What Causes Air Pollution?

Air pollution, also known as air pollution. According to the definition of the International Organization for Standardization (ISO), air pollution usually refers to the fact that certain substances enter the atmosphere due to human activities or natural processes, presenting sufficient concentrations to reach sufficient time. And therefore endanger human comfort, health and welfare or environmental phenomena.

The atmosphere is composed of a certain proportion

source

The source of air pollution is the source of air pollutants, which mainly include the following:

(1) Industry: Industrial production is an important source of air pollution. Pollution from industrial production into the atmosphere

The hazards of air pollution are mainly the following aspects

Harm the human body

The harmful effects of air pollutants on the human body are multi-faceted. The main manifestations are respiratory diseases and physiological dysfunctions, and the irritation of mucous membrane tissues such as eyes and nose. It is a chronic factor that causes elderly asthma. Lung deficiency causes physical decline.

When the concentration of pollutants in the atmosphere is very high, it can cause acute pollution poisoning, or worsen the condition, and even kill thousands of people within a few days. In fact, even if the concentration of pollutants in the atmosphere is not high, the human body breathing this polluted air over the years will cause

A large amount of charcoal heating caused the death of Kangxi Qianlong

The impact of air pollution sources can be seen from two aspects: source intensity and source height. Source intensity is the rate at which pollutants are emitted. Concentration of pollutants and

Air pollution prevention

Preventing air pollution is a huge systematic project that requires the joint efforts of individuals, collectives, nations, and even countries around the world. The following measures can be considered.

Reduce pollution emissions

Reform the energy structure and use more pollution-free energy (such as solar, wind, and hydropower)

Solar energy

And low-pollution energy sources (such as natural gas), pretreatment of fuels (such as desulfurization before burning coal), and improved combustion technologies can reduce emissions. In addition, before the pollutants enter the atmosphere, the use of dust removal and smoke removal technology, condensation technology, liquid absorption technology, and recycling technology to eliminate some pollutants in the exhaust gas can reduce the amount of pollutants entering the atmosphere. Plant purification method, China has been using plant-based disinfection for more than 3,000 years.

Self-cleaning ability

Different meteorological conditions, the atmosphere's capacity for pollutants is different, the same amount of pollutants are discharged, resulting in different concentrations of pollutants. For areas and periods with strong wind, good ventilation, strong turbulence, and strong convection, the atmospheric diffusion and dilution ability is strong, and it can accept more activities of factories and mines. In areas and periods where temperature is inverse, the ability of the atmosphere to diffuse and dilute is weak, so it cannot accept more pollutants, otherwise it will cause serious atmospheric pollution. Therefore, effective control of emissions in different regions and at different times should be implemented.

industrial area

Site selection, chimney design, urban and industrial zone planning, etc. must be reasonable. Do not over-concentrate emissions, do not cause repeated pollution, and serious local pollution incidents will occur.

Afforestation

The dense forest can reduce the wind speed and reduce the large particles of dust carried in the air. The surface of the leaves is rough and uneven, some have fluff, and some can secrete mucus and oil, so they can absorb a large amount of dust. Dust-covered leaves can continue to absorb flying dust after being washed by rain. This reciprocating obstruction and adsorption of dust can make the air purified.

Change fuel composition

Carry out the conversion from coal to gas. At the same time, step up research and development of other new energy sources, such as solar energy, hydrogen fuel, and geothermal. This can also greatly reduce the pollution of soot.

starting from myself

Do not litter; travel by bus or subway to reduce the use of private cars; participate in greening activities such as planting trees; install exhaust treatment devices on private cars; use lubricating oil to fully burn fuel and reduce harmful gas emissions.

Reduce haze weather going out (According to related explanations, Ozone is ozone, and PM2.5 refers to fine suspended particles with a diameter of less than 2.5 microns, also known as inhalable particulate matter. Killer. "Causes extensive damage to the respiratory system, heart and blood system, etc.).

Wear masks when going out (Materials, service life, technical level and other factors are the standards that define the quality of masks. Consumers do not have to buy "conceptual masks" with various effects unless they have special needs).

Properly cultivate some green plants such as spider plants indoors.

Pay attention to cleaning (deep cleaning of dust and bacteria on pores, the first line of defense to protect human body-skin).

Supplement nutrition, appropriate 100 micrograms of selenium supplement, selenium element is "natural antidote" to enhance resistance.

Air pollution prevention technology

The "Compilation of Advanced Technologies for the Prevention of Atmospheric Pollution" covers the control of smoke emissions from power plant boilers, the control of smoke emissions from industrial boilers and furnaces, the purification of typical toxic and harmful industrial exhaust gases, the control of exhaust emissions from motor vehicles, the purification of typical air pollutants in residential and public places, Key technologies in the eight areas of Medicom Environmental Technology (Shanghai) Co., Ltd.'s fugitive emission source control, atmospheric composite pollution monitoring simulation and decision support, and clean production, most of the selected technologies are derived from relevant national science and technology since the 11th Five-Year Plan Research results of planned projects or independent innovation.

Air Pollution Technology Catalog

I. Key technologies for power plant boiler flue gas emission control

1. Limestone / lime-gypsum wet flue gas desulfurization technology for coal-fired power plant boilers

Limestone or lime is used as a desulfurization absorbent. In the absorption tower, the absorbent slurry and the flue gas are fully contacted and mixed. The sulfur dioxide in the flue gas reacts with the calcium carbonate (or calcium hydroxide) in the slurry and the oxidized air in the chemical reaction It is removed, and the final desulfurization by-product is calcium sulfate dihydrate, that is, gypsum. The desulfurization efficiency of this technology is generally greater than 95% and can reach more than 98%; the concentration of SO emission is generally less than 100mg / m3 and can be less than 50mg / m3. The unit investment is approximately 150 ~ 250 yuan / kW; the operating cost is generally lower than 1.5 cents / kWh.

Scope of application: coal-fired power station boilers

2.Dual-phase rectification wet flue gas desulfurization technology in thermal power plant

The porous flake-shaped equipment installed between the inlet of the desulfurization absorption tower and the first spraying layer makes the flow field of the flue gas entering the absorption tower more uniform after passing through the equipment, and the flue gas and the slurry liquid formed on the equipment The impact of the film promotes the reaction between the gas and liquid two-phase media, so as to achieve the purpose of removing a part of SO2. This technology combines the spray tower and bubble tower technologies, which has a significant effect on improving the desulfurization efficiency and reducing the amount of slurry circulation. It is especially suitable for desulfurization and upgrading projects. The two-phase rectifier can improve the desulfurization efficiency of the system by 20% ~ 30%, and the overall desulfurization efficiency can reach more than 97%; the resistance is 600Pa ~ 700Pa, the unit investment is approximately 3 ~ 6 yuan / kWh, and the power consumption is reduced by about 250 ~ 850 kWh / h.

Scope of application: coal-fired power station boilers

3. Wet flue gas desulfurization technology for coal-fired boiler slag-gypsum

Using calcium carbide slag as a desulfurization absorbent, in the absorption tower, the absorbent slurry and the flue gas are fully contacted and mixed, and the sulfur dioxide in the flue gas reacts with the calcium hydroxide in the slurry and the oxidized air to be removed. The desulfurization by-product is calcium sulfate dihydrate, or gypsum. The desulfurization efficiency of this technology is generally greater than 95% and can reach more than 98%; the concentration of SO emissions is generally less than 100mg / Nm3 and can reach less than 50mg / Nm3; the unit investment is approximately 150 ~ 250 yuan / kW; the operating cost is generally less than 1.35 points / kWh.

Scope of application: coal-fired power station boilers

4. Circulating fluidized bed dry / semi-dry flue gas desulfurization and dust removal and multi-pollutant collaborative purification technology

Based on the principle of a circulating fluidized bed, through the recycling of materials, the absorbent, adsorbent, and circulating ash form a dense phase bed in the reaction tower, and water is sprayed into the reaction tower. Various pollutants in the flue gas A chemical reaction or physical adsorption occurs in the reaction tower; the flue gas purified by the reaction tower enters a downstream dust collector to further purify the flue gas. At this time, SO in the flue gas and almost all acidic components such as SO3, HCl, HF are absorbed and removed, and by-products such as CaSO3 · 1/2 HO and CaSO4 · 1/2 HO are formed. The desulfurization efficiency of this technology is generally greater than 90% and can reach more than 98%; SO2 emission concentration is generally less than 100mg / m3 and can reach less than 50mg / m3; the unit investment is approximately 150 ~ 250 yuan / kW; without adding any adsorbent and The operating cost under the condition of denitrant is generally 0.8 ~ 1.2 cents / kWh.

Scope of application: coal-fired power station boilers

Key Technologies for Controlling Flue Gas Emissions from Industrial Boilers and Kilns

1. Limestone-gypsum wet desulfurization technology

Limestone is used as a desulfurization absorbent. In the absorption tower, the absorbent slurry and the flue gas are fully contacted and mixed. The sulfur dioxide in the flue gas reacts with the calcium carbonate (or calcium hydroxide) in the slurry and the oxidized air to react. After removal, the final desulfurization by-product is calcium sulfate dihydrate, that is, gypsum. The desulfurization efficiency of this technology is generally greater than 95% and can reach more than 98%; the concentration of SO emissions is generally less than 100mg / m3 and can reach less than 50mg / m3; the unit investment is approximately 150 ~ 250 yuan / kW or 15 ~ 250,000 yuan / m2 Sintered area; operating cost is generally less than 1.5 cents / kWh.

Scope of application: industrial boiler / steel sintering flue gas

2. Calcium carbide slag-gypsum wet flue gas desulfurization technology

Using calcium carbide slag as a desulfurization absorbent, the operating cost in the absorption tower is generally lower than 1.35 cents / kWh.

Scope of application: industrial boilers

3.White mud-gypsum wet flue gas desulfurization technology

White mud is used as a desulfurization absorbent. In the absorption tower, the absorbent slurry and the flue gas are fully contacted and mixed. The sulfur dioxide in the flue gas reacts with the calcium carbonate (or sodium hydroxide) in the slurry and the oxidized air in a chemical reaction. After being removed, the final desulfurization by-product is calcium sulfate dihydrate, that is, gypsum. The desulfurization efficiency of this technology is generally greater than 95% and can reach more than 98%; the concentration of SO emissions is less than 100mg / Nm3 and can reach less than 50mg / Nm3; the unit investment is approximately 150 ~ 250 yuan / kW; the operating cost is generally lower than 1.35 cents / kWh.

Scope of application: industrial boilers

4. Circulating fluidized bed desulfurization technology for sintering flue gas of steel

The quicklime is digested and introduced into the desulfurization tower, and the desulfurization reaction with the incoming flue gas is performed in a fluidized state. After the flue gas is desulfurized, it enters the bag filter to remove dust, and then is discharged by the induced draft fan through the chimney. Part of it is returned to the fluidized bed for recycling through the circulating tank of absorbent. The desulfurization rate of this technology is slightly lower than that of the wet process. The absorbent has high utilization rate, compact structure, simple operation, and reliable operation. The desulfurization product is solid, no pulping system, no secondary pollution, small volume of the desulfurization tower, low investment, and difficult to block. . SO in the flue gas and almost all acidic components such as SO3, HCl, HF are absorbed and removed, and by-products such as CaSO3 · 1 / 2HO and CaSO4 · 1/2 HO are formed. The desulfurization efficiency of this technology is generally greater than 95% and can reach more than 98%; the concentration of SO emissions is generally less than 100mg / m3 and can reach less than 50mg / m3; the unit investment is approximately 150,000-200,000 yuan / square meter; no adsorption is added The operating cost of the catalyst and denitrifier is generally lower than 5 ~ 9 yuan / ton sinter.

Scope of application: steel sintering flue gas

5. New catalytic flue gas desulfurization technology

Using a new low-temperature catalyst, SO, HO, and O in the flue gas are selectively adsorbed in the micropores of the catalyst under the conditions of a flue gas emission temperature of 80 ~ 200 ° C, and are generated through the catalytic reaction of active components.

Scope of application: non-ferrous metals, petrochemicals, industrial boilers / kilns (including civilian kiln)

3. Key technologies for purifying typical toxic and harmful industrial waste gas

1. Volatile Organic Gases (VOCs) Recycling Desorption Diversion Recovery Adsorption Purification Technology

The activated carbon is used as an adsorbent, and the inert gas circulation heating desorption splitting condensation recovery process is used to purify and recover the organic gas. The recovery liquid can realize the recycling of organic matter through the subsequent refining process. The purification and recovery efficiency of organic gas components by this technology is generally greater than 90%, and can also reach more than 95%. The unit investment is approximately 90 ~ 240,000 yuan / thousand (m3h-1), and the cost of recovering organic matter is approximately 700 ~ 3000 yuan / ton

Scope of application: petrochemical, pharmaceutical, printing, surface coating, coating, etc.

2. Efficient adsorption-desorption- (heat storage) catalytic combustion VOCs treatment technology

VOCs in industrial waste gas are enriched with solid adsorption materials such as activated carbon fibers, particulate carbon, honeycomb carbon, and high temperature and high humidity monolithic molecular sieves, and the adsorption-saturated materials are subjected to enhanced desorption process to desorb VOCs enter the bed of high-efficiency catalytic materials for catalytic combustion or thermal storage catalytic combustion process treatment, and then degrade VOCs. The VOCs removal efficiency of this technology is generally greater than 95% and can reach more than 98%.

Scope of application: petroleum, chemical, electronics, machinery, painting and other industries

3. Activated carbon, bamboo charcoal coconut carbon adsorption and recovery of VOCs technology

Activated carbon (particulate carbon, activated carbon fiber, and honeycomb activated carbon) with excellent adsorption and analytical performance is used as an adsorbent to adsorb organic waste gas generated during the production process of the enterprise, and to recycle and reuse the organic solvent, thereby realizing resources for clean production and organic waste gas. Recycling. Exhaust air volume: 800 ~ 40000m3 / h, exhaust gas concentration: 3 ~ 150g / m3.

Scope of application: packaging and printing, petroleum, chemical, chemical drug manufacturing, coating, textile, container

4. Key Technologies for Motor Vehicle Emission Control

1. Catalytic exhaust purification technology for gasoline vehicles

The core components of automobile exhaust gas purifiers are prepared by adopting an optimized formula of a full Pd type three-effect catalyst and a positioning coating technology of a vacuum adsorption honeycomb catalyst. Vacuum coating technology can precisely control the amount of catalyst coating and effectively improve product consistency. The full Pd catalyst formula has a Pd content in the range of about 1 to 3 g / L depending on the engine model, which can reduce the cost by more than 50% compared with the ordinary Pd-Pt-Rh three-way catalyst used on the same engine. Purifiers produced by using the catalyst and coating technology can simultaneously purify CO, HC and NOx in automobile exhaust gas, and the purification effect can be greater than 95%, and the catalyst life span is more than 100,000 kilometers, which meets the exhaust emission standard requirements equivalent to the national VI and above.

Scope of application: Treatment of automobile exhaust pollutants

V. Key Technologies for Purifying Typical Air Pollutants in Houses and Public Places

1. Central air-conditioning air purification unit and indoor air purification technology

According to different places, adopting central air-conditioning systems with different wind disks and / or spaces, filters and purification components are installed, and various purification technologies such as filtration, adsorption, (photo) catalysis, and antibacterial / sterilization are integrated to achieve indoor temperature and air quality. Full adjustment.

Scope of application: indoor and indoor air purification

2. Purification technology of harmful microorganisms in indoor air

The layered material was developed as a carrier-supported antibacterial agent for silver ions, which solved the problem of discoloration of silver ions when used at high temperatures while maintaining good antibacterial properties. Developed organic-inorganic compound antibacterial spray, which has a good antibacterial effect on indoor harmful microorganisms, such as E. coli, Staphylococcus aureus, Candida albicans, and Legionella, and also has a good inhibitory effect on Bacillus subtilis.

Scope of application: indoor and indoor air purification

Key technologies for fugitive emission source control

1. Comprehensive dust suppression technology

It mainly includes key technologies such as bio-nano film dust suppression technology, cloud dust suppression technology and wet dust collection technology. Bio-nano-membrane is a double-ionization layer with nano-layer spacing, which can maximize the ductility of water molecules and has strong charge adsorption. Spraying bio-nano-membrane on the surface of materials can attract and agglomerate small particles of dust. It can be aggregated into large granular dust particles, and its own weight increases and settles. The dust removal rate of this technology can reach more than 99%, and the average operating cost is 0.05 ~ 0.5 yuan / ton. Cloud mist suppression technology is through high-pressure ion atomization and ultrasonic atomization, which can generate ultrafine dry mist of 1m ~ 100m; ultrafine dry mist particles are dense, which fully increases the contact area with dust particles. Water mist particles and dust particles collide and Aggregates to form agglomerates. The agglomerates become larger and heavier until they finally settle naturally to achieve the purpose of eliminating dust. The dry fog particles produced have a particle size of 30% to 40% below 2.5 m, which pollutes the fine particles of the atmosphere Control effect is obvious. Wet dust collection technology absorbs dust-adhered air through pressure drop, and removes dust under the dual effects of centrifugal force and the mixing of water and dust gas; key designs such as unique impellers can provide higher dust removal efficiency.

Scope of application: Suitable for the production, processing, transportation, loading and unloading of bulk materials, such as mines, construction, quarries, storage yards, ports, thermal power plants, iron and steel plants, garbage disposal and other places.

Key Technologies for Monitoring, Simulation and Decision Support of Atmospheric Compound Pollution

1. Rapid online monitoring system of atmospheric volatile organic compounds

After the ambient atmosphere is collected by the sampling system, it enters the concentration system. Under low temperature conditions, the volatile organic compounds in the atmosphere are frozen and captured in an empty capillary trapping column; then it is quickly desorbed by heating and enters the analysis system. After separation by the chromatography column Detected by FID and MS detectors, the system is also equipped with automatic backflush and automatic calibration procedures, and the entire process is automatically completed through software control. The main features of the system are: natural cascade electronic ultra-low temperature refrigeration system, self-developed temperature measurement technology, dual-path inert sampling system, deactivated empty capillary capture, dual column separation, FID and MS dual detector detection. The system can be used for continuous online monitoring and emergency detection (on-site sampling of sampling tanks). This system can detect 99 kinds of VOCs (hydrocarbons, halogenated hydrocarbons, oxygen-containing volatile organic compounds) in one sampling, and can meet the monitoring requirements of VOCs in China's ambient air for a long time.

Scope of application: Atmospheric environmental monitoring

2. On-line monitoring technology of atmospheric fine particles and their gaseous precursors

Utilizing a variety of fast interface combinations, an "online monitoring system for the integration of atmospheric fine particles and their gaseous precursors" with independent intellectual property rights has been designed and developed, enabling the simultaneous online monitoring of water-soluble chemical components of fine particles and their gaseous precursors Including: analysis of gaseous HCl, HONO, HNO3, HSO4, F-, Cl-, NO, NO3, SO4, and WSOC in aerosols, to achieve rapid online detection of various elements in fine particles in the atmosphere. Designed and developed a fine particle sample composition analysis device capable of different particle size segments, which is used to analyze the source and conversion process of atmospheric fine particles, provide basic data for collaborative control of atmospheric pollution areas, and provide for the formulation of regional atmospheric fine particle pollution control measures Scientific basis and monitoring technology.

Scope of application: Atmospheric environmental monitoring

3. Integrated on-line monitoring instrument and calibration technology for NOx and its photochemical products in the atmosphere

The photolysis technology and surface chemistry method are used to develop a technology for accurate measurement of NO2, combined with conventional chemiluminescence technology, to develop a technical system capable of accurately measuring NO, NO2, PAN and PPN. Integrate the developed dynamic zero chemiluminescence measurement NO module, photodegradation NO module and molybdenum catalytic conversion module to manufacture an integrated prototype, which can simultaneously and accurately measure NO, NO, NOy in atmospheric samples online. In order to assess the accurate calculation of the contribution of nitrogen-containing atmospheric active ingredients to O3 and the further evolution of its products, it provides reliable technical methods and instruments and equipment products suitable for national conditions.

Scope of application: Atmospheric environmental monitoring

4.Fast online monitoring technology of fine particles and ultrafine particles

Aiming at the technical requirements of three-dimensional on-line monitoring of regional atmospheric particulate matter, the in-situ rapid determination of physical and chemical characteristics of fine particles and ultra-fine particles in composite air pollution was carried out. Based on the "weighing method", the mass concentration monitor of the oscillating balance was completed to complete atmospheric PM2 .5 Real-time monitoring of mass concentration.

Scope of application: Atmospheric environmental monitoring

Key technologies for cleaner production

1. Clean combustion technology of replacing coal with coal water slurry

The coal-water slurry replacement oil clean combustion technology is to grind coal into fine powder and mix it with water and a small amount of additives to form a suspension-like high-concentration slurry. It is transported and stored in a fully enclosed manner like oil, pumped, and sprayed into the boiler furnace mist with a nozzle Suspension combustion, high combustion efficiency, it is a new technology of replacing oil with coal. The coal must be purified during the pulping process.

Scope of application: all kinds of power station boilers, industrial boilers, industrial kiln. ^[6-7]

Air pollution measures

Shanghai municipal and district governments will implement green power dispatching, key industrial enterprises to limit production or pollution or stop production, stop building construction outdoor operations and road excavation and renovation, stop operations at Yiyang Dockyard, strengthen road cleaning, and dump trucks Emergency mitigation measures such as banning of traffic, yellow-label vehicles, 30% suspension of official vehicles of party and government agencies and public institutions, prohibition of open burning of straw, and prohibition of fireworks and firecrackers. ^[8]