Saudi Aramco Journal of Technology Winter 2004 SaudiAramco Technology THE ROLE OF GEOMECHANICAL EARTH MODELING IN THE UNCONSOLIDATED PRE-KHUFF FIELD COMPLETION DESIGN see page 2 OPTIMIZATION OF PROCESS TOPOLOGY USING PINCH ANALYSIS see page 10 The Mature Mechanical Earth Model – Young’s modulus volume compared to well control. Rock properties taken from 3D seismic volume with over 600,000 psuedo well locations. The Saudi Aramco Journal of Technology A quarterly publication from the Saudi Arabian Oil Company
Transcript
Saud
i Aram
co Jo
urn
al of Tech
no
log
y Win
ter 2004
SaudiAramcoTechnologyTHE ROLE OF GEOMECHANICAL EARTHMODELING IN THE UNCONSOLIDATEDPRE-KHUFF FIELD COMPLETIONDESIGN see page 2
OPTIMIZATION OF PROCESSTOPOLOGY USING PINCHANALYSIS see page 10
The Mature Mechanical Earth Model – Young’s modulus volume
compared to well control. Rock properties taken from 3D seismic
volume with over 600,000 psuedo well locations.
The Saudi Aramco Journal of Technology A quarterly publication from the Saudi Arabian Oil Company
SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004 1
The Saudi Aramco Journal of Technology is published quarterly by the Saudi Arabian Oil Company, Dhahran, SaudiArabia, to provide the company’s scientific and engineering communities a forum for the exchange of ideasthrough the presentation of technical information aimed at advancing knowledge in the hydrocarbon industry.
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EDITORThe Saudi Aramco Journal of Technology2239 East Administration BuildingDhahran 31311, Saudi ArabiaTel: +966/3-873-2699E-mail: [email protected]
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Abdallah S. Jum‘ahPresident & CEO, Saudi Aramco
Mustafa A. JalaliVice President, Saudi Aramco Affairs
The Saudi Aramco Journal of Technology gratefully acknowledges the assistance, contributionand cooperation of numerous operating organizations throughout the company.
Kumana heads Saudi Aramco’s Energy ConservationGroup in the Energy Systems Unit of the ConsultingServices Department (CSD) in Dhahran. He holds a mas-ter’s degree in chemical engineering from the University ofCincinnati in Ohio, and has more than 30 years of expe-rience in process design and energy optimization. Kumanahas provided consulting services to major internationalcorporations including Shell, BP Amoco, Pemex, Dupont,Monsanto (Solutia), SASOL, Union Carbide, GeneralMotors, Enron and Mitsubishi Heavy Industries, as well asthe U.S. Department of Energy and the U.S. ElectricPower Research Institute. He has authored or co-authoredmore than 60 technical papers and book chapters.
Qahtani is in Saudi Aramco’s ProfessionalDevelopment Program with the Energy Systems Unit ofthe CSD. He is on field deployment at the Berri GasPlant. He has a BS degree in mechanical engineering fromthe University of Toledo in Ohio and has been with SaudiAramco for two years.
ABSTRACT
Optimization of manufacturing processes is a two-step activity. In the first step, onemust create the right process structure, or topology. In the second, one must followup by mathematically optimizing the numerical values of the important processparameters. Conventional mathematics is not suitable for qualitative decisions suchas those required for optimizing the topology of a chemical process. Attempts toconduct a parametric optimization based on “superstructures” have been successfulonly for small academic problems, not for large real problems. Over the past 25years, much better success has been obtained using recently-developed heuristic opti-mization techniques collectively known variously as “process integration,” “pinchanalysis” and “pinch technology.” The basic concepts and design rules of pinchanalysis are reviewed, and applications to important industrial problems are out-
Jimmy D. Kumana
Ali H. Al-Qahtani
lined, including: heat exchanger networks; combined heatand power systems; emissions optimization of combustiongases; cryogenic processes; chemical reaction systems,including catalysis; distillation column sequencing; distilla-tion column design for energy efficiency; batch crystalliza-tion; production capacity debottlenecking; water conserva-tion; distributed wastewater treatment facilities; refineryhydrogen management; and manufacturing supply chainmanagement. Some of the applications are mature. Othersare still in the R&D stage. Pinch analysis is presented as ageneral-purpose optimization tool, with applications limitedonly by the user’s imagination and ingenuity (Kumana andAl-Qahtani 2003). The emphasis is on finding the optimumprocess configuration (topology) using simple heuristic rulesrather than numerically optimizing parametric values.
INTRODUCTION
In the early 1980s, against a background of the so-called“energy crisis,” pinch technology emerged as a tool for thedesign of heat exchange networks. Its key feature was togive the engineer simple concepts to use interactively,enabling him to stay in control. Applying pinch analysis (asit is now called), the engineer could calculate the “target”energy requirement for any process and produce thermallyefficient and industrially acceptable designs which tookaccount of operability, plant layout, safety, startup, etc.
The basic concept is simple: the performance of any sys-tem is always limited by a single constraint – the pinch –just as the strength of a chain is determined by its weakestlink. If one needs a stronger chain, pinch analysis teachesthat the most cost-effective strategy is not to replace thechain with a new one, but to increase the strength of theexisting chain by selectively replacing the weakest link(s).
Pinch analysis achieved almost instant acceptance as asuperior approach to the design of optimum heat exchangernetworks (HENs), with proper account being taken of capi-tal costs and payback requirements. Typical fuel savingswere 20% or more, compared to the existing or previousbest design. In the next major advance, pinch analysis wasextended to the analysis of on-site utilities, such as boilers,turbines, heat pumps and refrigeration systems, and tech-niques were developed for optimum design of combinedheat and power (CHP) systems.
During the last decade, pinch analysis has evolved fromthis specialized tool for energy efficiency improvement intoa broad-based methodology for reducing capital costs, mini-mizing environmental pollution (NOx, SOx, VOC andwastewater), freshwater conservation, wastewater treatmentsystem design, batch process scheduling, capacity debottle-necking in both processes and utilities and site developmentplanning. The most recent applications have been in the
management of chemical species such as H2 and S in oilrefineries and the optimum combination of reactors andseparators. (Kumana 2001); (Smith 1995); (Linnhoff et al.1994); (Shenoy 1995); (Anon 1991); (EPRI publication no.BR-102466 1994); (Morgan 1992); and (Linnhoff 1994).
PINCH APPROACH
The general pinch approach is shown in fig. 1. The complexmulti-dimensional problem is first transposed into the pinchformat, which plots simplified “composite curves” ofresource (energy, water, etc.) demand and availability. Thentargets are set, and a broad set of pinch design rules areused to create a design that approaches the targets as close-ly as economically and practically possible. Working in thistransposed environment gives the engineer a simple visuali-zation of even the most complex problems and enablesquick assessment of alternatives, including outline econom-ics. Constraints can easily be considered and either over-come or accepted. Finally, the pinch environment is trans-posed back to process flow diagram (PFD) form, and theconventional steps of simulation, feasibility checking anddetailed design are completed.
This paper provides a general overview of nine majorapplications of pinch analysis:
• Thermal Energy Efficiency and Design of HeatExchanger Networks.
• Power Conservation and Recovery.• Total Site Energy Analysis.• Water Pinch and Distributed Effluent Treatment.• Integrated Process Debottlenecking.• Batch Process Optimization.• Oil Refinery Hydrogen and Sulfur Optimization.• Complex Distillation Systems.• Combined Reaction/Separation Systems.
Thermal Energy Efficiency and Design
of Heat Exchanger Networks
All chemical manufacturing processes require energy in theform of heat and power. Power is consumed both for shaftwork (to drive industrial machinery) and for process cooling.The individual process heating duties can be combined into asingle “cold composite curve” drawn on a temperature-enthalpy (T-H) diagram; it represents the enthalpy demandprofile of the process. Similarly, all the cooling duties can becombined into a single “hot composite curve,” which repre-sents the enthalpy availability profile of the process.
When both curves are plotted on the same T-H diagram,as in fig. 2, they show the opportunity for heat recovery aswell as the minimum net heating and cooling requirements.The point of closest approach, where available temperature
14 SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004
driving forces between hot and cold streams are at a mini-mum, is called the process pinch. It separates the overallprocess into two distinct thermal domains:
• A net heat sink above the cold pinch temperature,meaning that hot utility must be supplied.
• A net heat source below the hot pinch temperature,meaning that cooling must be provided.
The temperature difference between hot and cold streamsat the pinch is called the minimum approach temperature(MAT). For each value of MAT, there are correspondingvalues of minimum heating and cooling requirements(Qh)min and (Qc)min. These are the energy targets.
In order to achieve the targets, the HEN design must sat-isfy three conditions:
• No hot utilities are used below the pinch temperature.• No cold utilities are used above the pinch temperature.• No heat is transfered from hot streams above the pinch
to cold streams below the pinch.From these fundamental rules, useful design guidelines
and algorithms to optimize the HEN have been derived andcodified in the literature.
Power Conservation and Recovery
Energy has two primary manifestations – heat and power.Process integration concepts for heat recovery are well-established, but the techniques for power conservation andrecovery are relatively new. How does one recover power?This is done indirectly, through expansion of a high-pres-sure gas or through vapor through a turbine. In manychemical plants, high-pressure gases are let down throughan expansion valve, which wastes the potential energy inthe fluid. The high-pressure gas/vapor should instead beexpanded through a turbine that drives a pump, compressoror electric generator. By preheating the inlet gas against aprocess heat source, as in fig. 3, we can extract more power.Depending on process temperatures, the outlet gas couldalso be used for sub-ambient process cooling duty, in whichcase we may want to cool, rather than heat, the turbineinlet gas.
Power conservation is accomplished in many ways, butthere are three main strategies – reduce the flow, reduce thepressure drop and reduce the inlet temperature of thegas/vapor to a compressor – all of which could impact theprocess heat and material balance, which means that theheat exchanger network has to be modified as well.
Recent results (Kumana 2000) and (KumanaUnpublished results) have shown that when process modifi-cations for power conservation are followed up with ther-mal pinch analysis, total energy cost savings can be spectac-ular, ranging from 30 to 40%.
Total Site Energy Analysis
In total site energy analysis, the objective is to optimize theenergy interactions between multiple process units at a site.The residual heating and cooling duties (after heat recovery)are extracted from the “grand composite curves” of individ-ual process units and combined together in a total site pro-
SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004 15
Fig. 1. General pinch approach.
Problem
Solution & Feasibility
TransposeBack to PDF
Final DesignProcess
Design With Pinch Rules
The Pinch Approach-Rapid Screening
Iteration & Design
Transpose ToStream Problem
Composite Curves& Pinch
Targets
Data
Information
Fig. 2. Composite curves.
Hot Target
Cold Target
Region ofHeat Transfer
PINCH
Enthalpy
Tem
per
atu
re
Fig. 3. Turbo-expander integrated with HEN.
PowerTurbo-Expander
hot processstream
90 C°30 C°
0 C°to process
file, which gives a graphical representation of the total sitecombined heat and power (CHP) system, as in fig. 4. Thisconstruction enables the experienced engineer to understandthe integration possibilities between processes through utili-ties, appropriate steam levels and loads, cooling water duty,refrigeration levels and duties, optimum cogeneration strate-gy, fuel use, etc. There is usually a large potential forimprovement in overall site efficiency through inter-unitintegration via utilities, typically 10 to 20% at a two-yearpayback (Rudman 1995).
The economics of existing and proposed CHP configura-tions are then modeled by simulation, e.g., using an elec-tronic spreadsheet to confirm the steam/power balance andto calculate costs. The model calculates the true marginalcosts of steam consumption and power generation and is avery useful tool for evaluating energy conservation projectsin the global context. The simulation model is also usefulfor “what-if” analyses of alternative scenarios, such as dif-ferent production rates, different operating strategies, differ-ent fuel and electric supply contracts, etc. (Nath et al.1992).
Water Pinch and Distributed Effluent Treatment
Each water-related process operation has input and outputwater streams, and a set of composite curves for water sinks
(influent streams) and water sources (effluent streams) canbe constructed. Fig. 5 shows such a water-pinch construc-tion, which graphically depicts the water sources and sinksin a process, on purity versus flow axes. The “step” curvesare positioned relative to each other to be as close togetheras possible along the x axis without intersecting. The pointat which they touch is the pinch. The area of overlap (shad-ed) shows the scope for water reuse. As with energy pinch,rigorous design rules must be followed to evolve the opti-mum water reuse and “distributed effluent treatment”design.
Although the targeting concept is simple, optimizing awater network involving reuse, recycling and treatmentoptions with multiple contaminants can become very com-plex, because each contaminant results in its own unique setof source-sink curves and design solutions. The trick is toconsolidate all these disparate designs into a common onethat works for all contaminants. This is done using mathe-matical programming techniques and software. The waterpinch approach uses mathematical tools for optimization,and composite curves for graphical visualization and inter-preting the results (Rossiter (ed), Kumana et al. 1995); (El-Halwagi 1997); (Dhole et al. 1996); (Buehner and Kumana1996); (Kumana 1996); and (EPRI publ no. TA-1144531999).
16 SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004
Fig. 4. Total site profile.
Heat Flow
™PocketsºProcess to Process
Heat Transfer
Heat Flow
Heat Flow
Process A
Processes Processes
Heat Sources Heat Sinks
Process B
T O T A L S I T E P R O F I L E S
In arid parts of the world, such as Saudi Arabia, waterpinch becomes a crucial technology to conserve water,which is a scarce and expensive commodity costing up to $15/Kgal. The World Water Forum held in Japan inMarch 2003 highlighted the fact that fresh water availability is likely to reach crisis proportions on a world-wide scale within the next generation (www.world-waterforum.org). Water pinch, when properly applied, canhelp alleviate this situation.
Integrated Process Debottlenecking
Expanding production of existing process units will eventu-ally lead to capacity bottlenecks. The capacity pinch mayoccur in the piping system, in a distillation column, in theheat recovery network or in the utility system (e.g., firedfurnace, boiler, cooling tower, wastewater treatment).Traditionally, independent teams are set up to re-design thevarious parts of a process such as columns, heaters, con-densers, etc., to achieve the desired throughput. This oftenresults in missed opportunities to exploit differences in“capital efficiency” among different areas of the plant.Pinch analysis provides an integrated design approach inwhich cost-benefit trade-offs can be intelligently and easilymade across design disciplines and plant areas.
The tools include combined hydraulic/thermodynamicanalysis, column targeting and pressure drop vs. heat recov-ery network design (Karp et al. 1989). Examples include(Kumana, J.D., Unpublished results):
• Eight percent de-bottlenecking of column capacityachieved at much lower cost by adding a side con-denser, versus 5% capacity increase by conventionalretraying.
• Using extra heat exchange area and parallel trains toovercome both pump and furnace bottlenecks.
Although pinch techniques were originally developed prima-rily for continuous processes, excellent results have beenobtained for batch processes as well (Obeng and Ashton1988). Batch processes are usually constrained by a combi-nation of the following:
• Material flow (e.g., waiting for the next charge).• Heat flow (e.g., waiting to reach temperature).• Equipment capacity. • Labor utilization.• Environmental considerations.These factors are typically interlinked, with heat flow
and time playing dominant roles. Traditional schedulingtechniques, such as time-event charts and CPM/PERT, havebeen combined with pinch concepts into a systematicapproach for optimizing batch process schedules. Theseinclude energy pinch curves, cascade analysis and batch util-ity curves. The usual goal for batch plants is capacity debot-tlenecking. By reducing overall cycle time between the startof consecutive batches, capacity increases of up to 45 per-cent have been obtained with minimal capital investment(Kumana Unpublished results).
Oil Refinery Hydrogen Management
The trend in the oil refining industry, worldwide, is towardsthe use of heavier and more sour crude oils as feedstock anda lower demand for fuel oil. Coupled with lower sulfur andaromatics specifications for gasoline, refiners are facing aneed for dramatic increases in their hydro-treating capacity.Optimizing the recovery, distribution and utilization ofhydrogen has become an important issue, the only alterna-tive being loss of operating flexibility and further erosion ofalready tight profit margins.
Hydrogen management using the techniques of pinchanalysis helps find solutions that lead to reduced capitaloutlay, lower operating costs, lower emissions, improvedproduct quality and increased yields/capacity. The toolsinclude H2 surplus diagrams, short-cut simulations and LP-optimization.
H2 surplus diagrams set targets for fresh hydrogen con-sumption, identify bottlenecks in the distribution systemand highlight opportunities for improved utilizationthrough redistribution and recovery. Short-cut modeling isused to produce overall H2 balances, and LP tools are usedfor network optimization. Typical savings are 5 to 10% offresh hydrogen consumption (Linnhoff, Tainsh andWasilweski 1999) and (AspenTechnology, 2000). Moreadvanced hydrogen network optimization techniques treathydrogen-rich gas streams as multi-component mixtures tomore accurately reflect the differing behaviors of compo-nents such as methane, ethane and propane (Hallale et al.2003).
Complex Distillation Systems
General methodologies have been developed, and continueto be developed, for:
• Optimum sequencing of distillation columns for sepa-rating multi-component mixtures, typical of oil refineryand petrochemical plants.
• Complex column configurations, eg. side strippers, pre-fractionation (Petyluk) column, divided-wall column,side condensers and side reboilers.
• Integrated design of the crude oil distillation unit withthe preheat train.
• Azeotropic column design using residue curve maps.Most of these methods incorporate both pinch analysis
techniques, as well as more conventional techniques toachieve the optimum design. In new design, full thermalintegration typically saves 30 percent of the energy and 15to 20 percent of the capital cost compared to conventionalarrangements.
18 SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004
Fig. 7. Example of a complex column.
FP2
P3
P1
P4
Fig. 8. Reaction-separation-recycle system.
Reactor 1
Reactor 2
F
P2
P1
Reaction Systems
The traditional way to boost energy efficiency is to reduceenergy input for a given process configuration. The concepthere is somewhat different; the objective is to increase theprocess yield for a given energy input. This is the latest areaof research for application of optimization techniques basedon the concept of pinch analysis.
Methodologies are being developed for the systematicdesign of chemical reactors, which set performance targetsfor yield and catalyst selectivity. For new processes, one canidentify the optimal reactor configuration and operation.For existing processes, one can determine the potentialimprovements from modifying the design. The methodologyfrequently results in novel reactor schemes that would bevirtually impossible to derive by trial and error (Dept ofProcess Integration, University of Manchester Institute ofScience & Technology, Manchester, U.K. 2003).
Research is also being conducted on the synthesis of opti-mum structures for combined reaction-separation-recyclesystems and on reactive distillation.
BENEFITS
The benefits of pinch analysis, when retrofitting an existingplant include:
• Lower energy consumption, due to better thermal inte-gration.
• Lower energy costs, due to lower consumption, as wellas shifting load from higher to lower cost utilities.
• Lower emissions of combustion products (i.e., NOx,SOx, CO2).
• Lower emissions of CHP system wastes such as boilerand cooling tower blowdown.
• Capacity debottlenecking of energy utilities such as boil-
ers, furnaces, cooling towers and refrigeration systems.• Capacity debottlenecking of distillation columns and
batch processes.• Reduced freshwater consumption and wastewater
effluent flow.• Capacity debottlenecking of the wastewater treatment
system (with attendant capital cost savings).• Improved process yields from optimizing reaction-
separation systems.• Improved hydrogen utilization and profitability in oil
refining operations.In new plant designs or plant expansions, it is possible to
reduce capital costs by 5 to 10% and to compress thedesign/construction schedule by one to two months,(Kumana, J.D. Unpublished results).
TRACK RECORD
Pinch analysis has been successfully used across the fullspectrum of the chemical process industries. These indus-tries include:
• Oil refining and gas processing.• Petrochemicals.• Pharmaceuticals.• Fertilizers and pesticides.• General organic chemicals.• Polymers and fibers.• Inorganic chemicals.• Pulp and paper.• Synthetic fuels from coal.• Food processing.• Minerals and metals.To accelerate the adoption of pinch analysis by industry,
governmental agencies and trade organizations such as theU.S. Department of Energy (DOE) and the Electric PowerResearch Institute (EPRI) in the U.S., and the EnergyTechnology Support Unit (ETSU) in the U.K., sponsoredover 50 case studies in the early 1990s to prove the technol-ogy (see table 1).
Despite all its merits and adoption by several of the moreprogressive companies, especially in the chemical and petro-leum industry, pinch analysis has not penetrated small tomedium size companies, which constitute the vast majorityof energy and resource consumers. One can only speculateas to why this is so.
The principal barriers to more rapid and widespreadacceptance of pinch analysis appear to be due primarily topersistent myths and misconceptions in the minds of techni-cal managers:
• Pinch analysis is about “heat exchanger design.”• The existing process has already been “optimized” for
heat recovery, so there can be no further scope for ener-
SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004 19
Fig. 9. Reactive distillation.
Stripper
Reaction zone
Rectifier
P2
F 2
F 1
P1
gy cost savings.• Additional heat recovery will not be economic unless
fuel prices are “high.”• A high degree of integration will cause problems with
operating flexibility and product quality.First, we hope we have demonstrated that pinch analysis
is not about “heat exchangers,” but is a general techniquefor optimizing process topology. It is high time this perni-cious myth is dispelled.
Second, it is important to understand that there are twokinds of optimization - structural and parametric. In para-metric optimization, the process topology itself is fixed, andthe focus is on selecting the best combination of parametervalues (flow rates, temperatures, compositions) that result inthe lowest operating cost. This is the traditional way. Pinchanalysis, on the other hand is used to address the processtopology itself and determine the optimum equipment con-figuration to start with. This is called structural optimiza-tion. Typically, the gains in efficiency from structural opti-mization are in the range of 15 to 35%, compared to 3 to7% for parametric optimization (Kumana, J.D. Unpublishedresults). Structural and parametric optimization are comple-mentary; for best results, one should use both.
Third, when done correctly, the relative costs of capitaland energy (or water) are already built into the equation, sothe issue of high or low energy costs does not even arise.The design will always be optimum for the prevailing site-specific economic conditions.
Fourth, a “high” degree of integration is not necessarilythe correct design. In a good design, there is a balancebetween capital costs and operating costs that include notonly energy, but productivity (e.g., downtime due to foul-ing, quality loss due to control excursions, maintenancecosts, etc.) and safety and reliability issues. Pinch analysisoffers a way to quantify these impacts in a systematic man-ner. The ultimate design decision remains in the hands ofthe engineer and project manager, as it should.
There could also be another significant factor. Successfulapplication requires a high degree of skill and experience.Only a handful of companies can afford to maintain an in-house team of this caliber. For the rest, the best option is tohire engineering firms and individual consultants who spe-cialize in pinch analysis, even though they may charge dearlyfor their premium high-tech services. Whenever managementhas elected to take the cheap route and asked unqualifiedpeople to do such work, the results have been disappointingand have unfairly sullied the reputation of pinch analysis.
FUTURE DEVELOPMENTS
Research in pinch analysis and process integration got itsstart just over 20 years ago at the University of Manchester
Institute of Science and Technology (UMIST), inManchester, U.K. UMIST remains the undisputed leader forcontinuing research progress in the field. Although individ-ual professors at other universities in the Americas, Europeand Asia have shown interest, no other institution hasmatched the output of UMIST in either quality or quantity.The UMIST Process Integration Research Consortium, con-sisting of about 25 major international companies (includ-ing Saudi Aramco), provides funding for research and devel-opment in the field.
New process integration techniques, applications, andsoftware continue to consistently pour out of this program.
Governmental support for promoting industrial energyefficiency has been on the wane in the U.S. and U.K. sinceits heyday in the early 1990s, but the energy efficiencymovement is gathering momentum at the international level.The International Energy Agency (IEA) counts 23 membercountries and has initiated several “implementing agree-ments” to establish benchmarks for, promote awareness ofand provide training in energy technology.
SUMMARY AND CONCLUSIONS
Process optimization is a two-step activity:1. Optimization of the process topology, followed by2. Optimization of process parameters.Pinch analysis is the most successful tool by far for opti-
mizing process topology, as amply demonstrated by the con-sistently superior results obtained in a wide range of indus-tries and design problems. It would behoove the processdesign community to adopt and institutionalize these tech-niques and tools as rapidly as possible, not only for compet-itive economic advantage, but the corollary environmentalbenefits that automatically accrue.
The tools are available. All that is needed is the will andthe wisdom to use them.
20 SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004
Table 1. Summary of Demonstration Study Results
Industry# of
Plants
% Cost Savings PaybackRange, yrsAvg Range
Oil Refining 9 29 10-40 0.6-2.8
Chemicals 17 32 15-40 0.9-4.3
Food & Beverage 18 25 7-45 0.7-3.9
Pulp & Paper 9 18 10-35 0.8-2.4
Textiles & Fibers 4 12 3-25 1.1-4.7
Iron & Steel 2 31 11-50 0.9-1.5
Total 59 24.5
ACKNOWLEDGEMENT
The authors thank the management of Saudi Aramco, espe-cially Waleed A. Al-Rumaih, for his encouragement andsupport in the preparation of this paper.
NOMENCLATURE
Combined heat and power system CHPU.S. Department of Energy DOEElectric Power Research Institute, U.S. EPRIEnergy Technology Support Unit, U.K. ETSUHeat exchanger network HENInternational Energy Agency, France IEAMinimum approach temperature MATProcess flow diagram PFDVolatile organic compound VOCUniversity of Manchester Institute of Science and Technology, Manchester, U.K. UMIST
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AspenTechnology, (2000). “Refinery HydrogenManagement,” a series of technical briefs published byAspen Technology Inc., Boston, Mass.
Buehner, F., and J.D. Kumana, (1996). “Freshwater andWastewater Minimization: Concepts, Software andResults,” Proc. Chemputers Conf., Houston, March.
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EPRI publication no. TA-114453, (1999). “Process WaterReduction using Water Pinch Technology.”
El-Halwagi, M., (1997). Pollution Prevention ThroughProcess Integration, Academic Press.
Hallale, N., I. Moore and D. Vauk, (2003). “HydrogenOptimization at Minimal Investment,” PetroleumTechnology Quarterly, spring edition.
Karp, A., M. Rutkowski and C. Wells, (1989).“Debottlenecking of Refinery Units Using PinchTechnology,” Energy Processing Canada, July/August.
Kumana, J.D. and A.H. Al-Qahtani, (2003). “Optimizationof Process Topology Using Pinch Analysis,” FirstInternational Symposium on Exergy, Energy andEnvironment, Izmir, Turkey, July.
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Kumana, J.D., (1996). “Water Conservation andWastewater Minimization Through Process Integration,”Paper 57m at 5th World Chemical Engineering Congress,San Diego, Calif., July.
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Linnhoff, B., R. Tainsh and M. Wasilweski, (1999).“Hydrogen Network Management – A SystemsApproach,” paper at European Refinery TechnologyConference, Paris, France, November.
Linnhoff, B., (1994). “Use Pinch Analysis to Knock DownCapital Costs and Emissions,” Chem Eng Prog, August.
Linnhoff, B. et al. (1994). User Guide on ProcessIntegration for the Efficient Use of Energy, GulfPublishing Co., Houston.
Morgan, S., (1992). “Use Process Integration to ImproveProcess Designs and the Design Process,” Chem EngProg., September.
Nath, R., J.D. Kumana and J. Holliday, (1992). “OptimumDispatching of Plant Utility Systems to Minimize Costand Local NOx Emissions,” ASME Proc: Ind PowerConf, New Orleans.
Obeng, E. and G. Ashton, (1988). “On Pinch TechnologyBased Procedures for the Design of Batch Processes,”Chemical Engineering Research Design, May.
Rossiter, A. (ed), J.D. Kumana, et al., (1995). WasteMinimization through Process Design, McGraw-Hill,New York.
Rudman, A., (1995). “Process Integration: Planning yourTotal Site,” Chemical Technology Europe(January/February).
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SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004 21
Smith, R., (1995). Chemical Process Design, McGraw-HillInc, New York.
www.worldwaterforum.org website.
ADDITIONAL READING
Alanis, F. and I. Sinclair, (2002). “Understanding Processand Design Interactions: The Key to EfficiencyImprovement and Low Cost Revamps in EthylenePlants,” Fourth European Petrochemicals TechnologyConference, June.
Alves, J.J. and G.P. Towler, (2002). “Analysis of RefineryHydrogen Distribution Systems,” Ind. Eng. Chem. Res.,vol. 41, pp. 5,759-5,769.
Anon, (2001). “Let’s Work Together (DSM Utilities SuccessStory),” European Chemical News, June.
Asante, N. and X.X. Zhu, (1996). “An AutomatedApproach for Heat Exchanger Retrofit Featuring MinimalTopology Modifications,” Computers & Chem. Eng., vol.20 supp., pp. S7-S12.
Bagajewicz, M., (1997). Paper 132 C, AIChE SpringMeeting, New Orleans.
Birchfield, G., (2002). “Energy Management – Now is theTime,” AspenWorld Conf., October.
Bray, R., (2002). “A Novel Approach to EnergyOptimization and Management,” AspenWorld Conf.,October.
Castillo, F., D. Thong and G. Towler, (1998).“Homogeneous Azeotropic Distillation: 1. DesignProcedure for Single-Feed Columns at Nontotal Reflux,”Ind. Eng. Chem. Res., vol. 37, no. 3, pp. 987-997.
Dave, D., (2003). “Scheduling of Refinery Operations,”24th Process Integration Research Consortium annualmeeting, Manchester, U.K., October.
Dhole, V., I. Sinclair, C. Kaady and K. Semant, (2002).“Integrated Thermal and Hydraulic Analysis ofDistillation Columns,” Proc. of the 24th IndustrialEnergy Technology Conference, Houston, April.
Dhole, V., D. Seiller and K. Garza, (2002). “Utility SystemManagement and Operational Optimization,” Proc. of24th Industrial Energy Technology Conf., Houston, April.
DOE Press Release, (2001). “Integration of AdvancedTechnologies will Update Ethylene Plants,” September,(joint project by AspenTech, Air Products and ChemicalsInc, and British Petroleum).
Gadalla, M., M. Jobson and R. Smith, (2002). “A systemat-ic approach to increasing capacity and decreasing energydemand of existing refinery distillation systems,” Paper38b, AIChE Spring Meeting, New Orleans, March.
Glass, K., V. Dhole and Y. P. Wang, (2002). “IntegratedApproach to Revamping Heat Exchanger Networks,”Proc. of 24th Industrial Energy Technology Conf.,Houston, April.
Goldratt, E.M., (1992) The Goal, second ed., North RiverPress, Great Barrington, Mass.
Hallale, N., (2001). “Trends in Process Integration,” Chem.Eng. Prog., July.
Hallale, N., I. Moore and D. Vauk, (2002). “Hydrogen:Liability or Asset?” Chem. Eng. Prog., September.
In-de-Braak, J., (2002). “Energy and UtilitiesOptimization,” AspenWorld Conf., October.
Kumana, J.D.,(2001). “A Critical Comparison ofAlternative Methods for HEN Retrofit Design,” 51stCanadian Congress of Chemical Engineering, Halifax,Nova Scotia, October.
Kumana, J.D., (2001). “Use Spreadsheet-based CHPModels to Identify and Evaluate Energy Cost ReductionOpportunities in Industrial Plants,” Proc. of 23rdIndustrial Energy Technology Conference, Houston, May.
Lee, D.H. (2002). “10% Energy Reduction in ModernAromatics Complex through Energy Integration,” SGCAromatics project, AspenWorld Conf., October.
Lee, Y.G., (2002) “Asset Optimization: A Better Approachfor Energy Saving and Capacity Increase,” AspenWorldConference, October.
Liebmann, K., V.R. Dhole and M. Jobson, (1998).“Integrated Design of a Conventional Crude OilDistillation Tower Using Pinch Analysis,” Trans I ChemE, vol. 76 part A, pp. 335-347, March.
Maxell, M., (2001). “Modeling Hydrogen Synthesis withRigorous Kinetics as part of Plant Wide Optimization,”ACS National Meeting, August.
Moore, I., (2002). “Engineering Tools & ProjectMethodologies for Refinery Sitewide Improvements,”AspenWorld Conf., October.
22 SAUDI ARAMCO JOURNAL OF TECHNOLOGY WINTER 2004
Moore, I., N. Hallale and L. Turpin, (2002).“Misconceptions that Lead to Failure,” HydrocarbonEngineering, October.
Nie, X.R. and X.X. Zhu, (1999). “Heat ExchangerNetwork Retrofit Considering Pressure Drop and Heat-Transfer Enhancement,” AIChE Journal, vol. 45, no.6,pp. 1,239-1,254.
Pandit H. and R. Cassidy, (2001). “Hydrogen: Under NewManagement,” Hydrocarbon Engineering, November.
Petela, E.A. and R. Cassidy, (2001). “Life Cycle UtilitiesManagement,” NPRA Annual Technical Meeting, SanAntonio, Texas.
Petela, E. and A. Eccleston, (2001). “Optimization ofRefinery Utility Systems for Cost and EmissionReduction,” ERTC Environmental Conference, Vienna,Austria, April.
www.pinchtechnology.com website - more than 50 articleson all aspects of process optimization based on pinchanalysis.
“Reducing Energy Consumption and Costs,” PetroleumReview, (July 2002).
Reyneke, R., (2002). “Application of Process Synthesis toReal-World Design and Optimization,” AspenWorldConf. October.
Robinson, P., et al. (2000/2001). “Use of Rigorous Modelsin Refinery Wide Optimization,” Petroleum TechQuarterly, winter.
Robinson, P., (2002). “Use Rigorous Models to Enhance H2
Network Simulation and Optimization,” AspenWorldConf., October.
Swink, D., (2002). “Integrated Energy ManagementOptimization,” AspenWorld Conf., October.
Thong, D., F. Castillo and G. Towler, “Distillation Designand Retrofit Using Stage-Composition Lines,” Chem EngSci, vol. 55, pp. 625-640.
U.S. Dept of Energy, (2003). “How to Calculate the TrueCost of Steam,” Publ. No. DOE/GO-102003-1736,September.
Varbanov, P., (2003). “Synthesis of Site Utility Systems,”20th Process Integration Research Consortium annualmeeting, Manchester, U.K., October.
Zhu, X.X., M. Zanfir and J. Klemes, (1998). “HeatTransfer Enhancement for Heat Exchangers NetworksRetrofit,” paper presented at CHISA’98, 13thInternational Congress of Chemical and ProcessEngineering, Czech Republic, August.
