Emerson Process Experts

ModelingAndControl.com's Greg McMillan and Solutia's Mark Sowell will be presenting at the upcoming ISA 54th International Instrumentation Symposium. Their paper, Advances in pH Modeling and Control, describes the use of embedded simulation, coined "Virtual Plant" and model predictive control to improve the control of pH levels in a plant waste water treatment application.

The authors begin by describing the challenge of pH control:

The pH electrode offers by far the greatest sensitivity and rangeability of any industrial process measurement in terms of the measurement of concentration (hydrogen ions). To realize the full potential of this opportunity requires extraordinary performance of mixing equipment, control valves, reagent delivery systems, flow meters, control system design, and controller tuning.

The virtual plant is described:

A virtual plant can be used to sort out fact from fiction important for insuring performance and reducing capital and operating costs. The virtual plant consists of a download of the actual control system configurations and displays, embedded advanced control tools, and a dynamic process model running on personal computer...

The articles details the control strategy used:

We developed and prototyped model predictive controllers (MPC) to replace the fuzzy logic control system. MPC-1 adjusted the 1st stage pH set point to keep the second stage reagent valve at a minimum position for good response and reliability. MPC-2 trimmed the 2nd stage set point to keep the pH in the tank at an optimum pH.

The authors describe the interaction of the virtual plant with the real plant. They write:

In order to study and improve performance of the control system and the fidelity of the process model for actual process conditions, we put the virtual plant in a read-only mode online running real time. A simple interface module was configured that used object link[ing and] embedding for process control (OPC) to read indicated waste flows, controller set points, and controller modes from the actual plant.

If you are battling pH control in a waste water treatment application, you'll want to give this paper a read. You might also want to get your hands on one of Greg's books, Advanced pH Measurement and Control, if pH control is currently vexing you.

Update: Greg wrote me that the presentation went well and the room could have been bigger to hold all the folks interested in hearing about this topic. He has done a slight revision on page 1 to better tie in the results to the general situation with pH systems. This version is now posted on the original hyperlink above.

Tags: pH modeling | pH control | virtual plant | process simulation | waste water treatment |

April 21, 2008 in Control Strategies, in Process Optimization, in Regulatory Compliance, in pH Control | Comments (0)

My spy utility, WatchThatPage, alerted me to another good article, this time on the Fisher control valves and regulators area of the Emerson website. The article, Getting ready for the nuclear renaissance, from the April issue of Valve World magazine, features Bill Fitzgerald, director of the Fisher Valves nuclear business unit.

As more and more people around the world climb the economic ladder, the global demand for energy continues to grow. A nuclear power renaissance is underway, according to Bill driven by:

…issues like global warming and a desire for energy independence... It can never be the only solution, but it is a logical part of the solution.

Bill describes his team tracking forty U.S. projects. He estimates two-thirds of these will actually be built. The first ones may come on-line as soon as 2015. Bill describes the large engineering firms as well as the U.S. Nuclear Regulatory Commission (NRC) staffing up anticipating the work required to completely design, build and commission the first wave of these plants over the next seven years. This expected growth is by no means limited to the U.S.

As part of this process, the engineering firms' procurement people need to identify and begin to purchase the long-lead items like reactor vessels, which may take three years from order to delivery. Control valves also fall into this long-lead item category. As Bill explains:

…control valves have long lead times because the ASME has just issued new qualification requirements. So to use a valve in a given safety related application will probably require 18 months of qualification testing. We also have to factor in ever-tighter seismic requirements. Then materials procurement, machining, assembly and testing will probably take an additional 9-18 months, depending on valve type. So, we believe that if we get an order today for a nuclear grade valve it could take as long as three years to actually deliver it to the end user.

And Bill notes that these valves are used in safety critical areas. Not having them will delay the startup of the plant. Based upon this expected global increase in nuclear power plants, Emerson and other automation suppliers are increasing their capabilities to meet this demand.

Technology has changed greatly since these types of plants were built in the U.S. a generation ago. Bill describes digital technologies like Foundation fieldbus, which can be used in the balance of plant applications to provide better control and diagnostic information. Devices like digital valve controllers have completed Electric Power Research Institute (EPRI)-certification for use in this demanding application.

As energy producers seek ways to meet the increasing global energy demand, these preparatory activities are critical to meet challenging project schedules.

Update: I was just pointed to a great Béla Lipták article, The Third Industrial Revolution by a member of our DeltaV Twitter community. Béla describes the post fossil fuel world based on solar power and the role of process automation. It's well worth your read and I look forward to his book due out in August.

Tags: nuclear power | control valve | safety valve | digital valve controller | valve regulator | Foundation fieldbus | NRC | ASME | EPRI |

April 16, 2008 in Foundation Fieldbus, in Plant Equipment, in Power, in Regulatory Compliance, in Safety | Comments (0)

A colleague recently pointed me to a Manufacturing Business Technology article, Red alert: Increase in process automation heightens need for safety-related systems. The article points to a recent Frost & Sullivan study which predicts the market for safety-related systems used by process manufacturers will more than double from 2006.

Quoting from the account of this research report:

It says users will welcome systems that address the underlying challenge of minimizing the trade off between process uptime and process safety. In addition, users will favor vendors that have significant technical experience in installing complex integrated safety solutions that monitor safety and non-safety functions while reducing the costly channels of diversified communication.

Over the past several years of blogging, I've discussed safety instrumented systems and the associated global standards, IEC 61508 and IEC 61511 on numerous occasions. Newer architectures like Emerson's smart SIS incorporate digital communications so that the complete safety instrumented function (SIF) can be continuously diagnosed to help the function perform when it should and not when it shouldn't.

Rather than being prescriptive and instructing process manufacturers what to do, the safety standards are performance-based. IEC 61511 allows you to investigate the alternative solutions for the right safety instrumented function for the safety integrity level (SIL). This means that more engineering work may be required to investigate these alternatives to find the best solution.

I think this where the "technical experience" part of the quote from above comes in. Emerson's Len Laskowski said it best in an earlier post:

This is great news for the engineering community because they get to do the engineering. However the bad news is they must do the engineering.

As process manufacturers address their risk-mitigation strategies and comply with the IEC 61511 standard, they will continue to work closely with those that can provide the technical expertise required throughout the safety lifecycle, from front end engineering and design to ongoing system maintenance.

Tags: IEC 61511 | IEC 61508 | SIS | safety instrumented system | FEED | front end engineering design |

January 7, 2008 in Project Services, in Regulatory Compliance, in Safety | Comments (0)

Emerson technologist and ModelingAndControl.com blogger, Greg McMillan, coauthors with Solutia's Mark Sowell an article, Virtual Control of Real PH in the November issue of Control magazine. The wonderful thing about Greg's writing is that it seems to always include experienced-based rules of thumb, a lack of sugarcoating the facts, and large amounts of humor. You can see what I mean on the Process Control Insights area where we've been collecting his works.

In this article, the authors waste no time in mentioning why we should be interested in reading the article. Most plants have pH control applications, even if in their waste-treatment areas. These areas usually have environmental compliance issues and for applications like crystallizers, fermenters, reactors, and strippers, pH control is critical.

My example of Greg not sugarcoating the facts is:

While we tend to focus on the configuration of the DCS, achieving the full potential of the pH measurement requires exceptional attention to every aspect of the system design. Deficiencies in the equipment, piping, valves or sensor selection or installation can cause the system to fail miserably.

This advice alone may save someone loads of troubleshooting time by first looking at the field equipment and installation before fiddling with the automation system's configuration and tuning.

He's also very good at simplifying the approach to pH control problem solving by helping the reader form a quick mental picture:

The name of the game with pH is to minimize the loop dead time to minimize the excursion along the highly nonlinear titration curve.

The solution described in the article is to use a virtual plant—a dynamic simulation of the waste-treatment system—based on a first-principle dynamic model of the pH system and control system configuration. These all run in the same PC. Dynamic simulations can be quite complex but here's where Greg's rules of thumb based on his experience come in. The key is to focus on simplification and attention to the details that really matter. An example of a rule of thumb:

For pH modeling for process control of environmental systems, about 20 acids and bases cover about 90% of the applications. The physical properties requirements are much less (just molecular weight, density and dissociation constants of each acid and base). The waste treatment systems are normally dilute enough so that activity coefficients are not needed.

They used the virtual plant to see if the existing fuzzy logic control could be replaced with a straightforward model predictive control (MPC) strategy. You'll have to read the article to see the full approach but the bottom line was that:

The MPC did a much better than expected job of chasing the acid concentration… We confirmed later that the production unit that was the source of most of the strong acid was having issues. A comparison of the virtual plant and actual plant control valve positions and pH response revealed there was no flow going through one of the second-stage reagent valves. The problem cleared a day after a phone call.

I had to wrap up this post with an example of Greg's ever-present humor that engineers can appreciate:

It takes more and more interesting opportunities to get weathered engineers excited. However, the almost limitless opportunities to explore advanced control ideas make us downright tingly.

If you've been fighting pH control, the article is well worth it as is the "Extra-Credit Reading" they cite.

Tags: pH control | pH measurement | virtual control | virtual plant |

November 29, 2007 in Education, in Regulatory Compliance, in pH Control | Comments (0)

In an earlier post, I discussed maintaining compliance of hazardous area certified equipment, from a paper given by Emerson safety consultant, Bob Baker.

At the recent AIChE Spring National Meeting Process Plant Safety Symposium, Bob gave an updated paper, Safety & Regulatory Compliance of Reconditioned Equipment (presentation).

He sums up the pressures that process manufacturers face:

Responding to challenges of seemingly unending reductions in capital and maintenance budgets, the process industry has increasingly turned toward the purchase of lower cost, recycled equipment including salvaged control valves and instrumentation.

The market for salvaged and reconditioned control valves expanded from onshore and offshore oil and gas producers in the early 1990s to onshore chemical, petrochemical and refiners today due in large part to declining maintenance budgets and financial pressure on small, locally engineered capital projects.

Unless appropriate equipment purchase specifications are specified and followed, exposure to potentially significant safety risks may occur when using salvaged, new-surplus, refurbished, or remanufactured equipment (considered "reconditioned" equipment):

Although it equipment may be acceptable from a functional perspective, depending on equipment age, repair history, application severity and other factors, such "reconditioned" equipment may be out of compliance with safety standards, or with manufacturer's specifications as originally designed to applicable industry codes, for safe use in hazardous locations.

One of the U.S. Occupational Health and Safety Administration (OSHA)-accredited Nationally Recognized Testing Laboratory (NRTL) is FM Approvals. The paper notes that FM Approvals' position for reconditioned and new-surplus instruments for use in hazardous locations:

It is FM Approvals' position that only the original manufacturer of the Approved product or an FM Approved remanufacturer whose facilities are part of the FM Approvals follow-up audit program, can remanufacture a product and reissue the FM Approvals certification mark. Any suggestion, practice or inference to the contrary is wrong and must cease… Any salvaged, remanufactured or new surplus electrical instrument cannot be labeled or relabeled as FM Approved for use in a classified hazardous location unless the refurbishing/new surplus supplier entity is audited and approved by FM Approvals, LLC, for that specific type of instrument.

FM Approvals presented the issues, challenges, and its position at several safety symposiums in late 2006 and early 2007.

Bob offers this recommendation for process manufacturers:

Vendor qualification and technical awareness is critical, requiring initial education of all plant personnel associated with the specification, purchase, inspection or repair of reconditioned and new-surplus equipment. Further, ever-changing organizational structure and new personnel requires a sustained education program, including ongoing emphasis at safety meetings. End user issuance of specific corporate policy and guidance could be an effective method to appropriately emphasize and establish requirements for purchasing reconditioned equipment.

Regulatory organizations such as OSHA and EPA typically put the burden of sustaining compliance to safety and regulatory requirements on the end user.

If you are using or considering using "reconditioned" instrumentation in hazardous locations or "reconditioned" control valves in applications within your plant's Process Safety Management (PSM) program, make sure to read the entire paper. Bob provides suggestions for vendor qualification requirements, suggests work processes, and describes the applicable standards.

Tags: AIChE | reconditioned | remanufactured | salvaged equipment | new-surplus | control valve | instrumentation |

May 15, 2007 in Asset Optimization, in Regulatory Compliance | Comments (0)

In a recent Pharmaceutical Processing magazine article, PAT Searches for its Identity, author Bikash Chatterjee discusses the seemingly slow pace of Process Analytical Technology (PAT) implementations. The article states:

What the FDA has provided is a bold chance for our industry—long mired in historical inefficiencies and product failure—to reinvent and improve existing processes for superior cycle-time, consistency and yield.

Given the change in regulatory climate the article questions why we haven't seen a glut of PAT applications to help achieve better operational results. The author points to challenges in the details to implement. Also the traditional emphasis on product and compliance orientation needs to shift as the article states:

…toward an understanding of critical processes to achieve the significant PAT benefits that have worked so well in other sectors.

Given the complexity of this undertaking the author suggests going forward with an approach like Six Sigma as an operational excellence project management framework.

I caught up with Michalle Adkins, a consultant in Emerson's Life Sciences Industry Center, whom you may recall from an earlier post on five strategies for mitigating project risk. She agrees with the author that a PAT initiative should be managed as part of an overall Operational Excellence program. This is because more structure and process can be provided to the initiative.

Michalle believes that by using the Six Sigma methodology, the right tools can be applied at the right time for evaluating, managing, and implementing PAT projects.  The Six Sigma structure of define, measure, analyze, improve, control provides the structure for managing the PAT initiative. 

It's interesting to note that some of the same tools in the Six Sigma toolbox are already inherently part of PAT such as design of experiments (DOE), statistical process analysis, and methods development. These are all very much related in terms of the types of statistical tools that are used.

Given that the PAT guidelines are still relatively new, pharmaceutical and biotech manufacturers are recognizing that the proven Six Sigma tools along with the analytical tools already used for methods development can help organize the PAT process and move these initiatives forward. It will be interesting to see how these PAT implementations begin to accelerate in the coming years as structured methodologies are applied.

Tags: Process Analytical Technology | PAT | Pharmaceutical | Biotech | Life Sciences | operational excellence | six sigma |

March 6, 2007 in Life Sciences, in Process Optimization, in Regulatory Compliance | Comments (0)

OK, you've done all the engineering, installation and commissioning and have field electrical and electronic equipment that is certified for the hazardous location in which it operates. In North America, this equipment has been tested and approved to appropriate codes and standards by OSHA-accredited NRTLs (Nationally Recognized Testing Laboratories) like FM Approvals, UL, CSA, and MetLabs to name a few. Other countries may have similar requirements through entities such as PTB of Germany, LCIE of France, KEMA of the Netherlands, and UC (formerly UCIEE) of Brazil.

So what about the certification if the equipment has been salvaged from a plant that has been shut down, and then refurbished, reconditioned, or remanufactured and resold? Or what about equipment that is resold as “new surplus” or after installed equipment has been repaired?

Bob Baker, a Safety Consultant to Emerson Process Management presented with FM Approvals' Cheryl A. Gagliardi at the recent Mary Kay O'Connor Process Safety Center 2006 International Symposium. Their presentation, Maintaining Certification Compliance of Equipment Used in Hazardous (Classified) Locations, discusses what happens (or should happen) should a device be changed in some way, even unknowingly.

When ownership transfer occurs, as in the case of equipment that has been resold as new surplus or after being salvaged, refurbished, remanufactured, or reconditioned, there typically is no historical awareness of whether or not a device has ever been “changed” in any manner by the prior owner, resulting in potential non-compliance. Such a “change” could have been as simple as touching up the threads of an explosion-proof device’s galled terminal box housing or cover, or it could be the use of non-OEM parts, the accidental scratching of a flame path surface or damage to a flame arrestor, etc. These same types of issues could also occur during the repair of a device even though it may never leave an original owner’s site.

The FM Approval mark is a statement of conformity that a product is in compliance with defined standards at the time the product leaves the manufacturing and/or repair facilities audited and approved by FM Approvals. Once the equipment is placed into use, continued compliance with the applicable codes and standards becomes the responsibility of the process manufacturer, i.e. the end user.

FM Approvals listed its definition of repair as “work performed to the unit that would bring it back to its original condition approved by FM Approvals, with repair including refurbished, remanufactured, reconditioned, salvaged, and new surplus.” FM Approvals also presented that process manufacturers have several choices when making repairs on equipment with hazardous area approval certifications including:

• Returning the equipment to an original equipment manufacturer (OEM) or any of its repair facilities that are approved and audited by FM Approvals. The OEM has the design control and knowledge of the FM Approvals certification requirements to return the equipment to its originally certified condition
• Having the equipment repaired by a third party facility that is approved and audited by FM Approvals in accordance with its repair standard 3606:1998 – Repair Service for Process Control Equipment Used in Hazardous (Classified) Locations
• Performing the repair in-house if the process manufacturer’s repair facility is similarly approved and audited by FM Approvals to its repair standard 3606.

FM Approvals recommended that its certification marks be removed from non-compliant equipment resulting when the repair work is done by a facility which is not audited and approved by FM Approvals. Since the burden is on the process manufacturer that the equipment is approved for the hazardous location in which it operates, the process manufacturer should insist that either:

• The repair (all types as noted above) be done by a facility that is audited and approved by FM Approvals to recertify the equipment (and prove it, by submitting FM Approvals documentation to the end user, that is specific to the brand and model)
• Have the FM Approvals certification mark removed if the facility is not an FM Approved repair facility.

Removing the certification mark or the entire nameplate should help eliminate confusion about a device’s NRTL approval status, and reduce the chance of inadvertent installation into a hazardous location that requires an NRTL approved device.

Bob recommends that process manufacturers develop corporate policies and guidance directing inspection, engineering, maintenance, and procurement to ensure the installation of compliant devices for their intended hazardous locations. He also recommends that stringent supplier qualifications be established to prevent introduction or re-introduction of non-compliant equipment, and that identification and abatement processes be developed for potentially non-compliant equipment already installed.

In summary, it is important that industry understand whether the purchase of products for use in hazardous locations, as defined by the National Electric Code and OSHA, can give rise to product safety and regulatory compliance issues.

Ms Gagliardi and Mr. Baker will again be presenting this topic on Thursday, January 25, 2007 at the Texas A&M Instrumentation Symposium (Jan 23-25).

Tags: hazardous area | equipment certification | FM Approvals | certification mark | process safety |

November 15, 2006 in Regulatory Compliance, in Safety | Comments (0) | Trackback (0)

Many process manufacturers have flow metering stations where ownership of incoming raw materials, intermediates, and/or outgoing products change. This custody transfer process is common with oil and gas producers, refiners, and chemical/petrochemical manufacturers.

Accuracy is critical since these measurements impact the bottom lines for both the seller and buyer. And, with the introduction in the U. S. of the Sarbanes-Oxley (SOX) Act of 2002, companies are required to put the controls in place to prove the accuracy of these measurements. Other countries have similar regulations requiring these documented proof-of-accuracy processes.

Robert Fallwell, a regional manager in Emerson’s Metco Services business, has written an excellent article, Sarbanes-Oxley audits: coming soon in the July issue of Control Engineering magazine.

Robert shares his expertise on how process manufacturers need to prepare for the SOX auditors. He boils it down to:

…they ask for proof that flow measurements are accurate, that you have procedures to ensure measurement accuracy, and that the plant’s operators, engineers, and production accountants have been trained in the correct procedures for the measurement control process.

If your business is impacted by SOX or similar regulations, you’ll want to incorporate some of the ideas presented in this article.

Tags: Sarbanes-Oxley | custody transfer | regulatory compliance | flow measurement |

August 8, 2006 in Chemical, in Custody Transfer, in Measurement, in Oil & Gas, in Refining, in Regulatory Compliance | Comments (0) | Trackback (0)