CN214465055U

CN214465055U - Surge-proof device for centrifugal compressor

Info

Publication number: CN214465055U
Application number: CN202120417501.5U
Authority: CN
Inventors: 杨金顺; 钱华林; 李啸
Original assignee: Zhejiang Chenxuan Turbine Manufacturing Co ltd
Current assignee: Zhejiang Chenxuan Turbine Manufacturing Co ltd
Priority date: 2021-02-25
Filing date: 2021-02-25
Publication date: 2021-10-22
Anticipated expiration: 2031-02-25

Abstract

The utility model relates to a centrifugal compressor surge-proof device. The utility model discloses a one-level manometer of admitting air, one-level pressure teletransmission changer, automatically regulated valve, unit return line, last exhaust pressure gauge, last stage pressure teletransmission changer. The device is connected with a compressor unit to realize surge prevention of the centrifugal compressor. The utility model discloses utilize the compressor to import and export and compress the ratio, the automatic control centrifugal compressor backward flow is in order to prevent the compressor surge. The influence of the air inlet condition and the air outlet condition is comprehensively considered, so that the condition that the assumed condition for controlling the backflow of the compressor cannot exist stably due to the fact that the air inlet state of the compressor deviates from the designed value is avoided, and the situation that equipment already surges when the equipment does not reach the expected backflow condition is very likely to occur. Compared with other centrifugal compressor backflow anti-surge methods, the method has the advantages that a plurality of field and remote pressure data can be compared, and the method is more effective, practical and reliable.

Description

Surge-proof device for centrifugal compressor

Technical Field

The utility model belongs to the technical field of centrifugal compressor, a centrifugal compressor surge-proof device is related to.

Background

The basic working principle of the centrifugal compressor is that the impeller rotating at high speed applies work to gas, so that the pressure of the gas is increased and the speed is increased by mechanical energy. After leaving the impeller, the gas flows through the diffuser for speed reduction and pressure expansion, so that the kinetic energy of the gas is converted into pressure energy, and the compression process is completed.

When the flow rate of the centrifugal compressor is excessively reduced, a stall phenomenon occurs in the gas with respect to the impeller flow passage, and the gas flow rate and the discharge pressure of the compressor periodically fluctuate at a low frequency and a large amplitude, thereby causing strong vibration of the machine, which is called surging of the compressor. Surge is an inherent characteristic of centrifugal compressors and occurs when the flow rate is small to a certain limit for any one centrifugal compressor. When the compressor surges, each running part of the compressor can generate serious vibration, friction and impact, so that serious damage such as abrasion, ablation, breakage and the like can be generated, and the situation that each link of design, manufacture, operation and the like of the centrifugal compressor needs to be strictly prevented.

At present, centrifugal compressors are all provided with unit backflow (commonly called small backflow) so as to facilitate parallel off-line operation during start and stop, adjust unit output flow and prevent compressor surging. The existing unit backflow operation modes comprise manual operation and automatic operation, wherein the manual operation is mainly used for large-flow circulation before grid connection and after grid disconnection of the unit, the automatic operation is a normal control mode during daily operation of a compressor, and the main function is to ensure necessary flow under the daily operation state of the unit so as to prevent surging of a main machine when the flow is too low.

The existing centrifugal compressor set reflux self-control mode mainly includes flow control and exhaust pressure control. However, they have the following disadvantages:

1. the intake air (pressure, temperature, etc.) state is assumed to be the design value, but in actual operation, in order to adjust the output flow of the compressor, save energy and meet the system safety requirement, the intake valve needs to be adjusted frequently, the intake state of the compressor often deviates from the design value, so that the assumed condition for controlling the backflow of the compressor cannot exist stably, and the surge is likely to occur before the equipment does not reach the expected backflow condition.

2. The flow meter matched with the compressor is not accurate, and if the flow measured by the flow meter is lower than an actual value, the automatic reflux valve of the compressor is opened when the automatic reflux valve of the compressor is not opened, so that the conveying capacity of the compressor is reduced, and the reflux of the compressor is difficult to control.

3. The flow meter is expensive and basically has no redundant design, so that the reliability of controlling the backflow of the compressor by the flow is not high.

4. In case of emergency, when the source of the inlet medium is interrupted and the system backflow (commonly called large backflow) is not in a self-control state, the inlet pressure of the compressor is rapidly reduced, and the compressor still surges even if the exhaust pressure is not high.

The utility model discloses to the drawback of above-mentioned current anti-surge method, the influence of centrifugal compressor density of admitting air to compressor performance (pressure, flow) is considered comprehensively, promptly under the unchangeable condition of the component that admits air, centrifugal compressor's design compression ratio can remain unchanged basically. The utility model provides an anti-surge method of unit backward flow is controlled with compression ratio (referring to the absolute pressure ratio of compressor last stage exhaust and one-level admit air) to the problem that current anti-surge automatic control mode exists has been solved, the utility model discloses have very important using value and industrial prospect.

Disclosure of Invention

The utility model aims at providing a centrifugal compressor surge protector.

The utility model discloses a one-level manometer of admitting air, one-level pressure teletransmission changer, automatically regulated valve, unit return line, last exhaust pressure gauge, last stage pressure teletransmission changer. The device is connected with a compressor unit to realize surge prevention of the centrifugal compressor. The compressor unit comprises a compressor, an interstage cooler and a final stage cooler;

the primary air inlet pressure gauge and the primary pressure remote transmitter are arranged on a primary air inlet pipeline of the compressor; the air inlet of the inter-stage cooler is connected with the first-stage exhaust port of the compressor, and the air outlet of the inter-stage cooler is connected with the last-stage air inlet of the compressor; the air inlet of the final cooler is connected with the final exhaust port of the compressor, and the air outlet of the final cooler is connected with the medium distribution table; a final-stage exhaust pressure gauge and a final-stage pressure remote transmitter are arranged at an air outlet of the final-stage cooler, and the air outlet of the final-stage cooler is connected with a first-stage air inlet of the compressor through a unit return pipeline to form internal circulation; the machine set reflux pipe is provided with an automatic regulating valve and a manual bypass valve, and the automatic regulating valve and the manual bypass valve are installed in parallel.

The compressor last-stage air inlet, the compressor last-stage air outlet, the compressor first-stage air outlet and the compressor first-stage air inlet are connected with a pipeline through flanges.

The air inlet of the interstage cooler, the air outlet of the interstage cooler, the air inlet of the final stage cooler and the air outlet of the final stage cooler are connected with pipelines through flanges.

The self-regulating valve is opened when the compression ratio reaches 95% of the compression ratio and closed when the compression ratio reaches 105%, and the self-regulating valve is linearly regulated.

The utility model discloses utilize the compressor to import and export and compress the ratio, the automatic control centrifugal compressor backward flow is in order to prevent the compressor surge. The influence of the air inlet condition and the air outlet condition is comprehensively considered, so that the condition that the assumed condition for controlling the backflow of the compressor cannot exist stably due to the fact that the air inlet state of the compressor deviates from the designed value is avoided, and the situation that equipment already surges when the equipment does not reach the expected backflow condition is very likely to occur. Because the unit generally has a plurality of on-site and remote pressure data which can be compared, the method is more effective, practical and reliable than other centrifugal compressor backflow anti-surge methods. The reflux can be controlled only by increasing the compression ratio of the unit, and the investment is hardly increased.

Drawings

Fig. 1 is the control diagram of the primary medium of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in figure 1, the surge-proof device of the centrifugal compressor comprises a primary air inlet pressure gauge 1, a primary pressure remote transmission transmitter 2, an automatic regulating valve 3, a unit return pipeline 4, a final exhaust pressure gauge 7 and a final pressure remote transmission transmitter 8. The device is connected with a compressor unit to realize surge prevention of the centrifugal compressor. The compressor unit comprises a compressor, an interstage cooler 5, a final stage cooler 6 and an upper computer.

The primary air inlet pressure gauge 1 and the primary pressure remote transmitter 2 are arranged on a connecting pipe of a primary air inlet 12 of the compressor, and the primary air inlet 12 of the compressor is connected with the connecting pipe through a flange; a first-stage exhaust port 11 of the compressor is connected with an air inlet of the interstage cooler 5 through a pipeline and a flange, an air outlet of the interstage cooler 5 is connected with a last-stage air inlet 9 of the compressor through a pipeline and a flange, and a last-stage exhaust port 10 of the compressor is connected with an air inlet of the last-stage cooler 6 through a pipeline and a flange; the air outlet of the final cooler 6 is connected to the medium distribution station through a pipeline and a flange, a final exhaust pressure gauge 7 and a final pressure remote transmission transmitter 8 are arranged on the connecting pipeline of the air outlet of the final cooler 6, and the air outlet is also connected with a first-stage air inlet 12 of the compressor through a set return pipeline 4 to form an internal circulation, an automatic regulating valve 3 and a manual bypass valve 13 are arranged on the set return pipeline 4, and the automatic regulating valve 3 and the manual bypass valve 13 are installed in parallel.

The device is based on the following anti-surge control method of the centrifugal compressor, and the method comprises the following specific steps:

according to design parameters, the compressor surge point compression ratio is calculated and set (can also be obtained through actual measurement of the actual operation condition on site), if the surge point compression ratio is 3.5, an alarm signal is sent out when the operation compression ratio is 3.3, when the operation compression ratio is 3.4, the automatic regulating valve is started, the flow of the compressor is increased, the operation compression ratio is reduced, the condition that the compressor enters a surge area to operate when the operation compression ratio is more than or equal to 3.5 is avoided, and when the operation compression ratio is more than or equal to 3.5, compressor unit equipment is interlocked and stopped. All the data required by the anti-surge control method are different according to different working conditions and equipment, and the set compression ratio is input into an upper computer according to the corresponding working conditions and the equipment before the equipment leaves a factory.

The use of centrifugal compressors is generally defined and unique, so that the medium composition is fixed, and on the premise that changes in the inlet pressure and temperature result in changes in the nominal flow rate and pressure raising capability of the compressor. But the compression ratio achievable by the centrifugal compressor is constant. When the impeller is designed, according to the outlet absolute pressure (namely, the outlet pressure of the compressor: 0.35MPa (A)) corresponding to the design parameter provided by a user at the rated flow, the outlet absolute pressure is divided by the given inlet absolute pressure (namely, the inlet pressure of the compressor: 0.09MPa (A)) to calculate the rated compression ratio (the obtained compression ratio is 0.35/0.09 is 3.89).

In the conventional compressor, if surge occurs or the compressor enters an unstable operation state due to a rise in the discharge pressure, the surge compression ratio is calculated from the discharge pressure at that time, and the product of the calculated surge compression ratio and the discharge pressure is multiplied by 0.9 to obtain the rated compression ratio.

At the time of setting the parameters of the automatic regulating valve, the automatic regulating valve is started to be opened when the compression ratio reaches 95% of the rated compression ratio and is closed when the compression ratio reaches 105% of the rated compression ratio, and linear regulation is carried out between the starting and the closing. The utility model discloses signal acquisition is easy, and data reliability is higher, prevents that the compressor surge is timely reliable, because of improving on normal configuration basis, the event increases the investment volume and can neglect almost.

Claims

1. The surge-proof device of the centrifugal compressor is characterized in that: the system comprises a primary air inlet pressure gauge (1), a primary pressure remote transmission transmitter (2), an automatic regulating valve (3), a unit return pipeline (4), a final-stage exhaust pressure gauge (7) and a final-stage pressure remote transmission transmitter (8); the device is connected with a compressor unit to realize surge prevention of the centrifugal compressor; the compressor unit comprises a compressor, an interstage cooler (5) and a final stage cooler (6);

the primary air inlet pressure gauge (1) and the primary pressure remote transmitter (2) are arranged on a pipeline of a primary air inlet (12) of the compressor; the air inlet of the inter-stage cooler (5) is connected with a first-stage exhaust port (11) of the compressor, and the air outlet of the inter-stage cooler (5) is connected with a last-stage air inlet (9) of the compressor; the air inlet of the final cooler (6) is connected with the final exhaust port (10) of the compressor, and the air outlet of the final cooler (6) is connected with the medium distribution table; a final-stage exhaust pressure gauge (7) and a final-stage pressure remote transmitter (8) are arranged at an air outlet of the final-stage cooler (6), and the air outlet of the final-stage cooler (6) is connected with a first-stage air inlet (12) of the compressor through a unit return pipeline (4) to form internal circulation; an automatic regulating valve (3) and a manual bypass valve (13) are arranged on the set return pipe (4), and the automatic regulating valve (3) and the manual bypass valve (13) are arranged in parallel.

2. The centrifugal compressor anti-surge apparatus of claim 1, wherein: the compressor last-stage air inlet (9), the compressor last-stage exhaust outlet (10), the compressor first-stage exhaust outlet (11) and the compressor first-stage air inlet (12) are connected with a pipeline through flanges.

3. The centrifugal compressor anti-surge apparatus of claim 1, wherein: the air inlet of the interstage cooler (5), the air outlet of the interstage cooler (5), the air inlet of the final cooler (6) and the air outlet of the final cooler (6) are connected with pipelines through flanges.

4. The centrifugal compressor anti-surge apparatus of claim 1, wherein: the self-regulating valve (3) is opened when the compression ratio reaches 95% of the compression ratio and closed when the compression ratio reaches 105%, and the self-regulating valve is linearly regulated.