Systems and Methods for Alcohol Recovery and Concentration of Stillage By-Products

Abstract

Systems and methods for separating an alcohol, and in particular butanol, from a fermented feed and concentrating thin stillage into syrup includes operation of one or more alcohol recovery distillation columns using the heat supplied by steam generated from concentration of the thin stillage in a multi-train, multi-effect evaporation system.

1 - 19 . (canceled) 
     
     
         20 . A system for separating alcohol from a fermented feed and concentrating thin stillage into syrup, comprising:
 a beer column having an inlet for receiving a fermented feed, the beer column having a top outlet for discharging an alcohol-rich vapor and a beer bottom outlet for discharging alcohol-poor beer bottoms including distiller's grains and thin stillage, the thin stillage primarily including water and, optionally, solvent;   a multi-effect evaporation system for concentrating the thin stillage, the multi-effect evaporation system comprising:
 a set of first effect evaporators for evaporating water from the thin stillage to produce first effect steam and first mid stillage, the first effect evaporators including at least a first and a second first effect evaporator connected in series, wherein the first first effect evaporator has a stillage inlet in communication with the beer bottom outlet of the beer column for receiving the thin stillage of the beer bottoms and a stillage outlet for discharging stillage, wherein each subsequent first effect evaporator has a stillage inlet in communication with the stillage outlet of the previous first effect evaporator, each of the first effect evaporators having a vapor inlet for receiving heated vapor from a vapor source, each first effect evaporator is configured to cause the heated vapor to heat-exchange with the thin stillage such that water is incrementally evaporated from the thin stillage to produce the first mid stillage and the first effect steam, each first effect evaporator having a first effect steam outlet for releasing the first effect steam; 
 a set of second effect evaporators for evaporating water from the first mid stillage to produce second effect steam and second mid stillage, the second effect evaporators including at least a first and a second second effect evaporator connected in series, wherein the first second effect evaporator has a stillage inlet connected to the stillage outlet of the last first effect evaporator and a stillage outlet for discharging stillage, wherein each subsequent second effect evaporator has a stillage inlet in communication with the stillage outlet of the previous second effect evaporator, each of the second effect evaporators having a vapor inlet connected to the first effect steam outlets, each second effect evaporator is configured to cause the first effect steam to heat-exchange with the first mid stillage such that water is incrementally evaporated from the first mid stillage to produce second mid stillage and the second effect steam, each second effect evaporator having a second effect steam outlet for releasing the second effect steam; and 
 a set of third effect evaporators for evaporating water from the second mid stillage to produce third effect steam and syrup, the third effect evaporators including at least a first and a second third effect evaporator connected in series, wherein the first third effect evaporator has a stillage inlet connected to the stillage outlet of the last second effect evaporator and a stillage outlet for discharging stillage, wherein each subsequent third effect evaporator has a stillage inlet in communication with the stillage outlet of the previous third effect evaporator, each of the third effect evaporators having a vapor inlet connected to the second effect steam outlets, each third effect evaporator is configured to cause the second effect steam to heat-exchange with the second mid stillage such that water is incrementally evaporated from the second mid stillage to produce the syrup and the third effect steam, each third effect evaporator having a third effect steam outlet for releasing the third effect steam; and 
   a steam line connecting the last effect steam outlets of the last effect evaporators to a vapor inlet of the beer column such that at least a portion of the last effect steam provides heat for operation of the beer column.   
     
     
         21 . The system of  claim 20 , comprising three effects comprising three first effect evaporators arranged in series, three second effect evaporators arranged in series, and three third effect evaporators arranged in series. 
     
     
         22 . The system of  claim 20 , comprising four effects comprising two first effect evaporators arranged in series, two second effect evaporators arranged in series, two third effect evaporators arranged in series, and further comprising two fourth effect evaporators arranged in series. 
     
     
         23 . The system of  claim 20 , comprising three effects comprising four first effect evaporators arranged in series, four second effect evaporators arranged in series, and at least one third effect evaporator. 
     
     
         24 . The system of  claim 23 , comprising two to four third effect evaporators arranged in series. 
     
     
         25 . The system of  claim 20 , further comprising:
 a separator configured to separate the thin stillage from the distiller's grains of the beer bottoms;   a beer bottoms line connecting the separator and the beer bottoms outlet; and   a thin stillage line connecting the separator and the stillage inlet of the first first effect evaporator.   
     
     
         26 . The system of  claim 25 , wherein the separator is a centrifuge or filter press. 
     
     
         27 . The system of  claim 21 , further comprising a second and a third thin stillage line connected to the first thin stillage line, the stillage inlet of each of the second and third first effect evaporators being in communication with the respective second and third thin stillage lines, whereby the first, second and third first effect evaporators may receive thin stillage from the separator in parallel. 
     
     
         28 . The system of  claim 20 , wherein a pressure in the beer column at the vapor inlet is below atmospheric pressure. 
     
     
         29 . The system of  claim 20 , further comprising:
 a solvent column having an inlet for receiving a portion of the fermented feed that includes a solvent, the solvent column having a top outlet for discharging a solvent-poor and alcohol-rich vapor and a bottom outlet for a solvent-rich and alcohol-poor liquid, the solvent column being operated in parallel with the beer column; and   a second steam line connecting the last effect steam outlets of the last effect evaporators to a vapor inlet of the solvent column such that a portion of the last effect steam provides heat for operation of the solvent column, wherein a pressure in the solvent column at the vapor inlet is below atmospheric pressure.   
     
     
         30 . The system of  claim 20 , wherein the first effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator. 
     
     
         31 . The system of  claim 20 , wherein the second effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator. 
     
     
         32 . The system of  claim 20 , wherein the third effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator. 
     
     
         33 . The system of  claim 22 , wherein the fourth effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator. 
     
     
         34 . The system of  claim 20 , wherein each of the first, second and third effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator. 
     
     
         35 . The system of  claim 20 , wherein the top outlet of the beer column discharges a butanol-rich vapor. 
     
     
         36 . The system of  claim 20 , wherein the thin stillage comprises a solvent, the solvent comprising at least one of C 12  to C 22  fatty alcohols, C 12  to C 22  fatty acids, esters of C 12  to C 22  fatty acids, C 12  to C 22  fatty aldehydes, or C 12  to C 22  fatty amides. 
     
     
         37 . The system of  claim 20 , wherein the thin stillage comprises oil from the fermentation feedstock. 
     
     
         38 . A multi-effect evaporation system for concentrating thin stillage into syrup, the thin stillage being obtained as a by-product of separating alcohol from a fermented feed in a beer column, comprising:
 a set of first effect evaporators for evaporating water from the thin stillage to produce first effect steam and first mid stillage, the first effect evaporators including a first, a second, and a third first effect evaporator connected in series, wherein the first first effect evaporator has a stillage inlet in communication with the beer bottom outlet of the beer column for receiving the thin stillage of the beer bottoms and a stillage outlet for discharging stillage, wherein each subsequent first effect evaporator has a stillage inlet in communication with the stillage outlet of the previous first effect evaporator, each of the first effect evaporators having a vapor inlet for receiving heated vapor from a vapor source, each first effect evaporator is configured to cause the heated vapor to heat-exchange with the thin stillage such that water is incrementally evaporated from the thin stillage to produce the first mid stillage and the first effect steam, each first effect evaporator having a first effect steam outlet for releasing the first effect steam;   a set of second effect evaporators for evaporating water from the first mid stillage to produce second effect steam and second mid stillage, the second effect evaporators including a first, a second, and a third second effect evaporator connected in series, wherein the first second effect evaporator has a stillage inlet connected to the stillage outlet of the third first effect evaporator and a stillage outlet for discharging stillage, wherein each subsequent second effect evaporator has a stillage inlet in communication with the stillage outlet of the previous second effect evaporator, each of the second effect evaporators having a vapor inlet connected to the first effect steam outlets, each second effect evaporator is configured to cause the first effect steam to heat-exchange with the first mid stillage such that water is incrementally evaporated from the first mid stillage to produce second mid stillage and the second effect steam, each second effect evaporator having a second effect steam outlet for releasing the second effect steam; and   a set of third effect evaporators for evaporating water from the second mid stillage to produce third effect steam and syrup, the third effect evaporators including a first, a second, and a third third effect evaporator connected in series, wherein the first third effect evaporator has a stillage inlet connected to the stillage outlet of the third second effect evaporator and a stillage outlet for discharging stillage, wherein each subsequent third effect evaporator has a stillage inlet in communication with the stillage outlet of the previous third effect evaporator, each of the third effect evaporators having a vapor inlet connected to the second effect steam outlets, each third effect evaporator is configured to cause the second effect steam to heat-exchange with the second mid stillage such that water is incrementally evaporated from the second mid stillage to produce the syrup and the third effect steam, each third effect evaporator having a third effect steam outlet for releasing the third effect steam.   
     
     
         39 . The system of  claim 38 , wherein each of the first, second and third effect evaporators have valves for isolating the evaporator and bypass valves associated therewith for redirecting stillage into a line which bypasses the evaporator and reroutes the stillage to the stillage inlet of the next evaporator.