Boiler flue gas desulfurization

Your post would be more appropriate for discussion in the boiler area.

Using activated carbon-based materials for adsorption yields much better results.

It is recommended to try ammonia-based desulfurization! ～ The ammonia-based desulfurization method has the following advantages: (Our factory is currently using this method, and the results are quite good.) (1) The desulfurization tower is less prone to scaling. Due to the higher reactivity of ammonia, and owing to the chemical properties of the sulfurous acid solution, scaling can be avoided. (2) The ammonia method is more suitable for desulfurizing medium- and high-sulfur coals. In the limestone-gypsum process, the higher the sulfur content of the coal, the more limestone is required, resulting in higher costs. In contrast, with the ammonia process, due to the high value of the by-products, a higher sulfur content leads to an increased production of sulfuric acid as a by-product, which makes the process more economical. (3) The by-product sulfurous acid generated during the ammonia-based desulfurization process can be comprehensively utilized to produce solid sulfuric acid for use as fertilizer; there is no wastewater discharge and no secondary pollution. It is in line with the concepts of a circular economy and the development direction of the environmental protection industry. (4) Low energy consumption, as no temperature reduction or increase is required during the desulfurization process, and the resistance of the desulfurization tower is low. Taking the flue gas desulfurization of a 200MW unit at the Nanhai Power Plant in Guangdong as an example, the electricity consumption for desulfurization accounts for 0.04% of the total power generation. (5) There is no need to install a bypass flue (except as required by the user); when the supply of absorbent is stopped, the reaction tower can be used as a flue, without affecting the normal operation of the unit and boiler. (6) The desulfurization device is efficient and convenient; the ammonia-based flue gas desulfurization method features strong activity and a fast reaction rate. The desulfurization agent is a clear ammonia solution, and all desulfurization by-products are highly soluble; there is no scaling or wear, which facilitates automatic control via PLC and DCS systems. The flue gas can enter the desulfurization tower for the desulfurization reaction without being cooled, and the treated flue gas can be emitted at a temperature above its dew point without being heated again; the desulfurization efficiency is greater than 95%. The entire desulfurization process is simple; it can be operated with only the appropriate supervision staff. (7) Low resistance: the resistance of the desulfurization tower is around 450 Pa. When constructing a desulfurization system in a thermal power plant, it is possible to make full use of the excess pressure available from the original exhaust fan; generally, there is no need to install a booster fan or replace the exhaust fan – in case it is necessary, only the impeller of the existing exhaust fan needs to be upgraded. (8) It requires minimal floor space: the desulfurization tower for a 220 T/h boiler has a diameter of 6–7 meters, while that for a 410 T/h boiler has a diameter of 7–8 meters. One tower can be installed per boiler, or one tower can be used per exhaust fan outlet. In terms of desulfurization setup, this system currently has the smallest floor area required in China. The floor area required for the desulfurization equipment is related to the size of the boiler; boilers with a capacity of 220T/h to 1000T/h require approximately 200m2 to 500m2 of space. Treatment of desulfurization by-products: the area required for the ammonium sulfate production process is around 500 m2. (9) The equipment investment is low; including the equipment for the comprehensive utilization of by-products, the investment per kilowatt for desulfurization in thermal power plants ranges from 200 to 300 yuan. Technical specifications for ammonia-based desulfurization: Service life of the unit: >20 years; annual operating hours of the desulfurization unit: >7200 hours; load range of the desulfurization unit: 25％–100％; desulfurization efficiency: ≥98％. Ammonia content in flue gas after desulfurization: ≤10ppm. Dust content in flue gas after desulfurization:

Thank you! Is ammonia-based desulfurization connected in series after the flue gas dust removal equipment, and how is the ammonia content in the flue gas after the reaction controlled?

Our company also has flue gas from conventional coal-fired boilers that needs to be desulfurized; we are considering the use of caustic soda or ammonia water. The ammonia water method requires higher operational standards and can also lead to secondary pollution. The utilization of the absorbent solution in the caustic soda method is another issue – please offer some suggestions!

Is there any requirement for the dust content in flue gas before wet desulfurization?

Let’s discuss the double-alkali method; it’s being used quite a lot these days.

What is the role of sodium citrate in desulfurization?