百万吨天然气甲醇制乙烯技术改造

Improvements to 1mt/a NG Methanol to Ethylene Technology

天然气制甲醇原料合成气生产技术经历了常压工艺和加压工艺,现在已发展到高压转化工艺。同时实现了天然气与空气中提取的纯氧在5.5~8.5MPa压力下的自热转化工艺。而甲醇合成工艺的合成压力则从30MPa降到5~8MPa。因此采用自热转化工艺用天然气制取的合成气可在等压下合成甲醇,这样可省去动力巨大的合成气压缩机,并将自热转化气与甲醇合成副产的蒸汽分级利用。这是天然气(或页岩气)制合成气生产甲醇的创新生产技术。该技术甲醇原料单耗低[<800m^3/t(标准)]、不耗电、不排放CO_2。用该创新技术改造内蒙古博源联化的大型系列化210×10~4t/a甲醇装置,再加工成80×10~4t/a乙丙烯,成为我国重化工工业结构调整、绿色发展、创新发展的示范技术。博源联化经技术改造建成天然气为原料的节气减排CO_2的210×10~4t/a甲醇(4套合计),用其中200×10~4t/a加工生产80×10~4t/a(2套40×10~4t/a装置)乙、丙烯的特大型天然气甲醇乙烯化工基地。基地年总用天然气17×10~8m^3/a,用水电10×104k W·h,乙、丙烯年总产值约64亿元,利税约21.4亿元,总投资约80亿元,投产后4年左右可回收投资。产品乙、丙烯再综合利用深度加工,产值还可翻番,投入产出比为1∶0.80。该技术改造项目的建成投产将推动我国潜在天然气、页岩气、煤层气等资源的开发利用,具有广泛的示范作用。

The evolving technology for making the synthetic gas used for producing methanol from natural gas has been atmospheric and pressurized technology to today＇s high-pressure conversion technology.Re- searchers have also developed autothermal reforming technology in which natural gas reacts with the pure oxygen extracted from the air at a pressure between 5.5 and 8.5MPa.The pressure for methanol synthesis has dropped to 5-8MPa from 30MPa.Therefore,the synthetic gas made from natural gas using autothermal reform- ing technology can be used to synthesize methanol in an isobaric condition,eliminating the need for a syngas compressor with great power demand.The autothermal reforming gas and the steam produced in the process of methanol synthesis as a byproduct can also be utilized in a staged mode.This is an innovative process for making methanol with syngas produced from natural gas or shale gas.The technology features low feedstock consumption [〈800m3/t（standard）],zero power consumption,and zero CO2 emission.The innovative technology was introduced to Inner Mongolia Berun United Chemical Co.,Ltd.＇s 210x10^4t/a methanol unit,products from which are further processed into 80x10^4t/a of ethylene and propylene.The technology now serves as a demon- strative technology for the domestic heavy chemical industry to adjust its structure and pursue a green and innovative pathway of growth.Based on this innovative technology,Berun has established a mega natural gas, methanol and ethylene chemical industry base ,which uses natural gas as feedstock and is feedstock efficient, with small environmental footprint.The base produces 210x10^4t of methanol annually （including four facilities）, 200x10^4t/a of which is used for making 80x10^4t/a of ethylene and propylene （two units,each with a capacity of 40x10^4t/a）.The base consumes 17x10^4m3/a of natural gas and 10x10^4kW＇h of hydropower and produces around 6.4 billion yuan worth of ethylene and propylene annually.Annual profit and tax amount to 2.14 bil- lion yuan.Investment totaled about eight billion yuan.Investment can be recovered in about four years after start of production.If the ethylene and propylene produced is further processed,the output value will double. The input-output ratio is l：0.8.The project is expected to give a boost to the development and utilization of natural gas,shale gas and coalbed methane in China and serve as a good demonstrative project.