摘要
针对在流化床中密相区的气固流动行为与污染物NO_(x)之间关系规律和影响机制的问题,本文借助鼓泡流化床反应器,研究了准东煤和柏木在不同床内温度、流化风速和给料速率条件下燃烧时烟气中NO_(x)的浓度,并利用功率谱密度分析法分析了流化床内气固流态。结果表明,随着温度的升高,床内流化气体密度降低,使得床内截面气速增加,鼓泡流态化更加剧烈,促进了气固混合与接触,从而使烟气中NO_(x)含量显著增大。适当提高流化风速,有利于床层形成充分的鼓泡流态化,使燃料燃烧更加充分,但流化风速过大,也会导致烟气中NO_(x)排放浓度上升。通过降低给料速率,会导致床层高度降低,抑制鼓泡流态化的充分发展,减弱气固混合和接触的强度,产生还原性气氛,使得NO_(x)浓度降低。该研究对进一步优化循环流化床炉内气固流动状态,降低NO_(x)的排放具有重要意义。
To address the issue of the relationship law and influence mechanism between the gas-solid flow behavior in the dense phase zone in fluidized bed and the pollutant NO_(x),this paper investigates the concentration of NO_(x) in the flue gas of quasi-east coal and cypress during combustion at different in-bed temperatures,fluidization air velocities and feed rates with the aid of a bubbling fluidized bed reactor,and analyzes the gas-solid flow pattern in the fluidized bed using power spectrum density analysis.The results show that:with the increase of temperature,the density of fluidized gas in the bed decreases,which makes the gas velocity in the bed section increase and the bubble fluidization become more intense,which promotes the gas-solid mixing and contact,thus the NO_(x) content in the flue gas increases significantly;appropriately increasing the fluidization wind speed is beneficial to the formation of sufficient bubble fluidization in the bed,which makes the fuel burn more fully,but too large fluidization wind speed also leads to the NO_(x) emission concentration in the flue gas However,too high fluidization air speed will also lead to the increase of NO_(x) emission concentration in flue gas;reducing the feed rate will lead to the decrease of bed height,inhibit the full development of bubble fluidization,weaken the intensity of gas-solid mixing and contact,and produce reducing atmosphere,which makes the NO_(x) concentration decrease.This study is important to further optimize the gas-solid flow state in the circulating fluidized bed boiler and reduce NO_(x) emissions.
作者
邓尚致
姜华伟
聂茂峰
黄玉林
张洪玮
郭庆杰
王翠苹
DENG Shangzhi;JIANG Huawei;NIE Maofeng;LI Ye;HUANG Yulin;ZHANG Hongwei;GUO Qingjie;WANG Cuiping(College of Mechanical and Electrical Engineering,Qingdao University,Qingdao 266071,China;State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China;College of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,China)
出处
《青岛大学学报（工程技术版）》
CAS
2022年第2期88-94,共7页
Journal of Qingdao University(Engineering & Technology Edition)
基金
省部共建煤炭高效利用与绿色化工国家重点实验室开放课题(2018-K17)
国家级大学生创新创业训练计划(201811065028)。
关键词
鼓泡流化床
气固流态化
氮氧化物
压力波动
污染物排放
bubbling fluidized bed
gas solid fluidization
nitrogen oxides
pressure fluctuation
pollutant discharge
