Abstract

Glycols are widely used prevent the hydrate formation in sub sea pipelines and in gas plants to control dew point. Operating experiences of diethylene glycol (DEG) and monoethylene glycol (MEG) for preventing hydrate in gas pipelines and dew point control have been performed to evaluate the unexpected operational problems in gas processing system. Field test and laboratory experiments were carried out to investigate the type of glycol the fluid solidification condition formonoethylene glycolanddiethyllene glycolin the presence of hydrocarbons and salts. Results led us to make modification in the gas plant and choose the right type of glycol with optimum dose to simplify operation and save costs in gas processing in Egypt. This paper cover all aspects of the process from type of glycolto nozzle placement and locations to low temperature separators to enhance the performance and quality control of gas processing. This study will address the operational issues with practical solutions are presented. These deal with glycol contaminated by a high salt content from completion fluids and hydrate formation in offshore gas lines, design modification to process equipment and changing from DEG to MEG for sales gas specification. This paper also addressee the proper glycol type to fit with gas composition, proper glycol injection rates, nozzle sizing, placement and location according actual field data not textbook data that is central in the designed recommended process parameters.

Introduction

Gas plant is a hydrocarbon dew point control plant, Joule Thomson process, JT, which processes gas from an offshore platform in the Nile delta area of the Mediterranean sea. The nominal plant inlet design capacity is 350 mmscfd, achieved via two parallel JT processing trains of 165 mmscfd capacity each. The plant was constructed in 1999–2000. The raw gas from offshore wells are conditioned at the gas plant to produce gas with sales quality specification. The gas hydrocarbon and water dew points are controlled by means of low temperature condensation. Diethylene glycol80% is injected into the gas at various points, to hydrate formation in offshore and onshore in low temperature parts of the process.

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