Calciner using recirculated gases
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. A method of making quicklime in a calciner, the method comprising:
preheating a solid carbonate material in a preheating cyclone stage operating at a temperature less than a calcination temperature of the solid carbonate material;
heating the preheated solid carbonate material in a calcination cyclone stage operating at a temperature of at least the calcination temperature to generate a solid oxide material and carbon dioxide gas;
cooling the solid oxide material in a cooling cyclone stage operating at a temperature to cool the solid oxide material to ambient temperature;
extracting a first gas from an outlet of the calcination cyclone stage and a second gas from the cooling cyclone stage;
recirculating the first gas to an inlet of the calcination cyclone stage and the second gas to the preheating cyclone stage; and
filtering, cooling, compressing, and heating the first gas prior to inserting the first gas into the inlet of the calcination cyclone stage.
2. The method of claim 1 , wherein the calciner comprises an indirect-fired vertical kiln comprising an electric kiln.
3. The method of claim 1 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 ).
4. The method of claim 1 , 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.
5. The method of claim 1 ,
wherein the solid carbonate material is preheated to a temperature from 0-900° C. in the preheating cyclone stage;
wherein the solid carbonate material is heated to a temperature from 700-1000° 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.
6. The method of claim 1
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 inserted into 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 inserted into the preheating cyclone stage.
7. The method of claim 1 comprising cooling the second gas prior to inserting the second gas into the preheating cyclone stage.
8. The method of claim 1 comprising inserting the first gas into the preheating cyclone stage and filtering and exhausting at least a portion of the first gas after extracting the first gas from the preheating cyclone stage.
9. The method of claim 1 comprising contacting the recirculated first gas and second gas in a calcination cyclone stage to generate a hot flue gas stream to contact the preheated solid carbonate material in a calcination cyclone stage.
10. The method of claim 1 , 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.
11. The method of claim 1 , 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.
12. The method of claim 1 , wherein the first gas and second gas are independently selected from the group consisting of air, steam, carbon dioxide, nitrogen, oxygen, and combinations thereof.
13. The method of claim 1 , wherein the first gas comprises carbon dioxide and steam, and the second gas comprises carbon dioxide and steam.
14. The method of claim 1 , wherein the solid carbonate material comprises a particle size from 10-100 mm.
15. The method of claim 1 , wherein the solid carbonate material comprises a particle size from 1-20 mm.
16. The method of claim 1 , wherein the solid carbonate material is preheated to a temperature from 500-900° C. in the preheating cyclone stage.
17. The method of claim 1 , wherein the solid carbonate material is preheated to a temperature from 700-900° C. in the preheating cyclone stage.
18. The method of claim 1 , wherein the solid carbonate material is heated to a temperature from 700-1050° C. in calcination cyclone stage.
19. The method of claim 1 , wherein the solid carbonate material is heated to a temperature from 700-950° C. in calcination cyclone stage.
20. The method of claim 1 , wherein the solid carbonate material is heated to a temperature from 900-1050° C. in calcination cyclone stage.