Abstract

There are plans to do away with firing coal at the Kashira State District Power Plant (SDPP). In 2018, its coal-fired power units nos. 1 and 2 were decommissioned. Power unit no. 3, whose boiler can operate both on coal and natural gas, is being shifted to operate fully on natural gas, and fuel oil is supposed to be used as backup fuel. According to the design, the P-50R boiler, which is part of this power unit, can use fuel oil only as startup fuel during operation at loads up to 30%. In the article, the possibility of boiler operation on fuel oil in the entire working range of loads is substantiated. The boiler’s adaptive model has been developed using the Boiler Designer software and the experimental data obtained in the course of experiments on firing fuel oil. The results from numerical investigations have shown the possibility to use fuel oil as backup fuel in the P-50R boiler without modernizing its heating surfaces and draft equipment. It has been determined that it becomes possible to obtain a noticeably lower temperature of medium downstream of the middle radiant part, divided waterwalls, and further along the high-pressure path by admission of recirculation gases in an amount of around 180 000 m³/h (approximately 15% in the nominal mode). An analysis of the temperature operation conditions of radiant heating surfaces in firing fuel oil with such flowrate of recirculation gases has shown that reliable operation of all boiler heating surfaces is secured taking into account the scale formation condition and sufficient mechanical strength safety margin in the load range 100–60%. It has been determined that an essentially larger flowrate of medium goes through the steam-to-steam heat exchanger (SSHE) bypass in the entire design range of loads during operation with recirculation of gases. Therefore, the reheat steam temperature at a level of 545°C can be achieved even at decreased loads. The use of gas recirculation as a technological method for suppressing the generation of nitrogen oxides in the P-50R boiler makes it possible to keep the NO_х concentrations in the fuel oil combustion products in compliance with the relevant regulations (less than 250 mg/m³). It has been determined from the calculation results that admission of recirculation gases in an amount of 180 000 m³/h does not have a significant influence on the economic indicators of boiler operation.

中文翻译：

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在喀什拉邦地区电力计划中，证明在P-50R燃煤锅炉中燃烧燃料油作为备用燃料的可能性

摘要

喀什拉邦州发电厂（SDPP）计划取消燃煤。2018年，其燃煤电厂 1和2已退役。动力单元编号 3，其锅炉既可以使用煤也可以使用天然气，但现在已转换为完全使用天然气，并且应该将燃油用作备用燃料。根据设计，作为该动力装置一部分的P-50R锅炉只能在最高30％的负载下运行期间使用燃油作为启动燃料。在本文中，证实了在整个负载范围内锅炉运行燃油的可能性。使用Boiler Designer软件开发了锅炉的自适应模型，并在燃烧燃油的实验过程中获得了实验数据。数值研究的结果表明，可以在不对加热面和通风设备进行现代化改造的情况下，将燃油用作P-50R锅炉的备用燃料。已经确定，通过吸收大约180000 m的再循环气体，可以使中间辐射部分下游，分隔的水冷壁以及沿着高压路径的介质温度明显降低。³/ h（在正常模式下约为15％）。对具有这种再循环气体流量的燃料油中的辐射受热面的温度运行条件的分析表明，考虑到水垢形成条件和在负载范围内足够的机械强度安全裕度，可以确保所有锅炉受热面的可靠运行100–60％。已经确定，在气体循环操作期间，在负载的整个设计范围内，基本上更大的介质流量会通过蒸汽-蒸汽热交换器（SSHE）旁路。因此，即使在减少负荷的情况下也可以达到545℃的再热蒸汽温度。使用气体再循环作为抑制P-50R锅炉中氮氧化物生成的技术方法可以保持NO燃油燃烧产物中的_х浓度符合相关规定（低于250 mg / m ³）。从计算结果已经确定，流入180 000 m ³ / h的再循环气体对锅炉运行的经济指标没有重大影响。