Eneco Bio Golden Raand: green energy with recycled wood chips

Back in 2007, Eneco, a leading Dutch utility company, was the first energy company in its operating area to choose a sustainable strategy. Over the years, it has become a leader in energy transition and one of the biggest investors in sustainable energy.

One of the company’s major investments is the Eneco Bio Golden Raand biomass plant, located in Delfzijl and supplied by Valmet. It has played a key role in enhancing the sustainability of Eneco’s energy supply since 2013. The plant produces sustainable electricity for 120,000 households and AkzoNobel Industrial Chemicals. It also supplies steam to Nouryon Chemicals. Both are industrial customers in its vicinity. Thanks to biomass utilization, the amount of CO2 emissions from energy production has been reduced by some 250,000 tonnes annually.

Valmet’s delivery included a 49 MWe biomass-fired boiler plant, a flue gas cleaning plant and stack, a feedwater system and a Valmet DNA automation system. The boiler utilizes circulating fluidized bed (CFB) technology and runs completely on recycled wood chips. The steam parameters are 127 MWth, 50 kg/s, 90 bar and 520 °C.

“We chose Valmet’s technology for our plant based on how Valmet presented themselves as a company, their knowledge and proven reliability in other projects,” says Marc Wegman, Director Industrial Assets at Eneco.

Fuel issues removed together

Not long after the start-up, ensuring the quality of recycled wood chips proved far more challenging with regard to combustion than had been expected.

“We faced some issues with the fuel and particularly with the chemicals, mainly chlorine, in the waste wood. This had a major impact on the wear and tear of the boiler parts, and especially on the superheaters. Valmet helped us choose better materials and protect parts within the boiler to prevent any damage. This made it possible to extend the time between outages,” Wegman explains.

In addition to the boiler modifications, Valmet has helped the plant measure fuel quality, and optimally tune and operate the process. For example, to optimize the combustion temperatures with the varying fuel quality, Valmet combines process expertise with analytical tools. “Big data analyses are being used to monitor our fuel and ensure that we won’t cross the lines of the fuel’s maximum chemical content threshold in the fuel,” adds Wegman.

Regular performance evaluation with analytical tools is part of the Valmet Industrial Internet (VII) offering, which has been developed to optimize process operations based on vast monitoring data.

Since we solved the fuel quality issue together, plant reliability and availability have been very high.

No surprises – thanks to a service agreement

According to the service agreement between Eneco and Valmet, the latter carries out all boiler maintenance work at the plant. All actions are planned well ahead for a one- or two-year period, so no nasty surprises lurk in the process.

Wegman continues: “The biggest benefits of the service agreement include the knowledge levels of Valmet personnel and the speed with which they can respond if any issues occur. I’m impressed by Valmet’s expertise and their communication with us.”

Cooperation has proved to work well: despite the difficult fuel, plant performance has been excellent. During the past four years, there have been very few unplanned shutdowns.

“Since we solved the fuel quality issue together, plant reliability and availability have been very high. Since 2017, when we started delivering steam, plant efficiency has been higher than expected,” Wegman remarks.

Text: Marjaana Lehtinen