Use of fermentation tail gas in integrated gasification and gas fermentation system

Abstract

The disclosure provides for the separation and combustion of at least one hydrocarbon, oxygenate, sulfur compound, and or nitrogen compound, from industrial gas or gasification derived syngas to generate steam. A gasification process and a gas fermentation process may be integrated using tail gas from the fermentation process for the flame to combust tar and other compounds from the syngas generated by a gasification process. Integration may be achieved by removing tar and other compounds from industrial gas or gasification derived syngas using an adsorbent and regenerating the adsorbent using tail gas from the gas fermentation process. Tail gas enriched with the desorbed tar and other compounds may be used to generate steam in a steam boiler and the steam may be used for a variety of purposes including power generation to power, for example, a compressor of the gas fermentation process.

1 . A method comprising:
 a. gasifying a gasification feedstock to produce syngas comprising at least carbon monoxide, hydrogen, water, and tars;   b. cooling the syngas to separate water and at least one tar by condensation and provide a remainder of the syngas depleted in water and at least one tar;   c. disposing of the at least one tar by:
 i. combusting the at least one tar using a flame produced by the combustion of fuel gas, natural gas, syngas, tail gas from a gas fermentation process, or any combination thereof; or 
 ii. passing the at least one tar to a wastewater treatment process; and 
   d. fermenting at least a portion of the remainder of the syngas in a bioreactor using a microorganism to generate an effluent comprising at least one product.   
     
     
         2 . The method of  claim 1  further comprising removing at least a second tar from the syngas by adsorption using an adsorbent. 
     
     
         3 . The method of  claim 2  wherein the fermenting further generates the tail gas. 
     
     
         4 . The method of  claim 3  further comprising regenerating the adsorbent using the tail gas. 
     
     
         5 . The method of  claim 4  further comprising utilizing the tail gas after regenerating the adsorbent to generate steam. 
     
     
         6 . The method of  claim 5  further comprising using the steam to generate electricity. 
     
     
         7 . The method of  claim 6  further comprising using the electricity to power a compressor of the fermenting step. 
     
     
         8 . An apparatus comprising:
 a. an adsorption unit housing an adsorbent;   b. a bioreactor in fluid communication with the adsorption unit;   c. a tail gas conduit in fluid communication with the bioreactor and the adsorption unit;   d. an enriched tail gas utilization unit comprising at least one of
 i. a gasifier in fluid communication with the adsorption unit; 
 ii. a steam generation unit; 
 iii. a power production unit; or 
 iv. a product recovery unit in fluid communication with the bioreactor; and 
   e. an enriched tail gas conduit in fluid communication with the adsorption unit and the enriched tail gas utilization unit.   
     
     
         9 . The apparatus of  claim 8  further comprising a steam conduit in fluid communication with the steam generation unit and a power generation system. 
     
     
         10 . The apparatus of  claim 9  further comprising a compressor in electrical communication with the power generation system and in fluid communication with the bioreactor. 
     
     
         11 . The apparatus of  claim 8  wherein the power production unit is a cogeneration power production unit or a direct power production unit. 
     
     
         12 . The apparatus of  claim 8  further comprising a feedstock conduit in fluid communication with the adsorption unit.