天然气三一段纯氧转化制甲醇节气增产减排CO2工艺实践与发展

重庆市万利来化工公司一套双一段空气转化制5×10^4t／a合成氨用合成气装置，采用三一段纯氧自热转化工艺改造成8×10^4t／a甲醇用合成气装置。其工艺改造的关键在于对二段炉的改造，主要采用结构特殊的混合器（烧嘴），对炉顶部结构也作相应的改造：预热器中的空气改用纯氧，还需调整脱硫后的天然气分配量、一段炉混合器负荷；增加空分装置和氧气加压输送系统等。改造后的万利来化工公司的三一段纯氧自热转化工艺包括：①外加热蒸汽转化；②换热转化；③原料天然气直接加入自热转化炉。改造后生产每吨甲醇耗用的天然气量从改造前的1000～1050m^3（标准）降低到780～800m^3（标准）；碳氢利用率由53．8％～71．4％提高到87．5％～89．7％。建议把四川某厂正在拟建的以回收炼厂气为原料．采用三一段纯氧自热转化法制甲醇的装置，作为示范装置进行总结完善，然后推广该技术。

Producing Methanol with Natural Gas Using 3-Primary Reformer Method

Chongqing Wanlilai Chemical Co.,Ltd upgraded its 5×10^4t/a syngas（used to produce synthetic ammonia） unit using the double-primary-reformer air reforming method to an 8×10^4t/a syngas unit using the 3- primary-reformer pure oxygen auto-thermal reforming （ATR） technology.The key to the upgrade was the revamping of the secondary reformer furnace.A specially engineered mixer（burner） was used and the structure of the top of the furnace was also modified.Pure oxygen was used to replace the air in the pre-heater.The distribution of sweetened natural gas and the load on the mixer of the primary reformer furnace also needed adjusting.In addition,an air separation unit and a pressurized oxygen conveying system were added.The company＇s 3-primary-reformer pure oxygen ATR process after the upgrade consists of the following three parts： ①External heating steam reforming;②heat exchange reforming;③feedstock natural gas is directly fed into ATR reformer.After the upgrade,the natural gas consumption in producing one ton of methanol dropped to 780-800m^3 from 1000-1050m^3 and the hydrocarbon utilization rate rose to 87.5%-89.7% from 53.8%- 71.4%.The authors of this article suggest using a methanol unit planned in Sichuan province,which will use the 3-primary-reformer pure oxygen ATR method,as a demonstration project to pave the way for the spread of use of the technology.