Graphite heat exchanger-the principle of graphite heat exchanger

Graphite not only has acid corrosion resistance, but also has good thermal conductivity. The graphite core is made into a block-hole structure separated vertically and horizontally. When the two media pass through each other, the high-temperature medium continuously transfers heat to the graphite. Heater, the low-temperature medium continuously gets heat from the heat exchanger, thus realizing heat exchange. Graphite heat exchanger is a heat exchanger made of graphite for heat transfer components. The graphite used in the manufacture of heat exchangers should be impermeable, and impregnated impermeable graphite and pressed impermeable graphite are commonly used. According to its structure, graphite heat exchangers can be divided into three types: block type, shell and tube type and plate type. Block hole type: It is assembled by several block graphite components with holes. Shell and tube type: The shell and tube heat exchanger occupies an important position in graphite heat exchangers. According to the structure, it is divided into two types: fixed type and floating head type. Plate type: The plate heat exchanger is made by bonding graphite plates.

Graphite heat exchanger-the advantages and disadvantages of graphite heat exchanger

Advantages: Suitable for most organic solvents and composite media that do not oxidize or weakly oxidize strong acids, alkalis, salt solutions, organic acids. The thermal conductivity is higher than many metals, second only to copper and aluminum, 2 times larger than carbon steel, 5 times larger than stainless steel, ranking first among non-metallic materials, and suitable for making various heat exchange equipment. The linear expansion coefficient is small, high temperature resistance, heat shock resistance. The surface is not easy to scale and no pollution. Good machining performance. Low density and light weight.

Disadvantages: Graphite heat exchangers are divided into block hole type and shell and tube type. The main disadvantage of the block-hole graphite heat exchanger is that once a leak occurs, it is difficult to find and repair. The disadvantage of the shell-and-tube graphite heat exchanger is that the strength of the graphite tube is relatively low, and the steam pressure used cannot exceed 0.15MPa; the flow rate of the heated medium is low and can only be controlled at 2 to 3m/s; the temperature difference between inlet and outlet can only be controlled within 2 ~ 4℃, the heat exchanger has a large volume.

Graphite heat exchangers have been using graphite tube plates from the earliest bonded graphite heat exchangers to the current exchangeable tube-and-tube heat exchangers. Many domestic chemical companies have used them for more than ten years. Equipment scrapping caused by problems with tube sheets. It has a long history and plays an indispensable role in our industrial production.

Characteristics of graphite heat exchanger

1. Because graphite has strong high temperature resistance, this also makes the graphite heat exchanger lose weight and coefficient of thermal expansion even if it is burned by ultra-high temperature arc, and its strength will increase with the increase of temperature;

2. The conductivity of graphite is one hundred times higher than that of general non-metallic minerals, and the thermal conductivity is far more than that of metal materials such as steel, iron, lead, etc., so the thermal conductivity of graphite heat exchangers decreases with increasing temperature;

3. The lubrication performance of graphite heat exchanger depends on the size of the graphite flakes. The larger the flakes, the smaller the friction coefficient and the better the lubrication performance;

4. Graphite heat exchangers have good chemical stability at room temperature, and can resist acid, alkali and organic solvent corrosion;

5. Graphite heat exchanger has good thermal shock resistance;