Column - Revision history

Benjkg: /* Distillation */

2016-02-21T07:33:06Z

Distillation

← Older revision		Revision as of 07:33, 21 February 2016
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	Distillation is by far the most common separation process in practice, separating based on vapor-liquid equilibrium. The process is very effective in separating liquid components, as long as they have different boiling points and do not have an azeotrope. Distillation often requires high temperatures, so operating costs can be relatively high compared with other processes. However, distillation does not require any additional separation-aiding streams such as solvent, and as such does not require an additional utility to complete the separation as absorption and extraction do.		Distillation is by far the most common separation process in practice, separating based on vapor-liquid equilibrium. The process is very effective in separating liquid components, as long as they have different boiling points and do not have an azeotrope. Distillation often requires high temperatures, so operating costs can be relatively high compared with other processes. However, distillation does not require any additional separation-aiding streams such as solvent, and as such does not require an additional utility to complete the separation as absorption and extraction do.

	Distillation columns are accompanied by a reboiler at the bottom and a condenser at the top. The condenser can be a total condenser, resulting in one liquid distillate stream, or a partial condenser, resulting in a liquid distillate stream and a gaseous overhead stream. These components are the major energy consuming components of a distillation column. The liquid exiting the condenser is split into two streams: reflux and distillate. The proportion of liquid returning to the column relative to the liquid leaving as distillate is a key design parameter of the column, known as reflux ratio.		Distillation columns are accompanied by a reboiler at the bottom and a condenser at the top (see Figure 1). The condenser can be a total condenser, resulting in one liquid distillate stream, or a partial condenser, resulting in a liquid distillate stream and a gaseous overhead stream. These components are the major energy consuming components of a distillation column. The liquid exiting the condenser is split into two streams: reflux and distillate. The proportion of liquid returning to the column relative to the liquid leaving as distillate is a key design parameter of the column, known as reflux ratio.

	Each stage of a distillation column exists under its own conditions and equilibrium. The design of the tray itself can also critically impact the performance of the column. This capability exists in HYSYS, though the focus of this page's tutorials is on more general operation of the column. <ref name = "Wankat" />		Each stage of a distillation column exists under its own conditions and equilibrium. The design of the tray itself can also critically impact the performance of the column. This capability exists in HYSYS, though the focus of this page's tutorials is on more general operation of the column. <ref name = "Wankat" />

Benjkg: /* Distillation */

2016-02-21T07:32:42Z

Distillation

← Older revision		Revision as of 07:32, 21 February 2016
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	===Distillation===		===Distillation===
	Distillation is by far the most common separation process in practice, separating based on vapor-liquid equilibrium. The process is very effective in separating liquid components, as long as they have different boiling points and do not have an azeotrope. Distillation often requires high temperatures, so operating costs can be relatively high compared with other processes. However, distillation does not require any additional separation-aiding streams such as solvent, and as such does not require an additional utility to complete the separation as absorption and extraction do. <ref name = "Wankat" />		Distillation is by far the most common separation process in practice, separating based on vapor-liquid equilibrium. The process is very effective in separating liquid components, as long as they have different boiling points and do not have an azeotrope. Distillation often requires high temperatures, so operating costs can be relatively high compared with other processes. However, distillation does not require any additional separation-aiding streams such as solvent, and as such does not require an additional utility to complete the separation as absorption and extraction do.

			Distillation columns are accompanied by a reboiler at the bottom and a condenser at the top. The condenser can be a total condenser, resulting in one liquid distillate stream, or a partial condenser, resulting in a liquid distillate stream and a gaseous overhead stream. These components are the major energy consuming components of a distillation column. The liquid exiting the condenser is split into two streams: reflux and distillate. The proportion of liquid returning to the column relative to the liquid leaving as distillate is a key design parameter of the column, known as reflux ratio.

			Each stage of a distillation column exists under its own conditions and equilibrium. The design of the tray itself can also critically impact the performance of the column. This capability exists in HYSYS, though the focus of this page's tutorials is on more general operation of the column. <ref name = "Wankat" />

	==Simulating Separations in HYSYS==		==Simulating Separations in HYSYS==

Benjkg: /* Background */

2016-02-21T07:24:43Z

Background

← Older revision		Revision as of 07:24, 21 February 2016
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	===Absorption===		===Absorption===
	Absorption is primarily used to separate a solute from a stream in the gas state. The separation is conducted by introducing an additional liquid solvent stream to absorb the solute from the gas stream. Note that to reduce costs, the liquid solvent is often desirable to be extracted after this separation, so absorption is typically accompanied by a second separation process such as stripping to recover the liquid solvent from the solute. <ref name = "Wankat"> Wankat, P.C. Separation Process Engineering. Upper Saddle River: Prentice-Hall; 2012 </ref>		Absorption is primarily used to separate a solute from a stream in the gas state. The separation is conducted by introducing an additional liquid solvent stream to absorb the solute from the gas stream. Selection of this solvent is critical to the effectiveness of the separation. Note that to reduce costs, the liquid solvent is often desirable to be extracted after this separation, so absorption is typically accompanied by a second separation process such as stripping to recover the liquid solvent from the solute. <ref name = "Wankat"> Wankat, P.C. Separation Process Engineering. Upper Saddle River: Prentice-Hall; 2012 </ref>

	===Extraction===		===Extraction===
	Liquid-liquid extraction is typically used when distillation is unfeasible, such as separating components with an azeotrope or with very similar boiling points. Like absorption, liquid-liquid extraction requires the introduction an additional liquid solvent stream to separate one of the components. Physically, this separation occurs by difference in solubility of the components in the solvent. Also similar to absorption, the use of a solvent is often accompanied by an additional separation process like distillation to recover the solvent from the solute. <ref name = "P&T"> Peters M.S., Timmerhaus K.D. Plant Design and Economics for Chemical Engineers. 5th ed. New York: McGraw Hill; 2003. </ref>		Liquid-liquid extraction is typically used when distillation is unfeasible, such as separating components with an azeotrope or with very similar boiling points. Like absorption, liquid-liquid extraction requires the introduction an additional liquid solvent stream to separate one of the components. Again, selection of this solvent is critical to the effectiveness of the separation. Physically, this separation occurs by difference in solubility of the components in the solvent. Also similar to absorption, the use of a solvent is often accompanied by an additional separation process like distillation to recover the solvent from the solute. <ref name = "P&T"> Peters M.S., Timmerhaus K.D. Plant Design and Economics for Chemical Engineers. 5th ed. New York: McGraw Hill; 2003. </ref>

	===Distillation===		===Distillation===

Benjkg: Added background into distillation

2016-02-21T07:22:37Z

Added background into distillation

← Older revision		Revision as of 07:22, 21 February 2016
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	===Distillation===		===Distillation===
			Distillation is by far the most common separation process in practice, separating based on vapor-liquid equilibrium. The process is very effective in separating liquid components, as long as they have different boiling points and do not have an azeotrope. Distillation often requires high temperatures, so operating costs can be relatively high compared with other processes. However, distillation does not require any additional separation-aiding streams such as solvent, and as such does not require an additional utility to complete the separation as absorption and extraction do. <ref name = "Wankat" />

	==Simulating Separations in HYSYS==		==Simulating Separations in HYSYS==

Benjkg: Added background into extraction

2016-02-21T07:15:08Z

Added background into extraction

← Older revision		Revision as of 07:15, 21 February 2016
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	===Absorption===		===Absorption===
	Absorption is primarily used to separate a solute from a stream in the gas state. The separation is conducted by introducing an additional liquid solvent stream to absorb the solute from the gas stream. Note that to reduce costs, the liquid solvent is often desirable to be extracted after this separation, so absorption is typically accompanied by a second separation process such as stripping to recover the liquid solvent from the solute. <ref name = "Wankat"> Wankat, P.C~~. (2012)~~. Separation Process Engineering. Upper Saddle River: Prentice-Hall. </ref>		Absorption is primarily used to separate a solute from a stream in the gas state. The separation is conducted by introducing an additional liquid solvent stream to absorb the solute from the gas stream. Note that to reduce costs, the liquid solvent is often desirable to be extracted after this separation, so absorption is typically accompanied by a second separation process such as stripping to recover the liquid solvent from the solute. <ref name = "Wankat"> Wankat, P.C. Separation Process Engineering. Upper Saddle River: Prentice-Hall; 2012 </ref>

	===Extraction===		===Extraction===
			Liquid-liquid extraction is typically used when distillation is unfeasible, such as separating components with an azeotrope or with very similar boiling points. Like absorption, liquid-liquid extraction requires the introduction an additional liquid solvent stream to separate one of the components. Physically, this separation occurs by difference in solubility of the components in the solvent. Also similar to absorption, the use of a solvent is often accompanied by an additional separation process like distillation to recover the solvent from the solute. <ref name = "P&T"> Peters M.S., Timmerhaus K.D. Plant Design and Economics for Chemical Engineers. 5th ed. New York: McGraw Hill; 2003. </ref>

	===Distillation===		===Distillation===

Benjkg: Added background into absorption

2016-02-21T07:02:04Z

Added background into absorption

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 | [[File:ComponentSplitter.JPG|center|35px|]]|| Utility to force components to separate with no equilibrium considerations.
 |}
 ==Simulating Separations in HYSYS==

Benjkg: Repositioning images

2016-02-21T04:17:35Z

Repositioning images

Show changes

Benjkg at 06:03, 6 February 2016

2016-02-06T06:03:01Z

Benjkg at 06:02, 6 February 2016

2016-02-06T06:02:24Z

Benjkg: Adding figures for tutorial

2016-02-06T06:01:24Z

Adding figures for tutorial

← Older revision		Revision as of 06:01, 6 February 2016
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	# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.		# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.
	# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.		# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.
			[[File:Column_converged_initially.PNG\|thumb\|center}400px\|Figure 15. Initial column converged]]
	# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.		# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.
			[[File:Monitor_tab.PNG\|thumb\|center\|400px\|Figure 16. The monitor tab in HYSYS]]
	# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.		# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.
			[[File:Making_a_new_spec.PNG\|thumb\|center\|400px\|Figure 17. Creating a new specification for distillate methanol mole fraction]]
	# To add the recovery specification, the process is similar, expect the specification type is now "Column Component Recovery." To add the condenser and reboiler duty specifications, the spec type is "Column Duty," and the "Energy Stream" field should be chosen to be the energy stream of the condenser and reboiler for their respective specifications. Add these three specifications to the list as well.		# To add the recovery specification, the process is similar, expect the specification type is now "Column Component Recovery." To add the condenser and reboiler duty specifications, the spec type is "Column Duty," and the "Energy Stream" field should be chosen to be the energy stream of the condenser and reboiler for their respective specifications. Add these three specifications to the list as well.
	# Note that currently, the distillate methanol fraction is only 0.244. To begin manipulation column specifications to meet the requirement of 97% purity, change the currently empty specified value for this spec to the current value, 0.244. Then, deselect Distillate Rate as an active spec, and make this new purity spec active in its stead. The simulation should automatically and instantly converge - if not, hit run. After converging, all values should remain the same.		# Note that currently, the distillate methanol fraction is only 0.244. To begin manipulation column specifications to meet the requirement of 97% purity, change the currently empty specified value for this spec to the current value, 0.244. Then, deselect Distillate Rate as an active spec, and make this new purity spec active in its stead. The simulation should automatically and instantly converge - if not, hit run. After converging, all values should remain the same.
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	# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.		# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.
	# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.		# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.
			[[File:Requirements_met.PNG\|thumb\|center\|400px\|Figure 18. All design requirements met]]
	# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.		# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.
	# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.		# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.

← Older revision		Revision as of 06:03, 6 February 2016
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	# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.		# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.
	# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.		# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.
	[[File:Column_converged_initially.PNG\|thumb\|center\|~~400px~~\|Figure 15. Initial column converged]]		[[File:Column_converged_initially.PNG\|thumb\|center\|800px\|Figure 15. Initial column converged]]
	# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.		# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.
	[[File:Monitor_tab.PNG\|thumb\|center\|~~400px~~\|Figure 16. The monitor tab in HYSYS]]		[[File:Monitor_tab.PNG\|thumb\|center\|800px\|Figure 16. The monitor tab in HYSYS]]
	# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.		# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.
	[[File:Making_a_new_spec.PNG\|thumb\|center\|300px\|Figure 17. Creating a new specification for distillate methanol mole fraction]]		[[File:Making_a_new_spec.PNG\|thumb\|center\|300px\|Figure 17. Creating a new specification for distillate methanol mole fraction]]
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	# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.		# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.
	# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.		# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.
	[[File:Requirements_met.PNG\|thumb\|center\|~~600px~~\|Figure 18. All design requirements met]]		[[File:Requirements_met.PNG\|thumb\|center\|800px\|Figure 18. All design requirements met]]
	# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.		# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.
	# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.		# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.

← Older revision		Revision as of 06:02, 6 February 2016
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	# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.		# Place a standard distillation column in the simulation environment, and define a feed stream with vapor fraction 0, temperature 25 C, pressure 1 atm, flow rate 10 kgmol/h, and a composition of 0.2 mol fraction methanol and the balance of water.
	# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.		# Enter column setup. Define the column as having a total condenser, 8 stages, and the feed entering at stage 4. The column should be once-through with a regular reboiler. Condenser pressure should be 1 atm, while reboiler pressure will be set at 1.3 kPa, giving a small pressure drop through the column. Optional temperature estimates can be left empty. Reflux ratio should be specified as 1.5, and liquid rate as 8.2 kgmol/h. In a normal situation, many of these values can be initially estimated using a shortcut column and then using them here, in the first run of a standard column simulation. Finally, run the column simulation, and it should easily converge.
	[[File:Column_converged_initially.PNG\|thumb\|center}400px\|Figure 15. Initial column converged]]		[[File:Column_converged_initially.PNG\|thumb\|center\|400px\|Figure 15. Initial column converged]]
	# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.		# Now begins the refinement and optimization portion of the tutorial. To do so, in the distillation column window, switch to the Monitor tab in the Design toolbar on the left. We will add four new specifications of interest: distillate methanol purity, distillate methanol recovery, condenser duty, and reboiler duty.
	[[File:Monitor_tab.PNG\|thumb\|center\|400px\|Figure 16. The monitor tab in HYSYS]]		[[File:Monitor_tab.PNG\|thumb\|center\|400px\|Figure 16. The monitor tab in HYSYS]]
	# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.		# To add a new specification, click the button labeled "Add Spec..." at the bottom of the window. This first spec will be for distillate methanol purity. In the new popup window, choose "Column Component Fraction" from the list of specs. In the new window, the name of the spec can be changed, and the specification itself can be defined. Change "Target Type" to "Stream," change "Draw" to the distillate stream, and change "Component" to methanol. Close this window, and the new specification should now be included in the list on the main column window.
	[[File:Making_a_new_spec.PNG\|thumb\|center\|~~400px~~\|Figure 17. Creating a new specification for distillate methanol mole fraction]]		[[File:Making_a_new_spec.PNG\|thumb\|center\|300px\|Figure 17. Creating a new specification for distillate methanol mole fraction]]
	# To add the recovery specification, the process is similar, expect the specification type is now "Column Component Recovery." To add the condenser and reboiler duty specifications, the spec type is "Column Duty," and the "Energy Stream" field should be chosen to be the energy stream of the condenser and reboiler for their respective specifications. Add these three specifications to the list as well.		# To add the recovery specification, the process is similar, expect the specification type is now "Column Component Recovery." To add the condenser and reboiler duty specifications, the spec type is "Column Duty," and the "Energy Stream" field should be chosen to be the energy stream of the condenser and reboiler for their respective specifications. Add these three specifications to the list as well.
	# Note that currently, the distillate methanol fraction is only 0.244. To begin manipulation column specifications to meet the requirement of 97% purity, change the currently empty specified value for this spec to the current value, 0.244. Then, deselect Distillate Rate as an active spec, and make this new purity spec active in its stead. The simulation should automatically and instantly converge - if not, hit run. After converging, all values should remain the same.		# Note that currently, the distillate methanol fraction is only 0.244. To begin manipulation column specifications to meet the requirement of 97% purity, change the currently empty specified value for this spec to the current value, 0.244. Then, deselect Distillate Rate as an active spec, and make this new purity spec active in its stead. The simulation should automatically and instantly converge - if not, hit run. After converging, all values should remain the same.
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	# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.		# Repeat this process, increasing the number of stages again followed by increasing the purity, until the desired purity is met. In this example simulation, a purity specification of 0.97 can be met with 14 stages, with the feed entering at stage 7.
	# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.		# Recovery can be maximized in the same way, replacing Reflux Ratio as an active spec, though in this situation recovery is already 99.9%, so there is no need to maximize further.
	[[File:Requirements_met.PNG\|thumb\|center\|~~400px~~\|Figure 18. All design requirements met]]		[[File:Requirements_met.PNG\|thumb\|center\|600px\|Figure 18. All design requirements met]]
	# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.		# Now that the requirements are met, we can begin optimizing the number of stages and column duty. Condenser and reboiler duties are desired to be as low as possible to keep operating costs at a minimum, though number of stages should be kept relatively low as well. Note that with the current column setup, condenser duty is -1.83e5 kJ/h, and reboiler duty is 2.42e5 kJ/h.
	# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.		# To begin, set recovery as an active spec by specifying its value as the current value, in this case 0.999, and then deselecting Reflux Ratio as an active spec and selecting the custom recovery specification.