Hydrate Inhibitor Injection Calculator
Hydrate Inhibitor Requirements Calculator
Calculates required inhibitor concentration in free water and injection rate for hydrate prevention via hydrate formation temperature depression using common industry practice correlations (Hammerschmidt + Nielsen-Bucklin for methanol/water). Use for engineering screening; final dosage should be confirmed against project design basis and vendor / operations guidance.
Temperature & Hydrate Margin
Inhibitor Selection
Free Water & Injection Basis
Actions
Results
Required Inhibitor in Water (W):
- wt%
Required Depression (d):
- Β°C ( - Β°F )
Method Used:
-
Free Water Rate (converted):
- kg/h
Active Inhibitor Required:
- kg/h
Injected Liquid Required (with conc. & losses):
- kg/h
Injected Liquid Volumetric Rate:
- L/h
Total Injected Liquid (Period):
- kg ( - L )
Warning: This calculator is for engineering screening. Hydrate
risk management is highly system-specific (composition, pressure,
kinetics, subcooling distribution, water holdup, pigging, dead-legs).
Always confirm with the project hydrate/dehydration basis and
operations/vendor recommendations.
Technical Notes
Variable Definitions
- Thyd: Hydrate formation temperature at controlling pressure/composition (Β°C).
- Top: Minimum operating (flowing) temperature at risk location (Β°C).
- margin: Additional depression safety margin (Β°C).
- d: Required temperature depression, d = (Thyd β Top) + margin.
- W: Required inhibitor concentration in free water (wt% inhibitor in water phase).
- αΉw: Free water mass rate at risk location (kg/h).
- αΉinh: Active inhibitor mass rate required to achieve W in water (kg/h).
- C: Injected liquid active concentration (wt%).
- lossFactor: Allowance for distribution/vaporization/handling losses (β₯ 1.0).
- αΉinj: Injected liquid mass rate including solution concentration and losses (kg/h).
- Qinj: Injected liquid volumetric rate (L/h).
Formulas / Logic
- Required depression: d(Β°C) = (Thyd β Top) + margin; d(Β°F)=d(Β°C)Β·9/5.
- Hammerschmidt screening (wt% in water): W = 100Β·MΒ·d /(K + MΒ·d), where K is in Β°F and d is in Β°F.
- NielsenβBucklin (methanol/water screening): d = β72Β·ln(1βx) β x = 1 β exp(βd/72), then convert x to wt%.
- Active inhibitor to treat free water: αΉinh = αΉwΒ·W/(100βW).
- Injected liquid including concentration and losses: αΉinj = αΉinhΒ·lossFactor /(C/100).
- Volumetric rate: Qinj(L/h) = 1000Β·αΉinj(kg/h)/Ο.
These are common engineering screening correlations for
thermodynamic inhibition. Final chemical rates should be confirmed
with the project flow assurance basis and chemical vendor.
Assumptions / Notes
- Assumes inhibitor ultimately mixes with the free water phase at the risk location; does not model slip, stratification, or limited mixing.
- Does not account for methanol partitioning to gas/hydrocarbon phases or inhibitor consumption; use lossFactor for screening and confirm with vendor.
- Free water conversion assumes water density β 1000 kg/mΒ³ (screening).
- If d β€ 0, the method indicates no thermodynamic inhibitor is required (still confirm hydrate curve and operational margins).
- Correlations have range limitations (e.g., methanol concentration and temperature range). Warnings indicate possible range exceedance.
Standards / References
- Common flow assurance practice for thermodynamic hydrate inhibition (Hammerschmidt-type and methanol NielsenβBucklin style screening correlations).
- Project/company hydrate management basis and chemical vendor guidelines should govern final selection.
- Hydrate formation temperature Thyd should come from a validated hydrate curve/phase envelope (e.g., approved simulator or project study).