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火電廠煤炭脫硫工藝綜述畢業(yè)論文(參考版)

2025-07-01 01:20本頁面
  

【正文】 參考文獻[1][J].潔凈煤技術,1998(4).[2]蔡章,[J].煤炭加工與綜合利用,1995(2).[3][M].北京:煤炭工業(yè)出版社,1997.[4][M].國家環(huán)境保護總局,1998.[5]樂勝,[J].山東電力技術,2000(5).。化學方法和生物方法脫硫可以實現(xiàn)煤的深度脫硫,有待繼續(xù)深入研究和發(fā)展。目前就我國實際狀況而言,短期內(nèi)燃前脫硫會以物理脫硫為主, mm的細粒煤脫硫降灰仍是煤炭脫硫的難點,以重選和浮選為主的煤炭洗選過程,是煤炭燃前脫硫最具規(guī)模且最經(jīng)濟的方法。無機硫含量愈高,浮選微生物脫硫效率就愈高另外,通過經(jīng)濟分析,該技術的經(jīng)濟可行性十分顯著,運行成本很低,脫除1 ,隨著技術的發(fā)展,還可進一步降低運行費用。在浮選柱中氣泡的推動下,煤炭顆粒上浮而黃鐵礦顆粒則下沉至底部,從而把煤和黃鐵礦分開。由于空氣和水的浮力作用,兩者一起浮于水面不能分開。(2)表面處理法。由于是將煤中的硫直接代謝轉(zhuǎn)化,當采用合適的微生物時,還能同時處理煤中的無機硫和有機硫,理論上具有很大的應用價值。生成的硫酸在煤堆的底部收集,從而達到從煤中去除硫的目的。生物浸出法就是利用微生物的氧化作用將黃鐵礦氧化分解成鐵離子和硫酸,硫酸溶于水后將其從煤炭中排除的脫硫方法。它是通過培育出針對含硫化合物的菌種,利用煤中含硫化合物的生物化學反應,使含硫化合物氧化后,用酸洗、瀝濾的方法實現(xiàn)脫硫。其原理是利用一種低分子量化合物(通常用液氨或濃氨水)迅速滲透到煤中天然裂縫中,并破壞了煤中的結合鍵,從而使煤沿著層理面以及礦物質(zhì)與煤有機質(zhì)的結合面出現(xiàn)選擇性破碎。(5)化學破碎。該類方法是利用加氫反應,在高溫高壓下將煤中的硫轉(zhuǎn)化為硫化氫,以生產(chǎn)潔凈半焦為目的。熔融堿法是用熔融堿進行脫硫,熔融堿能與煤中的礦物質(zhì)、有機硫反應生成可溶性物質(zhì),從而得到凈化煤,甚至可以得到超凈化煤;有機溶劑抽提法中目前比較成熟的是全氯乙烯脫硫工藝,它是利用全氯乙烯萃取煤中的有機硫,而硫鐵礦和其他礦物質(zhì)則利用重力浮沉除去,%[5];超臨界流體萃取法用于脫硫是近年出現(xiàn)的新方法,目前還沒有工業(yè)化。(3)溶劑法脫硫。主要有兩種方法:KVB法和氯解法。主要有3種方法:熱堿液浸出法,又稱水熱法,它是用Na2CO3 4%~10%和Ca(OH)2 2%的混合水溶液為浸出劑,可將煤中硫鐵礦轉(zhuǎn)化為可溶性硫化物、硫代硫酸鹽、有機硫轉(zhuǎn)化為硫化氫,從而達到脫硫的目的;Meyers法,該法是利用Fe2(SO4)3中3價鐵的氧化性將硫鐵礦轉(zhuǎn)化為可溶性的FeSO4,對有機硫不起作用;氧化法脫硫,該類方法是利用空氣在較高的溫度和壓力下氧化煤中的硫鐵礦和有機硫生成可溶性的硫酸鹽或硫酸。常見化學脫硫方法及脫硫效果見文獻[3]。物理脫硫法不能脫除煤中的有機硫,化學脫硫法則可脫除部分有機硫(25%~70%)。美國在微泡浮選柱和油團選方面已投入工業(yè)應用。電選法是利用煤顆粒與雜質(zhì)顆粒導電性的差別進行分選的。煤中主要的含硫物質(zhì)——黃鐵礦,雖然是順磁性的,但磁性很小,很難直接用磁選法分離。(3)按磁性差異脫硫。據(jù)煤中的礦物雜質(zhì)顆粒與精煤顆粒的表面性質(zhì)不同,常用“浮選法”進行脫硫。這是目前煤炭燃前脫硫的主要方法,它是根據(jù)煤巖與含硫無機化合物的密度不同而將其分離的方法,比較常用的是“重力法”。物理脫硫技術常見的物理脫硫方法及效果見文獻[2]。物理脫硫法是依據(jù)煤炭顆粒與含硫化合物的密度、磁性、導電性及其懸浮性差異而除去煤中無機硫的方法,目前已有成熟工藝和設備。1燃前脫硫的方法及效果煤的燃前脫硫主要是在選煤廠進行。根據(jù)控制SO2排放的工藝在煤炭燃燒過程中的位置,可將脫硫技術分為燃燒前、燃燒中和燃燒后3種。為了減少SO2的污染,世界各國都制定了相應的環(huán)保法規(guī)。 supercritical fluid extraction is used for desulfurization of the new method in recent years, there has not been industrialized. (4) hightemperature pyrolysis gas desulfurization. Such method is the use of hydrogenation, high temperature and high pressure in the sulfur coal into hydrogen to produce cleaner for the purpose of semicoke. The Act can be substantial increase in tar, crude benzene recovery rate, easy to use chemicals. (5) Chemical broken. The law is the United States Syracuse University as a research and development of coal dry separation method, referred to as Act SURC. The principle is that using a lowmolecularweight pounds (usually ammonia or concentrated ammonia) rapidly penetrated into natural fractures in coal, and destruction of the coal in a bination of keys so that coal, as well as along the bedding surface of minerals and coal The bination of surface organic matter appears broken selectively. biodesulfurization coal Microbial desulfurization of coal is also targeted desulfurization method. It is through the sulfur pounds produced for the bacteria, the use of coal in the biochemical reactions of sulfur pounds, so that after the oxidation of sulfur pounds, using acid leaching methods to achieve desulfurization. At present, the microbial desulfurization of coal mainly in the following two methods: (1) bioleaching. Bioleaching is the use of microorganisms for the oxidation With the oxidation of pyrite into iron ions and sulfuric acid, sulfuric acid soluble in water will be excluded from the coal desulphurization methods. The advantage of this approach is a simple device, just above the Coal sprinkled water containing microorganisms through the water to soak in the realization of microorganisms in the coal desulfurization. Coalgenerated sulfuric acid in the bottom of the collection, so as to achieve removal of sulfur from coal purposes. This method is technically more mature, they are satisfied with the efficiency of desulfurization. Because coal is a direct metabolic conversion of sulfur, when used at the appropriate microorganisms, but also at the same time dealing with the inorganic sulfur in coal and organic sulfur, in theory, has great application value. However, its fatal drawback is a longer processing time, using this method to deal with a group of coal, it normally takes more than 30 days, and the leaching of the waste in time if they can not handle, it is easy to cause secondary pollution.(2) This approach to toppling coal particles and mixed with water in the suspension the following microbubble blowing, coal and pyrite were attached to the bubble surface. Air and water as a result of the buoyancy effect, the two together can not be floating on the water surface. If the microorganisms in aqueous solution is added, as a result of microorganisms attached to the surface of pyrite particles, making the surface of pyrite from hydrophobic into hydrophilic, at the same time, it remains difficult for microorganisms attached to the surface of coal particles and still maintain their hydrophobic surface characteristics. Bubble in the flotation column, driven by coal and pyrite particles floating particles are sinking to the bottom, so as to separate the coal and pyrite. This method can greatly reduce the processing time. Inorganic
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