Low-temperature methanol washing to remove ammonia content
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This post was last edited by eddy-8280103 on 2009-5-21 08:46 The low-temperature methanol wash has high ammonia content. What are some methods to reduce it? Control of ammonia washing tower ； Is there any other way to open the ammonium bicarbonate crystallization pipeline and discharge the ammonia to the downstream section?
An external discharge pipeline is set up in the cold area of the reflux tank of the hot regeneration tower. According to the test analysis, when the ammonia content is high, a part of the methanol can be discharged to control the ammonia content in the methanol in the system. It’s just that this part of H2S-rich methanol is difficult to handle.
Ammonia is difficult to decompose when dissolved in water, and ammonia should be mainly concentrated at the bottom of the regeneration tower. Ammonia discharge should be discharged at the bottom of the regeneration tower
Set up water washing in the conversion section to ensure that the ammonia content in the low-temperature methanol washing section does not exceed the standard.
The ammonia content in the low temperature methanol scrubbing system will not be very high! Because there are treatment measures in the pre-process section, that is, changing the water washing settings of the section, the ammonia content can be greatly reduced. ； In addition, in the low-temperature methanol washing system, the ammonia content will accumulate after long-term circulation, which will increase the ammonia content and affect the absorption. When the ammonia content reaches a certain level, a certain amount of ammonia-containing methanol will be discharged, usually at the top of the regeneration tower.
There are two methods to control the ammonia content of methanol in the low-temperature methanol wash cycle.: The first is to control the source of ammonia, and control the total amount of ammonia entering the system by adjusting the shift gas scrubbing water. ； The second is to adjust the temperature of the ammonia cooler at the top of the thermal regeneration tower and control the amount of ammonia brought out of the system with the acidic gas. At the same time, if necessary, you can directly open the bypass valve of the hydrogen sulfide heat exchanger and discharge it for a period of time to reduce the ammonia content, but this will have an impact on the methanol loss.
What we do here is control the temperature of the acidic gas. Increase its temperature. Taken away with acid gas. In addition, a bypass is set up to send it directly to sulfur recovery.
I'm confused. If the ammonia content is high, what chemical reactions will occur? Can you write down the equations? . Thank you
I wonder if the ammonia content mentioned by the poster refers to the subsequent distillation part of methanol? It is still the purification part of the front stage. We know here that the ammonium bicarbonate in the purification part is high, and the methanol in the reflux part is used to solve the problem. It is similar to adding methanol before entering W003.
Friends upstairs, can you tell me the specific method? Is it the top or the bottom?
•It can react under normal temperature and pressure. When there is sufficient ammonia gas, the reaction is:: 2NH3+H2S==(NH4)2S When the ammonia gas is insufficient, the reaction is: NH3+H2S==NH4HS •If there is an excess of CO2, it is CO2+NH3+H2O=NH4HCO3. If there is an excess of NH3, it is CO2+2NH3+H2O=(NH4)2CO3 •CO2+ 2NH3 = CO(NH2)2 (urea)+H2O]