Thermal oil regeneration

Yes, for synthetic heat transfer oil, online regeneration without shutting down the system is possible. My WeChat is 18678810180; if you’re interested, we can communicate together.

The regeneration of heat transfer oil is divided into two types: 1) on-line regeneration (which can be carried out without shutting down the furnace or stopping production), and 2) off-line regeneration. Heat transfer oil regeneration is very cost-effective for customers who use large quantities of this oil. (TEL: 1811 8269 273) It is possible to purify heat transfer oil that does not meet the standards through physical methods, such as vacuum distillation, which removes the heavier components from the oil; thus, the regenerated oil can reach standards similar to those of new oil. Additionally, online regeneration eliminates the costs associated with cleaning the boiler system, ultimately helping enterprises save a considerable amount of money

Heat transfer oil regeneration is carried out through vacuum distillation, which is very cost-effective for customers with large-scale systems.

The online regeneration technology using heat transfer oil is a new green, environmentally friendly, and energy-saving technology. This technology was developed because we successfully solved the problem of coking in new heat transfer oils, creating heat transfer oils with exceptional resistance to coking; on this basis, we were able to achieve online regeneration of existing heat transfer oils. The heat transfer oil heating technology was introduced to China from Europe and the United States just over 30 years ago, and it has been widely used for only a little more than 10 years. Regarding the testing methods for the performance of new heat transfer oils, most of them simply adopt European and American standards. China’s standard for heat transfer fluids, **GB23971-2009**, has been in effect for only about four years now; there are indeed many aspects that warrant discussion and revision. The widespread problem of coking in heat transfer oils in our country is, in terms of the quality of these oils, due to the fact that new heat transfer oils do not possess good anti-coking properties. However, the testing methods for evaluating the most important performance characteristic of heat transfer oils – namely their anti-coking ability – are not specified at all in the relevant standards. The thermal stability of heat transfer oils according to GB23800 (under nitrogen protection) and their thermal oxidation stability at 175°C for 72 hours cannot fully replace measures of their anti-coking ability and overall stability when exposed to both high temperatures (280°C–330°C) and oxidation (120°C–175°C). The flash point of a large number of severely coked, discarded heat transfer oils shows almost no significant change compared to that of new oil. This indicates that the heat transfer oil did not undergo any decomposition and was not used at temperatures exceeding its limits. It also demonstrates that the thermal stability of such oils under nitrogen protection simply cannot replace their anti-coking properties and overall stability under conditions involving both heat and oxidation; otherwise, new heat transfer oil would readily coke in an open system. This conclusion was drawn after testing thermal oil from well-known domestic and international brands. The currently popular \"criteria\" for determining whether heat transfer oil can continue to be used, based on reference viscosity, flash point, acid value, and changes in residue, cannot fully and accurately assess the coking condition of the heat transfer oil. The purpose of testing the physical and chemical properties of new heat transfer oils as well as conducting bench simulation tests is to ensure their most important performance characteristics in use. However, the widespread occurrence of coking in heat transfer oils currently in use demonstrates that the GB23971** standard is incomplete and unreasonable. Moreover, there seems to be no distinct connection between the commonly used \"criteria\" for determining when heat transfer oil is no longer usable, and the measures taken to prevent the oil from coking or forming sludge. However, for the vast majority of heat transfer oils currently available on the market that are not of this type, an increase in residue and acid value, as well as changes in viscosity and flash point, can indeed be used to determine the coking condition of the heat transfer oil. However, in a heat transfer oil formulation developed under stringent test conditions that exceed **standard requirements, the increase in residue and acid value is not closely related to coking of the heat transfer oil. This represents a major breakthrough in understanding. Only by clarifying these issues can we achieve the online regeneration of heat transfer oil. There are two types of working systems that use organic heat carriers for heat exchange, namely open heat exchange systems with heat transfer oil and closed heat exchange systems. A heat exchange system in which the exhaust pipe of the expansion tank is directly connected to the external air is called an open-type heat transfer system ； A heat transfer system in which the expansion tank is isolated from air is called a closed-loop heat exchange system. Here is a brief introduction to the respective advantages of use and the operating characteristics of the two heat exchange systems. In an open-type heat exchange system that uses thermal oil as the medium, the exhaust pipe of the expansion tank is connected directly to the atmosphere; no additional equipment is required, making the process system relatively simple and easy to operate. Currently, open heat exchange systems are used for heat exchange involving thermal oils in most cases in China. In open-type heat exchange systems, the low-boiling substances and moisture generated by the heat transfer oil under heating conditions tend to separate during operation, releasing volatile gases and steam; as a result, the heat transfer oil ends up in a liquid-gas mixture state. This liquid-gas mixture is prone to surge, pulsation, and steam hammer effects under the high temperature, high speed, and low pressure conditions present in such systems. Moreover, contraction in high-pressure areas can lead to the formation of cavities, causing cavitation. Devices operating in this condition not only have low operational efficiency, but their reliability and safety also decline, as well as the service life of the heat exchange system. In particular, when the heating temperature exceeds 300°C and the saturated vapor pressure of the heat transfer oil at its operating temperature becomes greater than the hydrostatic head at the location of the expansion tank, the aforementioned contradictions become even more pronounced. In severe cases, a “breakdown condition” may occur, wherein the heat transfer oil rapidly vaporizes, rendering the equipment completely inoperable. Any oil will oxidize in the air; heat transfer oil is no exception. The oxidation rate of oil is proportional to the surface area of contact between the oil and oxygen. In an open system, when heat transfer oil comes into prolonged contact with air over a large surface area, it gets oxidized to form organic acids. These organic acids further promote the polymerization of the heat transfer oil, causing it to condense into a paste-like substance. This increases its viscosity, thereby slowing down its flow rate and prolonging its residence time in the furnace tubes. As a result, not only is the heat transfer efficiency reduced, but the degradation of the heat transfer oil is also accelerated, shortening its service life and compromising the safe and stable operation of the system. Closed systems generally use nitrogen or a cold oil sealing device to isolate the heat transfer oil from air. In a closed system, the heat transfer oil operates in a sealed environment, which effectively prevents its oxidation and degradation. This helps to extend the service life of the heat transfer oil, reduces its evaporation, and avoids the problems associated with open systems. It fully meets the requirements for energy conservation, emission reduction, and environmental protection. The use of a closed nitrogen system requires a nitrogen source; otherwise, an additional nitrogen generation system must be installed. This complicates the equipment involved in the heat transfer oil system and has certain impacts on its operation and maintenance. It increases the overall complexity of the system, raises equipment investment costs, and elevates the expenses related to production operations and maintenance, thereby making it difficult to popularize and implement. At present, it is only used in large enterprises, large thermal oil heating systems, and enterprises with a nitrogen gas supply in China. For enterprises that have no nitrogen gas supply, possess relatively small thermal oil systems, and have limited financial resources, cold oil seal devices are often used to isolate the thermal oil from the atmosphere. This effectively protects the thermal oil from oxidation by air, thereby prolonging its service life.

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