METHOD AND HIGH-PRESSURE SYSTEM FOR DETERMINING A FLOW CONTROL VARIABLE OF A FLUID FLOW FLOWING THROUGH A HIGH-PRESSURE-SIDE HIGH-PRESSURE PUMP OUTLET OF A HIGH-PRESSURE PUMP

Abstract

A method and a high-pressure system for determining a flow control variable of a fluid flow flowing through a high-pressure-side high-pressure pump outlet of a high-pressure pump are provided. An externally arranged ultrasonic measuring device measures a flow speed of a fluid flow flowing through a pipe of the high-pressure-side high-pressure pump outlet. A use of an ultrasonic measuring device is provided for determining a flow value to be achieved of a fluid flow flowing through a thick-walled pipe. The ultrasonic measuring device is arranged on the outside on the thick-walled pipe of the high-pressure pump outlet. The pipe has a ratio of the internal diameter to the external diameter of 1:1.5 to 1:5. The ultrasonic measuring device dynamically measures the flow speed of the fluid flow and transmits this measured flow speed to an evaluation unit to compute a current flow value and the flow control variable.

Claims

1-15. (canceled)

16. A method for determining a flow control variable of a fluid flow flowing through a high-pressure-side high-pressure pump outlet of a high-pressure pump, the method comprising: measuring a flow speed of the fluid flow flowing through a pipe of the high-pressure-side high-pressure pump outlet by means of at least one ultrasonic measuring device including an externally arranged ultrasonic measuring device, to obtain a measurement result of the flow speed, transmitting the measurement result of the flow speed to an evaluation unit; and computing a present flow value and the flow control variable from the measurement result of the flow speed by means of the evaluation unit.

17. The method as claimed in claim 16, wherein the measurement of the flow speed and the transmission of the measurement result and the computation of the present flow value and the flow control variable to be achieved take place dynamically.

18. The method as claimed in claim 17 wherein the evaluation unit computes at least one of the present flow value by means of an equation method and the flow control variable by means of a comparison method.

19. The method as claimed in claim 18 wherein the flow speed measured by means of the ultrasonic measuring device is corrected in consideration of further provided or determined information data, including at least one of a temperature of the fluid flow and a pressure of the fluid flow, wherein the mathematical relationships required for this purpose are determined theoretically or empirically.

20. A high-pressure system having a high-pressure pump having a high-pressure pump inlet and a high-pressure-side high-pressure pump outlet, wherein at least one ultrasonic measuring device includes an externally arranged ultrasonic measuring device that is externally arranged on the high-pressure-side high-pressure pump outlet to measure a flow speed of a fluid flow flowing through a pipe of the high-pressure-side high-pressure pump outlet.

21. The high-pressure system as claimed in claim 20 wherein the high-pressure-side high-pressure pump outlet is a thick-walled pipe having a ratio of the pipe internal diameter (Di) to the pipe external diameter (Da) 1:1.5 to 1:5 and the ultrasonic measuring device is arranged on the outside on this thick-walled pipe.

22. The high-pressure system as claimed in claim 21 wherein the high-pressure system has a reactor chamber for carrying out a chemical, thermal, thermodynamic, or mechanical reaction and the thick-walled pipe that is arranged directly or indirectly between the reactor chamber and the high-pressure pump.

23. The high-pressure system as claimed in claim 22 wherein the high-pressure system is a system for polymerizing monomers, in particular ethene (ethylene) and propene (propylene).

24. The high-pressure system as claimed in claim 23 wherein the thick-walled pipe comprises a material from the group of metal alloys, such as high-alloyed or low-alloyed steels, titanium alloys, copper alloys, nickel alloys, tantalum alloys, chromium alloys, or cobalt alloys.

25. The high-pressure system as claimed in claim 24 wherein the thick-walled pipe is fixed by means of a flange on the high-pressure pump, which flange has a flow channel having a continuously conically enlarging section at least in sections - in the flow direction - wherein this conical section extends at least over a third, in particular over half of the total length of the flow channel.

26. The high-pressure system as claimed in claim 25 wherein the internal diameter (Di) of the thick-walled pipe has a section continuously enlarging at least in sections, a cylindrical section, and a section continuously tapering at least in sections.

27. The high-pressure system as claimed in claim 26 wherein in the flow direction before the ultrasonic measuring device, a straight, curve-free calming section having a length which corresponds to at least five times the internal diameter of the thick-walled pipe is formed, and, in the flow direction after the ultrasonic measuring device, a straight, curve-free calming section having a length which corresponds to at least three times the internal diameter (Di) of the thick-walled pipe are formed.

28. The high-pressure system as claimed in claim 27 wherein the high-pressure pump is designed to generate a pressure between 1000 and 6000 bar.

29. The high-pressure system as claimed in claim 27 wherein the ultrasonic measuring device is connected to an evaluation unit to transmit signals, in order to transmit the measurement result of the flow speed of the fluid flow to the evaluation unit.

30. A use of an ultrasonic measuring device for determining a flow value of a fluid flow flowing through a thick-walled pipe of a high-pressure-side high-pressure pump outlet of a high-pressure pump, wherein the ultrasonic measuring device is arranged externally on the thick-walled pipe of the high-pressure pump outlet, which pipe has a ratio of the internal diameter (Di) to the external diameter (Da) of 1:1.5 to 1:5, in such a way that this ultrasonic measuring device dynamically measures the flow speed of the fluid flow and transmits this measured flow speed as a measurement result to an evaluation unit to compute a present flow value and a flow control variable to be achieved from the measurement result.

Description

[0042] FIG. 1A shows a perspective view of a detail of a thick-walled pipe having ultrasonic measuring devices arranged thereon in a series circuit,

[0043] FIG. 1B shows a perspective view of a detail of a thick-walled pipe having ultrasonic measuring devices arranged thereon in a parallel circuit,

[0044] FIG. 2 shows a schematic illustration of an embodiment of an evaluation unit,

[0045] FIG. 3 shows a sectional illustration of an embodiment of a thick-walled pipe having a flange to be arranged on a high-pressure-side high-pressure pump outlet, and

[0046] FIG. 4 shows a circuit diagram of an embodiment of a high-pressure system.

[0047] Elements having identical function and mode of action are each provided with the same reference signs in FIGS. 1 to 4.

[0048] FIGS. 1A and 1B each schematically show a perspective view of a detail of a thick-walled pipe 1 having ultrasonic measuring devices 10, 11 arranged thereon. In the embodiment shown in FIG. 1A, the ultrasonic measuring devices 10, 11 are arranged in a series circuit. This means that both ultrasonic measuring devices 10, 11 are fastened on the same side of the pipe 1. This arrangement of the ultrasonic measuring devices 10, 11 is suitable in particular for using a reflection mode and for generating an even number of sound paths 2, 3. As schematically shown in FIG. 1A, two sound paths 2, 3 (dotted line), namely a first sound path 2 between the one (first) ultrasonic measuring device 10 and the inner wall of the pipe 1 and an associated (second) sound path 3, in particular connected to the first sound path 2, between the inner wall of the pipe 1 and the further (second) ultrasonic measuring device 11. Since the further ultrasonic measuring device 11 also emits signals, in particular ultrasonic waves, the two sound paths 2, 3 are therefore also used thereby, wherein therefore, however, the signals/soundwaves run opposite to the first signals/soundwaves. In the embodiment according to FIG. 1B, the ultrasonic measuring devices 10, 11 are essentially arranged in a parallel circuit. This means that the ultrasonic measuring devices 10, 11 are arranged on opposite sides of the pipe 1. The ultrasonic measuring devices 10, 11 have, viewed in the flow direction, a distance offset in relation to one another, therefore are not directly opposite to one another. Rather, the ultrasonic measuring devices 10, 11 are arranged spaced apart from one another viewed in the flow direction. This arrangement of the ultrasonic measuring devices 10, 11 is advantageously suitable for the use of the transmission mode, in which an odd number of sound paths 2 is generated. As is apparent in FIG. 1B, one sound path 2 is generated between the one (first) ultrasonic measuring device 10 and the other (second) ultrasonic measuring device 11. The soundwaves originating from the ultrasonic measuring devices 10, 11 are therefore not reflected on the inner surface of the pipe 1, rather penetrate the pipe 1 from one side to the other side.

[0049] As shown in FIGS. 1A and 1B, the ultrasonic measuring devices 10, 11 are arranged on the exterior/outside on the thick-walled pipe 1 and are each fixed by means of a fastening element 12, a fastening belt here, for example. The thick-walled pipe 1 has an internal diameter Di and an external diameter Da. Both ultrasonic measuring devices 10, 11 dynamically measure the flow speed of the flowing fluid and transmit the measurement results continuously to an evaluation unit 50, as schematically shown in FIG. 2.

[0050] The evaluation unit 50 schematically shown in FIG. 2 advantageously has a large number of units. By means of the receiving unit 55, the evaluation unit 50 therefore receives the measured values (arrow 60) transmitted by the ultrasonic measuring devices 10, 11 with respect to the flow speed or flow velocity of the fluid flowing through the thick-walled pipe 1 (cf. FIG. 1). The received data/values are then passed on either directly, thus directly to a computing unit 51 (arrow 61), or transmitted non-directly, thus indirectly first to a memory unit 54 (arrow 62) and then via this memory unit 54, which is used, inter alia, for temporarily storing the data, to the computing unit 51 (arrow 63). The computing unit 51 determines from the presently sent data a present flow value, such as a volume flow and/or mass flow. This determined present flow value is then passed on to the comparison unit 52, which is a part of the computing unit 51. The comparison unit 52 compares the received flow value to predetermined minimum SETPOINT flow values and maximum SETPOINT flow values. The result is then transmitted to a deviation determination unit 53, which is also advantageously a part of the computing unit 51. The deviation determination unit 53 determines the manipulated variable, in particular the flow control variable or the flow control value, which it requires to regulate the high-pressure pump in such a way that the measured flow speed and the flow value to be determined therefrom are within predetermined limiting values. These values/data are then transmitted either directly (immediately) in the form of command data to a transmitting unit 56 (arrow 64) or non-directly (indirectly) via the above-mentioned memory unit 54 (arrow 65 and arrow 66). The transmitting unit 56 then transmits the data or manipulated variables, in particular the flow control variable or the flow control value, on to final control elements (not shown here) (regulating and control units) of the high-pressure pump (arrow 67). These final control elements then ensure a demand-controlled regulation of the high-pressure pump.

[0051] FIG. 3 shows a sectional illustration of an embodiment of a thick-walled pipe 1 having a flange 20 to be arranged on a high-pressure-side high-pressure pump outlet (not shown here). The thick-walled pipe 1 was arranged leak-tight on the flange 20 using suitable seal elements 21 and has an internal diameter Di and an external diameter Da. The flange 20 has a flow channel 22, which extends starting from the high-pressure-side high-pressure pump outlet (not shown here) to the thick-walled pipe 1. The flow channel 22 has a conical section 23, which in particular continuously conically enlarges in the flow direction S. The distal end 24 of the flow channel 22, which is oriented toward the thick-walled pipe 1, advantageously has an internal diameter di which corresponds to at least two-thirds of the internal diameter Di or the pipe internal diameter Di of the thick-walled pipe 1. The internal diameter di of the flow channel 22 is advantageously equal to the internal diameter Di of the thick-walled pipe 1.

[0052] FIG. 4 schematically shows a circuit diagram of a high-pressure system 30. This is primarily a high-pressure system for producing ethylene copolymers in the reactor 31, which can advantageously be designed as a stirring reactor. Alternatively, it is conceivable that the high-pressure system 30 shown in FIG. 4 has a pipe reactor. Ethylene and/or propylene is/are compressed via the compressors (primary compressor, hyper compressor) and pumped into the reactor 31. The flow direction S results here. Before the reactor 31, thus viewed opposite to the flow direction S, the possible high-pressure pumps 32 are arranged, which are connected in particular via their high-pressure-side high-pressure pump outlet to the reactor 31. These high-pressure pumps 32 are advantageously used to pump in initiators (sometimes also referred to as catalysts, peroxides), modifiers, and/or comonomers. In addition, the high-pressure pumps 32 are advantageously used as control elements (regulating and control units) in the high-pressure system 30, since the amount of fluid pumped in influences the polymerization process, and sometimes also first initiates it. Among other things, the temperature and the degree of polymerization are regulated, and the quality of the produced plastic is therefore decisively influenced, by precise metering of the fluids to the high-pressure medium.

TABLE-US-00001 List of reference signs 1 thick-walled pipe 2 (first) sound path 3 (second) sound path 10, 11 ultrasonic measuring device 20 flange 21 seal element 22 flow channel 23 continuously conically enlarging section 24 distal end 30 high-pressure system 31a, b reactor/reactor chamber 32 high-pressure pump 50 evaluation unit 51 computing unit 52 comparison unit 53 deviation determination unit 54 memory unit 55 receiving unit 56 transmitting unit 60 input of the measured values 61 transmission of the measured values to computing unit 62 transmission of the measured values to memory unit 63 transmission of the measured values to computing unit 64 transmission of the command data to transmitting unit 65 transmission of the command data to memory unit 66 transmission of the command data to transmitting unit 67 transmission of the command data to final control elements Da external diameter of thick-walled pipe/pipe external diameter Di internal diameter of thick-walled pipe/pipe internal diameter di internal diameter of flow channel S flow direction