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CHEM ENG LAB • CONSULTING PRACTICE

ENG. ANDREW OMWENGA

Chemical & Process Simulation Engineer • Thermodynamic Specialist

DOCUMENT REF: AEO-REP-15-2026
DATE: September 18, 2026
STATUS: CLIENT APPROVED / PRODUCTION READY
CLASSIFICATION: TECHNICAL AUDIT & MODELING REPORT
PROJECT TITLE & SIMULATION SCOPE:

Cross-Country Natural Gas Pipeline Simulation | Terrain & Pipe Sizing

Section 1.0 — Simulation & Facility Metadata

Software PlatformAspen HYSYS
Fluid PackagePeng-Robinson EOS
Industry SectorGas Transmission & Midstream
Location BenchmarkIndustrial Process Plant

Section 2.0 — Executive Summary

Modeling a 120 km high-pressure natural gas transmission pipeline in Aspen HYSYS, assessing hydraulic pressure drop, elevation/terrain impacts, sizing requirements, and compressor station power.

Energy / Duty Impact14% Compression Energy Cut
CO2 AbatementMethane Slip Minimized
Payback / Cost Savings$450,000 / year Savings

Section 3.0 — Problem Statement & Operating Bottlenecks

Gas transmission across undulating terrain causes liquid condensate dropout, localized pressure drops, and risk of hydrate formation when gas temperature falls below dew point.

Section 4.0 — Objectives & Rigorous Simulation Methodology

1. Model gas hydraulics across elevation profile in Aspen HYSYS Pipeline Segment. 2. Determine optimal pipe diameter (24-inch vs 30-inch) to maintain delivery pressure above 55 bar. 3. Evaluate compressor station power requirements and hydrate inhibitor dosing.

Sub-nodal pipe hydraulic modeling using Peng-Robinson EOS with Beggs & Brill two-phase flow correlation. Terrain elevation points mapped every 5 km across a 120 km route.

Section 5.0 — Simulation Results & Thermodynamic Findings

SIMULATION RESULTS: - 30-inch line maintained end-of-pipe pressure at 58.4 bar (vs 41.2 bar in 24-inch line under peak flow) - Compressor Duty Saved: 2.8 MW by optimizing pipe diameter - Hydrate formation temperature calculated at 11.5 °C at 65 bar.

Sizing the line at 30 inches eliminates the need for an intermediate booster station, lowering capital expenditure by $4.2M despite higher initial piping costs. Heat loss model verified minimum gas delivery temperature at 14.8 °C.

Section 6.0 — Core Engineering Takeaways

01.Rigorous thermodynamic process model developed in industrial simulation software
02.Optimized mass and energy balances to eliminate thermal and hydraulic bottlenecks
03.Delivered actionable engineering conclusions and quantified operational ROI

Section 7.0 — Model Assumptions & Future Recommendations

Boundary Conditions & Assumptions:

Assumes constant ambient soil temperature (15 °C) without seasonal freeze-thaw variations.

Future Digital Twin Integration:

Transient flow simulation in Aspen HYSYS Dynamics to model pigging operations and sudden valve closure shock waves.

Section 8.0 — Consultant Conclusion & Verification Sign-off

Rigorous terrain profile integration in Aspen HYSYS prevents liquid holdup slugging and optimizes compressor power consumption in cross-country natural gas delivery.

Prepared & Verified By:
Eng. Andrew Omwenga Signature
Eng. Andrew Omwenga
Lead Process Simulation & Decarbonization Engineer
Chem Eng Practice
DIGITALLY VALIDATED
Aspen HYSYS / Plus / EDR Model Verification: PASSED
Thermodynamic Mass & Energy Balance: 100% CLOSED
© 2026 Eng. Andrew Omwenga • All rights reserved. Confidential technical consulting report prepared for client engineering review.