Study On Coal Gasification For Producing Coal Gas

At present, coal gasification technology has been matured, which provides reference to gasification in metallurgy. A new type gas making furnace of slag tap process appears in order to develop the technology of injecting coal gas to BF, which can support or even replace the coal powder injection. The new technology can provide hydrogen-rich gas and simplify BF operation.Mass balance and heat balance are calculated against the new gasification technology. Against the particularity of the new technology, choice of coals, heat endurance of single or mixed coals and viscosity of coal ash slag are studied. The results are as follows:In shaft furnace, the slag is exhausted in liquid form.The qualified coal gas can be obtained when gasification temperature is controlled from 1400℃to 1500℃and the gasifying agent is air with oxygen-rich ratio 20% and water vapour content 0.4 kg/m3.The coal which has a poor heat endurance( Rw +6<60%) can achieve relatively good results when the preheating temperature is about 200~250℃, and preheating time is about 2h. Rw +6 can be enhanced up to 70%. Mixing the coals can also improve the heat endurance. A remarkable result can be achieved when the mixture ratio is about 10% against strong binding coals. Rw +6 can be up to 70% and even to 90%.By experiment, the melting temperature is the lowest when the binary alkalinity is about 0.8 and w Al2O3= 15.56%, w MgO= 9.37%, w Na2CO3= 10.51%, wT iO2= 1.91%, based on the components of shenm coal ash. When the temperature is up to 1350℃and binary alkalinity is 0.7, the fluidity of slag is the best. Low melting temperature and good fluidity slag can be obtained when the binary alkalinity is controlled at about 0.7~0.8, the Al2O3 content less than 15%, MgO content more than 10%, Na2O content more than 8%.