The characteristics of graphite heat exchangers and common sense of classification

Graphite heat exchangercharacteristic

The graphite heat exchanger has good corrosion resistance, the heat transfer surface is not easy to scale, and the heat transfer performance is good. However, graphite is easy to brittle and has low bending and tensile strength, so it can only be used at low pressure. Even if the block-like structure is the best under pressure, its working pressure is generally only 0.3 to 0.5 MPa.

Graphite heat exchangers are expensive, bulky, and rarely used. It is mainly used for heat exchange of corrosive media such as hydrochloric acid, sulfuric acid, acetic acid and phosphoric acid, such as the condenser of acetic acid and acetic anhydride. Mainly used in chlor-alkali chemical industry, petrochemical industry, fluoride salt, titanium dioxide, zirconium industry, chloroacetic acid, chlorinated paraffin, monocrystalline silicon fluorine chemical industry and other production occupations.

Classification of graphite heat exchangers

1. Block hole type: It is assembled by several block graphite elements with holes.

2. Shell and tube type: The shell and tube heat exchanger occupies an important position in the graphite heat exchanger. According to the structure, it is divided into two types: fixed type and floating head type.

Shell and tube heat exchanger (shell and tube heat exchanger) is also called shell and tube heat exchanger. It is a partition type heat exchanger with the wall surface of the tube bundle closed in the shell as the heat transfer surface. This kind of heat exchanger has a simpler structure and reliable operation. It can be made of various structural materials (primarily metal materials) and can be used under high temperature and high pressure. It is the most widely used type.

3. Plate type: The plate heat exchanger is made by bonding graphite plates. In addition, there are submersion type, spray type and double-pipe type (see snake tube heat exchanger, double-pipe heat exchanger).

The plate heat exchanger is a new high-efficiency heat exchanger made up of a series of metal sheets with certain corrugated shapes. Thin rectangular channels are formed between the various plates, and heat exchange is carried out through the half plates. Plate heat exchangers are ideal equipment for liquid-liquid and liquid-vapor heat exchange. It has the characteristics of high heat exchange efficiency, low heat loss, compact and light structure, small footprint, convenient installation and cleaning, wide application, long service life and so on. Under the same pressure loss, the heat transfer coefficient is 3-5 times higher than that of the tube heat exchanger, the floor area is one-third of the tube heat exchanger, and the heat recovery rate can be as high as 90% or more.