How to design pipeline heat tracing technology

What isPiping heating?

Pipeline heating is to prevent the material crystallization in the pipeline, solidification or meet the needs of the process, the material to maintain a certain temperature and the use of a thermostat or heating mode.

Type of heat tracing: three types of companion tube, casing and electrothermal belt. It is in the heating protection of the pipeline around, if there is a steam pipe or fire, explosion-proof requirements of the media, should be used with the pipe or clamp casing type. If the heating protection system is not surrounded by steam piping, and the mediaNo fire, explosion-proof requirements, can be used to protect the power of the tropics. The more used in production is the steam pipe.

The following four kinds of heating media are commonly used in the process pipeline in the plant:

1, hot water: Suitable for dry in the operating temperature is not high or high temperature with hot media conditions, as a heat source of heating;

2, Steam: Generally used in the tube medium operating temperature less than 150 ℃ heat;

3, heat carrier: Generally used in the tube medium operating temperature greater than 150 ℃ of the jacket of the heating system. The common heat carrier has heavy diesel oil or distillation process greater than 300 ℃ distillate, biphenyl-biphenyl ether or hydrogenation biphenyl, etc.

4, Electrothermal: Electric heat tracing is not only applicable to the various conditions of steam heating and suitable for the heat-sensitive medium pipeline, it can effectively control the temperature, prevent the piping from overheating, and is suitable for piping or equipment dispersed or away from the point of supply, as well as the heat tracing of irregular type equipment (e.g. pumps).

There are four kinds of process piping heating modes, respectively:

1, with the hot pipeline with heat: the heat pipe installed in the process pipeline (ie, the director), with the heat released by the thermal media, all used to supplement the heat loss in charge of the medium;

2, external heat pipe with heating: With the heat pipe installed in the outside of the process pipeline, with heat pipe released by heating, a supplementary director (that is, the heat pipe) in the medium of thermal loss, the other part through the insulation layer to four weeks of the atmosphere. When the heat transfer required by the heat is larger (the director temperature is greater than150℃) or the supervisor requires a certain temperature rise, the need for multiple-tube heating, or the use of large heat transfer coefficient of the heat transfer cement, filled in the conventional external heat pipe and the director between, so that they form a continuous heat union, such direct heat transfer is better than the general convection and radiation heat transfer;

3, jacket with heat: the jacket with the heat pipe that is in the process pipe outside the installation of a casing, similar to the tube-sleeve heat exchanger for heating;

4, Electric heating: electric heating with the tropics installed in the process pipeline outside, the use of electrical resistance to supplement the process pipeline heat loss.

Under what circumstances should a piping companion heat be used

1, in the ambient temperature, from the outside to supplement the heat loss of the tube medium to maintain the pipeline conveying liquid temperature.

2, in the conveying process, due to heat loss caused by condensate and corrosion or affect the normal operation of the gas pipeline.

3, in the course of operation, due to sudden drop in pressure from the cold, may lead to ice jams or pipe play cold brittle crack pipe.

4, in the switching operation or intermittent shutdown period, the tube medium due to heat loss caused by temperature drop, but also can not vent or sweep line and affect the next delivery pipeline.

5, in the transport process, due to heat loss caused by cooling, resulting in the crystallization of the pipeline.

6, in the transport of high viscosity medium, due to heat loss caused by the temperature of the media after the increase in viscosity, so that the system resistance suddenly increased, the amount of transport decreased, not up to the minimum allowable amount of pipeline.

7, the transmission medium solidification point is equal to or above the ambient temperature pipeline.

The above is the small compilation of the relevant technologyPiping heatingThe small knowledge