Flow-Assurance Methods Enabled by Medium-Voltage Heating Technology

Abstract

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 26389, “Flow-Assurance and Hydrate-Prevention Methods Enabled by Medium-Voltage Electric Heating Technology,” by C. Molnar and M. Riley, Chromalox, prepared for the 2016 Offshore Technology Conference Asia, Kuala Lumpur, 22–25 March. The paper has not been peer reviewed. Copyright 2016 Offshore Technology Conference. Reproduced by permission. Medium-voltage electric heating systems offer reduced installation cost and increasing efficiency for multi-megawatt oil and gas heating applications compared with low-voltage systems. For offshore applications, the systems offer the added benefit of both space and weight reductions. The technology is based on the same principles as low-voltage electrical-resistance heating that has been used in industry for the past century, but reapplied for medium-voltage use. Introduction Most industries use low-voltage systems, typically less than 1,000 V, for electric heating applications. These were practical for most applications through the 20th century. Now, however, many applications in heavy industries such as oil and gas, petrochemical, and chemical demand much higher power output. These applications require multi-megawatt electric heating systems. At low voltages, such requirements lead to challenges with power distribution, process design, and costs. A viable solution involves leveraging medium-voltage power. A safe and reliable technical design for metal-sheathed electric heating and power controls exists for heating systems operating at medium voltages. These medium-voltage electric heating systems allow the oil and gas industry to capture all the advantages of electric process heat while minimizing the disadvantages of low-voltage, high-amperage designs. Description and Application of Equipment and Processes A medium-voltage electric heating element is capable of very large power output that can operate on voltages up to 7,200 V. Modified dielectric material formulations are capable of ultrahigh insulation resistance and enable the element to reach values in excess of 25,000 V during safety testing. These two properties deliver the performance and reliability necessary for industrial applications, even at temperatures up to 540°C.