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Istadi Istadi
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Chemical Engineering, Chemistry & Bioengineering Control & Systems Engineering Energy Engineering Materials Science & Nanotechnology Mechanical Engineering

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The moving-slab Heating in the furnace for various production plans Istadi Istadi; Y. Bindar; Koswara Koswara
Reaktor Volume 6 No. 1 Juni 2002
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4978.075 KB) | DOI: 10.14710/reaktor.6.1.1-7

Abstract

The reheating furnace in occasional production time has to be charged with slabs having fifferent sizes in length, ridth and thickness. This production plan was put due to economical and productivity consideration. Moreover in the future development, the slab grade might be improved to hight grades. It is our expectation that the furnace can be fire for different production plans above. The strategy for firing the burners from zone to zone has to  be determined precisely to meet the designed heating curves for the various slab. A suggest to guide in the formulations of the furnace firing strategy was developed in this work. This suggestion is based on three-dimentional mathematical model for heated slab in the furnace. This mathematical model was coded  for the computational simulation. The  code was able to simulate  furnacthree-dimentional effect of fuenace operational parameters and variety of slab length group. The result reasonably represent the slab-heating curve for different operational parameters. Unsymmetrical firing practices can be shown their effect to the 3D temperature distribution of the slab. Keywords : 3Dtemperature distribution, reheating furnace, slab heating, slab length group
MODEL HETEROGEN PENGERINGAN BUTIRAN JAGUNG DALAM UNGGUN DIAM Istadi Istadi; J. P Sitompul
Mesin Vol. 15 No. 3 (2000)
Publisher : Mesin

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Abstract

This paper deals with one-dimensional dynamic modelling and simulation of deep -bed com drying by two-phase model or heterogeneous model The models consider mass and heat transfer process within grain and drying air phase. This model also considers moisture content and temperature gradient within grain. The coupled of partial differential equations developed, then solves numerically by finite difference with altemating direction implicit method algorithm. The dynamic models predict not only humidity and temperature of outlet drying air, but also grain moisture content and temperature. The simulated profiles are compared with expenmental data, taken from available literature. The models can describe corn grain drying process in deep -bed dryer. However, the model parameters should be modified to get drying characteristic profiles that closed to the experimenal data.
UNJUK KERJA REAKTOR PLASMA DIELECTRIC BARRIER DISCHARGE UNTUK PRODUKSI BIODIESEL DARI MINYAK KELAPA SAWIT Ardian Dwi Yudhistira; Istadi Istadi
TEKNIK Vol 34, No 2 (2013)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (352.376 KB) | DOI: 10.14710/metana.v%vi%i.5636

Abstract

Biodiesel is one of alternative renewable energy source to substitute diesel fuel. Various biodiesel productionprocesses through transesterification reaction with a variety of catalysts have been developed by previousresearcher. This process still has the disadvantage of a long reaction time, and high energy need. DielectricBarrier Discharge (DBD) plasma electro-catalysis may become a solution to overcome the drawbacks in theconventional transesterification process. This process only needs a short time reaction and low energy process.The purpose of this study was to assess the performance of DBD plasma rector in making biodiesel such as: theeffect of high voltage electric value, electrodes gap, mole ratio of methanol / oil, and reaction time. TheResearch method was using GC-MS (Gas Cromatography-Mass Spectrofotometry) and FTIR (FourierTransform Infrared Spectrofotometry) and then it will be analysed the change of chemical bond betweenreactant and product. So, the reaction mechanism can be predicted. Biodiesel is produced using methanol andpalm oil as reactants and DBD plasma used as reactor in batch system. Then, reactants contacted by highvoltage electric. From the results of this research can be concluded that the reaction mechanism occurs in theprocess is the reaction mechanism of cracking, the higher of electric voltage and the longer of reaction time leadto increasing of product yield. The more of mole ratio of methanol / oil and widening the gap between theelectrodes lead to decreased product yield. From this research, product yield maksimum is 89,8% in the variableof rasio mol metanol/palm oil 3:1, voltage 10 kV, electrode gap 1,5 cm, and reaction time 30 seconds.
PERMODELAN DAN OPTIMASI HIDROLISA PATI MENJADI GLUKOSA DENGAN METODE ARTIFICIAL NEURAL NETWORK - GENETIC ALGORITHM Istadi Istadi; Dian Rahmayanti
TEKNIK Vol 31, No 2 (2010)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (798.394 KB) | DOI: 10.14710/teknik.v31i2.1767

Abstract

Modeling and optimization methods are commonly used, still not able to model and optimize the complexchemical processes non-linear. Hybrid method of Artificial Neural Network-Genetic Algorithm (ANN-GA) isconsidered as an effective method for resolving these problems and obtain optimum conditions globally. Theaim of this study is to develop a modeling and optimization with hybrid ANN-GA methods, which applied inprocess of making glucose from starch hydrolysis. The ANN-GA stategy consists of two steps. In the first step,an ANN-based prosess model is developed. Therefore, the input at ANN model will be optimized using GAtechnique. The optimal values of starch concentration, enzyme concentration, temperature and time with ANNGAmethod were 7,13 % (w/v), 1,47 %(w/v), 40,53ºC, and 166,04 min respectively with predicted glucose yieldof 6,08 mg/mL. These result differed from the secondary data (Baskar et al., 2008) which were used RSM. Itwas because R2 values of ANN-GA method was 0,9755. While RSM method was only able to achieved value ofR2 for 0,842. Modeling and optimization with the GA-ANN can be developed and used to obtain the model instarch hydrolysis into glucose and the optimal operating conditions simultaneouosly.
Co-Authors Ardian Dwi Yudhistira Dian Rahmayanti J. P Sitompul Koswara Koswara Y. Bindar