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Palou A.,Autonomous University of Barcelona | Miro A.,Autonomous University of Barcelona | Blanco M.,Autonomous University of Barcelona | Larraz R.,CEPSA Inc | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2017

Even when the feasibility of using near infrared (NIR) spectroscopy combined with partial least squares (PLS) regression for prediction of physico-chemical properties of biodiesel/diesel blends has been widely demonstrated, inclusion in the calibration sets of the whole variability of diesel samples from diverse production origins still remains as an important challenge when constructing the models. This work presents a useful strategy for the systematic selection of calibration sets of samples of biodiesel/diesel blends from diverse origins, based on a binary code, principal components analysis (PCA) and the Kennard-Stones algorithm. Results show that using this methodology the models can keep their robustness over time. PLS calculations have been done using a specialized chemometric software as well as the software of the NIR instrument installed in plant, and both produced RMSEP under reproducibility values of the reference methods. The models have been proved for on-line simultaneous determination of seven properties: density, cetane index, fatty acid methyl esters (FAME) content, cloud point, boiling point at 95% of recovery, flash point and sulphur. © 2017

Garcia Barneto A.,University of Huelva | Carmona J.A.,University of Huelva | Barron A.,CEPSA Inc
Energy and Fuels | Year: 2015

The thermal degradation profile for any type of oil-based sample under thermogravimetric analysis (TGA) conditions exhibits three distinct stages, namely, vaporization from room temperature to 340-350°C, cracking from 340-350°C to 480-500°C, and char oxidation from 500°C to 570°C. The former two stages occur in both inert (nitrogen) and oxidative (air) environments, whereas the latter only occurs in the presence of oxygen. Deconvoluting thermogravimetric data allows one to estimate the composition of oil derivatives with a view to expeditiously obtaining useful information from a refining process. To this end, thermal degradation of crude oil and its main refining cuts were modeled here by using the smallest possible number of representative pseudo-components. In order to ensure accurate fitting of thermogravimetric results, mass losses were interpreted in terms of autocatalytic kinetics. Fitting to an nth-order kinetics was useful below 350°C (vaporization), but not above this temperature, because of cracking with fast mass losses in the vicinity of certain temperatures. This modeling scheme for thermogravimetric results afforded the following conclusions: (i) atmospheric gas-oil typically contains 10% residual kerosene fraction; (ii) atmospheric residue still contains 35-45% distillable compounds; (iii) the main component of visbreaking feed (nearly 66%) degrades at a similar temperature as asphaltenes; (iv) visbreaking residue is similar to feed at high temperatures but contains light components similar to naphtha or gas-oil, which vaporize at low temperatures; and (v) simulating crude oil allowed us to estimate the potential production of distillates (62.93% from heavy crudes and 79.61% from light crudes). Such useful information can be used by process engineers to assess the performance of equipment such as distillation columns or visbreaking units, and also to estimate the quality of some streams, such as atmospheric gas-oil or visbreaking feed. © 2015 American Chemical Society.

Barneto A.G.,University of Huelva | Carmona J.A.,University of Huelva | Garrido M.J.F.,CEPSA Inc
Thermochimica Acta | Year: 2016

Monitoring asphaltenes is very important with a view to optimizing visbreaking units in oil refineries. Current analyses based on selective dissolution in different solvents are slow, so new, more expeditious methods for measuring asphaltenes are required to facilitate fuel-oil production. In this work, we studied the thermal degradation of asphaltenes as the potential basis for a thermogravimetric method for their monitoring in visbreaking streams. The thermal degradation of asphaltenes occurs largely from 400 to 500°C; the process is quite smooth in an inert environment but involves several fast mass loss events in the air. Kinetic parameters for characterizing the process were determined by using two model-free methods and the modified Prout-Tompkins kinetic equation to examine asphaltene thermolysis. Both types of methods showed the activation energy to increase during pyrolysis but to remain almost constant during cracking in the presence of oxygen or even diminish during char oxidation. Deconvoluting the thermogravimetric profiles revealed that asphaltene thermolysis in the air cannot be accurately described in terms of an nth order kinetic model because it involves some acceleratory phases. Also, thermogravimetric analyses of visbreaking streams revealed that char production in them is proportional to their asphaltene content. This relationship enables the thermogravimetric measurement of asphaltenes. © 2016 Elsevier B.V. All rights reserved.

Cantarero S.,University of Granada | Prieto C.A.,CEPSA Inc | Lopez I.,CEPSA Inc
Journal of Environmental Management | Year: 2012

Agricultural application has become the most widespread method of sewage sludge disposal, being the most economical outlet for sludge and also recycling beneficial plant nutrients and organic matter to soil for crop production. As a matter of fact, the European Sewage Sludge Directive 86/278/EEC seeks to encourage the disposal of sewage sludge in agriculture applications and regulate its use to prevent harmful effects on the soil environment. At the present time, the sewage sludge Directive is under revision and a possible cut-off limit for some organic chemicals may be implemented. Linear alkylbenzene sulphonate (LAS), the main synthetic anionic surfactant, has been included in the draft list of chemicals to be limited. The present research work deals with the monitoring of LAS and soap in Spanish sewage sludge. The average concentration of LAS found in anaerobic sewage sludge samples was 8.06g/kg, higher than the average values for European sludge. Besides, it has been also found that more than 55% of Spanish anaerobic sludge would not fulfil the limit proposed by the 3rd European Working paper on sludge. As a consequence, the implementation of the limit for LAS would make the disposal of most Spanish biosolids for agricultural applications almost impossible. Regarding the mechanisms why anionic surfactants are found in sludge, two surfactants are compared: LAS and soap, both readily biodegraded in aerobic conditions. Irrespective of the anaerobic biodegradability of soap, its concentration found in sludge is higher than LAS (only anaerobically biodegradable under particular conditions). The relevance of anaerobic biodegradation to assure environmental protection is discussed for this case. © 2011 Elsevier Ltd.

Gutierrez J.M.,University of Cádiz | Aguado Teixe J.M.,CEPSA Inc | Martin J.A.,University of Cádiz | Cubillas P.R.,University of Cádiz
Heat Transfer Engineering | Year: 2015

The sequential estimation of surface heat flux from discrete and noisy data of surface temperature is an ill-posed problem. From Duhamel's theorem and Fourier's law and using a stabilization technique based on the sequential application of the ordinary least squares (SOLS), we obtain a relatively simple but effective method. As the SOLS method uses a least squares fit over r-future and r-past temperatures, this method can be compared with the well-known function specification method (FSM). FSM is a more general method, but the numerical validations considered in this study reveal that the SOLS method gives better results. It is also shown that SOLS cannot be guided by the residual principle and consequently cannot be used in a practical scope. The ultimate goal of this study is to obtain a reliable estimation of heat flux history in an on-line industrial process where the tuneable parameter should be a time-variable r-value and it must be automatically updated from the experimental data. This requires that (i) the corresponding SOLS algorithm must be rewritten in recursive form, (ii) the classical definition of the residual principle is rewritten in recursive form, and (iii) the estimates are obtained from a hybrid procedure based on SOLS and FSM. 2016 Copyright © Taylor & Francis Group, LLC

Garcia-Carballido C.,Maersk Oil | Garcia-Carballido C.,CEPSA Inc | Boon J.,Royal Dutch Shell | Tso N.,Royal Dutch Shell
AAPG Memoir | Year: 2010

Numerous dipmeter and borehole image log data sets have been acquired over the years and are being used to build subsurface models. Dealing with dipmeter and image log data remains a niche skill within the petroleum industry, and because these are not conventional log data sets, they tend to be neglected in the way data are stored and quality controlled. A variety of wireline and logging-while-drilling tools exist, and each logging run contains a variety of curves with tool-specific mnemonics. For a particular data set, there may be several tens of curves from the raw data set and hundreds from the processed and interpreted data sets. Data quality control (QC) is an essential procedure that has to be conducted to assure dipmeter and image log data integrity in the subsurface models. Data QC should be performed iteratively during data acquisition, data management, processing, and interpretation. This chapter presents standard and globally applicable corporate guidelines for data management and data QC of dipmeter and image log data sets. Copyright © 2010 by The American Association of Petroleum Geologists.

Chalco A.,CEPSA Inc
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010

The interpretation of fluid inclusions mass spectrometry analysis from core plug samples of the Ungumayo-IX exploratory well and to core plug samples from a neighbouring oilfield in the Maranon Basin (Peru), suggest the potential presence of an hydrocarbon accumulation, either updip of the Ungumayo-IX well or at underlying Early Cretaceous undrilled reservoir, opening the opportunity to test a new play in the area. © 2010, European Association of Geoscientists and Engineers.

Mondragon J.C.,CEPSA Inc
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010

The prolific Magdalena basin is an elongated and narrow depression located between the Eastern and Central Colombian Mountain Ranges. This basin has been divided in three subbasins called Upper, Middle and Lower Magdalena basins. Recent studies carried out by Cepsa in the southern part of the Middle Magdalena Valley Basin (MMVB) strongly suggest that this area have undergone a very distinctive tectonostratigraphic evolution. The current tectonic configuration in the southern MMVB has been generated by the structural convergence between the Ibague transpressive fault system and the late Miocene-Pliocene inversion and uplifting of the Eastern Cordillera (Figure 1). The technical evaluation indicates that faults related to the Ibague transpressive system, related to the Caribeean plate motion to the NE, controlled the sedimentation during the late Cretaceous and Tertiary times. Afterwards, the Andean Orogeny exhumed the Cretaceous organic facies along Bituima and Alto del Trigo fault planes. On the other hand, the geochemical modeling suggests that significant hydrocarbon generation processes took place during late Eocene-late Oligocene times. In addition, upper Cretaceous organic facies are currently near the early stages of the oil window © 2010, European Association of Geoscientists and Engineers.

News Article | October 27, 2014

Salamander Energy Plc rose the most in six years in London trading after the U.K. oil explorer with a focus on Asia said it was in talks with two possible buyers. The company advanced 17 percent, the biggest jump since November 2008, to 93.50 pence by the close in the city. Salamander “has received a conditional proposal from Ophir Energy Plc with respect to a potential offer for the company,” it said today in a statement. The London-based company has also been approached by a group led by Cia Espanola de Petroleos, known as Cepsa, and Jynwel Capital Ltd., it said. Shareholders are advised not to act yet, Salamander said. The two companies have until Nov. 24 to make a firm offer. “We have previously written we believe the Salamander story will need to gain traction with the equity market or the company will likely be sold,” Thomas Martin, a Canaccord Genuity Group Inc. analyst, said in a note. “It appears the sale route is now a real possibility in the near term.” Ophir, an explorer focused on Africa, withdrew an approach for Premier Oil Plc in April. Today, it announced a deal to buy interests in deepwater Indonesia to expand in Southeast Asia. Cepsa, owned by Abu Dhabi sovereign wealth fund International Petroleum Investment Co., was considering a 700 million-euro ($888 million) bid for Salamander, the Expansion newspaper reported in May. Last year, it bought Coastal Energy Co., an explorer centering on Southeast Asia. The Ophir and Cepsa bids may value Salamander at 275 million pounds ($443 million), the Sunday Times said yesterday. That’s about a 32 percent premium to its value at the Oct. 24 close. Salamander began a “formal sales process” in May after a “small number of preliminary and conditional approaches,” the company said. It agreed in July to sell a stake in two oil and gas blocks in Thailand, subject to the discussions, it said.

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