摘 要
　　　
隨著電力工業(yè)的發(fā)展，火力發(fā)電機組的裝機容量日益增大，300MW、600MW 機組已成為電網(wǎng)中的主力機組，這部分機組運行質量的優(yōu)劣對整個電網(wǎng)運行的可靠性、經(jīng)濟性有著非常重要的影響。過熱器和再熱器作為鍋爐機組重要的部件，其可靠運行無疑對整個機組的安全運行有著非常重要的意義。隨著機組容量的增大，鍋爐過熱系統(tǒng)因熱偏差引起的超溫爆管事故頻頻發(fā)生，嚴重影響了發(fā)電廠的安全、經(jīng)濟運行。鑒于上述原因，關于熱偏差的成因及熱偏差、壁溫計算方法的研究就具有非常重要的實際意義。但多數(shù)人員對熱偏差成因的研究多側重于某一方面，很少對熱偏差的成因進行全面、系統(tǒng)的理論分析；而且我國許多鍋爐制造廠普遍采用原蘇聯(lián)熱力計算標準方法來計算壁溫，這種方法對于過去容量小、參數(shù)低的鍋爐機組來說，計算結果還比較準確，但是對于現(xiàn)代大容量、高參數(shù)的電站鍋爐來說，不可避免地帶來一些問題。因此，論文在關于熱偏差成因的綜合理論分析基礎之上，建立受熱面合理的蒸汽流量分配計算模型、熱偏差計算模型和壁溫計算模型，摒棄原有計算方法中的不足，采取適于工程應用的計算方法，以實現(xiàn)準確地反映受熱面出口汽溫和管子壁溫分布情況。同時，依據(jù)熱偏差的成因提出相應的減小措施或預防對策。
　　　
論文以吉林江南熱電330MW亞臨界鍋爐機組為例，對建立的計算模型進行了實際應用，對引起熱偏差的主要因素進行了分析。計算結果證明本文采用的計算方法較為合理，能夠反映受熱面的實際熱偏差狀況，對于過熱系統(tǒng)受熱面的優(yōu)化設計、事故分析提供了一定的參考價值和實際指導意義。
　　　
關鍵詞：鍋爐；過熱器；熱偏差；壁溫；超溫爆管


ABSTRACT
　　　
With the development of the electrical industry, the installed capacity of the thermal power generating unit is augmenting increasingly. The generating units of 300MW and 600MW have been the main ones in the power network. Whether these generating units′operation is superior or not will have a great influence on the dependability and efficient performance of the power network operation. The reliable operation of the superheater and reheater that are the key components of the large-capacity power station boiler is very significant for the whole units without doubt. With the enlargement of the installed capacity,the overheating and tube rupture of the boiler superheat system frequently happen because of thermal deviation, which seriously affects the safe and economy operation of generating plant.
　　　
On account of the related fact above, research into the causes of the thermal deviation, the calculation method of the thermal deviation and the wall temperature are greatly important. But most researches into the causes of the thermal deviation often are thrown into some a side, few carry out an all-round and systematic theoretical analysis, and many manufactures calculate the wall temperature popularly according to the old standard method about the heat calculation of the Soviet Union, this method is suitable for the last boiler unit of small capacity and low parameter, but as to large-capacity and high parameter power station boilers today, it will bring some problems inescapably. At the same time,according to the causes of the thermal deviation, the measures or schemes to decrease the thermal deviation have been put forward.
　　　
This dissertation puts the calculation patterns established into practical use, taking the thermal condition of the 330MW subcritical pressure concurrent boiler of the Jilin Jiangnan Power Plant as an example, and gives a profound analysis on the main causes of the thermal deviation. The calculation results of the thermal deviation prove it appropriate that the calculation method is taken, for the results can accord with the factual thermal deviation condition. So this dissertation can provide a certain reference value and practical direction for the optimum design of the heat-exchanger surface and the accident analysis.

Key words: Boiler；Superheater；Thermal deviation；Wall temperature；Overheating and tube rupture


目 錄
摘 要 I
ABSTRACT II
目 錄 III
第1章 緒 論 1
1.1 課題背景 1
1.2 國內外研究成果和發(fā)展動態(tài) 2
1.3 課題研究的內容與方法 3
第2章 過熱器系統(tǒng)的熱偏差理論分析 1
2.1 概述 4
2.2 過熱器熱偏差概念敘述 4
2.3 煙氣側熱偏差的原因 5
2.4 蒸汽側流量偏差原因 8
第3章 過熱器熱偏差基本計算方法 11
3.1 概述 11
3.2 熱負荷不均系數(shù)計算 11
3.3熱偏差計算相關參數(shù)的確定 14
3.4 并聯(lián)管組流量偏差計算 17
3.5 熱偏差系數(shù)計算 22
3.6 金屬壁溫計算 23
3.7 實例鍋爐介紹 25
3.8 實例應用計算結果 26
第4章 減小熱偏差的措施 29
4.1減小煙溫偏差的措施 29
4.2 減少蒸汽側偏差的措施 32
結 論 32
致 謝 33
參考文獻 36