Drammen council in Norway uses EU heat pump technology to valorise waste


14 September 2021|Views: 4817|Tags:

Drammen council in Norway uses EU heat pump technology to valorise waste

Drammen, a rural municipality in Viken, Norway, with a population of around 66,000 residents is host to one of the most innovative heat pump systems in the world. Lindum AS, a leading player in Norway in the treatment of organic waste and contaminated masses, operates the waste management facility in Drammen. The DryFiciency demonstration open loop heat pump plant, housed by Lindum at its Drammen waste processing and biogas site, has involved key DryFiciency partners Scanship and SINTEF. This makes Drammen a good showcase of European innovation actions, harnessing key expertise and investment across science and industry with the aim of directly servicing communities determined to valorise waste streams.

Converting waste into side streams

Lindum is contracted by the local Drammen council to dispose of its waste. This involves converting waste and biomass into many side streams, including pellets that can be used for renewable energy, and even biochar for composting soil. Char (which stores CO2 by a factor of three) is used by farmers not only as soil improvers but also as a carbon sink by mixing it with conventional soil in agriculture. The DryFiciency open loop heat pump system was set up as a demonstration for the purpose of steam drying various biomass feedstocks, including char.

Figure 1: Decomposed and dried char (pictured above) can act as a soil improver and as a carbon sink when mixed with conventional soil in agriculture.

Significant improvements in drying efficiency, energy savings

Scanship’s biomass drying demonstration at the Lindum waste management facility, co-ordinated by the Norwegian research organization SINTEF, is an open circuit heat pump system, also known as the Mechanical Vapour Recompression (MVR) system, which uses water as a refrigerant in steam drying processes. During this demonstration the facility underwent modifications towards achieving energy efficient Super-Heated Steam (SHS) drying. The Norwegian demonstrator shows improvements in the efficiency and capacity of the dryer of almost 70 per cent. More than 100 tonnes of biomass have so far been dried with the system. Currently, additional operating hours are required to further test the robustness of the technology. Scanship VP Innovation, Pål Jahre Nilsen, said that the system under demonstration was extremely attractive both for Scanship and Lindum, giving the companies an opportunity to further heat pump technology research and test it for valorising waste streams. “We are very eager to see the benefit of energy savings. Scanship has in the past sold hundreds of these dryers without the heat pump, but with the addition of the heat pump, now we see energy savings of potentially 65 to 70 per cent. This is massive and important,” Nilsen said. Lindum, which is the first client using this technology, is very happy with the fact that they now are drying very complicated matter in a robust way where there is proof of quality. "When they realize the full potential of the energy savings, this demonstration could be even more interesting for future clients,” he added.

The basis of innovation

As is the case in any innovative field, it is often the hitches or weaknesses during the process that provide the basis for the invention – taking a model, or a simulation from the lab and implementing it on the factory floor. SINTEF was instrumental in doing the lab simulations working in association with Scanship. SINTEF Energy Research Senior Researcher, Michael Bantle, said that one of inventive solutions that was created on the project included a paddle dryer that stirs the bio sludge, as it is processed, so that efficient drying in a superheated steam atmosphere is achieved. "The drying system is basically the evaporator of the open loop heat pump, and it is therefore important that they interact in the best thermodynamic way." Bantle explained. "This interaction is one of the main milestones! At the same time, we were able to utilize the superior properties of steam as the energy carrier, as well as the drying agent – all in one system," he said.

Figure 2: DryFiciency open loop heat pump and Scanship dryer at Lindum in Drammen, Norway


Further optimization, validation and volume throughput

Scanship’s Nilsen added that apart from the further, planned optimization and validation of the heat pump system to make it more efficient, increased volume throughput was also a major aim. He said that the next planned improvement for Scanship was to double the heat drying capacity with an additional heat exchanger, to add to the one currently in use, which could further demonstrate the capability of this technology.

Figure 3: Scanship VP Innovation, Pål Jahre Nilsen, explains how the DryFiciency open loop heat pump works.

At the Lindum site there are many different feedstocks for testing for the company’s future business, but the attractiveness of this technology goes way beyond just waste management.

Future innovations and planned hub

The Scanship innovation laboratory that was created during the project to oversee this demonstration, and other work, has been in operation for two years. During that period the lab team grew from two to fifteen people as more skills and labour were needed. Scanship is looking at the Lindum plant to act as a hub for testing various drying innovations, potentially using different compressors in the future, as well as accomplishing the task of automating the filling of the dryers, which currently is done manually. “When this is in full operation 24/7, and we can showcase this, more clients will come. Drammen has already addressed further visits to show clients the benefits of what is happening at this site because industry always will be looking for highly efficient dryers.” Nilsen concluded.