Evaluation of a Water Scrubbing Process for Biogas Enrichment

There has been an increasing interest in biogas production, storage and utilization, due to global warming concerns and the need for renewable energy. Raw biogas contains impurities (CO2 and H2S) which limits the energ y content and lowers the heating value. The use of upgrading processes to remove incombustible gases from raw biogas increases its methane content and energy capacity. Water Scrubbing, based on the physical effect of dissolving gases in liquid is a method of upgrading biogas. This study modeled and evaluated the enrichment parameters needed to achieve a minimum biogas purity of 95% using a step wise variation technique on CHEMCAD  modeling and simulation tools. Chemical Process simulation software tool, CHEM CAD, was applied for the simulation. The optimal  operating parameters for methane enrichment of 97.43% was obtained at 2.5atm inlet gas pressure, 1.2m 3 /hr gas flow rate and water flow rate of 12m 3 /hr. The findings indicate that water scrubbing may be a rea dy procedure for biogas enrichment

Design, fabrication and performance evaluation of a powered soy-gari mixer

Aprototype mixer consisting of a trough, rotating shaft and blade mounted on a shaft and driven by a 2 horse power electric motor was designed, fabricated and its performance evaluated at 50% of its capacity by volume for mixing of different particle sizes of gari namely small (1.18 mm), medium (1.70mm)large (2.30mm)and locally sieved, mixed with soybean flour and paste respectively. Results show that power requirement for mixing of soy-gari increased with the particle size and was higher in the mixture of gari and soy-paste (SGP) than gari and soy-flour (SGF). Smallparticle sizes were found to mix faster than large ones for both SGFandSGP. It was observed that low speeds of rotation and low power requirement of the machine increased the mixing efficiency and throughput capacity. Water absorption capacity and least gelation concentration of all the samples decreased slightly with increasing particle sizes. On the other hand, bulk density and swelling index of all the samples consistently increased as the particle sizes became smaller. The results of Sensory analysis indicated that mixture of medium particle size of gari (1.70mm) with soy flour was rated as having the best quality and was therefore, recommended.Key words: Design, Fabrication, Performance, Soy-gari, Mixin

Nutritional assessment of instant poundo yam from yellow yam (Dioscorea cayenensis) supplemented with yellow cassava (manihot esculenta) flour

The major objective of this study was to investigate the nutritional properties of yellow yam flour supplemented with yellow cassava flour. Specifically, the study dertermined functional properties of the yellow yam and yellow cassava flour blends, pasting properties of the yellow yam and yellow cassava flour blends, effect of supplementation on the sensory properties of the instant pound yam paste produced from yellow yam flour supplemented with yellow cassava flour. Good quality yellow yam (Dioscorea cayenensis), tubers and yellow cassava (Manihot esculenta) and UMUCASS38 roots were obtained from International Institute for Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria. Samples were prepared by appropriate methods. The flour blends were formulated and instant pounded yam flour prepared. Functional analysis and sensony evaluation were carried out. Results of the analysis show the following ranges; oil absorption capacity 70.25-85.63%; water absorption capacity 73.89-78.69%; bulk density 0.76-1.59g/m3; peak viscosity 158.36-210.43 RVU; final viscosity 178.53-277.15RVU; setback viscosity of cooked paste 51.53-72.54 RVU; pasting time 5.95-8.65 min; breakdown viscosity of the cooked paste 8.75-9.53RVU; pasting temperature 62.55-67.130C; trough 152.46-180.16 RVU. The general acceptability of all the supplemented samples were highly rated (8.00 each) as compared to control sample which had the lowest (6.05) value. Commercial production of instant poundo yam from yellow yam and yellow cassava flours will serve as a strategy of alleviating the challenge of food insecurity in Nigeria