Method of sustained microbial production of hydrogen gas in a bioreactor utilizing an equalization tank

Abstract

The present invention provides a method of hydrogen production from microorganisms, wherein a bioreactor provides an environment conducive to the production of hydrogen from hydrogen producing microorganisms and restrictive to the production of methane from methanogens. The method further includes an equalization tank that provides improved control of flow rates, particularly when combining the hydrogen production system with an industrial process such that organic feed material obtained from the industrial process is utilized in the hydrogen production system. The environment in the bioreactor is preferably maintained between about 3.5 and 6.0 pH.

1 . A method for producing hydrogen from hydrogen producing microorganisms metabolizing an organic feed material and controlling a rate of mixing of the organic feed material, comprising: 
 conveying the organic feed material from a reservoir to an equalization tank through a first passage at a first flow rate,    conveying excessive organic feed material from the equalization tank to the reservoir through a second passage,    conveying non-excessive organic feed material from the equalization tank to a heater through a third passage at a second flow rate,    wherein the second flow rate is less than the first flow rate,    treating the organic feed material,    introducing the organic feed material into a bioreactor, and    adjusting the pH of the organic feed material in the bioreactor to a pH between about 3.5 to 6.0 pH.    
   
   
       2 . The method of  claim 1 , wherein the treating of the organic feed material includes heating the organic feed material to a temperature of about 60 to 100° C.  
   
   
       3 . The method of  claim 1 , wherein the organic feed material is adjusted to a pH of about 3.5-6.0 pH in the bioreactor.  
   
   
       4 . The method of  claim 1 , wherein the organic feed material in the bioreactor is an effluent from an industrial production process.  
   
   
       5 . The method of  claim 4 , wherein the effluent from the industrial production process is captured in the reservoir.  
   
   
       6 . The method of  claim 5 , wherein effluent is a sugar containing aqueous material.  
   
   
       7 . The method of  claim 5 , wherein the effluent is a waste product from a juice manufacturing process.  
   
   
       8 . The method of  claim 1 , wherein treating the organic feed material includes adjusting electrolytes of the organic feed material.  
   
   
       9 . The method of  claim 1 , wherein the flow rates are adjustable.  
   
   
       10 . The method of  claim 2 , wherein the organic feed material is heated to a temperature of about 60 to 75“C.  
   
   
       11 . The method of  claim 1 , wherein the hydrogen producing microorganisms metabolize sugar contained in the organic feed material under the reactions  
       Glucose→2 Pyruvate   (1)  2 Pyruvate+2 Coenzyme A→2 Acetyl-CoA+2 HCOOH   (2)  2 HCOOH→2 H 2 +2 CO 2    (3).  
   
   
       12 . The method of  claim 1 , wherein the hydrogen containing gas substantially contains hydrogen and carbon dioxide in a 1:1 ratio.  
   
   
       13 . The method of  claim 1 , wherein the organic feed material is retained in the heater for a period of about 45-90 minutes.  
   
   
       14 . The method of  claim 1 , wherein the organic feed material is treated for a period of about 6 to 24 hours.  
   
   
       15 . The method of  claim 1 , wherein the hydrogen producing microorganisms metabolizing the organic feed material has an ORP of about −300 to −450 mV.  
   
   
       16 . The method of  claim 1 , further comprising the step of removing gas from the bioreactor.  
   
   
       17 . The method of  claim 1 , further comprising the step of cleaning the gas removed from the bioreactor to substantially remove carbon dioxide.  
   
   
       18 . The method of  claim 1 , further comprising the step of inoculating the organic feed material with hydrogen producing microorganisms.  
   
   
       19 . The method of  claim 1 , wherein a pump is operably related to the first passage.  
   
   
       20 . The method of  claim 1 , wherein a pump is operably related to the third passage.