XPLORE – Calculation Modules: Compression
The Xodus Compression Module utilises operational data, custom calculations, industry standard calculations and advanced simulation technology to provide a state of the art monitoring system analysing all aspects of compressor operation and maintenance.
Each system is custom designed utilising the required functionality from the following list:
› Online real-time visualisation
› Molecular weight reconciliation
› Fixed or variable speed drives
› Thermodynamic calculations
› Mechanical degradation monitoring
› Real time/ historical, predictive and ‘what if’ operating modes.
Online Real-Time Visualisation
The Compression Calculation Module gives the user the ability to view a large amount of system data and complex calculated information in real-time. Such information is normally only available following offline studies. Typical plots available to the user are Operating Point -v- Design Curves for Polytropic Head, Efficiency & Power -v- Flow. Head can be viewed as Head, DeltaP, Compression Ratio or Discharge Pressure. Flow can be viewed as Actual or Standard Flow. Plots can show Control lines (for example the CCC control lines SCL, SLL, SOL, RTL can be viewed).
Molecular Weight Reconciliation
Composition can be obtained online if available, otherwise it can be manually entered periodically and Molecular Weight reconciliation performed over time.
Fixed or Variable Speed Drives
The module has the ability to handle fixed or variable speed drives including all available speed, efficiency and power curve data.
All such complex calculations are performed online in real-time, are available through the user interface and can be trended. For compressor monitoring we recommend and utilise Multiflash. Multiflash gives us access to a vast number of thermodynamic methods allowing us to analyse each system and select the most appropriate method.
Mechanical Degradation Monitoring
With the help of the performance monitoring system the performance degradation and fouling of the compressor unit can be evaluated and monitored. It is essential to detect degradation before corrective action can be started. Real time condition monitoring is an important part of modern and efficient management of industrial flow machines. Compressor performance is calculated by monitoring certain parameters of the compressor, e.g. efficiency or the required shaft power of the compressor. In order to reliably monitor performance, condition monitoring system has to produce a reference value against which the real operating value can be compared. Usually the reference value is selected so that it represents the reference value of a new compressor.
Real time / Historical, Predictive and ‘What If’ Modes
The system can operate in any one of three modes. Real time operation shows the current status of the compressor. All of the measured and calculated data is saved to a historical database therefore the user can go back in time and review historical operation.The system can include the ability to run
in predictive mode so that in addition to real-time information the user also has information regarding the operation of the compressor in the near future. Depending on the complexity of the model we can predict up to 36 hours into the future.
In ‘what if’ mode the user can freeze the system and change any of the input parameters, for example the gas composition, and review what happens to the compressor operation. In this mode the real time data is stored in the background and refreshed when real time mode is reselected.
A typical architecture for a compression monitoring system includes the standard XPLORE framework linking to the customer’s data historian. The compression module along with custom calculations and information from the Multiflash package supply the user via a web server with real-time and historical (and if required predictive and ‘what if’) information regarding the operation of their compressor or whole compression system.