I am interested in some photos thanks ... and also some more idea of what level/scale these devices operate at ... experimental or fully fledged etc.
I was also very interested in the other thread where you were talking about your garden shed and its dirty little secrets ... but that thread got a little derailed, so I’ll flag my interest here.
It’s not much help to you coz we’re down in Aust ... but we do have plenty of clay on our property ... and your comment ... “ If you have an acre of land set to grass, and two - three sheep on it, a house of 3-4 people and access to organic material ... “ also got my attention.
Hi
I will give you some detail here. We do have a couple of company blogs where more detail is given, but most the detailed stuff is hidden in a customer section and our research site which is password protected. We will be opening some of that up to a wider audience, but didnt want it completely public as the time taken to deal with spam etc is a nightmare.
Scale wise we operate like most companies who do both research and consultancy, we also implement systems but like most we dont manufacture the actual reactors as the cost of a plant to mold plastic etc is a non starter. Scale wise all new systems in most companies start at lab scale, volume wise depends on the system. Single reactor batch systems are normally around 1-3 ltr, the reason is both cost and safety. Generally if you can get a system working with lab glass on a small scale, then it will almost always scale up better.
So lab scale gives the best of all worlds, from a safety aspect if your working on a new system or if you mainly focus on the newer multi chamber continuous flow systems like we do, then safety is a big issue as your dealing with explosive and inflammable gases, its also harder to montor mid and full scale systems when your trying new things. Again if it works on lab scale then its more likely to work when scaled up.
The latest system we are working on is roughly going to be 5-12 ltrs lab scale, this is as large as we have gone so far and is about as large as normal reactor lab with several systems in. From Lab scale we build proof of concept system to get a good idea of full scale production parameters, for us this turned out to be our septic tank with several other chambers added. Normally you would aim for around 150 ltr upto 600 ltr, because we had the land and a Victorian brick septic tank, we got hold of some 'onion' type plastic septic tanks and added those.
The control part and pump house is an outbuilding, the tanks are 600 yards from the house so a safe distance. Total capacity of this system is nearly 4000 ltrs which is a small scale full sized type capacity, we used it as proof of concept and it got us our first 'job' in digestion.
The other part you mention is the ground battery system, this is with clay for best results as acidic peat dosnt seem to work well, most of it is no big secret and is based on Edison cell type technology. The clay is more of a electrolyte than anything, or so we thought...... If you want i will add you to a list of a people with access to the day to day data and information on it, its still very experimental and we dont really understand how it works yet. Your welcome to view the less private side of the experiment site, obviously some the info we dont give out in case we end up in position to patent it.
If you use a modern continuous flow multi chamber system for digestion, and add in decent insulation around the house etc, then home systems work and work well. An example being something like 3-4 1,200ltr onions or even IBC type containers (International Bulk Containers) the ones in a steel cage are cheap, you can build a system that would give you around 14 hours of cooking gas a day, but if you can feed it enough material (hence the sheep,grass and wood waste) then a family of four can get alot of energy from it.
Keep in ind this is a quick run down, you need to use it as part of a closed system, so things like evacuated solar heating panels and a storage system for both gas and electric (hence the ground battery). The biggest problem we were facing is sludge and how best to break down carbon sources like wood etc, recently both of these seem to have been solved, or more accurately those are the things we are working on right now.
In a batch system you empty after each batch and the sludge goes onto the field or whatever, this is wasteful so we designed a continuous system, the liquid digest-ate was fed into a large hydroponic system, if you take the CO2 from generator exhaust or the digester and inject ito the waste stream it feeds the plant roots. To get an idea how how successful that is, look up dutch planted aquarium systems.
The following is an example
What most have in common to get plant growth like that is CO2 injection systems, the CO2 is dissolved into water to form Carbonic Acid. Carbonic Acid is a rich Carbon source that has extremely high bioavailability to plants. If you use it on certain hydroponic systems it works with the roots of terrestrial plants just as well as the aquarium above. What most people dont understand is many of these aquariums like above, contain plants that in the wild are only totally submerged during the rainy season etc.
Very few aquatic plants actually live fully submerged all year, although the above pick has a 50/50 mix by the look of it lol. Anyway once you understand that you realize that feeding Carbon to the root system has alot of advantages over feeding it to the leaves via the air. If you air feed CO2 then you have to be exact in temperature and humidity, the plants dosnt feed constantly via the leaves, the stomata on the leaf closes alot to conserve water etc, this is widely affected by temp and humidity.
However the roots can feed mot of the time so the uptake of carbon is much greater. The downside is if you feed high amounts of carbon then you have to make sure the plant is supplied with enough other nutrients to use it. This is where the digestate comes in, the plants strip out the nitrates and the other macro/micro nutrients at a very fast rate. If you cycle the water from the last stage enough times around the hydro system, you get water that is depleted in nitrate and minerals. Where i live this is highly valued as we live in a nitrate sensitive area.
So SEPA which is our Scottish Environmental Protection Agency, are keen on these systems as the discharged from the digester ends up as depleted water which is simply released like normal. Normally to get the most from these systems, you use a high value crop/crops so things like tomatoes or strawberries, some grow exotics like Orchids etc. You use any waste heat from the electric generators or pre treatment systems to heat the poly tunnels or green houses.
The idea is to waste nothing as far as you can, this maximizes the return on the system, The problem we had with the first continuous feed system was a very slow build up of sludge, this is spent organic material and dosnt produce methane anymore, it can be microbialy broken down into CO2 eventually. But then you can start to poison the system with too much CO2 in the digester, the breakthrough was microbial cells, this sludge in the new system is passed to a final chamber, where with some magic and microbes it is rapidly broken down into CO2 and also produces electricity at the same time, its not huge amounts of electric, but enough to run the microbe cell and a little extra.
The real benefit comes from desludging and producing CO2 which can be recycled into the system or we are looking at a system where it would mixed with Hydrogen from electrolysis from wind turbines, passed over a catalyst and produce Methane, this is the NASA mars research area (roughly), we are looking at some slightly different and for us the real payday with this system is a by product, if we can get it to run properly then the microbe end cell would make more money than the entire system on a daily basis, but its early days at the moment with side of it.
Currently we have recently been invited to put forward plans for some digesters in southern Scotland, Cumbria and Northumberland, our local authority has teamed up with another one. On top of that they are forming a group with the local water company and wanting to trial a digester at a water treatment plant, this is where our bio diesel from Fat bergs comes in. Most of this has happened in the last few months, it took a while to get a continuous system built, banks wouldnt lend and we had to self fund.
Then we had a few people come and look at our home system and got an offer to build our first full scale plant, its fairly small but it gave us the 'IN' with the local authority etc and proved our system worked and was alot more efficient than standard. I cant take all the credit by a long way, i have a business partner who has helped massively to get this off the ground, i have had access to some university resource for sharing information etc and now that i am doing a semi part time masters in Environmental engineering that has also helped alot.
So maybe 3-4 years of work and god alone knows how many years i messed in my dads lab!! Is just starting to pay off, it isnt something i have mentioned that much on here until recently, most regulars where aware i 'dabbled' with bio fuels but few actually knew just how far into it i was. It was kinda fringe a few years back so most people into it kept quiet, alot like being a matchbox collector
. You do it and love it but dont really tell people about your hobby lol.
I hope that helps you a bit, i will pm you a log in when the new experiment blog and site is ready. It will give you more info than i can put here, although the new control system stuff will be posted here as its more relevant with electronics.