Abstract:

In the context of “Emission peak, Carbon neutrality”, high CO₂ emission intensity, and low carbon utilization efficiency greatly restrict the development of the coal to methanol(CTM) process. A novel CTM process is proposed in the paper,which is near zero carbon emission by pulverized coal gasification integrated green hydrogen. In this case, the air separator and water-gas shift units can be eliminated, and acid gas removal unit also can be simplified. The key parameters are analyzed on the basis of established model of the two processes. The advantages of novel process are manifested in detail in comparison with the CTM process. The results show that the carbon utilization rate of the CTM process and the novel process are 41.50% and 95.77%, and the CO₂ direct emission intensity is decreased from 1.939 to 0.035 t·(t MeOH)^-1. An analysis of the impact of hydrogen prices and carbon taxes on product costs reveals that when the hydrogen price and carbon tax are 10.36 CNY·(kg H₂)^-1 and 223.3 CNY·(t CO₂)^-1, the production cost of two processes is equal. The new technology not only reduces carbon emissions from the CTM process, but also improves the on-site absorption capacity of renewable energy, which has good application prospects.

Key words: coal to methanol, green hydrogen, carbon dioxide, process integration, process systems, optimal design

摘要：

在“碳达峰、碳中和”的背景下，传统煤制甲醇工艺存在CO₂排放强度大、能耗高等问题成为制约煤制甲醇工艺发展的瓶颈问题。本研究基于外源性的绿氢，重构粉煤气化煤制甲醇工艺，省掉了空分单元、变换单元，开发了短流程低温甲醇洗单元，提出了粉煤气化集成绿氢的近零碳排放煤制甲醇新工艺。从碳元素利用率、CO₂排放、成本分析等角度对新工艺进行了评价。结果表明，与传统煤制甲醇工艺相比，新工艺碳元素利用率从41.50%提高到95.77%，CO₂直接排放量由1.939降低至0.035 t·(t MeOH)^-1，通过分析H₂价格与碳税对产品成本的影响发现，当氢气价格和碳税分别为10.36 CNY·(kg H₂)^-1和223.3 CNY·(t CO₂)^-1时，两种工艺的产品成本相当。新工艺不仅减少了煤制甲醇过程碳排放，而且可以提高可再生能源就地消纳能力，具有良好的应用前景。

关键词: 煤制甲醇, 绿氢, 二氧化碳, 过程集成, 过程系统, 优化设计