Effect of the Water Condensation Rate with the Presence of Gas Condensate in the Wet Gas Pipeline

Abstract

Pipelines are a common medium to transfer hydrocarbons, but their integrity is compromised by corrosion issues specifically in top of line corrosion (TLC) due to several influence factors such as water condensation. Water condensation occurs due to a significant variance in temperature outside the pipeline and inside the pipeline as water condenses in the inner pipeline. Hence, this paper aims to study the water condensation rate (WCR) behaviour in the presence of gas condensate in wet gas pipelines. The objectives of the research are to determine the components of the gas condensate by characterizing the gas condensate using Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier-Transform Infrared Spectroscopy (FTIR) equipment and later to determine the effect of gas condensate on water condensation rate by conducting 2 different experiments. The condition of TLC was imitated by using a customized TLC testing unit, whereby 2 sets of API 5L X65 carbon steel coupons were used. Meanwhile, the delta temperature of the gas and steel obtained by regulating the temperature setting of the chiller and hot plate respectively enabled the water condensation process to be simulated. Throughout the 7-days of experiments, the gas and steel temperature were daily monitored and the water that only condensed on the surface of the coupons was collected and measured. Subsequently, the WCR was determined. The first objective was achieved as the result from GC-MS showed that there were 67 compounds in the condensate, and 5 functional groups were detected using FTIR, which confirmed that the gas condensate used in this experiment was similar to the gas condensate obtained from the pipelines. The second objective proved that condensate affected the water condensation rate, in which the WCR was reduced by about 73% with the presence of condensate. This WCR reduction is postulated because of the two different liquids (water and hydrocarbon) competing for the same surface area (top metal coupon) to condense.