Abstract: Desulfurization catalyst can also be called desulfurization synergist, which refers to the catalyst used in the desulfurization process. Most desulfurization catalysts are prepared with γ-alumina as a carrier and cobalt, molybdenum, nickel, etc. as active components. Desulfurization catalysts can increase the gas-liquid mass transfer rate of sulfur dioxide, strengthen the absorption of sulfur dioxide and increase the desulfurization rate. Let’s learn about desulfurization catalysts. 1. What is a desulfurization catalyst?
Desulfurization catalyst is also called desulfurization synergist and desulfurization additive. Using polymer substances as the main raw materials, through physical and chemical processing, intensification or physical and chemical modification, using high and new technologies to strengthen the modification, and then fully mixing with other inorganic polymer materials, it is a new type of catalytic oxidation flue gas desulfurization additive with stable structure and performance. Its main Most of the ingredients are polymer catalysts, which have strong reactivity with SO2. Since the flue gas desulfurization additive has good stability, it fully meets the requirements of the desulfurization process.
The vast majority of thermal power plants in my country use limestone wet desulfurization for desulfurization. As the country continues to improve sulfur dioxide emission standards for desulfurization units in thermal power plants, existing equipment and technology can no longer meet relevant requirements. Adding a desulfurization catalyst during the desulfurization process can greatly improve the desulfurization efficiency and make the emission concentration significantly lower than the national standard.
2. Advantages of desulfurization catalysts
1. Improve desulfurization efficiency without the need for equipment expansion and modification
Improve the gas-liquid mass transfer rate of sulfur dioxide and strengthen the control of sulfur dioxide. absorption to increase the desulfurization rate. At the gas-liquid interface, the catalyst can combine with a large number of H+ ions generated by the dissolution of SO2, allowing H+ ions to be transferred from the liquid film to the liquid phase body. The pH of the slurry will not drop too fast due to the dissolution of SO2. At the same time, the gas phase resistance is reduced, promoting SO2 absorb.
2. Energy saving and consumption reduction (saving factory electricity)
On the premise that the inlet sulfur dioxide concentration of the desulfurization device is within the design value range, first, part of the absorption tower slurry circulation can be shut down pump, which relatively reduces the liquid-gas ratio required by the system and reduces the power consumption rate of the desulfurization system, thereby effectively reducing the desulfurization operation costs and desulfurization maintenance and repair costs; secondly, it can save the energy consumption of the ball mill in the pulping system and effectively increase the coarse-grained limestone (250 mesh) ) utilization rate, basically achieving the same desulfurization efficiency as (325 mesh) particle size limestone.
3. Reduce the dosage of limestone
Increase the utilization rate of desulfurizer, thereby reducing its dosage. The catalyst can increase the solubility of limestone in the liquid phase and strengthen the dissolution of limestone. At the solid-liquid interface, the catalyst can provide an acidic environment that is conducive to the dissolution of CaCO3, reduce liquid phase resistance, and promote the dissolution of limestone.
4. Improve the flexibility of coal-fired adjustment, desulfurization operation and backup
Since the solubility of SO2 and the dissolution of solid CaCO3 are limited, the addition of desulfurization catalyst provides an alkaline base. The mass transfer factor of the liquid membrane is enhanced, which not only promotes the dissolution of CaCO3 and increases its dissociation rate, but also reduces the liquid phase resistance. The pH of the slurry will not drop too fast due to the dissolution of SO2. When using a desulfurization catalyst, the desulfurization system Can operate at a lower pH value, increasing the flexibility and stability of the main engine coal-fired adjustment and desulfurization system operations;
5. Increase the dispersion of limestone and reduce equipment scaling
The active ingredients in the catalyst can improve the surface activity of limestone, increase the dispersion of limestone, reduce its settling speed, and reduce scale and blockage of equipment.
6. Improve the oxidation efficiency, reduce the sulfite content, and improve the dehydration efficiency of the vacuum belt conveyor
The catalyst can reduce the surface tension of the limestone slurry, reduce the critical crystal nucleus radius, and strengthen HSO3 The oxidation of - makes CaSO4 and CaSO3 easy to precipitate gypsum, and CaSO4 and others are in an unsaturated state, hindering the formation of chemical hard scale. Ensure long-term operation of the equipment to prevent scaling.
7. Reduce system resistance and energy consumption
Stop operating part of the absorption tower slurry circulation pump, which will relatively reduce the liquid-gas ratio required by the system, and also reduce system resistance. Reduce energy consumption.