On the choice of electric heating insulation type for viscous oil pipelines
my country is rich in heavy oil resources, but most of the heavy oil fields are difficult to exploit and the cost is high, which seriously limits their development. With the development of science and technology and the growing shortage of traditional oil and gas resources, heavy oil resources are gradually widely used. Valued, well-performing production prospects.
Heavy oil production uses electric heating to keep it warm due to the difficulty of leaking. Due to the high freezing temperature and the density characteristics of the heavy oil during transportation, as soon as the ambient temperature drops, the pipeline will freeze and block. To ensure the normal flow of super-heavy oil in the pipeline, maintain a certain operating temperature, and ensure good turnover in transportation, as with the electric heating of the well in production, an electric heating belt can be selected. For the pipeline to keep it warm.
Electric heating cables for fuel oil piping need to be selected with different characteristics of heating cables due to different pipe diameters, temperature requirements and actual environmental factors on site. Common electric heating cables include mineral insulated heating cables, constant power electric heating cables, self-regulating electric heating cables, surface effect electric heating cables, etc. D.
Self-regulating temperature heating cable is economical and suitable for short piping. If there are many taps, flanges and pump fittings on the pipeline, it is also recommended to use a self-regulating temperature heating cable. Since the self-regulating electric heating cable can be cut arbitrarily, the installation is simple. On the knee or flange, if the electric heating cable is wound or superimposed, there will be no high temperature phenomenon.
If the pipeline is long, such as several kilometers, it is possible to consider constant power series electric heating cables, because for pipelines within 3000 meters, only one serial electric heating cable can solve the heat preservation problem, that is, one circuit can be completed. In addition, the series of constant power electric heating cables has high temperature resistance, high heating temperature and uniform heating, which is suitable for freezing protection and heat preservation in industrial main pipelines.
With the greater length of the pipeline, extending for several kilometers or even tens of kilometers, products such as skin-effect electric heating cables can be considered.
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.