Sasol Limited Sustainability Report 2021 - Book - Page 46
SUSTAINABILITY PERFORMANCE AGAINST OUR FOCUS AREAS: MINIMISING OUR ENVIRONMENTAL FOOTPRINT (CONTINUED)
Air quality abatement achievement: Progress to date (2015-2021)
Prior to 2015, our Secunda, Sasolburg and Natref operations invested in several projects and initiatives aimed at reducing
emissions. By the time the Atmospheric Pollution Prevention Act , 45 of 1965 permits were replaced by atmospheric
emission licences (AELs), 80% of our point and area emission sources for Secunda and point emission sources for
Sasolburg and Natref were compliant with the newly promulgated minimum emission standards (MES) with the residual
point sources being addressed through air quality compliance roadmaps in accordance with postponements granted.
Since 2015, we have implemented several projects at Secunda, Sasolburg and our joint venture Natref operations, aligned
with our commitment to progressively reduce our emissions in accordance with our air quality roadmaps to meet the MES
as prescribed in the National Environmental Management: Air Quality Act, 39 of 2004. We have already met compliance
milestones for 98% of our point and area emission sources for Secunda and point emission sources for Sasolburg and Natref.
The remaining sources form part of the last part of our compliance journey to enable compliance of our mature plants
with the same standards applicable to newly commissioned plants by 1 April 2025 in accordance with postponements
(extended compliance timeframes) granted.
PM emission reduction
Boiler / steam plant achievements for PM reduction within Secunda and Sasolburg Operations include:
Secunda Operations achievements for TVOC reduction:
• Piloting of three technologies at commercial scale in Secunda Operations to determine the most suitable technology
(refer to Secunda Operations PM case study on the next page).
• Installation of seven RTOs in our Secunda tar value chain to abate TVOCs from a total of 114 emission sources.
• Installation of high frequency controllers at seven of our boilers’ electrostatic precipitators at Secunda,
reducing PM emissions from the eastern boiler plant by approximately 20%.
• Routing TVOCs from three pitch tanks to the installed RTOs.
• Upgrade of the electrostatic precipitators of seven of the 12 operational boilers at Sasolburg which included the
evaluation of a mechanical pre-separation device (grit collector). Due to extreme space constraints, the upgrade
included a novel application of the technology in a hot gas environment which is constantly being evaluated to ensure
PM emissions are sustainably below the new plant standards.
• Developing an emission baseline for 345 tanks through detailed analytical measurements and confirming that
342 tanks on the Secunda site are currently in compliance with the MES based on a systematic approach which
was aligned and supported by DFFE.
Natref achievements for PM reduction include:
• Replacement of the catalytic cracker cyclones in 2016.
• Replacement of crude and vacuum distillation unit furnaces to allow for 100% fuel gas firing in 2012, which, in addition
to lower PM emissions led to a reduction in NOx and SO2.
• Fuel oil firing phase-out by December 2019 to reduce PM, which in addition to a PM reduction, also reduced SO2.
• Routing the TVOCs from four phenosolvan saturation columns to the installed RTOs.
• Optimisation of the vapour recovery unit at the fuel loading facility to meet MES requirements.
Natref achievements for TVOC reduction:
• Natref tank farm VOC abatement was completed on three tanks through installation of a dedicated vapour recovery
• Before the implementation of the MES, Natref had already installed secondary roof seals on all seven crude tanks,
11 petrol and heavy oil tanks, and 17 petrol components tanks.
• To further improve, Natref has installed geodesic dome roofs with internal floating disks on two crude tanks and one
petrol tank which results in improved VOC dispersion.
NOx emission reduction
SO2 emission reduction
Boiler / steam plant achievements for NOx reduction within Secunda and Sasolburg Operations include:
• To ensure suitability with our operations, we adapted low NOx burner technologies for our facility as well as for the
unique characteristics of South African coal.
Sasolburg Operations achievements for SO2 reduction:
• 32 low NOx burners were installed on two boilers at Secunda Operations.
• 24 low NOx burners were installed on four of the 12 operational boilers at Sasolburg after numerous equipment failures
resulting in changes, rectification and redesign. This includes the successful installation of a low NOx burner in a
boiler that was constructed in the 1950s which is currently in the testing and sustainable operation evaluation phase.
The installations on Steam Station 2 have resulted in a 44% reduction over the last four financial years, however the
performance of the low NOx burners are under constant evaluation to ensure the NOx emissions are sustainably below
the new plant standards.
Natref achievements for NOx reduction:
• Given the nature of the coal in Sasolburg, we identified coal blending as the most suitable solution to address the SO2
concern in Sasolburg, however we continue to investigate optimisation work on various coal blends.
Natref achievements for SO2 reduction:
• Installation of a hydrogen sulphide (H2S)/SO2 analyser at the sulphur recovery unit tailgas for optimal sulphur recovery.
• Re-routing of one of the largest SO2 emission sources at Natref (sour water stripper off-gas which accounts for
approximately 48% of SO2 emissions) to the sulphur recovery unit to reduce SO2 emissions and to recover additional
sulphur as a saleable product to the market.
• Switching to lower sulphur crudes: Natref has steadily reduced SO2 emissions from the refinery by actively sourcing
lower sulphur crude oil.
• Installation of new heaters with low NOx burners as part of an upgrade to the diesel unifiner in 2010, which resulted
in a reduction of NOx emissions.
Ammonia nitrate reduction
• Various maintenance and operational improvements within the ammonia nitrate plant, within our Secunda Operations,
have resulted in a reduction in emissions to within the MES.
Sasol Sustainability Report 2021