Facilities and Operations
Production Facilities
Sasol Synfuels operates two coal-gasification-based Fischer-Tropsch synthesis plants in Secunda:
- Sasol II: Commissioned 1980
- Sasol III: Commissioned 1982
Gasification Technology
- Gasifiers: 80 Sasol-Lurgi Fixed Bed Dry Bottom (FBDB) gasifiers
- Capacity: Each gasifier converts thermal coal into synthesis gas (syngas) using oxygen and steam at 1,300°C
- Feedstock Processing: ~33-40 million tons of coal annually supplied by Sasol Mining
Synthesis Technology
- Reactors: Nine Sasol Advanced Synthol (SAS) reactors configured with high-temperature Fischer-Tropsch synthesis
- Catalyst: Fused iron-based catalyst
- Process Conditions: Elevated pressure (~350 psi) and temperature (~350°C)
- Output: Hydrocarbons, reaction water, and oxygenated hydrocarbons
Production Capacity and Output
- Total Capacity: Approximately 150,000-160,000 barrels per day (bpd)
- Annual Production: 7.5-7.7 million tons per annum (mt/a)
- Production Split: Approximately 60% energy products; 40% chemical feedstocks
- Fuel Composition: Approximately 65% petrol; 35% diesel
Feedstock Supply
Coal Supply
- Source: Sasol Mining operates six coal mines
- Secunda-area mines: Bosjesspruit, Brandspruit, Middelbult, Syferfontein, Twistdraai
- Additional suppliers: External coal purchases supplement internal production
- Quality Management: Coal quality monitoring is critical for optimum production and operational stability
- Storage: Strategic coal stockpiling maintained above 1.5 million tons
Natural Gas Supply
- Secondary Feedstock: ~10% of syngas production supplemented by natural gas
- Sourcing: Imported from Mozambique via 865 km ROMPCO pipeline
- Autothermal Reforming: Natural gas converted to syngas via autothermal reformers for process feed and recycling
Production Process
Step 1: Coal Gasification
Thermal coal is gasified in Lurgi Fixed Bed reactors at 1,300°C with oxygen and steam to produce raw syngas containing:
- Carbon monoxide and hydrogen (primary components)
- Nitrogen, carbon dioxide, and hydrocarbons
- Impurities (tar, oils, ammonia, sulfur compounds)
Step 2: Syngas Conditioning
- Cooling and purification to remove condensates and recover co-products
- Recovery of tars, oils, pitches, ammonia, sulfur, and phenols
- Cryogenic separation and cleaning processes
Step 3: Fischer-Tropsch Synthesis
- Purified syngas reacted in SAS reactors to produce hydrocarbons via the iron-based catalyst and high-temperature synthesis
Step 4: Product Fractionation
- Cooling to liquify hydrocarbon products
- Fractionation to separate various product streams by molecular weight
- Recovery of methane-rich gas for process recycle and external sale as pipeline gas
- All fractions further processed and marketed
Products
Primary Products (Energy - 60%)
- Synthetic petrol (gasoline)
- Synthetic diesel
- Jet fuel components
- Industrial heating fuels
- Pipeline methane-rich gas (MRG)
Secondary Products (Chemicals - 40%)
- Chemical feedstock for downstream operations
- Tar and tar-derived products
- Oils and pitches
- Ammonia
- Sulfur
- Phenols
- Various co-products from the syngas conditioning and fractionation process
Energy Integration
Power Generation
- Capacity: 600 MW from coal (via steam generation); 200 MW from natural gas
- Self-Sufficiency: Generates approximately 50% of its own electricity requirements
- Feedstock: Combines coal gasification-derived process heat with dedicated coal-fired and natural gas-fired power plants
Utilities Provision
Secunda Synfuels Operations supplies steam, electricity, and processing utilities to co-located Secunda Chemicals Operations, creating an integrated energy-chemicals complex.
