Analysis And Experimental Study On Mercury Removal Process Of Coal Gasification

In this paper,the removal of mercury from coal gasification and gas as a heavy metal has been studied experimentally and numerically in a small gasifier.At first,set up a simulated experimental system structure and function is the main gas to take off the mercury: mixed gas control box for synthetic simulation gas,standard gas generator to produce mercury vapor,electric heating steam generator is used to produce steam,tube furnace reactor mercury adsorbent to take off the reaction,the tail gas absorption and processing using absorption tube and the tail gas absorption bottle,MAX-L mercury analyzer analysis of mercury.The experimental results show that: the mercury removal rate of Co modified adsorbent is the highest,62.7%,when calcined at 500? and tested at 120?.The mercury removal rate of Mn modified adsorbent increases with the increase of calcination temperature.The mercury removal rate reaches the highest at 84.04% after calcination at 500 ? and experiments at 200?.The mercury removal rate of Fe modified adsorbent decreases with the increase of calcining temperature.The mercury removal rate reaches the highest at the temperature of 200? and 120?.The model parameters of a small gasifier(the distance between the number of nozzles and the bottom of the gasifier and the ratio of height to diameter of the gasifier)were simulated and analyzed.The results showed that the particle residence time had no significant relationship with the number and Angle of nozzles,but increased with the increase of the distance between the nozzles and the bottom of the gasifier.The mass fraction of CO at the exit decreases with the increase of the number of nozzles in the gasifier,increases with the increase of the Angle of nozzles,and decreases slightly with the increase of the distance between the nozzles and the bottom of the gasifier.The weighted average temperature increases with the increase of the number of nozzles,but decreases with the increase of the Angle of nozzles.When the ratio of height to diameter is 5:1,the average temperature CO mass fraction and residence time in the furnace are maximum.For small gasifier operating conditions(pulverized coal particle size of incidence rate of oxygen coal ratio and wall temperature)simulation analysis,the results show that the particle residence time increases with the increase of incidence rate and,than there was no significant relationship with oxygen coal,pulverized coal pulverized coal particle size is 50-120?m residence time is the largest,below the surface temperature is less than 1500 K,residence time of 5.5 s,and more than 1500 K,reduced to 3 s.There was no significant relationship between the mass fraction of exit CO and the incident velocity.The mass fraction of exit CO decreased with the increase of oxygen-coal ratio and increased with the increase of wall temperature.When the coal particle size is 50-120 ?m,the average temperature in the furnace reaches the maximum,and the average temperature in the furnace reaches the maximum when the velocity is 13m/s.The average temperature in the furnace increases with the increase of wall temperature and the increase of oxycoal ratio.According to the influence of coal gasification process on mercury removal,the gasifier parameters(diameter: 300 mm,height: 1640 mm,2 nozzles,Angle: 60°,distance from the bottom of the gasifier)and working conditions(coal particle size: 120-150 ?m,incident velocity: 8m /s,oxycoal ratio: 0.8,wall temperature: 1500k)which are favorable for mercury removal are given.