Study On The Co-gasification Of Coal With Biomass And Tar Cracking

Atmospheric pollution have arose concern throughout the world. Especially the haze occurring in our country has been a threat to human health. For decades to come, energy-consumption pattern relying mainly on coal cannot be changed. Now in the field of high efficient and clean utilization of hydrocarbon energy, gasification technology is the key direction. The co-pyrolysis/gasification of biomass and coal is a promising way to improve their self-deficiency.In this paper, lignite (HM), Fuxin coal (FXM), beanstalk (DJ) and metasequoia (SSM) were selected as raw materials in the study of co-pyrolysis/gasification. The content of this thesis includes two parts, one is about catalytic pyrolysis of tar, and the other is co-gasification of coal and biomass. In the first part, placing different char on the fixed bed surface in advance, and the raw material fall into the reactor fast after the target temperature reached. The tar yield can be used as an important data to determine whether the char has a catalytic effect. In the second part, combined with the portable gas chromatography, the co-gasification of coal and biomass was carried out in a drop tube fixed-bed reactor.Coal char was found to have a catalytic effect on thermal decomposition of tar in the beanstalk pyrolysis experiments. Especially when taking lignite char gasified five minutes as bed additives, the yield of char was close to zero. Furthermore, the similar results were also found in the pyrolysis of lignite when taking beanstalk char as additives in the reactor. Two main reasons can explain this phenomenon, one is there exists particular physicochemical characteristics in the char, such as high surface area and developed pore structure etc. The second reason lies in the mineral elements contained in the char.Co-gasification of coal and biomass with CO2 was conducted in the second experiments. The portable gas chromatography connected to the end exit of the reactor can detect carbon monoxide concentration in gaseous product. Change the raw material type and premixed method in different test. Data indicating that there exist reactive synergy in gasification proceed of beanstalk well-mixed with lignite. No or less synergistic effects were observed in other experiments. In conclusion, gasification rate of the mixture can be influenced by biomass and coal species. The gasification velocity of coal can be improved after adding biomass. Alkali and alkaline earth metal contained in biomass play an important role in improving the rate of co-gasification. This paper can provide some value reference in the field of high efficient and clean utilization of coal and biomass energy.