OIL TRANSPORT AND PIPELINE PIGGING IN DEBRIS WAX REMOVAL

2 Objective of the thesis………………………………………………………. 3 Outline of thesis………………………………………………………………. 6 2 Pipeline Pigging Technology…………………………………………………………. 1 What is Pigging………………………………………………………………. 2 Early Pigging Technology…………………………………………………………. 8 Sphere Pig…………………………………………………………………. 4 Pig Selection…………………………………………………………………………. 5 Pig functions………………………………………………………………………. 1 Fluid separation…………………………………………………………. 2 Displacement……………………………………………………………. 3 Ice Pig……………………………………………………………………………35 4. Pigging as Inspection Tool………………………………………………………………36 4. 1Wax and Debris Removal……. Expected Development…………………………………………………………………. Conclusion………………………………………………………………………………. Oil refineries help in processing crude oil to give other byproducts such as gasoline, fuel oil, liquefied petroleum and other products like plastics, fertilizers, pharmaceuticals, and pesticides. The drilled and refined products are used as fuel to propel various machines in major industries in the drive of major global economies. Transportation of fossil fuel from the extraction to the final consumers majorly relies on the pipeline as the transport medium. Both domestic and industrial fossil fuel supply rely on the pipeline for its transport.

Since oil constitutes fifty percent of the fossil fuel and its volatility is high, its transportation requires pipeline which cannot cause rampant risks of catching fire during transportation unlike when other means are used. The pigs are used in various industries and the selection of the best pipeline pig demands an extensive and costly experience including knowledge of how pigging operates, the processes involved in pipeline pigging, and how can the pig be monitored. The pipeline pigging technology is required for the successful maintenances of pipeline industry (Jones, Smith, 2018). 2 Objectives of the thesis The objectives of the study sought to establish an in-depth understanding towards the technological methods involved in maintaining pipeline systems as a built up condition. Additionally, assessment of more developments that are expected to be integrated into the pipeline pigging to ensure proper pipeline maintenance over the coming years is considered in the thesis.

To examine the technical roles that pigging technology plays as a tool towards inspecting pipeline in order to enhance maintenance and management of pipes. Different physical principles are applied during the nondestructive testing of pipelines, each with its own set of advantages and disadvantages. Choosing the most suitable nondestructive testing technology and therefore in-line inspection tool for a given inspection task requires an understanding of these different techniques and their system-specific measurement thresholds, accuracies, and resolutions. This paper will provide an overview of the most widely used in-line inspection technologies of today, with a special focus on the use of ultrasound technology for the detection and sizing of metal loss, quantitative wall thickness measurement and crack inspection. Case examples will be used to illustrate the information that these tools can provide and the influence of accuracy, resolution and confidence levels on integrity assessment and fitness-for-purpose procedures.

Moreover, the research also relied on the objectives that will be achieved by the study upon assessments that are relevant in obtaining relevant information regarding fossil fuel transportation using the pipeline. Consideration of the measurement of current methods of cost estimation of pipeline management is captured in the study. PIPELINE PIGGING TECHNOLOGY Pipeline pigging technology involves a body of knowledge that applies the scientific understanding to enable efficient management and maintenance of pipelines when transporting products from the source to the final consumer. The technology is aimed at introducing a mechanism that prevents wastage, and which is cost-effective in sustaining long-term operations of the pipelines as they are used in transporting fluid, solid and gaseous substances. parameter General metal loss Pitting < 2t x2t Pitting ≥ 2t x2t Axial grooving Circumferential grooving pinhole Depth sizing accuracy at 80% certainty ± 0.

15t ± 0. 25t Width sizing accuracy at 80% certainty (mm) ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm Length sizing accuracy at 80% (mm) ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm Table 1 Anomaly detecting and sizing specifications of 6” and 8” tool 2. 1 What is Pigging? Pipeline pigging is a technology that uses the knowledge of polymers in applying coating substances to the internal part of a pipe to prevent corrosion and enhance pipeline life. The technology is used in the pipeline industry to aid in the maintenance of pipeline and enhances integrity via reduction of maintenance cost that is involved in Pipeline Company (Davidson, 2002, pp 1). Pipeline aids in the transport of powdered and fluid substances from various points across the world. In this line, therefore, the pipeline pigging is an important activity that is aimed at increasing the life cycle of the pipelines and their maintenance.

The replacement of rugs with leather bundles took effect over time and displayed the positive result as a result of the ability of leather to swell in moisture. The knowledge of leather bundle brought up the use of hydraulic control lines, straw bales among another mechanism for maintaining the lines for purposes of maximizing on cost (Davidson, 2002). The engineers have to choose from the varieties of the available pigs. The different pigs perform the same conventional function although their features differ. For instance, the gel pigs are composed of liquid gels that are highly viscous and are developed for purposes of pipeline operations. Continuous inspections and the maintenance of gas and oil pipelines are the requirements for their operations. The maximization of the operational time, cost, and life of the pipeline is the primary goal of the operator who is concerned with the design, installation and maintenance.

The reason why maximization of the operation is enhanced depends on the high cost connected with the processes of design, installation, and maintenance of the pipeline system. The life of the assets is must be factored to lasting longer as the purported design. The extended periods of the associated failures of pipelines can cause the health hazard to the operator and the financial constraints with regard to cash flow as an effect of prolonged periods of time (Davidson, 2002). The aim of launching the scrapper is to an elimination of clogging by erasing the corroded and heaped up materials within the pipes to enhance product flow via the pipeline. An assessment of the pipeline is done by running an intelligent pig that is repeatedly applied by use of acids and detergents.

Upon cleaning the interior of the pipes, a coating process begins in which the linings of the pipe are seamlessly coated to provide an efficient flow of products that are being transported. Revised and modified equipment used in pigging have contributed to a positive result with reference to pipeline maintenance since the application of thick film for coating purposes acts as internal barriers to corrosion. An internal lining of the pipe is created by the continuous application of pigging materials of thick films resulting to GRP structural creation in the interior of the pipe. Pigs are also important as they are able to help in checking the internal defects of the pipes such as roughness, roundness, thickness corrosion and leaks among other defects.

The problems caused in the interior walls of the pipe provides restrictions to flow of oil and other products hence lowering efficiency and increasing operation cost (Ohwoka, 2015, pp. A pig, therefore, is a cylindrical device that is fixed inside the pipe to help in cleaning the wax and debris which might prevent efficient flow of the products under transit. The process of fixing such devices coated with various components constitutes pigging. Pigging involves the practice of using pig device to undertake various operations regarding maintenance of the pipeline. The batching pigs are multipurpose and are used for purposes of separating products, scraping and cleaning the walls of the pipe. They are used for operations as a standard pigging. The functions to refill, and dehydrating the contents of the products being transported when hydrostatic testing is done.

The batching pigs are available in various sizes with a design customization including light cleaning and line filling. The batching pig is also referred to as swabbing pigs. The clean pigs having low-cost effects have been preferred for inspection purposes as they are helpful in determining deformities by the use of magnets unlike the internal detections of corrosions and pitting among other methods (Richard, 2018, p. 4 Magnetic Pig Magnetic pigs provide rooms for cleaning the pipe by moving wedding rods and electrode within the pipeline. Their design fits the removal of the ferrous debris that eliminates old construction debris and the products that result in corrosion. Powerful magnets are fitted at the circumference of the pig mandrel which acts as a secondary pig signaler activator.

The advancement attained in the magnetic pig provides the accurate determination of the corrosion effects and size. The specific use of materials in most intelligent pigs provides the electronic power while on board and sealed batteries. These pigs are capable of performing complex tasks which include logging of data during the transit of the products within the pipeline. Intelligent pigging allows for the measurement, mapping detection of cracks among other important tasks in the pipeline industry thus it forms a sub-industry within the main industry. 7 Gel Pig Gel pigs are used in cases where mechanical pigs cannot be used to perform the same task as the conventional mechanical pigging. The different medium of gels can be designed for a specific viscosity or a chemical component cast so that the component of the el can be broken down over time and at a given temperature.

Pigging as discussed above, have four main considerations in the pipeline industry. Therefore, the main reasons why pigging is required in the pipeline sector is to enhance in cleaning an interior of the pipes, batching or separation of products that are not similar is another importance of pigging, when a displacement of one or more products from others is required and for purposes of inspecting internal parts of the pipes. Despite the fact that there exist more functions of pigging and reasons why a company might want to pig pipes, most companies undertake to pig for either of the above reasons. Application of and reasons for pigging may depend on a number, variation or special purpose that is to be served by the pipe.

1 Fluid separation A polymer that is cross-linked is gelled with either water or hydrocarbon by the means of batch-mixed or continuous processes. A lamina flow calls for the total use of the batching ping when separating the products being transported because of the massive mixing that takes place in laminar flow. The batching pigs are multipurpose and are used for purposes of separating products, scraping and cleaning the walls of the pipe. They are used for operations as a standard pigging. The functions to refill, and dehydrating the contents of the products being transported when hydrostatic testing is done. The batching pigs are available in various sizes with a design customization including light cleaning and line filling. The decrease in flow and increased deposition of dirt may be invisible at first although they will be automatically identified by increased pressure, high bills of operation, reduced rates of flow, discharge of dirty products and a massive wearing down of the pigs (Schaefer, 1991, p.

Products flowing through the pipe require a maximum pressure to match the capacity of the line to increase flow efficiency and enhance cost-effectiveness. However, most of the day's pipeline operate at a lower capacity of the line thus reduce the flow rate which contributes to inefficiency and increased the cost of operation. The company may, in turn, realize a low-profit margin. Studies indicate that the corrosion caused by the debris within the walls of the pipe occurs in the lower quadrant of the sags. Inspection done to the pipe helps in identification of the stress and their effects on the pipes. Inline inspection is the best and the only method that is used to inspect a pipeline. The method of inspection provides coverage on the full volumes presence in the wall of the pip.

An understanding of the anomaly flow defects is critical in establishing the state of the pipes. The inspection should be an occasional undertaking prior to operation. Inspection requirement dictates the different sensor carrying designs and the configuration that is available for measuring crack detection in the walls of the pipes. For instance detection of cracks involves sensors that are aligned at a predetermined angle to the wall of the pipe leading to the ultrasound shear waves that travel at an angle of 45 degrees in the interior of the pipe. Inspection tools are configured according to the sizes of the individual pipeline via adaptation and the corresponding sensor carries that are available for intermediate size. Feasible processing time has enabled the detection of the defects within the pipeline to be real time.

The reading of the pipelines makes inspection accurate since the more the reading is done, the better the inspection thus a higher efficiency and reduced cost of operation will be enhanced. 4: Flow of Data Retrieval REASONS FOR PIGGING Pipeline operations require that pigging is done at every stage in the life cycle of a pipeline for commissioning, pre-commissioning, decommissioning and operational reasons. Pigging as discussed above, have four main considerations in the pipeline industry. Therefore, the main reasons why pigging is required in the pipeline sector is to enhance in cleaning the interior of the pipes, batching or separation of products that are not similar is another importance of pigging, when the displacement of one or more products from others is required and for purposes of inspecting internal parts of the pipes.

Despite the fact that there exist more functions of pigging and reasons why a company might want to pig pipes, most companies undertake to pig for either of the above reasons. Application of and reasons for pigging may depend on a number, variation or special purpose that is to be served by the pipe. 4 Decommissioning pigging The pipeline lifecycle is in most cases considered to be thirty or more years. The previously used pipes are recommended to be cleaned before they are excavated and new ones are fixed to replace them. The use of form pigs helps in the flushing out of the corrosion, wax and debris accumulation as well as other unwanted products present in the pipes. It is done to ensure that there are no presences of water and oil in the old pipe in the processes of excavation.

When there is need of changing the usage of the pipeline, the same process is applied to clean the pipes of any oil, water, or hydrocarbon that might be embedded in the walls of the pipeline. Continuous inspections and the maintenance of gas and oil pipelines are the requirements for their operations. The maximization of the operational time, cost, and life of the pipeline is the primary goal of the operator who is concerned with the design, installation and maintenance. The reason why maximization of the operation is enhanced depends on the high cost connected with the processes of design, installation, and maintenance of the pipeline system. The life of the assets is must be factored to lasting longer as the purported design.

The extended periods of the associated failures of pipelines can cause the health hazard to the operator and the financial constraints with regard to cash flow as an effect of prolonged periods of time (Davidson, 2002). For purposes of ease of disposal, the chemical might be injected into the pipeline when the gel leaves the pipe leading to the destruction of the viscoelasticity nature of the gel. The disgruntled gel can be pumped away for recycling into the system by addition of the base fluid or for further uses. Much of uses of gel pig is considered since water base or the debris gel pigs are known to be fully biodegradable and do not adversely affect the environment. The gel pig discharge has passed the test of PARCOM thus are recommended for discharge in UK marine environment, as well as approved landfills which harbor the disposed gel pigs in the case of inland piping (Uzu, 2000, pp 1).

2 Types of Gel Pigs In pipeline works, there are various types of gel pigs used to maintain the pipes and enhance cost-effective operation of those pipes. 3 Debris Pick-up Gel The loose debris is transported by all the pigs save at different efficiencies and at a variable loading level. The high viscosity of the debris pick-up gel that is flowing at a low rate allows the high yielding strength that makes the suspension of the debris possible even is conditions that require a prolonged lag time. The increase in debris loading allows for the increment of the plastic and debris yielding. The movement of the gel assumes a semi-solid pug that is higher than the capacity required for displacement to occur. The gel pig acts as a cleaning agent and exchange of the static gel closer to the walls of the pipe.

The purpose of incorporating the mechanical gel in paraffin solvent gel is to allow the gel solvent to penetrate better. 6 Isolation Gel Pig The design of the isolation gel is to ensure high sealing efficiency and prevention of flow across it. During the fluid maintenance, isolation gel pig is used to prevent invasion of fluid in the process of flagging operation 3. 7 Line filling/hydro testing gel pig An excellent seal of fluid within the walls of the pipe is formed when a mixture of mechanical and gel pig moves down the pipe. Hydro testing method of pigging assists in fluid separation as they push the line fill fluid or gases thus making the component conforms to the dimensions of the pipe.

During the freeze, the very low viscosity slug is used to reduce the rate of conventional current. It leads to a reduction in the cost of operation as well as simplified operation at the same time. A plug that thaws degrades are removed through the pipe after the completion of freeze operation. 9 Removal of the stuck pig The use of separator gel in line with mechanical pigs that displays increment in efficiency has called for the use of pigs to remove accumulated wax and debris scales. Nonetheless, the virtual elimination of mechanical pigs that are sticking on the gel-associated components is enhanced by the stuck remover pig. The ability of the ice pig to navigate a flow is sharp bents of the pipeline makes it critical to be used in piping maintenance and cleaning services.

The cleaning efficiency of the pipes is enhanced with this property of the ice pig technology. The technology allows the easy clouding of the ice pig to efficiently remove soft fouling using a volume of an ice that is one-tenth smaller than the volume of water in use (Quarini, 2002, p. Pigging is a process that involves not only cleaning but also the recovery of other products uniform pipes can have specific forms pushed through them with a constant diameter however the movement can be very difficult in negotiating bends or minor changes that occur within the cross-sectional area of the pipe. Flashing the content out of the pig is considered less effective compared with pigging. Figure 5: Ultrasonic crack detection tool Lots of regulations have outlined the requirements that an artificial intelligence method is applied for inland inspection.

The uses of intelligent inline inspection tools have increased efficiency, effectiveness, and commissioning of the pipelines inspection over lengthy pipelines within a limited time. Inline inspection is aimed at detecting the size of the pipe, locations and the defects that are present within the walls of the pipes. Pipeline integrity and inspection has initiated the use of pigging in monitoring, detecting, and making rectifications to the defects caused by the accumulated debris on the walls of the pipes which are responsible for reducing the efficiency and increasing the operational cost (Beller, 2012, p. Pipeline pigging is therefore used as the inspection tool for purposes of maintaining pipelines pipeline pigging can be used as an inspection tool I various ways such as geometric, metal loss as well as crack inspecting.

The turbulent flow, velocity, and temperature are closely independent with regards to the radial position of the pipes. Molecular diffusion and the shear dispersion are the methods that are involved in the fluid transport. A thin film of wax particle suspended in the pipe accelerates with the shear force of the surrounding fluid in the same direction as the fluid flow. The wall of the transporting file enhances the lateral flow of the suspended film of wax. The force that makes the wax to yield to the wax layer is known as the wax breaking force in which launching of the pig breaks the wax that is deposited in the pipeline. The kinetic process aids in the crystallization of the way through the classical homogeneous nucleation.

The thermodynamic problems are associated with modeling of the deposits resulting from kinetic modeling (Bern, et al. The modern pigging has greatly contributed to a clean pipeline transport in the sense that modern technology has explored and exploited almost all the necessary mechanism of maintaining pipelines as they are the most and reliable methods of transporting fluid, gas and solid products from the point of origin to the consumers. EXPECTED DEVELOPMENT The future expectation of the pipeline management, cleaning, and inspection aims at involving a technology that will develop software that monitors the image and display the flow. The software development is a milestone undertaking that is projected to be possibly realized in the few years to come. The current trends in testing different designs that take the structure of collapsible honeycomb shape have gained a milestone development as they will be able to navigate the most complex restrictions within the pipelines (Smith, 2018, p.

In addition, a mandrel body style tool that is disc-like mountable on the foam pig is an advancement in the pipeline pigging technology. The tool is able to identify the dents, deposition of wax and formation of scale. The disc enables the engineers to determine the volume of wax present in the pipeline. The development of types of sensors in which one type is able to fit in the collapsible foam pig and the other one fits into the new tool for pipelines with an ID of three inches and below is under construction (Johnes, Smith, 2018, p. The success of the study has been realized in the development of electronically modified tools that are able to withstand the environment in which pipelines are established.

The modern technology has settled for development of sensors that are capable of producing an equal amount of change within a time frame of five years. The future expectation of the pipeline management, cleaning, and inspection aims at involving a technology that will develop software that monitors the image and display the flow. The software development is a milestone undertaking that is projected to be possibly realized in the few years to come. The dream is fronted by several attempts in the field of technology and research. The process is possible in one pass through thus requires no repeated procedures in cleaning and commissioning pipes. Gel pig technology is crucial in the reduction of cost, time and environmental requirements for the completion of most services associated with the pipeline.

Compared with traditional methods of pigging, there is the provision of reliable information that can be measured to ascertain the degree of cleanliness using gel pig technology. The volume of debris removed can be analyzed from the contents that came out of the gel train. A fair estimation of the amount and components of the remaining debris is also made possible by the gel pig technology. International Journal of Multiple Flow, Volume Vol. 37, pp. Barbian Alfred and Beller Michael, 2012. In-Line Inspection of High-Pressure Transmission Pipelines: State-of-the-Art and Future Trends. Durban, The 18th World Conference on Nondestructive Testing, 16-20 Barbian Alfred and Beller, Michael, 2012. F. Schaefer, TSW. Pipeline Surveys, 1991. Pigging of the Subsea Pipelines. Texas, Jonathan, Southgare, 2004. Uzu, Obi, Napier, Roy and Nguwobia Kalu.

Gell Pig Technology Applications in Pipeline Servicing. The 24th SPE Nigeria Annual Technical Conference and Exhibition 1-5 Ohwoka, A. O. Polyurethane Sealing Disc on CleaningPigs; Chracterization and Dynmic Behavior. R. J. R. C. Wax Deposition in Crude Oil Pipes. a. Cost Effective Cleaning pigs Enabling High Frequency Pipeline Inspection. Kuala Lampur: Offshore Technology Conference Asia 1-10 Smith, C. and J. R. Y. L. a. K. S. Analyzing the Crash between Gauging Pig and the Elbows of U-Shaped Pipeline 9th International Pipeline Conference, American Society of Mechanical Engineers, 453-457. APPENDICES 8. 1 List of Figures Fig. 1: Clogging of the pipe caused by wax deposition and accumulation of debris on the inner walls of the pipe Fig. 2: Multi-technology tool Fig. 18t ± 0. 18t ± 0. 25t ± 0. 25t ± 0. 25t Width sizing accuracy at 80% certainty (mm) ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm Length sizing accuracy at 80% (mm) ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm ± 20 mm Table 1 Anomaly detecting and sizing specifications of 6 inches and 8 inches tool Milestone Possible Flaws Steel Production Impurities, cavities, segregation etc.