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Last updateMon, 27 Aug 2018 3am

Case Study: Ultrasonic gas leak detection (UGLD)

Case Study by Honeywell: Ultrasonic gas leak detection (UGLD) is capable of offering an  enhanced mechanism for detecting pressurised gas leaks in applications where more traditional technologies fail to perform effectively due to high natural ventilation rates or excessive vibration. Detection methods such as point and open path IR absorption, catalytic beads and EC cells are dependent on large localised gas clouds forming in order to detect a gas leak. Such gas clouds form well in enclosed areas however, in exposed or elevated areas subject to strong winds leaking gas dilutes quickly with the leak potentially going undetected for long periods of time.

Ultrasonic noise can be generated in a number of ways that may lead to inappropriate positioning or alarm condition such as; mechanical noise, process generated ultrasound, electrical equipment. The main reason for undertaking a survey is to measure the ultrasound in the operational plant, quite simply because we cannot hear what the detector hears. Where new build installations are considering the use of UGLD’s, assumptions of background sound levels are made based on a wealth of experience from live plant studies.

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C2+ Measurement Solutions for Turbine Control Using an Advanced Flameproof Process Gas Analyzer

To optimize plant performance and prevent expensive turbine damage, rapid control is critical for industrial power markets covering multiple energy sources. Maintaining turbine efficiency is an even higher priority today because of lower emission requirements and varying fuel sources due to the increase in unconventional natural gas sources, such as shale. Plant gas sources are primarily composed of methane, but typically there are extensive variations in higher hydrocarbons (C2+) as well. In fact, in some cases, over 18 percent variation has been recorded with fluctuations from 10 percent to 16 percent within one minute. Turbines have to be more flexible and need to present the above criteria over a wide range of loads because gas turbine power plants are often used only for peak loads.

Application:

Methane and higher hydrocarbons like ethane and propane behave differently during combustion. The variability of fuel sources can sometimes pose challenges for control and optimization, especially for combined cycle turbines with lower emissions. While a gas chromatograph can provide all the required measurements, the speed of response it provides is sometimes not sufficient for effective control.

The solution can often be a process gas analyzer (PGA) with a specific configuration of optical benches and filters that provide continuous measurement and the rapid response that’s required. In addition, an approximate calorific value (BTU) can be provided as long as the higher hydrocarbons are low in content. If this is not the case, the BTU value will be underestimated but never overestimated. Such values cannot be used for custody transfer but they may be adequate to prevent turbine damage and optimize performance. If the operator knows the variation of C2+ in the fuel sources, then that will substantially minimize the error.

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Rotork Schischek boosts biogas production at Munich waste water plant

Rotork Schischek ExMax explosionproof actuators have been selected to assist the production of biogas for district heating systems in the German city of Munich.  Biogas is produced during the effluent treatment process at the city’s largest waste water plant Klaerwerk Gut Grosslappen, situated close to the world famous Munich Allianz Arena, home to Bayern Munich football club.

The ExMax actuators have been installed in the digester and fermentation tanks, where all electrical equipment must be approved for use in hazardous areas. Built inside four large towers, the fermentation tanks mix the waste at a defined temperature to produce the biogas. For optimum performance the inner tank temperature must be maintained at 38ºC. Six ExMax actuators are installed in an area known as the lamp at the top of each tower for the operation of air dampers to balance the inside temperature with fluctuating ambient temperatures on the outside.

Factors favouring the Rotork Schischek products for this application include their compact size, ease of installation, standardised connections and Zone 1 hazardous area explosionproof certification. In addition Rotork Schischek has developed established relationships with the damper OEM, local engineering companies and the end user.

All Rotork Schischek products are manufactured with colour coding to indicate at a glance the appropriate hazardous or non-hazardous area of application. Yellow denotes hazardous Zones 1, 2, 21 and 22, red denotes hazardous Zones 2 and 22 and green denotes non-hazardous areas only

White Paper by Sierra: Sub-Metering of Natural Gas

Unlike oil, natural gas exists in abundance in the United States. Of the natural gas consumed in the United States in 2011, 95% was produced domestically. The U.S. Energy Information Administration projects U.S. natural gas production to increase from 23.0 trillion cubic feet in 2011 to 33.1 trillion cubic feet in 2040, a 44% increase. Almost all of this increase in domestic natural gas production is due to projected growth in shale gas production, which will grow from 7.8 trillion cubic feet in 2011 to 16.7 trillion cubic feet in 2040. This natural gas boon highlights the importance for utility companies to provide homes, businesses, and mid-to-large size facilities with accurate natural gas billing. Traditionally, utility companies have used diaphragm meters to measure natural gas usage, which is then charged to customers on their monthly energy bill. Although diaphragm meters are a trusted billing mechanism by utility companies, they may not provide customers with the most accurate natural gas bill. Diaphragm meters have limitations in natural gas measurement. If the diaphragm meter does not accurately measure the natural gas, this can result in utility companies overcharging customers.

To avoid this problem, many mid-to-large-size facilities use flow meters to sub-meter their natural gas usage to validate the diaphragm meters’ readings and more efficiently allocate energy.

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Rotork valve actuation selected for Australia’s giant clean LNG projects

Case Study: The three projects – Queensland Curtis LNG, Santos GLNG and Australia Pacific LNG - are developing coal seam gas in Queensland’s Surat and Bowen Basins. Hundreds of kilometres of pipelines will link the natural gas production wells on the Queensland mainland with a world-class LNG production plant under construction on Curtis Island, which will initially produce more than twenty seven million tonnes of LNG for export each year. These coal seam gas projects are centred on a clean and efficient energy source with half the carbon dioxide emissions of coal.

For the upstream mainland wellheads, HART-enabled Rotork CVA modulating electric actuators have been ordered for process valve control at an eventual total of 2000 widely distributed sites. In addition to the natural gas, CVA actuators will also control the flow on the extraction process for coal seam water. This resource will be treated for use by agricultural and industrial customers as well as supplementing domestic water supplies.

CVA actuators deliver continuous, repeatable modulating control with a programmable fail to position option. Resolution, repeatability and hysteresis performance is quoted at less than 0.1% of full scale, offering suitability for the most demanding control valve applications. Among other advantages, innovative CVA electric actuation removes the expense of installing and maintaining instrument air supplies at these remote sites, where the pressure of the gas itself is too low to provide a viable source for actuator operation. CVAs are also preferred because electric actuation eliminates the release of any environmentally harmful gas into the atmosphere during valve operations.

Nearly 1000 Rotork Skilmatic SI and EH range electro-hydraulic actuators have been ordered for control valves, shutdown valves, wellhead skids and metering skids. These self-contained actuators combine the simplicity and convenience of electrical operation with the modulating precision of hydraulic actuation and the reliability of mechanical failsafe motion. Designed to SIL3 standards for use in safety critical applications, Skilmatic actuators are also programmable for partial stroke testing, enabling valves to be tested without interrupting routine processes.

The orders for Rotork electric actuators are completed with IQ actuators for various isolating valve automation duties. All the Rotork electric actuator ranges feature advanced and user-friendly non-intrusive programming and commissioning technologies, combined with integral data logging, diagnostics and asset management capabilities.

The balance of Rotork orders on this giant project involves fluid power actuators for the pipeline and the LNG plants on Curtis Island. The majority of these are CP and GP range pneumatic actuators operating butterfly valves on LNG production lines. The actuators are customised with control packages to meet specific operating duties, including SIL2 and SIL3 applications.