Waste-to-Energy
Gasplasma®: Revolutionizing the Waste-to-Energy Landscape
“The critical status of waste management capability, coupled with the urgent need to develop sustainable energy sources, has opened the door to the opportunity for waste-to-energy technologies to take center stage.
Rolf Stein
Waste management remains a critical issue in the UK and Europe. Each year Europe produces around 3 billion tons of waste — equivalent to 6 tons per person. Currently, 67 percent is either sent to landfill or incinerated. Neither of these solutions is an ideal means of dealing with waste and there is a pressing need to develop and deploy more effective and efficient waste management technologies as alternative solutions. Much of the emphasis to date has been on producing less waste in terms of recycling more and consuming less. While this target should be strongly supported, in order to encourage more sustainable consumption patterns for the future, recycling cannot solve the whole problem, especially as Europe’s population continues to rise at a rapid pace.
At the same time, the landscape for energy generation in the UK and elsewhere is shifting. With carbon-heavy, exhaustible fossil fuels generally in decline, the hunt is on for efficient, clean, consistent energy sources that can fill the gap. The government has ambitious renewable energy targets to be met, with 15 percent of all energy to come from renewable sources by 2020 and CO2 emissions to be cut by 34 percent from 1990 levels by 2020 and by 80 percent by 2050. Europe also looks set to legislate for binding emission reduction targets.
There is increasing recognition amongst policymakers of the need to promote innovation in renewable technology development. For example, there is a growing awareness of innovative advanced conversion waste-to-energy technologies that can generate an efficient, consistent energy supply while also contributing to the UK’s and Europe’s vision for a zero waste economy. The potential for waste to be treated as a resource is an opportunity that needs to be realized, especially when the requirement for effective and sustainable waste management solutions has never been greater.
The Gasplasma®Process
One such solution is Gasplasma. The core Gasplasma technology is a two-stage advanced conversion technology. It combines two long standing and well proven technologies (gasification and plasma conversion) in a unique configuration to convert municipal and commercial waste into a clean, hydrogen-rich synthesis gas (syngas) and a vitrified recyclate product called Plasmarok®, which can be used as a high value construction material.
A full Gasplasma plant comprises four main sections: 1) a waste reception hall and materials recycling facility (MRF); 2) the core Gasplasma technology consisting of the Fluidized Bed Gasifier and Plasma Convertor; 3) gas cleaning equipment to cool, clean and condition the syngas; and 4) a Power Island to generate renewable power and recover residual heat.
The waste reception hall can typically accept 150,000 ton of municipal solid or commercial and industrial waste per year. The waste is first sifted to remove any oversized objects. The remainder is then put through a MRF to recover any metals, glass and hard plastics, before the residue is shredded and dried to make around 90,000 tons of refuse derived fuel per year.
The next stage comprises a Fluidized Bed Gasifier that transforms the organic materials in the refuse derived fuel into a crude or unrefined syngas; this is done at a temperature of around 800oC in a controlled reduced oxygen environment. The syngas produced by gasification contains condensable tars making it unsuitable for use in efficient gas engines or gas turbines.
The crude syngas is then passed into a separate, secondary Plasma Converter. The intense heat from the plasma arc—in excess of 8,000oC—and the strong ultraviolet light of the plasma ‘cracks’ the condensable tars and other longer chain organics into a clean hydrogen-rich syngas. The bottom ash from the gasifier, containing mainly inorganic elements, is vitrified into a product called Plasmarok®. This is a mechanically strong and extremely leach resistant material with multiple applications (in contrast to the bottom ash arising from other thermal waste processes).
The syngas is then cooled, cleaned and conditioned through conventional wet and dry scrubbers (to remove any acidic components) before being used directly in a Power Island, consisting of reciprocating gas engines or gas turbines, to generate renewable power, which can be fed directly into the electricity grid. Residual heat is also recovered from the process to be used in CHP mode within the plant itself as well as for other users in the vicinity.
Key Benefits
The Gasplasma process has a number of advantages from an environmental, social and economic perspective. Environmentally, the process delivers high overall energy efficiency, maximum combined heat and power potential, minimal generation of secondary residues and very low plant emissions. Further, the process produces a high value construction material called Plasmarok® that is recognized as a product not a waste. This removes any environmental, regulatory and commercial risk stemming from concerns over the eco-toxicity of bottom ash.
The Gasplasma process facilitates resource optimization as it enables almost complete landfill diversion and is complementary to recycling. The process can be used in conjunction with existing recycling schemes, as it takes waste that cannot be recycled and uses it to produce energy; thus maximizing the use of waste as a resource.
From a social perspective, a full-scale Gasplasma plant is around 15m high, meaning that it can fit into a standard warehouse similar to the kind used for out of town business parks. This means a plant can be located, unobtrusively, on the edge of a town, taking waste from that town and supplying power and heat in return—a local, community solution to local waste management challenges and sustainable energy requirements. This can all be achieved at a cost that compares very favorably with other thermal waste treatment technologies, especially on a lifecycle analysis basis.
Widespread Applications
The two products from the process, the energy-rich syngas and the Plasmarok have a variety of end uses making the technology very flexible. The syngas can be used to generate electricity directly and efficiently in gas engines or gas turbines. As fuel cell technology advances rapidly, the syngas will be capable of being used commercially in fuel cells, thereby further improving electrical generation efficiency. Alternatively, the syngas can be processed into synthetic natural gas (SNG) for distribution in existing gas grids or into hydrogen or liquid fuels.
Landfill Mining: A New Concept
The concept of recuperating a landfill site opens up a whole spectrum of opportunities especially as our primary sources of materials and fuels become ever more depleted. Furthermore the sites themselves, around which in many cases populations have grown, can be returned to developable land or parkland with amenity value (see Landfill Mining in Action sidebar). There is huge potential for the concept of landfill mining to be applied in the UK, with 2 billion tons of waste sitting in landfill sites around the country. The potential to claim back large areas of developable land is also significant.
A Real Opportunity
The critical status of our country’s waste management capability, coupled with the urgent need to develop sustainable energy sources, has opened the door to the opportunity for waste-to-energy technologies to take center stage. The efficiency, key benefits and rationale that underpin processes such as Gasplasma® mean that there is a real opportunity for the UK to work towards a zero waste economy while delivering on renewable energy generation targets.
Rolf Stein is CEO of Advanced Plasma Power, Swindon, UK. He has worked in the plasma industry since 2006. Prior to his appointment as CEO of APP, he was COO for the company. He joined APP as Commercial Director with a particular focus on securing and commercializing the company’s intellectual property portfolio. Before working in this industry, Rolf had extensive international experience holding senior positions in large multi-national technology companies including Hewlett Packard and Apple. For more information on APP, contactKate Colclough, Marketing Manager, at [email protected] or visit www.advancedplasmapower.com.
Sidebar
Landfill Mining in Action
Advanced Plasma Power (APP) is putting this very concept into action at the landfill site of Remo Milieubeheer NV in Houthalen-Hechteren, Belgium, where APP and global waste management firm Group Machiels have embarked on a pioneering project to convert some 16 million tons of landfilled waste into recyclables and clean energy. In the period of reclamation, the waste will be processed through APP’s Gasplasma plants, producing power for the local community and heat for nearby greenhouses to grow vegetables.