State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences

燃煤造成的大气污染严重影响我国燃煤电厂的可持续发展,亟待探索高效、超低排放的燃煤发电技术。将煤粉在超临界水中氧化,产生的化学能直接释放至水中,产生超临界水/CO2复合工质,推动汽轮机做功发电,工质做功后可直接回收高浓度CO2,实现煤炭的近零排放燃烧发电。采用红外光谱研究脱除矿物质后西岔沟煤中有机官能团变化,以脱除矿物质的西岔沟煤为原料,研究反应终温400~600℃、氧气当量比1.0~1.4条件下,脱灰煤在超临界水氧化环境下的反应特性以及碳、氮、硫元素的迁移规律。结果表明,酸碱联合法脱灰对西岔沟煤结构的影响较小,煤大分子脂肪侧链变短,芳碳率略增加。西岔沟脱灰煤在超临界水中氧化,温度和氧化剂用量对煤转化率的影响较大,气相产物以CO2为主,不产生NOx和SOx,低温下有少量CO和H2生成。反应终温超过500℃后,转化的碳被完全氧化为CO2。提高反应终温和氧化剂用量,煤中C、N、S等元素的转化率提高,在反应终温550℃,氧化剂为化学计量的1.4倍条件下,C、N、S转化率分别达97.08%、94.52%和94.41%。

The emission of pollutants during the coal combustion process has severely hindered the sustainable development of coal-firedpower plant, and it is urgent to explore efficient and ultra-low emission coal-fired power generation technologies. By oxidizing coal powderin supercritical water, the chemical energy generated is directly released into the water, producing a supercritical water/ CO2 compositeworking fluid that drives the steam turbine to work and generate electricity. After working with the working fluid, high concentrationCO2 can be directly recovered, achieving near zero emission combustion and power generation of coal. The effects of mineral removalon coal structure was studied by FTIR. The oxidation reaction characteristics of ashless Xichagou coal and the transformation of carbon,sulfur and nitrogen in supercritical water were studied under the conditions of the temperature region of 400-600 ℃ and oxidant equivalence ratio region of 1.0-1.4. The results show that demineralization by the acid alkali combined method has little effect on the structure ofXichagou coal, with shorter side chains of coal macromolecular fat and a slight increase in aromatic carbon content. The Xichagou deashing coal is oxidized in supercritical water, and the temperature and amount of oxidant have a significant impact on the coal conversion rate.The gas phase products are mainly CO2 during supercritical water oxidation, without producing NOx and SOx. Small amount of CO and H2are detected at temperatures lower than 500 ℃ . When the final reaction temperature exceeds 500 ℃ , the converted carbon is completelyoxidized to carbon dioxide. The conversion of carbon, nitrogen, and sulfur in coal increases with the increase of final temperature and theamount of oxidant. At the final reaction temperature of 550 ℃ and the oxidant being 1.4 times stoichiometric, the conversion rates of C, Nand S reach 97.08%, 94.52% and 94.41%, respectively.

山西省重点研发计划资助项目(201903D121016,202102090301029)

张荣,赵学超,刘植昌,等.西岔沟脱灰煤超临界水氧化过程中元素转化规律[J].洁净煤技术,2023,29(12):95-102.

ZHANG Rong,ZHAO Xuechao,LIU Zhichang,et al.Element transformation rule of Xichagou ashless coal during the supercritical water oxidation process[J].Clean Coal Technology,2023,29(12):95-102.