Co-pyrolysis of saw dust and oily sludge with waste-heat utilization of steel slag on rotary kiln simulated engineering practice

• Published in: Fuel (Guildford) Vol. 364; p. 131012
• Main Authors: Yu, Hongdi, Lin, Fawei, Guo, Xuan, Yao, Hongyun, Zheng, Fa, Li, Jiantao, Zhang, Meng, Li, Rundong, Yan, Beibei, Chen, Guanyi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.05.2024
• Subjects: Co-pyrolysis; Oily sludge; Soil remediation; Waste heat utilization; Soil remediation; Waste heat utilization; Oily sludge; Co-pyrolysis
• DOI: 10.1016/j.fuel.2024.131012
• ISSN: 0016-2361

[Display omitted] •The sawdust was introduced into oily sludge can achieve physical viscosity reduction.•Steel slag possessed dual effect of catalysis and heating for the pyrolysis of oily sludge.•Simulation indicated that fins and rotation of rotary kiln significantly improve heat transfer efficiency.•The pyrolysis residue of oily sludge and sawdust possessed the potential for soil remediation. Pyrolysis of oily sludge (OS) possesses actual problems of high viscosity and high energy consumption in industry. This paper introduced saw dust (SD) to achieve physical viscosity reduction of OS, and then completed OS pyrolysis via steel slag (SS) with sufficient waste heat to replace external heat sources. The rotation of rotary kilns reactor with fins inside were utilized for pyrolysis, which exhibited excellent heat transfer effect for SS heating as validated by discrete element analysis (DEM) simulation. Temperature program and fixed temperature pyrolysis were respectively investigated and the latter one obtained higher yield of oil and gas. Especially SD addition increased the yield and quality of calorific value products (pyrolysis oil and gas). SS not only provided heat source but a lot had catalytic effect on pyrolysis, in which the [O] compounds provided by metal oxides could destroy the stability of chemical bond and deepen the cracking reaction. The energy equilibrium was calculated by heat capacity and reaction energy barrier. Finally, the pyrolytic residue was utilized as soil remediation agent by evaluating Ryegrass growth. Trace FeOx promoted photosynthesis and cellular respiration in plants, while excessive FeOx led to difficulty in respiration and decay of roots. Therefore, this new approach provides an alternative direction for collaborative treatment of OS, SD, and SS with co-benefits from three feedstocks to save energy and produce high-quality products of gas and oil.