Retro fitting gas burners in coal power plants.

Jan 26, 2016 29 Replies

Hello all,



Reading an article in the Guardian (yes, I know) about a looming electricity shortage, one of the reasons cited was the phasing out of coal-fired generating capacity:


How much of a pain / why can't coal plants be converted to gas if they are cleaner on the emmissions front?



Thanks in advance



David Paste.


In message , David Paste writes

From very limited knowledge and roughly 40 years ago.... we looked at converting oil fired boilers to gas and found they would need to be hugely derated because the gas flame for the same energy would be too long and hit the back of the burner tube. I guess coal, which may be powdered before injection, might have a raft of similar issues.

An expert will be along shortly:-)

Apart from this, even if you can get the flame to work in a boiler designed for coal, you will only get the 40% thermal efficiency of a coal plant. Whereas, if you burn it first in a gas turbine and then heat steam with the exhaust you have approaching 60% thermal efficiency. Although we used to think of "jet engines" as being expensive, high tech kit they are now mature technology.

I think they probably count as mature, expensive, high tech kit :-)

I suspect power plants use gas turbines rather than heating water to create steam - but, as you say, an expert will be along soon.

CCGT uses *both*

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I wondered this as well, but I'd suspect it would not be a trivial mod and taking any out of action for such a thing now would seem to not be a good thing. After all they could burn waste as well, if they brought in the correct furnaces. Brian

Except the fuel they burn costs many times the hardware that burns it!

I missed the original post somehow, but FRedxxx has it pretty much spot on as far as I am concerned.

To be economic a gas power station needs to be combined cycle - due to the price of gas mainly. Just about the only part of a coal power station that is usable would be the alternators.

It would make more sense to convert a coal plant to nuclear. You aren't concerned much with efficiency, with nuclear. Uranium is dirt cheap.

I've long been suggesting building nuclear steam raising plant alongside th e coal boilers. The turbines, switchgear, control room, cooling towers, gri d connections and workforce are already in place. To the OP don't imagine a pulverised fuel coal fired power station boiler b ears much resemblance to a domestic or even an industrial unit. If you cont act your nearest station and ask if they have an open day coming up or if y ou could be attached to an organised tour I'm sure they would oblige. I tou red Drax in the 1970s with one of the station engineers and it's an impress ive site. Everything from the "merry go round" coal delivery system to the

400kv switchfarm gates. Even thinking of shutting it is just plain crazy.

In message , snipped-for-privacy@gmail.com writes

Umm.. Nuclear plant seems to be sited next to a good source of cooling water. Coal sited close to the fuel source.

Coal fired sites also need water. Rivers: like the Trent are good. Think Battersea & Bankside for Thames water or others close to the sea. Coal was/is brought by train

Power stations need two things: good source of fuel and good source of cooling water. All the power stations I can think of are beside rivers so the river water can be pumped to the power station to cool the recirculating clean water, with some of the river water going up the cooling towers as steam and the majority (once it has been cooled to an environmentally friendly temperature) being pumped back into the river further downstream.

Except that 40 year old turbo alternators, CW systems, switchgear etc are coming to the end of their life.

There are seaside ones, too. Most of the Nuclear ones are by the sea, but Longannet, in Fife is seaside. There are probably others.

Most of the plant has been regularly maintained during planned unit outtages. Every thing can be refurbished if required and is not beset by eco loons objecting at every stage of the planning process for a new station.

Most of the plant has been regularly maintained during planned unit outtages. Every thing can be refurbished if required and is not beset by eco loons objecting at every stage of the planning process for a new station.

The most valuable part is the massive iron-cored transformer. The one from Didcot was salvaged and taken back to the Siemens factory in Germany (*) for a refurb and it will then be installed in one of the many brown-coal fired stations that the Germans are building.

(*) Was pictured on ITV meridian on a special low-loader, using a route that avoided bridges, on its way to a ferry somewhere near Bristol.

En el artículo , newshound escribió:

That's true. I watched a TV programme (Power to the People) recently about Ferrybridge C (coal-burning) station. >50 years old, due to close in March this year. They're basically keeping it running on string and sealing wax. The large metal baskets in the maintenance area showing ancient, obsolete, motors, valves etc. for repair said it all.

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Easy to refurbish though. New bearings in the generators etc.

The DRAX merry-go-round came to an end recently when the last deep mine closed. Now all the fuel is imported.

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