EXECUTIVE SUMMARY EXECUTIVE SUMMARY OF PROGRESS

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1 ES-1 EXECUTIVE SUMMARY OF PROGRESS The following is the executive summary of progress and/or presentations at the E/CRC meeting. Research Approach: Dr. Siamack A. Shirazi E/CRC has developed Erosion and Erosion-Corrosion computer programs that are available at the E/CRC web sites for E/CRC members. Sand Production Pipe Saver (SPPS) that is the E/CRC erosion prediction model (computer program) is being updated and evaluated. Current work at the E/CRC is to incorporate modifications that allow SPPS to handle multiphase flow more accurately. Experiments are being conducted in slug flow, low liquid loading gas flows and annular flows. Experiments are conducted varying particle size and liquid viscosity to model effects of particle size and viscosity more accurately. Current erosion models are being extended to fines (<50 microns particles) and viscous liquids. A 2-D version of SPPS has been developed that extend SPPS capabilities. The SPPS 2-D is also being extended to handle multiphase flow. E/CRC has developed a capability of predicting erosion in complex geometries utilizing a CFD based erosion model. The CFD based erosion model is also being validated for situations involving small particles and different fluid viscosities. The CO 2 corrosion model is available with MS Excel interface and has been extended to multiphase flow and is also available at the E/CRC website. Also, E/CRC has done significant research on erosion-corrosion of corrosion resistance alloys and guidelines and test results are available to the members of E/CRC. A computer program that was previously developed to predict erosion-corrosion of carbon steels is currently being updated in Excel with VBA to include current version of SPPS and SPPS-CO 2 for multiphase flow. Experiments under multiphase flow conditions will be conducted to verify and refine the model. Petrobras has sponsored a project at E/CRC to examine effects of sand and an oil phase on an inhibitor performance. The project is developing equations that can be used to determine inhibitor effectiveness as erosivity and corrosivity are varied. Petrobras is allowing the results to be incorporated to the Erosion-Corrosion computer program that is being developed at the E/CRC.

2 ES-2 EROSION/CORROSION RESEARCH CENTER Status of SPPS and User Manual: Dr. Brenton S. McLaury SPPS v4.2 is the latest version of SPPS, which also has an accompanying updated user s manual. This version contains a variety of models to calculate thickness loss rate (penetration rate) in several geometries. SPPS utilizes particle tracking to determine particle impact velocities that are then used in erosion equations to determine erosion. The traditional approach in SPPS applies a one-dimensional (1D) particle routine; however, this approach is deficient for small particles and high density flows. So, a twodimensional (2D) approach is now also available that comes closer to replicating computational fluid dynamic (CFD) simulation results. The 2D models also have the added features of an updated erosion equation and turbulent particle dispersion. For multiphase flows, the 1D model has the options of flow regime independent and flow regime dependent models. The flow regime independent models use mixture properties for the fluid properties and utilize an expression that is a function of superficial gas and liquid velocities to represent the velocity of the flow. The flow regime dependent models are specific to a given flow regime (flow pattern). For the 1D approach, the following flow regimes are available: mist (very low liquid high gas), annular, slug, churn and bubble flows. In the upcoming version (SPPS v4.3 beta), only the flow regime independent approach will be available for the 2D model. There were many modifications in the coding for SPPS v4.2. This work was done to make SPPS more reliable and more uniform for future updates. Most of this work does not affect the use of the program. However, there is one modification that affects use. SPPS is no longer one Excel file. A.zip file must be downloaded from the website and extracted. Since flow solutions stored for the 2D geometries are very large, it became necessary to separate them into another file. Current work is also being performed to use the updated erosion equation in the 1D model. The previous erosion equation provides erosion predictions that are often overly conservative. Since previous models developed for specific flow regimes were based on the previous erosion equation, simultaneous development of these flow regime specific models is being performed. Erosion in Slug Flow: Netaji Ravikiran Kesana, PhD Student Erosion is a common problem faced by oil and gas industries, and the repair of pipeline fittings damaged by erosion is extremely costly. Therefore measuring erosion under different flow conditions and in different flow geometries is important to help better understand the effect of various parameters on erosion and to provide information to develop protective guidelines for the oil and gas producers. 0

3 ES-3 To better understand the location of maximum erosion inside the 3 inch bend we implemented a new technology called Multipoint Thickness Measurement Using Ultrasonic Transducers. The ultrasonic transducers are mounted at 16 locations on the outside bend of the elbow which allows the measurement of erosion pattern under different operating conditions. Specifically, erosion experiments have been conducted for single-phase (gas) and multiphase flow patterns (slug and mist flows) in the horizontal orientation. The experiments were performed with air and water as the fluids and using 150 and 300 micron particle sizes with 1 % concentration by weight. Results demonstrate the location of the higher erosion on the elbow under considered flow patterns. Interestingly, the location of highest erosion that we are measuring for horizontal slug flow is on the top surface of the bend (12:00 O clock position) and for the other flow patterns the location of maximum erosion is on the outer radius of the bend near the 45 degree position. In order to find out the reason behind observing higher metal loss at the top of the bend in the slug flow regime, we have conducted the sand sampling experiments inside the bend using the probes flush mounted to the inside wall of the pipe. We found that from the sand distribution results, there is more sand at the top of the bend. Also, the liquid distribution profile in the cross section of the bend shows that there is a little liquid present at the top of the bend. More sand and little liquid at the top of the bend is causing more metal loss. To improve the slug flow erosion model incorporated into the SPPS, we are also planning to study slug characteristics, such as slug body length, liquid-hold up in the slug body and slug frequency by analyzing the vast amount of data collected using Wire Mesh Sensor (WMS). Previous investigators suggested that steady state slug body will not have a constant length and it follows a log-normal distribution. Earlier experiments conducted were at lower superficial gas velocities and there is a lack of experimental data on slug characteristics under which we performed our erosion measurements. Flow Loop Study for Developing an Erosion-Corrosion Rate Prediction Model in Presence of Inhibitor and Oil Dr. Shokrollah Hassani (Project supported by Petrobras) Corrosion has an important impact on the total cost of oil and gas production. From the diversity of corrosion related problems, CO 2 corrosion (sweet corrosion) is probably the material degradation mechanism most extensively assessed in this industry for the last 30 years. Chemical inhibition is one of the most effective and popular techniques in controlling corrosion in oil and gas production and distribution. Different mechanistic and empirical models are available to predict the CO 2 corrosion as a function of different parameters including CO 2 pressure, temperature, ph, chloride content, and etc. However, sand production during oil and gas production affects the chemical inhibition efficiency. Previous research at the E/CRC on inhibited erosion-corrosion has shown that low corrosion rates in inhibited systems can increase to unacceptable levels when sand production starts. Therefore, available models for prediction of CO 2 corrosion have

4 ES-4 EROSION/CORROSION RESEARCH CENTER to be modified for the effect of sand production on CO 2 corrosion especially in the presence of chemical inhibition. In a recent erosion-corrosion research for PETROBRAS, research was directed towards quantifying the effect that erosivity has on inhibitor efficiency under selected environmental conditions. Data accumulated in this research was used to develop a framework for prediction of inhibitor efficiency in erosive flows that will allow one to predict, for selected environmental conditions, inhibitor efficiency as a function of erosivity and inhibitor concentration. PETROBRAS has agreed to make the results of this work available to improve E/CRC erosion and erosion-corrosion prediction programs, SPPS and SPPS:E-C. Corrosion and erosion-corrosion rates as baseline data for this study were produced in flow loop testing using EIS, LPR, Long-term weight loss, Potentiodynamic polarization, and 3D profilometer methods over a wide range of inhibitor concentrations (i.e. 0 ppm, 10 ppm, 25 ppm, 50 ppm, 100 ppm, 150 ppm, and 250 ppm) in four different sets of ph, two sets of temperature, two different water cut, and three different erosivities. After producing the baseline data, inhibitor surface coverage was calculated based on corrosion rate information. Relations between inhibitor concentration and inhibitor surface coverage were fitted to different inhibitor adsorption isotherms (i.e. Langmuir, Frumkin, Temkin, and Flory-Huggins) and the best fit was selected to describe inhibitor adsorption behavior in flows containing sand. Inhibitor adsorption isotherm was integrated into the E/CRC mechanistic model for prediction of CO 2 corrosion rate. Experimental erosion-corrosion test results in the presence of inhibitor, the existing E/CRC erosion model and erosion-corrosion model, and inhibitor adsorption isotherms were used to predict erosion-corrosion rate as a function of inhibitor concentration. A framework and also a model for prediction of erosion-corrosion in the presence of inhibitor and sand were developed in this research. A computer program has also developed for PETROBRAS Company for prediction of inhibited erosion-corrosion rate as a function of different corrosivity and erosivity variables. For future work, a new test section has been designed for erosion-corrosion study at low erosivity and low water cut conditions which enable us to monitor total erosioncorrosion, pure erosion, and also corrosion part of erosion-corrosion during the experiment. This new design will be used to examine, improve and validate the proposed model. Effects of Viscosity and Particle Size on Erosion Measurement and Prediction: Sai Abhishek Nidasanametla and Amir Mansouri (New PhD Student) When oil and gas are removed from reservoirs, they usually contain impurities such as small sand particles. These particles impinge the wall of the pipes that gas and oil are carried in and damage the wall. This damage is called erosion. In order to prevent erosion damage, many industries are using erosion models to predict when the pipeline 0

5 ES-5 and fittings are going to fail due to erosion. The Erosion/Corrosion Research Center (E/CRC) at the University of Tulsa has conducted research on erosion and corrosion occurring under a range of conditions and pipe geometries. One of the main goals of E/CRC is to develop the software called Sand Production Pipe Saver (SPPS) which can predict erosion for a certain geometry and set of conditions. This software can be used as a guideline by the oil and gas industries. Erosion rates have been measured for 50, 150 and 350 µm spherical glass beads in air. The target material is Aluminum T6. The particle velocities tested are 24 and 42 m/s. The results showed that erosion is not significantly affected by particle size as long as the particles have the same impact speeds. A new erosion equation has been generated based on these results and implemented into a commercially available Computational Fluid Dynamics (CFD) code to predict erosion rates for a variety of flow conditions, flow geometries, and particle sizes. Concurrently, the erosion rate of the same material with a direct impingement geometry using 50, 150 and 350 µm glass beads are measured in liquid of various viscosities. The nozzle average liquid exit velocity was maintained at 10 m/s and carrier of viscosities 1, 10 and 30 cp are used. CFD analyses are performed in order to predict erosion rate in a same geometry. The erosion results showed that for the range of viscosities considered, larger particles produced higher erosion rates than smaller particles. CFD results showed that CFD tends to under-predict erosion rates for 150 and 350 µm particles while it tends to over-predict erosion rates for 50 µm. Comparison of sand and glass beads erosion results revealed that the shape of the particle only affects the erosion rate by magnitude but not the trend respect to change in viscosity. Therefore, it was proved that the discrepancy between CFD calculation and measurement is not due to the shape of particles. The effects of grid size, dimensions and turbulence models on the accuracy of CFD calculations have been studied. It was found that two-dimensional and threedimensional meshes yield the same erosion rates, the grid size affects CFD predictions for smaller particle sizes, and the turbulence models affect erosion rates for higher viscosities. Particle behavior near the wall was studied and it explains the differences in predictions are due to the number of particle impacts and average particle velocity. Future work will be conducted for additional CFD assessment to make sure CFD results are accurate. Small Particle Erosion: Fardis Najafi Fard The effect of the particle size on erosion has been investigated by researchers at the E/CRC, but in most cases, erosion from relatively small particles has not been consider nearly often as erosion from larger particles. However, recent experimental studies by the E/CRC show small, sharp particles can cause severe erosion in both gas and liquid systems. These small sands pass through gravel packs and cause erosion without

6 ES-6 EROSION/CORROSION RESEARCH CENTER being detected by acoustic sand monitors. It has been seen that usually erosion form small particles occurs in geometries with high turbulence or recalculating regions. These types of geometries are found in piping systems, chokes and valves. New experimental facilities at E/CRC allow researchers to conduct small particle erosion in gas. Direct impingement geometry was chosen due to its simplicity. Erosion from small particles is comparable with relatively larger particles in this geometry. Erosion results from these experiments were used by E/CRC researchers to develop a more accurate erosion model for small particles. Previous erosion equations over predicts the magnitude of small particles erosion in sudden contraction/expansion geometry by factor of 20 to 40 in liquid dominated system. Using new E/CRC erosion equation for small particles eliminates this over prediction at throat and reduces it to the factor of 4-6 after sudden expansion. This over prediction is due to the unphysical multiple impacts which occurs in liquid dominated systems. Currently commercial CFD code (FLUENT 6.3) is used at E/CRC for flow simulation and particle tracking. In CFD code eddy size is limited by cell size. So having larger cells (coarser mesh) results in having larger eddies. Due to the fact that in sudden contraction expansion geometries, eddies have a huge effect on particle behavior, Having larger eddies changes particles behavior and results in changing erosion prediction. Also CFD predicts that small particles which enter viscose sub-layer, tend to stay and hit the wall over and over in a really small area with almost constant impact velocity. This nonphysical behavior results in over prediction of erosion magnitude. Erosion sensitivity study on sudden expansion geometry shows initial particles boundary conditions and particles size playing an important role in CFD erosion prediction in gas. By changing initial particles boundary conditions, CFD prediction changes from not predicting any erosion to predicting erosion close to experimental data in this geometry. To overcome commercial CFD code problems, a separate particle tracking code is being developed. Since FLUENT correctly predict flow solution so flow solution is obtained in FLUENT and exported to E/CRC particle tracking code. Using E/CRC particle tracking code allows us to predict particle trajectories and resulting erosion. Since the current E/CRC particle tracking code is preliminary, more study is needed to examine the current particle tracking code. Due to the fact that small particles cause severe erosion in geometries with high turbulence and re-circulation area, developing an accurate erosion model is necessary. Eventually, new developments in CFD-based erosion modeling will be used to improve SPPS 2-D. 0

7 ES-7 Erosion-Corrosion Prediction Modeling: Faisal Al-Mutahar, PhD Candidate In the oil and gas production industry, carbon steel tubing and piping are susceptible to erosion-corrosion due to the erosive and corrosive nature of the flow. The combined effect of sand erosion and corrosion can be very significant. In this research, the effects of erosion-corrosion of carbon steel, due to sand and CO 2, are being studied for multiphase flow. Two different Erosion-corrosion mechanisms are being considered. The first is erosion-corrosion mechanism for non scale-forming (FeCO 3 ) conditions, and the second for scale-forming conditions. Existing E/CRC models for erosion and CO 2 corrosion have provided the foundation for the new Erosion-Corrosion model. The main contribution of this research can be summarized in three points: 1) Developing a mechanistic model of the competition between FeCO 3 scale growth by precipitation and scale removal by erosion, 2) Developing a procedure for prediction of erosion-corrosion in oil and gas production and transportation systems, and 3) Developing a computer program for predicting the erosion-corrosion penetration rate. The erosion-corrosion model has been developed by building on the E/CRC models SPPS:CO 2 and SPPS, drawing upon the technical literature on FeCO 3 scale formation where available, and conducting experiments on scale properties relevant to scale structure and erosion resistance. FeCO 3 scales, produced under a range of environmental conditions, have been characterized with respect to scale structure, thickness and erosion resistance. Models from the literature have been evaluated for quantifying iron carbonate scale precipitation and growth rates and for diffusion through the scale. Single phase flow erosion-corrosion data has been obtained from laboratory flow loops for evaluating and validating the model. For the scale characterization experiments, the effect of geometry, temperature, and ph on scale formation were examined. Iron carbonate scales were formed in single-phase flow loops at a range of environmental conditions. Specifically, scales were formed in jet impingement and channel flow geometries, at ph range of , temperature range of o F, 2% by weight NaCl, and 34 psia CO 2 pressure. The experimental results showed a pronounce effect of flow geometry in the scale structure. The scales formed in jet flow were thicker and less protective i.e. more porous than the scales formed in channel flow. The test results showed also that scales formed at lower temperatures and higher ph values had higher scale thickness and higher porosity. These observations can be attributed to the change in the supersaturation values resulting from the change in these parameters. Lower temperatures, lower ph values, and higher velocities decrease the supersturation which consequently led to formation of thicker and more porous scale. An extensive work was done in this research for characterizing the erosion resistance of iron carbonate scale. This was given a priority because scale erosion is a main

8 ES-8 EROSION/CORROSION RESEARCH CENTER component of the erosion-corrosion process of carbon steel in scale forming conditions. Characterization of the erosion resistance of iron carbonate scale was done by addressing the following questions: 1) Does the erosion behavior of the scale follow typical behavior of brittle, ductile or other material, 2) Does the erosion resistance of scale change by wetting, and 3) What is the ratio between average erosion ratios of FeCO3 scale to mild steel. To address these questions, erosion ratios for dry, wet, and submerged FeCO 3 scale were measured by direct impingement tests. Two forms of scales were pre-developed in single phase flow loop and then used for erosion tests. The first form has a scale thickness of 4-6 microns and the second form has a scale thickness of microns. The erosion ratio results have shown that the erosion behavior of the scale does not follow the typical behavior of brittle or ductile materials. It seems that iron carbonate scale has its own erosion behavior that changes with scale thickness. Collected data was used to calculate an Erosion Ratio Factor (ERF) that divides the erosion ratio for the scale by the erosion ratio for steel. Then the ERF for wetted surfaces (scale and bare steel) was compared to the ERF for dry surfaces (scale and bare steel). Pooling Erosion Ratio Factors for all data over all gas velocities and all impingement angles provided a body of data for ERF-dry surface having a mean value of 42.62, and a body of data for ERF-wetted surface having a mean value of A t-test with hypothesis that the true means are the same was conducted at significance level 0.05 yielding the result that the data collected so far does not provide strong evidence that the two means are different. If the Erosion Ratio Factor mean for wetted surfaces is not different from the Erosion Ratio Factor mean for the dry surfaces, then it follows that the erosion resistance mean for wetted scales is not different from the erosion resistance mean for the dry scales. A research version computer program has been developed for predicting erosioncorrosion penetration rate. Model predictions are being compared to limited experimental data. The comparison showed encouraging results. The model will be validated with larger body of single-phase and multiphase flow erosion-corrosion data for scale forming and non-scale forming conditions. Erosion Prediction Under Low Liquid Loading and Annular Flow Conditions: Ronald Vieira, PhD Student Low-liquid loading and annular gas-liquid flow conditions are commonly encountered in gas transportation pipelines. They may also occur in other production facilities as gas/condensate production systems. Experience gained from production of hydrocarbons has shown that severe degradation of production equipment may occur. Prediction of erosion in multiphase flow is a complex problem due to lack of accurate models for calculating particle impact velocities that cause erosion. The particle impact velocity is affected by the pipe geometry, carrying fluid velocity, flow pattern, particle size and distribution in the flow. The complexity of erosion prediction increases 0

9 ES-9 significantly for two-phase flow in elbows because of complicated flow patterns that occur when both liquid and gas are present in the flow. Among different flow patterns in horizontal and vertical flows, erosion is most severe when particles are transported in gas dominant systems such as low liquid loading gas and annular flows. Recent experiments have shown that for annular flows erosion does not consistently decreases with an increase in liquid rate for a given gas rate. In order to examine the location of maximum erosion for annular flows in 76.2 mm (3") bends, an ultrasonic technique is being used. Sixteen ultrasonic transducers are mounted at sixteen locations on the outside radius of a stainless steel elbow which allows the measurement of erosion pattern under different operating conditions. Erosion experiments have been conducted for annular flows in vertical and horizontal orientations. The experiments were performed with air and water as the fluids and using 300 micron particle sizes with 1 % concentration (weight of solids/weight of carrier liquid). Results show that the location of the higher erosion on the elbow under annular flows is on the outer radius of the bend near the 45 degree position. In order to confirm the results obtained, a new transducer configuration is proposed on the elbow. In addition, in order to better model the impacting sand rates and particle velocities in annular flows, new sand concentration samples have been collected in annular gasliquid flows for horizontal orientation in two different locations: at the upstream position of the bend and at 45 degrees on the elbow. Eight ports were used for collecting liquid and sand samples at each location. Results show considerable differences in sand concentration values and liquid film distributions for each sampling location. Also, wire mesh sensors were used to measure void fraction in horizontal annular flow. Future work also includes analyzing the data to validate and improve liquid film characteristics in the elbow. Accurate modeling of the liquid film is important to predict erosion in this flow regime. Liquid Impingement Erosion: Hadi Arabnejad, PhD Student In production and transportation of hydrocarbons pipe size and material is determined so that the flow velocity is below the erosional velocity and above the transport threshold velocity. The erosional velocity is defined as a flow velocity below which is safe to operate and beyond that erosion damage may occur. From economical aspect, this threshold applies a limit on the production rate, and reliable and accurate prediction of this value is of great importance. The American Petroleum Institute Recommended Practice 14E (API RP 14E) proposed an equation for determining gas-liquid mixture erosional flow velocity. Some authors believe that API equation is very simple and could be applied to predict complicated process of two-phase flow that is a function of different parameters. Also, some experimental results show that the predicted erosional velocities are very conservative.

10 ES-10 EROSION/CORROSION RESEARCH CENTER In order to recognize the liquid impingement erosion, a literature survey is being conducted which shows that some experimental studies has been done in other fields. In aerospace engineering, rain erosion is a similar phenomenon and also in power plant industries, turbine blades and steam pipeline are exposed to liquid droplet impingement erosion. There are two major types of experimental method to evaluate the material behavior in liquid droplet impact. In the first type, specimen is mounted on a rotating disk or arm and cut liquid jet or liquid droplet stream. In the second type, liquid jet or droplets are accelerated to hit a fixed specimen. Experimental results show that, there is a significant difference between the results provided by these two types of experiments. Moreover, in each type liquid droplets or continuous jet could be implemented to cause erosion and the results from these investigations are different. More survey is on the way to investigate which of these types of experiments are applicable to oil and gas industries and also to consider removal of corrosion products by means of liquid impact since they are normally more brittle than base materials. Erosion Equations for Oilfield Materials: Predicting erosion by solid particles is of great importance to the oil and gas industries. Currently, erosion prediction models such as CFD based erosion models and E/CRC SPPS rely on empirical erosion equations, particularly for engineering materials. Previously, simple erosion equations were obtained and were implemented into SPPS. These equations were based on average and/or maximum values of erosion based on wet impact testing. This research work focuses on development of erosion equations for several oilfield materials, such as 22 Chromium, Chrome Duplex, 1018 Carbon Steel, 4130 Carbon Steel, Inconel 625 and 316 SS. Experimental data will be used to develop new erosion equations that account for impact angles, and these equations will be used in SPPS and CFD to optimize erosion prediction. Several hundreds of direct impingement tests were performed with these materials metal coupons for three different gas velocities, including 287 ft/s, 192 ft/s, and 96 ft/s. Particle velocity measurement with LDV were conducted to calculate actual particle impact velocities for these experiments. Experiments were conducted with 150 micron sand and constant sand rate of approximately 20 grams/min, impact angles range from 15 degrees to 30, 45, and 90 degrees. The weight of metal coupons were measured before and after each single test to determine weight losses, and the erosion ratio has been determined by plotting the weight loss against sand throughput. Then, erosion ratios for different test conditions were plotted for each material to determine the beast angle function that is used in the erosion equation. A new form of angle function was proposed based on Oka s work. The erosion equations predicted erosion ratios show a good agreement with the experimental data. 0

11 ES-11 In summary, erosion equations were developed from extensive experimental data and can be implemented into SPPS and CFD for more accurate prediction of erosion. Limited further tests will be conducted for larger (300 µm) or smaller (50 µm) particles. Also, erosion testing may be conducted with different types of particles and effects of particle hardness on erosion ratio equations will be investigated. Development and Validation of 2-D SPPS: (Recruiting a new PhD student for this project) Two dimensional particle tracking was introduced into SPPS to improve its accuracy in erosion prediction. It was reported that the overall performance of SPPS 2-D is much better than SPPS 1-D for cases with single carrier phase (sand/gas or sand/liquid flows) The primary goal of the current work is to extend its application to multiphase flows, i.e., sand/gas/liquid flows. The idea is to combine some multiphase flow models and the original SPPS 2-D for single phase flow. The multiphase flow models are utilized to determine flow regime and related flow parameters, such as annular film thickness, liquid holdup, slug flow characteristics, and so on. The problem is then simplified to single phase flow for the purpose of erosion prediction. The 2-D particle tracking for single phase flow is then applied to calculate particle trajectory and impact information. Erosion value can then be calculated using erosion equation. The presentation in May 2011 showed how SPPS 2-D is applied to predicting erosion in slug flow and annular flow. By comparing with experimental data found in the literature and collected at E/CRC and TUSMP, it is seen that the overall performance of SPPS 2- D is much better than SPPS 1-D. In the past one year, a lot effort has been put to optimize and re-organize the source code of SPPS. The flow field information database is now separated from the main program, making it easy to be distributed and upgraded. A progress bar showing the progress of the calculation is added so that the user can tell whether SPPS is working or freezes. One of the future works is to examine the capability of SPPS 2-D in predicting erosion for other flow regimes. Currently for annular flow, SPPS 2-D simply applies a liquid film to the geometry wall of interest, and conducts 2-D particle tracking in both gas core and the liquid film. Its performance has to be further examined and validated against more experimental data. For mist flow, it is correlated to the corresponding gas flow and annular flow. The model is discussed in another presentation. Applying SPPS 2-D along with this model is also one of the future works. For all other flow regimes, SPPS 2-D assumes it is single phase flow but uses mixture fluid properties in particle tracking. Again, experimental data is required to validate its performance.