary embodiment, the drain outlet pipe 210 may be controlled by an actuated valve connected to the second set of spray nozzles 204. The actuation of this valve is coordinated with a timer and ethanol specification controller, operating in tandem with the ratio controller 126. As a result, whenever the second set of spray nozzles 204 is activated, the valve is simultaneously triggered to open the drain outlet pipe 210. This allows the washed liquid and lignin sludge to flow into the settling tanks 136 and 138. In a further embodiment, a portion of the biomass slurry and ethanol broth, which is laden with lignin sludge, is directed through an outlet downcomer to the bottom-most sieve tray 108. From there, the process continues in a sequential manner, ensuring that most of the lignin stillage follows its intended path toward the settling tanks 136 and 138. This controlled flow is essential to maintain the efficiency of the separation process and to ensure that the by-products are properly collected and separated for further processing or disposal.
[0076] The drain outlet pipe 210 may be controlled by an actuated valve connected with the second set of spray nozzles 204, such that actuation of the valve is dual-actuated with timer-controlled and ethanol specification-controlled in tandem with the ratio controller 126. Therefore, whenever the second set of spray nozzles 204 are actuated, the valve is actuated to open the drain outlet pipe 210 and enable the washed liquid and lignin sludge to flow to the settling tanks 136, 138. In an exemplary embodiment, a percentage of the biomass slurry and ethanol broth laden with lignin sludge escapes through an outlet downcomer to the bottom-most sieve tray 108, and the process continues in a sequential manner with most of the lignin stillage finding its route to the settling tanks 136, 138.
[0077] In an exemplary embodiment, the lignin-laden biomass slurry and ethanol broth that escapes from the last tray 108/114 reaches the liquid pool at the bottom of the distillation tower 102 and mixes with the clean liquid coming from the centrifuge 140. In the distillation tower 102, there is an outlet nozzle for the liquid to flow to the reboiler 106 from the liquid pool. To remove lignin slipping into the reboiler liquid pool, an additional sump may be provided at the base of the outlet nozzle (for the reboiler liquid flow). The sump allows for additional settling time, and there may be provided an additional slurry nozzle at the base of the distillation tower 102 to transport the slurry to the settling tanks 136, 138. This slurry may be mixed with the slurry coming from individual drain outlet pipes 210 provided on each feed tray 114, with the drain outlet pipe valve actuated by in synchronization with actuation of the spray nozzles 112, 204. Thus, all lignin content, undigested biomass fibers, untrapped silt and mud, unconverted cellulose, unconverted hemicellulose, unconverted arabinan, unconverted extractives, unconverted proteins, biomass ash, urea, DAP, molasses, inorganic mineral salts (neutralization products), inorganic antifoam agent residues, dead enzymatic mass, and dead yeast mass are 100% removed from the distillation tower 102 without compromising the ethanol specification quality and ensuring uninterrupted, trouble-free operation of the trays 108, 114, free from lignin lumps and nucleation-assisted lignin agglomerates.
[0078] The feed inlet device 104 is configured to receive and supply the biomass slurry and ethanol broth to any of the sieve trays 108 and the feed trays 114. The feed inlet device 104 includes a plurality of corrugated blades coupled to a shaft accommodated within a casing, and configured to rotate about a rotational axis of the shaft upon supply of the biomass slurry and ethanol broth into the casing; a plurality of protrusions/upward notches positioned at a bottom of the casing in a staggered manner to disrupt flow of the lignin sludge and enable collection of the lignin sludge into a downcomer of the feed inlet device.
[0079] Referring to FIGs. 3A and 3B, the feed inlet device 104 is designed to receive and deliver the biomass slurry and ethanol broth to the sieve trays 108 and feed trays 114. The feed inlet device 104 includes a turbine assembly 302, which is equipped with multiple corrugated blades 304 attached to a shaft 306 housed within a casing 308, as depicted in FIG. 3B. The corrugated blades 304 are designed to rotate around the shaft’s rotational axis when the biomass slurry and ethanol broth is introduced into the casing 308, eliminating the need for an external power source for rotation of the corrugated blades 304. Additionally, the feed inlet device 104 is equipped with several protrusions/upward notches 310 at the bottom of the casing 308, arranged in a staggered formation. These upward notches 310 are appropriately positioned on the bottom of the casing 308 to disrupt the flow of lignin sludge and allow it to be directed into a downcomer 216 within the feed inlet device 104, as shown in FIG. 2.
[0080] In an exemplary embodiment, the controller of the distillation tower 102 may be configured to monitor accumulation of the biomass slurry and ethanol broth on the corrugated blades 304 of the feed inlet device 104. The controller may also be configured to control actuation of the washing nozzles 314 based on pre-determined washing cycles, and one or more parameters pertaining to purity of the ethanol to be produced. The controller may also be configured to actuate the one or more washing nozzles 314 in response to ethanol specification disturbances caused by any or a combination of accumulation of the biomass slurry and ethanol broth on the corrugated blades 304, and clogging of the sieve trays 108 and/or the feed trays 114.
[0081] Each corrugated blade 304 may have a proximal end 304-1 attached to the shaft 306 and a distal end 304-2 extending radially into the casing 308. The height of the corrugated blade 304 may be smaller at the distal end 304-2 than at the proximal end 304-1. The corrugated blade 304 may have a curved shape that gradually decreases in height from the proximal end 304-1 to the distal end 304-2, with a sharp decrease in height at an intermediate position 304-3 between the two ends.
[0082] The feed inlet device 104 may further include a feed entry zone/region that houses the corrugated blades 304 and includes a feed entry nozzle 312, which is designed to receive the biomass slurry and ethanol broth at a pre-defined rate. In addition, the feed inlet device 104 may contain a washing region equipped with one or more washing nozzles 314 within the casing 308, designed to circulate a washing liquid. This helps clean the accumulated biomass slurry and ethanol broth from the corrugated blades 304, reducing unwanted entrainment and improving the separation efficiency. To facilitate the removal of the collected lignin sludge, the feed inlet device 104 may be equipped with a drain outlet pipe 316 located at the downcomer 216. The drain outlet pipe 316 is controlled by a valve that is synchronized with the first or second set of spray nozzles 112, 204, ensuring efficient transfer of the lignin sludge to settling tanks 136 and 138 for further processing. The drain outlet pipe 316 ensures that removed micro-lignin does not re-enter the distillation tower 102.
[0083] The turbine-type feed inlet device 104 improves phase separation and micro-lignin handling. The feed inlet device 104 is responsible for introducing the ethanol broth into the distillation tower 102. The feed inlet device 104 ensures efficient phase separation between ethanol and non-ethanol components, including micro-lignin particles. The design of the feed inlet device 104 helps promote optimal mixing and dispersion, which aids in the effective separation of the phases and collection of lignin residues.
[0084] The distillation tower 102 is designed with several critical sections that contribute to efficient ethanol production. One of these key sections is the rectification section, which plays an essential role in ensuring that the ethanol produced meets the stringent purity standards outlined in IS15464:2004. This section works by separating ethanol from other volatile components in the mixture. The rectification section allows for the precise control of the ethanol concentration, ensuring that the final product reaches the desired alcohol content. Beyond purification, the rectification section is also designed to recover valuable by-products from the distillation process. This recovery enhances the overall efficiency and yield of the system, reducing waste and optimizing resource use. The distillation tower 102 may include a stripping section, which focuses on the removal of unwanted components such as water and non-ethanol substances. The stripping section utilizes the principle of vapour-liquid equilibrium, where vapour is generated and used to selectively drive off these undesirable compounds. This separation process ensures that the ethanol remaining in the system is of higher purity. The stripping section is critical in maintaining the final product's quality, ensuring that the ethanol meets the high standards required for industrial and commercial use. By efficiently removing impurities, the stripping section contributes to the consistency and overall quality of the final ethanol product.
[0085] FIG. 4 illustrates an exemplary flow chart representation of a method 400 for producing ethanol with a biomass slurry and ethanol broth having high or very high lignin content. The method 400 is performed by the apparatus 100 depicted in FIG. 1. The biomass slurry and ethanol broth may contain about 25-30% w/w lignin sludge. In an embodiment, the biomass slurry and ethanol broth may contain about 20-25% w/w lignin sludge.
[0086] The method 400 includes a step 402 of receiving, by the feed inlet device 104 of the distillation unit 102, a biomass slurry and ethanol broth at a pre-defined rate. The method 400 also includes, at step 404, boiling, by the heat exchanger/reboiler 106, a liquid at the bottom of the distillation tower 102 to generate vapour traversing in the vertically upward direction within the distillation tower 102, and, at step 406, segregating, by rotation of a plurality of corrugated blades 304 of the feed inlet device 104, lignin sludge present in the biomass slurry and ethanol broth. Thereafter, the method 400 proceeds to a step 408 of supplying the biomass slurry and ethanol broth to the at least one sieve tray 108 having the perforations 110 to enable passage for the vapour to pass therethrough. The sieve tray 108 may include multiple protrusions/upward notches 214 arranged in a staggered pattern across its upper surface. These protrusions/upward notches 214 are strategically designed to disrupt the flow of the biomass slurry and ethanol broth passing through the sieve tray 108, to prevent accumulation and clogging of the lignin sludge, which is commonly present in biomass slurries with high lignin content.
[0087] The method 400 also includes a step 410 of segregating, by pall rings 202 of the at least one feed tray 114 positioned downstream of the at least one sieve tray 108, lignin sludge from the biomass slurry and ethanol broth, and a step 412 of allowing, by the chimneys 208 of the at least one feed tray 114, the vapour generated by the heat exchanger/reboiler 106 to escape therethrough in the vertically upward direction.
[0088] The method 400 further includes a step 414 of regulating, by a controller of the apparatus 100, one or more washing nozzles 314 configured within the casing 308 of the feed inlet device 104 to circulate a washing liquid for cleaning accumulated biomass slurry and ethanol broth from the plurality of corrugated blades, actuation of the first set of spray nozzles 112 to control dispensing of the first cleaning mixture over the sieve trays 108 to prevent clogging of the biomass slurry and ethanol broth received by the sieve trays 108, and actuation of the second set of spray nozzles 204 to control dispensing of the second cleaning mixture over the feed trays 114 to enable collection of the lignin sludge into the sumps 206 thereof. The step 414 of regulating may include controlling actuation of the washing nozzles 314, the first set of spray nozzles 112 and the second set of spray nozzles 204 based on pre-determined washing cycles. The method 400 may also include a step of monitoring, by the controller, clogging of the lignin sludge received by any of the sieve trays 108 and the feed trays 114, and monitoring accumulation of the biomass slurry and ethanol broth on the corrugated blades 304 of the feed inlet device 104. The method 400 may further include controlling, by the controller, actuation of the washing nozzles 314, the first set of spray nozzles 112 and the second set of spray nozzles 204 based on pre-determined washing cycles and one or more parameters pertaining to purity of the ethanol to be produced.
[0089] The method 400 may include a step of supplying the lignin sludge collected in the sumps 206 of the feed trays 114 to the settling tanks 136, 138 of the distillation tower 102. The method 400 may further include a step of separating, by the centrifuge 140 of the distillation tower 102, residual sludge from the lignin sludge received by the settling tanks 136, 138. The method 400 may also include supplying a liquid output from the centrifuge 140 to the heat exchanger/reboiler 106 to facilitate generation of the vapour. The method 400 may include extracting, by the outlet nozzle 120 of the distillation tower 102, purified ethanol from the biomass slurry and ethanol broth.
[0090] The method 400 may include regulating, by the first weirs of the sieve trays 108, flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in the downstream direction only when the biomass slurry and ethanol broth overflows through the first weirs. The method 400 may further include regulating, by the second weirs 212 of the feed trays 114, flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in the downstream direction only when the biomass slurry and ethanol broth overflows through the second weirs 212.
[0091] With the apparatus 100 and the method 400 of the present disclosure, the purity of the ethanol azeotrope (95.5 mole %) distilled from the distillation tower 102 can be achieved on a continuous process basis without any bottlenecks or intermittent troubleshooting of the distillation tower 102 due to the formation of C-5 sugar (xylan) and C-6 sugar (glucose) assisted nucleated lignin agglomerates and lumps. After the formation of the ethanol azeotrope (95.5 mole % ethanol) as a product from the distillation tower 102, the product stream may be routed to a dehydration column packed with molecular sieves. These molecular sieves help reduce the residual water content in the ethanol azeotropic mixture. Ethanol quality (99.5 mol %, at 15.6/15.6°C Min.) and the standard as per Indian specifications (IS 15464:2004) for anhydrous ethanol, suitable for use in automotive fuel, can be easily achieved as the final product from the outlet of the molecular sieves. The ethanol product may then be routed to a run-down storage tank for final loading into tankers via the gantry.
[0092] The apparatus 100 and method 400 of the present disclosure provide significant advantages over conventional distillation systems, enhancing efficiency, cost-effectiveness, and sustainability. Key benefits include uninterrupted ethanol production, achieved through the turbine-type feed inlet device 104 and sludge removal system, including the arrangement of the sieve trays 108 and the feed trays 114, which prevent clogging and downtime. The apparatus 100 ensures superior ethanol purity (95.5 mole%) in compliance with IS15464:2004 standard and efficiently separates lignin, reducing maintenance costs. The apparatus 100 optimizes energy use, minimizing heat losses and power consumption, while recovering valuable by-products like methanol and acetic acid to improve economic viability. The automated system control, with the dynamic ratio controller 126, reduces human intervention. Additionally, the apparatus 100 supports India’s Net Zero 2070 goal by reducing fossil fuel dependence. The scalability of the apparatus 100 and the method 400 makes them suitable for both small and large bio-refinery operations, improving the economic, operational, and environmental efficiency of 2G ethanol production for long-term industrial use.
[0093] Thus, the apparatus 100 and method 400 of the present disclosure provide highly efficient processing of biomass slurries with high or extremely high lignin content, enabling the production of high ethanol yields. By addressing and overcoming lignin-related challenges, the method 400 significantly enhances enzymatic hydrolysis and fermentation efficiency, leading to improved ethanol output. Compared to conventional ethanol production techniques, both the apparatus 100 and method 400 reduce the need for excessive energy consumption and harsh chemicals, resulting in lower environmental impact and reduced operational costs.
[0094] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0095] The present disclosure provides an apparatus/distillation tower and method for efficiently processing biomass slurries with high lignin content, enabling high ethanol yields by distillation column that has novel arrangement of engineered trays. The apparatus incorporates sieve trays having a combination of pall rings and risers, and a feed inlet device equipped with corrugated blades and upward protrusion/notches. All these innovative schemes enables high lignin-laden ethanol broth to separate out, enabling sufficient mass transfer within the distillation tower to achieve desired purity and specification of fuel grade ethanol.
[0096] The present disclosure provides a method for producing ethanol from biomass slurries that eliminates the need for excessive energy input or harsh chemicals. This reduces the environmental impact and lowers the operational costs compared to conventional processes that rely on aggressive chemicals and energy-intensive methods.
[0097] The present disclosure provides a method that focuses on reducing energy consumption, and chemical use, making the apparatus economically viable and competitive for large-scale commercial ethanol production. An environmentally sustainable bioethanol production process is also promoted by reducing the need for harsh chemicals, lowering energy consumption, and minimizing by-product generation, contributing to the sustainability of biofuels as a renewable energy source.
[0098] The present disclosure provides an apparatus designed to be adaptable to a wide variety of biomass feedstocks with high lignin content, making it scalable and versatile for different industrial applications and feedstock types.
[0099] The present disclosure provides an apparatus and a method that are easily scalable for large-scale bioethanol production, maintaining high efficiency and low operational costs. This scalability helps meet the growing global demand for biofuels while ensuring efficient production processes.
, Claims:1. An apparatus (100) for producing ethanol with a biomass slurry and ethanol broth having high lignin content, comprising:
a distillation unit (102) configured to receive and process the biomass slurry and ethanol broth to reduce lignin content thereof, the distillation unit (102) comprising:
a reboiler (106) configured to boil a liquid at a bottom of the distillation unit (102) to generate vapour traversing in a vertically upward direction within the distillation unit (102);
at least one sieve tray (108) having a plurality of perforations (110) to enable passage for the vapour to pass therethrough, and a first set of spray nozzles (112) configured to spray a first cleaning mixture over the at least one sieve tray (108) to prevent clogging of lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray (108);
at least one feed tray (114) positioned downstream of the at least one sieve tray (108), the at least one feed tray (114) comprising:
a plurality of pall rings (202) to segregate lignin sludge from the biomass slurry and ethanol broth;
a second set of spray nozzles (204) configured to spray a second cleaning mixture over the at least one feed tray (114) to prevent clogging of the lignin sludge present in the biomass slurry and ethanol broth received by the at least one feed tray (114), and enable collection of the lignin sludge into a sump (206) of the at least one feed tray (114); and
a plurality of risers (208) configured to allow the vapour generated by the reboiler (106) to escape therethrough in the vertically upward direction;
a feed inlet device (104) configured to receive and supply the biomass slurry and ethanol broth to any of the at least one sieve tray (108) and the at least one feed tray (114), the feed inlet device (104) comprising:
a plurality of corrugated blades (304) coupled to a shaft (306) accommodated within a casing (308), and configured to rotate about a rotational axis of the shaft (306) upon supply of the biomass slurry and ethanol broth into the casing (308);
a plurality of upward notches (310) positioned at a bottom of the casing (308) in a staggered manner to disrupt flow of the lignin sludge and enable collection of the lignin sludge into a downcomer (216) of the feed inlet device (104).

2. The apparatus (100) as claimed in claim 1, wherein the first set of spray nozzles (112) are timer-controlled to dispense the first cleaning mixture over the at least one sieve tray (108) in pre-defined time intervals.

3. The apparatus (100) as claimed in claim 1, wherein the second set of spray nozzles (204) are timer-controlled to dispense the second cleaning mixture over the at least one feed tray (114) in pre-defined time intervals.

4. The apparatus (100) as claimed in claim 3, wherein the distillation unit (102) comprises a controller configured to:
monitor clogging of the lignin sludge received by the any of the at least one sieve tray (108) and the at least one feed tray (114);
monitor accumulation of the biomass slurry and ethanol broth on the plurality of corrugated blades (304) of the feed inlet device (104); and
control actuation of the first set of spray nozzles (112) and the second set of spray nozzles (204), and one or more washing nozzles (314) configured within the casing (308) of the feed inlet device (104) based on pre-determined washing cycles and one or more parameters pertaining to purity of the ethanol to be produced.

5. The apparatus (100) as claimed in claim 1, wherein the first cleaning mixture comprises equimolar mixture of acetic acid and methanol.

6. The apparatus (100) as claimed in claim 1, wherein the second cleaning mixture comprises non-equimolar mixture of acetic acid and methanol.

7. The apparatus (100) as claimed in claim 6, further comprising a ratio controller configured to control the equimolar mixture of methanol and acetic acid in a ratio of about 3% to 6%.

8. The apparatus (100) as claimed in claim 1, wherein the biomass slurry and ethanol broth contains about 25-30% w/w lignin sludge.

9. The apparatus (100) as claimed in claim 1, wherein the biomass slurry and ethanol broth contains about 21-25% w/w lignin sludge.

10. The apparatus (100) as claimed in claim 1, wherein the at least one sieve tray (108) and the at least one feed tray (114) are arranged in a staggered manner relative to one another along a height of the distillation unit (102).

11. The apparatus (100) as claimed in claim 1, wherein each corrugated blade of the plurality of corrugated blades (304) has a proximal end (304-1) coupled to the shaft (306) and a distal end (304-2) extending into the casing (308) in a radial direction of the shaft (306), and wherein a height of the corrugated blade (304) at the distal end (304-2) is smaller than the height of corrugated blade (304) at the proximal end (304-1).

12. The apparatus (100) as claimed in claim 11, wherein the corrugated blade (304) has a curved profile extending from the proximal end (304-1) to the distal end (304-2), and wherein the height of the corrugated blade (304) decreases drastically at an intermediate position (304-3) between the proximal end (304-1) and the distal end (304-2).

13. The apparatus (100) as claimed in claim 4, wherein the feed inlet device (104) comprises:
a feed entry region accommodating the plurality of corrugated blades (304), and comprising a feed entry nozzle (312) for receiving the biomass slurry and ethanol broth at a pre-defined rate; and
a washing region accommodating the one or more washing nozzles (314) configured within the casing (308) of the feed inlet device (104), and adapted to receive and circulate a washing liquid for cleaning accumulated biomass slurry and ethanol broth from the plurality of corrugated blades (304).

14. The apparatus (100) as claimed in claim 1, wherein the at least one sieve tray (108) comprises a plurality of upward notches (214) formed in a staggered configuration over an upper surface thereof to disrupt flow and prevent clogging of the lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray (108).

15. The apparatus (100) as claimed in claim 14, wherein each of the plurality of upward notches (214) has a triangular-shaped profile.

16. The apparatus (100) as claimed in claim 1, wherein the distillation unit (102) comprises one or more settling tanks (136, 138) configured to receive the lignin sludge collected in the sump (206) of the at least one feed tray (114).

17. The apparatus (100) as claimed in claim 16, wherein the distillation unit (102) comprises a centrifuge (140) configured to separate residual sludge from the lignin sludge received by the one or more settling tanks, and wherein a liquid output from the centrifuge (140) is supplied to the reboiler (106) to generate the vapour.

18. The apparatus (100) as claimed in claim 16, wherein the at least one feed tray (114) comprises a drain outlet pipe (210) positioned at the sump (206) to facilitate removal of the collected lignin sludge, the drain outlet pipe (210) being controlled by a valve synchronized with the second set of spray nozzles (204) to optimize transfer of the collected lignin sludge to the one or more settling tanks (136, 138).

19. The apparatus (100) as claimed in claim 1, wherein the distillation unit (102) comprises an outlet nozzle configured to extract purified ethanol from the biomass slurry and ethanol broth.

20. The apparatus (100) as claimed in claim 1, wherein the plurality of pall rings (202) are arranged on the at least one feed tray (114) in a random packing arrangement to facilitate collection of the lignin sludge into the sump (206).

21. The apparatus (100) as claimed in claim 1, wherein the at least one feed tray (114) comprises:
a first feed tray (114-1) having an arrangement of the plurality of pall rings (202), the second set of spray nozzles (204) and the plurality of risers (208) in a first configuration; and
a second feed tray (114-2) having an arrangement of the plurality of pall rings (202), the second set of spray nozzles (204) and the plurality of risers (208) in a second configuration different from the first configuration, wherein
the first feed tray (114-1) and the second feed tray (114-2) are arranged in a staggered manner relative to one another along the height of the distillation unit (102).

22. The apparatus (100) as claimed in claim 1, wherein the at least one sieve tray (108) comprises a first set of weirs or downcomers to enable supply of the biomass slurry and ethanol broth in a downstream direction only when the biomass slurry and ethanol broth overflows through the first set of weirs or downcomers.

23. The apparatus (100) as claimed in claim 1, wherein the at least one feed tray (114) comprises a second set of weirs or downcomers (212) to allow supply of the biomass slurry and ethanol broth in the downstream direction only when the biomass slurry and ethanol broth overflows through the second set of weirs or downcomers (212).

24. A method (400) for producing ethanol with a biomass slurry and ethanol broth having high lignin content, comprising the steps of:
receiving, by a feed inlet device (104) of a distillation unit (102), the biomass slurry and ethanol broth at a pre-defined rate;
boiling, by a reboiler (106), a liquid at a bottom of the distillation unit (102) to generate vapour traversing in a vertically upward direction within the distillation unit (102);
segregating, by rotation of a plurality of corrugated blades (304) of the feed inlet device (104), lignin sludge present in the biomass slurry and ethanol broth;
supplying, by the feed inlet device (104), the biomass slurry and ethanol broth to at least one sieve tray (108) having a plurality of perforations (110) to enable passage for the vapour to pass therethrough;
segregating, by a plurality of pall rings (202) of at least one feed tray (114) positioned downstream of the at least one sieve tray (108), lignin sludge from the biomass slurry and ethanol broth;
allowing, by a plurality of risers (208) of the at least one feed tray (114), the vapour generated by the reboiler (106) to escape therethrough in the vertically upward direction;
regulating, by a controller, actuation of one or more washing nozzles (314) configured within the casing (308) of the feed inlet device (104) to circulate a washing liquid for cleaning accumulated biomass slurry and ethanol broth from the plurality of corrugated blades (304), actuation of a first set of spray nozzles (112) to control dispensing of a first cleaning mixture over the at least one sieve tray (108) to prevent clogging of the biomass slurry and ethanol broth received by the at least one sieve tray (108), actuation of a second set of spray nozzles (204) to control dispensing of a second cleaning mixture over the at least one feed tray (114) to enable collection of the lignin sludge into a sump (206) of the at least one feed tray (114).

25. The method (400) as claimed in claim 24, where the step of regulating comprises controlling actuation of the one or more washing nozzles (314), the first set of spray nozzles (112) and the second set of spray nozzles (204) based on pre-determined washing cycles.

26. The method (400) as claimed in claim 24, wherein the biomass slurry and ethanol broth contains about 25-30% w/w lignin sludge.

27. The method (400) as claimed in claim 24, wherein the biomass slurry and ethanol broth contains about 21-25% w/w lignin sludge.

28. The method (400) as claimed in claim 24, further comprising:
supplying the lignin sludge collected in the sump (206) to one or more settling tanks; and
separating, by a centrifuge of the distillation unit (102), residual sludge from the lignin sludge received by the one or more settling tanks; and
supplying a liquid output from the centrifuge to the reboiler (106) to generate the vapour.

29. The method (400) as claimed in claim 24, further comprising extracting, by an outlet nozzle of the distillation unit (102), purified ethanol from the biomass slurry and ethanol broth.

30. The method (400) as claimed in claim 24, further comprising:
monitoring, by a controller, clogging of the lignin sludge received by the any of the at least one sieve tray (108) and the at least one feed tray (114);
monitor accumulation of the biomass slurry and ethanol broth on the plurality of corrugated blades (304) of the feed inlet device (104); and
controlling, by the controller, actuation of the first set of spray nozzles (112) and the second set of spray nozzles (204) based on pre-determined washing cycles and one or more parameters pertaining to purity of the ethanol to be produced.

31. The method (400) as claimed in claim 24, further comprising:
regulating, by a first set of weirs or downcomers of the at least one sieve tray (108), flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in a downstream direction only when the biomass slurry and ethanol broth overflows through the first set of weirs or downcomers; and
regulating, by a second set of weirs or downcomers of the at least one feed tray (114), flow of the biomass slurry and ethanol broth such that the biomass slurry and ethanol broth is supplied in the downstream direction only when the biomass slurry and ethanol broth overflows through the second set of weirs or downcomers.