Method for controlling syngas production in a system with multiple feed materials

Abstract

Two or more feed materials that possess differing syngas generation potentials are mixed in a mixer and fed as a composite feed stream into a gasifier to produce syngas. By controlling the feed rate of the mixture into the gasifier as well as the feed rates of one or more of the individual feed materials into the mixer, the syngas is produced at a target production rate, with target energy content (BTU). Potential feed materials include, but are not limited to, construction and demolition (C&D) debris, municipal solid waste (MSW), other sewage-related solids, waste tires, and other substances that contain varying levels of organic compounds capable of producing a syngas.

1 . A method of producing syngas using a gasifier, comprising:
 establishing a target production rate and a target energy content for syngas output from the gasifier;   providing at least first and second feed materials as a mixture to the gasifier;   monitoring syngas being produced by the gasifier; and   based on data obtained by the monitoring step, adjusting a feed rate of the mixture to attempt to maintain the target production rate, and adjusting a feed rate of at least one of the first and second feed materials to attempt to maintain the target energy content.   
   
   
       2 . The method as described in  claim 1  where the first and second materials each have different energy content. 
   
   
       3 . The method as described in  claim 1  further including:
 analyzing data generated by the monitoring step to identify levels of carbon monoxide, hydrogen and total hydrocarbons in the syngas; and   determining BTU content of the syngas.   
   
   
       4 . The method as described in  claim 1  where the first feed material is construction & demolition (C&D) waste. 
   
   
       5 . The method as described in  claim 4  wherein the second feed material is one of:
 municipal solid waste (MSW), rubber, refuse derived fuels, wastewater sludge, scrap tires, and combinations thereof.   
   
   
       6 . The method as described in  claim 1  wherein the monitoring is initiated after the gasifier is at a steady state. 
   
   
       7 . A method of syngas production using a syngas production chamber, comprising:
 establishing a target production rate at a target energy content;   providing a set of one or more first feed materials, where each of the set of one or more first feed materials has a BTU content value above the target energy content;   providing a set of one of more second feed materials, where each of the set of one or more second feed materials has a BTU content value below the target energy content; and   prior to gasification in the syngas production chamber, mixing first feed material and second feed material to create a mixture;   controlling a feed rate of the mixture into the syngas production chamber such that an output mass flow rate of the syngas from the syngas production chamber is maintained at or near the target production rate;   controlling a feed rate of at least one of the first feed or second materials such that the syngas output from the syngas production chamber is maintained at or near the target energy content.   
   
   
       8 . The method as described in  claim 7  wherein at least two of the first feed materials are mixed prior to mixing the first feed material and second feed material. 
   
   
       9 . The method as described in  claim 7  wherein at least two of the second feed materials are mixed prior to mixing the first feed material and second feed material. 
   
   
       10 . The method as described in  claim 7  wherein at least two of the first feed materials are mixed and two of the second feed materials are mixed prior to mixing the first feed material and second feed material. 
   
   
       11 . A computer-implemented method of controlling syngas production where first and second feed materials are mixed and supplied to a gasifier, comprising:
 establishing a target production rate and a target energy content for syngas output from a gasifier;   controlling a feed rate of a mixture of the first and second feed materials into the gasifier such that an output mass flow rate of the syngas from the gasifier is maintained at or near the target production rate; and   controlling a feed rate of at least one of the first feed or second materials such that the syngas output from the gasifier is maintained at or near the target energy content.