Papers by M. Hassan Panjeshahi
Applied Thermal Engineering, Aug 1, 2016
Feasibility of turbo expander integration with an industrial plant was studied. Combined pinch-ex... more Feasibility of turbo expander integration with an industrial plant was studied. Combined pinch-exergy analysis was used to achieve optimum performance of process. Generation of power led to profitability of gas turbine integrated plant.
Journal of Power Sources, Oct 1, 2015
A numerical model is introduced and verified for simulation of a six-cell VRFB. Effects of electr... more A numerical model is introduced and verified for simulation of a six-cell VRFB. Effects of electrolyte flow rate on VRFB performance is numerically investigated. Energy and exergy efficiencies at different operating condition are analyzed. The strategy of electrolyte flow rate is discussed using thermodynamic efficiencies.
International Journal of Hydrogen Energy, Mar 1, 2013
Extensive use of hydrogen in refineries and petrochemical plants is an incentive for designing in... more Extensive use of hydrogen in refineries and petrochemical plants is an incentive for designing integrated hydrogen networks to utilize hydrogen more efficiently. On the other hand, hydrogen, as an important byproduct, is not properly used in some petrochemical complexes and mostly sent to the fuel system. Few works have been reported in literature for improving hydrogen network in petrochemical complexes. In this paper, however, a modified automated targeting approach has been developed and applied to petrochemical plants for estimating fresh hydrogen target. Furthermore, this paper is aimed to develop a superstructure based optimization framework to consider hydrogen plant as part of the whole network. Also, four industrial cases are studied to demonstrate the importance of hydrogen management in petrochemical complexes and proving the applicability of the new method.
Chemical engineering research & design, Aug 1, 2013
Concerns about global warming have led governments to regulate CO 2 emissions, including through ... more Concerns about global warming have led governments to regulate CO 2 emissions, including through emissions caps, trading and penalties, thus creating economic incentives to reduce CO 2 emissions. This paper presents a mathematical model based on a MINLP formulation to address the problem of CO 2 emissions from large-scale sites in the process industries. The proposed approach considers the interactions between process units, associated heat exchanger networks and the site utility system. The CO 2 emissions reduction strategies considered include retrofit of heat exchanger networks (HENs), operational optimization of the utility system and fuel switching. The mathematical model captures interactions between the HEN and the utility system; the optimization explores these interactions systematically within a superstructure of CO 2 reduction options. The optimization objective is to determine suitable CO 2 -mitigation options for a given emissions reduction target and available capital for investment, taking carbon trading issues into account. The proposed approach is applied to a published industrial case study; the results demonstrate the applicability of the approach to finding cost-effective solutions for CO 2 emissions reduction. Results show that the best solution CO 2 emissions reduction is affected by carbon trading. Therefore, opportunities to sell CO 2 allowances, if practically achievable, play an important role in the process economics.
Elsevier eBooks, 2012
ABSTRACT Environmental legislation pressure on the energy sector to control greenhouse gas emissi... more ABSTRACT Environmental legislation pressure on the energy sector to control greenhouse gas emissions is increasing. Regulations typically impose a limit on carbon emissions released by industries and set an emissions reduction target. If emissions reduction targets are not met, economic penalties are applied. Over the last decade, worldwide commitments to meet CO2 emissions reduction targets have challenged the process industries to reduce CO2 emissions. A key challenge for recovering carbon dioxide from industrial process sites is the low concentration of CO2 in the flue gas. The Integrated Gasification Combined Cycle (IGCC) can provide a relatively pure CO2 exhaust gas that lends itself to sequestration. In this paper, integration of a site utility system with a gasification cycle is introduced as an option to provide a compressed CO2-rich stream from a process site. Optimization applies the results of screening studies based on rigorous simulation of the IGCC. The IGCC design parameters (including oxygen consumption, compressor pressure ratio and turbine pressure ratio) are optimized for two reference cases: maximum heat and maximum power generation. Interactions between the IGCC and CO2 emissions compression train are explored for maximum heat and maximum power generation; further work will address economic and operational aspects of integrating the utility system with an IGCC.
... Lena Ahmadi is with the Department of Energy Engineering, KN Toosi University of Technology, ... more ... Lena Ahmadi is with the Department of Energy Engineering, KN Toosi University of Technology, Tehran, 1999143344, Iran (email: [email protected]). expensive and are not always effective. ... Appl. Therm. Eng. vol. 21, pp.899-915, 2001. [2] SK Tyagi, Shengwei Wang, SR ...
Chemical engineering transactions, Oct 30, 2019
This paper presents new graphical tools, which can quickly identify all thermal exergy losses occ... more This paper presents new graphical tools, which can quickly identify all thermal exergy losses occurring in process design particularly in condensers/evaporators of low-temperature processes. Although the Omega -H diagram is a powerful tool for getting insights about exergy loss in a heat exchanger network (HEN), the calculation of the enclosed area is not straightforward due to non-linearity of the curves. The Omega Composite Curves (OCCs) and Omega Grand Composite Curve (OGCC) developed in this research are new graphical tools that can be applied to any process, including sub-ambient processes. These curves are linear, and all enclosed areas have a rectangular shape. So, all thermal exergy losses can readily be calculated and also necessary modifications to enhance the efficiency of refrigeration systems, either in new design or retrofit study can graphically be suggested. To demonstrate the capability of the new graphical tools, two ammonia refrigeration cycles (one single-stage and one three-stage) have been designed to fulfil the cooling demand of a sub-ambient process and achieve minimum shaft work requirements. The exergy loss associated with each unit in the refrigeration cycle is directly calculated from the OGCC diagram. This is a convenient tool for calculation of exergy losses and can be used to compute the enclosed areas between the OGCC and the condenser/evaporator horizontal lines. The enclosed areas show that exergy loss for 3-stage compression is much less than that in the 1-stage cycle. Also, for the throttling valve, the exergy loss in the 3-stage refrigeration is considerably less than that in the 1-stage cycle. The new linear curves can easily be plotted and implemented to show the share of inefficiencies occurring in different unit operations.
Chemical engineering transactions, Mar 20, 2017
Benchmarking of different process industries, such as petrochemical processes, with respect to en... more Benchmarking of different process industries, such as petrochemical processes, with respect to energy consumption and CO2 emission, is a fundamental measure while implementing a comprehensive energy plan at the national level. Olefin Plant is one of the process industries that is highly energy intensive and needs to be addressed when looking at petrochemical complexes. In this research, olefin cold-end, which requires heat removal from the process via refrigeration at very low temperatures, has been studied. In sub-ambient processes, shaft work requirement is a dominant factor that causes very high energy cost. A conceptual mathematical model has been developed to facilitate energy benchmarking in olefin cold-end processes. A conceptual model using Pinch analysis is developed to predict energy consumption in refrigeration cycles. To develop the model, the cold-end from five Iranian olefin plants were studied and the effect of different factors such as technology, capacity, feedstock and product types were investigated. The gap between the current level of energy consumption and best practice technology using Pinch analysis was determined. The comparison showed an average potential of 17.7 % reduction in shaft work requirement. Having developed the aforementioned model, there is no need to undertake a full retrofit study for olefin cold-end processes anymore because the model can easily be applied to similar processes and the scope for improvement can be identified. Both time and money associated with extra engineering work can be saved. Application of this model to all olefin's cold-end processes in Iran showed that there would be 65,838 kW/h potential for energy consumption reduction, which is equivalent to about 382,519 t of CO2 emissions.
Zenodo (CERN European Organization for Nuclear Research), May 23, 2012
In this study the integration of an absorption heat pump (AHP) with the concentration section of ... more In this study the integration of an absorption heat pump (AHP) with the concentration section of an industrial pulp and paper process is investigated using pinch technology. The optimum design of the proposed water-lithium bromide AHP is then achieved by minimizing the total annual cost. A comprehensive optimization is carried out by relaxation of all stream pressure drops as well as heat exchanger areas involving in AHP structure. It is shown that by applying genetic algorithm optimizer, the total annual cost of the proposed AHP is decreased by 18% compared to one resulted from simulation.
International Journal of Exergy, 2013
ABSTRACT This paper presented a new approach to estimate the degradation of environmental resourc... more ABSTRACT This paper presented a new approach to estimate the degradation of environmental resources in a Wastewater Treatment Plant (WWTP) using exergy analysis. In first part, a method was described to calculate various quantities of the wastewater exergy. Furthermore, units were analysed to determine the most defective unit. In second part, a case study was analysed based on the environmental exergy concepts. Two environmental indexes include Environmental Exergy Efficiency (EEE) and the Total Pollution Rate (TPR) were considered for quantification of environmental impacts. In third part, the primary clarifier was determined as the most defective unit. At least, the optimised network was presented to performance improvement and environmental impacts reducing. EEE and TPR indexes were changed from 6.14 and 0.14 to 1.79 and 0.36, respectively. In addition, the results of this paper showed that exergy analysis can be used as a tool for quantification and optimisation of WWTP.
World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, Aug 1, 2014
A techno-economic evaluation for efficient use of energy in a large scale industrial plant of met... more A techno-economic evaluation for efficient use of energy in a large scale industrial plant of methanol is carried out. This assessment is based on integration of a gas turbine with an existing plant of methanol in which the outlet gas products of exothermic reactor is expanded to power generation. Also, it is decided that methanol production rate is constant through addition of power generation system to the existing methanol plant. Having incorporated a gas turbine with the existing plant, the economic results showed total investment of MUSD 16.9, energy saving of 3.6 MUSD/yr with payback period of approximately 4.7 years.
World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, Aug 1, 2014
Gas flaring is one of the most GHG emitting sources in the oil and gas industries. It is also a m... more Gas flaring is one of the most GHG emitting sources in the oil and gas industries. It is also a major way for wasting such an energy that could be better utilized and even generates revenue. Minimize flaring is an effective approach for reducing GHG emissions and also conserving energy in flaring systems. Integrating waste and flared gases into the fuel gas networks (FGN) of refineries is an efficient tool. A fuel gas network collects fuel gases from various source streams and mixes them in an optimal manner, and supplies them to different fuel sinks such as furnaces, boilers, turbines, etc. In this article we use fuel gas network model proposed by Hasan et al. as a base model and modify some of its features and add constraints on emission pollution by gas flaring to reduce GHG emissions as possible. Results for a refinery case study showed that integration of flare gas stream with waste and natural gas streams to construct an optimal FGN can significantly reduce total annualized cost and flaring emissions.
Chemical engineering research & design, Feb 1, 2015
ABSTRACT An integrated gasification combined cycle (IGCC) may be used to generate steam and power... more ABSTRACT An integrated gasification combined cycle (IGCC) may be used to generate steam and power while providing a capture-ready CO2 stream. This work addresses techno-economic optimization of an IGCC integrated with the utility system for a process site, with the aim of cost-effective reduction of CO2 emissions. The IGCC can generate power and produce steam in parallel with the site utility system; integration of the IGCC into the site utility system means that the heat recovered from the IGCC is fed to the utility system, where it is used to generate steam to meet site heat and power demand. A relatively rigorous simulation model of the IGCC is applied to explore steam and power generation opportunities for various fuel flow rates. A simple, linear model is regressed from these simulation results to correlate fuel consumption and steam and power generation by the IGCC. The simple model is integrated into a model for simulation and optimization of the site utility system; the operating conditions of the overall system (IGCC and site utility system) can then be optimized to minimize the operating cost, taking into account the capacity and efficiency of equipment such as boilers and steam turbines, the cost of fuel, the cost or value of power, and costs associated with CO2 emissions. The proposed optimization method is illustrated by application to an industrially-relevant case study. The results indicate that integrating an IGCC with a site utility system can provide an effective route for cogeneration of heat and power with low carbon emissions and low operating costs, although the economic benefits are sensitive to fuel, power and emissions-related costs.
World Academy of Science, Engineering and Technology, International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, Jun 6, 2016
Abstract Utilization of fossil fuel, as one of the major contributors in CO 2 emission production... more Abstract Utilization of fossil fuel, as one of the major contributors in CO 2 emission production, provides driving force behind global warming. Increasing energy efficiency through energy retrofit of process plants can reduce fuel requirement and hence reduce ...
Petroleum Science and Technology, Jun 22, 2019
ABSTRACT There is a wide range of resources for CO2 emissions. The net amount of CO2 emissions in... more ABSTRACT There is a wide range of resources for CO2 emissions. The net amount of CO2 emissions in the cement industry due to the consumption of fossil fuels and the chemical processes of cement production under heating raw materials is reported to be in the range of 15–25%; this industry, among all the industries and after the power plants and refineries, is the largest CO2 gas producer throughout the world. Using CO2 capture and storage (CCS), it can reduce greenhouse gas emissions in a short time. In this study, the technical feasibility study of recycling CO2 in Abyek Cement Company, with a cement production capacity of about 12,500 tons per day in two production lines, has been studied as one of the largest cement industries throughout the world. Fuel oil (Mazut) is used as the primary fuel for furnaces in this industry. Affected by combustion, the emissions emitted from the five-stage preheater contain 5/24% vol% of CO2, 7.6% H2O, 4.8% vol% of O2, and 63.1% N2.
Energy, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ChemistrySelect, Jul 9, 2020
The novel NiAl 2 O 4 spinel was used as support to synthesis cobalt catalysts and investigated fo... more The novel NiAl 2 O 4 spinel was used as support to synthesis cobalt catalysts and investigated for Fischer-Tropsch synthesis. The physicochemical properties of the synthesized catalysts (Co/NiAl 2 O 4 , Co/Rh/NiAl 2 O 4 , Co/Ru/NiAl 2 O 4 and Co/γ-Al 2 O 3 ) were characterized by XRD, BET, ICP, SEM, FESEM, HRTEM, TPR and TGA analysis before reaction. It was shown the use of novel NiAl 2 O 4 support that was prepared by a modified sol-gel process had a good dispersion. Besides that, Nickel aluminate decreased the interaction of Co and support and resulting in a significant increase in the reduction degree and the catalytic activity. The catalyst of 15Co/0.5Rh/NiAl 2 O 4 shows the highest catalytic activity. It is worth noting that the NiAl 2 O 4 support decreased the CH 4 selectivity but enhanced the C 5 + selectivity and catalytic stability.
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Papers by M. Hassan Panjeshahi