Alkebulan uses sugarcane bagasse to create its non-carbonized briquettes. There are 12 sugar mills in Kenya which produce 2.4 million tons of bagasse each year that still remains unused. Additionally, the energy potential for the unutilized bagasse is predicted to reach 300 MW (Global Bioenergy Partnership, 2019). Sugarcane bagasse is the part of the sugarcane which is primarily composed of cellulose. It is a sugar industry waste material that can be subjected to different chemical and mechanical treatments in order to extract cellulose nanocrystals, cellulose nanofibers, pure cellulose and cellulosic fibers which can then be used in various applications such as biofuel, feedstock, and for the paper industry, to name a few (Mahmud & Anannya, 2021).
Sugarcane bagasse grows differently in Kenya than in other places for several reasons, including: difference in temperature and climate at the equator and the lack of nutrients in the soil. Kenya has low soil fertility due to crop harvests with no soil replenishment, or very little, and erosion. In the highly populated Western province, the soil productivity is low and continuing to decline. Nitrogen, Phosphorous, and Potassium are widespread in the western province. Nitrogen is an essential nutrient involved in physiological processes. It’s essential for sugar production and is the main building block of protein, and, it is worth noting, a briquette with low calorie content will not burn as long or as efficiently. High levels of potassium can reduce sucrose levels and the amount of fiber in the plant (the feedstock), so the lower potassium in Kenya’s soil could be a blessing – more sucrose equals more calories and more fiber is more material for briquetting (Okello, 2012).
In East Africa, there is not currently an abundance of technical knowledge regarding the briquettes-from-bio-waste industry. Many are unaware that since the bagasse is different in Kenya than elsewhere, it requires different machines to process than the industry standard uses – this is knowledge that must be disseminated in order to ensure efficient processing of agricultural waste; efficiency leads to a cost-effective product, for both the producer and consumer. There are sugarcane diseases and pests that are specific to Kenya. There are 30 diseases caused by phytoplasma, viruses, bacteria, and fungi that are present in Kenyan sugarcane. Some of the more influential are: Sugarcane Smut, Ratoon Stunting Disease, Red Rot, Sugarcane Mosaic Virus, Sugarcane Rust, and Pineapple Disease. A majority of the diseases are systemic and planting infected seeds can lead to infected plants (Sugarcane Research Institute, N.D.) The pesticides used to protect the crop can modify the plants in various ways. Certain pesticides can lead to genotoxicity (damage to genetic material that causes mutations) and binding of these chemicals with DNA is highly likely. A majority of pesticides are electrophilic (tend to attract/acquire electrons) and can be reactive at multiple locations in the plant DNA. This can change the makeup of the nucleic acid and impede proper replication leading to altered plant structure (Boerth, 2003).
Plant DNA can be impacted by ultraviolet radiation, both UV-B and UV-C, leading to mutations in DNA replication. The epidermis of the plant is the first to intercept radiation, so it can impact the amount of radiation the rest of the plant receives and is, therefore, a protective barrier from the harsh rays (Hollósy, 2002). The intensity of the sun at the equator has toughened the skin of the crop and made the fiber longer and thicker (200 mm x 1 mm versus 50 mm and thin as a strand of hair) – nature’s way of blocking the rest of the plant from the harmful effects of the sun. The fiber is also stickier because of leftover sugar after extraction. This applies to other plants in Kenya as well: Casava, Maize, Banana, Coconut, Cotton, Tea, Coffee, rice, etc. are all thicker, tougher, and stickier – all of which can be used to make non-carbonized briquettes (Punit Nigam, N.D.).
The agricultural waste must be dried down to less than 15% moisture content in order to be briquetted. This can be done using Industrial rotary systems or the open air, then they are cleaned and shredded (and sometimes dried again), then high pressure is applied to create the final product (Punit Nigam, N.D.). As mentioned earlier, there are many different feedstock materials that may be used to make briquettes, however, the combination of materials must contain nearly zero impurities like sand, ash, fertilizers, lignin, etc. Also, they must be combined in specific proportions to achieve the best results. Flue gases will be impacted by the properties of the fuel, so the quality of the raw materials in the briquette will not only impact the caliber of the food, but, above all, how the emissions impact the environment and human safety. CO2, CO, and particulate matter are correlated with the number of contaminants in the briquettes. This correlation is the strongest within the first 20 minutes of ignition. Therefore, burning briquettes with a high amount of impurities is particularly unsafe for consumers at the primary stages of cooking and is best to be avoided altogether by eliminating these substances from the feedstock (Jelonek et. al., 2020).
A quality briquette has a high calorific value, a high density and is resistant to humidity. The higher the calorific content, the more efficiently the briquette will burn. The higher the density of the briquette, the more heat it produces and the longer it will burn. Raw material with smaller particles will lead to a higher density briquette, and the higher the raw material water content, the lower the density which means you must process the raw materials beforehand. Briquette quality will also be impacted by physical parameters in the briquetting procedure such as moisture content, compacting pressure and pressing temperatures (Huang, 2019). A battery of machines is required to process the feedstock, and there is a better result if the entire process is automated; although, it must still be checked at various stages.
Briquettes from agricultural waste is still a burgeoning market in Kenya with little knowledge on the necessity of unique machinery to handle the tougher plant varieties that occur due to the unique climate and specific pesticides used on the crops. The briquetting process is very specific and requires the raw materials be dried, sometimes more than once, and broken down into small pieces and very little is known about the nuances of using Kenyan feedstock vs feedstock from other countries.
Boerth, D. W. (2003, August 1). Pesticide Impact on Plant DNA. Pesticide Impact on Plant DNA – University of Mass Dartmouth. Retrieved December 15, 2022, from: https://reeis.usda.gov/web/crisprojectpages/0196383-pesticide-impact-on-plant-dna.html
Common Sugarcane Diseases and Pests in Kenya. (n.d.). Sugarcane Research Institute. Retrieved December 12, 2022, from: https://www.kalro.org/sugar/sites/default/files/Sugar-PESTS-booklet-formatted-15-04-13.pdf
Huang, J. (2019, September 9). Factors That Influence Your Briquettes Burning. Renewable Energy World. Retrieved December 6, 2022, from: https://www.renewableenergyworld.com/baseload/factors-that-influence-your-briquettes-burning/#gref
Hollósy, F. (2002). Effects of Ultraviolet Radiation on Plant Cells. Micron, 33(2), 179–197. https://doi.org/10.1016/s0968-4328(01)00011-7
Jelonek, Z., Drobniak, A., Mastalerz, M., & Jelonek, I. (2020). Environmental Implications of the Quality of Charcoal Briquettes and Lump Charcoal Used for Grilling. Science of The Total Environment, 747. https://doi.org/10.1016/j.scitotenv.2020.141267
Mahmud, M. A., & Anannya, F. R. (2021). Sugarcane Bagasse – A Source of Cellulosic Fiber for Diverse Applications. Heliyon, 7(8). https://doi.org/10.1016/j.heliyon.2021.e07771
Okello, N. J. (2012). Evaluation of Fertilizer Formulations on Soil Chemical Properties, Growth, Yield and Quality of Sugarcane Variety in Kakamega County, Kenya. School of Agriculture and Enterprise Development of Kenyatta University.
UN Environment. (2019). Building Capacity for Enhancing Bioenergy Sustainability Through the Use of the Global Bioenergy Partnership Indicators. Global Bioenergy. Retrieved October 24, 2022, from: http://www.globalbioenergy.org/fileadmin/user_upload/gbep/docs/AG2/Ethiopia_and_Kenya/GBEP_brochure_final.pdf