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Algorytm prognozowania i optymalizacji kosztów sprężania gazu podczas eksploatacji PMG

Kwilosz T.

Nafta-Gaz

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2018

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R. 74, nr 12

938--943

PL

W ostatnich latach wszystkie podziemne magazyny gazu zostały wyposażone w stacje sprężania po stronie odbioru gazu. Pozwoliło to zwiększyć pojemność czynną magazynu i poprawić jego eksploatację w szerszym zakresie ciśnień. Wadą takiego rozwiązania jest wzrost kosztów magazynowania gazu. W celu zminimalizowania kosztów sprężania gazu można zastosować odpowiednio opracowany dla zainstalowanego układu sprężania gazu program eksploatacji PMG. W artykule zaprezentowano algorytm pozwalający na optymalizację pracy podziemnego magazynu gazu w celu obniżenia kosztów sprężania gazu. Metoda optymalizacyjna została opracowana dla fazy odbioru gazu z PMG, podczas której zastosowano jego sprężanie. Analityczny model odbioru gazu z PMG połączono z modelem sprężania gazu dostarczanego do systemu przesyłowego. Analizowaną funkcją celu jest sumaryczne zużycie energii przez sprężarkę podczas odbioru zadanej ilości gazu z PMG. Wynikiem zastosowanej metody jest ustalenie optymalnych parametrów odbioru i sprężania gazu. Dla ilustracji opracowanego algorytmu zamieszczono wyniki obliczeń rozwiązania zagadnienia optymalizacyjnego dla przykładowego PMG. Wykorzystano dane pochodzące z jednego z podziemnych magazynów gazu w Polsce (PMG-TEST). Rzeczywiste dane związane z parametrami pracy PMG-TEST oraz wartości dotyczące charakterystyki sprężarki zostały zaburzone w celu utrudnienia identyfikacji rzeczywistej instalacji magazynowej i nieuprawnionego wykorzystania danych. Obliczenia wykonano przy użyciu arkuszy kalkulacyjnych Ms Excel. Algorytm jest prosty w zastosowaniu i daje, po uprzednim skalibrowaniu, możliwość szybkiego wyznaczenia optymalnego trybu pracy sprężarek na dowolnej instalacji magazynowania gazu. W ostatnich latach nastąpił rozwój prac dotyczących automatycznego przetwarzania danych związanych z eksploatacją PMG. Mimo to podczas eksploatacji polskich magazynów gazu nie wykorzystuje się systemów informatycznych optymalizujących koszty pracy stacji sprężania gazu. Opracowana metoda jest odpowiedzią na liczne pytania instytucji zajmujących się magazynowaniem gazu, dotyczące optymalizacji kosztów magazynowania gazu, w tym kosztu wykorzystania urządzeń sprężających.

EN

At present, all underground gas storage facilities are equipped with gas compression stations. The gas compression station allows to increase the UGS active volume and use storage in a wider range of pressure. Increase of the storage services cost is the main disadvantage of this solution. In order to minimize the gas compression costs, a UGS operation program, appropriately developed for the installed gas compression system, should be used. The article presents an algorithm for determining optimal exploitation of underground gas storage due to the minimal cost of gas compression. The optimization method was developed for the gas production phase during the winter season. During the withdrawal season gas is delivered to the transmission system by using a compression station. An analytical model of gas withdrawn from a UGS combined with a model of gas delivered by a compression station to the gas pipeline system was applied. Cost of the compression fuel used during the withdrawal season is the target function. The aim of the analyzed function is to minimize the cost of the compression fuel during the withdrawal and injection season. For illustration of the developed algorithm, the results of calculations of the optimization solution for the sample UGS are included. The calculations were made using Ms Excel spreadsheets equipped with an implemented optimization algorithm.

2

Compressor application for extending production life cycle in mature fields

Stefanescu D. P., Maulidani O. A., Audrey B.

AGH Drilling, Oil, Gas

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2016

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Vol. 33, no. 2

495--506

EN

Mature gas fields are subject to network backpressure fluctuation causing liquid loading condition. The liquid loading, theoretically, occurs when the gas velocity is below its critical velocity which commonly happens in mature fields when rates become “low”. Based on Turner or Coleman’s equations, the critical velocity is proportional to the wellhead flowing pressure. This means, when the wellhead pressure increases as the result of higher external (sales) pressure, then the critical velocity will be higher. This condition will give a “pseudo” production decline of the wells. Gas compression is among the best fit-for-purpose solution to overcome the above challenges. Gas compression will help to reduce the wellhead flowing pressure which increases the gas velocity above the critical velocity as well as the well gas rate by lowering the bottomhole flowing pressure. The wells will be capable of unloading the liquid inside the wellbore and the reservoir will suffer a higher pressure drawdown. Moreover, the wells will not be impacted by the external pressure fluctuation as long as this latter is below the compressor discharge pressure. Gas compression has been implemented in Laslau Mare mature gas field to extend the production life cycle. 5 wellhead compressors have been installed since 2010 and 1 group compressor since 2014. Both types of compressor show positive results. This paper explains the application of compressor in Laslau Mare field starting with candidate selection up to cash flow analysis. A big emphasis will be given to the compressor/ well performance.

3

Utilization of heat recovered from compressed gases in an oxy-combustion power unit to power the Organic Rankine Cycle module

Kotowicz J., Job M., Bartela Ł., Brzęczek M., Skorek-Osikowska A.

Journal of Power Technologies

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2015

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Vol. 95, nr 4

239--249

EN

Oxy-combustion technology is a zero-emission technology with great potential for commercial use in the near future. Application of this technology is linked with high energy losses in oxygen production and preparation of captured CO2 for transport to a storage place. In the analyzed oxy-combustion power plant with cryogenic air separation unit the compression of gases is responsible for most of the energy consumption. Compressed gases are sources of significant amounts of waste heat energy. Effective use of this energy is crucial to reducing the efficiency drop caused by additional installations. One method extensively examined in the literature for effective utilization of medium-grade and low-grade waste heat energy is the application of the Organic Rankine Cycle (ORC), which uses a low-boiling medium to produce additional electric power. The paper presents the results of analyses of the use of heat recovered from three sources identified in the oxy-combustion unit to power the ORC module. This includes heat from gases in the compression installations within the air separation unit, the CO2 processing unit and the CO2 compression installation. Thermodynamic and economic analyses were performed to assess the potential investment.

4

Analysis of the use of waste heat in the oxy-combustion power plant to replace the steam cycle heat regeneration

Job M., Bartela Ł., Skorek-Osikowska A.

Journal of Power Technologies

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2013

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Vol. 93, nr 3

133-141

EN

Oxy-combustion technology is based on the burning of fuel in an oxidant atmosphere with increased proportion of oxygen. By eliminating the nitrogen from the combustion process flue gas mainly consist of carbon dioxide and water vapor, allowing for the separation of CO2 from flue gas at a relatively low energy cost. Yet, production of high purity oxygen is bound with significant electricity consumption. The object of the analysis is a supercritical oxy-combustion coal-fired power plant. Auxiliary power demand is associated with the work of compressors in the cryogenic air separation unit and the installation of flue gas conditioning. The paper presents the results of thermodynamic analysis for different cases of compression installations organization extracted from individual blocks of the oxy-combustion unit. Analyzes were aimed to identify the potential for reducing energy consumption in the compression process by its appropriate organization and to define the energy potential of using the heat recovered in cooling and condensation in the individual sub-processes to replace the low-pressure regeneration.