Increasing the pump energy efficiency of the system for discharging liquefied natural gas from large-capacity storage facilities via design improvement

Objective. To determine the most relevant way to improve the energy efficiency of the system for discharging liquefied natural gas (LNG) from large-capacity storage facilities. Methods. The method of analysis of existing systems for LNG discharge from storage tanks was used to identify critical (emergency) elements of the system to be improved and possible options of improving structural elements. Results. The operation of the system for discharging LNG from storage tanks was analysed and its main characteristics were described. Main problems associated with designing and building borehole pumps, as well as goals and tasks of designing new borehole pump structures were studied. The main types of LNG borehole pumps, their varieties, and types of drives were studied to choose the most optimal new option of improving pumps for systems for discharging LNG from storage tanks. Further, it will be necessary to calculate geometric parameters of the hydroturbine and operation modes of its wheel being in connection with the centrifugal pump wheel. Conclusion. Experience of using storage facilities shows that LNG pumps are the most critical units significantly increasing production risks. Therefore, the LNG borehole pump design improvement was chosen as a method to increase the energy efficiency of the system for discharging LNG from large-capacity storage facilities. Based on the considered advantages and disadvantages of structural elements of the existing LNG borehole pump design, we chose the replacement of the electric pump drive with an alternative one as the most optimal improvement method.

PROTECTION OF CENTRIFUGAL PUMPS FROM ABRASIVE WEAR USING A VACUUM HYDROCYCLONE

The design features of the existing design and technology for the protection of downhole pumps of the ECV type from abrasive wear during operation are considered and analyzed. Based on the analysis, a new method for capturing solid impurities on the suction line of a borehole pump of the ECV type using a pressure-vacuum hydrocyclone is proposed. It is specified that at field tests of a prototype of new installation technological process is estimated on the pressure-expense characteristic and technological-operational indicators according to requirements of GOST 6134-81 " pumps dynamic. Test method. " In this case, the flow rate of the base pump on water is determined by means of a turbine water meter mounted on a water-lifting pipe with a valve. The performance of the hydraulic elevator is established by the volumetric method, and the head in front of the valve of the pump pressure pipe using an approximate pressure gauge. It is established that the flow-pressure characteristics of the base submersible pump ECV are provided in full (water flow 60-70 m3/h, head - 110-118 m), overload on the electric motor is not detected (ammeter readings are within the permissible limits-68-71 amperes), the degree of water purification is 95-96%. It is noted that the implementation of a flexible packer device with slots and the presence on the surface of the second minihydrocyclone-thickener significantly improves the functioning of the adopted scheme of water treatment. It turned out that with this technology, the overload of the pump motor is reduced by cooling with water without mechanical impurities.

Energy model of electric drive of centrifugal borehole pump

A mathematical model of an electric drive of a centrifugal borehole pump is proposed for evaluating its energy consumption in operating conditions. The model is based on the use of minimum set of technical parameters of the pump, presented in the public data of the manufacturer. The correctness of the calculated formulas is confirmed by experimental data provided in the program for equipment search and selection from Grundfos Product Center. Based on the created model, a comparative analysis of the energy efficiency of products from various manufacturers was made. It is proved that when choosing a centrifugal borehole pump of the local water supply system, it is necessary to pay attention to the energy efficiency indicators of electric drive in order to make a final decision.