35 years in recycling and energy recycling

In 1979 the company “Svenska Slipers” (Swedish Sleepers) were founded by Thomas and Jill Karlström. Their idea was to take care of the wooden sleepers that were used (and still is) as crossties under the iron rails. The sleepers would then be sold to gardens, golf courses and other facilities in Sweden in need of this build material. It turned out to be a good idea.

After only a few years however it was soon found that not all sleepers could be used in this way, they were old, broken and ugly after having been in the tracks for more than 30 years. We then started to investigate if it would be possible to energy recycle these bad wooden sleepers. This then lead to a debate about creosote (the most common impregnation compound used to preserve the wooden sleepers) and whether or not it was hazardous to incinerate.

This phase in the company history was surrounded by vast studies on creosote and what happens when combusting this hydrocarbon. The studies showed that there was no hazard connected to the incineration of creosote given the correct combustion in the right temperatures (modern industrial furnaces). In fact, there is more hazard in grilled (burnt) meat than in creosote. But since creosote is a compound that should not leak into the ground a decision was taken not to allow any further sale to the market. Our standpoint was old sleepers should not be used for anything else than what they were intended for from the beginning, that is in railroad tracks, and that they therefore should be energy recycled at “end of life”.

We advocated this line for many years and the well expanded thermal heating net of Sweden gave us advantages towards the competition for many years. As with many types of waste it is still more environmentally friendly to ship it here (Sweden) than to leave it “half heat recovered” somewhere else.

The amounts of sleepers than now reached our gates in Trollhättan started to put pressure on our equipment for fuel preparation (crushers etc.). We started testing different equipment (as many of you do today) and we ended up developing a system allowing high capacity and low wear.

The concept was the Hammer Mill concept, later called the FlexHammer™ System, our main product today. It became more and more attractive to look into other types of wooden waste materials. We expanded by acquiring a 12 MWth heating plant. This gave us further advantages in the market place.

In order to pass the “new” 2005 rules on combustion (EU) the boiler needed to be re-constructed (re-built). The chemists and technicians that was previously involved in the creosote investigations now helped us develop a two stage burning technology (gasification) that is now one of our products complying with the waste directive for incineration in the EU.

This product is relatively new for us but it has shown that it will be a concept that sticks around. Now, 2016 we (IQR) focus on transferring the knowledge we built up during the years to companies in similar situations today. We know what it takes to be sustainable in energy recovery from waste materials. We are proud over the fact that so many of our employees has been with us for so long, making it possible for us to keep up and on top of the times ahead.

Pronar - Slow Speed/ Two Shaft Machines