High Coal Ash Melting Point Solid Slag Entrained Flow Gasification Technology

High ash melting point coal is in the majority in China’s coal resources, traditional way with low efficiency and easy to cause environmental pollution. Wet flow bed coal gasification technology is more popular for coal processing and utilization, but the conventional method of liquid slag discharge is not suitable for high ash melting point coal processing and utilization. The high ash melting point coal gasification conversion is in the method of reducing gasification temperature makes the slag discharged in a non-melt state, that is the solid slag way, or wet air flow bed gasification technology, which achieved the clean and efficient utilization of high ash melting point coal resources.This paper takes two kinds of typical domestic high ash melting point coal, which are Guizhou coal and Anhui coal. Among them, the Guizhou coal has slightly lower ash, and pulp concentration is69%, the Anhui coal is with slightly higher ash ingredient, and pulp concentration can reach to71%, and full stuff property of both kinds meet the requirements of the wet air flow bed gasification. Small scale test with the raw material of Guizhou coal and pilot scale test with the raw material of Anhui coal. The small scale test shown that the solid slag discharge flow bed gasification technology for Guizhou coal gasification when the gasification temperature is1300-1400℃and the ratio of oxygen/pulp is0.6-0.7, at this point, the main technical indexes for gasification:effective gas (CO+H2) content:81.2-82.4vol%, the carbon conversion rate:95-97%, oxygen consumption:385-392Nm3/KNm3CO+H2, coal consumption:592-596kg/KNm3CO+H2, cold gas efficiency:>70%, the rate of producing gas:>2.0Nm/kg dry coal.Based on the bench-scale test, to do the pilot test separately with Guizhou coal and Anhui coal. Before the test, to mainly improve one domestic smaller wet airflow bed gasification producing equipment, adjust the existing raw material crashing size and optimize some dimensions of key equipment such as nozzle, gasification furnace, etc. The pilot test result shows the improved equipment for coal produced in Anhui province is suitable with gasification temperature zone1300-1350℃, and oxygen/coal pulp is0.6-0.75. The main gasification index is, effective gas (CO+H2) content:81-82%vol%, carbon transformation efficiency:95%-97%, oxygen consumption:380-400Nm3/KNm3CO+H2, coal consumption:590-600kg/KNm3C0+H2, cold gas efficiency:>70%, gas productivity:>2.0Nm3/kg (dry coal), the carbon content in discharging coarse slag is less than10%. The gasification index of pilot test is a little lower compared with the one in bench-scale test. This mainly caused due to the difficulty on producing high concentration coal pulp. During the pilot test, by selecting appropriate temperature, the gasification index is better than bench-scale test under same coal pulp concentration. Meanwhile, it has explored to do the pilot test to lower quality high ash melting point Anhui coal, the test shows that, the solid discharging gasification index of Anhui coal is better than the analogy calculated index, this further prove that the application of solid discharging wet flow bed technology can transform and use high ash melting coal.