TEIDE REFRACTORY SOLUTIONS QUANTIFIES THE EXCHANGES IN ITS TUNNEL KILN.

The Technical and Simulation Departments of TEIDE REFRACTORY SOLUTIONS,S.L., work together to be able to develop its strongly committed to increase knowledge of the thermal phenomena that occur in the tunnel kilns of our customers. Just through this way we can offer optimized solutions to their needs.

¿What is a tunnel kiln?

A tunnel kiln is a heat exchanger, in which the air and the kiln car circulate in opposite

General view of the tunnel kiln of TEIDE REFRACTORY SOLUTIONS from its plant in CALANDA, with the kiln on the left

The following figure outlines the operation of the tunnel, with opposite directions of load/air circulation kiln.

In the first step, the air is hotter than the load, producing the firing. In the second step, the set load/kiln car is warmer than the air, producing the partial energy recovery.

Operation outline of a tunnel kiln. Source: TEIDE REFRACTORY SOLUTIONS.

¿What happens to my system load-wagon?

When the wagon and load enter in the furnace, the air is warmer than the system load-kiln car; this produces the heat exchange of air to the load and the wagon which allows the firing of the load. The burners, responsible for placing the heat flux in the kiln, are located on the central section. At the end of the way of the kiln car, the load and the kiln car are hotter than the air, so the load and the kiln car get cooled and transferred part of its heat to the air of the kiln, allowing partial heat recovering and this fact increase the efficiency.

We have to bear in mind, that during the way, part of the heat is lost by the bottom of the kiln car, becoming unrecoverable heat.

Finally, at the exit of the furnace loading and kiln car accumulate part of the heat that have not returned to the kiln, called sensible heat.

If they do not have auxiliary systems for the recovery of this heat, this energy is also lost.

TEIDE REFRACTORY SOLUTIONS, S.L., designed kiln cars that minimize the energy consumption. Using our kiln cars customers get to use less energy, so that their processes are economically more efficient.

¿Can the heat exchange be quantified?

TEIDE REFRACTORY SOLUTIONS, S.L., committed to simulation using HEATEIDE® to quantify heat exchanges that occur in the process above described.

The first step consists of defining temperature ramp and the geometry of the kiln car, since heat exchange depends on both the geometry and composition of the wagon as well as the temperature ramp.

Following, by HEATEIDE® is possible to gets the temperature distribution for different moments of time.

Distribution of temperature in a wagon section of TEIDE REFRACTORY SOLUTIONS, S.L.

Then the data is analyzed. The attached graph collects the accumulated energy and the exchange of heat between the furnace and the kiln car.

Energy consumption and heat flux for a design of a wagon of TEIDE REFRACTORY SOLUTIONS, S.L.

The red line shows the heat flow between the air of the kiln and the kiln car. It can be appreciated that in the first step is positive, which means that the air heats de kiln car, while in the second step is negative. T his fact produces only a partial energy recovery.

The dashed blue line shows the heat flux that is lost through the bottom of the kiln car. It’s important an adequate design of the kiln car that minim ize these losses since they will never be recovered.

The hatched area shows the consumed energy by the kiln car in the process. Part of the consumed energy is invested in increasing the temperature of the components of the kiln car, while another part extends by the background. In the first step is shown how the kiln car takes heat from the kiln. In the last step, is shown how the kiln car returns part of the heat to the kiln. Finally, at the exit of the kiln, the kiln car maintains part of the absorbed heat.

The grey area shows the fraction of consumed energy that is extended by the background of the kiln car during the firing process.

Through the numerical simulation done by TEIDE REFRACTORY SOLUTIONS, S.L, is possible to quantify the energy consumption at project stage. By this way of working together with our customers, TEIDE is able to offer the most optimized refractory solutions for them.

Do not hesitate to contact with our Commercial Department to request additional information.