Desalination - Team A - Revision history

Pdtravan: /* Brine Heater */

2016-03-12T03:34:27Z

Brine Heater

← Older revision		Revision as of 03:34, 12 March 2016
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	==Brine Heater==		==Brine Heater==
	After the seawater exits the final heat exchanger, it enters a brine heater (E-119) where it is brought up to the temperature necessary for the flashing process to begin. This means that the seawater must be overheated compared to stage one, so that the seawater will flash in the evaporation chamber, i.e. release heat and vapor to reach equilibrium with stage conditions. After flowing through the condensers, the seawater enters the brine heater at 91.~~6 oC~~ and is heated to ~~120 oC~~. The overall system requires 2.31 x 106 kW of duty. This is supplied by a total of 4.15 x 106 kg per hour of steam.		After the seawater exits the final heat exchanger, it enters a brine heater (E-119) where it is brought up to the temperature necessary for the flashing process to begin. This means that the seawater must be overheated compared to stage one, so that the seawater will flash in the evaporation chamber, i.e. release heat and vapor to reach equilibrium with stage conditions. After flowing through the condensers, the seawater enters the brine heater at 91.6ºC and is heated to 120ºC. The overall system requires 2.31 x 106 kW of duty. This is supplied by a total of 4.15 x 106 kg per hour of steam.

	==Evaporation Chambers==		==Evaporation Chambers==

Pdtravan: /* Evaporation Chambers */

2016-03-12T03:33:33Z

Evaporation Chambers

← Older revision		Revision as of 03:33, 12 March 2016
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	Each respective heat exchanger fully condenses the vapor product stream from each stage. However, when all of the individual product streams are consolidated into the final combined product stream, some water exists in the vapor phase due to temperature and pressure changes associated with mixing all of the streams together. Although the vapor product stream from each stage condenses completely across its respective heat exchanger, the total product stream contains some water in the vapor phase due to the temperature change when the mixer sums all the streams. In order to fully condense this stream, which will be sent to local water treatment plans, a heat exchanger (E-120) is put in place to cool down the product using the process feed stream.		Each respective heat exchanger fully condenses the vapor product stream from each stage. However, when all of the individual product streams are consolidated into the final combined product stream, some water exists in the vapor phase due to temperature and pressure changes associated with mixing all of the streams together. Although the vapor product stream from each stage condenses completely across its respective heat exchanger, the total product stream contains some water in the vapor phase due to the temperature change when the mixer sums all the streams. In order to fully condense this stream, which will be sent to local water treatment plans, a heat exchanger (E-120) is put in place to cool down the product using the process feed stream.

	The correlations of El-Dessouky and Ettouney were employed in order to size the flash chambers. They specified that conventional MSF plants that operate at a capacity between 27,000 and 36,000 ~~m<sup>3</sup>~~/day use flashing stages of the dimensions 18 m diameter and 4 m height.<sup>6</sup>		The correlations of El-Dessouky and Ettouney were employed in order to size the flash chambers. They specified that conventional MSF plants that operate at a capacity between 27,000 and 36,000 m3/day use flashing stages of the dimensions 18 m diameter and 4 m height.<sup>6</sup>

	==Valves==		==Valves==

Pdtravan: /* Brine Heater */

2016-03-12T03:32:45Z

Brine Heater

← Older revision		Revision as of 03:32, 12 March 2016
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	==Brine Heater==		==Brine Heater==
	After the seawater exits the final heat exchanger, it enters a brine heater (E-119) where it is brought up to the temperature necessary for the flashing process to begin. This means that the seawater must be overheated compared to stage one, so that the seawater will flash in the evaporation chamber, i.e. release heat and vapor to reach equilibrium with stage conditions. After flowing through the condensers, the seawater enters the brine heater at 96.~~1 <sup>o</sup>C~~ and is heated to 120 ~~<sup>o</sup>C~~. The overall system requires 2.31 x ~~10<sup>6</sup>~~ kW of duty. This is supplied by a total of 4.15 x ~~10<sup>6</sup>~~ kg per hour of steam.		After the seawater exits the final heat exchanger, it enters a brine heater (E-119) where it is brought up to the temperature necessary for the flashing process to begin. This means that the seawater must be overheated compared to stage one, so that the seawater will flash in the evaporation chamber, i.e. release heat and vapor to reach equilibrium with stage conditions. After flowing through the condensers, the seawater enters the brine heater at 91.6 oC and is heated to 120 oC. The overall system requires 2.31 x 106 kW of duty. This is supplied by a total of 4.15 x 106 kg per hour of steam.

	==Evaporation Chambers==		==Evaporation Chambers==

Johnmarsiglio: /* Optimization */

2016-03-12T03:30:44Z

Optimization

← Older revision		Revision as of 03:30, 12 March 2016
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	The HYSYS economic analyzer was used to systematically optimize the process by finding the model with the lowest annualized utility cost. The performance parameters kept constant across each model were: the inlet composition, pressure, and temperature, the brine outlet temperature, the total product flow rate and composition, and the flash stage schematic. Table 1 displays the annualized utility cost for each model, and illustrates that a clear dip in the utility cost occurs in an 18 stage model. Thus, 18 is the optimal number of stages to use for our MSF distillation given utility costs as the optimized parameter.		The HYSYS economic analyzer was used to systematically optimize the process by finding the model with the lowest annualized utility cost. The performance parameters kept constant across each model were: the inlet composition, pressure, and temperature, the brine outlet temperature, the total product flow rate and composition, and the flash stage schematic. Table 1 displays the annualized utility cost for each model, and illustrates that a clear dip in the utility cost occurs in an 18 stage model. Thus, 18 is the optimal number of stages to use for our MSF distillation given utility costs as the optimized parameter.
	[[File:Table_1.PNG~~\|thumb~~\|center\|500x300px]]		[[File:Table_1.PNG\|center\|500x300px]]

	=Economic Evaluation=		=Economic Evaluation=

Pdtravan: /* Appendix B. HYSYS Simulation */

2016-03-12T03:27:55Z

Appendix B. HYSYS Simulation

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	=Appendix B. HYSYS Simulation=		=Appendix B. HYSYS Simulation=
	The ~~outputs of the~~ HYSYS model of the process is shown below.		The HYSYS model of the process is shown below.

	[[File:AppendB.PNG]]		[[File:AppendB.PNG]]

Ezhuang: /* Appendix G. Economic Analysis */

2016-03-12T03:27:11Z

Appendix G. Economic Analysis

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	=Appendix G. Economic Analysis=		=Appendix G. Economic Analysis=
			[[File:Econanalysis.PNG]]

Johnmarsiglio: /* Appendix E. MSF Stage Parameters */

2016-03-12T03:26:38Z

Appendix E. MSF Stage Parameters

← Older revision		Revision as of 03:26, 12 March 2016
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	[[File:Appendix E3.PNG]]		[[File:Appendix E3.PNG]]

	[[File:Appendix E4.PNG]]		[[File:Appendix E4.PNG]]

Johnmarsiglio: /* Appendix F. Process Units Calculations */

2016-03-12T03:26:30Z

Appendix F. Process Units Calculations

← Older revision		Revision as of 03:26, 12 March 2016
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	[[File:AppendF2.PNG]]		[[File:AppendF2.PNG]]

			[[File:AppendF3.PNG]]

	=Appendix G. Economic Analysis=		=Appendix G. Economic Analysis=

Johnmarsiglio: /* Appendix F. Process Units Calculations */

2016-03-12T03:25:46Z

Appendix F. Process Units Calculations

← Older revision		Revision as of 03:25, 12 March 2016
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	=Appendix F. Process Units Calculations=		=Appendix F. Process Units Calculations=
	[[File:AppendF.PNG]]		[[File:AppendF.PNG]]

			[[File:AppendF2.PNG]]

	=Appendix G. Economic Analysis=		=Appendix G. Economic Analysis=

Ezhuang: /* Introduction */

2016-03-12T03:25:01Z

Introduction

← Older revision		Revision as of 03:25, 12 March 2016
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	=Introduction=		=Introduction=
	An increasing global water scarcity is fueling initiatives everywhere for clean water treatment, making efficient seawater desalination an attractive aim for chemical plant design. A 2015 market analysis found that the global desalination market earned revenues of $11.66 billion, and this number is expected to reach over $19 billion by 2019. Furthermore, the 17,000 desalination plants currently in operation are expected to double in number by 2020.1		An increasing global water scarcity is fueling initiatives everywhere for clean water treatment, making efficient seawater desalination an attractive aim for chemical plant design. A 2015 market analysis found that the global desalination market earned revenues of $11.66 billion, and this number is expected to reach over $19 billion by 2019. Furthermore, the 17,000 desalination plants currently in operation are expected to double in number by 2020.<sup>1</sup>

	As fresh water sources become increasingly scarce, strict water conservation measures are being observed. California is entering the fourth year of one of its most severe droughts on record. Cities are required to reduce their water usage by 35% to avoid facing fines.2 In lieu of these pressing conditions, California is looking for ways to provide more accessible fresh water to its citizens. This high demand for clean water motivated our choosing Richmond, CA as our plant location. At Richmond, the desalination plant can convert readily available seawater from the San Francisco Bay into fresh water. We propose to desalinate 50 million gallons of water per day to be sent to water treatment plants for potability. This aim is based on the capacity of the desalination plant in Carlsbad, California, which services a similar population.		As fresh water sources become increasingly scarce, strict water conservation measures are being observed. California is entering the fourth year of one of its most severe droughts on record. Cities are required to reduce their water usage by 35% to avoid facing fines.<sup>2</sup> In lieu of these pressing conditions, California is looking for ways to provide more accessible fresh water to its citizens. This high demand for clean water motivated our choosing Richmond, CA as our plant location. At Richmond, the desalination plant can convert readily available seawater from the San Francisco Bay into fresh water. We propose to desalinate 50 million gallons of water per day to be sent to water treatment plants for potability. This aim is based on the capacity of the desalination plant in Carlsbad, California, which services a similar population.

	The salinity of the water in the San Francisco Bay is seasonal. During the dry seasons of summer and fall, salinity is high around 10 PSU (10,000 ppm) because water from the Pacific Ocean flows into the San Francisco Bay. During the wet winter season, fresh water from the rivers flows into the Bay, and salinity drops to around 2 PSU (2,000).3 Designed to meet the “worst case” scenario, our plant will process 398 million gallons of water per day with 10,000 ppm of salt to produce 50 million gallons of distilled water. This gives a yield of 13%.		The salinity of the water in the San Francisco Bay is seasonal. During the dry seasons of summer and fall, salinity is high around 10 PSU (10,000 ppm) because water from the Pacific Ocean flows into the San Francisco Bay. During the wet winter season, fresh water from the rivers flows into the Bay, and salinity drops to around 2 PSU (2,000).3 Designed to meet the “worst case” scenario, our plant will process 398 million gallons of water per day with 10,000 ppm of salt to produce 50 million gallons of distilled water. This gives a yield of 13%.