Compressor Performance

Size: px

Start display at page:

Download "Compressor Performance"

Dale Page
8 years ago
Views:

1 expertise beyond controls Compressor Performance Advisor (CPA) Software

2 Monitoring compressor performance for the purpose of evaluating compressor productivity and optimizing maintenance intervals is an important part of the gas-compression industry. It is common practice to measure inlet and discharge pressures, temperatures, mass flow rate, and speed for compressor performance evaluation. CPA also takes into account a variable gas composition.

It is common practice to measure inlet and discharge pressures, temperatures, mass flow rate,

3 As with most mechanical devices, the performance of a running compressor slowly deteriorates from its normal healthy condition. For example, if a compressor operates at a constant compression ratio, blade fouling will decrease the flow rate and efficiency at any operational speed. CPA quantifies this degradation by comparing runtime performance to a calculated baseline model representing healthy compressor conditions. CPA uses unique real-time software which can be adapted to any compressor. This model is normally built from performance data provided by the compressor original equipment manufacturer (OEM). When OEM data is not available, CPA requires on-site performance test data to build the model. This compressor performance testing should generally performed by a CCC field engineer All compressor performance calculations are normalized for the steady state operational mode using a BWRS real gas equation of state (EOS), in compliance with the ASME PTC-10 standard. The main CPA functionality includes: u Creating compressor performance mathematical models using the normalized process parameters and basic gas composition u Calculating, monitoring and recording productivity and efficiency as runtime compressor performance parameters u Tracking the deviation of compressor performance parameters from the modeled healthy conditions and alarming if the deviation exceeds a threshold u Showing compressor performance deviation trends to recognize existing problems and predict developing ones u Providing runtime transmitter verification and alarming CPA is easily integrated with CCC human-machine interface (HMI), providing a plant operator with: u Compressor maintenance recommendations for minimizing compressor downtime and extending compressor lifecycle u Compressor runtime performance data for optimizing compressor efficiency by adjusting operational conditions Performance Monitoring For compressor performance monitoring, CPA creates mathematical models of the compression ratio, head, efficiency, and power as functions of the flow, speed, and gas composition for the whole range of the compressor operational conditions: u R c = f (Qs, N) u ηp = f (Qs, N) u H p = f (Qs, N) optional u J = f (Qs, N) optional The model curves are built for healthy compressor conditions using OEM or performance test data. An operator can see measured parameters together with calculated parameters on the CPA monitoring screen. Using the following runtime data from a control system, CPA calculates operating points that represent the actual compression ratio, volumetric flow in suction, speed, polytrophic head, efficiency, and compression power. u Flow measurement at suction or discharge u Suction and discharge pressures and temperatures u Rotation speed u Gas composition The CPA monitoring screen displays the realtime performance values and bar graphs, indicating their deviations against the modeled healthy conditions. If the process permits, an operator can optimize compressor operation by adjusting the flow or pressure set point that moves the CPA operating point to maximum compressor efficiency.

CPA quantifies this degradation by comparing runtime performance to a calculated baseline model representing healthy compressor conditions.

4 Performance Degradation The compressor performance deterioration trends are displayed on the CPA performance degradation screen. An operator can see the historical deviation of the compressor Hp, Rc, power, and efficiency from the healthy conditions. CPA will predict the development of deterioration based on the historical performance degradation rate. The predicted compressor deterioration is shown as a dotted line on the performance degradation screen to help an operator make compressor maintenance decisions. Alarms will be generated if: u Compressor performance degradation exceeds the configured threshold u Predicted performance degradation exceeds the configured threshold Compressor Performance Test Sometimes compressor performance OEM data is not availabl,e or actual compressor performance significantly deviates from the OEM data. In both cases, a performance test is required to collect performance data and build a compressor model for healthy conditions. It is recommended that a qualified CCC engineer run the performance test after compressor maintenance is completed. Compressor Map Invariant to Gas Composition For more information about our Compressor Performance Advisor software and other state-of-the-art products from the world leader in turbomachinery control, please contact a CCC office near you. We are uniquely qualified to solve turbomachinery control problems, and we will help you achieve maximum turbomachinery performance regardless of your equipment or process. Some high-technology processes deal with variable gas compositions when the gas compressibility periodically changes. CPA uses gas composition data updated by an operator for calculating actual compressor performance. CPA generates performance curves for a compressor map and dynamically recalculates the curves to reflect the current gas composition or changing suction conditions.

CPA will predict the development of deterioration based on the historical performance degradation rate.

5 Transmitter Verification CPA analyzes real-time data from controller (Ps, Pd, Ts, Td and N) for transmitter verification. The following alarms are provided in case the real-time parameter relations do not match the values calculated by the model: u Transmitter overestimate Ps or understating Pd u Transmitter overestimate Pd or understating Ps u Transmitter overestimate Ts or understating Td Remote Operator Station CPA provides an operator with remote compressor performance monitoring. The performance monitoring and performance degradation screens can be shown on a remote operator station connected to a CCC server. u Transmitter overestimate Td or understating Ts Gas Compositions Supported in CPA 1. Ammonia 2. Benzene 3. Butane 4. Carbon dioxide 5. Carbon monoxide 6. Decane 7. Ethane 8. Ethylene 9. Helium 10. Heptane 11. Hexane 12. Hydrogen 13. Hydrogen sulphide 14. Isobutylene 15. Isobutane 16. Isopentane 17. Methane 18. Methyl Chloride (Chloromethane) 19. Nitrogen 20. Nonane 21. Octane 22. Oxygen 23. Pentane 24. Propylene 25. Propane 26. Water vapor Field-Proven Operation CPA incorporates compressor modeling that was developed and fine-tuned over the course of more than eight years of field operation in more than 50 CCC performance diagnostics system (PDS) installations worldwide. CPA provides a plant operator with: u Compressor maintenance recommendations for minimizing compressor downtime and extending the compressor lifecycle u Compressor runtime performance data for optimizing compressor efficiency by adjusting operational conditions

overestimate Pd or understating Ps u Transmitter overestimate Ts or understating Td Remote Operator Station CPA provides an operator with remote compressor performance monitoring.

6 Global experience. Global support. Australia / Saudi Arabia / Brazil / China / India / Italy / Netherlands / Russia Singapore / U.A.E. / United Kingdom / United States Contact your local sales representative. Please visit our website: Compressor Controls Corporation CPA 09/12

Fluid & Gas Properties

Fluid & Gas Properties FLUID DENSITY Density is the ratio of mass to volume. In English, units density is expressed in pounds mass/cubic foot (lbm/ft 3 ). The symbol for density is ρ. Density is usually