工業(yè)廢氣是大氣污染物的重要來源，工業(yè)廢氣的高效治理顯得非常重要，今天為大家介紹常見的六類工業(yè)廢氣的治理技術(shù)，再也不用為廢氣治理發(fā)愁了。
一、碳?xì)浠衔锏膬艋?br>燃燒法
用燃燒方法銷毀有害氣體、蒸氣或煙塵，使其變?yōu)闊o害物質(zhì)的過程，稱為燃燒凈化。燃燒凈化時(shí)所發(fā)生的化學(xué)作用主要是燃燒氧化作用及高溫下的熱分解。
目前在實(shí)際中使用的燃燒凈化方法有直接燃燒和熱力燃燒。對(duì)化工、噴漆、絕緣材料等行業(yè)的生產(chǎn)裝置中所排出的有機(jī)廢氣，廣泛采用了燃燒凈化的手段。
特點(diǎn)：用于凈化那些可燃的或在髙溫情況下可以分解的有害氣體，還可以用來消除惡臭，回收熱量。
催化燃燒法
即在催化劑作用下，使廢氣中的有害可燃組分氧化為co2和h2o。由于絕大部分有機(jī)物均具有可燃燒性，因此催化燃燒法已成為凈化含碳氧化合物廢氣的有效手段之一。
目前催化燃燒法已應(yīng)用于金屬印刷、絕緣材料、漆包線、煉焦、油漆、化工等多種行業(yè)中凈化有機(jī)廢氣。
特點(diǎn)：因廢氣溫度較高、有機(jī)物濃度較髙，對(duì)燃燒反應(yīng)及熱量回收有利，具有較好的經(jīng)濟(jì)效益，因此應(yīng)用廣泛。
吸附法
作為凈化碳?xì)浠衔飶U氣的吸附劑有活性炭、硅膠、分子篩等，利用吸附劑對(duì)有機(jī)物進(jìn)行吸附，其中應(yīng)用泛、的吸附劑是活性炭。
特點(diǎn)：
①可以相當(dāng)?shù)貎艋瘡U氣，即可進(jìn)行深度凈化，特別是對(duì)于低濃度廢氣的凈化比用其他方法顯現(xiàn)出吏大的優(yōu)勢(shì)；
②在不使用深冷、髙壓等手段下，可以有效地回收有價(jià)值的有機(jī)物組分。
吸收法
在對(duì)碳?xì)浠衔飶U氣進(jìn)行治理的方法中，吸收法的應(yīng)用不如燃燒法、催化燃燒法、吸附等廣泛，特別是對(duì)使用有機(jī)溶劑的各種行業(yè)，如噴漆、絕緣材料、漆包線等的生產(chǎn)過程所排出的廢氣，還不能達(dá)到工業(yè)應(yīng)用水平。
影響應(yīng)用的主要問題是合適的吸收劑的選擇。
目前在石油煉制及石油化的生產(chǎn)及儲(chǔ)運(yùn)中采用吸收法進(jìn)行烴類氣體的回收利用。
冷凝法
利用物質(zhì)在不同溫度下具有不同飽和蒸汽壓這一物理性質(zhì)，采用降低系統(tǒng)溫度或提高系統(tǒng)壓力的方法，使處于蒸汽狀態(tài)的污染物冷凝并從廢氣中分離出來的過程。
特點(diǎn)：
冷凝凈化法適用范圍冷凝凈化法適于在下列情況下使用。
處理高濃度廢氣，特別是含有害物組分單純的廢氣；
作為燃燒與吸附凈化的預(yù)處理；特別是有害物含量較高時(shí)，可通過冷凝回收的方法減輕后續(xù)凈化裝置的操作負(fù)擔(dān)；
處理含有大量水蒸氣的高溫廢氣。
冷凝凈化法所需設(shè)備和操作條件比較簡(jiǎn)單回收物質(zhì)純度髙。
冷凝凈化法對(duì)廢氣的凈化程度受冷凝溫度的限制，要求凈化程度髙或處理低濃度廢氣時(shí)，需要將廢氣冷卻到很低的溫度，經(jīng)濟(jì)上不合算。
二、含硫廢氣的凈制
該法是使用粉狀、粒狀吸收劑，吸附劑或催化劑去除廢氣中的80%。
優(yōu)點(diǎn)：治理中無廢水、廢酸排出，減少了二次污染。
缺點(diǎn)：脫硫效率較低，設(shè)備廢大，操作要求髙。
濕法脫硫
該法是采用液體吸收劑如水或械溶液洗涂含s02的煙氣，通過吸收去除其中的s02。由于使用不同的吸收劑可獲得不同的副產(chǎn)物而加以利用，因此濕法脫硫是各國(guó)研究最多的方法。
優(yōu)點(diǎn)：濕法脫硫所用設(shè)備較簡(jiǎn)單，操作容易，脫硫效率較高。
缺點(diǎn)：脫硫后煙氣溫度較低，于煙囪排煙擴(kuò)散不利。
三、含h2s廢氣的凈制
干法脫硫
干法是利用的還原性和可燃性，以固體氧化劑或吸附劑來脫硫，或者直接使之燃燒。干法脫硫是以氧氣使h2s氧化成硫或硫氧化物的一種方法，也可稱為干式氧化法。
常用的有改進(jìn)的克勞斯法、氧化鐵法、活性碳吸附法、氧化鋅法和卡太蘇耳法。
所用的脫硫劑、催化劑有活性炭、氧化鐵、氧化鋅、二氧化錳及鋁礬土，此外還有分子篩、離子交換樹脂等。一般可回收硫、二氧化硫、硫酸和硫酸鹽。
吸收劑有甲醇、碳酸丙烯酯、聚乙二醇二甲醚等，不僅能脫除硫化氫，氧硫化碳、二硫化碳等，溶液可以再生，并將硫化氫回收，而且也能選擇性地吸收二氧化碳。
化學(xué)吸收法
常用的有氨水催化法及改良蒽醌二磺酸法（砷堿法因溶液有毒已較少采用）。
四、nox廢氣的凈制
煙氣脫硝
在煙氣凈化技術(shù)上控制nox排放，目前主要方法有選擇性非催化還原sncr、選擇性催化還原scr、低氮燃燒技術(shù)和電子束照射法、臭氧氧化法、吸附法、氧化吸收法等。其中，選擇性非催化還原sncr、選擇性催化還原scr，低氮燃燒，臭氧氧化法等技術(shù)已商業(yè)化。
五、含鹵素廢氣的凈制
1、含氟廢氣的凈制
該法是以粉狀的吸附劑吸附廢氣中的氟化物。該凈化方法首先是煙氣與吸附劑的接觸，完成吸附過程;二是煙氣與吸附劑分開。該過程都是在吸附設(shè)備中完成的。
特點(diǎn)：凈化效率高、工藝簡(jiǎn)單、沒有水的二次污染，也不受各種氣候的影響，但凈化設(shè)備的體積較大。
吸收法
該法是用水、減性溶液或某些鹽類溶液來吸收含氟廢氣中的氟化物，從而達(dá)到凈化回收的目的，同時(shí)還可以得到副產(chǎn)品氟硅酸、冰晶石、氟硅酸鈉及氟硅脲等。
水法吸收和堿吸收法是常用的兩種方法。
特點(diǎn)：凈化工藝過程可以連續(xù)操作和回收各種氟化物，凈化效率高、效果好；其缺點(diǎn)是會(huì)造成二次污染，在寒冷地區(qū)還需保溫措施。
稀釋法
是向含氟氣體的廠房送新鮮空氣或?qū)⒑鷱U氣向高空排放進(jìn)行自然稀釋。這種方法一般不采用。
2、含氯廢氣的凈制
含氯廢氣的治理主要是通過濕法來凈化，一般是采用化學(xué)中和法、氧化還原法等過程對(duì)廢氣進(jìn)行吸收，作到綜合利用。
堿液中和法
即以堿液作為吸收液對(duì)氯氣進(jìn)行吸收，常用的吸收劑有氫氧化鈉溶液、碳酸鈣溶液、石灰乳溶液等。
或氯化亞鐵吸收法
該方法以氯化亞鐵或作為吸收劑，據(jù)氧化還原反應(yīng)性質(zhì)對(duì)氯氣進(jìn)行回收與凈化。其工藝設(shè)備可采用填料塔，并以廢鐵屑作填料，生產(chǎn)的三氯化鐵可作為防水劑，三價(jià)鐵可被鐵屑還原，再次參與吸收反應(yīng)。
特點(diǎn)：該方法設(shè)備簡(jiǎn)單，操作容易，廢鐵屑來源豐富，技術(shù)合理；但反應(yīng)速度比中和法要慢，效率較低。
吸收法
當(dāng)氯氣濃度大于1%時(shí)，可采用為吸收劑，其設(shè)備可采用噴淋或填充塔，在吸收塔內(nèi)將氯的吸收液通過加熱或吹脫解吸回收的氯氣可再次使用。
水吸收法
當(dāng)氯氣濃度＜1%時(shí)，有時(shí)可用水通過噴淋塔來吸收氯氣，其效果不如堿性中和法好。用水蒸氣加熱解吸時(shí)可回收氯氣，如國(guó)內(nèi)的一些氯堿廠在“氯水”解吸時(shí)用蒸氣或熱交換方法回收氯氣。
此外，還有用硅膠、活性炭、離子交換樹脂等進(jìn)行吸附的方法，但因成本太高或是技術(shù)還不十分成熟而沒有得到廣泛的應(yīng)用。
六、廢氣的凈制
水吸收法
處理主要采用水吸收法。水吸收法是基于氣體易溶于水的原理常常采用水直接吸收氣體。當(dāng)所得溶液達(dá)到一定濃度時(shí)，經(jīng)凈化濃縮可得到副產(chǎn)品鹽酸。
同時(shí)，處理廢氣還有堿液吸收法，聯(lián)合吸收法以及冷凝法。
industrial emissions is an important source of atmospheric pollutants, efficient treatment of industrial waste gas is very important today to introduce common governance six industrial gas technology, no longer have to worry about gas treatment.
a hydrocarbon purification
combustion
combustion method to destroy harmful gases, vapors or dust, it becomes harmless substances in the process, called combustion purification. chemical reaction that occurs when combustion purification mainly thermal combustion oxidation and high temperature decomposition.
currently combustion purification methods used in practice have a direct combustion and heat of combustion. chemical, paint, insulation materials and other industries in the production unit of organic waste discharged, a widely used means of combustion purification.
features: for purifying harmful gas or in the case of gao temperature can break those flammable, can also be used to eliminate odor, heat recovery.
catalytic combustion
that is in the catalyst, the exhaust gas harmful combustible components are completely oxidized to co2 and h2o. since most organic compounds have can burn, therefore the catalytic combustion has become one of the effective means to purify exhaust gases containing carbon and oxygen compounds.
currently catalytic combustion method has been applied to the metal printing, insulation materials, wire, coke, paint, chemical and other industries in the organic waste gas purification.
features: due to the higher exhaust gas temperature, concentration of organic matter than the gao, the combustion reaction and heat recovery favorable, with good economic and therefore the most widely used.
adsorption
as the exhaust gas purifying hydrocarbon adsorbent activated carbon, silica gel, molecular sieve, using an adsorbent for adsorption of organic matter, including the most widely used, the best effect is activated carbon adsorbent.
features:
① can be quite thoroughly purify exhaust gas, deep purification can be carried out, especially for the low-concentration exhaust gas purification using other methods show officials large odds ratio;
② without the use of deep cold, under pressure of gao and other means to effectively recover valuable organic components.
absorption
on hydrocarbons in the exhaust gas treatment method, absorption method of application is better combustion, catalytic combustion, adsorption and so widely, particularly on the use of organic solvents in a variety of industries, such as painting, insulation materials, wire and other production processes the exhaust gas, it can not fully meet the level of industrial application.
the main issues affecting the application of suitable absorbent choice.
currently recycling hydrocarbon gas absorption method using the oil refining and petrochemical production and storage and transportation.
condensation method
the use of material having different saturation vapor pressure at different temperatures, the physical properties, the use of lower system temperature or pressure of the system to improve the ways in which the condensed contaminants in the vapor state and separated from the exhaust gas process.
features:
condensate purification method scope condensate purification method is suitable for use in the following cases.
treatment of high concentration waste gas, particularly those containing harmful components of exhaust gas alone;
as a pretreatment of the combustion and adsorption clarifier; especially when high content of harmful substances, can reduce the operational burden of the subsequent purification by means of condensation recovery method;
processing of high temperature exhaust gas containing a large amount of water vapor.
condensate purification method required equipment and operating conditions are relatively simple purity of recovered material gao.
condensate purification method for purifying exhaust gas is limited by the degree of condensation temperature required degree of purification or treatment gao low concentration waste gas, the waste gas needs to be cooled to very low temperatures, economically viable.
second, the net sulfur exhaust system
this method is the use of powdered, granular absorbents, adsorbents or catalyst removal in the exhaust gas of 80%.
advantages: no waste water treatment, waste acid discharge, reduce the secondary pollution.
disadvantages: desulfurization efficiency is low, large waste facilities, operating requirements gao.
wet desulfurization
the method is the use of a liquid absorbent, such as water or mechanical wash coat solution containing s02 flue gas by absorption to remove one of the s02. due to the use of different absorbent obtain different by-products and take advantage of, so wet desulphurization was the most national research method.
advantages: wet desulfurization equipment used is relatively simple, easy to operate, high desulfurization efficiency.
disadvantages: low temperature flue gas desulfurization, chimney smoke diffusion in the negative.
third, the exhaust gases containing h2s net system
dry desulfurization
dry method is the use of combustible and reducing to an oxidizing agent or a solid adsorbent desulfurization, or simply to make it burn. dry desulfurization make h2s is oxidized to sulfur oxygen or sulfur oxides a method, also known as dry oxidation method.
commonly used to improve the claus process, iron oxide method, activated carbon adsorption, zinc oxide and chi too su ear method.
the desulfurization agent used, catalysts are activated carbon, iron oxide, zinc oxide, manganese dioxide and bauxite, in addition to molecular sieves, ion exchange resins and the like. usually recoverable sulfur, sulfur dioxide, sulfuric acid and sulfates.
absorbents, methanol, propylene carbonate, polyethylene glycol dimethyl ether, etc., not only to remove hydrogen sulfide, carbonyl sulfide, carbon disulfide, the solution can be regenerated and recycled hydrogen sulfide, but also capable of selectively removing carbon dioxide .
chemical absorption
commonly used ammonia catalytic anthraquinone disulfonic acid and improvement act (arsenic soda solution because toxic has been less used).
fourth, the net made nox exhaust gas
flue gas denitrification
in the flue gas purification technology to control nox emissions, the main method of selective non-catalytic reduction sncr, selective catalytic reduction scr, low nox combustion technology and electron beam irradiation, ozone oxidation, adsorption, absorption oxidation method. wherein the selective non-catalytic reduction sncr, selective catalytic reduction scr, low nox combustion, ozone oxidation technology has been commercialized.
fifth, the halogen-containing exhaust gases net system
1, net made of fluorine gas
the method is based on powdered adsorbent exhaust gas fluoride. the flue gas purification method first contact with the adsorbent, the adsorption process is completed; the second is separated from the flue gas with the adsorbent. this process is done in the adsorption device.
features: high purification efficiency, simple process, no secondary pollution of water, is not affected by all kinds of weather, but the larger the volume of purification equipment.
absorption
the law is water, some subtractive solution or salt solution to absorb fluoride fluorine-containing exhaust gas, so as to achieve the purpose of purification and recovery, but also can be a by-product fluosilicic acid, cryolite, sodium fluoride and silicon fluoride urea or the like.
water absorption and alkali absorption method is commonly used in two ways.
features: purification process can be operated continuously and recycling of fluorides, high purification efficiency, good effect; the drawback is cause secondary pollution, insulation measures needed in cold areas.
dilution
fresh air is sent to a gas containing fluorine or fluorine-containing gas plant to high-altitude emissions for natural dilution. this method is generally not used.
2, net made of chlorine gas
chlorine gas governance mainly through wet to purify, is generally used in the chemical process and method, redox method of gas absorption, utilization done.
lye and law
namely lye as the absorbing liquid to absorb chlorine, sodium hydroxide solution commonly used absorbent, sodium carbonate solution, lime solution and the like.
ferrous sulfate or ferrous chloride absorption method
in this method, ferrous chloride or ferrous sulfate as an absorbent, according to the nature of the redox reaction of chlorine gas is recovered and purified. its process equipment can be packed towers, and scrap iron as a filler, the production of ferric chloride can be used as a waterproofing agent, ferric iron can be reduced again to participate in the absorption reactions.
features: this method is simple equipment, easy to operate, a rich source of scrap iron, technically sound; but the reaction rate is slower than the neutralization method, less efficient.
ctc absorption spectrometry
when the chlorine concentration is greater than 1%, it can be used as absorbent carbon tetrachloride, which can be spray equipment or packed column, in the absorber absorbing liquid chlorine by heating or stripping desorption recycling of chlorine can be used again.
water absorption spectrometry
when the chlorine concentration of <1%, sometimes by spraying water tower to absorb chlorine, are less effective than alkaline and good law. recyclable chlorine by heating the desorption of water vapor, such as some domestic chlor-alkali plants in the chlorine desorption-recovery steam or heat exchange process chlorine.
in addition, there were adsorption method using silica gel, activated carbon, ion exchange resin, but the cost is too high or the technology is not very mature and has not been widely used.
sixth, the net hydrogen chloride gas
water absorption spectrometry
mainly deal with hydrogen chloride water absorption. water absorption principle is soluble in water-based gas is often used water directly absorb hydrogen chloride gas. when the resulting hydrogen chloride solution reaches a certain concentration, purified and concentrated hydrochloric acid by-product can be obtained.
at the same time, the process of hydrogen chloride gas as well as alkali absorption method, combined with absorption and condensation.
關(guān)鍵詞：絕緣材料 催化劑 吸附劑 活性炭 濕法脫硫