Final Report: Peanut Shell Fuel for the GambiaEPA Grant Number: SU834702
Title: Peanut Shell Fuel for the Gambia
Investigators: Zhang, Hong , Everett, Jess , Falvo, Nicholas Thomas , Lavertu, Daniel Raymond , Mease, Bradley Richard , Mirto, Nicholas , Trapper III, Edward Arthur , Tryner, Jessica
Institution: Rowan University
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: August 15, 2010 through August 14, 2011
Project Amount: $9,300
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2010) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Agriculture , P3 Challenge Area - Energy , P3 Awards , Sustainability
The objective of the project is to develop a system for producing quality peanut shell briquettes for use as an alternative to wood cooking fuel in rural Gambia. The ways that different factors in the material preparation and briquette forming process affect peanut shell briquette quality were investigated. From this work, the basic material preparation process required to make functional peanut shell briquettes was determined. Presses for compressing the raw material into briquettes were tested using specific consideration of the limited resources in rural Gambian villages.
Design changes were often necessary to ensure the sustainability of the project by ensuring that the press could be constructed only out of materials that are readily available to those living in rural Gambia.
- All three of the briquette presses tested (Legacy Foundation press, modified Legacy Foundation press, and steel frame scissor jack press) satisfactorily compressed briquettes.
- Square briquettes were just as easy to produce, were just as durable, and burnt just as well as round briquettes.
- It was possible to further modify the press designs to fit the field conditions while still retaining the ability to produce quality briquettes.
The process used to prepare the briquetting material has far more influence on briquette quality than the mechanics of the briquette press. It was determined that whole peanut shells could be compressed into durable briquettes by preparing them in one of three ways:
- Crushing the shells by hand and adding a binder
- Crushing the shells by hand and then anaerobically composting them for several weeks.
- Grinding the shells into small particles (without composting)
Methods 2 and 3 require no binder except water. This was desirable since most binders are food products and therefore use of a binder would require materials to be diverted from a household’s food supply to produce briquettes.
The crushed and composted briquettes had a density that was about 1/3 of that of the ground briquettes. The crushed and composted briquettes were also significantly less durable. The disadvantage of the crushed and composted briquettes was that they burnt fairly quickly: 4 briquettes could be prepared from already crushed and composted material in about 15 minutes, but would burn in only 10 minutes. The denser briquettes made from ground shells were so dense that they were difficult to burn. When lit they would simply smolder and not maintain a consistent flame, even when they were placed on top of a briquette fire that was already burning.
The calorific value of the compressed peanut shell briquettes was higher than the calorific value of wood by weight. Firewood typically has a calorific value around 8,000 Btu/lb, but the peanut shell crushed and composted briquettes were found to have an average calorific value around 12,000 Btu/lb.
The steel frame scissor jack press design is believed to be the best design for construction in rural Gambia due to the ubiquitous availability of motor vehicles and the ease of construction from existing scissor jacks used in these vehicles. Using this press and method 2 described above it is possible to produce fuel briquettes from peanut shells that will burn on an open cooking fire.
True success of the project can only be determined after engaging in field testing in rural Gambian villages. Field testing is required to determine:
- Whether the briquetting process requires too much effort in the eyes of the users
- Whether the briquette press really is easy and affordable to construct using local skills and materials
- Whether the briquettes burn satisfactorily as an attractive cooking fuel by the local people.
It would also be useful to identify a material preparation process that could be used to produce briquettes with a density somewhere in between that of the crushed and composted briquettes and that of the ground briquettes. The goal of this process would be to produce briquettes that light easily, sustain a flame, and do not produce a lot of smoke, but burn slowly. Overall, the material preparation process used with any briquetting material must undergo optimization to produce quality fuel briquettes.