Process Engineering Automation & Deliverable Generator
Executive Summary
Developed automated process calculation and deliverable generation modules in Python and Microsoft Excel to eliminate manual transcription from simulation flowsheets. Automated equipment sizing, rating checks, and datasheet generation for safety relief valves (API 520 / 521), two-phase separators (API 12J), and centrifugal pump hydraulic calculations (TDH, NPSHa margins, and process datasheet preparation aligned with API 610 / Shell DEP formats).
Key Technical Metrics & Criteria
- Turnaround Time
- 10x Faster
- Automated Equipment Sizing & Checks
- Safety Relief
- API 520 / 521
- Programmed PSV Sizing Equations
- Separators & Pumps
- API 12J & 610
- Vessel Rating & Pump Hydraulics
- Core Tools
- Python & Excel
- Automated Engineering Workbooks
Standards, Design Codes & Specifications Applied
- API 520 Parts I & II (Relief Sizing)
- API 521 (Depressuring Systems)
- API 12J (Oil & Gas Separators)
- API 610 (Centrifugal Pumps)
- Shell DEP Standards
Process Simulation & Engineering Software Stack
- Python
- Microsoft Excel
- Aspen Simulation Workbook (ASW)
- OpenPyXL / Automation Scripts
- Engineering Calculation Sheets
Simulation Methodology & Governing Standards
Architected a modular process engineering calculation engine using Python (NumPy, pandas, openpyxl) integrated with Microsoft Excel and Aspen Simulation Workbook (ASW) via COM automation. The framework extracts thermodynamic fluid properties (compressibility Z, vapor density ρv, liquid density ρl, dynamic viscosity μ, and isentropic expansion coefficient k = Cp/Cv) directly from Aspen HYSYS process simulations into automated design workbooks without manual data entry.
Programmed rigorous sizing algorithms per API 520 Part I & II (10th Edition) for gas, liquid, steam, and two-phase flashing relief scenarios, incorporating backpressure derating factors (Kb, Kw) and discharge coefficient corrections (Kd). Integrated API 12J standards for horizontal and vertical gas-liquid separators, determining droplet settling criteria and retention volumes. Encoded API 610 (12th Edition) and Shell DEP standards for centrifugal pump hydraulics, automating Total Dynamic Head (TDH), system resistance head curves, Net Positive Suction Head Available (NPSHa), and suction specific speed (Nss) ratings.
Engineering Trade-Offs & Design Rationale
API 520 calculations yield theoretical effective relief areas (Acalc). Selecting the next standard API 526 commercial orifice designation (letters D through T) frequently introduces excessive oversizing (Aselected > 1.30 · Acalc). The automated engine calculates rated relieving capacity against required mass flow, systematically flagging oversizing factors exceeding 25% to prevent relief valve chattering, rapid seat galling, mechanical fatigue, and downstream flare header pressure spikes, recommending dual-staggered relief valves or split-range configurations where necessary.
For gas-liquid separator geometry, the algorithm iterates through standard ASME Section VIII Division 1 vessel shell and head dimensions to optimize length-to-diameter (L/D) ratios between 2.5:1 and 4.5:1. This balances vessel steel mass minimization against Souders-Brown vapor velocity limits (K = 0.07–0.12 m/s) and liquid surge residence times (3 to 5 minutes between low and high liquid levels). In centrifugal pump hydraulics, suction line piping was iteratively sized to constrain liquid velocity within 1.0 m/s to 1.8 m/s per Shell DEP while enforcing a minimum NPSH margin of 1.0 m (or 20% above NPSHr) and capping suction specific speed (Nss ≤ 11,000) to prevent acoustic cavitation, internal recirculation, and premature seal failure.
Technical Design FAQ (Direct Answer Blocks)
How does automated API 520 sizing prevent relief valve chattering caused by excessive oversizing?
Relief valves are manufactured in discrete API 526 standard orifice sizes (D through T). When a chosen standard orifice area exceeds the calculated requirement by more than 25% (Aselected > 1.25 · Acalc), the valve relieves vapor faster than the upstream process generates it. This causes upstream pressure to rapidly collapse below reseat pressure, inducing violent, high-frequency valve chattering that damages valve seats and bellows. The automation algorithm computes rated capacity, flags excessive oversizing, and recommends staggered dual-valve configurations.
How does the algorithm optimize separator length-to-diameter (L/D) ratios for minimum vessel weight?
The separator sizing module couples API 12J droplet settling equations with ASME Section VIII Division 1 shell wall thickness calculations. By sweeping across nominal vessel diameters in 2-inch increments, it evaluates required seam-to-seam length to simultaneously satisfy Souders-Brown vapor disengagement (K = 0.07–0.12 m/s) and liquid surge holdup (3 to 5 minutes retention time). Evaluating vessel steel tonnage across L/D ratios between 2.5:1 and 4.5:1 reveals the exact geometry that minimizes fabrication cost while meeting process guarantees.
Why is suction specific speed (Nss) a critical constraint in automated pump hydraulic calculations?
Suction specific speed (Nss = N · √Q / NPSHr^0.75) characterizes the suction geometry and inlet eye diameter of a pump impeller. While high Nss impellers (Nss > 11,000 in US customary units) offer lower NPSH requirements, they exhibit severe internal suction recirculation, acoustic pressure pulsations, and impeller erosion when operating below best efficiency point (BEP). The platform audits pump selections against API 610 and Shell DEP, enforcing Nss ≤ 11,000 and verifying NPSHa margins of at least 1.0 m across all continuous operating ranges.
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