A review of solidified natural gas (SNG) technology for gas storage via clathrate hydrates

Veluswamy, Hari Prakash,Kumar, Asheesh,Seo, Yutaek,Lee, Ju Dong,Linga, Praveen Elsevier 2018 APPLIED ENERGY Vol.216 No.-

<P><B>Abstract</B></P> <P>Natural gas (NG), the cleanest burning fossil fuel, plays a crucial role in meeting the global energy demand, contributing to 24% and is projected to grow at a rate of about 2% until 2040. Natural gas is also considered as the bridging fuel to transition into a carbon-constrained world with reduced carbon dioxide emissions whilst catering to the huge energy demand. Efficient and effective modes of NG storage/transport are dire need in the current golden era of natural gas. A plethora of advantages offered by storing NG in the form of hydrates carve a niche for this novel technology. Termed as solidified natural gas (SNG) technology, it has remarkable potential to store multi-fold volumes of natural gas in compact hydrate crystals offering the safest and the most environmental friendly mode of NG storage. This review provides an account on the research efforts put forth in this technology. Hydrate formation and storage aspects have been examined thoroughly with a subtle account on the gas recovery. The review encompasses studies conducted using different promoters (thermodynamic, kinetic or a combination of both) in different reactor configurations, novel/innovative approaches and hybrid processes adopted to improve the kinetics of hydrate formation and to increase the gas storage capacity. Detailed sections on the ‘self-preservation’ and ‘tuning’ effect in hydrates have been included due to their significance in SNG technology. Process chain of the SNG technology, underlying challenges and measures adopted to deploy the SNG technology for large-scale NG storage applications are included in this review.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First review on Solidified Natural Gas (SNG) Technology via clathrate hydrates. </LI> <LI> Prospects for improving the kinetics and storage capacity is presented. </LI> <LI> Critical examination of ‘self-preservation’ and ‘tuning’ effect in hydrates is presented. </LI> <LI> Challenges and future directives for commercial deployment of SNG technology are outlined. </LI> </UL> </P>

Pre-Operative Evaluation of Ovarian Tumors by Risk of Malignancy Index, CA125 and Ultrasound

Arun-Muthuvel, Veluswamy,Jaya, Vijayaraghavan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Purpose: To evaluate the diagnostic performances of risk of malignancy index (RMI), CA-125 and ultrasound score in differentiating between benign and borderline or malignant ovarian tumors and find the best diagnostic test for referral of suspected malignant ovarian cases to gynaecologic oncologists. Materials and Methods: This prospective study covered 467 women with pelvic tumors scheduled for surgery at our hospital between July 2011 and July 2013. The RMI was obtained from ultrasound score, CA125 and menopausal status. The diagnostic values of each parameter and the RMI were determined and compared using Statistical Packages for Social Sciences Version 14.0.1. Results: In our study, 61% of ovarian tumors were malignant in the post-menopausal age group. RMI with a cut-off 150 had sensitivity of 84% and specificity of 97% in detecting ovarian cancer. CA-125>30 had a sensitivity of 84% and a specificity of 83%. An ultrasound score more than 2 had a sensitivity of 96% and specificity of 81%. RMI had the least false malignant cases thus avoiding unnecessary laparotomies. Ultrasound when used individually had the best sensitivity but poor specificity. Conclusions: Our study has demonstrated the RMI to be an easy, simple and applicable method in the primary evaluation of patients with pelvic masses. It can be used to refer suspected malignant patients to be operated by a gynaecologic oncologist. Other models of preoperative evaluation should be developed to improve the detection of early stage invasive, borderline and non-epithelial ovarian cancers.

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

Kim, Hyunho,Veluswamy, Hari Prakash,Seo, Yutaek,Linga, Praveen The American Chemical Society 2018 CRYSTAL GROWTH AND DESIGN Vol.18 No.11

<P>In this study, we investigate the morphology of methane hydrate formation and growth in the presence of well-known thermodynamic inhibitors, monoethylene glycol (MEG) and methanol (MeOH) in a quiescent system. Morphology changes observed during the growth of methane hydrate while employing 5 wt % MEG and MeOH solutions in the presence and absence of NaCl are presented. When 5 wt % of MEG or MeOH was present in an aqueous solution individually, hydrate grew predominantly within the bulk solution featuring a “ridge”-shaped formation above the interface. In the presence of 3.5 wt % NaCl, an enhanced inhibition was observed for methane hydrates formed from 5 wt % MEG solution with limited hydrate growth in the bulk solution and above the gas-liquid interface. In contrast, 5 wt % MeOH solution in the presence of 3.5 wt % NaCl resulted in an increased hydrate growth in bulk (compared to the system without NaCl) and on the reactor wall above the gas-liquid interface, implying a weak promotion rather than the inhibition. Further, the effect of subcooling (Δ<I>T</I>) on the morphology of methane hydrates in the presence of MeOH/NaCl and MEG/NaCl was examined.</P><P>Morphology of methane hydrate formation observed in the presence of the well-known thermodynamic inhibitors, monoethylene glycol and methanol, individually (at 5 wt % concentration) and along with the presence of 3.5 wt % NaCl at the end of 24 h from nucleation in a quiescent system is presented.</P> [FIG OMISSION]</BR>

Mechanism of methane hydrate formation in the presence of hollow silica

Praveen Linga,Hari Prakash Veluswamy,Pinnelli Seetha Rama Prasad 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7

Methane hydrates are studied extensively as a prospective medium for storing and transporting natural gas due to their inherent advantages, including high volumetric energy storage density, being environmentally benign and extremely safe method compared to conventional compression and liquefaction methods. Enhanced formation kinetics of methane hydrates has been reported in hollow silica due to the increased gas/liquid contact surface area available for efficient conversion of water to hydrates. This work elucidates the mechanism of methane hydrate formation in light weight hollow silica. Hollow silica-to-water ratio was varied and its effect on the methane hydrate formation/dissociation morphology was observed. There exists a critical hollow silica-to-water ratio (1 : 6) beyond which the hydrates preferentially crystallize on the top of the bed by drawing water from the interstitial pores, whereas below this ratio the hydrate formation occurs within the bed between inter-particular spaces of hollow silica. Due to the very low bulk density, a small fraction of hollow silica was observed to be displaced from the bed during the hydrate formation above the critical hollow silica to water ratio.

Investigation of electrochemical capacitance of 18k nanoporous current collector incorporated MnO₂

Prabhin, V.S.,Jeyasubramanian, K.,Jeyaseeli Rashmi, I.,Hikku, G.S.,Veluswamy, Pandiyarasan,Cho, Byung Jin Elsevier 2018 Materials chemistry and physics Vol.220 No.-

<P><B>Abstract</B></P> <P>This paper deals with the fabrication of super capacitor electrode material employing a facile etching process followed by electrodeposition. Nanoporous gold current collector has been fabricated by chemically dealloying commercially available 18k gold having a composition of 74% Au, 24% Cu and 2% Ag, with dilute HNO<SUB>3</SUB> solution. Electrochemically deposited MnO<SUB>2</SUB> over the prepared porous Au electrode exhibits a very high specific capacitance value of 670 Fg<SUP>-1</SUP> which is about 1.65 times greater than that of MnO<SUB>2</SUB> coated over unetched Au electrode (407 Fg<SUP>-1</SUP>). Etched and unetched MnO<SUB>2</SUB> coated electrode materials are characterized using XRD, XPS, FESEM with EDAX and AFM. Electrochemical characterization of the obtained hybrid material is evaluated by running several cyclic voltagramms using electrochemical workstation. In contrast to the MnO<SUB>2</SUB> coated unetched Au hybrid electrode system, nanoporous AuMnO<SUB>2</SUB> electrode displays higher phase angle (79°) and lower time constant (2 ms) derived from the bode plot suggesting a better capacitance value. The high specific capacitances offered with good charge/discharge rates at a potential window of 0–0.8 V, in the scan rate of 100 mV/s for 1000 cycles, exhibiting high-energy storage density of 32.56 wh/kg and 53.6 wh/kg and power density of 366 w/kg and 603 w/kg for un-etched and etched electrodes respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MnO<SUB>2</SUB> is incorporated into porous and flat 18k Au substrates by bulk electrolysis. </LI> <LI> The MnO<SUB>2</SUB> depositions are characterized using XRD, XPS, FESEM, EDX mapping and AFM. </LI> <LI> Electrochemical analysis shows the high specific capacitance of the porous electrode. </LI> <LI> The impedance analysis suggests the superior characteristics of porous electrode. </LI> <LI> The prepared electrodes prove to be good candidate for high power applications. </LI> </UL> </P>

Targeted Resequencing of 30 Genes Improves the Detection of Deleterious Mutations in South Indian Women with Breast and/or Ovarian Cancers

Rajkumar, Thangarajan,Meenakumari, Balaiah,Mani, Samson,Sridevi, Veluswami,Sundersingh, Shirley Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

Background: We earlier used PCR-dHPLC for mutation analysis of BRCA1 and BRCA2. In this article we report application of targeted resequencing of 30 genes involved in hereditary cancers. Materials and Methods: A total of 91 patient samples were analysed using a panel of 30 genes in the Illumina HiScan SQ system. CLCBio was used for mapping reads to the reference sequences as well as for quality-based variant detection. All the deleterious mutations were then reconfirmed using Sanger sequencing. Kaplan Meier analysis was conducted to assess the effect of deleterious mutations on disease free and overall survival. Results: Seventy four of the 91 samples had been run earlier using the PCR-dHPLC and no deleterious mutations had been detected while 17 samples were tested for the first time. A total of 24 deleterious mutations were detected, 11 in BRCA1, 4 in BRCA2, 5 in p53, one each in RAD50, RAD52, ATM and TP53BP1. Some 19 deleterious mutations were seen in patients who had been tested earlier with PCR-dHPLC [19/74] and 5/17 in the samples tested for the first time, Together with our earlier detected 21 deleterious mutations in BRCA1 and BRCA2, we now had 45 mutations in 44 patients. BRCA1c.68_69delAG;p.Glu23ValfsX16 mutation was the most common, seen in 10/44 patients. Kaplan Meier survival analysis did not show any difference in disease free and overall survival in the patients with and without deleterious mutations. Conclusions: The NGS platform is more sensitive and cost effective in detecting mutations in genes involved in hereditary breast and/or ovarian cancers.