Emerson Process Experts

I use a service, WatchThatPage, to track changes to various pages around Emerson Process Management. It sends me an email when any page in a list of pages I have created has changed. I use this as one of my sources for the posts I create. This helps me keep track of changes in non-RSS enabled pages. For those who don't use RSS (really simple syndication), here's some resources on how it makes your information quest more efficient.

Late last week I received an email notifying me of a change to the Daniel liquid pipeline surge relief technical guide. I caught up with Dave Seiler to ask about this application and some of the challenges process manufacturers with high-pressure pipelines face. Pipeline operators and those with high-pressure pipelines are quite aware of the potential damage that can occur if a pressure surge occurs.

Dave noted that over-pressurization of a pipeline is commonly caused by sudden changes in liquid velocity. This may occur when a pump starts or stops or a valve opens or closes. When a pressure rise occurs above normal operating pressure, it's very important to analyze the rate of the pressure rise to determine the proper size and type of valve required.

Dave described line blockage as the most serious pipeline issue. To mitigate this condition, pipeline design includes valve interlocking logic and clear operating procedures. As noted in the technical guide:

…pressure is contained must have some form of pressure relief, which is often mandated and regulated by local authorities. The design of such systems is dependent on a complex range of factors including, but not limited to, the potential for pressure increases, the volumes which must be passed by the pressure relief equipment in operation and the capacity of the system to contain pressures.

This guide describes applications you may have in your facility. On application is a pilot operated pressure relief valve used for pump protection duty and for similar applications where pressure relief is required to maintain pressure at a given set point. Another application might have exceptionally fast response times that require gas-loaded systems. These are described:

The basic valve is the balanced piston design. Nitrogen gas is used to pressurize the valve piston to keep it in the closed position. The valve incorporates an integral oil reservoir mounted on the external surface of the cylinder head, which upon installation is partially filled with a light oil. Gas under pressure is applied to the reservoir.

Other applications described include surge relief valve closed position and open position. I found the pictures like this one help make the text easily understandable.

If you have high-pressure pipelines in your process, take a look at this guide and see how it might help you.

Tags: pipeline pressure | pressure vessel | gas pressure | gas tank | pressure relief valve | pipeline surge |

April 3, 2008 in Abnormal Situation Prevention, in Pipeline, in Plant Equipment | Comments (0)

In the world of process safety, technology continues to advance to assist process manufacturers in their IEC 61511 safety compliance efforts. I saw a recent press release on enhancements to the Fisher DVC6000 digital valve controller. The news was:

…enhancements include manual reset, a stored safety demand event log, pass / fail status after a partial stroke test, and third party certification to SIL3, SIF loop.

I asked Riyaz Ali, whom you may recall from earlier posts, to simplify what this all means for me. The stored safety demand event log he likened to an airplane black box recorder. If a process upset condition triggers a safety demand on a valve controlled by the DVC6000 SIS (operated by 4-20mA input signal), it in turn automatically triggers an event log to capture the data into non-volatile memory locally in the digital valve controller.

This log keeps pre- and post-event data of the operating conditions surrounding the safety demand event. Examples of the type of data stored away in this event log include: travel, travel setpoint, output pressure with time in seconds, graphical representation of data points and date and time stamp of the trigger event for regulatory compliance.

Riyaz also described for me the partial stoke testing reporting. It now will provide pass/fail status and a signature curve of the valve stem movement. These partial stroke tests periodically diagnose the SIS valve to help ensure its availability. Also, a specially designed built-in relay provides protection against spurious trips which improves overall process availability. Other information provided back to the AMS ValveLink software includes diagnostics on stick slip, shaft integrity and maximum and minimum torque values.

For the DVC6000 SIS, the Fisher team achieved third-party certification for compliance to the IEC 61508 international safety standard for use in a SIL 3 safety instrumented function. This means that process manufacturers can use the DVC6000 SIS as part of the safety instrumented function in the SIL 3 loops they identify as part of their risk assessment and risk mitigation strategy.

Having all these digital valve controllers keeping logs of what's going on especially around upset conditions can greatly assist root cause investigations and help avoid future abnormal situations. And the diagnostics coming from the partial stroke tests can help process manufacturers avoid these abnormal conditions in the first place.

Tags: process safety | IEC 61511 | IEC 61508 | digital valve controller | safety instrumented system | safety instrumented function | partial stroke test |

March 26, 2008 in Abnormal Situation Prevention, in Safety | Comments (0)

My RSS feeds pointed me to a great ChemicalProcessing.com article on batch manufacturing alarms. The article, Rethink batch-manufacturing alarm systems, was written by Joseph Alford.

He opens with provocative questions:

Do operators sing the praises of your plant's alarm system? No? Well, do they at least agree that generated alarms represent real abnormal situations requiring a response and that the automation/control system presents alarms in a timely, accurate and reliable way? No again? Well why not? Aren't operators the primary customers of your alarm system? Perhaps it's time for an alarm remediation project.

Many with continuous processes would agree that their alarm strategies implemented inside their automation systems need work. The complexity is amplified in batch processes because unique operating conditions are created within all of the numerous steps along the way.

The article boils down the crucial steps to take:

The key considerations in achieving effective alarm systems include defining objectives early in a project's life (i.e., in a plant's alarm philosophy or a system's functional requirements), adhering to the definition of an alarm, and implementing alarm-management best practices.

I ran this article by Todd Ham, a senior principal engineer in Emerson's Life Sciences industry organization. You may recall Todd from earlier posts.

Todd agrees completely that a successful alarm strategy begins in the functional requirements stage of a project. The project teams work with pharmaceutical and biotechnology manufacturers early on in a project to document their alarm requirements.

Todd stressed that a good strategy examines not only what conditions require an alarm—typically an adverse effect to personnel, product, or equipment—but also what is the desired response. Is alarm annunciation sufficient? Does this require a device interlock? Should this put the batch in hold? Does quality assurance (QA) need to be notified? This is called exception handling.

In a batch process, the requirements may differ based on the process step. For example, the alarm may be critical during processing, but not important during cleaning. Further, the alarm may only need to be monitored once the process is at steady state. In these scenarios, the control strategy developed by the project team will selectively enable/disable alarms at the appropriate point in the sequence.

Todd cautions that this is not a "one size fits all" exercise. The project team and manufacturer's staff must step through each process unit/system and ask a series of questions to arrive at a solution where alarms are both appropriate for a particular operating state and relevant for alerting operators to abnormal situations.

Todd agrees with the author that this work must be done up front, or the alarm flood, nuisance alarm scenario described in the article will be the result. You can't wait until the end of the project to think about alarm management. When you come right down to it, it's just as important as defining the control requirements for the project.

Tags: batch process | batch alarm | functional requirements | alarm management | alarm strategy |

February 29, 2008 in Abnormal Situation Prevention, in Alarm Management, in Project Services | Comments (0)

In the upcoming March issue of BioProcess International magazine, there is a great article by Emerson's Greg McMillan and Michael Boudreau, Broadley-James' Trish Benton, and the University of Texas at Austin's Yang Zang. The article, PAT Tools for Accelerated Process Development and Improvement, describes the collaborative effort between Emerson, Broadley-James, and UT, "…to examine and quantify the potential for faster optimization of batch operating points, process design, and cycle times." The specific objective of this collaboration:

…is to show that the impact of PAT can be maximized through the integration of dynamic simulation and multivariate analytics in a laboratory-optimized control system during product development.

Greg and Michael are putting many of the ideas they described in their book, New Directions in Bioprocess Modeling and Control: Maximizing Process Analytical Technology Benefits, into practice.

The authors outline the challenge for the 400 biotechnology medicines currently in development, which require overlapping and iterative stages for process development and commercialization. These stages include:

…cell line selection and development, media optimization, process conditions optimization and verification, scale-up, project definition, and plant design.

This team is working on beta tests using this new dynamic model and on-line data analytics and wants to make the results fully public to promote wide use and to advance these concepts and methodologies.

If you're like me and not in the biotechnology field, much of the article may get a little deep. I did glean a few tidbits you might find useful. By creating a dynamic model, one of the big benefits to the team is the ability to speed up the model by up to 1000 times real-time. Whether you're simulating the growth of mammalian cell lines or have another slow process, this can really help reduce trial and error time.

Another key is that the model, configuration, and tools can run in the "virtual plant" PC environment or can be downloaded to the automation system. With proper scale up factors:

…the embedded tools go readily from bench-top bioreactors to pilot plants and eventually industrial-scale bioreactors.

With the recognition by the FDA that quality cannot be tested into products, which led to the creation of the Process Analytical Technology (PAT) initiative, the authors discuss the role of analytics in their efforts.

Principal component analysis (PCA) and projection to latent structures (PLS) are two multivariate analysis techniques that can help analyze continuous and batch process operations. The authors' beta test is focusing on the on-line use of these analytical techniques where PLS detects deviations in quality parameters and PCA detects abnormal operations from measured and unmeasured disturbances.

Given the importance of new product development for pharmaceutical and biotechnology manufacturers, anything to reduce the overall development time and build in quality monitoring as prescribed in PAT should be a welcome addition.

Tags: bioprocess | biotechnology | pharmaceutical manufacturing | process analytical technology | PAT | multivariate analytics |

February 20, 2008 in Abnormal Situation Prevention, in Life Sciences, in Simulation, in Variability Management | Comments (0)

Emerson's Pete Sharpe, an advanced automation consultant, was recently interviewed for a magazine article on the subject of process manufacturers' aging workforce. Manufacturers primarily in North America and Western Europe are feeling this loss of experience due to retirement.

Pete indicated that the reoccurring theme he hears is the loss of deep process knowledge. This knowledge, possessed by experienced operators, maintenance technicians and senior automation engineers is knowing when something in the process is not quite right, like when a measurement reading looks off, or when the process behavior is not the same. As seasoned operators retire, manufacturers feel this loss of experience most during non-normal conditions like startup, shutdown, or emergency situations.

Problems take longer to diagnose and resolve which can lead to less stable, more dangerous conditions. A recent refinery accident is one example where the problem diagnosis did not occur soon enough. You don't ever hear about most incidents but they certainly cost manufacturers money and often result in close calls that don't actually shut down a unit.

Pete discussed a couple of things automation suppliers are doing to address these issues. The first is improved operator training simulators, which I have written about in earlier blog posts. In this environment, less experienced operators can be challenged with operating problem situations so that they can improve their ability to diagnose the process and respond more quickly to abnormal situations.

As technologies continue to advance, more diagnostic capabilities are available in smart field devices and other plant assets. These devices can provide early warning about their own health and about the surrounding process. These predictive capabilities improve the ability of the maintenance organization to prioritize and respond to critical equipment alerts. Emerson's Abnormal Situation Prevention (ASP) algorithm uses process statistical signature data to give less experienced operators more time to react to abnormal situations and more diagnostic information to point to the root cause of the abnormal situation.

The final advancements that help to close the experience gap are advanced control technologies. As the technology has gotten increasingly scalable and easier to deploy in control systems like the DeltaV system, more and more processes can be operated as units and not as collections of loops. These APC technologies operate a process unit within its equipment constraints, at its most economical point. The operator's role changes from constantly adjusting individual loops to setting targets and constraint limits. APC applications are especially useful for process units that are tricky to run by less experienced operators--where many of the loops interact with one another or the process is highly constrained.

These advancements help ease the learning curve for future operators, maintenance technicians and automation engineers. On the positive side, today's engineers and young operators are nearly all computer-literate, so they can make good use of the modern tools and work processes that come with today's control infrastructure. This computer-savvy generation is more likely to adapt to computer-based control systems and modern fieldbus architectures. In addition, automation suppliers like Emerson are helping to ease this knowledge gap by having people like Pete and the other advanced automation consultants available to work with process manufacturers.

Tags: process knowledge | plant operators | abnormal situation | simulation | advanced process control | APC |

June 19, 2007 in Abnormal Situation Prevention, in Education, in Operator Training | Comments (2)

In our continuing series of screencasts, I'm trying to give examples of how advanced diagnostics in Foundation fieldbus devices can be used in control strategies to avoid abnormal situations and potential losses in production.

Emerson's Rune Reppenhagen shows in this quick 2 minute, 47 second screencast, how an advanced model predictive control strategy in a DeltaV controller automatically recognizes a failure diagnostic in a temperature transmitter and switches the mode of control over to a manual state.

At the same time, this diagnostic alerts the operator of the situation, and the AMS Device Manager software shows the condition of the transmitter so it can be quickly repaired.

By using the advanced diagnostics from these intelligent field devices in the control and advanced control strategies, conditions which impact the availability and quality of the process can be avoided.

Tags: Foundation fieldbus | temperature transmitter | model predictive control | MPC | advanced process control | APC | screencast | diagnostics |

May 18, 2007 in Abnormal Situation Prevention, in Control Strategies, in Foundation Fieldbus, in Screencast | Comments (0)

Here is another in my series of screencasts, this time showing how an automation system uses predictive maintenance diagnostics to switchover a pump before it fails.

Emerson's DeltaV product manager, Randy Balentine, shows in this 2 minute, 43 second screencast a redundant pair of pump-motor trains. These pump-motor trains are being monitored with CSI 9210 Machinery Health Transmitters.

Randy shows a situation where one of the transmitters communicates excessive vibration via Foundation fieldbus digital communications to a DeltaV system. One of the DeltaV control modules receives the diagnostic alert, performs the logic to switchover to the backup pump-motor train, and notifies the operator of the problem so that it can be addressed.

By incorporating these predictive diagnostics into the control strategy, the switchover can happen before a failure causes a loss of production. Based on the severity of the diagnostic information reported by the smart Foundation fieldbus transmitter, the actions can range from notification of the operators to control actions performed by the control strategy.

Tags: Foundation fieldbus | digital busses | abnormal situation prevention | pump-motor | predictive diagnostics |

May 7, 2007 in Abnormal Situation Prevention, in Asset Optimization, in Foundation Fieldbus, in Screencast | Comments (0)

I had mentioned in an earlier post that short screencasts are a great way to quickly convery ideas in lieu of hundreds of words. One of Emerson's product application specialists, Rune Reppenhagen, graciously agreed to demonstrate how advanced diagnostics can be used in automation system control strategies.

Today's example shows how air in a fluid can impact Coriolis flow measurement and cause the automation system control strategy to falsely assume it needs to increase the speed of a pump to try to raise compensate for the low flow measurement. This situation called entrained air or slug flow causes the measurement on the coriolis meter to go to zero. The actual flow is OK but the problem is with the measurement.

Rune demonstates in this screencast (runtime: 4:51) how advanced diagnostics like those found in Micro Motion Elite mass flow and density meters can be configured in systems like the DeltaV system to read these diagnostics and take action in the control strategy to turn the loop to manual control for the operator and notify him of the cause of the situation.

This immediate recognition of a process problem and operator notification of the situation is one example of how advanced diagnostics and digital communications protocols like Foundation Fieldbus provide ways for process manufacturers to avoid losses in production, quality excursions, and abnormal situations which can impact the efficiency of the production process.

Tags: entrained air | slug flow | foundation fieldbus | screencast | abnormal situation | digital communications |

April 26, 2007 in Abnormal Situation Prevention, in Foundation Fieldbus, in Screencast | Comments (0)

Before the holidays, Dave Harrold wrote a post, A Wee Bit More About Safety Instrumented Systems, in his Dave @ AFAB Group blog. He describes his work with Dr. Angela Summers, founder/president of SIS-Tech Solutions on a guidelines book for the global IEC 61511 safety standards. Dave also referenced an SIS-related Q&A article Angela wrote for Flow Control magazine.

I forwarded the post and Flow Control article link to Riyaz Ali, whom you may recall from an earlier post. Riyaz wanted to add to the conversation and make three specific points in reference to the Flow Control article.

On the question regarding the use of digital valve positioners to perform partial testing and its relationship to the proof test interval, Riyaz agrees that the proof test is far more than a partial stroke test. The proof test can be performed on a final control element either on-line when a bypass valve exists or offline when the process is shutdown, such as during a plant turnaround. Many process manufacturers do not have large bypass valves and seek to extend the interval between plant turnarounds as long as possible. The on-line partial stroke testing provided by digital valve positioners can help extend the time between proof tests. They do not replace these tests. Riyaz points to a Control Engineering magazine article authored by Dr. Summers, Partial Stroke Testing of Safety Block Valves, in which she points out:

Also affecting the SIL is diagnostic coverage and testing intervals of partial-stroke testing to supplement full-stroke testing to reduce a block valve's PFD.

Being a mechanical item, testing of SIS "Final Control Element" offers challenges but at the same time represents a significant failure contributor to SIF loop. Partial stroke test by digital valve positioners not only allows "audit documentation" but also allows diagnostics health of valve, a key feature to improve reliability of SIF loop.

Riyaz did take exception to a statement in the article about throttling valves:

Positioner failures are the leading cause of control failure, so the positioner should not be used to actuate the valve in an SIS application when preventing events associated with a loss of control. Instead, a solenoid-operated valve should be used to independently close the control valve.

He notes that control valves are better geometrically designed with proper actuator and valve plug connection to reduce hysteresis, dead motion, sticktion, backlash etc., compare to shut down valves those are typically keyed shaft and mainly used for On and Off function. The main concern for shut down valves is stuck condition. If initial inertia force is broken during normal exercise of valve either through partial stroke test or by modulating through DCS signal, it is very likely that valve will be available during a safety demand, when required to bring the process to safe state.

His final point is on the question regarding smart positioners for partial stroke testing of smart valves. Positioners operated by air have been used in process control industries for years to improve performance of control loop. It is becoming rarer to come across a process loop not without positioners, especially where the application improved process variability. Based on its usage and benefits in process control, process manufacturers have started using them for Safety Instrumented Systems also. Riyaz agrees with Dr. Summers comment that positioners have smaller orifice but any thing larger than 8"-12" size valve, even otherwise a Quick Exhaust Valve or similar mechanical device will be used, if fast stroking speed is desired. Len Laskowski adds that the driving factor is process safety time. Many times larger valves do not need to close in one or two seconds, and in fact require a more controlled closure to avoid negative effects on process and utility equipment. It all hinges on the process safety time for each application.

Positioners by design are to bleed very small air to keep the air flowing as well keep pressure higher than atmospheric so as avoid any external atmospheric corrosive gas getting inside the housing. Also during partial stroke test positioners exhaust and fill the air, which makes its mechanical parts moving and avoid any build up.

Digital valve positioners allows partial stroke testing, while process is running and provides date and time stamp of test with capability to store and compare test results. Also, being a microprocessor based, these positioners allow remote testing and retrieval of data remotely. The main advantage is predictive maintenance by providing valve degradation analysis, which is important to critical valves in safety related systems. If by any chance valve is stuck, digital valve positioners are capable of providing alerts to operators to fix the problem.

Tags: IEC 61511 | digital valve positioner | proof test | partial stroke test |

January 2, 2007 in Abnormal Situation Prevention, in Safety | Comments (0) | Trackback (1)

From my days as a young systems engineer working on offshore oil & gas platforms in the Gulf of Mexico, I know that abnormal situations in our processes are something we all wish to avoid. A 1999 study by the ASM consortium estimated $10 billion USD in losses for U.S. process manufacturers due to abnormal situations. The question is how best to prevent these abnormal situations from occurring in the first place.

Emerson's Ravi Kant and Roger Pihlaja recently presented a paper, "Abnormal Situation Prevention (ASP) in Complex Systems" at the recent NPRA Q&A and Technology Forum.

In their presentation they stress that the potential severity and cost of an incident increases if timely corrective action is not taken. An example cited from a refinery abnormal situation is the failure of a butterfly valve. After going several hours without detection by the automation system or operations personnel, it caused the Cat Cracker (FCCU) to shut down. In a matter of minutes this caused the refinery to shutdown, resulting in more that $1 million USD per day in lost revenue.

Ravi and Roger explained how abnormal situation prevention (ASP) technology embedded in the sensors, actuations, and machinery health are closest to the process and have access to better information. This ASP technology can predict root causes of abnormal situations through high-frequency spectral and statistical data analysis within these smart devices. The main reason for doing this analysis closest to the process is that the sampling frequency is greater--22 samples per second, instead of 1 sample per second to 1 sample per minute typical at the automation system level.

Data analysis at this higher frequency can uncover process anomalies including drift, bias, excessive noise, process spikes, and plugged conditions. Some of the detection and prediction algorithms and techniques which are employed include: polynomial extensible regression, principal component analysis, statistical process control, decision trees, fuzzy logic, and neural networks.

They cited some specific ASP applications in refineries including early detection of catalyst losses, catalyst circulation issues, afterburn conditions, column and heater coking, temperature runaway, and acid levels outside optimal or safe levels. The key to detecting these process conditions is sharing this data analysis at from the field device level, up through the equipment level, up through the process unit level to the operators and plant maintenance staff. Digital communications technologies like Foundation fieldbus and HART provide the information path.

Roger also shared with me other high-frequency data dependant ASP applications in the process including:

• Plugged impulse line detection for DP flow transmitters
• Flame instability
• Stick/slip in FCC solids transfer lines
• Stirred tank vessel agitator diagnostics
• Continuous rotary drum vacuum filter diagnostics
• Fouling & DP level transmitter plugging in evaporators
• Detection of developing ASP issues like arching, bridging, & rat-holing in bulk solids storage vessels
• In-situ proof testing of emergency relief systems

Work continues to refine and extend these predictive ASP technologies to more smart field devices to increase the "eyes and ears" on the process in order to avoid the costs and losses associated with abnormal situations.

Tags: abnormal situation prevention | ASP | refining |

October 26, 2006 in Abnormal Situation Prevention, in Distillation Column, in Fired Heater, in Refining | Comments (0) | Trackback (0)

Recently an email came in that said Refineries and Petrochemicals specialist, Ravi Kant, and ASP Validation and Verification Engineer, Ahmad Hamad, in our Performance Technologies division, won the Fuels & Petrochemical’s Award for best paper (out of more than 80 papers) at the AIChE 2006 Spring National Meeting.

This was something I had to get my hands on and find out why, and extend hearty congratulations to Ahmad and Ravi. The predictive PlantWeb technologies developed by this team find their way into AMS Suite software products, Rosemount transmitters, and other Emerson smart field devices.

With many industries like refining and petrochemicals running near full capacity, abnormal situation prevention provides a method for early detection with problems in the process and provides an opportunity for timely corrective action--before down time, quality issues, or even safety issues occur.

The paper, Advances in Abnormal Situation Prevention in Refineries and Petrochemical Plants, looks at traditional ways of preventive maintenance and the drawbacks in performing unnecessary maintenance, sometimes requiring down time, and being unable to detect abnormal situations.

It also explores other techniques for abnormal situation management. These solutions use knowledge-based diagnostics with data drawn from the continuous historian to develop a multivariate model. The source data from the historian is typically very low frequency from once per second to once per minute. This approach fails to detect abnormal situation which can develop rapidly. It also often fails to find problems with machinery, devices, and transmitters in the process. An example might be a stuck valve.

Ahmad and Ravi describe how advances in microprocessor performance and digital communications like Foundation Fieldbus and HART make it possible to do high frequency diagnostics within smart field devices. Emerson Process Management has developed Abnormal Situation Prevention (ASP) blocks in smart field devices like Rosemount 3051s transmitter, which capture high frequency process data at 22 samples per second. The blocks perform statistical, frequency-based, auto-regression, wavelets and other diagnostic measures to try to discover problems in the process in their earliest stage. And automation systems like the DeltaV and Ovation systems can turn the most critical of these alerts from these ASP blocks into operator and maintenance alarms for corrective action to begin.

The paper describes for cases where this early detection can prevent abnormal situations from occurring. These include: coke detection in refineries, catalyst circulation in fluid catalytic cracking (FCC) units, maltrays detection in crude columns, and gas turbine abnormalities. These are but a few of the critical applications where abnormal situation prevention technology can be applied.

Like anything else, the closer you can get to the source of the abnormal situation, and the earlier you can identify it, the sooner you can mitigate or prevent the situation from occurring.

Tags: refining | petrochemicals | AIChE | statistical control | multivariate analysis | abnormal situation prevention | ASP |

May 2, 2006 in Abnormal Situation Prevention, in Refining | Comments (0) | Trackback (0)