It is with VOC industry waste gas exemple, the equipment of environmental protection of rich of grand of Zhejiang of relevant technology _ that knows industrial off-gas treatment in the round limited company

Well-known, generation of the meeting in industrial production process is many the industrial waste gas that has a harm to atmosphere environment organic gas. Current, atmosphere environment of China already was polluted badly, northward a lot of areas appeared weather of serious mist haze. Below this kind of circumstance, must increase the strength of research and development of technology of industrial off-gas treatment, be opposite through raising off-gas treatment technology to reduce its the harm of atmosphere environment. The article harm from VOC gas proceed with, understand the relevant technology of industrial off-gas treatment.

　1, VOC reachs his to endanger an overview

1.1 VOC overview

Volatile organic compound, abbreviation is VOC(VolatileOrganic Compounds)) , in industrial production, be used normally as solvent, after using, send out in atmosphere. Show level, its apply more extensive field to include petro-chemical, presswork, leatheroid and electron yuan medicine of the parts of an apparatus, Qi He that bake.

1.2 VOC endangers an overview

From the point of the property of chemical material, the domain waits in industrial production, use as commonly of solvent basically include adipose a group of things with common features acting hydrocarbon of compound, bittern is mixed compound of scent a group of things with common features. If these organic dissolvent volatilize in atmosphere environment, can cause serious pollution to atmosphere environment not only, and after the gas that human body breathes out to be polluted, produce a harm to human body health. For instance benzene, it often is regarded as a kind of dissolvent will use, volatilize as solvent in atmosphere environment, can be absorbed by the skin place of human body not only, and still can enter human body interior through respiratory system, cause chronic or virulent poisoning, the much of human body is toxic nevertheless because breathe out to be caused into toxic gas,all be.

Benzene apperception adds up to content to be able to be caused to the central nervous of human body not only damage certainly, and create neurological obstacle possibly still, blood and blood forming organ still can be endangered after entering human body, if the case is more severe, can have haemorrhage symptom even or suffer from on septicemia. Below oxidation, benzene can oxidize inside organism phenol, cause liver function thereby unusual, the growth to skeleton development is very adverse, cause aplastic anemia. If benzene vapour chroma is exorbitant, biology may die because of virulent poisoning. Accordingly, ACGIH labels benzene potential carcinogen. Apperception of bittern acting hydrocarbon adds up to content to meet those who cause neurosis Hou Qun and plaque to decrease, the bad situation such as liver splenomegaly, and cause cancer very likely. So, must control VOC discharge, this is responsible to the environment not only, also be responsible to our life health.

　　Technology of off-gas treatment of 2, VOC

Current, technology of VOC off-gas treatment basically includes heat to destroy law, pressure swing adsorption depart and purify technology, adsorptive law and combustion processing technique to wait.

2.1 heat destroy a way

Heat destroys a way is to point to mix directly auxiliary combustion organic gas, namely VOC, or the chemical response that uses appropriate activator to accelerate VOC, achieve finally reduce organic matter concentration, make its have a kind of processing technique that endangers a gender no longer.

Heat destroys the effect of organic off-gas treatment with inferior to chroma law to had been compared, accordingly, got applied extensively in handling low density waste gas. Main component is this kind of method two kinds, namely direct blaze burning and catalytic combustion. Direct blaze burning is right the heat treatment efficiency of organic waste gas is opposite taller, can achieve usually 99% . And what catalytic combustion points to is to be below the action of catalytic bed layer, accelerate the chemical response rate of organic waste gas. When this kind of method is used than direct combustion fewer, but if leave activator to assist, cannot produce effect. Show level, what can use as activator is salt of metal, metal mostly. Though the catalytic effect of these two kinds of activator has been compared, the technology also should have matured, but its price is higher however, processing cost is so higher also. In recent years, activator development is centered in direction of blame noble metal catalyst more, obtained greater progress.

In addition, in catalysis in process of organic waste gas, still need to have the carrier of activator, its are rising to heighten the main effect of catalytic active and stability. Current, regard activator as carrier with pottery and porcelain more, but among the activator research in future, should accelerate research and development efficient and active activator and its carrier.

2.2 adsorptive laws

The adsorptive law in organic waste gas basically applies to low density, tall flux organic waste gas. Show level, the processing technique of this kind of organic waste gas should have matured, energy is used up smaller, but processing efficiency is very tall however, and can purify harmful and organic waste gas thoroughly.

But this kind of method also is put in certain blemish, the equipment volume that it needs is huger, and if there are a large number of foreign matters in waste gas,technological process compares complex; , bring about a staff member easily toxic. So, the key that uses this method to handle waste gas depends on sorbent. Current, use adsorptive law to handle organic waste gas, use activated carbon more, because structure of activated carbon stoma has been compared,basically be, adsorptive sex is stronger.

In addition, through ferric oxide or ozonation, the adsorptive function of activated carbon will better, the processing of organic waste gas will more safety and effective.

2.3 biology handle a way

Tell from the fundamental of processing, use biology processing technique to handle organic waste gas, it is to use microbial physiology process the mineral with the harmful material simple translate into in organic waste gas, CO2, H2O and other are for instance simple mineral. This is a kind of hurtless means of organic off-gas treatment.

Usually, a whole live thing handles process of organic waste gas to include 3 basic measure: The organic contaminant in A) organic waste gas is contacted with water above all, can dissolve quickly in water the organic matter with deliquescent in lilquid film;b) , in liquid state chroma low circumstance falls, can diffuse stage by stage in biomembrane, be adhered to then what go up in biomembrane is microbial absorb;c) by microbial absorption organic waste gas, in process of metabolization of its oneself physiology, will by degradation, final translate into does not have harm chemical combination material to the environment.

Depart of 2.4 pressure swing adsorption and purify a technology

Depart of pressure swing adsorption and purifying a technology is to use aeriform constituent but adsorption is in the character on solid material, in organic waste gas and detached purifying device, aeriform pressure can appear to change certainly, through this kind of pressure change handles organic waste gas.

What PSA technology basically applies is physical law, through physics Falaishi shows those who have machine waste gas to purify, use material basically is zeolite element sieve. Zeolite element is sifted, measure two respects to have definite advantage with adsorption optionally in adsorption. Below constant temperature and pressure, element of this kind of zeolite sifts the organic composition in OK and adsorptive organic waste gas, transport odd gas in issueing a segment next. After adsorptive and organic waste gas, change its through due process, maintain and improve the recovery capability of sorbent, can let sorbent be thrown again then use, repeat next on measure working procedure, relapse circularly, get depurative till organic waste gas.

In recent years, this technology begins to produce medium applying in industry, to gas depart has favorable effect. The main advantage of this technology has: Taller, environment pollutes purity of the mixture after the sources of energy uses up little, cost to operate automation and depart to purify than inferior, working procedure small etc. The aeriform result that uses this technology to have fair value with processing to reclaiming is favorable.

2.5 oxidation law

To poisonous, harmful, and the VOC that does not need to reclaim, hot oxidation law is the processing technology that suits most and method. The fundamental of oxidation law: VOC and O2 produce oxidation reaction, generate CO2 and H2O, chemical equation is as follows:

ACxHyOz+bO2 → CCO2+dH2O

Look from chemical reaction equation, the combustion process photograph on this oxidation reaction and chemistry is similar, but its because VOC density is lower, macroscopical blaze won’t arise in chemical reaction. Usually, oxidation law passes the success that two kinds of methods can ensure oxidation reacts: A) heats. Make the organic waste gas that contains VOC achieves reaction temperature;b) to use activator. If temperature is lower, oxidize reaction can undertake in activator surface. So, the oxidation law cent of organic off-gas treatment is the following two kinds of methods:

Law of A) catalysis oxidation. Show level, the activator that catalytic oxidation law uses has two kinds, namely noble metal catalyst and blame noble metal catalyst. Noble metal catalyst basically includes Pt, Pd to wait, they depend on with fine grained form go up in activator carrier, and activator carrier is metal or beehive of pottery and porcelain normally, or noble metal catalyst of blame of bulk filling; basically is by transfer elemental metal oxide, for instance MnO2, mix through certain proportion with adhesive, the activator that makes next. To prevent effectively catalytic active is lost after activator is toxic, must keep clear of thoroughly before processing but the substance with activation toxic agent, for instance Pb, Zn is mixed Hg. If the activator poison in organic waste gas, cover cannot keep clear of character, cannot use law of oxidation of this kind of catalysis to handle VOC;

B) heats up oxidation law. Current cent is hot oxidation law 3 kinds: Type of type of heating power combustion, next door type, accumulation of heat. The main distinction of 3 kinds of methods is returning debit form at quantity of heat. These 3 kinds of methods all can catalytic law is united in wedlock, drop the reaction temperature of chemical reaction.