Abstract—This study is focused on the development of biodigester, and the mathematical modeling of biogas production with 50% and 80% by volume of monosubstrate of Hay, Corn and Cow Manure. The mathematical model was developed using the designed and fabricated 2750 cm 3 digester within 31 days which was proven to be significantly related to the density of gas and temperature. The 50% by volume Hay, Corn and Cow Manure revealed a significant correlation coefficient of determination (R 2 ) values of 0.5294, 0.1271 and 0.0702 respectively and 0.3685, 0.1187 and 0.2841 for 80% by volume monosubstrate samples with respect to the density of gas. However, it was found out that the density of gas significantly increases as the %CH 4 yield decreases or vice versa (except for 50% by volume monosubstrate Cow manure sample) for Hay and Cow Manure monosubstrate samples and the density of gas of Corn sample increases together with its increasing %CH 4 yield. The significant relationship among the samples towards temperature and time is said to be proportional to each other for both Hay and Cow Manure and opposite to the Corn sample. Furthermore, it was established that the significant effect of density of gas and temperature with time considering 50% by volume of Hay and Corn monosubstrate samples and 80% by volume of Hay, Corn and Cow manure monosubstrate samples lead to the development of the modeled equation following the 2 nd order reaction. Index Terms—Biodigester development, kinetic study, biogas and biomass. II. OBJECTIVES AND SIGNIFICANCE OF THE STUDY The study focused on the development of a biodigester with kinetic modeling of biogas production from biomass. Specifically, it aimed to achieve the following sub-objectives: (1) Characterize the following feed materials, in terms of pH, total solids, (TS), and volatile solids (VS) (a) Hay, (b) Corn, and (c) Cow Manure substrate; (2) Establish the properties of Hay and Corn substrate in terms of (a) Crude Protein (XP), (b) Crude Fat (XL), and (c) Crude Fiber (XF); (3) Determine the biogas yield of the monosubstrate of Hay, Corn and Cow manure in terms of the following: (a) density of the influent, (b) density of the biogas, (c) temperature, (d) concentration of carbon dioxide, (e) maximum biogas yield, and (f) the no. of days required of producing maximum biogas yield; and (g) Develop the kinetic model equation for the production of biogas in a batch reactor. III. METHODS AND DESIGN This research design utilized experimental method in determining the desired analytical evaluation to develop a kinetic modeled equation that was used in designing a biogas reactor of the same influent. A. Biogas Digester and Its Fabrication The reactor that was used in this study was fabricated and assembled guided by the design layout of the biodigester (Fig. 1) at the Workshop Area of the Mechanical Section of Engineering Department of Ibra College of Technology, Ibra, Sultanate of Oman. Biodigester Development and Kinetic Study of Biogas Production from Biomass Sherwin T. Sepe, Melito A. Baccay, Baba E. Jibril, and Yahya M. Al Wahaibi 138 International Journal of Chemical Engineering and Applications, Vol. 5, No. 2, April 2014 DOI: 10.7763/IJCEA.2014.V5.367 I. INTRODUCTION Environmental degradation and increasing prices of conventional energy resources are driving the global shift towards the renewable [1]. The advantages of using biogas reactor system are under greenhouse gas initiative, minimize unpleasant odor, prevent disease transmission, and generate heat, power and by product such as solid and liquid fertilizers [2]. Biogas technology has been introduced in 1980, thus it is not a new innovation around the world [3]. However, its success was sluggish due to various contains such as lack of technical expertise, misfunction of biogas reactor enough to establish liability due to the proportion of the yield and reactor size, non–user friendly design, manually handling or organic load, and in enticing or expelling sludge from reactor. Therefore, in-depth study of reaction kinetics that will connect the discrepancy of the actual fabrication between the reactor and the production yield of the biogas is highly regarded [4]. It was agreed by Widodo and Nurhasanah [5] because by introducing the new approaches for its development were explicitly required. And the researcher come up the idea of investigating the factors affecting the rate of biogas yield of energy crops and animal wastes slurry and develop a mathematical model of the rate of kinetics based on the determined order of reaction to optimize industrial production of the gas. Manuscript received August 8, 2013; revised November 23, 2013. This work was supported by the Department of Petroleum and Chemical Engineering of the College of Engineering, Sultan Qaboos University, Department of Engineering of Ibra College of Technology, Ibra, Oman and the Philippine Women’s University, Manila, Philippines. The study is entitled Biogas Development and Kinetic Study of Biogas Production from Biomass. Sherwin T. Sepe was with the Department of Sciences under Chemistry Section of Higher College of Technology, Muscat. He is now with German University of Technology, Muscat Sultanate of Oman (tel.: +968-97722485; e-mail: sherwin.sepe@gutech.edu.om, s_sepe_6300@yahoo.com). Melito A. Baccay is with the College of Engineering of Technological University of the Philippines, Manila, Philippines (e-mail: melbaccay@yahoo.com). Baba E. Jibril is with the Petroleum and Chemical Engineering Department of Engineering, Sultan Qaboos University (e-mail: baba@squ.edu.om). Yahya M. Al Wahaibi is with the Department Head of Petroleum and Chemical Engineering of the College of Engineering, Sultan Qaboos University, Sultanate of Oman (e-mail: engpce@squ.edu.om).