Products tagged with 'desorption'

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51318-10805-Understanding Film Persistency using Adsorption and Desorption Studies

Product Number: 51318-10805-SG

Author: Sunder Ramachandran / Zhengwei Liu / Carlos Menendez

Publication Date: 2018

$20.00

This paper describes corrosion inhibitor tests that were carried out at different temperatures and interpreted using Langmuir adsorption and desorption.

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Surfactant Corrosion Inhibitor Adsorption and Desorption Kinetics in Aqueous CO2-Containing Environments

Product Number: 51324-20915-SG

Author: Ryan Abou-Shakra; Joshua Owen; Richard C. Woollam; Richard Barker; William H. Durnie

Publication Date: 2024

$40.00

Corrosion inhibitors are commonly employed to internally protect carbon steel pipelines in aqueous carbon dioxide (CO2)-saturated environments, such as those encountered in oil and gas production and geothermal operation. However, unexpected events can occur that lead to periods where corrosion inhibitor addition ceases completely, or the quantity of inhibitor added falls short of the typical concentration required for the desired level of corrosion mitigation. In these instances of interruption, there is a limited understanding of the inhibitor surface residence time, or ‘persistency’, and the associated effects on the corrosion rate of carbon steel. This study examines the influence of the substrate surface condition and inhibitor concentration on the persistency of benzyldimethyltetradecylammonium chloride (BAC-C14) corrosion inhibitor in a CO2-saturated 1 wt.% NaCl brine at 30°C. An electrochemical rotating cylinder electrode (operating at 1000 rpm) coupled with a dilution process was used to simulate persistency. Experimental results using carbon steel at 0.75x and 1x of the surfactant critical micelle concentration (CMC) showed that inhibitor efficiency and persistency improved markedly at the higher concentration. Supplementary experiments using pure iron illustrated an even stronger interaction between inhibitor and substrate, resulting in BAC-C14 failing to desorb after three days of exposure to uninhibited brine. A first-order kinetic model was assessed in its ability to predict the desorption response after dilution, based on fitting to the inhibitor adsorption response. Whilst a strong agreement was obtained between the theoretical desorption profile and experimental desorption data at 0.75xCMC on carbon steel, the model failed to predict the responses at CMC, as well as those on the pure iron substrate, necessitating consideration of other models.

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The Irony of Creating a Lining Failure in the Process of Inspection

Product Number: 51324-21128-SG

Author: Steve Liebhart

Publication Date: 2024

$40.00

Inspection and shipping schedules often require hydrocarbon storage tanks and rail cars to be removed from service and turned around quickly. This can be for lining/tank inspection or to clean and repurpose it, among other reasons. For whatever reason needed the tank is drained, and any remaining material, including all vapors, must be removed for safe entry into the tank. This process might involve forced heat and ventilation but is not often precisely controlled and even less often are details of the process documented. After cargo is evacuated from the tank the hope is to find the lining intact, and then return it to service as soon as possible. During the process of evacuating volatile material from the tank it is important to handle the lining with care and attention so not to allow the empty tank shell and lining to heat up too fast. This is a dangerous scenario for the well-being of the lining if heated too fast while it contains volatile materials absorbed in the film. When a lining saturated with volatile hydrocarbon is rapidly subjected to increased temperature an equally rapid increase in vapor pressure occurs as the material changes from liquid to gas. Damage to the lining can occur if the vapors can’t escape before generating enough pressure to form blisters and/or cracks. This paper/presentation will discuss the physical phenomenon occurring during the heating and desorption of gasoline from a lining recently removed from immersion service, and how inadvertently damaging the lining during this sensitive process can occur. The purpose of this work is to raise awareness of this phenomenon and show how the long-term performance of a lining can be dramatically impacted in a matter of minutes if not appropriately cared for. Some guidance on how to avoid this problem will also be discussed.

Products tagged with 'desorption'

51318-10805-Understanding Film Persistency using Adsorption and Desorption Studies

Surfactant Corrosion Inhibitor Adsorption and Desorption Kinetics in Aqueous CO2-Containing Environments

The Irony of Creating a Lining Failure in the Process of Inspection

Association for Materials Protection and Performance