The return temperature of the heat transfer oil will drop suddenly
Thread Content
The return oil temperature of the company’s heat transfer oil system occasionally drops suddenly by 5–7 degrees; the heat transfer oil valves in the heating workshop show no movement or only a slight movement (the minimum valve movement value is 0.25%, with pipeline diameter of DN250). The temperature of the oil exiting the system is around 284 degrees, while the temperature of the oil returning to the system generally remains around 267 degrees; it can drop suddenly (by 5-7 degrees within one to two minutes). Checks of the thermocouples used to monitor the returning oil showed no issues. There are approximately 100 tons of heat transfer oil in the system, and it takes about 20 minutes for the entire amount to complete one cycle. I would like to ask what could be causing this situation! ! !
It would be best to also mention what substance is being heated, so that the issue can be analyzed
It is usually caused by an increase in heat. 【Material just added, reflux established】
The boiler uses biomass with a calorific value of 3800 to 4200 cal/g
In the hot workshop, there is almost no movement or adjustment. The return temperature of the heat transfer oil will drop suddenly
In a thermal equipment system equipped with a reflux mechanism, the phase before reflux is one of temperature increase; once the reflux temperature is reached, reflux occurs. The reflux flow within the system is a cold flow that helps to cool the material inside the tank, thereby improving the heat exchange efficiency, and as a result the temperature of the returning fluid drops slightly. Even if the heat transfer oil valve does not move, it can still cause fluctuations in the return oil temperature.
This shouldn’t happen; the heat transfer oil system has been in use for a long time, and this problem only appeared recently.
It seems that our production unit doesn’t have a heat transfer oil return system; I’ll go and check. Thank you
Under normal circumstances, such abnormal situations do not occur. I think it’s quite likely that there is gas in the heat transfer oil pipeline. During operation at high temperatures, the heat transfer oil in the system can undergo cracking. Generally, venting is required after several days of continuous operation, and it is also necessary to perform venting when the system is restarted after being shut down. You can pay attention to this issue. In addition, I hold a patent for an energy-efficient heat transfer oil heating system, which I hope can make your heat transfer oil heating system more energy-efficient and advanced. Does your heat transfer oil heating equipment require hot/cold switching? In systems that use heat transfer oil for heating or cooling, an important factor affecting thermal efficiency and economic costs is the switching between hot and cold oil during the process of temperature adjustment. When hot oil (or cold oil) is switched to cold oil (or hot oil), the hot oil (or cold oil) remaining in the jacket (or coils, semi-coils) of the reaction vessel is transferred to the cold oil (or hot oil) system, where it must be cooled (or heated) to become cold oil (or hot oil). Each switch causes significant heat loss and cold loss. It is estimated that, for a reactor jacket with a volume of 5 m3, the heat loss and cold loss associated with each switchover are each around 60,000 kcal (equivalent to 70 kWh), which is undoubtedly a significant amount of loss. Of course, the specific amount depends on the volume of heat transfer oil in the jacket. How can we avoid this energy loss caused by the need to cool hot oil and then reheat cold oil? Creative ideas, excellent designs, and **patents enable you to solve problems effortlessly, significantly reduce energy losses, and effectively cut production costs. Whether heat transfer oil is used for cooling or not, whether it’s the renovation of an existing system or the design of a new one, everything is so simple and easy. Low investment, high returns – why not give it a try? Guided by theory and based on practice, this patented technology has been implemented in large-scale projects. Welcome to visit! System design plans, control programs, and operating procedures can be provided.
The problem has been identified; it’s an issue with boiler operation. The oil inlet and outlet pipelines of the heat transfer oil furnace are equipped with bypass lines, primarily to ensure that the temperature difference between the incoming and outgoing oil remains around 20 degrees. At first, we simply checked whether the workshop had suddenly changed the amount of heat transfer oil used, which could have caused a drop in the return oil temperature. Subsequent investigations found that if the oil outlet temperature drops due to improper boiler operation, this will also cause the oil return temperature to drop (due to the existence of the oil inlet and outlet pipelines). This is also confirmed by examining the temperature trend of the heat transfer oil: the outlet oil temperature drops first, and after 1–1.5 minutes, the return oil temperature begins to drop as well.