Security countermeasures

(1) Ensure equipment safety

The heat-conducting oil heating system should be managed as a pressure equipment, and the heating equipment must be intact, otherwise the consequences will be very serious. During use, the wall thickness and pressure strength of the equipment should be checked regularly, and pressure gauges, safety valves and vent pipes should be installed on the equipment and pipelines.

(2) Strict safety operation

When using a thermal oil furnace, strictly control the temperature not to exceed 350°C to prevent temperature rise and overpressure, which may cause danger. In order to avoid overheating of the pipe wall on the heating surface of the heat transfer oil, the flow of the heat transfer oil should be in a turbulent state, that is, Reynolds number Rc>10000, and have a certain flow velocity to reduce the thickness of the boundary layer when it flows over the heating surface. The circulation pump of the heating medium must not be stopped during the heating operation. When the thermal load is reduced or temporarily out of service, the bypass return valve should be opened to adjust the system flow so that the heat transfer oil in the pipe has sufficient flow and velocity.

When the heating furnace is started, the heating surface pipe and the empty pipe of the system pipe shall be preheated. When starting to ignite and raise the temperature, due to the low temperature, high viscosity, low flow rate and thick film of the heat transfer oil, the heating rate must be strictly controlled, generally below 40-50°C/h to avoid local overheating. When the temperature of the circulating heat transfer oil is high but the temperature of the heating equipment does not rise, you should not blindly increase the temperature of the heat transfer oil outlet. Instead, you should look for the cause from the heating equipment, such as fouling and blockage. Use heat transfer oil to heat, and pay attention to the relationship between temperature and pressure at the beginning of driving. If the pressure is too high and the temperature is too low, it means that there is water, and it should be exhausted in time; if the pressure is too low and the temperature is too high, it means that the amount of heat transfer oil is insufficient, and the heat transfer oil should be added. When the system stops running, the circulating pump of the heat transfer oil should continue to run for a period of time. After the heating medium has cooled, put all the heat transfer oil in the system back into the storage tank, especially if there is no leftover in the heating surface.

(3) Ensure that the heat transfer oil enters water

It is strictly forbidden to mix water or other low-boiling impurities and flammable and explosive substances in the heat transfer oil. When driving, the water in the system should be drained first, and then the intake valve and check valve should be opened, and the water in the heating medium should be heated according to the regulations; the newly changed or added heat transfer oil must be preheated and dehydrated before being added; When moisture is present, the air valve should generally be opened first, and then the temperature of the heat transfer oil should be raised to 150°C with a small fire at a heating rate of 5°C/h to make the moisture escape. Then close the vent valve and raise it to 250°C at a temperature rise rate of 10°C/h. During the heating process, if you hear the sound of water hammer or see that the pressure is too high, you should immediately open the vent valve to expel water vapor, and then close the vent valve and drive. When the furnace is shut down, the steam valve of the heat-conducting oil furnace should be closed after the heated materials are released to prevent the materials from leaking into the system.

(4) Remove coking and scaling

In production practice, it is safe for the coking thickness to be less than 2mm, and the coking layer in the furnace tube is between 0 and 1.5mm. At this time, the continuous storage of the coke layer is roughly balanced with the amount of melting washed by the heating medium. The thickness of the coke layer in the furnace tube can be measured with an ultrasonic thickness gauge.

A filter should be installed at the inlet of the circulating pump to filter out the suspended polymer caused by chemical changes and the carbon particles precipitated by local overheating. The filter should be easy to disassemble and replace in order to clean up the slag and impurities regularly to ensure the filtering effect.

(5) Strengthen safety management

We must pay attention to the development and implementation of technical specifications and management regulations for the operation of heat transfer oil heating equipment, and strictly abide by relevant laws, regulations and safety operating procedures. The heat conduction oil heating operation should have a complete emergency treatment plan, especially to prevent overflow, spraying, leakage, overload and disease operation. Once a leak occurs, it should immediately plug the leak and replace the insulation cotton.

(6) Set up safety devices

Set the temperature, pressure, flow, and liquid level automatic adjustment system, alarm system and safety relief device, and ensure that the instruments and meters are sensitive and easy to use. During the heating operation, if a sudden pressure rise occurs, the vent valve should be opened immediately to relieve the pressure, and the heating medium pipeline valve leading to the heating device should be closed.

Various temperature, pressure and liquid level devices