【摘要】：在國內(nèi)外近幾年的能源背景下,我國以煤炭為主體的能源供給格局在未來很長一段時間內(nèi)將不會改變。目前,許多火電廠鍋爐燃用非設(shè)計煤種,導(dǎo)致鍋爐燃燒不穩(wěn)定,燃燒效率下降,爐膛結(jié)渣等問題。因此,研究大容量超臨界機(jī)組鍋爐燃用非設(shè)計煤種安全性和經(jīng)濟(jì)性,拓寬鍋爐對燃燒煤種的適應(yīng)性,是目前火力發(fā)電行業(yè)亟需改進(jìn)或解決的重要研究課題。湖南某電廠地處湖南省邵陽市郊,燃煤主要采用邵陽周邊劣質(zhì)無煙煤與本地?zé)熋簱交?或與從外省采購的煙煤混配摻燒,運(yùn)行中很難保證鍋爐燃用設(shè)計煤種。為拓寬該電廠鍋爐對燃用非設(shè)計煤種的適應(yīng)性,本文針對該電廠660MW超臨界對沖鍋爐實(shí)際運(yùn)行過程燃煤的情況,挑選了最有可能燃用的20種單煤及15種混煤進(jìn)行爐內(nèi)燃燒的適應(yīng)性分析。首先,對選取的煤樣進(jìn)行工業(yè)分析、元素分析、發(fā)熱量等常規(guī)分析及熱重分析,了解各煤種的煤質(zhì)特性及燃燒特性,以此作為爐內(nèi)傳熱計算的基礎(chǔ)。之后,根據(jù)該電廠660MW超臨界鍋爐爐膛的設(shè)計尺寸、結(jié)構(gòu)特點(diǎn),建立傳熱計算數(shù)學(xué)模型,對原蘇聯(lián)的分區(qū)傳熱計算方法進(jìn)行改進(jìn)細(xì)化,把燃燒區(qū)域細(xì)分為三個區(qū)段,進(jìn)行改進(jìn)后的爐膛分區(qū)傳熱計算。通過計算得到在100%,75%,50%三種負(fù)荷情況下,燃用不同煤種時,沿爐膛高度的煙氣溫度及受熱面平均熱強(qiáng)度的分布情況。根據(jù)傳熱計算結(jié)果,結(jié)合各煤種的煤質(zhì)特性和燃燒特性,判斷得出在不同負(fù)荷下對鍋爐的適應(yīng)性較好煤種。同時,挑選出9個適爐煤種進(jìn)行了鍋爐熱態(tài)試驗驗證。通過現(xiàn)場試驗,驗證數(shù)學(xué)模型的準(zhǔn)確性,并結(jié)合測量的燃燒污染物排放和灰渣可燃物含量等因素,對煤種燃燒與鍋爐的適應(yīng)性進(jìn)行綜合性判斷。研究結(jié)果表明：所建立傳熱計算模型能合理反映出不同煤種在超臨界對沖火焰鍋爐爐內(nèi)燃燒的傳熱情況。在660MW.500MW、330MW三種負(fù)荷下,最適合鍋爐燃燒的煤種分別為發(fā)熱量大于18.5MJ/kg,9%Vdaf≤19%且C/H較大的武岡龍坪新礦煤、發(fā)熱量大于21.0MJ/kg,CM在20左右的混煤SS64和邵陽七里山老井煤。
[Abstract]:Under the background of domestic and foreign energy in recent years, the energy supply pattern with coal as the main body in our country will not change for a long time in the future. At present, many thermal power plant boilers burn non-designed coal, which results in unstable combustion, low combustion efficiency, slagging in furnace and so on. Therefore, to study the safety and economy of burning non-designed coal in large capacity supercritical unit boiler, and to broaden the adaptability of boiler to burning coal type, is an important research subject that needs to be improved or solved in the thermal power generation industry at present. A power plant in Hunan Province is located in the suburbs of Shaoyang City, Hunan Province. Coal burning is mainly mixed with inferior anthracite and local bituminous coal around Shaoyang, or mixed with bituminous coal purchased from other provinces. It is difficult to ensure boiler burning design coal in operation. In order to broaden the adaptability of the power plant boiler to burning non-designed coal, this paper aims at the case that the 660MW supercritical boiler in the power plant is used to hedge the actual operation process of the boiler. Twenty kinds of single coal and 15 kinds of mixed coal which are most likely to burn are selected to analyze the adaptability of combustion in furnace. Firstly, the industrial analysis, element analysis, calorimetric analysis and thermogravimetric analysis of the selected coal samples are carried out to understand the coal quality characteristics and combustion characteristics of each coal, which is used as the basis of heat transfer calculation in the furnace. Then, according to the design size and structural characteristics of the furnace of 660MW supercritical boiler in this power plant, the mathematical model of heat transfer calculation is established, and the calculation method of heat transfer in the former Soviet Union is improved and refined, and the combustion area is divided into three sections. The improved heat transfer calculation of furnace is carried out. The distribution of flue gas temperature and average heat intensity of heating surface along the furnace height is obtained by calculation under three kinds of loads of 100% 75% and 50%, when different kinds of coal are burned. According to the results of heat transfer calculation and combined with the coal quality characteristics and combustion characteristics of each kind of coal, it is concluded that the adaptability of coal to boiler is better under different loads. At the same time, 9 kinds of suitable coal were selected to verify the hot state of boiler. The accuracy of the mathematical model is verified by field test, and the adaptability of coal combustion to boiler is judged synthetically by combining the measured factors such as combustion pollutant discharge and ash and slag combustible content. The results show that the heat transfer calculation model can reasonably reflect the heat transfer of different kinds of coal combustion in supercritical flame boiler furnace. Under three kinds of loads of 660MW. 500MW / 330MW, the most suitable coal types for boiler combustion are the coal of Wugang Longping new coal mine, whose calorific value is greater than 18.5 MJ / kg ~ (9) V _ (daf) 鈮，

本文編號：2214283