双背压凝汽器抽真空系统布置方式的研究

STUDY ON ARRANGEMENT MODE FOR AIR-EXTRACTING SYSTEM OF THE DUAL-BACKPRESSURE CONDENSER

根据双背压凝汽器抽真空系统的不同布置方式,并结合实例分析研究其对双背压凝汽器高、低压差值的影响。结果表明,串联布置方式的优点是系统简单、投资小,但易造成双背压凝汽器的高、低压力不能同时达到设计值,甚至无高、低压差值;并联布置方式的系统相互独立,凝汽器压力和传热端差均可达到设计要求。建议新建机组的抽真空系统按照并联布置方式设计,投运机组可考虑优化改造为并联布置方式,以充分发挥双背压凝汽器的技术和经济性优势。

Based on different arrangement modes of air - extracting system for dual - backpressure con- denser,and combined with analysis of practical examples, the influence of arrangement mode for airextracting system upon the difference value between high - pressure and low - pressure of the dual - backpressure condenser has been analysed and studied, results show that the advantage of series connection mode is little capital investment, but it is easy to make the high -pressure and lowpressureof dual-backpressure condenser can＇t reach the designed values at the same time,and even result in without pressure difference between high - pressure and low - pressure. In parallel connection mode, the high-pressure and low pressure system is mutually separated, the pressure in condenser and the terminal temperature difference in heat transfer, all can reach the requirments of design. It is recomended that the air - extracting system of newly constructed units should be designed according to the par- allel connection mode, the units already in operation can be considered to optimize and retrofit into parallel connection mode,so as to give full play to the superiority of technological and economic advantages of the dual - backpressure condenser.