小型热电厂实现超低排放改造技术路线应用与研究

发布时间：2018-01-11 19:17

本文关键词：小型热电厂实现超低排放改造技术路线应用与研究　出处：《青岛理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：在国家大气污染物排放标准逐年严格的情况下,大气污染物实现超低排放是燃煤热电企业当前普遍面临的新挑战。本文针对青岛热电股份公司4台75t/h煤粉锅炉现有设备及特点,进行脱硝、除尘及脱硫工艺的技术路线研究,确定最佳改造方案,实现超低排放目标,对小型热电企业环保改造具有重要指导意义。通过研究得到以下结论:(1)针对燃用贫煤,热风送粉小型煤粉锅炉,充分分析了煤种变化,制粉系统启停及燃烧器对氮氧化物生成浓度的影响。根据分析结果确定了贫煤改烧烟煤,热风送粉改为乏气送粉的技术改造路线,NOx生成浓度由550mg/Nm3降至350mg/Nm3。通过改造不仅能从源头减少NOx生成,并且有利于减少后续烟气中NOx污染物治理成本及难度。(2)烟气中NOx治理最优选择方案为SCR技术,脱硝效率达到85%以上,达到NOx浓度小于50 mg/Nm3的超低排放标准。(3)对于此热电厂高浓度烟尘及老旧电除尘器实现超低排放目标,改为电袋复合除尘器是最佳手段,可使除尘器出口浓度达到20mg/Nm3以下,配合湿式电除尘器实现烟尘排放小于10mg/Nm3。(4)针对原双碱法脱硫系统,在保留双碱法优点及节省投入资金的情况下,进行系统优化改造,实现SO2排放浓度小于35mg/Nm3。先进有效的设备系统是实现超低排放的重要前提,科学细致的运行调整是实现超低排放的重要保证,对于炉内低氮燃烧,SCR脱硝系统,双碱法脱硫氧化再生及塔内喷淋等方面精细、严谨的运行调整至关重要。在这些方面仍需通过运行实践总结规律,研究如何利用自动调节、智能控制实现超低排放的目标。
[Abstract]:Under the circumstance that the national air pollutant discharge standard is strict year by year. The realization of ultra-low emission of atmospheric pollutants is a new challenge to coal-fired thermal power enterprises. This paper aims at the existing equipment and characteristics of four 75 t / h pulverized coal boilers in Qingdao Thermal Power Co., Ltd. The technical route of dust removal and desulphurization process is studied to determine the best retrofit scheme and to realize the ultra-low emission target. It is of great guiding significance to the environmental protection reform of small thermal power enterprises. The following conclusions are obtained: (1) aiming at the small pulverized coal boilers burning lean coal and hot air pulverized coal, the change of coal types is fully analyzed. Starting and stopping of pulverizing system and influence of burners on the concentration of nitrogen oxides. According to the analysis results, the technical transformation route of lean coal to bituminous coal and hot air powder to spent gas powder was determined. The concentration of NOx is reduced from 550 mg / Nm3 to 350 mg / Nm3. Not only can the NOx generation be reduced from the source. And it is helpful to reduce the cost and difficulty of NOx pollution treatment in the follow-up flue gas.) the best solution for NOx treatment in flue gas is SCR technology, and the denitrification efficiency is more than 85%. To achieve the ultra-low emission standard of NOx concentration less than 50 mg/Nm3.) to achieve the ultra-low emission target for high concentration soot dust and old electrostatic precipitator in this thermal power plant. It is the best method to change to the electric bag composite dust collector, which can make the outlet concentration of the dust collector under 20mg / Nm3. Combined with wet electrostatic precipitator to realize smoke emission less than 10 mg / Nm 3. 4) aiming at the original double alkali desulphurization system, the system was optimized under the condition of keeping the advantages of double alkali process and saving investment. The realization of SO2 emission concentration less than 35mg / Nm3.Advanced and effective equipment system is an important prerequisite to achieve ultra-low emissions, scientific and meticulous operation adjustment is an important guarantee to achieve ultra-low emissions. For the SCR denitrification system of low nitrogen combustion in the furnace, the regeneration of double alkali desulfurization and oxidation and the spray in the tower are very fine, and the strict operation adjustment is very important. In these aspects, we still need to sum up the rules through the operation practice. This paper studies how to use automatic regulation and intelligent control to achieve the goal of ultra-low emission.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X773;TM621

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