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- Ali Motamed, Mohammad, et al.
(författare)
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Part-load thermal efficiency enhancement in gas turbine combined cycles by exhaust gas recirculation
- 2024
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Ingår i: Applied Thermal Engineering. - 1359-4311. ; 244
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Tidskriftsartikel (refereegranskat)abstract
- Gas turbine power plants are popular for offshore power generation due to high power density and their reliability. However, growing usage of renewable energies put gas turbines in a load following backup operation. These power plants suffer part-load efficiency losses when operating at less than full capacity, resulting in higher carbon dioxide (CO2) emission from natural gas combined cycles or higher consumption of carbon-free fuels in decarbonized gas turbines. In this article, a solution is proposed for enhancement of power plant part-load thermal efficiency based on exhaust gas recirculation in the gas turbine cycle. Recirculating exhaust gas into the gas turbine have been studied by several researchers and engineers due to its benefit for carbon-free combustion and carbon capture mechanisms. The proposed operation strategy is evaluated for single-spool and two-spool gas turbines operating jointly with a steam bottoming cycle harvesting the waste heat for further power production. In the suggested strategy, eliminating the necessity to cool down the recirculated gas resulted in less equipment footprint for the power plant which makes it more favorable for offshore applications. An in-house design and simulation tool is developed for evaluating gas turbines with modern gas recirculating systems and a flexibility in operation with carbon-free fuel mixtures. The enhancement in efficiency boost, emission reduction, and fuel consumption is quantified demonstrating the improvements with the proposed solution.
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| 3. |
- Couch, Fergus J., et al.
(författare)
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Identification of four novel susceptibility loci for oestrogen receptor negative breast cancer
- 2016
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11375, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 x 10(-8)) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for similar to 11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction.
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| 4. |
- Csenki, Leonard, et al.
(författare)
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Proof of principle of a generalized fuzzy Hough transform approach to peak alignment of one-dimensional 1H NMR data
- 2007
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 389:3, s. 875-885
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Tidskriftsartikel (refereegranskat)abstract
- In metabolic profiling, multivariate data analysis techniques are used to interpret one-dimensional (1D) 1H NMR data. Multivariate data analysis techniques require that peaks are characterised by the same variables in every spectrum. This location constraint is essential for correct comparison of the intensities of several NMR spectra. However, variations in physicochemical factors can cause the locations of the peaks to shift. The location prerequisite may thus not be met, and so, to solve this problem, alignment methods have been developed. However, current state-of-the-art algorithms for data alignment cannot resolve the inherent problems encountered when analysing NMR data of biological origin, because they are unable to align peaks when the spatial order of the peaks changes—a commonly occurring phenomenon. In this paper a new algorithm is proposed, based on the Hough transform operating on an image representation of the NMR dataset that is capable of correctly aligning peaks when existing methods fail. The proposed algorithm was compared with current state-of-the-art algorithms operating on a selected plasma dataset to demonstrate its potential. A urine dataset was also processed using the algorithm as a further demonstration. The method is capable of successfully aligning the plasma data but further development is needed to address more challenging applications, for example urine data.
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| 6. |
- Mocholí Montañés, Rubén, 1990, et al.
(författare)
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Demonstrating load-change transient performance of a commercial-scale natural gas combined cycle power plant with post-combustion CO2 capture
- 2017
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 63, s. 158-174
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Tidskriftsartikel (refereegranskat)abstract
- The present work aims to study the transient performance of a commercial-scale natural gas combined cycle (NGCC) power plant with post-combustion CO2 capture (PCC) system via linked dynamic process simulation models. The simulations represent real-like operation of the integrated plant during load change transient events with closed-loop controllers. The focus of the study was the dynamic interaction between the power plant and the PCC unit, and the performance evaluation of decentralized control structures. A 613 MW three-pressure reheat NGCC with PCC using aqueous MEA was designed, including PCC process scale-up. Detailed dynamic process models of the power plant and the post-combustion unit were developed, and their validity was deemed sufficient for the purpose of application. Dynamic simulations of three gas turbine load-change ramp rates (2%/min, 5%/min and 10%/min) showed that the total stabilization times of the power plant's main process variables are shorter (10–30 min) than for the PCC unit (1–4 h). A dynamic interaction between the NGCC and the PCC unit is found in the steam extraction to feed the reboiler duty of the PCC unit. The transient performance of five decentralized PCC plant control structures under load change was analyzed. When controlling the CO2 capture rate, the power plant performs in a more efficient manner at steady-state part load; however, the PCC unit experiences longer stabilization times of the main process variables during load changes, compared with control structures without CO2 capture rate being controlled. Control of L/G ratio of the absorber columns leads to similar part load steady-state performance and significantly faster stabilization times of the power plant and PCC unit's main process variables. It is concluded that adding the PCC unit to the NGCC does not significantly affect the practical load-following capability of the integrated plant in a day-ahead power market, but selection of a suitable control structure is required for efficient operation of the process under steady-state and transient conditions.
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