Regarding whether condensed liquid at high pressure in circulating hydrogen can cause liquid slugging problems
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This post was last edited by sdwfsgyykai on 2018-5-18 at 14:09. The hydroisomerization unit uses hydrocracking tail oil as its feedstock; the working medium in the reciprocating compressors is recycled hydrogen, with an inlet pressure of 15 MPa and an outlet pressure of 16 MPa. The inlet temperature of the recycled hydrogen is below 50°C, usually around 45°C, while the temperature of the soft water used in the cylinders ranges from 41 to 46°C. Mild liquid slugging sometimes occurs during the operation of the unit. Question: Is liquid slugging caused by the excessively low temperature of the cooling medium, which leads to the condensation of certain components in the circulating hydrogen under high pressure? What are the main components of condensate? How to avoid it? Let’s discuss it together.
Check whether the light oil and recycled hydrogen effluents are normal; also verify if it’s lubricating oil
Due to its large volume and complex composition, recycled hydrogen is generally processed using turbines.
This is most noticeable during each shutdown; lighter-density oil is released from the pipes and inside the machine, and it evaporates quickly when applied to the hands. Its composition is similar to that of C4. If not removed in time, it can cause liquid slugging in the compressor. The temperature in the liquid separation tank at the inlet of the circulating hydrogen compressor is generally kept below 40°C, allowing for thorough gas-liquid separation in the buffer tank and preventing liquid from entering the compressor； The upper part of the circulating hydrogen demister tank is equipped with a defoaming mesh that serves to remove condensate ； Drainage of inlet pipes and compressor surge tank drain lines before startup ； Regularly drain the fluid from the inlet and outlet buffer tanks of the compressor that is in operation ；
If the process requirement is very low, choosing a turbine from an economic perspective is not viable.
API 618 requires that the cylinder cooling system provided shall prevent gas condensation. The coolant inlet temperature should be at least 5K (10°F) higher than the inlet gas temperature.