There are significant differences between semi-dry desulfurization and wet desulfurization in many aspects. Here's a concrete comparison of the two:
Desulfurization efficiency: The semi-dry desulfurization efficiency is usually stable at about 80%, and if the efficiency needs to be further improved, it is necessary to reduce the flue gas approach temperature difference, increase the CA S and spray water, but these adjustments will have an adverse impact on downstream equipment such as dust collectors, induced draft fans, etc. In contrast, the wet desulfurization efficiency can generally operate stably above 95%, which is highly adaptable to environmental protection requirements, and is easy to adjust and control when the sulfur content of flue gas changes, so that the desulfurization efficiency remains stable.
Calcium-sulfur ratio: In the semi-dry process, when the desulfurization rate is 90%, the calcium-sulfur ratio is usually 13～1.between 5. The calcium-sulfur ratio of wet desulfurization is generally 101～1.05.
Power consumption: The power consumption of the semi-dry method is usually 0 of the capacity of the unit5%～1.0%, when the desulfurization efficiency is about 80%, the power consumption is about 06%。The power consumption of wet desulfurization is 10%～1.5%。
Impact on electrostatic precipitator: The semi-dry method increases the calcium-sulfur ratio with the change of desulfurization rate, and the load of the electrostatic precipitator increases sharply. When the sulfur content of flue gas changes, in order to ensure the desulfurization rate, or to improve the desulfurization efficiency in order to meet the continuous improvement of environmental protection requirements, the above measures to reduce the temperature difference of flue gas approach, increase the amount of water sprayed and the ratio of calcium and sulfur will lead to low-temperature corrosion of the electrostatic precipitator, and the ash discharge will be easy to bond, and in serious cases, the normal operation of the device will be affected. But the wet law doesn't have an electrostatic precipitator, so it has no effect.
Impact on the unit: the semi-dry method will lead to the deposition of solid matter in the tower due to fault and power outage and other reasons, and the deposition of solid matter needs to be cleaned up for restart, because there is no bypass, when the rear electrostatic precipitator and ash return system are blocked for maintenance, the unit will be out of operation. The wet rule has no effect because it is an independent operating system with a bypass.
Adaptability to the load of the unit: The change of semi-dry load will cause the change of flue gas velocity, which will affect the desulfurization reaction and the operation of the device.
In general, there are significant differences between semi-dry desulfurization and wet desulfurization in terms of desulfurization efficiency, calcium-sulfur ratio, power consumption, impact on electrostatic precipitator and unit, and adaptability to unit load. These differences make the selection of a desulfurization method a combination of specific environmental requirements, equipment conditions and economic factors.