Standards for the selection of electric heating of technological pipelines at petrochemical plants
Electric pipe heating technology is a new type of heat preservation and freezing protection technology. It has found wide application in the production of various industries.
The principle of electric heating: when the pipe is working, due to the lowering of the ambient temperature, the molecules are compressed, when the carbon particles pass through the circuit, the heater begins to heat up, when the temperature rises, the molecular electric plastic can rapidly expand the carbon particles, open circuit, increased resistance and closed circuit formation. which further reduces the heating power, Increased heating power with heating wire.
With the rapid development of my country's economy and society, the traditional steam heat exchanger technology has been replaced by new technology. In our country, we have carried out extensive research in the field of electric heating technology and made significant progress. The process of heat preservation by electric heating should be considered in the following situations: first, it can compensate for the heat loss of the environment inside the pipeline so that the temperature on the supply meets the needs of the pipeline; second, the heat loss will create condensate in the gas transported through the pipeline, third, the operating time due to a sharp drop in average pressure. The pipeline is easy to shut off; fourth, during the shutdown during transportation, the medium temperature in the pipeline drops sharply due to heat loss, as a result of which the medium is not blown and the pipeline is easily solidified; fifth, due to the heat loss, the pipeline medium will partially crystallize; Sixth, freezing point of the environment and the environment or higher than the environment.
Electric heating is commonly used in the transportation of pipelines, valves, and pumps in industries such as petroleum, chemical, pharmaceutical, engineering, and food. In recent years, electric heating technology has been widely used to solve problems that are difficult to solve with traditional heating methods, such as long heat pipes, small heat pipes, and thermoplastic non-metal pipes.
Electric heating technology is widely used not only to ensure heat transfer through the pipeline, but also to provide small gradient, long time, no pollution, safety and reliability, high price, simple design, saving resources, remote control, long-term use. Use etc. D., and the need for thermal energy is much lower than that of electric heating, suitable for long-term use, this is the direction of the country's technology development, and it is worthy of long-term national development and promotion.
Electric heating cable is a heating method that uses insulation resistance or resistance heating wire to create a temperature after power supply. It can automatically adjust the output temperature and reasonably maintain the process temperature requirements to keep warm, raise the temperature and protect the heating equipment from freezing. The insulation and antifreeze effect of the container is very good.
Transport of heavy oil through the pipeline over long distances and long-term retention in the pipeline will result in a drop in temperature due to heat dissipation and increased viscosity, which will cause the pipeline to be blocked by freezing or condensation-related accidents. Electric heating is widely used as effective insulation of pipelines and anti-freeze protection.
According to the statistics of the Hydrometeorological Center, the average daily minimum temperature at the location of the CNPC tank farm is 5 ° C, and the average daily maximum temperature is 14 ° C. Since the freezing point of the PX is about 15 °C, the supply pipeline needs heat preservation and heating. The oil depot has been in operation for many years without a stable source of steam, therefore, this project is considering the use of electric heating technology.
Long-distance crude oil pipelines with a high paraffin content with freezing temperatures above 50 °C. According to the requirements of the production plan of the plant, the volume of oil transportation through the pipeline is 150 thousand rubles. Tons per year, maximum-200 thousand. Tons per year.. According to the thermodynamic analysis of the pipeline, the initial supply temperature of the pipeline is 80 ° C (TN), and the temperature of the end entering the tank is 60 ° C (Tu). Since the transportation temperature needs to be adjusted according to the time of year, it sometimes needs to be transported by heat.
In petrochemical engineering, trunk infusion pipelines are the lifeblood of the factories. The temperature in the northern region is too low in winter and the pipeline needs to be insulated to compensate for the heat loss due to the low temperature in winter to ensure the normal operation of the pipeline.
The toughness of the asphalt is greatly affected by the temperature. When the temperature decreases, the toughness of the asphalt increases, and the drop in resistance of the asphalt during pipeline transportation increases; when the temperature falls below the freezing point, the asphalt solidifies, causing the pipeline to clog and the conveyor belt to come to trouble. Therefore, electric heating and heat preservation during the transportation of asphalt are very important.
To solve many problems in the "three high levels" crude oil extraction process, the thermal energy generated by the electric heating is used to heat the crude oil in the oil pipe throughout the process to improve the fluidity of the crude oil. Effectively solve various technical problems encountered in the operation of high-condensation, high-viscosity and high-paraffin crude oil, and achieve the goal of improving the productivity and efficiency of oil wells.