What to do if the oil temperature in the expansion tank of a heat transfer oil furnace is high?
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Recently, oil and gas have been escaping from the air vent of the expansion tank in our unit’s gas-fired heat transfer oil furnace. When I went up to the platform of the expansion tank (at a height of about 10 meters), I found that the oil level in the expansion tank was higher than before, and the temperature of the oil there was also very high; previously, the oil in the expansion tank was at room temperature. I checked the flow system of the heat transfer oil furnace and found no problems (the valve settings were the same as before). Additionally, the reboiler at the bottom of the tower, which uses heat transfer oil as a heating medium, has not been able to reach the required temperature (the heating temperature does not reach the process specifications). We have yet to identify the cause of this problem. I hope experts can provide some guidance. Thank you! :handshake
Possible reasons: 1. Water or light components in the oil; 2. Oil and gas separation in the return oil stream, with the liquid seal not functioning properly
1. Water vapor has entered the oil system. Inspect all equipment through which oil flows; if steam heating is used, check for leaks in the heating furnace. The pressure in the steam system is higher than that in the oil system. If it leaks, water vapor enters the oil system. Including the cooling water on the pump, in short, everything needs to be eliminated one by one. 2. It is necessary to determine whether the heat transfer oil is currently in its intended stage of use. If it has been in use for only a short time, it may not have been fully dehydrated; if it has been in use for a long time, then it is necessary to check the quality of the heat transfer oil to see if it has deteriorated or if there are signs of cracking or oxidation. If there is too much light component, the phenomenon you mentioned will also occur. 3. Use a pH test strip to check the acidity and alkalinity of the heat transfer oil, to determine whether there are any leaks in pipes or equipment that could cause materials to enter the oil system.
Heat transfer oil is the heating medium; it flows through the tube side, and the materials that exchange heat with it are light hydrocarbons, free of water； The heat transfer oil has been in use for over six years; during that time, only the heat transfer oil has been replenished, and it has never been replaced.
It is recommended to analyze the viscosity, acid value, residue, etc. of the oil product
It is recommended to check the exhaust system of the heat transfer oil, especially those related to the area around the reboiler at the bottom of the tower.
1. Water vapor has entered the oil system. Inspect all equipment through which oil flows; if steam heating is used, check for leaks in the heating furnace. The pressure in the steam system is higher than that in the oil system. If it leaks, water vapor enters the oil system. Including the cooling water on the pump, in short, everything needs to be eliminated one by one. 2. It is necessary to determine whether the heat transfer oil is currently in its intended stage of use. If it has been in use for only a short time, it may not have been fully dehydrated; if it has been in use for a long time, then it is necessary to check the quality of the heat transfer oil to see if it has deteriorated or if there are signs of cracking or oxidation. If there is too much light component, the phenomenon you mentioned will also occur. 3. Use a pH test strip to check the acidity and alkalinity of the heat transfer oil, to determine whether there are any leaks in pipes or equipment that could cause materials to enter the oil system. The answer is very detailed
This situation is likely caused by the fresh heat transfer oil added to the system containing light components and moisture. By lowering the furnace temperature to the \"oil boiling\" temperature until the light components and moisture are removed from the system, normal operation will be restored.
The thermal expansion and contraction properties of heat transfer oil cause temperature changes, which in turn lead to variations in liquid level. Doesn’t the reboiler at the bottom of the tower have any mechanism to control the amount of hot oil? Check if there’s any volume after the reboiler Can the hot oil circulate through?
If everything else is fine, it’s likely that the reboiler is scaled, resulting in low heat transfer efficiency