CaO对城市生活垃圾原位水蒸气气化制备富氢燃气的影响

Influence of CaO on Hydrogen-Rich Gas Production from in-situ Steam Gasification of the Municipal Solid Waste

为高效资源化利用城市生活垃圾，提出了一种城市生活垃圾原位水蒸气气化制备富氢燃气方法．在城市生活垃圾原位水蒸气气化过程中添加CaO，对CO2进行高温吸收，促进H2产生．考察了n（Ca）In（C）（CaO与垃圾原料中碳元素的摩尔比）、反应温度及垃圾含水率等因素对H2产率以及气化特性的影响．结果表明：随着n（Ca）／n（c）由0增至1．5，φ（H2）和H2产率（以W计）分别由25．89％、10．86g／kg增至45．90％、31．56g／kg；水蒸气的引入提高了CaO的碳酸化反应活性，促进了H2的产生，但当含水率高于39．45％时，则会降低产气品质；反应温度高于750℃时，虽能强化城市生活垃圾、焦油的热分解等反应产生更多的H2，但不利于CaO的碳酸化反应，最佳的操作温度为700～750℃；对固体残留物进行XRD和SEM分析可知，反应温度高于750℃会降低CaO的活性，不利于CaO对CO2的吸收．以CaO为添加剂的城市生活垃圾原位水蒸气气化制备富氢燃气是一种有效的城市生活垃圾资源化利用方式．

Hydrogen is a promising energy to replace the fossil energy and plays an important role in the future energy systems. The municipal solid waste （MSW） with high hydrocarbon can be considered as a sustainable and renewable energy source. In order to perform efficient the energy recovery from MSW, a novel hydrogen production method in which CaO was adopted as a CO2 sorbent to increase H2 yield in the process of hydrogen production from an in-situ steam gasification of MSW was proposed. The effects of reaction n（Ca）/n（C） （ i. e. , the molar ratio between CaO and carbon element in MSW） , the reaction temperature and moisture content on hydrogen yield and gas characterization were investigated. The results showed that, with the n （Ca）/n （C） ratio increasing from 0 to 1.5, the hydrogen content and hydrogen yield increased from 25.89% to 45.90% in volume and from 10. 86 g/kg to 31.56 g/kg in mass, respectively. The introduction of the steam can improve the activity of CaO carbonation reaction by promoting the hydrogen production. The quality of the gas production was reduced, when the content of moisture was higher than 39.45% in weight. Therefore, the optimal moisture content of MSW was 39.45% in weight. The thermal decomposition of MSW and tar could be enhanced at the reaction temperature higher than 750 ℃ , which was greatly helpful for hydrogen production, but not useful for CaO carbonation reaction. The optimum operating temperature ranged from 700-750 ℃. The solid residues were characterized by XRD and SEM analysis. When the reaction temperature was higher than 750 ℃, the activity of CaO would be reduced, which is not beneficial to the adsorption of CO2. In this process, the in-situ steam gasification of MSW with CaO addition for hydrogen-rich gas production is a promising way for the MSW resource conversion.