Gas refers to the poisonous and harmful gases discharged by human beings in the process of production and life. In particular, chemical plants, iron and steel plants, pharmaceutical plants, coking plants and oil refineries emit large odor of waste gas, which seriously pollutes the environment and affects human health. The following is my introduction to the causes of waste gas pollution. I hope it can help you.
Industrial waste gas discharged by various production enterprises is an important source of air pollutants. If a large amount of industrial waste gas is discharged into the atmosphere without treatment and reaching the standard, it will inevitably reduce the quality of atmospheric environment, bring serious harm to human health and cause huge losses to the national economy. After the toxic and harmful substances in industrial waste gas can enter the human body through the respiratory tract and skin, long-term low concentration or short-term high concentration exposure can cause temporary and permanent diseases of human respiratory, blood, liver and other systems and organs, especially benzopyrene polycyclic aromatic hydrocarbons can cause direct carcinogenesis to human body, which has attracted great attention of human beings.
Industrial waste gas includes organic waste gas and inorganic waste gas. Organic waste gas mainly includes various hydrocarbons, alcohols, aldehydes, acids, ketones and amines; Inorganic waste gas mainly includes sulfur oxides, nitrogen oxides, carbon oxides, halogens and their compounds. China has adopted a pollutant emission control system for air pollution.
First, the harm of air pollution to human body and health. Air pollutants harm the human body mainly through three ways: first, they are injured after contact with the human body surface, second, they are poisoned by eating food and water containing air pollutants, and third, they suffer from various serious diseases after inhaling polluted air. From the following table, we can see that various air pollutants enter the human body through various ways, and their impact on the human body is multifaceted. Moreover, its harm is also extremely serious.
2. Air pollution endangers the survival and development of organisms. Air pollution endangers the survival and development of organisms mainly through three ways: first, poisoning or depletion of organisms, second, slowing down the normal development of organisms, and third, reducing the resistance of organisms to diseases and pests. The long-term exposure of plants to atmospheric pollution during the growth period damaged the leaf surface and weakened photosynthesis; It damages the internal structure and withers the plant until it dies. Among all kinds of harmful gases, sulfur dioxide, chlorine and hydrogen fluoride are the most harmful to plants. The damage of air pollution to animals is mainly respiratory tract infection and eating air polluted food. Among them, arsenic, fluorine, lead and molybdenum are the most harmful. Air pollution makes animals weak and even die. Air pollution also kills soil microorganisms in the form of acid rain, acidifying the soil, reducing soil fertility and endangering crops and forests.
III. corrosion of air pollution to objects. Air pollutants have a corrosive effect on instruments, equipment and buildings. Such as rust spots on metal buildings and severe weathering of ancient cultural relics.
IV. the impact of air pollution on the global atmospheric environment. The development of air pollution has gone beyond national boundaries and its harm is all over the world. The impact on the global atmosphere is obviously manifested in three aspects: one is the destruction of the ozone layer, the other is the corrosion of acid rain, and the third is global warming.
I. condensation recovery method
The organic waste gas is directly introduced into the condenser, and valuable organic matter can be recovered through adsorption, absorption, plate disintegration and separation. This method is applicable to the working conditions of high concentration, low temperature and small air volume of organic waste gas. It needs auxiliary refrigeration equipment. It is mainly used in pharmaceutical and chemical industries, and is rarely used by printing enterprises.
II. Direct combustion method
Combustion of auxiliary fuels such as gas or fuel oil is used to heat the mixed gas to decompose harmful substances into harmless substances under the action of high temperature; This method has the advantages of simple process and small investment. It is suitable for waste gas with high concentration and small air volume, but it has high requirements for safety technology and operation.
III. catalytic combustion method
The waste gas is heated and converted into harmless and odorless carbon dioxide and water through catalytic combustion; The method has the advantages of low ignition temperature, energy saving, high purification rate, convenient operation, small floor area and large investment. It is suitable for organic waste gas with high temperature or high concentration.
IV. adsorption method
(1) direct adsorption method: organic waste gas can be adsorbed by activated carbon with a purification rate of more than 95%. The equipment is simple and the investment is small, but the activated carbon is replaced frequently, which increases the working procedures such as loading and unloading, transportation and replacement, resulting in an increase in operating costs.
(2) adsorption recovery method: use fiber activated carbon to adsorb organic waste gas, and use superheated steam to blow back after it is close to saturation for desorption regeneration; This law requires the provision of the necessary amount of steam.
(3) new adsorption catalytic combustion method: this method combines the advantages of adsorption method and catalytic combustion method, adopts new adsorption material (honeycomb activated carbon) for adsorption, introduces hot air for desorption and analysis when it is close to saturation, and the waste gas after desorption is introduced into catalytic combustion bed for flameless combustion to completely purify it, and the hot gas is recycled in the system, greatly reducing energy consumption. At present, this method has the characteristics of low investment and stable operation, and is suitable for the treatment of waste gas in China. It has the characteristics of low investment and reliable operation.