XII-EROSION-CORROSION MODELING AND EXPERIMENTS. Introduction

Transcription

1 EROSION-CORROSION MODELING AND EXPERIMENTS XII-1 XII-EROSION-CORROSION MODELING AND EXPERIMENTS Introduction In the oil and gas production industry, when sand is produced, carbon steel tubing and piping are susceptible to erosion-corrosion due to the erosive and corrosive nature of the flow. The combined effect of erosion and corrosion can be very significant and can lead to catastrophic losses. Due to cost and/or production limitations, it is more feasible to control erosion-corrosion rather than prevent it. This has raised a need for developing a prediction model that can be used as a tool for controlling erosion-corrosion. A considerable amount of work can be found in the literature for modeling erosion and corrosion processes separately [1-6], but very limited work is available for modeling the integrated process of erosioncorrosion [7-9]. The objective of the current work was to develop a mechanistic model for predicting erosion-corrosion metal loss for selected multiphase flow regimes and flow geometries. Two different erosion-corrosion mechanisms were considered in this research. In the first mechanism, erosion-corrosion takes place in non scale-forming (FeCO 3 ) conditions. In the second mechanism, erosion-corrosion takes place in scale-forming conditions. In the second mechanism, protective corrosion product scale is prevented from forming, or is totally or partially removed by sand erosion. This research addresses important questions such as, what will happen to the protective scale if sand production starts? How can producers predict erosion-corrosion? What measures can producers take to control erosion-corrosion? The work presented in this paper is part of ongoing research at the Erosion/Corrosion Research Center (E/CRC) at the University of Tulsa. The E/CRC developed two programs for modeling CO 2 corrosion and sand particle erosion. The CO 2 corrosion prediction model, SPPS: CO 2, is a multiphase mechanistic model that has been updated and expanded since its introduction by Dayalan et al. [10]. The sand particle erosion model, SPPS, is one of the most comprehensive mechanistic models available for prediction of erosion [2]. The model computes erosion rate as a function of particle shape, impingement velocity, impingement angle and the hardness of the target material. These two models provide the foundation for the erosion-corrosion model developed in this work. The main contribution of the research presented here is modeling the competition between precipitation and growth of the scale and erosion of the scale. Solid particle erosion resistance of FeCO 3 scales was characterized by direct impingement experiments

2 XII-2 EROSION/CORROSION RESEARCH CENTER Experimental Work The objectives of the experimental work are to 1) generate iron carbonate scales, 2) characterize the scales as to thickness, morphology, and erosion resistance, and 3) generate erosion-corrosion data in a laboratory flow system. The experimental facility and the experimental procedure for each objective are described below. Iron Carbonate Scale Formation A single-phase flow loop has been used to produce iron carbonate, FeCO 3, scales at different environmental conditions. A schematic diagram of the loop is shown in Figure XII- 1. Two different test section geometries were used. The first geometry allows channel flow with two specimens flush mounted to the bottom wall (Figure XII-2-a). The second geometry allows jet flow with one specimen (Figure XII-2-b). The test specimens were designed to allow linear polarization resistance measurement (LPR), Figure XII-2-c. The reference element of the LPR specimen is made of 316 stainless steel and the working element is made of CS1018 (UNS: G10180). The composition of CS1018 is given in Table XII-1. Reference and working elements are electrically isolated with a ceramic insulator. Table XII-1.Weight Percent of CS1018 (UNS: G10180) C Mn P S Fe balance CO 2 Tank Test Section Pump Figure XII-1: Single-Phase Flow Loop for Scale Formation

3 EROSION-CORROSION MODELING AND EXPERIMENTS XII-3 Figure XII-2: Test Sections and LPR Specimen The tests were prepared in three steps: solution preparation, system deoxygenating, and CO 2 saturation. The solution was prepared outside the system by mixing the required mass of NaCl, and NaHCO 3 for ph control with distilled water. Once the solution is pulled into the tank, it was deoxygenated by running the system under vacuum for two hours. After completing de-aeration, the system was pressurized with 20 psig CO 2, heated to a target temperature, and kept under circulation overnight. At this point, the test section was bypassed and open to atmosphere to allow specimen installation. After overnight circulation, the specimens were installed; the test section was de-aerated and then opened to the flow. Iron Carbonate Scale Characterization Iron carbonate scales were characterized with respect to scale thickness and erosion resistance. Scanning electron microscopy (SEM) was used to provide scale thickness measurements. For characterizing erosion resistance of the scales, direct impingement tests were conducted. Scanning Electron Microscopy (SEM) was used for characterizing the scale thickness. Specimens with iron carbonate scales were mounted in epoxy resin and then cross sectioned and polished. The specimens were mounted in epoxy resin to protect scale integrity during sectioning and surface preparation.

4 XII-4 EROSION/CORROSION RESEARCH CENTER The solid particle erosion resistance of FeCO 3 scale was characterized by direct impingement experiments as shown in Figure XII-3. In these experiments, pre-scaled specimens were targeted with sand particles at controlled gas velocities and sand feeding rates. Air was used as a carrying medium for the sand particles. An average sand particle size of 150-micron was used throughout the experiments. Testing was conducted on dry FeCO 3 scale and on water-wetted scale. For testing of dry scale, dry sand was fed into the side port of the fixture shown in Figure XII-3. For testing of wetted scales, a water-sand mixture was fed into the fixture. For dry scale tests, gas velocities of 23 m/s, and 36.4 m/s were used while for wetted scale tests, 36.4 m/s and 72 m/s gas velocities were used. Tests were conducted at impact angles of 30, 60, and 90 degrees. In these tests, specimens were subjected to several short periods (trials) of sand impingement, each with a known mass of sand. The weight loss due to scale removal was measured after each trial. The cumulative weight losses were plotted versus sand throughputs to determine the erosion ratio. The erosion ratio, i.e., the mass of scale removed to the mass of sand applied, was determined by the slope of the data. The erosion ratio provides a measure of the erosion resistance of the scale. Dry Sand / Sand-Water Mixture Air Figure XII-3: Direct Impingement Test Modeling Work A mechanistic model for predicting erosion-corrosion rate was developed by modifying and integrating an existing CO 2 corrosion prediction model [1] and a sand particle erosion model [2]. The integration process and the planned modifications to both models are discussed in this section. For the CO 2 corrosion prediction model, sub-models were developed to calculate scale precipitation rate, scale build up rate and diffusion of species through the scale. The sub-models were incorporated into the computer program that implements the CO 2 corrosion model. For the sand particle erosion model, an equation representing the erosion resistance

5 EROSION-CORROSION MODELING AND EXPERIMENTS XII-5 of FeCO 3 scale has been developed and incorporated into the computer program that implements the erosion model. The sub-models are described below: Modeling Scale Precipitation Rate Accounting for the precipitation rate of FeCO 3 is very important component of the new erosion-corrosion model under development. FeCO 3 precipitation rate models available in the literature were sought. Three models were found in the literature for modeling scale precipitation rate. The first model was proposed by Johnson and Tomson [3]. The authors developed an empirical correlation that relates iron precipitation rate to super saturation SS, FeCO 3 solubility limit, and reaction rate constants. The second precipitation model was proposed by Van Hunnik et al. [4]. Hunnik and coworkers tested Johnson and Tomson s correlation outside the range of the experimental data considered in the original work. Accordingly, they proposed modifications to the original form to obtain a better fit to a wider range of experimental data. In the third model, Yean et al. [5], followed a more fundamental approach based on reaction kinetics. In Yean s approach, iron carbonate formation was treated as a first order reaction with respect to ferrous ion (Fe 2+ ). The instantaneous iron concentration in the solution was given by Equation (1). (1) where [Fe] t is the total dissolved iron concentration at time t in (mol/l); [Fe] EQ is the equilibrium concentration of iron in (mol/l); [Fe] o is the initial total dissolved iron concentration at t = 0 in (mol/l); t is time in (minutes); and k is the first order reaction rate constant in (min -1 ). The first order reaction rate constant was given by the Arrhenius Equation (2). (2) where A is pre-exponential factor or frequency factor in (min -1 ); E a is the activation energy in (kj/mol); R is the gas constant in (kj/mol. o k); and T is temperature in ( o k). The values for A and E a reported by Yean et al. were 3.85 x (min -1 ) and 197 kj/mol, respectively. Yean s model was incorporated into the research presented here for two reasons. First, it follows the kinetics of first order reaction and, second, it is very well supported by the experimental data. Yean s model given by Equation (1), has been recast in this work to include the solubility limit, K sp, CO concentration and boundary layer thickness, h bl. The

6 XII-6 EROSION/CORROSION RESEARCH CENTER h bl can be approximated by pipe roughness. The final form of the precipitation model is given by Equation (3). mole Fe m k [ ] ([ ][ ] 2+ 2 Fe CO k ) 2 3 sp CO 2+ & = ρliq h 2 bl m.s 3 (3) where ṁ is the precipitation rate of iron. The solubility limit, K sp, can be calculated by Equation (4) to account for temperature and ionic strength [6]. log log (4) where T is the temperature in Kelvin and I is the ionic strength of the solution that is given by 1 2 (5) where c i is the molar concentration of ion i (mol/l), z i is the charge number of that ion, and the sum is taken over all ions in the solution. Modeling The Scale Build-up Rate Knowing the scale precipitation rate ( ), the increment in scale thickness (Δh) can be calculated as a function of scale density and porosity as given by Equation (6). m& Δt Δh = ρ ε FeCO 3 ( 1 ) (6) where is the precipitation rate (kg/m 2. s), ρ FeCO3 is the density of the solid phase of the scale (kg/m 3 ), Δt is the time step and ε is the scale porosity. Single layer or multilayer approaches can be followed for computing scale growth. In a single layer approach, ion concentrations at the scale-metal interface for instance can be used to calculate precipitation rate, and then calculate the increment in scale thickness for each time step. However, a multilayer approach requires knowing ion concentrations at each layer. Due to the

7 EROSION-CORROSION MODELING AND EXPERIMENTS XII-7 complexity of the multilayer approach, the single layer approach was used as a starting point in this research. Modeling Diffusion through Iron Carbonate Scale Modeling diffusion processes through the scale is needed for computing ion concentrations and then corrosion and precipitation rates. The mass transfer rate is given by Equation (7). n D = Δ (7) Δx A C A where n A is the molar flux (mol/m 2.s); D is the diffusion coefficient (m 2 /s), Δx is the diffusion distance (m), and ΔC A is the concentration difference (mol/m 3 ). For porous media, the diffusion coefficient is known as the effective diffusion coefficient, D eff. There are several models available in the literature for estimating the effective diffusion coefficient in porous media. All models estimate D eff as a modification to the diffusion coefficient in the liquid phase (D bulk ) but they vary in degree of complexity [7-12]. The first, and simplest, form was proposed by Maxwell [7] in which the D eff is a linear function of D bulk and porosity. The most complex form of D eff was proposed by Grathwohl [11]. It is a function of D bulk, porosity, tortuosity and constrictivity factor. The tortuosity is a measure of the increase in the diffusion path due to porous scale structure and the constrictivity factor accounts for reduction in effective diffusion due to the increase in shear inside the pores. Considering the models available in the literature, the effective diffusion coefficient, used in this work, was selected as a function of the diffusion coefficient in the bulk of the solution (D bulk ), porosity (ε), tortuosity (τ) and an empirical constant (m) as given by Equation (8). ε m D eff = D bulk (8) τ For multilayer scale, the tortuosity is mathematically expressed in this research by Equation (9). Δ h τ = 1 + i (9) Δ h

8 XII-8 EROSION/CORROSION RESEARCH CENTER where ΣΔh i is the total scale thickness and Δh i is the representative thickness of a single scale layer. Developing the Erosion Equation for Iron Carbonate Scale The sand particle erosion model used in this work [2], computes the erosion rate as a function of particle shape, impingement velocity, impingement angle and the hardness of the target material. The E/CRC erosion equation with empirical values for carbon steel material was given by Ahlert [13] as shown in Equation (10). ( θ) n ER = AFsV p F (10) where ER is the erosion ratio, defined as the ratio of the mass of wall material removed to the mass of impacting particles; A is a wall material dependent constant, F s is a particle shape coefficient; n is an empirical constant; V p is the particle impingement velocity; and F(θ) is a function of the impingement angle. In this task, the erosion resistance data collected experimentally at different environmental conditions has been used to determine the velocity exponent, n. Erosion-Corrosion Model A flowchart of the erosion-corrosion model computational procedure is shown in Figure XII-4. The sequence of the computational process can be summarized in the following steps for thermodynamic conditions that are favorable for iron carbonate scale formation: Compute the erosion rate of the scale. Then compute formation rate of the scale and compare the formation rate of the scale to the erosion rate of the scale. If the formation rate is smaller than the erosion rate, then it is assumed that the scale cannot maintain itself and erosion-corrosion rate equals to the summation of the corrosion rate and erosion rate of bare metal. On the other hand, if the formation rate is greater than the erosion rate, the scale thickness, h, is incremented until the rate of scale formation is equal to the erosion rate of the scale. At this point, corrosion rate is computed for an iron carbonate scale of thickness, h, and erosion rate is zero.

9 EROSION-CORROSION MODELING AND EXPERIMENTS XII-9 Figure XII-4: Flow Chart of Erosion-Corrosion Model Computational Procedure Results and Discussion This section provides a summary and a discussion of the experimental results obtained in this research. Generating Iron Carbonate Scale Scales were formed in a single phase flow loop under two different flow configurations: channel flow and jet flow. Figure XII-5 shows a specimen s surface before and after scale formation. For channel flow, thick forms of scale were formed at ph values between 6.1 and 7.1 and temperatures between 65 o C and 93 o C. A thinner scale layer was formed at lower ph. However, for jet flow, thick scale was formed at ph values between 5.6 and 6.1 and temperatures between 65 o C and 88 o C. before the test after the test Figure XII-5: Specimen s Surface Before and After Scale Formation

10 XII-10 EROSION/CORROSION RESEARCH CENTER Real time corrosion rate measurements were collected throughout the scale formation process by means of a 3-electrode LPR configuration. The LPR data provided an indication of scale formation in the form of a significant drop in corrosion rate as shown in Figure XII Flow 1 2 Coupon 1 Coupon 2 Corrosion Rate (mpy) LPR Electrodes Time (hr) Figure XII-6. Real Time Corrosion Rate Measurements at 93 o C, ph 6.7, and 20 psig CO 2 Formation of iron carbonate was verified by X-Ray Diffraction (XRD). Figure XII-7 shows a typical XRD result for scale formed at 93 o C, ph 6.5, and 20 psig CO 2. Figure XII-7. XRD Results for Scale Formed at 93 o C, ph 6.5, and 20 psig CO 2

11 EROSION-CORROSION MODELING AND EXPERIMENTS XII-11 Iron carbonate scale characterize Scanning electron microscopy (SEM) was used to characterize the thickness of iron carbonate scale. Figure XII-8 shows SEM images of an epoxy mounted specimen with a scale generated in the jet flow test section at 79 o C, ph 6.7, and 20 psig CO 2. Figure XII-8: SEM Images (Magnification 260X) for a Scale that was formed at 79 o C, ph 5.9, 20 psig CO 2 and Jet Flow Table XII-2 shows thickness measurements for scales that were formed in channel flow and jet flow test configurations. For channel flow, scales were formed at ph values between 6.1 and 7.1 and temperatures between 65 and 93 o C. The thickness of scales formed in this test configuration ranges from 2 to 13 microns. For jet flow, thick scale was formed at ph values between 5.6 and 6.1 and temperatures between 65 and 88 o C. The thickness of scales formed in this test configuration ranges between 40 and 70 microns.

12 XII-12 EROSION/CORROSION RESEARCH CENTER Table XII-2. FeCO 3 Scale Thickness Measurements obtained by SEM T ( o C) Case No. ph NaHCO3 Tests No. Scale Thickness ppm (μm) I. Channel Flow Test Configuration II. Jet Flow Test Configuration Erosion Resistance Characterization The solid particle erosion resistance of FeCO 3 scale was characterized by direct impingement experiments with sand in dry and wetted scale testing. All erosion tests were conducted for scales that were formed in the channel flow test section at ph 6.7, temperature of 93 o C, 2 wt% NaCl, and CO 2 pressure of 20 psig. Figure XII-9 shows images of specimens with dry iron carbonate scale that were impacted with sand at 30 and 90 degrees. 90-degree impact 30-degree impact Figure XII-9: Specimens with Dry FeCO 3 Scale Impacted with Sand at 90-Degree (Normal Incidence) and 30-Degree (Grazing Incidence)

13 EROSION-CORROSION MODELING AND EXPERIMENTS XII-13 Figure XII-10 shows sample results for tests that were conducted with 150 micron sand at a 30-degree impingement angle and two gas velocities: 23 and 36.4 m/s. The data presented in Figure XII-10-a shows three erosion regions. The first region is the erosion of the scale layer and the last region is the erosion of bare metal after scale removal, and a transition region. Similar trends were observed at both velocities. Figure XII-10-b provides a closer look to the erosion region of the scale layer. At 23 m/s, the erosion ratio is mg-scale/g-sand. When the velocity increased from 23 m/s to 36.4 m/s the erosion ratio increased by a factor of three. Figure XII-10. Erosion Data for Specimens with Dry FeCO 3 Scale Layer Obtained with 150 Micron Sand at a 30-Degree Impingement Angle

14 XII-14 EROSION/CORROSION RESEARCH CENTER Erosion ratio data are shown in Figure XII-11-a and 11-b for dry FeCO 3 scale and bare CS1018, respectively. For FeCO 3 scale, the data shows that higher gas velocity results in higher erosion ratios. When the gas velocity increased from 23 to 36.4 m/s, the average erosion ratio increased by a factor of 2 (from 4.04E-5 to 8.05E-5). The highest erosion ratios were obtained at 30-degree impingement angle for both velocities. The average erosion ratios and respective gas velocities were used to determine the velocity exponent, n, for the erosion ratio equation given by Equation (10). For the collected data, the calculated velocity exponent was almost 1.5. Figure XII-11-b shows experimental and predicted erosion data for bare CS1018 for comparison with the FeCO 3 scale erosion ratio data. The erosion behavior suggested by the trend of the data agrees with erosion behavior of ductile material reported by other investigators [14, 15]. The experimental data shows that when the gas velocity increased from 23 to 36.4 m/s, the average erosion ratio increased by a factor of 3.3 (from 8.13E-7 to 2.69E-6). The highest erosion ratios were obtained at 30-degree impact angles for both velocities. The calculated velocity exponent for the collected data is 2.6. Using erosion equation, Equation (10), erosion ratios for the CS1018 were predicted. Predictions were made with velocity exponent of 2.4 instead of 2.6 as the former was supported by a larger amount of experimental data. Predicted erosion ratio values, shown by continuous lines, show agreement with the trends of the experimental data at both gas velocities.

15 EROSION-CORROSION MODELING AND EXPERIMENTS XII-15 a. Experimental Erosion Data for FeCO 3 Scale Erosion Ratio, ER (g scale/g sand) 1.2E 4 1.0E 4 8.0E 5 6.0E 5 4.0E 5 2.0E 5 0.0E+0 Erosion 36.4 m/s Erosion 23 m/s Impact Angle (θ) b. Predicted and Experimental Erosion Data for CS E E 06 Erosion 36.4 m/s Erosion Ratio (g/g) 4.0E E E 06 Equation 23 m/s Equation 36.4 m/s 1.0E E+00 Erosion 23 m/s Impact Angle (θ) Figure XII-11: Erosion Ratio Data Using 150 Micron Sand for a) Dry FeCO 3 and b) CS1018 The erosion ratios for various impact angles are shown in Figure XII-12 for wetted FeCO 3 scale and wetted 13Cr. 13Cr was used here instead of CS1018 for two reasons. First, the CS1018 would corrode under these test conditions and second, the erosion resistance for

16 XII-16 EROSION/CORROSION RESEARCH CENTER 13Cr is close to that of CS1018. For FeCO 3 scale, the data has some degree of scattering so average erosion ratio values were used to determine the velocity exponent. When the gas velocity increased from 36.4 to 61 m/s the average erosion ratio increased by a factor of about 6 (from 1.24E-5 to 7.39E-5). For the collected data, the velocity exponent is about 3. For 13Cr bare metal, when the gas velocity increased from 36.4 to 61 m/s the average erosion ratio increased by a factor of 9 (1.81E-7E-7 to 1.68E-6). At a gas velocity of 61 m/s, the highest erosion ratio was obtained at a 30-degree impingement angle and the lowest was obtained at 90-degree. At 36.4 m/s there was less dependency on impingement angle. The velocity exponent for the 13Cr data was 4.2. Another parameter of interest here was how the erosion ratio for the scale compares to the erosion ratio for bare steel. For dry sand data, the erosion ratio factor, Equation (11), was 30 at a gas velocity of 36.4 m/s and 50 at a gas velocity of 23 m/s. For wetted scale and wetted 13Cr, the erosion ratio factor was 68 at a gas velocity of 36.4 m/s and 44 at a gas velocity of 62 m/s Erosion Ratio Erosion Ratio Factor = Erosion Ratio of of Scale Bare Metal (11)

17 EROSION-CORROSION MODELING AND EXPERIMENTS XII-17 a. Erosion Ratio Data for FeCO 3 Scale Erosion Ratio (ER) 1.0E E E E E 05 Erosion Ratio 62 m/s Erosion Ratio 36.4 m/s 0.0E Impact Angle (θ) b. Erosion Ratio Data for 13Cr Erosion Ratio (ER) 2.5E 6 2.0E 6 1.5E 6 1.0E 6 5.0E 7 Erosion Ratio 36.4 m/s Erosion Ratio 62 m/s 0.0E Impact Angle (θ) Figure XII-12. Erosion Ratio Data Using 150 Micron Sand for a) Wetted FeCO 3 and b) Wetted 13Cr

18 XII-18 EROSION/CORROSION RESEARCH CENTER A Sample Calculation For The Erosion-Corrosion Model A sample calculation for the model is shown in Figure XII-13 to illustrate the procedure for a case where the initial formation rate of the scale is greater than the erosion rate of the scale. For flow conditions shown in Figure XII-13-a, the erosion-corrosion model predicts that iron carbonate scale should form. The erosion rate of the scale was then predicted using the erosion model. Figure XII-13-b shows the erosion rate of the scale computed for a range of gas superficial velocities. For a gas superficial velocity of 10 m/s, the erosion rate of the scale was predicted to be 0.27 mm/y. Next, the steady-state scale thickness was calculated. The steady-state scale thickness is the thickness at which the formation rate of the scale equals the erosion rate of the scale. Figure XII-13-c shows the formation rate of the scale computed over a range of scale thicknesses. For a formation rate of the scale equal to 0.27 mm/y (equal to the predicted erosion rate), the steady-state scale thickness was predicted to be 6 microns. Finally, the corrosion rate was calculated for the steady-state scale thickness of 6 microns. Figure XII-13-d shows the corrosion rate computed over a range of scale thicknesses. For a 6 micron scale thickness, the predicted corrosion rate was 1 mm/yr.

19 EROSION-CORROSION MODELING AND EXPERIMENTS XII-19 a. Step 1: Predict iron carbonate scale formation Result: This is a scale forming condition as predicted by E C model b. Step 2: Compute erosion rate of the scale at (V sl = 3m/s, V sg =10 m/s) Result: ER SCALE = 0.27 mm/y T 90 o C P CO 2 V sl V sg 4.5 bar 3.0 m/s 10.0 m/s ph 5.9 Sand Rate 200 kg/day Solution [Fe 2+ ]= 10 ppm, NaCl =3 wt% Erosion Rate (ERSCALE) mm/y ER SCALE V sg Gas Superfical Velocity (m/s) c. Step 3: Compute the steady state scale thickness d. Step 4: Compute corrosion rate (CR S S ) at steadystate scale thickness RESULT: h scale = 6 μm Result: CR S S =1 mm/y Scale Thickness (h) μm h scale FR = 0.27mm/y Scale Formation Rate (FR) mm/y Corrosion Rate (mm/y) CR S S h scale = 6μm Scale Thickness (h) μm Figure XII-13. Calculation Procedure and Sample Results of the Erosion-Corrosion Model

20 XII-20 EROSION/CORROSION RESEARCH CENTER Summary A mechanistic approach for predicting metal loss due to sand erosion and CO 2 corrosion of carbon steel has been developed in this research. This approach accounts for iron carbonate (FeCO 3 ) scale formation in multiphase flow by modeling the competition between scale growth by precipitation and scale removal by erosion. Models from the literature for quantifying iron carbonate scale precipitation and growth rates, and diffusion rates of cathodic reactants and corrosion product species through iron carbonate scale have been adapted to this purpose. The solid particle erosion resistance of FeCO 3 scales has been characterized by direct impingement experiments. Literature and laboratory results, along with a CO 2 corrosion rate prediction model (SPPS: CO2) and a sand erosion rate prediction model (SPPS) developed by the Erosion/Corrosion Research Center, have been integrated into a single mechanistic model for predicting erosion-corrosion under steady-state conditions. For future work, corrosion tests for forming FeCO 3 scale at wider ranges of environmental and flow conditions will be conducted, solid particle erosion resistance testing of iron carbonate scale will be continued, and multiphase erosion-corrosion tests for validating the final erosion-corrosion prediction model will be conducted

21 EROSION-CORROSION MODELING AND EXPERIMENTS XII-21 References 1. Shadley, J.R., et al., Prediction of Erosion-Corrosion Penetration Rate in a Carbon Dioxide Environment with Sand. Corrosion, (12): p Shirazi, S.A., et al., Generalization of the API RP 14E guideline for erosive services. Journal of Petroleum Technology, (8): p Johnson, M. and M.B. Tomson, Ferrous Carbonate Precipitation Kinetics and Its Impact on CO 2 Corrosion, in Corrosion/911991, NACE International: Houston. 4. Van Hunnik, E., B. Pots, and E. Hendriksen, The Formation of Protective FeCO 3 Corrosion Product Layers in CO 2 Corrosion, in Corrosion/ NACE International: Houston. 5. Yean, S., et al., Ferrous carbonate nucleation and inhibition, in SPE International Oilfield Scale Conference, 2008, Society of Petroleum Engineers: Aberdeen, UK. 6. Sun, W., S. Nešić, and R.C. Woollam, The effect of temperature and ionic strength on iron carbonate (FeCO3) solubility limit. Corrosion Science, (6): p Maxwell, J., A Treatise On Electricity And Magnetism. 3rd ed. Vol. 1. New York: Dover. 8. Cussler, E., Diffusion: Mass Transfer In Fluid Systems. Second ed1997: Cambridge University Press. 9. Gopal, M., R. Zhang, and S. Rajappa, Modeling the Diffusion Effects Through the Iron Carbonate Layer in the Carbon Dioxide Corrosion of Carbon Steel, in CORROSION , NACE International: San Diego Ca. 10. Crolet, J.L., N. Thevenot, and S. Nesic, Role of Conductive Corrosion Products in the Protectiveness of Corrosion Layers. Corrosion, (3): p Grathwohl, P., Diffusion In Natural Porous Media: Contaminant Transport, Sorption/Desorption And Dissolution Kinetics1998: kluwer Academic Publishers. 12. Mu, D., et al., Determination of the effective diffusion coefficient in porous media including Knudsen effects. Microfluidics and Nanofluidics, (3): p Ahlert, K., Effects of Particle Impingement Angle and Surface Wetting on Solid Particle Erosion of AISI 1018 Steel, in Department of Mechanical Engineering1994, The University of Tulsa: Tulsa, Oklahoma. 14. Finnie, I., Erosion of Surfaces by Solid Particles. Wear, (1): p

22 XII-22 EROSION/CORROSION RESEARCH CENTER 15. Finnie, I., Erosion of Metals, in Corrosion/Erosion of Coal Conversion System Materials1979, NACE: Berkeley. p