Methods for the Biomethanation of H2 and CO2

Abstract

The invention relates to means and methods for the biomethanation of H 2 and CO 2 . In particular, the invention relates to devices for producing methane by means of methanogenic microorganisms by converting H 2 and CO 2 , wherein the devices comprise at least one reactor, an aqueous medium, which is provided in the at least one reactor, wherein the methanogenic microorganisms are contained in the aqueous medium, a feeding apparatus, which is designed to introduce H 2 and CO 2 into the at least one reactor, wherein H 2 and CO 2 form a gaseous mixture therein, and a reaction-increasing device, which is designed to enlarge the contact surface between the aqueous medium having the methanogenic microorganisms and the gaseous mixture. The invention further relates to methods for producing methane in a reactor device by means of methanogenic microorganisms.

1 - 29 . (canceled) 
     
     
         20 . Method for production of methane in a reactor device by means of methanogenic microorganisms, which are located in the reactor device in an aqueous medium, by conversion of H 2  and CO 2  as the reaction gas mixture, characterized in that the contact surface between the aqueous medium with the methanogenic microorganisms and the gaseous mixture is increased by means of a reaction boosting device during the conversion and further characterized in that by means of a return mechanism at least a portion of the gas, which accumulates in the reactor, is returned in the reactor device, wherein a return rate of the gas accumulating in the reactor is greater than a feed rate of the reaction mixture in the reactor. 
     
     
         21 . Method according to  claim 20 , characterized in that the methanogenic microorganisms are a mixture of different microorganisms of the phylum Euryarchaeota. 
     
     
         22 . Method according to  claim 20 , characterized in that the methanogenic microorganisms are supplied in the form of macroscopic colonies (pellets) to the aqueous medium. 
     
     
         23 - 25 . (canceled) 
     
     
         26 . Method according to  claim 20 , characterized in that the reactor device has:
 at least one reactor;   an aqueous medium, which is prepared in the at least one reactor, the methanogenic microorganisms being located in the aqueous medium;   a feed mechanism, which is designed to channel H 2  and CO 2  into the at least one reactor, wherein the H 2  and CO 2  form a gaseous mixture inside it;   a reaction boosting device, which is designed to increase the contact surface between the aqueous medium with the methanogenic microorganisms and the gaseous mixture;   a return mechanism, which is designed to return at least a portion of the gas, which accumulates in the reactor, wherein the return rate of the gas accumulating in the reactor is greater than the feed rate of the substrate gas in the reactor.   
     
     
         27 . Method according to  claim 26 , characterized in that the reactor device further has a drainage mechanism, which is designed to drain a gas from the at least one reactor. 
     
     
         28 . Method according to  claim 27 , characterized in that the gas has methane. 
     
     
         29 . Method according to  claim 28 , characterized in that the quantitative fraction of methane in the gas is at least 50%. 
     
     
         30 . Method according to  claim 20 , characterized in that the return rate of the gas accumulating in the reactor exceeds the feed rate of the substrate gas in the reactor by at least a factor of 100. 
     
     
         31 . Method according to  claim 20 , characterized in that the return mechanism has a pump or a compressor. 
     
     
         32 . Method according to  claim 20 , characterized in that the device further has a circulation mechanism, which is designed to circulate the aqueous medium through the at least one reactor. 
     
     
         33 . Method according to  claim 32 , characterized in that the circulation mechanism has at least one pump. 
     
     
         34 . Method according to  claim 33 , characterized in the pump is a driving jet pump. 
     
     
         35 . Method according to  claim 20 , characterized in that the device is set up as stationary or nonstationary reactor. 
     
     
         36 . Method according to  claim 35 , characterized in that the device is a solid state reactor or a submerse reactor. 
     
     
         37 . Method according to  claim 20 , characterized in that the device is set up as continuous ideal stirred tank (CSTR), discontinuous ideal stirred tank (STR), tube reactor, loop reactor, reactors switched in series, or as cascade of reactors. 
     
     
         38 . Method according to  claim 20 , characterized in that the reaction boosting device has at least one trickling bed, one spray tower, one in-line mixer or one pump. 
     
     
         39 . Method according to  claim 38 , characterized in that the pump is a driving jet pump. 
     
     
         40 . Method according to  claim 26 , characterized in that the feed mechanism further has:
 a device for enrichment of carbon dioxide from a gas mixture; and   optionally a mechanism for electrolytic splitting of water;   wherein the feed mechanism preferably is designed so that when the H 2  and CO 2  are channeled into the at least one reactor, the gaseous mixture forms a turbulent flow.   
     
     
         41 . Method according to  claim 26 , characterized in that the feed mechanism is further designed so that, in operation, the volume of introduced H 2  and CO 2  per hour exceeds the volume capacity of the at least one reactor by at least the factor of 2, wherein the pressure in the reactor is optionally greater than or equal to 0.1 bar. 
     
     
         42 . Method according to  claim 20 , characterized in that the methanogenic microorganisms are not immobilized in the aqueous medium.