Description:TECHNICAL FIELD
[0001] The present disclosure relates generally to the technical field of ethanol production plants. In particular, it pertains to an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues. More specifically, it pertains to an apparatus for second generation (2G) ethanol bio-refinery with inorganic-needle-residues, and high-lignin laden coconut shell-frond-husk-pith feed to address the challenges associated with the inorganic-needle-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The production of second-generation (2G) ethanol from lignocellulosic biomass, coconut shell-frond-husk-pith and other high-lignin materials, has garnered significant interest as a renewable and sustainable energy source. These biomass feedstocks, however, present numerous challenges during the distillation process due to their high fiber content and the presence of inorganic needle residues. The inherent characteristics of these feedstocks significantly impact the efficiency of the distillation process, leading to operational difficulties, increased downtime, and reduced ethanol yields.
[0004] One of the primary challenges in distilling 2G ethanol from high-lignin biomass is the severe clogging of sieve trays and internal components of distillation columns caused by long, fibrous particles. These particles can accumulate in various sections of the column, leading to blockages that reduce the efficiency of the distillation process and often require frequent manual cleaning and maintenance. Additionally, the fibrous particles disrupt the vapour-liquid mass transfer, which is critical for effective separation and ethanol recovery. The inconsistency in mass transfer results in reduced ethanol purity and overall yield, increasing the cost of production and decreasing the economic viability of using lignocellulosic biomass as a feedstock for bioethanol production.
[0005] Further, the presence of inorganic needle-like residues further exacerbates these issues. These residues are difficult to separate from the ethanol and can accumulate in the stripping section of the distillation column, causing operational disruptions and further increasing maintenance requirements. This accumulation of biomass in the stripping section can lead to tower flooding, inefficient operation, and a significant reduction in the capacity of the distillation column.
[0006] Current distillation technologies, which typically rely on conventional sieve trays, struggle to address these challenges effectively. While some improvements have been made through the use of specialized trays or packing materials, these approaches have not fully resolved the issues associated with fiber removal, phase separation, and efficient distillation in the presence of high-lignin biomass feedstocks.
[0007] In view thereof, there is need to modify design of internals of the distillation column to separate inorganic-needle residues from the ethanol, and to ensure effective phase separation, residue attraction, and uninterrupted distillation process.
[0008] There is, therefore, a need to overcome the above-mentioned drawbacks, shortcomings, and limitations associated with the existing design of the ethanol production plants, by providing an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues.

OBJECTS OF THE PRESENT DISCLOSURE
[0009] An object of the present disclosure relates, in general, to the field of distillation columns, and more specifically, relates to an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues.
[0010] An object of the present disclosure is to provide an apparatus for second generation (2G) ethanol bio-refinery with inorganic-needle-residues, and high-lignin laden coconut shell-frond-husk-pith feed to address the challenges associated with the inorganic-needle-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0011] An object of the present disclosure is to minimize the accumulation of inorganic-needle residues on sieve trays, feed trays, column internals, and heat and mass transfer/exchange surfaces of the apparatus, thereby reducing the need for frequent cleaning, downtime, and maintenance costs associated with the distillation column of the apparatus.
[0012] Another object of the present disclosure is to optimize phase separation within the distillation process by ensuring the proper distribution and trapping of silica and inorganic-needle residues, improving ethanol purity and distillation efficiency.
[0013] Another object of the present disclosure is to provide a solution that maximizes the recovery of ethanol from the fermentation broth, ensuring that the ethanol produced meets or exceeds fuel-grade specifications while minimizing the loss of ethanol due to residue interference.
[0014] Another object of the present disclosure is to increase ethanol recovery efficiency by preventing the entry of solid impurities into the rectification and stripping sections, resulting in higher ethanol yields and minimal impurity contamination.
[0015] Yet another object of the present disclosure is to design an apparatus that captures and retains rigid, sharp, needle-shaped particles, thereby minimizing erosion and mechanical wear.
[0016] Still yet another object of the present disclosure is to extend the operational lifespan of the distillation column by improving filtration efficiency, reducing wear and tear on column internals.

SUMMARY
[0017] The present disclosure relates, in general, to the field of ethanol production plants. In particular, it pertains to an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues. More specifically, it pertains to an apparatus for second generation (2G) ethanol bio-refinery with inorganic-needle residues, and high-lignin laden coconut shell-frond-husk-pith feed to address the challenges associated with the inorganic-needle residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0018] According to an aspect, the present disclosure pertains to an apparatus for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues. 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. Further, the apparatus 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 lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray.
[0019] In addition, the apparatus 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 mesh screens to trap the inorganic-needle residues from the biomass slurry and ethanol broth flowing in a radial direction over the at least one feed tray of the distillation unit. Further, the at least one feed tray includes a plurality of risers configured to allow the vapour generated by the heat exchanger/reboiler to escape therethrough in the vertically upward direction.
[0020] In one or more embodiments, the at least one feed tray may include a plurality of pall rings arranged in a random packing arrangement to facilitate removal of the lignin sludge from the biomass slurry and ethanol broth. Further, the at least one feed tray may include 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 and/or the inorganic-needle residues over the at least one feed tray, and enable collection of the lignin sludge and/or the inorganic-needle residues into a sump of the at least one feed tray.
[0021] In one or more embodiments, 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 of the at least one feed tray.
[0022] In one or more embodiments, the at least one feed tray may include a first feed tray, and at least two second feed trays. The first feed tray may be configured with an arrangement of the plurality of mesh screens, and the plurality of risers in a first configuration The at least two second feed trays may be configured with an arrangement of the plurality of mesh screens, the second set of spray nozzles, the plurality of pall rings, and the plurality of rises in a second configuration. The first feed tray and the at least two second feed trays are arranged in a staggered manner relative to one another along a height of the distillation unit.
[0023] In one or more embodiments, the at least two second feed trays may be configured such that one of the at least two second feed trays is positioned downstream of the first feed tray, and other second feed tray among the at least two second feed trays may be configured above the first feed tray within the distillation unit.
[0024] In one or more embodiments, the plurality of mesh screens may be configured over a moving portion of the at least one feed tray in a meandering manner creating a tortuous path, where the moving portion may rotate about a hinge point in a downward direction, due to weight of the collected inorganic-needle residues thereby allowing flow of the inorganic-needle residues to the sump.
[0025] In one or more embodiments, the distillation unit may include one or more sensors configured with the moving portion. When the moving portion rotates about the hinge point, the one or more sensors may sense the rotation of the moving portion, and may transmit an actuation signal to a controller, based on the sensed rotation.
[0026] In one or more embodiments, 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.
[0027] In one or more embodiments, 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.
[0028] In one or more embodiments, the distillation unit may include the controller configured to monitor clogging of the lignin sludge and/or the inorganic-needle residues received by the any of the at least one sieve tray and the at least one feed tray. The controller may also be configured to receive the actuation signal from the one or more sensors to actuate the first set of spray nozzles and the second set of spray nozzles. Further, the controller may 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.
[0029] In one or more embodiments, the first cleaning mixture may include equimolar mixture of acetic acid and methanol.
[0030] In one or more embodiments, the second cleaning mixture may include non-equimolar mixture of acetic acid and methanol.
[0031] In one or more embodiments, the biomass slurry and ethanol broth may contain about 21-25% Weight/Weight (w/w) lignin sludge.
[0032] In one or more embodiments, 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 the height of the distillation unit.
[0033] In one or more embodiments, the generated vapour by the heat exchanger/reboiler may enter the distillation unit through a vapour inlet nozzle configured near a first end of the distillation unit.
[0034] In one or more embodiments, the at least one sieve tray may be configured downstream of the second feed tray, which second feed tray is positioned downstream of the first feed tray. The at least one sieve tray may include a set of protrusions or upward notches arranged in a staggered manner such that the set of protrusions or upward notches may facilitate collection of any remaining lignin or inorganic-needle residues agglomerates from purified ethanol by hindering the flow of the purified ethanol in the radial direction which results in increased residence time for the purified ethanol over the at least one sieve tray.
[0035] In one or more embodiments, the distillation unit may include a feed entry nozzle configured to supply the biomass slurry and ethanol broth to any of the at least one sieve tray and the at least one feed tray at a pre-defined rate.
[0036] In one or more embodiments, the distillation unit may include one or more settling tanks configured to receive the inorganic-needle residues and/or the lignin sludge collected in the sump of the at least one feed tray.
[0037] In one or more embodiments, the distillation unit may include a centrifuge configured to separate the inorganic-needle residues and/or the lignin sludge suspended in the biomass slurry and ethanol broth, and supply the separated inorganic-needle residues and/or the lignin sludge to the one or more settling tanks.
[0038] In one or more embodiments, the distillation unit may include an outlet nozzle configured to extract the purified ethanol.
[0039] In one or more embodiments, the at least one sieve tray may include a first weir or 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 or downcomer.
[0040] In one or more embodiments, the at least one feed tray may include a second weir or 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 or downcomer. In one or more embodiments, each of the plurality of mesh screens may include a filtration material selected from any one of: stainless steel, corrosion-resistant alloys, or synthetic polymers.
[0041] In one or more embodiments, the mesh screen may have a pore size ranging from 10 microns to 120 microns to trap the inorganic-needle residues present in the biomass slurry and ethanol broth.
[0042] In one or more embodiments, the mesh screen may have meshes arranged in such a manner that their orientation from left to right varies from 0 degree to 45 degree in upward and downward (0 degree to -45 degree) direction from central axis of mesh.
[0043] In one or more embodiments, the mesh with varying angles may cross intersect with each other to form a cross linked web to entangle and collect needles of varying size, nominal diameter and width.
[0044] In one or more embodiments, the mesh screen may be formed of at least one of: a woven structure, or a braided structure to increase strength and resistance to mechanical wear.
[0045] In another aspect, the present disclosure pertains to a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues. The method includes receiving, by a feed entry nozzle 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. Further, the method includes supplying 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. Furthermore, the method includes segregating, by a plurality of mesh screens of at least one feed tray positioned downstream of the at least one sieve tray, the inorganic-needle residues from the biomass slurry and ethanol broth. The method also includes 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. Moreover, the method 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 lignin sludge present in the biomass slurry and ethanol broth 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 inorganic-needle residues into a sump of the at least one feed tray.
[0046] In one or more embodiments, the method may include the step of segregating, by a plurality of pall rings configured over the at least one sieve tray, the lignin sludge from the biomass slurry and ethanol broth. Further, the method may include the step of regulating, by the controller, actuation of the second set of spray nozzles to control dispensing of the second cleaning mixture over the at least one feed tray to enable collection of the lignin sludge into the sump of the at least one feed tray.
[0047] In one or more embodiments, 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.
[0048] In one or more embodiments, the biomass slurry and ethanol broth may contain at least 21-25% Weight/Weight (w/w) lignin sludge.
[0049] In one or more embodiments, the method may include separating, by a centrifuge of the distillation unit, the lignin sludge and/ or inorganic-needle residues collected in the sump of the at least one feed tray. Further, the method may include supplying the separated lignin sludge and/or inorganic-needle residues to one or more settling tanks.
[0050] In one or more embodiments, the method may include extracting, by an outlet nozzle of the distillation unit, purified ethanol from the biomass slurry and ethanol broth.
[0051] 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
[0052] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0053] FIG. 1 illustrates an exemplary schematic representation of an apparatus for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, in accordance with one or more embodiments of the present disclosure.
[0054] FIG. 2 illustrates an arrangement of multiple feed trays along a height of a distillation unit of the apparatus of FIG. 1, in accordance with one or more embodiments of the present disclosure.
[0055] FIG. 3 illustrates an exemplary flow chart representation of a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION
[0056] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0057] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0058] The present disclosure relates, in general, to the field of distillation columns, and more specifically, relates to a distillation column for second generation (2G) ethanol bio-refinery with inorganic-needle-residues, and high-lignin laden coconut shell-frond-husk-pith feed to address the challenges associated with the inorganic-needle-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0059] The present invention provides a solution to a spectrum of engineering challenges in distillation columns/towers used for bio-ethanol distillation, with feedstock having high lignin content with inorganic-needle residues. In addition to ethanol, acetic acid, fusel oil, and technical oil 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 at 15.6/15.6°C minimum (excluding denaturant), a relative density of 0.7961 (max), and a flashpoint of 16.6°C. 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.
[0060] In addition, the presence of inorganic-needle residues in the distillation process can cause severe operational issues, including clogging of sieve trays, internals, and the stripping section, which disrupts vapour-liquid mass transfer and reduces ethanol recovery efficiency. These sharp, rigid residues can damage equipment, leading to increased wear and tear, requiring frequent maintenance and repairs, resulting in higher downtime and operational costs. Moreover, they interfere with the distillation process, lowering ethanol purity and yield, while also contributing to environmental concerns by generating additional waste. The accumulation of these residues reduces operational stability, making it difficult to scale the process or adapt to different biomass feedstocks, ultimately hindering the efficiency, cost-effectiveness, and sustainability of ethanol production.
[0061] FIG. 1 illustrates an exemplary schematic representation of an apparatus for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, in accordance with one or more embodiments of the present disclosure. The apparatus 100 includes a distillation unit 102 (also referred as “distillation tower 102” or “distillation column 102” herein) configured to receive and process the biomass slurry and ethanol broth to reduce lignin content thereof. The biomass slurry and ethanol broth can include coconut shells, coconut husks, coconut fronds, coconut pith, and the like, which contain about 21-25% w/w lignin sludge, which produces inorganic-needle residues when used in the biomass slurry and ethanol broth production. In some embodiments, the biomass slurry and ethanol broth can include Bagasse, rice husk, wheat straw, corn stovers, wood chips, switchgrass, and the like, which also produces inorganic-needle residues when used in the biomass slurry and ethanol broth production. These inorganic-needle residues, particularly those rich in silica, are problematic in distillation processes due to their sharp, rigid nature, which can cause equipment wear, clogging, and operational disruptions.
[0062] The distillation column 102 can be made of material such as but not limited to stainless steel, carbon steel, titanium, nickel alloys, copper, aluminium, and the like, depending upon its application areas. The distillation column 102 can be selected from any one of: continuous distillation columns, batch distillation columns, fractional distillation columns, and the like, without any limitations, whatsoever. In a preferred embodiment, the distillation column 102 can be selected as the fractional columns such as sieve tray distillation column.
[0001] In an embodiment, the distillation column 102 includes a feed entry nozzle 104 that receives the biomass slurry and ethanol broth containing the high lignin-laden ethanol broth, and supplies the biomass slurry and ethanol broth within the distillation column 102 for processing. The feed entry nozzle 104 can be selected from but not limited to axial feed nozzles, venture nozzles, radial nozzles, self-cleaning nozzle, and the like. In a preferred embodiment, the feed entry nozzle 104 can be radial nozzle which are configured at a circumference of the distillation column 102. The distillation column 102 includes a heat exchanger 106, such as a reboiler, configured to boil a liquid at a bottom of the distillation column 102 to generate vapour traversing in a vertically upward direction within the distillation column 102. The distillation column 102 also includes at least one sieve tray such as 108-1, 108-2, 108-3, …..108N (collectively or individually referred as “sieve trays 108” or “sieve tray 108” herein) arranged along a height of the distillation column 102. The sieve tray 108 includes 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 the biomass slurry and ethanol broth received by the at least one sieve tray 108. The first set of spray nozzles 112 can be timer-controlled to dispense the first cleaning mixture over the at least one sieve tray 108 in pre-defined time intervals of 5 to 25 minutes, for instance. In an exemplary embodiment, each sieve tray 108 can include 1 to 20 spray nozzles 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 set of spray nozzles 112 can be configured along a periphery of the at least one sieve tray 108. The first cleaning mixture can include equimolar mixture of acetic acid and methanol. In some embodiments, the first cleaning mixture can include side stream from the reboiler 106 mixed with equimolar mixture of 3% -6% methanol and acetic acid. The sieve tray 108 can include a first weir 214 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 214.
[0002] In addition, the distillation column 102 includes one or more feed trays such as 114-1, 114-2, … 114-N (also referred to as “feed tray 114” herein) arranged along the height of the distillation column 102. At least one feed tray 114 can 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 tray 114 can be made of material such as stainless steel, carbon steel, nickel alloy, titanium, glass-lined steel, and the like, without any limitations. In a preferred embodiment, the feed tray 114 can 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.
[0063] As illustrated in FIG.1, the distillation column 102 of the proposed apparatus 100 is designed with several key features that work together to ensure efficient ethanol recovery by efficient distillation process. A liquid inlet nozzle 116 is configured to introduce the liquid feed into the distillation column 102, directing it to the reboiler 106. The reboiler 106 heats the liquid supplied into the distillation column 102 through the liquid inlet nozzle 116, to generate the vapour that ascends vertically within the distillation column 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 column 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.
[0064] The distillation column 102 can 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 column 102 and into the surrounding ambient environment, where it can undergo further processing, such as condensation or phase separation. Additionally, the distillation column 102 can be equipped with a vapour inlet nozzle that facilitates entry of the vapour generated by the reboiler 106 into the distillation column 102, helping maintain the necessary vapour-liquid equilibrium for effective separation. A liquid outlet nozzle positioned at the bottom of the distillation column 102 allows the liquid from a liquid pool located at the bottom of the distillation column 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 column 102 can be calibrated 10% higher than conventional distillation columns.
[0065] The distillation column 102 can 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 column 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 can 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.
[0066] The distillation column 102 can 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 128, 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.
[0067] For handling heavier or more viscous liquids that can accumulate at the bottom of the distillation column 102, a heavy product pump 132 is incorporated. The heavy product pump 132 is responsible for transferring these liquid products, which can be high in temperature or viscosity, from the bottom of the distillation column 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 column 102. The reflux pump 134 helps improve separation efficiency by sending the condensed liquid back to the distillation column 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 column 102.
[0068] Referring to FIG. 2, each feed tray 114 includes a plurality of mesh screens 202 (collectively referred as “mesh screens 202” hereinafter) to remove the inorganic-needle residues from the biomass slurry and ethanol broth flowing in a radial direction over the feed tray 114 of the distillation unit 102. Each of the plurality of mesh screens 202 can include a filtration material selected from any one of but not limited to: stainless steel, corrosion-resistant alloys, or synthetic polymers. The filtration material can have a heat resistance properties capable of withstanding temperatures up to 400°C without significant degradation. In ethanol distillation processes, heat resistance is critical. Thus, the material of the mesh screen 202 can be selected such that it can perform effectively at high temperatures without degrading or losing structural integrity, which is important in maintaining stable filtration during distillation. Further, the mesh screen 202 can have a pore size ranging from 10 microns to 120 microns to trap the inorganic-needle residues present in the biomass slurry and ethanol broth. The mesh screen 202 can be formed of at least one of: a woven structure, or a braided structure, without limitations, to increase strength and resistance to mechanical wear.
[0069] The mesh screens 202 can be configured over a moving portion 220 of the feed tray 114 in a meandering manner creating a tortuous path, where the moving portion 220 rotates about a hinge point in a downward direction, due to weight of the collected inorganic-needle residues thereby allowing flow of the inorganic-needle residues to a sump 208.
[0070] Each feed tray 114 can also include a plurality of risers or chimneys 210 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 ethanol broth and the vapour.
[0071] In an embodiment, each of the feed tray 114 can include a plurality of pall rings 204 (collectively referred as “pall rings 204” hereinafter) arranged in a random packing arrangement to facilitate removal of the lignin sludge from the biomass slurry and ethanol broth. The pall rings 204 can be formed of hollow-cylindrical structure made of materials such as but not limited to metals, plastics, ceramics, and the like. A plurality of openings can be provided over surface of the pall rings 204 to facilitate a large surface area for contact between the liquid and vapour phases, thereby facilitating efficient mass transfer. The pall rings 204 can be designed to minimize the formation 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. The pall rings 204 can be arranged on the at least one feed tray 114 in a random packing arrangement to facilitate collection of the lignin sludge into the sump 208 of the at least one feed tray 114.
[0072] The at least one feed tray 114 can also include a second set of spray nozzles 206 configured to spray a second cleaning mixture over the at least one feed tray 114 to prevent clogging of the lignin sludge to the pall rings 204 of the feed tray 114, and enable collection of the lignin sludge and/or the inorganic-needle residues into the sump 208 of the feed tray 114. The pall rings 204 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 206 can dispense the second cleaning mixture over the feed tray 114 to enable collection of the stagnated lignin sludge and/or the inorganic-needle residues into the sump 208 of the feed tray 114. The second set of spray nozzles 206 can 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 can include 1 to 20 spray nozzles 206 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 can contain a non-equimolar mixture of acetic acid and methanol.
[0073] In an embodiment, the first and second sets of spray nozzles 112, 206 can 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, the inorganic-needle residues, or nucleation sites on the sieve tray 108 or the feed tray 114 within the distillation column 102. The apparatus 100 can 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.
[0074] In an embodiment, the at least one feed tray 114 can include a first feed tray 114-1 with an arrangement of the plurality of mesh screens 202, and the plurality of risers 210 in a first configuration, and at least two second feed trays 114-2a, 114-2b with an arrangement of the plurality of mesh screens 202, the plurality of pall rings 204, the second set of spray nozzles 206, and the plurality of risers 210 in a second configuration that is different from the first configuration. The first feed tray 114-1 and the at least two second feed trays 114-2a, 114-2b can be arranged in a staggered manner relative to one another along the height of the distillation column 102. The at least two second feed trays 114-2a, 114-2b can be configured such that one of the at least two second feed tray 114-2a can be positioned downstream of the first feed tray, and other second feed tray 114-2b among the at least two second feed tray can be configured above the first feed tray 114-1 within the distillation column 102.
[0075] The distillation column 102 can include one or more sensors configured with the moving portion 220, wherein when the moving portion 220 rotates about the hinge point, the one or more sensors can sense the rotation of the moving portion 220, and can transmit an actuation signal to a controller. Further, the distillation column 102 can include the controller configured to monitor clogging of the lignin sludge and/or the inorganic-needle residues received by the any of the at least one sieve tray 108 and the at least one feed tray 114. The controller can also be configured to receive the actuation signal from the one or more sensors to actuate the first set of spray nozzles 112 and the second set of spray nozzles 206. In addition, the controller can be configured to control actuation of the first set of spray nozzles 112 and the second set of spray nozzles 206 based on pre-determined washing cycles, and one or more parameters pertaining to purity of the ethanol to be produced. The controller can also be configured to actuate the first and second sets of spray nozzles 112, 206 in response to ethanol specification disturbances caused by the clogging/choking of the sieve trays 108 and the feed trays 114.
[0076] In an exemplary embodiment, the controller is configured to manage the first and second sets of spray nozzles 112, 206 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.
[0077] The controller can be implemented using a variety of hardware and/or software configurations to achieve the desired functionality. It can include microcontrollers, relays, switches, gates, and specialized hardware components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and electrically erasable programmable read-only memories (EEPROMs). Additionally, the controller may incorporate memory elements like non-volatile random access memory (RAM) or read-only memory (ROM) as part of its architecture. Alternatively, the controller may be fully software-based, running either as part of an operating system or as a dedicated application on a computing device. The controller can be connected to the first and second sets of spray nozzles 112, 206 via wired or wireless communication methods, depending on requirements and configuration of the apparatus 100. This flexible design allows for scalability and adaptability in various applications.
[0078] In an embodiment, the at least one sieve tray 108 can be configured downstream of the second feed tray 114-2a, which second feed tray 114-2a can be positioned downstream of the first feed tray 114-1. The at least one sieve tray 108 can include a set of protrusions/upward notches 218 arranged in a staggered manner to facilitate collection of any remaining lignin or inorganic-needle residues agglomerates from purified ethanol or nucleation sites by hindering the flow of the purified ethanol in the radial direction which results in increased residence time for the purified ethanol over the at least one sieve tray 108. The set of protrusions/upward notches 218 can be selected from but not limited to helical protrusions/upward notches, triangular notches, rectangular notches or ridges, waffle protrusions/upward notches, and the like. In a preferred embodiment, the protrusions/upward notches 218 can be the triangular notches.
[0079] The sieve trays 108 and the feed trays 114 can be arranged in a staggered manner relative to one another along the height of the distillation column 102, such that the biomass slurry and ethanol broth introduced within the distillation column 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/or the inorganic-needle residues from the biomass slurry and ethanol broth.
[0080] The distillation column 102 can include one or more settling tanks 136, 138 including a primary settling tank 136 and a secondary settling tank 138 configured to receive the lignin sludge and/ or the inorganic-needle residues collected in the sumps 208 of each of the feed trays 114. The secondary settling tank 138 can be an alternate outlet route for collection of the first and second cleaning mixtures and the lignin sludge and/or the inorganic-needle residues received from the sumps 208 of the feed trays 114. The distillation column 102 can also include a centrifuge 140 configured to separate residual sludge from the lignin sludge and/or the inorganic-needle residues received by the primary and secondary settling tanks 136, 138. A settling tank pump 142 can 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 and/or the inorganic-needle residues from the collected fluid. A liquid output from the centrifuge 140 can be supplied to the reboiler 106, through a pump, to generate the vapour that moves in the vertically upward direction within the distillation column 102. The centrifuge 140 can include a drain outlet 140-1 to enable drainage of the liquid sludge.
[0081] Each of the feed trays 114 can include a drain outlet pipe 212, as shown in FIG. 2, positioned at the sump 208 to facilitate removal of the collected lignin sludge and/or inorganic-needle residues. The drain outlet pipe 212 can be controlled by a valve synchronized with the second set of spray nozzles 206 to optimize transfer of the collected lignin sludge and/or the inorganic-needle residues to any of the primary and secondary settling tanks 136, 138. Each of the feed trays 114 can include a second weir 216 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 216, while the lignin sludge and/or the inorganic-needle residues get collected in the sump 208 of the feed tray 114.
[0082] In an exemplary embodiment, the drain outlet pipe 212 can be controlled by an actuated valve connected to the second set of spray nozzles 206. 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 206 is activated, the valve is simultaneously triggered to open the drain outlet pipe 212. 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 the lignin sludge and the inorganic-needle residues, 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.
[0083] The drain outlet pipe 212 can be controlled by an actuated valve connected with the second set of spray nozzles 206, 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 206 are actuated, the valve is actuated to open the drain outlet pipe 212 and enable the washed liquid and lignin sludge and/or the inorganic-needle residues 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.
[0084] 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 column 102 and mixes with the clean liquid coming from the centrifuge 140. In the distillation column 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 can be provided at the base of the outlet nozzle (for the reboiler liquid flow). The sump allows for additional settling time, and there can be provided an additional slurry nozzle at the base of the distillation column 102 to transport the slurry to the settling tanks 136, 138. This slurry can be mixed with the slurry coming from individual drain outlet pipes 212 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 column 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.
[0085] FIG. 3 illustrates an exemplary flow chart representation of a method 300 for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, in accordance with one or more embodiments of the present disclosure. The method 300 is carried out by the apparatus 100, as illustrated in FIG. 1. The biomass slurry and ethanol broth can contain about 21-25% w/w lignin sludge. At step 302, the method 300 includes receiving, by a feed entry nozzle 104 of a distillation unit 102, the biomass slurry and ethanol broth at a pre-defined rate.
[0086] At step 304, the method 300 includes 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. The method 300 also includes, at step 306, supplying 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.
[0087] Further, at step 308, the method 300 includes segregating, by a plurality of mesh screens 202 of at least one feed tray 114 positioned downstream of the at least one sieve tray 108, the inorganic-needle residues from the biomass slurry and ethanol broth. The method 300 also includes, at step 310, allowing, by a plurality of risers 210 of the at least one feed tray 114, the vapour generated by the reboiler 106 to escape therethrough in the vertically upward direction. At step 312, the method 300 further includes regulating, by a controller, 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 lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray 108, and actuation of a second set of spray nozzles 206 to control dispensing of a second cleaning mixture over the at least one feed tray 114 to enable collection of the inorganic-needle residues into a sump 208 of the at least one feed tray 114.
[0088] The method 300 can also include a step of segregating, by a plurality of pall rings 204 configured over the at least one sieve tray 108, the lignin sludge from the biomass slurry and ethanol broth. The step of regulating can include a step of controlling actuation of the first set of spray nozzles 112 and the second set of spray nozzles 206 based on pre-determined washing cycles. Further, the method 300 can include a step of regulating, by the controller, actuation of the second set of spray nozzles 206 to control dispensing of the second cleaning mixture over the at least one feed tray 114 to enable collection of the lignin sludge into the sump 208 of the at least one feed tray 114.
[0089] In an embodiment, the method 300 can further include a step of separating, by a centrifuge 140 of the distillation unit 102, the lignin sludge and/ or the inorganic-needle residues collected in the sump 208 of the at least one feed tray 114. The method 300 can include a step of supplying the separated lignin sludge and/or inorganic-needle residues to one or more settling tanks. The method 300 can include extracting, by an outlet nozzle 120 of the distillation unit 102, purified ethanol from the biomass slurry and ethanol broth.
[0090] With the apparatus 100 and the method 300 of the present disclosure, the purity of the ethanol azeotrope (95.5 mole %) distilled from the distillation column 102 can be achieved on a continuous process basis without any bottlenecks or intermittent troubleshooting of the distillation column 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 column 102, the product stream can 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 can then be routed to a run-down storage tank for final loading into tankers via the gantry.
[0091] Thus, the apparatus 100 and the method 300 of the present disclosure enable the efficient processing of biomass slurries and ethanol broths having high lignin content with inorganic-needle residues to produce high yields of ethanol. By optimizing the separation of the inorganic-needle residues and lignin slurry, the apparatus 100 and the method 300 can boost the efficiency of second-generation (2G) ethanol bio-refineries. The proposed apparatus 100 and method 300 can support continuous operation of the distillation column 102 by removing sharp, rigid needle-like particles, and also protecting column internals, pumps, and downstream equipment from potential erosion and mechanical damage. Further, the tortuous path created by the mesh screens 202 ensure that silica and inorganic needle residues do not interfere with vapor-liquid equilibrium, improving ethanol purity. The apparatus 100 and method 300 of the present invention can help create a more cost-effective ethanol production process by automating sludge removal and employing an efficient separation mechanism that minimizes waste generation and disposal costs. Additionally, it provides environmental benefits by effectively removing needle residues and lignin impurities, reducing solid waste discharge and supporting sustainable, eco-friendly biofuel production. The scalability of the design ensures that it can be easily adapted for various ethanol bio-refinery scales, from pilot plants to large-scale commercial operations. Furthermore, the innovative filtration efficiency of the mesh screen 202 extends the equipment lifespan by reducing long-term wear and tear on distillation column internals, ultimately improving durability and lowering replacement costs.
[0092] It will be apparent to those skilled in the art that the apparatus 100 and method 300 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0093] The present invention provides an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues.
[0094] The present invention provides an apparatus for second generation (2G) ethanol bio-refinery with inorganic-needle residues, and high-lignin laden coconut shell-frond-husk-pith feed to address the challenges associated with the inorganic-needle residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0095] The present invention minimizes the accumulation of inorganic-needle residues on sieve trays, feed trays, column internals, and heat & mass transfer/exchange surfaces of the apparatus, thereby reducing the need for frequent cleaning, downtime, and maintenance costs associated with the distillation column of the apparatus.
[0096] The apparatus and method of the present invention optimize phase separation within the distillation process by ensuring the proper distribution and trapping of silica and inorganic needle residues, improving ethanol purity and distillation efficiency.
[0097] The present invention provides a solution that maximizes the recovery of ethanol from the fermentation broth, ensuring that the ethanol produced meets or exceeds fuel-grade specifications while minimizing the loss of ethanol due to residue interference.
[0098] The apparatus and method of the present invention increase ethanol recovery efficiency by preventing the entry of solid impurities into the rectification and stripping sections, resulting in higher ethanol yields and minimal impurity contamination.
[0099] The present invention provides an apparatus designed to capture and retain rigid, sharp, needle-shaped particles, thereby minimizing erosion and mechanical wear.
[00100] The apparatus and method of the present invention help in extending the operational lifespan of the distillation column by improving filtration efficiency, reducing wear and tear on column internals.
, Claims:1. An apparatus (100) for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, wherein the apparatus (100) 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), and
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 mesh screens (202) to trap the inorganic-needle residues from the biomass slurry and ethanol broth flowing in a radial direction over the at least one feed tray (114) of the distillation unit (102); and
a plurality of risers (210) configured to allow the vapour generated by the reboiler (106) to escape therethrough in the vertically upward direction.

2. The apparatus (100) as claimed in claim 1, wherein the at least one feed tray (114) comprises a plurality of pall rings (204) arranged in a random packing arrangement to facilitate removal of the lignin sludge from the biomass slurry and ethanol broth; and a second set of spray nozzles (206) configured to spray a second cleaning mixture over the at least one feed tray (114) to prevent clogging of the lignin sludge and/or the inorganic-needle residues over the at least one feed tray (114), and enable collection of the lignin sludge and/or the inorganic-needle residue into a sump (208) of the at least one feed tray (114).

3. The apparatus (100) as claimed in claim 1, wherein the plurality of pall rings (204) 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 (208) of the at least one feed tray (114).

4. The apparatus (100) as claimed in claim 2, wherein the at least one feed tray (114) comprises:
a first feed tray (114-1) with an arrangement of the plurality of mesh screens (202), and the plurality of risers (210) in a first configuration;
at least two second feed trays (114-2) with an arrangement of the plurality of mesh screens (202), the second set of spray nozzles (206), the plurality of pall rings (204), and the plurality of rises in a second configuration,
wherein the first feed tray (114-1) and the at least two second feed trays (114-2) are arranged in a staggered manner relative to one another along a height of the distillation unit (102).

5. The apparatus (100) as claimed in claim 4, wherein the at least two second feed trays (114-2) are configured such that one of the at least two second feed trays (114-2a) is positioned downstream of the first feed tray, and other second feed tray (114-2b) among the at least two second feed trays is configured above the first feed tray within the distillation unit (102).

6. The apparatus (100) as claimed in claim 1, wherein the plurality of mesh screens (202) are configured over a moving portion (220) of the at least one feed tray (114) in a meandering manner creating a tortuous path, wherein the moving portion (220) rotates about a hinge point in a downward direction, due to weight of the collected inorganic-needle residues thereby allowing flow of the inorganic-needle residues to the sump (208).

7. The apparatus (100) as claimed in claim 5, wherein the distillation unit (102) comprises one or more sensors configured with the moving portion (220), wherein when the moving portion (220) rotates about the hinge point, the one or more sensors sense the rotation of the moving portion (220), and transmit an actuation signal to a controller, based on the sensed rotation.

8. 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.

9. The apparatus (100) as claimed in claim 1, wherein the second set of spray nozzles (206) are timer-controlled to dispense the second cleaning mixture over the at least one feed tray (114) in pre-defined time intervals.

10. The apparatus (100) as claimed in claim 7, wherein the distillation unit (102) comprises the controller configured to:
monitor clogging of the lignin sludge and/or the inorganic-needle residues received by the any of the at least one sieve tray (108) and the at least one feed tray (114);
receive the actuation signal from the one or more sensors to actuate the first set of spray nozzles (112) and the second set of spray nozzles (206); and
control actuation of the first set of spray nozzles (112) and the second set of spray nozzles (206) based on pre-determined washing cycles.

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

12. The apparatus (100) as claimed in claim 1, wherein the second cleaning mixture comprises non-equimolar mixture of acetic acid and methanol.
13. The apparatus (100) as claimed in claim 1, wherein the biomass slurry and ethanol broth contain about 21-25% w/w lignin sludge.

14. 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 the height of the distillation unit (102).

15. The apparatus (100) as claimed in claim 1, wherein the generated vapour by the reboiler (106) enters the distillation unit (102) through a vapour inlet nozzle configured near the bottom of the distillation unit (102).

16. The apparatus (100) as claimed in claim 5, wherein the at least one sieve tray (108) is configured downstream of the second feed tray (114-2a), which second feed tray is positioned downstream of the first feed tray (114-1), wherein the at least one sieve tray (108) comprises a set of protrusions or upward notches (218) arranged in a staggered manner such that the set of protrusions or upward notches (218) facilitate collection of any remaining lignin or inorganic-needle residues agglomerates from purified ethanol by hindering the flow of the purified ethanol in the radial direction which results in increased residence time for the purified ethanol over the at least one sieve tray (108).

17. The apparatus (100) as claimed in claim 1, wherein the distillation unit (102) comprises a feed entry nozzle (104) configured to 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) at a pre-defined rate.

18. 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 inorganic-needle residues and/or the lignin sludge collected in the sump (208) of the at least one feed tray (114).

19. The apparatus (100) as claimed in claim 18, wherein the distillation unit (102)comprises a centrifuge (140) configured to separate the inorganic-needle residues and/or the lignin sludge suspended in the biomass slurry and ethanol broth, and supply the separated inorganic-needle residues and/or the lignin sludge to the one or more settling tanks (136, 138).

20. The apparatus (100) as claimed in claim 1, wherein the distillation unit (102) comprises an outlet nozzle (120) configured to extract the purified ethanol from the biomass slurry and ethanol broth.

21. The apparatus (100) as claimed in claim 1, wherein the at least one sieve tray (108) comprises a first weir (214) 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 (214).

22. The apparatus (100) as claimed in claim 1, wherein the at least one feed tray (114) comprises a second weir (216) 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 (216).

23. The apparatus (100) as claimed in claim 1, wherein each of the plurality of mesh screens (202) comprising a filtration material selected from any one of: stainless steel, corrosion-resistant alloys, or synthetic polymers.

24. The apparatus (100) as claimed in claim 1, wherein the mesh screen (202) has a pore size ranging from 10 microns to 120 microns to trap the inorganic-needle residues present in the biomass slurry and ethanol broth.

25. The apparatus (100) as claimed in claim 1, wherein the mesh screen (202) has meshes arranged in such a manner that orientation of each mesh from left to right varies from 0 degree to 45 degree in upward and downward direction from a central axis of the mesh, wherein the mesh with varying angles cross intersect with each other to form a cross linked web to entangle and collect needles of varying size, nominal diameter and width.

26. The apparatus (100) as claimed in claim 1, wherein the mesh screen (202) is formed of at least one of: a woven structure, or a braided structure to increase strength and resistance to mechanical wear.

27. A method (300) for producing ethanol with a biomass slurry and ethanol broth having high lignin content with inorganic-needle residues, comprising the steps of:
receiving (302), by a feed entry nozzle (104) of a distillation unit (102), the biomass slurry and ethanol broth at a pre-defined rate;
boiling (304), 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);
supplying (306) 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 (308), by a plurality of mesh screens (202) of at least one feed tray (114) positioned downstream of the at least one sieve tray (108), the inorganic-needle residues from the biomass slurry and ethanol broth;
allowing (310), by a plurality of risers (210) of the at least one feed tray (114), the vapour generated by the reboiler (106) to escape therethrough in the vertically upward direction; and
regulating (312), by a controller, 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 lignin sludge present in the biomass slurry and ethanol broth received by the at least one sieve tray (108), and actuation of a second set of spray nozzles (206) to control dispensing of a second cleaning mixture over the at least one feed tray (114) to enable collection of the inorganic-needle residues into a sump (208) of the at least one feed tray (114).

28. The method (300) as claimed in claim 27, wherein the method (300) comprises the step of:
segregating, by a plurality of pall rings (204) configured over the at least one sieve tray (108), the lignin sludge from the biomass slurry and ethanol broth; and
regulating, by the controller, actuation of the second set of spray nozzles (206) to control dispensing of the second cleaning mixture over the at least one feed tray (114) to enable collection of the lignin sludge into the sump (208) of the at least one feed tray (114).

29. The method (300) as claimed in claim 27, wherein the step (312) of regulating comprises controlling actuation of the first set of spray nozzles (112) and the second set of spray nozzles (206) based on pre-determined washing cycles.

30. The method (300) as claimed in claim 27, wherein the biomass slurry and ethanol broth contains at least 21-25% w/w lignin sludge.

31. The method (300) as claimed in claim 27, further comprising:
separating, by a centrifuge (140) of the distillation unit (102), the lignin sludge and/ or inorganic-needle residues collected in the sump (208) of the at least one feed tray (114); and
supplying the separated lignin sludge and/or inorganic-needle residues to one or more settling tanks (136, 138).

32. The method (300) as claimed in claim 27, further comprising extracting, by an outlet nozzle (120) of the distillation unit (102), purified ethanol from the biomass slurry and ethanol broth.