September, 2012:

http://www.waste-management-world.com/index/display/article-display/7429231556/articles/waste-management-world/volume-12/issue-6/features/fuel-cell-technology-gasification-game-changer.html?cmpid=EnlWMW_WTEOctober22012

Waste to Energy is increasingly attracting column inches as a potential solution to two major UK challenges: namely renewable energy production and heavy reliance on landfill. Peter Jones explores how integrating alkaline fuel cells into a WtE plant can boost net output of electricity by a minimum of 60%.

Traditionally, electrical power generation has relied on combustion. Fuel is burnt (oxidised) either producing heat to boil water for steam or directly expanding as gas, and generates enough pressure to move a piston or a turbine blade. In other words the chemical energy of the fuel is first converted to mechanical energy before it can generate electrical energy. At each of these conversion steps energy is lost, chiefly as heat. But what if you could cut out the middleman and generate electrical power directly from the fuel without using a mechanical engine and so avoiding energy losses?

This is the world of electro-chemistry and the role fuel cells play – generating electricity from chemical reactions without combustion. Batteries have traditionally occupied this space, cells of chemicals which can release electricity on demand wherever we are. This is fine for small scale applications, but a real challenge when it comes to sustained generation and megawatt scales. One contender to fill this space is the fuel cell, which has recently seen rapid development.

Origins in space

Fuel cells were first demonstrated in the 1830s, by Welshman, Sir William Grove. It took another 120 years before GE demonstrated the first commercial fuel cell application as part of the U.S. Gemini space mission. During the 1950s, English scientist Francis Bacon developed a 5 kW alkaline fuel cell for stationary power generation and the technology was licensed to Pratt and Whitney for use in the U.S. space programme.

The majority of fuel cells use hydrogen (H2) as feedstock which reacts with oxygen to form water, electricity and heat. Although the chemistry seems simple, developing fuel cells capable of sustained operation has not been trivial. Those with chemistries greater than 100 degrees centigrade are capable of producing steam as a by-product, but have to be engineered to withstand pressure and prevent surfaces becoming so hot that they become an ignition source. All of this adds to the cost of the fuel cell system. Alternatively, more recently developed fuel cell systems can operate below 100 degrees centigrade and be manufactured from low cost materials including plastics.

As the chemical reaction producing electricity is exothermic, heat can build up within the fuel cell stack. Unless controlled, this will lead to failures due to temperature gradients and thermal cycling. Some fuel cell systems use a solid electrolyte to manage this unwanted heat with blowers and heat-sink materials. However, keeping the fuel cell stack within the desired temperature range detracts from the potential efficiency of the system.

One way around this is to use a liquid electrolyte, as in the alkaline fuel cell system. This liquid electrolyte (usually potassium hydroxide) can be circulated through the fuel cell stack at the rate required carry away sufficient heat to keep the fuel cell operating at a specific temperature. Although the pump required to do this will use some of the power produced, a liquid electrolyte can also be used to transport the water produced away from the stack, where it can evaporate from the electrolyte and condense.

Another aspect requiring significant attention in the fuel itself is the hydrogen. As the smallest molecule, sealing hydrogen within the fuel cell system can be problematic. First, the system must be constructed from materials that will retain the hydrogen and not react adversely with it. Sealing the hydrogen within fuel cell systems that operate at high temperatures and pressures is an engineering challenge.

Unlocking hydrogen’s efficiency as a fuel

So where does all the hydrogen come from? Well it is the most abundant element in the universe, it is all around us. The question is how can it be unlocked efficiently to be used as a fuel? There are several methods.

The first is electrolysis of water, H2O. The chlor-alkali industry typically electrolyses brine to produce chlorine, caustic soda (NaOH) and hydrogen. This hydrogen is an excellent potential source of fuel for fuel cells and several companies are targeting this market, with global potential for more than 300 MW of power generation.Electrolysers can also be used to generate hydrogen from water using surplus electricity from renewable sources such as wind, wave and solar. One of the challenges of these forms of renewable energy is that they are intermittent – you can have too much at one time and not enough at others. By converting the surplus, low value, electricity into hydrogen there is the possibility of using it later to generate electricity with fuel cells at peak times when electricity is more valuable.

Fuel cells and waste

The second process for generating hydrogen is reforming. Here hydrogen is extracted from hydrocarbons through a chemical reaction, typically accelerated through the use of catalysts. One common process for doing this is steam methane reforming (SMR). In this process methane is reacted with steam at temperature and pressure in the presence of a catalyst, to produce hydrogen and carbon monoxide. Carbon monoxide can then be reacted with water to produce more hydrogen and carbon dioxide. Water from the fuel cell provides the majority of the water required for the production of steam in the reformer.

We could soon see the use of fuel cells with methane from anaerobic digestion technologies. Although reforming uses some of the available energy to generate hydrogen, this is more than compensated for by the efficiency of the fuel cell system, resulting in lower carbon emissions per unit of electricity generated. When the feedstock is bio-methane rather than natural gas, carbon emissions plummet. If the captured carbon dioxide can be used or stored, it could even become carbon negative.

The third source is gasification. In this process hydrocarbons are gasified to produce a synthesis gas. Municipal solid waste (MSW) or commercial waste can be gasified, usually after conversion to refuse derived fuel (RDF) by removing glass, metals and in-organics and potentially some drying and shredding. RDF typically contains plastics, papers and biological derived hydrocarbons.

In each case the synthesis gas is cleaned so that it contains predominantly hydrogen and carbon monoxide. In an additional step the carbon monoxide is reacted with water to produce more hydrogen and carbon dioxide, known as a water-gas shift reaction.

Hydrogen is separated using either a membrane or a pressure swing adsorption (PSA) unit, a device that contains an adsorbent material that will preferentially adsorb one gas from a mixture over another at pressure. As the pressure is released, only one of the gasses is evacuated from the unit. PSAs operate on a batch process.

There are few fuel cell companies targeting markets for multi-megawatt applications. One fast emerging contender is UK based AIM listed company, AFC Energy plc, which as the name suggests focuses on energy generation using alkaline fuel cells. AFC recently delivered and installed two of its commercial scale units at AkzoNobel’schlor-alkali plant in Bitterfeld, Germany.

Known as the Beta system, these units are modular, cartridge-based units which can be installed in phases. When cartridges need replacing they are simply isolated, removed and replaced, or hot-swapped, without having to be turned off. Even the fuel cell cartridges can be disassembled, the electrodes cleaned, re-coated with catalyst and reassembled.

While these systems are still at a relatively early stage of field testing, they have already been designed into several projects. One of these is Air Products’ proposed 49MW waste-to-energy plant in Teesside. Waste collected locally will be subjected to extremely high temperatures using gasification and turned into an energy-rich gas which a turbine will transform into electricity for up to 50,000 households. This technology can also produce renewable hydrogen and the facility will be the first to demonstrate Waste2Tricity’s fuel cell technology with scrap carbon derived hydrogen. This facility is one of the largest advanced gasification projects planned for the UK and signifies good progress in delivering an alternative to conventional electricity generation.

We have a looming energy gap with or without a second recession. If there is a role for the waste and fuel cell industries to fill part of that gap for efficient heat, electricity and hydrogen or fuel gases, then we must grasp the nettle and widen the horizon of our technological aspirations and delivery.

There is no doubt that the world of fuel cells is progressing more rapidly now than ever before. The drivers include higher fossil fuel prices, incentives for reducing carbon emissions, and achieving greater efficiency from fuel. All of these things will help the commercialisation of large-scale fuel cell systems for the generation of electrical power from waste, perhaps one day replacing conventional engines altogether – truly quite a revolution.

The question that remains, however, is whether local UK councils will have enough budget to replace incineration with more efficient WtE plants, harnessing technologies like advanced gasification and fuel cells and eliminating the issues of air pollution and waste ash. As this ultimately produces at least twice as much electricity for the National Grid for every tonne of waste processed, fuel cell technologies provide a great opportunity for the waste management industry.

Peter Jones is director of Ecolateral and chairman of Waste2Tricity. email: ecolateraljones@btinternet.com

Characterization of syngas produced from MSW gasification at commercial-scale ENERGOS Plants Original Research Article
Waste Management, Volume 32, Issue 10
Pages 1835-1842
G. del Alamo, A. Hart, A. Grimshaw, P. Lundstrøm

Highlights

► Gas and tars composition of syngas produced from gasification of municipal solid waste. ► Characterization of the syngas calorific value at commercial-scale Waste to Energy plants. ► Linear variation of the syngas calorific value with gasification lambda value.

Download PDF : Lufhtansa-Solena Press Rel Germany Sep 2012

http://www.nytimes.com/2012/09/11/science/plasma-gasification-raises-hopes-of-clean-energy-from-garbage.html?pagewanted=all&_moc.semityn.www&pagewanted=print

By RANDY LEONARD

David Robau tours the country promoting a system that sounds too good to be true: It devours municipal garbage, recycles metals, blasts toxic contaminants and produces electricity and usable byproducts — all with drastic reductions in emissions.

Mr. Robau, an environmental scientist for the Air Force, has been promoting a method that was developed with the Air Force to dispose of garbage with neither the harmful byproducts of conventional incineration nor the environmental impact of transporting and burying waste. It is one of several innovative techniques that the United States military has been researching to provide alternatives to the open-pit burns that some veterans of the Iraq and Afghanistan wars say have made them ill.

Already some waste companies and cities like New York have shown an interest in technology similar to what Mr. Robau has been promoting, known as plasma arc gasification. Proponents say the process can break chemical bonds and destroy medical waste, PCBs (polychlorinated biphenyls), asbestos and hydrocarbons, some of which can be hazardous if disposed of in landfills or traditional mass-burn incinerators.

Still, some environmentalists are leery. They say the ability to fully dispose of waste will discourage recycling and the development of renewable products, and the gasification will still result in toxic substances like dioxins.

Mr. Robau maintains that the process is earth-friendly. “This is not incineration,” he said. “This is gasification, so it’s a lot cleaner, a lot better for the environment.”

Mr. Robau, who also heads a nonprofit organization based in Gulf Breeze, Fla., has overseen testing of the small-scale plasma arc gasification system, which cracks complex molecules into simple elements using energy as intense as the sun’s surface, making fuel for about 350 kilowatts of electricity from about 10 tons of garbage each day, enough to run the system.

The system has been hard at work in a 6,400-square-foot building at Hurlburt Field Air Force base in Florida’s panhandle. A mechanical shredder cuts household garbage into pieces no bigger than two inches. An airtight auger feeds the waste into an oxygen-poor gasification chamber, where temperatures reach more than 9,000 degrees.

In an instant, wood disintegrates, plastics turn to gas. Bits of metal and glass fall into a molten pool.

From two graphite electrodes, an arc of electricity leaps about a foot to the molten slag, producing a cloud of ionized particles known as plasma, which heats the chamber. Most heavier metals settle to the bottom of the pool, below a layer of liquid silica and other oxides. The metals are removed, cooled and used for steel or other products.

“Effectively, 100 percent of all the metals on the base are being recycled,” Mr. Robau said.

The liquid oxides are removed and form a glassy solid when cooled. The slag traps contaminants like errant lead molecules and other heavy metals in a vitreous matrix that takes up 1 percent of the volume of the original waste, Mr. Robau said, a tenth of the volume left over after traditional incineration.

The vitrified component meets standards for disposal and may even be suitable for use as a construction aggregate, according to Mr. Robauand other industry professionals.

In the chamber, organic gases break down into hydrogen and carbon monoxide — the components of a fuel called synthesis gas, or syngas — which exits the furnace.

The gas passes through a plasma torch polisher, which breaks down remaining complex molecules and soot.

Injected water cools the syngas to less than 200 degrees. The extreme temperature of the plasma followed by quick cooling inhibits the formation of dioxins and furans (another organic compound), according to Mr. Robau and other industry experts.

The lack of dioxin creation would be a benefit over traditional incinerators and other types of gasifiers, in which lower temperatures and incomplete burning result in toxic compounds.

Emissions rules forced a 99 percent cut in dioxin and furan emissions and a 96 percent reduction in mercury from traditional incinerators between 1990 and 2005, according to the Environmental Protection Agency. However, companies have to dispose of the toxic ash filtered from mass-burn facilities.

After water quenches the gas in the Hurlburt system, stripping processes produce sodium bisulfate and hydrochloric acid, which can be sold, Mr. Robau said.

The gas passes through three types of filters to catch remaining impurities. The resulting syngas is as clean or cleaner than natural gas, and the system produces less than half the nitrogen oxides and 5 percent of the sulfur oxides and mercury of a traditional incinerator, Mr. Robau said. The Air Force uses the syngas to produce enough electricity to power the system.

Companies have used plasma arc technology in steel refining for more than a century. Some small-scale plasma gasifiers are specialized to process materials like asbestos or medical waste.

In Japan, a plasma facility originally designed to zap residue from automobile shredding now handles up to 150 tons of municipal solid waste each day in the city of Utashinai. And construction on a plant of similar size, designed to process industrial waste and wood chips, wrapped up this summer in Morcenx, in southern France.

Companies have been eying plasma gasification of municipal waste with eager hopes, but until recently financing has lagged. Plasma facilities are expensive, and the energy-hungry arcs and torches can consume half of the generated electricity. On the other hand, the systems can also handle medical and hazardous waste, which can command two to four times the fees associated with municipal waste.

“The problem has been over the years trying to find that economic sweet spot,” said Joe Vaillancourt, who evaluates newer technologies for Waste Management, a $15.4 billion company with headquarters in Texas.

In the past five years, with increased interest in energy independence and sustainability, venture capitalists and companies have financed testing of small-scale systems, including a 25-ton system built and run by InEnTec in Arlington, Ore., Mr. Vaillancourt said. Waste Management now holds an equity stake in InEnTec.

Last month the Agriculture Department announced a conditional $105 million loan guarantee for Fulcrum BioEnergy to build a much larger system outside Reno, Nev. It will use three InEnTec plasma melters to process 400 tons of garbage a day, an unprecedented scale for a plasma municipal waste facility, said Mr. Vaillancourt and others in the industry. Fulcrum plans to create ethanol from the syngas, and expects the Reno plant to be running in 2014.

New York City, too, is looking for innovative technology to deal with some of the city’s waste. In March, the Bloomberg administration requested proposals to build a facility that would use newer techniques like plasma gasification or anaerobic digestion to process as much as 900 tons of garbage a day.

“New Yorkers want their trash to be handled in an environmentally friendly way,” said Caswell F. Holloway, deputy mayor for operations. “Anything would be better than putting it in the ground.” The city is reviewing the proposals.

Still, some environmental groups, like the Sierra Club and the Global Alliance for Incinerator Alternatives, lump these techniques in with traditional incinerators, claiming that they still produce dioxin. They also oppose renewable energy credits for these facilities.

Allen Hershkowitz, a scientist with the Natural Resources Defense Council, said he believed there was a place for waste-to-energy operations, but only after recycling and composting programs had been maximized.

He said he still believed that communities could reach recycling rates of 60 to 70 percent. In his view it is premature for a city like New York, with a recycling rate of about 15 percent, to be considering setting up a new waste facility. “They’re not even at the point where they should be thinking about waste-to-energy,” Mr. Hershkowitz said.

This article has been revised to reflect the following correction:

Correction: September 12, 2012

An article on Tuesday about the plasma arc gasification method of waste disposal misstated part of the name of the organization with which Allen Hershkowitz, a scientist who said he believed that New York City’s low recycling rate makes its interest in waste-to-energy technology premature, is affiliated. Mr. Hershkowitz is with the Natural Resources Defense Council, not the National Resources Defense Council.

http://www.letsrecycle.com/news/latest-news/energy/councils-need-certainty-from-efw-technology

11 September 2012

§  Energy

By Steve Eminton

Developers of gasification facilities for waste need to prove themselves over the next few years, Defra’s senior energy from waste official said today.

The comment came from the department for environment’s policy lead, Dr James Cooper, who was speaking after a presentation by his Defra colleague, Richard Pullen, head of waste strategy and regulation at the RWM Conference in Birmingham this morning (September 11).

“The government’s energy from waste policy has been driven by the need to divert material from landfill to meet landfill diversion targets so we have tended to go for mass burn.”Dr Cooper explained that there was a “subtle key phrase” in last year’s waste review which indicated a change in view over energy from waste.

Now, he said the waste review had referred to the aim of getting more energy out of waste with the idea of using more “up the pipe” solutions.

Dr Cooper explained that the department recognised there would also be less waste available with minimisation policies and more recycling.

Reliability

It would be important for local authorities, he said, to see gasification and other projects as reliable. “We have to get enough working on the ground to scale so that local authorities when procuring their contracts know the technology will work. Local authorities are concerned, they want that degree of reliability.”

And, he added that there would be local authorities which will be looking to procure infrastructure in the next few years. “Some of these started 20 years ago and when they come up for renewal they will be looking for the best infrastructure available at the time.”

Dr Cooper highlighted projects of note in terms of new technologies for energy from waste. The first is the GreenSky gasification project in Essex being developed with British Airways and the second is an Air Products facility on Teesside.

Earlier Richard Pullen of Defra had spoken of the need to ensure that future waste policy is capable of clear and fair implementation.

He also highlighted that the department wanted to promote the waste and resource sector’s contribution to economic growth.

By RANDY LEONARD
Published: September 11, 2012

PyroGenesis Canada
GARBAGE IN, ENERGY OUT A plasma arc gasification system at the Hurlburt Field Air Force base in Florida processes 10 tons of garbage a day, making enough energy to sustain the system.

David Robau tours the country promoting a system that sounds too good to be true: It devours municipal garbage, recycles metals, blasts toxic contaminants and produces electricity and usable byproducts — all with drastic reductions in emissions.

Mr. Robau, an environmental scientist for the Air Force, has been promoting a method that was developed with the Air Force to dispose of garbage with neither the harmful byproducts of conventional incineration nor the environmental impact of transporting and burying waste. It is one of several innovative techniques that the United States military has been researching to provide alternatives to the open-pit burns that some veterans of the Iraq and Afghanistan wars say have made them ill.

Already some waste companies and cities like New York have shown an interest in technology similar to what Mr. Robau has been promoting, known as plasma arc gasification. Proponents say the process can break chemical bonds and destroy medical waste, PCBs (polychlorinated biphenyls), asbestos and hydrocarbons, some of which can be hazardous if disposed of in landfills or traditional mass-burn incinerators.

Still, some environmentalists are leery. They say the ability to fully dispose of waste will discourage recycling and the development of renewable products, and the gasification will still result in toxic substances like dioxins.

Mr. Robau maintains that the process is earth-friendly. “This is not incineration,” he said. “This is gasification, so it’s a lot cleaner, a lot better for the environment.”

Mr. Robau, who also heads a nonprofit organization based in Gulf Breeze, Fla., has overseen testing of the small-scale plasma arc gasification system, which cracks complex molecules into simple elements using energy as intense as the sun’s surface, making fuel for about 350 kilowatts of electricity from about 10 tons of garbage each day, enough to run the system.

The system has been hard at work in a 6,400-square-foot building at Hurlburt Field Air Force base in Florida’s panhandle. A mechanical shredder cuts household garbage into pieces no bigger than two inches. An airtight auger feeds the waste into an oxygen-poor gasification chamber, where temperatures reach more than 9,000 degrees.

In an instant, wood disintegrates, plastics turn to gas. Bits of metal and glass fall into a molten pool.

From two graphite electrodes, an arc of electricity leaps about a foot to the molten slag, producing a cloud of ionized particles known as plasma, which heats the chamber. Most heavier metals settle to the bottom of the pool, below a layer of liquid silica and other oxides. The metals are removed, cooled and used for steel or other products.

“Effectively, 100 percent of all the metals on the base are being recycled,” Mr. Robau said.

The liquid oxides are removed and form a glassy solid when cooled. The slag traps contaminants like errant lead molecules and other heavy metals in a vitreous matrix that takes up 1 percent of the volume of the original waste, Mr. Robau said, a tenth of the volume left over after traditional incineration.

The vitrified component meets standards for disposal and may even be suitable for use as a construction aggregate, according to Mr. Robau and other industry professionals.

In the chamber, organic gases break down into hydrogen and carbon monoxide — the components of a fuel called synthesis gas, or syngas — which exits the furnace.

The gas passes through a plasma torch polisher, which breaks down remaining complex molecules and soot.

Injected water cools the syngas to less than 200 degrees. The extreme temperature of the plasma followed by quick cooling inhibits the formation of dioxins and furans (another organic compound), according to Mr. Robau and other industry experts.

The lack of dioxin creation would be a benefit over traditional incinerators and other types of gasifiers, in which lower temperatures and incomplete burning result in toxic compounds.

Emissions rules forced a 99 percent cut in dioxin and furan emissions and a 96 percent reduction in mercury from traditional incinerators between 1990 and 2005, according to the Environmental Protection Agency. However, companies have to dispose of the toxic ash filtered from mass-burn facilities.

After water quenches the gas in the Hurlburt system, stripping processes produce sodium bisulfate and hydrochloric acid, which can be sold, Mr. Robau said.

The gas passes through three types of filters to catch remaining impurities. The resulting syngas is as clean or cleaner than natural gas, and the system produces less than half the nitrogen oxides and 5 percent of the sulfur oxides and mercury of a traditional incinerator, Mr. Robau said. The Air Force uses the syngas to produce enough electricity to power the system.

Companies have used plasma arc technology in steel refining for more than a century. Some small-scale plasma gasifiers are specialized to process materials like asbestos or medical waste.

In Japan, a plasma facility originally designed to zap residue from automobile shredding now handles up to 150 tons of municipal solid waste each day in the city of Utashinai. And construction on a plant of similar size, designed to process industrial waste and wood chips, wrapped up this summer in Morcenx, in southern France.

Companies have been eying plasma gasification of municipal waste with eager hopes, but until recently financing has lagged. Plasma facilities are expensive, and the energy-hungry arcs and torches can consume half of the generated electricity. On the other hand, the systems can also handle medical and hazardous waste, which can command two to four times the fees associated with municipal waste.

“The problem has been over the years trying to find that economic sweet spot,” said Joe Vaillancourt, who evaluates newer technologies for Waste Management, a $15.4 billion company with headquarters in Texas.

In the past five years, with increased interest in energy independence and sustainability, venture capitalists and companies have financed testing of small-scale systems, including a 25-ton system built and run by InEnTec in Arlington, Ore., Mr. Vaillancourt said. Waste Management now holds an equity stake in InEnTec.

Last month the Agriculture Department announced a conditional $105 million loan guarantee for Fulcrum BioEnergy to build a much larger system outside Reno, Nev. It will use three InEnTec plasma melters to process 400 tons of garbage a day, an unprecedented scale for a plasma municipal waste facility, said Mr. Vaillancourt and others in the industry. Fulcrum plans to create ethanol from the syngas, and expects the Reno plant to be running in 2014.

New York City, too, is looking for innovative technology to deal with some of the city’s waste. In March, the Bloomberg administration requested proposals to build a facility that would use newer techniques like plasma gasification or anaerobic digestion to process as much as 900 tons of garbage a day.

“New Yorkers want their trash to be handled in an environmentally friendly way,” said Caswell F. Holloway, deputy mayor for operations. “Anything would be better than putting it in the ground.” The city is reviewing the proposals.

Still, some environmental groups, like the Sierra Club and the Global Alliance for Incinerator Alternatives, lump these techniques in with traditional incinerators, claiming that they still produce dioxin. They also oppose renewable energy credits for these facilities.

Allen Hershkowitz, a scientist with the Natural Resources Defense Council, said he believed there was a place for waste-to-energy operations, but only after recycling and composting programs had been maximized.

He said he still believed that communities could reach recycling rates of 60 to 70 percent. In his view it is premature for a city like New York, with a recycling rate of about 15 percent, to be considering setting up a new waste facility. “They’re not even at the point where they should be thinking about waste-to-energy,” Mr. Hershkowitz said.

This article has been revised to reflect the following correction:

Correction: September 11, 2012

An earlier version of this article misstated the name of the organization with which Allen Hershkowitz is affiliated. He is a scientist with the Natural Resources Defense Council, not the National Resources Defense Council.

http://www.nytimes.com/2012/09/11/science/plasma-gasification-raises-hopes-of-clean-energy-from-garbage.html?hpw&pagewanted=all