Effect Of Interaction Between Corncob Volatile And Lignite On Their Products During Pyrolysis

With the rapid development of economy in our country, the consumption of coal gradually increases leading to reduce in high quality coal reserves. Therefore, the development and utilization of the low-rank fuel including lignite and biomass energy has a positive effect on using the energy rationally and alleviating the pressure of energy shortage. Co-utilization of coal and biomass are the hot spot in the energy field. This technology can promote the sustainable use of fossil fuels, explore renewable energy sufficiently, and also reduce the environment pollution, achieve the optimal combination of energy. As the basis process of co-utilization of coal and biomass, their co-pyrolysis plays a crucial role in the subsequent use.Because of the higher ratio of H/C atom and alkali metal and alkaline earth metal elements (AAEMs) in biomass, it is possible to generate synergistic effect in the process of co-pyrolysis of coal and biomass. In order to discuss the synergistic effect of co-pyrolysis of biomass and coal further, the experiments mainly investigate the interaction corncob (CR) volatile and lignite (LR) during the pyrolysis. To examine the role of AAEMs in this process,we designed the fast pyrolysis experiments of the interaction of two kinds of corncob (corncob and demineralized corncob (CD)) volatiles with lignite and then the influences of the interaction on the distribution of pyrolysis products were determined. The conclusion mainly includes the following aspects:(1) Because of the different characteristics of corncob and lignite, the pyrolysis behaviors of corncob and lignite are not the same. Due to the effect of AAEM in CR, the char yields of CR are higher than that of CD, the yields of liquid, heavy tar and light tar from CR is lower than the CD under the lower temperature. The yields of CO2, CH4 and H2 from CR are higher than that from CD, and the yield of CO from CR is lower than that from CD.(2) The interaction between CR/CD volatiles and lignite promote the further decomposition of liquid products, making the some parts of liquid products into gases. The yields of four major gases (including CH4, H2, CO and CO2) increase. Because of the AAEMs in CR, the yields of CO2 and CH4 from CR-LR experiments are higher than that from CD-LR experiments, and the yield of H2 from CR-LR experiments are higher than that from CD-LR experiments in higher temperature.(3) The interaction between corncob volatile and lignite promote the decomposition of liquid, heavy tar, light tar and water. The yields of liquid products can be reduced by about 10%. Because of the AAEMs in CR, the yields of liquid, heavy tar, light tar and water from CD-LR are higher than that from CR-LR. The yields of phenolic products obtained from CR-LR are higher than that from CD-LR.(4) The interactions between corncob volatile and lignite have little effect on the yields of lignite char and physical structure of lignite char, but have apparent effect on the chemical structure of its char. The proportion of aromatic structure less than five rings in LR lignite chars are highest, and that of CR-LR lignite chars are lowest. Through the interaction between corncob volatile and lignite, the content of K, Na in lignite char decrease. In lower carbon conversions, the oxidation activities of LR lignite chars are highest and the oxidation activities of CR-LR lignite chars are lowest, which are consistent with the proportion of small polycyclic aromatic structure in lignite char obtained from different pyrolysis conditions.