Converting an LPG cooker into a biogas one

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And it’s not hard!

I bought two burners, the small one that you are supposed to fit directly onto the LPG cylinder, and a bigger, two-ring cooker that you connect to the LPG cylinder via a hose-pipe.

The small one cost 450 Ksh* (but I got it at 430, because the mzee liked me and my biogas idea). Converting it turned out to be very easy, and was done already on the bus ride home, while being tossed from side to side in the seat, because of those roads around Mombasa. It turned out to have a valve inside it for reducing the pressure, that could just be screwed out with a spanner, which I had luckily just bought one.

Pressure reducing valve that can be screwed out

This is where the valve was. Now the hole is much bigger.

Later, I connected the burner to my hosepipe by heating up the hosepipe and screwing it onto the threads of the burner, where the cylinder would otherwise be. I had put thread seal tape on the threads, and I secured the joint with a hose clip.

To hold the burner in place with the sufuria over it, I tried putting the burner inside an old and broken charcoal jiko. The knob for adjusting the height of the flame was sticking out through the hatch.

This construction worked ok, but even after taking out the pressure reducing valve, this burner still had quite some resistance in it, which meant having to put many stones on the digester to get enough pressure, and if too much pressure is added to the digester, it starts leaking slurry…

Add stones and children on top of your digester, to desired pressure.

One way to further reduce the pressure in this kind of burner would be to take away the knob for adjusting the flame, which can just be screwed off by hand, but of course, being able to adjust the flame is also very practical for cooking! And although it could be done by adding a valve or a tap to the hosepipe, this is not a great idea, because it could easily be too crude to be practical. So despite the ease of converting, I ended up not using that one so much.

The other cooker was a GoGas 2-ring cooker which cost 3’400 Ksh. (I got it for 3’200.) Adjusting that one was a bit trickier. At first when I blew into it, I thought it had a low enough resistance already, but when I tried to light the biogas with it, it’s like there was no gas coming out at the ring. Yet I could hear gas flowing!… I tried and tried to look for where the gas came out but didn’t find it. In the end I asked my friend Sammie to buy a cigarette and blow smoke into the hosepipe, so that we would see it coming out. Though not a regular smoker, he agreed to be the hero of the day and do it!

That test worked and we could now see that the gas was coming from the joint between the hosepipe and the cooker. I just hadn’t tightened the hose clip properly!… I felt really stupid.

Once the hose clip was now thoroughly tightened, it was almost impossible to blow through it into the cooker. It was clear that the pressure needed was much higher than what we could achieve from the digester. So I took out my screwdrivers and dug into the construction, looking for a valve. When eventually I found it, it didn’t look at all like that other one, that could just be screwed out. This one was actually a part of the piece that contained the air holes for oxygen supply, before the gas was let into the ring. What to do now…?

Well, I tried a piece of scrap metal that I had bought a few days earlier for a different purpose, and by sheer coincidence, it fit almost perfectly! Of course it didn’t have the threads the other piece had, but with some cloth stripes and Karlssons Klister (Swedish multipurpose glue), I managed to fit it in the cooker, and voilà, the gas burned highly and brightly! 🙂

Later, I took that original piece, that I had removed, into Mombasa town, and had an engineering workshop drill it open for me for 150 Ksh. Instead of that tiny hole that was there at first, it was now a 4 mm hole. I fit that piece into the other ring of the cooker, and now that flame burned even better than the first one. I’m guessing that it is the mixing with air in advance that improves the flame.

That cooker has now helped me many times, and improved my quality of life! I’ve cooked on it when I only needed a bit of fuel, so that lighting up the charcoal jiko would have been very wasteful. I’ve reheated tea and other leftover food on it. I’ve heated so much bath water on it! Before, if I wanted hot bath water, it was only available after meals, when the jiko was still hot after cooking. But after the evening meal, I was too tired to want to shower, and in the morning, I could as well wait a bit and shower cold at midday which is indeed very refreshing, unless I was going somewhere early. Just before supper on the other hand, I would have loved to have a warm shower, so that I could then just eat and go straight to bed clean! Now that was readily available to me. 🙂

Later I have seen low pressure biogas cookers that are originally made for the purpose. The biggest difference is that they have more and much bigger holes, so that they spread the low pressure flame better. A 2-ring cooker goes for around 6’000 Ksh. I guess if you have the money, you might find it worthwhile to invest in that. But otherwise my cooker at 3’200+2×150=3’500 Ksh will also help you!

Original biogas cooker sold by Kenya Sunrise Eco-Energy,

And then finally, of course we have the juakali ones, if you’re on a slim budget:

Just remember that biogas mixed with air can explode, so stay safe, alright! 🙂

*100 Ksh (Kenyan shilling) is roughly USD 1

Like a clockwork

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The digester that I started up in my last post has worked like a clockwork! Like a schoolbook example!

So I filled it for the first time on Saturday two weeks ago. I used super fresh cow dung and very old water. On the 3rd day I started feeding it a bit, waited one day, then fed it a bit more, then every day and then twice per day, although I skipped some times when I felt I didn’t get the time. Every day you could see the gas storage in the top of the digester tube getting more and more inflated…

After one week and a day, on Sunday, the gas storage was full. I let it out without burning it, in agreement with the safety recommendations in my own thesis. This is because if somehow lots of oxygen has managed to remain somewhere in the system, and mixed in the right amount with the biogas, this could cause an explosion. It’s not likely that oxygen would remain, because some of the microorganisms involved in making biogas can consume oxygen, and prefer doing so if it is there, but just to be on the safe side. Besides, the gas probably wouldn’t burn anyway, because there would be too much carbon dioxide in it. When there is oxygen present, the end product tends to be carbon dioxide.

The gas smelled like the worst fart you’ve ever felt, plus some… All the kids were helping me squeezing the gas out, but everybody kept moving away from where the gas tap was pointing, so in the end we put a rock there instead. All the grownups left the sight completely.

Only two days later, the storage was full again! So you see, the bacteria had adapted and were getting the speed up. The kids helped me squeeze again. Saidi said it smelled a little bit different, and I guess I wasn’t quite as nauseated, but oh, it still smelled bad… Lots of H2S!

Two days later, and the digester looks like a balloon, ready to burst… It’s now 1,5 weeks after startup. So I decide to try and light the gas for the first time. Jiko man has not been reachable on the phone for a while, so I’ve improvised the simplest possible device just to test if it burns: It’s just a thin metal pipe that I put inside the hose pipe and tightened with clips and glue. And voilà, the gas burns!…

Oy, those moments of satisfaction, after months of planning and preparing! 😀 It’s like the whole household here lit up with the excitement. The gas burned with a beautiful, blue flame, sometimes a bit pink or orange, without any smoke and no smell either, except when the flame blew out now and then.

Ok, remains only to get a jiko sorted, and then we can start cooking for real. But already the next morning, I improvised again, so that I could warm my bath water with my biogas… And it was quick, mind you! (Which was good, because holding the sufuria (pot) like that kind of hurt my hands…) Another moment of blissful satisfaction! 🙂 

Things coming together

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Yesterday morning, I woke up by myself when it was still dark, thinking:

‘Where is that cock? Has it overslept . . .?’

I checked the time, and it was 4:25. About 5 min before the cock normally crows. So after a few minutes, it did crow. I nodded in satisfaction, and went back to sleep. Again and again I heard it and went back to sleep, until the sun was well up, and I woke up fully rested! We have finally reached harmony, me and the cock. 🙂

I think I’ve figured out why we have so much sleeping problems in Sweden. We’re just not tired enough! Of course this is partly because of what the experts also say, that we live too inactive lives, too stationary, too little physical labor and activity (and too much looking at screens). But I think it’s also because we just sleep too much! And too quietly! Too undisturbed! . . . So when something does disturb us, our bodies are probably quite happy to wake up. We were developed for a life with disturbances, after all . . .

Preparing my morning bath. I like those pictures best, that somebody takes of me when I’m not aware. 🙂

Though I’m also feeling strong for another reason. Yesterday, I started up my digester, with fresh cow dung from a nearby slaughter house! 🙂 We filled it with around 60 l of cow dung and 60 l of water, that had been stored for long, so that all the chlorine would be gone from it. Chlorine is, of course, bad for the biogas process for the same reason it’s good for drinking water: It kills microorganisms! No bacteria, no biogas.

Already today, the digester is showing some significant swelling . . . That dung must indeed have been very fresh! 🙂

Digging my digester pit. The purpose of the pit is both to give the digester a nice shape to lie in, to reduce stress on the material when it’s heavy with slurry and swelling with gas, and to offer some temperature stabilization.

Inventor and business talent Seif has finally arrived to the spot.

Seif contributes to the design, by adding a support to the pit, so that the weight of the digester doesn’t block the inlet and outlet. Sasha helps testing their strength and possible use as balance practicing equipment.

Filling the digester with water, just to test for whatever! . . . How much water it takes, how heavy it gets, if the pit holds, if it leaks . . . though nobody seriously believed that last one! But I stood on it, just to confirm. 🙂 (In fact, that was when we were trying to get the water out again . . . It was not a very effective method.)

We were filling it using the siphon principle, of course.

Isn’t it great when science just works? The crazy grins of two technical nerds in action . . . 🙂

Trying to get all the air out

Emptying it afterwards. This digester is just a tiny one for experimental purposes, so it wasn’t TOO hard . . . for three people!

Building a roof to protect the digester from the sun. Sasha helps untying the knots that uncle Kupata has just made.

There are some things that only happen to female engineers. In the middle of having my roof built, I’m called to wash the dishes! Hey, I’m busy here! . . . I’m watching my structure coming up!

Well, there are some things that only happen to male engineers, I guess. Being called into a war, perhaps . . . Actually, washing dishes is not bad.

Those slender rods are actually sisal flower stems. Very strong, yet very light. Yep! In Africa, there are flowers that you can build houses with.

This cover is just temporary. It will be coconut tree leaves later. Which is more of a grass than a tree . . . Because, you know, in Africa, the grasses grow high like trees. Yep.

I tried using a jug for the dung but it didn’t work, so I just used my hand instead. It was fine, really! Fresh cow dung smells healthy and organic, and feels like warm, wet grass. It was only afterwards, when the smell didn’t leave my hand that it became a bit bothersome . . . I recommend a small shovel, and possibly gloves, for this work!

Two hand-fulls of cow dung, one jug of water.

The sun still got to it in the afternoon, but this will be fixed.

Can you see how it has risen . . . ? 😀

Stay put for the exciting continuance! 120 l was even less volume than we expected to fill it with . . . but perhaps we’ll be able to cook at least tea with it next week?

Without water, life is hard!

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Yesterday morning, Delina woke me up at 4:45 to go and fetch water with her and Mnyazi, since the tap had been dry for several days and all the water was over. It was great! We found grandma Fenny already at the well, filling those jericans of 50 l. We worked hard as the sun came up to bring them to our house, which, luckily, is less than even 100 m from the well.

A 50 l jerican of water though, I can not get up on my head! If I got it up, I could hardly correct it if it would start to fall, and it would surely break it I dropped it. Carrying one by that hand hurts your back. Carrying two… well, grandma Fenny does it, but it’s hard work indeed! So me and Delina, we took three between the two of us – one on each outer hand and one that we shared in the middle. Turns out the weak link was the left hand… None of us could carry far without dropping the one we carried alone with our left hand! (It occurs to me now that we could have both had our left hand in the middle, so that we would be facing in different directions, and then be walking sideways on a line…?) Anyway, the sun came up and water was there! It was very satisfying.

Delina asked me if I was tired “ama bado?”, or not yet. “Bado!”, I answered, not yet! They laughed. Delina asked if we go one more time, her and me, and I said ok. They laughed again but said it’s not possible, because the well was dry now anyway. The water was over. Which was ok, coz we now had plenty.

The next morning, Delina woke me up same time. I did not hear what she said, but didn’t need to. I just got up. But when I reached the well, as Delina was still cooking the snacks she sells in the school where she teaches, grandma shook her head and said the water was already over. And she had been there since 4:15! Already then, it had been gone!

“Nakuambia, watu wamelala hapo, people they slept here at night!”, she said. “You better go home and sleep again.”

So I went back home, although of course I would not sleep again now as day was breaking. Grandma stayed to keep harvesting the little trickle of water that filled the well, as she had been doing for 1.5 h…

As I reached home, I told Delina there was no water, and she exclaimed:

“Oh! People they slept there last night!”

Perhaps people really did sleep there, by the well…?

So as I came back from picking Sasha at school, I immediately went with the children to the well to see if there was water. Several people were already sitting there harvesting the trickle, in the darkness because the sun had already set, but there was no water. We went to another well, which is still only around 2–300 m from home but it’s up a hill and down a hill. I had seen people getting lots of water there in the morning when our well was empty. But I could see already from a distance that there was nobody there, so that did not raise hopes… and as we reached, the well was of course dry.

So after an early supper, I put the kids to bed and we went to sit by our well to wait for the trickle. Again, there were many people there… It must have taken us over an hour, and yet we probably didn’t get more than half the amount we had fetched the previous day… Not so satisfying anymore! But what can you do? As we sat there, Delina shook her head and said:

“Without water, oy… Life is hard!”

It’s not even drinking water in the well. In fact, when it’s scarce like this, it’s quite dirty. I wonder what these people drink? Since the food poisoning both me and my youngest, Sasha, had last time the tap was dry for long, I’ve been giving bottled water to the kids when the tap is dry. They store tap water for drinking separately here, but after a few days, I think it’s still not great to drink…

I also wonder what those wells are really about!… They’re not boreholes! Down there, there is a huge pipe which they’ve told me is the main tap water pipe… They’ve also said the water from there is, in fact, tap water, but they don’t drink it, because that well is open all the time so you don’t know what has come into it… But why would the water company want to leave tap water out like that? It’s obviously not just a broken pipe (though I’ve seen places that look like they are that too, and people collect even that water, but) this is a properly cemented place with two hatches on top to lift the water up…

It’s weird. But we need to shower, wash clothes, clean utensils, clean our house… so what can we do? We go to that weird well! At least, I’m getting a full body exercise! 🙂

And the reason me and Sasha were so late from school was that we had a cup of tea and a very fruitful conversation with the chief of this place. He knew of a slaughter house maybe 2 km from here where I can probably get cow dung. So with any luck, I’ll be carrying a small bucket of cow dung on my head for 2 km every morning soon! 🙂 To feed my tiny experimental digester, of course. I look forward to that!

And one of the import agents found by googling gave a price that is at least only 2/3 of that other one… That’s around USD 900 for 3 digesters. It’s still high, but it could maybe be done, for a first attempt… Were rolling! 😉

And now, it’s past midnight and I’m up writing. It’s because after our disappointing water adventure in the morning, I had some light food poisoning again, and then I went back to bed and slept until 2 pm… My day rythm is completely up! But I’ve taken my sleep medicine and now I’ll just publish and try to sleep. For 5h, until my alarm rings again. Or maybe 4h, until the inside cock crows… because one of the chicks have grown up to become a rooster. I’m not thrilled about it!… But I’ll get by.

I’ll try to add pictures tomorrow, but right now I haven’t really taken any. So good night!

Bumps on the road

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“TIA – This Is Africa”. . . (A line from the great movie Blood Diamond.)

The house that was being built and that we were supposed to sleep in came to an abrupt halt when the money got finished. It reached around halfway. . . says the same person who originally said the money would be enough. . . So. . . don’t be surprised if it’s more like two thirds or three quarters remaining still! She’s a lovely woman by the way, with so many talents! 🙂 Money just not being among them! (Nor is time. . .) TIA

My colleague Seif, who was supposed to be my most important co-worker, has not yet made it back from Zanzibar. He was supposed to come around the 1st of September, but again, money was missing. TIA

There is somebody in this house who has an alarm set for 3 am and 5 am to pray. Another person has an alarm to get up at 4:15. From there there’s usually noise going on, from the kitchen etc. My alarm is at 5:30, but usually by then I’ve been awake since 3 am anyway, since me, being such a spoiled Swede, with such weird, unnaturally quiet habits, I can’t just go back to sleep like these people have a magical talant for. . . 

If you think they go to sleep early with that schedule, think again! At 10, 11 and sometimes even 12 pm, there’s still loud noise from TV and radio in the house. It happens that they fall asleep with the radio on at high volume, and I’m the only one still awake. . . TIA! I’ve taken a habit of always sleeping with sleep medicine.

I’m telling you, there is something we do wrong up there in Sweden when it comes to sleep. Because we have sleep problems there that people have never heard about here. . . TIA!
Of course they nap in their seats or the sofa in the afternoon, and I do that too. But me, I fall asleep too deeply! Often half my working day goes that way. . . Though probably I will adapt with time.

Oh yeah, the welder! One day I just stopped chasing him and I have not heard from him ever since. TIA. Perhaps the magic of my radiant white skin faded after some time and with that he lost interest. . . ? I have a meeting with another “jiko man” tomorrow. (A jiko is a fire thing for cooking.) This one is supposed to have the expertise for making biogas cookers.

Oh btw, I also want to stare at white people now, if occasionally I see them. . . 🙂 They’re so freakishly white!!. . . I mean, it’s ridiculous!!

I was just about to import 3 digesters of 5 m3 to start with. But all of a sudden, the price for importing them skyrocketed!. . . The agent says it’s much more expensive to import small volumes than big. But I HAVE to import small volumes to begin with! And I can’t sell at a loss!. . . So now I’m looking for a new import agent. I’ve realized you don’t HAVE to do it the African way, through contacts! Google works, even here. . .

And now that I have showed my tiny digester to a number of people, I want to start it up! 🙂 I’ll keep you posted!

Now, the story in pictures:

Yes, I can carry a jerican on my head!. . . If I support it with one hand! :p

Kenya banned plastic bags! I’m so impressed. . . Here are some of the results:

Reusable shopping bags sold in the supermarket. Yes I have mine!

Street food being sold in paper cones. Why not! Just like in Sweden of old.

I had a picture of two young men selling a variety of reusable shopping bags in all colors in the street of Mombasa. I was going to name that one New business opportunities, but it’s like I lost it. . . Oh well!

Who thought I would find myself walking around in skirts and scarves all the time?!. . . It’s very comfortable, you know! When the temperature is around 30 centigrade and the humidity 100%. . . (And no, my waist bag is not normally open! But I had just removed my phone to give to Sasha, who wanted to take my picture)

And it protects you from the sun, too! Though this is becoming less and less important. . . Btw, I’ve actually managed to avoid getting burned, all together! 🙂

Felix giving his new brother a hair cut. More enthusiastically then well, though. . . But with some subsequent adjustment. . . Yeah!

Getting settled

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Today (read “yesterday”) Felix started in his new school. He was super excited! 🙂 We have gone around to three different schools just to see the difference, and to ask which ones will force him to cut his hair and which won’t. He has given up his previous school, his friends, his country, his culture and everything that is familiar to him without much fuzz, but if anybody tries to take his mohawk, that fight will go all the way to the finish!…

A proud and happy Felix at lunch, his first day in school

Only from going for these school interviews, it is also very evident to me that there is a stark difference between one school and another here. We went to one public school and two private ones. The public one was of course the worst. No surprise there really – everybody had told us so – but it’s different when you see it for yourself. Their attitude seemed to be “Do you really HAVE to bring us one more student…? And this one doesn’t even know Swahili and only a little English, it will be lots of work for us!”. On the whole, I got the impression that they felt that children are a nuisance that only needs to be kept in check as much as possible.

But the most expensive private school was not the best! It’s probably good enough, it was mostly the fees that scared me away. But later I also heard that the head teacher there has said that he keeps the fees that high so as to make sure he only gets “the right people”… Hmm. I’m not sure the right people for him is the right people for us!

But the middle option really impressed both me and Felix! Novel Junior School. I loved the head teacher there, Naomi N. Kioko. She talked with us a bit and Felix did a test with one of the teachers, and towards the end when I said I think Felix will catch up quickly what he lacks in language and hand writing, she said, with a wink to him:

“No, I’ve seen him. I know he will!”

Novel Junior School in Miritini

Me, young Sasha and the head teacher madam Naomi Kioko in her office.

She seemed happy to have the opportunity to nurture Felix’ talents and enthusiasm, and make sure he gets the attention he needs so that he can develop them well. Like she is in it for the passion, not for the money or anything else.

Otherwise the project is moving, “slowly by slowly”. I’ve come in contact with a woman in Nairobi, Joyce Wango, who installs fixed dome biogas digesters and is interested in venturing into tubular digesters. I’m planning a little tour with my tiny biogas digester, where I will visit her, the NGO Goshen that I’ve blogged about, Polycap and Samuel from my biogas club in the Nyasanda design project, Orongo Widows and Orphans Center, and all those people over there in Western Kenya where I’ve worked before, to see who is willing to work with me and what each one is willing to do. I will also try and get hold of some people that I have lost the contact information to!

I have ordered a biogas burner from a local “fundi”, a welder. He has seen the digester and the site and seemed interested in long-term cooperation. However he seems very… Kenyan… in the sense that he never shows up when he has said he will. In fact, he hasn’t showed up at all in a while! Well, we’ll see.

Good night, for now!

Fresh from purchasing school uniform

Second day of school, at 6:45 am. Breakfast on the way! From left: Felix, Sasha, Mama Fenny, Fenny and Esther.

The intended site for the miniature digester. My house on the right. It says

The intended site for the miniature digester. My house on the right. It says “Danger” on the electricity pole right there, but. . . that’s ok, isn’t it? And I think a small latrine could fit on the other side of that pole, just for me and my kids in the beginning. . .

Relaxed African village life. Just resting a bit while waiting for the members of the “chama”, that is the microfinance group, to arrive.




First days of the new project/adventure

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We’ve landed in Mazeras, just outside Mombasa. So the plan was to go to Zanzibar at first, because of political tension, and I actually bought a ticket there at Nairobi airport. But I cancelled my ticket and got my money back (Kenya Airways! Still the best return policy you’ve seen in an airline company…) when it turned out to be very expensive, plus everybody convinced me there was not going to be any political violence this time, and even if there was, it would not be in Mazeras.

We’re currently sleeping in a room in “auntie Feni’s” house, the mother of my friend and co-worker Esther, cousin of my teammate Samseif. Today however, we started repairs for a room in another building on the compound: It will be enlarged, the floor will be cemented, windows will be put in, and when it’s done, I and the kids will sleep there. We will even get furniture from Esther’s old house in Mombasa, which she is planning to move out of, so that she also stays here in Mazeras. Our household thus consists of: Auntie Feni, her two grown children Esther and Suma, Esther’s 11-year-old son Saidi, Sumas wife Delina and their 7-year-old daughter Feni, who only lives here part-time, and the rest of the time with her other grandmother near her school. Plus me and my kids, Felix, 7 years, and Sasha, 3 years.

The arrangement is perfect, since it means we all eat and live together, meaning that I and the kids are constantly exposed to the Swahili language, authentic Kenyan food and just Kenyan life in general! (I asked Felix the other day if it’s true what I had predicted, that Kenyan kids are more fun to be with? He said it’s true! So I asked how so, and he said: “They come up with much more fun games to play all the time!”… I’m gonna stick with my theory that this is because Kenyan kids are left alone to play (and sort out their own conflicts) much, much more than Swedish kids. Kids have much more fun if adults just leave them alone…!) Last night, Sasha was really eating his ugali well! 🙂 Even with the green vegetable stew that was served with it. Myself, I have formed several correct sentences in Swahili, and picked up one or two when they speak with each other… It will get better!

I have unpacked the tiny little biogas digester I got with me from Sweden. It is, of course, adorable! It’s made as a tube type, though it’s so short to its width that it might work more as a tank… but without stirring… (The manufacturer has convinced me that a tube digester is better off without any stirring at all, unlike what it says in my thesis.) Today, I bought connections for it, to attach the gas tube. Thank God for standard pipe and thread sizes! I’ll try to use a 3/4″ water pipe, since it’s there already. I’ve also made arrangements for free cow dung. The only thing that remains to get now is some kind of burner for the gas, and we can start up the adorable little thing! 😀

Oh, and I seriously need to print some business cards that I can give out. Interest in my product is as high as ever… Remains only to see if they’ll actually buy it! 🙂

Picking coconuts

Sasha helps Esther and Delina cook chapatis

Esther supervising the building of our new home