Hydrogen sulfide removal technology before combustion

    The sulfur in the gas originates from the coal used for gasification, primarily existing in the form of H2S. Approximately 80% of the sulfur in the coal used for gasification is converted into H2S and enters the gas. Assuming that the sulfur content in the coal used for gasification is 1%, about 2-3g/Nm3 of H2S will be formed and transferred into the gas after gasification. If the H2S in the gas is burned and converted into SO2, the concentration will be around 2.6g/m3, which is significantly higher than the national emission concentration limit for SO2. Therefore, whether from the perspective of meeting environmental emission standards or ensuring product quality for enterprises, this part of H2S in the gas must be removed.

    Sulfur dioxide removal technology after combustion

Desulfurization after combustion, also known as flue gas desulfurization (FGD), can be divided into the following five methods based on the type of desulfurizing agent in FGD technology: the calcium method based on CaCO3 (limestone), the magnesium method based on MgO, the sodium method based on Na2SO3, the ammonia method based on NH3, and the organic alkali method based on organic alkali. The calcium method is the most commonly used commercial technology worldwide, accounting for over 90% of the market share.

Based on the dry or wet state of the absorbent and desulfurization products during the desulfurization process, desulfurization technologies can be categorized into wet, dry, and semi-dry (semi-wet) methods. Wet FGD technology employs solutions or slurries containing absorbents to desulfurize and treat desulfurization products in a wet state. This method boasts advantages such as fast desulfurization reaction rates, simple equipment, and high desulfurization efficiency. However, it commonly faces issues such as severe corrosion, high operation and maintenance costs, and potential for secondary pollution.

The desulfurization absorption and product treatment in dry FGD technology are carried out in a dry state. This method has the advantages of no sewage or waste acid discharge, less equipment corrosion, no significant temperature drop during the purification process, high flue gas temperature after purification, facilitating chimney exhaust dispersion, and less secondary pollution. However, it has problems such as low desulfurization efficiency, slow reaction rate, and large equipment size.

Semi-dry FGD technology refers to flue gas desulfurization technology where the desulfurizing agent is used in a dry state for desulfurization and in a wet state for regeneration (such as the water-washing activated carbon regeneration process), or where the desulfurizing agent is used in a wet state for desulfurization and the desulfurization products are treated in a dry state (such as the spray drying method). Especially, the semi-dry method, where desulfurization is carried out in a wet state and the desulfurization products are treated in a dry state, has attracted widespread attention due to its advantages of both fast reaction speed and high desulfurization efficiency of wet desulfurization, as well as the advantages of no sewage and waste acid discharge and easy treatment of desulfurization products in dry methods. According to the usage of desulfurization products, it can be divided into two methods: disposal and recovery.

Our company primarily focuses on the dual-alkali integrated desulfurization and denitrification technology

The double alkali method involves first using a soluble alkaline solution as an absorbent to absorb SO2, and then regenerating the absorbent solution with lime milk or lime. It is called the double alkali method because different types of alkalis are used in the absorption and absorbent solution treatment processes. The sodium-calcium double alkali method involves using sodium carbonate or sodium hydroxide solution to absorb SO2 from flue gas, and then treating the absorbent solution with lime or hydrated lime as the alkali solution. The regenerated absorbent solution is sent back to the absorption tower for recycling. Since sodium alkali solution is used as the absorbent, there are no issues of scaling or slurry blockage. Additionally, the absorption rate of sodium salts is faster than that of calcium salts, requiring a much lower liquid-to-gas ratio, which can save on power consumption.

Therefore, the sodium-calcium double alkali desulfurization process is adopted in this project.

Flue gas denitrification technology (SCR system process)

  The complete SCR denitration device mainly consists of a urea dissolving storage tank, urea conveying system, metering system, injection system, and control system.

 When urea is selected as the reducing agent for the SCR denitrification system, it needs to be dissolved and a urea solution with a concentration of 5%-10% should be used. Based on the actual situation on site, this project sets up a urea dissolution storage tank to dissolve urea particles into a 5%-10% urea solution for storage and use.

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合同编号	使用单位	设备型号	所属行业
HZ17010	南京工业大学	HCGY10-SX15	College
HZ17032	太原餐厨	HCGY10-SX15	methane
HE2106	唐山派尔氧化铝烟气脱硝	HCGY10-SX150