Rotary piston pump unloading new technology

I. Preface At present, the domestic railroad light oil tanker trucks are unloaded and unloaded. The unloading process is summed up in the following three ways: First, the vacuum unloading process; and second, the volumetric pump-assisted centrifugal pump unloading process. Third, the submersible pump unloading process. This article describes a new process for unloading oil using a rotary piston pump for future use in new and retrofit tank farms.

Second, the existing unloading process introduction 1, the vacuum unloading process using a vacuum system for priming pump, sweeping warehouse and pumping emptying tank oil operations. The system needs more equipment, such as water ring vacuum pumps, vacuum tanks, vacuum lines, etc., and the vacuum pump water should also consider the winter freezing problem. In addition, when the vacuum pump is working, the exhaust pipe often has a large amount of oil and gas discharged, which is very unsafe, so at present this process has rarely been used in oil depots.

2. Volumetric pump-assisted centrifugal pump unloading process uses a positive displacement pump to replace the vacuum system and realizes centrifugal pumping and sweeping. The system is currently used in many applications, especially for diesel and jet coal oils. The displacement pump used is usually a vane pump or a swing rotor pump. The need to pay attention to the application of this system is that in the process of sweeping the warehouse, due to the presence of oil and gas mixed transmission, the outlet pressure of the sweeper pump will be much lower than the rated value of the pump, so a sweep tank or a low level tank must be installed. Otherwise it will not work.

3. Submersible pump unloading process The submersible pump unloading process has two schemes: First, the unloading process in which the low lift submersible pump and the main oil pump work in series. The second is the process of high-lift submersible pumps directly unloading oil into the tank. The advantages of this process scheme are high reliability of unloading oil and short working time. There is no need to worry about the air resistance of the crane pipe and the problem of pump cavitation, and it is especially effective for unloading gasoline at high temperature in high altitude areas. The disadvantage is that the investment and operating costs are relatively high. Because the submerged oil pump is installed at the mouth of the crane, the operation is inconvenient. In addition, the sweeping system of this scheme cannot be omitted, and the setting method is the same as the centrifugal pump unloading process.

Third, the new oil unloading technology Rotary piston pump unloading process: rotary piston pump is a volumetric pump, with a low speed (400 rev / min), suction capacity (maximum vacuum degree of 0.085MPa), high efficiency (0.7 ~ 0.85), can be gas-liquid two-phase transportation, filtering impurities have low requirements. Because of its superior self-priming ability, it is not necessary to install other pumps as priming pumps for unloading; due to the transport of liquids with solid particles, impurities in sweeping operations have little effect on them. In the unloading process, only one rotary piston pump can be used to complete various operations such as unloading oil, sweeping warehouses, emptying pipelines, and pumping and emptying tank oils. As a result, equipment such as sweep tanks, sweeper pumps and sweeper lines are saved, which not only saves significant investment, but also facilitates operation and management. It is an ideal, economical and practical new unloading process. There are two options for the oil unloading process: First, all cranes share a large-volume rotary piston pump; the advantages of this program are investment, equipment, and management. The disadvantage is that if the flow rate of the selected pump is relatively large, when the last one or two vehicles are unloaded, due to insufficient flow of the pump, vibration and loud noise may occur. The main reason for this is to let the air intake point of the inlet pipe open to solve the problem. . This solution is suitable for unloading traffic between 100 and 200 m3/h, with ample unloading time. The second is to place the pump under the trestle bridge, press one set of three cranes, and set up a small flow (60-80m3/h) rotary piston pump in each group. When the oil is unloaded, all the pumps can work at the same time, thus satisfying the requirements of large flow and quick unloading. A train can be unloaded within three hours. It also avoids the problem of pump vibration due to insufficient flow during unloading to the end. Applicable to short unloading time, large flow and low lift.