5-Year molten sulphur supply contract for ESKOM power stations – manufacture, delivery & offloading

Scope: Technical evaluation strategy for the supply, delivery, and offloading of liquid sulphur to Eskom power stations for FY2027–FY2031.

Purpose: Liquid sulphur is used for flue gas conditioning (FGC) to improve electrostatic precipitator (ESP) performance, reducing particulate emissions.

Context: South African coals have low sulphur content (~1%) and high ash, requiring additional SO3 injection to reduce ash resistivity in ESPs.

Full scope includes:

• Procurement/manufacture of sulphur.
• Quality testing.
• Temperature maintenance (≥120°C).
• Transport in heated tankers.
• Offloading at sites.

Technical Evaluation Team (TET) members:

• Mthoko Dlamini (Chief Engineer – Gx Engineering / Air Pollution Control)
• Mzwandile Gcaleka (Senior Advisor Engineering - Generation / Air Pollution Control)
• Rinae Muruge (Engineer Prof Engineering - Generation)

Document authorisation and development team:

• Prince Dlamini (Senior Manager: Boiler Engineering)
• Samu Seleke (Generation Engineering Documentation Controller)
• Jeff Mchunu (acknowledged contributor)

Minimum weighted final technical score required: 70%. Failure to meet any mandatory criterion results in technical disqualification.

Mandatory criteria:

• Written confirmation or proof of sulphur purity compliance (≥99.5% by mass).
• Approved company procedure for Transport and Emergency/Accident Response Preparedness.
• Valid certificate of compliance or accreditation to ISO 14001 (Environmental Management System).

Qualitative criteria (weighted scoring):

• Compliance to Eskom Specification (50%):
• Must meet all eight limits: Purity ≥99.5%, Carbon ≤0.3%, Moisture ≤0.5%, H2S ≤10 mg/kg, Arsenic ≤1 mg/kg, Selenium ≤1 mg/kg, Tellurium ≤1 mg/kg, Fluorine ≤1 mg/kg.
• Evidence: Specification sheet or confirmation letter.
• Scoring: All specifications met = 100%, Purity/Carbon/Moisture only = 80%, H2S/Selenium/Tellurium/Fluorine only = 40%, Non-responsive = 0%.
• Transport Capacity and Capability (30%):
• Lead time (50% sub-weight): <3 days = 100%, 3-6 days = 80%, >6 days = 40%, no lead time = 0%. Evidence: Previous/current monthly delivery records.
• Number of dedicated tankers (10% sub-weight): 5 tankers = 100%, 4 = 80%, 3 = 40%, <3 = 0%. Evidence: Previous/current tanker records.
• Product temperature maintenance ≥120°C (40% sub-weight): Yes = 100%, No = 0%. Evidence: Tanker details including heating mechanism.
• Technical Assurance (20%):
• Tanker cleaning prior to loading (60% sub-weight): Dedicated tankers = 100%, washing facilities at depot = 80%, neither = 0%. Evidence: Method statement.
• Proof of product conformity (40% sub-weight): Yes = 100%, No = 0%. Evidence: Sample certificate showing analysis + quality control manuals.

Note: All method statements and quality control manuals must be submitted. Failure to submit = zero score for that criterion.

Scope: Manufacture, supply, delivery, and off-loading of molten sulphur (liquid sulphur) to Eskom coal-fired power stations on an 'as and when' required basis for 5 years (FY2027–FY2031).

Purpose: Improve electrostatic precipitator (ESP) performance via flue gas conditioning (FGC) to reduce particulate emissions.

Liquid Sulphur Specification (Eskom):

• Purity: 99.5–99.9% by mass
• Carbon content: ≤0.3% by mass
• Moisture (H2O): ≤0.5% by mass
• H2S: ≤10 mg/kg
• Arsenic: ≤1 mg/kg
• Selenium: ≤1 mg/kg
• Tellurium: ≤1 mg/kg
• Fluorine: ≤1 mg/kg

Minimum Scope Requirements:

• Procurement/manufacture of sulphur.
• Testing of sulphur quality.
• Maintain minimum sulphur temperature of 120°C to keep it liquid.
• Transport and deliver in suitable heated tankers.
• Offload sulphur at various sites.

Anticipated Monthly Consumption (70% confidence level):

• Duvha: 83 tons
• Kendal: 190 tons
• Kriel: 124 tons (may shut down units May 2027–March 2030)
• Lethabo: 182 tons
• Matla: 226 tons
• Matimba: 184 tons
• Tutuka: 185 tons (supply starts August 2027, TBC; increments as SO3 plant retrofit completes).

Context: South African coals have low sulphur (~1%) and high ash content, requiring additional SO3 to reduce ash resistivity in ESPs.

Technical Evaluation Team (TET) consists of delegated engineers/technical specialists responsible for reviewing and evaluating technical aspects of the tender.

Quality requirements:

• Testing of sulphur quality is mandatory.
• Reference standard: ISO 9001 Quality Management Systems.

Evidence required:

• Method statements for tanker cleaning and product handling.
• Quality control manuals detailing conformity management.
• Sample certificate showing product analysis.

Mandatory compliance requirements (failure on any results in disqualification):

• Valid certificate of compliance or accreditation to ISO 14001 (Environmental Management System).
• Approved company procedure for Transport and Emergency/Accident Response Preparedness.
• Written confirmation or proof of sulphur purity compliance (≥99.5%).

Additional notes:

• Preferential Procurement Policy Framework Act (PPPFA) applies.
• Unacceptable technical risks: Product not meeting specification, delivery schedule not met.

Mandatory requirement: Approved company procedure for Transport and Emergency/Accident Response Preparedness to ensure safe and sustainable transport of molten sulphur.

Environmental requirements:

• Mandatory: Valid certificate of compliance or accreditation to ISO 14001 (Environmental Management System).
• Purpose: Flue gas conditioning (FGC) improves ESP performance, reducing particulate emissions.

Mandatory Technical Evaluation Criteria:

• Written confirmation or proof of sulphur purity compliance (≥99.5%).
• Approved company procedure for Transport and Emergency/Accident Response Preparedness.
• Valid certificate of compliance or accreditation to ISO 14001.

TET Responsibilities:

• Evaluate compliance to specification, transport/emergency preparedness, and delivery tanker sulphur temperatures (>120°C).
• Evaluate qualitative criteria: compliance to Eskom specification, transport capacity and capability, and technical assurance.

Unacceptable Risks:

• Product not meeting specification.
• Delivery schedule not being met.

Minimum weighted final technical score required: 70%. Failure to meet any mandatory criterion results in technical disqualification.

Mandatory criteria:

• Written confirmation or proof of sulphur purity compliance (≥99.5% by mass).
• Approved company procedure for Transport and Emergency/Accident Response Preparedness.
• Valid certificate of compliance or accreditation to ISO 14001.

Qualitative criteria (weighted scoring):

• Compliance to Eskom Specification (50%):
• Must meet all eight limits: Purity ≥99.5%, Carbon ≤0.3%, Moisture ≤0.5%, H2S ≤10 mg/kg, Arsenic ≤1 mg/kg, Selenium ≤1 mg/kg, Tellurium ≤1 mg/kg, Fluorine ≤1 mg/kg.
• Evidence: Specification sheet or confirmation letter.
• Transport Capacity and Capability (30%):
• Lead time (50% sub-weight): <3 days = 100%, 3-6 days = 80%, >6 days = 40%, no lead time = 0%.
• Number of dedicated tankers (10% sub-weight): 5 tankers = 100%, 4 = 80%, 3 = 40%, <3 = 0%.
• Product temperature maintenance ≥120°C (40% sub-weight): Yes = 100%, No = 0%.
• Technical Assurance (20%):
• Tanker cleaning prior to loading (60% sub-weight): Dedicated tankers = 100%, washing facilities at depot = 80%, neither = 0%.
• Proof of product conformity (40% sub-weight): Yes = 100%, No = 0%.

Note: All method statements and quality control manuals must be submitted. Failure to submit = zero score for that criterion.