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Piedecuesta, Colombia

Diaz-Mateus F.,Ambiocoop Ltda | Castro-Gualdron J.,Ecopetrol SA
CTyF - Ciencia, Tecnologia y Futuro | Year: 2010

A mathematical model for simulation of refinery furnaces is proposed. It consists of two different submodels, one for the process side and another for the flue gas side. The process side is appropriately modeled as a plug flow due to the high velocity of the fluid inside the tubes. The flue gas side is composed by a radiative chamber and a convective section both connected by a shield tube zone. Both models are connected by the tube surface temperature. As the flue gas side model uses this temperature as input data, the process side model recalculates this temperature. The procedure is executed until certain tolerance is achieved. This mathematical model has proved to be a useful tool for furnace analysis and simulation.

Diaz-Mateus F.-A.,Ambiocoop Ltda | Castro-Gualdron J.-A.,Ecopetrol SA
CTyF - Ciencia, Tecnologia y Futuro | Year: 2011

Tube skin peak temperature is one of the major parameters in furnaces operation since they determine the life of the tubes and the extent of an operation run. This parameter is very difficult to calculate appropriately in magnitude and location within the furnace, and commercial furnace simulators usually fail in its calculation. Computational fluid dynamics (CFD) is the only technique that calculates peak skin temperatures with great precision and accuracy since radiation and convective heat fluxes can be calculated taking into account every singularity of the geometry of the furnace and the burners. In this work, a technique is developed to calculate this parameter using CFD commercial code (Ansys Fluent) and an in-house furnace simulator (EcoFursim ©). When results of the simulations are compared to data from different furnaces from Barrancabermeja refinery (Barrancabermeja, Colombia), a good agreement is observed. Refinery furnace is referred in this paper to fired heaters for non reacting heat up of hydrocarbons or petroleum crude.

Poveda G.I.D.,Ecopetrol SA | Cajica N.E.M.,Ambiocoop Ltda | Morantes E.A.,Ecopetrol SA | Ballesteros D.Y.P.,Industrial University of Santander
NACE - International Corrosion Conference Series | Year: 2013

Materials selection has become one of the most important factors in the design and repair of refinery processing equipment. Processing crude oil with high naphthenic acid (TAN) and high sulfur content can lead to high corrosion rates in stainless steels at temperature approximately of 350 °C. This paper presents the results of laboratory and field tests conducted to assess the corrosion resistance of different materials used in refinery construction, especially stainless steels type 316L (UNS S31603), type 317L (UNS S31703) and a new generation of 400 series stainless type 444 (UNS S44400). The laboratory tests were carried in a dynamic autoclave using a rotation speed of 600 rpm. Field test consisted of exposing corrosion coupons in the transfer line between furnace and atmospheric tower. Results have shown that stainless type 444 is an alternative material at processing crudes with high sulfur and naphthenic acid content. © 2013 by NACE International.

Castro-Gualdron J.-A.,Ecopetrol SA | Abreu-Mora L.-A.,Ecopetrol SA | Diaz-Mateus F.-A.,Ambiocoop Ltda
CTyF - Ciencia, Tecnologia y Futuro | Year: 2013

The homogenization of different crude oils in a pilot plant tank is simulated using Computational Fluid Dynamics (CFD) commercial code. The models are inherently transient since all simulations start from a time zero where the crudes are completely separated to a final time of full homogenization. The tank is agitated with a small impeller and a two-phase model is used in the simulations in order to see the mixing process and calculate the properties of the blend based on the volume fractions. The effect of the mesh size and time step size are studied since in this type of simulations the computational effort becomes a major parameter and has to be reduced to a minimum. Experimental data taken from two different points in the tank at regular time intervals are available to compare the results of the simulations, concluding in good agreement.

Lopez D.C.,Ecopetrol SA | Hoyos L.J.,Ecopetrol SA | Chaparro S.M.,Ambiocoop Ltda | Castro J.A.,Ecopetrol SA
11AIChE - 2011 AIChE Spring Meeting and 7th Global Congress on Process Safety, Conference Proceedings | Year: 2011

The optimization of a complex system of crude oil distillation units (CDU) belonging to a Colombian refinery of ECOPETROL SA is presented. The system is composed by crude oil blending scheme and all distillation units installed in the refinery. The distillation units include 5 atmospheric towers, 5 atmospheric furnaces, and 4 vacuum towers. Crude oil blending is integrated for 14 Colombian crude oils. Optimization results were optimum feedstock composition and operating conditions for the CDU system, which were carried out using a non linear programming (NLP) model. In the NLP model, crude oil blending restrictions were mass balances, mixing rules, property boundaries like acidity, sulfur content, specific gravity. It evaluated new crude oil blending schemes, e.g., segregation of crude oil streams in the current pre-mixtures and inclusion of new pre-mixtures for the refinery. The model calculated the best performance of distillation system for the new cases. This is an abstract of a paper presented at the 2011 AIChE Spring Meeting & 7th Global Congress on Process Safety (Chicago, IL 3/13-17/2011).

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