Study On Characteristics Of Coal Pyrolysis Under Different Conditions And Mechanism Of Catalyst Used In Pvrolvsis

As a typical coal-rich,oil&gas-poor country,coal sumption has been occupying a very large amount in China's energy demand,and coal is still the main energy for decades in the future.How to obtain more tar and gas and improve tar quality is the main research direction of polygeneration which is an effective way for clean utilization of coal at present.In this paper,we focused on the catalyst,reaction atmosphere and reaction pressure to carry out experiment,hoping to improve the tar yield and tar quality;at the same time,the deactivation and regeneration process of the catalyst were investigated in order to improve the reliability of catalytic pyrolysis process.The influence of three kinds of catalyst arrangement,CH4 and CH4+CO2 atmosphere on pyrolysis characteristic were investigated in fixed bed.Results showed that when catalysts were arranged before and after coal separately,the yield of tar reached 17.5%at 600?C,86.8%higher than that of gray-king carbonization.The content of the light components was more than 90%,and the removal effect of the heteroatoms was remarkable.With the addition of CO2 in the CH4 atmosphe^e,combining coal pyrolysis process with the CO2/CH4 reforming process,the tar yield increased at all temperatures,and the proportion of aromatic hydrocarbons in the tar increased significantly,while the aliphatic hydrocarbons decreased correspondingly.Besides,the yield of H2 and CO increased,the sulfur content of semi-coke decreased to a great extent,performing a very good desulfurization effect.The effects of reaction pressure and partial pressure of CH4 on the yield and product characteristics of coal pyrolysis were investigated in fixed bed.The results showed that with the pressure increasing from 0.1 MPa to 3 MPa,the tar yield increased firstly and then decreased,and the tar yield reached 19.1%the highest at 2 MPa.When the total pressure of the reactor was 2MPa,the yield of tar decreased gradually with the increasing of the ratio of N2 to CH4,especially when the ratio of N2 to CH4 was 200:200,the tar was particularly decreased.The mechanism of the catalyst was investigated by thermogravimetry-infrared spectroscopy.The results showed that the catalyst could be easily carbonized at 800?,but hardly carbonized at 600?.Also,the catalyst could be regenerated by the calcination method,and the effect was remarkable.