19 results found
Sadeek SA, Williams DR, Campbell KLS, 2018, Using sodium thiosulphate for carbon steel corrosion protection against monoethanolamine and 2-amino-2-methyl-1-propanol, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 78, Pages: 125-134, ISSN: 1750-5836
Sadeek SA, Williams DR, Campbell KLS, 2018, Using sodium thiosulphate for carbon steel corrosion protection against monoethanolamine and methyldiethanolamine, INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 74, Pages: 206-218, ISSN: 1750-5836
Sadeek SA, Williams DR, Sedransk Campbell KL, 2017, Use of green inhibitors and pre-treated carbon steel for reduced corrosion in post-combustion capture infrastructure, EUROCORR 2017
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved. Development of strategies to implement carbon steel (CS) infrastructure in lieu of stainless steel (SS) in post-combustion CO2 capture plants will advance wide-scale deployment of this technology. Herein two proposed techniques were investigated: 1) pre-treatment of CS with 5 M methyldiethanolamine (MDEA), 2) green (i.e. low-toxicity) inhibitors: sodium thiosulphate (STS), copper carbonate (CC), and 2-mercaptobenzimidazole (MBI). Coupons (CS) were immersed for seven days in industry standard solvent 5 M monoethanolamine (MEA) to test these proposals. Pre-treated coupons demonstrated good corrosion protection with the development of a dense layer of siderite crystals, significantly reducing oxidation of the underlying Fe substrate. Copper carbonate exhibited good inhibition performance with no surface change evident after immersion. The inhibitor STS provided some corrosion protection through surface adsorption, while MBI proved least effective. The combination of a siderite layer (generated by MDEA pre-treatment) with each inhibitor was also tested. However, the integrity of the protective siderite layer was compromised in the presence of an inhibitor, ranging from nearly complete removal to some destruction.
Yu LCY, Sadeek S, Williams DR, et al., 2017, Investigating the corrosion due to high capacity and uptake promoter amine blends on carbon steel, 13th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: ELSEVIER SCIENCE BV, Pages: 1998-2008, ISSN: 1876-6102
The continued development of amine solvents for post-combustion CO2 capture is essential to the large-scale success of this technology, with particular interest in high capacity and uptake promoter blends. Some of these solutions also show reduced corrosive tendencies in the presence of carbon steel, a significantly cheaper alternative to the stainless steels generally employed. Optimization of the solution composition and reduced corrosion could yield both a decrease in capital and operating costs. Solutions (30% by weight) of monoethanolamine (MEA) or piperazine (PZ) were blended with either methyldiethanolamine (MDEA) or 2-amino-2-methyl-1-propanol (AMP). At 120 °C, Solutions containing PZ outperformed those with MEA showing the formation of good protective siderite (FeCO3) crystal layers, reducing continued oxidation of Fe from the surface and therefore corrosion.
Campbell KLS, Yu LCY, Williams DR, 2017, Using pre-treated carbon steel for post-combustion carbon capture infrastructure, 13th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: ELSEVIER SCIENCE BV, Pages: 1991-1997, ISSN: 1876-6102
The reduction of capital cost in building post-combustion CO2 capture is necessary to realize its widespread use. Cheaper steels, e.g. carbon steel, are attractive but lack the necessary corrosion resistance. To protect from corrosion, one approach is to implement a protective coating on the surface. Particularly, a coating like siderite (FeCO3) is appealing because it can be formed by amines and therefore could be regenerated. This study investigates the formation, over seven days at 40 and 80 °C, of such siderite layers formed in methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), and a K2CO3 solution. When tested against 2.5 M monoethanolamine for 28 days, the coatings formed at 80 °C in MDEA and AMP appear the most resilient. There is a substantial siderite crystal layer remaining on the surface and only minimal weight loss.
Campbell KLS, Yu LCY, Williams DR, 2017, Siderite corrosion protection for carbon steel infrastructure in post-combustion capture plants, International Journal of Greenhouse Gas Control, Vol: 58, Pages: 232-245, ISSN: 1750-5836
To mitigate CO2 release, large-scale post-combustion capture with amine solvents is essential. To achieve capital cost savings, carbon steel infrastructure can replace stainless steel if corrosion by CO2-loaded amine solvents is controlled. A coating, to protect the carbon steel, formed using an amine (or additive) is beneficial because it can be regenerated. Siderite has been shown to form a protective crystalline product layer, created when Fe oxidised at the surface reacts with carbonate ions. Tertiary or sterically-hindered CO2-loaded amine solutions can form this layer. Herein siderite was prepared on carbon steel substrates from 5 M methyldiethanolamine (MDEA), 5 M 2-amino-2-methyl-1-propanol (AMP), and 1 M K2CO3 at 40 and 80 °C. At 40 °C, K2CO3 produced the most successful protective siderite layer; by contrast, the amine solutions developed layers with interlocking crystals at 80 °C. After siderite formation, these substrates were tested in 2.5 M MEA and AEPZ, both highly corrosive but with more desirable capture kinetics. At 80 °C, substrates pre-treated with MDEA or AMP showed good resistance against the corrosive actions of MEA and AEPZ for four weeks. The siderite layer reduced Fe oxidation at the surface and ingress of solution species thereby ceasing contact and corrosion.
Yu LCY, Campbell KLS, Williams DR, 2016, Carbon steel corrosion in piperazine-promoted blends under CO2 capture conditions, International Journal of Greenhouse Gas Control, Vol: 55, Pages: 144-152, ISSN: 1750-5836
Aqueous amine promoter blends have improved CO2 absorption capacity and uptake. Tertiary (3°) and sterically-hindered (SH) amines are favoured for their molar absorption ratio, (i.e. CO2 absorption capacity). With a promoter, namely piperazine (PZ), the ordinarily slow reaction kinetics of a 3°/SH amine is accelerated. Amine blends of 30 and 50% by weight, MDEA + PZ and AMP + PZ, were tested using immersion corrosion techniques at 120 °C. In all cases, a siderite (FeCO3) product layer was formed on the surface of the carbon steel coupons. Aqueous PZ solutions produced thin layers with comparatively lower Fe ion concentrations than blended solutions. The fast CO2 capture kinetics of PZ, and therefore carbonate formation, makes the rapid reaction possible due to readily available Fe ions oxidised on the surface. The replacement of PZ content in a blend, by MDEA or AMP, resulted in slower formation of siderite and variably poorer corrosion protection. Critically, the use of AMP in the blend offers better protection against corrosion, shown by lower concentration of Fe ions in the bulk solution than parallel MDEA solutions. This can be attributed to the faster formation of carbonate species by AMP, as a SH amine, which also results in more imperfect crystals.
Yu LCY, Campbell KLS, Williams DR, 2016, Using carbon steel in the stripper and reboiler for post-Combustion CO2 capture with aqueous amine blends, International Journal of Greenhouse Gas Control, Vol: 51, Pages: 380-393, ISSN: 1750-5836
Aqueous amine solutions loaded with CO2 show a range of corrosion behaviour when in contact with carbon steels. Primary (1°) and secondary (2°) amines undergo corrosion, including the formation of iron oxide surface layers. By contrast, tertiary (3°) and sterically-hindered (SH) amines produce an excess of carbonate ions, leading to FeCO3 formation, and thereby reducing corrosion. Four amines were tested under challenging conditions (1–5 M at 120 °C) to confirm these behaviors. Due to recent interest in blended amine solvents (1° or 2° with 3° or SH) for improved reaction kinetics, CO2 absorption capacity and recoverability, four binary amine combinations (MEA + MDEA, MEA + AMP, AEPZ + MDEA, AEPZ + AMP) were tested in a range of compositions. Blends containing low concentrations of 1° or 2° amine show promise for use with carbon steel due to the formation of a siderite product layer and low corrosion levels. An increase in concentration of 1° or 2° amines, shows higher Fe ion concentrations initially as well as significant weight change to the coupon. However, the formation of more diverse product layers at longer time intervals reduces the Fe ion concentration in the bulk. Blends generally offer reduced corrosion compared to 1° or 2° amines alone, another benefit towards deployment.
Campbell KLS, Zhao Y, Hall JJ, et al., 2016, The effect of CO2-loaded amine solvents on the corrosion of a carbon steel stripper, International Journal of Greenhouse Gas Control, Vol: 47, Pages: 376-385, ISSN: 1750-5836
The corrosive behaviour of loaded amine solvents was evaluated under stripper operating conditions, for post-combustion carbon capture, to determine the feasibility of using carbon steel in plant construction. In addition to monoethanolamine, three alternative amine solvents: methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), 1-(2-aminoethyl)piperazine (AEPZ), and the common additive K2CO3 were studied when in contact with carbon steel (C1018) over a 28-day period. Corrosive behaviour was evaluated using carbon steel coupons: gravimetric method for weight change, surface imaging (SEM) and analytical techniques (EDX and XRD), and Fe ion concentration in solution (ICP–OES). The results demonstrated that MDEA and AMP as well as K2CO3 develop a significant siderite (FeCO3) layer on the carbon steel surface. The presence of this layer is attributed to the preferred reaction pathway with CO2 for tertiary and sterically hindered amines. The FeCO3 layer formed in the case of MDEA provides superior protection from continued corrosion of the carbon steel. By contrast, MEA and AEPZ show significant corrosion to the carbon steel surface. In conclusion, MDEA, AMP, and K2CO3 can preferentially produce sufficient surface FeCO3 layers to reduce corrosion levels in carbon steels for use under stripper conditions in post-combustion carbon capture plants.
Lapidot T, Sedransk Campbell KL, Heng JY, 2016, Model for interpreting surface crystallization using quartz crystal microbalance: theory and experiments, Analytical Chemistry, Vol: 88, Pages: 4886-4893, ISSN: 1086-4377
Surface crystallization of calcium sulfate was investigated using a dissipation crystal quartz microbalance (QCM-D) together with microscopy to understand the mechanical property changes occurring during the growth process. The use of optical microscopy and SEM revealed that needle-shaped crystals grow as clusters on the QCM sensor’s surface, not in uniform layers. As crystallization growth progressed, QCM-D revealed inversions between negative and positive frequency shifts. This behavior, a function of the growth of crystals in clusters, is not adequately predicted by existing models. As such, a new mass-to-frequency conversion model is proposed herein to explain the observed frequency inversions. This model is derived from a lumped element approach with point-contact loading and Mason equivalent circuit theory. Critically, the physical phenomena occurring form the basis of the model, particularly addressing the three sources of impedance. When a crystal nucleates and grows, its inertial impedance is considered along with a Kelvin–Voigt link with a hydration layer. A comparison between the proposed model and experimental data, of both frequency and dissipation data for the first four harmonics, shows good agreement for the supersaturations (S = C/C*) of S = 3.75, S = 3.48, and S = 3.22. Additionally, significant improvements over existing models for the case of surface crystallization are observed. The proposed model was therefore able to explain that frequency inversions are caused by a shift from inertia-dominated to elastic-dominated impedance, occurring as a result of crystal growth. Using the nucleation induction time and nucleation rates, determined with imaging, an additional understanding of the crystals’ mechanical properties (stiffness and dampening) was obtained.
Campbell KLS, Lapidot T, Williams DR, 2015, Foaming of CO2-loaded amine solvents degraded thermally under stripper conditions, Industrial & Engineering Chemistry Research, Vol: 54, Pages: 7751-7755, ISSN: 1520-5045
Foaming of amine solutions remains a problem for natural gas sweetening and post-combustion carbon capture. New amine-based solutions are being developed to replace monoethanolamine (MEA). This work tested the foaminess of MEA and three alternatives (methyldiethanolamine (MDEA), 1-(2-aminoethyl)piperazine (AEPZ), and 2-amino-2-methyl-1-propanol (AMP)) before and after thermal degradation; two methods were used to describe the foaminess. Foam was only formed after thermal degradation. The first method suggests foaminess, where AEPZ > MDEA > MEA; AMP, by contrast, did not conform to this model and formed a stable foam. The second method, using liquid physical properties, found that solutions that contained more degradation products (MEA, MDEA, AMP) showed different foaminess than those that did not (i.e., changing the chemistry during degradation strongly impacts the foaminess, which is observed). The foaming of these degraded samples demonstrates complexity that cannot be replicated by simple model solutions. Therefore, this study is more representative of the foaming behavior that is observed in industrial cases.
Sedransk KL, Fisher AC, Moggridge GD, 2015, Development of porous thin film polymers using metathetic etching on block copolymers, Materials Letters, Vol: 145, Pages: 299-303, ISSN: 1873-4979
The use of a metathetic catalytic reaction in the degradation of block copolymers is an important opportunity to develop varying porous structures using a one-pot method. In a non-solvent system, the 2nd Generation Grubbs’ catalyst etches alkene containing polymers. The structural integrity of the system is maintained over relatively short time periods. This allows the degradation of the alkene component whilst maintaining the microstructure. Catalytic control leads to porous structures of varying size, density, and distribution. This method is demonstrated on backed thin films, resulting in varying porosities. Pore density and regularity is enhanced by decreasing the film thickness to improve mass transfer of the catalyst through the polymer and increase stability from the supportive backing.
Sedransk KL, McGregor J, Mitchell J, et al., 2013, Towards Tailored Porous Polymers Using Solvent Effects in Catalytic Degradation, MACROMOLECULAR MATERIALS AND ENGINEERING, Vol: 298, Pages: 1344-1349, ISSN: 1438-7492
Sedransk KL, Kaminski CF, Hutchings LR, et al., 2011, The metathetic degradation of polyisoprene and polybutadiene in block copolymers using Grubbs second generation catalyst, POLYMER DEGRADATION AND STABILITY, Vol: 96, Pages: 1074-1080, ISSN: 0141-3910
Sedransk KL, Moggridge GD, 2010, Creating porous block copolymers using ADMET depolymerization mechanisms
Sedransk KL, Tenhaeff WE, Gleason KK, 2010, Grafting CVD of Poly(vinyl pyrrolidone) for Durable Scleral Lens Coatings, CHEMICAL VAPOR DEPOSITION, Vol: 16, Pages: 23-28, ISSN: 0948-1907
Martin TP, Sedransk KL, Chan K, et al., 2007, Solventless surface photoinitiated polymerization: Grafting chemical vapor deposition (gCVD), MACROMOLECULES, Vol: 40, Pages: 4586-4591, ISSN: 0024-9297
Martin TP, Kooi SE, Chang SH, et al., 2007, Initiated chemical vapor deposition of antimicrobial polymer coatings, BIOMATERIALS, Vol: 28, Pages: 909-915, ISSN: 0142-9612
Sedransk KL, Grande-Allen KJ, Vesely I, 2002, Failure mechanics of mitral valve chordae tendineae., J Heart Valve Dis, Vol: 11, Pages: 644-650, ISSN: 0966-8519
BACKGROUND AND AIM OF THE STUDY: Rupture of chordae tendineae is the main cause of mitral valve insufficiency, and often requires corrective surgery. The precise mechanisms of chordal rupture, however, are unknown. METHODS: Failure mechanics were measured in porcine mitral valve chordae (37 anterior marginal, 40 anterior basal, 35 posterior marginal, and 38 posterior basal). Full-length chordae were weighed, measured, and stretched to failure in an Instron tensile testing machine. The ruptured ends were characterized under a dissecting microscope. RESULTS: Marginal chordae had 68% thinner cross-sectional areas and failed at 68% less load and 28% less strain than basal chordae. Chordae from the posterior leaflet were 35% thinner and failed at 43% less load and 22% less strain than anterior leaflet chordae. Failure strength was lowest for posterior marginal chordae. Chordae most frequently tore just below the leaflet insertion, in what was often their narrowest section. CONCLUSION: Overall, the marginal chordae and posterior leaflet chordae were thinner and required less strain and load to fail than basal chordae and anterior leaflet chordae, respectively. These results support previous reports of decreased extensibility in marginal chordae. The high incidence of ruptures in the posterior marginal chordae of diseased mitral valves may be due to an inherent weakness in these chordae.
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