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 & ethanol broth having high lignin content with gummy-polymeric residues. More specifically, it pertains to a distillation column for second generation (2G) ethanol bio-refinery with gummy-polymeric-residues, and high-lignin laden cotton ball-shell-husk-stalks feed to address the challenges associated with the gummy-polymeric-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, such as cotton boll-shell-husk-stalks, presents significant challenges during the distillation process, primarily due to the high lignin content and the gummy-polymeric residues present in the biomass feedstock. These issues hinder the effective separation and recovery of ethanol, causing operational inefficiencies, equipment malfunctions, and increased maintenance costs.
[0004] These residues are composed of both lignin and polysaccharides, which are not easily volatilized in the distillation process. When subjected to high temperatures and pressure in distillation columns, these gummy residues create certain operational challenges. Foremost, the presence of sticky, high-viscosity polymeric residues causes significant clogging of sieve trays and other internals in the distillation column. These residues, which are not volatile like ethanol, tend to accumulate and adhere to internal surfaces of the distillation column. Over time, this accumulation creates blockages, impairing the proper flow of the liquid and vapour phases within the distillation column. This clogging disrupts the distillation process, resulting in inefficient mass transfer, lower throughput, and the need for frequent manual cleaning to restore normal operation.
[0005] Further, the accumulation of gummy-polymeric residues in the distillation column causes fouling on Mass transfer surfaces, trays, and other internal components. This fouling phenomenon significantly affects mass transfer efficiency, leading to higher energy requirements for the distillation process. As a result, operators are forced to implement frequent shutdowns for cleaning and maintenance, leading to extended downtime and an overall reduction in plant productivity. The need for manual intervention and cleaning not only adds to the labor costs but also introduces operational risks, as the cleaning process may not be entirely effective in eliminating all residues, resulting in recurring issues.
[0006] Furthermore, polymeric residues and lignin compounds not only increase the viscosity of the ethanol broth but also create a highly adhesive environment within the distillation column. This interference reduces the efficiency of vapour-liquid mass transfer, a crucial process for ethanol separation. As a result, the ability to recover ethanol efficiently from the fermentation broth is compromised. The reduced mass transfer leads to lower ethanol recovery rates, thus increasing the energy consumption and operational costs of the plant. In addition, this interference can cause the ethanol distillation process to become inefficient, resulting in a suboptimal separation of ethanol and other fermentation by-products.
[0007] Another challenge is disruption of operation of the distillation column due to accumulation of polymeric residues in a stripping section in the distillation column. The stripping section of the distillation column is designed to separate volatile compounds (such as ethanol) from the non-volatile components (such as water and impurities). The polymeric residues formed from lignin and other high-molecular-weight compounds tend to stick to the internal surfaces of the stripping section and agglomerating with lignin and thereby clogging the sieves leading to operational issues. As the residues accumulate, they disrupt the flow of the gas and liquid phases, causing misting, foaming, and pressure imbalances within the distillation column. Thus leads to poor separation efficiency and, in some cases, complete failure of the distillation column. Furthermore, these residues can result in corrosion or mechanical wear of the internal components, leading to equipment degradation and additional costs for maintenance and replacement.
[0008] In view thereof, there is need to modify design of internals of the distillation column to separate gummy-polymeric residues & lignin from the ethanol, and to ensure effective phase separation, residue attraction, and uninterrupted distillation process.
[0009] 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 & ethanol broth having high lignin content with gummy-polymeric residues.

OBJECTS OF THE PRESENT DISCLOSURE
[0010] 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 & ethanol broth having high lignin content with gummy-polymeric residues.
[0011] An object of the present disclosure is to provide a distillation column for second generation (2G) ethanol bio-refinery with gummy-polymeric-residues, and high-lignin laden cotton ball-shell-husk-stalks feed to address the challenges associated with the gummy-polymeric-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0012] An object of the present disclosure is to minimize the accumulation of gummy residues on sieve trays, column internals, and heat exchange surfaces of the apparatus, thereby reducing the need for frequent cleaning, downtime, and maintenance costs associated with the distillation column of the apparatus.
[0013] Another object of the present disclosure is to enhance vapour-liquid mass transfer within the distillation column, ensuring optimal ethanol recovery even in the presence of high-viscosity, sticky polymeric residues that typically interfere with the distillation process.
[0014] 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.
[0015] Another object of the present disclosure is to ensure efficient operation of a stripping section by preventing the accumulation of sticky residues, thus maintaining proper gas-liquid flow, pressure balance, and separation efficiency within the distillation column.
[0016] Yet another object of the present disclosure is to design a distillation column internals with self-cleaning features or anti-adhesion properties to prevent residue build up, thus improving operational continuity and reducing maintenance efforts.

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 & ethanol broth having high lignin content with gummy-polymeric residues. More specifically, it pertains to a distillation column for second generation (2G) ethanol bio-refinery with gummy-polymeric-residues, and high-lignin laden cotton ball-shell-husk-stalks feed to address the challenges associated with the gummy-polymeric-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 gummy-polymeric 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 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 wire brushes/comb/comb to remove the gummy-polymeric 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 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 gummy-polymeric residues over the at least one feed tray, and enable collection of the lignin sludge and/or the gummy-polymeric residue 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 wire brushes/comb, 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 wire brushes/comb, 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 wire brushes/comb may be configured over a moving portion of the at least one feed tray, where the moving portion may rotate about a hinge point in a downward direction, due to weight of the collected gummy-polymeric residues thereby allowing flow of the gummy-polymeric 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 gummy-polymeric 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 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 notches arranged in a staggered manner such that the set of protrusions or notches may facilitate collection of any remaining lignin or gummy-polymeric 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 gummy polymeric 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 gummy polymeric residues and/or the lignin sludge suspended in the biomass slurry and ethanol broth, and supply the separated gummy polymeric 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 from the biomass slurry and ethanol broth.
[0039] In one or more embodiments, the at least one sieve tray may include a first weir 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.
[0040] In one or more embodiments, the at least one feed tray may include a second weir 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.
[0041] In one or more embodiments, the plurality of wire brushes or combs may include a support frame, and a series of wires arranged in parallel configuration with one another, and the series of wires extending in a vertically downward direction from a horizontal portion of the support frame.
[0042] 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 gummy-polymeric 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 (also referred as “reboiler” herein), 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 wire brushes or combs of at least one feed tray positioned downstream of the at least one sieve tray, the gummy-polymeric 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 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 gummy-polymeric residues into a sump of the at least one feed tray.
[0043] 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.
[0044] 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.
[0045] In one or more embodiments, the biomass slurry and ethanol broth may contain at least 21-25% Weight/Weight (w/w) lignin sludge.
[0046] In one or more embodiments, the method may include separating, by a centrifuge of the distillation unit, the lignin sludge and/ or gummy-polymeric residues collected in the sump of the at least one feed tray. Further, the method may include supplying the separated lignin sludge and/or gummy-polymeric residues to one or more settling tanks.
[0047] 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.
[0048] 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
[0049] 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.
[0050] 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 gummy-polymeric residues, in accordance with one or more embodiments of the present disclosure.
[0051] 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.
[0052] 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 gummy-polymeric residues, in accordance with one or more embodiments of the present disclosure.

DETAILED DESCRIPTION
[0053] 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.
[0054] 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.
[0055] 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 gummy-polymeric-residues, and high-lignin laden cotton ball-shell-husk-stalks feed to address the challenges associated with the gummy-polymeric-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0056] 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 gummy-polymeric 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.
[0057] In addition, the presence of gummy-polymeric residues in distillation columns poses significant operational challenges, particularly when subjected to high temperatures and pressure. These sticky, high-viscosity residues, which are non-volatile and do not evaporate like ethanol, tend to accumulate and adhere to the internal surfaces of the column, causing clogging of sieve trays and other internals. Over time, this build up leads to blockages, disrupting the proper flow of liquid and vapour phases, thereby impairing the distillation process. The resulting inefficiencies in mass transfer reduce throughput and require frequent manual cleaning to restore normal operation. Additionally, the fouling of heat and mass exchange surfaces and other internal components severely affects heat and mass transfer efficiency, increasing energy consumption and necessitating more frequent shutdowns for maintenance. These shutdowns not only result in extended downtime, reducing overall plant productivity, but also increase labour costs and introduce operational risks, as the cleaning process may not fully eliminate the residues, leading to recurring issues.
[0058] 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 gummy-polymeric 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 cotton boll shells, cotton husks, cotton stalks, and the like, which contain about 21-25% w/w lignin sludge, which produces gummy-polymeric residues when used in the biomass slurry and ethanol broth production. In some embodiments, the biomass slurry and ethanol broth can include corn stover, rice husk, wheat straw, wood chips, peanut hulls, and the like, which also produces gummy-polymeric residues when used in the biomass slurry and ethanol broth production. These residues are generally rich in cellulose, hemicellulose, and lignin, which, when subjected to mechanical and chemical treatment, may result in gummy or viscous by-products, including polymeric substances.
[0059] The distillation column 102 will be made of material such as but not limited to stainless steel (SS-316) to counter abrasive nature of ethanol broth. 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.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] The distillation column 102 may include a vapour outlet nozzle 118, which is designed to drain the vapour generated by the reboiler 106. This vapour is directed out of the distillation 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 may 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 may be calibrated 10% higher than conventional distillation columns.
[0064] The distillation column 102 may include an outlet nozzle 120, which enables extraction of the purified ethanol from the biomass slurry and ethanol broth. The outlet nozzle 120 serves as the key point for the collection of the ethanol product that has been separated during the distillation process. The distillation 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 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.
[0065] The distillation column 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 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.
[0066] For handling heavier or more viscous liquids that may 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 may 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.
[0067] Referring to FIG. 2, each feed tray 114 includes a plurality of wire brushes or combs 202 (collectively referred as “wire brushes/comb 202” hereinafter) to remove the gummy-polymeric 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 wire brushes or combs 202 can include a support frame 202-1, and a series of wires 202-2 arranged in parallel configuration with one another. The series of wires 202-2 can be extending in a vertically downward direction from a horizontal portion 202-1a of the support frame 202-1. The horizontal portion 202-1a of the support frame 202-1 extends between at least two vertical portions 202-ba of the support frame 202-1, and the wires 202-2 can be attached to an inner surface of the horizontal portion 202-1a of the support frame 202-1. In some embodiments, the wires 202-2 can be aligned parallel to a central axis of the distillation column 102. In some embodiments, the wires 202-2 can be aligned at some angle with the central axis of the distillation column 102. The wire brushes or combs 202 can be of comb-like wire brushes or combs. The wire brushes or combs 202 can be configured over a moving portion 220 of the feed tray 114, where the moving portion 220 rotates about a hinge point in a downward direction, due to weight of the collected gummy-polymeric residues thereby allowing flow of the gummy-polymeric residues to a sump 208.
[0068] In an embodiments, the wires 202-2 can be made of corrosion-resistance materials such as but not limited to stainless steel, nickel alloys, and the like.
[0069] 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.
[0070] 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.
[0071] 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 gummy-polymeric 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 gummy-polymeric 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 non-equimolar mixture of acetic acid and methanol.
[0072] 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 gummy-polymeric 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.
[0073] 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 wire brushes/comb 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 wire brushes/comb 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.
[0074] 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 gummy-polymeric 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.
[0075] 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.
[0076] The controller may 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.
[0077] 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/notches 218 arranged in a staggered manner to facilitate collection of any remaining lignin or gummy-polymeric 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/notches 218 can be selected from but not limited to helical protrusions/notches/notches, triangular notches, rectangular notches or ridges, waffle protrusions/notches, and the like. In a preferred embodiment, the protrusions/notches 218 can be the triangular notches.
[0078] The sieve trays 108 and the feed trays 114 may be arranged in a staggered manner relative to one another along the height of the distillation 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 gummy-polymeric residues from the biomass slurry and ethanol broth.
[0079] 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 gummy-polymeric residues collected in the sumps 208 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 and/or the gummy-polymeric 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 gummy-polymeric residues 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 and/or the gummy-polymeric residues 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 moves in the vertically upward direction within the distillation column 102. The centrifuge 140 may include a drain outlet 140-1 to enable drainage of the liquid sludge.
[0080] Each of the feed trays 114 may 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 gummy-polymeric residues. The drain outlet pipe 212 may 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 gummy-polymeric residues to any of the primary and secondary settling tanks 136, 138. Each of the feed trays 114 may 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 gummy-polymeric residues get collected in the sump 208 of the feed tray 114.
[0081] In an exemplary embodiment, the drain outlet pipe 212 may 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 gummy-polymeric 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.
[0082] The drain outlet pipe 212 may 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 gummy-polymeric 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.
[0083] 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 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 column 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 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.
[0084] 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 gummy-polymeric 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.
[0085] At step 304, the method 300 includes boiling, by a heat exchanger 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.
[0086] Further, at step 308, the method 300 includes segregating, by a plurality of wire brushes/comb 202 of at least one feed tray 114 positioned downstream of the at least one sieve tray 108, the gummy-polymeric 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 heat exchanger 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 gummy-polymeric residues into a sump 208 of the at least one feed tray 114.
[0087] 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.
[0088] 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 gummy-polymeric 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 gummy-polymeric 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.
[0089] 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 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.
[0090] 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 gummy-polymeric residues to produce high yields of ethanol. By optimizing the separation of the gummy-polymeric 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 minimizing clogging issues and reducing the need for shutdowns and maintenance. The apparatus 100 also optimizes energy utilization by reducing heat loss and cleaning-related energy consumption, making the distillation process more cost-effective. 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
[0091] The present invention provides an apparatus and a method for producing ethanol with a biomass slurry and ethanol broth having high lignin content with gummy-polymeric residues.
[0092] The present invention provides an apparatus for second generation (2G) ethanol bio-refinery with gummy-polymeric-residues, and high-lignin laden cotton ball-shell-husk-stalks feed to address the challenges associated with the gummy-polymeric-residues and micro-lignin-laden ethanol broth, which significantly impact distillation efficiency.
[0093] The present invention minimizes the accumulation of gummy residues on sieve trays, column internals, and heat and mass transfer/exchange surfaces, thereby reducing the need for frequent cleaning, downtime, and maintenance costs associated with the distillation column.
[0094] The present invention enhances vapour-liquid mass transfer within the distillation column, ensuring optimal ethanol recovery even in the presence of high-viscosity, sticky polymeric residues that typically interfere with the distillation process.
[0095] The present invention maximizes the recovery of ethanol from the fermentation broth, ensuring that the ethanol produced meets or exceeds fuel-grade specifications (as per IS 15464:2004) while minimizing the loss of ethanol due to residue interference.
[0096] The distillation column of the present invention ensures efficient operation of a stripping section by preventing the accumulation of sticky residues, thus maintaining proper gas-liquid flow, pressure balance, and separation efficiency within the distillation column.
[0097] The present invention designs a distillation column internals with self-cleaning features or anti-adhesion properties to prevent residue build up, thus improving operational continuity and reducing maintenance efforts.
, Claims:1. An apparatus (100) for producing ethanol with biomass slurry and ethanol broth having high lignin content with gummy-polymeric 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 wire brushes or combs (202) to remove the gummy-polymeric 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 gummy-polymeric residues over the at least one feed tray (114), and enable collection of the lignin sludge and/or the gummy-polymeric 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 wire brushes or combs (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 wire brushes or combs (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 wire brushes or combs (202) are configured over a moving portion (220) of the at least one feed tray (114), wherein the moving portion (220) rotates about a hinge point in a downward direction, due to weight of the collected gummy-polymeric residues thereby allowing flow of the gummy-polymeric 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 gummy-polymeric 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 notches (218) arranged in a staggered manner such that the set of protrusions or notches (218) facilitate agglomeration assisted by C5-C6 sugar and momentum loss at the base of the notches and there by collection of any remaining lignin or gummy-polymeric 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 gummy polymeric 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 gummy polymeric residues and/or the lignin sludge suspended in the biomass slurry and ethanol broth, and supply the separated gummy polymeric 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 or recover 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 overflow 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 overflow through the second weir (216).
23. The apparatus (100) as claimed in claim 1, wherein the plurality of wire brushes or combs (202) comprise a support frame, (202-1) and a series of wires (202-2) arranged in parallel configuration with one another, wherein the series of wires (202-2) extending in a vertically downward direction from a horizontal portion (202-1a) of the support frame (202-1).
24. A method (300) for producing ethanol with biomass slurry and ethanol broth having high lignin content with gummy-polymeric 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 wire brushes or combs (202) of at least one feed tray (114) positioned downstream of the at least one sieve tray (108), the gummy-polymeric 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 gummy-polymeric residues into a sump (208) of the at least one feed tray (114).
25. The method (300) as claimed in claim 24, 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).
26. The method (300) as claimed in claim 24, 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.
27. The method (300) as claimed in claim 24, wherein the biomass slurry and ethanol broth contain at least 21-25% w/w lignin sludge.
28. The method (300) as claimed in claim 24, further comprising:
separating, by a centrifuge (140) of the distillation unit (102), the lignin sludge and/ or gummy-polymeric residues collected in the sump (208) of the at least one feed tray (114); and
supplying the separated lignin sludge and/or gummy-polymeric residues to one or more settling tanks (136, 138).
29. The method (300) as claimed in claim 24, further comprising extracting, by an outlet nozzle (120) of the distillation unit (102), purified ethanol from the biomass slurry and ethanol broth.