| Energy is the essential material basis for the development of society and economic growth as well as the essential element of production.Non renewable energy still plays a major role.Among them,coal resources in China and the world are very important,and will continue to remain the main position for a long time in the future.Therefore,the clean use of coal will become very important.In the clean coal technology,the gasifier and gasification of steam and gasifier under pressurized conditions make the clean fuel-syngas become more and more important,which improves the environmental pollution problem caused by the traditional coal way,which will benefit the whole society and the whole mankind.In this paper,the Fluent commercial software package is used to simulate the gasification of a three stage entrained flow gasifier with pressurized coal and steam gasification to produce syngas containing carbon monoxide and hydrogen.We need to be used in the simulation model is validated,namely simulated industrial active two stage-gasifier with these models,comparison of test results of two segment and two segment type simulation results,error within the allowable range,indicating that these models can be used.In this paper,three kinds of coal are verified by model.The results show that the error of the main parameters is not more than 5%,which indicates that the selected model is effective.Then,the verified model is used to simulate the gasification of coal powder with water vapor under pressure conditions in the three-stage airflow gasification furnace.The influence of gasification factors on gasification effect was analyzed by orthogonal analysis.The distribution of components in gasifier and gasification reaction in different parts of gasifier were analyzed.In the three-stage entrained flow gasifier,the gasification temperature increases with the increase of Ro/c.This is because the gasification reaction of pulverized coal and oxygen increases with the increase of oxygen content,and the heat released by exothermic reaction is also increasing.Ro/c indicates the ratio of oxygen quality into the quality of pulverized coal into a combustor.Carbon monoxide decreases with the increase of Rh/c.On the one hand,it is due to the water gas displacement reaction.On the other hand,when the Rh/c is high,excessive steam will dilute the effective gas in the product.Rh/c indicates the ratio of the mass of steam into the quality of the pulverized coal in the two reflux chamber.When the gasification pressure is high,the effect of gasification pressure on carbon monoxide begins to become obvious.Carbon monoxide gradually increases with the increase of gasification pressure.The mole fraction of H2 increases with the increase of Rh/c,which is due to the water gas displacement reaction.The hydrogen decreases with the increase of pressure.This is because the reaction between coke and steam is greatly influenced by pressure,and the pressure will inhibit the reaction of coke and steam.By orthogonal analysis of the influence factors on the gasification gasification effect result,in descending order,the degree of impact on coke conversion rate was pt>Ro/c>Rh/c,degree of influence on the effective gas content is Ro/c>Pt>Rh/c;the influence degree of cold gas efficiency was Ro/c>pt>Rh/c.The best combination of carbon conversion rate is pt=3MPa,Ro/c=1.2 and Rh/c=0.1.The best combination of effective gas content is pt=3MPa,Ro/c=0.8 and Rh/,=0.08,and the best combination of cold gas efficiency is pt=4MPa,Ro/c=1.2 and Rh/c=0.08.Therefore,it is suggested that the best operation combination of the three stage airflow gasifier is pt=3MPa,Ro/c=1.0,Rh/c=0.08,The optimum operation condition is the condition 2 in the nine conditions designed.Under this condition,the effective gas content is 95.97%,the coke conversion rate is 99.49%,and the cold gas efficiency is 89.9%. |
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