PTQ Q3 2026 Issue

Sample calculation sheet for predicting salt topping-up requirements

Parameters

Value

References

Formula/source

Section 1: Input data Dryer number

D-001

Rock salt

Type of salt

180

Number of days in operation, days

[A] [B] [C] [D] [E] [F] [G] [H]

From operational record From loading diagram

96,463

Amount of salt loaded, kg

200

Days average ULSD flow rate, Sm³/h

Average data from operational database Average data from operational database Average data from operational database Average data from operational database Average data from operational database

Days average temperature, °C ULSD density @ 15°C, kg/Sm³ Salt dryer inlet water, wppm Salt dryer outlet water, wppm

825 130

80 27

Solubility of salt, wt%

From solubility data

Section 2: Calculation salt consumption Amount of water removed, kg/day Amount of water removed, kg Amount of salt used, kg/day Available salt for use [topping up @50% consumption], kg Number of days available to run, days Number of days left before reload, days

198

[I] [J]

[I]=(([F]-[G])*10^-6)*([C]*[E])*24

35,640

[J]=[I]*[A]

[K]

[K]=([H]/(100-[H]))*[I]

48,231

[L]

[L]=0.5*[B] [M]=[L]/[K] [N]=[M]-[A]

670 490

[M] [N]

The calculation provides an approximate estimate of salt consumption based on equilibrium dissolution and does not account for salt loss due to fines carryover, drainage losses

Table 1

• Suspend loading activities during rainfall. Once loading is complete, preserve the salt dryer under nitrogen to prevent moisture ingress. • The top manway flange should be covered with a thick sheet to protect the sealing surface from mechanical dam- age during salt loading. Salt bed level measurement Accurately determining the remaining salt bed height dur - ing operation remains a challenge in salt dryer systems. Continuous and reliable measurement methods are limited due to the complex internal environment, which involves multiphase flow, brine formation, and salt settling. Several refiners have tested guided wave radar (GWR) level instruments for online trending of salt bed levels. However, interpretation of the results has proven difficult under typical operating conditions. As an alternative, some refiners have adopted nuclear-type level measurement, which has shown better performance in this application. Given the limitations of direct measurement, a predictive approach is commonly employed. Most refiners maintain a spreadsheet model that estimates salt consumption based on: • Inlet and outlet water content as obtained from laboratory analysis. • Flow rate through the salt dryer. • Elapsed operating time since the last loading/topping-up event. The predicted salt depletion is verified through the fol - lowing methods: • Monitoring haze or water content in the salt dryer outlet. • Taking the operating salt dryer offline and placing the standby unit in service, followed by manual level gauging through the salt gauge nozzle.

Neutron backscatter measurement can estimate salt bed height without taking the dryer offline, but typically requires temporary on-site scaffolding at intervals along the vessel. In practice, a combination of predictive modelling and manual checks remains the standard approach. A sample calculation sheet for predicting salt topping-up requirements based on elapsed time since last refill, inlet water content, and estimated salt consumption rate is pro- vided in Table 1 . Operational considerations • Sampling point: Inaccurate total water measurement at the coalescer outlet is often attributed to improper sample point design. In some facilities, the sample point is con- figured as a long closed-loop line across the coalescer, resulting in stagnant flow due to the negligible pressure drop across the coalescer. For more accurate water con- tent measurement at the salt dryer inlet and outlet, an open-to-OWS sampling point with minimal piping length is recommended. If company policy prohibits hydrocarbon discharge to OWS, a closed-loop sample line routed to the slop system may be used as an alternative. • Sampling schedule: In facilities where sampling of ULSD in parallel trains is done at different times of day, the train sampled in the afternoon often shows higher water con- tent. This is attributed to diurnal temperature variation, as elevated temperature increases the water solubility in ULSD. To ensure consistency and comparability, samples from both trains should be collected at the same time. • Brine sampling: Weekly brine sampling is recommended to monitor salt dryer performance. Measuring brine den - sity and salt concentration helps assess salt consumption trends and the effectiveness of water removal. • Operating temperature: Minimising the operating

PTQ Q3 2026