System and method of generating electricity

Abstract

A system and associated method of processing solid waste via a waste gasification process resulting in usable by-products may be used to generate electricity. The method utilizes a rotary kiln heated to a temperature of at least 800° F., a reduction chamber, heated to a temperature of at least 1800° F. and a boiler downstream of the reduction chamber. Steam generated in the boiler powers a turbine which operates a generator for generating electricity. Dampers may be positioned to bypass the power generation system. Gases are monitored and transported from the reduction chamber to at least one air pollution control unit to remove contaminants before being vented into the atmosphere.

1 . A method of generating electricity comprising: 
 heating a rotary kiln;    feeding waste into the rotary kiln;    rotating the rotary kiln, thereby generating gases and residual solids;    removing the residual solids from the rotary kiln;    transporting the gases from the rotary kiln to a reduction chamber;    heating the gases in the reduction chamber;    transporting gases from the reduction chamber to a boiler to create steam;    transporting steam from the boiler to a steam turbine to operate the turbine; and    rotating an output shaft of the steam turbine to power a generator for generating electricity.    
   
   
       2 . The method of  claim 1  further comprising transporting gases from the boiler to a spray dryer absorber.  
   
   
       3 . The method of  claim 2  further comprising treating the gases in the spray dryer absorber to remove contaminants.  
   
   
       4 . The method of  claim 3  further comprising transporting the gases from the spray dryer absorber to a baghouse; and 
 removing further contaminants from the gases in the baghouse.    
   
   
       5 . The method of  claim 1  wherein the step of heating the rotary kiln comprises heating the rotary kiln to at least 800 degrees Fahrenheit.  
   
   
       6 . The method of  claim 1  wherein the step of heating the gases in the reduction chamber comprises heating the reduction chamber to at least 1,800 degrees Fahrenheit.  
   
   
       7 . The method of  claim 1  wherein the reduction chamber is maintained at between approximately 1800-2400 degrees Fahrenheit.  
   
   
       8 . The method of  claim 1  further comprising cooling gases exiting the boiler before they enter the spray dryer absorber.  
   
   
       9 . The method of  claim 1  further comprising maintaining the gases entering the spray dryer absorber at a temperature of approximately 500 degrees Fahrenheit.  
   
   
       10 . The method of  claim 1  wherein the step of cooling the gases exiting the boiler comprises spraying water into the gases.  
   
   
       11 . The method of  claim 1  wherein the step of removing further contaminants from the gases in the baghouse comprises passing the gases through filters.  
   
   
       12 . A method of processing waste, said method comprising: 
 feeding the waste into an interior of a rotary kiln at a predetermined feed rate;    rotating the rotary kiln at a predetermined rotation speed;    introducing air into the interior of the rotary kiln;    heating the solid waste in the interior of the rotary kiln, thereby generating gases and residual solids;    ducting the gases generated in the rotary kiln to a reduction chamber;    adjusting at least one of the feed rate of the solid waste into the interior of the rotary kiln, rotation speed of the rotary kiln, and airflow into the interior of the rotary kiln to maintain the temperature of the gases exiting the rotary kiln at between 800-1200 degrees Fahrenheit;    ducting the gases from the reduction chamber to a boiler;    transporting steam from the boiler to a steam turbine to rotate an output shaft of the turbine to power a generator for generating electricity.    
   
   
       13 . The method of  claim 12  further comprising transporting gases from the boiler to a spray dryer absorber.  
   
   
       14 . The method of  claim 13  further comprising cooling the gases exiting the boiler prior to the gases entering the spray dryer absorber.  
   
   
       15 . The method of  claim 13  further comprising transporting the gases from the spray dryer absorber to at least one air pollution control unit; and 
 removing contaminants from the gases.    
   
   
       16 . The method of  claim 12  wherein gases generated in the boiler are transported from the boiler to a spray dryer absorber and then to a baghouse.  
   
   
       17 . A method of generating power by processing solid waste, said method comprising: 
 heating a rotary kiln having a feed chute at a first end and a discharge chute at a second end to maintain the temperature of the rotary kiln above 800 degrees Fahrenheit;    feeding the solid waste into the rotary kiln via the feed chute;    rotating the rotary kiln, thereby separating generated gases from residual solids;    transporting the generated gases from the rotary kiln to a reduction chamber;    heating the gases in the reduction chamber;    transporting the gases from the reduction chamber to a boiler;    transporting gases from the boiler to a spray dryer absorber;    using steam from the boiler to drive a steam turbine for generating electricity;    transporting gases from the spray dryer absorber to air pollution control units; and    removing particulate from the gases in the air pollution control units.    
   
   
       18 . A system for processing solid waste, said system comprising: 
 a rotary kiln having drive means for rotating the rotary kiln;    a feeder for feeding said solid waste into said rotary kiln;    a heating system for heating the rotary kiln;    a reduction chamber adapted to receive and bum gases generated in the rotary kiln;    a heating system for heating the reduction chamber;    a boiler for generating steam; and    a steam turbine for powering a generator for generating electricity.    
   
   
       19 . The system of  claim 18  further comprising at least one air pollution control unit located downstream of the reduction chamber, each air pollution control unit being adapted remove contaminants from said gases.  
   
   
       20 . The system of  claim 18  wherein said at least one air pollution control unit includes a spray dryer absorber and a baghouse.  
   
   
       21 . The system of  claim 20  further comprising a combustion control system including a plurality of temperature probes for monitoring the temperature of said gases entering the spray dryer absorber.  
   
   
       22 . The system of  claim 20  further comprising at least one misting nozzle to cool the gases exiting the boiler.