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Mistress Rose

Joined: 21 Jul 2011
Posts: 15996

Posted: Sat Aug 22, 20 8:32 am Post subject:

We have done a bit of willow charcoal for artists, but we were given offcuts from a willow farm. I haven't tried our own willow, but it is bark off for drawing charcoal which makes it rather tedious to make. It worked fairly well in an old tin, but haven't bothered with it lately. I have seen all sorts of things charcoaled in a ring kiln including a deer skull and even seen pottery fired in an earth burn.

Shane

Joined: 31 Oct 2005
Posts: 3467
Location: Doha. Is hot.

Posted: Sun Aug 23, 20 4:38 am Post subject:

Mistress Rose wrote:

I have been thinking for years that rather than landfill, it would be an advantage to utilise waste to produce gas.

An old friend of mine started up a company that did just that. Worked with existing landfill operators to capture the gas given off as the trash decomposed, boosted the pressure and used it to generate power. It deals with the methane given off, but isn't scalable enough to generate a meaningful amount of power in national grid terms. Neat little concept, though.

Mistress Rose wrote:

That and the heat and power stations seem to be a step in the right direction as well as the cleaner alternatives of solar, wind and water power of various sorts.

Combined heat and power has mileage, if you ask me. There was talk of bringing in legislation to force all domestic boilers to go the CHP route (fired on gas), but that wouldn't be particularly futureproof as you'd end up with a nation converted to gas dependency. There is, however, possibly still mileage in municipal CHP, where power stations located near major centres of population (or other heat users) could get cooling by supplying heat to homes and industry. I'd still view this as an interim step, though.

dpack

Joined: 02 Jul 2005
Posts: 46246
Location: yes

Posted: Sun Aug 23, 20 8:04 am Post subject:

land fill from the 1980's onward is energy rich, plasma gasification is our chum to make it burn

iirc the scandinavian plants are having to import it as they have dug up what they had and only create a bit

you can get the metals out before reburying the ash, good scrubbers and burn control reduce pollution to almost nowt

tis still burning fossil as well as other fuels but better than waste and burn new fossil.

Mistress Rose

Joined: 21 Jul 2011
Posts: 15996

Posted: Sun Aug 23, 20 8:25 am Post subject:

I think we may be at the stage with this that we were some years ago with CFCs. We used them extensively for degreasing, defluxing and general cleaning in the electronics industry as well as their uses in refrigeration etc. When I had to leave through ill health, we were trying to find alternatives, which I assume have now been found, but going in all sorts of directions.

Certainly any waste we generate that can't be recycled has great potential for either composting/digestion to directly produce methane and other usable gases, or burning what can't be composted. We do need other forms of heat/power/cooking, and to my mind, at the risk of repeating myself, regulating firewood sales is a very retrograde step. I can see that in dire circumstances people will be using any old stuff to burn on open fires if there is a long power cut, rather than planning it out and having reasonable firewood available if they are put off by propaganda and legislation.

dpack

Joined: 02 Jul 2005
Posts: 46246
Location: yes

Posted: Sun Aug 23, 20 8:41 am Post subject:
a few examples of a major problem

Shane

Joined: 31 Oct 2005
Posts: 3467
Location: Doha. Is hot.

Posted: Sun Aug 23, 20 10:28 am Post subject:

dpack wrote:

Problem is, many of the mitigations are also quite energy intensive. Gasification, for example, needs a source of energy. For coal seam gasification, the energy is supplied by partial combustion of the coal in place, which I guess could work for rubbish, but you'd still use a good percentage of the available recoverable energy just to heat the stuff up to the point at which is gasified.

A flue gas scrubbing system uses around 30% of the power you generate, so much better if you can remove contaminants pre-combustion and control the combustion conditions to avoid generating the nasties in the first place.

dpack

Joined: 02 Jul 2005
Posts: 46246
Location: yes

Posted: Sun Aug 23, 20 1:02 pm Post subject:

CSG is a dreadful process

iirc the rubbish thing is more energy out than in by a long way, and they make leccy as well as heat

the residues are an issue as is the co2 but it does get rid of a lot of bulk, captures waste energy thereby avoiding new energy from fossils and reduces the methane emissions from landfills

if we recycle it will run out but there is a fair bit of energy in half a century of plastics and decayed organic stuff

Ty Gwyn

Joined: 22 Sep 2010
Posts: 4613
Location: Lampeter

Posted: Sun Aug 23, 20 3:00 pm Post subject:

Apparently the last coal opencast in England is due to close at the end of next month,at Stavely near Chesterfield,i was under the impression there was one up the North East so that must have shut down.
An Anthracite opencast in the Dulais valley,South Wales,had an extension licence granted from the CA,local planning,but last month permission was withdrawn by the WA,now its being reclaimed and plans to turn into a train testing site,while they carry on to import Russian anthracite for domestic fuel,while over the mountain in the Neath Valley Aberpergwm Colliery raises between 5 and 6,000 tons of anthracite weekly which is all exported,and a smallmine i used to work in the late 70`s early 80`s raises around 100 ton weekly where the bulk of the graded sizes goes for filtration both water and sewerage outflow,so no more Welsh Anthracite for multifuel burners anymore,just foreign imports.

Mistress Rose

Joined: 21 Jul 2011
Posts: 15996

Posted: Mon Aug 24, 20 7:22 am Post subject:

Another important aspect raised by you there Ty Gwyn. It seems pointless sending things round the world and relying upon other countries, which may have far lower safety and pollution controls than we do in the UK. If anthracite is needed, then it makes sense to mine and use our own. Similarly, we now depend on Russian gas which could be turned off at any time, which would also cause an electricity shortage.

I am not happy about coal gassifcation, but we make charcoal using this system for wood, and in that case there is a lot of excess gas produced. At present we flare off the gas, but the manufacturers of our kiln are working on a way of drying and cleaning it so that it can be used to run a generator or other engine, or stored at low pressure for later use. We are also considering using the excess heat from the chimney to dry wood, as some of the big British producers are doing.

According to the British government we are all supposed to use electric induction hobs and electric ovens (good business to get into with associated pots and pans), and either use waste heat from factories (?) or air sourced heat pumps in our hermetically sealed homes. Open windows and wood fires not permitted. I think the regulations may have come in that no new build is permitted to have chimneys or gas.

Shane

Joined: 31 Oct 2005
Posts: 3467
Location: Doha. Is hot.

Posted: Tue Aug 25, 20 3:57 am Post subject:

Mistress Rose wrote:

waste heat from factories (?)

Basically a big heat exchanger in an industrial chimney or exhaust that either heats up a liquid to provide heat elsewhere or heats up water to generate steam that feeds an electrical generator. A single waste heat recovery unit can produce tens of megawatts of usable heat.

Mistress Rose

Joined: 21 Jul 2011
Posts: 15996

Posted: Tue Aug 25, 20 8:49 am Post subject:

My question mark was what factories? All the factories I have worked in haven't produced much if any heat as they were modern ones for mainly electronics. The 'dark satanic mills' with huge chimneys are rather of the past, and even towns that used to have them are virtually without now. I know that there are still a few industries that do produce heat, but they are very few in our area; in fact I can't think of any. Add to that that most houses are not built in industrial areas and it is not looking like a possibility in most homes.

Slim

Joined: 05 Mar 2006
Posts: 6612
Location: New England (In the US of A)

Posted: Sun Aug 30, 20 12:24 am Post subject:
This recent episode of fully charged really highlights how new tech will increasingly decentralize power and grid peaks and troughs will be mitigated https://m.youtube.com/watch?v=uI7wxNtrorQ

Mistress Rose

Joined: 21 Jul 2011
Posts: 15996

Posted: Sun Aug 30, 20 8:04 am Post subject:

I can see a lot of good points about those houses, but I think there are a number of things that may or may not have been thought about that were not highlighted in this. One is to ensure that rising damp isn't a problem. In the UK, which tends to be a bit on the damp side, particularly Wales where that was filmed, we went from solid walls to cavity wall for that very reason. The next is ventilation. The small block did have opening windows, but they were talking about separating washing and drying clothes. This means that you will have wet clothes hanging around in the house, as well as people breathing out damp air, kettles, baths, showers etc all producing moisture, and if air management is not thought about, mould very quickly develops. All of this may have been thought of, but it wasn't highlighted, and having experienced rising damp from a house where the builders didn't understand this newfangled stuff (1870s build) and having to reduce humidity in a house, they are real problems.

Slim

Joined: 05 Mar 2006
Posts: 6612
Location: New England (In the US of A)

Posted: Sun Aug 30, 20 10:01 am Post subject:

A huge component of modern building science is entirely obsessed with humidity and condensation, because of increased air tightness. I don't know for sure, but would happily wager that they're on top of it. I assume it wasn't mentioned much because of a blend of it being par for the course for modern building of efficient homes, and because the show is specifically about transferring to clean energy and not building science generally.

*Edited for auto-incorrect and clarity

Last edited by Slim on Sun Aug 30, 20 1:41 pm; edited 1 time in total

tahir

Joined: 28 Oct 2004
Posts: 45676
Location: Essex

Posted: Sun Aug 30, 20 1:26 pm Post subject:

I have t watched the video but we’ve built 3 houses to passive house spec now. Getting better each time. Our latest build will be approx 0.4 m3/hr per m2 vs current Uk building regs of 10m3/hr, most new builds are 3-5m3/hr

I can guarantee our builds will handle humidity and damp better than a “normal” new build. To build to that level ventilation has to be a core part of the design, even at the appalling level allowed by building regs you can end up with a drafty house prone to condensation hence damp.

We’ve lived in our house (0.76m3/hr), it’s a very well used house; 5 of us, people staying 200ish kg of jam made, 40kg of chilli sauce every year. Loads of humidity sources but the least damp prone house I’ve ever lived in, and it uses less power than the old house which was 1/3rd the size

Last edited by tahir on Sun Aug 30, 20 1:29 pm; edited 1 time in total

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