Tips on desulfurization

1. What are the good methods for desulfurization?

There are three major types of desulfurization processes: wet, semi-dry, and dry.

The most common desulfurization methods are calcium desulfurization and ammonia desulfurization. Calcium injection in the furnace, plasma, seawater desulfurization, etc. have a small market and are only suitable for special circumstances. Wet desulfurization technology is relatively mature, highly efficient and simple to operate.

The traditional limestone/lime-gypsum flue gas desulfurization process uses calcium-based desulfurizers to absorb sulfur dioxide and generate calcium sulfite and calcium sulfate. Due to their low solubility, they are easily dissolved in the desulfurization tower and pipelines. Scale and blockage will form inside. The double-alkali flue gas desulfurization technology was developed to overcome the shortcomings of the limestone-lime method that is prone to scaling.

With the gradual implementation of the new environmental protection law, the requirements for desulfurization efficiency are getting higher and higher. The only desulfurization methods that can meet the desulfurization efficiency are calcium method and ammonia method. However, calcium method desulfurization has complicated processes and clogging. , corrosion, sulfur gypsum accumulation and other problems, but it is still the current mainstream desulfurization method; the ammonia desulfurization method has a simpler process and does not produce any waste, and the ammonium sulfate produced can be used as compound fertilizer, but there is still a large investment , the problem of high operating costs. Ammonia desulfurization is the desulfurization method with the least problems at present, and it is also the mainstream trend in the future. The new integrated desulfurization and denitrification technology has been gradually improved and can meet the ultra-low emission standards of the new environmental protection law.

2. Flue gas desulfurization method

The lowest price is 0.27 yuan to become a library member and view the full content> Original publisher: FX Database Yan Zhongkaiyi, my country's "Twelfth Five-Year Plan" Tobacco Policy Background of Gas Desulfurization Sulfur dioxide emission reduction is one of the most important tasks of reducing emissions of major pollutants during my country’s “Twelfth Five-Year Plan” |

In March 2011, the "Twelfth Five-Year Plan" issued by the State Council listed sulfur dioxide as a binding indicator for total emission reduction control of major pollutants, with an 8% reduction target. In December 2011, the national "Twelfth Five-Year Plan" for environmental protection was announced. In order to achieve the 8% emission reduction target, sulfur dioxide emissions will be further reduced from 22.678 million tons in 2010 to 20.864 million tons in 2015.

At the same time, my country's coal consumption is expected to increase from 3 billion tons in 2010 to about 3.8 billion tons in 2015. Therefore, the task of reducing sulfur dioxide emissions is very arduous.

In November 2011, the State Council issued the "Opinions of the State Council on Strengthening Key Works on Environmental Protection" (Guofa [2011] No. 35), proposing that the total amount of sulfur dioxide emissions in the power industry should be controlled, and the fuel consumption should continue to be strengthened. To desulfurize coal power plants, new coal-fired units should simultaneously build desulfurization and denitrification facilities; implement total sulfur dioxide emission control in the steel industry, and strengthen the control of sulfur dioxide and nitrogen oxides in the cement, petrochemical, and coal chemical industries. Thermal power plants are the main emission source of sulfur dioxide in my country and are also the main battlefield for sulfur dioxide emission reduction in my country.

The revised "Air Pollutant Emission Standards for Thermal Power Plants" (GB13223-2011) was promulgated in September 2011 and will be implemented from 2012. It stipulates that the emission limit of sulfur dioxide for new coal-fired power plants is 100 mg/m3 (200 mg/m3 for high-sulfur coal areas); 200 mg/Nm3 for existing power plant renovations (400 for high-sulfur coal areas); coal-fired power plants in key areas The implementation of 50mg/Nm3 for coal-fired sulfur content is in the Ministry of Environmental Protection 42. The organic amine method was developed on the process of removing hydrogen sulfide in the chemical industry and can also reach (.

3. Desulfurization method< /p>

Flue gas desulfurization refers to the removal of sulfur oxides (SO2 and SO3) from flue gas or other industrial waste gases.

Contents 1 Process Introduction 2 Basic Principles 3 Process Method? Method Introduction? Dry desulfurization? Spray desulfurization? Coal ash desulfurization? Wet desulfurization 4 Process History 5 Anti-corrosion protection of desulfurization 1 Process Introduction Edit Flue gas desulfurization (FGD), [1] In FGD technology, according to the desulfurization agent Types can be divided into the following five methods: Calcium method based on CaCO3 (limestone), Magnesium method based on MgO, Sodium method based on Na2SO3, Ammonia method based on NH3, Organic base method Basic organic alkaline method.

[1] 2 Basic Principles Editor Chemical Principle: SO2 in flue gas is essentially acidic, [2] SO2 can be removed from flue gas by reacting with appropriate alkaline substances.

The most commonly used alkaline substances for flue gas removal are limestone (calcium carbonate), quicklime (calcium oxide, Cao) and hydrated lime (calcium hydroxide). Limestone is abundant and therefore relatively cheap. Both quicklime and hydrated lime are produced by heating limestone.

Other alkaline substances such as sodium carbonate (soda ash), magnesium carbonate and ammonia are sometimes used. The alkaline substance used reacts with the SO2 in the flue gas to produce a mixture of sulfites and sulfates (depending on the alkaline substance used, these salts may be calcium, sodium, magnesium or ammonium salts Salt).

The ratio between sulfite and sulfate depends on the process conditions, and in some processes all sulfite is converted to sulfate. The reaction between SO2 and alkaline substances occurs either in an alkaline solution (wet flue gas desulfurization technology) or on the wet surface of solid alkaline substances (dry or semi-dry flue gas desulfurization technology).

In the wet flue gas desulfurization system, the alkaline substance (usually an alkali solution, more often a slurry of alkali) and the flue gas meet in the spray tower. SO2 in the flue gas dissolves in water to form a dilute acid solution, which then neutralizes with alkaline substances dissolved in the water.

The sulfites and sulfates produced by the reaction precipitate from the aqueous solution, and the precipitation depends on the relative solubility of the different salts present in the solution. For example, calcium sulfate is relatively poorly soluble and therefore prone to precipitation.

Sodium sulfate and ammonium sulfate are much more soluble. In dry and semi-dry flue gas desulfurization systems, solid alkaline absorbent or the flue gas is sprayed into the flue gas flow through the alkaline absorbent bed to make it contact with the flue gas.

In either case, SO2 reacts directly with solid alkaline substances to generate the corresponding sulfites and sulfates. In order for this reaction to proceed, the solid alkaline material must be very loose or fairly finely divided.

In the semi-dry flue gas desulfurization system, water is added to the flue gas to form a liquid film on the surface of the alkaline material particles, and SO2 dissolves into the liquid film, accelerating the reaction with the solid reaction with alkaline substances. 3 Process Method Editor Method Introduction The commonly used commercial technology in the world is the calcium method, accounting for more than 90%.

According to the dry and wet state of the absorbent and desulfurization products during the desulfurization process, desulfurization technology can be divided into wet method, dry method and semi-dry (semi-wet) method. Wet FGD technology uses a solution or slurry containing absorbent to desulfurize and process desulfurization products in a wet state. This method has the advantages of fast desulfurization reaction speed, simple equipment, and high desulfurization efficiency. However, it is generally prone to severe corrosion, high operation and maintenance costs, and It is easy to cause secondary pollution and other problems.

The desulfurization absorption and product treatment of dry FGD technology are all carried out in a dry state. This method has no sewage and waste acid discharge, less equipment corrosion, and no obvious cooling or purification of flue gas during the purification process. It has the advantages of high rear smoke temperature, conducive to the diffusion of chimney exhaust, and less secondary pollution. However, it has problems such as low desulfurization efficiency, slow reaction speed, and bulky equipment. Semi-dry FGD technology refers to a process in which the desulfurizer is desulfurized in a dry state and regenerated in a wet state (such as a water-washed activated carbon regeneration process), or the desulfurization product is desulfurized in a wet state and the desulfurization product is processed in a dry state (such as spray drying). Gas desulfurization technology.

In particular, the semi-dry method, which desulfurizes in a wet state and processes desulfurization products in a dry state, has the advantages of fast wet desulfurization reaction speed and high desulfurization efficiency, and the dry method has no waste water. The advantages of waste acid discharge and desulfurization products being easy to handle have attracted widespread attention. According to the use of desulfurization products, it can be divided into two types: discard method and recovery method.

At present, flue gas desulfurization methods commonly used at home and abroad can be roughly divided into three categories according to their processes: wet disposal process, wet recovery process and dry process. Among them, the application of frequency converters in equipment has made a huge contribution to energy conservation.

[3] Dry desulfurization Dry flue gas desulfurization process This process was used for power plant flue gas desulfurization in the early 1980s. Compared with the conventional wet scrubbing process, it has the following advantages: lower investment cost; The desulfurization product is dry and mixed with fly ash; there is no need to install a demister and reheater; the equipment is not prone to corrosion, scaling and blockage.

Its disadvantages are: the utilization rate of the absorbent is lower than that of the wet flue gas desulfurization process; the economy is poor when used for high-sulfur coal; the mixing of fly ash and desulfurization products may affect comprehensive utilization; and the control requirements for the drying process are very high.

Spray desulfurization spray dry flue gas desulfurization process spray dry flue gas desulfurization (referred to as dry FGD) was a desulfurization process first jointly developed by the American JOY Company and the Danish NiroAtomier Company in the 1970s. It was developed in the mid-term and rapidly promoted and applied in the power industry. This process uses atomized lime slurry to contact the flue gas in the spray drying tower. The lime slurry reacts with SO2 to generate a dry solid reactant, which is finally collected by the dust collector together with fly ash.

Our country has conducted a pilot test of rotary spray dry flue gas desulfurization at Baima Power Plant in Sichuan Province, and gained some experience to optimize parameters for the use of rotary spray dry flue gas desulfurization on 200~300MW units. Design provides the basis. Coal ash desulfurization Fly ash dry flue gas desulfurization technology Japan began to study dry flue gas desulfurization technology using fly ash as a desulfurization agent in 1985. By the end of 1988, it completed industrial practical tests, and the first unit was put into operation in early 1991. Fly ash dry desulfurization equipment can process flue gas 644000Nm3/h.

Its characteristics: the desulfurization rate is as high as over 60% and the performance is stable, reaching the general wet desulfurization performance level; the cost of the desulfurization agent is low; the water consumption is small, no drainage treatment and exhaust reheating are required, and the total equipment cost is It is 1/4 lower than the wet desulfurization method; the coal ash desulfurization agent can be reused; there is no slurry, easy maintenance, and the equipment is stable.

4. What are the major categories of commonly used coal-fired flue gas desulfurization methods

Common desulfurization technologies Editor Flue gas desulfurization (FGD) is an effective desulfurization method used on a large scale in the industrial industry method.

According to the form of sulfide absorbent and by-products, desulfurization technology can be divided into three types: dry method, semi-dry method and wet method. The dry desulfurization process mainly uses solid absorbents to remove SO2 in the flue gas. Generally, fine limestone powder is sprayed into the furnace to decompose it into CaO when heated, absorbing the SO2 in the flue gas to generate CaSO3, which is removed together with fly ash. Collect it or discharge it through the chimney.

Wet flue gas desulfurization uses a gas-liquid reaction of liquid absorbent under ionic conditions to 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 during treatment, which reduces secondary pollution; the disadvantage is that the desulfurization efficiency is low and the equipment is bulky.

Wet desulfurization uses liquid absorbent to wash the flue gas to remove SO2. The equipment used is relatively simple, easy to operate, and has high desulfurization efficiency; however, the temperature of the flue gas after desulfurization is lower, and the corrosion of the equipment is more serious than that of the dry method. [1] Limestone (lime)-gypsum wet flue gas desulfurization process Limestone (lime) wet desulfurization technology has been widely used in the field of wet FGD because the absorbent is cheap and easy to obtain.

The reaction mechanism using limestone as absorbent is: Absorption: SO2(g)→ SO2(L)+H2O → H++HSO3- → H+ +SO32- Dissolution: CaCO3(s)+H+ → Ca2 ++HCO3-neutralization: HCO3- +H+ →CO2(g)+H2O oxidation: HSO3-+1/2O2→SO32-+H+SO32- +1/2O2→SO42-crystallization: Ca2++SO42- +1 /2H2O →CaSO4·1/2H2O(s) This process is characterized by high desulfurization efficiency (>95%), high absorbent utilization rate (>90%), adaptability to high-concentration SO2 flue gas conditions, and low calcium-sulfur ratio ( Generally <1.05), desulfurization gypsum can be comprehensively utilized, etc. The disadvantages are high infrastructure investment costs, large water consumption, and corrosive desulfurization wastewater.

Seawater flue gas desulfurization seawater flue gas desulfurization process is a desulfurization method that uses the alkalinity of seawater to remove sulfur dioxide in flue gas. The desulfurization process does not require the addition of any chemicals and does not produce solid waste. The desulfurization efficiency is >92% and the operation and maintenance costs are low.

After the flue gas is removed by the dust collector, it is sent to the gas-to-gas heat exchanger by the booster fan to cool down, and then sent to the absorption tower. In the desulfurization absorption tower, it comes into contact with a large amount of seawater from the circulating cooling system. The sulfur dioxide in the flue gas is removed by the absorption reaction, and the seawater is oxidized and then discharged.

The flue gas after removing sulfur dioxide is heated by the heat exchanger and discharged from the flue. The seawater flue gas desulfurization process is restricted by region and is only suitable for projects with abundant seawater resources. It is especially suitable for thermal power plants where seawater is used as circulating cooling water. However, it is necessary to properly solve the problems inside the absorption tower, the drainage pipe ditch of the absorption tower and the rear flue. , anti-corrosion issues of chimneys, aeration tanks and aeration devices.

The process flow is shown in Figure 1. Spray drying process Spray drying process (SDA) is a semi-dry flue gas desulfurization technology, and its market share is second only to the wet method.

This method is to spray the absorbent slurry Ca(OH)2 in the reaction tower. While absorbing SO2 in the flue gas, the mist droplets are evaporated by the hot flue gas to generate solids and are captured by the dust collector. When the calcium-sulfur ratio is 1.3~1.6, the desulfurization efficiency can reach 80%~90%.

Semi-dry FGD technology has the general characteristics of both dry and wet methods. Its main disadvantage is that it uses slaked lime milk as the absorbent, the system is prone to scaling and clogging, and special equipment is required to prepare the absorbent, so the investment cost is relatively high; the desulfurization efficiency and absorbent utilization rate are not as high as the limestone/gypsum method.

Spray drying technology is widely used in small and medium-capacity units burning low-sulfur and medium-sulfur coal. In China, a medium-sized test device was built at Baima Power Plant in January 1990.

Later, many units also adopted this desulfurization process, and the technology has been basically mature. Electron beam flue gas desulfurization process (EBA method) Electron beam radiation technology desulfurization process is a dry desulfurization technology, which is a high-tech technology that combines physical methods and chemical methods.

The process of this process is composed of exhaust pre-dust removal, flue gas cooling, ammonia injection, electron beam irradiation and by-product capture. The flue gas discharged from the boiler enters the cooling tower after being coarsely filtered by the dust collector. Cooling water is sprayed in the cooling tower to cool the flue gas to a temperature suitable for desulfurization and denitrification (about 70°C).

The dew point of flue gas is usually about 50℃. The flue gas after passing through the cooling tower flows into the reactor, and a mixture of ammonia, compressed air and soft water close to the stoichiometric ratio is injected. The amount of ammonia added depends on the SOx and NOx concentrations. After electron beam irradiation, SOx and NOx Under the action of free radicals, the intermediates sulfuric acid and nitric acid are generated.

Then sulfuric acid and nitric acid neutralize with the existing ammonia to produce a mixture of powdery granular ammonium sulfate and ammonium nitrate. The desulfurization rate can reach more than 90%, and the denitrification rate can reach more than 80%.

In addition, sodium-based, magnesium-based and ammonia can also be used as absorbents. The mixed particles of ammonium sulfate and ammonium nitrate generated by the general reaction are separated and captured by the by-product dust collector, and the purified smoke The gas is pressurized and discharged to the atmosphere.

5. What are the flue gas desulfurization methods?

The main industrial technologies are: ① Wet lime/limestone-gypsum method This method uses lime or limestone slurry to absorb SO2 in the flue gas , generate hemihydrate calcium sulfite or re-oxidize to gypsum.

Its technology is highly mature and its desulfurization efficiency is stable, reaching more than 90%. It is currently the main method at home and abroad. ②Spray drying method This method uses lime milk as an absorbent and sprays it into the desulfurization tower. After desulfurization and drying, the powdery desulfurization slag is discharged. It is a semi-dry desulfurization method with a desulfurization efficiency of about 85%. The investment is higher than the wet limestone-gypsum method. Low.

Currently mainly used in the United States. ③Absorption 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. ④ Calcium injection in the furnace - humidification activation desulfurization method. This method is a desulfurization technology that directly sprays powdery calcium desulfurization agent (limestone) into the furnace of the combustion boiler. It is suitable for medium and low sulfur coal boilers, and the desulfurization efficiency is about 85%. .

6. Principle and process flow of wet desulfurization technology

Principle and process of wet desulfurization technology: Flue gas enters the wet absorption tower of the desulfurization device, and the top-down The sprayed alkaline limestone slurry droplets are in counter-current contact, and the acidic oxides SO2 and other pollutants HCL, HF, etc. are absorbed, and the flue gas is fully purified; the slurry after absorbing SO2 reacts to generate CaSO3, which is forced to oxidize in place, Crystallization generates CaSO4?2H2O, and after dehydration, a commercial-grade desulfurization by-product—gypsum—is obtained, ultimately achieving comprehensive treatment of sulfur-containing flue gas.

Extended information: Technical advantages: 1. Technical design that integrates smoke elimination, desulfurization, denitrification, dust removal, and dehydration at the same time. The structure is simple and compact, the process flow is reasonable, and the interior is not easy to be scaled and blocked. Designed without water; 2 The effective area utilization rate inside the equipment is 100%, and the smoke and dust are completely dissolved in the alkaline aqueous solution during the entire purification process to achieve efficient mass transfer; 3 Using high-efficiency external splash spray atomization design, the equipment There are no wearing parts inside to ensure the most efficient desulfurization and dust removal; 4 It constitutes the most complete mass transfer process between flue gas and alkaline solution to ensure the most efficient desulfurization and dust removal; 5 The manufacturing materials can be naturally abrasion resistant. Made of granite, it solves the long-term shortcomings of environmental protection equipment such as non-wear resistance, non-corrosion resistance, and short lifespan; 6. Ensure certain liquid vaporization, stable sulfur dioxide absorption rate, and control the dilute alkali with a pH value of about 10 and 25% liquid as a sulfur dioxide absorbent. It is not easy to volatilize and has low loss. It achieves high desulfurization efficiency and stable effect, and effectively solves the problem of dust accumulation and scaling inside the equipment. 7. The smooth flue gas channel design inside the equipment and the direction of the flue gas have no dead ends, which reduces the thermal resistance of the flue gas. , to ensure the effect under the designed working conditions, without affecting the operation of combustion equipment such as boilers; 8. The simple and efficient principle of cyclic double alkali desulfurization makes full use of the waste alkali produced in the factory, treats waste with waste, comprehensively utilizes it, and reduces operating costs. , closed-circuit recycling of alkaline water, 100% wastewater utilization, and no secondary wastewater pollution discharge

Reference: Baidu Encyclopedia - Desulfurization Technology.

7. Types of desulfurization processes

The limestone-gypsum desulfurization process is the most widely used desulfurization technology in the world, and is used in thermal power plants in Japan, Germany, and the United States. About 90% of flue gas desulfurization devices use this process.

Its working principle is: Add limestone powder to water to make a slurry as an absorbent and pump it into the absorption tower to fully contact and mix with the flue gas. The sulfur dioxide in the flue gas and the calcium carbonate in the slurry are pumped from the lower part of the tower. The incoming air undergoes an oxidation reaction to generate calcium sulfate. After the calcium sulfate reaches a certain saturation level, it crystallizes to form dihydrate gypsum. The gypsum slurry discharged from the absorption tower is concentrated and dehydrated to make the moisture content less than 10%, and then sent to the gypsum silo for stacking by conveyor. The desulfurized flue gas passes through a demister to remove mist droplets, and then is heated by a heat exchanger. After heating up, it is discharged into the atmosphere through the chimney.

Since the absorbent slurry in the absorption tower is repeatedly circulated through the circulation pump to contact the flue gas, the absorbent utilization rate is very high, the calcium-sulfur ratio is low, and the desulfurization efficiency can be greater than 95%. System components: (1) Limestone storage and transportation system (2) Limestone slurry preparation and supply system (3) Flue gas system (4) SO2 absorption system (5) Gypsum dehydration system (6) Gypsum storage and transportation system (7) Slurry discharge system (8) Process water system (9) Compressed air system (10) Wastewater treatment system (11) Oxidation air system (12) Electrical control system Technical features: (1) Absorbent has a wide range of application: various absorbers can be used in FGD devices Agents, including limestone, lime, magnesite, waste soda solution, etc.; 2. Wide application range of fuels: suitable for tail gas treatment of boilers burning coal, heavy oil, Oreo oil, petroleum coke and other fuels; 3. Changes in fuel sulfur content Strong range adaptability: can handle flue gas with fuel sulfur content up to 8%; (4) Strong adaptability to unit load changes: can meet the stable operation of the unit within the load change range of 15~100%; (5) High desulfurization efficiency: general Greater than 95%, up to 98%; ⑹. Patented tray technology: effectively reduces the liquid/gas ratio, which is conducive to uniform air flow in the tower, saves material and energy consumption, and facilitates the maintenance of internal parts of the absorption tower; ⑺. High absorbent utilization rate : The calcium-sulfur ratio is as low as 1.02~1.03; ⑻. High purity of by-products: commercial grade gypsum with a purity of more than 95% can be produced; ⑼. High dust removal efficiency of coal-fired boiler flue gas: reaching 80%~90%; ⑽. Cross Spray pipe layout technology: It is beneficial to reduce the height of the absorption tower.

Recommended scope of application: ⑴. Medium and large-scale newly built or renovated units of 200MW and above; ⑵. The sulfur content of coal is 0.5~5% and above; ⑶. The required desulfurization efficiency is above 95%. ; ⑷ In areas where limestone is abundant and gypsum is widely utilized, the spray drying desulfurization process uses lime as the desulfurization absorbent. The lime is digested and water is added to make slaked lime milk. The slaked lime milk is pumped into the atomization device located in the absorption tower. , in the absorption tower, the absorbent that is atomized into fine droplets is mixed and contacted with the flue gas, and chemically reacts with the SO2 in the flue gas to generate CaSO3, and the SO2 in the flue gas is removed. At the same time, the moisture brought in by the absorbent is quickly evaporated and dried, and the flue gas temperature decreases.

The desulfurization reaction products and unused absorbent are taken out of the absorption tower with the flue gas in the form of dry particles, and enter the dust collector to be collected. The desulfurized flue gas is discharged after being dusted by a dust collector.

In order to improve the utilization rate of desulfurization absorbent, part of the dust collector collection is generally added to the pulping system for recycling. This process has two different atomization forms to choose from, one is rotating spray wheel atomization, and the other is gas-liquid two-phase flow.

The spray drying desulfurization process has the characteristics of mature technology, relatively simple process flow, and high system reliability. The desulfurization rate can reach more than 85%. This process has a certain application range (8%) in the United States and some Western European countries.

Desulfurization ash can be used for brick making and road construction, but is mostly discarded to ash yards or backfilled in abandoned mines. The ammonium phosphate fertilizer method flue gas desulfurization technology is a recovery method and is named after its by-product is ammonium phosphate.

The process mainly consists of adsorption (activated carbon desulfurization and acid production), extraction (dilute sulfuric acid decomposes phosphate rock to extract phosphoric acid), neutralization (ammonium phosphate neutralizing liquid preparation), absorption (ammonium phosphate liquid desulfurization and fertilizer production) ), oxidation (ammonium sulfite oxidation), concentration and drying (solid fertilizer preparation) and other units. It is divided into two systems: flue gas desulfurization system - after the flue gas passes through a high-efficiency dust collector, the dust content is less than 200mg/Nm3, and a fan is used to increase the flue pressure to 7000Pa. First, the venturi tube sprays water to cool down and regulate humidity. Then it enters the four-tower activated carbon desulfurization tower group in parallel (one of the towers is periodically switched and regenerated) to control the primary desulfurization rate to be greater than or equal to 70%, and produce sulfuric acid with a concentration of about 30%. The flue gas after primary desulfurization enters The secondary desulfurization tower uses ammonium phosphate slurry to wash and desulfurize, and the purified flue gas is discharged after mist separation.

Fertilizer preparation system - In a conventional single-tank multi-slurry extraction tank, the dilute sulfuric acid decomposed phosphate rock powder (P2O5 content greater than 26%) obtained at the same stage of desulfurization is filtered to obtain dilute phosphoric acid (its concentration More than 10%), add ammonia for neutralization to obtain ammonium phosphate, which is used as a secondary desulfurizer. The slurry after secondary desulfurization is concentrated and dried to make ammonium phosphate compound fertilizer. The calcium injection in the furnace plus tail flue gas humidification and activation desulfurization process is based on the calcium injection desulfurization process in the furnace and adds a humidification section at the tail of the boiler to improve the desulfurization efficiency.

This process mostly uses limestone powder as the absorbent. The limestone powder is sprayed into the furnace temperature zone of 850~1150℃ by pneumatic force. The limestone is heated and decomposes into calcium oxide and carbon dioxide. Calcium oxide reacts with sulfur dioxide in the flue gas to form Calcium sulfite. Since the reaction takes place between the gas and solid phases, it is affected by the mass transfer process, so the reaction speed is slow and the absorbent utilization rate is low.

In the tail humidification activation reactor, humidification water is sprayed into the mist, and contacts with unreacted calcium oxide to generate calcium hydroxide, which then reacts with sulfur dioxide in the flue gas. When the calcium-sulfur ratio is controlled at 2.0~2.5, the system desulfurization rate can reach 65~80%.

Since the addition of humidifying water causes the flue gas temperature to drop, the outlet flue gas temperature is generally controlled to be 10~15°C higher than the dew point temperature. The humidifying water is rapidly evaporated due to the heating of the flue temperature, and the unreacted absorbent , the reaction product is discharged with the flue gas in a dry state and is collected by the dust collector. This desulfurization process has been applied in Finland, the United States, Canada, France and other countries. The maximum single unit capacity using this desulfurization technology has reached 300,000 kilowatts.

The flue gas circulating fluidized bed desulfurization process consists of absorbent preparation, absorption tower, desulfurization ash recycling, dust collector and control system. This process generally uses dry slaked lime powder as the absorbent.

8. What are the contents of desulfurization safety training

Safety education is an important part of enterprise safety management work. It is an important measure to fundamentally eliminate people’s unsafe behaviors and is also a preventive measure. and one of the important means to control accidents.

Only by doing a good job in safety education and training in the enterprise can other safety work and the safety production of the enterprise be carried out smoothly. In order to make the company's education and training in 2010 planned, focused and purposeful, the following annual safety education and training plan has been formulated.

1. Basic ideas

(1) Strengthen safety awareness education of “safety first, prevention first”. Safety awareness education is to help employees correct matters and improve their understanding of the importance of safe production through in-depth and detailed ideological work on employees. On the basis of improving ideological awareness, we can correctly understand and actively implement relevant safety production rules and regulations, strengthen our own awareness of protection, do not operate in violation of regulations, do not violate labor discipline, and achieve "three no harms": no harm to ourselves, no harm Hurt others and not be hurt by others.

At the same time, safety awareness education should also be strengthened for managers at all levels of the company (including leaders, company departments, workshop managers, technicians, etc.) to ensure that they take the lead when working and start from caring. Starting from the perspective of protecting people's lives and health, we attach great importance to safe production and do not give orders in violation of regulations.

(2) Incorporate safety education throughout the entire production process, strengthen the enthusiasm of all employees to participate and the long-term nature of safety education. Achieve "all-staff, comprehensive, and whole-process" safety education. Because production and safety are an inseparable unity, safety education is required wherever there is production.

(3) Carry out safety education through multiple channels and in various forms. The form of safety education should be adapted to local conditions, different from person to person, flexible and multi-purpose, and try to adopt a method that is in line with people's cognitive characteristics, interesting and easy to accept. According to the specific situation of our company, the main forms of safety education include the following aspects:

(1) Meeting format. Mainly include: safety knowledge lectures, symposiums, report meetings, advanced experience exchange meetings, accident lesson on-site meetings, etc.

(2) Hanging form. Mainly include: safety promotion banners, slogans, signs, pictures, safety promotion boards, etc.

(3) Audio and video products. Mainly include: safety education CDs, safety lecture videos, etc.

(4) On-site observation and demonstration format. Mainly include: demonstration of safe operation methods, fire drills, demonstration of first aid methods for electric shock, etc.

(4) Strictly implement the company’s three-level safety education system and eliminate the phenomenon of directly taking up the job without the third-level safety education. For new employees and new workers entering the factory, three-level safety education (including factory-level, workshop-level, and team-level safety education) should be strictly required. The learning content includes safety technical knowledge, equipment performance, operating procedures, safety systems, and strictly prohibited matters. Only those who pass the assessment can enter the operating position. The assessment results must be recorded. The time for level 3 safety education shall not be less than 24 hours.

2. Main training content plan:

Time-themed education target training staff

Whole-process three-level safety education class to strengthen the safety of new employees Quality safety officers for new factory employees, etc.

In January, publicity and publicity on national safety laws and regulations strengthened employees’ legal awareness. All employee safety officers

In February, safety production management knowledge and safety production technology expertise Knowledge

Classes are held to strengthen employees’ safety awareness. Safety officers for all employees

March job safety operating procedures; Classes are held to strengthen employees’ safety operations. Safety officers for workshop personnel

4 The monthly safety knowledge education meeting for each position and publicity made the personnel in each position familiar with their position knowledge. Operator safety officers at each position

The May safety education meeting for company managers strengthened the safety awareness of managers and strengthened the role of leading and exemplary company management Personnel Safety Officer

Fire safety knowledge training and education in June and July, summer safety knowledge education lectures, publicity, etc. make employees understand the importance of fire prevention and how to put out fires and other common sense

Prevent heat stroke and All employee fire guards, safety officers, etc. in electric shock accidents

Analysis of typical accidents and emergency rescue cases in August; Publicity to strengthen employee safety awareness and ability to handle emergencies All employee safety officers

Safety production rules and regulations and labor disciplines in September; safety officers for all employees, including electricians, welders, drivers, etc., will attend classes to ensure safe production

Safety education for special operations personnel will be held in October to strengthen the safety skills and quality of special operations personnel< /p>

In November, safety education and publicity on the use of labor protection supplies and on-site guidance ensured that employees knew the role of wearing labor protection supplies and how to wear them. All employee safety officers

Summary of 2009 annual safety training activities in December, Develop a safety training plan for the next year

3. Requirements

1. The specific training plan should be formulated one month before the training and submitted to the leadership for approval, and all parties involved in the training should be notified in a timely manner Relevant personnel are prepared.

2. After the training, a comprehensive summary of the training effects should be made.

3. Safety training and education activities that cannot be held as scheduled must be reported to superiors in a timely manner, explaining the specific time and reasons for holding them.

4. At the end of the year, write a summary report of the annual training and education activities, put forward the aspects of lack of training this year, and the aspects that should be paid attention to in future education, and formulate a safety training and education plan for the next year.