Sampled compressor model
The compressor model is set up in an external tool, and this model is sampled by
running a point set of rates and pressures which span the operational area of the compressor train. The sampled data (rates, inlet pressures, outlet pressures and total energy usage for all stages) are specified in a .csv file and
inputted into eCalc™. Each line in the .csv defines a point (rate, suction pressure, discharge pressure) and the total energy usage.
-
For electrically driven compressor trains. The total energy usage should be given in megawatts (MW).
-
For turbine driven compressor trains. It is recommended to give the total energy usage in megawatts (MW) and couple the compressor model to a turbine model. However, it is possible (for backward compatibility) to give the total energy usage as fuel usage in standard cubic meters per day (Sm3/day) and use the model directly. In this case, you can also provide a POWER (MW) column to calculate power for the shaft based on fuel usage.
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The latter (turbine driven compressor train) will at some point become deprecated as it is replaced by COMPRESSOR_WITH_TURBINE mentioned above.*
-
Inside the convex hull defined by the input variables, there is a
barycentric interpolationbased on aDelaunay triangulation. -
Outside the defined area, there may be extrapolations where this is reasonable, i.e.,
- for rates lower than the defined rates, the table is extrapolated up to minimum flow (to mimic ASV (anti-surge valve)/recirculation valve)
- the suction pressure is extrapolated down to the defined area
- the discharge pressure is extrapolated up to defined area to mimic choking when the required head is lower than the compressor operational area.
Format
The sampled compressor model is defined under the main keyword FACILITY_INPUTS in the format
NAME: <model name>
FILE: <sampled_data>.csv
TYPE: COMPRESSOR_TABULAR
Header requirements for the sampled compressor csv file
POWER(and/orFUEL)- A minimum of one (but more are allowed) of the following:
RATESUCTION_PRESSUREDISCHARGE_PRESSURE
In cases where the model is directly used as a turbine/fuel driven compressor without coupling it to an eCalc turbine
model, POWER may be replaced by FUEL.
In the case FUEL is provided, it is also possible to specify POWER in the csv-file in order to calculate shaft power usage for fuel driven compressors
If only POWER is provided, we assume that the compressor is electrical-driven
If FUEL is provided, we assume that the compressor is turbine-driven (also when both FUEL and POWER is given)
Units
| Quantity | Units |
|---|---|
POWER | MW |
RATE | Sm3/day |
SUCTION_PRESSURE | bar |
DISCHARGE_PRESSURE | bar |
FUEL | Sm3/day |
Example tables
1D example
| RATE | POWER |
|---|---|
| 0 | 0 |
| 100000 | 10 |
| 1000000 | 10 |
| 2600000 | 15 |
| 4400000 | 20 |
3D example
| RATE | SUCTION_PRESSURE | DISCHARGE_PRESSURE | POWER |
|---|---|---|---|
| 1.00E+06 | 10 | 12.72 | 0.3664 |
| 1.00E+06 | 10 | 26.21 | 2.293 |
| 1.00E+06 | 26 | 31.36 | 0.2739 |
| 1.00E+06 | 26 | 70.77 | 6.28 |
| 1.00E+06 | 34 | 41.21 | 0.368 |
| 1.00E+06 | 34 | 94.24 | 8.435 |
| 1.00E+06 | 78 | 94.12 | 0.7401 |
| 1.00E+06 | 78 | 231.6 | 22.46 |
| 6.00E+06 | 26 | 36.93 | 4.197 |
| 6.00E+06 | 26 | 57.43 | 7.32 |
| 6.00E+06 | 38 | 46.96 | 2.156 |
| 6.00E+06 | 38 | 106.2 | 9.557 |
| 6.00E+06 | 54 | 67.26 | 1.95 |
| 6.00E+06 | 54 | 155.6 | 14.35 |
| 6.00E+06 | 78 | 94.17 | 1.399 |
| 6.00E+06 | 78 | 231.6 | 22.46 |
| 1.10E+07 | 42 | 66.92 | 9.712 |
| 1.10E+07 | 42 | 81.63 | 11.89 |
| 1.10E+07 | 62 | 75.64 | 3.678 |
| 1.10E+07 | 62 | 180.8 | 16.94 |
| 1.10E+07 | 78 | 97.79 | 3.452 |
| 1.10E+07 | 78 | 231.6 | 22.46 |