本文關(guān)鍵詞：鈉堿法煙氣脫硫廢水回收利用研究　出處：《東北石油大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 鈉堿法 含鹽脫硫廢水 回收利用 機(jī)械蒸汽再壓縮 冷凍結(jié)晶

【摘要】：鈉堿法煙氣脫硫即將NaOH(或Na2CO3)溶液直接加入吸收塔,吸收廢氣中的SO2。與傳統(tǒng)的石灰石/石膏法相比,鈉堿法脫硫效率高、結(jié)垢現(xiàn)象少、副產(chǎn)物無二次污染等優(yōu)點(diǎn)。該法所產(chǎn)生的脫硫廢水無機(jī)鹽物質(zhì)含量超過1%,屬于高含鹽廢水。此類廢水直接排放將會(huì)使周邊土壤、水體的含鹽量升高從而對(duì)環(huán)境產(chǎn)生破壞,同時(shí)還浪費(fèi)了資源。實(shí)現(xiàn)工業(yè)生產(chǎn)過程中高含鹽廢水排放量最小化或零排放,對(duì)環(huán)境保護(hù)具有重要的意義。本文研究對(duì)象為某熱電廠鈉堿法煙氣脫硫廢水,對(duì)該廢水進(jìn)行水質(zhì)分析知該廢水主要成分為無機(jī)鹽類,其中Na2SO4含量最高在40~60 g/L之間。由此可知,應(yīng)采用物理方法對(duì)該廢水進(jìn)行濃縮處理,將無機(jī)鹽和水進(jìn)行分離后分別加以回收利用。結(jié)合脫硫廢水含鹽量較高的特點(diǎn)及對(duì)幾種高含鹽廢水的物理處理技術(shù)在經(jīng)濟(jì)、技術(shù)、環(huán)保等方面進(jìn)行比較分析可知,機(jī)械蒸汽再壓縮蒸發(fā)技術(shù)(MVR)在濃縮處理該高含鹽脫硫廢水方面更具優(yōu)勢(shì)。由于MVR技術(shù)在國(guó)內(nèi)應(yīng)用的實(shí)例較少且技術(shù)尚未成熟,大多數(shù)還處于實(shí)驗(yàn)室研究階段且多集中于其性能的研究上。因此,文中對(duì)MVR系統(tǒng)進(jìn)行了簡(jiǎn)單的介紹,并以該脫硫廢水為研究對(duì)象對(duì)該系統(tǒng)性能進(jìn)行了簡(jiǎn)單的分析。通過對(duì)MVR系統(tǒng)進(jìn)行物料、能量衡算及傳熱方程的計(jì)算,建立了該系統(tǒng)的數(shù)學(xué)模型并分析了蒸發(fā)器內(nèi)蒸發(fā)壓強(qiáng)、壓縮機(jī)壓縮比、原料濃縮比等因素對(duì)MVR系統(tǒng)換熱面積、壓縮機(jī)功耗、制熱能效系數(shù)等的影響。通過對(duì)它們之間的關(guān)系曲線分析及對(duì)系統(tǒng)投資成本及操作費(fèi)用的綜合考慮,得出本系統(tǒng)的最佳操作條件為蒸發(fā)壓強(qiáng)在60~80 kPa,壓縮機(jī)壓縮比取1.6~2.2為宜。且可以在保持濃縮比不變的情況下,將濃縮液反復(fù)進(jìn)行蒸發(fā)濃縮操作以達(dá)到所需濃度。對(duì)特定工藝操作條件下MVR系統(tǒng)及三效蒸發(fā)系統(tǒng)處理該脫硫廢水進(jìn)行能耗費(fèi)用及冷卻水處理費(fèi)的比較得出,在廢水處理量為1800 kg/h的工況下MVR系統(tǒng)每年可較三效蒸發(fā)系統(tǒng)節(jié)省近66.3萬元的操作費(fèi)用。由此可知,MVR蒸發(fā)技術(shù)相對(duì)于三效蒸發(fā)系統(tǒng)而言節(jié)能效果顯著,明顯降低了企業(yè)的操作費(fèi)用,具有較好的應(yīng)用前景。最后,根據(jù)硫酸鈉的溶解度在32.4℃以下隨溫度的降低而迅速下降的特點(diǎn),本文采用冷凍結(jié)晶的方法處理MVR系統(tǒng)排放的濃縮液,使硫酸鈉以芒硝的形式析出,得到的芒硝可以達(dá)到回用要求。
[Abstract]:NaOH (or Na _ 2CO _ 3) solution is added directly to the absorber to absorb so _ 2 from waste gas. Compared with the traditional limestone / gypsum method, the sodium alkali method is more efficient than the traditional limestone / gypsum method. The desulfurization wastewater produced by this method has more than 1 inorganic salt content, which belongs to the high salt wastewater. The direct discharge of this kind of waste water will make the surrounding soil. The increase of salt content in water causes damage to the environment and waste of resources to minimize or zero discharge of high-salt wastewater in industrial production. It is of great significance to environmental protection. The main component of the wastewater is inorganic salt after the analysis of the water quality of the waste water, which is a kind of sodium-alkali flue gas desulphurization wastewater from a thermal power plant. The highest content of Na2SO4 was between 40 ~ 60 g / L, which suggested that the wastewater should be concentrated and treated by physical method. The inorganic salt and water are separated and recycled respectively. Combined with the characteristics of high salt content in desulphurization wastewater and the physical treatment technology of several kinds of high-salt wastewater, it is economical and technical. Environmental protection and other aspects of comparative analysis. The mechanical steam recompression evaporation technology (MVR) has more advantages in the concentrated treatment of the high salinity desulfurization wastewater. Because of the few examples of MVR application in China and the immature technology. Most of them are still in the stage of laboratory research and mostly focus on their performance. Therefore, this paper briefly introduces the MVR system. The performance of the desulfurization wastewater is analyzed simply, and the material, energy balance and heat transfer equation of the MVR system are calculated. The mathematical model of the system is established and the factors such as evaporator evaporation pressure compressor compression ratio and raw material concentration ratio on the heat transfer area and compressor power consumption of the MVR system are analyzed. The influence of heating energy efficiency coefficient etc. Through the analysis of the relationship curve between them and the comprehensive consideration of the system investment cost and operation cost. The optimum operating conditions of the system are as follows: evaporation pressure is 6080 KPA, compressor compression ratio is 1.6 ~ 2.2, and the concentration ratio can be kept constant. The concentrated liquid is repeatedly evaporated and concentrated to reach the required concentration. The comparison of energy consumption cost and cooling water treatment cost between the MVR system and the three-effect evaporation system for the treatment of the desulphurization wastewater under the specific process operation conditions is obtained. Under the condition that the wastewater treatment capacity is 1 800 kg/h, the MVR system can save nearly 663,000 yuan per year compared with the three effect evaporation system. Compared with the three-effect evaporation system, the MVR evaporation technology has a remarkable energy-saving effect, significantly reduces the operating costs of the enterprise, and has a good application prospect. According to the characteristic that the solubility of sodium sulfate decreases rapidly with the decrease of temperature below 32.4 鈩，

本文編號(hào)：1435507