超临界电站锅炉热力计算及运行特性分析

论文总字数：69233字

摘 要

关键词：锅炉投入-产出软件；超临界；运行特性；VBA

Thermodynamic Calculation and Operation Characteristics analysis of Supercritical Power Plant Boiler

03013436 Yunfei Xie

Supervised by Xiaohu Xu

Abstract: The calculation of the heat (check) calculation of the boiler is one of the important steps in the process of boiler design and reconstruction. It is also one of the main methods to study the static and quasi-static process of the boiler. It is more important for the supercritical pressure boiler. Based on the latest calculation of boiler thermal calculation in 73 years, this paper establishes the modular calculation model of boiler thermal calculation based on the latest achievements of heat calculation of furnace and three-position rotary air conditioners in recent years. On the Excel software platform ,the data structure, module interface and iterative algorithm of boiler fuel calculation, heat balance calculation and thermal calculation of each heating surface are realized by using VBA and automation technology. A 600MW supercritical power plant boiler is taken as the object of study. The oxygen temperature and the temperature of the feed water are calculated, and the superheated steam temperature and the hot steam temperature characteristics of the boiler boiler are analyzed. The results show that with the increase of excess air coefficient, the flue gas temperature line rotates counterclockwise, the superheated steam temperature decreases, the reheat steam temperature rises, the air temperature rises, the flue gas flow rate increases, and the heat transfer coefficient decreases before and after the high The heating temperature and pressure rise, the convective heat absorption increases, the heat release of the flue gas decreases, the other heating surface rises, the thermal efficiency decreases, the exhaust gas temperature rises, and the steam temperature of the separator and the front screen decreases; , The superheated steam temperature rises, the reheat steam temperature rises and the steam temperature line increases in the divergence, the smoke temperature rises, the higher the smoke speed, the higher the heat transfer coefficient, the overall heat and temperature drop, the flue gas heat dissipation furnace, , With the overall increase in the air preheater, the overall increase in the heat efficiency, smoke, hot air, separator, front screen inlet temperature are rising; with the increase in coal heat, smoke, hot air temperature, front screen inlet temperature and separation The temperature rises, the temperature of the working fluid increases, the flue gas flow rate increases, the heat transfer temperature and pressure rise as a whole, the greater the heat release. From the BMCR operating conditions, THA operating conditions, 75% BMCR conditions, 50% BMCR down load, the thermal efficiency of the first rise and fall, the amount of coal decreased, the exhaust temperature dropped, the water temperature dropped, the excess air coefficient increased, Hot air temperature, separator temperature, the front screen inlet temperature are reduced phenomenon. At the same time, the calculation process also shows that the calculated software is correct, the algorithm is stable, the human-computer interaction is simple, the resources are small, the running speed is quick, the module is versatile, easy to expand and has high engineering practical value.

Key words: boiler input - output software; supercritical; operational characteristics; VBA

目 录

摘要 ………………………………………………………………………………………………………………………………………………………Ⅰ

Abstract ……………………………………………………………………………………………………………………………………………… Ⅱ

第一章 绪论 1

1.1超临界机组的现状及发展及其特性研究的必要性 1

1.2热力计算软件的发展及其必要性 1

1.3热力计算的特点 1

第二章 研究中遇到的热力计算问题及其研究对策 3

2.1热力计算中需要注意的地方 3

2.2放开汽温时热力计算方式的变化 6

第三章 VBA快速计算软件制作 7

3.1单级受热面的热力计算软件及迭代法的使用 7

3.2空气预热器的快速计算软件及二分法的运用 10

3.3减温水热力计算软件的开发与探索 11

3.4部分受热面之间的循环迭代 13

第四章 关于7个变量对5个误差的影响和热力计算程序设计思路的启示 14

4.1假设排烟温度改变 14

4.2假设热风温度改变 16

4.3假设前屏进口温度改变 19

4.4假设分离器温度改变 22

4.5假设减温水量改变 24

4.6假设过量空气系数变动 27

4.7汇总 29

第五章 投入产出模式软件的制作及软件的改进 34

5.1软件改进的思路 34

5.2软件的校验 39

5.2.1给水温度校验 39

5.2.2过量空气系数校验 40

5.3.3变负荷时的校验 41

5.3关于减温水的新思路 42

第六章 过量空气系数变化时运行特性分析 44

6.1过量空气系数的变动对烟温的影响 44

6.2过量空气系数对工质温度的影响 47

6.3过量空气系数对烟气流速的影响 50

6.4过量空气系数对传热系数K的影响 51

6.5过量空气系数对传热温压的影响 52

6.6过量空气系数对主受热面对流吸热量的影响 53

6.7过量空气系数对烟气放热量的影响 54

6.8小结 55

6.8.1烟气放热占比 55

6.8.2主要性能指标 55

第七章 给水温度变化时运行特性分析 57

7.1给水温度对烟温的影响 57

7.2给水温度对工质温度的影响 58

7.3给水温度对烟速的影响 60

7.4给水温度对传热系数K的影响 61

7.5给水温度对传热温压的影响 62

7.6给水温度对烟气放热量的影响 63

7.7给水温度对主受热面对流吸热量的影响 64

7.8小结 65

7.8.1烟气放热占比 65

7.8.2主要性能指标 66

第八章 煤质变化时运行特性分析 67

8.1煤种变化对烟温的影响 67

8.2煤种变化对工质温度的影响 69

8.3煤种对烟气流速的影响 71

8.4煤种对传热系数的影响 72

8.5煤种对传热温压的影响 73

8.6煤种对主受热面对流吸热量的影响 74

8.7煤种对烟气放热量的影响 74

8.8小结 75

第九章 负荷变化时主要参数与指标的变化 77

9.1流量与假设排烟温度对燃煤量的影响 77

9.2 600MW超临界机组调负荷时的一组模拟数据 79

9.3定温时50%BMCR工况下的另一组数据 81

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