Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M Cairn India Limited. Skin Effect Heat Management System 3 Cairn India is building the world’s longest continuously heated and insulated pipeline (~700 km) to evacuate the crude from the Mangala field in Rajasthan. The export pipeline route from source at the Mangala Production Terminal to the Gujarat coast at Bhogat via Salaya, passes through the states of Rajasthan and Gujarat covering eight districts and more than 250 villages. In addition, there are 4 branch lines ranging in length from 2.5 km to 21 km delivering crude to customers enroute. Currently, 600 km section from Mangala to Salaya, along with four branch lines if fully operational. The necessity of evacuating the Rajasthan crude, which is waxy in nature and needs to be maintained above 65 °C to ensure its flow, resulted in customizing existing heating technology into the Skin Effect Heat Management System (SEHMS), an innovative system by far the longest of its kind in the world today. SEHMS technology has traditionally been most often applied to shorter above ground applications. There were many innovations required to apply this technology to an underground cross country pipeline system. The crude oil pipeline is insulated with 90 mm Poly Urethane Foam (PUF) to arrest the heat loss from pipeline to the surrounding soil; this is further enclosed with a 5 mm HDPE jacket for protection and to make it water SEHMS technology also known as the Skin Trace System (STS) or Skin Electric Current Tracing (SECT), are all dependent on the same principles of skin and proximity effect for operation. They are all established and proven electrical heating technologies used for long distance piping and pipelines. SEHMS generates heat on the inner surface of a carbon steel heat tube that is welded to the carrier pipe to be heat traced, which in our case is the 24” crude pipeline. An electrically insulated, high specification temperature-resistant conductor is installed inside the heat tube and connected to the tube at the circuit end. The tube and conductor are connected to an AC voltage source in a series connection. This method of heating is called skin-effect heating because the return path of the circuit current is pulled to the inner surface (approximately 1 mm) of the heat tube by both the skin effect and the proximity effect between the heat tube and the conductor. The outside surface of the heat tube is at ground potential, and completely safe, while the inner surface of the tube carries full current. The heating circuit impedance AC VOLTS (Outside Surface to Earth) AC VOLTS (Inside Surface to Earth) Heat Tube (with insulated wire inside Carrier Pipe Fluid Thermal Insulation STSTM System is mainly resistive, generating heat in the heat tube wall and, to a lesser extent, in the insulated conductor. Additional heat results from eddy currents induced in the heat tube wall by the current flow through the insulated conductor. The allowable circuit length is determined by the power output; heat tube size; conductor size; and the carrier pipe temperature. SEHMS ‘s advantage over other electrical trace heating systems is that extremely long circuit lengths are possible – typically a pipeline of up to 20 km may be heated from a single electric supply point (2 circuits of 10 km each). In ideal situations the SEHMS heating system is not required on the MangalaBhogat Pipeline as the 90 mm of PUF pipeline insulation will be good enough to keep heat losses within acceptable limits. C Tyco Thermal Controls LLC However, certain operational situations, such as low flows or a stoppage, could lead to wax formation at lower temperatures (<65 °C), and for this reason SEHMS is a critical system because without it there would be no way to re-melt the crude oil and keep the pipeline operational. The key SEHMS elements are transformers, heat tube, pull boxes, end boxes and temperature sensors. For this project, and in a first for India, an insulation plant was set up at the pipe manufacturers Mill using cutting edge spray applied insulation techniques. Fuel for the gas engines producing the power for the pipeline heating system comes from an 8 inch diameter pipelinelaid parallel to the main 24 inch Cairn India Limited Cairn India Limited Necessity, as they say, is the mother of invention, and in the case of Cairn it was the same for this innovation of technology. tight. Above ground heating stations with maximum 1 MW power generating units installed at every 20 km along the pipeline route supply power to SEHMS. In addition, 2 intermediary terminals and a total of 36 heating stations are installed along the pipeline route. S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M 2 5 STSTM System S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M 4 Termination Power Source and Temperature Monitoring RTD’s Heat Tube Tyco Thermal Controls LLC W A T E R Cairn India Limited Cairn India Limited C 6 7 S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M A view of the Mangala development pipeline showing the SEHMS and the Raageshwari Gas Pipeline crude pipeline. The primary gas source is from Cairn’s Raageshwari field in Rajasthan. Skin Effect Heat Management System was chosen as a suitable solution due to the following advantages: The details of the Power Source and Temperature Monitoring are as follows: • • • • Safe • Custom engineered • Easy to maintain • Rugged and reliable • Provides built in redundancy • Cold re-start capability • Successfully used in similar conditions • • • Mangala Development Pipeline Project is unique as it is believed to be by far the longest such continuously heated and insulated pipeline in the world. Currently, the longest pipelines using this technology are in Russia (160 km) and Indonesia (115 km). Cairn India Limited Cairn India Limited • Power requirement – 40 W / m Voltage – Approx. 4000 V No current flow on outside skin of tube System earthed & grounded with earth fault automatic trip Remote emergency shut-down capability Current flows through center conductor Current returns through inside skin of outer tube Since the start of pipeline operations in 2010, the SEHMS system has performed capably and contributed importantly to the pipeline, achieving world-class availability levels and has proven to be a robust and reliable technological solution to effectively solve flow assurance issues with waxy Mangala crude oil. This is the largest scale application of this technology. S K I N E F F E C T H E AT M A N A G E M E N T S Y S T E M CAIRN INDIA LIMITED Cairn India is one of the largest independent oil and gas exploration and production companies in India with a market capitalisation of ~US$ 10 billion and the fastest-growing energy company in the world as adjudged by the Platts 2012 and 2013 Rankings. Cairn India operates more than 25 per cent of India’s domestic crude oil production. Through its affiliates, Cairn India has been operating for more than 15 years playing an active role in developing India’s oil and gas resources. To date, Cairn India has opened 4 frontier basins with over 40 discoveries, 28 in Rajasthan alone. The Mangala field in Barmer, Rajasthan, discovered in January 2004, is the largest onshore oil discovery in India in more than two decades. Mangala, Bhagyam and Aishwariya fields – major discoveries in Rajasthan block – have gross ultimate oil recovery of over 1 billion barrels from primary, secondary and enhanced oil recovery (EOR) methods. Cairn India has a portfolio of 9 blocks - one block in Rajasthan, two on the west coast and four on the east coast of India, and one each in Sri Lanka and South Africa. Oil and gas is currently being produced from Barmer, Ravva and Cambay. Cairn India Limited. Cairn India Limited 3rd & 4th Floors, Vipul Plaza, Sun City, Sector 54, Gurgaon 122 002, India +91 124 459 3000 Follow us: Twitter - @Cairn_India LinkedIn - company/cairn-india-ltd YouTube - cairnindialtd SlideShare - cairnindia www.cairnindia.com