[Stoves] Off-topic: Biomass power and charmaking

[Crispin Pemberton-Pigott]

Daniel

While I appreciate in some detail your imagined concerns, it is important (if you aspire to be taken seriously in a policy discussion) that you are able to quantify claims, effects and consequences.

"They are full of Mercury and arsenic, even radioactive elements."

 Define "full of". Everything on the planet has mercury in it, even the air. It is a natural substance and it occurs in multiple forms. Some are harmful, some less so, some are not. People's fillings have honking great lumps of mercury in them yet they don't get Minimata Disease. Why?

People are largely made of carbon, and so are black carbon smoke particles. The latter is toxic for the former, if there are enough embedded in them.

The late Professor Philip Lloyd was very "up" on the mercury issue because of the over-the-top scare stories about curly lamps (CFL's). He said in the whole Cape Town area there was about 30 kg of mercury in lamps.  A power station puts out more than 100 kg per hour in mercury compounds for which there is no evidence of effect on the surrounding community, near or far.

As soon as we talk about a "contaminant' we have to talk about the dose. The disease or the cure is in the dose.

Arsenic: mentioned in the introduction to the GACC's stove comparison paper and chart (prepared by Berkeley). It says there are some coals that contain toxic levels of arsenic, meaning the chimney emissions have a concentration high enough to cause health problems either for the user or the whole community. This is true for a region in SW China. They should not burn those coals. Not in a domestic device, anyway.

But that cannot be used as an excuse to claim, as that document does, that no one should burn any coal found anywhere on the planet.

The same applies to fluoride in coal. Where that occurs in the same area, there is a terrible fluorosis problem in people, but the water is also contaminated. They should not drink it untreated (arsenic in water is easy to treat - Canadian invention. See Bangladesh and the arsenic in water problem.)

Of course there is uranium in coal ash just as there is uranium in all soil and all food and wood and clothes not made from plastic. It is everywhere. How much? Which isotope?

The coal from mines near Ulaanbaatar have much more uranium than most other places in the world. The whole of Central and Eastern Mongolia is " uraniferous".  There is a guy there who is always looking for money to research "this terrible problem", the problem being the "concentration" of the ash when the coal is burned and dumper in the yard, and people pitch a yurt on top of it and live there.

Sounds dangerous, right? Everything in favour of something health-damaging. Concentrated uranium-containing "waste" from evil coal. So, Prof Lodoysamba, who is a nuclear physicist, investigated this 'dangers' with appropriate instruments and quantified the radiation from the natural source.  There is radiation, as one expects, and spending 24 hrs sleeping on the  "contaminated" ground is the equivalent of standing outside for one hour under the stars.

The sky showers us with ionizing radiation all the time. It is important to "get real" about these things. Environmental bogeymen.

The USA has been scoured for decades looking for evidence of a "mercury plume" or a lake affected by acid rain, or a radiation footprint.

Before complaining about heavy metals in your pizza, we should have some understanding of the scale of the "contamination". Maybe your body needs microscopic intake of all natural elements. Selenium, for example. If you have too much you get really sick. Is this a surprise? To whom?

TCDD dioxin was discovered in the packaging of milk in Ontario - the paper cartons. The source was the trees from which the paper was made, which grew in a place affected by forest fires a century ago. It (2,3,7,8-Tetrachlorodibenzo-p-dioxin) is a natural substance. So what was the dose? Fifty parts per trillion. Just because something is detectable doesn't automatically mean it is toxic.

People hate coal because it smokes. And it burns in a Smokey fashion because most people don't know how to burn it properly and have never heard of or seen a very low emissions combustor.

Another reason to hate coal ash ponds is the high pH of the material. Recently, especially in the last ten years, materials scientists are learning how to polymerize it in O-Si-O-Al-O-Si-O form to make geopolymer materials which set like cement. "Waste ash" will soon be seen to be free cement, and they might even pay you to take it away.

Similarly sintered reduction of clay minerals offer materials with remarkable high temperature properties and low cost.

Where there's muck, there's brass, as they say.

Humanity is not going to develop backwards.

Regards
Crispin



Crispin, everytime I hear you talking about burning coal I think of the toxic ash dumps all over America. They are full of Mercury and arsenic, even radioactive elements. Doesn't your coal over there have heavy metals? Those metals also are emitted in the exhaust.  I cannot imagine cooking over that stuff. Now some of the Antharcite ( hard coal)from Pennsylvania seems to have lower heavy metals. They are cooking pizza on it and nobody is complaining about heavy metals so.... Dan

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On Mar 5, 2019 9:58 PM, Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
I have long given up on the EPA taking AA scientific path to anything. I don't know what they are up to, but it is not what I thought.

Duff coal (under 6mm) is easily separated into +2mm and dust. The problem with the dust is not that it is unburnable but that it is wet and very expensive to dry. It holds the moisture rather efficiently.

So how to create a usable product? First Gerrie of the "rock" which is to say, powdered rock which is ash. Because it has been ground to a powdered state by handling and crushing, the ash, or a lot of it, can in theory be removed by flotation in a dense media, but that makes it wet. Big problem.

So by blasting air over it or under it, a fluoridation takes place AND water evaporates so it is possibly to get three fractions rather inexpensively: the light fraction (density 1.4) which would have floated on the dense media, then the ash which is rock at the bottom (density >2.5) and "middlings" which in a normal is wasted as well because few want it.

Neither do we.

So the light fraction is pretty clean coal. Being powder and if it is South Africa, it has enough bitumen to be pressed hard and it will stock together without any binder.

Thus we can get say 60m tons of high quality high energy coal pellets of just the right size and shape, while stopping the auto-ignition of the stockpiles (followed by a decade of terrible combustion).

The use of air to separate gold dust from dirt was extensively used in the gold rush days in southern Australia. Water was extremely expensive and had to be brought by ox cart some huge distance. So the gold was pre-concentrated by fan a couple of times and then the precious water did the final washing.

Philip Lloyd did a lot of work on trying to find viable ways to use this wasted resource. Before him Prof Horsfal at Wit's Univ worked on semi-coking on the basis that smoke could be removed from the coal, rather than that a good stove wouldn't make any.

Stay well
Crispin
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Subject: Re: Off-topic: Biomass power and charmaking


Crispin:

Density of demand makes the portability of densified fuel relevant. In and of itself, fuel density is no matter. "Marketable radius" implicitly refers to demand density; Washington, DC gets wood from within 30 miles if that, but charcoal briquettes from hundreds of miles, and much of northern and coastal part of US is in the same fortunate situation because it has the money to go with its preferences. Biomass fuel logistics are relatively easy. Otherwise transport, storage and retailing costs do not necessarily favor denser fuels.

Think or uranium.

My favorite anecdote is from around 1980 when petroleum products were FLOWN to an African country. (Rwanda or Burundi or CAR.) Dense fuels, once adopted, should be stockpiled. (I once worked on storage tanks and railway or pipeline alternatives in central Africa. I don't think densified solid fuels other than charcoal or briquettes have a prayer in Africa yet.)

I wish I could go back 60 years and compute the economics of chunk charcoal, charcoal briquettes, kerosene, and stoves in my home and hometown.

I wonder how you would "wash" coal with air. (I spent close to a year on litigation involving water-washing of Pennsylvania bituminous coal to drive out sulfur to meet the EPA standard for SO2 emissions. That is when I went to see the washing plant to understand how elemental sulfur could be washed off but organic sulfur couldn't, and that coal seams are not of uniform quality to satisfy EPA fancies. That is also when I confirmed that EPA can be capricious and political, despite all its purported competence in science.)

Nikhil Desai
Skype: nikhildesai888

On Mar 3, 2019, at 7:59 AM, Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:

Dear Michael

Your reply inspires the following:

Should we classify charcoal briquettes made from ag-wastes as "densified fuels?

The conversion of a low use, unused or useless byproduct into something saleable can be viewed from the perspective of economically viable portability, probably in terms of a "marketable radius" [km]. The radius for rice hull is X and the radius for charcoal briquettes is 5X, for example.

What makes packaged energy portable is densification. Normally this is referred to as mass density but for practical purposes, or energy discussion, being more energy dense is also valuable: consider LPG v.s. ethanol.

There is a discussion taking place off list between some of us here about the densification of coal fines (duff coal) which is piled in South Africa on an enormous scale, more than 200 m tons I suspect. It is essentially free and is an environmental problem because it blows around, catches fire by itself and is ugly.

By itself it is not a great fuel, even if briquetted because it has so much ash in it. So the proposal is to wash it using air and take the top one third and use that as fuel material, sizing it appropriately for a cooking or heating device.

It would yield about 1,500 million GJ of energy. It becomes useful in terms of shipping it around if it could compete with run-of-mine sized and washed coal due to its "energy densification".

The same applies in principles to ag-wastes. Physical densification is helpful because it makes "pellets" of an appropriate size (or could - many compressed wood products are inappropriately large).

Looking at examples from China, there are two issues for the use of straws (ignoring mechanical issues which we presume will be resolved). They are 1) the transport radius to a "compression site" where the mass densification takes place (big electrical power required) and 2) the transport radius to a market - possibly the same farms or villages around the farms.

The current distribution radius is a 150 kilometres. That is the economic limit with a subsidy from government of about $7 a ton as a biofuel.

When the product is energy-densified the radius is enlarged considerably on the marketing side because it is lighter per MJ and it is worth more to the end user (when storage volume is considered, for example).

So there are in this approach two radii: the collection radius and the distribution radius with an autocorrelation (to borrow a word from statistics) between them. A higher selling price means a higher purchase price is possible.

What is happening in Hebei Province, which I described already, is the conversation by energy densification of field straw into char, and marketing it in other provinces. This is made economically possible by the energy densification. We note that it is in liquid form, but this doesn't undermine the analytical approach.

If you set down the range of options available in terms of materials, quantities, distances, potential products, implementation hardware, subsidies available, if any, you could generate a menu of options for Thailand, India or anywhere else. With a spreadsheet you can add cells for transport, fuel and other local variables. The output would be scenarios for viable enterprises.

At least one of the options would be the making of a bioenergy fuel for a well-suited stove.

Regards
Crispin

P.S. It is probably best to avoid making claims about extending lives through the mechanism of reducing the open burning of ag-wastes. That whole fraught exercise of claiming to be staving off the death dates of populations has too many logical and medical discontinuities to be believed. aDALY's are a low-logic densified form of B.S.
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Subject: Re: Off-topic: Biomass power and charmaking


Nikhil,

Thank you very much for this wide-ranging and, for all of your assertions to the contrary, extremely well informed answer to my rapidly knocked off comments.

In general, it is clear that we belong to the same camp. I, too, believe that biomass power has an absolutely central role to play in dealing with the issue of the complete, productive, efficient and sustainable use of crop wastes (broadly defined). That said, we still have differences.

First, the failure of the biomass projects in the Indian Punjab follow the same lines as the failure of biomass power in central Thailand: the initial dependence on rice husk. It is such great looking stuff. Looks cheap, easy to handle and abundant. Problem is that when you look closer, you see that it is already a marketed product (bricks, tiles, cheap pottery) and has a huge upside demand potential (especially in the cement industry). In Thailand, prices went from 200 b/tonne to 1,400 b/tonne and the power plants shut down.

The trick is to find a true waste feedstock. This is where I
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