Abstract: According to China Coal Yulin Magnetic Float Level Gauge, the first stage of the suction tank of the gas compressor is prone to high level interlocking risks, the introduction of a pump trap in the magnetic float level meter solves this problem, and introduces the working principle and characteristics of the pump trap.
1 topic backgroundChina Coal Shaanxi Yulin Energy Chemical Co., Ltd. 600,000 t/a magnetic float level gauge olefin separation device reaction gas compressor 1160V401 (referred to as the first suction tank), because the magnetic float level gauge device water scrubber top product gas contains A certain amount of water can easily cause a section of the suction tank to be filled with liquid. Under normal working conditions, it is necessary to start the first stage of the reaction gas compressor suction tank bottom pump 1160P401 for processing. The centrifugal pump must meet a certain liquid level in the suction tank before it can be started, otherwise it will cause the pump to evacuate and damage the equipment. However, with the long-term operation, the trays of the washing column of the magnetic float level gauge will be blocked to varying degrees. Once the production of the magnetic float level gauge fluctuates or the tray is suddenly dredged, a very large amount of liquid will be produced. In a very short period of time, the liquid level of the suction tank will rise sharply. In this emergency state, the bottom pump of the suction tank cannot be discharged in time, causing the high liquid level interlocking stop of the reactant gas compressor. To solve this problem, analyze how to realize that a small amount of liquid can be discharged from a suction tank, and can realize a large discharge volume in an instant. Using Daqing Petrochemical E2 set of ethylene plant for reference, the magnetic float level gauge was introduced into the pump trap application.2 Introduction and characteristics of pump trap2.1 Introduction and working principle of pump trapThe scientific name of the pump trap is a condensate recovery pump. It is a mechanical pump product that uses compressed air or high-pressure steam as a power source without electric drive. It can greatly improve the safety performance of the system, reduce the operating cost of the system, and simplify the system. Installation and maintenance requirements. The main working principle is that the condensed water enters the pump body through the front-end water collection tank and relies on the designed static pressure difference. The floating ball linkage mechanism in the pump body will rise as the liquid level rises. When the liquid level rises to a certain height , Will trigger a spring mechanism that controls the opening and closing of the power gas valve. When the power gas inlet valve is opened, power gas will be introduced, and the condensed water will be forced out by the pressure of the power gas. When the liquid level drops to a certain height At the same time, the spring mechanism will be triggered again to close the intake valve and open the exhaust valve at the same time to discharge the high pressure gas in the pump body and reduce the pressure in the pump body so that the condensed water can enter the pump body smoothly. This reciprocating cycle realizes the drainage function. 1 is its principle diagram, and Figure 2 is a partial enlarged view of the spring mechanism.2.2 The characteristics of the pump trapThe main features of the pump trap are as follows:(1) The floating ball linkage mechanism is adopted to control the switch of the pump without a continuous rotating impeller, which can completely avoid cavitation damage and has a long service life.(2) All parts are purely mechanically designed, without any electrical appliances or other accessories, which can be used in dangerous working conditions and are safer and more reliable.(3) The problem of non-moving seal or packing seal leakage.(4) Using power steam or compressed air as the power source, there is no power consumption during the use process, which greatly saves operating costs.(5) The internal parts of stainless steel can ensure the corrosion resistance and erosion resistance of the equipment, and ensure the reliability and service life of the equipment.(6) The special Inconel material spring has excellent mechanical strength and can meet the fatigue resistance required by the frequent action of the spring to ensure the timeliness and reliability of the pump action.(7) The precise calculation design of the internal float stroke can ensure that the pump discharges and enters water in time without interference, and ensures the reliability of operation(8) The precise machining of the sealing surfaces of the inlet and exhaust valves can ensure its excellent and reliable sealing performance(9) The overall skid-mounted design, the structure is simple, compact, the installation and debugging are simple, the installation space is small, which can greatly save space resources, while maintaining simple maintenance and low cost.3 Selection and calculation of pump trapAccording to the process conditions of the magnetic float level gauge and the conditions available on site, communicate with the technical personnel of Spirax Sarco Co., Ltd., under the power of 0.6MPa and the back pressure of 0.1MPa, according to the displacement curve of the SARPTIV pump series (as shown in the figure) 3).It can be calculated that the displacement of a single SARPTIV DN100 ANSI150 is 26 580 kg/h, and the displacement of the double pump set is 53 160 kg/h, which can meet the design requirements of the maximum flow rate of 50 000 kg/h.Therefore, the selection of the condensate recovery pump is: SARPTIV DN100 ANSI150 open double pump combination.4 Application of pump trap in magnetic float level gaugeDue to the fluctuation of the magnetic float level gauge and the washing tower, the high liquid level interlocking of the reaction gas compressor caused the hidden danger, and the technical improvement measures were proposed for reference to the Daqing Petrochemical E2 set of ethylene application pump traps. Under the design of Zhongyi Ameco Foster Wheeler Engineering Co., Ltd., during the overhaul in May 2017, a base was added to the south side of a 1160V401 suction tank, and a double pump trap was placed on the base, and a suction tank was placed on the base. Connect the bottom wire to the pump trap collection tank, connect the nitrogen line to the pump trap, and connect the liquid discharge at the bottom of the tank to the torch. Figure 4 is a schematic diagram of the pump trap piping, and Figure 5 is an external view of the pump trap.5 The effect of pump trap applicationThe application of the pump trap can effectively solve the operation difficulties caused by the product gas carrying liquid, and also ensure the stable operation of the product gas compressor, creating favorable conditions for the long-period stable operation of the device.Since nitrogen is used as the power source, there is no power consumption during the use process, and liquid is automatically discharged, and no liquid does not consume nitrogen, which greatly saves operating costs. In June 2017, Zhongmei Yulin Magnetic Float Level Gauge applied a pump trap after the start-up, and the reaction gas compressor did not stop interlocking due to the high level of 1160V401 in a suction tank. Each stop of the product gas compressor will cause the magnetic float level gauge to fully ignite the torch, and the economic loss per hour of stopping will reach millions. The pump trap application avoids the huge loss caused by the product gas compressor tripping.
Post time: 21-09-21