225 results found
Diaz-Bejarano E, Coletti F, Macchietto S, 2017, Thermo-hydraulic analysis of refinery heat exchangers undergoing fouling, AIChE Journal, Vol: 63, Pages: 984-1001, ISSN: 0001-1541
A complete, systematic approach is presented for the analysis and characterization of fouling and cleaning in refinery heat exchangers. Bringing together advanced thermo-hydraulic dynamic models, some new formulations, and a method for dynamic analysis of plant data, it allows: extracting significant information from the data; evaluating the fouling state of the units based on thermal measurements and pressure drops, if available; identifying the range of deposit conductivity leading to realistic pressure drops, if pressure measurements are unavailable; estimating key fouling and ageing parameters; estimating the effectiveness of cleaning and surface conditions after a clean; and predicting thermal and hydraulic performance with good accuracy for other periods/exchangers operating in similar conditions. An industrial case study demonstrates the performance prediction in seamless simulations that include partial and total cleanings for over 1000 days operation. The risks of using thermal effects alone and the significant advantages of including pressure drop measurements are highlighted.
Macchietto S, Coletti F, 2017, Engineering innovation by design: The uniheat project, Pages: 238-257
Diaz-Bejarano E, Coletti F, Macchietto S, 2017, A novel way of monitoring heat exchanger performance: The dynamic TH-γ plot, Pages: 274-285
In many industrial situations, from milk processing to refining, heat exchanger performance changes over time due to deposition of material on exchange surfaces (fouling) leading to losses in duty (reduced thermal efficiency) and increased pressure drop (reduced hydraulic efficiency). Operating performance is usually measured by monitoring just thermal efficiency, typically using thermal efficiency measures such as fouling resistance, Rf, that are easy to calculate. The reasons of thermal inefficiency, however, can be quite varied, ranging from different deposition rates, deposition of materials with different thermal conductivity, coking of existing deposits, to removal of deposits by shear, often having opposite effects. On its own, simply monitoring fouling resistance can give quite misleading indications of performance, and of the underlying conditions of the exchanger. The dynamic TH-γ plot is an easy to understand, rich visualisation that combines information about both the thermal and hydraulic evolution of the performance of a heat exchanger. In its simplest form, it evidences the changes in duty and pressure drop relative to clean performance and permits tracking and assessing the approach to thermal (T) and hydraulic (H) limits. The addition of characteristic reference lines for deposits of constant thermal conductivity, the so called γ -lines, allows monitoring and in many cases helps identify the degree of deposit coking, abnormal events such as acute fouling and inorganics breakthrough. When process conditions (flowrates and temperatures of the streams) are variable, as is common in practice, the reference performance (clean and l-lines) are obtained using a sophisticated dynamic model of the exchanger under fouling. Using a variety of industrial examples, the presentation will illustrate the ability of such a representation and underlying models to resolve the ambiguities of simpler thermal resistance metrics, provide an improved understand
Seegulam N, Coletti F, Macchictto S, 2017, Effect of Fouling on Control and Energy Recovery in an Industrial CDU Column, Editors: Espuna, Graells, Puigjaner, Publisher: ELSEVIER SCIENCE BV, Pages: 1555-1560
Diaz-Bejarano E, Porsin AV, Macchietto S, 2017, Fossil fuel: Energy efficient thermal retrofit options for crude oil transport in pipelines, The Water-Food-Energy Nexus: Processes, Technologies, and Challenges, Pages: 277-296, ISBN: 9781498760836
© 2018 by Taylor & Francis Group, LLC. Pipelines are used to transport large amounts of crude oil over large distances (either overland or subsea), representing the most economical alternative. Flow assurance faces two main problems: viscosity increase due to gradual cooling of the oil along the pipeline and fouling deposition. These problems are especially important in very cold environments (Russia, Alaska, North Sea, deep oceanic waters, etc.) and when dealing with nonconventional oils, usually heavy or extra-heavy oil and waxy oils. In many cases, the depletion of deposits in conventional oil reservoirs is gradually leading to more extraction of these types of feedstock from remote locations. All these situations result in pipeline transport difficulties such as increased pumping costs, reduced flow rates, and the possibility of flow inhibition or blockage, with potentially major economic impact (Correra et al., 2007; Martínez-Palou et al., 2011).
Coletti F, Diaz-Bejarano E, Macchietto S, 2017, Heat exchanger design with high shear stress: Evaluating the impact of Performance of Crude Pre-heat Trains, Pages: 167-178
Coletti F, Diaz-Bejarano E, Macchietto S, et al., 2017, Evaluation, prediction, management and mitigation of fouling in heat exchanger networks for improved energy efficiency, Pages: 3-18
Diaz-Bejarano E, Coletti F, Macchietto S, 2017, Monitoring and analysis of inorganics breakthrough in refinery pre-heat trains, Pages: 335-346
Monitoring of crude oil fouling in refinery heat exchanger typically focus on the gradual decay of thermal performance based on measured temperatures, heat duties or, most commonly, fouling thermal resistances. Such indicators, however, are inherently unable to provide information on the extent, location and composition of the fouling deposits, and therefore to successfully diagnose the underlying causes. The development of monitoring and analysis methods capable of discriminating such effects is particularly important when fouling is due breakthrough of inorganic foulants into the hot end of the preheat train, where organic deposition is usually assumed to be the dominant mechanism. Such problem may be a result of desalter malfunctioning, changes in feedstock or unsuitable management of operations. Here, a novel model-based monitoring and analysis approach is presented. It enables to improve the understanding on how complex deposit structures involving both inorganic and organic species affect the thermo-hydraulic performance of heat exchangers. From an operational stand point it allows the use of primary plant measurements to early detect, and diagnose the underlying causes. Slide 13 and following show and industrial case study in which pressure drop measurements have been used to fit the necessary model parameters (slide 14) and to assess the composition of the fouling layer using thermal (slide 15) and hydraulic (slide 16) predictions. The following slides show how this technique can be used for detection of inorganic breakthrough (slides 17,18, 19) and how this can be used for effective fouling monitoring and diagnosis (slides 20, 21).
Vianello C, Mocellin P, Macchietto S, et al., 2016, Risk assessment in a hypothetical network pipeline in UK transporting carbon dioxide, Journal of Loss Prevention in the Process Industries, Vol: 44, Pages: 515-527, ISSN: 0950-4230
With the advent of Carbon Capture and Storage technology (CCS) the scale and extent of its handling is set to increase. Carbon dioxide (CO2) capture plants are expected to be situated near to power plants and other large industrial sources. Afterward CO2 is to be transported to storage site using one or a combination of transport media: truck, train, ship or pipeline. Transport by pipeline is considered the preferred option for large quantities of CO2 over long distances. The hazard connected with this kind of transportation can be considered an emerging risk and is the subject of this paper.The paper describes the Quantitative Risk Assessment of a hypothetical network pipeline located in UK, in particular the study of consequences due to a CO2 release from pipeline.The risk analysis highlighted that some sections of pipeline network cross densely populated areas. For this reason, some changes in the original path of the network have been proposed in order to achieve a significant reduction in the societal risk.
Diaz-Bejarano E, Coletti F, Macchietto S, 2016, Impact of complex layering structures of organic and inorganic foulants on the thermohydraulic performance of a single heat exchanger tube: a simulation study, Industrial and Engineering Chemistry Research, Vol: 55, Pages: 10718-10734, ISSN: 0888-5885
Crude oil fouling in preheat trains in refineries is usually dominated by organic matter deposition at high temperatures. However, malfunction of desalting equipment, human or technical errors, or changes in feedstock may lead to substantial deposition of inorganic salts or corrosion products, compromising heat exchange performance, pressure drop (hence throughput), and even safety. Understanding how such abnormal deposition and the resulting complex deposit structure affect the thermohydraulic performance of heat exchangers is key to developing adequate monitoring tools for the early detection, diagnosis, and control of the underlying causes. Here, a novel multicomponent fouling deposit formulation is applied to the simulation of deposits composed of organic and inorganic foulants within a single heat exchanger tube. The model enables the tracking of changes and history of local composition in the fouling deposit, thermoconductivity profiles including layering effects, and impact on the overall thermohydraulic performance. The results show that appropriate monitoring of measurable stream conditions, including thermal and hydraulic effects, in combination with reliable predictive fouling and heat exchanger models, allows the detection and (potentially) diagnosing of the abnormal fouling behavior. The model is easily incorporated in full-scale heat exchanger models and is applicable to other processes.
Diaz-Bejarano E, Porsin AV, Macchietto S, 2016, Enhancing the flexibility of pipeline infrastructure to cope with heavy oils: Incremental thermal retrofit, Applied Thermal Engineering, Vol: 105, Pages: 170-179, ISSN: 1359-4311
Pipelines that were well designed for conventional oils may not be able to cope with a transition to heavy oils without some retrofit adaptation, as the increased pressure drop may exceed constraints and force some reduction in throughput. In this paper, ways of enhancing the utilization of existing, capital intensive infrastructure by small, incremental additions are explored. A thermo-hydraulic pipeline model for a buried pipeline is presented. The model is then applied to a case study involving a section of the important, recently built Russia-China ESPO pipeline, for which a gradual shift from the current (design) light oil to heavier oils is considered. A number of thermal retrofit scenarios are proposed and assessed which involve the incremental supply of additional heat at selected points. These scenarios go from pre-heating of the oil at entrance to use of single and multiple intermediate heating stations. The heating duty requirements for each case are calculated. The results show that a careful use of such thermal management techniques can significantly mitigate the reduction in throughput that would otherwise be required, leading to significant economic savings in operations. It is highlighted that the development of adaptable, modular low-cost heating technologies would make this approach significantly advantageous over other alternatives.
Diaz-Bejarano E, Coletti F, Macchietto S, 2016, Crude oil fouling deposition, suppression, removal, and consolidation and how to tell the difference, Heat Transfer Engineering, Vol: 38, Pages: 681-693, ISSN: 0145-7632
Crude oil fouling on heat transfer surfaces is often described as the result of two competing mechanisms: a deposition and a deposition-offsetting mechanism. There is uncertainty about whether the offsetting mechanism is suppression (due inhibition of attachment or back-diffusion of foulant from near the wall into the bulk) or removal of foulant already deposited, due to (i) difficulties in experimentally identifying and isolating the key phenomena and (ii) the cumulative measurement of deposition rates by monitoring thermal exchange rates (or resistance) alone. Here, the question is addressed of whether it is conceptually possible to distinguish such phenomena, and if so, in which conditions. A recently developed two-dimensional (2D) deposit model and a thermohydraulic model of a heat exchanger tube are used to assess the system response to removal, suppression, aging, and consolidation (for which a new model is proposed). It is shown that while suppression or removal lead to undistinguishable behavior during overall deposit growth, thermal and hydraulic responses will differ in certain conditions, for which an experimental procedure is suggested. Simultaneous consideration of thermal and hydraulic effects and accurate characterization of the deposit aging and consolidation processes are suggested as a way to allow the unambiguous identification of the dominant deposition-offsetting mechanism.
Ho WS, Macchietto S, Lim JS, et al., 2016, Optimal scheduling of energy storage for renewable energy distributed energy generation system, Renewable & Sustainable Energy Reviews, Vol: 58, Pages: 1100-1107, ISSN: 1364-0321
Energy storage (ES) is an important device to ensure operation stability and efficiency of a renewable energy based distributed energy generation (DEG) system. As such, many researchers have modelled the operation (scheduling) of energy storage in a DEG system, where it is mostly portrayed to operate on a daily cycle. In this paper, an analysis of the operation mode of energy storage is presented. Two modes of operation are defined, daily mode (DM) (ES operates in daily cycles) and weekly mode (WM) (ES operates in weekly cycles) which are modelled accordingly. This paper then attempts to analyse and compare between both modes in term of operation and cost. The analysis is performed through a mixed integer linear programming (MILP) model programmed via the General Algebraic Modelling System (GAMS). In general, with high capital cost of ES, it is advisable to program the ES to operate in a DM. The reason to this conclusion is mainly due to three factors, intermittency of renewable resources, varying weather conditions, and discharge rate of ES(s).
Diaz-Bejarano E, Coletti F, Macchietto S, 2016, Model-based monitoring of thermal-hydraulic performance of refinery heat exchangers undergoing fouling, Editors: Kravanja, Bogataj, Publisher: ELSEVIER SCIENCE BV, Pages: 1911-1916
Lanchas-Fuentes L, Diaz-Bejarano E, Coletti F, et al., 2016, Condition-based chemical cleaning of crude oil deposits - a conceptual model, Editors: Kravanja, Bogataj, Publisher: ELSEVIER SCIENCE BV, Pages: 1905-1910
Diaz-Bejarano E, Coletti F, Macchietto S, 2015, A New Dynamic Model of Crude Oil Fouling Deposits and Its Application to the Simulation of Fouling-Cleaning Cycles, AICHE Journal, Vol: 62, Pages: 90-107, ISSN: 0001-1541
Modelling of crude oil fouling in heat exchangers has been traditionally limited to a description of the deposit as a thermal resistance. However, consideration of the local change in thickness and the evolution of the properties of the deposit due to ageing or changes in foulant composition is important to capture the thermal and hydraulic impact of fouling. A dynamic, distributed, first-principles model of the deposit is presented that considers it as a multicomponent varying-thickness solid undergoing multiple reactions. For the first time, full cleaning, partial cleaning, and fouling resumption after cleaning can be simulated in any order with a single deposit model. The new model, implemented within a single tube framework, is demonstrated in a case study where various cleaning actions are applied following a period of organic deposition. It is shown that complete mechanical cleaning and chemical cleaning of different extent, according to a condition-based efficacy, can be seamlessly simulated.
Tajudin Z, Martinez-Minuesa JA, Diaz-Bejarano E, et al., 2015, Experiment Analysis and Baseline Hydraulic Characterisation of HiPOR, a High Pressure Crude Oil Fouling Rig, ICHEAP12: 12TH INTERNATIONAL CONFERENCE ON CHEMICAL & PROCESS ENGINEERING, Vol: 43, Pages: 1405-1410, ISSN: 1974-9791
Macchietto S, Coletti F, 2015, Innovation: Better together, TCE The Chemical Engineer, Pages: 24-27, ISSN: 0302-0797
Diaz-Bejarano E, Pelloja G, Coletti F, et al., 2015, Heat Exchanger Bypass Control to Mitigate the Cost of Fouling in Refinery Preheat Trains, ICHEAP12: 12TH INTERNATIONAL CONFERENCE ON CHEMICAL & PROCESS ENGINEERING, Vol: 43, Pages: 2119-2124, ISSN: 1974-9791
Yang J, Tajudin ZB, Coletti F, et al., 2015, Numerical simulation of fouling in crude-oil heat exchangers: The interaction between different fouling routes, Pages: 833-842
Coletti F, Crittenden BD, Haslam AJ, et al., 2015, Modeling of Fouling from Molecular to Plant Scale, Crude Oil Fouling: Deposit Characterization, Measurements, and Modeling, Pages: 179-320, ISBN: 9780128012567
© 2015 Elsevier Inc. All rights reserved. Chapter 5 describes a multiscale approach to modeling of crude oil fouling focused on improving understanding from the molecular level to industrial-scale systems. At the molecular scale, modeling work allows the determination of key parameters, such as diffusion coefficients and fluid physical properties, which can be used in thermodynamic equations of state and detailed fluid-dynamic models to predict fouling deposition in simple flows. At large scale, advanced system models of refinery heat exchangers and heat exchanger networks incorporate the lessons learned from the smaller scale models and provide the ability to predict the future course of fouling. It is shown how these models can be used for accurately assessing operational costs due to fouling, assisting in heat exchanger design, and devising improved operating strategies that minimize costs.
Diaz-Bejarano E, Coletti F, Macchietto S, 2015, Detection of changes in fouling behavior by simultaneous monitoring of thermal and hydraulic performance of refinery heat exchangers, 12TH INTERNATIONAL SYMPOSIUM ON PROCESS SYSTEMS ENGINEERING (PSE) AND 25TH EUROPEAN SYMPOSIUM ON COMPUTER AIDED PROCESS ENGINEERING (ESCAPE), PT B, Vol: 37, Pages: 1649-1654, ISSN: 1570-7946
Coletti F, Crittenden BD, Macchietto S, 2015, Basic Science of the Fouling Process, Crude Oil Fouling: Deposit Characterization, Measurements, and Modeling, Pages: 23-50, ISBN: 9780128012567
© 2015 Elsevier Inc. All rights reserved. Chapter 2 reviews the science of the fouling process. The basic fouling mechanisms-crystallization, particulate, chemical reaction, corrosion, and biological fouling-are described with particular focus on the mechanisms underlying crude oil fouling: chemical reaction and corrosion fouling. Possible routes of formation of crude oil fouling deposits are then discussed. These include autoxidation, corrosion, polymerization, thermal cracking, and asphaltene precipitation. Several events occurring in fouling-initiation, transport, attachment, removal, and ageing-are also discussed. Finally, the chapter reviews the effects that key variables such as crude oil composition, operating conditions, and surface conditions have on these events.
Tajudin ZB, Diaz-Bejarano E, Coletti F, et al., 2015, 435539 Effect of friction factor correlations and propagation errors on differential pressure in a crude OIL fouling measuring RIG, Pages: 446-447
In order to detect crude oil fouling experimentally, primary measurements of differential pressure and temperatures must be obtained with high fidelity, accuracy and reproducibility at (or close to) industrial conditions. Information of the thermal and hydraulic effects of fouling can be studied by using robust models to decouple the various phenomena involved. To start with, it is important to have a reliable set of primary measurements in which the robust model could be validated against the experiment data.
Schuller B, 2015, Foreword, Publisher: Springer
Hashim H, Ho WS, Lim JS, et al., 2014, Integrated biomass and solar town: Incorporation of load shifting and energy storage, ENERGY, Vol: 75, Pages: 31-39, ISSN: 0360-5442
Galvanin F, Barolo M, Macchietto S, et al., 2014, Identification of Physiological Models of Type 1 Diabetes Mellitus by Model-Based Design of Experiments, Process Systems Engineering, Pages: 545-581, ISBN: 9783527316847
Ho WS, Khor CS, Hashim H, et al., 2014, SAHPPA: a novel power pinch analysis approach for the design of off-grid hybrid energy systems, CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY, Vol: 16, Pages: 957-970, ISSN: 1618-954X
Vianello C, Macchietto S, Maschio G, 2013, Risk Assessment of CO2 Pipeline Network for CCS - A UK Case Study, LP2013 - 14TH SYMPOSIUM ON LOSS PREVENTION AND SAFETY PROMOTION IN THE PROCESS INDUSTRIES, VOLS I AND II, Vol: 31, Pages: 13-18, ISSN: 2283-9216
Hashim H, Ho WS, Lim JS, et al., 2013, Integrated Biomass and Solar Town Concept for Smart Eco-Village, 16th International Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES), Publisher: AIDIC SERVIZI SRL, Pages: 577-582, ISSN: 2283-9216
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