Vahterus PSHE EGE – Optimising Waste Heat Recovery Systems

In the market, there is a need for special plate & shell hheat recovery units. In the future, more and more environmental limitations and regulations will need to be taken into consideration with new industrial installations. With the Vahterus EGE, we aim to fill a significant gap in heat exchanger markets.

In industrial processes, it is common that waste heat is generated in addition to actual process operations; in the past, the waste heat was dumped into the atmosphere with considerable losses in energy and costs. The Vahterus EGE unit offers a concrete solution to return waste heat to the process and achieve remarkable savings in the system’s energy costs.

After years of working together with Spirax Poland, the first EGE-installation was realised for a Polish livestock food producer in May 2012. In this specific installation, the primary side boiler exhaust gases were used for producing hot water on the secondary side. Direct integration with the boiler body made the installation work convenient for the end customer.

After receiving the control data from the site, it was clear that the requested very low-pressure drop limit was being maintained and the calculated capacity achieved. With the EGE open-frame construction it is possible to reach the low-pressure drop needed in exhaust systems, while the unit size is compact and light. Moreover, CO2 emissions were reduced.

At the end of April 2012, the end-client commissioned a gas-fired boiler fitted with the first EGE-PSHE unit. ‘Since its installation, the Vahterus EGE has been operating in three shifts, trouble free’, says Maciej Goszcz of Spirax Poland.

The water-level control in the boiler is regulated by a master/slave system. The slave controls the flue gas temperature after EGE, while the master controls the level in the boiler, modifying the set point temperature of the slave controller built into the inverter-driven pump. The start/stop of the pump is linked to the firing cycle of the burner. This prevents the EGE from being heated in no-flow conditions.

The boiler capacity is 1,6t/h of steam at 8 bar. The end-user has reported up to 5% savings on gas. The payback time of the product depends on the price of gas, the number of shifts the boiler operates and the total cost of the investment. In this particular case, the installation was carried out during two consecutive weekends, limiting the downtime of the plant to a minimum. Overall, the estimated payback time is under a year.

The EGE type with an openable construction was introduced at the Energy Fair 2012 in Tampere, Finland. The Vahterus EGE-PSHE can handle high gas and liquid inlet temperatures. Different frame and plate materials are available, which makes the unit resistant to corrosion for several gas and liquid types. By using waste heat (e.g. exhaust gas) it is possible to produce hot water or steam on the secondary side of the unit. Vahterus can provide the unit with an openable frame construction to make mechanical cleaning of the gas side of the unit easier.

With this compact unit, high levels of heat recovery can be achieved with minimal reorganisation of the process system and remarkable savings can be made in a short time.

Tuomas Aikkinen

Key Account Manager