Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be ...Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be transported through pipelines from the point of production to storage facilities orrefineries. The transportation of heavy crude oil by pipeline poses serious problems related to the highviscosity and flow difficulties, particularly in cold climates or offshore conditions. Indeed, the viscosity ofcrude oil is an important physical property that influences and controls crude oil flow in pipelines.Viscosity introduces resistance to movement by causing a shear or frictional force between the fluidparticles and the boundary walls. This high viscosity means that the pumping power requirements forcrude oil in a long-distance pipeline are very high in order to overcome the increasing shear and frictionforces. Therefore, in order to facilitate the pumping of these viscous oils and reduce operating expensesand the negative impact of pressure drops in pipelines during flow and processing, their viscosity mustbe reduced. Various techniques are used to increase pumping efficiency and improve the flow of crude oilthrough the pipeline, which may present logistical, technical or economic disadvantages for a givenapplication. The main ones are the addition of surfactants or polymers, dilution with lighter crudes, useof water as annular fluid, thermal remediation and emulsification with surfactant (O/W). This reviewhighlights the methods currently used to enhance the fluidity of heavy crude oil in pipelines behindrheology improvement, in particular the addition of additives and the use of water and surfactants tocreate a stable emulsion of heavy crude oil in water have been considered.展开更多
The consumption and demand for petroleum are increasing dramatically with the rapid development of industry and energy sector.As a result,petroleum refineries produce the greatest amount of oily sludge formed at the b...The consumption and demand for petroleum are increasing dramatically with the rapid development of industry and energy sector.As a result,petroleum refineries produce the greatest amount of oily sludge formed at the bottom of storage tanks during oil storage operations,which has a severely negative impact on the storage capacity and the operational safety of the storage tank.The present study focuses on the rheology of this complex fluid from Algerian crude oil storage tanks.Rheological measurements were performed at different temperatures under steady shear and dynamic oscillometry using AR-2000 Rheometer.The results obtained show that the sludge exhibits yield-pseudoplastic flow behavior at low shear rates,which is adequately described by the Herschel Bulkley model based on the standard error and correlation coefficient values.However,quasi-Newtonian flow behavior occurs at very high shear rates.The increase in temperature had positive effects on the rheological properties of the sludge,including dynamic viscosity,shear stress,yield stress,complex modulus,elastic modulus and viscous modulus.The dynamic rheology studies have shown that the sludge material behaves more like a solid than a liquid under all experimental conditions studied.展开更多
文摘Given the combination of rising global energy demand and the decline in conventional crudes, heavycrudes are generally considered to be the future energy resource. In many regions of the world, heavycrude oil must be transported through pipelines from the point of production to storage facilities orrefineries. The transportation of heavy crude oil by pipeline poses serious problems related to the highviscosity and flow difficulties, particularly in cold climates or offshore conditions. Indeed, the viscosity ofcrude oil is an important physical property that influences and controls crude oil flow in pipelines.Viscosity introduces resistance to movement by causing a shear or frictional force between the fluidparticles and the boundary walls. This high viscosity means that the pumping power requirements forcrude oil in a long-distance pipeline are very high in order to overcome the increasing shear and frictionforces. Therefore, in order to facilitate the pumping of these viscous oils and reduce operating expensesand the negative impact of pressure drops in pipelines during flow and processing, their viscosity mustbe reduced. Various techniques are used to increase pumping efficiency and improve the flow of crude oilthrough the pipeline, which may present logistical, technical or economic disadvantages for a givenapplication. The main ones are the addition of surfactants or polymers, dilution with lighter crudes, useof water as annular fluid, thermal remediation and emulsification with surfactant (O/W). This reviewhighlights the methods currently used to enhance the fluidity of heavy crude oil in pipelines behindrheology improvement, in particular the addition of additives and the use of water and surfactants tocreate a stable emulsion of heavy crude oil in water have been considered.
文摘The consumption and demand for petroleum are increasing dramatically with the rapid development of industry and energy sector.As a result,petroleum refineries produce the greatest amount of oily sludge formed at the bottom of storage tanks during oil storage operations,which has a severely negative impact on the storage capacity and the operational safety of the storage tank.The present study focuses on the rheology of this complex fluid from Algerian crude oil storage tanks.Rheological measurements were performed at different temperatures under steady shear and dynamic oscillometry using AR-2000 Rheometer.The results obtained show that the sludge exhibits yield-pseudoplastic flow behavior at low shear rates,which is adequately described by the Herschel Bulkley model based on the standard error and correlation coefficient values.However,quasi-Newtonian flow behavior occurs at very high shear rates.The increase in temperature had positive effects on the rheological properties of the sludge,including dynamic viscosity,shear stress,yield stress,complex modulus,elastic modulus and viscous modulus.The dynamic rheology studies have shown that the sludge material behaves more like a solid than a liquid under all experimental conditions studied.
