Waste to renewable energy: biogas cleanup (upgrading) in Tanzania and Kenya
PI: Cecil Kithongo King’ondu (kithongo.king’firstname.lastname@example.org
), with co-PIs Askwar Hilonga and Revocatus Machunda, Nelson Mandela African Institution of Science and Technology, and Owino Joseph Hazael Odero (email@example.com
), South Eastern Kenya University
U.S. Partners: Puxian Gao and Steven Suib, University of Connecticut
Project dates: December 2014 - May 2017
The adoption of small and large-scale biogas production technology is on the increase in Africa, first, due to the need to supplement conventional power, which is inadequate and unreliable in the urban centers and missing in rural areas, and second, due to the growing environmental concerns associated with the use of fossil fuels. However, despite the growing biogas generation and utilization, there is no technology available for biogas cleanup. In Kenya and Tanzania, biogas is utilized as-produced, with no attempts to clean it, mostly by households, schools, flower farms, and other establishments. This is because the citizenry are either oblivious of the contaminants present in biogas and their detrimental effects on human health, the environment, and the infrastructure or there is no affordable technology available for biogas cleanup. This project is intended to create awareness among the general public of the contaminants in biogas and their effects on human health, the environment, and infrastructure; build capacity of academic staff and graduate students in biogas cleanup; and develop inexpensive, effective, and reliable technology for domestic and large-scale biogas cleanup. Biogas contains a plethora of toxic compounds such as siloxanes, hydrogen sulfide, carbonyl sulfide, carbon disulfide, dimethyl sulfides, and halogenated compounds. Hydrogen sulfide is the major contaminant in biogas and is highly toxic when inhaled. When uncleaned biogas is burnt for cooking or electricity, the sulfur compounds are converted to SOx gases, which corrode epithelial linings of human respiratory system. Additionally, SOx gases are associated with acid rain that wreaks havoc on our infrastructure. This project involves fundamental studies of biogas cleanup and development of a cheap and effective technique for biogas desulfurization at room temperature. The Nelson Mandela African Institution of Science and Technology (NM-AIST) and South Eastern University of Kenya (SEKU) will work on a tandem oxidative-adsorptive desulfurization process to remove both the H2
S and more refractory organic sulfur compounds from biogas at room temperature. A cheap and effective biogas cleanup technique will significantly reduce emission of H2
S and SOx gases to the environment and most importantly reduce the exposure of people, especially women, to the toxic H2
S and SOx gases.
This work will help provide additional impetus for unraveling the great potential Tanzania and Kenya have in turning waste into renewable energy. It will also educate the general public, academic staff, and graduate students on risks posed by the use of biogas laden with sulfur and other noxious compounds. Undergraduate and graduate students at South Eastern Kenya University and graduate students at NM-AIST will be involved in this research and will actively participate in joint meetings. Chemical engineering/chemistry mini-courses in nano-science, catalysis, and adsorption will be developed for undergraduate and graduate students. Special attention will also be paid to outreach programs where the project will target diverse and underrepresented (in scientific research) groups such as primary and secondary students as well as the locals in the two cities: Arusha in Tanzania and Kitui in Kenya. The project will also endeavor to encourage the establishment of a special lab for students with disabilities. Most importantly, the development of a cheap and effective tandem oxidative-adsorptive desulfurization process will lay the foundation for deep desulfurization of biogas for fuel cells. Fuel cells have very low sulfur tolerance but their efficiency is unmatched by all other energy sources. A deep biogas cleanup technique will not only open doors for the adoption of fuel cells technology in Tanzania and Kenya but also reduce, significantly, the amount of natural gas used for fuel cells in developed countries like the United States, thereby reducing greenhouse gas emissions. The biogas cleanup technology developed will be transferred to households, schools, flower farms and stakeholders in the clean energy field. The U.S. collaborator will play an instrumental role during the scale-up stage of the process and technology transfer.Summary of Recent Activities
During this reporting period ending December 2016, synthesis of manganese oxide and water hyancith derived carbon nanomaterials that showed good performance during screening tests was scaled -up and enough materials for first generation prototype filters successfully prepared. This has addressed objective number 2,3 and 4 in the original proposal. In addition, first generation of the prototype filters were fabricated and their performance in removing hydrogen sulfide tested at Banana Investment Limited. Performance testing of these filters has now been accomplished. The results obtained from these studies are promising since the filters took more than a month to get saturated. Second generation of the prototype filters having both the adsorptive and catalytic units in tandem are currently being tested, first with the catalytic unit facing the gas inlet. After this the same filters will be tested with the adsorptive unit facing the gas inlet and the performance compared. This is addressing objective number 4 in the original proposal.
In February 2017, a workshop on biogas cleanup: opportunities/challenges in Tanzania and Kenya will be conducted. Invitations have been sent to students, NM-AIST staff, and representatives from Tanzania Renewable Energy Agency (TAREA), non-government, and private entities involved in promotion of biogas technology, biogas consumption, regulation of renewable energy. Specifically, representative from Q-SEM (an horticulture farm near NM-AIST and a large scale biogas producer and consumer), Banana Investment (private winery company that produces biogas and consumes at large scale), Tanzania domestic biogas program (government institution), Gongali Model Co. Limited (an NGO involved in promotion of biogas use among other things), SNV (a Tanzanian based, Dutch funded NGO involved in promotion of biogas and bioslurry production and utilization. During this workshop, we intend to showcase out filters and probably donate one to Banana Investment Limited (BIL). Further to showcasing, the workshop will provide an opportunity to discuss emerging challenges and opportunities in biogas technology.
Similar but a concluding workshop will be held at SEKU late April 2017. As from January 2017, we will explore the possibilities of initiating invention disclosure with Brela (Business Registrations and Licensing Agency) in Tanzania.
In the next few final months, second generation of the prototype filters having both the adsorptive and catalytic units in tandem will continue being tested, first with the catalytic unit facing the gas inlet. After this the same filters will be tested with the adsorptive unit facing the gas inlet and the performance compared. This is addressing objective number 4 in the original proposal.PEER Cycle 3 Grant Recipients