Study On Influence Of Blending Coal And Fluxing Agent On Coal Ash Of Shell Gasifier

In recent years,coal gasification plants have been developed rapidly,but there are often two problems in their operation: the frist is the slag outlet of the gasifier is blocked by slag,and the other is the ash is deposited in the syngas cooler of the gasifier,which can lead to coal gasification plants operating load is reduced and the operating cycle is short.Therefore,in this paper,four coals from Xiaozhuang,Queshan,Zhaogu,and Shenmu,were investigated.Coal blending and addition amount of flux limestone are influence on coal ash fusion temperature and acid-base ratio and silica-alumina ratio of coal ash group was studied.The Shell gasifier was used for the combustion test of various suitable coal types to find a better coal blending process with long period operation and high conversion rate of the coal gasification unit.The influence of the addition amount of fluxing agent on the coal ash fusion temperature,acid-base ratio and silicon-aluminum ratio was investigated.The addition of limestone can effectively reduce the coal ash melting temperature,so that the coal ash fusion temperature of the raw coal can be reduced to the standard requirements of 1350 °C.The addition of limestone can obviously change the acid-base ratio in coal ash component,and it can be adjusted to 5 or less.But without effect on silicon-alumina ratio in the coal ash component,it cannot adjust the silicon-alumina ratio to the required range of 1.9-2.1.Four raw coal were blended in pairs to adjust the blending ratio,and the influence of blending coal on coal ash fusion temperature,acid-base ratio,and silicon-aluminum ratio were examined.Coal blending can effectively adjust the silicon-alumina ratio in coal ash components to satisfing Shell coal gasification process requirements.However,the change in the coal ash fusion temperature and acid-base ratio in the coal ash components through coal blending is no regular,and it is difficult to satisfy the process requirements of the coal gasification.Considering the combination of coal blending and limestone addition,which effect on coal ash fusion temperature,acid-base ratio,and silica-alumina ratio was investigated.The silica-alumina ratio was adjusted by coa blendingl,then limestone was added to adjust the ash fusion temperature and acid-base ratio.Finally,15 proportions being suitable for the Shell coal gasification process were found,making the Shell gasifier reach the basic conditions for operation.The operating parameters of the Shell gasifier were collected,and the influence of the amount of limestone added on the synthesis gas components and operation of the gasifier was further investigated.In the 15 ratios,the better ratio,1:1 Zhaogu-Shenmu and 3%-4% limestone,was selected.The syngas with an effective gas CO content of up to 68% was obtained,and the slagging and depositing of the gasifier was improved.The plant was operated stably for 133 days,and the daily average methanol production was as high as 2,000 tons,the better economic benefits was created.