Nowadays, due to the increase in urban population and industrial activities, the content of sewage sludge coming out of wastewater treatment processes is growing rapidly. The correct management of sewage sludge can be a promising and fruitful approach to achieve a sustainable society and environment. This article aims to propose and evaluate a hybrid sewage sludge-to-combustible fuel (containing hydrogen) conversion process. The main structure of the offered hybrid sewage sludge-to-fuel (SStF) process is designed under the three processes of pyrolysis, hydrothermal carbonization, and steam reforming. Five items of concentrations of output hydrogen and tar, gas yield, energetic efficiency, and lower heating value (LHV) were evaluated and discussed as critical parameters under different design conditions through parametric analysis. In addition, multiple linear regression Equations were developed to predict the aforementioned parameters. Further, analysis of variance was performed to identify the synergistic impacts of decision variables. Finally, the optimized design conditions and outputs of the offered hybrid SStF process were determined under a multi-objective optimization based on the response surface model. The developed structure and methodological in this article for the hybrid SStF process is a novel that had not been observed in previous reports. From the outcomes, to reduce tar formation, it is better to set the working temperatures of the hydrothermal carbonization and pyrolysis processes in higher and lower values, respectively. Moreover, under optimum working conditions of (hydrothermal carbonization process temperature and duration of 182 °C and 1.08 h, steam flow rate value of 7.02 g/s, and steam reforming and pyrolysis processes temperatures of 982.1 and 589.2 °C), a maximum hydrogen rate of around 58.43 vol%, maximum LHV value of 11.4 MJ.Nm, maximum yield of gas of 1.16 Nm.kg, and minimum tar output rate of 4.64 g.Nm under a desirability of 0.795 can be achieved. The superior performance achievable through the proposed hybrid SStF process is competitive compared to similar technologies in the literature. Therefore, the present study could provide an alternative structure for SStF or energy processes.

中文翻译：

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污水污泥-燃料混合工艺的开发和概念设计：方差和响应面模型分析下的预测和优化

如今，由于城市人口和工业活动的增加，废水处理过程中产生的污泥含量迅速增加。污水污泥的正确管理可能是实现社会和环境可持续发展的一种有前途且富有成效的方法。本文旨在提出并评估一种混合污水污泥转化为可燃燃料（含氢）的工艺。所提供的混合污水污泥制燃料（SStF）工艺的主要结构是根据热解、水热碳化和蒸汽重整三个过程进行设计的。通过参数分析，对不同设计条件下的氢气和焦油输出浓度、气体产率、能量效率和低热值（LHV）五项作为关键参数进行了评估和讨论。此外，还开发了多元线性回归方程来预测上述参数。此外，进行方差分析以确定决策变量的协同影响。最后，在基于响应面模型的多目标优化下确定了所提供的混合 SStF 工艺的优化设计条件和输出。本文所开发的混合 SStF 工艺的结构和方法是以前的报告中未曾观察到的新颖之处。从结果来看，为了减少焦油形成，最好分别将水热碳化和热解过程的工作温度设置在较高和较低的值。此外，在最佳工况条件下（水热碳化工艺温度和持续时间分别为182℃和1.08h，蒸汽流量值为7.02g/s，蒸汽重整和热解工艺温度分别为982.1和589.2℃），最大氢在理想度0.795下，可实现约58.43vol%的产率、最大LHV值11.4MJ.Nm、最大产气量1.16Nm.kg、最小焦油产率4.64g.Nm。与文献中的类似技术相比，通过所提出的混合 SStF 工艺可实现的卓越性能具有竞争力。因此，本研究可以为 SStF 或能源过程提供替代结构。