化工进展 ›› 2023, Vol. 42 ›› Issue (9): 4947-4956.DOI: 10.16085/j.issn.1000-6613.2022-1862

• 资源与环境化工 • 上一篇    下一篇

污泥与聚氯乙烯共热解重金属特性

李志远1(), 黄亚继1(), 赵佳琪1, 于梦竹1, 朱志成1, 程好强1, 时浩1, 王圣2   

  1. 1.东南大学能源热转换及其过程测控教育部重点实验室,江苏 南京 210096
    2.清洁高效燃煤发电与污染控制国家重点实验室,江苏 南京 210023
  • 收稿日期:2022-10-08 修回日期:2022-11-25 出版日期:2023-09-15 发布日期:2023-09-28
  • 通讯作者: 黄亚继
  • 作者简介:李志远(1995—),男,博士研究生,研究方向为固体废弃物处理。E-mail:230218064@seu.edu.cn
  • 基金资助:
    江苏省科技计划(BE2022604)

Characterization of heavy metals during co-pyrolysis of sludge with PVC

LI Zhiyuan1(), HUANG Yaji1(), ZHAO Jiaqi1, YU Mengzhu1, ZHU Zhicheng1, CHENG Haoqiang1, SHI Hao1, WANG Sheng2   

  1. 1.Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, Jiangsu, China
    2.State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control, Nanjing 210023, Jiangsu, China
  • Received:2022-10-08 Revised:2022-11-25 Online:2023-09-15 Published:2023-09-28
  • Contact: HUANG Yaji

摘要:

重金属作为污泥热解处理过程中的主要污染物,对其进行严格的排放控制有益于生态环境和人类身体健康。本文通过在水平固定床反应器内开展城市污泥的快速热解实验,探究了温度(500~900℃)及聚氯乙烯塑料(PVC)掺混比(5%和15%)对重金属元素As、Cr、Cu、Mn、Ni、Pb和Zn在生物炭中迁移转化规律的影响。研究发现,提高热解温度和添加PVC有利于降低As、Pb和Zn在生物炭中的残余率,但对Cr、Cu、Mn和Ni几乎没有移除作用。此外,通过分析重金属赋存形态发现,伴随热解温度的升高,除了As以外,生物炭中的其他重金属元素整体向更稳定的形态转化。与此同时,根据重金属的生态风险评估结果发现,当热解温度为500℃和600℃时,原料中PVC的存在会增大所获取生物炭中重金属的生态风险。本文为实际工业热处理污泥提供了关于重金属排放控制方面有价值的参考。

关键词: 污泥, 聚氯乙烯塑料, 共热解, 重金属, 生态风险

Abstract:

As a major pollutant during sludge pyrolysis, strict emission control of heavy metals is beneficial to ecological environment and human health. To investigate the effects of temperature (500—900℃) and polyvinyl chloride plastic (PVC) blending ratio (5% and 15%) on the migration and transformation behaviors of heavy metals (As, Cr, Cu, Mn, Ni, Pb and Zn), pyrolysis experiments were conducted in a horizontal fixed-bed reactor. It was found that increased temperature and added PVC were beneficial to reduce the residual rate of As, Pb and Zn in biochar, but had almost no effect on the removal of Cr, Cu, Mn and Ni. In addition, the speciation analysis of heavy metals showed that with the increase of pyrolysis temperature, the overall conversions of heavy metals in biochar to more stable forms were observed, except for As. Meanwhile, based on the results of ecological risk assessment of heavy metals in biochar, it was found that the presence of PVC in the feedstock increased the ecological risk of heavy metals in the obtained biochar when the pyrolysis temperature was 500℃ and 600℃. This paper provided a valuable reference for actual industrial thermal treatment of sludge regarding the control of heavy metals emissions.

Key words: sludge, polyvinyl chloride plastic (PVC), co-pyrolysis, heavy metals, ecological risk

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