Regulator & Station Piping Sizing

Contents

Introduction

Sizing of regulator is performed using the Universal Gas Equation:

Subsonic Flow Equation

Q = C_{g} P_1 \sqrt{\frac{520}{G_f T} \sin \left[ \left(\frac{3417}{C_1}\right) \sqrt{\frac{\Delta P}{P_1}} \right]}

Q = C_{g} P_1 \sqrt{\frac{520}{G_f T} \sin \left[ \left(\frac{3417}{C_1}\right) \sqrt{\frac{\Delta P}{P_1}} \right]}

Where:
𝑄 =Gas Flowrate (scf/h)
𝐺_𝑓 = Gas Specific Gravity
𝑇 = Absolute Temperature (°R)
𝐶_𝑔 = Gas Sizing Coefficient
𝐶_𝑣 = Liquid Sizing Coefficient
𝐶₁ = 𝐶_𝑔/𝐶_𝑣
𝑃₁ = Gas Sizing Coefficient
Δ𝑃 = 𝑃₁ − 𝑃₂ − Differential Pressure Across Valve
𝑃₂ = Outlet Pressure (psia)

Sonic Flow Equation is Reduced to:

Q=C_gP_1\sqrt{\frac{520}{G_fT}}

Q=C_gP_1\sqrt{\frac{520}{G_fT}}

Case Guide

Part 1: Create Case

Select the Regulator & Station Piping Sizing application from the Regulator & Meters Module
To create a new case, click the “Add Case” button
Enter Case Name, Location, Date and any necessary notes.
Fill out all required Parameters.
Make sure the values you are inputting are in the correct units.
Click the CALCULATE button to overview results.

Input Parameters

Class Location
Temperature
F – Design Factor
T – Temperature Derating Factor
Gas Specific Gravity
Regulator Sizing Data
- P1 – Inlet Pressure
- P2 – Outlet Pressure
- Q – Flow Rate
- Gas Specific Gravity
- Flowing Gas Temperature
- C1 – Valve Recovery Coefficient
- Capacity Factor (80% Recommended)
Upstream Pipe and Operational Data
- P1 – Operating Pressure – Upstream
- Q – Flow Rate
- V – Assumed Gas Velocity
- F – Design Factor
- T – Temperature Derating Factor
- SMYS – Specified Minimum Yield Strength
- E – Longitudinal Joint Factor
Downstream Pipe Operational Data
- P2 – Operating Pressure – Downstream
- Q – Flow Rate
- V – Assumed Gas Velocity
- F – Design Factor
- T – Temperature Derating Factor
- SMYS – Specified Minimum Yield Strength
- E – Longitudinal Joint Factor

Part 2: Outputs/Reports

If you need to modify an input parameter, click the CALCULATE button after the change.
To SAVE, fill out all required case details then click the SAVE button.
To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
To generate a REPORT, click the REPORT button.
The user may export the Case/Report by clicking the Export to Excel icon.
To delete a case, click the DELETE icon near the top of the widget.

Results

Regulator Sizing Results
- Cg – Gas Sizing Coefficient – Calculated
- Cgr – Gas Sizing Coefficient – Recommended
- Flow Conditions:
Upstream Results
- ID1 – Calculated Inside Diameter (in)
- Minimum Required Pipe Wall Thickness (in)
- OD1 – Calculated Outside Diameter (in)
Downstream Results
- ID1 – Calculated Inside Diameter (in)
- Minimum Required Pipe Wall Thickness (in)
- OD1 – Calculated Outside Diameter (in)