The entire year led to record-breaking energy production

In 2017, Westenergy had no need for any major repair work, and we managed to produce more energy than expected. Due to the skilled operating staff and maintenance team, even demanding situations were quickly and safely resolved.

Production Manager Kai Alavillamo, Maintenance Manager Rauno Tuokkola and Operating Engineer Petri Suomela have all worked at Westenergy since the plant started operations in 2012. Over the years, these men have seen a variety of challenging situations. Year 2017, however, passed excellently.

– At the production site, last year was very good, both in terms of the utilisation rate and delivered energy. Our figures were record-breaking and, for the first time in five years, we managed to complete a good year without any major repairs. Improvements made in 2016 were also seen in energy production, says Kai, who is responsible for production.

Successful maintenance shutdowns

In previous years, Westenergy’s utilisation rate was hampered by the refractory lining of the furnace, which was completely replaced by a new Inconel boiler pipe structure. Last year, we stayed within the maintenance budget and even below it. The total shutdown time was 16 days as planned.

– A four-day shutdown was held in the spring and a regular annual 11-day maintenance shutdown was held in the autumn. As part of the annual maintenance, we made periodic inspections of the pressure equipment, which must be done every four years. In the spring, we repaired leakages in the waste feeding hoppers, recalls Rauno, who designs and is responsible for maintenance operations.

At the waste incineration plant, the most critical moments for the maintenance are production ramp-downs and ramp-ups. Last year, everything went according to plan.

– Routines are important. Production ramp-downs and ramp-ups are special situations that only occur a few times a year. It is therefore important that they are done in accordance with the manufacturer’s instructions. The ramping-down of the plant takes about 12 hours, as the waste continues to burn on the grate for a few hours after the waste feeding has stopped. A ramp-up after a service shutdown is a more challenging situation, because we need to be certain that all the equipment will start and function properly. Sometimes something happens unexpectedly. Fortunately, we have experienced operating and maintenance staff, says Petri, who is responsible for the operating staff’s work.

Waste quality has a direct link to emissions and efficiency

Westenergy’s operations are directly affected by the quality of the waste, which depends on what people throw in their bins daily. As a fuel, waste can vary a lot. In summer, the waste is drier, so its calorific value is better. In the autumn and winter, the waste is more wet, so the calorific value is worse. Also, the share of metal among Westenergy’s waste is still high.

– In 2017, the landfill ban was also seen in waste quality: the quality deteriorated clearly and the amount of PVC and gypsum among the incinerated waste grew for example. This caused considerable strain on the flue gas cleaning system. However, the waste directs the company’s operations and operational goals, which, despite the challenges, are quite high, says Kai.

Westenergy is planning to purchase a flue gas scrubber to achieve even more stringent emission limits in the future. On the other hand, the flue gas scrubber also enables significant energy recovery, which can be utilised in district heating production. Technical and financial studies related to the acquisition took place last year so that the procurement project can be started as soon as it is authorised:

-We have invited tenders for the scrubber, so we can start a procurement project as soon as we get the permission. We have also made some technical studies, including installation sites, condensates and the location of the flue gas stack, reveals Rauno.

In 2017, Westenergy had no need for any major repair work, and we managed to produce more energy than expected.

A good pace for next year

The men expect 2018 to be the same as the previous year; the goal is to keep the plant production and utilisation at a high level. Westenergy also aims to incinerate 185,000 tonnes of waste during 2018. This amount includes waste in interim storage that was accumulated during the major service shutdowns and repair work of 2015 and 2016.

Hats off to the operating and maintenance staff

Last year, Westenergy again faced some alarming situations stemming from the wrong waste ending up on the grate. Sometimes, we at the plant wonder a lot, why people throw these kinds of items into their bins. There are, for example, cardboard bales and transformers.

– One item of waste that caused problems at the facility was a trellising full of hooks from a greenhouse. The twine itself is a good material for burning, but its hundreds and thousands of hooks had gathered the twine into a ball that first jammed the feeding hopper before suddenly falling on the grate. There it burned so fiercely that it began to vaporise as it was being cooled and it eventually broke the equipment. We tried to remove the twine ball with a special tool, but that also ended up in the hopper, laughs Kai and continues:

– You really have to lift your hat to the operating and maintenance staff. Threats to the plant remain low due to their rapid and competent actions. Last year, there were many problematic situations that could have taken several days to solve. The operating staff ‘s rapid actions helped us achieve our goals.