New insights into the evaluation of kinetic hydrate inhibitors and energy consumption in rocking and stirred cells

Foroutan, Shima; Mohsenzade, Hanie; Dashti, Ali; Roosta, Hadi

doi:10.1016/j.energy.2020.119507

Cited by 19 publications

(14 citation statements)

References 82 publications

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“…Afterwards, the cells were charged with the CO 2 at a given pressure as required for the experiment. The detailed description of the rocking cell apparatus can be found elsewhere [ 45 , 56 , 70 ]. Different methods were used to study the phase behavior, induction time and formation and dissociation kinetics of hydrates in Milli-Q water and in aqueous solutions of ionic liquids as described below.…”

Section: Methodsmentioning

confidence: 99%

“…In the present work, we have performed extensive thermodynamic and kinetic testing of the two ILs at different concentrations for CO 2 and THF hydrate formation and growth using a rocking cell apparatus. It has been reported that this apparatus consumes less energy compared to stirred cell apparatuses while screening the performance of newly developed low-dosage hydrate additives [ 45 ]. The reason to choose CO 2 was because CH 4 and CO 2 both form sI type hydrates and CO 2 poses a relatively low greenhouse effect.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Thiouronium-Based Ionic Liquids on the Formation and Growth of CO2 (sI) and THF (sII) Hydrates

Soromenho¹,

Keba²,

Esperança³

et al. 2022

IJMS

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In this manuscript, two thiouronium-based ionic liquids (ILs), namely 2-ethylthiouronium bromide [C2th][Br] and 2-(hydroxyethyl)thiouronium bromide [C2OHth][Br], were tested at different concentrations (1 and 10 wt%) for their ability to affect CO2 (sI) and tetrahydrofuran (THF) (sII) hydrate formation and growth. Two different methods were selected to perform a thermodynamic and kinetic screening of the CO2 hydrates using a rocking cell apparatus: (i) an isochoric pressure search method to map the hydrate phase behavior and (ii) a constant ramping method to obtain the hydrate formation and dissociation onset temperatures. A THF hydrate crystal growth method was also used to determine the effectiveness of the ILs in altering the growth of type sII hydrates at atmospheric pressure. Hydrate–liquid–vapor equilibrium measurements revealed that both ILs act as thermodynamic inhibitors at 10 wt% and suppress the CO2 hydrate equilibria ~1.2 °C. The constant ramping methodology provides interesting results and reveals that [C2OHth][Br] suppresses the nucleation onset temperature and delays the decomposition onset temperatures of CO2 hydrates at 1 wt%, whereas suppression by [C2th][Br] was not statistically significant. Normalized pressure plots indicate that the presence of the ILs slowed down the growth as well as the decomposition rates of CO2 hydrates due to the lower quantity of hydrate formed in the presence of 1 wt% ILs. The ILs were also found to be effective in inhibiting the growth of type sII THF hydrates without affecting their morphology. Therefore, the studied thiouronium ILs can be used as potential dual-function hydrate inhibitors. This work also emphasizes the importance of the methods and conditions used to screen an additive for altering hydrate formation and growth.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Thiouronium-Based Ionic Liquids on the Formation and Growth of CO2 (sI) and THF (sII) Hydrates

Soromenho¹,

Keba²,

Esperança³

et al. 2022

IJMS

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“…Stirring promotes the mixing of incompatible gas and liquid, and it rapidly renews the reaction interface, thereby enhancing the transfer of heat and mass. Continuous stirring simultaneously increases material diffusion, accelerates material dissolution in the liquid phase, shortens the induction period, and increases the rate of hydrate formation [41,42]. Golombok et al [43] suggested that hydrate formation is limited by insufficient gas-liquid mixing.…”

Section: Characteristics Of Hydrate Formationmentioning

confidence: 99%

Hydrates for Cold Storage: Formation Characteristics, Stability, and Promoters

Chen¹,

Han

Chen

et al. 2021

Applied Sciences

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The potential of hydrates formed from R141b (CH3CCl2F), trimethylolethane (TME), and tetra-n-butylammonium bromide/tetra-n-butylammonium chloride (TBAB/TBAC) to be used as working substances for cold storage was investigated to provide a solution for unbalanced energy grids. In this study, the characteristics of hydrate formation, crystal morphology of hydrates, and the stability of hydrate in cyclic formation under 0.1 MPa and at 5 °C were carried out. It found that the ice had a positive effect on the hydrate formation under same conditions. Upon the addition of the ice cube, the induction time of R141b, TME, and TBAB/TBAC hydrates decreased markedly, and significantly high formation rates were obtained. Under magnetic stirring, the rate at which TBAB/TBAC formed hydrates was significantly lower than that when ice was used. In microscopic experiments, it was observed that the TBAB/TBAC mixture formed hydrates with more nucleation sites and compact structures, which may increase the hydrate formation rate. In the multiple cycle formation of TBAB/TBAC hydrates, the induction time gradually decreased with the increasing number of formation cycles and finally stabilized, which indicated the potential of the TBAB/TBAC hydrates for application in cold storage owing to their good durability and short process time for heat absorption and release.

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“…Most KHIs, on the contrary, minimize health, safety, and environmental (HSE) risks . KHIs are often added with synergists that improve their performance, which can include alcohols, glycols, ethers, ionic liquids, salts, or any other polymeric/nonpolymeric chemicals. , …”

Section: Introductionmentioning

confidence: 99%

“…47 KHIs are often added with synergists that improve their performance, which can include alcohols, glycols, ethers, ionic liquids, salts, or any other polymeric/nonpolymeric chemicals. 48,49 Polymers based on cyclic amides (lactams) and acrylamide were the first commercially available and used KHIs. 13,21,50−56 Numerous homo/co/terpolymers of cyclic amides (lactams) and acrylamide have been synthesized and tested for hydrate inhibition over the past two decades by several researchers.…”

Section: Introductionmentioning

confidence: 99%

Review of Kinetic Hydrate Inhibitors Based on Cyclic Amides and Effect of Various Synergists

Singh

Suri

2021

Energy Fuels

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This Review presents a comprehensive literature review of an important class of kinetic hydrate inhibitors (KHIs) that is based on cyclic amides (lactams). The major aspects of the KHIs, such as their synthesis, inhibition mechanism, toxicity, biodegradability, performance, and cloud point, are thoroughly discussed. Data for 70 KHIs made of homo/co/terpolymers from 330 experiments are collected and evaluated for performance. The effects of the inhibitor concentration, molecular weight, monomer ratio of the co/terpolymers, and 35 different synergist chemicals on various KHIs are also studied. In conclusion, the top 10 KHIs with the highest performances that had a cloud point above 70 °C are presented. The copolymer (1:1) N-vinylpyrrolidone/N-vinyl-caprolactam (VP/VCap) is found to have the highest induction time (IT) of 13 to 14 h at 0.25 wt % and at a cooling rate of 1 °C/h. Some KHIs like Inhibex BIO-800 and poly(N-vinyl azacyclooctanone) (PVACO) also have a very high ITs (17 and 13.5 h, respectively) at 0.25 wt % and at a cooling rate of 1 °C/h, but they have low cloud points (<25 °C). Guanidinium salts (n-Bu6GuanCl/n-Bu6GuanBr) and a phosphonium salt, (n-Pe)4PBr, are found to be the best synergists for the cyclic-amide-based KHIs. When used at 0.15 to 0.30 wt % along with the KHIs, they further increase the IT by 3–5 h.

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New insights into the evaluation of kinetic hydrate inhibitors and energy consumption in rocking and stirred cells

Cited by 19 publications

References 82 publications

Effect of Thiouronium-Based Ionic Liquids on the Formation and Growth of CO2 (sI) and THF (sII) Hydrates

Effect of Thiouronium-Based Ionic Liquids on the Formation and Growth of CO2 (sI) and THF (sII) Hydrates

Hydrates for Cold Storage: Formation Characteristics, Stability, and Promoters

Review of Kinetic Hydrate Inhibitors Based on Cyclic Amides and Effect of Various Synergists

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