JP4301632B2 - Dry gas seal integrity management method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry gas seal soundness management method and apparatus, and is capable of predicting in advance a compressor trip time mainly due to deterioration of a dry gas seal of a centrifugal compressor. An abnormality of the gas seal caused by the deterioration of the next seal (such as an O-ring) can be predicted at an early stage.
[0002]
[Prior art]
In general, the method of detecting an abnormality in a tandem dry gas seal attached to a centrifugal compressor is to monitor the state of the primary gas leak, and when the measured value exceeds a predetermined level, an alarm is issued. It is a security system that manages in two stages to trip the compressor.
[0003]
FIG. 7 is a view showing a part of the tandem dry gas seal of the centrifugal compressor as described above, and shows only the gas seal on the suction side of the compressor. In the figure, a rotation side seal member 51 is attached around the rotation shaft 50, and a stationary side seal member 52 is disposed in close proximity to the rotation side seal member 51. The stationary seal member 52 is supported by the casing 53. A compressor (not shown) compresses process gas and discharges compressed gas, and this gas mainly contains N ₂ or H ₂ gas. The process gas 60 becomes a clean gas by the filter 61, the flow rate of which is adjusted by the flow rate control valve 62, one is supplied from the pipe 63 to the suction side gas seal, and the other is supplied from the pipe 64 to the exhaust side gas seal (not shown). Is done.
[0004]
The gas supplied from the pipe 63 is guided to a seal gas inlet 54 provided in the stationary side seal member 52, passes through a gap between the stationary side seal member 52 and the rotation side seal member 51, and is provided in the stationary side seal member 51. Most of the gas flows out from the sealed gas outlet 55 and the remaining gas flows out from the sealed gas outlet 56 to seal between the rotary shaft 50 and the casing 53. Seal gas from the seal gas outlet 55 flows out to the flare 64 and is burned to be released from the chimney to the atmosphere, and a small amount of gas from the seal gas outlet 56 is released to the outside through the exhaust pipe 65.
[0005]
In the dry gas seal as described above, the operator constantly monitors the state of the gas seal with the monitoring unit 70, and when the flow rate of the flow meter 65 reaches the flow rate value determined for preventive maintenance, the signal of the pressure transmitter 71 When the alarm device 72 is activated and then the pressure of the seal gas reaches a predetermined value and the pressure switch 73 is activated, a trip signal S is generated to trip the compressor.
[0006]
FIG. 8 is a detailed system diagram of the monitoring unit 70 described above. In the figure, when the gas flow rate set in advance for safety is reached, the operator activates the pressure transmitter 71 to activate the alarm 72, and then the pressure of the sealing gas is set to three pressure switches 73 in advance from the viewpoint of preventive safety. -1, 73-2, 73-3, the seal gas pressure rises, and when any two of these three pressure switches 73-1 to 73-3 are activated, the compressor trips A signal S is generated.
[0007]
[Problems to be solved by the invention]
The above-mentioned compressor dry gas seal safety system only issues an alarm or outputs a compressor trip signal only for the instantaneous detected value of the seal gas, and an abnormal dry gas seal is detected. It is not a system that can predict aged health after occurrence. Therefore, the assessment of soundness over time and the treatment when an abnormality occurs can only be dealt with based on the experience of the operator.
[0008]
According to the applicant's experience, the gas seal abnormality is caused by the following two methods.
[0009]
1) Gas seal abnormalities rapidly develop due to start, stop, and sudden changes in operating conditions. In general, since a sudden abnormality develops due to the protrusion of the O-ring or the like, trend management is difficult for this cause.
[0010]
2) Abnormalities in the gas seal gradually develop due to liquid, foreign matter mixing, or secondary seal deterioration (deterioration of O-ring, etc.). Abnormalities in the gas seal due to this cause proceed for several days to several weeks and develop into serious troubles.
[0011]
Therefore, the present invention predicts the abnormality of the dry gas seal in advance, estimates the life of the gas seal, and systematically shuts down the compressor based on the estimated value, and the dry gas seal soundness management method and its An object of the present invention is to provide an apparatus.
[0012]
[Means for Solving the Problems]
The present invention is to solve the problems described above, provides a way of the following (1) to (3).
[0013]
(1) From the actual data on the amount of gas leak from the dry gas seal part of the compressor to the approximate curve of the amount of gas leak from the start of operation until the time to become the amount of gas leak to which the compressor should be tripped, Plotting and predetermining by extending this tendency; measuring the gas leak amount at arbitrary time intervals during the operation of the compressor by the detection means; comparing the measured value of the same number of points with the approximate curve; from the trip time of the approximate curve, a health management method of de Rye gas seal you estimate the arrival time until trip the compressor from the measured time during the operation, leakage amount of the gas cyclone A method for managing the integrity of a dry gas seal, which is estimated from the amount of foreign matter such as carbon contained in a gas separated by a gas separator .
[0015]
( 2 ) The container of the cyclonic separator is a transparent container, and the amount of the gas leak is estimated from the image of the foreign matter by photographing the foreign matter accumulated in the lower part of the separator with a camera. The method according to ( 1 ).
[0016]
( 3 ) The method according to ( 1 ), wherein the foreign matter is taken out by suction with a suction device outside the container of the cyclonic separator.
[0019]
The soundness management method for dry gas seals of the present invention is based on the invention of (1). First, among the performance data from which the amount of gas leak from the dry gas seal portion is extracted, a reference value (for example, specified in design) Using data exceeding the guaranteed leakage amount x 1.8), from the increasing tendency of these data to the amount of leakage that causes the compressor to trip (for example, setting the guaranteed leakage amount x 8) An approximate curve of the amount of gas leak in the time zone is obtained in advance. Next, measure several points of gas leak at a predetermined time interval from an arbitrary time during operation, and refer to the approximate curve obtained previously for these measured values until the trip value is reached from the measured value during operation. Obtain a curve and estimate the time it takes to trip the compressor from the measured time. The amount of gas leak occurs due to wear at the dry gas seal portion and is proportional to the amount of carbon contained in the gas. Therefore, the above method is carried out by measuring the amount of foreign matter such as carbon. For that purpose, a cyclone separator is used to separate foreign substances from the gas and this amount is measured.
Therefore, in the past, the operator measured and read the leak amount each time and determined whether or not to continue the operation based on experience each time, but the time until the trip was reached in the normal deterioration of the compressor was determined in advance. Systematic shutdown of the compressor. Moreover, the preparation for the stop of the related plant for that purpose can also be made systematically, and the reliability of not only the compressor but the operation of the whole plant is improved.
[0020]
In ( 2 ) of the present invention , the separation container is made transparent, and the amount of foreign matter is measured from the outside of the container with a camera. In ( 3 ), the amount of foreign matter is sucked out of the container, and the amount This makes it easy to measure the amount of gas leak.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a system diagram of an apparatus for carrying out the dry gas seal soundness management method of the present invention, and is a diagram according to first, second and third embodiments which will be described later. In the drawing, a process gas is sucked into a compressor 80 from a gas suction port 81, compressed by the compressor 80, flows out from a gas discharge port 82, and sent to a related plant apparatus. Is extracted, and impurities in the gas are removed by the filters 84 and 85 and supplied to the seal gas inlet 54 of the dry gas seal unit 100.
[0024]
The supplied gas passes between the stationary side seal member and the rotary side seal member in the dry gas seal portion 100 as described in the conventional example, and the gas supplied to the gas seal is supplied from the seal gas outlet 55. It is supplied to the inlet 11 of the small cyclone separator 1 provided in parallel through the flow meter 65 and through the on-off valves 2 and 3. The two cyclonic separators 1 may be operated in parallel or by switching only one of them, and the cyclonic separator 1 is included in the gas by giving a swirl flow to the supplied gas as will be described later. Carbon and foreign substances are removed and discharged as flare from the upper outlet 12 via the on-off valves 4 and 5.
[0025]
FIG. 2 is a cross-sectional view showing the details of the cyclonic separator 1 described above, and relates to the first embodiment of the present invention. In the figure, the cyclonic separator 1 has a two-part structure of an upper container 15 and a lower container 16, is connected by a connecting portion 17, can be divided as needed, and is made of a transparent material, and the inside is visually confirmed. It is a possible structure. A hopper 14 is provided inside, and a filter 18 is detachably provided below the hopper 14.
[0026]
In the cyclone separator 1 described above, the gas flowing in from the inlet 11 swirls in the hopper 14, and if the gas contains foreign matter such as carbon or dust caused by wear of the seal portion, the foreign matter 90 is swung. It falls to the lower part and deposits on the lower filter 18. The gas separated from the foreign matter 90 flows out from the upper outlet 12, and the gas that has passed through the filter 18 also flows out from the upper outlet 12.
[0027]
When the foreign matter 90 separated by the cyclone separator 1 is periodically observed from outside the transparent container every predetermined time, and the state of foreign matter mixing in the gas is extremely deteriorated, that is, this situation Can be determined visually. Further, when it is difficult to grasp the situation by observation from the outside, or even in a steady state, the upper container 15 and the lower container 16 are periodically separated, the internal filter 18 is removed, and the foreign matter 90 accumulated on the filter 18 is removed. The state can be directly visually confirmed, and the soundness of the dry gas seal unit 100 can be evaluated from the state of the foreign matter.
[0028]
FIG. 3 is a system diagram of an apparatus for performing the dry gas seal soundness management method according to the second embodiment of the present invention. In the second embodiment, the foreign matter 90 separated by the cyclone separator 1 and deposited on the filter 18 is automatically observed. For this purpose, the foreign matter on the filter 18 of the cyclone separator 1 is removed. A camera 20 for photographing from outside the container is installed.
[0029]
The image of the foreign object 90 photographed by the camera 20 is guided to the image processing device 21 and binarized to capture the shape of the foreign material, and the shape information is guided to the automatic determination device 22. The automatic determination device 22 sets and stores characteristic data of an image of a foreign matter accumulation pattern on the normal filter 18 after operation for a predetermined operation time and a kind of foreign matter (carbon, dust, etc.). The set data and the image of the foreign object 90 photographed by the camera 20 are compared, the type and amount of the foreign object are grasped, the degree of soundness of the gas seal is determined, and the result is displayed on the display device 23.
[0030]
According to the second embodiment as described above, in the first embodiment, since the operator visually observes and determines the degree of soundness of the dry gas seal, it is automatically determined. By the objective determination of the degree of soundness, the dry gas seal portion 100 of the compressor can be systematically stopped for repair and inspection. Further, such a determination can be performed at an arbitrary time during operation of the plant.
[0031]
FIG. 4 is a system diagram of an apparatus for implementing the dry gas seal soundness management method according to the third embodiment of the present invention. Also in the third embodiment, the soundness of the dry gas seal is automatically determined, but the foreign matter 90 accumulated on the filter 18 is taken out of the container and the weight, etc. are automatically measured. .
[0032]
In FIG. 4, reference numeral 30 denotes a suction port that sucks and takes out the foreign matter 90 on the filter 18 out of the container of the cyclonic separator 1. 31a and 31b are pipes, 32 is a suction device, 33 is an automatic measuring device, and automatically measures the weight of the foreign matter 90 sucked by the suction device 32. Reference numeral 34 denotes a display device, which displays the result measured by the automatic measuring device 33. A control device 35 controls the operation of the suction device 32 and the automatic measuring device and the opening / closing of the on-off valves 2, 3, 4, and 5.
[0033]
In the third embodiment of the above configuration, the control device 35 closes the opening / closing valve of only the cyclonic separator 1 among the opening / closing valves 2, 4, 3 and 5 of the cyclonic separator to be measured, and measures one of them. State, and let the gas pass through the other to be in the operating state. Next, the suction device 32 is controlled to suck the foreign matter 90 accumulated on the filter 18 from the piping of the suction port 30 to be measured. The weight of the sucked foreign matter 90 is measured by the automatic measuring device 33, and the result is displayed on the display device 34. Therefore, the operator monitors the result and the state of soundness and deterioration during the operation of the dry gas seal. Etc. can be judged.
[0034]
In the first embodiment described above, the foreign matter 90 is separated by a cyclone separator, the foreign matter 90 deposited on the filter 18 is visually observed, the type and amount of carbon and dust are identified, In the second embodiment, the camera 20 captures the foreign matter on the filter 18 in the container, the image is processed by the image processing device 21, and the automatic determination device 22 performs the determination and quantitative grasp of the carbon and dust. In the third embodiment, the foreign matter 90 on the filter 18 is sucked by the suction device 32, and the weight is measured and displayed by the automatic measuring device 33 so that each operator can check whether the dry gas seal is healthy. The sex is determined from the information.
[0035]
The operator determines the dry gas seal by performing the above measurement several times every predetermined time, plotting the results in time series, and measuring the rate of increase in the weight of foreign matter, ie, carbon, etc. of these measured values. Etc., extending this increasing trend and predicting it, comparing the value with a preset reference value, alarm generation level value, trip value, and predicting the life of the dry gas seal part 100, This is a method that the operator predicts based on the measured data.
[0036]
FIG. 5 is a system diagram of an apparatus for implementing the dry gas seal soundness management method according to the fourth embodiment of the present invention. In the figure, the process gas flows into the dry gas seal portion 100 of the compressor 80 into the seal gas inlet 54, and the gas after the sealing action flows out from the seal gas outlet 55. A total of 65 is provided.
[0037]
The signals detected by the flow meter 65 and the pressure gauge 40 are converted into digital signals by the A / D converters 41 and 42, respectively, and input to the arithmetic unit 43. In the arithmetic unit 43, as will be described later, an approximate curve of a change in the gas leak amount or pressure value with the passage of time of the dry gas seal is obtained, and from the measured value measured at an arbitrary time on the basis of the approximate curve. The soundness of the dry gas seal during the operation is determined. The storage device 44 stores the approximate curve data obtained by the arithmetic device 43, and the display device 45 displays the determination result calculated by the arithmetic device 43.
[0038]
In the fourth embodiment of the above configuration, the arithmetic device 43 first takes in past operation data of the dry gas seal unit 100 and stores it in the storage device 44, and the primary leak with the passage of time of the dry gas seal unit 100. The amount or pressure value is accumulated every time, and based on these data, an approximate curve of the gas leak amount or pressure until the primary leak amount or pressure value to be tripped by the compressor is obtained, and these data are stored. It is stored in the device 44.
[0039]
The storage device 44 is preliminarily set with a primary leak amount or pressure guarantee value, reference value, alarm value, and trip value of the compressor 80. The guaranteed value is the guaranteed primary leak amount or pressure determined by design, the reference value is guaranteed value x 1.8 times, the alarm value is guaranteed value x 4 times, and the trip value is guaranteed value x 8 times. These set values are used to generate an alarm when the primary leak amount or pressure of the dry gas seal during operation exceeds the reference value and become an alarm value, and to trip the compressor when the trip value is reached.
[0040]
The arithmetic device 43 takes in data from the flow meter 65 and the pressure gauge 40 several times at a predetermined time interval at any time during the operation of the compressor, and based on these measured values, the least square method or the like. Using the mathematical method, the primary leak amount or the rate of increase of the pressure value is obtained, and the characteristic curve during operation until the trip value set in advance is estimated and calculated.
[0041]
The arithmetic device 43 also compares the approximate curve data stored in the storage device 44 with the characteristic curve during operation accumulated from the measured values. First, the time from the approximate curve to the time when the compressor trips is calculated. , And this is displayed on the display device 45, and the operator can systematically stop the plant based on this result by monitoring this, so the preparation for that is planned in advance be able to.
[0042]
Further, the arithmetic unit 43 compares the characteristic curve estimated during operation with the approximate curve stored in advance, and if the time to the trip value exceeds a predetermined error ± α (%), an alarm is generated. The display is displayed on the display device 45 to inform the operator that dust or the like excessively enters the dry gas seal portion 100 of the compressor to cause an abnormal state. Of course, when the primary leak amount or pressure exceeds a preset alarm value at or near the present time, an alarm is displayed. Accordingly, an abnormal primary leak amount or pressure rise that is different from the steady state of the dry gas seal portion 100 can be detected at an early stage, and a serious accident can be prevented in advance.
[0043]
FIG. 6 is a graph showing the contents implemented by the arithmetic unit 43 according to the fourth embodiment of the present invention. In the figure, the vertical axis represents the primary leak amount or pressure, and the horizontal axis represents time. A curve S ₀ is an approximate curve serving as a reference obtained from past driving performance data, and is stored in the storage device 44. D ₁ is a guaranteed value, D ₂ is a reference value, D ₃ is an alarm value, and D ₄ is a trip value, which are preset and stored in the storage device 44. S ₁ and S ₂ are estimated characteristic curves during operation, and are the results of obtaining the rate of increase from the measured values at times t ₁ , t ₂ and t ₃ by a mathematical method such as the least square method.
[0044]
α is a range of error from time t ₄ to reach the trip value D ₄ determined by S ₀ , and if the error of the curve estimated by S ₁ and S ₂ is within this range, the dry gas seal portion is stationary. since slide into degraded state, the time to trip the compressor is determined as being substantially determined by the approximate curve of S _0. If the error exceeds this range α, it is determined that there is a high possibility that a serious accident such as contact will occur due to the intrusion of dust or the like into the dry gas seal at the present time. In the example shown in the figure, the errors of the trip value D ₄ are α ₁ and α ₂ for both S ₁ and S ₂ , which are smaller than α, and thus are determined to be normal.
[0045]
Further, the carbon amount and the like gradually increase due to the deterioration of the dry gas seal portion in the normal state from the current time t _3, and the time for which the compressor is tripped for repairing and mounting the parts is the approximate curve S ₀ . The time t ₄ is known from the trip value D ₄ which is the set value, and the time after the T time is predicted as the trip time. During this time, you are ready for a planned plant shutdown. In addition, when the error in the time to reach the trip value is abnormally large, it can be determined to make an emergency stop in advance after several hours.
[0046]
【The invention's effect】
The dry gas seal soundness management method of the present invention is as follows: (1) Among the actual data of the gas leak amount from the dry gas seal portion of the compressor, the gas leak to be tripped from the time of the data exceeding the reference value An approximate curve of the amount of gas leak up to the amount of time is estimated by plotting the trend of the actual data; the amount of gas leak at an arbitrary time interval during the operation of the compressor is detected by several means. Measuring; comparing the measured values of the same number of points with the approximate curve, and estimating the arrival time from the time of measurement during the operation to the trip of the compressor from the trip time of the approximate curve It ’s the right way. The amount of gas leak occurs due to wear at the dry gas seal portion and is proportional to the amount of carbon contained in the gas. Therefore, the above method is carried out by measuring the amount of foreign matter such as carbon. For that purpose, a cyclone separator is used to separate foreign substances from the gas and this amount is measured.
Conventionally, when such a method is used, the operator measures and reads the leak amount each time and determines whether to continue the operation based on experience each time. Is determined in advance, and the planned compressor shutdown can be performed. Moreover, the preparation for the stop of the related plant for that purpose can also be made systematically, and the reliability of not only the compressor but the operation of the whole plant is improved.
[0047]
In ( 2 ) of the present invention , the separation container is made transparent, and the amount of foreign matter is measured from the outside of the container with a camera. In ( 3 ), the amount of foreign matter is sucked out of the container, and the amount This makes it easy to measure the amount of gas leak.
[Brief description of the drawings]
FIG. 1 is a system diagram of an apparatus to which a dry gas seal soundness management method according to first to third embodiments of the present invention is applied.
2 is a cross-sectional view of a cyclonic separator used in the apparatus of FIG. 1 according to the first embodiment of the present invention.
3 is a cross-sectional view of a cyclonic separator used in the apparatus of FIG. 1 according to a second embodiment of the present invention and a configuration diagram of a determination apparatus thereof.
4 is a cross-sectional view of a cyclone separator used in the apparatus of FIG. 1 according to a third embodiment of the present invention and a configuration diagram of the determination apparatus.
FIG. 5 is a block diagram of an apparatus to which a dry gas seal soundness management method according to a fourth embodiment of the present invention is applied.
FIG. 6 is a diagram showing the principle of a dry gas seal soundness management method according to a fourth embodiment of the present invention.
FIG. 7 is a general cross-sectional view showing a dry gas seal portion of a compressor and a configuration diagram of an apparatus for tripping a conventional compressor.
8 is a detailed system diagram of the conventional trip device shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cyclone-type separator 2, 3, 4, 5 On-off valve 11 Inlet 12, 13 Outlet 14 Hopper 15 Upper container 16 Lower container 17 Connection part 18 Filter 20 Camera 21 Image processing apparatus 22 Automatic determination apparatus 23, 34, 45 Display apparatus 30 Suction port 32 Suction device 33 Automatic measuring device 35 Control device 40 Pressure gauge 41, 42 A / D converter 43 Arithmetic device 44 Storage device

Claims (3)

Of the actual data on the amount of gas leak from the dry gas seal of the compressor, an approximate curve of the amount of gas leak from the time of the data exceeding the reference value to the time of the gas leak amount that should trip the compressor is the above result Estimate it by plotting the trend of the data; measure several points of gas leak at any time interval during compressor operation by the detection means; compare the measured value of the same number with the approximate curve The dry gas seal soundness management method for estimating the arrival time from the measurement time during the operation to the trip of the compressor from the trip time of the approximate curve, wherein the gas leak amount is a cyclone type health management method of de Rye gas seal you and estimates the amount of foreign matter such as carbon contained in the gas separated in the separator. The container of the cyclonic separator is a transparent container, and the amount of gas leak is estimated from an image of the foreign matter by photographing the foreign matter accumulated in the lower part of the separator with a camera from outside the container. The method for managing the soundness of a dry gas seal according to 1 . The foreign matter according to claim 1 health management method of dry gas seal, wherein the extraction by suction by the suction device to the outside of the container of the cyclone separator, is measured.

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