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![Fig. 3 e Chemical structure of sodium alginate, adapted from Rehm [17].](profile/Jose-De-Castro/publication/350433940/figure/fig3/AS:1015024185253892@1619012032281/e-Chemical-structure-of-sodium-alginate-adapted-from-Rehm-17_Q320.jpg)
Gas hydrates are ice-like compounds that can affect the flow assurance in oil and gas pipelines due to their structural characteristics. Alginate is a polysaccharide naturally derived from the brown seaweed Phaeophyceae and is produced as an extracellular material by bacteria, such as Pseudomonas and Azotobacter. The novelty of using alginate as a...
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... to retain water and its biocompatibility, gelling, viscosifying, and stabilizing properties allow its wide use in the industry [12]. Alginate is a polysaccharide naturally derived from the brown seaweed Phaeophyceae and is composed of randomly 1e4 linked b-D-mannuronic acid and a-L-guluronic acid, M blocks and G blocks, respectively [13,14] (Fig. 3). Alginate can also be produced as an extracellular material by bacteria such as Pseudomonas and Azotobacter, which are abundant in vegetatively growing cells [15]. Furthermore, the alginates produce by these bacteria do not o u r n a l o f m a t e r i a l s r e s e a r c h a n d t e c h n o l o g y 2 0 2 1 ; 1 2 : 1 9 9 9 e2 0 1 0 have ...
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... The research on the inhibition effects of natural green products, e.g. starch [20][21][22], protein [23][24][25], cellulose [26,27], and polysaccharide [28][29][30], have gained in popularity gradually in recent years. These natural polymer products have the characteristics of environmental friendliness and show great potential in the field of methane hydrate inhibition. ...
Methane hydrate blockage has been a major problem to be solved urgently in the industry of petroleum and natural gas. In this work, seven chitosan derivatives with various hydrophilic/hydrophobic properties were synthesized based on the biodegradable chitosan/carboxymethyl chitosan to study the relationship between the chitosan derivatives’ molecular structures and their hydrate inhibition performance. Our experimental results indicated that the inhibitory effects of chitosan derivatives on methane hydrates were significantly better than that of carboxymethyl chitosan derivatives with similar physicochemical properties or the same functional groups at the same concentration. Moreover, the length and properties of the branched chain of the chitosan derivatives played a vital role in hydrate inhibition, and the long branched chains with hydrophobic functional groups was propitious to enhance the hydrate inhibitory performance of additives. By introducing gas-induced agitation, which created a channel for methane gas to enter the aqueous solution, the hydrate inhibition mechanism of chitosan derivatives was further revealed. The experimental phenomena indicated that the chitosan derivatives with superior hydrate inhibition effects enhanced the interfacial resistance of gas molecules migrating to the liquid phase, thus significantly reducing the gas dissolution velocities and prolonging the induction time of hydrate formation. This study verified the vital role of chitosan derivatives in inhibiting crystallized methane hydrate and provided inspiration for the further research and development of efficient and environmentally friendly kinetic inhibitors.
This study introduces solid-state tuning of a mesostructured cellular foam (MCF) to enhance hydrogen (H2) storage in clathrate hydrates Grafting of promoter-like molecules (e.g., Tetrahydrofuran), at the internal surface of the MCF resulted in a substantial improvement in the kinetics of formation of binary H2-THF clathrate hydrate. Identification of the confined hydrate as sII clathrate hydrate and enclathration of H2 in its small pores was performed using XRD and high-pressure 1H NMR spectroscopy respectively. Experimental findings show modified MCF materials to exhibit a ⁓ 1.3 times higher H2 storage capacity as compared to non-modified MCF under the same conditions (7 MPa, 265 K, 100% pore volume saturation with a 5.56 mol% THF solution). The enhancement in H2 storage is attributed to the hydrophobicity originating from grafting organic molecules onto pristine MCF, thereby influencing water interactions, and fostering an environment conducive to H2 enclathration. Gas uptake curves indicate an optimal tuning point for higher H2 storage, favoring a lower density of carbons/nm2. Furthermore, a direct correlation emerges between higher driving forces and increased H2 storage capacity, culminating at 0.52 wt.% (46.77 mmoles H2/moles H2O and 39.78% water-to-hydrate conversions) at 262 K for the modified MCF material with fewer carbons/nm2. Notably, the substantial H2 storage capacity achieved without energy-intensive processes underscores solid-state tuning's potential for H2 storage in the synthesized hydrates. This study evaluated two distinct kinetic models to describe hydrate growth in MCF. The multistage kinetic model showed better predictive capabilities for experimental data and maintained a low average absolute deviation. This research provides valuable insights into augmenting H2 storage capabilities and holding promising implications for future advancements.
