Principle and process of SXC-Ⅲ water jet desulfurization and dust removal technology

Overview of the water jet process: The SXC-III water jet desulfurization and dust removal technology is a high-pressure atomization-based method for desulfurization and dust removal. It was developed for the desulfurization of various types of boilers, with the main goal of integrating desulfurization and dust removal functions. Special attention is paid to the scientific arrangement of the high-efficiency spraying system, thereby achieving a better level of gas-liquid mixing. This setup enhances the aggregation of mist particles and the fragmentation of liquid droplets, resulting in extremely high desulfurization efficiency of 95% and dust removal efficiency of 99%. It represents a mature desulfurization and dust removal technology at the world’s advanced level. Compared to other desulfurization methods, this technology has the following advantages: ◆ No desulfurizing agents are used inside the desulfurization tower; only high-pressure atomized water is utilized for desulfurization and dust removal. The water jet unit generates ultra-fine water mist with a volume expansion of over 20,000 times. The diameter of these mist droplets can range from 1 to 15 microns, while the pressure can reach 25–30 MPa and the velocity can exceed 100–200 m/s. Full contact between the gas and liquid phases allows SO2 to react with water to form H2SO3. After forced absorption of SO2, the flue gas cools down, and due to frequent collisions, the acidic mist droplets merge and grow larger. In this way, the first stage of desulfurization takes place within the jet tube. It then enters the desulfurization tower in a tangential direction; driven by high-pressure gas, it rotates at high speed. The strong centrifugal force causes the acidic water and moisture-laden dust to move downward along the tube walls, thereby achieving the first stage of dust and water removal. Acidic, dusty waste liquids are pumped into a neutralization tower, where they undergo neutralization through thorough mixing with alkaline lime water. Due to the acidic environment inside the desulfurization tower, the cleaning effect improves with each cycle, which prevents the nozzles from getting clogged and the equipment from scaling. No maintenance is required for 10 years, and the service life can reach 20–30 years. ◆It features high desulfurization efficiency; a secondary desulfurization unit is employed. After the initial desulfurization, the flue gas rises and encounters a specially designed S-shaped filler layer, which creates a turbulent flow. A bidirectional jet spraying system is installed to ensure secondary mixing of water mist and flue gas. The turbulent flow enhances the mixing of gas and liquid, effectively capturing any remaining SO2 and NOx, thereby ensuring that the overall desulfurization efficiency of the system remains above 95%. ◆Efficient mist removal: To ensure that the flue gas is free of water, an efficient mist remover is installed above the tower; its mist removal efficiency can exceed 98%, which helps to prevent the formation of water rings and the splashing of water droplets. Furthermore, a flushing device has been designed specifically for the demister to regularly clean the dust buildup in those areas of the demister where it may accumulate over time due to continuous operation, thereby eliminating the need to shut down the furnace in order to remove this dust ； ◆It features low flue gas resistance and a safety-protection induced draft fan. Traditional desulfurization and dust removal technologies involve reverse injection of fluid into the flue gas, which requires an increase in flue gas resistance; in other words, the higher the desulfurization efficiency, the greater the pressure loss. The water jet technology equipment is installed after the induced draft fan and uses forward spraying to generate a strong negative pressure sufficient to counteract the smoke flow resistance caused by the desulfurization process. The higher the desulfurization efficiency, the lower the flue gas resistance, eliminating the need to replace the induced draft fan and thus avoiding failures associated with it. ◆Liquid and sludge are separated, achieving zero wastewater discharge; a high-vacuum concentrator thoroughly separates the liquid from the sludge, resulting in dry sludge and reclaimed water. The composition of the dry residue is mainly a mixture of dust, Ca2CO3, and other substances. This mixture consists of neutral salts and neutral oxides, and does not cause secondary pollution. The incorporation of slag and fly ash constitutes excellent raw materials for manufacturing fire-free bricks. The highly purified neutral water is directed into a recycling pool for reuse, thereby achieving zero wastewater discharge. ◆With low investment and operating costs, the water jet desulfurization and dust removal technology is highly mature. It reduces the required floor space by half compared to conventional desulfurization processes, and allows for savings of over 1/3 in both equipment costs and operating expenses, thereby helping to reduce the overall operating costs of boiler flue gas treatment systems.

Adding to what was said above: The SXC-type desulfurization dust collector is mainly composed of a swirl chamber wetting mechanism, a spraying dust collection mechanism, a self-actuating washing mechanism, a water level control mechanism, a circulating water supply system, and a waste discharge system. The dust enters the dust collector, where it undergoes three stages of dust removal: wet cyclone inertial dust removal, spray sedimentation dust removal, and impact washing. Due to its long processing time and high efficiency in dust and sulfur removal, the removed dust is discharged together with wastewater through the waste outlet into the circulation tank. Once the water becomes clear, it is reused via a pump. The purified flue gas, after gas-water separation, is released through the exhaust outlet into the chimney. Performance indicators: Dust emission concentration (mg/m3), Ringelmann blackness scale, Dust removal efficiency (%), Desulfurization efficiency (%), Energy savings efficiency (%), Pressure drop (Pa), Air handling volume (m3/h): 96 > 50 > 850 > 850 > 850 > 850 > 850 > 8