本文選題：脫硫廢水 + 零排放�。� 參考：《浙江大學》2017年碩士論文

【摘要】：近年來,我國燃煤電廠脫硫廢水零排放已得到廣泛重視。其中煙道噴霧蒸發(fā)技術因具有占地面積小、工藝簡單、改造費用低等優(yōu)點而受到廣泛關注,但目前此技術尚未成熟,廢水量過大可能導致廢水回噴煙道后的積灰及腐蝕等問題。當煙氣中的HCl被大量脫除后,脫硫廢水排放率將大幅度減少。為解決廢水煙道噴霧蒸發(fā)技術中因廢水量過大導致的問題,本文創(chuàng)新性地提出了一種半干法脫氯技術,即首先脫除煙氣中的HCl,大幅度減少脫硫廢水量,再將脫硫廢水作為堿基溶劑回噴到煙氣中,實現(xiàn)脫硫廢水零排放。利用CHEMKIN軟件對半干法脫氯過程進行了化學動力學模擬,研究了在燃煤電廠煙氣氣氛中,NaOH與HCl、SO2、SO3的反應過程與程度;搭建實驗臺模擬空預器至除塵器間煙道,研究了 Na/Cl、HF、堿基種類、S02濃度、煙溫及停留時間對HCl反應效率的影響。并得出以下結論:HCl的反應效率與Na/Cl呈正相關,隨著Na/Cl的增大,HCl的反應效率逐漸升高,但Na/Cl5后增長趨勢逐漸變緩;S02的反應效率隨Na/Cl的增大近線性上升;煙氣中HF的存在對半干法脫氯過程的影響較小;煙氣中SO2對HCl的脫除過程有一定干擾作用,但HCl的反應效率依然處于較高水平,Na/Cl 一定時,SO2的濃度每變化1000mg/Nm3,HCl的反應效率變化約13%,對某臺特定鍋爐而言,SO2濃度一般僅在小范圍內變化,不會對HCl的反應效率的穩(wěn)定性造成太大影響;堿基物質對HCl的脫除效果與其堿性強弱有關,堿基物質按脫除效果強弱排列依次為NaOH,Na2CO3,NaHCO3;煙溫的變化將顯著影響半干法脫氯的反應效率,隨著溫度由100℃C上升到140℃,HCl的反應效率逐漸下降,由78.67%下降到59.23%;隨著停留時間由0.5s延長至2.5s,HCl的反應效率有輕微幅度的上升,由68.13%上升至73.01%。通過對一臺660WM機組進行分析計算,研究了半干法脫氯后脫硫廢水量、廢水回噴后的煙氣溫降、運行經(jīng)濟性及對粉煤灰利用的影響。通過計算可知半干法脫氯后,脫硫廢水量顯著降低71.16%。此時將廢水回噴煙道,煙氣溫降較小,僅為2.49℃。半干法脫氯系統(tǒng)簡單,成本較低,不會對粉煤灰的綜合利用造成顯著的不利影響。
[Abstract]:In recent years, zero discharge of desulfurization wastewater from coal-fired power plants has been paid more and more attention. The flue spray evaporation technology is widely concerned because of its advantages of small area, simple process and low cost of renovation. However, at present, the technology is not yet mature, and too much waste water may lead to ash deposition and corrosion after the waste water is returned to the flue. After the removal of HCl from flue gas, the discharge rate of desulfurization wastewater will be greatly reduced. In order to solve the problem caused by excessive amount of waste water in flue spray evaporation of waste water, a semi-dry dechlorination technology is proposed in this paper, that is, the HCl in flue gas is removed first, and the amount of waste water in desulfurization is greatly reduced. The desulphurization wastewater was injected back into the flue gas as base solvent to realize zero discharge of desulfurization wastewater. The chemical kinetics simulation of semi-dry dechlorination process was carried out by using CHEMKIN software, the reaction process and degree of NaOH and HClNSO _ 2so _ 3 in the flue gas atmosphere of coal-fired power plant were studied, and the flue gas between the air preheater and the dust collector was simulated by an experimental bench. The effects of the concentration of Na / Cl-HF, base species S02, smoke temperature and residence time on the HCl reaction efficiency were studied. The following conclusions are drawn: the reaction efficiency of Na/Cl is positively correlated with the reaction efficiency of Na/Cl, and increases gradually with the increase of Na/Cl, but the reaction efficiency of S02 increases linearly with the increase of Na/Cl after Na/Cl5. The presence of HF in flue gas has little effect on the process of semi-dry dechlorination, and SO2 in flue gas has a certain interference effect on the process of HCl removal. However, the reaction efficiency of HCl is still at a high level. When the concentration of so _ 2 varies by 1000mg / Nm _ 3H _ 2HCl, the reaction efficiency of so _ 2 is about 13%. For a particular boiler, the concentration of so _ 2 generally changes only in a small range. The stability of the reaction efficiency of HCl will not be greatly affected, and the removal effect of base material on HCl is related to its alkalinity. In order of removal effect, NaOHN Na2CO3 + NaHCO3, the change of smoke temperature will significantly affect the dechlorination efficiency of semi-dry process, and the reaction efficiency will decrease with the increase of temperature from 100 鈩，

本文編號：1882244