Permeable wall furnace

Zerontec is actively researching applications of porous ceramic membranes for radiation enhancement in high temperature furnaces and process plant. Read on .....

In a porous wall furnace, the hot combustion products flow through the permeable wall before exhaust to atmosphere. The permeable ceramic offers a very high specific surface area to the combustion products which leads to a high rate of interstitial convective heat transfer within the wall. This captured energy is then converted into useful radiation flux into the furnace space resulting in a net enhancement of heat transfer, a reduction in combustion product exhaust temperature and a net energy saving. The technique was first demonstrated in the 1940's by Gunn et al [1], and more recently in Japan by Professor Echigo [2]. With the development of new porous ceramic materials able to endure the high thermal shock, and with the drive towards more intensified heat transfer processes, we believe this technology is worth a second lease of life.

On a gas-fired furnace, the potential benefits are:

	Energy saving and reduced emissions (If it is a recuperative furnace, flue gas entry temperatures are reduced, leading to lower air preheats, and lower NOx - without loss of efficiency).
	Fast heat up times (The permeable wall become radiant in a few minutes from start-up)
	Possible improved temperature uniformity on account of the increase in radiant heat transfer.

Potential Applications

Any application where the main mechanism of heat transfer is by thermal radiation from hot gases e.g. furnaces, dryers, reactors.

Anderson R.H., Gunn D.C. and Roberts A.L., Use of Permeable Refractories for Furnace Construction, J.Inst.Fuel,1944.
Echigo R., Effective Energy Conversion Method Between Gas Enthalpy and Thermal Radiation and Application to Industrial Furnaces, Proc.7^th International Heat Transfer Conf., Vol.6, p361-366, 1982.

The permeable wall concept has recently been demonstrated in a Carbon Trust funded Applied Research project involving Warwick University, Glamorgan University, Foseco and Hotwork Combustion Technology Ltd. For further information please download the papers listed on the home page.