PTQ Q3 2026 Issue

Water sources Ground water Surface water

Transient operations/ Maintenance Fire water Wash water Hydrotest/ush Exchanger backwashing

Steam losses ( f lare, venting)

Cooling tower evaporation

Process water consumption (H manufacturing)

Environmental sources rain, snow

(Reservoirs, rivers) Purchased water Recycled water Sea water Process unit operations Consumed in the process Hydrogen production Utilised in the process Wash water Dilution water Stripping steam Quench water

Process Unit Operation

Water source

Wastewater

Transient Operations Maintenance

Steam losses

Steam generation Wet gas scrubber Flare Venting

Fire water Hydroblasting/hydrotest, w ash - down/clean - up

Cooling tower Leaks

Recycle and reuse

Figure 4 General overview of refineries’ water sources, uses, and consumption9

justify investments in additional water treatment or the use of alternative water sources. • Equipment limitations : Poor water quality driven by the need to operate at higher cooling water or boiler cycles may result in decreased efficiency or reliability of equipment due to increased corrosion or fouling. • Restricting refinery production : Lack of water or volume or quality, such as the lack of cooling water, can restrict the throughput or product slate of the refinery. Water use audit Once a refinery’s water usage and drivers are identified, the next step in developing a water use strategy is to conduct a comprehensive water use audit. A proper water use audit should be led by experienced personnel with site credibility and include: • Quantify all water uses and losses : This is the previously mentioned water balance. • Distinguish between recoverable and unrecoverable water : Unrecoverable water is normal due to evaporative losses. These losses are driven by heat removal require- ments; can these requirements be reduced, or can alterna- tive methods of cooling be used instead? • Evaluate water quality and reuse potential : Can the

or utilised/recycled for other purposes and that which is unrecoverable. Figure 5 is a summary of the water consumption of a typ- ical refinery. As shown, much of the water consumed in the refinery (50-60%) is used for evaporative cooling and wet gas scrubbers, where most of the water is lost to evapo- ration.9 While these applications typically have a recycled water flow, which includes a purge or blowdown of the circulating water, much of the evaporated water cannot be reused or treated to be reused in another process. Some reduction in water use can be accomplished by improv- ing make-up water quality (fewer salts) or by ‘cycling up’. However, the trade-off is that fouling or corrosion can increase. Typically, inside the fence, water reuse opportunities include steam condensate recovery for boiler feedwater or wash water. Due to water’s general abundance and low cost, water reduction projects can be difficult to justify, a theme sometimes mirrored in wastewater reuse, as this often requires treatment upgrades, making it economically difficult to pursue. A clear understanding of the future water supply risk to operations is needed, which may include: • Regulatory requirements : While US federal regula - tions focus on safe drinking water quality and wastewa-

ter discharge quality, some state and local municipali- ties, driven by droughts or increasing water demand, are increasingly imposing restrictions on groundwa- ter withdrawal and surface water use. Refiners affected by these restrictions need to determine whether they are temporary or permanent, as well as assess the vol- ume and quality of available water. • Cost : The cost of purchas- ing water from a third party, such as a municipality, or the cost of treatment to improve the quality of the make-up water, may be enough to

100%

90%

Evaporative losses – Accounts for 50 - 60% or more of water consumption in a renery Potentially recoverable water Other – Maintenance or washing

80%

70%

60%

50%

40%

Recovered – Condensate, stripped water or waste W ater n o t recovered – Atmosphere or process

30%

20%

10%

Chemical process

Desalter

Coker

Other

Cooling tower

Steam Wet gas scrubber

Wash water

Fire water

Figure 5 Typical refinery water volume use by type (recovered or not recovered)9

PTQ Q3 2026