Investigation of the evaporation process of liquefied hydrocarbons in front of a compressor

International audienceInlet fogging and wet compression are well known methods to lower the inlet temperature of air compressors of gas turbines and in this way lead to a more efficient compression process. Injection of water into the gas stream is another established method to reduce the compressor stage inlet temperature during the compression of crack gas. The lower inlet temperature of the compressor stage reduces its power demand and additionally, the discharge temperature remains in a suitable range. Applying the method of liquid injection, all injected droplets should be evaporated before entering the compressor impeller to avoid damage at the blades. A good knowledge about the evaporation process of injected liquid in a free stream is necessary to determine the required distance for complete evaporation of all droplets. The aim of this paper is to provide clear statements on technical possibilities and requirements for an optimized and reliable compression process under liquid injection. The evaporation process of injected hydrocarbon droplets into a gas stream is investigated under realistic boundary conditions. Using conservation laws of mass and energy, a 1D numerical model is derived which allows the calculation of the liquid hydrocarbon evaporation in a free stream. The required fluid properties are taken from the National Institute of Standards and Technology (NIST). A comparison between the 1D model and a 3D Navier-Stokes solution for injected CH 4 droplets into a CH 4 gas stream shows good agreement regarding the decrease of the droplet diameter during the evaporation with respect to the amount of injected mass of liquid fluid and gives a good indication of the requested distance for complete evaporation. In addition, the 1D model predicts the temperature decrease of the gas during evaporation in good accordance to a 3D Navier-Stokes solver. Applying the simple 1D model, it is possible to evaluate the thermodynamic inlet parameters of a compressor for given boundary conditions quickly. In addition, the results allow a statement regarding the complete evaporation of all sizes of injected droplets at the compressor inlet and the formation of liquid films at the walls

Timing of eclogite-facies metamorphism of the Chuacús complex, Central Guatemala: Record of Late Cretaceous continental subduction of North America's sialic basement

A Late Cretaceous collision of the southernmost portion of the North American continental margin with an undetermined southern block was first established based on the sedimentation history of the plate's supracrustal cover, which is overthrust by harzburgite-dominated nappes of the Guatemala Suture Complex. The collision is also well registered in the metamorphic evolution of continental eclogites of the Chuacús complex, a geologic unit that represents Mesoproterozoic–Triassic sialic basement of North America at the boundary with the Caribbean plate. Garnet–clinopyroxene–phengite thermobarometry of eclogites hosted in Chuacús gneisses indicates near ultra-high-pressure conditions to ~ 700 °C and ~ 2.1–2.4 GPa. SHRIMP-RG U–Pb dating of eclogite metamorphic zircon yielded a 75.5 ± 2 Ma age (95% confidence level). Chondrite-normalized rare-earth element patterns of zircon lack Eu anomalies and show depletions in heavy rare earths, consistent with zircon growing in a plagioclase-free, garnet-rich, eclogite-facies assemblage. Additionally, a Sm–Nd clinopyroxene-two garnet–whole rock isochron from an eclogite band yielded a less precise but consistent age of 77 ± 13 Ma. The above features imply subduction to > 60 km depth of at least a portion of the North American sialic basement during Late Cretaceous collision. The Chuacús complex was overprinted by an amphibolite-facies event. For instance, mafic high-pressure paragneiss contains symplectite, resorbed garnet, and amphibole + plagioclase poikiloblasts. Zircon rims from the paragneiss sample show rare-earth patterns consistent with plagioclase growth and garnet breakdown. Their 74.5 ± 3.5 Ma SHRIMP-RG U–Pb age is therefore interpreted as the time of retrogression, which is consistent with previously published results. Within error, the ages of the eclogite-facies event and the amphibolite-facies retrogression are equivalent. Thus exhumation of the Chuacús slab from mantle to mid-crustal depth was quick, taking few million years. During exhumation, partial melting of Chuacús gneisses generated ubiquitous pegmatites. One of the pegmatites intruded the North Motagua mélange, which is a serpentinite-rich subduction complex of the Guatemala Suture Complex containing Early Cretaceous oceanic eclogites. U–Pb, Rb–Sr, and K–Ar ages of the pegmatite range ~ 76–66 Ma. Thus initial juxtaposition of continental and oceanic high-pressure belts of the Guatemala Suture Complex predates Tertiary–present strike-slip faulting between the North-American and Caribbean plates

Jadeitite formed during subduction: In situ zircon geochronology constraints from two different tectonic events within the Guatemala Suture Zone

Jadeitite is a rare rock type associated with high-pressure–low-temperature blocks within serpentinite matrix mélanges. Models of formation involve precipitation from subduction-zone aqueous fluids veining the overlying mantle wedge (P-type), or metasomatism of igneous and/or sedimentary protoliths previously emplaced into the mélange (R-type). Age determinations of mélange lithologies provide constraints on the timing of “peak metamorphism” and subsequent exhumation. The timing of jadeitite formation, particularly in the rich source of the Guatemala Suture Zone (GSZ), is a controversial subject needing further attention. Over 80 in situ zircon crystals from three jadeitites and two mica–albite rocks from the North Motagua Mélange and one phengite jadeitite from the South Motagua Mélange of the GSZ were studied for age and trace-element determination. Most of these zircons are characterized by low Th/U ratios, depleted chondrite-normalized REE patterns relative to zircons from oceanic gabbros, and contain fluid and mineral inclusions that reflect the primary mineralogy (i.e., jadeite) and context (i.e., crystallization from an aqueous fluid) of the host rock, and thus formed during jadeitite crystallization. The SHRIMP-RG and LAM-ICP-MS U–Pb dates from zircon indicate that jadeitites and mica–albite rocks from the GSZ were formed through vein precipitation at ~98−80 and ~154–158 Ma, respectively. These data show (a) older ages that indicate jadeitite crystallization occurred ~10–30 Ma before the preserved subduction-zone peak metamorphism (e.g., exhumed eclogite), and (b) a second group of ages slightly younger than, or similar to, exhumation ages given by Ar–Ar dates from micas. Similar relationships occur at other jadeitite occurrences, such as the Syum-Keu ultramafic complex in the Polar Urals (Russia) and the serpentinite mélanges of the Río San Juan complex (Dominican Republic). The data argue for formation of jadeitite within the mantle wedge during active subduction. Thus, jadeitite provides a record of fluid introduction into the mantle wedge during subduction rather than during exhumation

PETROGRAPHIC CHARACTERIZATION, GEOCHEMISTRY AND AGE OF THE SAN JOSÉ DEL GUAVIARE NEPHELINE SYENITE.

Las rocas de la Sienita Nefelínica de San José del Guaviare se presentan como dos cuerpos a unos 20 km al SW del municipio San José del Guaviare. Vesga y Castillo (1972) reportan el primero de ellos en la vereda La Pizarra, otro cuerpo del cual no se tenían referencias bibliográficas aparece en la vereda Las Delicias. Petrográficamente las rocas son sienitas nefelínicas, monzosienitas nefelínicas y granofels de feldespato y nefelina constituidas por microclina, nefelina, plagioclasa ± biotita ± arfvedsonita como minerales principales y como minerales accesorios fluorita, esfena, apatito, granate, circón, epidota y calcita. Las rocas presentan un carácter mixto de texturas y estructuras ígneas en el cuerpo La Pizarra y metamórficas heredadas (restitas) que predominan en el cuerpo Las Delicias, permitiendo sugerir un ambiente de formación a partir de procesos de anatexia. Las rocas geoquímicamente muestran una naturaleza alcalina, localizándose dentro del campo de rocas formadas en ambiente de intraplaca.Se determinó por los métodos U/Pb en circón y 40Ar/39Ar (HS) en biotita una edad de 577.8 ± 6.3 - 9 Ma (Ediacaran) de cristalización y 494±5 Ma (Furoginiano) de enfriamiento. Palabras clave: Sienita nefelínica, San José del Guaviare, Anatexia, Alcalino.      The San José del Guaviare Nepheline Syenite includes two rock bodies that crop out 20 km SW of the town with the same name. The first of these bodies, which had already been reported by Vesga and Castillo (1972), is exposed in the La Pizarra area. The second body, which had not been previously reported, occurs in the Las Delicias area.Petrographic characterization shows that rocks correspond to nepheline syenite, nepheline monzosyenite, and feldspar + nepheline granofels. The main minerals in the rocks are microcline + nepheline + plagioclase ± biotite ± arfvedsonite, and accessory phases include fluorite, sphene, apatite, garnet, zircon, epidote and calcite. Structures and textures are chiefly igneous in the la Pizarra body and mainly metamorphic (restitic) in the Las Delicias body. The geochemical character of the rocks is alkaline, and they correspond to within- the field of rocks formed in intraplate environment. The above features suggest that the San José del Guaviare syenite was formed by anatexis in a continental environment.U/Pb dating of zircon and 40Ar/39Ar (HS) dating of biotite indicates age 577.8± 6.3 - 9 Ma (Ediacaran) crystallization and 494±5 Ma (late Cambrian) cooling. Keywords: Nepheline syenite, San José del Guaviare, Anatexis, Alkaline magmas. &nbsp

PETROGRAPHIC CHARACTERIZATION, GEOCHEMISTRY AND AGE OF THE SAN JOSÉ DEL GUAVIARE NEPHELINE SYENITE.

Las rocas de la Sienita Nefelínica de San José del Guaviare se presentan como dos cuerpos a unos 20 km al SW del municipio San José del Guaviare. Vesga y Castillo (1972) reportan el primero de ellos en la vereda La Pizarra, otro cuerpo del cual no se tenían referencias bibliográficas aparece en la vereda Las Delicias. Petrográficamente las rocas son sienitas nefelínicas, monzosienitas nefelínicas y granofels de feldespato y nefelina constituidas por microclina, nefelina, plagioclasa ± biotita ± arfvedsonita como minerales principales y como minerales accesorios fluorita, esfena, apatito, granate, circón, epidota y calcita. Las rocas presentan un carácter mixto de texturas y estructuras ígneas en el cuerpo La Pizarra y metamórficas heredadas (restitas) que predominan en el cuerpo Las Delicias, permitiendo sugerir un ambiente de formación a partir de procesos de anatexia. Las rocas geoquímicamente muestran una naturaleza alcalina, localizándose dentro del campo de rocas formadas en ambiente de intraplaca.Se determinó por los métodos U/Pb en circón y 40Ar/39Ar (HS) en biotita una edad de 577.8 ± 6.3 - 9 Ma (Ediacaran) de cristalización y 494±5 Ma (Furoginiano) de enfriamiento. Palabras clave: Sienita nefelínica, San José del Guaviare, Anatexia, Alcalino.      The San José del Guaviare Nepheline Syenite includes two rock bodies that crop out 20 km SW of the town with the same name. The first of these bodies, which had already been reported by Vesga and Castillo (1972), is exposed in the La Pizarra area. The second body, which had not been previously reported, occurs in the Las Delicias area.Petrographic characterization shows that rocks correspond to nepheline syenite, nepheline monzosyenite, and feldspar + nepheline granofels. The main minerals in the rocks are microcline + nepheline + plagioclase ± biotite ± arfvedsonite, and accessory phases include fluorite, sphene, apatite, garnet, zircon, epidote and calcite. Structures and textures are chiefly igneous in the la Pizarra body and mainly metamorphic (restitic) in the Las Delicias body. The geochemical character of the rocks is alkaline, and they correspond to within- the field of rocks formed in intraplate environment. The above features suggest that the San José del Guaviare syenite was formed by anatexis in a continental environment.U/Pb dating of zircon and 40Ar/39Ar (HS) dating of biotite indicates age 577.8± 6.3 - 9 Ma (Ediacaran) crystallization and 494±5 Ma (late Cambrian) cooling. Keywords: Nepheline syenite, San José del Guaviare, Anatexis, Alkaline magmas. &nbsp

Orientation dependence of thermal and mechanical hysteresis in Ni51Fe18Ga27Co4 single crystals

The orientation dependence of thermal ΔТ and mechanical Δσ hysteresis was investigated in Ni51Fe18Ga27Co4 single crystals as-grown with isobaric (shape memory effect) and isothermal (superelasticity) experiments. Single crystals oriented along the [001]-direction show a high reversible deformation of 001 ЭПФ ε = (4,0 ± 0,2) % for martensitic transformations, small thermal hysteresis ΔТ = (22 ± 2) K and mechanical Δσ001 = (47 ± 2) МПа hysteresis, as compared with to single crystals oriented along the [110]-direction. Such orientation dependence is determined by the contribution of the L10-martensite under the εdetw in deformation of transformation

Terrenos, complejos y provincias en la cordillera central de Colombia

The Central Cordillera of Colombia consists of several tectonostratigraphic terrains that have not been fully recognized yet. To the east of San Jerónimo Fault are found the Chibcha, Tahamí, Panzenú (Puquí) and Anacona (Caldas) terrains with continental basement, and between the Romeral and the Cauca fault systems the Quebradagrande, Amagá-Sinifaná, Heliconia and Arquía terranes, mostly oceanic, are found. The Chibcha terrain is formed by a Grenvillian basement covered by Lower Paleozoic sediments that suffered a slight metamorphism, while in the Tahamí the metamorphism is Late Permian to Triassic, indicating that it was formed within the collision zone of Pangea but rather in the Paleopacific margin of Pangea as part of the Terra Australis Orogen. The metamorphism in the Panzenú Terrain is somewhat older, Carboniferous. The Anacona Terrain presents Devonian metamorphism and was not affected by the Triassic metamorphism that affected the Tahamí, indicating that it had not been amalgamated yet during the Triassic orogeny. A number of narrow belts of allochtonous rocks were accreted after Mid-Cretaceous times to the Tahamí Terrane which are from east to west: the Quebradagrande Complex, the Sinifaná low-grade metasedimentary rocks and the Amagá Granite (Amagá-Sinifaná Terrane), the ophiolitic rocks of Heliconia and the Arquía Complex. All of them are located between the systems of faults Cauca and Romeral.La Cordillera Central de Colombia está compuesta por varios terrenos tectonoestratigráficos que no han sido aún bien reconocidos. Al este de la Falla San Jerónimo se encuentran terrenos continentales como los terrenos Chibcha, Tahamí, Panzenú (Puquí) y Anacona (Caldas), mientras que entre los sistemas de Falla de Romeral y de Cauca se encuentran los terrenos Quebradagrande, Amagá-Sinifaná, Heliconia y Arquía, predominantemente de carácter oceánico. El terreno Chibcha incluye un basamento grenvilliano con sedimentos del Paleozoico Inferior, que sufrieron un leve metamorfismo, mientras que el metamorfismo del terreno Tahamí parece ser Pérmico muy tardío a Triásico, evidenciando que se formó en la margen paleopacífica de Pangea, como parte del orógeno de Terra Australis, más bien que en la zona de colisión continental.  El terreno Panzenú sufrió un metamorfismo Carbonífero, anterior al del Tahamí. El terreno Anacona presenta edades de metamorfismo Devónicas y no fue afectado por el metamorfismo Triásico, indicando que aún no se había amalgamado al terreno Tahamí durante la orogenia Triásica. Un conjunto de delgadas franjas alóctonas parece haberse amalgamado después del Cretáceo Medio al Tahamí, y está constituido de oriente a occidente por las rocas del Complejo Quebradagrande, las Metasedimentitas de Sinifaná y el Stock de Amagá (terreno Amagá- Sinifaná), las rocas ofiolíticas de Heliconia y las rocas metamórficas del Complejo Arquía. Todas ellas se encuentran localizadas entre los sistemas de fallas Cauca y Romeral