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Here's how it works. First, bulk metals are removed, and the rest of the shredded waste is conveyed to a 700 ºC gasification chamber. Most of it volatilizes to a complex blend of gases and rises toward a plasma torch operating at 1200 ºC--well below the 3000 to 5000 ºC used with hazardous wastes. The plasma reduces the complex blend to a few simple gases, such as steam, carbon monoxide, and hydrogen, plus assorted contaminants such as mercury and sulfur; subsequent cleanup systems remove the steam and mercury and scrub out the soot before the syngas is sent to an internal combustion engine generator.
The waste that doesn't volatilize forms a solid slag and drops to the bottom of the gasification chamber. The slag is then pushed to another plasma torch, which drives off remaining carbon in the slag before the slag is cooled and vitrifies. The resulting glass can be blended into asphalt road surfacing or cement.
Under its deal with Ottawa, PlascoEnergy will cover the estimated $125 million that it takes to build the plant, which could be operating within three years, while the city will pay only standard tipping fees--on the order of $60 per metric ton.
Ze-gen plans to avoid the challenge of handling complex municipal wastes by focusing first on an easier-to-handle feedstock: construction and demolition wood wastes. The company has filed seven patents on its molten metal gasification technology and waste-to-syngas process, but the equipment itself is standard for the steel industry, which uses molten iron to catalytically drive off impurities from ore. Ze-gen's pilot plant processes wood waste using a standard electrically heated steel-industry crucible full of molten iron.
Ze-gen CEO Bill Davis estimates that a full-size plant just slightly bigger than PlascoEnergy's commercial plant will produce enough syngas to create 30 megawatts of electricity, but he says that the syngas is also of sufficient quality to be used in other applications. As examples, he cites synthetic gasoline, diesel production, and refinery applications.
A versatile new process for making biofuels could slash their cost.
Researchers have built and tested for the military a portable machine that efficiently turns waste into electricity.
A portable plant might make it economical to transform huge amounts of logging "waste" into energy -- right in the forest.
A problem with air-blown gasification is that the syn gas is diluted with N2, so the fuel value of the gas is significantly degraded. Is there a similar problem with plasma-torch gasification? Seems like the torch needs some gas, which won't be contributing to the fuel value.
Efficiency of Biogas-Digesters
Regarding the issue of energy from waste: Does anybody know studies about the input/output ratio of small biodigesters which are feed with animal manure or human excrements?
Are there any cutting edge solutions to enhance the efficiency of Biogas-Digesters? (e.g. bacteria, catalyst)
Re: Efficiency of Biogas-Digesters
The Ann Arbor MI landfill is currently using sewage effluent to generate methane from decomposition of the landfill. I'll try to find out more for you but this may demonstrate that it is feasible. The Bates Auto gas convertor was made using Chicken Poop n straw in a heated reactor 80-90 ' F for enough gas to power a car up to 75 mph, by a british entrepaneur, The new Alchemy institute had a slide show on Methane powered power plants from waste, and home applied systems that showed bamboo piping and wax for fittings. etc Good luck. Let me know of ant results. I'm tryiong to build a 10 step outhouse that has a methane decomposer and collection system. Something similar to the Leslie Sciece Centers (Ann Arbor) composting toilets.
this is a much more sensible approach than dedicating one food crop to ethanol production and it simultaneously solves the landfill and mercury-producing issues of other trash-to-energy technologies. with the additional ability to convert waste cellulose such as grass clippings, brush and shrubbery, it doesn't take food away from a population and the ridiculous pressure on corn crops and its resultant exorbitant pricing and soil nutrient depletion will no longer exist. plus, there's an exponentially greater amount of non-edible greenery and waste that can actually sustain the demand for fuel burning until solar bypasses even this necessity, being an even cleaner alternative for many mobile, as well as stationary large-scale applications.
This technique also provides other resources than just syngas and slag. The process also generates potable water, commercial salt, and sulfur fertilizer (check there website). Thats 5 different products coming out of each tonne of waste we feed this process. Building around 1300 of these at a cost of around 180 billion (of the 400-tonne/day size plants) and distributing them throughout the US, we could essentially eliminate all trash generated on a daily basis and use all of the byproducts generated from it to supplement our growing need for electricity, building material, water, salt (not so much), and fertilizer. I think this technology is amazing and could solve lots of problems. It is surely better than landfills. Feel speed ahead Plasco!!!
The article entitled “Garbage In, Megawatts Out” appeared on July 02 in the MIT Technology Review reporting that the city of Ottawa, Ontario had approved a gasification facility that would use 400 metric tons/day (equal to 880 US tons) to produce 21 megawatts of electricity. Before this is hailed as a breakthrough for turning waste into energy, it deserves further scrutiny. It must be compared with recycling on the basis of the energy produced, effects on the environment, and the economy.
• Energy—Using the energy content of the waste consumed, the efficiency of the Ottawa facility can be calculated to be below 20%. For each ton of material used for fuel, another ton must be produced from virgin materials to replace it. The US EPA has supplied data on the energy required to produce a ton of each constituent of municipal solid waste from both virgin and recycled materials. The energy saved by recycling is three to five times that produced using waste as a fuel. Recycling the materials instead of using them as fuels saves more than the “megawatts out” even if the thermodynamic limit for energy efficiency could be achieved.
• Environment—Producing new products from virgin raw material requires processes such as mining, use of fossil petroleum for plastics and fuel, and cutting or growing trees, all of which are detrimental to the environment, and are not sustainable. Recycling paper and plastics would mean that fewer trees would be cut from Canada’s boreal forest and less of Alberta destroyed in extracting petroleum from oil sands.
• Economy—The EPA-data indicates that recycling the 400 MT/d would provide 1500 jobs with better pay than the average of all jobs, and add $25 million (US) to Ottawa’s economy. Recycled materials are essential to industry. Without recycled paper and cardboard, e.g., newspapers could not be printed nor products shipped in cardboard boxes.
Ottawa’s low recycling rate, especially the 17% for commercial waste that constitutes 70% of the waste, provides the opportunity to recycle much more of its waste, saving energy and the environment, while stimulating the economy. Ottawa should follow the lead of San Francisco, Guelph, Edmonton, or Vancouver with a zero-waste goal.
400 MT are actually about 440 US tons.
Your energy recovery efficiency calculations are wrong.
DP
Who can tell me about emissions testing of this process? Any independent studies available? Thanks.
I don't know if there are independent studies, but they show environmental performance on their website at http://www.plascoenergygroup.com/?Environmental_Performance. They use Continuous Emissions Monitoring equipment, and their website says "If you are aware of new and interesting monitoring technologies please let us know about them."
If this technology is all it is cracked up to be I would expect to see a few large metropolitan areas especially in the Northeast, where landfill space is in short supply, to begin lining up with RFPs or more likely sole source contracts for PlascoEnergy to build them some these plants. The footprint is only 3 acres. The future looks very bright for this company and their patented technology if their environmental performance stats are honest. They are not asking Ottawa to fork over any subsidies (other than space) to build the proposed 400 tonne per day plant. They are about to strike a deal with Ottawa where the company would put up all the necessary capital. The company and its patented system appear to be self sufficient and competitive.
using plasma alone to create the reaction of thermal depolyermiation is OBSOLETE technology.
1. the physical limitations of a working plasma torch is about 16 inches and it cannot handle liquids easily due to the rapid expansion to gas.
A better CHEAPER system was reviewed by me in use in Eustis Fla which has a energy balance of over 150% and a coversion to high grade PROPANE of well in excess of 90% using medical waste.
It is EPA and EU certified for the disposal of haardous medical waste and yes it's internal heating elements improvement have been patented.
It runs on the plasma torches powered by 8 modified electric mig welders and is built from off the shelf parts and designed so it can be mass produced .
County Employee looking for advice
Hello: I am a county employee working on the west coast. Our Planning Department is processing a land use application to allow a medical waste processing facility which will use a "gasification" process to treat incoming medical waste. The applicant has indicated that he will use a "closed loop process that involves indirect heating of matter in a closed process chamber under negative pressure" to treat the feedstocks.
I have been able to find very little definitive research on this process. Does anyone here know if there have been long-term tests or other evidence of the viability of this technology?
Any assitance that anyone could provide would be most appreciated.
I came across this article and found the technology and the concept to be very interesting. Garbage is a huge problem, and this seems like an exciting and viable solution. I looked into the company a little further, and it looks like they have done a lot since this blog was first written. I found a really neat video on Plasco’s website that describes the entire process. Here is the link: http://www.plascoenergygroup.com/?Media_Centre#Animated-Video
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152 Comments
Alternative to slag creation
Rather than letting the slag solidify to a dense solid, air can be blown during cooling off of the slag. This creates a high quality insulating material (similar to Rockwool) for use in building insulation. Could be more useful and worth more than just granulate slag.
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