Richard Szczepanski - Academia.edu (original) (raw)

Papers by Richard Szczepanski

Geoenergy Science and Engineering, Nov 30, 2023

Chemical Engineering Science, 1987

This volume follows the format and approach of the first edition, Fluidization, edited by J. Davi... more This volume follows the format and approach of the first edition, Fluidization, edited by J. Davidson and D. Harrison, 197 1 by providing a compilation of expository chapters written by internationally recognized experts, covering various aspects of fluidization. The chapter titles and authors are: 1. Incipient Fluidization and Particulate Systems (J.P. Couderc); 2. Hydrodynamic Stability of Fluid-Particle Systems (R. Jackson); 3. Continuous Bubbling and Slugging (R. Clift, J.R. Grace); 4. Gas Jets in Fluidized Beds (L. Massimilla); 5. Distributor Characteristics and Bed Properties (A.B. Whitehead); 6. Spouted Beds (J. Bridgwater);

Fluid Phase Equilibria, Mar 1, 1996

In the course of work to develop a new and consistent model of hydrates and hydrate inhibitors we... more In the course of work to develop a new and consistent model of hydrates and hydrate inhibitors we have made some unexpected predictions about the structure of hydrates that appear to be supported by the currently available experimental data. Based on the data and on the accepted theory of thermodynamic stability, we conjecture, that the hydrate formed by certain mixtures

Oil & Gas Journal - OIL GAS J, 1996

Modeling condensate and gas kicks in a deep North Sea well helps drillers understand what to expe... more Modeling condensate and gas kicks in a deep North Sea well helps drillers understand what to expect after prompt kick detection in a straight-forward kick circulation program with competent choke handling. Concerns have been raised in the industry that as a condensate kick is taken and subsequently circulated out of the well, unexpected surface indications may be present. Blowouts, resulting from uncontrolled kicks, could be particularly hazardous for condensate fields as these are often high-pressure, high-temperature operations. A deeper understanding of the differences, and similarities, between gas and condensate kicks has resulted from an investigation by Infochem Computer Services Ltd., funded by the UK Health and Safety Executive (HSE). This study has led to an assessment of the practical significance of any differences for the personnel involved in well control.

Oil & Gas Journal - OIL GAS J, 1998

Hydrate formation is a growing safety concern for offshore drilling programs, but, despite extens... more Hydrate formation is a growing safety concern for offshore drilling programs, but, despite extensive laboratory research, pragmatic information is still lacking. Formation of hydrates in drilling fluids during a shut-in is the most likely hydrate-associated hazard in deep-water drilling, although the number of documented incidents is small. In addition to the known naturally forming hydrates, laboratory experiments have also identified heavier hydrocarbons found in oil and gas condensate systems and a new hydrate structure. These two factors may increase the range from which hydrate formation can occur. The paper discusses safety concerns, hydrate structures, modeling hydrates, hydrate stability, naturally occurring hydrates, techniques for drilling hydrates, hydrate formation while drilling, drilling fluids and hydrates, and completion fluids.

Social Science Research Network, 2023

Fluid Phase Equilibria, 1983

... Netherlands CALCULATION 0F PHASE EQUILIBRIA BY MINIMIZATION TECHNIQUES PROBLEMS 0F THERMO-DYN... more ... Netherlands CALCULATION 0F PHASE EQUILIBRIA BY MINIMIZATION TECHNIQUES PROBLEMS 0F THERMO-DYNAMIC CONSISTENCY GRAHAM SAVILLE and ... Projection Method We have adapted the Variable Metric Projection (VMP) method of Sargent and Murtagh ...

Fluid Phase Equilibria, Nov 1, 2020

A good understanding of the solubility of elemental mercury over wide ranges of temperature, pres... more A good understanding of the solubility of elemental mercury over wide ranges of temperature, pressure and composition is an important issue to assess the possibility of mercury dropping out in gas processing streams. In this work, new mercury solubility in three multicomponent systems with methane content varying between 89-26 mol% have been measured over a wide range of temperature (243.15 to 323.15 K) and pressure and up to 20 MPa. A group contribution method for the Peng-Robinson equation of state has been used to allow calculation of binary interactions between mercury and saturated hydrocarbons, aromatic hydrocarbons, nitrogen and carbon dioxide. The parameters of the group contribution have been adjusted using mercury solubility previously measured in single components. Predictions of the developed model are validated against independent experimental data and the data generated in this work. A good agreement between predictions and experimental data is observed, supporting the reliability of the developed model.

Fluid Phase Equilibria, Oct 1, 2020

Mercury in its elemental form is naturally present in most reservoir fluids. The presence of merc... more Mercury in its elemental form is naturally present in most reservoir fluids. The presence of mercury can lead to serious operational and safety/health problems. Knowledge of the maximum solubility of elemental mercury with temperature and pressure in reservoir fluids is important to avoid mercury dropping out during processing operations, as mercury is naturally present in hydrocarbon deposits. In this work, a new experimental approach is presented to determine the mercury content in high pressure gas and liquid systems. Mercury solubility in methane, ethane, propane, nitrogen and carbon dioxide over a wide range of temperature and pressure (243.15 to 323.15K and up to 20 MPa) have been measured. An extensive literature review has been conducted on the solubilities of mercury in gases and liquid hydrocarbons. A critical evaluation of the literature data has been conducted to identify any inconsistencies in the reported data. The new experimental data generated in this work along with the literature data have been used to tune the binary interaction parameters of the Peng-Robinson and the Soave-Redlich-Kwong equations of state between mercury and the mentioned compounds.

Chemical Engineering Science, 1982

... METHANEBASED EQUATIONS OF STATE FOR A CORRESPONDING STATES REFERENCE SUBSTANCE GRAHAM SAVILLF... more ... METHANEBASED EQUATIONS OF STATE FOR A CORRESPONDING STATES REFERENCE SUBSTANCE GRAHAM SAVILLF and RICHARD SZCZEPANSKI Department of ... A similar scheme was applied to hydrogen using the equation of state developed by McCarty [8] but ...

Fluid Phase Equilibria, Oct 1, 1986

... DISCUSSION Isothermal Flash Feed compositions and conditions for two flash examples, A and B ... more ... DISCUSSION Isothermal Flash Feed compositions and conditions for two flash examples, A and B (Michelsen, 1980) are given in Table 1. Base point solutions were obtained with values of ks in Table 2 and critical constants from Reid et al, 1977. ...

Energy & Fuels, Mar 10, 2006

A number of wax models currently in use by the oil industry are based on parameters that were emp... more A number of wax models currently in use by the oil industry are based on parameters that were empirically determined to match available data for black oils. These data are often not very precise. The recently developed predictive local composition model is, however, a predictive, theoretically well-defined model based on highaccuracy thermodynamic data. The paper describes how the predictive local composition model can be used in conjunction with conventional cubic equations of state to perform wax equilibrium calculations for black oils. Examples are given that show how the model can predict both wax appearance temperature and the amount of wax precipitated at varying temperatures with or without detailed n-paraffin analyses. The examples presented include the effect of pressure on live oils. The improved thermodynamic modeling of wax formation will allow for better prediction of wax deposition rates for flow assurance.

Fluid Phase Equilibria, Jun 1, 1999

A consistent approach to calculating the phase equilibria of solids, liquids and gases is present... more A consistent approach to calculating the phase equilibria of solids, liquids and gases is presented. Examples of complex phase behaviour involving solid depositions from petroleum fluids are shown which have been calculated in this way. Important practical examples include cases where different solid phases are present and affect one another.

Energy & Fuels, Nov 8, 2007

A method is presented for simulating wax deposition in pipelines in which the wax phase is repres... more A method is presented for simulating wax deposition in pipelines in which the wax phase is represented as a continuous distribution of n-paraffin components. The thermodynamic properties of the wax are predicted using a previously developed thermodynamic model. We have adopted a mass transfer model to predict the likely rate of wax deposition. Predictions from the model are compared with observations of flow-loop experiments, and predictions for full-scale pipelines are presented. The impact of the removal of deposited wax by shearing is also investigated. We demonstrate the effect of assuming molecular diffusion to be the dominant mechanism of wax deposition, and we also show that not representing the wax with its full n-paraffin distribution leads to serious distortions of the pipeline simulations. Practical software development issues in the implementation of the model are outlined. † Presented at the 8th International Conference on Petroleum Phase Behavior and Fouling.

Journal of the Chemical Society, 1987

Non-equilibrium molecular dynamics, NEMD, computer simulation is used to characterise and underst... more Non-equilibrium molecular dynamics, NEMD, computer simulation is used to characterise and understand the nature of shear thinning in the gas phase. An extensive series of calculations is used to provide simple expressions which represent the effect of shear rate on the shear viscosity, the cartesian components of the self-diffusion coefficient and normal pressure differences for the dilute Lennard-Jones (LJ) fluid. The temperature range considered was T*= 1.5–10 and the density range was mainly less than ρ*= 0.1. Shear thinning in the gaseous phase is associated with a distortion of the Maxwell–Boltzmann velocity distribution. A shear-induced clustering of molecules is also observed at ρ= 0.01.

Advances in chemistry series, Jun 1, 1983

Aiche Journal, Jun 1, 1988

Modern equation-oriented simulators solve systems of equations and procedures using Newton's meth... more Modern equation-oriented simulators solve systems of equations and procedures using Newton's method or its variants. Partial derivatives of the output variables of procedures with respect to their input variables are required and are usually approximated by perturbation or quasi-Newton methods. Here it is shown how this partial derivative information can be computed exactly for procedures in general, with particular applications to flash and multicomponent distillation procedures. Results indicate that 1. physical property procedures should provide analytical derivatives of properties in addition to point values; 2. commonly used procedures for vapor-liquid equilibria calculation can easily be modified, and should be, to also return output/input gradients; and 3. the use of exact derivatives at all levels results in significant improvements in efficiency over present methods.

Computers & Chemical Engineering, Jul 1, 2011

A single-phase equilibrium reactor model has been developed, that calculates the reaction equilib... more A single-phase equilibrium reactor model has been developed, that calculates the reaction equilibrium at a fixed pressure by minimization of the Gibbs free energy at constant temperature, or a maximization of entropy at constant enthalpy. An automatic procedure of determining the reactions and stoichiometry is applied. The reactor model has been implemented in compliance with the CAPE-OPEN standards, and can therefore run in multiple simulation environments using different thermodynamic engines. Care must be taken by the unit operation not to evaluate thermodynamic properties at conditions for which the thermodynamic server may not provide answers. Specifically, it is important to evaluate thermodynamic properties only at mole fractions in the [0,1] region. A projection algorithm has been applied to ensure this. The reactor model has been tested in different simulation environments and is available in the free-of-charge COCO simulator suite.