Innovative approach of low carbon and efficient utilization of coal resources: The polygeneration system of a combination of the gasified coal gas and the pyrolyzed coal gas to form the synthetic gas

Abstract

The present status of fossil energy resources in China reveals the fact that coal is the main energy supplier and the increasing and massive exploitation of coal and its application process such as coal burning cause serious environmental pollution which is the common concern of the government and the people. The development of low-carbon technology and the clean and efficient utilization of coal which is the high carbon resource are crucial in China’s energy development, and that is one of the ultimate goals of the Chinese social development. To realize this goal, the State Key Development Program for the Basic Research of China (973 project) (Grant No. CB2005CB221200), a national basic research project of “Applied basic researches on polygeneration system of a combination of the gasified coal gas and the pyrolyzed coal gas to form the synthetic gas” taken charge of by Taiyuan University of Technology started in 2005 supported by the Ministry of Science and Technology, more than ten other universities and research institutes have also taken part in it. This is a polygeneration project based on China’s actual conditions and the main idea is to make syngas through reforming of partial gasified gas and coke oven gas. The main products of this project are alcohol ether fuel and power. The innovative idea of this project is the reforming of coke oven gas (rich in H2 and CH4) and the gasified gas (rich in CO and CO2) to obtain syngas with optimum composition, so that it can replace the traditional way of H2 production through CO conversion, thus both CO2 emission and water consumption are reduced. Sensible feedstock composition and rational and terraced utilization of products can be realized by the polygeneration of coke, alcohol ether fuel and power. The main research aspects of this project include the following. 1) The engineering rationale of large-scale fluidized-bed pressurized gasification of coal with dual gas feed for polygeneration. 2) The reaction rule of reforming the coke oven gas and gasified gas with the presence of pyrocarbon and hydrogen adjustment without shift conversion. 3) The basic researches of desulphurization purification system under the complicated polygeneration conditions. 4) Preparation of the slurry bed catalyst and the base of new liquid phase synthesis technology. 5) Rules of intensification and control of the slurry bed based synthesis of the alcohol ether fuel, heterogeneous catalysis reaction and the integrated reaction and separation. 6) Controlled combustion in the gas turbine of the purge gas and crude gas generated during polygeneration. 7) The systematic and integrated theory of polygeneration is based on the mechanism of comprehensive and terraced utilization of chemical energy and physical energy. The five years of study resulted in remarkable progress and significant achievement which are mentioned in the above seven aspects. The main study achievements of this project can be enumerated as the following.