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The high use of fossil fuels in the ironmaking industry leads to CO2 emissions. This study investigates the potential of using biomass as a fuel and reducing agent for iron ore reduction. The reduction process was conducted non-isothermally up to a set temperature, followed by isothermal treatment for 60 minutes. The thermogravimetric analysis of the pellets revealed that the weight loss and CO and CO2 composition increased with temperature, indicating higher reduction reactivity. The kinetic model developed from solid-state and two-parallel reaction equations, using TGA data, showed that Fe2O3 → Fe3O4 and FeO → Fe were the most influential reactions at temperatures of 800°C and above. Furthermore, laboratory experiments analyzed the effluent gas. The results suggest that biomass is a promising alternative to fossil fuels in the ironmaking industry, reducing CO2 emissions, and enhancing the efficiency of the reduction process. [ABSTRACT FROM AUTHOR]

CFD simulation has been proven to accelerate the construction process of better biomass furnace and to find the optimum condition of biomass combustion. Optimum furnace design and operating condition can lead to better energy conversion with less pollution level. This work is aiming to formulate CFD model that can accurately predict the biomass combustion behavior inside a grate-fired biomass furnace. CFD simulation results then compared with experiment result which has been conducted using coconut shell as fuel. The distributed pyrolysis products based on atom and heat balance is utilized in the current work. The distributed pyrolysis products model gives reasonably good estimation of the volatile matter components and its composition in different pyrolysis temperature condition. Accurate prediction of the biomass combustion behavior from the proposed CFD model are depicted by high degree of similarity of several combustion parameters compared to the experimental observation i.e., temperature throughout the furnace and CO2 level of flue gas. The experimental observation give the CO2 level percentage from flue gas of 9.59±0.35 while current simulation produce the CO2 level percentage of 9.85. The relative error of temperature in furnace and CO2 level between current work and experimental observation have reached to be below 3% which is acceptable. Moreover, the proposed CFD model allows to estimate parameters which are hard to observe experimentally e.g., temperature distribution, local oxygen content, and volatile matters conversion. The established model allows further biomass combustion simulation in combination with pollutant formation which finally can be exploited to design the better furnace and better combustion condition. [ABSTRACT FROM AUTHOR]

Levulinic acid (LA) is a short-chain fatty acid with ketone and carboxylic acid group which gives it superior characteristics as a building-block chemical for producing various chemicals, such as: Ƴ-valerolactone (GVL), methyltetrahydrofuran (MTHF), diphenolic acid (DPA), delta-aminolevulinic acid (DALA), and levulinate ester. Levulinic acid can be synthesized from various kinds of biomass and its derivatives, one of which is glucose. The reaction route of glucose hydrolysis to LA generally involves intermediates such as fructose, levoglucosan, and HMF, depending on the type of catalyst used. In this study, simulation of the kinetics of the hydrolysis reaction of glucose into LA was performed by simplifying the reaction scheme from reference data. The variables studied were temperature (140-160 oC) and concentration of hydrochloric acid catalyst (0.5-1.5 M). The hydrolysis data were simulated with three different models using MATLAB 2018a. The function of ode45 was used to solve the differential equations and fminsearch tool was used to minimize the kinetic parameter values. Chang's model produces a greatest mean R2 (closer to one), which is considered more suitable than Mikola and Liang's model. [ABSTRACT FROM AUTHOR]

The membrane separation technique is an alternative for separating compounds with a simple operation process, lower cost, and lower energy consumption. This research was purposed to purify the proanthocyanidins from the extract of red sorghum pericarp using an ultrafiltration membrane and to evaluate the membrane characteristics in the purification of proanthocyanidins. The ultrafiltration process was carried out by the dead-end cell method using two sizes of Polyethersulfone (PES) membrane with a different Molecular weight cut-off (MWCO) involved 30 kDa at a pressure of 4-6 Bar and the one 10 kDa at a pressure of 8-10 Bar. The total phenolic content (TPC) was analyzed using the Follin-Ciocalteu method, while the proanthocyanidin was analyzed using the butanol-HCl assay method using the Uv-Vis Spectrophotometry. The results showed that the higher operating pressure applied in the process caused the higher increase of the proanthocyanidin concentration and the permeate flux, but the lower in the selectivity or the rejection of the membrane. [ABSTRACT FROM AUTHOR]

Lignocellulosic biorefinery is a promising alternative for petroleum refinery that has potential to meet a sustainable variety of needs in the future. One product of lignocelullosic biorefinery is levulinic acid (LA) which is a precursor for the production of many chemicals. Cellulose from lignocellulosic biomass is hydrolyzed to glucose, then hydroxymethylfurfural (HMF), and subsequently to LA. In this paper, the starting material was glucose, as a part of large LA synthesis project from biomass in the form of sugarcane bagasse. Glucose was reacted using 0.5 - 1.5 M hydrochloric acid catalyst at temperatures of 160 - 180 °C. From the experiments, it was found that the higher the temperature and concentration of the catalyst, the higher the LA yield. However, a combination of excessively high temperature and catalyst concentration will reduce the LA yield. [ABSTRACT FROM AUTHOR]

Unit transformation in public housing provided by the Indonesian government has occurred constantly over time and is expected today. Unfortunately, the transformation process rarely involves housing experts, thereby frequently leading to environmental quality decreasing, such as sacrificing a house’s thermal comfort. Previous research has recommended courtyards to be included as (part of) the additional room program in the transformation. This article aims to examine the dimension and form of a courtyard which is optimal for maintaining wind flow inside the house. The research was conducted using a Computational Fluid Dynamic (CFD) simulation. The simulated unit models have developed versions of the initial design (Type 36). The courtyard that is placed in the middle of the back area of a house is based on the previous research conclusion which states such a location is one of the best spots for inducing wind inside the house. The simulation was run twice, with 2 slightly different sized courtyards, but in different positions to figure out the most effective one. In summary, it can be concluded that the transverse courtyard is more effective in maintaining appropriate levels of wind movement inside the house. Such a courtyard may not need to be wide; hence it will be beneficial as the residents can use the area for other purposes. [ABSTRACT FROM AUTHOR]

The supercritical fluid extraction is the most effective and efficient way to extract valuable constituent in botanicals but the apparatus is usually very complex, complicated and expensive. Carbon dioxide gas needs to be pumped and pressed to reach its supercritical pressure. In this research, the supercritical CO2 condition was achieved by sublimation of a certain amount of dry ice (CO2 solid). The achieved pressure depends on the mass of dry ice. By developing supercritical extraction technology using this dry ice, the apparatus becomes simpler so the price becomes less expensive. Since this method is also able to be operated in a batch operation, the equilibrium data could be obtained. The objective of this research was to design of supercritical fluid extraction apparatus using dry ice as a supercritical solvent. The designed apparatus consisted of 2 main vessels. The first one was a high-pressure extractor for extracting process using supercritical CO2 solvent. The second one was a separator vessel for separating solvent and extract. During the experiment, the gas leakage of the high-pressure apparatus often occurred. To avoid the leakage, the valves and pipes used the standard brands of Swagelok and Sanvik. Similarly, the design of extractor cover used o ring with silicone rubber material. The leakage that occurred during high-pressure operations was very dangerous. To ensure safety, installation of series of apparatus was covered by perforated iron with 2 pieces of windows made of an acrylic material to facilitate in monitoring the process. In this research, the correlation of the dry ice mass and the achieved pressure at a temperature of 40 °C was also studied. The Equation of State (EOS), such as Ideal Gas, van der Waals, Redlich Kwong, Soave-Redlich Kwong, and Peng Robinson were explored to predict the operating condition (supercritical pressure and temperature). By comparing the calculated pressure at various Equation of State and the experimental data, the Peng Robinson was the most appropriate Equation of State. [ABSTRACT FROM AUTHOR]

An alternative process for producing NP fertilizer is melt granulation. To design prilling tower for this granulation, binary solid-liquid phase equilibrium of Urea-MAP is needed. This research focuses on developing a solid-liquid binary phase diagram. Phase diagram of binary system was constructed based on ideal model from the pure components and compare to experimental by Differential Scanning Calorimetry (DSC). Phase diagram of Urea-MAP was observed to form a simple eutectic behaviour with the eutectic temperature is 112.2°C and the eutectic composition is xurea 82.2% mol. Experimental data were used to adjust the parameters of Wilson models and the results showed that this model can appropriately describe the liquidus lines of Urea-MAP systems. Using phase diagrams of the Urea-MAP, it will be easier to know the phase conditions in each composition, to determine the best operating temperature to melt Urea-MAP mixture, to find out physical properties of thermal, and also as basis to design prilling tower. [ABSTRACT FROM AUTHOR]

Limonene and eugenol are known as microbial inhibitory agents towards some fermentative microbes including those which are responsible for converting polysaccharides into hydrogen (H2) and carbon dioxide (CO2) through dark fermentation method. This research was meant to investigate the inhibitory kinetics of those two components i.e. Limonene and Eugenol toward a mixed culture of dark fermentative biohydrogen production. The operating condition was set at a temperature of 37°C, the pressure of 1 atmosphere, and initial pH of 5.0. Experiments were run using glucose as solely substrate at a various concentration of limonene and eugenol to investigate the effect of their concentration. Study of inhibitory kinetics was conducted using a novel model of General 3-Parameters Gompertz to determine the type of inhibition namely competitive, non-competitive and uncompetitive inhibition. It was figuring out that the effect of concentration of both components was evident that the increasing value of concentration, the lower biohydrogen gas production rate. It signifies that the fermentation was partially inhibited. Based on the kinetics model, the non-competitive model was truly fitted with the profile of biohydrogen production rate which implies that glucose as substrate and limonene/eugenol as inhibitor could attach to the microbial cell as bio-enzymes at the same time. Due to the interaction between inhibitor and cell wall of microbes which suspected to cause membrane disruption, the metabolism of the cell decreased leading to lower production of hydrogen. This study shows that dark fermentative biohydrogen production can face inhibitory problems when utilizing limonene- and/or eugenol-contained organic substrates such as citrus waste and melon waste at the mesophilic condition. This phenomenon might be mitigated through encapsulation of microbial mixed culture to reduce the interaction, eliminating the two inhibitory components, and maintaining the inhibitory concentration at the lowest possible values. [ABSTRACT FROM AUTHOR]

Gasification is a thermal process involving the interaction between physical and chemical processes. Thus, it is necessary to understand the operating conditions in the design and operation. The optimum conversion of the solid fuel to the desired gas will depend heavily on the configuration, size and selection of gasifier operating condition. Optimum operating conditions can be obtained through research on existing plants or testing on a particular equipment. In addition, the optimum conditions can also be obtained through mathematical modeling. Although it cannot provide very accurate results, this method can provide clues about the quantitative effects of design, raw materials and other operating parameters. Representation of the gasification process in the form of mathematical equations can also help understand the importance of the effect of operating parameters on the performance of a gasifier and can provide a good understanding of the mechanisms that occur. Gasification involves mass transfer events and chemical reactions. The kinetic equations constructed in the gasification process are mostly based on heterogeneous (solid-gas) reactions whereas in gasification reactions and there is also a homogeneous reaction (gases). It is therefore necessary to prepare a kinetic calculation involving heterogeneous reactions and homogeneous reactions. Random Pore Model was first proposed by Bhatia and Perlmutter. The model uses the assumption that char consists of cylindrical pores with a random size distribution. The rate of heterogeneous reactions, which take place on the contact surface of solid and reactant gas, are dominated by the inner surface area of the pores. The diameter of the pores also influences the transportation of the reactant gases into the solid and the resultant gases out of the solid. The homogeneous reactions are those among gas species; both volatile gases and gasification agent gases reactions include water gas shift reaction. The developed model for the steam gasification of solid chars has been solved under the operating temperatures of 600oC, 700oC and 800oC as used in this experiment. The model has been solved in MATLAB software using a numerical technique. [ABSTRACT FROM AUTHOR]

In the pyrolysis process, tar material may cause operational problems such as pipe plugging, condensation, and tar aerosol formation. Unusual approaching should be introduced to solve carbon deposition over catalyst which was serious problem in tar decomposition process. Porous low-grade iron ore was promising candidate due to cheap material, non-toxic and the carbon deposition could be utilized on ironmaking process. The liquid tar was introduced on the fixed bed of porous ore in the quartz tube reactor with N2 atmosphere at different temperature (500-700°C). Decomposition of tar exhibited similar profiles of H2 and CO generation which was rising shortly after starting the experiment because ore catalyst still owned high activity and no carbon poisoning. However, the excessive carbon deposition was also occurred simultaneously in the beginning of experiment and caused deactivation of ore catalyst. It means that the carbon deposition within pores ore affected highly to catalyts activity. However, the high carbon content within inactive ore catalyst offered extra benefit in the steel production as raw material by exhibiting high reactivity and lower temperature in reduction process. Therefore, the tar decomposition over porous iron ore was promising catalyst which was cheap, natural resource and reuse of inactive material. [ABSTRACT FROM AUTHOR]

The usage of biogas as vehicle fuel has been developed in the last two decades. Consequently, the upgrading technologies for biogas grow up rapidly. One of technologies that is considerably cheap and simple is the water scrubbing system. This method will yield clean biogas with methane content at least 95%. It is well-known that the composition and flow rate of biogas produced by anaerobic digester commonly fluctuates. Therefore, successful absorption requires a suitable process control. It can be achieved by designing an appropriate control strategy. This control design can be obtained properly if the dynamic behaviour of the system is determined. In this study, Chemcad Dynamic Simulation Software was employed to determine the dynamic behavior of biogas water scrubbing system. In addition, the dynamic performance of absorption system in connection with the disturbances in composition of raw biogas feed, temperature, and pressure of absorption column was studied as well. Based on the simulation results, the flow rate of water solvent had significant impact to the purity of the product when there were variations of the flow rates and compositions of raw biogas. For absorber model with 20 ideal plates, the optimum ratio for liquid-gas feed was 9.1789. This ratio generated product that matched to the minimum requirement of purified biogas for vehicle fuel application even though the methane content of raw biogas feed oscillated from 50 to 70%. Other parameters such as pressure and temperature had minor impacts on the dynamic performance. Pressure changes of the feed also had insignificant influence to the simulation while the temperature of water solvent gave noises in the beginning of the simulation. [ABSTRACT FROM AUTHOR]

Supercritical Fluid Extraction (SFE) is the process of separating a soluble material from an insoluble residue using the supercritical fluid as the extracting solvent. This extraction is the most effective and efficient way to extract valuable constituent in botanicals. Supercritical carbon dioxide is a fluid state of carbon dioxide that is held above its critical temperature (Tc=31.1 °C) and critical pressure (Pc=73.8 bar). It is a natural solvent and has been widely used in practical applications because of its non-toxic, non-flammable, plentiful, inexpensive and tunable of solvent properties by just adjusting temperature and pressure. Due to carbon dioxide's relatively low critical temperature, it is especially suitable for processing thermo-labile compounds, such as pharmaceutical and nutraceutical compounds. Nevertheless, the cost of SFE equipment is outside the range of most of our finances. A high-pressure intensifier pump is used to achieve the required pressure. In this research, the supercritical CO2 condition was achieved by other alternative using dry ice. It is a solid phase of CO2 when frozen. At standard temperature and pressure (STP), CO2 usually behaves as a gas. If dry ice is put in an enclosed vessel, it will sublimate to become a gas and the pressure will increase depending on the mass of dry ice until the desired pressure (supercritical pressure) is achieved. By supercritical CO2 from dry ice, the equipment of SFE will be simpler and cheaper. It is also suitable for batch operation to get equilibrium data of supercritical fluid extraction. Exploration of Equation of State, such as Ideal Gas, van der Waals, Redlich Kwong, Soave-Redlich Kwong and Peng Robinson, was done to predict the operating condition (supercritical pressure and temperature). In this research, by comparing the calculated and the experimental data, Peng Robinson is considered as the most appropriate Equation of State. [ABSTRACT FROM AUTHOR]