Pipeline Pressure Drop Research Articles

Application of compound viscosity reducer for low temperature transportation in Huabei oilfield

Reducing the viscosity of heavy oil is one of the main works in oilfield development. This article chose the nonionic surfactant and anionic surfactant as the main agent, and after optimizing the proportion of combination and joining the functional additive, the compound viscosity reducer with dual function of viscosity reduction and pour point depression for low temperature transportation in pipelines is prepared. The compound viscosity reducer is non-toxic, safe and environmentally. Experiments show that when the concentration of the compound viscosity reducer is 0.05%, the freezing point of crude oil fall by more than 8 °C, and the viscosity reduction rate is more than 75%. After field application in Huabei oilfield, the average pipeline pressure drop is 0.6-1.5 MPa( the average pressure drop rate is 53%), which plays the important role for low temperature transportation in pipelines

Optimization of Gas Pressure Modes in Gas Supply Systems

At present, general gasification on the basis of the natural gas is carried out without proper grounds for all the criteria affecting the efficiency of these systems. At the same time, the expediency of the natural gas provision must be carried out taking into account configuration of the networks in the settlement, density of the population in the gas-supply territory, type of the gas-using equipment installed at the consumer and other determining factors. The absence of these criteria often leads to huge unreasonable investments in the gas distribution systems, which sharply reduces their efficiency and effectiveness. The existing practice of operating gas distribution pipelines causes a low magnitude of the calculated pressure drop and, consequently, an increased material consumption of the gas networks. The introduction of the gas supply systems with house pressure stabilizers into design practice requires the development of scientifically based methods for their calculation and design. One of the most important prerequisites for the calculation of the gas distribution systems is the substantiation and optimization of the calculated pressure drop in the distribution gas pipelines. The purpose of this study: development of an optimal structure for the distribution of the natural gas, depending on the individual features of the gas fuel consumption.

CO2 Pipeline Design: A Review

There is a need to accurately design pipelines to meet the expected increase in the construction of carbon dioxide (CO2) pipelines after the signing of the Paris Climate Agreement. CO2 pipelines are usually designed with the assumption of a pure CO2 fluid, even though it usually contains impurities, which affect the critical pressure, critical temperature, phase behaviour, and pressure and temperature changes in the pipeline. The design of CO2 pipelines and the calculation of process parameters and fluid properties is not quite accurate with the assumption of pure CO2 fluids. This paper reviews the design of rich CO2 pipelines including pipeline route selection, length and right of way, fluid flow rates and velocities, need for single point-to-point or trunk pipelines, pipeline operating pressures and temperatures, pipeline wall thickness, fluid stream composition, fluid phases, and pipeline diameter and pressure drop calculations. The performance of a hypothetical pipeline was simulated using gPROMS (ver. 4.2.0) and Aspen HYSYS (ver.10.1) and the results of both software were compared to validate equations. Pressure loss due to fluid acceleration was ignored in the development of the diameter/pressure drop equations. Work is ongoing to incorporate fluid acceleration effect and the effects of impurities to improve the current models.

Rheological study of two- and three-phase highly viscous fluid flow in pipelines

The study of highly viscous multiphase flow systems is of fundamental interest in the oil industry. Most of the Venezuelan oil fields produce heavy oil with other production fluids, such as water and gas, and sand particles flowing from the reservoir to the surface facilities. A fraction of these phases flows fully separated, while another one flows as a dispersed system composed by water/oil emulsion with gas bubbles dispersed as a foamed emulsion. With the objective to understand and characterize this latter complex system, new experiments have been performed in 0.0243-m and 0.0508-m horizontal pipelines, for air/highly-viscous oil of 0.430 Pa s at 20 °C, and water/air/oil mixture with a water-in-oil emulsion of 0.560 Pa s at 20 °C. The three-phase flow pressure gradient was found to be approximately 15% higher than for the two-phase system, at similar gas and liquid superficial velocities. The air/oil and air/oil/water foamed emulsion behaved as non-Newtonian fluids, when these are considered as pseudo-homogeneous systems.A model to predict the flow pattern and pressure drop in horizontal pipelines was developed with an extensive database of 2167 experimental points, including new data and information collected and processed from different sources. A performance factor of 0.41 for Brito's three-phase (TM) model was consistently better than the performance factor obtained for other models commonly used by the oil and gas industry in similar multiphase flow systems.

Experimental values for adjusting an automatic control valve in gas pipeline transportation

When a natural gas pipeline ruptures, the adjacent automatic line control valves (ALCVs) should close quickly to prevent leakage or explosion. The differential pressure set point (DPS) at each valve location is the main criteria for value setting in ALCV action. If the DPS is not properly adjusted, the ALCV may mistakenly close or it may not take any action at proper time. This study focused on the DPS values prediction for setting ALCV installed on a gas pipeline with 1mm orifice diameter. The effect of characteristic parameters such as pipeline operational pressure (POP) and pipeline pressure drop rate (ROD) due to rupture or major leak was experimentally investigated on DPS. Twenty-five different conditions with double set of typical mentioned characteristic parameters were chosen. For each condition, the differential pressure (DP) was measured over 180 seconds by analyzing the experimental values. Therefore, 25 maximum DP values (DPSs) were obtained. The DPS increases by increase in ROD or decreasing POP parameters. Because of using nitrogen gas instead of natural gas due to safety reasons, the DPS results can be practically applied by adding a safety factor of 15%. The diagram of DPS with respect to ROD and non-dimensional DPS (DOP) versus non-dimensional ROD (RTP) was provided for different POPs.

Hydrate agglomeration modeling and pipeline hydrate slurry flow behavior simulation

Abstract Dynamic modeling and numerical simulation of hydrate slurry flow behavior are of great importance to offshore hydrate management. For this purpose, a dynamic model of hydrate agglomeration was proposed in this paper. Based on population balance equation, the frame of the dynamic model was established first, which took both hydrate agglomeration and hydrate breakage into consideration. Then, the calculating methods of four key parameters involved in the dynamic model were given according to hydrate agglomeration dynamics. The four key parameters are collision frequency, agglomeration efficiency, breakage frequency and the size distribution of sub particles resulting from particle breakage. After the whole dynamic model was built, it was combined with several traditional solid–liquid flow models and then together solved by the CFD software FLUENT 14.5. Finally, using this method, the influences of flow rate and hydrate volume fraction on hydrate particle size distribution, hydrate volume concentration distribution and pipeline pressure drop were simulated and analyzed.

Effect of heavy molecular weight polymer on quality of drinking water

The transport of fluids in pipes results in huge energy losses due to pressure drop. In addition, it has been established that the use of minute quantities of heavy molecular weight polymers leads to substantial reduction in the occurring frictional pressure drop in pipelines. Up to 80% reduction in pressure drop for water flows have been reported. These materials have been known to insignificantly affect the physicochemical and rheological properties of their host solvents. However, the use of drag reducing polymer and its effect on the quality of drinking water has not been well reported. In this work, the detailed study of the effect of addition varying concentrations of a drag reducing polymer (DRP) (Magnafloc 1011; hydrolysed copolymer of polyacrylamide and sodium acrylate, Mol. Wt.: 10 × 106 g/mol.) in treated water samples was carried out. The physicochemical parameters such as pH, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, total dissolved solid, total hardness, alkalinity, electrical conductivity, temperature and turbidity were determined after injecting concentrations of 5 ppm, 10 ppm, 20 ppm and 50 ppm of the DRP. The samples with the polymer was left over ten days while the parameters were measured at intervals. The results were compared with the World Health Organisation water quality standards in order to note the deviations and carefully consider the health effects on the consumers at large. The results showed that the DRP could also serve as a coagulating agent for water treatment. It was observed that the tested parameters were within the limit of the water quality standards for all the days investigated. The result also showed an optimum concentration of 10 ppm of the DRP and that the water is safe for drinking even after 10 days. The result is promising and thus encouraging the use of this technology in transporting our drinking water with the attendant reduction in operational cost.

The Effect of Permeability on Lignite Fly Ash Pneumatic Conveying System Design

The aim of this experimental study was to evaluate the effect of permeability on the mode of flow that lignite fly ash will support in a pneumatic conveying pipeline. This research was initiated by recurring problems with the long distance and high capacity low grade lignite ash pneumatic conveying system at the 1200 MWe thermal power plant, such as clogging, unsteady flow mode, significant increase of velocity due to pressure drop and erosive wear of pipeline. Ash samples were taken during pneumatic conveying system clogging for further analysis. The experiment was limited to measuring parameters that provide data to determine minimum fluidizing velocity and permeability. The results showed very heterogeneous materials of group B by Geldart, what caused specific phenomenon during the experimental fluidization tests. Minimum fluidizing velocity for this kind of material is not authoritative for defining pneumatic conveying system, since extremely heterogeneous materials at this air speed will remain stationary or will convey very slow or with stoppage, and that required velocities are from 10 to 15 times higher than minimum fluidizing velocity. According to the results, this ash is the most suitable for dense phase pneumatic conveying.

An experimental study of the effective parameters on automatic line-break control valves action in natural gas pipelines

The automatic line-break control valve (LBV) is a robust self-contained pipeline monitoring system which is widely used to prevent gas releasing upon rupture or large leakage event in the oil and gas pipelines. The differential pressure set point (DPS) at each valve location is the main criteria for value setting in LBV action. If the DPS is not properly adjusted, the LBV may mistakenly close or it may not take any action at proper time. In this study, the effect of characteristic parameters such as orifice diameter (OD), pipeline operational pressure (POP) and pipeline pressure drop rate (ROD) due to rupture or major leak was experimentally investigated on DPS. 100 different conditions with triple set of typical mentioned characteristic parameters were chosen. For each condition, the differential pressure (DP) was measured over 180 s by statistically analyzing the experimental results. Therefore, 100 maximum DP values (DPSs) were obtained. The attainable time to DPS depends only on OD and is independent of the POP and ROD and decreases by increasing the OD. The DPS increases by increase in ROD or decreasing OD or POP parameters. Because of using nitrogen gas instead of natural gas due to safety reasons and the uncertainties, the DPS results can be practically applied by adding a safety factor of 10%–15%. Finally, the diagram of DPS with respect to ROD was provided for different POPs and ODs. The diagram can be used as a basis for designing and regulating of LBVs installed on gas transportation pipelines.

Acceleration pressure drop analysis in horizontal dilute phase pneumatic conveying system

In pneumatic conveying pipelines, there are specific periods and distances where particles start to accelerate or deaccelerate from specific velocity to steady state. This phenomenon attributes an additional loss of energy also invoke as acceleration pressure drop. The total acceleration pressure drop is defined by measuring the pressure difference between two points at the acceleration zone. The pressure drop of steady state flow for the same length is then reduced from the previous measurement to find acceleration only energy loss. Theoretical equation of momentum change, a material physics, has used to explain the acceleration pressure drop in horizontal pipe. Experimental results have compared with the values of theoretical equation. Results indicated that predicted pressure drop is deviating from the experimental results. Hence, the problem was realized that there was need to precisely predict steady state (collision and friction) pressure drop in this zone, which in classical way of prediction would be used to do just by extrapolation up to the acceleration zone. Hence, a novel factor α has derived by the authors to accurately predict steady state loss in this zone. Experiments have conducted by using different kinds of materials (Bottom ash, Glass beads, Semolina etc.) at different conveying conditions. To view point of design engineers, contribution of acceleration pressure drop in total pipeline has demonstrated by comparing 10m and 100m long horizontal pipe. To a simplest case of conveying criteria, acceleration loss contribute 25% of total pipeline pressure drop for 10m pipe and it reduced to 4% for 100m pipeline.It has concluded that acceleration pressure drop, between any two velocities, would be predicted with momentum change equation and there is need to accurately predict the steady state pressure drop by factor alpha (α) to predict total pressure drop in acceleration zone.

Obstacle contained system (OCS) design method and its application in valve core orifice design of pilot-control globe valve

With the development of the society and the times, traditional parametric design methods are witnessing a severe challenge due to the more and more complex physical systems. Thus, developing novel parametric analysis methods is very important for dealing with complex physical systems, refining useful parameters from numerous data, and proposing accurate prediction formulas. A spring slider system, a direct-current circuit system, a pipeline pressure drop system and a steady heat transfer model of flat plate system were described from the point of systemic parametric analysis method. Then, the key physical parameters in above four systems were summarized. Based on the comparative results, a novel systemic parametric design method, obstacle contained system (OCS) design method, was proposed. The OCS was made up of three elements:an obstacle element, a pass body element and a D-value element. With an abundant accurate data pole, the OCS design method could build the direct relationship of the obstacle element and the D-value element, which meant the simplification of the physical models and much easier to get relatively accurate results. Meanwhile, the design of pilot-control globe valve orifice was checked with both the OCS design method and the numerical simulation. The diameter of orifice on the valve core could influence the pressure difference and the maximum vapor rate inside pilot-control globe valves. Achieved by two different methods, the OCS design method and the numerical simulation, the results showed that the effects of orifice diameters on the pressure difference and the maximum vapor rate under different inlet velocities, were within 2% errors, which was reasonable and acceptable for the engineering application. In other words, the OCS design method was credible for parametric analysis. In future, the OCS design method has a broad application prospect to analyze various types of physical models especially in the era of big data.

Design optimization of oilfield subsea infrastructures with manifold placement and pipeline layout

This paper presents a practical and effective optimization method to design subsea production networks, which accounts for the number of manifolds and platforms, their location, well assignment to these gathering systems, and pipeline diameter. It brings a fast solution that can be easily implemented as a tool for layout design optimization and simulation-based analysis. The proposed model comprises reservoir dynamics and multiphase flow, relying on multidimensional piecewise linearization to formulate the layout design problem as a MILP. Besides design validation, reservoir simulation serves the purpose of defining boundaries for optimization variables and parameters that characterize pressure decrease, reservoir dynamics and well production over time. Pressure drop in pipelines are modeled by piecewise-linear functions that approximate multiphase flow simulators. The resulting optimization model and approximation methodology were applied to a real oilfield with the aim of assessing their effectiveness.

Computational analysis on disposal of coal slurry at high solid concentrations through slurry pipeline

ABSTRACTThe present study is conducted to investigate the flow characteristics of coal–water slurry having high solid concentrations in slurry pipeline using commercial computational fluid dynamics. An Euler–Lagrange multiphase approach is used to simulate the flow of coal–water slurry in 50, 100, and 150 mm diameter straight pipelines. The simulations are carried out using various turbulence models and the results obtained are compared with the experimental results presented in the literature. It is found that the shear stress transport (SST) k–ω turbulence model shows good agreement in comparison to other turbulence models. The SST k–ω turbulent scheme is used to solve the governing equations of two-phase model. Simulations are carried out for coal slurry velocity range 2–5 m/s. Numerical simulation results show that the pressure drop in pipeline increases non-linearly with increase in velocity, solid concentration, and particle size. Extensive simulation is also carried out to estimate the effect of pipe diameter on the pressure drop characteristics through pipeline. It is observed that the pressure drop decreases with the increase in pipe diameter. It is found that the particle sizes have significant influence on pressure drop, solid concentrations, and velocity distributions during the flow of coal–water slurry in a pipeline.

Modelling of two phase solid-liquid flow in horizontal pipe using computational fluid dynamics technique

In this paper three-dimensional fluid flow characteristics of slurry pipeline has been studied using commercial Computational Fluid Dynamics (CFD) code FLUENT at different velocities and solid concentrations. An Euler-Lagrange multiphase approach was used to simulate the flow of bottom ash slurry in a 50 mm diameter straight pipeline. Simulations were carried out with bottom ash at velocity range of 1–3 ms–1. The solid concentration of bottom ash particles was varied from 40 to 60% (by weight). The simulations were carried out using SST k-ω turbulence model and the results obtained were compared with experimental results. It was found that the SST k-ω turbulence model shows good agreement with experimental data. Numerical simulation results show that the pressure drop in pipeline increases non-linearly with increase in velocity and solid concentration.

The effect of a TEG additive on hydrate formation

ABSTRACTIn gas industry, gas hydrate formation has both advantages and disadvantages. The best advantage of gas hydrate is Persian Gulf water sweetening, carbon dioxide capture, and gas storage, and its drawbacks are pressure drop, plugging, and explosion in pipelines. In recent years, using the inhibitors to prevent hydrate formation is being considered among researchers. In this study, the new equilibrium data for hydrate formation of inlet natural gas to Gachsaran NGL-1200 refinery with addition of Tri ethylene glycol (TEG) with mass concentration of 5% and 15% in distilled and Persian Gulf waters were measured by constant-volume method. The experimental results show that the hydrate formation conditions will be hard with the increase of TEG concentration in distillated and Persian Gulf waters. In other words, TEG addition to Persian Gulf water had more inhibitory effect in hydrate formation than TEG addition to distilled water. The hydrate formation temperature, in pressure range of 28–29 bars, reduced 0.3°C and 2.7°C for distilled water and 2.8°C and 4.6°C for Persian Gulf water in presence of TEG with mass concentration of 5% and 15%, respectively.

Pressure drop in pipelines due to pump trip event

We consider the pressure pulse or surge in a pipeline due to an unplanned sudden shutdown of a pump system in the pipeline network. This is known as water hammer. Our primary focus is the negative pressure pulse that travels downstream from the pump(s), is reflected with a sign reversal from the end, and travels back to the pump(s). As part of the preliminary design of a pipeline it is necessary to determine the minimum head envelope associated with such an event, which is used to determine where surge protection will be needed in the pipeline. Of particular interest is whether the initial head drop at the pump(s) due to a sudden drop of the flow speed to zero, as given by the Joukowski formula, gives a sufficiently accurate prediction of the minimum head at the pump(s). This minimum head is used to construct the minimum head envelope for the downstream pipeline. An examination of the relevant literature along with solution of the water hammer equations shows that, assuming the flow speed falls instantaneously to zero at the pump(s), the total drop in head at the pump(s) is given by the sum of the initial Joukowski head change and the friction loss under normal operating conditions. While the friction loss may not be significant in short pipelines, in long pipelines it cannot be neglected.

On developing improved modelling and scale-up procedures for pneumatic conveying of fine powders

Pneumatic transport of fine powders in fluidized dense-phase mode is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, because of the reasons of reduced gas flow rate and power consumption, decreased conveying velocities, improved product quality control, reduced pipeline sizing and wear rate, increased workplace safety etc. For the reliable design of a pneumatic conveying system, it is important to accurately predict the total pipeline pressure drop. However, accurate prediction of pressure drop from an improved understanding of the fundamental transport mechanism of fluidized dense-phase flow condition has only made limited progress till now because of the highly concentrated and turbulent nature of the gas-solids mixture. Power plant fly ash (median particle diameter: 30μm; particle density: 2300kg/m3; loose-poured bulk density: 700kg/m3) was conveyed through different pipelines (69mm I.D.×168m long; 105mm I.D.×168m long; 69mm I.D.×554m long). 8 different fly ash samples were tested in a fluidizing column for their deaeration characteristics and fluidized bulk densities were determined. Governing equations of flow for the dense-phase pneumatic conveying system of fine powders were solved using Runge-Kutta-Fehlberg (RKF45) method for different fluidized bulk densities of fly ash and air flow rates. The results have shown that the particle and actual gas velocities and the ratio of the two velocities increase in the direction of flow, while a reverse trend was apparent for the solids volumetric concentration. The results were compared against the predictions obtained using existing empirical relations for particle velocity. To develop an improved model for solids friction factor, an existing reliable pure dilute-phase model has been modified for dense-phase flow condition by incorporating sub-models for particle to actual gas velocity and impact and solids friction factor. The developed solids friction factor model was validated by using it to predict the total pipeline pressure drops for larger and longer pipelines and by comparing the experimental and predicted pneumatic conveying characteristics. The results have shown improved reliable predictions and that the model is capable of addressing the gradual transition of flow mechanism from dense- to dilute-phase. The accuracy of prediction is similar (in fact better in certain scale-up cases) when compared to a recently developed two-layer based model (developed by some of the authors). The results demonstrate the importance of incorporating particle and actual gas velocity terms in the model of solids friction factor instead of the prevailing techniques that overly depend on using superficial gas velocities.

The effect of micro/nano-particles on pressure drop in Oil pipeline: Simulation

A high pressure drop happens when heavy oil with high viscosity moves through the oil pipeline. A variety of methods to avoid this pressure drop is available. One of which is injection of chemicals to reduce the viscosity and ultimately reduce pressure drop. Using the pipesim software, the effect of dispersion of nano and micro-particles into the oil has been simulated to study the amount of the pressure drop pipe lines. The effects of the parameters such as the type and concentration of particles, temperature, oil rate, inside diameter of pipe and the flow type were examined. Simulating the experimental data by the software, gives promising experimental results. The results show that the copper micro-particles with 0.1 wt% concentration have the lowest pressure drop per unit length. At low temperatures the effect of concentration of micro particle is important and at high temperatures effects of temperature is dominant. It is noteworthy that in higher rates, the presence of any amount of particles has a favorable impact on the pressure drop. For laminar and turbulent flow, pressure drop will decrease when the oil viscosity decreases. On the contrary for transient flow, pressure drop will increase when the viscosity reduces.

Synthesis of heat exchanger network considering pressure drop and layout of equipment exchanging heat

The present work is related to development of a MINLP (Mixed integer non linear programming) model for the synthesis of HEN (heat exchanger network) considering pressure drop through connecting pipelines, heat exchangers and the layout of the equipment exchanging heat simultaneously. The pressure drop of shell and tube sides in a heat exchanger is considered in the model. Further, detailed plant layout is considered for accounting pressure drop in pipe line as well as piping cost. The objective function of the MINLP model is the TAC (total annual cost), which considers utility cost, capital investment cost of exchangers, pipe investment cost and pumping cost due to pressure drops in exchanger as well as in pipe length. The developed model is illustrated using a case study. The results show that the TAC of HEN is reduced by 27.4% than that obtained for the topology without considering pressure drop in exchanger. However, placement of exchangers in the layout contributes to 4.5% in TAC. Results found through the present model are compared with that of published models.

Modeling solids friction factor for fluidized dense-phase pneumatic transport of powders using two layer flow theory

Fluidized dense-phase pneumatic conveying of powders is becoming increasingly popular in various industries, such as power, chemical, cement, refinery, alumina, pharmaceutical, limestone, to list a few, due to the reasons of reduced gas flows and power consumption, improved product quality control, reduced pipeline sizing and wear rate, increased workplace safety etc. An accurate estimation of total pipeline pressure drop is of paramount importance for the reliable design of a pneumatic conveying system. However, because of the highly concentrated and turbulent nature of the gas–solids mixture, fundamentally understanding the flow mechanism and accurately predicting the pressure drop as an important design parameter has only made limited progress so far. This paper results from an ongoing investigation into developing a validated modeling procedure for solids friction factor for the accurate prediction of pressure drop and optimal operating conditions for fluidized dense-phase pneumatic conveying systems. Under the present study, a two-layer based model has been developed by separately considering the solids friction contributions of the non-suspension (dense) bed of powders flowing along the bottom of pipe and the suspension (dilute-phase flow) of particles occurring on top of the non-suspension layer. Volumetric loading ratio and dimensionless velocity have been used to model the non-suspension dune flow layer. A solids impact and friction term and dimensionless velocity have been employed to model the dilute-phase flow due their established reliability. Models have been developed using the straight-pipe conveying data of two types of fly ash, cement and ESP dust (median particle diameter: 7 to 30μm; particle density: 2300 to 3637kg/m3; loose-poured bulk density: 610–1080kg/m3). The developed models for solids friction were validated for their scale-up accuracy by using them to predict the pressure drops in five larger and longer pipelines (69mm I.D.×168m long; 105mm I.D.×168m long; 69mm I.D.×554m long, 65mm I.D.×254m long and 80/100mm I.D.×407m long pipes) and by comparing the experimental versus predicted pneumatic conveying characteristics. The two-layer model provided improved accuracy compared to existing models indicating that the model is able to adequately address the dense- to dilute-phase transition criteria.