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Automation Technologies 4/2015

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Automation Technologies 4/2015

CONTROL AND DRIVE

CONTROL AND DRIVE TECHNOLOGY Safe automation between Myanmar and China AUTOMATION TECHNOLOGIES 4/2015

CONTROL AND DRIVE TECHNOLOGY next page A 2,500 km gas pipeline from Myanmar to China, requires smooth failure-free operation. To make sure that the gas pumped from Myanmar reaches China’s energy hungry industry, safely and consistently, a largely automated operation and monitoring system with safe process controls and functional safety in accordance to SIL 3 is being employed. This automation system PSS 4000 from Pilz follows the mechatronic approach and is characterised by the consistent distribution of control functions to the periphery. For the control function, therefore, it is irrelevant where the respective program section is processed. But that’s not all: PSS 4000 performs automation and safety-related tasks simultaneously, in the one system. The gas pipeline extends from the west coast of Myanmar, formerly Burma, to Kunming in Yunnan province and is intended to cover part of China‘s huge energy requirement and make the country less dependent on sea transportation. The pipeline is a joint venture between the stateowned China National Petroleum and Myanmar Oil & Gas Enterprise. The ambitious project was launched in 2009; the gas pipeline has been operating since July 2013. Around 30 billion cubic metres of gas now flows annually from west to east; a crude oil pipeline planned simultaneously is under construction. Reliable and safe operation over 2,500 km 14 compressor and transmission stations along the length of the pipeline are responsible for a smooth, failure-free operation when transferring the gas. The automated processes are linked to defined safety levels, which are intended to keep the hazard risks for man, the environment and damage to the pipeline as low and improbable as possible. In order to transport the gas reliably and safely over long distance, a certain pressure and the corresponding optimum temperature must be maintained. If the pressure falls the temperature will drop. Due to the specific properties of the gas, this increases the risk of ice formation – with the subsequent negative impact on gas flow and the pipeline. Beijing based Guo Peng Technical Co.Ltd, as part of the consortium of project partners it was responsible for preventing ice formation and maintaining a continuous gas flow, using an electrically heated system. Multiple sensors monitor the temperature and the flow rate along the entire length of the pipeline system: if values of these parameters fall below a defined minimum value, the heating system starts up. Similarly, a defined maximum value ensures that the heat supply is switched off again appropriately. According to the requirements of the pipeline operator, this safeguard procedure runs automatically with absolute reliability. But what type of safety device is suitable for monitoring the execution of the switching signals reliably? If temperature and gas flow values were to exceed or drop below defined values without being detected, in an extreme case this could cause an explosion with harmful effects for man and the environment, as well as long-term loss of the gas supply. Consequential costs would quickly run into millions. Zhu Yi Ming is the engineer at Guo Peng Technical Co. who is responsible for the development and reliable operation of the heating system; he recalls one of his early stays in Germany: “I was struck by what at the time was an outstanding safety solution on a large hydraulic press; it was a Pilz solution”. So he contacted Pilz‘s subsidiary in Beijing. As a gas pipeline is essentially nothing other than a complex AUTOMATION TECHNOLOGIES 4/2015

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