Liquid presence in the hydrogen dry gas compressor room
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The hydrogen production dry gas compressor unit has severe liquid contamination (about 1% ethanolamine, with the rest being water). Liquid is removed every two hours on average; after each removal, the liquid level in the unit’s tank rises rapidly. Once it reaches over 20%, the rate of increase slows down. Currently, liquid is being removed from the tank when its level is above 30%. The dry gas used for hydrogen production comes from catalytic processes and coking processes. May I ask the experts what is causing this issue?
Check whether the tube bundle of the inter-stage cooler is perforated; based on your description, the possibility of perforation is quite high
After the compressor boosts the pressure, the liquid level in the inter-stage buffer tank may consist of heavy hydrocarbons; when the discharge is increased, these substances vaporize instantly, causing the liquid level to drop. Once the discharge is stopped, the liquid level rises rapidly again within a short time.
What is 20% of the inter-stage tank? With such severe liquid carryover, is there nothing abnormal with the compressor? What is the pressure between compressor stages? The possibility of leakage in the inter-stage water cooler is likely low ； Was the composition analysis of the feed gas done? It seems that the analysis on the third floor is quite reasonable ； The liquid in the inter-stage tank either leaks in from the unit or is carried in by the raw material; by eliminating each possibility one will surely be able to find the cause.
Based on the owner’s description, it’s impossible that the raw material contains water; if the raw material did contain water, then it would be the compressor inlet buffer tank that would have liquid in it first, and not just the inter-stage liquid separation tanks； Secondly, if the raw material contained water, the ethanolamine content in the condensate could not be so low. As mentioned by the original poster, 1% is ethanolamine and the rest is water; therefore, it is not a problem related to light or heavy hydrocarbons. Although the pressure of the feed gas is higher than that of the circulating water, it should logically be the feed gas that penetrates into the circulating water. However, in the event of perforations in the heat exchanger tubes, it is also possible for water to penetrate into the feed gas; we have experienced situations where circulating water entered the buffer tank at the second-stage outlet of the fresh hydrogen compressor.
The unit is currently equipped with two sets of compression units. Both sets suffer from severe liquid accumulation in the tanks within the units, with very little liquid in the inlet tanks. Unit A is in a worse condition than Unit B; Unit A requires liquid removal every about two hours, while Unit B needs it done about two to three times every eight hours. The problem of liquid accumulation persists for long periods, and it becomes more severe in winter. The temperature at the primary inlet tank is 32°C with a pressure of 0.21 MPa, while at the primary outlet it is 109°C with a pressure of 0.775 MPa. At the secondary inlet, the temperature is 27.4°C with a pressure of 0.759 MPa
Does the liquid level in the interstage buffer tank rise when the compressor starts up?
If the pressure ratio of the primary exhaust gas is higher than that of the circulating water, it rules out an increase in the liquid level in the inter-stage separator as the cause of leakage within the tubes of the inter-stage cooler. We have a capacity of 2,000 cubic feet per hour; the inter-stage separator produces 20 liters of amine solution per shift over an 8-hour period