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CN-122014661-A - Dynamic safety margin anti-surge control system and method for MVR (mechanical vapor recompression) steam compressor

CN122014661ACN 122014661 ACN122014661 ACN 122014661ACN-122014661-A

Abstract

The invention discloses a dynamic safety margin anti-surge control system and method for an MVR (mechanical vapor recompression) steam compressor, and relates to the technical field of safety control of fluid machinery. The method comprises the following steps of parameter acquisition, boundary calculation, margin adjustment, control line generation and prevention and control execution. The invention can predict and intervene the surge occurrence, ensure the efficient and safe operation of the compressor, adapt to the operation characteristics of the MVR system, automatically adjust the control strategy, and has convenient operation and visual maintenance.

Inventors

  • HUANG GUANGMING

Assignees

  • 中国轻工业长沙工程有限公司

Dates

Publication Date
20260512
Application Date
20260404

Claims (10)

  1. 1. The dynamic safety margin anti-surge control system of the MVR vapor compression machine is characterized by comprising a sensor group, an anti-surge valve and a controller; the sensor group comprises a flow sensor, a pressure sensor, a temperature sensor and a rotating speed sensor, and the sensor group detects the running parameters of the compressor in real time and transmits the running parameters to the controller; The anti-surge valve is arranged on a return pipeline from the outlet to the inlet of the compressor, an opening feedback assembly is configured, and the opening feedback assembly returns a real-time opening signal to the controller to form an opening closed-loop regulating circuit; The controller is connected with the sensor group and the anti-surge valve through electrical signals respectively, and is a hardware module with data analysis, operation processing and instruction output.
  2. 2. The MVR vapor compressor dynamic safety margin anti-surge control system of claim 1, further comprising a human-computer interaction interface, wherein the human-computer interaction interface is an interaction component, wherein the human-computer interaction interface is electrically connected with the controller, the operating point, the surge boundary line, the anti-surge control line, the dynamic safety margin and the early warning information are displayed in real time, and the human-computer interaction interface is configured with a manual intervention interface.
  3. 3. A method of dynamic safety margin anti-surge control for an MVR vapor compression compressor adapted to the system of claim 1 or 2, comprising the steps of: s1, collecting parameters, namely collecting operation parameters of a compressor in real time to determine real-time operation working condition points, and transmitting the collected operation parameters to a controller in a digital signal form; S2, calculating a boundary, namely after the controller receives the transmitted operation parameters of the compressor, calculating a surge boundary line at the current rotating speed in real time according to the design performance data of the compressor, and storing the surge boundary line data into the controller; S3, margin adjustment, namely after the controller receives the transmitted operation parameters of the compressor, setting a dynamic safety margin, adaptively adjusting according to the stable state of the operation working condition of the compressor and the change trend of the operation parameters, and storing the adjusted dynamic safety margin data to the controller; S4, generating a control line, namely calling surge boundary line data and adjusted dynamic safety margin data by the controller, calculating the real-time operation pressure ratio of the anti-surge control line and the compressor under the current working condition, and storing a calculation result to the controller; And S5, performing prevention and control, namely calling the data of the anti-surge control line and the data of the real-time operation pressure ratio of the compressor by the controller, firstly calculating the distance between the real-time operation point and the anti-surge control line, executing early warning operation, continuously comparing the real-time operation pressure ratio with the anti-surge control line in numerical value, judging that the anti-surge valve enters an anti-surge triggering state when the real-time operation pressure ratio is more than or equal to the anti-surge control line, outputting an anti-surge control action signal, calculating the regulating opening of the anti-surge valve, controlling the action of the anti-surge valve, reducing the rotating speed of the compressor, and performing anti-surge control.
  4. 4. The method for controlling dynamic safety margin anti-surge of MVR vapor compressor according to claim 3, wherein in step S1, the operation parameters of the compressor are collected by a sensor group matched with the compressor, the sensor group detects the inlet volume flow, inlet pressure, outlet pressure, rotation speed, inlet temperature and outlet temperature of the compressor in real time, and the collected operation parameters of the compressor are converted into digital signals after analog-digital conversion and are transmitted to the controller.
  5. 5. The method for controlling dynamic safety margin anti-surge of MVR vapor compression machine according to claim 3 or 4, wherein in step S2, the surge boundary line is generated by fitting a surge boundary line fitting formula, the corresponding relation between the inlet volume flow and the pressure ratio is represented, the surge boundary line fitting formula is pi surge =aQ actual 2 +bQ actual +c, pi surge is the surge boundary pressure ratio, Q actual is the inlet volume flow, a, b and c are fitting coefficients, and the fitting coefficients are determined by fitting compressor delivery performance data.
  6. 6. The method for dynamic safety margin anti-surge control of MVR vapor compressor according to any of claims 3 to 5, wherein in step S3, When the compressor runs stably, the controller sets the dynamic safety margin as the basic safety margin, wherein the basic safety margin is the reference safety margin of the compressor running stably, the value range is 5-8%, and the dynamic safety margin is determined by the combination of the factory performance data of the compressor and the process characteristics of the MVR system and is pre-stored in the controller; When the variation rate of the inlet volume flow or the outlet pressure exceeds a preset threshold, the controller adjusts the dynamic safety margin to be a high safety margin with the value range of 10-15%, wherein the preset threshold is a critical judgment value of the variation rate of the inlet volume flow and the variation rate of the outlet pressure, is determined by the process fluctuation characteristic of an MVR system and the operation stability historical data of the compressor and is pre-stored in the controller, and the high safety margin is determined by the combination of the disturbance rejection capability of the compressor and the safety protection requirement of the system and is pre-stored in the controller; When the operation condition is restored to be stable and the duration reaches the preset stability time, the controller controls the dynamic safety margin to gradually decrease at a fixed attenuation rate until the dynamic safety margin is restored to the basic safety margin value, and the preset stability time is the duration judgment duration of the restoration of the steady state of the operation condition, is determined by the process adjustment period of the MVR system and the dynamic response characteristic of the compressor and is prestored in the controller.
  7. 7. The method for controlling dynamic safety margin anti-surge of MVR vapor compressor according to one of claims 3 to 6, wherein in step S4, the controller calculates the real-time operating pressure ratio of the compressor through a real-time operating pressure ratio calculation formula, calculates the anti-surge control line pressure ratio through an anti-surge control line calculation formula, and fits to obtain an anti-surge control line; The calculation formula of the real-time operation pressure ratio is pi actual =P out /P in , wherein pi actual is the real-time operation pressure ratio, P out is the compressor outlet pressure, and P in is the compressor inlet pressure; The calculation formula of the anti-surge control line is pi control =π surge × (1-SM), wherein pi control is the anti-surge control line pressure ratio, SM is the dynamic safety margin, and pi surge is the surge boundary pressure ratio.
  8. 8. The MVR vapor compressor dynamic safety margin anti-surge control method according to one of claims 3 to 7, wherein in step S5, a first early warning threshold and a second early warning threshold are pre-stored by a controller, the two types of thresholds are respectively determined by combining the surge boundary characteristics of the compressor and the response speed of the system, the second early warning threshold is smaller than the first early warning threshold, the controller calculates the distance between a real-time operating point and an anti-surge control line through an early warning distance calculation formula, the early warning distance calculation formula is D=pi control -π actual , wherein D is the distance between the real-time operating point and the anti-surge control line, pi actual is the real-time operating pressure ratio, pi control is the anti-surge control line pressure ratio, when the distance is larger than or equal to the first early warning threshold, the controller does not output an early warning signal and the anti-surge valve does not execute opening action, when the distance is smaller than the first early warning threshold, the controller outputs a high early warning signal and controls the anti-surge valve to open a preset initial opening, the preset initial opening is a fixed opening value pre-stored by the controller, and the preset initial opening is determined by the minimum reflux flow characteristics of the compressor.
  9. 9. The method for controlling dynamic safety margin anti-surge of MVR vapor compressor according to any one of claims 3 to 8, wherein in step S5, the controller calculates the regulating opening of the anti-surge valve by a proportional differential regulating algorithm, wherein the proportional differential regulating algorithm is DeltaV=K p ×(π control -π actual )+K d ×d(π control -π actual )/dt, wherein DeltaV is the increment of the opening of the anti-surge valve, K p is a proportional regulating coefficient, K d is a differential regulating coefficient, K p 、K d is determined by a compressor field characteristic test, pi actual is a real-time operation pressure ratio, pi control is an anti-surge control line pressure ratio, d is a differential operator, and t is a time variable.
  10. 10. The method for controlling dynamic safety margin anti-surge of MVR vapor compressor according to one of claims 3 to 9, wherein in step S5, the anti-surge valve is provided with a fixed maximum opening limit value, the maximum opening limit value is determined by combining a protection limit value of inlet temperature of the compressor and a system reflux characteristic, and when the valve opening reaches the maximum opening limit value and the operation condition does not deviate from a dangerous area, the controller outputs an emergency stop interlocking instruction of the compressor.

Description

Dynamic safety margin anti-surge control system and method for MVR (mechanical vapor recompression) steam compressor Technical Field The invention relates to the technical field of safety control of fluid machinery, in particular to a dynamic safety margin anti-surge control system and method for an MVR (mechanical vapor compression) steam compressor. Background The MVR evaporation system is used as an energy-saving environment-friendly evaporation concentration process, is widely applied to the industrial production fields of chemical industry, food, pharmacy and the like, is a main stream efficient concentration treatment device in the industry, and the vapor compressor is a core power component of the MVR evaporation system, and the running state of the vapor compressor directly relates to the operation continuity and the service life of the whole system. Surging is a common unstable flow fault in the operation process of a steam compressor, when the compressor surges, the internal gas flow and the pressure of the compressor generate severe periodic fluctuation, so that a unit is subjected to strong vibration, long-term or severe surging can directly cause damage to the unit structure such as sealing damage, bearing burning and even rotor breakage, normal propulsion of the production flow is affected, and industrial production has strict requirements on safe and stable operation of the steam compressor. The traditional anti-surge control method mainly comprises a fixed margin method and a single parameter limit control method. The fixed margin method avoids surging by setting a fixed control line far from the surging boundary, but the method has higher safety, but forces the compressor to work in a low-efficiency area for a long time, so that the operation energy consumption is obviously increased. The single parameter control method generally monitors only single parameters such as outlet pressure and takes protection action when the single parameters exceed a set upper limit, and the method has lag reaction, belongs to post-remediation, and cannot avoid the instant impact of surge on a unit. In the MVR evaporation system, because technological parameters such as feed flow, concentration, temperature and the like are frequently changed, fluctuation of operating working conditions of the compressor is large, the existing vapor compressor anti-surge control technology does not realize self-adaptive adjustment of safety margin, only fixed parameters are adopted to perform control, the problem that control is not timely or too conservative easily occurs due to incapability of adapting to the operating scene of the fluctuation of the operating parameters of the MVR system, the prior art lacks a grading early warning mechanism, early warning action and formal anti-surge control are mutually split, progressive protection logic is not formed, forward-looking adjusting capability is not generated, valve opening control does not have accurate adjusting basis, secondary disturbance of the MVR evaporation system is easily caused, the anti-interference capability of the vapor compressor is weak, break points exist in a protection flow, meanwhile, a complete protection system is not built by combining opening limitation and interlocking protection, control response is lag, working condition suitability is poor, continuous and comprehensive anti-surge protection cannot be provided for the MVR vapor compressor, and control requirements of actual production are difficult to meet. Disclosure of Invention The technical problem to be solved by the invention is to overcome the defects in the prior art, and provide the dynamic safety margin anti-surge control system and method for the MVR steam compressor, which can predict and intervene in the surge occurrence, ensure the efficient and safe operation of the compressor, adapt to the operation characteristics of the MVR system, automatically adjust the control strategy, and have convenient operation and visual maintenance. The technical scheme adopted by the invention for solving the technical problems is that the MVR vapor compression compressor dynamic safety margin anti-surge control system comprises a sensor group, an anti-surge valve and a controller; the sensor group comprises a flow sensor, a pressure sensor, a temperature sensor and a rotating speed sensor, and the sensor group detects the running parameters of the compressor in real time and transmits the running parameters to the controller; The anti-surge valve is arranged on a return pipeline from the outlet to the inlet of the compressor, an opening feedback assembly is configured, and the opening feedback assembly returns a real-time opening signal to the controller to form an opening closed-loop regulating circuit; The controller is connected with the sensor group and the anti-surge valve through electrical signals respectively, and is a hardware module with data analysis, operation processing and instruction o