To solve the scaling problem of carbon fiber composite tubular graphite heat exchanger, it is necessary to control the medium characteristics from the source. Minerals such as calcium and magnesium contained in the heat exchange medium, as well as suspended particles, are the main causes of scale and fouling. Before the medium enters the carbon fiber composite tubular graphite heat exchanger, reducing the content of these substances through pretreatment can effectively reduce the possibility of scaling. For example, softening the water to remove ions that are prone to scale formation, or removing suspended particles by filtering, so that the medium entering the carbon fiber composite tubular graphite heat exchanger remains relatively pure. This pretreatment is not a one-time operation, but needs to be continuously adjusted according to the changes in the medium composition to ensure that the medium entering the carbon fiber composite tubular graphite heat exchanger is always in a state that is not easy to scale, fundamentally reducing the subsequent cleaning burden.
Optimizing operating parameters is also critical to inhibit scaling. Carbon fiber composite tubular graphite heat exchanger operating at too high or too low a temperature may accelerate the formation of scaling. When the temperature is too high, some components in the medium are easy to precipitate due to the decrease of solubility and adhere to the pipe wall; if the temperature fluctuates too much, the thin scale that has been formed will break due to thermal expansion and contraction, which will provide attachment points for new scale. Maintaining a stable heat exchange temperature and flow rate, so that the medium flows smoothly in the pipe, can reduce the chance of component precipitation and deposition. In addition, it is also important to avoid the operation of the carbon fiber composite tubular graphite heat exchanger under overload. Excessive load will cause the medium to stay in the pipe for too long, increasing the chance of contact between the scaling material and the pipe wall. Reasonable control of the load can allow the medium to pass through the heat exchange area quickly and reduce the risk of scaling.
Regular cleaning is a necessary measure to remove existing scaling, and it is particularly important to choose a cleaning method suitable for carbon fiber composite materials. Traditional mechanical cleaning may damage the surface structure of the composite pipe, while some chemical cleaning agents may react with carbon fiber or graphite, affecting the performance of the carbon fiber composite tubular graphite heat exchanger. Using mild physical cleaning methods, such as high-pressure water washing, can effectively remove soft scale on the pipe wall without damaging the composite pipe. For harder scale, a special neutral detergent can be used to soften the scale by soaking before washing, and avoid using strong acid and alkali substances. The frequency of cleaning needs to be determined according to the scaling rate. It should not be too frequent to affect normal operation, nor too long to make the scaling harden and difficult to remove. It is necessary to find a suitable cleaning cycle in practice.
Using the characteristics of carbon fiber composite materials to design anti-scaling structures can reduce the adhesion of scale from the carbon fiber composite tubular graphite heat exchanger itself. The surface smoothness of carbon fiber composite tubes is better than that of traditional graphite tubes, and this characteristic itself is not conducive to the adhesion of dirt. On this basis, by optimizing the inner wall shape of the pipeline, such as adopting a smoother curved surface design to reduce the dead corners of the medium flow, the medium can have a certain scouring effect on the tube wall during the flow process, taking away the tiny scale particles that are about to attach. At the same time, the thermal conductivity of carbon fiber composite materials is relatively uniform, which can avoid the formation of scaling hotspots due to excessive local temperature, make the temperature distribution of the entire heat exchange surface more balanced, and reduce the area where scaling is concentrated.
Real-time monitoring during operation can timely detect signs of scaling, which is convenient for early treatment. By observing the changes in the heat transfer efficiency of the carbon fiber composite tubular graphite heat exchanger, if the heat transfer effect is significantly reduced, it may be that scale has formed on the tube wall; monitor the changes in the inlet and outlet pressure difference. If the pressure difference increases, it means that the flow area in the tube has decreased due to scaling. These monitoring do not require complex instruments. Operators only need to pay attention to the changes in relevant indicators during daily operation, establish a simple recording system, and compare data from different periods to promptly determine whether scaling has occurred. Once signs of scaling are found, timely mild cleaning measures can be taken to avoid further hardening of scaling and prevent small problems from turning into major failures.
Different treatment strategies are required for different types of scaling. Scale is mostly formed by mineral deposition, which can be adjusted by adjusting the pH value of the medium to a range that is not easy to precipitate; while scale may come from organic matter or impurities in the medium, which requires enhanced filtration or the use of targeted cleaning agents. In chemical production, the composition of the medium is often complex and changeable, and scaling types may also appear mixed, which requires operators to be familiar with the characteristics of the medium being treated, judge the type of scaling based on its appearance and composition, and then choose the corresponding treatment method. For example, the scale formed by organic matter may be more suitable for biodegradation, while mineral scale needs to be removed by physical or chemical methods. Differentiated treatment can improve the descaling efficiency and protect the carbon fiber composite tubular graphite heat exchanger from damage.
Deep maintenance after long-term use can completely remove stubborn scale and restore the performance of the carbon fiber composite tubular graphite heat exchanger. Even if daily maintenance is in place, a small amount of scale may still accumulate after long-term operation, especially in the curved parts of the pipe or areas with slow flow. At this time, a thorough shutdown cleaning is required. The circulating cleaning method can be used to allow the detergent to flow continuously in the pipe to gradually dissolve the stubborn scale layer; for local scale that is difficult to remove, manual cleaning can be used, but attention should be paid to the choice of tools to avoid scratching the surface of the carbon fiber composite pipe. After deep maintenance, the performance of the carbon fiber composite tubular graphite heat exchanger needs to be tested to ensure that the scale has been completely removed. At the same time, check whether the pipeline is damaged by scale and repair it in time before putting it into use to extend the service life of the carbon fiber composite tubular graphite heat exchanger.
