Jurnal Reaktor

131-139

Authors: Istadi Istadi, Luqman Buchori, Suherman Suherman

The plastic waste utilization can be addressed toward different valuable products. A promising technology for the utilization is by converting it to fuels. Simultaneous modeling and optimization representing effect of reactor temperature, catalyst calcinations temperature, and plastic/catalyst weight ratio toward performance of liquid fuel production was studied over modified catalyst waste. The optimization was performed to find optimal operating conditions (reactor temperature, catalyst calcination temperature, and plastic/catalyst weight ratio) that maximize the liquid fuel product. A Hybrid Artificial Neural Network-Genetic Algorithm (ANN-GA) method was used for the modeling and optimization, respectively. The variable interaction between the reactor temperature, catalyst calcination temperature, as well as plastic/catalyst ratio is presented in surface plots. From the GC-MS characterization, the liquid fuels product was mainly composed of C4 to C13 hydrocarbons.

148-154

Authors: Praswasti Pembangun Dyah Kencana Wulan, Widodo Wahyu Purwanto, Yuswan Muharam

The main focus of this research was to obtain micro kinetics decomposition of methane producing carbon nanotube on the surface of the Ni-Cu-Al catalyst. Experimental kinetics data collected at a temperature range of 650-750oC and pressure of one atmosphere. The preliminary test was conducted to obtain the kinetics are not influenced by external and internal diffusion limitations as well as inter-phase transfer. Kinetics data were tested by micro kinetic model derived from the catalyst surface reaction mechanism. The most appropriate kinetic model becomes the rate-limiting step of methane decomposition reaction. Results of preliminary experiment showed that the kinetics of the external diffusion effect is negligible at flow rates above 150 mL/min. Internal diffusion can be ignored with a catalyst under 0.25 mm in diameter with a weight of 0.04 grams of catalyst and contact time 2.5x10-4. Rate equation analysis shows that the rate-limiting step is the adsorption which indicates that intermediate consumption (CH4I + I Û CH3I + HI) is faster than the formation of intermediate (adsorption of methane, CH4 + I Û CH4I). The activation energy obtained for 34.628 kJ/mol and pre-exponential factor of 6.583x106.

165-171

Authors: Bambang Cahyono, Muhammad Diah Khoirul Huda, Leenawaty Limantara

Curcuminoid a yellow coloring agent of turmeric is known to have many benefits in food and medicinal industries. This compound can be isolated by simple extraction from fresh rhizome or symplicia. The research of comparing qualitative and quantitative of curcuminoid in different drying process has not yet been published. Drying methods used in this research were done in an oven at 60°C and under 30-watt electrical lamp at ±30°C. Each method was carried out in time variation of 1, 3, and 5 days. Extraction of curcuminoid was done using ethanol 95% followed by fat reduction process using petroleum ether. Curcuminoid analysis was done by TLC, UV-Visible spectrophotometer and HPLC. The result showed that the water content of all samples was approximately 4.06%-7.76%. TLC analysis identified the presence of two dominant components in the curcuminoid with the Rf values of 0.37 and 0.15. The UV-Visible spectra indicated that simplicia would give more result in curcuminoid than fresh rhizome. There were 4 substances detected in HPLC analysis, they were curcumin 61-67%, demetoxycurcumin 22-26%, bisdemetoxycurcumin 1-3%, and curcuminoid derivative 10-11%. In addition, drying on oven resulted brighter and crispier simplicia than drying under lamp.

178-184

Authors: Laeli Kurniasari, Mohammad Djaeni, Aprilina Purbasari

Drying is one process which is used in many industries, especially in food product. The process usually still has low energy efficiency and can make food deterioration because of the usage of high temperature. One alternative in drying technology is the use of zeolite as a water vapor adsorbent. This kind of drying method make it possible to operate in lower temperature, hence it will be suitable for heat sensitive product. Natural zeolit can be one promising adsorbent since it is spreadly abundant in Indonesia. Natural zeolite must be activated first before used, in order to get zeolite with high adsorption capacity. Activation process in natural zeolite will change the Si/Al ratio, polarity, and affinity of zeolite toward water vapor and also increase the porosity. Activation of natural zeolite can be done with two methods, chemical activation use NaOH and physical activation use heat. In the activation using NaOH, natural zeolite is immersed with NaOH solution 0.5-2N in 2 hour with temperature range 60-900C. The process is continued with the drying of zeolite in oven with 1100C for 4 hours. While in heat treatment, zeolit is heated into 200-5000C in furnace for 2-5 hours. SEM analysis is used to compare the change in zeolite morphology before and after each treatment, while to know the adsorption capacity of zeolite, the analyses were done in many temperature and relative humidity. Result gives the best condition in NaOH activation is NaOH 1N and temperature 700C, with water vapor loading is 0.171 gr/gr adsorbent. In heat treatment, the best condition is 3000C and 3 hours with loading 0.137 gr water vapor/gr adsorbent.

194-200

Authors: Kristinah Haryani, Widayat Widayat

Citric acid is an important organic acid that has many advantages used in foods, drinks, pharmaceuticals industries. Waste of pine apple (covers and core of the fruit) still have high contents of glucose and sucrose components, that these are potentially used as basic material for making citric acid by means of fermentation using Aspergillus niger. The reactor to do so is a reactor air-lift external loop with 88 cm in height, 45.41 cm2 in riser area, and 2.01 cm2 in downcomer area. This research is intended to study the influence of volumetric flow and viscosity upon mass transfer in the fermentation process of citric. The variable factors are concentration of total sugar (5 to 25%) and of volumetric flow of gas 9.4 to 23.3 cc/second. A dynamic method used to measure of the constants transfer of gas-fluid mass where oxygen concentration soluted is measured every 30 second using DO meter device. Result of this research shows that the increase of viscosity causes the decrease of hold up gas and fluid circulation speed of the fluid, and the decrease of the constants of mass transfer. The increase of air speed flow will cause the increase of hold up gas and fluid circulation speed, and constants of mass transfer. Relation of the constraints of mass transfer to volumetric flow and viscosity is formulated as follow