Benefits of model based analysis
The need to reduce operating costs are resulting in new technologies mathematically modelling the whole of the compression system. Techniques such as Component Matching can model a compression system under any steady state operating conditions. This includes the process as well as the gas turbine drivers, which are often used for mechanical drive applications. These models are capable of including side streams and third party gas. GasComp is a program which uses the Component matching technique to model the steady state performance of any gas compression system.
With such models plant optimisation is possible. An exhaustive search technique may be attached to the model and the modelling system is then able to determine set points for the control system in order to minimise fuel consumption. These models may also be applicable to electric motor driven compressors.
A series parallel compression system producing 300MMSCFD. Note that the LP and HP1 compressors are in recycle. The fuel consumption was 12.41 MMSCFD.
After optimisation the compressors are outside recycle, and fuel consumption is 11.5 MMSCFD. This represents over 7% reduction in fuel consumption
When GasComp is used with the performance monitoring system they give rise to concepts such as production-based maintenance. Process equipment and gas turbine component faults resulting in reduced production can be implanted into the model using GasComp. The increased revenue can be compared with the maintenance cost incurred to fix any problems to determine the return on the maintenance investment. If this is favourable maintenance activity may be planned.
GasComp can also be used for predictive based maintenance. A known production profile is run using GasComp. Ambient conditions may be taken from historical data. At the end of the profile the system can calculate creep life used. This information can be used in scheduling overhauls.