Monday, May 03, 2010

West Africa Cashew By-Products Project Assessment Trip

In late March ATDT representatives were sponsored by the ACi to visit West Africa to observe the end of the 2010 cashew harvest, and see first hand what the issues surrounding cashew byproducts are in this region. We flew into Accra, Ghana to meet the project organizers then planned to quickly head out for Burkina Faso by plane – but two days of late harmattan (sand storms) kept us grounded so in desperation we hired a car and driver and spent the next 2.5 days speeding the length of Ghana as we tried to make up for lost time. We took the opportunity to visit Ghana’s largest cashew operation, MIM Cashew, where we received an excellent introduction to cashew processing from managing director Lars Wallevik – pertaining to byproducts, they are just getting ready to introduce a cashew apple schnapps (very modern equipment), and while they burn some cashew nut shells to fuel their boiler they are unhappy with the amount of air pollution caused by the unburned CNSL. We also stopped at two agricultural research stations, in Bole and Wenchi, where we saw many varieties of cashew apples, heard about research on grafting and other agroforestry improvements, simple wine and alcohol production trials, and experiments to use dried cashew apple pomace for animal feed. Unfortunately, we didn’t have time to visit the Benedictine monastery in Techiman, where they are said to sell processed cashew apple products. Nowhere in Ghana did we get to observe fresh cashew apples (or any cashew apple product) for sale, but it could be that we were travelling too quickly; we did take every opportunity to sample the fruit and indeed found them too fragile to transport far, extremely juicy and sweet, and causing a bite of astringency at the back of the throat.

We were met at the Burkina Faso by our able escort/driver Sekou, and now that we were in French speaking territory our translator Maria Mathess proved especially invaluable. We appreciate all the help from the Ouagadougou PDA/GTZ office (the Agricultural Development Programme) – particularly Philippe Constant and Andrea Wilhelmi-Some – as we galloped from one meeting or production facility to another in Banfora and Bobo. From the second we entered BF we occasionally encountered children selling cashew apples from baskets on their heads, so we were able to use our “community engagement” tools to inquire how people value the fruit – all of the ones we tried were fibrous and the only way of consuming them seemed to be to suck out the juice and spit out the rest. As we visited several cashew production facilities (such as Sotria-B) we received the same request – help is needed particularly in extracting value from the oily shells (~25% CNSL by weight), since there is presently no way to burn them cleanly; each operation has a similar field of accumulating shells, and everyone would benefit from their efficient use. All over this portion of Africa fuel (such as wood and charcoal) is in short supply and so it is criminal that trees must be cut down when shells are so energy rich and plentiful. Later we found that a government research institution in Bobo (IRSAT, with GTZ/FAFASO) has an active program to extract the CNSL and use the remaining dry nut shells for fuel for improved cooking stoves – in cashew growing regions all over the world there is a need for simple extraction methods (and adequate markets for the CNSL), as well as ways to cleanly combust un-extracted shells for those instances where CNSL extraction is not feasible.

We also visited several cooperatives (like Association Wouol and Coopake) where cashews and dried mangoes are processed, and sampled some of the very first dried cashew apples in this region – these organizations desire new products to benefit their members so proved very receptive to learning about cashew apple products that have proven popular in other parts of the world (particularly Brazil). With Rakesh Gupta (TechnoServe) we met with representatives of DAFANI, a juice manufacturer eager to add new juice mixtures to their line, and perhaps install a biogas fermenter to capture value from their waste pulp. We spent considerable time at L’Union Yanta, both at their plant and in their cashew orchards, learning about the community that supports them. We visited a nearby home where a meeting had been organized for us to talk with families – always an important part of EWB assessment trips – and regaled several generations with our stories of cashew apple uses around the world. As always we asked “What can we do for you?”, and typically found that expanding the uses of cashew apples is probably a marketing rather than a technology problem – all the right information conceivably already exists, now how do we get it to the people who want it? Recipes, solar fruit driers, simple juicers, cooking demonstrations, technical information transfers, and so on might all be part of a comprehensive effort to encourage greater utilization of this valuable resource. And, as in most areas of the world where cooking is done with biomass, fuel is one of the largest daily expenses so access to the energy in the nearby nut shell middens would be appreciated – the best forms might be briquettes or charcoal, both areas of active interest to those developing improved stoves all over the world. For larger scale applications - say to produce process heat for industry or to provide rural electrification - gasification of shells in a reactor is the cleanest and most efficient method.

In conclusion, as we travelled we found encouraging signs everywhere – uses for cashew byproducts are of interest to everyone (and the internet is full of activities in other countries as well – waste is in no one’s best interest, so attracts attention) – and we saw or heard of examples of most of the possible uses we imagined ahead of time. The fact that commercialization of many of these has not already occurred suggests that there are hard problems to be overcome, particularly if we are to make good use of the shells. But then the expertise of ATDT members wouldn’t be needed if everything was already figured out…

Its a shame not to have more space for trip photos - you can find additional ones here!

Short video of my experiment comparing the pyrolysis (on a bed of hot charcoal, with forced air) of U.S. English walnut shells, and Burkina Faso CNSL saturated cashew nut shells. In both cases the pyrolysis gases burn nicely, and the CNSL does not seem to interfere - when they are added gradually to existing combustion. Inside a gasifier fully loaded with cashew shells we hope that the CNSL will not drain too quickly into the combustion zone as the shells preheat, resulting in noxious smoking.:


YouTube has many many videos of cashew processing throughout the world, including Thailand, Guinea-Bissau, Sri Lanka, Benin, India, Vietnam, Indonesia, Brazil, Philippines, and more. They show different levels of automation, and many discuss cashew apple utilization as well!

1 Comments:

Anonymous Anonymous said...

Ole Charlie has done it again.
Good work and excellent writing
fella. op

8:01 PM  

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