This customer approached us looking for a solution for an indirect heating application. We designed, manufactured, installed and commissioned two large HET heaters. These units consist of a stainless steel concentric tube type heat exchanger, mounted within a stainless steel chamber to suit the clean environment requirements that are necessary in the food manufacturing industry. The outer casing is double-skinned and insulated with mineral wool to improve efficiency but also to protect external contact with the high temperatures achieved.
This HET indirect heater fires at around 250°C requiring a duty of 400kW using natural gas as fuel which heated process air to feed a spray dryer.
The sensitive nature of the product meant that the combustion by-products needed to be kept separate from the process air stream. Coupled with the demand for a high temperature rise the HET indirect-fired heater was chosen as the best solution. The specification of this project was such that we had to manufacture all aspects of the HET in stainless steel.
For added efficiency, we installed a process air recuperator on the inlet to the heater. The exhaust gases from the combustion chamber were ducted into our recuperator which meant the process air entering the HET was preheated.
Ensuring that the whole system was efficient, we also installed our PC2, using Siemens LMV3 controls, fully modulating gas and air burners. This enabled us to program the fuel/air ratio throughout the operating range delivering optimum efficiency.
Get in touch with our sales team to discuss how we can assist you with your combustion needs - sales@comtherm.co.uk