Efficiency Analysis of Spark Ignition Giogas Genset for Electricity Power Generation

This research studied the influence of the ratio of load and maximum power of genset and usage time to the efficiency of electricity energy conversion using biogas as fuel. The experiment was done in Biogas Power System installed by Puslit Telimek LIPI in Baiturrahman Islamic Boarding School, West Java, Indonesia. The electricity energy was generated using modified Spark Ignition gasoline genset so that it can be fueled with 100% biogas. Genset efficiency was calculated based on genset load and thermal power of biogas consumed by the genset. The result showed that the genset efficiency is increased with the increasing of load and maximum power ratio. Usage time also significantly decreased the genset efficiency for biogas fuel without CO2, H2S, and water purification. For 5 kW new genset with 40% load, the average efficiency can reach 42.20%. Genset 2.5 kW with usage time 8 years has lower average efficiency as much as 11.76% for 40% load and 5.50% for 20% load. The efficiency of new genset is significant high, so that SI genset very potential to be implemented in a biogas system. To reach higher efficiency, purification process is needed especially to remove the CO2, H2S, and H2O

ANIMASI IKLAN LAYANAN MASYARAKAT TENTANG REDENOMINASI MATA UANG RUPIAH

Akhir tahun 2012 masyarakat di hebohkan dengan rencana Redominasi rupiah. Dalam rangka menciptakan sistem pembayaran yang efisien, cepat, aman, dan handal Bank Indonesia melakukan suatu kebijakan yang disebut redenominasi.Adapun alasan yang melatarbelakangi Bank Indonesia melakukan redenominasi mata uang rupiah adalah karena munculnya keresahan atas status rupiah yang terlalu rendah ketimbang mata uang lainnya, pecahan uang Indonesia yang selalu besar akan menimbulkan ketidakefisienan dan ketidaknyamanan dalam melakukan transaksi, untuk mempersiapkan kesetaraan ekonomi Indonesia dengan kawasan ASEAN dalam memasuki era Masyarakat Ekonomi Asean pada tahun 2015. Dari latar belakang itulah penulis ingin membuat iklan layanan masyarakat tentang Redenominasi, dengan harapan bisa membantu masyarakat memahami apa itu redenominasi. Manfaat iklan yang terbesar adalah membawa pesan yang ingin disampaikan oleh produsen kepada khalayak ramai. Manfaat iklan yang terbesar adalah membawa pesan yang ingin disampaikan oleh produsen kepada khalayak ramai. Perancangan Animasi iklan layanan masyarakat menggunakan Adobe Flash CS 5 ini dipilih, karena bisa di Aplikasikan di televisi. Selain itu, penulis memilih membuat animasi dua dimensi (2D), karena animasi dua dimensi lebih bersifat informatif. Dibandingkan animasi tiga dimensi (3D) yang cenderung perfeksionis dan realistis (M.S Gumelar). Mengenai hal itu penulis tertarik untuk membuat iklan layanan masyarakat bertemakan tentang redenominasi di Indonesia dengan mengandung unsur animasi 2D. Yang bertujuan untuk membantu menginformasikan kepada masyarakat agar bisa memahami apa itu redenominasi

Estimation of Oxygen Concentration in the Slurry in Biogas Production Without O2 Removal in Initial Process

AbstractThe existence of free molecular oxygen in the biogas production process will inhibit strict anaerobic methanogenic bacteria. The estimation of O2 concentration in the slurry is needed to see if the oxygen methanogenic inhibition happens in the biogas production without oxygen removal in initial process. The calculation begin with determine the digester volume, the gas space volume fraction in the digester, and the operation condition, i.e. the temperature and the pressure according to the good condition in the biogas production process. Based on the liquid-gas equilibrium principle, and with the assumption that the air consist of 80% of nitrogen and 20% of oxygen, it is obtained the equilibrium oxygen concentration in the slurry in various gas space volume fraction in the digester. The result of the calculation show that the oxygen concentrations in the slurry in all of gas space volume fraction in the digester are much higher than the methanogenic inhibition limit, indicating the possibility the happen of the methanogenic inhibition in the system. The inhibition possibility will be higher by the greater of the gas space volume fraction in the digester

Analysis of Product and Temperature of Biogas Combustion in Various Air Biogas Equivalence Ratio and Methane Content

Biogas resulted from anaerobic digestion of organic compounds have various methane content depend on the type of the degraded material. The methane content of biogas is range between 40–80% that influence the heating value and combustion characteristic of that biogas. The higher methane content can be obtained through upgrading biogas by removing CO2 and other trace components like H2S, NH3, and water vapor. This research was a simulation of product composition and temperature of biogas combustion in various methane content and air biogas equivalence ratio. Biogas combustion was done in combustion chamber at constant pressure of 1 atm. Biogas and air enter into combustion chamber at temperature approximately of 30 °C as the common ambient temperature in Indonesia. The input air was designed higher than stoichiometric need in order to reach complete combustion. Combustion reaction between methane and O2 then carried out in the combustion chamber to produce CO2 and H2O. The product gases consisting of CO2, H2O, N2, and excess O2, bring heat from combustion reaction and exit from combustion chamber at the higher temperature. The analysis was done for methane content range between 20 and 100% with air biogas equivalence ratio from 1 until 3. The simulation result showed that for V m3 biogas, the combustion gases could reach 0.12271 until 1.26798V gmol with temperature above 700 °C until above 1900 °C. More than 50% component in the combustion gases is N2 as inert material from input air to combustion chamber

The Effect of the Addition of Active Digester Effluent for Start-up Accelerator in Anaerobic Digestion of Soybean Curd Industry Waste Water (Basic Research for Biogas Power Generation)

Biogas production from soybean curd industry waste water was studied in laboratory scale to improve the application of anaerobic digestion process. The problem with the soybean curd waste water was the fact that it does not sufficiently contain anaerobic microorganisms required in biogas production. Therefore, it is necessary to add a well-developed population of anaerobic microorganisms to accelerate the start-up of the anerobic digestion. This research was aimed to verify the influence of the addition of active digester effluent into the soybean curd waste water batches in an anaerobic digestion process. Batch experiments were done in two digesters. The first digester was only fed with soybean curd waste water while the second digester was fed with soybean curd waste water and active digester effluent from a digester processing cow manure which was very rich in anaerobic microorganism consortium. The results indicated that soybean curd industry waste water did not contain methanogenic bacteria but there existed some acidogenic bacteria. The addition of active digester effluent accelerated the anaerobic digestion start-up and directed the process pathway towards methanogenic process so that more methane was obtained. The high methane content obtained (more than 64% volume) was very potential for power generation. The capacity of soybean curd industry must be as high as 697.13 kg soybean per day to generate the electric energy of 8.4 kWh

PEMBUATAN BIOGAS DARI CAMPURAN AIR LIMBAH TAHU DAN KOTORAN SAPI MENGGUNAKAN BIBIT MIKROBIA PEMICU DARI SLURRY KELUARAN DIGESTER AKTIF

The aim of this research was to study the influence of various variables on anaerobic co-digestion process of tofu waste water and cow manure, i.e. the influence of the addition of active digested sludge as a starter, the influence of O2 removal at the initial process, the influence of the amount of tofu waste water, cow manure, and active digested sludge, and the influence of the feeding strategies of tofu waste water on biogas production and methane yield. Batch and fed batch experiment was done in a closed digester. Batch experiment was started with putting the tofu waste water, cow manure, and active digested sludge with a certain ratio to the digester, and mix its until homogen. Nitrogen gas was flushed into digester, the digester was closed, and the process was run. Fed batch experiment was started with putting cow manure and active digested sludge to the digester, and after process occur, tofu waste water fed in to the digester periodically. In both experiment the formed gas volume was noted every day and at certain times gas and slurry was taken from the digester for analysis purposes. The result of this research showed that the addition of active digested sludge as a starter could cause a formation of methane on biogas production from tofu waste water. The addition of digested sludge of 1/3 total material weight would shorten more than 50% production time. The presence of little O2 at the initial process had no significant effect on gas production and methane yield. The good weight ratio of tofu waste water, cow manure, and active digested sludge was 3 : 1 : 2. In the right composition, mixing tofu waste water as a co-substrate with cow manure would increase biogas production from cow manure, and feeding tofu wastewater frequently would reduce methane production