Chemical

A few weeks ago, I relayed a story from Emerson's James Beall about a process of ongoing plant control performance improvements on which he's been working with a process manufacturer. He said he had another great story about an ethylene furnace optimization project. Not being the patient sort, I gave it a few weeks and called him yesterday.

For those not familiar with an ethylene (C₂H₄) production, the production section of the Wikipedia Ethylene page offers:

Ethylene is produced in the petrochemical industry by steam cracking. In this process, gaseous or light liquid hydrocarbons are heated to 750-950 °C, inducing numerous free radical reactions followed by immediate quench to stop these reactions. This process converts large hydrocarbons into smaller ones and introduces unsaturation. Ethylene is separated from the resulting complex mixture by repeated compression and distillation.

The ethylene furnaces provide the heat required for this reaction. James described the key control challenges as maintaining a constant severity target [conversion rate], maximizing the charge or feed rate, maintaining the proper incoming hydrocarbon/steam ratio, minimizing excessive air required in the furnace combustion chamber, and maintaining the furnace within its operating constraints. Given the multivariable nature and the interactions of operating objectives, model predictive control (MPC) was a great fit for this application.

James and the other process control consultants, many featured in this blog's process optimization category, have created a number of application solutions that combine subject matter expertise, process and advanced process control technology, services and training. These SmartProcess solutions are pre-engineered, have reusable, built-for-purpose templates, and control strategies. The SmartProcess Ethylene Furnace is one example, and the application used in this story.

James shared that the plant operators had to constantly adjust multiple furnace control loop setpoints to maintain the severity target, meet the target feed rate, minimize excess air, maintain equipment constraints, etc. The model predictive controller was ideal for addressing these interactions and setting the key operating objectives. The controlled variables included total charge, combined coil output temperature (COT), stack O2 emission, pass temperature differences, steam ratios, and severity target. The manipulated variables included pass flows, steam ratios, fuel demand, and air demand. Constraints included Oxygent, CO, fuel pressure, air capacity, firebox temperature, draft pressure, crossover tube temperatures, pass outlet temperatures and hydrocarbon feed valve positions. Finally, the disturbances included fuel BTU, heater inlet temperature and feed composition.

The conversion from individual PID loops to MPC took about two weeks per furnace. James noted that improvements learned on the later furnace control conversions were applied back to the earlier MPC controllers. Once the ethylene furnaces were optimized, the team benchmarked the performance and compared it with pre-project performance. They calculated a 70-80% deviation reduction from severity targets and an 87-88% standard deviation reduction in severities resulting in more stable operation. Hot spots in the tubes were reduced 50-90%, which reduced coke buildup which can provide increased run time before decoking.

Average severity increased 3-4% with 7-12 degrees lower COT, and stack O2 levels were reduced 0.23%, which reduced overall energy consumption. Finally, total furnace charge increase 8.4%, which increased the overall capacity.

The payback for the project costs on each furnace was less than 3 months! From the operators' point of view, the overall performance of the ethylene unit is more stable and the furnaces are capable of running longer between decoking operations. I imagine these results make James a popular person on his visits to the plant!

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I saw some startling facts in a presentation by Emerson's Pete Sharpe, whom you may recall from many process optimization-related posts. This week he visited The Automation Group (TAG) office in Houston, to discuss distillation and fired heater optimization. I was speaking with Aaron Crews who was able to catch this presentation. Aaron's expertise has also has been highlighted in several automation modernization and social media related posts.

Did you know that there are over 40,000 distillation columns in the U.S. alone? And that they consume 40-60% of the total energy in the chemical and refining industry. And that these distillation columns consume 19% of the total energy consumed by U.S. manufacturers. And finally, that these consume 6% of the total U.S. energy usage. If you drive along the Texas Gulf Coast and see all the refineries, petrochemical, and chemical complexes, it's not hard to accept these statistics.

I think it's safe to say that anything that can be done to improve the energy efficiency of these distillation columns will reduce operating costs, improve emissions, and lower the overall domestic need for energy. Pete noted that reducing energy consumption is one of the best ways that U.S. manufacturers can meet the Environmental Protection Agency (EPA) greenhouse gas reporting rules.

Pete and his team of refining and chemical consultants, work with process manufacturers to optimize the performance of their distillation processes. SmartProcess Distillation packages the team's subject matter expertise, couples it with Emerson products such as the DeltaV system with its embedded advanced process control, and provides planning, engineering, commissioning, and training support on these optimization projects.

For those not as close to the process of distillation, a distillation column separates components based on different boiling points. The column is made up of trays, and the temperatures of these trays usually reflect composition on that tray. These temperatures need be compensated for pressure.

From a control strategy perspective, in any column, you are trying to control a composition of the top product and the composition at the bottom of the column - simultaneously. The mental framework one follows is, "What comes in must go out." This translates into a material balance and energy balance. The material balance is represented by the fraction of the feed that goes overhead, or the overhead (OH) rate divided by the feed rate. The energy balance is represented by a reflux ratio, or the internal reflux flow rate divided by the feed rate. Dual composition control uses both the material and energy balance handles to simultaneously control both overhead and bottoms compositions. Since these are highly interactive, it typically requires a model predictive controller like PredictPro to accomplish closed loop control.

Aaron relayed a key point that Pete emphasized. As you approach 100% purity on either end of the column, the change in energy per change in purity increases dramatically, making high-purity columns prime targets for energy savings. Pete stressed that Advanced Process Control will almost always reduce the column variability, push to minimum reflux limits and allow operators to run closer to the specifications. This in turn results in improved product quality controls, less quality giveaway, lower specific energy consumption and less emissions. Good for profit, good for the environment.

Pete shared some typical results achieved in installing the SmartProcess Distillation application. For 1-2 weeks of engineering to design, install, and commission, plants have been able to achieve a 40-80% variability reduction, 5-10% throughput increase, 5-10% energy cost reduction, less off-spec / rework and improvements in safety and environmental metrics.

If you see opportunities to improve control on your distillation columns, it seems like the energy reductions and improved operations can fund it.

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A recent Wall Street Journal article, U.S. Expects Steady Climb in Energy Prices opens:

Energy prices are undergoing a long, slow march higher as major economies shake off the effects of last year's recession, the U.S. Energy Information Administration said Tuesday in its monthly outlook.

This outlook has many process manufacturers in energy-intensive industries again looking for opportunities to increase their energy efficiency. Emerson's Dr. Douglas C. White has written a great article, Save Energy through Automation, in the January 2010 edition of AIChE's Chemical Engineering Progress magazine.

Doug takes a reference Olefin plant with a naphtha feed that produces 500K tons/year of ethylene, total energy usage of 30MMBtu/ton ethylene, and total steam usage of 11MMBtu/ton ethylene. You can see the other process parameters on page 2 of the article.

He provides very specific energy saving examples and business result quantification based on the reference plant. I'll highlight only a few specific examples but you'll want to read the full 8-page article if energy efficiency improvements are part of your 2010 plans. Doug notes:

Advanced control and optimization systems can have a large impact on energy usage. However, their general functionality and energy impacts have been covered previously [Nasi, M. et al Experience with ethylene plant computer control, Hydrocarbon Processing, V62, N6, June, 1983, p. 74] and will not be discussed further here.

It's important to make sure the key plant variables are being measured accurately, "in terms of location, frequency, accuracy, and number." Deadtime can be introduced if the measurement device is physically located some distance away from a more appropriate location. Doug shares that this deadtime reduction can have a greater impact on loop performance than any tuning or algorithm change.

Many petrochemical plants measure fuel gas by volume instead of mass and density. If a plant has variations in fuel gas composition, flowmeters which measure mass and gas density will reduce the variability in cracking furnace combustion control. He cites an example naphtha plant:

...this improvement might be 0.2% in furnace efficiency, which is worth approximately $200,000/yr...

Market conditions, feedstock availability, furnace decoking, and process equipment availability impacts the load/throughput at which a plant operates. Effective anti-surge control on the cracked gas and refrigeration compressors is important since these units are major energy consumers within the plant. Doug writes:

The recycle valve needs to open very quickly and accurately to recirculate gas from the stage discharge to the suction. The ability to stably and safely operate the compressor closer to the surge limit saves energy, and the required operating constraint margin depends on the response characteristics of the anti-surge valve.

These anti-surge recycle valves can go from open to close and close to open in under two seconds. Doug quantifies:

If the plant is in low-throughput conditions 25% of the time, the value of the reduced recycle would be $125,000/yr for the reference plant.

Other energy saving examples Doug describes include stack gas CO measurements for improved combustion efficiency, key control loop dynamic analysis and tuning, and energy management and information systems (EMIS).

He closes the article with the importance of having a, "...structured program to assess, implement, and sustain energy savings achieved through automation..." This includes and energy study block diagram showing this structured approach to identify the top priorities.

There is a wealth of wisdom of practical ways that you can reduce the energy consumption of your process operations. Give the article a read if this imperative is part of your 2010 plans.

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Reconciling Mass and Energy Balances in an Ethylene Complex is the name of a presentation recently given by Emerson's Patrick Truesdale. The venue was the 2009 AIChE annual meeting in Nashville, Tennessee. Patrick is a senior consultant on the Industry Solutions team and has a wealth of experience in the refining and petrochemical industries.

Patrick began his presentation by identifying some of the challenges ethylene producers face, especially in mature plants found in North America, Latin America, and Europe. Plants (brownfield) built decades ago were typically sized around 300 KTA (kilo tons per annum). Today's newer, greenfield plants found mostly in the Asia Pacific, Middle East, and Africa world areas are typically larger than 1000 KTA.

With the run up in energy prices over the last several years, the older, brownfield plants were not instrumented with mass measurements to do mass and energy balances. Ethylene plants have also been focusing their capital expenditures to meet higher quality specifications, increase capacity, address new regulatory compliance, and process cheaper feedstocks. For many ethylene producers, the plant staff has been stretched and unable to focus on improving energy efficiency.

Patrick described one of the common key performance indicators (KPIs), loss opportunities. He defined the gain/loss as open inventory plus receipts minus shipments minus closing inventory. Receipts include the fuel consumed in the production process and shipments include the fuel produced by the process. These gains and losses can be accountable and unaccountable. Examples of accountable losses include what is flared and coke produced. Examples of unaccountable losses include leaks and theft.

Process energy usage is the largest controllable cost in most ethylene plants and requires a focused effort to improve this gain/loss KPI. Patrick outlined a process that begins with defining the process boundaries. It starts with the feeds, steam, and fuel gas to the fired heater as well as the distillation tower feeds, tops, and bottoms. Next, look at the cracked gas compressor turbo machinery, cryogenic distillation, and hydrogenation reactor. Temperature and pressure measurements around these boundaries provide the inputs for mass and energy balance calculations.

The second step is to identify custody transfer boundaries, which includes the raw material production and supply at the load port, the unload port at the ethylene complex, the load port for ethylene at the complex, and finally the unload port at the customer site. The bill of lading (BOL) combined with the custody transfer metering equipment measure transportation losses from each load to unload handoff.

The third step is to design mass and energy balances to account for losses and consumption in the production process. This includes measurements at the inventory holding tanks, tank-to-tank transfers, tank to unit transfers, and process nodes, as well as incoming receipts and outgoing shipments. Also, measurements need to be in place for any intercompany transfers of materials and energy.

The fourth is to survey the existing measurement systems. From Patrick's experience KPIs associated with mass loss are directly based on the quality of instrumentation and procedures: poor results--1.5-2.5% mass losses, average results--0.7-1.5% mass losses, good results--less than 0.5% mass losses, and pacesetters--less than 0.2% mass losses. Patrick notes there are a wide variety of flow measurement technologies from which to choose including Coriolis, differential pressure, magmeter, positive displacement, turbine, ultrasonic, and vortex. They each have strengths and weaknesses with respect to pressure drop, accuracy, required maintenance, slurry flow tolerance, viscosity tolerance, fluid conductivity, and process intrusiveness. In slides 18-22, Patrick provides some selection considerations.

Once the measurements are in place, the fifth step is to develop mass and energy balance models. Measurements should be validated, with errors detected and corrected to fix gross and bias errors. Random errors are reconciled through a simultaneous solution of the equations for:

• flows, inventories, and material transfers mass and volume balancing
• flows, inventories simple and multi-phase component balancing
• enthalpy, power, heat exchanger, and steam energy balancing

Patrick's final step is to define the business process to identify KPI reporting, the KPI dashboard, and the processes to implement continuous improvement. Having the metrics for when the plant is both operating smoothly and having problems helps provide the feedback to solve the operational issues more quickly and return to more energy efficient, smooth operations.

The KPIs for optimized energy usage and loss reduction are interrelated and the need to address grows with global competitive pressures, higher energy costs, and increasing regulations.

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At Emerson Exchange 2009, Lubrizol's Bob Wojewodka and Emerson's Terry Blevins presented, Benefits Achieved Using On-Line Data Analytics. Lubrizol and Emerson have worked together to develop on-line batch analytics as a beta test. The objective was to demonstrate on-line prediction of quality and economic parameters and evaluate different means of on-line fault detection and identification.

The intent was to document the benefits of this approach and learn from the test with data and usability feedback for product development of these batch analytics capabilities. Some of the challenges of applying online data analytics in a batch process are process holdups, access to lab data, variations in feedstock, varying operating conditions, concurrent batches, and assembly and organization of the data.

The foundation for this project was to form a multi-discipline, collaborative team that includes plant operations. They developed a workflow process to capture team input using an "input-process-output" data matrix to capture and explain the information required for the data analysis. It was important to integrate lab and truck shipment data by creating a workflow process with the plant's SAP enterprise planning system.

Calculated property estimation was performed on feed tank quality and other non-directly measured properties. The instrumentation was surveyed and loop tuning performed to improve process control. And, a formal training program was established so that everyone was knowledgeable about the new work processes.

For the data analytics, it was important to identify among a wide number of inputs and process variables how these variables relate and which ones have the greatest impact on product quality. These analytics could also predict the end of batch quality while the batch was running. The team had good correlation between the predicted end of batch, what the lab samples indicated, and what the end of batch time actually turned out to be.

The analytics were developed for two batch processes, where the output of the first fed the second process, as well as provided finished output.

Over the three-month period, a process fault was detected using the on-line analytics. A problem was identified a problem with the mass flow meter. This occurred during the initial training, so the operations team quickly embraced these analytics. The on-line analytics also discovered a problem with a hot oil heating system. They discovered the process with the first batch and estimated it would have taken weeks to find with traditional methods. This alone paid for the efforts by the collaborative team's time in this effort. The benefits have been seen from the operators through senior management.

In an earlier post, I mentioned a series of European Chemical Industry Wireless on-line webinars. I received a note from the team that the dates and topic focus for the rest of the 2009 webinars have been set. The intent is to show ways chemical manufacturers are using wireless technologies to improve the way they operate their plants. Squeezing out greater efficiencies is critical in these challenging economic times.

The next one, Doing More with Less with Wireless, is slated for September 14 at 3pm GMT (10am U.S. Eastern time). The Emerson European team, consisting of Peter Schellekens, Chris Hamlin, Manu Verschueren, and Ann Robin, identify several areas where wireless enables production, operations, maintenance and project functions to take a fundamentally different approach, which will have an immediate impact on business performance. The team will share examples that have been deployed by chemical manufacturers.

Although registration is not yet open for these future webinars, the rest of the year's schedule is:

Wireless in Projects - A Faster, Cheaper, Manageable Infrastructure - October 19, 3pm GMT

...demonstrate how wireless technologies have the potential to bring alignment between project organizations, with their emphasis on risk, cost and time, and the on-going systems and I/E engineering functions who are more concerned with consistency, sustainability and supportability.

Improving Production Performance with Wireless - November 16, 3pm GMT

...illustrate how wireless can change your approach to performance measurement and monitoring, and bring about significant improvements in productivity, yield and availability. At the same time, applying the same wireless technologies can also positively impact energy efficiency and personnel productivity.

Wireless - More Reliability, Less Maintenance - December 14, 3pm GMT

...illustrate how wireless technologies can reduce the frequency and severity of unplanned equipment failures, enable you to move away from reactive or periodic practices to truly predictive maintenance. Wireless enables you to properly understand the condition of field and process equipment in real-time. This means that you only take equipment out of service if and when it is really necessary, and because problems are identified early and accurately, the duration of any maintenance outage is minimized. Not only does this improve production rates, it also has a very significant impact on maintenance productivity.

Whether you're in the European region or not, or in an industry outside of chemical manufacturing, there just might be an application nugget or two that you can apply in your plant.

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I managed to get my hands on a great paper, Olefin Plant Energy Savings through Enhanced Automation, written by Emerson's Dr. Douglas C. White, whom you may recall from earlier posts. Doug is a principal consultant who leads the Process Improvement and Optimization Consulting team.

He presented this paper at the AIChE Spring National Meeting as part of the Ethylene Plant Technology - Energy Consumption and Optimization track. The abstract:

Energy is the single largest controllable cost for olefin plants and the recent rise in prices has caused most plants to look even more closely at their usage. Automation and advanced automation can significantly reduce usage across all areas of the plant. Some of these savings can be achieved with no investment, only changes in normal operating procedures. In other cases improvements to on-line analyses, measurements and control action are justified but generally require relatively modest investments. The management of the utilities at a major olefin site can be difficult with many daily operating decisions that must balance competing economic and production issues. Real time modeling of process and utility equipment and monitoring of the energy usage in plants permits allocation decisions to be made much more frequently and accurately, often resulting in substantial savings.

Doug describes the economics that Olefin producers face:

Olefin plants are large energy consumers with energy the largest variable operating cost after feedstocks. Using energy efficiently has been and remains a primary goal for olefin producers.

Natural gas is the marginal fuel consumed and its price has been a source of volatility over the past several years. Doug describes surveys where there is at least a 40% spread in energy usage between the most and least efficient plants. The source of this variation is due to the age and efficiency of the equipment and the heat integration.

Doug provides an energy investment opportunity matrix of high, medium, and low potential energy savings versus capital cost/time to implement. An example of a potentially high energy saving opportunity, but coming at a high capital cost is and integrated turbine. At the other end (low savings / low investment) are things like increased insulation and heat exchanger maintenance.

He describes two ways to reduce energy costs--either by reducing supply costs or reducing process energy demand. On the supply-cost side, the focus is to increase internal utility production efficiency and reduce external purchase costs. Advanced control and optimization on the furnaces, quench/fractionators, compressors, and distillation columns are a few examples cited on the process energy demand reduction side.

The paper describes areas to find energy savings. These include: control loop performance improvements, more accurate measurement of process variables, measurement additions via WirelessHART technology, valve performance improvements to handle the various olefin plant load conditions, loop dynamic analysis and tuning, and steam system management and control. The paper provides further thoughts in each of these areas.

Doug recommends developing an automation energy savings program and beginning with a full assessment of current operating conditions. This not only helps with the justification, but also provides the benchmark to compare improvements against to provide return on investment. He counsels that a part of this assessment is to identify the control and advanced control loops that have a major impact on energy usage. He has another matrix of energy loss consequences versus historical frequency for monitoring and maintenance. This analysis helps prioritize financial impact and focus the justification efforts.

Whether or not you're an Olefins producer, you'll gain some insight in how to find and plan a path to energy savings.

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Technologies continue to be introduced, which impact our lives. In the world of process automation, wireless technologies connecting instrumentation to process automation and asset management systems are impacting the way process manufacturers can operate their plants. The Emerson European Chemical industries team will be hosting a series of webinars to show ways chemical manufacturers are using these wireless technologies to improve the way they operate their plants. The first one is coming up in a few weeks on July 6th. I'll update the post with the link to the WebEx registration once it's live.

The global economic conditions have reduced consumer spending and business investment, particularly in the automotive and housing sectors. This slowdown has directly impacted chemical manufacturers' sales and in turn production. During recessionary times, the focus of plants often shifts away from growth toward improving operational efficiency.

At lower production levels, it's important to squeeze out costs to continue to remain profitable. Areas that might have opportunity for improvement include energy efficiency, maintenance savings, water usage, environmental impact reductions, and improved safety. Also, product margins can be preserved by producing differentiated products.

You may recall Peter Cox, a key member of this team from an earlier post. Through him and the team, I got my hands on early builds of information the Chemical Industry specialists will share in the webinars. They see four key areas where wireless instrumentation can help overall efficiency through: improved reliability, increased production, increased visibility to out-of-reach areas, and leaner operations.

A reliability example they cite is any process that has rotating process units, such as reactors or kilns. Wired approaches are tricky and typically have high mechanical failure rates. For one chemical manufacturer, their rotating reactor had to be shut down 2-3 times per week to repair the instruments and/or associated wiring, which no longer was communicating with a PLC. They mounted two wireless pressure/temperature transmitters, one on each end, which communicated with a Wireless Gateway connected via MODBUS to the PLC. This approach ended the measurement reliability problems and improved the efficiency and quality of the product produced in the reactor.

One other example I'll share is in increasing visibility. A chemical manufacturer needed a way to keep up-to-date inventory on storage tanks to support their product sales. Because of the remote location of these tanks from the production plant area, wired measurement was prohibitively expensive. Using wireless differential pressure transmitters, they could send accurate tank level measurements to the inventory management system and allow operators to spot problems with the tank more quickly. It also reduced the need to send the operators into this hazardous area to perform manual tank level readings.

Peter shared with me that the webinars would get increasingly specific and more technical on the applications that chemical manufacturers are solving with wireless plant and field network technologies.

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Update and Bump: The Chemical webinar page with registration is now open.

I heard a few weeks back that Emerson's Dr. Doug White, was going to be honored by the American Institute of Chemical Engineers (AIChE). I was sworn to secrecy, which is not an easy thing for someone with an itchy finger on the "publish" button. Since the press release is now out, it's safe to talk about Doug.

He is a Principal Consultant for the Process Systems and Solutions business and has held positions such as Vice President APC Services for Emerson, President of MDC Technology, President of Profitpoint Solutions, Senior Vice President for Automation Technology for Aspen Technology, and President and Chairman of Setpoint; all leading companies in the development of modern process plant advanced automation applications.

At this week's 2009 AIChE Spring National Meeting, Doug receives the:

AIChE Fuels and Petrochemicals Division (FPD) award, one of two FPD annual awards, for his outstanding technological contributions to the advancement of these industries.

The Fuels and Petrochemicals Division describes this award:

Recognizes individuals who have made substantial technological contributions to the advancement of the fuels and petrochemicals industries. Selection criteria includes: 1. Long and recognized record in the nominee's areas of achievement. 2. A chemical engineer and preferably an AIChE member. 3. Awardees are selected based on a combination of technical achievement, management skills, business acumen, academic leadership and general service to the profession. 4. Selection shall be balanced between the fuels and petrochemicals industries.

We have featured Doug several times on this blog, including stories of saving energy with advanced automation, justifying capital projects, and assessing energy reduction opportunities. The common thread is that Doug helps quantify the solution with the business objective. He helps engineers speak the language of finance to get the capital or expense budget required to do the project and quantify the results.

I thought in addition to Doug's wisdom shared over the years that I'd give you a little of his background. He has a BSChE from the University of Florida, an MSChE from California Institute of Technology, and an MA and PhD in ChE from Princeton. He's been a member of AIChE for more than forty years.

Doug has applied the fruits of this education and work in the field of process manufacturing and has developed special expertise in the field of advanced manufacturing automation. He has more than thirty years experience designing, developing, managing and implementing advanced automation and optimization systems in oil refineries and chemical plants around the world. He has authored or co-authored more than fifty technical papers on these subjects, many documenting first-of-a-kind system installations.

At this week's AIChE conference Doug will present, The Digital Plant: Progress and Promise. Doug discusses the current state-of-the-art in process plant sensors, automation, and information technologies and offers some projections on future developments. He shares the areas of plant operation that have seen the largest effects to date and the areas in which he expects to see the greatest impact in the future. I guess there's no time to rest on one's laurels when there is wisdom to share.

Congratulations on this well-deserved award, Doug!

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I received an email from the Center for Operator Performance (COP) about a newly completed study, Color Usage in Graphic Displays for Process Control. Emerson is one of the founding members along with members from process manufacturing, academia, EPCs, and automation suppliers. Emerson's Mark Nixon, who leads the research efforts for the DeltaV system, is also the chairman for these research efforts at the COP.

The center oversees research to meet the needs of the members and is responsible for contracting universities and human factors companies to conduct the research. The center also serves as a repository for human factors data in process control and training in human factors as requested by the members. Research interests include the following:

Expertise - With attrition of operators, much expertise is walking out the door of process plants. What makes an expert operator? What skills does an expert possess that a novice does not? How can novices become experts faster?

Simulator Effectiveness - While simulators in general are a wonderful tool for enhancing operator performance, their application in process control has historically yielded mixed results. What are the key attributes of a successful simulator training program? How important is simulator fidelity in the success of training?

Graphics & Data Presentation - Process operators deal with thousands of process variables that ultimately become the basis for a single decision. How can graphics better support this effort? What impact does background color have? Does the use of one color for more than one meaning impact performance?

Alarm Actuation Rate - What is the upper limit for alarm processing? How long can this limit be sustained without impacting performance?

The Operator Display and Color Usage study is the first of a multi-part study investigating the overall topic of display design. In this study, the researchers reviewed the current literature, surveyed operators, and visited a number of operating sites. A key component of this project was to bring the researchers up-to-speed with what the state-of-the-art is in the petrochemical industry.

As part of their learning, the researchers were looking for evidence on whether or not best practices related to color and visualizations are being followed. The 99-page color usage study is available for members of COP and was prepared by Dr. Jennie Gallimore and Jennifer Shinkle, with Wright State University. With Emerson as a member, I was able to get my hands on a copy and here are a few things I gleaned. If you're interested in the full research, here's the COP contact page.

One conclusion that the researchers came back with was that although there is considerable research on the use of color and other visualization techniques for display design, guidelines specific to the petrochemical industry are scarce. Color as well as other guidelines such as position, form, and animation could potentially help display designers to improve their overall display implementations.

The researchers also made another observation; color is probably not the most pressing problem, a bigger factor is the overwhelming number of displays and the design and presentation of the information on these displays. For example, although mimic displays such as P&ID's are simple enough to create, they are not necessarily the best way to present information to operators. Further studies are required to look into better ways to organize and present information on displays.

The research was performed working with U.S. refining and petrochemical manufacturers and their operations staff. The mean age of study participants was 46 with an average of 16 years experience. The report notes that more than half of the research participants have some form of corrected vision. As someone in this age demographic and needing those "cheater glasses" myself for dimly lit rooms, I can appreciate this growing trend.

The research also looked at lighting conditions in the operator rooms, environmental conditions (temperature, humidity, noise, and vibration), total colors used in operator displays, alarm-related colors used, and different aspects of display element effectiveness. It looked at many other things too, including display technology, considerations in vision and color perception, and ways color is used in visual displays. From the responses, the study points to opportunities for improvement to better define color usage and visualization guidelines.

I asked Mark his key take away from the research. Mark notes that although there is considerable research behind visual encoding techniques, that research has not made its way into our industry. A key challenge that people responsible for configuring displays face are that there are few guidelines describing best practices and for the best practices that do exist, there is very limited research proving that the techniques actually work in our industry. The center's goal is to provide that research. A well-designed operator interface will improve overall plant operations and environmental, health and safety conditions. The members of the COP share these objectives and are jointly funding this research.

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As reported by the Automation Gear blog, a big breakthrough has come to Micro Motion Coriolis flow meters. They can now be powered with two wires. These same wires carry the process variable and digitally communicate other process variables back to the process automation system via HART.

I did some reading and learned that that ultra-low power technology in the transmitter coupled with an optimized Coriolis sensor design made it possible to power these flow and density meters on a 4-20mA HART signal. Process manufacturers should continue use the 4-wire design for the real demanding applications like fiscal metering and custody transfer, meter verification and ones with entrained air.

Outside of these demanding applications, many mass flow, volume flow, density and temperature applications are well suited for the 2-wire Coriolis meter.

I caught up with Tom O'Banion, who leads the chemical industry efforts in Emerson's Micro Motion division. He noted that Coriolis technology has increasingly been used to measure liquids and gases because of its accuracy and reliability compared with other flow measurement technologies.

With units typically spread over great distances, installation costs have been one limiting factor in the use of Coriolis technology. Tom noted one refiner's estimate of $15 per foot plus labor for the cost of pulling the additional power wires needed for the 4-wire transmitter. This can add up quickly in tank farm or hydrogen metering applications that are typically long distances from the rack room.

Many natural gas metering stations on individual units were installed when natural gas was inexpensive--$1/Mscf. With prices now closer to $8/Mscf, chemical manufacturers and refiners want to track natural gas usage much more closely to optimize their operating costs. A typical small ethylene cracker may consume $200-$300 million in natural gas per year. Instead of differential pressure across orifice plates or turbine meters, a two-wire Coriolis meter can more accurately measure natural gas consumption and provide the flow, density and temperature measurements via HART back to the automation system for tighter control.

Another application Tom mentioned is hydrogen metering. It is usually located along the perimeter of the refinery. It's very expensive and quite difficult to measure with conventional technologies. Using the existing wiring, the 2-wire Coriolis meter provides more accuracy and less maintenance.

Tom also noted that installation costs with the additional wires sometimes prevented the use of Coriolis technology in applications for which it was better suited--especially if the analysis had been based on installed costs rather than lifecycle costs (which favors Coriolis technology with no moving parts.) The two-wire version shrinks the installed cost difference.

It's great that technology continues to advance to create more opportunities to optimize and save energy. I'll continue to pass along applications as I come across them.

I've written about terminal and offsites operations a few times in the past. I had a chance to catch a presentation given by Emerson's Shoyeb Hasanali, who leads the terminal management solutions team.

Shoyeb began by giving us a good grounding on terminal operations. These facilities provide receiving, shipping and storage facilities for liquid or gaseous products processed by or produced in a refinery or petrochemical complex. These sites typically include tank farms, blenders and loading and unloading facilities. The loading and unloading facilities may handle truck, rail, marine or pipeline transport of these liquid and gaseous products.

Some of the issues terminal operators currently face is a lack of spare capacity to handle additional bulk products, increasing safety, environmental and regulatory compliance requirements, and an increasing number of product variations.

The rapid price increase in refined products has caused a shift in the movement patterns and logistics in the transportation of these products. The automation and information systems within existing terminals were not designed for the current economic climate and rapid changes in spot prices. Terminal operators often have disparate automation systems for custody transfer, loading/unloading, blending, vapor recovery and other units.

Shoyeb and his team of terminal management solution consultants work with terminal operators to provide front end engineering design (FEED) to identify the opportunities to improve the flow of accurate and timely information required in rapidly-changing price world.

The FEED study is typically followed by functional designs, functional requirements and factory acceptance testing for the hardware and software used in the solution. Much of the technologies for these solutions come from various businesses within Emerson Process Management. These include Saab Rosemount tank gauging, Daniel custody transfer, metering skids, loading rack presets, Micro Motion flow and density measurement, METCO metering services and DeltaV blend control.

The team has delivered projects all over the world on products including gasoline, diesel, jet fuel, asphalt, fuel oil, lube oils, chemicals, fertilizers, liquefied petroleum gas, liquefied natural gas and specialty chemical products.

I've highlighted the topic of plant turnarounds (planned downtime for maintenance) a few times in the past. Back from the Emerson Exchange, here's my take on the Smart Turnaround workshop. For continuous processes that run for years, this turnaround provides opportunity to update, fix, repair, and replace a host of plant assets including instruments, valves, electrical distribution equipment, connectors and cabling, and the overall performance of the process.

The Emerson presenters looked at the advanced planning that can be done from these various perspectives. From these diverse areas of expertise, diagnostic testing helps develop a turnaround plan that prioritizes critical asset work, defines the scope of work, develops the schedule for the work, and identifies the parts and people required to best get this difficult work done.

Chris Forland an operations consultant whose work I've highlighted in earlier posts kicked off the session discussing some of the challenges of the turnaround process. A big one is finding problems you didn't expect while in the turnaround. These unexpected problems cause extra charges and delays. Chris discussed ways that Emerson turnaround specialists can help with the detailed planning to make sure the work is efficiently performed during the turnaround. He noted that less time to plan mean less flexibility as the turnaround date approaches. Other challenges included maintaining compliance with safety and regulatory compliance, working with budget constraints, reducing process variability, losing experienced personnel due to infrequency of turnarounds, and pressuring of short turnarounds due to sold out condition of produced product.

Scott Grunwald, a turnaround business manager in the Instrument & Valve Services business, recommended that with the valves and instruments, you start by building the plan based on the benefits to be achieved the roles of all participants in the maintenance activities, and the prioritized list of activities and anticipated timelines. The process starts with a walk down of the facility. Next, FlowScanner is used to measure internal valve conditions to identify problems to address during the turnaround. When it's time for executing the turnaround, only valves needing significant work are removed. Other valves are repaired in place.

The team often brings an on-sight mobile trailer that is a self-contained workshop to rework the instrument and valves right on-site. This helps to expedite the repair process.

Looking at turnarounds from an electrical reliability perspective, Steve Metzger described the goal--to prioritize and focus the resources by pre-diagnosing troubleshooting, followed by the planning of the repair services and parts required to get the lead times properly. The key is to do as much pre-work as possible, fix what's possible, and remove it from the scope of the turnaround to lessen the pile of work to be done.

On-line partial discharge testing before the turnaround detects cables with degrading insulation that could cause short circuits and unexpected downtime. This testing helps determine which cables are OK and which need to be replaced during the turnaround.

James Beall, also highlighted in earlier posts, summed up the goal of a Smart Turnaround--to identify the items you can fix in advance, and prioritize what can't be in the turnaround plan. James and the variability management consultants look at the control performance and opportunities to reduce process variability through better tuning. James gave an example of a mixing temperature control loop where the deadtime was nine minutes between a change in setpoint and response the temperature was changing. The problem was not in the loop tuning but rather in the lag caused by the temperature transmitter being located 250 feet from where it should have been. Finding this early in the process allowed this installation mistake to be scheduled and fixed during the turnaround.

Chris closed this presentation with how you can look at the return on investment to help justify the experts required to make the planning and execution of the turnaround a success. It's a bit of a chicken and egg scenario since you don't know what type of ROI this turnaround planning can create without having the experts come in to begin the process of identifying improvement opportunities.

Chris has developed a model based on turnaround experience with typical costs from each of the aspects of turnaround planning and typical costs for the maintenance activities. This model is in an excel spreadsheets so that the assumptions can be easily changed to fit the unique aspects of each process manufacturer. Both cost avoidance and increased revenue from improved plant performance is calculated, each based on the size of the process and amount of equipment considered.

By taking a comprehensive planning approach, and getting an early start, turnarounds do not have to cause quite the number of gray hairs that they have traditionally been known to cause.

Update: Mitzi Amon, director of marketing for Emerson Electrical Reliability Services team adds that the prioritization is accomplished by performing online diagnostic testing prior to the turnaround to determine what electrical equipment needs to be serviced during the turnaround. This helps clearly define maintenance work scope during the turnaround and what can be done prior to the the turnaround.

A leading research organization, the Aberdeen Group, says it well when they say:

In asset intensive industries, such as automotive, metals, mining, oil and gas, process manufacturing, utilities, and the public sector, the reliability and productivity of capital assets is essential to an organization's financial success. Maintenance of these assets can dramatically impact the overall performance and useful life of an asset.

Petrochemical manufacturers definitely consider themselves in this "asset intensive" group. As such, solid maintenance programs are essential. And it is especially critical to plan the times when they are shut down for maintenance. Known in industry parlance as a turnaround, these may happen only every 4-6 years. This means they frequently involve new personnel as people move on to new roles.

A Houston, Texas-based petrochemical manufacturer saw an Emerson Exchange presentation given by Emerson's Instrument & Valve Services (IVS) consultant Wade Enns. He described a Northern Alberta Oil Sands production project with 120,000 I/O to commission. A key to the success of this project was the use of the Smart Start project services methodology. It helped bring a well thought out plan and order to this huge commissioning task.

This methodology and associated software provides embedded check sheets and commissioning procedures for 196 specific equipment types, customized check sheets for planning and checking off tasks during the turnaround as they are completed. The process also helps prioritize the maintenance activities and documents them to provide an audit trail, should the refiner need to refer back to the maintenance activities performance.

The petrochemical manufacturer shared how they had real problems with their last turnaround with scheduling and quality of the work performed. Obviously, any delays impacting the start-up schedule mean lost revenue.

The IVS team worked with the manufacturer to plan the maintenance turnaround on the process with 600 loops and 1800 devices. The process began by building a Smart Start Project Tool database to capture the entire scope of the instruments and valves which were in use. The team took advantage of the plants installed AMS Device Manager. Next, to fully understand and document how everything was installed, they performed "loop walk-downs". This helped put together the plan for the priority and order of the maintenance to be performed.

Working collaboratively, the maintenance and IVS team fully documented and received signoff on the plan in time for the turnaround. With milestones in place, the team could catch deviations from the plan early so that additional resources could help in these areas.

The results were what this manufacturer wanted--a smooth turnaround executed in the allotted time. Given the pressures on everyone to get the maintenance work done in the allotted schedule, having this well thought out and documented plan definitely helped reduce the stress along the way.

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.

A continuing theme to several of these blog posts is how process manufacturers are looking for ways to improve energy efficiency in these times of high energy costs. One way to do this is to optimize the steam required for a distillation process.

I caught up with Pete Sharpe whom you may recall from an earlier post on reducing costs of APC projects using pre-engineered applications. Pete has recently completed some work for a specialty chemical manufacturer that wanted to improve the performance of the distillation columns by decreasing the steam required and decreasing the reflux flows to the columns.

Pete worked with the process engineers to apply model predictive control (MPC) technology found in the SmartProcess Distillation Optimizer. This application is one of the pre-engineered SmartProcess applications Pete described in the earlier post.

The distillation process is a classic multivariable problem with control variables, manipulated variables and constraint variables.

Using model predictive control, the column can be controlled and operated as a unit instead of a collection of loops.

In addition to reduced operator load, the process engineer identified 400 lb/hour savings in steam on one of the columns and close to 900 lb/hr on the first column where the Distillation Optimizer application was implemented. With a cost for 135 psi steam of $5 per klb, this translates into energy savings of more than $50,000 USD for these particular columns. This savings adds up as all of the distillation columns on site are converted over from multi-loop control to MPC-based control. Steam reductions are a result of lower reflux flows that have been reduced by about 20%. While this change increases the average overhead impurities as is expected, it is well within specifications.

Now that the Distillation Optimizer has demonstrated stable results on two of the columns, Pete is working with the process engineers to implement it on the remaining columns over time. Beyond better performance and increased efficiency, the best measure of the success to date has been operators leaving the MPC control on more than 90% of the time. This is one of the true tests according to Pete and the Advanced Automation Services team.

Congratulations to Praxair's Geismer, Louisiana methane reforming production facility for winning Chemical Processing magazine's Plant Innovation Award.

Praxair's innovations were the result of their objectives to reduce energy (natural gas) usage while meeting the production demands for CO, H2 and steam much of which is exported to customers' neighboring plants. The Geismar facility is comprised of four steam reformer plants of different age. The key challenge was to allocate load based on current plant performance and product slate.

I spoke with Chris Hawkins, a Senior Consultant and Technology Manager in Emerson's Asset Optimization organization. The AO team worked with Praxair to design advanced site optimization using the AMS Optimizer to calculate values for key process variables in real-time to increase the energy efficiency and consistency of each of the individual units. This work was combined with some model predictive control strategies implemented by the Praxair project team.

Working with the Praxair team, AO team members developed detailed models in the AMS Optimizer for each of the operational components of the site. The models compare the current plant operation and customer demands to determine the most economic set of production setpoints across the multiple units. These setpoints are automatically sent to the lower level control systems to keep the process running at optimal efficiency.

Chemical Process magazine reported the following results from the project:

Individually, the MPC systems increased in the carbon monoxide recovery on the cold boxes an average of 5-8% across multiple units, and much more consistently running of the units during production changes and load disturbances. Full implementation of this approach cut energy usage by over 1.0% for the facility. While that may not seem like a large percentage, for a site of this size, such a reduction equates to several hundreds of thousands of dollars a year in savings and provided a project pay back on the order of 2 years.

I recently heard a presentation from one of our Chemical industry experts, Peter Cox, an Operations Consultant based in our Emerson Belgium office. Peter spent 14 years with BASF in various engineering and management positions before joining Emerson.

One of the key issues European Union chemical manufacturers are facing is that they ensure compliance with the SEVESO II Directive released in 2005 (COMAH in the United Kingdom.)

The guidelines were named after an industrial accident which occurred in Seveso, Italy in 1976.

The directive states the requirement for a mandatory review to prove compliance with the safety regulations at least every five years for every plant in the European Union and U.K which falls under these directives.

In an earlier post I discussed how Emerson safety experts are helping process manufacturers use the IEC 61511 performance-base safety standards to address these safety regulations.

Peter believes that Chemical manufacturers must take a holistic look at the safety lifecycle from risk identification, to the classification of these risks, to the design of the safety function, through the ongoing maintenance and testing of these safety functions.

Emerson is helping Chemical manufacturers in this area with safety expertise and smart safety instrumented system technologies.