Good morning Mastodon!
-
The plant takes residual waste from mid Devon where I live, so some of my illegible scrawls may have been illuminated by photons generated from my very own household's cat turds and plastic films. It doesn't take all the University's waste, which not including specialist chemical and biological waste generated by the laboratories is managed by three separate subcontractors. The student accommodation blocks are managed by two separate contractors, who contract out their waste collection to different contractors, and the non-accommodation buildings have another separate waste collection contract. Very illogically waste doesn't go to the nearest disposal facility, it could be trucked across the country to the one the cheapest contractor has a contract with.
@afewbugs what are the emissions from the plant ?
-
The Marsh Barton facility isn't actually owned by the council, it has a contract with company Viridor which it pays to operate it. This is all utterly insane and probably Margaret Thatcher's fault.
@afewbugs What isn't, really?
-
@afewbugs what are the emissions from the plant ?
@quixoticgeek I'm getting to that but there's a spoiler here if you want to skip ahead https://www.viridor.co.uk/exeter-emissions-data/
-
The Exeter plant produces 24,000 MWh/year. I've written down that it consumes 75 somethings for its own operation and exports the rest to the grid, but this will be amended with the correct more legible figure when I get a copy of the presentation.
@afewbugs that's only a ~2.7MW power plant. Less than a modern wind turbine. That's lower than I expected.
-
The Marsh Barton facility isn't actually owned by the council, it has a contract with company Viridor which it pays to operate it. This is all utterly insane and probably Margaret Thatcher's fault.
@afewbugs I suspect use of the communal heating only in RN barracks and dockyard is because military is often the only well funded and trusted public sector organisation these days, and they have the clout to impose on sailors and shipbuilders what heating solutions are used rather than let them choose their own.
There are district heating schemes in Britain but very few and ever since the govt has considered increasing regulation and demanding more customer service no private businesses want to build them..
-
The Marsh Barton facility isn't actually owned by the council, it has a contract with company Viridor which it pays to operate it. This is all utterly insane and probably Margaret Thatcher's fault.
Here's a schematic of the process.
-
@afewbugs that's only a ~2.7MW power plant. Less than a modern wind turbine. That's lower than I expected.
@quixoticgeek The primary purpose it was built for is disposing of waste, not creating energy I think. There are much more efficient ways to produce electricity, and the energy density of household waste is apparently very variable and often fairly low, depending on what's getting burnt
-
Here's a schematic of the process.
So starting at the beginning of the proccess, waste collection lorries drive in and drop residual waste into this great big pit that may or may not have a giant space octopus at the bottom
-
So starting at the beginning of the proccess, waste collection lorries drive in and drop residual waste into this great big pit that may or may not have a giant space octopus at the bottom
Waste is then collected from the pit using this giant claw and dropped into the hopper feeding the kiln
-
Waste is then collected from the pit using this giant claw and dropped into the hopper feeding the kiln
When we visited the world's biggest claw machine was operated by an extremely tolerant bloke called Ashley, who very good naturedly answered all our questions while trying to get on with his job. A couple of people told him he had the coolest job in the world, to which he replied that it had been for the first six hours or so but after that it got a bit boring.
-
When we visited the world's biggest claw machine was operated by an extremely tolerant bloke called Ashley, who very good naturedly answered all our questions while trying to get on with his job. A couple of people told him he had the coolest job in the world, to which he replied that it had been for the first six hours or so but after that it got a bit boring.
The reason waste is manually dropped into the kiln by a bloke in fancy chair, instead of just fed in automatically by gravity or something, is to make sure that nothing too big goes in that would block the hopper but also to make sure no animals or people end up falling in. As the plant runs continually apart from planned shutdowns for maintenance there is a bloke doing this 24/7, as well as support staff on site at all times. There are always at least two people in the control room.
-
The reason waste is manually dropped into the kiln by a bloke in fancy chair, instead of just fed in automatically by gravity or something, is to make sure that nothing too big goes in that would block the hopper but also to make sure no animals or people end up falling in. As the plant runs continually apart from planned shutdowns for maintenance there is a bloke doing this 24/7, as well as support staff on site at all times. There are always at least two people in the control room.
The actual incineration and heat generation takes place in a giant rotary kiln, which looks like a gigantic insulated cement mixers. The best I can do for you for a picture right now is some fire on a screen I'm afraid, there was a great photo of it being lowered in to place with a person for scale in the presentation and I assumed I'd be able to find that on the internet somewhere but I haven't been able to. I'll add it hen I get the email of the presentation.
-
The actual incineration and heat generation takes place in a giant rotary kiln, which looks like a gigantic insulated cement mixers. The best I can do for you for a picture right now is some fire on a screen I'm afraid, there was a great photo of it being lowered in to place with a person for scale in the presentation and I assumed I'd be able to find that on the internet somewhere but I haven't been able to. I'll add it hen I get the email of the presentation.
@afewbugs Literally rode past it not half an hour ago!
-
The actual incineration and heat generation takes place in a giant rotary kiln, which looks like a gigantic insulated cement mixers. The best I can do for you for a picture right now is some fire on a screen I'm afraid, there was a great photo of it being lowered in to place with a person for scale in the presentation and I assumed I'd be able to find that on the internet somewhere but I haven't been able to. I'll add it hen I get the email of the presentation.
The rotary kiln for the Exeter plant was built in France, managed to cross the whole of France on an articulated lorry, was successfully shipped across the channel and driven across most of Southern England, then got stuck on a narrow road through the Haldon Hills and had to be extracted by crane.
-
The rotary kiln for the Exeter plant was built in France, managed to cross the whole of France on an articulated lorry, was successfully shipped across the channel and driven across most of Southern England, then got stuck on a narrow road through the Haldon Hills and had to be extracted by crane.
@afewbugs Your rubbish thread today is pure 100% treasure
-
The Marsh Barton facility isn't actually owned by the council, it has a contract with company Viridor which it pays to operate it. This is all utterly insane and probably Margaret Thatcher's fault.
@afewbugs Things mostly are.
-
The rotary kiln for the Exeter plant was built in France, managed to cross the whole of France on an articulated lorry, was successfully shipped across the channel and driven across most of Southern England, then got stuck on a narrow road through the Haldon Hills and had to be extracted by crane.
Actually I can do a bit better than fire on a screen. I hope you like videos of the edge of something rotating very slowly just about visible between bits of an industrial facility Mastodon.
-
The reason waste is manually dropped into the kiln by a bloke in fancy chair, instead of just fed in automatically by gravity or something, is to make sure that nothing too big goes in that would block the hopper but also to make sure no animals or people end up falling in. As the plant runs continually apart from planned shutdowns for maintenance there is a bloke doing this 24/7, as well as support staff on site at all times. There are always at least two people in the control room.
@afewbugs I've been to the Oxfordshire one, looks very similar. There were two grabs with potentially two operators, although only one human in place when we visited. The grabs here did operate remotely/automatically over night. The manual input was required to stir/mix the input
-
Actually I can do a bit better than fire on a screen. I hope you like videos of the edge of something rotating very slowly just about visible between bits of an industrial facility Mastodon.
Waste gases coming out of the kiln are mostly carbon dioxide from the combustion of all those carbon-based plastics that didn't make it to recycling and organic materials. They shared this interesting slide of what residual waste is actually made up of, after doing an extensive and probably deeply unpleasant survey separating out and weighing the contents of those bags. A depressing amount could have been composted or recycled
-
Waste gases coming out of the kiln are mostly carbon dioxide from the combustion of all those carbon-based plastics that didn't make it to recycling and organic materials. They shared this interesting slide of what residual waste is actually made up of, after doing an extensive and probably deeply unpleasant survey separating out and weighing the contents of those bags. A depressing amount could have been composted or recycled
Within the carbon dioxide are various toxic gases, which are neutralised chemically, and heavy metals and other particulates which are extracted by filter to produce fly ash. This is then neutralised by this company to produce building aggregates: https://oco.co.uk
You can see emissions data for the plant here: https://www.viridor.co.uk/exeter-emissions-data/
