Problem of unstable pressure in heat transfer oil for methanol-to-hydrogen production
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Hello, netizens! In our company, the pressure of the heat transfer oil used in methanol-to-hydrogen production experiences large fluctuations, and there is moisture in the heat transfer oil system (the oil has been replaced and dehydrated). After shutting down the system, it was found that there were sand holes in the tubes of the vaporization superheater; these issues have been resolved through welding and pressure testing, and everything is now normal. (After suppressing the vaporization superheater and the heat transfer oil heater), the pipeline network pressure remains around 3 kilograms and declines slowly. The outlet pressure of the heat transfer oil pump fluctuates greatly. What could be the reason? Thank you all!
I don’t understand; the exit temperature, exit flow rate, and so on are not clearly specified.
There’s not much change in the outlet temperature; it’s mainly the pressure fluctuations that are significant
Large fluctuations in the outlet pressure of the heat transfer oil are commonly caused by moisture present in the oil system. The source of this moisture can be incomplete dehydration during startup, new oil added to the system, contamination brought in during maintenance of the oil pipes, or blocked exhaust pipes on those oil pipes. Less common causes include internal leaks in the heat transfer equipment using thermal oil (such as reactors, superheaters, vaporizers, etc.), as well as pump failures or problems with pressure gauges.
The presence of sand in the oil tubes of the vaporization superheater indicates that the methanol-water mixture (on the high-pressure side) has penetrated into the heat transfer oil system (on the low-pressure side); it’s even possible that the heat transfer oil has made its way into the conversion system as well. The oil should be re-poured after the equipment is repaired. Also, it’s best to conduct a test to check whether the oil quality meets the requirements. Unstable pressure is usually caused by the vaporization of moisture or light components. Also, if the high-level tank does not have a nitrogen seal, it is recommended to close the auxiliary exhaust valve when the oil temperature exceeds 170°C; otherwise, the heat transfer oil will oxidize and deteriorate.
Unstable outlet pressure of the hot oil pump is either due to water in the medium or a clogged inlet filter.
The heat transfer oil has been boiled, and the inlet filter was removed – nothing blocking it was found!
Do you carry out the oil boiling operation by yourselves, or are factory technicians there to guide you? Be sure to vent the dead corners around the converter as well when heating the oil. Also, there is an exhaust vent on the pump body that needs to be vented as well. If improper oil heating is ruled out, it is likely that the heat transfer oil has deteriorated and needs to be replaced. It is recommended to take samples for testing first, and make a decision based on the analysis results.
I hope the original poster can respond to let me know if the problem has been solved.
It hasn’t been resolved yet; the heat transfer oil heater is under pressure testing!