Heat Recovery: Radiation & Convection Recuperators

In these regenerators the heat energy transfer between primary and secondary fluid is primarily by radiation and its installation is always done in a vertical stack.This type of exchange is strongly favoured by temperature, so that these retrievers are especially suitable in the following cases:

- When the smoke temperature is higher than from 1000 to 1050 ° C.
- When the components of smoke are aggressive or high particulate matter content.

There are two types of radiation recuperators, the double-shirt and basket of tubes.

The recuperator jacket is made by two concentric cylinders in which the secondary fluid flowing through the well annulus parallel to the axis of the recuperator or helically, counter current or parallel flow. It is suitable for working pressures up to 2,000 mm. C.A.

Its main advantages are:

- Reduced fuel consumption under certain circumstances may exceed 40% by preheating combustion air.
- No pressure losses in the fumes as a result of geometric design of this type of retrievers.
- Compact design facilitates installation in the chimney smoke.

Such successes are listed in frit smelting furnaces, glass furnaces, aluminum furnaces, forging furnaces in the steel industry, etc.

In the salvage radiation Shopping tubes inside the shirt is replaced by a basket disposed annular tube, which circulates the air, in order that transfer of heat by radiation may be pursued.

Among its main advantages would be:

- Better air distribution resulting in a uniform temperature of the tubes of the basket.
- Greater resistance to corrosion by a suitable choice of material.
- Maintaining appropriate because the element of exchange (a basket of tubes) is independent of the frame.
- Increased work pressures that may reach 6000 mm. C.A.

Such successes usually are installed in furnaces for glass industry.

Joint facilities are used in those cases in which it is intended to fumes heat from most is advisable to use facilities consisting of two or more regenerators connected in series.

This system avoids the use of a single large recuperator thereby leading to higher functionality and maintenance problems as well as increased cost in manufacture.

Convection Recuperators

As its name suggests, these recuperative heat transfer between the primary and secondary fluid is carried out mainly by convection. They include a full contact between the gases and the tubes that form the recuperator, so they are particularly suitable for the following cases:

- For operating temperatures below 1000 - 1050 ° C.
- For gas streams or smoke, moderately clean (absent of particulate matter) and not particularly corrosive components.

They fall into two types:
- Loose tube bundles in a channel for introducing smoke horizontal (underground or overhead) or vertical (FP).
- You make tubular metal frame built where the temperature of smoke is not very high and they prefer a compact package for easy mounting. These can also be mounted vertically or horizontally.

An accurate thermal dimensioning can achieve the best balance between the exchange surface and the pressure loss and exchange between surface and space occupied. This, together with the consideration of the risk of corrosion and knowledge of the sites will be located, guarantees the use of equipment suitable to the needs of customers.

Furthermore, the optimal selection of materials used ensure durability of the equipment, with an advantageous quality / price / performance.

Finally, note that the selection and calculation of each recuperator specifically allows to achieve optimum energy recovery, with economic savings in many cases allows a return on investment for the purchase of equipment in a short time.