A Conceptual Efficient Design Of Energy Recovery Systems Using A New Energy-area Key Parameter

Energy integration in petrochemical and refining industries is an effective concept to minimize dependence on heating and cooling utilities through networks of exchanger equipment. Pinch Analysis is very popular and successful technique to optimize heat recovery between heat sources and sinks. Yet, design of networks of exchangers is challenging and requires careful attention to energy consumption and exchanger areas. This work presents a graphical methodology to design exchanger networks taking into account both heat loads and transfer areas of exchanger units in one single information. A new parameter is introduced for design that is the ratio between the heat load and the exchanger area and is determined in kW/m2. It is defined as an energy-area parameter expressing how much heat the exchanger would transfer per every meter square of area. Such parameter will be valuable key in design to screen matches of exchangers providing that both the heat and area are considered. The higher the value of the parameter, the better the performance of the exchanger, i.e. maximum heat transfer rate for minimum exchanger area. The design methodology embedding the energy-area parameter guarantees HEN designs with energy targets and minimum areas. A case is studied for the production of 100,000 t/y of dimethyl ether. An optimum network is generated by applying the new parameter with less exchanger areas and hot utility of 25% and 30%, respectively compared with an automated design by Aspen Energy Analyzer®. Also, substantial savings of about 47% in the total cost of the network are earned

Mathematica as an Efficient Tool to Optimize the Kinetic Study of Ethyl Acetate Hydrolysis

Mathematica is a powerful program for computing both numeric and algebraic calculations as well as graphing two- and three-dimensional curves and surfaces. It is used increasingly in many fields of science now such as physics, engineering, chemistry and even biology because of the fast interaction of mathematics with almost the fields of science nowadays. We report here, optimizing the kinetic data for the hydrolysis of ethyl acetate through caustic soda via using Mathematica

Simulation And Optimization Of Waste Heat To Electricity Through Organic Rankine Cycles (ORCs): A Case Study In An Oil Refinery

Energy efficiency has become a global problem that is detrimental to the chemical industries technically, economically and to the environment. Organic Rankine Cycle (ORC) is a promising technology that can solve this problem by recovering heat from low-grade waste heat sources by using organic working fluids. The heat source for the ORC system used in this article is air leaving air coolers in an oil refinery with a temperature of 140o C. The heat exchanger data for this refinery was used in the simulation of a basic cycle and a regenerative cycle using ASPEN HYSYS V.10. These ORC systems were simulated using hydrocarbons, refrigerants, and alternative refrigerants as the working fluids to compare their performance at three different condensation temperatures which are 15o C, 35o C, and 50o C. The system was optimized using the HYSYS optimizer to reach the optimum conditions for each working fluid. Results of this study have proven that the alternative working fluids R1234ze (Z) and R1224yd (Z) perform very well when compared to hydrocarbon working fluids and outperform the regular refrigerants. For the basic cycle which yielded the optimum results, R1234ze (Z) produced 1258.90 kW of turbine work and has a thermal efficiency of 11.31%. Hence, they are promising working fluids and are highly recommended to be used in the future since they perform highly economically in addition to being environmentally friendly

Hydrothermal Synthesis Of Graphene Supported Pd/Fe 3 O 4 Nanoparticles As Efficient Magnetic Catalysts For Suzuki Cross – Coupling

This research reports a reproducible, reliable, and efficient method for preparing palladium nanoparticles dispersed on a composite of Fe3O4 and graphene as an active catalyst with high efficiency for being used in Suzuki cross – coupling reactions. Graphene supported Pd/Fe3O4 nanoparticles (Pd/Fe3O4 /G) exhibit a remarkable catalytic performance towards Suzuki coupling reactions. Moreover, the prepared catalyst recyclability was up to nine times without losing its high catalytic activity. The catalyst was prepared using hydrothermal synthesis; the prepared catalyst is magnetic in order to facilitate catalyst separation out of the reaction medium after reaction completion simply through using a strong magnet. This approach offers unique advantages including recyclability, mild reaction conditions, and reproducibility. Furthermore, the magnetic properties of the prepared catalyst made a huge enhancement to the ability to purify the reaction products from catalyst and other side products. The high catalytic performance and recyclability of the prepared catalyst are due to the strong interaction between the catalyst and the support. Moreover, the reduced GO nanosheets have defect sites acting as nucleation centers to anchor the Pd and Fe3O4 nanoparticles and hence minimize the harmful effect of potential agglomeration and subsequently the anticipated decrease in the catalyst catalytic activity as a direct impact for this unfavorable agglomeration

Better Heat And Power Integration Of An Existing Gas-oil Plant In Egypt Through Revamping The Design And Organic Rankine Cycle

Objective: The current study aims mainly to Maximize Condensate Recovery (NGLs), focusing on a gas processing train of Gas-Oil Separation Plant (GOSP) located in Egypt with a capacity of 4,230 kmole/h. Methods: The research study accounts for the constraint of Reid Vapor Pressure (RVP) specification, which makes the storage in floating roof tanks is of a great risk. The study proposes the installation of the cryogenic train that recovers condensates (C4+). This train comprises of compression unit, expansion unit, three-phase separators and a re-boiled absorber. The problem of RVP will no longer exist because of the re-boiled absorber achieving RVP according to export specifications (RVP below 82.74 kPa). Heat integration is applied over the whole process to minimize the reliability of the external utilities. Further, an Organic Rankine cycle (ORC) is introduced to the existing unit for more heat integration to develop useful work from process waste heat. Furthermore, both environmental emissions of CO2 and economic implications are investigated. Results: Energy integration played a vital role in decreasing the compressing power by about 31%, the cooling load by about 81%, and eliminating the heating load leading to zero CO2 emissions. Conclusion: The new energy-integrated retrofit scenarios exceed the recommended revamping schemes by previous works and base case in all aspects of condensate recovery, energy-saving, environmental concerning and economics

The Kinetic Study of DPT Using Mathematica as an Efficient Optimization Tool

Mathematica is a powerful program for computing both numeric and algebraic calculations as well as graphing two- and three-dimensional curves and surfaces. It is used increasingly in many fields of science now such as physics, engineering, chemistry and even biology because of the fast interaction of mathematics with almost the fields of science nowadays. Synthesis of Cyclotetramethylene Tetramine through the action of nitrating mixture formed of ammonium nitrate and fuming nitric acid on hexamine in presence of acetic acid, acetic anhydride and p-formaldehyde has been proven. The pathway is relatively long and Hexamine Dinitrate and Dinitro Pentamethylene Tetramine (DPT) are two of the main intermediate compounds. The former was prepared, purified, and then characterized. Conversion of this compound into the latter has been followed up experimentally. Herein, we report the Preparation of Dinitro Pentamethylene Tetramine (DPT) from Hexamine Dinitrate - as an alternative synthetic route - which is an important intermediate appears through preparation of DPT from Hexamine directly. DPT was prepared at different temperatures. The variation of some factors like: temperature and time has been investigated. The obtained results were reliable and consistent with the literature. The conversion of Hexamine Dinitrate to HMX as another synthetic route was not fully studied from the point of view of kinetics. In this paper, it is intended to study the effect of time and temperature on the conversion rate of hexamine dinitrate to DPT. This scientific approach is considered as a bridge through which we aim to initiate a complete kinetic study of an important intermediate in the synthesis route of one of the most powerful energetic materials. We report here, optimizing the kinetic data for the synthesis of DPT via using Mathematica

Graphical Revamping Of A Crude Distillation Unit Under Two Variable Operational Scenarios - Naphtha Stabilizer And Reformer Operated

Energy costs represent significant parts of the total operating costs of crude refining industries. Energy integration is a typical solution to reduce heating and cooling utilities in crude refining plants through maximizing the target temperature of crude oil streams before entering the furnace. Over the past few decades, a significant progress has been made in energy integration methods including Pinch technology and mathematical programming approaches. Example of these is a graphical technique which plots Thot versus Tcold for energy analysis and revamping studies. The current research employs the Thot - Tcold diagrams in an algorithm to retrofit an existing crude atmospheric distillation unit (CDU) located in north of Egypt (Suez region). This real CDU unit is operated under two different operational modes: (i) without naphtha stabilizer; the process reformer is in operation to reform all naphtha streams without stabilization, and (ii) with naphtha stabilizer; LPG is separated from naphtha stream. The performance of the current HEN is analyzed using the graphical axes of Thot - Tcold diagrams. The graphical method is used to identify exchangers across the Pinch and recognize the potential modifications to improve the energy performance and reduce fuel consumption. Implementing the graphical identified modifications on the existing plant resulted in: (1) stabilizer scenario; energy savings are achieved by 21.1% with additional capital investment of 0.81 MM$and annual energy savings of 0.82 M$, (2) reformer scenario; the energy savings are 0.42 MM$with capital investment of 0.33 M$

Graphical Analysis and Revamping of Crude Distillation Units under Variable Operational Scenarios

Energy Cost Represents a Significant Part of the Total Operating Costs of Many Processing Units. Crude Distillation is an Energy Intensive Process. Energy Integration is a Typical Solution to Reduce Heating and Cooling Utilities through Maximizing the Target Temperature of Crude Oil Streams Before Entering the Furnace. over the Past Few Decades, Significant Progress Has Been Made in Energy Integration Methods Including Pinch Technology and Mathematical Programming Approaches. Very Recently, Graphical Techniques Have Been Developed for Revamping Studies and Energy Analysis. Such Diagrams Are Valuable in Energy Targeting to Identity Energy Inefficiencies and Are Key to Potential Modifications for Maximum Energy Integration. the Current Research Applies the Recent Graphical Revamping Methodology on an Existing Crude Atmospheric Distillation Unit. the Unit is Located in North of Egypt (Suez Region) and is Operated under Two Different Operational Modes; (1) Without Naphtha Stabilizer; the Process Reformer is in Operation to Reform All Naphtha Streams Without Stabilization and (2) with Naphtha Stabilizer; LPG is Separated from Naphtha Stream. a Graphical-Based Revamping Methodology is Applied to Retrofit the Existing Preheat Train. the Revamping Procedure Starts by Simulating the Existing HEN Data, Followed by Validation Against the Real Data. the Current Performance of the HEN is Analyzed using the Graphical Axes of Thot-Tcold Diagrams. the Graphical Method is Then Used to Identify Exchangers Across the Pinch and Recognize the Potential Modifications to Improve the Energy Performance and Reduce Fuel Consumption. Implementing the Graphical Identified Modifications on the Plant Resulted in the Following Benefits: (1) When Stabilizer is in Operation, Energy Savings Are Achieved by 21.1% with Additional Capital Investment of 0.81 MM$and Annual Energy Savings of 0.82 MM$, with a Payback Period of One Year. (2) When Reformer is in Operation, the Energy Savings Are 0.42 MM$with Capital Investment of 0.33 MM$. the Methodology Results Provide a Flexibility in Refineries Operations

Retrofit design of heat-integrated crude oil distillation systems

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