Example Measurements of the Moisture Content of Biomass Charlie Selllers, March 27, 2009 Perfectly dry biomass would be a boon for stove testing (and for use by cooks around the world) but it is rarely available – therefore we should at least know what our moisture content is so that we can estimate how much of our energy we are using up boiling it, instead of having it available to work with. After seeing Tom Miles’ post on the standard procedure for microwave drying of wood (I thought that I developed this in my kitchen a few years ago!): http://gasifiers.bioenergylists.org/milesmccontent Here I dig up some of my own data – I need to know moisture content for preliminary cooking stove Water Boiling Tests (WBT), and it is also one of the major variables when operating biomass gasifiers. Understanding water re-uptake by biomass is important as well – whether it is due to changes in the weather, it occurs after we open a new bag of wood pellets to be used for baseline testing, we needed to move our supply from one place to another, or because we have gone to all the trouble of using producer gas to dry fuel but don’t have time to burn/gasify it for a few days. See report attached.

Paul Anderson, March, 2009

I. Proposal:
“Air-controlled” biomass cookstoves should be seriously examined as viable replacements for charcoal cookstoves in urban and peri-urban communities in developing societies.

II. Situation, Problem and Opportunity:
Throughout the urban areas of developing societies, charcoal cookstoves have an important role in
residential cooking (including other small-scale cooking in restaurants and institutions). The acceptable energy sources for urban cooking are charcoal, LPG, kerosene, alcohol, and electricity. (Solar cooking is omitted because of housing densities and shadows.) All of them require significant “conversion” from their natural sources, and are deemed to be sufficiently clean energy, meaning a “lack of bothersome smoke” or very low emissions of particulate matter (PM).
Charcoal competes well against those other high-order heat sources because it is easily and relatively inexpensively made from wood and other dry biomass by unskilled labor. But charcoal has two major drawbacks: A) very high levels of carbon monoxide (CO) emission; and B) the destruction of local vegetation from which the charcoal is made. Therefore, it is important to examine viable alternatives such as modern cookstoves that efficiently combust raw dry biomass such as wood which yields CO and PM emissions (“smoke”) even lower than those of charcoal stoves. If these new stoves are successful, task-appropriate, and sustainable for urban cooking, they will also significantly reduce the problems of deforestation and greenhouse gases while providing urban residents with economical and convenient fuel alternatives.