Study On The Key Technology Of Methanol Synthesis And Electric Power Generation With Coke Oven Gas As Raw Material

Coke oven gas (COG) is high quality raw material and gas fuel with higher heat value. COG is rich in China, but in fact, the utilization amount of COG is very little and the level is very low, which not only wastes the resource, but also pollutes the environment severely. Methanol synthesis and electric power generation by gas turbine combined cycle possess widespread available prospect of using COG, but design, integration, simulation of the system haven't been studied, which prevents the utilization of COG. So, the key technology of using COG to synthesize methanol and generate electric power is studied in the paper. The main research works of the paper include as follows:The performance of producing methanol synthesis gas with COG as raw material by catalyst-based partial oxidation method is studied in the paper. The influence of oxygen-carbon ratio, water-carbon ratio and supplementary carbon before stove on the performance of catalyst-based partial oxidation and reaction product composition is analyzed in the paper. The calculation program of methanol synthesis module is written, and the process flow of methanol synthesis based on Lurgi gas phase and liquid phase technology are designed and simulated by Aspen Plus software.The mathematic models of key equipments of gas turbine combined cycle are built in the paper. The off-design performance model of axial-flow compressor is built based on blade element method. Another method of extrapolating compressor performance map based on similarity laws is put forward. The results obtained by blade element and extrapolation methods are respectively verified in the paper. The distribution and flow of cooling air is studied based on semi-experience formula, and the performance calculation model of simple cycle of PG6541B gas turbine is built and proven to be true. The conception of varying load route chart is put forward, which is proven to be the optimal load regulation way. Heat transfer density of heat exchanger of heat recovery steam generation is defined, and it's calculation method on design condition and off-design condition is studied. The performance calculation model of single-pressure heat recovery steam generation with an integral deaerator is built in the paper. The performance of gas turbine combined cycle when firing natural gas and COG is forecasted based on mathematic model of key equipment listed above.Adjustment strategies of gas turbine working condition when burning medium or low heat value fuel were deduced. The influence of each strategy on heat economy and safety operation of gas turbine was calculated quantificationally. Considering heat economy, safety and maneuverability, increasing compressor pressure ratio is optimum strategy for coke oven gas and closing inlet guide vane is optimum strategy for synthesis gas.Design scheme of poly-generation system of using COG to produce methanol and electricity is put forward. The performance of each scheme is analyzed and the result shows that the parallel-type poly-generation system of gas phase methanol synthesis and electric power generation is optimum integration scheme. The optimum methanol-electricity ratio and off-design performance of poly-generation when COG flow is changed are analyzed. Off-design strategy of poly-generation when electrical load is changed, is analyzed also, and the maximum regulating range of electrical load and performance of poly-generation is evaluated in the paper.The economy of COG utilization system, such as methanol synthesis, gas turbine combined cycle, parallel-type poly-generation system, is evaluated from the view of technical economy. The results show that all projects can make profit. Costs apportion method of poly-generation products is studied, and the sensitivity analysis is conducted in order to evaluate the degree of influence of raw material, product price and product output on the economy of each project. Economy of projects with different scales is also evaluated in order to select optimum investment project for coke oven plant with different scale.