In order to obtain a high temperature in the reactor, the chemical reaction usually needs to be carried out under a certain temperature condition, so that the reactor is subjected to both pressure and temperature. There are usually the following methods for obtaining high temperatures:
1, water heating
It can be used when the temperature is not high, and the heating system has two types: open type and closed type. The open type is relatively simple. It consists of a circulating pump, a water tank, a pipe and a regulator for controlling the valve. When high pressure water is used, the mechanical strength of the equipment is high, the outer surface of the reactor is welded with a coil, and the coil has a gap with the wall of the kettle. The thermal resistance increases and the heat transfer effect decreases.
2, steam heating (steam heating reactor)
When the heating temperature is below 100 °C, it can be heated by steam below one atmosphere; in the range of 100~180 °C, saturated steam is used; when the temperature is higher, high pressure superheated steam can be used.
3. Heating with other media
If the process requires high temperature operation or if high pressure heating systems are to be avoided, other media may be used instead of water and steam, such as mineral oil (275-300 ° C), diphenyl ether mixture ([wiki] boiling point [/wiki] ] 258 ° C), molten salt (140 ~ 540 ° C), liquid lead (melting point 327 ° C) and the like.
4, electric heating (electric heating reactor)
The electric resistance wire is wound around the insulating layer of the reaction vessel body or is mounted on a special insulator at a certain distance from the reaction vessel, so that a small space gap is formed between the electric resistance wire and the reaction vessel body.
In the first three methods, a jacket is added to the kettle body of the reactor, and the temperature difference is large, so that the jacket and the casing of the reactor are subjected to temperature changes to generate temperature difference pressure. When using electric heating, the equipment is light and simple, the temperature is easy to adjust, and the pump, stove, chimney and other facilities are not needed, the driving is also very simple, the risk is not high, the cost is low, but the operating cost is higher than other heating methods, thermal efficiency Below 85%, it is suitable for heating temperatures below 400 ° C and where the price of electricity is lower.