化工进展 ›› 2020, Vol. 39 ›› Issue (9): 3810-3818.DOI: 10.16085/j.issn.1000-6613.2019-1943

• 资源与环境化工 • 上一篇    下一篇

O2浓度对污泥燃烧还原性气体产生及还原NO的双重影响

肖香1,2(), 方平1,2(), 黄建航1,2, 唐子君1,2, 吴海文1,2, 陈冬瑶1,2   

  1. 1.生态环境部华南环境科学研究所，广东 广州 510655
    2.广东省水与大气污染防治重点实验室，广东 广州 510655
  • 出版日期:2020-09-05 发布日期:2020-09-11
  • 通讯作者: 方平
  • 作者简介:肖香（1990—），女，硕士，助理研究员，研究方向为大气污染治理。E-mail：xiaoxiang@scies.org。
  • 基金资助:
    国家自然科学基金(NSFC-51778264);广东特支计划(2016TQ03Z576);广东省科技计划(2017B020237002);公益性科研院所基本科研业务专项(PM-zx703-201904-080)

Dual effects of O2 concentrationon reducing gases produced and NO reduced by sewage sludge combustion

Xiang XIAO1,2(), Ping FANG1,2(), Jianhang HUANG1,2, Zijun TANG1,2, Haiwen WU1,2, Dongyao CHEN1,2   

  1. 1.South China Institute of Environmental Sciences, The Ministry of Ecology and Environment, Guangzhou 510655, Guangdong, China
    2.The Key Laboratory of Water and Air Pollution Control of Guangdong Province, Guangzhou 510655, Guangdong, China
  • Online:2020-09-05 Published:2020-09-11
  • Contact: Ping FANG

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摘要：

在模拟水泥预分解炉装置上研究污泥燃烧过程中还原性气体的产生及其对NO的还原，并系统研究了O2浓度（体积分数为0～5%）对还原性气体产生及NO还原的双重影响。TG-FTIR特征分析表明，污泥燃烧产生的还原性气体主要为HCN、NH3、CO和CH4。进一步实验研究发现O2浓度对HCN和NH3的产生有明显影响，HCN和NH3在O2体积分数为3%时产生速率最大。同时，O2浓度对污泥燃烧还原NO有较大影响。在污泥燃烧温度为900℃，烟气中CO2体积分数为25%、NO浓度为600mg/m3、SO2浓度为200mg/m3、O2体积分数为3%时，NO还原率可达到最大（55.8%）。通过还原性物质（NH3、CO、CH4和污泥焦）对NO的还原实验研究进一步发现，NH3和CO是污泥燃烧过程中NO还原的关键物质，且NH3对NO的还原随着O2浓度的增加而增加，而CO对NO的还原受O2浓度的限制。综合分析表明，O2浓度对污泥燃烧NO还原的影响主要是由NH3的产生速率差异、NH3和CO对NO的还原起主导作用且受O2浓度影响较大等多种因素综合导致。采用污泥作为还原剂进行NO还原是一种高效的方法，在水泥生产中可通过控制O2浓度获得较高的NO还原率。

关键词: 污泥燃烧, 两相流, O2浓度, 气体, 还原

Abstract:

The reducing gases produced and NO reduction by sewage sludge combustion were investigated in a simulated cement precalciner. The dual role of O2 concentration (volume fraction is 0~5%) in the producing characteristic of reducing gases and the reduction of NO was studied systematically. Characteristic analysis of TG-FTIR demonstrated that the reducing gases produced by sewage sludge combustion were mainly HCN, NH3, CO and CH4. Further experimental studies showed that O2 concentration had pronounced effects on the distribution of HCN and NH3, and the maximum producing rate of HCN and NH3 was obtained at an O2 volume fraction of 3%. Meanwhile, O2 concentration had significant influence on the NO reduction by sewage sludge combustion. When the combustion temperature was of 900℃, the CO2 volume fraction of 25%, the NO concentration of 600mg/m3, the SO2 concentration of 200mg/m3, and the O2 volume fraction was 3%, respectively, the maximum NO reduction efficiency was achieved at 55.8%. The experimental studies on the NO reduction by reducing species (NH3, CO, CH4 and sludge char) further showed that NH3 and CO were the key species for NO reduction in the process of sewage sludge combustion, and the NO reduction by NH3 increased with the increase of O2 concentration, while the reduction performance of NO by CO was limited by O2 concentration. The comprehensive analysis showed that the effects of O2 concentration on NO reduction by sewage sludge combustion were mainly attributed to the difference in the producing rate of NH3, the dominant role of NH3 and CO in the reduction of NO and it was greatly affected by O2 concentration. Sewage sludge used as a reducing agent for NO reduction was efficient and a higher NO reduction efficiency was obtained by controlling the O2 concentration in cement production.

Key words: sludge combustion, two-phase flow, O2 concentration, gas, reduction

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