A novel waste-to-energy system based on sludge hydrothermal treatment and medical waste plasma gasification and integrated with the waste heat recovery of a cement plant

• Published in: Energy (Oxford) Vol. 305; p. 132358
• Main Authors: Li, Sarengaowa, Chen, Heng, Gao, Yue, Fan, Lanxin, Pan, Peiyuan, Xu, Gang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Cement plant; Hydrothermal treatment; Medical waste; Plasma gasification; Sewage sludge; Cement plant; Hydrothermal treatment; Plasma gasification; Sewage sludge; Medical waste
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2024.132358

A hybrid design solution is proposed to improve the waste-to-energy process by hydrothermal treatment of sludge and plasma gasification of medical waste and combining it with waste heat recovery from a cement plant. In this integrated system, the cement kiln exhaust is fed into the SP and AQC, and the resulting steam is fed into a steam turbine and generates electricity. Thus, cement kiln exhaust gas can generate electricity through the steam cycle. At the same time, sewage sludge is hydrothermally treated to produce hydrochar in the cement kiln, which is used as part of the fuel. Medical waste is used as feedstock for the plasma gasification process. The syngas produce power from a gas turbine. The hybrid design was analyzed using energy, exergy, and economic analysis. The hybrid design achieves 84.03 % energy efficiency, up to 80.29 % exergy efficiency, and up to 26.61 % net electrical energy efficiency in the energy utilization. The proposed hybrid project has a dynamic payback period of 2.64 years and achieves a net present value of 477,165.22k$ over a 25-year lifetime. The article discusses the impact of sewage sludge water content and sewage sludge treatment allowance on the performance and economics of the hybrid system. •New waste-to-energy design combining sewage sludge hydrothermal and plasma gasification.•Sewage sludge and medical waste co-processing is also included in the design.•Flue Gas Waste Heat Utilization in cement plant and gas turbine.•The new concept has an energy efficiency of 84.03 % and an exergy efficiency of 80.29 %.•The hybrid system has a 25-year DDP of 2.64 years and a NPV of 477,165.22 k$.