What is the purpose of washing with lean amine at the top of the rich amine flash tank in the amine solution regeneration unit?

This post was last edited by ylb913 on 2015-12-31 08:26. 1. It is intended to absorb hydrogen sulfide from the vapor. 2. Is there a pump at the bottom of the flash tank? Otherwise, the pressure control cannot be very low. 3. The temperature of the flash vapor line is very low, much lower than that of the amine solution; care must be taken to separate the liquids. 4. Amine liquid is not fed at the top of the flash vapor, or only a very small amount of amine liquid is supplied; as a result, the hydrogen sulfide concentration after absorption is very high (tens of thousands), and this is a common phenomenon for us. ——Our flash vapor is sent to the low-pressure gas pipeline network for recovery. But theoretically, the material requirements for pipelines that absorb hydrogen sulfide versus those that do not are different, including whether heat treatment is necessary. 4. I have only heard an introduction to the process of producing acid using acidic gases; in such a case, I think it is acceptable not to absorb the flash vapor.

1. It is to absorb hydrogen sulfide from the flash vapor. Generally, there are also requirements regarding the light hydrocarbon content in the acidic gases used for sulfur production, right? 2. Is there a pump at the bottom of the flash tank? Otherwise, the pressure control cannot be very low. I just need to ensure that the acidic gas generated by flashing can be sent to the acid production unit. At most, the power and head of the pump at the bottom of the amine-rich liquid flashing tank will need to be increased. 3. The temperature of the flashing gas pipeline is very low, much lower than that of the amine liquid; care must be taken regarding liquid separation. Isn’t the operating temperature of the rich amine flash tank usually around 70ºC? What is the temperature of the flashed gas? 4. When no amine liquid is added to the top of the flashed gas, or when only a very small amount of amine liquid is used, the hydrogen sulfide content after absorption becomes very high (tens of thousands). This is a common phenomenon for us. ——Our flash vapor is sent to the low-pressure gas pipeline network for recovery. But theoretically, the material requirements for pipelines that absorb hydrogen sulfide versus those that do not are different, including whether heat treatment is necessary. Mainly, it is this tube that is a bit more expensive, but it is also thinner. And in our case, we ended up combining the lines at the top of the reflux tank with those within the unit to send the material to the sulfur recovery unit for acid production; so in that sense, there isn’t much difference. 4. I’ve only heard an introduction to the process of producing acid using acidic gases, and I think it’s acceptable not to absorb the flash vapor in such cases. I found the flowchart I drew to be satisfactory in every way; I didn’t notice this problem. It was only when the manager came to help review the PID that I realized this issue – I had indeed been negligent before. .

The acid production process involves the reaction that produces sulfur dioxide, and the required furnace temperature is relatively low, at 1010 degrees? For most desulfurized gas streams, cooling is achieved by using a large amount of excess air; it is also normal for fuel gases with low concentrations to be used in combustion. The temperature of the flash vapor line is cool to the touch throughout the year; it is normal for there to be a drop in temperature during the flashing process, especially when it contains liquefied gas components. In the acidic gases in our workshop, the hydrocarbons are mainly of the C3 type. Only liquid ammonia enriched with liquefied gas can result in the vaporization of a larger amount of gas. Over the past few years, as the proportion of ammonia solution used for gas desulfurization (including various dry gases and sulfur exhaust gases, without liquefied gas) in the regenerated ammonia solution has increased, it has become more difficult to maintain pressure in the flash tank. What we do is to use artificial pressure injection to keep the pressure at 3.5 kg/cm2, while the ammonia solution exits under its own pressure. Since there is a separate amine solution regeneration system dedicated to the sulfur unit, we simply do not need a flash tank.

I’ve learned so much; I really enjoy this kind of knowledge

Yes, the flash tank is primarily used to remove gaseous hydrocarbons and light oils from the rich liquid. If the gas from the upper part is used directly for acid production, the pressure can be reduced, which facilitates better flashing of the gas