Method for improving gasification efficiency through the use of waste heat

Abstract

A method for recycling the waste heat generated from an external process, which is fuelled by syngas, into a gasification process to enhance the energy density of the syngas produced as well as the overall gasification efficiency of the system. A method is provided for utilizing the waste heat contained in a stream exiting in the syngas fueled process to vaporize water and produce steam. The steam is then upgraded by first exchanging energy with the hot syngas exiting the gasifier and then within the gasifier itself to a temperature where significant steam gasification of the biomass occurs. The process within the gasifier is driven by introducing a small amount of air into the gasifier such that some biomass is directly combusted to provide the heat required by the process.

1 ) A method for improving the efficiency of electricity production by a gasifier and generator combination, comprising: 
 a) utilizing the waste heat produced by the generator to produce low quality steam;    b) exchanging heat from the gasifier outlet stream to increase the temperature and quality of the steam;    c) introducing the steam along with some air into a suitable gasifier device; and,    d) superheating the steam through oxidation of biomass to the point where at least partial reaction between the steam and biomass occurs.    
   
   
       2 ) The method of  claim 1 , wherein a portion of waste heat produced by the generator is utilized in any biomass preparation operations.  
   
   
       3 ) The method of  claim 1 , wherein where a portion of the electricity produced by the generator is utilized in any biomass preparation operation.  
   
   
       4 ) The method of  claim 1 , wherein a portion of waste heat produced by the generator is utilized to preheat the oxygen containing stream prior to being fed into the gasifier.