eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
1
8
20160
Formation Kinetics of Structure H Gas Hydrate
Mohsen Vafaii Sefti
1
Behnaz Parvizi
behnazparvizi@yahoo.com
2
Farshad Varaminian
fvaraminian@semnan.ac.ir
3
Engineering Faculty, Tarbiat Modares University, Iran
School of Chemical, Gas and Petroleum Engineering, Semnan University, Iran
School of Chemical, Gas and Petroleum Engineering, Semnan University, Iran
This paper investigates the kinetics of structure H (sH) formation kinetics above and below the structure I (sI) formation equilibrium curve at temperatures of between 2Â°C and 6Â°C. Methane was used as a help gas and methylcyclohexane (MCH) was used as sH former. It was concluded that in the points above the sI formation equilibrium curve, at the first, the sI forms, and then converts to sH because of the low solubility of MCH in water. In the points under the sI equilibrium curve, at the first sH forms after a long induction time. The study also show the effect of the addition of hydroxymethylcellulose (in three concentrations of 0.05, 0.1 and 0.15 Wt%) on sH hydrate formation kinetics. With this additive, it was observed that the rate of sH formation increases.
http://gpj.ui.ac.ir/article_20160_a19a3727658465066539b0ccf77cf6a4.pdf
sH
sI
Formation Kinetics
Gas Hydrate
eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
9
18
20161
Selection of the Best Efficient Method for Natural Gas Storage at High Capacities Using TOPSIS Method
Alireza Sanaei
1
Seyed Hamidreza Yousefi
2
Ehsan Khamehchi
khamehchi@aut.ac.ir
3
School of petroleum and geological Engineering, University of Oklahoma, USA
Department of Petroleum Engineering, Amirkabir University of Technology, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, Iran
Nowadays one of the most important energy sources is natural gas. By depletion of oil reservoirs in the world, natural gasÂ will emerge as the future energy source for human life. One of the major concerns of gas suppliers is being able to supply this source of energy the entire year. This concern intensifies during more consuming seasons of the year when the demand for natural gas increases, resulting in a lot of problems such as pressure depletion in the pipelines. One of the most effective policies to prevent pressure depletion is gas storage in warm seasons of the year when public demand is low. In this paper three different methods of underground and surface gas storage at high capacities have been discussed which are as follows: depleted oil and gas reservoirs, liquefied gas storage, and gas hydrates storage. In this study, the NPV function for economical evaluation of these three natural gas storage methods was employed. Finally, after assessing the technical and economical aspects of these methods, the TOPSIS model was constructed and depleted oil and gas reservoirs storage selected as the best natural gas storage method at high capacities.
http://gpj.ui.ac.ir/article_20161_e6cc8e5a259d810d54bb012071e8d24b.pdf
Natural Gas Storage
Net Present Value
TOPSIS Method
eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
19
40
20162
The Design of the Best Heat Integrated Separation Systems Using Harmony Search Algorithm
Gholam Reza Salehi
rezasalehi20@gmail.com
1
Majid Amidpour
amidpour@gmail.com
2
Bahram Ghorbani
bahram330ghorbani@gmail.com
3
Kazem Hasanzadeh Lashkajani
bah_ghorbani@yahoo.com
4
Islamic Azad University Branch of Nowshahr, Iran
Energy System Engineering Department, K.N.Toosi University of Technology, Iran
Energy System Engineering Department, K.N.Toosi University of Technology, Iran
Energy System Engineering Department, K.N.Toosi University of Technology, Iran
The synthesis of heat integrated multi-component distillation systems is complex due to its huge search space for structural combination and optimization computation. To provide a systematic approach and tools for the synthesis design of distillation systems, a new method for modeling heat integrated columns is presented, and the operating cost objective function is minimized by improved harmony search algorithm (IHS). This paper studies a quick method for the synthesis of heat integrated distillation column sequences and IHS -based optimization strategy for the optimization of separation sequences with their heat integration.Â
http://gpj.ui.ac.ir/article_20162_439ea12ae7b36ea933e2dc029c2115fe.pdf
Distillation Sequence
Heat Integration
optimization
IHSA
eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
41
50
20158
Predicting the Hydrate Formation Temperature by a New Correlation and Neural Network
Hamidreza Yousefi
1
Ebrahim Shamohammadi
e.shamohammadi@gmail.com
2
Ehsan Khamehchi
khamehchi@aut.ac.ir
3
Department of Petroleum Engineering, Amirkabir University of Technology, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, Iran
Gas hydrates are a costly problem when they plug oil and gas pipelines. The best way to determine the HFT and pressure is to measure these conditions experimentally for every gas system. Since this is not practical in terms of time and money, correlations are the other alternative tools. There are a small number of correlations for specific gravity method to predict the hydrate formation. As the hydrate formation temperature is a function of pressure and gas gravity, an empirical correlation is presented for predicting the hydrate formation temperature. In order to obtain a new proposed correlation, 356 experimental data points have been collected from gas-gravity curves. This correlation is programmed and assessed with respect to its capabilities to match experimental data published in the literature under varying system conditions (i.e. temperature, pressure, and composition).The SPSS software has been employed for statistical analysis of the data. In order to establish a method to predict the hydrate formation temperature, a new neural network has also been developed with the BP(Back Propagation) method. This neural network model enables the user to accurately predict hydrate formation conditions for a given gas mixture, without having to do costly experimental measurements.
http://gpj.ui.ac.ir/article_20158_b01023a76a34375e55ef613e5f004495.pdf
Hydrate Formation Temperature
AUT Correlation
Artificial neural network
eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
51
68
20163
The Design and Optimization of Distillation Column with Heat and Power Integrated Systems
Gholam Reza Salehi
rezasalehi20@gmail.com
1
Bahram Ghorbani
bahramghorbani20@gmail.com
2
Kazem Hasanzadeh Lashkajani
bah_ghorbani@yahoo.com
3
Majid Amidpour
amidpour@gmail.com
4
3Islamic Azad University Branch of Nowshahr, Iran
Bahram Ghorbani, PhD candidate
Mechanical Engineering Faculty, Energy Conversion Group
KNToosi University of technology, Tehran, Iran,
Bahram330ghorbani@gmail.com
Energy System Engineering Department, K.N.Toosi University of Technology, Iran
Energy System Engineering Department, K.N.Toosi University of Technology, Iran
Based on two integration steps, an optimization framework is proposed in this work for the synthesis and design of complex distillation sequence. The first step is to employ heat integration in sequence and reduce the heat consumption and total annual cost of the process. The second one is to increase the exergetic efficiency of sequence by generating power in implemented expanders in sequence. The profit of power generation directly affects the operating cost of the process and decreases the total annual cost. In each step, the target is to minimize the objective function of total annual cost. A simulator is used to simulate the equipmentâs specification and formulate the objective function of cost. Results from employing these two integration steps for the considered case study show the advantages of such a complex distillation sequence with heat integration and power generation. The results represent a very high improvement for the sequence Indirect since the properties of the intake flow to the process are in a way that in this sequence not only do we have a high freedom for carrying out heat integration, but a large amount of power is also produced between the columns due to having high flow rate flows between the columns
http://gpj.ui.ac.ir/article_20163_6587325a8883837189d6101ef0033303.pdf
Distillation
Sequence
Modeling
Integration
optimization
Expander
eng
University of Isfahan
Gas Processing
2322-3251
2345-4172
2013-01-01
1
1
70
87
20159
The Indication of Two-Phase Flow Pattern and Slug Characteristics in a Pipeline Using CFD Method
Elahe Bahramifar
1
Rahbar Rahimi
rahimi@hamoon.usb.ac.ir
2
Maryam Mazarei Sotoodeh
3
Multiphase flows are commonly encountered in oil and gas industries. The transport of multiphase flow causes the formation of slug, the increase of pressure drop and the possibility of phase changes therefore, a set of simulation runs was performed to predict flow regimes in a horizontal pipeline, and the results were compared with the Baker chart. The effects of small downward inclinations of pipelines on the formation of slugs were also considered.Volume of Fluid model (VOF) has been used to predict the flow regimes in a horizontal pipeline within an 8-cm diameter and 7-m length pipe. In order to identify the critical parameters of slug flow (mean slug frequency, slug translational velocity, hold up and pressure drop), the simulations were carried out in a 7.63-cm diameter and 5-m length pipe mounted with three different inclination angles of 0 ,-0.5 and -0.8 . A good agreement between CFD model and experimental data has shown the advantage ofÂ Â VOF model for studying two-phase flows.
http://gpj.ui.ac.ir/article_20159_e0cd5b37c713a41c2751bb1b193b8776.pdf
Inclination
Two-Phase Flow
Slug Flow
CFD
VOF
Baker Chart
Two
Phase Flow