No abstract

Bio-desulfurization generally involves the oxidation of sulfide to sedimented, sulfur compounds in microaerobic conditions and is applied at biogas power plants by the palm oil industry. In this work, microbes were screened from various sources, including microalgae, coal waste, Palm Oil Mill Effluent (POME), and cow manure. Screening of potential microbes was conducted using synthetic chemical reagent as the sulfur source. Decomposition of sulfur sources, like Na 2 S 2 O 3 , has been observed through microbial process whereas sulfur was separated into sedimented other sulfur compounds. Screenings were first conducted in modified growth media followed by screening with selective media for Thiobacillus. With the selective media, the treatment was continued with the addition of a sulfur source to see if the microbes are able to convert the sulfur to sulfuric acid or other sulfur compounds as sediment. The preferred microbe would be chosen and applied to the bioscrubber system at Terantam, Indonesia. This work could also be applicable to biogas generation from POME where H 2 S content is more than 1,200 ppm, which is corrosive to the biogas engine. Finally, we propose a two-step desulfurization in which H 2 S is absorbed by an alkali solution followed by sulfur separation.

Along with population growth and its activities, in business-as-usual approach, the energy needs to support these activities will be even greater. Up to this point, the fulfillment of energy sources is still dominated by fossil fuels. Therefore, innovation and technology development explore all potentials related to, especially, renewable fuel. Hydrogen (H2) is a potential energy carrier with an energy content 2.75 times higher energy than hydrocarbon fuels. Previous research using Palm Oil Mill Effluent (POME) as a raw material has been carried out on 2.5 dm3 and 40 dm3 scales. Based on these results, a scaling-up system was designed as a bio-Continuous Stirred Tank Reactor (CSTR) for the production of H2 from a capacity of 900 dm3 by modifying the existing reactor. The bio H2 production system was designed by considering the feed stream will flow from the bottom and stream up through high concentration activated sludge which will decompose the organic content in POME. POME flow up and out through the overflow pipe. Meanwhile, the biogas, H2 and CO2, will flow through the upper pipe and be channeled to the biogas holder. POME feeding is designed to inflow up laminar so that POME decomposition occurs gradually as indicated by the decreasing COD and BOD values at the bottom and overflow. The difference in COD and BOD concentrations in the bio-CSTR shows a positive effect on the 1 m 3 bio-CSTR. The bio CSTR was equipped with impellers in 4 different levels to maintain uniformity at each level. Thus the form of POME flow is laminar and non stagnant. The result showed COD decreased between the bottom and the overflow reached 5280 ppm. In addition, the pH only changes to a maximum of 0.1. Both data indicated that biological processes working well and do not influence the operational condition Novelty: This bio CSTR design for biogas H2 production is a modification of an existing bio H2 production system that uses POME as raw material and has a working volume of around 1 m3 (1000 liters). The previous system mixed with the bottom functioning on top by using circulation in the bioreactor. There hasn't been any decent data on H2 biogas production until recently. Modification of the H2 biogas production system is carried out by adding a stirring system that works in a laminar flow -non stagnant. Another added feature is the heating system for pretreatment, which can be used both for conditioning the seeding culture consortium biogas H2 and for the preparation of feeding into bio-CSTR. A diaphragm pump that can work for sludge is also included in the system. Currently, research on the maximum H2 biogas production is being carried out on a 2.5 liter scale 1). Novelty in this research is to design a bio CSTR on a scale of 1 m 3 which can also be utilized to produce H2 biogas from POME.

Production of biodiesel has been conducted through several processes such as esterification andtransesterification by homogeneous catalyst in which use either acidic or alkaline substances.Homogeneous catalysts have some negative impacts to the environment, because technically itrequires further treatment process such as washing. Therefore, the use of heterogeneouscatalysts is proposed to be best way to overcome this problem. The advantages of heterogeneouscatalysts are not only for its ease in recovery but also for its reusability. Moreover, it isenvironmentally friendly and cheap which only undergo a single process of transesterification.Calcium oxide is well-known as one of heterogeneous catalysts. It were activated by pretreatmentwith methanol and then it was continued by transesterification reaction. The optimal reactiono conditions were obtained at temperature 60 C, atmospheric pressure, and 4 h reaction time.Calcium oxides shows good activity in transesterification reaction using either palm or jatropha oil.The highest conversion of palm oil is approximately 62,51% within catalyst 3% by weight oil,whereas jatropha oil is approximately 53.10 % within catalyst 10% by weight oil. The regeneratedcatalyst shows low catalytic activity which is indicated by small presence of methyl ester in theproduct.Key words : biodiesel, heterogen catalyst, calcium oxide, palm oil, jatropha oil

Catalyst activation is an important step in methanol synthesis process, achieved by the reduction of CuO precursor producing Cu0 active sites.  Testplant’s temperature operation shall be maintainted at 220°C in order to maximize the CuO reduction process in the catalyst activation step. A temperature control system shall be applied in methanol testplant to maintain the temperature during reduction process, due to sensitivity of reduction process to temperature variation and possibility of disturbance such as change in gas flow rate which could affects the operating temperature. Temperature control systems are tested by using step response at the desired setpoint, which is 220°C at pre-heater and reactor and 60°C at sampling line. The tests are conducted by changing the setpoint value at temperature controller and previously stable flow gas in the system (disturbance rejection). The temperature control system proved to be able to response well during the test. In the end, methanol is produced from syngas, indicating catalyst activation success. Keywords: Catalyst Activation; Methanol Testplant; Temperature Controller