A fiber liquid film contactor amine washing desulphurization device and an amine washing desulphurization method

Abstract

The invention discloses a fiber liquid film contactor amine washing desulphurization device. The device comprises a first fiber liquid film mass-transfer contactor subassembly. The first fiber liquid film mass-transfer contactor subassembly comprises a fiber liquid film contactor, a settlement separating tank and a stream dividing pack. The vertical fiber liquid film contactor is mounted on one end of the horizontally disposed settlement separating tank through a flange. The device is advantageous in that when the hydrogen sulfide content of liquefied gas produced by an oil refinery is lower than 5000 mg / m3, the hydrogen sulfide content of the liquefied gas hydrogen sulfide in which is removed can be ensured to be lower than 1 mg / m3 by adopting amine washing with a primary fiber liquid film contactor and amine removing with a coalescer, and the liquefied gas after removal is free of entrainment of free amine liquids.

Description

Technical field [0001] The present invention relates to a device for removing hydrogen sulfide from light hydrocarbon products produced in an oil refining unit, particularly a method for removing sulfur from dry gas or liquefied gas, specifically a device for amine sulfur washing of a fiber liquid membrane contactor and an amine sulfur removal device. Sulfur removal method. Background technique [0002] Hydrogen sulfide is a highly toxic and corrosive substance, so light hydrocarbon products such as dry gas and liquefied gas produced during the production process of oil refineries must be completely desulfurized before being used as products. [0003] At present, refineries mostly use absorption towers for dry gas, liquefied gas and other light hydrocarbon products to remove hydrogen sulfide. Amine washing absorption towers are generally sieve plate towers or packed towers, and the most commonly used absorption solution is N-methyl. Diethanolamine (MDEA), the absorption tem...

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Problems solved by technology

[0003] At present, for light hydrocarbon products such as dry gas and liquefied gas, refineries mostly use the absorption tower to elute hydrogen sulfide; the amine washing absorption tower is generally a sieve plate tower or a packed tower, and the most used absorption solution is N-methyl Diethanolamine (MDEA), the absorption temperature is generally 30-45°C, the concentration of amine solution used by most domestic refineries is 25-30%, and the concentration of amine solution used in developed countries is mostly 30-45%, and the highest can reach 50% ;The higher the concentration of the amine solution, the better the absorption capacity for hydrogen sulfide; but due to the influence of the mass transfer mode of the absorption tower, the higher the concentration of the amine solution and the longer the service life of the amine solution, the easier it is to cause light hydrocarbons to foam and entrain the amine solution; After the light hydrocarbon entrains the amine liquid, the hydrogen sulfide index is easily unqualified, and at the same time, the loss of the amine liquid increases. It is necessary to regularly replenish the same amount of fresh amine liquid as the running loss, which increases the cost of light hydrocarbon sulfur; the amine liquid after absorbing hydrogen sulfide It is called rich amine solution. When 30% concentration amine solution is used in China, the hydrogen sulfide content in rich amine solution is generally in the range of 10-20g / L, while the theoretical sulfur capacity of 30% concentration amine solution can reach up to 50g / L. The reason why the actual sulfur capacity is much lower than the theoretical sulfur capacity is that, on the one hand, it is related to the low mass transfer efficiency of the absorption tower, and on the other hand, it is related to the quality of the amine liquid and its effective MDEA content, heat-stable salt and other harmful impurities. The rich amine liquid after absorbing hydrogen sulfide is heated to 120-125°C by a reboiler, the hydrogen sulfide and the amine liquid are analyzed and separated, the hydrogen sulfide goes to the recovery device, and the amine liquid returns to the absorption unit for recycling after cooling; therefore, the rich amine The higher the hydrogen sulfide content in the liquid, the smaller the amine liquid circulation flow required for sulfur, and the less energy consumption for amine liquid regeneration

[0004] Chinese patent 200710164582.7 discloses an amine liquid desulfurization method and a special device with a high hydrogen sulfide removal rate; this patent only improves the amine liquid regeneration tower unit to reduce the steam consumption of the reboiler, but does not use the amine liquid The hydrogen sulfide absorption mass transfer equipment started, and the circulating flow rate of the amine liquid remained unchanged

[0005] Chinese patent 2012102616574 discloses a device and method for removing hydrogen sulfide from liquefied petroleum gas; this patent uses a liquid film absorption tower instead of a conventional packed tower, and a liquid film absorption tower is connected in series with an amine liquid settling tank and a polymer knot; the patent only illustrates the experimental effect of sulfur in liquefied petroleum gas, and does not mention the sulfur effect in other light hydrocarbons such as dry gas; and the hydrogen sulfide content in liquefied petroleum gas is only 12000mg / m3 3 , the hydrogen sulfide content after removal is less than 10mg / m 3 , and with the high sulfidation of crude oil, the hydrogen sulfide content in liquefied petroleum gas in industrial plants exceeds 50000mg / m 3 There are more and more working conditions, and the hydrogen sulfide content should be as low as possible after desorption; after the liquid film absorption tower, the settling tank and coalescer are connected in series at the same time, which shows that the liquid film absorption tower still has serious amine liquid entrainment, and the liquid There is still a lot of room for improvement in the structure of the membrane absorption tower

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