濕法沼氣脫硫是指應(yīng)用液體吸收劑(如水或堿性溶液等)洗滌煙氣脫除煙氣中的SO2。它的優(yōu)點是脫硫效率高,設(shè)備小、投資省、操作較容易、容易控制以及占地面積小;而缺點是易造成二次污染,存在廢水后處理問題,能耗高,特別是洗滌后煙氣的溫度低,不利于煙囪排氣的擴散,易產(chǎn)生“白煙”,需要二次加熱,腐蝕嚴重等。主要的方法有
Wet biogas desulfurization refers to the application of liquid absorbents (such as water or alkaline solutions) to wash flue gas and remove SO2 from flue gas. Its advantages are high desulfurization efficiency, small equipment, low investment, easy operation, easy control, and small footprint; The disadvantage is that it is easy to cause secondary pollution, there is a problem of wastewater post-treatment, high energy consumption, especially the low temperature of the flue gas after washing, which is not conducive to the diffusion of chimney exhaust, easy to generate "white smoke", requires secondary heating, and severe corrosion. The main methods are
石灰石-石膏法該工藝是利用石灰石/石灰石漿液洗滌煙道氣,使之與SO2反應(yīng),生成亞硫酸鈣(CaSO3),經(jīng)分離的亞硫酸鈣可以拋棄,也可以通入空氣強制氧化和加入一些添加劑,以石膏形式進行回收。為了減輕SO2洗滌設(shè)備的負荷,先要將煙道氣除塵,然后再進入除塵設(shè)備與吸收液發(fā)生反應(yīng)。石灰/石灰石-石膏法技術(shù)比較成熟,吸收劑價廉易得,運行可靠,應(yīng)用廣,脫硫效率可達90%以上。
The limestone gypsum method is a process that uses limestone/limestone slurry to wash the flue gas and react with SO2 to generate calcium sulfite (CaSO3). The separated calcium sulfite can be discarded, or air can be introduced for forced oxidation and some additives can be added to recover it in the form of gypsum. In order to reduce the load of SO2 washing equipment, the flue gas needs to be removed from the dust first, and then it enters the dust removal equipment to react with the absorption liquid. The lime/limestone gypsum method technology is relatively mature, with inexpensive and easily available absorbers, reliable operation, and the widest application, with a desulfurization efficiency of over 90%.
鈉法此法是用氫氧化鈉、碳酸鈉、或亞硫酸鈉溶液為吸收劑吸收煙氣中的SO2,因該法具有對SO2吸收速度快,管路和設(shè)備不易堵塞等優(yōu)點,所以應(yīng)用比較廣泛,吸收液可以經(jīng)無害化處理后棄去或適當方法處理后獲得副產(chǎn)品NaSO3晶體、石膏、硫酸等。 鎂法此法具有代表性的工藝有西德WilhlmGrillo公司發(fā)明的基里洛法和美國ChemicalConstructionCo發(fā)明的凱米克法。
Sodium method: This method uses sodium hydroxide, sodium carbonate, or sodium sulfite solution as absorbent to absorb SO2 in flue gas. Due to its advantages of fast SO2 absorption speed, less clogging of pipelines and equipment, it is widely used. The absorption solution can be discarded after harmless treatment or processed by appropriate methods to obtain by-products such as NaSO3 crystals, gypsum, sulfuric acid, etc. The representative processes of magnesium method include the Kirilo method invented by Wilhlm Grillo Company in West Germany and the Kemmick method invented by Chemical Construction Co. in the United States. Kirilot method
是用吸收性能好并容易再生的MgxMnOy為吸收劑吸收煙氣中的SO2,此法所得副產(chǎn)物H2SO4的濃度可達98%。凱米克法又稱氧化鎂法,用串聯(lián)兩個文丘里除塵器除去煙氣中微小的塵粒,并用MgO溶液吸收煙氣中的SO2。吸收過程中生成的MgSO4·7H2O和MgSO4·6H2O的晶體與焦碳一起在1000℃下加熱分解得到SO2和MgO。再生的MgO可重新用作吸收劑。
MgxMnOy with good absorption performance and easy regeneration is used as an absorbent to absorb SO2 in flue gas. The concentration of by-product H2SO4 obtained by this method can reach 98%. The Kemmick method, also known as the magnesium oxide method, uses two Venturi dust collectors in series to remove small dust particles from the flue gas, and uses a MgO solution to absorb SO2 from the flue gas. The crystals of MgSO4.7H2O and MgSO4.6H2O generated during the absorption process are heated and decomposed with coke at 1000 ℃ to obtain SO2 and MgO. The regenerated MgO can be reused as an absorbent.
氨法此法是用氨水為吸收劑吸收煙氣中的SO2,其中間產(chǎn)物為亞硫酸銨和亞硫酸氫銨,采用不同方法處理中間產(chǎn)物可回收硫酸銨、石膏、單體硫等副產(chǎn)品。
Ammonia method This method uses ammonia water as an absorbent to absorb SO2 in flue gas, and the intermediate products are ammonium sulfite and ammonium bisulfite. Different methods are used to treat the intermediate products, which can recover by-products such as ammonium sulfate, gypsum, and monomer sulfur.
磷銨復(fù)肥法該法是利用天然磷礦石和氨為原料,在煙氣脫硫過程中副產(chǎn)品為磷銨復(fù)合肥料,工藝流程主要包括四個過程,即:活性炭一級脫硫并制得稀硫酸;稀硫酸萃取磷礦制得稀硫酸溶液;磷酸和氨的中和液[(NH4)2HPO4]二級脫硫;料漿濃縮干燥制磷銨復(fù)肥。脫硫效率為95%以上。
The ammonium phosphate compound fertilizer method uses natural phosphorus ore and ammonia as raw materials, and the by-product in the flue gas desulfurization process is ammonium phosphate compound fertilizer. The process mainly includes four processes, namely: primary desulfurization with activated carbon and preparation of dilute sulfuric acid; Extracting phosphate rock with dilute sulfuric acid to obtain a dilute sulfuric acid solution; Neutralizing solution of phosphoric acid and ammonia [(NH4) 2HPO4] for secondary desulfurization; Concentrate and dry the slurry to produce ammonium phosphate compound fertilizer. The desulfurization efficiency is above 95%.