Waste to Energy
- Thread starter peakbagger
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
SpaceBus
Minister of Fire
I noticed the trays at the hospital in Ellsworth are made of recycled (cellulose I assume) fibers.
I think this would just blow it up over Maine, Nova Scotia, and Newfoundland
My guess is its a newer plant with the right emissions control technology. Its actually inland a bit from the shore. My guess is they have sorbent technology upstream of scrubber. it was developed to clean up the coal industry and its pretty amazing stuff. Looking at the stack at the site, its pretty low which implies that if there are nasties it would have low level impacts. There is major insurance company complex that has been developed over the years right across the highway and a very well off neighborhood just a short distance away. I expect there if there were any nasties coming out the stack there would be plenty of well funded NIMBY folks lined up to fight it.
The permit is public record if I want to spend the time digging for it. That should summarize the technology.
Here is a link to the permit. Several pages in is a nice sketch of the system.
Looks like I guessed right. It lists lime and carbon as sorbent for the nasties' followed by a scrubber to take the big sorbents out of the air steam, then a electrostatic precipitator to take out small particulate. The boiler uses an inclined stepped grate which is also pretty well the current standard for a grate. Overall it may not be absolute state of the art but pretty darn good, far better than the units built in the eighties that didn't use sorbents, scrubber or SCR. They do have Selective Non Catalytic Reduction (SCNR) NOX system which might be a bit old school compared to a Selective Catalytic Reduction (SCR) catalyst but in order to put a SCR in they would need to reheat the gases downstream of the electrostatic precipitators to get the gases back up to reaction temperature as otherwise the catalyst would get plugged with particulate. It can be done but that means another source of fuel to be combusted where as SCNR just sprays the ammonia into the boiler at the right temperature zone. The spent sorbents get mixed with the ash stream and I expect landfilled. There are sometimes beneficial uses for ash but potential long term liabilities in case something not currently controlled is in the ash. The general approach is landfill it where it may have some use for thickening wet solids or for temporary roads. They also have a magnet on the bottom ash conveyor to grab any magnetic materials for recycling but expect that's a borderline proposition unless recycling markets are doing well. . Notice the air flow pattern through the building, they keep the air flow "negative" through the trash receiving area to keep the facility from smelling outside the plant . I expect it gets "ripe" inside during warm weather.
Note all these emissions controls have a heat rate cost so the plant puts out less power as more power is used internally to run the emissions equipment. The sorbents also cost money to buy and dispose. The communities that support it would need to truck the waste to the nearest landfill if they didn't have the plant . The nearest landfill which I think is Rochester NH is about 60 miles away. Some states limit import of trash so the next closest landfill in Maine is around 70 miles. They would be trucking a lot of air in the unprocessed waste and burning diesel to do so. Instead they only need to landfill about 1/10 the the volume and weight of ash. They also have an integrated recycling facility so they are attempting to get the recyclables out of the system. Not sure how fancy they get with recycling. Ferrous metals are easy to grab but non ferrous not so much. I think there are some devices that can sort non ferrous out of waste stream but not sure exactly how.
I don't think the plant has any district heating opportunities due to its location, but in Europe they put in stainless steel stacks and condensing heat exchangers upstream of the stack to heat water with flue gas that is then pumped to local district heating system. The flue gas plume gets pretty cool so they need a very tall stack to get reasonable dispersal.
A properly run plant like this is expensive to build and run but its beats many of the alternatives. That is why most of Europe and Japan have adopted it.
Looks like I guessed right. It lists lime and carbon as sorbent for the nasties' followed by a scrubber to take the big sorbents out of the air steam, then a electrostatic precipitator to take out small particulate. The boiler uses an inclined stepped grate which is also pretty well the current standard for a grate. Overall it may not be absolute state of the art but pretty darn good, far better than the units built in the eighties that didn't use sorbents, scrubber or SCR. They do have Selective Non Catalytic Reduction (SCNR) NOX system which might be a bit old school compared to a Selective Catalytic Reduction (SCR) catalyst but in order to put a SCR in they would need to reheat the gases downstream of the electrostatic precipitators to get the gases back up to reaction temperature as otherwise the catalyst would get plugged with particulate. It can be done but that means another source of fuel to be combusted where as SCNR just sprays the ammonia into the boiler at the right temperature zone. The spent sorbents get mixed with the ash stream and I expect landfilled. There are sometimes beneficial uses for ash but potential long term liabilities in case something not currently controlled is in the ash. The general approach is landfill it where it may have some use for thickening wet solids or for temporary roads. They also have a magnet on the bottom ash conveyor to grab any magnetic materials for recycling but expect that's a borderline proposition unless recycling markets are doing well. . Notice the air flow pattern through the building, they keep the air flow "negative" through the trash receiving area to keep the facility from smelling outside the plant . I expect it gets "ripe" inside during warm weather.
Note all these emissions controls have a heat rate cost so the plant puts out less power as more power is used internally to run the emissions equipment. The sorbents also cost money to buy and dispose. The communities that support it would need to truck the waste to the nearest landfill if they didn't have the plant . The nearest landfill which I think is Rochester NH is about 60 miles away. Some states limit import of trash so the next closest landfill in Maine is around 70 miles. They would be trucking a lot of air in the unprocessed waste and burning diesel to do so. Instead they only need to landfill about 1/10 the the volume and weight of ash. They also have an integrated recycling facility so they are attempting to get the recyclables out of the system. Not sure how fancy they get with recycling. Ferrous metals are easy to grab but non ferrous not so much. I think there are some devices that can sort non ferrous out of waste stream but not sure exactly how.
I don't think the plant has any district heating opportunities due to its location, but in Europe they put in stainless steel stacks and condensing heat exchangers upstream of the stack to heat water with flue gas that is then pumped to local district heating system. The flue gas plume gets pretty cool so they need a very tall stack to get reasonable dispersal.
A properly run plant like this is expensive to build and run but its beats many of the alternatives. That is why most of Europe and Japan have adopted it.
Last edited:
semipro
Minister of Fire
I wonder if this is still true when you consider life cycle aspects and newer incineration and contaminant capture technologies.
It seems that for now at least, GHG production issues relegates incineration to a last resort.
When my wife was a student in college, their class was invited to tour the waste to energy plant in Grand Rapids, MI, so I decided to tag along. All refuse was dumped into a pit where a large grapple would grab scoops of debris and feed a huge conveyor belt. I powerful magnet would pull out the metal, and I believe the glass was also separated somehow. The rest went into the incinerator which burned at a very high temperature. The entire process was quite fascinating to see, but a little smelly. This was about 25 years ago, so they may have made some modifications, but it kept a lot of trash out of the landfill and produced energy. Even if it's a zero sum game it's a win. For those of you interested here's a link.
www.reimaginetrash.org
Waste to Energy Facility - ReimagineTrash
Reimagine Trash… as a resource, as a feedstock, as an opportunity.
www.reimaginetrash.org
Old school incineration, but effective in reducing the volume that ends up being landfilled. The downside is the emissions. WtE can be done well, but most systems in the US are 40+ yrs old and dirty.
True, but with today's technology, it would be nice if the older plants can be retrofitted with more efficient scrubbers.
A waste to energy incinerator lives a fairly hard life and the way that trash is burned has changed. Yes an older plant can have an emissions upgrade but generally its throwing good money after bad as the rest of the plant is wearing out so "up time" is reduced as all the supporting systems are getting old. Modern plants also have changed the way waste is brought into the facility to reduce the odor from the trash. The air emissions laws also factor in, if an owner spends over a certain amount to rebuild a plant, the plant can be subject to new plant performance standards.
Older plants are usually "grandfathered" to the performance standards that cover the entire plant, technology and pollution standards improve over the years so new plants need to meet the new standards. It frequently not practical to upgrade the entire plant to the new standards so the owner is better off finding a willing host offering better incentives and building a new plant. Waste to energy is generally not profitable from an energy production basis, its really waste minimization facility with an added benefit of electric power and waste diversion. The Europeans pretty much banned burying trash so the next best thing was to burn it.
Older plants are usually "grandfathered" to the performance standards that cover the entire plant, technology and pollution standards improve over the years so new plants need to meet the new standards. It frequently not practical to upgrade the entire plant to the new standards so the owner is better off finding a willing host offering better incentives and building a new plant. Waste to energy is generally not profitable from an energy production basis, its really waste minimization facility with an added benefit of electric power and waste diversion. The Europeans pretty much banned burying trash so the next best thing was to burn it.
I agree, as with anything there are generally a downside, a win-win is very rare. At least you are gaining electricity or steam from an incinerator vs burying the problem for future generations to deal with. It would be nice if the "smart" people could come up with a standardized plant that could easily be replicated over and over, which would reduce cost. As we've talked about plastic doesn't go away, at least not in the short term, and recycling is just a feel good measure in many areas of the country, there is just not enough demand for recycled plastics, which is the main culprit.
Covanta bought the rights to one of the German technologies, they are about as close to standard plants in the US. I used to work on some regional biomass plants that were "cousins" they were a somewhat standardized layout with some minor differences.
My guess for plastics is convert them back to oil and make the oil companies use a portion of the plastic derived oil in fuel.
I spent 2 years moving frozen goods from a truck into a walk in freezer and then out to the coffins in the store. Good high school job.
Uncle Sam taught me a bunch of cool stuff, let me play aircraft carrier reactor operator for a while, then had me repairing submarine engine rooms. That was a fun 10 years. Guys used to dream about their post military aspirations. One popular joke was "riding around on the back of a garbage truck." LOL.
I did a 6 week maintenance outage as a health physics tech at a dual 850 MW PWR plant down south. Interesting and fun, but I had enough of living out of a suitcase (seabag).
I don't pay for garbage disposal, it goes to work with me. I've been burning societies unwanted leftovers for the past 20 years. It's a fascinating evolution and pays quite well. Updraft gasification, 2000 deg F in the fuel bed, SNCR (urea) injection in the furnace for Nox control, carbon injection (heavy metal) and lime slurry (acid gasses) treat the exhaust before the flue gas is scrubbed by hepa filters in the baghouse. Gross metals are removed from the ash stream. Ash is processed again at the landfill for further (smaller) metals removal via magnetic & reverse magnetic separation. My plant is relatively small at 500 tons per day. 15 MW/hr (2 MW house load, selling 13).
I often wonder why we don't have a WTE facility located next to every landfill in the US mining yesteryears garbage and recovering the energy and recyclables from it.
Uncle Sam taught me a bunch of cool stuff, let me play aircraft carrier reactor operator for a while, then had me repairing submarine engine rooms. That was a fun 10 years. Guys used to dream about their post military aspirations. One popular joke was "riding around on the back of a garbage truck." LOL.
I did a 6 week maintenance outage as a health physics tech at a dual 850 MW PWR plant down south. Interesting and fun, but I had enough of living out of a suitcase (seabag).
I don't pay for garbage disposal, it goes to work with me. I've been burning societies unwanted leftovers for the past 20 years. It's a fascinating evolution and pays quite well. Updraft gasification, 2000 deg F in the fuel bed, SNCR (urea) injection in the furnace for Nox control, carbon injection (heavy metal) and lime slurry (acid gasses) treat the exhaust before the flue gas is scrubbed by hepa filters in the baghouse. Gross metals are removed from the ash stream. Ash is processed again at the landfill for further (smaller) metals removal via magnetic & reverse magnetic separation. My plant is relatively small at 500 tons per day. 15 MW/hr (2 MW house load, selling 13).
I often wonder why we don't have a WTE facility located next to every landfill in the US mining yesteryears garbage and recovering the energy and recyclables from it.
It's been many decades since I lived in CT. These plants went in after I left. It looks like CT has 6 WTE plants. Does the state or do the facilities provide emissions data for things like dioxins?
How good are the recycling programs there now? Do they aggressively recycle first or do they burn everything in lieu of recycling?
How good are the recycling programs there now? Do they aggressively recycle first or do they burn everything in lieu of recycling?
With tail end equipment like that I expect Dioxin and mercury are close to non detect. I am surprised I didnt see a bit of Trona injection but due to trucking costs, carbon gets used a lot in the East coast. Not cheap to build. Its the same sort of tech used in Germany and Japan. A plant like that is never going to break even just selling power, its got to be have another stream of revenue from tipping fees and that means driving up the cost of landfills by making them very expensive, outlawing new ones or just banning trash to be put in them.
Most areas in the US dont have the political will to put in a properly designed WTE plants, they just want the trash gone and preferably not in their backyard.
Most areas in the US dont have the political will to put in a properly designed WTE plants, they just want the trash gone and preferably not in their backyard.
I remember reading we essentially burn all our trash in WTE plants in CT. I think we were early adopters to the technology but the plants are outdated. There was big news last year when a 1920s coal plant converted in Hartford to a WTE plant decades ago lost a turbine and was down for months. There are no active landfills in CT so the trash had to be hauled to PA by truck at extremely high cost.
I think we have a strong recycling program here and believe all the trash is sorted for metals, plastics, etc before its burned. One issue that needs work though is I remember reading that when they analyzed the trash being burned it was mostly food waste.
Helping is also the fact that we have like the 2nd highest electricity rates here after HI. I'm sure that plays a big role. There are proposals to update many of the plants as with no active landfills I'm sure it beats trucking the waste out.
CaptSpiff
Minister of Fire
Don't bet on trucking being cheaper, PA is increasing their tipping fees each year.
We (Long Island) are in the same boat as CT. Most of our land fills were closed and capped back in the 80's. We got about half a dozen WTE plants under the 1980's PURPA regs. They have been mostly consolidated under the Covanta energy banner. Local jurisdictions levy a sanitation tax, which pays private carters to collect and tip at these local WTE plants. The tipping fees are negotiated with the local jurisdictions, who also guarantee minimum levels of tonnage. The tipping fees are pretty high, so the carters try to remove metals (bicycles, bed frame rails, etc) at pickup. The WTE usually burns everything and does its metal separation at the ash handling process. The metal is a small revenue source, the ash is trucked out.
There were some very bad pollution incidents in the early 80's with the WTE's , but the newer designs along with tight inspections have made these WTE plants pretty good neighbors.
I will agree on the early US plants being dirty. PURPA passed in 1978 and with the avoided power rates being offered, WTE was slam dunk, the plants got high prices for power plus tipping fees. The EPA regs really didnt deal well with WTE and the developers were in rush to cash in. The net result were poorly built plants with marginal emission controls. Once built the communities that depended on them didnt have a lot of options so they kept them running. Once the initial PURPA contracts ran out the original developers were long gone and the economics got far less lucrative they kept running on a tighter margin and many tended to let them deteriorate. In one case a landfill owner bought a plant for cheap in Biddeford Maine, then ran the plant for few years and then got the community to pay to shut them down.
Sounds like Connecticut's CRRA program is pretty good. I checked the old hometown (Cornwall, CT) recycling program and it's quite robust. CRRA pays them to recycle. Good going.
Looks like the new first in the nation waste recycling technology plant in Maine is in financial difficulties https://bangordailynews.com/2020/06...rations-on-hold-as-it-struggles-to-pay-bills/
SpaceBus
Minister of Fire
Not surprising given the global atmosphere at the moment. Crazy times we are living in.
Similar threads
