Our Plant

 

Overview

Phase I consists of a conventional thermal power plant with 5x118MW steam turbines, 9×470 t/hr. steam generators, 3xwet limestone Flue Gas Desulphurization (FGD) units and 16×504 m3/hr. Reverse Osmosis (RO) trains. All steam generators and turbines are connected through one common High-High Pressure (HHP) steam header. The steam turbines are backpressure cum condensing units with High Pressure (HP), Medium Pressure (MP) and Low Pressure (LP) steam extractions feeding respective steam headers. In addition, each turbine is supplying steam to a LP feed water heater. To increase operation flexibility and cater for emergency situations, the headers can also be supplied through 100% redundant Pressure Reducing and De-superheating Stations (PRDS).

The steam generators are equipped with individual Electrostatic Precipitators (ESP) downstream the ESPs, the flue gas paths of three boilers are connected, discharging the flue gases to a wet limestone once through Flue Gas Desulphurization (FGD) plant before leaving the stack. The steam generators have a common fuel oil supply.

The reverse osmosis plant consists of sea water pre-treatment and a three-stage reverse osmosis system suitably equipped with chemical dosing. Permeate water is discharged to storage tanks, from where it is finally distributed to the consumers in PRC and in the power plant. Brine is discharged to PRC, maintain all environmental limits.

Phase II consists of 2×120 MW steam turbines, 4×470 t/hr. steam generators, 2xwet limestone Flue Gas Desulphurization (FGD) units and 8×504 m3/hr. Reverse Osmosis (RO) trains. The similar design principle as mentioned above was applied, anyhow two boilers are discharging into one wet limestone cross flow – counter flow FGD.

Phase I and Phase II are interconnected on HHP, HP and MP steam levels, as well as the main 110 kV sub-stations.  These facilities allow exchange of utilities between the two plants maximizing the reliability of supplied to PRC and operational flexibility. Phase 110 kV main sub-station is connected to the SEC national grid for the purpose and import as well as export of power. In addition, the plants are provided with an interconnection of boiler feed water and instrument air system. All interconnections together are allowing to supply back-up utilities from IWSPP phase II to PRC Phase I in order to keep the most essential PRC phase I plants in services, respectively allowing a safe shutdown in the condition that IWSPP phase I would suffer a total plant shutdown.

Power and Steam Production

Phase I consists of a conventional thermal power plant with 5x118MW steam turbines, 9×470 t/hr. steam generators, 3xwet limestone Flue Gas Desulphurization (FGD) units. All steam generators and turbines are connected through one common High-High Pressure (HHP) steam header. The steam turbines are backpressure cum condensing units with High Pressure (HP), Medium Pressure (MP) and Low Pressure (LP) steam extractions feeding respective steam headers. In addition, each turbine is supplying steam to a LP feed water heater. To increase operation flexibility and cater for emergency situations, the headers can also be supplied through 100% redundant Pressure Reducing and De-superheating Stations (PRDS).

The steam generators are equipped with individual Electrostatic Precipitators (ESP) downstream the ESPs, the flue gas paths of three boilers are connected, discharging the flue gases to a wet limestone once through Flue Gas Desulphurization (FGD) plant before leaving the stack. The steam generators have a common fuel oil supply.

Phase II consists of 2×120 MW steam turbines, 4×470 t/hr. steam generators, 2xwet limestone Flue Gas Desulphurization (FGD) units. The similar design principle as mentioned above was applied, anyhow two boilers are discharging into one wet limestone cross flow – counter flow FGD.

The Rabigh IWSPP 1 & 2, running as an integrated plant, is synchronized with the Grid through a new SEC Substation adjacent to the Rabigh Complex. Since the construction completion of Phase 2, this connection further enhances the backup power supply capacity of the integrated plant. Further, upon detection of grid conditions that require the Rabigh Complex from disconnecting from the grid, the Rabigh IWSPP has the capability to automatically switch to island mode operation, assuring continuation of uninterrupted utilities supply to Petro Rabigh.

The plant supplies steam on various pressure levels. The steam turbines are consuming High-High Pressure (HHP) steam. Moreover, through the Turbine Extraction System, steam of different conditions is extracted from the turbines at different stages. Through extraction, the plant can supply steam at various pressure level of High Pressure (HP Steam), Medium Pressure (MP Steam) and Low Pressure (LP Steam) to Petro Rabigh. Various steam conditioning is also achieved through let down stations and appropriate de-superheating.

The power plant also produces demineralized water through a water demineralization process which consumes water that is produced by the desalination plant.

Desalinated Water Production

The reverse osmosis plant consists of sea water pre-treatment and a three-stage reverse osmosis system suitably equipped with chemical dosing. Permeate water is discharged to storage tanks, from where it is finally distributed to the consumers in PRC and in the power plant. Brine is discharged to PRC, maintain all environmental limits.

With a capacity of 12,000 t/h, the Seawater Reverse Osmosis (‘SWRO’) Desalination Plant within RAWEC’s facilities is a three pass RO plant consisting of 24 individual RO units 16 units in Phase I and 8 units in Phase II using a combination of seawater and brackish water membranes, it supplies high quality desalinated water at lower cost than similarly-sized multi-stage flash (“MSF”) thermal desalination plants.

The interconnection of desalination plant phase 1 & 2 allows shifting of desalinated water between two plants. Furthermore, the holding time of desalinated water tanks has increased during the addition of Phase 2, increasing the reliability of desalinated water supply.

The desalination plant employs energy recovery turbines to partially recuperate the power consumption of the high-pressure pumps. This assists in achieving low auxiliary power consumption and increases the overall efficiency of the plant.

Health, Safety, Social and Environmental Management (HSSE)

The plant has been designed in such a way that it fulfills the stringent requirements of the environmental impact assessment that had been undertaken prior to starting the project. The plant owners and the operator are committed to sustainable operation of the equipment and to operate and maintain the plant safely at all times.

Electrostatic Precipitator

There are 13 Electrostatic Precipitators (EP) that serve as the first filtration devices to remove fine particles from the flowing flue gas before entering the wet Flue Gas Desulphurization units. By inducing electrostatic charge, the EPs effectively separate the solid particles producing ash. The ash produced by the EP units is stored temporarily in an ash silo and is regularly collected for proper disposal.

Flue Gas Desulphurization (FGD) System

One of the key aspects in the overall design of the Rabigh IWSPP is to make Plant operation environmentally acceptable. In addition to the EPs, we have been able to achieve this with the installation of the first wet Flue Gas Desulphurization (“FGD”) system ever to be built in Saudi Arabia, relying on locally supplied limestone.

The FGD system is designed to go beyond meeting all current local and international environmental standards with regard to emissions. Indeed, it reduces sulfur in the exhaust significantly below the applicable legal requirements and contributes strongly to improving the ambient sulfur concentrations in the area.

The main function of the FGD is to control the amount of sulfur dioxide (“SO2”) emitted into the atmosphere. The Rabigh IWSPP is configured with five (5) FGD units. By utilizing the limestone forced-oxidation system, the amount of SO2 in the flue gas is significantly reduced and an oxidized gypsum product is produced. The produced gypsum is partly recycled and utilized in local cement plants as part of the cement production process.