Optimization for Biogas Power Plants using Automatic Control of Gas Pressures
In many cases, gas storages on biogas power plants are not used optimally to store gas as much as their capacity. The digester is sometimes overload to store gas and the controller cannot deliver gas to other storage. Consequently, gas is often released from digester to avoid over pressure. At the end, biogas power plant has less efficiency. Hence, a mechanism to control gas pressure to make different pressure between its storages is required. Fans were used to manipulate the most majority system pressures on a biogas power plant using frequency converters. Measurements, simulations, and experiments were conducted to create a new system on a biogas power plant. A controller, Programmable Logic Controller was used to control the entire system pressure using Proportional-Integral-Derivative algorithm. When the gas pressures are not in the allowable range of pressure, then the controller changes the fans’ frequency to the desired conditions. As a result, gas moves to another storage and system pressures are in the allowable range.
Study of Biogas for Power Generation at Pesantren Saung Balong Al-Barokah, Majalengka, West Java
Utilization of biogas from cow manure as a fuel alternative for power plants is done through an anaerobic process. A pilot plant with biogas production of 7 m 3 /day has been installed at Pesantren Saung Balong. Biogas is used for everyday purposes such as cooking and lighting, and used as pure biogas with 2.500 Watt scale generator. Biogas produced with the rate of 0.080 m 3 /hr. Biogas produced during the measurement (450 minutes) is 0.604 m 3 . With these data it is predicted that within a day (24 hours) biogas which can be generated is equal to 1.92 m 3 . Meanwhile, consumption of biogas to the generator with 1.047 W load is 0.019 m3/minutes, the generator will operate for approximately 101.05 minutes or 1.68 hours. Thus electricity that can be saved is 1.759 kWh per day or 52.77 kWh per month and electricity cost that can be saved that is equal to Rp.40.896/month.
Copper Phthalocyanine Improving Nonaqueous Catalysis of Pseudomonas cepacia Lipase for Ester Synthesis
The nonaqueous catalysis of lipases is significant for synthesis of high pure esters, but they usually behave low catalytic activity due to denaturation and aggregation of enzyme protein in organic phases. To improve the nonaqueous catalysis, the inexpensive copper phthalocyanine was taken as a new carrier on which Pseudomonas cepacia lipase was immobilized by physical absorption, and used for synthesis of hexyl acetate, an important flavor, via transesterification of hexanol and vinyl acetate. Results showed that the desired loading was 10 mg lipase immobilized on 10 mg copper phthalocyanine powder. When the immobilized lipase was employed in the reaction system consisted of 1.5 mL hexanol and 1.5 mL vinyl acetate at 37℃ and 160 rpm, the conversion was five fold of that catalyzed by native lipase after 1 h, and reached 99.0% after 8 h. Undergoing six times of 8-h reuses, the immobilized lipase had an activity attenuation rate 1.22% h− 1, lower than 1.77% h− 1 of native lipase, which meant that the immobilized lipase was more stable. Even at the room temperature and the static state without shaking or stirring, the immobilized lipase could bring conversion 42.8% after 10 h and the native lipase gave 20.1%. Obviously, the immobilized lipase is an available biocatalyst in organic phase and has great potential in food industry.