PTQ Q4 2026 Issue

products, such as LDPE, HDPE, LLDPE, PP, PVC, VCM, styrene, phenol, bisphenol, PTA, phthalic anhydride, and others. In addition to these main products, several other components can be utilised to produce a variety of val - uable specialty chemicals. Incorporating such chemi - cals not only completes the entire value chain but also enhances revenue genera- tion and profitability. Low-value streams to fertilisers Even after integrating the

Reduced CO emission

Less CO

Scope 1 emission

Scope 3 emission

Less CO

Less Fuel

HGU

Less CO

ROG

Jet/kero Diesel Propylene Butadiene Benzene Toluene Xylene Propylene Ethylene

Steam cracker

Isomerisation

NHT

Aromatics unit

CCR

KHT

CDU / VDU

Crude

DHDT

LCO

VGO HDT

Gasoline

FCC

Treatment

HCO

DCU

Coke

Figure 1 Integrated refinery and petrochemical complex

molecular valorisation, with significant implications for both economic viability and environmental sustainability. This reallocation enhances process economics while substan - tially reducing carbon emissions by minimising fuel com - bustion and promoting the production of durable materials. Key process modifications involve directing reformate to aromatics extraction, optimising the FCC unit for olefin and aromatic yields, and implementing utility integration strate - gies to maximise heat and energy recovery. Additionally, the hydrogen generation unit shares capac - ity with the cracker, ensuring an efficient hydrogen supply for hydroprocessing and hydrocracking. The off-gas recov - ery system captures fuel gases and upgrades them for use as cracker feedstock. Collectively, these advancements contribute to the reduction of both Scope 1 and 3 carbon emissions, supporting a transition towards more sustain - able hydrocarbon processing systems while maximising overall process efficiency. Figure 1 shows an example of an integrated refinery and petrochemical complex, illustrating how carbon emissions are reduced. Primary products obtained from the cracker complex include ethylene, propylene, butadiene, and aromatics such as benzene, toluene, and xylenes. These are further pro - cessed to manufacture plastics and other petrochemical

refinery with petrochemicals and speciality chemicals, the complex will generate some low-value streams or waste products, such as H₂S, NH₃, and CO₂, which can be recovered and utilised as valuable feedstocks for fer - tiliser production. Crude oil typically contains impurities such as nitrogen and sulphur, which are converted into NH₃ and H₂S during hydrotreatment and are present in sour water. The NH₃ is usually stripped from the sour water and routed to the sulphur recovery unit (SRU) for combustion or destruction. However, this recovered NH₃ can be further processed and fed into the fertiliser complex as a valuable raw material. Moreover, it eliminates NH₃-induced corro - sion in the refinery SRU. Figure 2 depicts the proposed NH₃ recovery pathway instead of the existing NH₃ destruction pathway. Sulphur recovery pathways Similarly, H₂S is stripped from sour water and sent to the SRU for sulphur recovery. So, the refinery has its SRU along with sulphur storage and dispatch facilities. Standalone fertiliser plants typically include an on-site sulphuric acid production unit. Solid sulphur is imported, melted, and com - busted to produce sulphur dioxide, which is then converted

first to sulphur trioxide and ultimately to sulphuric acid. Alternatively, H₂S from the refinery can be directly converted into H₂SO₄ (see Figure 3 ), which can then be used as a feedstock for the fertiliser plant. This concept removes several steps, such as solid sulphur storage, transportation, and melting, leading to reduced Capex, lower manpower require - ments, less plot area, and improved efficiency and ease of operation.

Chemical Pathway

Conventional destruction in SRU

Nitrogen in crude

NH in sour water

Proposed Pathway

Fertiliser feedstock

NH recovery

Compression

Liquefaction

Figure 2 NH₃ recovery pathway

PTQ Q4 2026