Waste incineration plant - Netherlands

Challenge

Before entering the flue-gas cleaning system the flue gases from the waste incineration lines have to be reheated up to approximately 240°C. In the existing situation this was achieved with a natural gas-fired supplementary burner system, which was susceptible to malfunction and was costly to operate. Stork was asked to evaluate and redesign the existing situation.

Customer profile: The customer, based in the Twente region of the Netherlands, processes waste to produce energy. Over 90% of the waste is transformed into raw materials, building materials and energy. The installation consists of three waste incineration lines, burning approximately 90 Mg/hour of municipal waste. The steam is used mainly to produce electricity, but also as process steam for a nearby chemical plant and for district heating. This combination makes the plant one of the world’s most energy efficient waste incineration plants.

Solution

Stork analysed the process of the complete waste incineration plant and recommended the use of a heat exchanger fed with saturated steam to heat the flue gases. This ‘DAGAVO’ replaces the existing burner system. By using saturated steam to feed the DAGAVOs and feeding the condensate back to the deaerator, it was possible to reduce the steam extraction from the steam turbine, leading to a higher electricity output. The waste throughput in the incinerators was also increased, leading to a higher production capacity. The mechanical design of the DAGAVOs is robust and flexible, leading to high operating reliability and therefore high availability.The DAGAVOS were prefabricated in our workshop as complete assemblies. This approach allowed the downtime of the waste incineration lines to be kept to an absolute minimum. The project was executed by Stork on a turnkey EPC basis, including process and mechanical engineering, modification of the control system and the in-house fabrication of the pressure parts. Site erection, including scaffolding and insulation works, and commissioning were also executed by Stork.

Benefits

• Reduction of natural gas consumption

• Increase of production capacityRobust and flexible design

• High operating reliability and therefore high availability

• Payback time shorter than 1.5 years

• Turnkey EPC project execution – no interfaces to be managed by the customer