At present, most of the domestic high-viscosity crude oil lines are centrifugal pumps, heavy oil pumps, twin screw pumps, gear pumps and the like. Centrifugal pump low efficiency, high energy consumption, high cost of oil (at present, the efficiency of centrifugal pumps conveying heavy oil is very low, up to about 40%), the world's most advanced centrifugal pump efficiency is only about 80% (water efficiency) , While delivering high viscous oil products, the efficiency is only 40% ~ 50%; rotor heavy oil pump, twin screw pump, gear pump in the delivery of heavy oil-rich high efficiency, but there is not wear and run unreliable , The problem of large maintenance workload. This is a big challenge for our heavy sand transportation. Therefore, it is the most effective and direct way to reduce costs when using a single screw pump to deliver high viscosity sandy crude oil. Single-screw pump principle Single-screw pump is a reliable and simple structure of the eccentric rotor-type empty pump. The main pump parts by a certain shape of the surface of the rotor (screw) and the corresponding inner surface of the stator composition. The rotor is a screw with a large lead, a large tooth height and a small internal thread diameter. The stator is a flexible bushing with a double helix. Since the stator lead is twice the pitch of the rotor, the rotor engages in the stator to form a special contact line (seal line) which divides the stator cavity into mutually non-communicating, 180 ° phase angle sealed cavities. When the rotor rotates in the stator, the sealed chamber moves in the axial direction from the suction end of the pump to the discharge portion, and the medium is continuously delivered from the suction end to the discharge end in the cavity. As the stator is made of rubber with good elasticity, when the medium contains solid particles, if the solid particles are squeezed in the sealing line, the surface of the stator rubber will be compressed due to the elastic effect of the rubber stator, the solid particles will cross the sealing line, the stator rubber rebound Restore the original shape The single-screw pump can therefore deliver media containing solid particles. Features of NEMO (r) Pumps Nachi's NEMO (r) pump rotors are manufactured from common and special materials and are resistant to wear and corrosion. After hardening the surface of the rotor is more suitable for the transport of oil-bearing sandy media. Cylinder pin type, toothed and other structures of universal joint drive shaft design, high strength, long life, good transmission stability. Stator selection of different formulations of rubber to meet the oil, wear, high temperature and other needs of different working conditions. 1, suitable for corrosive media, gas-bearing media, sediment-containing solid particulate media and high-viscosity media delivery. Gas content of up to 75%, medium viscosity up to 50000mPa.S, with a solid content of up to 60%, allowing the solid particle diameter ≤ 3.5 ~ 32mm, allowing the fiber length ≤ 37 ~ 272mm. In the case of a reasonable pipeline configuration, the oil and gas medium can be reduced heating or non-heating transport, thereby enhancing economic efficiency. 2, self-priming ability, suction up to a high of 8.5m. Start without the need for irrigation water, it can easily convey the oil and sewage in the ground pool. 3, the volume of the liquid flow does not change when the pump, there is no turbulence, stirring and pulsation. Low pump speed, small vibration, low noise, stable and reliable operation. Long stator and rotor life. 4, the flow and speed is proportional to the pressure in the low-speed low-flow to maintain a stable, with good regulatory performance, easy to achieve automation and control. 5, high system efficiency, up to 82%, no need to export control valves, reducing the pipeline resistance and improve economic efficiency. 6, reliable operation, simple structure, easy maintenance. Single-screw pump delivery process Single-screw pump as a positive displacement pump, so in the delivery of crude oil, the flow design has special requirements. When the outlet pipe is clogged or operated improperly, the pump will be over-pressured and the parts may be easily damaged. Therefore, a safety valve must be installed between the discharge pipe of the pump and the suction pipe or a pressure switch should be installed on the outlet pipe. In the absence of liquid or imported pipeline blockage, will cause the pump to dry run, causing the stator due to friction temperature, rubber aging, or even burn out. Therefore, the inlet pipe to install pressure switch or temperature control switch on the stator. In order to prevent the outlet pipe when stopping the pump liquid backflow, the design process, the outlet pipe should be installed on the check valve. Conclusion The NEMO (r) pump's characteristics determine its performance in heavy oil-bearing sediments. The field application shows that the pumps have high efficiency, small vibration, low noise, stable and reliable operation, convenient maintenance and long service life, and overcome various problems existing in other types of pumps when transporting heavy oil with sediment. Very suitable for spreading and conveying in sand
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