Efficacy of Bisulfite Ions as an Oxygen Scavenger in Monoethylene Glycol (At Least 20 wt%)/Water Mixtures

Abstract

Summary This study investigates the oxygen-scavenging behavior of bisulfite ions in monoethylene glycol (MEG)/water mixtures at concentrations commonly found in gas-transportation pipelines. Temperatures and pH values were varied. The influence of transition-metal (TM) ions to catalyze the bisulfite oxygen scavenging was studied. Experimental results indicate that MEG significantly inhibits bisulfite oxygen removal, which is hindered at low pH values and, to some extent, temperature. TMs can accelerate the oxygen-scavenging reaction in pH-unadjusted solutions, although the rate was still lower than that of the pH-adjusted solutions. The possible mechanism for such behavior and industrial implications are discussed.

Performance of erythorbic acid as an oxygen scavenger in thermally aged lean MEG

“…Likewise, the introduction of organic acids including acetic, propanoic and butanoic can occur through the condensed water phase if such acids are present within the reservoir (Latta et al, 2013;Lehmann et al, 2014). The presence of contaminants such as salts and organic acids have been found to influence the performance of certain oxygen scavengers, with sulfite-based oxygen scavengers being particularly affected by organic acids (Finkbeiner and Bush, 1968;Salasi et al, 2017). According to several studies, organic acids including acetic acid may inhibit sulfite oxygen scavenger performance through interaction with transition metals including manganese that is used to catalyze the oxygen removal reaction (Brandt and Van Eldik, 1995;Kotronarou and Sigg, 1993;Nurmi et al, 1982;Salasi et al, 2017).…”

“…The prevention of corrosion in pipelines and process equipment is an important aspect of the continued operation of MEG regeneration facilities and transportation pipelines. Various methods of corrosion mitigation for natural gas pipelines can be applied depending upon the level of formation water within the system (Halvorsen et al, 2007;Pojtanabuntoeng et al, 2017;Salasi et al, 2017). Where formation water breakthrough has not occurred, corrosion mitigation through pH stabilization is typically performed through addition of basic chemicals such as NaOH, KOH or Methyldiethanol Amine (MDEA) to promote the formation of protective iron carbonate scale (Dugstad and Seiersten, 2004;Halvorsen et al, 2007;Ivonye et al, 2015;Lehmann et al, 2014;Pojtanabuntoeng et al, 2017).…”

Performance of erythorbic acid as an oxygen scavenger in salted fresh and degraded monoethylene glycol under a magnetic memory effect

“…The oxygen scavenger at the first concentration level was injected, and the oxygen probe reading was recorded over time until it reached ˂20 ppb, indicating the end of the experiment. A minimum oxygen concentration of 20 ppb was recommended by several workers to mitigate the corrosion issues in the oil and gas industry . The experiment was then repeated using the second oxygen scavenger concentration.…”

“…The oxygen dissolved in the MEG solutions also corrodes components in different sections of the plant and transportation pipelines. Therefore, extensive studies have been devoted towards the development of strategies that substantially scavenge the oxygen content in MEG solutions . The thermal deaeration and degasification processes commonly used in the food and chemical industries consume a significant amount of energy .…”

“…Rudenko et al have reported that the thermal degradation of MEG solutions may occur in the absence of oxygen molecules, specifically above 157°C. However, other reports have emphasized that thermal degradation in the oil industry is more likely in the presence of oxygen at concentrations ≥20 ppb . Thus, to avoid thermally oxidized degradation products and corrosion further downstream during the regeneration processes, oxygen scavengers must be utilized to reduce the oxygen concentrations to ˂20 ppb.…”