Nevel Oy’s (ex-Vapo Oy) Karkkila heating plant has been producing district heating for its hometown residents and other properties since 1991. The heating plant previously used peat as fuel, in addition to which biomass was introduced in 2019. Laitex identified and implemented the necessary changes to the fuel feeding system. “The renewed conveying equipment has been in use for a year, and there has been no problems,” says Aleksi Kraft, Maintenance Manager at Nevel Oy.
The introduction of the new fuel mixture affected the plant’s boiler output. The calorific value of biomass is lower than peat and the quality of the mixture may vary. The plant’s goal was to produce 8 MW, but with the new mixture the output was often 5 MW. “I called Laitex’s Timo Kupsanen and arranged a visit on site to investigate the problem,” Kraft says.
With a small change, a large effect on the plant’s efficiency
A bottleneck limiting the boilers power was found in the feed equipment through which more material had to be transported. The conveyor system could have been changed in several different ways. “We wanted to implement the change as agilely and cost-effectively as possible – a big renovation doesn’t always have to be done when the change is done right. In this way, the renovation pays for itself quickly and the investment remains small in relation to the benefits obtained,” says Kupsanen.
“Of all the options proposed to us, Laitex had the most functional package in terms of schedule, implementation and price. The drive arrangement can also be counted in their favour,” Kraft says.
The change was implemented by replacing the boiler’s feeding screw, gearbox and motor. In addition, Laitex installed the hardware and made changes to the service platform to get the assembly in place. “When the entire conveyor did not have to be replaced, the factory premises did not require changes and the plant downtime was minimized,” Kupsanen continues.
The conveyor upgrade improved the capacity of the entire plant
Kraft is pleased with the professionalism of Laitex’s team and the implementation of even the smallest details during the project. “Laitex has a good and expert service: they have good equipment technical knowledge. They understand the boiler plant as a whole and they know exactly the challenges of both fuel feeding and ash handling and the solutions to them. They serve the customer’s needs well,” he praises.
“Laitex was also involved in the commissioning, where it was found that something was wrong – as is often the case during test runs. Although the repair work was not very small, it was done quickly. So we got just the kind of turnkey package we were expecting,” says Kraft. Now the boiler can produce more than 8 MW without additional energy production. “The biggest advantage for us is that the efficiency of the plant has improved. We have had minimized repair costs and through direct efficiency we have received direct financial benefits, ”says Kraft.
Renewal of Nevel Oy’s Karkkila heating plant’s fuel mix is related to the government’s goal of carbon-neutral Finland in 2035. From Laitex you will find expertise in developing the entire heating plant’s processes, from biomass transport to combustion waste disposal. When your heating plant needs an upgrade to conveyor systems or ash handling automation, give us a call.