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  • Proper Employment of Guided Wave Radar in Steam Loops

    This paper will address the application of Guided Wave Radar (GWR), also known as Time Domain Reflectometry (TDR), in your steam loop. Included will be discussions of how this technology functions and differs from more traditional forms of level indication.

    The heart and soul of any boiler based power generation system is the steam loop or circuit. Without the proper availability of water in this system, efficiency suffers. In more extreme circumstances damage to other components from either too much water (carryover) or too little water (low water condition) will occur and shorten a boiler's lifespan. In the most extreme situation a dry fire accident could occur resulting in severe damage and personal injury.

    Level indication in the steam loop is critical, yet the methods employed to measure it have been slow to evolve or change. Some of that has been due to code requirements (PG-60 of the ASME Boiler and Pressure Vessel Code) or a simple lack of confidence in "new" technology. It has only been in the past 15 to 20 years (recent in terms of boiler/steam loop history) that technologies such as magnetic level gages or differential pressure devices have been used in place of direct reading glass gauges on applications such as feedwater tanks, high pressure preheaters or hotwells. These same devices are now utilized for drum level indication as well. The most recent addition to the technology basket for steam loop applications has been Guided Wave Radar. Used in conjunction with other technologies it is seen as a reliable cost effective choice for redundant level measurement in all steam loop applications, including drum level.

  • Proper Media Compatibility, Sensing Topology and Grounding Ensure Long-term, Trouble-free Pressure Measurements in Wet and Noisy Electrical Environments

    Water is a key element to life. It plays an important role in the world economy, as it functions as a solvent for a variety of chemical substances. 71% of the Earth's surface is covered with water and 97% of that water is in oceans and saline. Only 3% of the earths water is fresh and can be found in the polar caps, glaciers, ground aquifers, lakes, swamps and rivers. In parts of the world where there is limited or no access to fresh water, desalination is being used to convert saline water to drinking water. To manage resources and the flow of water, modern electrical pumps and control systems are employed. Water chemical compatibility and electrical interference are two major challenges for the control systems. Let's ook at two major sources of fresh water and the issues that can limit the performance of the control system.

    American Sensor Technologies
  • Radioactive Isotopes in Process Measurement

    An Objective Look at the Roles of Cesium-137 and Cobalt-60 in Nuclear Measurement Systems for Industrial Processes

    Level and density measurements in process control are performed by a number of technologies. When the process temperature, pressure, or chemistry is an issue, then nuclear measurement systems have the advantage. These are non-invasive to the vessel and unaffected by the process pressures and chemistries.

    Overall, a nuclear measurement system used for process control consists of a gamma energy emitter and detector. An emitter is placed on one side of a vessel to broadcast a beam of energy to the opposite side of the vessel. The detector is placed in the beam on the opposite side of the vessel. The detector will scintillate in the presence of gamma energy and register counts proportional to the field strength. When the process value (level or specific gravity) is low, the detector will register a high number of counts since less gamma energy is blocked by the process material. When the process value is high, more of the gamma energy is blocked which leads to fewer counts.

    The two most common gamma emitters used for level and density process measurements are isotopes of cobalt and cesium. The goal of this article is an objective comparison of the roles of cesium-137 and cobalt-60 in process measurement. This will be accomplished by reviewing the properties of the two materials and then comparing the use of the materials in process measurement.

    Vega Americas Inc.
  • Reduce Energy Costs and Enhance Emissions Monitoring Systems

    The thermal mass flow meter's ability to deliver a direct reading of mass flow rates of air, natural gas and other fuel gases provides a simple, reliable, and costeffective method for tracking and reporting fuel consumption.

    Accurate, repeatable measurement of air and gas, at low and varying flow rates, is also a critical variable in combustion control. Conventional flow meters require pressure and temperature transmitters to compensate for density changes. The thermal mass flow meter, however, measures gas mass flow directly, with no need for additional hardware. The thermal meter also provides better rangeability and a lower pressure drop than orifices, venturis, or turbine meters.

    Energy prices are subject to frequent and abrupt changes and fluctuations. When energy prices are high, daily accounting of natural gas usage should be made a priority for large industrial facilities with multiple processes and/or buildings. Fuel gas flow meters are used to analyze demand, improve operating efficiency, reduce waste and adjust for peak usage. Thermal mass flow meters are frequently used for these energy-accounting applications. In addition, thermal flow meters can help plant managers provide accurate usage reports for environmental compliance, as well as compare measured usage to billing reports from gas providers.

    Rich Cada, Fox Thermal Instruments, Inc.
  • Remote Emergency Shutdown Device Improves Safety and Performance at Oil Production Platform

    Updated government regulations created a need for a major international oil and gas company to install a direct, real-time communications link at a platform located off the coast of Louisiana in the Gulf of Mexico.

    ENI Petroleum is an Italian multinational oil and gas company with around 78,400 employees at sites in 77 countries. ENI operates in the oil and gas, electricity generation and sales, petrochemicals, oil field services construction and engineering industries. It has oil and natural gas production of almost two million barrels per day, with exploration and production efforts at sites throughout North American, Africa and Asia.

    One of these production locations is an oil well platform called the "Devil's Tower" that is located just off the coast of Louisiana in the Mississippi Canyon region of the Gulf of Mexico. The platform rises 5,610 ft. above the sea bed. Until 2010, it was the deepest production truss spar in the world. Drill ships perform periodic operations within close proximity to subsea pipelines that transport oil and gas to and from the production platform.

    In this white paper, you will learn how a new data concentrator system allowed the control room and drill ships to communicate at a distance of more than 100 km, providing security in case of an incident while avoiding costly shutdowns.

    Jim McConahay, P.E., senior field applications engineer, Moore Industries and Richard Conway, facility engineer, ENI Petroleum
  • SCADA Systems - Looking Ahead

    This white paper provides insight into the evolution of the modern SCADA system and looks to the very near future by discussing such timely topics as:

    • Improving system efficiency and security
    • Managing field data and
    • Open standards

    Schneider Electric - Control MicroSystems
  • Signal Conditioning and PC-Based Data Acquisition Handbook

    The third edition of this handbook has been totally revised to include new chapters on Electrical Measurements, Vibration and Sound, Displacement and Position Sensing, and Transducer Electronic Data Sheets (TEDS). It also includes several new subjects and expands on selected items including Fundamental Signal Conditioning.

    All chapters have been enhanced to address more practical applications than theoretical measurement issues. They cover a major topic with sufficient detail to help readers understand the basic principles of sensor operation and the need for careful system interconnections. The handbook also discusses key issues concerning the data acquisition system's multiplexing and signal conditioning circuits, and analog-to-digital converters. These three functions establish the overall accuracy, resolution, speed, and sensitivity of data acquisition systems and determine how well the systems perform.

    Data acquisition systems measure, store, display, and analyze information collected from a variety of devices. Most measurements require a transducer or a sensor, a device that converts a measurable physical quantity into an electrical signal. Examples include temperature, strain, acceleration, pressure, vibration, and sound. Yet others are humidity, flow, level, velocity, charge, pH, and chemical composition.

    Measurement Computing
  • Special Report from Automation Fair 2012 - Smart. Safe. Sustainable.

    The editors of Control and Control Design compiled this special report from the 21st annual Automation Fair event, hosted by Rockwell Automation, in Philadelphia, November 5-8. This interactive PDF includes more than 20 articles documenting highlights ranging from executive keynotes and new product announcements to vertical industry forums and Rockwell Automation Process Solutions User Group and Safety Automation Forum meetings.

    Control/Rockwell Automation
  • The 10 Commandments of Wireless Communications

    In this white paper, Mike Fahrion discusses 10 basic rules that will help you ensure success in the design and implementation of your wireless network.

    B&B Electronics, Mike Fahrion
  • Top Five Missed Opportunities with HMI Alarms and Events

    With any new tech device, whether a cell phone or plant-floor controller, there is inevitably a helpful feature or two you overlooked while reading the manual or taking the introductory tutorial. Although these technological devices still perform their desired, basic functions - discovering an underutilized feature makes you wonder how you ever operated the device without it.

    Interacting with alarms is one of the basic functions your operators expect from their human-machine interface (HMI) software. However, if you're only using the standard alarming functions, you may be missing out on lesser-known features that could help you save time, ease troubleshooting and reduce headaches. The five FactoryTalk Alarms and Events functions listed below are often overlooked and underutilized. See where they fit and if you can find some hidden tools in your plant-floor applications.

    Tony Carrara, Rockwell Automation
  • Unlocking Automation Systems for Higher Business Responsiveness

    Every manufacturing industry is experiencing an increasing speed of business in several areas including changing schedules, customer needs, costs of materials, business models, and technologies. At the same time, many manufacturing sites - particularly in the discrete industries - have growing complexity in their operations which makes it more difficult to adapt. There are more SKUs and data to keep track of due to product proliferation, smaller lot sizes and compliance to government regulations.

    The demands for improved speed and agility conflict with the plants' ability to respond. Visibility into current operations, including the control system, is the primary reason manufacturers buy Manufacturing Execution Systems (MES). This visibility provides the information necessary for informed decision making in real-time by all levels of personnel - plant floor to the executives.

    MES applications contain the critical business processes for executing a production schedule. These systems perform the production-centric functions of planning, controlling, operating and informing. Control systems execute these functions to produce the goods needed to fulfill customer orders. By integrating MES with control systems, manufacturing becomes more agile for responding to change in this increasingly dynamic business environment. Integrating the control system with the MES allows for more effective and broader set of production management functions to improve operational performance.

    To improve their response to operational issues, managers look to technology for connecting plant floor and business systems for automated business processes. Some manufacturers have implemented point solutions on a case-by-case basis. Because of the higher development costs and support issues, this approach is not acceptable. An integration platform is needed.

    ARC Advisory Group
  • When and How to Inspect, Clean and Calibrate pH Sensors

    This paper will address
    - Knowing when to do a pH sensor calibration versus a calibration check
    - How to properly clean a pH sensor
    - How to perform a pH sensor calibration
    - A decision tree for step by step guidance

    The phrase in the above title is actually incorrect in its sequence of wording. All pH readings are supposed to be taken and accepted only when the pH sensor is clean. After all, a contaminated pH sensor may yield an incorrect reading. So one must make sure the sensor is clean before doing a calibration. Once a pH sensor is installed in the process and operating, how do you determine when it is time to take the sensor out of the process and do a cleaning, or a calibration? Does one perform both a cleaning and a calibration or just a cleaning, or just a calibration, or does one just perform a calibration check in buffers or...?

    This is something that can be quite confusing, especially when the operational practices and procedures documented by your company's Quality Control or Environmental Practices department may not be specific enough when they describe the procedure or the timing on when to conduct the pH calibration and maintenance. Inversely, the procedures may be too specific, detailing many more procedures and operations than are actually required.

    In practical terms, users must develop their own maintenance and calibration schedule. This schedule is accomplished by taking the pH sensor out of the process after a set amount of time, perhaps after a day or two to perform a visual inspection of the sensor. If after inspection you find no debris or fouling on the electrode and reference surfaces with the naked eye, rinse the sensor off in distilled water and perform a buffer check.

    Fred Kohlmann, Endress+Hauser
  • Yokogawa User Group: Integrated Solutions for a Sustainable Future

    Halloween in New Orleans this year saw more than the usual array of costumed revelers on Bourbon Street. Indeed, hundreds of process automation professionals descended on the Crescent City to exchange ideas and best practices at Yokogawa's 2012 User Group Conference and Exhibition. The Control editorial team was on hand and developed this exclusive report of presentation highlights--on topics ranging from safety system risk management to the latest in data acquisition technology.

    Control Global Staff
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