| A-K pipeline is located in the South TLG basin in Kazakhstan and delivers the treated crude oil from the ALS oil field to the KMKL heating pump station.As the throughout of crude oil in the ALS oil field is reduced,the throughout of the pipeline is much smaller than that of the design.At present,normal and opposite direction transportation is adopted.It often occurs that the throughout of initial station increases while the pressure decreases.In order to ensure the safe and smooth operation of the pipeline,it is necessary to study the current situation of the pipeline transportation,analyze the reasons for the difficulties,determine the economic and reasonable technological reconstruction plan.The unified wax deposition model of waxy crude oil pipeline was adopted,and the current waxing condition of the pipeline was simulated according to the pipeline operating parameters.The throughout,temperature and pressure of the pipeline was researched.The causes of the current delivery difficulties was analyzed.Results showed that serious wax deposition in the pipeline were the cause of difficulties in transportation.Some measures such as improving the oil temperature at the initial station,adding insulation layer,adding intermediate heating station were put forward.Wax deposition and pipeline operation were researched under such measures.Results showed that added heating station at 37.5km could solve the problem.Considering the pipeline should run continuously,add wax-proofing agent was also put forward.Alternative wax-proofing agent includes CN1-6H、SHX-2/3、KD-1,and the main indicators of the experiment include viscosity reduction rate,condensation point depression and stability,wax-dissolving capacity,wax inhibiting rate and wax adhesion.Results showed that adding 50 ppm KD-1 is the best choice.The process reconstruction should be carried out in two phases.Adding 50 ppm KD-1 is the first phase,then the output could reduce to 64 t/h and run 40-45 h after stop40 h in the summer.Adding heating station at 37.5km is the second phase,the outlet temperature is 60 ℃ and the output could reduce to 64 t/h in the summer. |
