Process components

All separators are simulated without pressure loss and the only user specified value based on measurements is the pressure of the inlet stream. A separator is shown in Figure 4.5.

Figure 4.5 A separator with an inlet stream, a vapor stream, a liquid stream and a water stream

All scrubbers are simulated without pressure loss. Pressure and temperature of the inlet stream are specified for all scrubbers, except the import gas scrubber, VG-23-0006, where no variables are specified. A scrubber is shown in Figure 4.6.

Figure 4.6 A scrubber with an inlet stream, a vapor stream and a liquid stream

All mixers set the outlet pressure equal to the lowest inlet pressure. A mixer is shown in Figure 4.7.

Figure 4.7 A mixer with two inlet streams and one outlet stream

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The important parameter of a tee is the splits of the flow ratios. Most split flow ratios are not specified, but based on specified flow of the corresponding streams. For the tees PROD_DIV and FUEL2 the split flow ratio is specified based on the engineering manuals of the platform. The split flow ratio of FUEL1 is manually adjusted to fit the measured flow out of the superheater FE-45-0002A/B. For TEE-Turbine the split ratio is based on the flows to CT-23-0001 and CT-80-0001A in 2012. Due to lack of information the split flow ratios in the water distribution system is assumed to be 50/50 for all tees. A tee is shown in Figure 4.8.

Figure 4.8 A tee with one inlet stream and two outlet streams

The valves can be divided into five categories; valves at the liquid stream out of the scrubbers, valves at the recycle stream of the compressors, valves related to separators, valves in the manifolds and other valves. The pressures after the valves at the liquid streams out of the scrubbers VG-23-0002/6, are set equal to the pressure of the inlet stream of the first separator, VA-20-0001. The valve at the liquid stream out of the scrubber VG-23-0001 is assumed to have no pressure drop, and the valve related to VG-23-0002 is assumed to have an outlet pressure of 5 bar. The valves related to the recycle stream of the compressors have an outlet pressure equal to the lowest pressure at the inlet of the related mixer, see Figure 4.17. The exception is the valve related to the import gas compressor where the pressure is set in a way that the pressure at the inlet of the scrubber is equal to the measured value. The valves related to the separators decrease the pressure down to the specified pressure of the upcoming separator. The valves in the wells have specified values for both inlet and outlet pressure, and the valves in the manifolds reduces the pressure down to the inlet pressure of the corresponding separator. The valve PV-45-0103 decreases the pressure of the fuel gas stream down to the specified inlet pressure of the fuel gas scrubber, VG-45-0001. A valve is shown in Figure 4.9.

Figure 4.9 A valve with an inlet stream and an outlet stream

All compressors have specified outlet pressure and temperature. The inlet condition is calculated based on the inlet conditions of the corresponding scrubber. The exception is the import gas compressor which has measured values for inlet pressure and temperature. A compressor is shown in Figure 4.10.

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Figure 4.10 A compressor with an inlet and an outlet stream and a power stream

The coolers have no specified values. The related heaters has specified pressure drop from the components datasheet. The heater is just for calculation purpose. A cooler with its related heater is shown in Figure 4.11.

Figure 4.11 A cooler with an inlet and an outlet stream It is connected to a heater for calculation purpose.

The heaters have specified pressure drop from the components datasheet, the exception is the electrical superheater FE-45-0002A/B where both inlet and outlet pressure are specified. The cooler is just for calculation purpose. A heater with its related cooler is shown in Figure 4.12.

Figure 4.12 A heater with an inlet and an outlet stream It is connected to a cooler for calculation purpose.

The heat exchangers have specified pressure drop, both on shell side and tube side. The oil/water heat exchanger, HB-20-0002, has also specified UA-value form datasheet, called UA service value. A heat exchanger is shown in Figure 4.13.

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Figure 4.13 A heat exchanger

The heat exchanger has one inlet and one outlet stream at the tube side, and one inlet and one outlet stream at the shell side.

Nearly all pumps have a specified adiabatic efficiency; this is found in the pumps performance curves.

The exception is PG-20-0001A/B/C/D, PG-20-0001E and the pumps in the produced water injection, which uses the default value of 75 % adiabatic efficiency. The dummy pump, which only is included for simulation purposes in order to secure no vapor phase out of the coalescer, has a specified adiabatic efficiency of 100% and a specified duty that is as low as possible. A pump is shown in Figure 4.14.

Figure 4.14 A pump with an inlet and outlet stream and a power stream

The pipes are used to simulate the pressure loss in the long pipes in the seawater and hot water distribution. Both the inlet and the outlet stream have specified/calculated pressures, so the only specification of the pipes is an assumed geometry. A pipe is shown in Figure 4.15.

Figure 4.15 A pipe with an inlet and an outlet stream and a heat stream

The turbines GG Compressor and GG Turbine have assumed adiabatic efficiencies of 75 % and 90 %, respectively. The temperature of the surroundings is assumed to be the measured value of the surrounding air for CT-80-0001A. The GG Compressor has a pressure ratio of 23 according to user manuals. The temperature after the combustion is assumed to be 1350 °C and is achieved by

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adjusting the mass flow of air. The power out of the Power Turbine is specified based on

measurements for the generator drive turbines and for the mechanical drive turbine the thermal efficiency is assumed to be 41 %. Generator efficiency is neglected. Since the reaction stoichiometry is not known, the reactor type “Gibbs Reactions Only” is chosen. The Gibbs reactor is assumed to have no pressure drop; thereby the outlet pressure is equal to the air inlet pressure. A figure of the turbine unit can be seen in Section 3.2.2.3 or in Appendix K.