KINETIC ANALYSIS OF METHANE HYDRATE FORMATION WITH BUTTERFLY TURBINE IMPELLERS

Heat generation during gas hydrate formation is an important problem because it reduces the amount of water and gas that become gas hydrates. In this research work, we present a new design of an impeller to be used for hydrate formation and to overcome this concern by following the hydrodynamic literature. CH4 hydrate formation experiments were performed in a 5.7 L continuously stirred tank reactor using a butterfly turbine (BT) impeller with no baffle (NB), full baffle (FB), half baffle (HB), and surface baffle (SB) under mixed flow conditions. Four experiments were conducted separately using single and dual impellers. In addition to the estimated induction time, the rate of hydrate formation, hydrate productivity and hydrate formation rate, constant for a maximum of 3 h, were calculated. The induction time was less for both single and dual-impeller experiments that used full baffle for less than 3 min and more than 1 h for all other experiments. In an experiment with a single impeller, a surface baffle yielded higher hydrate growth with a value of 42 108 mol/s, while in an experiment with dual impellers, a half baffle generated higher hydrate growth with a value of 28.8 108 mol/s. Both single and dual impellers achieved the highest values for the hydrate formation rates that were constant in the full-baffle experiments

Gas hydrate technology: state of the art and future possibilities for Europe

Interest in natural gas hydrates has been steadily increasing over the last few decades, with the understanding that exploitation of this abundant unconventional source may help meet the ever-increasing energy demand and assist in reduction of CO2 emission (by replacing coal). Unfortunately, conventional technologies for oil and gas exploitation are not fully appropriate for the specific exploitation of gas hydrate. Consequently, the technology chain, from exploration through production to monitoring, needs to be further developed and adapted to the specific properties and conditions associated with gas hydrates, in order to allow for a commercially and environmentally sound extraction of gas from gas hydrate deposits. Various academic groups and companies within the European region have been heavily involved in theoretical and applied research of gas hydrate for more than a decade. To demonstrate this, Fig. 1.1 shows a selection of leading European institutes that are actively involved in gas hydrate research. A significant number of these institutes have been strongly involved in recent worldwide exploitation of gas hydrate, which are shown in Fig. 1.2 and summarized in Table 1.1. Despite the state of knowledge, no field trials have been carried out so far in European waters. MIGRATE (COST action ES1405) aims to pool together expertise of a large number of European research groups and industrial players to advance gas-hydrate related activity with the ultimate goal of preparing the setting for a field production test in European waters. This MIGRATE report presents an overview of current technologies related to gas hydrate exploration (Chapter 2), production (Chapter 3) and monitoring (Chapter 4), with an emphasis on European activity. This requires covering various activities within different disciplines, all of which contribute to the technology development needed for future cost-effective gas production. The report points out future research and work areas (Chapter 5) that would bridge existing knowledge gaps, through multinational collaboration and interdisciplinary approaches

Natural gas hydrates as a cause of underwater landslides: A review

Natural gas hydrates occur worldwide in polar regions, normally associated with onshore and offshore permafrost, and in sediment of outer continental margins. The total amount of methane in gas hydrates likely doubles the recoverable and non-recoverable fossil fuels. Three aspects of gas hydrates are important: their fossil fuel resource potential, their role as a submarine geohazard, and their effects on global climate change. Since gas hydrates represent huge amounts of methane within 2000 m of the Earth's surface, they are considered to be an unconventional, unproven source of fossil fuel. Because gas hydrates are metastable, changes of pressure and temperature affect their stability. Destabilized gas hydrates beneath the seafloor lead to geologic hazards such as submarine slumps and slides. Destabilized gas hydrates may also affect climate through the release of methane, a "greenhouse" gas, which may enhance global warming

Effect of carbon dioxide on PVT behavior of geothermal fluids and prevention of calcite deposition by inhibitor injection

Ph.D. - Doctoral Progra

Evolution of Balcova Geothermal District Heating System Turkey

Balçova geothermal field is located in a densely populated area which makes direct heat applications very efficient and economical. Heat produced from Balçova geothermal field is utilized for three main purposes: greenhouse heating, balneology and residential heating. Among these three applications, the latter one is the main application throughout the Balçova Geothermal District Heating System (BGDHS). The field produces hot water from two different horizons: one shallow and one deeper zone. This paper presents the encountered problems and their solution strategies while expanding the system to the current state of 35,000 residence equivalent capacity (lresidence equivalent = 100 m2 heated area)

Evaluation of Geothermal District Heating Systems of Turkey

Turkey is one of the few countries that has almost all possible applications of geothermal energy. Geothermal district heating has a relatively short history (since 1987) compared to other direct utilization but plays important economic, social and environmental roles in some towns. There are 18 geothermal district heating systems (GDHS), mainly in the Aegean region with resource temperatures between 57–145C. Current heating capacities of those systems are in the range of 570 to 37500 Residence Equivalent (RE, 1 RE= 100 m2 heated area). This paper evaluates each GDHS on their technical characteristics, then gives details about three GDHS and compares the economics of district heating applications based on alternative fuel prices

Yüzey aktif maddeler ve polimerler kullanılarak doğal gaz hidrat oluşumunun engellenmesi

TÜBİTAK YDABÇAG1.11.2001Petrol endüstrisi her geçen gün daha derin deniz diplerindeki alanlarla ilgilenmekte ve üretilen akışkanların yüksek basınç ve düşük sıcaklık ortamlarında kalma süreleri artmaktadır. Bu şartlar altında boru hattında hidrat oluşum tehlikesi artmaktadır. Uzun yıllardan beri, termodinamik hidrat engelleyiciler (metanol, gliserol vb.) hidrat oluşumunu engellemek için kullanılmaktadır. fakat bu engelleyiciler derin okyanus diplerinde kullanımlarında bazı dezavantajlar göstermektedir. Çok yüksek miktarlarda kullanılmaları gerekmekte (yaklaşık ağırlıkça % 20-40) ayrıca pahalı ve çevre açısından zararlı kimyasallardır. Bu nedenle, teni tip kimyasalların; örneğin kinetik engelleyicilerin (polimerler ve yüzey aktif maddeler) bulunması hayati önem taşımaktadır. Bu yeni kimyasallar çok düşük miktarlarda kullanılırlar(ağırlıkça % 1'den az) ve çevre dostu kimyasallardır. Halihazırda petrol endüstrisinde birçok kinetik engelleyici mevcut olmasına rağmen, bunlar patent altındadır ve bu maddeler hakkındaki açık olan bilgiler sınırlıdır. Bundan dolayı yeni tip engelleyicilerin bilimsel çalışmalar ve endüstri arenası için bulunması zorunludur. Bu çalışmada, polimer ve yüzey aktif maddelerin sulu çözeltileri ile metan hidratının oluşum şartları ve kinetiği deneysel olarak çalışıldı. Bu çalışmanın ana amacı test edilen polimerler ve yüzey aktif maddeler arasından en iyi kinetik metan hidratı engelleyicisini tesbit etmektir. Bu amaç için yüksek basınç metan hidrat oluşum sistemikuruldu ve yüzey aktif maddeler ve polimerlerden oluşan oniki kimyasal test edildi.Hidrat engelleyici olarak bilinen ve patent altındaki polivinil pirolidone(PVP) hem deney yönteminin doğruluğunu kanıtlamak hem de diğer test edilen kimyasalların etkilerini kıyaslamak için referans kimyasal olarak kullanıldı. İyonik olmayan suda çözünen termoplastik olan poli (2-etl-2oksazolin) (PEO) en iyi hidrat engelleyici olarak tesbit edildi. PVP'nin gösterdiği davranışı gösteren PEO'nun en düşük ağırlıkça % 0.1 derişiminde etkili bir hidrat engelleyici olduğu saptandı. Çalışılan şartlar altında PEO metan hidratı oluşumunu 60 dakikadan daha fazla bir sürede geciktirmekte ve bu süreden sonrs da hidrat oluşum hızı safsu ile yapılan deneyin hidrat oluşum hızına kıyasla çok düşüktür