What industries is the desulfurization project suitable for? Is it mainly chimney desulfurization?

The principle of desulfurization. Dissolution process of limestone: CaCO3+2H+ Ca2++CO2+H2O

Absorption process of SO2:

so2+h2o→h2so3

H2SO3 H++HSO3- (at low pH) (lower part of the absorption zone) H2SO3 2H++SO32- (at high pH) (upper part of the absorption zone) Ca2++2HSO3- Ca(HSO3)2Ca2++SO32- CaSO3

Oxidation of reaction products:

2ca(hso3)2+o2→caso4+2h2o2caso3+o2→2caso4

Crystallization to form gypsum:

caso4+2h2o→

Desulfurization is divided into many processes according to different principles, mainly based on physical and chemical methods. The basic physical ones are mainly adsorption. Such as activated carbon fiber, activated coke desulfurization.

Based on chemistry, it is mainly SO3 and basic groups for chemical reactions. The effect of going out SO2 has been achieved.

Desulfurization is applicable to a wide range of industries, as long as the sulfur content of the emitted flue gas exceeds the standard, it must be desulfurized, the industry is too wide to be specific. There are many kinds of desulfurization processes, but basically they are desulfurized in the desulfurization tower or reactor.

Pre-combustion: coal preparation technology, microbial desulfurization.

Combustion: briquette sulfur fixation, circulating fluidized bed combustion.

Post-combustion: flue gas desulfurization technology (wet, dry, semi-dry) Coal conversion: coal gasification, liquefaction, coal-water slurry technology.

Wet after combustion.

--Limestone-gypsum method.

--Ammonia method. --Magnesium oxide method.

--Alkaline waste method (calcium carbide slag method, white mud method, waste alkali method) -- seawater desulfurization method.

--Double alkali method.

--Ammonium phosphate fertilizer method, zinc oxide method, basic aluminum sulfate method, etc.

Dry --- calcium injection in the furnace.

--Calcium spraying in the furnace and humidification and activation of flue gas at the tail.

--Electron beam irradiation, pulsed corona, charged dry absorbent injection semi-dry method--- circulating fluidized bed method.

--Spray drying method.

There are generally two types of desulfurization: wet desulfurization and dry desulfurization.

Flue gas desulfurization is divided into three types of desulfurization processes: wet, semi-dry and dry.

The wet desulfurization technology is relatively mature, with high efficiency and simple operation. The traditional limestone-gypsum flue gas desulfurization process uses calcium-based desulfurizer to absorb sulfur dioxide to generate calcium sulfite and calcium sulfate, which are easy to form scaling and blockage in the desulfurization tower and pipeline due to their small solubility. The double alkali flue gas desulfurization technology is developed to overcome the shortcomings of the limestone-lime method.

With the increase of motor vehicles, vehicle exhaust has become a major source of air pollution, and acid rain has become more frequent, seriously endangering buildings, soil and human living environment. Therefore, countries around the world have put forward higher oil quality standards to further limit the sulfur content, olefin content and benzene content in oil products to better protect the living space of human beings.

With the increase of sulfur** processing and the popularization of catalytic cracking of heavy oil, the phenomenon of excessive sulfur content and poor stability of oil products is becoming more and more serious. Due to the limitations of capital and hydrogen sources of hydrodesulfurization, it is of great significance for small and medium-sized refineries to carry out research on non-hydrorefining. This paper briefly introduces the progress and future development trend of non-hydrodesulfurization technology.

Here's how:

1. Limestone powder is added to water to make a slurry and pumped into the absorption tower as an absorbent to fully contact and mix with the flue gas, the sulfur dioxide in the flue gas and the calcium carbonate in the slurry and the air blown in from the lower part of the tower are oxidized to generate calcium sulfate, and after the calcium sulfate reaches a certain saturation, it crystallizes to form gypsum dihydrate.

2. The gypsum slurry discharged from the absorption tower is concentrated and dehydrated to make its water content less than 10%, and the conveyor is sent to the gypsum storage silo for stacking, and the flue gas after desulfurization is removed by the mist eliminator, and then discharged into the atmosphere by the chimney after heating and heating by the heat exchanger.

3. NID principle stone: the ash powder enters the reactor after being digested by the lime digester (LDH), and the SO in the flue gas undergoes a chemical reaction to generate CASO and CASO, and the SO in the flue gas is removed.

At present, there are generally three desulfurization methods: pre-combustion, combustion and post-combustion desulfurization. With the development of industry and the improvement of people's living standards, the thirst for energy is also increasing, and SO2 in coal-fired flue gas has become the main cause of air pollution. Reducing SO2 pollution has become a top priority in today's atmospheric environment management.

Many flue gas desulfurization processes have been widely used in industry, and they also have important practical significance for the treatment of exhaust gas of various boilers and incinerators.

The desulfurization absorption and product treatment of dry FGD technology are carried out in a dry state, which has the advantages of no sewage waste acid discharge, light corrosion degree of equipment, no obvious cooling of flue gas in the purification process, high flue gas temperature after purification, conducive to chimney exhaust diffusion, and less secondary pollution, but there are problems such as low desulfurization efficiency, slow reaction speed and large equipment.

Semi-dry FGD technology refers to the flue gas desulfurization technology in which the desulfurizer is desulfurized in the dry state and regenerated in the wet state (such as the water-washed activated carbon regeneration process), or the desulfurization is desulfurized in the wet state and the desulfurization products are treated in the dry state (such as the spray drying method).

In particular, the semi-dry method of desulfurization in wet state and treatment of desulfurization products in dry state has attracted widespread attention because of its advantages of fast reaction speed and high desulfurization efficiency of wet desulfurization, as well as the advantages of dry waste-free waste acid discharge and easy treatment of desulfurization products. According to the use of desulfurization products, it can be divided into two types: discarding method and ** method.

1.Coal-fired power plants and industrial boilers: In coal-fired power plants and industrial boilers, the flue gas contains large amounts of sulfur oxides and nitrogen oxides. In order to reduce the emission of air pollutants, flue gas desulfurization and denitrification treatment is required.

2.Iron and steel smelting: In the process of steel smelting, the flue gas contains harmful gases such as hydrogen sulfide, sulfur oxide and nitrogen oxides. Desulfurization and denitrification of these gases can help reduce air pollution and acid rain.

3.Cement industry: In the process of cement production, the flue gas contains harmful gases such as sulfates and nitrogen oxides. Flue gas desulfurization and denitrification treatment helps to reduce environmental pollution and improve production efficiency.

4.Coal chemical industry and chemical industry: Coal chemical industry and some chemical processes also produce waste gases containing sulfur-oxygen bridging chemicals and nitrogen oxides. Desulfurization and denitrification technologies can be used to reduce the emission of these harmful gases.

5.Oil refining industry: In the oil refining process, the flue gas contains sulfur oxides such as hydrogen sulfide and sulfate, as well as nitrogen oxides. Desulfurization and denitrification technology can be used to treat these exhaust gases and reduce the impact on the environment.

Flue gas desulfurization and denitrification is an important means to reduce sulfur oxide and nitrogen oxide emissions, which is mainly used in heavy industries such as electric power, chemical industry, iron and steel, and non-ferrous metals. The main reason why these industries need flue gas desulfurization and denitrification is that they are the main ones for sulfur oxide and nitrogen oxide emissions, and these substances will cause serious pollution to the environment.

Chemical industry: A large number of chemical raw materials are used in the chemical production process, and these raw materials will produce a large amount of sulfur oxides and nitrogen oxides in the traces of the combustion process.

Iron and steel industry: A large amount of coke is used in the steel production process, and coke produces large amounts of sulfur oxides and nitrogen oxides during combustion.

Non-ferrous metal industry: The production process of non-ferrous metals requires the use of a large number of chemical raw materials, which produce large amounts of sulfur oxides and nitrogen oxides during the combustion process.

In short, flue gas desulfurization and denitrification is an important means to reduce sulfur oxide and nitrogen oxide emissions, and is widely used in heavy industries such as electric power, chemical industry, orange and steel, and non-ferrous metals.

Flue gas desulfurization and denitrification are mainly needed by these industries, such as: glass kilns, thermal power plants, cement plants, coking plants, petrochemical regiments, iron and steel plants, etc.

Among them, the desulfurization and denitrification methods have better effects in the world

The better desulfurization methods are:SDS sodium bicarbonate desulfurization

The better denitrification methods are:PNCR polymer denitrification

The main technologies of industrialization are:

Wet lime Limestone-gypsum method This method uses lime or limestone slurry to absorb SO2 in flue gas to generate calcium sulfite hemihydrate or reoxidize into gypsum. Its technology has a high degree of maturity and stable desulfurization efficiency, reaching more than 90%, which is the main method at home and abroad.

Spray drying method This method uses lime milk as an absorbent to spray into the desulfurization tower, and is discharged as a powdery desulfurization slag after desulfurization and drying, which is a semi-dry desulfurization method, with a desulfurization efficiency of about 85%, and the investment is lower than that of the wet limestone-gypsum method. At present, it is mainly used in the United States.

The absorption and regeneration method mainly includes ammonia method, magnesium oxide method, double alkali method and W-L method. The desulfurization efficiency can reach about 95%, and the technology is relatively mature.

Calcium spraying in the furnace - humidification and activation desulfurization method This method is a desulfurization technology that sprays powdered calcareous desulfurizer (limestone) directly into the furnace of combustion boilers, which is suitable for medium and low sulfur coal boilers, and the desulfurization efficiency is about 85%.

Xinhua Energy currently uses more desulfurization processes in the following areas: dry desulfurization, semi-dry desulfurization, and ammonia desulfurization.

Dry desulfurization is the use of desulfurizer ultrafine powder and flue gas full mixing, contact, under the action of catalyst and accelerator, with the flue gas SO2 rapid reaction. Moreover, in the reactor, flue and bag filter, the desulfurizer ultrafine powder has been reacting with the SO2 in the flue gas. The reaction is fast and sufficient, and the by-product Na2SO4 can be produced in less than 2 seconds.

Through the cloth bag ** by-product, it is used as a chemical product.

The semi-dry process uses a desiccant containing lime (calcium oxide) or dried slaked lime (calcium hydroxide) to absorb sulphur dioxide, both of which can be used, as well as fly ash containing appropriate alkaline.

The wet ammonia desulfurization process is a high-efficiency, low-energy wet desulfurization method. The process uses a certain concentration of ammonia as the absorbent, and the gas and the absorbent produce sufficient gas-liquid phase reaction in the desulfurization tower, so as to remove the SO2 in the gas and obtain ammonium sulfite intermediate products, and at the same time, the ammonium sulfite is directly oxidized to produce ammonium sulfate by drumming into oxidizing air, so as to realize the resource utilization of desulfurization by-products.

If the total amount of SO2 removal is large, reaching the scale of 1 tonne day, wet process is possible.

Comparatively cheaper; If the total amount of SO2 removal is small and the flue gas is relatively clean, such as the flue gas of the heating furnace and hot blast furnace of the steel mill, it is recommended to use the Roche dry method, although the agent is a little more expensive, but it is reliable, trouble-free and clean. In recent years, the Roche dry process has been rapidly promoted in the steel industry.

Flue gas desulfurization (FGD) is an effective desulfurization method for large-scale applications in the industrial industry. According to the form of sulfide absorbent and by-products, desulfurization technology can be divided into three types: dry, semi-dry and wet. The dry desulfurization process mainly uses a solid absorbent to remove SO2 in the flue gas, generally sprays the limestone fine powder into the furnace to decompose it into CAO by heating, absorbs the SO2 in the flue gas, generates CASO3, and collects it with fly ash in the dust collector or discharged it through the chimney.

Wet flue gas desulfurization is the use of liquid absorbent under ionic conditions of gas-liquid reaction, and then remove SO2 in the flue gas, the equipment used in the system is simple, the operation is stable and reliable, and the desulfurization efficiency is high. The biggest advantage of dry desulfurization is that there is no discharge of waste water and waste acid in the treatment, which reduces secondary pollution; The disadvantage is that the desulfurization efficiency is low and the equipment is huge. Wet desulfurization uses liquid absorbent to wash the flue gas to remove SO2, the equipment used is relatively simple, easy to operate, and the desulfurization efficiency is high; However, the flue gas temperature after desulfurization is lower, and the corrosion of the equipment is more serious than that of the dry method.

Limestone (lime)-gypsum wet flue gas desulfurization process.

Limestone (lime) wet desulfurization technology has been widely used in the field of wet FGD due to the low and easy availability of absorbents.

The reaction mechanism with limestone as an absorbent is as follows:

Absorption: SO2(G) SO2(L)+H2O H++HSO3- H+ +SO32-

Dissolve: CaCO3(S)+H+Ca2++HCO3-

Neutralization: HCO3- +H+ CO2(g)+H2O

Oxidation: HSO3-+1 2O2 SO32-+H+

so32- +1/2o2→so42-

Crystallization: Ca2++SO32- +1 2H2O CaSO3·1 2H2O(S).

The process is characterized by high desulfurization efficiency (>95%), high utilization rate of absorbent (>90%), can adapt to high concentration SO2 flue gas conditions, low calcium-sulfur ratio (general< and desulfurization gypsum can be comprehensively utilized. The disadvantages are high infrastructure investment costs, large water consumption, and corrosive desulfurization wastewater.