Study On The Influence Of Process Conditions On The Catalytic Reaction Of Methanol Synthesis

Methanol which is widely used is a kind of important chemical raw material and it is also a kind of clean liquid fuel. With the tense situation of World Energy and the development trend of the chemical industry, it becomes a trend that Methanol is used as new sources of petrochemical and coal-chemical materials. For the current situation which is the shortage of oil resources and the relative abundance of coal resources in China, the capacity has an intense competition in Methanol Industry. Therefore, how to improve the capacity effectively and how to reduce the cost of methanol production are important factors to increase the competitiveness of the methanol enterprises. Improving the methanol production capacity mainly depends on the improvement of the performance of the methanol synthesis catalyst. For this reason, there is a key significance to research the impact of Process Operating Conditions on the performance of methanol synthesis catalyst. In addition, it is also in favour of the enhancing the methanol enterprise own economic benefits. In this paper, the experimental tests were carried out in a methanol synthesis unit with a capacity of 1,800,000 tons annually designed by Davy Process Technology limited company, and the methanol synthesis catalyst was produced by Johnson Matthey Catalysts company to investigate the impact of Process Operating Conditions on catalyst activity, methanol selectivity, feed-gas conversion and space-time yield. The results can provide operational experience for the methanol enterprise.This paper researched the impact of Process Operating Conditions on the methanol synthesis reaction. The results showed that the optimum composition of make-up gas (H2-CO2) /(CO+CO2) was 2.14; The rate of methanol synthesis was approximately proportional to the pressure when the reaction rates was kinetically limited at low pressure. Increasing the pressure made for methanol synthesis reaction and methanol production. However, when the pressure increased to a certain range, the conversion was limited by chemical equilibrium. The interaction effects between pressure and methanol space-time yield was much reduced; There was optimum operating temperature which was round 235 ? as to the experimental catalyst. When Temperature was too low to reach the reaction temperature of the catalyst, it would impact on the yield and quality of methanol. When the temperature was too high, the catalyst would age faster. Within a certain range, adding more make-up gas would increase the methanol output. It was notable that the excessive make-up gas was not only to increase pressure drop through the catalyst beds and to increase the difficult to control the peak temperatures in the loop, but also to increase the power consumption of Compressor. Because of the large scale capacity of methanol industries, the methanol enterprise must consider the problem of equipment maintenance and so on; Increasing circulation rate would increase the methanol output. At very high circulation rates, the output increased slowly while the rate increased quickly, but it would increase the power-consumption of Compressor; Various process operating conditions impacting on the methanol space-time yield was different. In this paper, it was concluded the optimum process operating condition to the methanol synthesis catalyst that was the hydrogen-carbon ratio of 2.14, the pressure of 6.86 (MPa), the inlet temperature of 235?, the make-up gas flow of 275 (KNm3/h) and the recycle ratio of 5.5 through detailed analysis of the experimental data, and the marked effect on the methanol space-time yield was temperature, hydrogen-carbon ratio, make-up gas flow, pressure, recycle ratio.