The 300,000t/a coke-oven-gas-to-methanol unit, engineered by the Sichuan Tianyi Science & Technology Company, recently went into operation at the Wuhai Shenhua Energy Company in Xilaifeng Industrial Zone. The unit produces methanol meeting the international AA standard. The methanol unit is of the world’s single largest capacity using coke-oven gas as a raw material, marking a new level of Chinese innovation of methanol-making techniques. It will play an important demonstrative role in the saving of energy, reduction of discharge, and restructuring of coking enterprises.
The methanol unit applies a patent technique for coke-oven gas purification, independently developed by Sichuan Tianyi Science & Technology. There are two major innovations involved: A. the pure oxygen conversion adopted center-diffusion tube burner, which can make the unit run continuously for more than two years, and B. low-pressure synthesis technology, tri-column rectification and energy saving process of reforming gas low-pressure heat utilization are applied, making for efficient energy saving. According to the company’s calculations, the comprehensive energy consumption of the unit stands at 41GJ/ton, 3-5GJ/ton lower than units of the same kind. It can save standard coal approximately 30,000-50,000 tons every year, and create annual sales revenue of 800 million yuan, with profits approaching 400 million yuan.
The above-scale coking enterprises produced 340 million tons of coke in 2009, generating more than 60 billion cubic meters of coke-oven gas. Some enterprises made no use of the gas, which not only causes economic losses but also brings about tremendous pollution. With the coke-oven gas-based methanol production technique, the unit can consume 600 million cubic meters of coke-oven gas, which is equivalent to a reduction of 410,000-ton sulfur dioxide emission.
The new technology also has cost advantages on its side. It can bring down the cost by 1100-1200 yuan per ton of methanol produced by the coal-based method and 800-1000 yuan by the natural gas-based method, which enables China to compete with the Middle East, which enjoys the world’s lowest cost in natural gas-based methanol production.