共查询到20条相似文献,搜索用时 171 毫秒
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在喷射器辅助供热的背景下,为了研究喷射器变工况特性,对国内外有关喷射器的计算方法进行调研,建立了喷射器计算模型并将模型与高背压机组进行耦合,得到喷射器变工况时工作蒸汽、引射蒸汽、喷射器背压、喷射器开度对喷射器性能的影响。结果表明:喷射器工作流体压力从0.25 MPa增至0.45 MPa,工作流体质量流量先变大后变小,在工作蒸汽压力为设计工作蒸汽压力时喷射器性能最佳;引射蒸汽压力提高,临界背压提高;引射后的混合流体的压力不仅会影响喷射器的工作,也会影响凝汽器工作;相比抽背机组,高背压耦合喷射器机组低压缸最小冷却流量最大可降低140 t/h,供电范围提高43 MW。 相似文献
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某电厂真空泵在运行中存在噪声大、振动较大、真空度不高和汽蚀较严重的现象,为此提出对真空泵加装前置式大气喷射器的改造建议。结果表明:加装前置式大气喷射器后,消除了噪声和振动,提高了真空泵的极限抽吸压力,防止了真空泵汽蚀,起到了保护真空泵的作用,保证了机组真空系统安全稳定运行。 相似文献
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本文从节能角度介绍300MW汽轮机组给水泵驱动汽轮机低压喷嘴、给水泵机械密封、高低压加热器疏水系统、凝升泵叶轮切削、轴封抽汽系统及加热器等的故障分析和改进情况。 相似文献
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国电达州发电有限公司300MW汽轮机组在运行中存在真空低的问题,原因是由于汽动给水泵密封水系统在设计安装上与汽泵制造厂要求存在差异,以及在运行调节方式上的不合理,造成汽动泵U形水封在运行时封不住使空气漏入凝汽器,导致机组真空降低。电厂为维持较高真空则将密封水排放掉,使工质流失,增加机组热耗率。采取了对该系统设备和密封水差压调节方式进行改造等措施,使机组真空得到了改善,实现密封水全额回收,并提高了机组热效率和安全、经济性。 相似文献
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阐述了射汽抽气器、射水抽气器和机械式水环真空泵的工作特点和特性分析,为选择抽气装置给出了理论根据。 相似文献
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为降低厂用用电率,四川广安电厂在机组启停过程中以汽动给水泵代替电动给水泵,但在实际运行中遇到了辅助蒸汽疏水不畅和压力不够大、给水泵汽轮机受到热冲击等问题。为此,从实际出发提出了一系列解决问题的措施:增加低压辅助蒸汽管道以加强疏水,通过提高邻机负荷或邻机高压辅助蒸汽带低压辅助蒸汽联箱来提高低压辅助蒸汽压力,切断高压进汽管道,直接由低压汽源供汽来减小给水泵汽轮机的热冲击。措施实施后,广安电厂4台300MW机组2008年启停28次,节约厂用电约60MWh。 相似文献
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K. E. Aronson A. Yu. Ryabchikov Yu. M. Brodov D. V. Brezgin N. V. Zhelonkin I. B. Murmanskii 《Thermal Engineering》2017,64(2):104-110
A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the “sound tube” zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the “sound tube” define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70–80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector’s mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime. 相似文献
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G. V. Ledukhovsky Yu. E. Barochkin V. P. Zhukov V. N. Vinogradov I. A. Shatova 《Thermal Engineering》2018,65(10):751-755
Results of experimental investigations performed on 210–1200 MWel. power units at thermal and nuclear power stations yielded a statistical correlation of the corrosion rate for cooled copper conductors in water-cooling systems of the stator winding in a hydrogen-water cooled generator vs. cooling water quality characteristics, such as electrical conductivity, pH, and dissolved oxygen content. The content of dissolved oxygen in the cooling water is found to have a pronounced effect on the efficiency of corrosion protection of system elements. An engineering solution is proposed. It calls for installation of a small cavitation deaerator operating on superheated water in the cooling water return pipeline from the turbogenerator stator winding to a vacuum tank from which steam is removed by the main ejector of the turbine unit condenser or the deaerator’s own ejector. Special experimental investigations allowed the determination of the water deaeration efficiency in deaerators of the considered type. It is described by a dependence of a relative decrease in the content by weight of oxygen dissolved in the deaerated water on the water overheating at the deaerator inlet with reference to saturation temperature corresponding to the pressure in the steam suction pipeline. It was established by calculations that the proposed engineering solution decreased the corrosion rate of copper conductors in water-cooling systems of the stator winding, on average, by a factor of 2.1. Results of this investigation can be used in designing new power facilities or retrofitting process systems of operating hydrogen-water cooled turbogenerators. 相似文献
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利用辅汽暧炉技术,实现机组的冷态启动,可挖掘电厂的节能潜力。具体实施方法是在锅炉点火前,将邻机辅汽导入,辅汽对沿途经过的受热面进行加热,同时,通过除氧器加热给水,逐渐提到了锅炉进水温度,完成对锅炉省煤器、包覆管、水冷壁、汽包以及水系统联箱的预暖和升温。给水温度的提高,也使汽包温度随之升高。利用这种暧机方法,已在2号机组的冷态启动中,取得了较为满意的节能效果。 相似文献