Technical evaluation for the proposal of a different cricondentherm limit for the Caribbean coast within Colombian gas quality regulations

Abstract

Introduction: The cricondentherm is the highest temperature above which a liquid cannot be formed, regardless of the pressure. According to the Colombian natural gas transmission regulations, this temperature should not exceed 7.2°C. Although this restriction is currently applied over the whole country, it is possible to propose a different limit on the cricondentherm for the Colombian Caribbean coast. Methods: In this document, the current hydrocarbon dew point (HCDP) limits for gas transport pipelines in several countries worldwide are analyzed, the weather conditions on the Colombian Caribbean coast are reviewed, and a thermodynamic and hydraulic study is developed, taking into account the composition of the gas (before any treatment) from three fields on the Caribbean coast, the elevation profile of one of the gas pipelines on the Caribbean coast, and the influence of the weather conditions on the behavior of gas in the pipeline. Results: Some countries define their HCDP values depending on the region through which the gas is transported. Simulations of the chosen gas pipeline with lean gases without any treatment at the worst ambient conditions of the Colombian Caribbean coast show that there is a slight liquid condensation at 21°C, indicating a gap with the current regulations (7.2°C) in which an additional maximum cricondentherm can be proposed for the Colombian Caribbean coast. Conclusions: From this work, it is concluded that a new cricondentherm for warm climates in Colombia, within the transmission regulations, should be between 10 and 12.6°C. This proposal is based on the results obtained in simulations and the acknowledgment that some of the Colombian gas pipelines operate only in warm regions of the country.