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- ItemCombustion characteristics of Torrefied corncob and African birch wood residues at higher heating rate(2025) H.A. Ajimotokan; N.S. Saidu; M.A. Aladodo; K.O. Oladosu; O.D. Samuel; K.O. Abdulrahman; A. El-Suleiman; Y.S. Salihu; K.R. AjaoThe torrefaction of biomass generated from by-products of post-harvest agricultural activities such as corncob or woody residues from saw milling, pruning, and furniture production such as African birch wood, are renewable energy sources whose pyrolytic and combustion properties are crucial during process heating in various applications. This study investigated the combustion characteristics of corncob and African birch wood residues at a higher heating rate and their comparative energy qualities. Samples of corncob and African birch wood residues were collected, sorted, pulverised into particles, and torrefied independently. The raw and torrefied corncob and African birch wood particles were screened into 0.3, 0.5, and 1.0 mm sizes, and their thermogravimetric, proximate, ultimate, heating values, and energy quality analyses were carried out. The torrefied biomass showed better pyrolytic and combustion characteristics relative to the raw samples. However, African birch wood residues appear to be better than corncob residues. The higher heating values (HHVs) ranged from 21.46 to 21.63 MJ/kg and 23.1 to 25.6 MJ/kg for the torrefied samples of corncob and African birch wood residues, respectively. The torrefied sample of African birch wood residues exhibited the highest HHV (25.6 MJ/kg), which compared favourably with the value from a low-rank coal, such as lignite or brown coal. Torrefied African birch wood residues, with their high HHV, can be densified to replace low-rank coal and firewood in a variety of applications.
- ItemTHE EFFECTS OF PARTICLE SIZE, COMPACTION PRESSURE, AND TORREFACTION ON QUALITY AND THERMAL PROPERTIES OF PELLETIZED CORNCOB RESIDUES(2022) SAIDU, Nurudeen Sabi; ALADODO, Muhammad Alamin; AJIMOTOKAN, Habeeb AdewaleTorrefaction and biomass pelletization into pellets for solid fuel development are considered sustainable energy solutions to mitigate fossil fuel dependency and environmental challenges. This study investigated the effect of particle size, compaction pressure, and torrefaction on the quality and thermal properties of pelletized corncob residues. The corncob samples were collected, sorted, and pulverized before the torrefaction pretreatment. The torrefaction was achieved by placing the corncob in a furnace at a temperature and residence time of 280 °C and 30 minutes, respectively. The inert atmosphere was attained and maintained by initially purging a nitrogen gas into the torrefying chamber and passing it at 100mL/min during the processes. The raw and torrefied corncob fines were screened to 0.3 mm, 0.5 mm, and 1.0 mm grain sizes. Using starch as a binder (5% wt), pellets were produced employing their respective raw and torrefied fines at compaction pressures of 50 MPa, 75 MPa, and 100 MPa. Though all pellet samples exhibited good quality and thermal properties, the pellets from torrefied corncob are better. Also, the effects of particle size and compaction pressure are significant on the produced pellets. The compressed density varied from 760 to 1,250 kg/m3 and 637 to 920 kg/m3 for raw and torrefied corncob pellets. A maximum heating value of 25.8 MJ/kg was obtained from the torrefied pellet sample of 1.0 mm, rendering improvements of 37.2% when compared with 18.8 MJ/kg of raw corncob of the same particle size. The energy values obtained for torrefied corncob for all particle sizes compared favorably with the value obtained in coal. Investigation of particle size, compaction pressure, and torrefaction on quality and thermal properties of pelletized corncob residue proved that it can replace coal and hence could be used for energy applications.
- ItemDesign and development of vapor absorption refrigeration system for rural dwellers(Covenant University, 2012) Adekeye, T; Oyedepo, S.O; Oyebanji, J.A
- ItemEvaluation of thermal comfort in a test room equipped with a photovoltaic assisted thermoelectric air duct cooling system(Elsevier, 2017-08-26) Kashif Irshad; Khairul Habib; Kareem, M.W.; Firdaus Basrawi; Bidyut Baran SahaThis study investigates the comfort performance of a test room equipped with the southfacing photovoltaic wall (PV-W) and north-facing thermo-electric air duct (TE-AD) system for the tropical climate. Both subjective and objective measurements were used to analyze the TE-AD system cooling performance when operated at variable input current supply (2e7 A) from a PV system. Indoor radiant and air temperatures, relative humidity, and air velocity were measured based on ISO 7730 for objective measurement. For subjective measurement, forty respondents were required to fill up the questionnaire that developed based on UNI EN ISO 10551 and UNI EN ISO 7730 guidelines in order to access their thermal comfort opinion. The results show that the thermal response of respondents associated with indoor situation of the test room have changed from (þ1) slightly warm to cool ( 2) when the input current supply rises from 2 A to 6 A. The overall predicted mean vote, predicted percentage dissatisfied indices, and acceptability vote shows that more than 90% of the respondents were thermally satisfied. Integration of the PV-W system with the TE-AD system increases the thermal comfort and reduces the thermal load of the test room with other benefits includes less fuel and energy consumption, high reliability, and less maintenance operation.
- ItemA Review on MHD Mixed Convection with Nanofluids in Regular and Irregular Geometries(Journal of Thermal Energy Systems, 2023) Adekeye T; Okekunle P. O; Adegun I. K