“We want to build a society independent of fossil fuels,” says Rolf Hasselström, President and CEO of Opcon AB. “Our goal is products and systems that combine minimal environmental impact with optimum performance, reliability and long life.”
“Today, a very small percentage of waste heat is recovered for energy production. We see a great potential for our waste heat-to-electricity conversion technology in the process, heavy, shipping and combined heat and power industries. Opcon’s system contributes to energy efficiency without the addition of greenhouse emissions to the environment,” continues Hasselström.
Opcon Powerbox is based on Organic Rankine Cycle (ORC) technology. Developed by Opcon Energy Systems, this technology is based on the Rankine cycle, a theoretical understanding of how steam engines work. It is named after the Scottish engineer William John Macquorn Rankine.
The Rankine, or steam, cycle converts heat into power. Heat is applied externally to a closed circuit system usually made up of a water-like fluid. Rolf Hasselström explains how Opcon’s power generation system uses the Rankine cycle principle:
“Opcon Powerbox is basically a stand-alone power plant that uses waste heat or hot water to produce steam. Excess heat may for example come from an industrial process or a marine engine. The steam drives a turbine/generator to produce electricity. The vapor is subsequently condensed back into water and pumped back to the boiler to form new steam. The core of the system is Opcon and our subsidiary SRM’s unique screw compressor technology.”
- Hasselström continues to explain the economic and environmental advantages of the Opcon Powerbox:
- The system produces electricity from excess energy (waste heat) that would otherwise be lost.
- The system uses low- and high-grade waste heat with a temperature range of between 55-250 ° C.
- Electricity production is free of new carbon emissions.
- The cost of electricity production is competitive, making the technology viable even at lower prices.
- Electricity produced from the waste heat of burning biofuels can be certified. And these certificates can be sold to electricity suppliers.
- Opcon’s technology is proven and based on unique industrial compressor know-how. It is easy to adapt the system to different types of industrial environments.
Electricity from wastewater
The Aspa mill produces bleached and unbleached kraft pulp with a production capacity of approximately 200,000 tons/year. Before the installation of the Opcon Powerbox with ORC technology, the hot wastewater was diverted into a sedimentation basin in a nearby lake. Now, this wastewater is converted to emission-free electricity at a competitive price. Furthermore, the system preheats the process water, which is also advantageous. Opcon Powerbox additionally cools the wastewater before it is finally discharged for treatment.
Opcon reduces shipping impact
Together with Wallenius Marine and with support from the Swedish Energy Agency, Opcon has developed electricity production technology based on low-grade waste heat produced in a ship’s steam and cooling systems. The goal is to save fuel while reducing emissions of carbon dioxide, nitrogen oxides, sulfur dioxide and particulates.
To this end, Opcon developed two marine versions of Opcon Powerbox:
- Opcon Powerbox WST (Wet Steam Turbine) is a special type of steam turbine that generates electricity from wet or moist steam and which does not need to be superheated – in contrast to other more conventional steam turbines.
- Opcon Powerbox ORC (Organic Rankine Cycle) enables the use of low-grade heat as a hot water source from a vessel’s cooling system. The first reference plant with both an Opcon Powerbox ORC and Opcon Powerbox WST has now been installed and tested.
Aboard the MV Figaro, the large Opcon Powerbox ORC is powered by the ship’s cooling system and delivers up to 500 kW. The smaller Opcon Powerbox WST runs on the ship’s available excess steam.
This article was published in May 2015