mouza_alkaabi_multi-stage flash distillation system integrated with solar energy reverse engineering...

Masdar Institute of Science and Technology

ESM501 . Systems Architecture . Fall 2014

Multi-Stage Flash Distillation System Integrated with Solar Energy

Reverse Engineering of System Form

Mouza M. Al Kaabi

[email protected]

Engineering Systems and Management Masdar Institute of Science and Technology

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TABLE OF CONTENTS

1. Introduction .......................................................................................................................................... 3

1.1. Motivation and Relevance to the UAE .......................................................................................... 3

1.2. Water-Energy Nexus as System Context ....................................................................................... 4

1.3. System Boundary around Multi-Stage Flash Desalination ............................................................ 5

2. Mutli-Stage Flash Desalination Form modeling .................................................................................... 6

2.1. Modeling Strategy ......................................................................................................................... 6

2.1.1. Decompositional View of MSF .............................................................................................. 6

2.1.2. Decompositional View Of PTC .............................................................................................. 9

2.1.3. Structural View of MSF System ........................................................................................... 10

2.2. DSM of MSF System .................................................................................................................... 11

3. Conclusion ........................................................................................................................................... 12

4. Refrences ............................................................................................................................................ 13


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1. INTRODUCTION

1.1. Motivation and Relevance to the UAE

Civilizations throughout history have been known to establish and flourish near water sources,

and today water consumption is a valid indicator of the standard of living for any community.

Availability of water is considered a key issue for a country like the UAE, which is located in an

arid region with low and irregular rainfall and high level of evaporation. The recent developments

and the rapid urban growth, coupled with the increasing population have resulted in increased

consumption of large quantities of groundwater for irrigation, industrial and domestic usages,

leading to a 18% ground water reduction level since 2003.

UAE water resources can be classified into

conventional and non-conventional water

resources as illustrated in figure 1. The natural

resources such as surface water and groundwater

fall under the conventional water resources, while

the non-conventional water resources are

produced through artificial processes consisting of

desalinated water and treated wastewater. The

total consumption of water resources in the Emirate today exceeds 24 times its natural recharge

capacity. The desalinated water is providing for almost all the drinking water, while desalinated

water surplus is used for the artificial recharge of underground water, the aim is to increase the

current 48 hours drinking water reservoir to 90 days as a protection in case of an emergency. As

a result, the water planning and management in the UAE now combines both conventional and

nonconventional water resources. It is expected that the demand for desalinated water to almost

double by 2030. In 2010, there were eight seawater desalination plants in Abu Dhabi alone, and

more planned to be built to cover for the deficit in water supply. [1] [2] [3] [4] However, the

experience gained from the existing projects, coupled with the growing water and energy

demand, elevated the expectations in terms of optimization and innovation in constructing the

Figure 1: classification diagram of the water

resources in the UAE


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new desalination plants, while posing the question of whether it is feasible to retrofit legacy

desalination systems for higher efficiency.

This paper will analyze the form of one of the most prevailing water desalination technologies in

the UAE; Multi-Stage Flash system, while introducing a retrofitting scheme for the legacy

architecture by linking parabolic through solar collectors as a heat source, replacing the

conventional heating component produced for gas turbines, which is connected to electricity

production in the water-energy nexus.

1.2. Water-Energy Nexus as System Context

The electricity and water production

technologies are connected, they are

coupled to create the energy-water nexus as

illustrated in figure 2. Energy-water nexus

can be defined as “system-of-systems

composed of one infrastructure system with

the artifacts necessary to describe a full

energy value chain and another

infrastructure system with the artifacts

necessary to describe a full water value

chain.” The recent economic development, and population growth has derived an increase in the

demand of water and energy, in addition to the improvement in the standards related to

increasing efficiency of the legacy systems [5]. Analyzing the architecture form of the multi-stage

flash system, will require the consideration of the context that the system fall under and interact

with. The process used for desalination system, specifically the multi-stage flash system, is

integrated with the conventional process of electricity production where both require low

pressure heating steam extracted from power plants at low cost. [6]

This paper will consider that the system to be examined is contained within the water-energy

nexus, any retrofitting in form of the desalination legacy system will be connected to the energy

production system.

Figure 2 : System context and boundary


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1.3. System Boundary around Multi-Stage Flash Desalination

The multi-stage system is classified as a thermal process of desalination as shown in the

classification diagram in figure 3, thermal desalination accounts for 50% of the entire desalination

market, while thermal process require excessive amount of energy, the massive filed experience

in the thermal process used in desalination plants like MSF, provides a competitive production

cost compared to other desalination processes like reverse osmosis [6]. The multi-stage flash

system is constructed in cogeneration plants, where power and water are produced

simultaneously. The advantage of working with MSF is that the system provide the opportunity

to utilize renewable energy for heat addition, this paper will integrate the form of the legacy

multi-stage flash system with parabolic through solar collectors as a proposed retrofitting to

increase energy efficiency.

Figure 3 : Classification Of Desalination Systems based on process and energy sources required.


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2. MUTLI-STAGE FLASH DESALINATION FORM MODELING

Demonstrating a system or a product in a simplified abstraction is a critical step in developing,

refining alternative solutions, design languages provide an aid to a clear an efficient

representation of the system architecture. It is significant to present system architecture in a

quality method due to the impact of system architecture on downstream issues [7].

2.1. Modeling Strategy

This paper will use unified modeling language (UML) and Systems Modeling Language (SysML) to

represent the form of the Multi-stage flash system’s architecture, in addition to the parabolic

through solar collectors. The form of an architecture consists of structure elements; which

includes classes and components. The system of Multi-stage flash and parabolic solar collectors

will be represented in diagrams, the information represented in diagrams comparing to models

are incomplete. Nevertheless, diagrams provide an abstraction of the overall system to aid the

development of alternative scheme of a desalination system integrating renewable energy

source. [8]

This paper also utilize the method of design structure matrix (DSM), to visualize and analyze the

dependencies between the decomposed components of the multi-stage flash system, while

clarifying the approach to be followed to integrate the legacy system components with the

parabolic through solar collectors. [9]

2.1.1. Decompositional View of MSF

The first step in representing the architecture form is creating the decompositional diagram, the

process of decomposing the complex system provide an abstraction the needed develop the

system. Figure 4 to figure 7 represent the main components constructing the multi-stage flash

system’s architecture, a typical multi-stage flash consists of number flash chambers, the multi-

stage flash technology requires from 20 to 25 chambers at least, as the desalination efficiency

improves with the increase in number of champers, in addition to the increase of the cost of

initial construction works and the economic return. Hence, representing the system in the

decompositional view aid in analyzing cost and efficiency of the system, while studying the

benefit gained through life-cycle properties like flexibility through reconfigurability.


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Figure 4 : Decompositional View of Multi-stage flash system components.

Figure 5 : Decompositional View of Flash Chamber


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Figure 6 : Decompositional View of Brine Heater

Figure 7 : Decompositional View of Deaerator


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2.1.2. Decompositional View Of PTC

The other component to be integrated

with the multi-stage flash system is the

renewable energy source of heating; the

parabolic through collector. Figure 8

simplifies the way PTC operates, the

parabolic mirror reflects the sun radiation

into a focused point; which is the solar

radiation absorption system, consisting of

two pipes with vacuum in between, and

synthetic oil composite inside [10], the temperature at the vocal point is 70 times higher than the

normal sunlight [6]. The synthetic oil acts as a connection between the parabolic solar collector

and the multi-stage flash system at the brine heater which serve as an interface for that

connection.

The components of the PTC with their parts and properties are decomposed in figure 9, this

decomposition of the parabolic solar collector reveal the feasibility of integration of the system

as a heat source, as long as the systems can meet in a heat receiving interface; which is the brine

heater in this case.

Figure 8 : Illustration of the PTC system

Figure 9 : Decompositional View of PTC


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2.1.3. Structural View of MSF System

The structural view represent the components of the system with the dependencies between the

components, when representing the system form, the interfaces are distinguishable in

comparison with the decompositional view. The structure view illustrated in figure 10 reveal the

structure of the system, the function of the overall system can later be mapped by identifying

the behavior of components in connection with each other. Although the structural view

illustrate the direct connection between the components, yet the amount of information that

can be extracted from the diagram is limited to the general overview of the overall dependencies.

Hence, the next step would be to map the design structure matrix to reveal the characteristics of

the system that would aid in the decision making process.

Figure 10 : Structural View of the MSF heated by MSF


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2.2. DSM of MSF System

Design Structure matrix is representation of the structural interrelationship of system

components, using a two-dimensional format, to reveal the dependency between the

components [11]. The DSM used to describe the MSF system in figure 11 is object-based, most

of the relationships between the system components representing the form are coupled, as the

structural view presented previously, the components are connected with the main fluids

running through the system, which are the seawater, the brine and the fresh water. As the

number of components increase with the increase of the system complexity, the DSM offer an

advantage of modularity that aid in the control of emerging processes, which increase the

robustness and the resilience of the system. The multi-stage flash with the connection to

parabolic solar collectors represented here is considered a closed system, but if the system was

to be integrated with the electricity production, then the DSM can adapt with the increasing

complexity with minimal disruption [12].

Figure 11 : DSM of MSF integrating PTC


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3. CONCLUSION

This paper provided an over view of the system architecture form of multi-stage flash system,

integrated with parabolic solar collector as a source of heat used for the desalination process.

The modeling strategy utilized the unified modeling language (UML) and Systems Modeling

Language (SysML) to represent the elements and the structure of the system, through

decomposing the different components and classes then providing an over view of the interfaces

connection in a structural view diagram. However, advanced characteristics of the system can be

identified using the design structure matrix, all the components of both multi-stage flash and the

parabolic through collector, and mapping the interrelationships in between the components.

Analyzing the form of the multi-stage flash using the previously mentioned methods, reveal a

feasible coupling between the legacy system of multi-stage flash and the use of parabolic solar

collector, or any type of other clean source of heat. Using the brine heater as an interface

between the legacy system and the renewable source.

Nevertheless, the abstract level of representation in this paper is not enough to confirm the

validation of this proposed integration between multi-stage flash and parabolic solar collectors.

The presented diagrams mapped only the system form, the following step would be to represent

the system behavior through representing the system function.


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4. REFRENCES

[1] Environment Agency - Abu Dhabi, "THE WATER RESOURCES MANAGEMENT STRATEGY FOR THE EMIRATE OF ABU DHABI

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Water-Resources-Management-Strategy-for-the-Emirate-of-Abu-Dhabi-2014-2018-Eng1.pdf. [Accessed 8 11 2014].

[2] WAM, "uae interact," UAE National Media Council, 22 3 2009. [Online]. Available:

http://www.uaeinteract.com/docs/EAD_warns_against_depletion_of_Abu_Dhabis_water_resources_within_next_50_y

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[5] W. Lubega and A. Farid, "Quantitative engineering systems modeling and analysis of the energy–water nexus," Applied

Energy, vol. 135, p. 142–157, 2014.

[6] A. Cipollina, G. Micale and L. Rizzuti, Seawater Desalination:Conventional and Renewable Energy Processes, Palermo:

Springer, 2009.

[7] M. Van Wie, P. Rajan, M. Campbell, R. Stone and K. Wood, "REPRESENTING PRODUCT ARCHITECTURE," in ASME 2003

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[8] T. Weilkiens, Systems Engineering with SysML/UML: Modeling, Analysis, Design, Heidberg: Morgan Kaufmann, 2008.

[9] Institute of Product Development, "dsmweb.org," Institute of Product Development, 2009. [Online]. Available:

http://www.dsmweb.org/. [Accessed 9 11 2014].

[10] A. Hegazy and M. ElMadany, "DESIGN AND EXPERIMENTAL TESTING OF A SOLAR PARABOLIC TROUGH COLLECTOR WITH

ITS TRACKING SYSTEM FOR SALT-WATER DESALINATION IN ARID AREAS OF SAUDI ARABIA," in Saudi Engineering

Conference, Riyadh, 2007.

[11] O. d. Weck, "MIT Education," 2012. [Online]. Available: http://ocw.mit.edu/courses/engineering-systems-division/esd-36-

system-project-management-fall-2012/lecture-notes/MITESD_36F12_Lec04.pdf. [Accessed 9 11 2014].

[12] T. Browning, "The Design Structure Matrix: A Tool for Managing Complexity," scientific american, 15 9 2012. [Online].

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complexity/. [Accessed 9 11 2014].

[13] A. Santhosh, A. Farid and K. Youcef-Toumi, "Real-time economic dispatch for the supply side of the energy-water Nexus,"

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[15] A. Khawaji, I. Kutubkhanah and J.-M. Wie, "Advances in seawater desalination technologies," ScienceDirect, vol. 221, p.

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mouza_alkaabi_multi-stage flash distillation system integrated with solar energy reverse engineering...

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