Laboratory study of the wear phenomenon of fluid containing sand in pipelines

Master thesis in the field of chemical engineering (no orientation)

Abstract

Laboratory study of the wear phenomenon of liquid containing sand in pipelines

In this work, to investigate the wear phenomenon caused by the movement of fluids Two phases are discussed in the pipelines. The studied fluid consists of two phases, liquid and solid. The liquid phase is water, and sand particles form the solid phase. In this research, the parameters affecting the wear rate, including: fluid speed, sand particle size, sand particle concentration, and the hardness and density of the target metal, have been studied. In order to obtain the amount of wear, disk coupons made of aluminum and steel have been used in six different places of the flow (according to the operating conditions of exploitation and transportation of petroleum materials). First, the liquid wear rate (single phase) is measured in the six mentioned places, and in the next step, the study of liquid wear containing solid particles of sand is investigated. At each stage, the obtained results are compared with the values ??determined by the existing standards and solutions are provided. Then, using the test data and genetic algorithm in MATLAB (Differential Evolution method), a suitable mathematical model is presented to calculate the wear rate. The comparison of mathematical model and laboratory data shows that this model has a good ability to express experimental data.

Key words: wear of sand grains, coupon, wear rate, genetic algorithm

Introduction

1-1- The importance of wear and corrosion in the industry

The phenomena of corrosion [1] and wear [2] are considered as one of the important damages and challenges in the oil, gas and petrochemical industries. Corrosion phenomenon, by definition, is a chemical or electrochemical reaction between a material, usually a metal, and its surrounding environment, which will lead to a change in the properties of the material. Corrosion process in industry causes huge economic damage and many things can be done to reduce it. Some damages caused by corrosion include: unfavorable appearance (for example, car paint corrosion), maintenance and operation costs, factory shutdown, contamination of products, leakage or loss of valuable products such as hydrocarbon materials or leakage of tanks containing uranium. Considering that thermodynamically oxidized materials are at a lower level of energy compared to materials in a normal state, so the tendency to reach a lower energy level causes the metal to oxidize (corrode). Corrosion is a spontaneous process, that is, in thermodynamic terms, it moves in a direction to reach a stable state.

Corrosion phenomenon occurs in all main categories of materials, including metals, ceramics, polymers and composites, but its occurrence in metals is so common and widespread and it leaves destructive effects that whenever we talk about corrosion comes, the corrosion of a metal comes to mind unconsciously.

Abrasion is the process of material separation from the metal surface as a result of mechanical reaction. Such as the impact of solid particles together with gas and liquid, or due to the impact of liquid droplets on the inner wall of the fluid passing channel. Abrasion caused by pipelines containing slurry for transporting solid raw materials such as iron ore, coal and potash is a big problem in the mining industry. Abrasion of pipelines for the transportation of food grains and corn as an alternative to transportation with belts and conveyors is one of the topics investigated in the agricultural industry. Items in the industry that are the phenomenon of Melmuster wear include: gas turbines, compressors and pumps, nozzles, transmission pipes and tubes, helicopter and airplane blades, transportation engines, etc. rtl;">Abrasion of pipelines and equipment used to transport fluids containing solid particles is a fundamental problem in many industries, including the oil and gas industry.Abrasion has been known for a long time as a source of problems in hydrocarbon production and exploitation systems. Many catastrophic failures of elbows in production platforms, drilling units and other subsea facilities in previous decades have been a result of wear. These problems and breakdowns include the cost of replacing worn out parts, as well as environmental problems and safety issues. When oil and gas are produced from reservoirs with relatively low resistance (less than 2000 psi), by reducing the reservoir pressure, sand particles can be separated from the reservoir rock and a number of particles can be produced along with fluids. These sand particles can cause the wear of pipelines and equipment and as a result lead to the stoppage of production, and therefore significant economic losses to oil and gas producers [2, 7].

Abrasion, in addition to causing equipment failure and increasing the estimated costs due to the purchase and relocation of equipment, can cause environmental pollution or fire due to holes and ruptures in the passageway of hydrocarbon materials. The rate of damage and loss of marine equipment is much higher than surface and ground equipment. Due to the world's need for energy (which is mostly provided by fossil fuels), the production of oil and gas (maximum production capacity) should be considered by the relevant companies. But in order to achieve more production, many problems arise, including wear. When the rate of extraction from the well is high and there are fine particles of sand and even dirt in the system, wear will be more destructive. Reducing the production flow of the well as a solution to reduce wear does not seem appropriate. Most of the underground reservoirs include oil, gas and water. Operation may be single-phase or multi-phase. The amount of wear in multi-phase flows in conditions similar to production capacity is much higher than single-phase flows [3].

Abstract

Experimental Study of Liquid & Sand Erosion in Pipe Lines

In this work the created erosion by the movement of two phase fluids in pipelines has been investigated. The main fluid consists of liquid and solid phase. The liquid phase is water, and the solid phase is sand particles. In this work, the effective parameters on erosion rate such as: fluid velocity, sand size, sand concentration, hardness and density of metal, have been studied. To find out the erosion rate, ring coupons of two kinds of carbon steel and aluminum in six different locations in pipe line (in accordance with operational production and oil material transition) have been employed.

At first, liquid erosion velocities (single phase) are measured in six locations. And in the next stage, erosion of two phase fluid has been evaluated. In each stage, the data which are obtained from experiments are compared with available standard data and some recommendations are proposed. Then a mathematical model for evaluation of erosion rate by means of experimental data and use of genetic algorithm in MATLAB software (differential evolution method) has been presented. By comparison of mathematical model with experimental data, we find out that the proposed model is able to predict the experimental data with good satisfaction.

Key words: sand erosion, ring coupon, erosion rate, genetic algorithm.