Macedonian site uses heat exchangers to recover energy and save money


The Johnson Matthey site in Macedonia makes catalysts for the automotive industry. Until 2011, the waste heat from the combustion process was being discharged to the air – meaning that valuable energy was simply being lost.

A project to install two heat exchangers has changed all that. The principle behind a heat exchanger is that the energy of a heated medium – fluid, gas or air – can be reused by passing the hot medium close to a cooler medium. In this case, heat exchangers were fitted to the flue gas exhaust. The heat from the gases is now used to preheat the air going into the dryers that are used in the catalyst manufacturing process.

The heat exchanger runs cold air and the hot exhaust gases from the burners past each other – the cold air, once heated, is used in the dryers. In this way, all of the energy from the exhaust gases is used, instead of going up the chimney stack.

Two identical systems were installed, one on each process line. They came into operation in mid 2011 and together save 500kW of energy that would otherwise be supplied by natural gas. This represents a double saving, both on energy and the money formerly spent on natural gas.

The capital cost of the project was modest, with payback in only 18 months. Saving energy is a key area for the process improvements that are helping the Johnson Matthey to achieve its sustainability goal of halving key resources by 2017.