Sodium Alkyl Ether Sulfonates (SAES): Dual Anionic‐Nonionic Behavior in Synthetic Brine Having High Salinity and Hardness

In enhanced oil recovery, not only the low‐tension performance, but also the robustness at optimum formulation is an important issue. The fourth part of our review series is dedicated to robustness, defined as the width of the zone exhibiting three‐phase behavior around the optimum formulation, whatever the scanned variable. It is first corroborated from a screening of the available data in the literature that the tension minimum is inversely proportional to the square of the three‐phase range in the HLD scale. However, since there is still an inaccuracy of about a factor 10 in the tension minimum, some significant improvement can be attained in some cases by increasing the three‐phase behavior width in two ways. The first approach consists of finding systems that are insensitive to some formulation variable such as temperature, surfactant mixture composition or concentration, and water‐to‐oil ratio. The second way is to produce an artifact through which the optimum formulation is produced twice in a scan. If the distance between the two events in the scan is reduced down to be zero, their corresponding three‐phase behavior zones merge and result in a wider WIII region with a low tension. Several cases of such events are reported: alkaline scans, anionic‐nonionic and anionic‐cationic mixture changes, linear change in composition in three‐surfactant mixture, partial precipitation from a surfactant mixture in a salinity scan, and excessive partitioning of polyethoxylated nonionics. More complex transitions with three effects in a single scan or three concomitantly scanned variables show even more possibilities in practice.

Section: Insensitivity To a Formulation Variable Change Reduced Sensimentioning

confidence: 99%

How to Attain Ultralow Interfacial Tension and Three‐Phase Behavior with Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 4: Robustness of the Optimum Formulation Zone Through the Insensibility to Some Variables and the Occurrence of Complex Artifacts

Salager

Antón

Arandia

et al. 2017

“…For aqueous surfactant solution, the surface tension increased with the increase in density of –CH 2 group (Al‐Faraji et al, 2015; Ju et al, 2017). It is well known that surfactants with shorter carbon chains and longer EO chains are more hydrophilic, resulting in a higher cmc value (Binana‐Limbelé et al, 1988).…”

Section: Resultsmentioning

confidence: 99%

Nonylcyclohexanol ethoxylates, a green alternative of nonylphenol ethoxylate, on the interfacial physiochemical properties aspects

Ren

Xia

et al. 2021

Nonylphenol ethoxylates (NPEOn), typically NPEO10, are the second popular nonionic surfactants that have been banned or restricted from use and production by Europe since 1990 due to their poor degradability and high genetic toxicity. The hypothesis of this work is that the nonylcyclohexanol ethoxylates (NCEOn) may possess similar interfacial properties but lower biotoxicity and better biodegradability compared with NPEOn according to their structures. To verify this and to find the optimal alternative of NPEO10, the interfacial properties of NCEOn were compared with the typical commercial ethoxylates nonionic surfactants, such as nonylphenol ethoxylated‐10 (NPEO10), alcohol ethoxylated‐9 (AEO9), secondary alcohol ethoxylated‐9 (SAE9), and isomeric alcohol ethoxylated‐9 (TO9). It is the NCEO7 that shows excellent emulsifying ability similar to that of NPEO10. NCEO11 performed stronger detergency than other assayed commercial nonionic surfactants. Additionally, NCEOn possessed lower biological toxicity to aquatic organisms. Hence, NCEOn could be considered as a green substitute for NPEOn in the assayed application fields.

Effect of Sodium Carbonate on the Cloud Point in Alkyl Ether/Brine Systems: Apparent Relation with Dynamic Interfacial Tension Minimum

Hadji

Aoudia

Al-Rubkhi

et al. 2016

The effect of Na2CO3 on the cloud point in Na2CO3/surfactant/brine was investigated using two series of nonionic surfactants, C13EOx and C17EOx. The cloud point, Tcp, was found to decrease linearly with increasing Na2CO3 concentration. This was attributed to Na+ and particularly to CO32−salting‐out effect. The slope a = dTcp/d[Na2CO3] became more and more negative as the degree of ethoxylation is increased, suggesting that the higher the number of ethylene oxide (EO) groups the stronger is the cloud point depression for a given increment in Na+and CO32−ions in solution. This was also illustrated by the linear variation of ΔTcp = Tcp,0 − Tcp,[Na2CO3] with the surfactant degree of ethoxylation.