9 December 2011 at 1:40 am #7264
Though plans for mega-incinerator on artificial island by Shek Kwu Chau in Hong Kong look a "done deal", still worth looking at alternatives.
Emerging technology; akin to incineration but molecules are more like blasted apart at very high temperatures.
Looks very good if read proponents' info. December 2009 issue of Scientific American listed among World Changing Ideas: 20 Ways to Build a Cleaner, Healthier, Smarter World, inc:Quote:Trash is loaded with the energy trapped in its chemical bonds. Plasma gasification, a technology that has been in development for decades, could finally be ready to extract it.
In theory, the process is simple. Torches pass an electric current through a gas (often ordinary air) in a chamber to create a superheated plasma—an ionized gas with a temperature upward of 7,000 degrees Celsius, hotter than the surface of the sun. When this occurs naturally we call it lightning, and plasma gasification is literally lightning in a bottle: the plasma’s tremendous heat dissociates the molecular bonds of any garbage placed inside the chamber, converting organic compounds into syngas (a combination of carbon monoxide and hydrogen) and trapping everything else in an inert vitreous solid called slag. The syngas can be used as fuel in a turbine to generate electricity. It can also be used to create ethanol, methanol and biodiesel. The slag can be processed into materials suitable for use in construction.
In practice, the gasification idea has been unable to compete economically with traditional municipal waste processing. But the maturing technology has been coming down in cost, while energy prices have been on the rise.
Page here covers some known or potential drawbacks:
– reasons against it include that doesn't work well with wet feedstock; and especially seem more philosophical, opposed to destroying waste and not making, say, compost.Quote:Plasco’s demonstration plasma arc plant in Ottawa, Canada has been plagued with operational problems from the start in 2008, and has been unable to run at full capacity. On many occasions, emissions exceeded the maximum operational limit.Quote:
For the Ottawa project, Plasco had a “great deal of publicity” in the days leading up to a public meeting on the project, but not one person objected, he said.
While from Plasco's own website, Our Technology:Quote:
Plasco employs a patented process using plasma arc technology for the conversion of waste material into synthetic gas and marketable products. Plasco efficiently recycles heat from the process to gasify the waste and then uses the unique characteristics of plasma to refine the gaseous products into a clean, consistent syngas.
The quality of the fuel gas is highly controlled and consistent, producing fuel for a combined-cycle power plant (internal combustion engines plus heat recovery steam generators). The process also yields other valuable co-products including recyclable metal, construction aggregate, and potable quality water.
Solena Group employs plasma arc technology in several ways, including to even produce jet fuel:Quote:Solena Fuels proprietary “biomass-to-liquids” (BTL) solution encompasses three major processing blocks. The first is Solena’s proprietary high temperature, single phase gasification technology which has the ability to process heterogeneous waste feedstock with the highest efficiencies in the industry. This process produces a clean, bio-based synthetic gas (“BioSynGas”) that is then conditioned and fed into a Fischer-Tropsch (“FT”) reactor. This second FT processing block transforms the BioSynGas into renewable forms of hydrocarbons such as light FT liquids and FT wax. The third block is the upgrading of the light FT liquids and FT wax into certified, sustainable jet or marine fuel. Our design also utilizes heat and tail gases to produce electricity. Solena Fuels’ reference BTL design processes approximately 500,000 tonnes of feedstock into 16 million gallons of sustainable fuel, nine million gallons of naptha and 20MW net of exportable electricity. These offtakes are in addition to the facility producing all of its own energy to operate the facility.
– Solena has proposed building facilities here, with Cathay Pacific interested in buying the jet fuel.
Advanced Plasma Power is a UK company using plasma arc technology to create syngas for creating power or biogas. See this image, with measurements of three organic compounds, before and after gas zapped by heat and UV light at plasma arc:
Some contact made with APP, which is interested in building facilities for Hong Kong.
Westinghouse Plasma Corporation makes plasma arc units; recent orders include a unit to process 950 tonnes of waste per day, for a waste to energy plant at Tees Valley, UK.
Anaerobic digestion is the horribly unsexy term for taking organic matter such as food waste, processing with bacteria, and creating methane and other biogas, plus compost.
Excellent technique, akin to traditional ways of making compost. There were plans to make extensive use of this in Hong Kong, but so far little more than a small plant or two: apparent drawbacks include lack of local demand for compost, plus need for good waste separation. But in some places, anaerobic digestion is highly important in waste treatment, such as:
Toronto – where the Green Bin Program takes organic waste, and turns it into compost.
Greater Manchester – where waste will be separated, with organic matter treated by anaerobic digestion to produce gas for power generation, and create refuse derived fuel that can also be used for power generation.
This must be the gold standard to aim for: no waste to landfill, or to incinerate (or destroy in plasma arc facilities). Can include anaerobic digestion, but also plenty of recycling, along with reuse and – of course – reduction so there isn't much thrown away in the first place.
San Francisco had made strong progress with zero waste:Quote:Imagine a world in which nothing goes to the landfills or incinerators. We think it's achievable, and SF Environment is doing everything we can to make it happen… Today, San Francisco recovers 77 percent of the materials it discards, bringing the city ever closer to our goal of zero waste by 2020.
While we are well on our way to our diversion goals, ultimately we will need to look beyond recycling and composting to get to Zero Waste. This includes passing legislation to increase producer and consumer responsibility. In other words, manufacturers, businesses and individuals will need to be accountable for the environmental impact of the products they produce and use. There are a lot of ideas incorporated in the idea of Zero Waste.
Sadly, zero waste looks far too sophisticated for the Hong Kong government, which looks to be seeking a rather simple-minded solution to waste – aiming to make thousands of tonnes per day "disappear". But, maybe for the future, someday…
Zero Waste Alliance looks worth checking out; and even joining (open to individuals too), providing you agree with:Quote:Mission Statement
Working toward a world without waste through public education and practical application of Zero Waste principles.
- Convert waste to resources for the benefits of local production and the creation of a sustainable society.
- Redesign products and methods of production to eliminate waste by mimicking natural processes and closed-loops
- Resist incineration and land filling in order to promote innovation in resource conservation and methods of production
- Collaborate with others with common interests worldwide
See also an article from the UK: Alternatives to Incineration.6 January 2012 at 12:38 am #8680
From today's S China Morning Post:Quote:RTHK's Backchat programme on Wednesday generated a certain amount of heat with its discussion on the proposed Shek Kwu Chau incinerator project. Elvis Au was wheeled out to bat for the government . He is the assistant director of the Environmental Protection Department.
During the discussion, Au defended the decision to use old moving-grate technology, which essentially moves the material over a grate and burns it, producing a noxious fume that is vented through a chimney that, at 130 metres high, will be about half the size of the IFC 1 building. Scrubbers on the incinerator will eliminate some of the particulate matter (PM10) that are 10 micrometres in size. But it will not stop the more dangerous carcinogenic-causing particulate matter (PM2.5) which, depending on the wind direction, will add to the poor air quality in Kowloon or the Pearl River Delta. Some 1,200 tonnes of fly ash a day, complete with dioxins, will also have to be transferred to barges and dumped.
When pressed on why the government was not considering plasma arc technology, which produces considerably fewer emissions and is environmentally much cleaner, Au became somewhat cagey. He said the government had spoken to representatives from plasma arc firms, but remained unconvinced, saying the technology was untested and could only handle relatively small quantities. This does not seem to square with evidence elsewhere, which suggests that, in theory, any volume of waste can be handled by increasing the number of burners.
Despite the decision against plasma arc technology, we gather that Aecom, the government's consultants, will be visiting a plasma arc firm in Britain later this month to further inform themselves. But Aecom's counterparts in North America seem more informed. Commenting on Milwaukee's plans to proceed with a 1,200-tonne per day plant using plasma arc technology, Aecom's Mike Zebell said: "We believe that this technology is not only environmentally friendly, but ready for large-scale commercialisation."
The suspicion is that the government's reluctance to consider plasma arc technology is because it is pandering to business interests, in that the proposed incinerator plan involves significant reclamation work and contractors are already salivating at the prospect of another lucrative concrete pouring exercise.13 February 2012 at 1:38 am #8695
letter in today's S China Morning Post:Quote:We refer to the letter by Cathay Pacific (SEHK: 0293)'s biofuel manager, Jeff Ovens ("Sustainability is top priority for Cathay when looking at biofuel options", February 2).
It is interesting that he cites municipal waste – household, industrial, organic and used cooking oil – as all being suitable for conversion to jet fuel.
We support Cathay Pacific in their sustainability policy and innovative approach and see a golden opportunity for the Hong Kong government to take the lead in transforming a waste problem into a business model.
The Living Islands Movement believes that Hong Kong deserves a rethink of the government's strategy for waste management, which consists of dumping it into landfills and, when full, building one of the biggest incinerators in the world to burn our waste.
Such incinerators are old technology; more modern alternative technologies, located closer to the sources of the waste, should be considered. These do not emit poisonous dioxins, there is no toxic ash residue to be disposed of and a by-product could be jet fuel.
We urge the government not to repeat the mistakes made by Singapore, Tokyo and Beijing. A complete rethink, including a citywide reduce, reuse, recycle initiative and smarter technological solutions will result in a sustainable and healthier future for Hong Kong.
Louise Preston, Living Islands Movement23 March 2012 at 3:18 am #8707
S China Morning Post lai see column today:Quote:Don't swallow the line that an incinerator is a necessary evil
Mar 23, 2012 South China Morning Post http://www.scmp.com
On Monday, the Legislative Council panel on the environment begins listening to reports on the administration's progress on waste management, which includes an update on its plans for an incinerator on Shek Kwu Chau. This has aroused opposition from various groups objecting to the location, which is on a site of natural beauty, and the type of technology, which they fear is expensive and will add to air pollution.
There have been calls for the use of plasma arc technology, which is cleaner and produces energy that can be sold, resulting in cheaper and more efficient waste disposal.
The Environmental Protection Department insists that plasma arc is not suitable for Hong Kong, and is only used in disposing of highly toxic waste in small quantities. Yet this flies in the face of abundant evidence elsewhere.
New York recently asked for proposals for a waste-to-energy facility that specifically excluded the kind of moving grate mass burn incinerator that the EPD wants. Plasma arc technology incinerators are either in use or being built in Shanghai, Hainan, India, Britain, the US, Mexico and Japan.
Meanwhile, Imperial College London is carrying out a survey of traditional incinerators on behalf of Britain's Health Protection Agency after fears emerged over health risks, particularly for children. The study was commissioned after a high incidence of infant deaths among those living downwind from incinerators.
Another report shows people living in Detroit, the location of the world's largest incinerator, are three times as likely to be hospitalised with asthma compared with the state of Michigan as a whole. The city's asthma death rate is twice that of the state.
A study in the US shows plasma arc waste to energy projects can break even in terms of running costs when munching through 180 to 270 tonnes of municipal solid waste per day, and profitable if more waste is processed.
It seems odd that the EPD maintains the view that plasma arc can only be used for small quantities of waste while the US branch of its consultant Aecom appears to differ. "We believe that this technology is not only environmentally friendly, but ready for large-scale commercialisation," says Aecom's Mike Zebel in the US.
Why does Aecom sing a different tune in Hong Kong? Hopefully, Legco will get some answers out of the EPD and will not fall for its line that the incinerator is a necessary evil.
Looking through the papers on waste management submitted to the environmental panel, we came across one from the Hong Kong Institute of Architects. The institute's considered wisdom is that the government's proposed facility should "be a demonstration and education centre for sustainable development, incorporating sustainable lifestyle experience such as organic farming, organic food restaurant, swimming pool and spa, and education centre operated as a social enterprise". And like the proverbial rabbit in charge of the lettuce patch, it urges that "the architecture of such facility should be of the highest quality". More fuel for the incinerator perhaps?17 June 2012 at 2:07 am #8761
Science column by me for South China Morning Post (Sunday Morning Post), appears today, also posted to this site: 'Science fiction' waste solution a real option
Includes:Quote:Plasma arc incineration is a forward-looking and realistic alternative to landfills, and won't generate the toxic emissions associated with burning waste
Is this true? Can Hong Kong find no better way of dealing with waste than shipping it to a beautiful coastal area and setting fire to it? There's actually a range of alternatives, ranging from straightforward to one that seems verging on science fiction.
Plasma processes are much hotter, perhaps well over 4,000 degrees Celsius. These temperatures, coupled with intense ultraviolet light, blast molecules apart; organic chemicals disintegrate to simple components. The resulting gas mixture called syngas (synthetic gas), is mainly carbon monoxide and hydrogen. Other material forms something like lava, which can be solidified into glass-like material with metals and other toxins so effectively "locked" within that Japanese incinerators treat fly ash with plasma arc torches.
The syngas can be burned to generate electricity, rather as incinerators may be used for "waste-to-energy". But in another marked contrast to incineration, the syngas has other possible uses. One company, Solena Fuels, is working with airlines and a shipping company to develop projects that transform syngas into jet fuel and ship fuel from waste. Advanced Plasma Power, which specialises in plasma arc treatment of municipal waste, is exploring ways to synthesise natural gas.
Here in Hong Kong, the Environmental Protection Department has fielded an array of objections to plasma arc treatment.5 August 2012 at 3:43 am #8778
Guest post in Scientific American includes:Quote:Waste-to-energy is not a single technology, but a variety of technologies – both thermal and biological – that can be used to convert waste products into electricity or fuels. … waste-to-energy has such a negative connotation that cleaner technologies are also being overlooked.
A thermal technology that eliminates many of the objections to WTE is gasification…. Recent studies have shown that gasification of MSW could have substantial environmental benefits, saving 0.3 to 0.6 tons of carbon equivalent emissions per ton compared with landfill disposal.
Two other thermal technologies are plasma arc gasification and pyrolysis. Plasma gasification uses an arc of ionized gas to heat the feedstock to extremely high temperatures, breaking it down into elemental byproducts. The residual inorganic material is vitrified – turned into a glass-like substance, which is inert (non-leaching) and exceeds EPA standards. However, plasma gasification remains an expensive technology because of the energy required for the plasma arc torch. A demonstration project in Florida has received a final permit and will process 600 tons of waste per day. Notably, the facility’s permit limits for the six EPA criteria pollutants are the lowest in the country for the size of the facility.
Unfortunately, confusion over technology has led many to oppose new WTE gasification projects as incinerators in disguise, or “too good to be true.”
Non-thermal technologies use biological processes to break down waste. Anaerobic digestion, a process that employs bacterial decomposition in an oxygen-starved atmosphere, is becoming a preferred method for high-water-content animal manures as well as other waste streams.26 August 2012 at 3:05 am #8783
South China Morning Post item includes:Quote:HK team finds rich use for food waste
'Biorefinery' uses fungi to turn waste into an ingredient for making everyday products
Adrian Wan, Aug 26, 2012
A team of Hong Kong scientists say they have found a way to transform food waste into laundry detergent, plastic ingredients, and a host of everyday products, in a discovery that may ease pressure on the city's bulging landfills.
Products from the "biorefinery" could even generate income, according to team leader Dr Carol Lin, a visiting assistant professor at City University. She unveiled details of the project in the United States last week at the 244th National Meeting and Exposition of the American Chemical Society in Philadelphia.
"We are developing a new kind of biorefinery, a food biorefinery, and this concept could become very important in the future, as the world strives for greater sustainability," she said. "Our new process addresses the food waste problem by turning trash into treasure, such as detergent ingredients and bio-plastics, which can be incorporated into other useful products."
The biorefinery process involves blending food waste with a mixture of fungi that excrete enzymes to break down carbohydrates into simple sugars. The blend is fermented in a vat where bacteria convert the sugars into succinic acid. Succinic acid can be used to make a range of products – from laundry detergent to plastics and medicine.
The team received a HK$518,000 grant from Hong Kong's Innovation and Technology Commission last year, and the work is due to be completed next August.
… She has transformed food waste from CityU's cafeteria and other mixed food wastes into useful substances using the technology. The process could become commercially viable on a much larger scale with additional money from investors. "In the meantime, our next step is to … scale up the process," she said.2 December 2012 at 1:22 pm #8820Quote:
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