Low cost test unit
With our self-cleaning heat exchanger technology Klaren International can design shell & tube heat exchangers for zero-fouling operation.
Every client process is unique and therefore a pilot test is required to determine the overall heat transfer coefficient and to demonstrate the zero-fouling performance. In the past, such a pilot represented a section of the planned full-size heat exchanger applying the same temperatures and ΔTlog. This pilot was equipped with a minimum of 7 tubes of same tube diameter and length, as planned for the full-size heat exchanger.
The self-cleaning fluidized bed shell & tube heat exchangers consist of a vertical tube bundle with an upward flow of liquid and particles, of which the latter are made of glass, ceramic or chopped metal wire with diameters varying from 1.5 to 4 mm. At the outlet of the exchanger, the particles are separated from the liquid and returned to the inlet channel of the exchanger, distributed over the tubes and the cycle is repeated. The fluidized particles are responsible for scouring the tube wall and removing deposits at an early stage. They also increase the film coefficient, even at very low liquid velocities. Zero-fouling is guaranteed when the rate of removal of deposits by the particles exceeds the rate of precipitation of deposits | read more
Also the same type, size and volume fraction of the particles and the same superficial velocity were applied. Such a unique pilot, very often only suitable for one particular application for reasons of operating pressures, temperatures and material choice, could be quite expensive taking into account transportation, support construction, erection, installation of the connecting piping, instrumentation, commissioning.
To reduce the costs of a pilot test we have developed a low cost test unit that consists of a shell and tube heat exchanger with only one single tube and a particle separation and recirculation down-comer tube.
The particle separation/recirculation down-comer tube is a standard piece of equipment that can be used for different applications. The single-tube heat exchanger can be made by any work-shop even in case of Code requirements. For low cost installation, we recommend the mounting of this pilot along existing platforms and stairways in the immediate vicinity of the fouling liquid.
In this single tube test unit liquid flow, particle flow, porosity of the fluidized bed in the heat exchange tube, type of particles and particle size can be varied independently. The heat transfer performance, i.e. k-value, can be measured with the instrumentation, and optimized as a function of all relevant parameters.