James Gremillion Author: James Gremillion One of the earliest applications of “computer control”, a now archaic term, on an ammonia plant was done in 1969 by Weissenfelder and Shah of Borden Chemical and IBM respectively. They were able to implement advanced control schemes in a computer that had proven to be too difficult to do in the pneumatic and electronic controllers of the time. Ammonia production increased, costs went down and the plant operators had better information to make decisions. I followed A.J. Weissenfelder at Borden Chemical in 1977 and one of the first things I found was that it was so much easier to modify the advanced control schemes on the computer than trying to change the configuration of board instruments. Modifications that were required because of plant changes, modernizations, etc. could be, and were, quickly implemented. Today we implement control schemes very similar to what Weissenfelder and Shah did but with vastly improved tools that have made the control schemes even easier to implement and much easier to modify. Further, many control system suppliers and consultants have packaged ammonia control schemes to allow proven solutions to be implemented very quickly. By Mbeychok , Ammonia Synthesis Diagram , CC BY-SA 3.0 The packages for the steam-methane reformer, for example, have the same control objectives as the early computer control schemes—maximize throughput, reduce methane leakage to a minimum and minimize fuel consumption. A steam-methane reformer reacts steam and methane over a catalyst to produce hydrogen, carbon monoxide (CO) and carbon dioxide (CO2). The same reaction and control objectives are found in hydrogen plants and methanol plants. The steam-methane reformer package can be made generic, reducing costs and prices. No production manager in an ammonia plant would be satisfied operating at nameplate capacity. If the nameplate says 2,200 tons per day, he will push the plant to produce more, of course. The limit is some constraint in the process—ambient conditions, capacity, temperatures, etc. To operate at the higher-than-nameplate rate often requires adjustment to the control package used on the steam-methane reformer. An example, in hot climates, cooling water can be a constraint for an ammonia plant. Cooling water is used in the CO2 removal system. Any oxygen-containing molecule (CO, CO2, H2O) will poison the catalyst used to produce ammonia so the goal is to make sure that we minimize the amount of these poisons in the feed to the reactor. CO is converted to CO2 in the shift-reactor section then the combined CO2 is removed in the CO2 removal system. Any CO or CO2 that slips through is handled by the methanol section. In the methanator, the reaction used in the reformer to produce hydrogen is reversed, converting hydrogen and CO2 to methane. When there is not enough cooling water, much more CO2 slips through and the methanator uses a lot of hydrogen to make methane. In the reformer, we are pushing to limits to maximize the amount of methane converted to hydrogen by firing harder. In the methanol, we then produce more methane by consuming hydrogen. The rest is wasted energy and a reformer being pushed to limits unnecessarily. The solution is to let the reformer “know about” the methanator problem. The reaction making hydrogen in the reformer is endothermic (requires heat) while the reaction in the methanator is exothermic (produces heat) . By measuring the temperature rise across the methanator, we can get an idea of how much CO2 is being converted into methane. Adding this value (methanator delta-T) to the reformer package’s constraints adjusts the reformer to compensate for the efficiency problem of making hydrogen at one end of the plant and reversing the reaction at the other end of the plant. This is not a solution that is necessary in many ammonia plants (and not needed at all in hydrogen and methanol plants), so, making it part of the steam-methane reformer package is not really an option. Being able to easily modify the advanced control to handle new constraints and problems in the ammonia plant is the solution. In packages like multivariable controller in DeltaV (used for the steam-methane reformer package), the configuration and testing tools are easily accessible to allow the particular ammonia plant to adjust to the particular problems it faces. Process improvement and optimization consultants can help you find opportunities to improve energy efficiency, reliability and the overall availability of your ammonia production process. From Jim: You can also connect and interact with other advanced control experts in the Improve & Modernize and DeltaV groups in the Emerson Exchange 365 community. Related Posts Solving Thermal Oxidizer Interacting Loops Optimizing Delayed Coker Operations with Advanced Process Control Flexible Operations for Changing Ethane Market Conditions Divided Wall Column MPC Control with Wireless Instrumentation Freely Available Learning Tools for New Process Automation Professionals Adjusting Model Predictive Controller Response The post Optimizing the Ammonia Production Process appeared first on the Emerson Process Experts blog.
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Blog Post: Optimizing the Ammonia Production Process
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Blog Post: Optimizing the Ammonia Production Process
James Gremillion Author: James Gremillion One of the earliest applications of “computer control”, a now archaic term, on an ammonia plant was done in 1969 by Weissenfelder and Shah of Borden Chemical and IBM respectively. They were able to implement advanced control schemes in a computer that had proven to be too difficult to do in the pneumatic and electronic controllers of the time. Ammonia production increased, costs went down and the plant operators had better information to make decisions. I followed A.J. Weissenfelder at Borden Chemical in 1977 and one of the first things I found was that it was so much easier to modify the advanced control schemes on the computer than trying to change the configuration of board instruments. Modifications that were required because of plant changes, modernizations, etc. could be, and were, quickly implemented. Today we implement control schemes very similar to what Weissenfelder and Shah did but with vastly improved tools that have made the control schemes even easier to implement and much easier to modify. Further, many control system suppliers and consultants have packaged ammonia control schemes to allow proven solutions to be implemented very quickly. By Mbeychok , Ammonia Synthesis Diagram , CC BY-SA 3.0 The packages for the steam-methane reformer, for example, have the same control objectives as the early computer control schemes—maximize throughput, reduce methane leakage to a minimum and minimize fuel consumption. A steam-methane reformer reacts steam and methane over a catalyst to produce hydrogen, carbon monoxide (CO) and carbon dioxide (CO2). The same reaction and control objectives are found in hydrogen plants and methanol plants. The steam-methane reformer package can be made generic, reducing costs and prices. No production manager in an ammonia plant would be satisfied operating at nameplate capacity. If the nameplate says 2,200 tons per day, he will push the plant to produce more, of course. The limit is some constraint in the process—ambient conditions, capacity, temperatures, etc. To operate at the higher-than-nameplate rate often requires adjustment to the control package used on the steam-methane reformer. An example, in hot climates, cooling water can be a constraint for an ammonia plant. Cooling water is used in the CO2 removal system. Any oxygen-containing molecule (CO, CO2, H2O) will poison the catalyst used to produce ammonia so the goal is to make sure that we minimize the amount of these poisons in the feed to the reactor. CO is converted to CO2 in the shift-reactor section then the combined CO2 is removed in the CO2 removal system. Any CO or CO2 that slips through is handled by the methanol section. In the methanator, the reaction used in the reformer to produce hydrogen is reversed, converting hydrogen and CO2 to methane. When there is not enough cooling water, much more CO2 slips through and the methanator uses a lot of hydrogen to make methane. In the reformer, we are pushing to limits to maximize the amount of methane converted to hydrogen by firing harder. In the methanol, we then produce more methane by consuming hydrogen. The rest is wasted energy and a reformer being pushed to limits unnecessarily. The solution is to let the reformer “know about” the methanator problem. The reaction making hydrogen in the reformer is endothermic (requires heat) while the reaction in the methanator is exothermic (produces heat) . By measuring the temperature rise across the methanator, we can get an idea of how much CO2 is being converted into methane. Adding this value (methanator delta-T) to the reformer package’s constraints adjusts the reformer to compensate for the efficiency problem of making hydrogen at one end of the plant and reversing the reaction at the other end of the plant. This is not a solution that is necessary in many ammonia plants (and not needed at all in hydrogen and methanol plants), so, making it part of the steam-methane reformer package is not really an option. Being able to easily modify the advanced control to handle new constraints and problems in the ammonia plant is the solution. In packages like multivariable controller in DeltaV (used for the steam-methane reformer package), the configuration and testing tools are easily accessible to allow the particular ammonia plant to adjust to the particular problems it faces. Process improvement and optimization consultants can help you find opportunities to improve energy efficiency, reliability and the overall availability of your ammonia production process. From Jim: You can also connect and interact with other advanced control experts in the Improve & Modernize and DeltaV groups in the Emerson Exchange 365 community. Related Posts Solving Thermal Oxidizer Interacting Loops Optimizing Delayed Coker Operations with Advanced Process Control Flexible Operations for Changing Ethane Market Conditions Divided Wall Column MPC Control with Wireless Instrumentation Freely Available Learning Tools for New Process Automation Professionals Adjusting Model Predictive Controller Response The post Optimizing the Ammonia Production Process appeared first on the Emerson Process Experts blog.
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Forum Post: You know you're a Momgineer when...
I'm sure a lot of you "momgineers" out there would appreciate this: http://alltogether.swe.org/2016/07/you-know-youre-a-momgineer-when/
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Forum Post: RE: Emerson Exchange America’s 2016 Event – Recommended Modernization and Migration Related Sessions to Attend
Hi Scott~ In this case, I think the image is simply too detailed to render correctly at a larger size within the platform. I had our designer create a jpg and re-uploaded and it still doesn’t work. Bummer. Let me look into what might work in the future- Ill contact our platform provider- I have a feeling they will tell us to build a table using the tool bar. In the interim, I provided instructions to double click on the image- which DOES render clearly when doing so. Thanks for your patience… Rachelle
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Forum Post: RE: I can not open delta v explorer
Do u have last backup?? Area wise.. With power up folder.. U need to create the new database.. Nd then once it's created.. U can re select the original data base... I had dis problem some 2 year ago.. Nd did d same.. Eventually it worked.. Back up I asked is if in case it did not run import fhx files area wise... Controller will not be downloaded... But I experienced dis thing once.. Nd after that it's working..
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Forum Post: RE: DeltaV Control Studio "Read Only"
Well this is something u did not mention earlier.. But I also change class modules limit or at times expressions.. Never converted to class module.. Once I did it to change the logic but never had dis problem of data u mentioned earlier.
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Forum Post: RE: I can not open delta v explorer
dear Friend create new database ...and dere must be some back up ..if not then for future you must take back every month put this in routine
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Forum Post: RE: Path/File Access Error
Dear Youssef.El-Bahtimy Thank you for your reply, I just reinstall everything with last backup importing in all works Fi9 now :)
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Forum Post: RE: Shattering the Glass Ceiling - Why this year's momentous election gives us ALL a reason to be inspired & invigorated
I myself was the first Woman Officer Recruiter in the Marine Corps. Wonder how many glass ceiling stories we have in Emerson? Would be interesting to hear! Honored to work with so many smart, effective, driven women. Kerry Nedic T +1 847 268 6460 | M +1 847 770 5667 Kerry.Nedic@emerson.com
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Forum Post: RE: Shattering the Glass Ceiling - Why this year's momentous election gives us ALL a reason to be inspired & invigorated
Kudos on a stellar accomplishment, Kerry Nedic . I'd love learn about more stories from Emerson women, I could even turn it into a blog post! :)
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Comment on I am a woman in STEM. But, it hasn’t always been easy.
Thanks for sharing your story Rossella. While we may have made some progress in equality, we still have work to be done. It is vital to the world that we encourage and support young women who are interested in STEM. Innovation is driven by diversity of ideas and perspectives. Congratulations on your hard-earned success and thank you for your positivity.
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Forum Post: The bar has just been set. Arianna Huffington to launch new start up at 66...
66-years-old & launching a new start-up. Choosing not to juggle 2 companies- even when one is your namesake. I could go on, but for me, admiration is an understatement. Arianna Huffington is an inspiration for women in any industry who work to shatter expectations and ceilings. www.wsj.com/.../arianna-huffington-to-leave-the-huffington-post-1470915169
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Forum Post: RE: Batch Unit Acquire Problem
When we encounter this issue we just open up the unit that owns the equipment in control studio online. Then drill into a running phase and set the REQUEST parameter to the correct code. If using an indirect code then set REQDATA1 first, then the REQUEST parameter. This can be done when the phase is HELD or RUNNING. When running just make sure the code is not going to be setting the REQUEST parameter anytime soon.
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Forum Post: RE: Configuration of ALM_FLOOD_SUP module in DeltaV
Kim, thanks a lot for your help here in clarifying my doubts, it has helped immensely. I will give it a try and get back to you in case the advice does not meet my needs. Thanks again, Yash
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Forum Post: Calculation of TSS on DeltaV Insight Models Viewing.
Hi everyone, I would like to know how the TSS calculation is made in DeltaV Insight which is reported in Models Viewing section. I know that TSS calculation, i.e. for FOPDT process response should be calculated as: (5 x Time Constant) + DT However, for one of my control loops DeltaV Insight reports the following figures in Models Viewing: a. TC= 356.2 sec, DT= 91.8 sec and TSS= 1055 sec Doing the manual calculation, I obtain TSS= 1872.8 sec = (5 x 356.2) + 91.8 b. TC= 316.6 sec, DT= 94.1 sec and TSS= 960 sec Doing the manual calculation, I obtain TSS= 1677.1 sec = (5 x 316.6) + 94.1 Could any one help me, in order to understand how DV Insight makes TSS calculations and why is so much difference in comparison with manual calculations? Best Regards.
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Forum Post: New 3582 Positioner tutorial videos now available
Modern digital valve controllers are typically the first choice positioner for new control valves. However, there is still a large installed base of the Fisher 3582 traditional pneumatic positioner. As the workforce ages the knowledge & skills required to setup these devices gets lost so it's good to have visual aids to correctly mount and set them up. With this in mind 3 videos have been produced to supplement the instruction manual and help users do just this. Each video is around 5 minutes in length and walks users through the necessary steps. So whether you need to setup a 3582 positioner on your plant or want to educate your workforce on how technology has evolved, these videos are a great asset. 3582 Positioner Mounting 3582 Positioner Calibration – Beam Alignment 3582 Positioner Calibration – Zero and Span
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Forum Post: RE: Calculation of TSS on DeltaV Insight Models Viewing.
it should be multiplied by 3 based on this "Typical estimates are: (3 × First Order Time Constant + Dead Time) or (4 × Dead Time), whichever is greater for the slowest responding input/output pair"
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Forum Post: RE: Path/File Access Error
I'm sorry you had to re-install everything, usually workstation configuration by itself can correct these types of setup problems, but I'm glad you got everything running.
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Comment on Retirement, Fond Memories
Thank you for all of your amazing blog posts and for aiding others in the DeltaV forum. Terry Blevins , your contributions to the Emerson Exchange 365 community over the years will remain invaluable. Thank you for being a mentor, resource and inspiration to so many young engineers. We hope you will continue to pop in from time to time and offer others your uniquely, Terry Blevins, insights. Cheers!
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Forum Post: DC grounding for 2-wide power/controller carriers in a redundant controller node .
The M-Series Hardware pdf (Documentation Library) indicates that the 2-Wide power/controller carrier DC reference ground needs to be wired to the Isolated Common Ground Reference within cabinet. However, I couldn't find any documentation whether both 2-wide carriers, in a node with redundant controllers, need to be grounded the same way.
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