Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang GongshangUniversity, Hangzhou, 310012, China.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, China.
Environ Pollut. 2022 Nov 15;313:120165. doi: 10.1016/j.envpol.2022.120165. Epub 2022 Sep 14.
Uncoupling chemical looping gasification (CLG), the organic sulfur evolution was simulated and explored qualitatively and quantitatively using typical sulfur compounds on TG-MS and temperature-programmed fixed bed. The HS radical in the reductive atmosphere easier converted to HS and COS. HO activated the evolution of S which was stably bonded to carbon, and H generated from gasification and oxidation of reductive Fe by HO contributed to the release of sulfur. The proportion of HS released from sulfur compounds was greater than 87% in steam gasification, and more than 60% during CLG. Oxygen carriers promoted the conversion of sulfur to SO in the mid-temperature region (500 °C-700 °C), and HS in the high temperature region (700 °C-900 °C). Sulfur species played a pivotal role in sulfur evolution at low temperature of CLG. The organic sulfur in mercaptan and benzyl were more easily converted and escaped than in thiophene and phenyl. The thermal stability of sulfur species, the presence of steam and OC affected the initial temperature and peak concentration of gas sulfur release as well as sulfur distribution. Consequently, CLG strengthened the sulfur evolution, and made it possible to targeted restructure the distribution of sulfur by regulating process parameters, or blending fuel with different sulfur species for emission reduction, and selective conversion of sulfur.
解耦化学链气化（CLG）中，采用典型的硫化合物在 TG-MS 和程序升温固定床中对有机硫的演化进行了定性和定量模拟研究。在还原气氛中，HS 自由基更容易转化为 HS 和 COS。HO 激活了与碳稳定结合的硫的演化，并且来自气化和 HO 氧化还原态 Fe 产生的 H 有助于硫的释放。在水蒸气气化中，从硫化合物中释放的 HS 比例大于 87%，在 CLG 期间大于 60%。载氧体促进了硫在中温区（500°C-700°C）向 SO 的转化，以及在高温区（700°C-900°C）向 HS 的转化。在 CLG 的低温下，硫物种在硫演化中起着关键作用。硫醇和苄基中的有机硫比噻吩和苯基中的更容易转化和逸出。硫物种的热稳定性、蒸汽和 OC 的存在影响了气体硫释放的初始温度和峰值浓度以及硫的分布。因此，CLG 强化了硫的演化，并可以通过调节工艺参数，或者混合具有不同硫物种的燃料来减少排放，以及选择性地转化硫，来有针对性地重新构建硫的分布。
