With the rapid spread of renewable energy, pulverized-fired (PF) power plants are forced to participate in load cycling to ensure peak modulation and balance electricity demand and supply. The load fluctuation for PF power plants has led to a new focus problem in the study of NO_x formation and emission characteristics under off-design conditions. The difficulty in this study is due to the complex physical processes and large-scale research objects. An integrated simulation method is proposed to investigate the NO_x formation and removal processes of a 600 MW unit under off-design conditions systematically. The method combines the computational fluid dynamics (CFD) method, the boiler thermodynamic calculation method, and the NO_xremoval model. The CFD method is adopted to analyze the combustion and NO_x formation processes and obtain the NO_x formation value. The NO_x removal model is proposed to study the selective catalytic reduction (SCR) denitration process and calculate the NO_x removal efficiency accurately. At the operating condition of the SCR device, the boiler thermo-dynamic calculation method is used to calculate the flue gas temperature and velocity in each heat exchanger, including the economizer outlet (i.e., SCR inlet). The formation value of NO_x and its removal efficiency can facilitate the acquisition of the NO_x emission value. The temperature in the furnace decreased with the load, while the oxidizing atmosphere remained unchanged from the boiler maximum continue rate (BMCR) to the turbine heat acceptance (THA) condition and then increased from the THA to the 50% BMCR condition. The NO_x formation value decreased from 211 mg·m^-3 of BMCR to the lowest value (204 mg·m^-3) of THA and then increased to 245 mg-m-3 of 50% BMCR. The SCR inlet temperature and the flue gas flow rate decreased with the PF plant load reduction. The aforementioned factors coupled with the NO_x formation value initially decreased the NO_x removal efficiency from the BMCR to the THA condition but rapidly increased until the 50% BMCR condition. The NO_x emission value increased from 31.15 mg·m^-3 to 37.79 mg·m^-3 , 39.68 mg·m^-3, and 41.04 mg·m^-3 during the load reduction from BMCR to THA, 75% BMCR, and 50% BMCR conditions, respectively.

中文翻译：

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NO _X A的生成和排放特性600 MW机组下非设计工况

随着可再生能源的迅速普及，粉煤电厂被迫参与负载循环，以确保峰值调制并平衡电力需求和供应。对于PF电厂的负荷波动导致了NO的研究一个新的焦点问题_X的形成和发射特性非设计条件下。这项研究的困难是由于复杂的物理过程和大规模的研究对象。提出了一种综合模拟方法，系统地研究了非设计条件下600 MW机组的NO _x形成和去除过程。该方法结合了计算流体动力学（CFD）方法，锅炉热力学计算方法和NO _x删除模型。采用CFD方法分析燃烧过程和NO _x形成过程，并获得NO _x形成值。的NO _X去除模型提出来研究选择性催化还原（SCR）脱硝处理，并计算NO _X准确地去除效率。在SCR设备的运行条件下，使用锅炉热力学计算方法来计算每个热交换器（包括节能器出口（即SCR入口））中的烟气温度和速度。NO _x的形成值及其去除效率可以促进NO _x的获取排放值。炉内温度随负载而降低，而氧化气氛从锅炉最大持续速率（BMCR）到涡轮机热接受（THA）条件保持不变，然后从THA升高到50％BMCR条件。的NO _X形成值从211毫克下降·米^-3 BMCR的最低值（204毫克·米^-3）THA，然后提高到245毫克-M-3的50％BMCR。SCR入口温度和烟气流速随着PF设备负荷的减少而降低。前述因素与NO _x形成值结合最初使NO _x降低从BMCR到THA的去除效率，但迅速提高，直到BMCR达到50％。的NO _X排放值从31.15毫克增加·米^-3至37.79毫克·米^-3，39.68毫克·米^-3，和41.04毫克·米^-3从BMCR该负载减小到THA，75％BMCR和50中％BMCR条件分别。