TY - JOUR

T1 - Gas hydrate nucleation and growth in the presence of water-soluble polymer, nonionic surfactants, and their mixtures

AU - Semenov, Anton P.

AU - Mendgaziev, Rais I.

AU - Stoporev, Andrey S.

AU - Kuchierskaya, Alexandra A.

AU - Novikov, Andrei A.

AU - Vinokurov, Vladimir A.

N1 - Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/10/1

Y1 - 2020/10/1

N2 - We investigated the effect of mixtures of commercial nonionic surfactants Sintanol ALM-7 (A7), Sintanol ALM-10 (A10), Surfynol 465 (S6), Surfynol 485 (S8), and well-known kinetic hydrate inhibitor Luvicap 55W (sample P) on nucleation and growth of sII gas hydrate. The ramp method (cooling at a constant rate of 1 °C × h−1) was employed to determine hydrate onset temperature and subcooling of individual and mixed samples. The dosage of reagents varied within 0.25–1.0 mass% range. A7 and A10 were tested at concentrations of 1.6∙10−4–2.5∙10−3 mass% (about or lower than CMC) as well. All surfactants were found to be weak antinucleators of gas hydrates. The inhibition performance of the surfactants was significantly lower in comparison with Luvicap 55W. We observed that ethoxylated fatty alcohols (A7 and A10) at low concentrations demonstrated a hydrate-inhibiting action at nucleation and growth stages. The Luvicap 55W – surfactant mixtures were tested as KHIs with a total dosage of 0.5 mass%, and in the ratio of 1:1, 1:2, and 1:5. Several mixed samples (1:1 P + A10), (1:2 P + A10), (1:2 P + S6) have demonstrated the same or higher efficacy in inhibition of hydrate nucleation than pure KHI. The results obtained indicate the presence of a synergistic effect of kinetic inhibition of gas hydrate with mixtures of the polymer and ethoxylated nonionic surfactants. Among the mixtures, the best results were obtained for the sample (1:2 P + S6). Surfynol 465 is characterized by high solubility in water, low foaming (compared to other surfactants), and lower cost than vinyl lactam-based KHI. Thus, the Surfynol 465 is a promising synergist for the vinyl lactam polymeric KHI and allows reducing the dosage of the expensive polymer.

AB - We investigated the effect of mixtures of commercial nonionic surfactants Sintanol ALM-7 (A7), Sintanol ALM-10 (A10), Surfynol 465 (S6), Surfynol 485 (S8), and well-known kinetic hydrate inhibitor Luvicap 55W (sample P) on nucleation and growth of sII gas hydrate. The ramp method (cooling at a constant rate of 1 °C × h−1) was employed to determine hydrate onset temperature and subcooling of individual and mixed samples. The dosage of reagents varied within 0.25–1.0 mass% range. A7 and A10 were tested at concentrations of 1.6∙10−4–2.5∙10−3 mass% (about or lower than CMC) as well. All surfactants were found to be weak antinucleators of gas hydrates. The inhibition performance of the surfactants was significantly lower in comparison with Luvicap 55W. We observed that ethoxylated fatty alcohols (A7 and A10) at low concentrations demonstrated a hydrate-inhibiting action at nucleation and growth stages. The Luvicap 55W – surfactant mixtures were tested as KHIs with a total dosage of 0.5 mass%, and in the ratio of 1:1, 1:2, and 1:5. Several mixed samples (1:1 P + A10), (1:2 P + A10), (1:2 P + S6) have demonstrated the same or higher efficacy in inhibition of hydrate nucleation than pure KHI. The results obtained indicate the presence of a synergistic effect of kinetic inhibition of gas hydrate with mixtures of the polymer and ethoxylated nonionic surfactants. Among the mixtures, the best results were obtained for the sample (1:2 P + S6). Surfynol 465 is characterized by high solubility in water, low foaming (compared to other surfactants), and lower cost than vinyl lactam-based KHI. Thus, the Surfynol 465 is a promising synergist for the vinyl lactam polymeric KHI and allows reducing the dosage of the expensive polymer.

KW - Gas consumption

KW - Gas hydrates

KW - Hydrate nucleation and growth

KW - Kinetic hydrate inhibitor

KW - Subcooling

KW - Surfactant

KW - HIGH-PRESSURE

KW - PERFORMANCE

KW - SALTS

KW - CUTS

KW - INHIBITION

KW - AMINO-ACIDS

KW - METHANE HYDRATE

KW - EQUILIBRIUM CONDITIONS

KW - ANTI-AGGLOMERATION

UR - http://www.scopus.com/inward/record.url?scp=85088830254&partnerID=8YFLogxK

U2 - 10.1016/j.jngse.2020.103491

DO - 10.1016/j.jngse.2020.103491

M3 - Article

AN - SCOPUS:85088830254

VL - 82

JO - Journal of Natural Gas Science and Engineering

JF - Journal of Natural Gas Science and Engineering

SN - 1875-5100

M1 - 103491

ER -