Calciner using recirculated gases

Abstract

A system for making oxide material may comprise a preheating cyclone stage for receiving a solid carbonate material and operating at a temperature less than a calcination temperature of the solid carbonate material, a calcination cyclone stage for heating the preheated solid carbonate material and operating at a temperature of at least the calcination temperature to convert the preheated solid carbonate material to a solid oxide material and carbon dioxide gas, a cooling cyclone stage for cooling the solid oxide material and operating at a temperature less than the calcination temperature to cool the solid oxide material to ambient temperature, a first recirculating system to extract and recirculate a first gas from an outlet of the calcination cyclone stage to an inlet of the calcination cyclone stage zone, and a second recirculating system to extract and recirculate a second gas from the cooling cyclone stage to the preheating cyclone stage.

1 - 20 . (canceled) 
     
     
         21 . A system for making quicklime, the system comprising:
 a calciner comprising
 a preheating cyclone stage to preheat a solid carbonate material operating at a temperature less than a calcination temperature of the solid carbonate material; 
 a calcination cyclone stage to heat the preheated solid carbonate material operating at a temperature of at least the calcination temperature to generate a solid oxide material and carbon dioxide gas; and 
 a cooling cyclone stage to cool the solid oxide material operating at a temperature to cool the solid oxide material to ambient temperature; and 
   a recirculating system to extract a first gas from an outlet of the calcination cyclone stage and a second gas from an outlet of the cooling cyclone stage, and recirculate the first gas to an inlet of the calcination cyclone stage and the second gas to an inlet of the preheating cyclone stage;   wherein the recirculating system filters, cools, compresses, and heats the first gas prior to recirculating the first gas to the calcination cyclone stage.   
     
     
         22 . The system of  claim 21 , wherein the calciner comprises an indirect-fired vertical kiln comprising an electric kiln. 
     
     
         23 . The system of  claim 21 , wherein the solid carbonate material comprises at least one of calcium carbonate (CaCO 3 ), dolomitic stone (CaCO 3 ·MgCO 3 ), sodium carbonate (Na 2 CO 3 ), potassium carbonate (K 2 CO 3 ), ferrous carbonate (FeCO 3 ), manganese carbonate (MnCO 3 ), cobalt carbonate (CoCO 3 ), nickel carbonate (NiCO 3 ), cupric carbonate (CuCO 3 ), zinc carbonate (ZnCO 3 ), and aluminum carbonate (Al 2 CO 3 ). 
     
     
         24 . The system of  claim 21 , wherein the solid carbonate material comprises a particle size from 10-100 mm. 
     
     
         25 . The system of  claim 21 , wherein the solid carbonate material comprises a particle size from 1-20 mm. 
     
     
         26 . The system of  claim 21 , wherein the solid carbonate material comprises calcium carbonate (CaCO 3 ) and a balance of incidental impurities, and a particle size from 0.01-10 mm. 
     
     
         27 . The system of  claim 21 , wherein the first gas and second gas are independently selected from the group consisting of air, steam, carbon dioxide, nitrogen, oxygen, and combinations thereof. 
     
     
         28 . The system of  claim 21 , wherein the first gas comprises carbon dioxide and steam, and the second gas comprises carbon dioxide and steam. 
     
     
         29 . The system of  claim 21 , wherein the first gas and second gas comprise a hot flue gas stream to contact the preheated solid carbonate material in a calcination cyclone stage, wherein the hot flue gas stream comprises a ratio of the first gas to the second gas, based on total volume of the hot flue gas stream, from 1:1 to 50:1. 
     
     
         30 . The system of  claim 21 , wherein the first gas and second gas comprise a hot flue gas stream to contact the preheated solid carbonate material in a calcination cyclone stage, wherein the hot flue gas stream comprises a ratio of the first gas to the second gas, based on total volume of the hot flue gas stream, selected from the group consisting of 1:1, 2:1, 5:1, 10:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, and 50:1. 
     
     
         31 . The system of  claim 21 , wherein the outlet of the calcination zone is in fluid communication with the inlet of the calcination zone along a first flow path. 
     
     
         32 . The system of  claim 21 , wherein the recirculating system comprises at least one heat exchanger to cool the first gas prior to recirculating the first gas to the inlet of the calcination cyclone stage. 
     
     
         33 . The system of  claim 21 , wherein the recirculating system comprises at least one heat exchanger to compress the first gas prior to recirculating the first gas to the inlet of the calcination cyclone stage. 
     
     
         34 . The system of  claim 21 , wherein the recirculating system comprises at least one heat exchanger to cool the second gas prior to recirculating the second gas to the preheating cyclone stage. 
     
     
         35 . The system of  claim 21 , wherein the recirculating system comprises at least one filter to filter the first gas prior to recirculating the first gas to the inlet of the calcination cyclone stage. 
     
     
         36 . The system of  claim 21 , wherein the recirculating system comprises at least one heater to heat the first gas prior to recirculating the first gas to the inlet of the calcination cyclone stage. 
     
     
         37 . The system of  claim 21 , wherein the recirculating system comprises at least one blower to pressurize the first gas prior to recirculating the first gas to the inlet of the calcination cyclone stage. 
     
     
         38 . The system of  claim 21 , wherein the recirculating system comprises at least one vent to exhaust at least of portion of the first gas after extracting the first gas from the preheating cyclone stage. 
     
     
         39 . The system of  claim 21 ,
 wherein the solid carbonate material is preheated to a temperature from 0-900° C., 500-900° C., or 700-900° C. in the preheating cyclone stage;   wherein the solid carbonate material is heated to a temperature from 700-1000° C., 700-1050° C., 700-950° C., or 900-1050° C. in calcination cyclone stage; and   wherein the solid carbonate material is cooled to a temperature from 20-300° C. in the cooling cyclone stage.   
     
     
         40 . The system of  claim 21 ,
 wherein the first gas has a temperature of 700-1100° C. when extracted from the outlet of the calcination cyclone stage and a temperature of 900-2000° C. when recirculated to the inlet of the calcination cyclone stage; and   wherein the second gas has a temperature of 500-1000° C. when extracted from the cooling cyclone stage and a temperature of 500-1000° C. when recirculated to the preheating cyclone stage.