【摘要】：現(xiàn)有的火力發(fā)電技術(shù)面對(duì)著社會(huì)、資源和經(jīng)濟(jì)等多方面的壓力,進(jìn)一步研究和發(fā)展更加環(huán)保低耗的火力發(fā)電技術(shù)是解決以后火電發(fā)展問(wèn)題的最佳選擇。面對(duì)我國(guó)社會(huì)和科技的飛速發(fā)展,各個(gè)行業(yè)的電力需求和環(huán)保的壓力對(duì)我國(guó)節(jié)能減排有了更高的標(biāo)準(zhǔn)。更深層次地研究和優(yōu)化機(jī)組的各項(xiàng)運(yùn)行參數(shù),對(duì)實(shí)現(xiàn)機(jī)組降低平均煤耗率具有重要意義。現(xiàn)代大型火電機(jī)組運(yùn)行較為復(fù)雜,以某N1000-32.1/600/620/620機(jī)組為例進(jìn)行研究。基于汽輪機(jī)、凝汽器、循環(huán)水系統(tǒng)及給水系統(tǒng)的變工況算法分別以機(jī)組熱耗率最小、機(jī)組功率變化量與循環(huán)水泵耗功之差最大及全廠供電效率最高為目標(biāo)函數(shù),建立了主蒸汽壓力、排汽壓力及以供電效率最高為優(yōu)化目標(biāo)函數(shù)的運(yùn)行參數(shù)優(yōu)化模型,以確定機(jī)組的最優(yōu)運(yùn)行參數(shù)。計(jì)算結(jié)果表明:在主蒸汽壓力優(yōu)化中,機(jī)組配置的調(diào)節(jié)閥個(gè)數(shù)較少,調(diào)節(jié)閥門(mén)產(chǎn)生的節(jié)流損失對(duì)機(jī)組的熱耗率影響較大。通過(guò)比較一閥全開(kāi)一閥節(jié)流、兩閥滑壓節(jié)流配汽和純滑壓運(yùn)行三種配汽方式下機(jī)組熱耗率的變化可知,在滿(mǎn)足機(jī)組負(fù)荷條件下,一閥全開(kāi)一閥節(jié)流配汽優(yōu)于純滑壓運(yùn)行和兩閥滑壓節(jié)流配汽。機(jī)組在同一負(fù)荷下的最優(yōu)值略大于設(shè)計(jì)值,同時(shí)優(yōu)化熱耗率也比設(shè)計(jì)值略低。在變工況運(yùn)行區(qū)域內(nèi),通過(guò)主蒸汽壓力的改變使機(jī)組的熱經(jīng)濟(jì)性達(dá)到最好,從而獲得機(jī)組實(shí)際運(yùn)行的最優(yōu)主蒸汽壓力曲線。在排汽壓力和循環(huán)水泵運(yùn)行參數(shù)優(yōu)化中,在某一給定循環(huán)水溫度下,當(dāng)機(jī)組功率升高時(shí),最優(yōu)循環(huán)水泵流量和最優(yōu)排汽壓力均有所升高;在機(jī)組某一給定負(fù)荷下,當(dāng)循環(huán)水溫度低于10℃或高于20℃時(shí),冷卻水溫度對(duì)排汽壓力的影響較為明顯,且機(jī)組功率增量變化較大。當(dāng)循環(huán)水溫度為30℃時(shí),為盡量降低凝汽器壓力,循環(huán)水泵流量基本達(dá)到最大值8866kg/s。在以供電效率最大為目標(biāo)函數(shù)的運(yùn)行參數(shù)優(yōu)化中,在給定某一機(jī)組功率的前提下,隨著循環(huán)冷卻水溫度的升高,最優(yōu)主蒸汽壓力、排汽壓力、循環(huán)水流量都有所升高,且由于電動(dòng)循環(huán)水泵和汽動(dòng)給水泵的耗功增加,使全廠的供電效率降低。以85%負(fù)荷為例,當(dāng)循環(huán)水溫度從5℃上升到30℃時(shí),供電效率依次為45.26%、45.13%、45.08%、45.03%、44.95%、44.89%,其中最高值與最低值相差為0.37%。因此機(jī)組在運(yùn)行時(shí)要盡量降低循環(huán)水溫度,保證獲得較好的熱經(jīng)濟(jì)性。
[Abstract]:The existing thermal power generation technology is facing social, resource and economic pressures. Further research and development of more environmentally friendly and low-consumption thermal power generation technology is the best choice to solve the problem of thermal power development in the future. Facing the rapid development of our society and science and technology, the demand for electricity and the pressure of environmental protection in various industries have a higher standard for energy saving and emission reduction in China. It is of great significance to study and optimize the operation parameters of the unit in a deeper level to reduce the average coal consumption rate of the unit. The operation of modern large thermal power generating units is more complicated, taking a N1000-32.1 / 600 / 620 / 620 unit as an example. Based on the variable working condition algorithms of steam turbine, condenser, circulating water system and feed water system, respectively, the minimum heat consumption rate of the unit, the biggest difference between the unit power change and the power consumption of the circulating water pump and the highest power supply efficiency of the whole plant are the objective functions. The optimization models of main steam pressure, exhaust steam pressure and operation parameters with the maximum power supply efficiency as the optimization objective function are established to determine the optimal operating parameters of the unit. The results show that in the optimization of the main steam pressure, the number of regulating valves is small, and the throttling loss caused by the regulating valves has a great influence on the heat consumption rate of the units. By comparing the change of heat consumption rate of the unit under three steam distribution modes of one valve, two valve sliding pressure throttling and pure sliding pressure operation, it can be seen that the heat consumption of the unit can be satisfied under the condition of unit load. The throttling distribution of one valve is superior to that of pure sliding pressure operation and two valve sliding pressure throttling steam distribution. The optimum value of the unit under the same load is slightly larger than the design value, and the optimized heat consumption rate is also slightly lower than the design value. The thermal economy of the unit is best through the change of the main steam pressure in the operation area of the variable working condition, and the optimal main steam pressure curve of the unit is obtained. In the optimization of exhaust steam pressure and circulating pump operating parameters, under a given circulating water temperature, the optimal circulating pump flow rate and optimal exhaust steam pressure are increased when the unit power is increased, and at a given load of the unit, the optimal circulating pump flow rate and the optimal exhaust steam pressure are increased. When the circulating water temperature is lower than 10 鈩，

本文編號(hào)：2141434