Metal

The TChar(tm) stove is a TLUD stove that lifts off at the end of the gasification stage to drop the charcoal into a T-base(tm): a charcoal stove to continue cooking with the charcoal created or a quench base to save the charcoal for biochar or other use.
Download Part A of TChar Technology for Cookstoves at:
http://drtlud.com/

tractor jack briquette press

I was finally able to complete my tractor jack briquette press on a recent trip to Haiti. I started it in the spring but had to load it into a shipping container in May before I could complete and test it. It uses a 3 1/2 ton (3.2 tonne) 48" (122cm) tractor jack. About 30" (76cm) pressing cylinder, 3" (76mm) diameter PVC . Two 3/4" (19mm) threaded rods for tensile members. 4' x 6" (10cm x 15cm) rectangular steel tubing base. Shouldered hole in bottom to hold cylinder base while allowing briquette ejection. 4" x 4" (10cm x 10cm) square steel tubing top. Wood frame. Removable steel plate covers ejection hole for pressing.
The long stroke allows for production of multiple briquettes at once with plastic disc spacers.
The current design produces pucks. Holey briquettes are possible with some modifications.

Cecil Cook with Technoshare, November, 2011


Baseline Study of the Socio‐economic Patterns of Charcoal, Wood and Stove use in greater Lusaka, Zambia

Some highlights:

  • Previous stove improvement projects have failed to properly appreciate the central role played by one and two person tinsmith enterprises that produce and sell ordinary mbaulas at very low prices. The tinsmiths of Lusaka constitute a well distributed network of producers and sellers of ordinary mbaulas fabricated from scrap sheet metal who conveniently service all the major markets and townships of the city.
  • In addition to underestimating the multiple competitive advantages of a well distributed network of tinsmiths who fabricate and directly sell a charcoal stove that everybody knows how to operate, previous stove improvement projects failed to appreciate just how poor the bottom 2/3rds of the Lusaka economy really is and how little money low income families are able to save from their daily and weekly income for the purchase of a replacement mbaula when the old one finally breaks down. It is the initial retail price of an improved stove, not how much money it will save a household during the course of a month, that determines whether they are willing and able to spend two, three, four or more times the K4 000 to K6 000 for a 20cm ordinary mbaula. The ordinary mbaula is the industry standard. Every household without access to firewood, no matter how poor, has to pay out at least K4 000 once or twice a year to purchase a replacement mbaula.

Cecil did a good job of discovering the buying patterns in households of at least 3 different income levels, and uncovered that the ordinary (less effecient) Mduala stove has great traction among ordinary lower income members of Lusaka Zambia because the stoves work as expected, and they are inexpensively produced by local stove manufacturers.

He has also shared with us some of the highlights of the report in the attached pdfs.

On a recent trip to Haiti I was finally able to construct my CharBowl(tm) charcoal stove. It uses two nested stainless steel bowls (5 quart and 8 quart (4.7 liters and 7.6 liters))for durability and reflectivity with castable insulating refractory between them to reduce conductive heat losses. It has a 6.5" (16.5cm) dia cast iron grate for durability. It has a secondary air pipe to reduce CO emissions and increase heat output. The secondary air outlet pipe is 3/8" (10 mm) nominal (ID 0.493" 12.5mm; OD 0.675", 17mm) black iron with a Tee fitting on top to keep charcoal from dropping into it. 3/4" NC 10 (19mm 2.5) machine threads were cut over the pipe threads. This allowed the use of a split nut and flat washer inside and outside the bowls to hold the bowls together. The elbow is 3/8" to 1/2" . The inlet pipe is nominal 1/2" iron (ID 0.622" 16mm; OD 0.84", 21mm). The bowls sit on a stock pot base for stability and primary air control. (I couldn't get my hands on the stainless pot I really wanted to use for the base. I'm planning to build another with such a base now that I'm back in the States.)
I hope to get some testing done on my second prototype.
It can be used as the base of a TChar stove.

Alexis Belonio, Victoriano Ocon, and Antionio Co

Garbage-In Fuel-Out (GIFO) Project,
Suki Trading Corporation, Lapu-Lapu City, Cebu, Philippines

This project is a cooperation between Suki Trading Corp. and Kanvar Enterprises and the Centre for Rice Husk Technoloy (CRHET).

Paal Wendelobo, October, 2011

The Peko Pe TLUD project in Zambia is going well.

Paal describes it best:

" The main principals for our projects I will call it community based participation both for fuel and for stove productions. Utilization of local resources with other words.. The Peko Pe is designed for production by local tinsmith with the tools they might have. They only need a template and a model; they have the knowledge how to make it.

" First of all we discuss the need of changes, and then on the fuel side we start up with registration of alternative biomass for fuel for briquetting, energy forestry for fuel production. We always start with the fuel .to be sure there is sufficient quantities and to an affordable price.

"The charcoal business, which represents about 15 % of the adult population, has to be involved from an early stage of the project. All kind of activities on the household energy sector will in one or another way have an influence of their business, and with biochar we don’t know what will happen, but that is one of the ting we will try to find out. Any how for the charcoal business it is just to change from charcoal to alternative biomass for household energy.

"The energy loss by production of biochar for soil improvement is almost equivalent to the energy needed for the farmer to cook if you include the African way of thinking time is coming not like by us time is running That is a big difference. A household need about 2,7 kg charcoal a day for cooking. Form about 10 kg of dry wood you will get 2,7 kg of charcoal for one day cooking and no biochar. From .10 kg of dry wood you will get 10 kg of woodchips and that will be for 2 ½ day of cooking into a TLUD-ND. and about 2.7 kg of biochar. The pilot project will tell us if this is right or wrong."

" A common Miombo forest in Africa will give about 3 ton wood per ha a year. 3 ton of dry wood will give 800 kg of charcoal. A household of 5 consume 2-3 kg charcoal a day or about 800 kg a year. To produce 3 kg of charcoal you need 10-12 kg of dry fire wood in a common kiln. That will give one day cooking on a charcoal stove, and almost no biochar. 10-12kg dry chopped wood will give 3 days of cooking on a TLUD-ND or another FES and 2.5 kg of biochar
Energy forestry using just the sprouting every year can give up to 10 ton wood per ha a year, easy to cut to appropriate fuel for TLUD-ND’s or other types of FES. By adding some biochar to soil of bad quality 20-30 % increased yields can be obtained, which will give more food, more household energy, more jobs, better economy, better health for women and children and saving the forest. It can probably be as simple as this and is that not some of what we are looking for and need?
We know some changes have to take place on the household energy sector and we have to start somewhere. Why not start with small scale farmers on sandy soil, and from there develop the new household bio-energy strategy for developing countries. Probably also with the charcoal business, they have the whole infrastructure intact and can easy change from charcoal to alternative biomass like chopped wood or pellets from agriculture and forestry related waste. "

Quoting "Prof. S.C. Bhattacharya" :

Dear all,

I would be happy to share some publications arising from the following
activities at the Asian Institute of Technology:
1. Sida funded Regional project: An information package (including
construction details) on biomass briquetting machines developed in a
number of Asian countries and design of natural- cross-draft gasifier stoves that can operate continuously is available. The briquetting machines developed
were improvements on standard screw-press heated die design. Cross-flow
gasifier stoves were designed for different sizes; these do not need any
blower and can operate continuously without any smoke.

The briquetting and gasifier stove work I mentioned was carried out under a
Sida-sponsored project at the Asian Institute of Technology (AIT). The
project involved researchers from 12 national research institutes of six
Asian countries, e.g., Bangladesh, Cambodia, Lao PDR, Nepal, Philippines and
Vietnam. The findings of the project were disseminated through national
dissemination seminars in these countries; published "Technology packages"
were distributed widely in the region and are still available for
downloading from the project website. We organized technology transfer
workshops, in which a number of NGOs form the region were invited, on most
of the technologies developed.

(There is no restriction on distribution of the technology packages.)

Unfortunately, the link of the project is not working due to heavy flood in
Thailand; AIT appears to be still under 2 m of water.

2. GTZ funded project on Biocoal: We used the term "Biocoal" (rather than
"Biochar") for charcoal produced from solid organic residues such as
agricultural residues and waste wood. The findings of the project were
reported in a book titled "Biocoal Technology and Economics" by "Regional
Energy Resources Information Center (RERIC)" (email:enreric@ait.ac.th).

The chapters of the 495-page book were:

  • 1. State of the art of biocoal technology,
  • 2. Biocoal technology: A comparison of options and recommendations,
  • 3. Carbonisation of sawdust briquettes,
  • 4. Laboratory-scale batch carbonisation selected residues,
  • 5. Cost and availability of selected residues in Thailand,
  • 6. Characterisation of selected residues,
  • 7.Biocoal: Market requirements and Opportunities in Thailand, and 8. Economics of biocoal production in Thailand.

A few copies of the book are still available with RERIC. A number of
chapters of the book were summarised as journal articles; I will be happy
to
share some of these with interested persons for their personal use and
research purpose.

Other technology packages and published papers of the Sida project can be downloaded from www.retsasia.ait.ac.th. The biomass/stove group may be interested the package on drying, which includes a hybrid drier using solar energy and bioenergy from a gasifier stove, heat output of which could be automatically controlled by using a thermostat.

I also coordinated another regional project (Asian Regional Research Programme in Energy, Environment and Climate, ARRPEEC) funded by Sida in three phases during 1995-2005. One of the 4 projects of ARRPEEC was on biomass. Dissemination booklets of ARRPEEC and some of the papers published can be downloaded from http://www.arrpeec.ait.ac.th

Mussie T. (Lecturer at Mekelle University, Ethiopia), October, 2011

This is a Natural Draft Gasifier stove, that is designed with a central column of air that is designed to burn more common Ethopian fuels, e.g. coffee husk and saw-dust (cow dung binder) briquettes in addition to more conventional wood chips.

the air column is drilled on the surface so as to let additional primary air radially into the fuel at different stages to compensate for air clotting that can occur when run with small sized fuel as you go up from along fuel column. This helps the flaming pyrolysis from being air starved due to interlocking of fuel particles. In addition to that, closely spaced holes of relatively larger size were made near the top of the central air column to supply more hot post‐pyrolysis secondary air. The presence of two hot secondary air admission points is meant to supply enough air while keeping the stove short with reduced heat loss.

Once the stove has enough fuel, it is typically started with wood chips, or an accelerant to help the briquettes light, and then in all of the trials it burned without smoke until the fuel tank was filled with charcoal (typically between 60 and 90 minutes later). This is a biochar-producing stove, the stove does not efficiently combust it. Friability and the composition of the char depended upon the feedstocks.

For an excellent analysis of the stove, and pictures of the biochar, please see the included Report: Results from Preliminary Experiments Conducted on Multi‐level
Primary Air Entry Gasifier Stove

Hugh McLaughlin, September, 2011

I may have solved a design issue with the combustion of the wood gas in a TLUD. I call it the "Toucan Flair", which is a play on words (flair > flare) because the distinguishing feature is an axial tube providing "axial air" to the secondary combustion zone. This axial air source is coupled to the primary air source, which is controlled by a small fan pressurizing a plenum to support the two burners provided for the entire stove.

Additional "scroll air" enters in the riser above the ignition level for the wood gas, providing a concentrated region of combustion. Depending on how much wood gas is generated, as controlled by the degree of fan assist, the flames can be driven to the bottom of the pot, but the unit can also simmer as required (see photos).

This geometry basically turns the concentrator disk inside out - and make for a preheated expanding jet of wood gas, that is consumed by the excess scroll air. Axial and scroll are burner terms for air injected inside the fuel and provided on the perimeter of the fuel. The terms may well be engineering slang. However, the effect is significant, based on my comparison of the side by side configurations (Toucan Flair versus traditional concentrator disk TLUD).

Paul Olivier, September, 2011

Paul Olivier is working from Vietnam, and had put together a comprehensive pdf article explaining the benefits of using TLUD and other gasifier stoves to avoid cooking smoke and create biochar. Cooking Smoke is a major health problem in both rural and urban areas in Vietnam and many other parts of the world, and improved stoves that can also produce biochar can also help urban and rural people retain nutrients in their soils, and reduce pollution.

For more, please download the pdf: Biomass Gasification and the benefits of Biochar

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