Air heater is an electrical heating equipment which mainly heats the gas flow. The heating element of the air heater is a stainless steel electric heating pipe. The inner cavity of the heater is provided with multiple baffles (guide plates) to guide the flow direction of gas and prolong the residence time of gas in the inner chamber, so as to fully heat the gas, make the gas heated evenly and improve the heat exchange efficiency. The heating element of air heater is stainless steel heating pipe, which is made of seamless steel pipe filled with magnesium oxide powder with good thermal conductivity and insulation. When the current passes through the high temperature resistance wire, the generated heat diffuses to the surface of the heating tube through the crystalline magnesium oxide powder, and then transfers to the heated air to achieve the purpose of heating.

Influencing factors:

1. Increasing the gas inlet velocity of the air heater can enhance the convective heat transfer of the electric air heater, and reduce the surface temperature of the electric heating element in the air heater, which is not only conducive to extending the service life of the electric heating element of the air heater, but also reducing the heat loss of the electric air heater. Therefore, the efficiency of the air heat exchanger is improved, but if the speed is too high, the pressure loss will be caused The loss increases sharply, which is not conducive to the improvement of heating efficiency.

2. If other conditions remain unchanged and the surface load is changed, the wall temperature of the electric heating element in the air heater will change linearly. If the surface load increases, the wall temperature of the electric heating element will increase, which will reduce the service life of the electric heating element in the air heater. However, if the surface load is too small and the wall temperature is too low, the efficiency of the heat exchanger of the air heater will be reduced It is important to choose the surface load of electric heating element.

3. When the final air temperature T2 in the air heater increases, due to the increase of air viscosity and the decrease of gas Reynolds number, the convective heat transfer intensity decreases, and the surface temperature of the electric heating element in the air heater rises at the same time. The infrared carbon sulfur analyzer increases the heat dissipation loss, thus reducing the efficiency of the heat exchanger. When T2 increases too much, the surface temperature of the electric heating element will also increase greatly, which makes the general electric heating element unable to bear. Therefore, the increase of T2 is usually limited by the heat resistance of the electric heating element material in the air heater.