Process alternatives and flowsheeting - Revision history

Jian: /* References */

2015-03-02T04:22:29Z

References

← Older revision		Revision as of 04:22, 2 March 2015
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	==References==		==References==
	:Towler G, Sinnott R. Process Flowsheet Development. In: Chemical Engineering Design: Principles, Practice and Economics of Plant and Process Design. 2nd ed. Boston: Elsevier; 2013. p. 33–102.		Towler G, Sinnott R. Process Flowsheet Development. In: Chemical Engineering Design: Principles, Practice and Economics of Plant and Process Design. 2nd ed. Boston: Elsevier; 2013. p. 33–102.

Jian: /* References */

2015-02-24T21:30:00Z

References

← Older revision		Revision as of 21:30, 24 February 2015
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	==References==		==References==
	~~1. Gavin~~ Towler ~~and Ray~~ Sinnott~~, Chapter 2 –~~ Process Flowsheet Development, Chemical Engineering Design, 2nd Ed.~~, edited by Gavin Towler and Ray Sinnott, Butterworth-Heinemann,~~ Boston, 2013~~, Pages 33–102, ISBN 9780080966595, http://www~~.~~sciencedirect~~.~~com/science/article/pii/B9780080966595000079~~.		:Towler G, Sinnott R. Process Flowsheet Development. In: Chemical Engineering Design: Principles, Practice and Economics of Plant and Process Design. 2nd ed. Boston: Elsevier; 2013. p. 33–102.

Wlassman: /* Revamps of Existing Plants */

2014-03-03T01:15:32Z

Revamps of Existing Plants

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	Modification		Modification
	Improvements in the process economics are very desirable. This is usually achieved by improving following parameters: reactor selectivity, process yield, process energy efficiency, and process fixed costs. Capital investment and working capital can be reduced to give improved process economics as well. Other factors that can be improved on process designs are plant safety, reliability, and environmental impact. These factors can be achieved by substituting less hazardous material and using reliable pieces of equipment.		Improvements in the process economics are very desirable. This is usually achieved by improving following parameters: reactor selectivity, process yield, process energy efficiency, and process fixed costs. Capital investment and working capital can be reduced to give improved process economics as well. Other factors that can be improved on process designs are plant safety, reliability, and environmental impact. These factors can be achieved by substituting less hazardous material and using reliable pieces of equipment.

	~~==Revamps of Existing Plants==~~

	==Synthesis of Novel Flowsheets==		==Synthesis of Novel Flowsheets==

Wlassman: /* Process Flow Diagrams */

2014-03-03T01:14:39Z

Process Flow Diagrams

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	A PFD is typically organized to reflect the proposed layout of the chemical plant, with different layouts already being experimented with at this early phase of design.		A PFD is typically organized to reflect the proposed layout of the chemical plant, with different layouts already being experimented with at this early phase of design.

			[[File:pfd example.gif\|options\|]]

	===Piping and Instrumentation Diagrams===		===Piping and Instrumentation Diagrams===

Wlassman: /* Block Diagrams */

2014-03-03T01:14:09Z

Block Diagrams

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	===Block Diagrams===		===Block Diagrams===
	Block diagrams are usually generated very early in the design process, and utilize labeled boxes to illustrate process equipment. These diagrams communicate the general idea behind a process in terms of what types of equipment will be present, and what order the process stream passes through the equipment, but it does not contain detailed information regarding equipment design or stream conditions. Usually, material balance information and flow rates of many streams are available, but some streams may be unspecified. For this reason, they are not useful as final engineering schematics, but are more useful as a tool for communicating during early stages in process development.		Block diagrams are usually generated very early in the design process, and utilize labeled boxes to illustrate process equipment. These diagrams communicate the general idea behind a process in terms of what types of equipment will be present, and what order the process stream passes through the equipment, but it does not contain detailed information regarding equipment design or stream conditions. Usually, material balance information and flow rates of many streams are available, but some streams may be unspecified. For this reason, they are not useful as final engineering schematics, but are more useful as a tool for communicating during early stages in process development.

			[[File:BFD Example.gif\|options\|A simple example of a block flow diagram.]]

	===Process Flow Diagrams===		===Process Flow Diagrams===

Jianger: /* Overall Procedure for Flowsheet Synthesis */

2014-02-17T13:09:20Z

Overall Procedure for Flowsheet Synthesis

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	Design of completely new flowsheets are usually avoided due to the financial and safety risk they carry. Process synthesis attempt to minimize risk and maximize potential process such that the financial reward is greater than the risk. Process synthesis has been aided by process simulation programs as well as experience in similiar processes.		Design of completely new flowsheets are usually avoided due to the financial and safety risk they carry. Process synthesis attempt to minimize risk and maximize potential process such that the financial reward is greater than the risk. Process synthesis has been aided by process simulation programs as well as experience in similiar processes.

	===~~Overall~~ Procedure for Flowsheet Synthesis===		===Procedure for Flowsheet Synthesis===
	# Generate Process.		# Generate Process. Conduct initial design basis with as much of available data as possible.
	# Initial Economics.		# Initial Economics. Collect cost of feeds and price of products to determine profitability of process.
	# Set Yield Targets.		# Set Yield Targets. Estimate target yields in order to yield profitability.
	# Preliminary Economic Assessment.		# Preliminary Economic Assessment. Obtain a preliminary cost of production.
	# Refine Process Structure.		# Refine Process Structure. Create a complete PFD containing all processes and equipment.
	# PFD Review.		# PFD Review. Review PFD with a committee consisting of the design team and experts.
	# Preliminary Process Hazard Analysis (PHA).		# Preliminary Process Hazard Analysis (PHA). Identify hazard in the process and rectification steps.
	# Revise Economic Assessment.		# Revise Economic Assessment. Conduct economic assessment based on additional modification and ensure similar profit from products.
	# Optimization. While it might not be possible to have sufficient data to properly optimize the system at the time the design team is performing processes, the design team should optimize the design based on the data available. While it might be necessary to perform optimization on different sections of the process due to complexity, the overall optimization with advantages and disadvantages should be considered.		# Optimization. While it might not be possible to have sufficient data to properly optimize the system at the time the design team is performing processes, the design team should optimize the design based on the data available. While it might be necessary to perform optimization on different sections of the process due to complexity, the overall optimization with advantages and disadvantages should be considered.

Jianger: /* Conclusion */

2014-02-17T12:55:22Z

Conclusion

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	==Conclusion==		==Conclusion==
			Process alternatives and flowsheeting offers a methodological way of organizing and presenting design processes. Numerous tools has been introduced to aid with process presentation to offer organized design processes and allow further modification of them.

	==References==		==References==
	1. Gavin Towler and Ray Sinnott, Chapter 2 – Process Flowsheet Development, Chemical Engineering Design, 2nd Ed., edited by Gavin Towler and Ray Sinnott, Butterworth-Heinemann, Boston, 2013, Pages 33–102, ISBN 9780080966595, http://www.sciencedirect.com/science/article/pii/B9780080966595000079.		1. Gavin Towler and Ray Sinnott, Chapter 2 – Process Flowsheet Development, Chemical Engineering Design, 2nd Ed., edited by Gavin Towler and Ray Sinnott, Butterworth-Heinemann, Boston, 2013, Pages 33–102, ISBN 9780080966595, http://www.sciencedirect.com/science/article/pii/B9780080966595000079.

Jianger: /* Overall Procedure for Flowsheet Development */

2014-02-17T12:51:31Z

Overall Procedure for Flowsheet Development

← Older revision		Revision as of 12:51, 17 February 2014
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	# Follow-up. If there are unanswered questions which need to be addressed, the design team should perform the necessary analysis. Corrections made during the review should be noted and added to the PFD. Notes describing issues, concerns, and future steps should be distributed after the meeting adjourns.		# Follow-up. If there are unanswered questions which need to be addressed, the design team should perform the necessary analysis. Corrections made during the review should be noted and added to the PFD. Notes describing issues, concerns, and future steps should be distributed after the meeting adjourns.
	# More PFD Reviews. Depending on the number of changes performed during the review process, further review process may be necessary.		# More PFD Reviews. Depending on the number of changes performed during the review process, further review process may be necessary.

	~~==Overall Procedure for Flowsheet Development==~~

	==Conclusion==		==Conclusion==

Mki990: /* Selection Modification, and Improvement of Commercially-Proven Processes */

2014-02-17T04:08:36Z

Selection Modification, and Improvement of Commercially-Proven Processes

← Older revision		Revision as of 04:08, 17 February 2014
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	==Selection Modification, and Improvement of Commercially-Proven Processes==		==Selection Modification, and Improvement of Commercially-Proven Processes==
			Modification and Improvement of Processes
			When in designing processes, companies usually do not invest heavily on risk inherent project. They hire design teams that evaluate and optimize the different existing designs. The processes may need modification to fit the desired products such as addition or substitution of streams or interchange reactions and catalysts.
			Information on modification
			The chemical process industries are competitive, so the details of the processes are restricted and limited. Detailed information on reaction kinetics and process conditions can be found using the references such as Encyclopedia of Chemical Technology and Ullmann’s Encyclopedia of Industrial Technology. Patents are another useful information source on designing processes. Since the patent gives its owner the right of particular information, extracting the details may be limited. Other times, companies hire consulting firms to collect necessary information on designing processes.
			Modification
			Improvements in the process economics are very desirable. This is usually achieved by improving following parameters: reactor selectivity, process yield, process energy efficiency, and process fixed costs. Capital investment and working capital can be reduced to give improved process economics as well. Other factors that can be improved on process designs are plant safety, reliability, and environmental impact. These factors can be achieved by substituting less hazardous material and using reliable pieces of equipment.

	==Revamps of Existing Plants==		==Revamps of Existing Plants==

Mki990: /* The Anatomy of a Chemical Manufacturing Process */

2014-02-17T04:07:23Z

The Anatomy of a Chemical Manufacturing Process

← Older revision		Revision as of 04:07, 17 February 2014
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	==The Anatomy of a Chemical Manufacturing Process==		==The Anatomy of a Chemical Manufacturing Process==
			Chemical manufacturing process
			Components of a chemical process can be divided by these categories: raw material storage, feed preparation, reaction, product separation, purification, and product storage. Unless made on site or provided by neighboring companies, raw material or supply of reactant has to be bought and stored. The feeds have to be prepared and let the reaction run. The product has to be separated and maybe sometimes recycled. The product is purified as a product and is stored for its final usage or transportation.
			Continuous and batch processes
			Processes are usually continuous or batch. Batch processes are commonly used for food products, pharmaceutical products, personal care product, and specialty chemicals. Continuous processes are economical for large scale production. Batch allows production of multiple different products based on the reactor time; quality control is much easier. It is also easier to clean and maintain a sterility. Downside of the batch is that the scale of the production is limited and scale up is hard. Recycle and heat recovery is much harder, producing more waste byproduct and energy loss.
			Conversion and yield
			Conversion measures a fraction of the reagent that has reacted. Yield is a measure of a plant performance. Yield is usually defined by moles of product formed over moles of reactant times multiplied by a stoichiometric factor. One thing to note is that the conversion is related to reactants and yield is related to the products. Selectivity measures efficiency of the reactor in converting reagent to the desired product. It is calculated by moles of product produced over moles of product that could have been formed if all the reactant had converted completely.
			Recycles and Purges
			Recycle refers to processes in which a flow stream is returned to an earlier stage. This is common process when valuable reagent is not fully reacted; unreacted material is separated and added back. Recycle stream complicates the mass balance of the processes and necessitates a purge stream, which prevents a buildup of unwanted material in the process.

	==Selection Modification, and Improvement of Commercially-Proven Processes==		==Selection Modification, and Improvement of Commercially-Proven Processes==