低阶煤清洁高效梯级利用关键技术与示范

Demonstration of Key Technologies for Clean and Efficient Utilization of Low-rank Coal

        王建国(中国科学院山西煤炭化学研究所)
        赵晓红(中国科学院山西煤炭化学研究所)

         低阶煤;梯级利用;关键技术;示范;热解

        low rank coal;stage utilization;key technologies;demonstration;pyrolysis

        我国以煤为主的能源结构在未来相当长的时期内不会改变,探明煤炭储量中一半以上为低阶煤,但目前其利用方式(直接燃烧或气化)效率低、污染物和碳排放量大。为此,中科院依据低阶煤的组成与结构特征,提出了低阶煤清洁高效梯级利用的解决方案,即以高效热解为先导,提取煤中业已存在的油气资源,剩余半焦燃烧发电、或经气化定向转化为液体燃料和化学品。形成了"热解-油气提质-半焦燃烧-发电"、"热解-气化-合成"和"热解-气化-费托合成-油品共处理"三条技术路线。计划经过5—10年的努力,突破10项以上关键示范技术,形成适合我国资源特征的高能效、低污染、低排放和高值化的低阶煤综合利用技术体系,使系统能效提高5—8个百分点,硫、硝和重金属等污染物排放显著降低,CO2捕获成本降低30%—40%,以推动我国煤电和煤化工行业的技术进步。

        Coal remains the primary energy source for a long time in China.Among the proved coal reserves,low-rank coal accounts for more than 50%;however,its utilization at present via the processes like direct combustion and gasification has the problems of low efficiency,high pollutants emission and huge carbon dioxide discharge.Therefore,Chinese Academy of Sciences(CAS) has put forward a novel concept of utilizing low rank coal in stages based on its composition and structure;hence,oil and gas products arefirstly extracted through an efficient pyrolysis process and the resultant semi-cokes are then combusted cleanly or converted to liquid fuels and chemicals via gasification.Three integrated routes are proposed for the stage utilization of low rank coal:(1) upgrading of oil and gas products via pyrolysis and combustion of semi-coke for power generation;(2) synthesis of various chemicals from syngas obtained from char gasification after collecting the oil and gas products in pyrolysis stage;(3) FT synthesis from syngas and co-processing of oil from FT synthesis and that collected in the pyrolysis stage.It is expected that main issues in these routes are solved through 5-10 years efforts through research,development and demonstration;a comprehensive scheme for low rank coal utilization will be built with the characteristics of high efficiency,low pollutant emission,low carbon dioxide discharge,and high value increment of various products.Compared with the conventional utilization routes of low rank coal,the energy efficiency in the stage utilization will be increased by 5%-8%,while the emissions of sulfur,nitrate,heavy metals and other pollutants are markedly reduced and the cost for carbon dioxide capture is also lowered by 30%-40%.