Chinese
Water gas and natural gas both contain a certain amount of sulfides. These substances not only pollute the environment but also cause severe corrosion to production equipment and facilities. Therefore, gas desulfurization is an essential step in the production, transmission, and distribution of gas. Gas desulfurization can be carried out using either dry or wet methods. The dry process is simple and provides a high purification level, but the equipment is bulky, resistance is high, and the desulfurizing agents must be replaced frequently, making it suitable only for smaller gas processing capacities. In wet desulfurization processes using catalysts such as ××, hydrogen sulfide in the gas is absorbed by the desulfurization solution in the desulfurization tower, forming hydrosulfide compounds. These compounds are then oxidized by catalysts in pipelines and reaction tanks to produce elemental sulfur. In the regeneration tower or regeneration tank, the catalyst is oxidized and regenerated, while elemental sulfur forms sulfur foam with the desulfurization solution, which is then sent to the sulfur recovery system.
(1) The process flow of the sulfur melting kettle method is as follows:
The sulfur foam liquid enters the sulfur foam tank and is heated to about 90°C to promote the growth of sulfur particles and achieve preliminary separation. The clear liquid is returned to the solution circulation system. The concentrated sulfur foam is then fed into a vacuum filter to form sulfur paste. The sulfur paste is sent to the sulfur melting kettle and heated by a steam jacket to 130–140°C. The molten sulfur is discharged into a cooling tank, naturally cooled, then crushed and packaged. This process is relatively mature and widely used in domestic coking plants and gas plants.
(2) The process flow of the rubber belt vacuum filter for desulfurization is as follows:
Sulfur foam enters the intermediate sulfur foam tank and is pumped directly into the filter press. After filtration by the desulfurization vacuum filter, the solution permeates through the filter cloth and returns to the circulating solution system, while sulfur is retained on the surface of the filter cloth and forms sulfur paste. Through scraping and back-blowing, the sulfur paste is removed and discharged. The main advantages of this method are its simple process, convenient operation, and low maintenance rate, with the filter cloth typically replaced every 2–3 months. The separated filtrate contains about 8% suspended sulfur, resulting in a relatively low sulfur recovery rate. Another disadvantage is that the sulfur paste produced by the vacuum filter contains a high moisture content of about 32%, and its high viscosity makes packaging inconvenient. Nevertheless, replacing the centrifuge process (foam tank—centrifuge—sulfur paste) with the vacuum filtration process (foam tank—vacuum filter—sulfur paste) has achieved considerable economic benefits. The main advantages include saving a large amount of steam, reducing power consumption and maintenance costs, and achieving more stable production than before.
