Description:TECHNICAL FIELD
[0001] The present disclosure relates to ethanol production plants. More specifically, the present disclosure pertains to a process and a distillation column system for 2G Ethanol Bio-Refinery with Filamentous-Residues & High-Lignin Laden Feed like bamboo feed.

BACKGROUND
[0002] Ethanol production from renewable biomass sources has gained significant attention as an environmentally friendly alternative to fossil fuels. Among the various feedstocks available for bioethanol production, lignocellulosic biomass, has proven to be one of the most promising sources. However, lignocellulosic biomass consists of three main components, i.e., cellulose, hemicellulose, and lignin.
[0003] Lignin is a complex, non-sugar-based polymer found in plant cell walls, primarily functioning as a structural support material, providing rigidity and resistance to degradation. However, lignin cannot be used directly as feedstock for ethanol production through microbial fermentation via the enzymatic route, as it is highly resistant to breakdown by most enzymes and microbes. This resistance makes it a significant challenge in bioethanol production, as lignin inhibits both microbial growth and fermentation processes, thereby reducing the overall efficiency and economic viability of bioconversion. Lignin's presence in biomass, as the second most abundant component after cellulose, plays a pivotal role in the economics of biofuels. While it cannot be fermented into ethanol, lignin can be utilized as a valuable source of energy. When burned, lignin generates a substantial amount of heat, making it an excellent feedstock for combined heat and power (CHP) systems. In a bio-refinery, lignin can be used in a sustainable and environmentally friendly manner to produce energy, enhancing the overall efficiency and economic performance of the biofuel production process by contributing to the generation of renewable energy. Thus, while lignin is a barrier to ethanol production, its energy potential makes it an important component of the bio-refinery concept.
[0004] The challenge in bioethanol production from lignocellulosic biomass lies in the efficient conversion of cellulose and hemicellulose into fermentable sugars while minimizing the impact of lignin. Traditionally, pre-treatment processes such as chemical, physical, and biological processes have been employed to break down the lignin and enhance the accessibility of cellulose and hemicellulose. However, these processes often suffer from high energy requirements, the generation of toxic by-products, and the need for expensive chemical reagents. Additionally, the inherent heterogeneity of lignocellulosic biomass and its varying lignin content poses another difficulty. Biomasses with high lignin content are particularly difficult to treat and require more aggressive and costly pre-treatment processes.
[0005] Using filamentous residues and high-lignin laden feed in bamboo for ethanol production presents several challenges that can hinder the efficiency and economic viability of the process. One of the primary issues is the low ethanol yield due to the high lignin content, which acts as a barrier, preventing efficient access to cellulose and hemicellulose, the main sources of fermentable sugars. Filamentous residues further complicate this by containing non-fermentable components, reducing the overall yield of ethanol. The pretreatment process becomes more energy-intensive and costly, as high-lignin feeds require rigorous processs like steam explosion or acid hydrolysis to break down the lignin and release fermentable sugars. This also increases chemical usage, leading to higher operational costs and chemical waste. Additionally, lignin can bind to enzymes used in saccharification, reducing their efficiency and requiring larger quantities of enzymes, while filamentous residues may contain inhibitors that further slow down the conversion process.
[0006] Fermentation faces challenges as well, as pretreatment can generate by-products like furfural and phenolic compounds, which are toxic to fermenting microorganisms such as yeast, inhibiting ethanol production. The presence of lignin and filamentous residues creates an unfavorable environment for microbes, leading to slower fermentation rates and lower yields. The complex breakdown of these materials also results in longer processing times, reducing overall efficiency. Waste management becomes another significant issue, as residual lignin and filamentous residues require proper disposal or repurposing, adding complexity and cost to the process. Improper disposal can also lead to environmental pollution.
[0007] From an economic perspective, the higher production costs associated with pretreatment, enzyme usage, and waste management make the process less viable compared to using low-lignin feedstocks. Reduced ethanol yields and increased operational costs further impact profitability. Technical limitations, such as scaling challenges and the need for extensive process optimization, add to the difficulties, making consistent and efficient ethanol production from such feedstocks time-consuming and costly. While bamboo is a promising feedstock due to its high cellulose content, the presence of filamentous residues and high lignin significantly complicates the process, necessitating advanced technologies and alternative solutions to improve feasibility.
[0008] Lignin-laden stillage, when not effectively managed, can accumulate on the internal components of a distillation tower, particularly on sieve trays where the fractionation liquid flows. The sieve trays play a crucial role in allowing the vapor and liquid to interact, promoting the separation of components based on their boiling points. However, the accumulation of lignin sludge and filamentous residues on these trays can significantly disrupt this process. As the sludge builds up, it obstructs the free flow of liquids from the inlet downcomer to an outlet downcomer thereof, which is vital for maintaining the proper distribution of liquid across the tray. This blockage reduces the sieve tray’s efficiency by hindering mass transfer, the process through which components are separated within the distillation column, thus lowering the effectiveness of the distillation process. As a result, the overall performance of the distillation tower deteriorates, leading to less efficient separation and, consequently, lower-quality products.
[0009] Conventional techniques for dealing with lignin accumulation often involve labor-intensive manual cleaning or periodic shutdowns for maintenance. These procedures can be highly disruptive, leading to unscheduled downtimes that interrupt continuous operations. The need for frequent maintenance not only affects production timelines but also incurs significant economic losses, both in terms of lost throughput and the cost of labor and resources required for cleaning. Furthermore, repeated downtime for maintenance can affect the long-term operational efficiency of the system, leading to an overall increase in operational costs and a decrease in profitability. Therefore, the need for an effective and continuous solution to manage lignin-laden stillage is critical in maintaining smooth operations, enhancing distillation efficiency, and reducing the economic impact of manual maintenance processes.
[0010] In light of the above challenges, there is a need in the art for a more efficient solution for producing ethanol from biomass slurries & ethanol broth that contain filamentous residues and high lignin content. The present invention addresses these challenges by providing an apparatus and process for the efficient production of ethanol from biomass slurries & ethanol broth that contain Filamentous-Residues & High-Lignin content. By optimizing pre-treatment, enzymatic hydrolysis, fermentation steps and modifying the sieve trays, the invention offers a more efficient, cost-effective, and environmentally sustainable solution for bioethanol production. The apparatus also allows for scaling up of bioethanol production from a variety of biomass sources, improving the economic feasibility and sustainability of biofuels as a renewable energy source.

OBJECTS OF THE PRESENT DISCLOSURE
[0011] An object of the present disclosure is to provide an apparatus that efficiently processes biomass slurries & ethanol broth, particularly those with Filamentous-Residues & High-Lignin content, to produce high yields of ethanol without disruption. Another object of the present disclosure is to reduce operational costs in the production of ethanol from biomass, particularly by reducing energy consumption,. This makes the apparatus and corresponding process more economically viable and competitive in large-scale commercial bioethanol production.
[0012] Another object of the present disclosure is to provide an environmentally sustainable solution for bioethanol production. The apparatus promotes an environmentally friendly process for ethanol production by reducing energy consumption, and minimizing the generation of by-products. By improving the efficiency of ethanol production, the apparatus contributes to the overall sustainability of biofuels as a renewable energy source.
[0013] Another object of the present disclosure is to provide a flexible apparatus that can adapt to varying biomass feedstocks with with Filamentous-Residues & High-Lignin content. This flexibility allows the apparatus to be used with a wide range of feedstocks, making it scalable and versatile for different industrial applications.
[0014] Another object of the present disclosure is to improve the scalability and efficiency of bioethanol production. The apparatus and corresponding process are capable of being easily scaled up for large-scale bioethanol production while maintaining high efficiency and low operational costs. The scalability of the apparatus of the present disclosure helps meet the growing global demand for biofuels.

SUMMARY
[0015] Aspects of the present disclosure relate to an apparatus and a process for producing ethanol from biomass slurries & ethanol broth, particularly those with with Filamentous-Residues & High-Lignin lignin content. The apparatus and the process of the present disclosure reduce operational costs and enhance the overall yield of ethanol.
[0016] In an aspect, the present disclosure discloses an apparatus for producing ethanol with a biomass slurry having with Filamentous-Residues & High-Lignin content. The apparatus includes a distillation unit configured to receive and process the biomass slurry to effectively manage lignin content and undigested filamentous residues thereof. The distillation unit includes a heat exchanger 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 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 received by the at least one sieve tray.
[0017] The distillation column includes at least one tray with V-notches and risers positioned on the tray. The V-notch structures checks the flow of the filamentous residue with liquid flowing downwardly and the risers allow the rising vapour upwards. Due to this arrangement the feed which is high in filamentous residues and lignin content does not block the rising vapour at the same time is entrained & seperated of to reach the reboiler.
[0018] The distillation unit includes at least one feed tray positioned upstream and downstream of the tray with V-notches and risers discussed above. The at least one feed tray includes a plurality of V-notches and pall rings along with risers to further segregate the filamentous residue and lignin sludge from the biomass slurry. A set of spray nozzles configured to spray a cleaning mixture over the at least one feed tray to prevent clogging of the lignin sludge present in the biomass slurry 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. Risers as usual configured to allow the vapour generated by the heat exchanger to escape therethrough in the vertically upward direction. The pall rings and the v-notches are oriented in anticlockwise directions in three trays (feed tray, above & below feed tray)
[0019] The distillation column is provided with the at least one tray with downward V-notches configured to further trap filamentous material and micro-lignin particles from the ethanol broth.
[0020] Above the reboiler, another sieve tray having a plurality of perforations to enable passage for the vapour to pass therethrough, and a 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 received by the at least one sieve tray.
[0021] According to an embodiment, the number of each type of tray may vary according to hight of the column and the complexity of the biomass used. The number of each type of tray will increase with increase in filamentous residue and lignin content to optimise the removal of the these contents from the distillation column.
[0022] According to an embodiment, the feed trays are constructed from SS-316 stainless steel to withstand corrosive and abrasive conditions caused by C-5 and C-6 sugars.
[0023] According to an embodiment, the spray nozzle system comprises 1 to 20 spray nozzles per sieve tray in particular 4 to 12 spray nozzles per sieve tray.
[0024] According to an embodiment, the the distillation column comprises a stripping section for separating ethanol from undesired components.
[0025] According to an embodiment, the spray nozzle system is configured to operate in co-current, counter-current, and cross-flow directions to dislodge and wash accumulated lignin from the sieve trays.
[0026] According to an embodiment, the automated ratio controller is configured to activate the spray nozzle system at intervals of 5 to 25 minutes particularly 10 to 15 minutes.
[0027] According to an embodiment, a rectification section is provided for maintaining ethanol purity in compliance with IS15464:2004 standards.
[0028] According to an embodiment, the distillation further comprises a drain outlet pipe positioned before the outlet downcomer, the drain outlet pipe configured to remove filamentous residue & lignin-laden slurry from the distillation column.
[0029] According to an embodiment, the drain outlet pipe is controlled by an actuated valve synchronized with the spray nozzle system.
[0030] According to an embodiment, the packed bed in the risers tray comprises random packing to capture suspended lignin and prevent entrainment into vapor streams.
[0031] According to an embodiment, the 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.
[0032] 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.
[0033] 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 also be configured to control 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.
[0034] 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.
[0035] 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.
[0036] According to another embodiment, the biomass slurry may contain about 21% to 25% w/w lignin sludge. According to another embodiment, the the feed tray with downward V-notches is designed to handle a feed composition comprising 21% to 25% lignin by weight
[0037] 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.
[0038] According to an embodiment, the distillation unit may include a feed entry nozzle configured to supply the biomass slurry to any of the at least one sieve tray and the at least one feed tray at a pre-defined rate.
[0039] 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.
[0040] 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 to generate the vapour.
[0041] 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.
[0042] According to an embodiment, the distillation unit may include an outlet nozzle configured to extract purified ethanol from the biomass slurry.
[0043] 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.
[0044] According to an embodiment, the at least one feed tray may include a first feed tray having an arrangement of the plurality of V-notches, pall rings and risers which may be arranged in any order on the tray based on the requirement with the first set of spray nozzles in a first configuration. A second feed tray having an arrangement of the plurality of V-notchs and risers only with the second set of spray nozzles 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.
[0045] According to an embodiment, the trays with first configuration may be provided upwards and downwards i.e. in both sides of the trays with second configuration described above.
[0046] According to an embodiment, the at least one sieve tray may include a first weir to enable supply of the biomass slurry in a downstream direction only when the biomass slurry overflows through the first weir.
[0047] According to an embodiment, the at least one feed tray may include a second weir to allow supply of the biomass slurry in the downstream direction only when the biomass slurry overflows through the second weir.
[0048] According to another aspect of the present disclosure, a process for producing ethanol with a biomass slurry having filamentous residues and high lignin content is disclosed. The process includes receiving, by a feed entry nozzle of a distillation unit, the biomass slurry at a pre-defined rate. The process includes boiling, by a heat exchanger, a liquid at a bottom of the distillation unit to generate vapour traversing in a vertically upward direction within the distillation unit, and supplying the biomass slurry to at least one sieve tray having a plurality of perforations to enable passage for the vapour to pass therethrough. The process also includes segregating, by a plurality of V-notches positioned at the at least one tray the filamentous residues and separating by pall rings of at least one feed tray positioned downstream of the at least one sieve tray, lignin sludge from the biomass slurry, and allowing, by a plurality of risers of the at least one feed tray, the vapour generated by the heat exchanger to escape therethrough in the vertically upward direction.
[0049] The process further includes passing the ethanol broth through at least one feed tray with downward V-notches to trap filamentous material and micro-lignin particles;
[0050] The process further includes regulating, by a controller, 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 received by the at least one sieve tray, and 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. An equimolar mixture of methanol and acetic acid is injected through the spray nozzle system to break down lignin nucleation sites and prevent agglomeration;
[0051] According to an embodiment, the step of regulating may include controlling actuation of the first set of spray nozzles and the second set of spray nozzles based on pre-determined washing cycles. The activation of the spray nozzle system is adjusted based on ethanol purity and feed composition using an automated ratio controller.
[0052] According to an embodiment, the equimolar mixture of methanol and acetic acid injected by the spray nozzle system comprises 3% to 6% methanol and 3% to 6% acetic acid by volume.
[0053] According to an embodiment, the automated ratio controller adjusts the spray nozzle system activation based on a feedback mechanism triggered by an increase in vapor velocity due to sieve tray clogging.
[0054] According to an embodiment, the lignin-laden slurry removed by the automated sludge removal system is settled in a settling tank for 15 minutes to 4 hours before being sent to a centrifuge for further separation.
[0055] According to an embodiment, the clarified liquid from the centrifuge is recycled back to the reboiler pool liquid for reuse in the spray nozzle system.
[0056] According to an embodiment, the feed tray with downward V-notches is designed to handle a feed composition comprising 21% to 25% lignin by weight.
[0057] According to an embodiment, the process comprises separating ethanol from undesired components in a stripping section.
[0058] According to an embodiment, the stripping section operates at a temperature range of 78°C to 85°C to separate ethanol from water and other impurities.
[0059] According to an embodiment, the process comprises maintaining ethanol purity in a rectification section to achieve 95.5 mole% ethanol in compliance with IS15464:2004 standards.
[0060] According to an embodiment, the rectification section operates at a temperature range of 78°C to 82°C to maintain ethanol purity at 95.5 mole%.
[0061] According to an embodiment, the biomass slurry may contain at least 21-25% w/w lignin sludge. According to another embodiment, the biomass slurry may contain filamentious residues.
[0062] According to an embodiment, the process 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 process may further include supplying a liquid output from the centrifuge to the heat exchanger to generate the vapour.
[0063] According to an embodiment, the process may include extracting, by an outlet nozzle of the distillation unit, purified ethanol from the biomass slurry.
[0064] According to an embodiment, the process 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 process 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.
[0065] According to an embodiment, the process may include regulating, by a first weir of the at least one sieve tray, flow of the biomass slurry such that the biomass slurry is supplied in a downstream direction only when the biomass slurry overflows through the first weir. The process may further include regulating, by a second weir of the at least one feed tray, flow of the biomass slurry such that the biomass slurry is supplied in the downstream direction only when the biomass slurry overflows through the second weir.
[0066] 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
[0067] 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.
[0068] FIG. 1 shows detailed distillation unit with distillation column according to the present invention.
[0069] FIG. 2 shows enlarged view of the distillation column showing the specialized feed tray accoding to the present invention.
[0070] FIG. 3 shows enlarged view of the sieve tray with spary nozzles according to an exemplary embodiment of the present invention.
[0071] FIG. 4 shows the enlarged view highlighting the specialized feed trays with V-notches, Pall rings and risers;
[0072] FIG. 5 shows another feed tray design with the Risers and V-notches only according to an exemplary embodiment of the present invention;
[0073] FIG. 6 shows the Feed Tray with modified wiers according to an exemplary embodiment of the present invention;
[0074] FIG. 7 shows a flow chart depicting the process according to an embodiment of the present invention;

DETAILED DESCRIPTION
[0075] 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.
[0076] The present invention provides a solution to a spectrum of engineering challenges in distillation columns/towers used for bio-ethanol distillation, with feedstock having filamentous residues and high lignin content. In addition to ethanol, Furfural, fusel oil, and Technical Alcohol are produced as side cuts in the distillation column. The quality of the ethanol produced meets the Indian specifications (IS 15464:2004) for anhydrous ethanol for use in automotive fuel, with the desired ethanol content of 99.50% by volume. Ethanol and water form an azeotropic mixture at an ethanol mole percentage of approximately 91% (~96% by volume), preventing further purification by distillation. Molecular membranes are used to achieve the desired high-purity ethanol for blending. The process of ethanol production generally involves pre-treatment of biomass followed by tailored enzymatic hydrolysis of ligno-cellulosic biomass to fermentable sugars (C-5 and C-6 sugars). These sugars are fermented by common yeasts to produce ethanol. The ethanol broth is finally distilled using the distillation column, which contains micro-lignin produced during the steam explosion of the biomass pre-treatment step, dead yeast, enzymatic biomass, water, unutilized nutrients, and unconverted cellulose and hemicellulose. According to the Petroleum Planning & Analysis Cell (PPAC) market economics, with 20% blending of gasoline, 11,178 million liters of ethanol are required in the country. Therefore, the demand for bio-ethanol plants will increase significantly, and the need for novel distillation setups will also rise.
[0077] For brevity, due to the presence of micro-lignin in the ethanol broth, the valves and sieve trays of the distillation column are prone to frequent clogging, requiring a quick and efficient cleaning cycle for each tray. This cleaning cycle is a function of the biomass used, although the process remains feedstock-agnostic. The lignin percentage of the biomass affects the cleaning cycle time of the column. The present invention of the novel distillation tower encompasses robust bio-ethanol distillation capture from bamboo feedstock, and its use in situ in oil and gas refineries coupled with bio-refineries. This present invention provides an innovative solution for distillation of feedstock having filamentous residues and high lignin content for the oil and gas industry, focusing on environmental footprint reduction across global communities, with the holistic goal of addressing the merits and challenges of three-phase distillation in bio-ethanol plants. In response to these challenges, the present invention introduces an apparatus and process for efficiently managing ethanol broth with a lignin-laden stillage.
[0078] Embodiments described herein relate to an apparatus and process for efficiently processing biomass slurries & ethanol broth with filamentous residues and high lignin content to produce high ethanol yields. The apparatus is adaptable to various biomass feedstocks, making it scalable for large-scale commercial bioethanol production, while contributing to the sustainability of biofuels as a renewable energy source.
[0079] FIG. 1 illustrates an exemplary schematic representation of an apparatus 100 for producing ethanol with a biomass slurry having filamentous residues and high lignin content. The apparatus 100 includes a distillation unit (also referred to as “distillation tower” herein) 102 configured to receive and process the biomass slurry to reduce lignin content thereof. The biomass slurry may include bamboo feedstock which contain about 21-25% weight/weight (w/w) lignin sludge and filamentous residues. Though the invention has been described with reference to bamboo feedstock, other feedstocks having high fiber content and high lignin content may be used.
[0080] The distillation tower 102 includes a feed entry nozzle 104 that receives the biomass slurry containing the lignin-laden ethanol broth, and supplies the biomass slurry within the distillation tower 102 for processing. 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 as shown in detailed view of FIG. 3. The sieve tray 108 includes a plurality of perforations 110 to enable passage for the vapour generated by the heat exchanger 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 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 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 in a downstream direction only when the biomass slurry overflows through the first weir.
[0081] The distillation tower 102 also includes one or more feed trays 114 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 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-716 (Stainless Steel) to efficiently facilitate processing of corrosive and abrasive C-5 sugar (xylan) and C-6 sugar (glucose) laden biomass slurry.
[0082] 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 216 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 216, 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. As the vapour rises through the distillation tower 102, it allows for the separation of various components of the biomass slurry based on their boiling points to facilitate production of ethanol with improved purity.
[0083] The distillation tower 102 may include a vapour outlet nozzle 118, which is designed to withdraw the product vapour . This vapour is directed out of the distillation tower 102, 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. 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.
[0084] The distillation tower 102 may include an outlet nozzle 120, which enables extraction of the purified ethanol from the biomass slurry. 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.
[0085] 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.
[0086] 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.
[0087] Referring now to FIG. 2, which shows an enlarged view of the distillation column as shown in FIG. 1 the column include below the sieve tray (not shown in FIG. 2) a feed tray 114 with a combination of inverted V-notches, pall rings and risers placed in sequencial manner. However, it should be noted that these structures may be present in any combination like mixed, parallel or any other combination. The V-notches 201 may be present in one or more rows to entrain and separate of the filamentous residues in the slurry. The pall rings 202 provided trap the high lignin content present in the feedstock. The risers 208 provided on the tray allow the rising vapours to rise through the feed tray without any hindrance. The lignin which is trapped by the pall rings 202 is washed out using the second set of spray nozzels provided on the feed tray 114.
[0088] Downstream the feed tray 114, another feed tray 115 provided only with risers 208 and the V-notches 201 is provided. The feed tray 115 provides an additional check to the fibers present in the feedstock. The risers 208 proide similar function as described above, to pass the vapours upwards through the tray. The V-notches 201 filter the filamentous resiudes futher which are escaped through the feed tray 114. The feed tray 115 also includes a third set of spray nozzles (not shown) configured to spray a cleaning mixture over the feed tray 115 to prevent clogging of the lignin sludge and filamentous residue present in the biomass slurry received by the feed tray 115.
[0089] The present invention discloses an improved distillation column configuration designed to optimize separation efficiency, particularly when processing challenging feedstocks containing entrained filamentous residues. The column incorporates two key innovations: a specialized arrangement of inverted V-notches and a dynamically adjustable distribution system for internal components that responds to varying feed characteristics.
[0090] The column employs inverted V-notches positioned adjacent to chimney trays, arranged in a sequential angular pattern ranging from 0° (horizontal) to 180° (diametrically opposite horizontal) in predetermined increments. This angular progression, typically implemented in 15° steps (0°, 15°, 30°... up to 180°), creates varying flow patterns that effectively entrain and remove fibrous or particulate matter from the slurry. This angular progression ensures complete entrainment and removal of filamentous residues by altering fluid dynamics, breaking inertia and preventing clogging, thereby maintaining consistent performance. The angular progression of notches also ensures that all the filmentous residue in the slurry dispersed and oriented in any direction are entrained with novel angular progression of inverted V-notches.
[0091] A critical feature of the invention is its flexible component allocation system, where the active tray area (excluding downcomer sections) can be dynamically configured with pall rings, inverted V-notches, and chimney trays in varying proportions. The system accommodates multiple operational modes: a balanced configuration with approximately 33% allocation for each component type, or customized distributions where any single component may occupy between 25% to 60% of the active area, with preferred embodiments operating within the 30% to 55% range for individual components. This adjustability is particularly maintained for the feed tray and its immediately adjacent trays (one above and one below the feed point), where feed composition variations most significantly impact separation efficiency.
[0092] The percentage allocation is precisely calibrated based on real-time assessment of feed characteristics, including but not limited to viscosity, solids content, fouling tendency, and desired separation parameters. In standard operation, the system may default to an equal 33% distribution of pall rings, V-notches, and chimney trays when processing conventional feeds. For challenging slurries with high filamentous loading, the configuration might shift toward 55% inverted V-notches to maximize solids entrainment, while high-viscosity feeds might utilize 50-55% pall rings to enhance vapor-liquid contact. The system maintains operational flexibility while ensuring that no single component falls below 25% or exceeds 60% of the active tray area in any configuration, with preferred operating ranges maintaining components between 30% and 55% allocation.
[0093] The angular V-notch arrangement prevents solids accumulation while the adjustable component distribution optimizes mass transfer efficiency across different operating conditions. Together, these features provide a distillation system that maintains high separation efficiency while reducing fouling-related downtime, offering significant advantages over conventional fixed-configuration columns.
[0094] Downstream to the feed tray 115, another feed tray 116 is provided which is having similar structure as feed tray 114 described above. However, the V-notches 201, pall ring 202 and risers 208 are placed on the tray in a mirror layout or reflected design to the tray configuration 114. The feed tray 116 includes a plurality of pall rings 202 to segregate lignin sludge from the biomass slurry when the biomass slurry 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 maximise the number of contours and crevices that cause flow of the biomass slurry to be held up, and assist segregation of the lignin sludge present in the biomass slurry.
[0095] In this manner, at least one feed tray 114 or feed tray 116 is present on both sides of the feed tray 115 to ensure maximum entrapment of the fibrous residues and high lignin content. The V-notches (203) in the feed tray efficiently trap fibers, preventing sieve tray blockages.
[0096] The feed tray 116 also includes a fourth set of spray nozzles (not shown) configured to spray a cleaning mixture over the feed tray 116 to prevent clogging of the lignin sludge present in the biomass slurry received by the feed tray 116. The pall rings 202 ensure that the lignin sludge present in the biomass slurry is stagnated and segregated from the biomass slurry. Subsequently, the set of spray nozzles may dispense the cleaning mixture over the feed tray 116 to enable collection of the stagnated lignin sludge into a sump 206 of the feed tray 116. Each feed tray 114, 116 may also include a plurality of risers 208 that allow the vapour generated by the heat exchanger 106 to escape therethrough in the vertically upward direction, and facilitate liquid-gas interaction between the biomass slurry and the vapour. The set of spray nozzles may be timer-controlled to dispense the cleaning mixture over the feed trays 114, 116 in pre-defined time intervals of 5 to 25 minutes, for example. In an exemplary embodiment, each feed tray 114, 116 may include 1 to 20 spray nozzles to direct the second cleaning mixture in the opposite direction to the fractionation flow of the biomass slurry over the feed tray 114, 116. The cleaning mixture may contain an equimolar mixture of acetic acid and methanol.
[0097] The pall rings 202 may be arranged over the feed tray 114, 116 in a staggered/random manner such that the lignin sludge contained within the biomass slurry is segregated when the biomass slurry passes over the feed trays 114, 116, and gets collected within a sump 206 of the feed trays 114, 116.
[0098] In an exemplary embodiment, the third type of feed tray 117 with only modified wiers (203) for fiber separation and lignin accumulation. Wiers (203) on plates help in enhanced lignin and fibrous biomass removal.
[0099] The sets of spray nozzles may be configured to flush the cleaning mixtures over the corresponding sieve tray 108 or the feed trays 114, 115, 116 and 117 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, 115, 116 and 117within the distillation tower 102.
[00100] 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 set of spray nozzles 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 sets of spray nozzles in response to ethanol specification disturbances caused by the clogging/choking of the sieve trays 108 and the feed trays 114.
[00101] In an exemplary embodiment, the controller is configured to manage the sets of spray nozzles 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.
[00102] 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.
[00103] The sieve trays 108 and the feed trays 114, 115, 116 and 117 may be arranged in a staggered manner relative to one another along the height of the distillation tower 102, such that the biomass slurry introduced within the distillation tower 102 by the feed entry nozzle 104 passes through each of the sieve trays 108 and the feed trays 114 to enable effective segregation of the lignin sludge and filamentous residues from the biomass slurry. In an exemplary embodiment, the feed entry nozzle 104 may be positioned such that the biomass slurry introduced within the distillation tower 102 is supplied over any or a combination of the sieve trays 108 and the feed trays 114, 115, 116 and 117 in a sequential manner.
[00104] 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.
[00105] Each of the feed trays 114, 115, 116 and 117 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, 115, 116 and 117 may include a second weir 212 to allow supply of the biomass slurry in the downstream direction only when the biomass slurry overflows through the second weir 212, while the lignin sludge gets collected in the sump 206 of the feed trays 114, 115, 116 and 117.
[00106] 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 set of spray nozzles is activated, the valve is simultaneously triggered to open the drain outlet pipe 210. This allows the washed liquid with filamentous residue and lignin sludge to flow into the settling tanks 136 and 138. In a further embodiment, a portion of the biomass slurry, which is laden with lignin sludge and filamentous residue, 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.
[00107] 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 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.
[00108] In an exemplary embodiment, the lignin-laden biomass slurry that escapes from the last tray 108/117 reaches the liquid pool at the bottom of the distillation tower 102. 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, 117, free from lignin lumps and nucleation-assisted lignin agglomerates.
[00109] FIG. 4 shows a detailed view of the feed trays 114 and 116 provided with the plurality of V-notches (201), pall rings (202) and risers (208). However, it may be appreciated that the number and configuration of these components on the tray may be varied according to requirement of the column based on the composition of the feed. Futher, the positioning of the components on the trays 114 and 116 is in mirroring position for providing maximum utility.
[00110] FIG. 5 shows a detailed view of the feed trays 115 provided with the plurality of V-notches (201) and risers (208). However, it may be appreciated that the number and configuration of these components on the tray may be varied according to requirement of the column based on the composition of the feed.
[00111] FIG. 6 shows a detailed view of the feed trays 117 provided with the plurality of V-notches (203) for fiber separation. V-notches (203) on plates help in enhanced lignin and biomass removal. The V-notches (203) in the feed tray efficiently trap fibers, preventing sieve tray blockages. However, it may be appreciated that the number and configuration of V-notches (203) on the tray may be varied according to requirement of the column based on the composition of the feed.
[00112] FIG. 7 illustrates an exemplary flow chart representation of a process 700 for producing ethanol with a biomass slurry having filamentous residue and high lignin content. The process 700 is performed by the apparatus 100 depicted in FIG. 1. The biomass slurry may contain at least 21-25% w/w lignin sludge with filamentous residues. In an embodiment, the biomass slurry may contain at least 15-20% w/w lignin sludge with fibrous residues.
[00113] The process 700 includes a step 702 of receiving, by the feed entry nozzle 104 of the distillation tower 102, the biomass slurry at a pre-defined rate. The biomass slurry is supplied to the at least one sieve tray 108 having the perforations 110 to enable passage for the vapour to pass therethrough. The process 700 also includes, at step 704, supplying the biomass slurry to at least one sieve tray (108) having a plurality of perforations (110) to enable passage for the vapour to pass therethrough; the process 700 also includes, at step 706, passing the ethanol broth through at least one feed tray with downward v-notches (201) to trap filamentous material and micro-lignin particles. At the step 708, the process includes directing the ethanol broth through a feed tray comprising a packed bed with pall rings (202) and v-notches (201) to further separate lignin and fibrous residues;
[00114] The process 700 also includes, at step 710, boiling, by the heat exchanger 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. The pall rings 202 of the at least one feed tray 114 positioned downstream of the at least one sieve tray 108, entrap and segregate lignin sludge from the biomass slurry. At 712 process includes allowing, by the risers 208 of the at least one feed tray 114, the vapour generated by the heat exchanger 106 to escape therethrough in the vertically upward direction.
[00115] The process 700 further includes a step 714 of regulating, by a controller of the apparatus 100, 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 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 712 of regulating may include controlling actuation of the first set of spray nozzles 112 and the second set of spray nozzles 204 based on pre-determined washing cycles. The process 700 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. The process 700 may further include 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.
[00116] The process 700 may include a step 716 of injecting an equimolar mixture of methanol and acetic acid through a spray nozzle system to break down lignin nucleation sites and prevent agglomeration;
[00117] The process 700 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 process 700 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 process 700 may also include supplying a liquid output from the centrifuge 140 to the heat exchanger 106 to facilitate generation of the vapour. The process 700 may include extracting, by the outlet nozzle 120 of the distillation tower 102, purified ethanol from the biomass slurry.
[00118] The process 700 may include regulating, by the first weirs of the sieve trays 108, flow of the biomass slurry such that the biomass slurry is supplied in the downstream direction only when the biomass slurry overflows through the first weirs. The process 700 may further include regulating, by the second weirs 212 of the feed trays 114, flow of the biomass slurry such that the biomass slurry is supplied in the downstream direction only when the biomass slurry overflows through the second weirs 212.
[00119] In the process the equimolar mixture of methanol and acetic acid injected by the spray nozzle system comprises 3% to 6% methanol and 3% to 6% acetic acid by volume.
[00120] In the process 700, the automated ratio controller adjusts the spray nozzle system activation based on a feedback mechanism triggered by an increase in vapor velocity due to sieve tray clogging.
[00121] In the process 700, the lignin-laden slurry removed by the automated sludge removal system is settled in a settling tank for 15 minutes to 4 hours before being sent to a centrifuge for further separation.
[00122] In the process 700, the clarified liquid from the centrifuge is recycled back to the reboiler pool liquid for reuse in the spray nozzle system.
[00123] In the process 700, the feed tray with downward V-notches is designed to handle a feed composition comprising 21% to 25% lignin by weight.
[00124] In the process 700, the process comprises separating ethanol from undesired components in a stripping section.
[00125] In the process 700, the stripping section operates at a temperature range of 78°C to 85°C to separate ethanol from water and other impurities.
[00126] In the process 700, comprising maintaining ethanol purity in a rectification section to achieve 95.5 mole% ethanol in compliance with IS15464:2004 standards.
[00127] In the process 700, the rectification section operates at a temperature range of 78°C to 82°C to maintain ethanol purity at 95.5 mole%.
[00128] With the apparatus 100 and the process 700 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.
[00129] Thus, the apparatus 100 and the process 700 of the present disclosure enable the efficient processing of biomass slurries & ethanol broth with filamentous residues and high lignin content to produce high yields of ethanol. By reducing lignin-related barriers, the process 700 enhances enzymatic hydrolysis and fermentation efficiency, leading to improved ethanol production. The apparatus 100 and the process 700 minimize the need for excessive energy input, harsh chemicals, and enzymes, thereby reducing environmental impact and operational costs compared to conventional ethanol production techniques.
[00130] While the present invention has been described with reference to bamboo feedstock, it is to be understood that the distillation system and process disclosed herein are not limited to bamboo alone. Other feedstocks with high fiber and lignin content, may also be processed using the disclosed system. Furthermore, slurries containing filamentous residues and high-lignin-content materials, either individually or in combination, can be effectively utilized for bioethanol production. The system and process of the present invention are capable of enhancing ethanol purity and yield, irrespective of the specific high-lignin biomass feedstock employed. Accordingly, the scope of the invention should be determined by the appended claims rather than by the examples provided herein.
[00131] 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
[00132] The present disclosure provides an apparatus and a process for efficiently processing biomass slurries & ethanol broth with filamentous residues and high lignin content, enabling high yields of ethanol.
[00133] The present disclosure provides a process for producing ethanol from biomass slurries & ethanol broth without the need for excessive energy input or harsh chemicals. This reduces the environmental impact and lowers operational costs associated with conventional processes that rely on aggressive chemicals and energy-intensive processs.
[00134] The present disclosure provides a Column Internals Design for 2G Ethanol Bio-Refinery with Filamentous-Residues & High-Lignin Laden Bamboo Feed. This invention aims to address challenges associated with filamentous material and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency. The system introduces a feed tray with only downward V-notches, along with a chimney tray featuring a combination of packed bed and V-notches on one plate above and one plate below the tray. These elements work together to enhance phase separation, optimize ethanol recovery, and prevent clogging
[00135] The present disclosure provides an apparatus and process for the production of ethanol while reducing energy consumption, chemical use,. This makes the apparatus economically viable and competitive for large-scale commercial ethanol production.
[00136] The present disclosure provides a process that promotes environmentally sustainable bioethanol production by reducing the need for harsh chemicals, lowering energy consumption, and minimizing toxic by-product generation. This contributes to the sustainability of biofuels as a renewable energy source, making the process eco-friendly.
[00137] The present disclosure provides an apparatus designed to be adaptable to a wide range of biomass feedstocks with low to moderate lignin content. This flexibility allows the apparatus to process different types of biomass, making it scalable and versatile for various industrial applications and feedstock types.
[00138] The present disclosure provides an apparatus and process for producing ethanol that are easily scalable for large-scale bioethanol production, maintaining high efficiency and low operational costs. The scalability of the apparatus helps meet the increasing global demand for biofuels while maintaining efficient production processes.
[00139] The present invention offers significant advantages over conventional distillation systems by enhancing efficiency, cost-effectiveness, and sustainability. Its innovative design ensures superior filamentous biomass removal through inverted V-notches, pall rings and multiple wier arrangement across sieves, preventing sieve tray blockages and enabling continuous tower operation with minimal shutdowns and maintenance. The system achieves high ethanol purity of 95.5 mole% in compliance with IS15464:2004 while optimizing energy utilization by reducing heat loss and cleaning-related energy consumption. Economic feasibility is improved through the recovery of methanol and acetic acid, and an automated cleaning mechanism with a ratio controller enables dynamic process adjustments without manual intervention. Additionally, the system supports India's Net Zero 2070 goal by promoting sustainable biofuel production and is scalable for both small and large industrial bio-refineries.
, Claims:1. A distillation column system for separating ethanol from a lignin-laden ethanol broth derived from high-lignin feedstock with filamentous residues, the system comprising:
- a feed entry nozzle to introduce a lignin-laden ethanol broth with filamentous residues into the column;
- at least one sieve tray having a plurality of perforations to enable passage of the vapour therethrough, and a first set of spray nozzles configured to spray a cleaning mixture over the sieve tray to prevent clogging by lignin sludge;
- at least one feed tray positioned downstream of the sieve tray to trap filamentous material and micro-lignin particles from the ethanol broth, the feed tray comprising:
• a plurality of V-notches to trap filamentous residues;
• a plurality of pall rings arranged in a random packing arrangement to segregate lignin sludge from the biomass slurry;
• risers to allow the vapor to escape upwardly; and
• a second set of spray nozzles configured to spray the cleaning mixture over the feed tray to collect the lignin sludge into a sump;
- at least one feed tray comprising a combination of V-notches and risers to enhance solid-liquid separation of lignin and fibrous residues;
- a heat exchanger positioned at a bottom of the distillation unit to boil a liquid and generate vapour traversing upwardly within the distillation unit;
- an automated sludge removal system configured to continuously extract micro-lignin and fibrous residues from the distillation column;
- an automated ratio controller configured to adjust the activation of the spray nozzle system based on ethanol purity and feed composition, wherein the spray nozzle system is configured to inject an equimolar mixture of methanol and acetic acid to break down lignin nucleation sites and prevent agglomeration.
2. The distillation column as claimed in claim 1, wherein the feed tray is constructed from SS-316 stainless steel to withstand corrosive and abrasive conditions caused by C-5 and C-6 sugars.

3. The distillation column as claimed in claim 1, wherein the spray nozzle system comprises 1 to 20 spray nozzles per sieve tray in particular 4 to 12 spray nozzles per sieve tray.

4. The distillation column as claimed in claim 1, wherein the spray nozzle system is configured to operate in co-current, counter-current, and cross-flow directions to dislodge and wash accumulated lignin from the sieve trays.

5. The distillation column as claimed in claim 1, wherein the automated ratio controller is configured to activate the spray nozzle system at intervals of 5 to 25 minutes particularly 10 to 15 minutes.

6. The distillation column as claimed in claim 6, wherein a rectification section is provided for maintaining ethanol purity in compliance with IS15464:2004 standards.

7. The distillation column as claimed in claim 1, further comprising a drain outlet pipe positioned before the outlet downcomer, the drain outlet pipe configured to remove lignin-laden slurry from the distillation column.

8. The distillation column as claimed in claim 8, wherein the drain outlet pipe is controlled by an actuated valve synchronized with the spray nozzle system.

9. The distillation column as claimed in claim 1, wherein the packed bed in the chimney tray comprises random packing to capture suspended lignin and prevent entrainment into vapour streams.

10. The distillation column as claimed in claim 1, wherein the inverted V-notches are provided besides the chimney tray and the V-notches are arranged sequentially at different angles from 0 degree to 180 degree to facilitate complete entrainment of filamentous residue from slurry.

11. The distillation column as claimed in claim 1, the percentage allocation of pall rings, inverted v-notches and chimney trays 25 % to 60 % of active tray area for any one allocation depeding upon the feed.

12. The distillation column as claimed in claim 1, the percentage allocation of pall rings, inverted v-notches and chimney trays 30 % to 55 % of active tray area for any one allocation depeding upon the feed.

13. The distillation column as claimed in claim 1, the percentage allocation of pall rings, inverted v-notches and chimney trays 33% each of active tray area for any one allocation depeding upon the feed.

14. A process for distilling ethanol from a lignin-laden ethanol broth derived from high-lignin laden feedstock with filamentous residues, the process comprising:
- introducing the lignin-laden ethanol broth with filamentous residues into a distillation column through a feed entry nozzle at a predefined rate;
- passing the biomass slurry through at least one sieve tray having perforations to enable vapor passage, while spraying a first cleaning mixture to prevent lignin sludge clogging;
- directing the biomass slurry through at least one feed tray placed in downward direction of the sieve tray, the feed tray comprising V-notches to trap filamentous residues, pall rings to segregate lignin sludge, and risers to allow vapor escape, while spraying a cleaning mixture to collect the lignin sludge into a sump;
- boiling a liquid at a bottom of the distillation unit to generate vapour traversing upwardly;
- regulating the spraying of the cleaning mixtures based on pre-determined washing cycles, ethanol purity parameters and feed composition using an automated ratio controller;
- injecting a cleaning mixture of methanol and acetic acid through a spray nozzle system to break down lignin nucleation sites and prevent agglomeration;
- continuously removing micro-lignin and fibrous residues through an automated sludge removal system from the sump via a drain outlet pipe;
- extracting purified ethanol from the distillation unit.

15. The process as claimed in claim 13, wherein the cleaning mixture comprises an equimolar mixture of methanol and acetic acid injected by the spray nozzle system comprises 3% to 6% methanol and 3% to 6% acetic acid by volume.

16. The process as claimed in claim 13, wherein the wherein the cleaning mixture comprises non equimolar mixture of methanol and acetic acid injected by the spray nozzle system.

17. The process as claimed in claim 13, wherein the automated ratio controller adjusts the spray nozzle system activation based on a feedback mechanism triggered by an increase in vapor velocity due to sieve tray clogging.

18. The process as claimed in claim 13, wherein the lignin-laden slurry removed by the automated sludge removal system is settled in a settling tank for 15 minutes to 4 hours before being sent to a centrifuge for further separation.

19. The process as claimed in claim 13, wherein the clarified liquid from the centrifuge is recycled back to the reboiler pool liquid for reuse in the spray nozzle system.

20. The process as claimed in claim 13, wherein the feed tray with downward V-notches is designed to handle a feed composition comprising 21% to 25% lignin by weight.

21. The process as claimed in claim 13, wherein the process comprises separating ethanol from undesired components in a stripping section.

22. The process as claimed in claim 20, wherein the stripping section operates at a temperature range of 78°C to 85°C to separate ethanol from water and other impurities.

23. The process as claimed in claim 13, comprising maintaining ethanol purity in a rectification section to achieve 95.5 mole% ethanol in compliance with IS15464:2004 standards.

24. The process as claimed in claim 22, wherein the rectification section operates at a temperature range of 78°C to 82°C to maintain ethanol purity at 95.5 mole%.