Innovations Chances for Improving the Efficiency of Operation and Maintenance

Transcription

1 Innovations Chances for Improving the Efficiency of Operation and Maintenance New technologies facilitate damage prevention and ensure system availability thus contributing to increase the efficiency of operation and maintenances activities By Dr. Gerald Linke, E.ON Ruhrgas Gas Technology Competence Centre, GERMANY 1 Abstract In recent years, the gas industry has attracted widespread attention in discussions about how to achieve climate protection targets and reduce pollutant emissions. This has been due not only to the fact that natural gas is the most environmentally friendly fossil fuel, but first and foremost to its innovative strength in the area of gas appliance development and in renewable energy production (biomethane). The use of condensing appliances in combination with solar technology or geothermal systems, the field trials of micro-chp units developed for domestic use and the research on fuel cells span what is a very diverse range of technologies from the environmentally friendly systems already available today to next-generation appliances. In this process, the uninterrupted availability of the infrastructure needed for the transmission and distribution of natural gas is taken for granted, and the technologies themselves only play a secondary role in the public debate and even appear rather static at first glance. But the opposite is true: Research and development in the gas transmission sector have made a lasting contribution to the proper functioning of the infrastructure and its value. This article looks at innovations from three different perspectives: 1. Safety 2. Availability 3. Efficiency 2 Safety: New "excavator detection" technology now puts fast location of pipeline damage within reach Gas transmission pipelines are built and operated in accordance with the state of the art. Compliance with applicable codes and standards provides a high level of inherent safety. However, external effects, which can damage a pipeline or even cause a leak, cannot be fully excluded. So there remains the risk of damage caused by earthworks involving excavators, drilling equipment, trench cutters or other heavy machinery. Responsibility for this kind of damage lies first and foremost with the personnel or the organisation causing the damage. Yet it is particularly gas companies and network operators who have developed new means of reducing the number of incidents involving damage to pipelines and cables. They include quick and easy-to-use information systems such as 1

2 "where2dig" allowing construction companies or other organisations involved in a construction project to check whether the planned project will in any way affect a local utility or network operator. According to the experience of gas suppliers and network operators, however, construction companies occasionally fail to comply with their obligation to obtain this information or damage a line even though they are aware of its existence, or they simply fail to report damage caused to such infrastructure. Sometimes it takes years before a defect is identified as part of a routine in-line inspection or a close-interval survey to detect coating holidays. Now, though, there are new technologies designed to instantaneously record and locate any contact between construction equipment (excavators, trench cutters, drilling equipment, etc.) and a pipeline. A number of competing methods and systems are currently undergoing trials. They include optical waveguides or fibre-optic systems installed alongside pipelines, which make use of different physical phenomena including - optical interferometry i.e. interference effects of two monochromatic light signals in neighbouring fibres to detect strong vibrations or deformations caused by a change in length of the light paths in the fibres, or - optical interference produced by temperature abnormalities caused by leaking substances acoustic methods designed to analyse signals picked up by microphones (so-called hydrophones) which "eavesdrop" on the gas flow at distances of 5 to 15 km, an electric method which uses the existing measuring points of cathodic protection (CP) systems to detect a "short circuit" caused by an excavator, drilling equipment or a trench cutter etc. coming into metallic contact with the pipeline (see Fig. 1). 2

3 Fig. 1: Detection system designed to pick up unwanted contact between an excavator and the pipeline Especially the last of the above methods, the electric excavator detection method (also known as RPM exploration detection 1 ) promises a range of benefits: Compared with fibre-optic and acoustic systems, the likelihood of false alarms due to the measurement principle is very low. Compared with acoustic monitoring systems, even slight scratches or minor knocks with a comparatively low impact energy (as in the case of drilling) is safely detected. Installation costs are far lower because the system dovetails with CP and remote potential monitoring systems already in place. Field tests planned for the coming months will show how far the innovative idea now turned into a prototype is still away from market maturity. 1 RPM is an abbreviation meaning remote potential monitoring. The RPM excavator detection system has been developed by E.ON Ruhrgas AG. 3

4 3 System availability: Innovative tools such as PIMS 2 facilitate the introduction of condition-based maintenance and provide an optimised reinvestment strategy Over the last few years, a range of methods and tools designed to improve system availability were developed to market maturity. With these methods and tools, high system availability is achieved through a process encompassing a series of steps: 1. Determination of the system condition 2. Assessment (which may include an actual-vs.-target-condition comparison) 3. Decision on corrective action to be taken 4. Monitoring of corrective action and return to process step 1 Methods capable of assessing the system condition include, for example: CHARM, the helicopter-borne laser-based methane detection system developed by E.ON Ruhrgas. It provides an "integral" assessment of a high-pressure pipeline network because it scans the whole pipeline corridor over a width of up to 20 metres and is capable of detecting even the smallest traces of methane (gas leaks). Operated at an average travel speed of about 40 km/h, the system thus lends itself to checking and assessing large pipeline networks "online" (i.e. during the flight). However, CHARM is a reactive system because it cannot be used to assess the condition of the pipeline system before a leak occurs. This requires much more data and information. PIMS (see Fig. 2), a complex IT system which uses steps 1 to 4 above: - Step 1: Obtain data from intelligent pig inspections, close interval surveys, excavations, etc. to determine the condition of the pipeline system. - Step 2: Assess condition using generally accepted methods (including codes and standards such as DIN EN 1954 as well as the ASME and DNV codes). E.ON Ruhrgas has condensed the condition assessment rules of these codes into an internal standard and has defined additional criteria including limit values for maximum corrosion rates and wall thickness abnormalities (E.ON Ruhrgas standard entitled "Rules for demonstrating the technical integrity of pipelines"). - Step 3: Perform the necessary corrective action (excavation, repair of small corrosion defects by grinding, removal of components, etc.) within the specified times. - Step 4: Monitor all work. Monitoring is essentially ensured by a workflow tool used as part of step 3 for scheduling all corrective measures. This tool is then also used for monitoring the work. IMMeR. This acronym stands for integrity management of metering and regulating stations. As with PIMS, the system analyses a range of data allowing the operator to decide whether to change inspection intervals (reduce maintenance cycles) or reinvest in a system. The data used include master data such as the type and age of the system as well as operating data and unusual occurrences observed during repair and maintenance work. The SAP-based system provides an honest and 2 PIMS is an acronym for pipeline integrity management system. E.ON Ruhrgas operates its own development which is based on international standards (cf. CEN/TS 15173, etc.). 4

5 transparent picture of the M&R stations' overall condition. It is an excellent tool for optimising reinvestment plans and thus helps to ensure the safety and availability of all technical assets. Fig. 2: Pipeline integrity systems are used to demonstrate that assets such as pipelines are capable of fulfilling their intended purpose safely and reliably even after years of operation. 4 Efficiency: Optimising operational processes Network services can play a major role in improving efficiency in the transportation sector e.g. by providing the right IT for standard activities. Geographic information systems help to quickly and reliably find the location where work needs to be performed (repairs or isolation of a pipeline section, etc.) and keep all relevant drawings and diagrams electronically available. Mobile workplaces allow field staff to reduce travelling times by starting from home. Fleet management systems help to reduce response times and find the right technician closest to the place of work. Case-based applications provide details of switching operations to be performed when a pipeline needs to be isolated to minimise the effect on customers and 5

6 shippers. The system also contains information on supply alternatives, which may include rerouting supplies to entire service areas. This list of many small improvements and interesting innovations in operational processes is almost endless. Yet there is one innovation which stands out as it improves the safety and availability of gas installations at the same time. This innovation is the "Gas Cam" (Fig. 3) developed by E.ON Ruhrgas. Fig. 3: The methane detection camera known as "Gas Cam" shows even the smallest gas leaks. This easy-to-operate gas camera has revolutionised gas leak detection at sites by making natural gas visible though what appears at first glance to be a very simple method for the user but is in fact a very sophisticated process based on infrared spectroscopy. The system allows small traces of methane at process plants to be detected quickly and reliably. So a quick pan shot of the area replaces gas detection involving direct sensors, which requires much more time and effort. 5 Summary The innovations described here in the areas of plant safety, availability and operation efficiency illustrate the gas industry s extensive innovation activities in the transportation sector. These innovations guarantee the full availability of all functions and help to preserve the value of the infrastructure that is a prerequisite for the security of energy supply. 6