Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Waste Manag. 2022 May 1;144:132-143. doi: 10.1016/j.wasman.2022.03.018. Epub 2022 Mar 26.
In general, sewage sludge obtained from the municipal wastewater treatment plant is one of the significant sources of waste for renewable energy production. In this article, the thermochemical conversion of sewage sludge through a downdraft gasifier is addressed. Two-zone equilibrium and one-zone kinetic model as the hybrid modeling of the sewage sludge gasification is proposed. Three zones of drying & pyrolysis, oxidation, and (char) reduction are modeled by using an integrated thermodynamic stoichiometric equilibrium and Langmuir-Hinshelwood kinetic model. Through the validation and sensitivity analysis, the syngas compositions and cold gas efficiency show to be sensitive to the variations of inlet flow rates of gasifying agents (air and steam), the inlet flow rate of feedstock (sewage sludge), and the temperature and pressure of the gasifier. Through the response surface methodology-based optimization algorithm, the proper operating conditions of the process can be found under the prescribed operating constraints.
一般来说，城市污水处理厂产生的污水污泥是可再生能源生产的重要废物来源之一。本文讨论了通过下吸式气化炉对污水污泥的热化学转化。提出了采用两段式平衡和一段式动力学模型对污水污泥气化进行混合建模。使用集成的热力学化学平衡和朗缪尔-欣谢尔伍德动力学模型对干燥和热解、氧化和（炭）还原三个区域进行建模。通过验证和敏感性分析，发现合成气成分和冷煤气效率对气化剂（空气和蒸汽）的入口流量、进料（污水污泥）的入口流量以及气化炉的温度和压力的变化很敏感。通过基于响应面法的优化算法，可以在规定的操作条件下找到该过程的合适操作条件。
