Experimental Study Of Catalytically Cracking Waste Cooking Oil For Hydrogen

Catalytically cracking waste cooking oil is an effective method for producing fuel gases; however, carbon deposit peoduced in catalytic process can reduce the activity of catalysts, so reducing or eliminating carbon deposit is necessary. The further research about catalytic cracking of waste cooking oil is done based on reported literatures and includes the following parts:(1) In small catalyst evaluation device, the cracking effencies of waste cooking oil with different catalysts----Fe2O3, Al2O3, CaO and Coke are compared to find better catalyst. The cracking rule of waste cooking oil on Fe2O3at different temperature is discussed, and at the same time, the main reactions and possible mechanism of waste cooking oil cracking are studied. At the same condition, the conversion of waste cooking oil over Fe2O3is higher and carbon deposit is less. With increasing temperature, the conversion of waste cooking oil increases and gas volume percent increases while carbon deposit increases; and at the same time, Fe2O3is reduced to Fe3O4or Fe by the reducing molecules.(2) The steam reforming of waste cooking oil is simulated by ASPENPLUS and it provides theory for experimental steam reforming of waste cooking oil. In the simulation of waste cooking oil steam reforming, the proper temperature and pressure are700℃and0.1MPa. With increasing S/C, the volume percent of H2and CO2increase while those of CH4and CO decrease.(3) In order to eliminate carbon deposit, water vapor is added in the experiment. The rule of steam reforming of waste cooking oil on Fe2O3is explored and the effect of Co/C percent on waste cooking oil cracking is studied, and we study the effect of S/C on the volume percent of H2, CH4, CO and CO2, carbon deposit and waste cooking oil conversion. The experimental results show that with increasing S/C, the conversion of waste cooking oil on Fe2O3decreases and the volume percent of H2is low.The more content of Co, the higher conversion of waste cooking oil and conversion reaches100%at15%Co/C, larger volume percent of H2and volume percent reaches72%at33%Co/C and the higher carbon deposit. With33%Co/C and S/C=0.43, the carbon deposit can be totally eliminated, and with increasing S/C, H2volume percent increases from35%to49%, CH4volume percent decreases from30%to20%, CO volume percent deceases from16%to8%and CO2volume percent increases from7%to19%. The trend of gas volume percent in experiment is in accordance to those obtained by simulation with ASPENPLUS.