Reviewing the Old to Discover the New (Series 12)

There are many conditions in the desulfurization absorption process and the oxidation regeneration process that are both contradictory and interrelated; therefore, both aspects must be taken into account. The oxidation regeneration is a crucial part of the desulfurization process, as it directly determines the efficiency of desulfurization as well as the control of the resistance in the desulfurization tower. The liquid level in the regeneration tank must be controlled steadily to prevent large fluctuations and splashing; it is also necessary to ensure that the flotation foam overflows evenly without accumulating. For the injectors in use to be evenly distributed and to function properly, it is necessary to regularly check the nozzles and throats based on the amount of air drawn in by suction or any backflow, to determine whether there is any blockage or buildup, as well as to assess the concentricity of the injectors; otherwise, appropriate actions should be taken or the injectors should be replaced. The self-priming air volume should be determined based on the level of H2S removed during desulfurization and the production load, and it is adjusted by using an appropriate regeneration pressure as well as the opening degree of the air intake valve. When all the air valves are opened, the amount of regenerating air increases, resulting in a higher blowing intensity that facilitates the oxidative regeneration of the solution and more thorough CO2 stripping. However, if too much air is used, the sulfur foam layer becomes unstable, sulfur flotation separation deteriorates, and high levels of suspended sulfur are produced. If the air volume remains too high for an extended period, the solution potential will be high, which will accelerate side reactions. To a certain extent, the amount of recycled air should increase or decrease in accordance with the production load; when making adjustments, only the air intake valve should be used, and the solution valve should not be closed. The actual air intake amount is generally should be 12–15 times the theoretical air amount

The rich liquid emerges from the bottom of the desulfurization tower and enters the rich liquid tank. After being pressurized by the regeneration pump, it forms a jet as it passes through the injector nozzles, creating a local negative pressure that automatically draws in air. At this point, the gas-liquid two-phase mixture is evenly distributed at high speeds and is in a highly turbulent state; after undergoing enhanced reaction in the contraction zone, throat, diffusion tube, and tail pipe, it enters the regeneration tank for oxidative regeneration. Flotation of elemental sulfur is carried out through uniform upward movement distributed by a perforated plate distributor. Under the action of air, they collide with each other more frequently, forming small sulfur clusters; these clusters gather to form a foam layer that rises with the air and flows into the foam tank, from where it is sent to the sulfur melting station. The clear liquid then enters the clear liquid ring groove and, via a level regulator, goes to the lean liquid tank. At the same time, under the aeration effect of air, waste gases such as CO2 in the rich solution can be driven out, which reduces the suspended sulfur in the solution and increases its alkalinity, thereby enabling the various components to be adjusted and restored. As well as the oxygen absorption regeneration of the catalyst to restore its activity, thereby improving the quality of the solution and reducing the residual sulfur content.

In the desulfurization system, the desulfurization liquid passes at high speed through the nozzle of the injector to form a jet; this jet creates a local negative pressure that draws in air. As a result, the two-phase fluid is immediately dispersed at high speeds, leading to a state of high turbulence. This increases the gas-liquid contact area, allowing the desulfurization liquid to be rapidly and effectively regenerated and oxidized. The sulfur particles formed are then floated out in the regeneration tank, thereby completing the transformation of the desulfurization liquid from a rich liquid to a lean liquid.

The rich liquid exits from the bottom of the desulfurization tower and enters the rich liquid tank. After being pressurized by a regeneration pump, it forms a jet as it passes through the injector nozzles, creating a local vacuum that automatically draws in air. At this point, the gas-liquid two phases are evenly distributed at high speeds and are in a highly turbulent state; after undergoing enhanced reaction in the contraction zone, throat, diffusion tube, and tail pipe, they enter the regeneration tank for oxidative regeneration. Elemental sulfur flotation is carried out through uniform upward dispersion via a perforated plate distributor. That is, under the action of air, they collide with each other, forming small sulfur clusters; these clusters gather to form a foam layer that rises with the air and flows into the foam tank, from where it is sent to the sulfur melting station. The clear liquid then enters the clear liquid ring groove and, via a level regulator, goes to the lean liquid tank. At the same time, under the aeration effect of air, waste gases such as CO2 in the rich solution can be driven out, which reduces the suspended sulfur in the solution and increases its alkalinity, thereby enabling the various components to be adjusted and restored. As well as the oxygen absorption regeneration of the catalyst to restore its activity, thereby improving the quality of the solution and reducing the residual sulfur content. Therefore, the liquid phase pressure of the injector, the amount of air, the blowing intensity, the reaction temperature, the residence time, the control of the foam layer, and overflow are all very important. Moreover, the requirements for process equipment in absorption and regeneration involve inconsistent control criteria (some of which are even opposite to each other), and it is necessary to find a balanced state. Therefore, the quality of the lean liquid after oxidation regeneration directly determines the desulfurization efficiency and its impact on the resistance in the desulfurization tower.

How does a jet regeneration tank work? The rich liquid exits from the bottom of the desulfurization tower and enters the rich liquid tank. After being pressurized by a regeneration pump, it forms a jet as it passes through the injector nozzles, creating a local vacuum that automatically draws in air. At this point, the gas-liquid two phases are evenly distributed at high speeds and are in a highly turbulent state; after undergoing enhanced reaction in the contraction zone, throat, diffusion tube, and tail pipe, they enter the regeneration tank for oxidative regeneration. Elemental sulfur flotation is carried out through uniform upward dispersion via a perforated plate distributor. That is, under the action of air, they collide with each other, forming small sulfur clusters; these clusters gather to form a foam layer that rises with the air and flows into the foam tank, from where it is sent to the sulfur melting station. The clear liquid then enters the clear liquid ring groove and, via a level regulator, goes to the lean liquid tank. At the same time, under the aeration effect of air, waste gases such as CO2 in the rich solution can be driven out, which reduces the suspended sulfur in the solution and increases its alkalinity, thereby enabling the various components to be adjusted and restored. As well as the oxygen absorption regeneration of the catalyst to restore its activity, thereby improving the quality of the solution and reducing the residual sulfur content. Therefore, the liquid phase pressure of the injector, the amount of air, the blowing intensity, the reaction temperature, the residence time, the control of the foam layer, and overflow are all very important. Moreover, the requirements for process equipment in absorption and regeneration involve inconsistent control criteria (some of which are even opposite to each other), and it is necessary to find a balanced state. Therefore, the quality of the lean liquid after oxidation regeneration directly determines the desulfurization efficiency and its impact on the resistance in the desulfurization tower.

Working principle of the desulfurization injector in the regeneration tank: The rich liquid exits from the bottom of the desulfurization tower and enters the rich liquid tank. After being pressurized by the regeneration pump, it passes through the injector nozzle to form a jet, creating a local negative pressure that automatically draws in air. At this point, the gas-liquid two phases are evenly distributed at high speeds and are in a highly turbulent state; after undergoing enhanced reaction in the contraction zone, throat, diffusion tube, and tail pipe, they enter the regeneration tank for oxidative regeneration. Elemental sulfur flotation is carried out through uniform upward dispersion via a perforated plate distributor. That is, under the action of air, they collide with each other, forming small sulfur clusters; these clusters gather to form a foam layer that rises with the air and flows into the foam tank, from where it is sent to the sulfur melting station. The clear liquid then enters the clear liquid ring groove and, via a level regulator, goes to the lean liquid tank. At the same time, under the aeration effect of air, waste gases such as CO2 in the rich solution can be driven out, which reduces the suspended sulfur in the solution and increases its alkalinity, thereby enabling the various components to be adjusted and restored.