Development of wet desulfurization, wet desulfurization Principle and comparison of dry desulfurizat

With the continuous improvement of sulfur dioxide emission standards for thermal power plants in China, and the sulfur content of coal combustion has also increased compared with before, the existing wet desulfurization units can no longer meet the relevant requirements. In order to further improve the desulfurization efficiency, it is necessary to add LY-WS desulfurization additives, LY-WS desulfurization catalysts, LY-WS desulfurization synergists, etc. in the process of desulfurization, so that the sulfur dioxide emission standards meet the national requirements.

China's flue gas desulfurization business has just started, although it has a huge market prospects, but the task is also quite arduous, at present, the most mature treatment SO2 technology in China is limestone wet flue gas desulfurization technology.

The raw materials and processes of desulfurization are different, the main component of dry and semi-dry desulfurizer is an emulsion desulfurizer (calcium hydroxide) prepared by quicklime and water, and the flue gas is sprayed counter-flow or downstream, and gypsum is desulfurized after dust removal and solid **. On the whole, the desulfurization efficiency of dry and semi-dry desulfurization is very low, and the general desulfurization efficiency can only reach about 70%. Wet desulfurization is also divided into many kinds, the general principle is that the flue gas is washed by alkaline solution, the SO2 in the flue gas is absorbed by the solution, and the sulfite solution is nearly saturated to oxidize to generate sulfate, and the desulfurization by-product is generated after crystallization.

There is also the reduction of sub-salts to produce sulfur elements, which are filtered to the by-product sulfur. The efficiency of wet desulfurization is very high, and it can reach 100% without considering the cost of desulfurization, but absorbents such as ammonia desulfurization increase, the amount of fugitive ammonia increases, nitrogen oxides destroy the atmosphere, and it is not advisable to pursue desulfurization alone!

At the same time, corrosion is inevitable, which is the biggest problem in the desulfurization industry, and it has been difficult to overcome so far. The reason for the corrosion is that the composition of the flue gas can be complex, the sulfate generated is a strong acid under acidic conditions, the chloride ions brought by the flue gas will corrode the stainless steel, the fluoride ions will corrode the glass (instrument), and the alkaline added by desulfurization will also corrode the steel ......

The technology is not mature at all, and all three methods are bullshit! Any one will corrode the desulfurization equipment and related equipment in a short time, especially the wet desulfurization!

Regarding wet desulfurization, I can guarantee that the tower body will be used for more than 10 years, and it will not corrode or scale.

Principle and process of wet desulfurization process technology:

The flue gas enters the wet absorption tower of the desulfurization unit and is in countercurrent contact with the alkaline limestone slurry droplets sprayed from top to bottom, and the acid oxide SO2 and other pollutants HCl and HF are absorbed, and the flue gas can be fully purified. After absorbing SO2, the slurry reacts to generate CaSO3, which is forced to oxidize and crystallize to generate CaSO4 2H2O through the wheel, and after dehydration, the commercial-grade desulfurization by-product - gypsum sedan is obtained, and finally the comprehensive treatment of sulfur-containing flue gas is realized.

Answer]: 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, and the equipment used is relatively simple, easy to operate, and has high desulfurization efficiency; However, the flue gas temperature after desulfurization is lower, and the corrosion of the equipment is heavier than that of the dry method. Dress up with envy.

The differences between wet desulfurization and dry desulfurization are as follows:

1. Different process properties: dry desulfurization refers to those processes that always keep the flue gas dry in the desulfurization process, except for calcium spraying in the furnace, quicklime is required as an absorbent. Wet desulfurization refers to the process in which the flue gas is in a saturated state or part of the time in the desulfurization process, and the absorbent used for the wet process is mainly limestone, ammonia, magnesium oxide, etc. can also be used as an absorbent.

2. Different technical characteristics: wet desulfurization refers to the desulfurization and desulfurization product treatment of the reactant in the slurry state. The main equipment of wet desulfurization includes spray tower and liquid column tower desulfurization system; Dry desulfurization refers to the use of eggplant brigade lime as the desulfurization absorbent, and the desulfurization treatment is carried out in the form of spray.

In the absorption tower, the lime reagent made by digesting and adding water is atomized into fine droplets, which are mixed with the flue gas and in contact, so that the SO2 in the flue gas undergoes a chemical reaction into CaSO3, and the SO2 in the flue gas is removed.

3. Different raw materials: the main ingredient of dry desulfurizer is an emulsion desulfurizer (calcium hydroxide trembling stool) prepared by quicklime and water. Wet desulfurization mainly uses limestone or gypsum slurry to wash the flue gas and react it with SO2 to form calcium sulfite (CaSO3).

The separated calcium sulfite can be discarded, or it can be forced into the air for oxidation, and some additives can be added in the form of gypsum**.

Summary. Pro, the general desulfurizer dosage is usually determined by the molar ratio of the desulfurizer. Molar ratio refers to the molar ratio of desulfurizer to sulfur dioxide in flue gas.

Common desulfurizers include limestone (CaCO3), lime (CaO), etc. According to different types of desulfurizers, their molar ratios are generally between. The specific amount of desulfurizer can be calculated according to the following formula:

Desulfurizer dosage = sulfur dioxide concentration in flue gas flue gas volume flow rate Molar ratio It should be noted that the determination of desulfurizer dosage also needs to consider other factors, such as the reaction rate of desulfurizer, injection mode and other details. Therefore, in the specific wet desulfurization engineering design, detailed process analysis and experimental research should be carried out to determine the optimal amount of desulfurizer.

Wet desulfurization is a common flue gas desulfurization method, and the dosage of debroading and osmotic sulfur needs to be calculated according to the specific situation. Generally, the design dosage of desulfurizer for wet desulfurization depends on the following factors:1

the concentration of sulphur dioxide in flue gas; 2.the flow rate of sulphur dioxide in the flue gas; 3.type and content of absorbent; 4.

Absorb the dosage of the agent.

Pro, the general amount of desulfurizer is usually determined by the desulfurizer brother Songerbi. Molar ratio refers to the molar ratio of desulfurizer to sulfur dioxide in flue gas. Common desulfurizers include limestone (CaCO3), lime (CaO), etc.

According to different types of desulfurizers, their molar ratios are generally between. The specific calculation of the amount of desulfurizer can be carried out according to the following formula: the amount of desulfurizer = the concentration of sulfur dioxide in the flue gas The volume flow rate of the flue gas The molar ratio It should be noted that the determination of the amount of desulfurizer also needs to consider other factors, such as the reaction rate of the desulfurizer, the injection mode and other details.

Therefore, in the specific design of the wet desulfurization project, detailed process analysis and experimental research should be carried out to determine the optimal amount of desulfurizer.

The concentration of quiet dioxide in the flue gas is 2000mg m, the amount of flue gas flow is 250,000m, the main component of the desulfurizer is calcium carbonate, the content is 65%, the desulfurization efficiency is 98%, and the amount of desulfurizer is designed? Imitation oak omen.

Pro, the dosage of desulfurizer is designed to:

Hello! We're happy to answer for you! In wet oxidation desulfurization, sulfate in solution is reduced to sulfur dioxide, and the reduction reaction is usually carried out in a natural environment (i.e., before the denitrification reaction).

Therefore, chemically speaking, there is a slight sequence between denitrification and desulfurization. However, in practice, some factors lead to the early regeneration of desulfurization, such as:1

Sudden change in feed water quality: When the water quality of the feed macro only changes greatly, it may cause the sulfate that reacts slowly with the oxidant to be completely reduced in a short time, resulting in early desulfurization and regeneration. 2.

Ununiform catalyst concentration: If the concentration of the catalyst is uneven, the reduction reaction rate in some areas may be faster, resulting in early local desulfurization regeneration. 3.

High oxidant concentration: If the oxidant is used in excess, it may lead to the rapid reduction of ridge sulfate and early desulfurization and regeneration. 4.

Changes in reaction conditions, such as temperature, pressure, flow, etc., may also lead to early desulfurization regeneration. Therefore, in practice, we need to control the time of desulfurization and regeneration by adjusting the feed water quality, controlling the catalyst concentration, optimizing the oxidant dosage, and maintaining stable masking reaction conditions.