3C - Crude Oil Pipeline Systems & Pipeline Configurations

changes in temperature affect liquid density and viscosity and affect pressure profile if liquid transported near ambient conditions--> isothermal assumption in calculations liquids in pipeline classified according to temperature behaviour into light, intermediate and heavy HCs light and heavy dealt with non isothermally intermediate HCs not as sensitive to changes in temperature in terms of density and viscosity frictional heating negligibly small isothermal flow assumption is reasonable if adequate average temperature is calculated design considerations should include vapour pressure because that depends on temperature pipeline network composed of: injection points - delivery point- intermediate station - pump stations - block valve stations - regulating stations injection points: products injected into line delivery point: where product will be delivered to consumer or another pipeline intermediate stations: provide side stream injections or delivery points pump stations: located along line to move liquid through pipeline block valve stations: first line of mitigation for pipelines. enables operator to isolate segments of line regulating stations: special type of valve station where either pressure or flow is controlled pressure regulators usually located downhill of a peak flow regulators installed at delivery stations Pipeline configurations: 1. side stream delivery 2. side stream injection 3. pipelines in series 4. pipelines in parallel modes of side stream delivery : strip delivery - full stream delivery through branch line - full stream delivery through mainline design considerations for side stream delivery: 1. satisfy delivery pressure requirements at both delivery locations while maintaining high P at take off point 2. using a smaller diameter downstream if delivery volume is large ( increase in Q) 3. installing an extra facility such as pump to satisfy branch line delivery requirement 4. select pumps to meet max and min flow requirements Side stream injection: liquid may be injected from branch lines into the main pipeline Q is lower upstream from injection, so pressure drop upstream is lower than downstream block valve installed upstream and closed in full stream injection or batching injection pressure on the branch line should be higher than main line pressure to prevent back flow larger diameter used downstream to handle large volumes from injection pumps upstream to injection should be designed to accommodate reduced flow rate. flow rate downstream of injection will be high so flow rate needs to be reduced upstream viscosity of injection fluid is high, high pressure drop, pumps downstream need to be designed accordingly pipelines in series when different flow rates are transported or different pressures are required in series--> same flow rate but different velocities different sizes connected in series for change in flow or change in elevation larger diameter --> slower velocity-->smaller friction factor--> lower pressure loss different pipe wall thickness in series to reduce pipe material and cost while maintaining safety thinner wall--> suction side thicker wall--> discharge side pipelines in parallel: arranged in parallel to reduce excessive pressure drop in a certain sections of the pipeline and increase throughput in bottleneck pressure remains the same in parallel, but Q is the sum of flow rates in size of parallel pipelines can be different and so will the velocity be equations governing flow in parallel pipes slide 24