Dry desulfurization

Dry desulfurization

Dry flue gas desulfurization refers to the use of powdered or granular absorbents, adsorbents or catalysts to remove sulfide-containing gases from flue gas. Desulfurization and dust collector manufacturers

Basic Information:

Definition of dry flue gas desulfurization: CaCO3 injected into the furnace is calcined at high temperature and decomposed into CaO, which reacts with SO2 in flue gas to generate calcium sulfate; SO2 is converted into ammonia sulfate or sulfuric acid by electron beam irradiation or activated carbon adsorption, collectively referred to as dry flue gas desulfurization. Flue gas desulfurization technology.

Advantages and disadvantages:

It has the advantages of simple process, no sewage and acid treatment problems, low energy consumption, especially the high temperature of flue gas after purification, which is conducive to the diffusion of chimney exhaust, and will not produce "white smoke" phenomenon. The gas does not need secondary heating and is less corrosive; its disadvantage is that the desulfurization efficiency is low, the equipment is large, the investment is large, the floor space is large, and the operating technology requirements are high.

NID technology:

NID (Novel Integrated Desulphurization) dry flue gas desulfurization technology is a new generation of flue gas dry desulfurization technology creatively developed on the basis of semi-dry desulfurization devices. It draws on the desulfurization principle of semi-dry technology and overcomes this problem. The disadvantages of this technology using pulping systems. Therefore, it has the characteristics of low investment and compact equipment, and is suitable for units of 300MW and below.

Technical features:

1) The NID technology adopts the integrated design of quicklime (CaO) digestion and ash circulating humidification to ensure that the freshly digested high-quality slaked lime (Ca(OH)2) is immediately put into the circulating desulfurization reaction;

2) The circulating ash is used to carry moisture and form a water film on the surface of the dust particles. The thin layer of water film on the surface of the dust particles evaporates in the flue gas flow in an instant, forming an ideal reaction environment with suitable temperature and humidity in a very short time. At the same time, it also overcomes the sticky wall problem that may occur in the traditional semi-dry desulfurization reactor;

3) Since the time for establishing an ideal reaction environment is reduced, it is possible to greatly reduce the total reaction time, which can effectively reduce the height of the desulfurization reactor;

4) The flue gas flows at high speed in the reactor, and the whole device has compact structure, small volume and reliable operation. The load adaptability of the device is good;

5) Desulfurization by-products are dry, and the system produces no water. The final product has good fluidity and is suitable for pneumatic conveying. After desulfurization, the flue gas can be directly discharged without reheating;

6) The requirements for absorbents are not high and can be widely obtained.

7) By reducing the size of the absorption tower and reducing the floor space and avoiding the use of complex and expensive digestion and preparation systems, the initial investment and operating costs are greatly reduced;

8) The desulfurization efficiency is high, and the desulfurization efficiency can reach more than 90%.

technical parameter:

Calcium-sulfur ratio (Ca/S): <1.4

Material cycle times: 30—150

Desulfurization efficiency: 70%-80%.

desulfurization

desulfurization

SO2 removal efficiency: >99%

Dust removal efficiency: >99.9%

System availability: >1%

Schematic diagram of NID flue gas circulating fluidized bed desulfurization technology

CFB technology:

CFB flue gas desulfurization technology has the characteristics of high desulfurization efficiency, low construction investment, small footprint, simple structure, easy operation and low operating cost.

Technical Features

1) The solid absorbent particles stay for a long time;

2) The heat and mass transfer between the solid absorbent and SO2 is strong;

3) The desulfurization efficiency is high, and the desulfurization efficiency can reach more than 90% for high-sulfur coal (sulfur content above 3%);

4) As the bed material is recycled, the utilization rate of the absorbent is improved; under the same desulfurization efficiency, compared with the traditional semi-dry method, the absorbent can be saved by 30%;

5) The operation is simple, the operation is reliable, and the reaction temperature can be lowered to the vicinity of the dew point of the flue gas;

6) The structure is compact, the circulating fluidized bed reactor does not need a lot of space, and it can achieve large-scale;

7) Desulfurization products are discharged in solid state;

8) No pulping system;

9) The electrostatic precipitator of the renovation project does not need to be modified.

Technology:

Calcium-sulfur ratio (Ca/S): <1.4

Material cycle times: 30—100

Desulfurization efficiency: >80%

SO2 removal efficiency: >99%

Dust removal efficiency: >99.9%

System availability: >98%

Other technologies:

In-furnace calcining circulating fluidized bed flue gas desulfurization is based on the flue gas circulating fluidized bed desulfurization technology. At the same time, it can cooperate with boiler energy-saving renovation to improve thermal efficiency.

Technical Features

1) The heat and mass transfer between the solid absorbent and SO2 is strong, and the particles in the bed collide, causing collision and abrasion on the surface of the absorbent particles, continuously removing the reaction products on the surface of the reactant, and exposing a new reaction surface;

2) The particles can be recycled for multiple times through the back-mixing of the bed material in the bed and the external separator, so as to improve the utilization rate of the desulfurizer;

3) The integrated design with the electrostatic precipitator ensures the simplicity of the equipment;

4) Limestone is used as desulfurizer, which has very strong adaptability;

5) Simultaneous with the boiler energy-saving renovation, it can improve the efficiency of the boiler and further reduce the operating cost of the desulfurization system.

Technology:

Calcium-sulfur ratio (Ca/S): <1.4

Material cycle times: 30—100

Desulfurization efficiency: >80%

SO2 removal efficiency: >99%

Dust removal efficiency: >99.9%

System availability: >98%