摘要：电力工业是国民经济发展的基础工业，电力工业的发展水平和电能供应的数量和质量是衡量工业、农业、国防和科技现代化水平的重要标准。
本设计以发电厂安全、经济运行为目标，采用物质平衡和能量平衡的计算方法，针对CC50—8.82/1.275/0.118型供热机组提出了五种原则性热力系统计算方案，通过每种方案主要热经济指标的比较，选择出最佳方案。
方案一中的热力系统设有两级排污扩容器，有高压除氧器（HD），补充水除氧器（MD）。HD抽汽来自第二级抽汽，MD抽汽来自第四级抽汽，HD排气送到冷却器。MD抽汽来自第四级抽汽，HD排气送到冷却器，MD排气送到H4，五级回热系统，设有抽汽冷却器和轴封冷却器。
其他四个方案均在此基础上做了一些改动，已获得更好的系统热经济性或减少初投资。方案二中考虑了初投资问题，省去了补充水除氧器，但系统运行费用增高，减少了投资，但能量损失加大。方案三中采用了一级连续排污扩容器，方案四中采用了疏水逐级自流代替疏水泵运行方式。方案五中将采暖回水用泵泵入M2混合器中，增加了初投资但提高了系统的热经济性。经计算得出方案五为最佳方案。
Abstract：The electric power industry is the basic industries of national economy development, the electric power industry level of development and electrical energy supply quantity and the quality are the weight industry, agricultural, the national defense and the technical modernization level important standard.
This design takes the power plant security, the economical movement as a goal, uses the matter balance and the energy balance computational method, proposed in view of the CC50—8.82/1.275/0.118 heating units five kinds of principled thermodynamic system numerical procedure, through each kind of plan in the different time thermal power plant main hot economic indicator's comparison, chooses the good plan.
The first design include two-grade expanding volume apparatuses，two high-pressure heating apparatuses,three low-pressure heating apparatuses and two apparatus which removes gas such as oxygen carbon-dioxide in the apparatus,stream interring HD is from pump and stream exhaled from MD is to H4.
Comparing with the first project，in the second project used one grade expanding-volume apparatus.So the money can be saved.For the same reason,the third project use one-apparatus which can remove gas from itself(MD).In the forth project adopts that the water fluidizes from the first apparatus to the fifth apparatus one by one so the capital investment.
