The Effect Of Iron-based Catalysts On Hydropyrolysis Behavior Of Tiechanggou Coal

The main purpose of this thesis was to research the effect of Iron-based catalystson hydropyrolysis behavior of tiechanggou coal. Pyrolysis behavior of Tiechanggoucoal in N₂and H₂atmosphere were investigated. And then we investigated the effectof iron-based catalysts on hydropyrolysis behavior of Tiechanggou coal. The mainresearch works and results are as follows:The effects of N₂and H₂atmosphere on the pyrolysis behavior were investigatedin a fixed-bed reactor. The produced char was characterized using TG, BET and XRDand charater of tar was measured with GC simulating distillation. The results shownthat increasing the temperature, the pyrolysis conversion of tiechanggou coal and gasyield have an increase trend in N₂and H₂atmosphere. Tar yield increase withincreasing temperature, and decrease after temperature above600℃. Water yield hasa trend of increase, the increase flatten out after500℃. H₂is more advantageous tothe coal pyrolysis,and the tar yield in hydrogen is1.2%higher than that in N₂at600℃. The reactivity of char prepared from N₂atmosphere is higher than that from H₂atmosphere，while the specific surface area of char from N₂is less than that from H₂atmosphere. The quality of tar prepared from H₂is higher than that prepared from N₂.The effect of catalysts Fe（NO₃）₃, FeCl₃and （NH₄）₂Fe（SO₄）₂prepared byimpregnation method on the hydropyrolysis behavior were investigated in a fixed-bedreactor. The role of catalyst having the highest yield of tar was investigated, and its tarwas evaluated. The results shown that adding this three catalysts, coal hydropyrolysisconversion was improved; adding （NH₄）₂Fe（SO₄）₂of5wt.%, the tar yield increasedfrom14.3wt.%daf without catalysts to17.9wt.%daf. Adding different valence ironcatalyst, the role of iron catalyst is different. The exitence of ammonium root isconducive to the improvement of coal pyrolysis conversion and tar yield. The tarprepared from （NH₄）₂Fe（SO₄）₂has a good quality compared with that preparedwithout catalyst, its quality greatly improved. The effect of the amount of adding Fe using Fe₂O₃prepared by mechanicallymixed method and catalysts ferrocene, FeOOH and Oil-soluble Fe₂O₃on the pyrolysisbehavior was investigated in a fixed-bed reactor. When add Fe₂O₃and Oil-solubleFe₂O₃, the chars were characterized using TG, BET and XRD, the tar were evaluated.The results shown that when the addition amount of iron is5wt.%, there is thehighest tar yield. Compared with no catalyst, the tar yield increase2%. Ferrocene hasalmost no catalytic effect on the coal hydropyrolysis. FeOOH is effective on thethermal crack of coal, but having a higher water yield. Oil-soluble Fe₂O₃is moreeffective on the increase of the total conversion and tar yield than the othercatalysts,and the tar yield increase3.7%high compared with that without catalystsAdding Fe₂O₃and Oil-soluble Fe₂O₃, the char reactivity is the same basically, Porestructure of char prepared from Oil-soluble Fe₂O₃is better than others. Fe grain sizeof char surface prepared from Oil-soluble Fe₂O₃（28nm） is smaller than that ofprepared from Fe₂O₃（39.5nm）. When add Fe₂O₃and Oil-soluble Fe₂O₃, the tar qualityare improved, tar prepared from Fe₂O₃is better than that of Oil-soluble Fe₂O₃.