Senior Process Engineer

About the Company

Nexus PMG is an engineering firm providing services to the power and energy sectors focusing on the application of advanced and emerging tech, traditional and renewable energy and low-carbon solutions. With focus areas in guiding investors, developers, and owner's teams through every phase of sustainable capital infrastructure projects in the circular economy. We offer a comprehensive suite of services tailored to the needs of infrastructure funds, private equity firms, owners, and developers. With extensive experience in transitioning companies into commercialization, Nexus PMG offers a full array of services to nascent and emerging tech companies as well as implementers and developers.

• Advisory, Due Diligence and Consulting: Providing world-class technical, operational, and financial diligence to infrastructure investors and developers alike while advising debt and equity investors throughout the project finance and M&A process to protect our client's interests.
• Independent Engineering: Producing bankable engineering reports that capture technical, commercial, operational, and financial data required to secure underwriting of even the most complex of projects.
• Owner's Engineering, Engineering Services and Project Management: Building and implementing project execution plans that meet the needs of financial institutions, minimizing CapEx and delivering highest quality projects on time and on budget. Providing the complete engineering needs for discreet engineering projects.
• Front-End Engineering, EPCM and EPC Services: Providing support to developers on all aspects of projects across finance and development - from the conceptual phase to front-end engineering to structure robust RFP packages for optimum EPC pricing - and detail design engineering, procurement and construction management services to support post-financial close. Partnering with local, regional and national construction companies, Nexus PMG can provide complete plant solutions through delivery, commissioning and operations.
• Operations and Field Services: Ensuring project success from execution to operations with operational readiness and performance improvement services including a proprietary benchmarking tool that can perform readiness assessments as well as comprehensive project turnarounds; tailored programs for commissioning and start-up support for technologically diverse projects; and targeted performance improvement initiatives for existing facilities.

Position Summary

The Senior Process Engineer owns the process basis of design for renewable fuels and industrial chemical facilities from feasibility through startup. The role develops heat and mass balances, process simulations, process flow diagrams, piping and instrumentation diagrams, equipment sizing, and operating philosophies, then defends those deliverables to clients, independent engineers, lenders, and permitting authorities. The engineer sets the technical foundation the mechanical, electrical, civil, structural, and controls disciplines build against, and carries the design through performance testing and guarantee demonstration.

Key Responsibilities

Process Design and Simulation

• Develop process basis of design, design criteria, and battery limit conditions for new facilities and expansions.
• Build and maintain steady-state and dynamic process models in Aspen Plus, and document convergence, property methods, and thermodynamic package selection.
• Produce heat and mass balances at design, turndown, and off-design cases, and reconcile modeled yields against pilot data, vendor guarantees, and operating plant performance.
• Develop block flow diagrams, process flow diagrams, and piping and instrumentation diagrams, and lead their review and issue.
• Size and specify process equipment: distillation columns, reactors, fermenters, digesters, evaporators, dryers, heat exchangers, separators, scrubbers, membranes, adsorption beds, pumps, and compressors.
• Perform heat integration and pinch analysis, and quantify steam, cooling water, power, and natural gas consumption per unit of product.
• Develop utility balances, wastewater and emissions load summaries, and consumable and catalyst consumption rates.
• Define hydraulics and line sizing, control valve conditions, and instrument process data for the mechanical and controls disciplines.
• Write process descriptions, operating philosophies, control narratives, cause and effect matrices, and startup and shutdown sequences.

Process Safety and Risk

• Perform relief system design and documentation per API 520 and 521, including fire, blocked outlet, and two-phase relief cases.
• Lead or serve as process authority in hazard and operability studies, process hazard analyses, and layer of protection analysis, and close the resulting actions.
• Develop safety instrumented function requirements and safe operating limits.
• Apply OSHA process safety management requirements, recognized and generally accepted good engineering practice, and applicable NFPA standards to flammable, combustible, and toxic services.

Project Execution

• Serve as discipline lead across front-end loading stages FEL-0 through FEL-3 and into EPC execution, controlling scope, hours, schedule, and deliverable quality against the project execution plan.
• Scale process deliverables to the stage gate: FEL-0 opportunity framing and order-of-magnitude screening; FEL-1 feasibility with block flow diagrams, preliminary heat and mass balances, and Class 5 estimate inputs; FEL-2 concept selection with process flow diagrams, equipment lists, and Class 4 estimate inputs; and FEL-3 FEED with issued piping and instrumentation diagrams, equipment datasheets, relief system design, and Class 3 estimate inputs.
• Prepare stage gate documentation and present process scope, alternatives, and open risks at FEL-1, FEL-2, and FEL-3 gate reviews.
• Prepare and defend engineering estimates, deliverable registers, and man-hour budgets.
• Prepare equipment datasheets and requisitions, evaluate technical bids, and issue technical bid tabulations.
• Review licensor and vendor process packages, resolve technical deviations, and integrate third-party technology into the overall facility design.
• Support capital cost estimating with equipment lists, sized quantities, and material takeoff inputs, and support operating cost models with consumption and yield data.
• Respond to requests for information and field queries during construction, and issue as-built process documentation.
• Support commissioning, startup, and performance testing, including test protocol development, data reconciliation, and guarantee demonstration.

Compliance and Permitting Support

• Design to ASME B31.3, ASME Boiler and Pressure Vessel Code Section VIII, API standards, ISA 5.1, and applicable NFPA standards.
• Provide process data supporting air permit applications, including emission source characterization, control device performance, and best available control technology analysis.
• Support Renewable Fuel Standard, Low Carbon Fuel Standard, and Section 45Z pathway work, including carbon intensity modeling, mass balance documentation, and third-party verification response.
• Seal and issue process calculations and drawings as Engineer of Record where licensure permits.

Technical Leadership

• Check the work of junior and mid-level process engineers.
• Mentor engineering staff, and set discipline standards, simulation conventions, and calculation methods.
• Present technical positions to clients, lenders, independent engineers, and authorities having jurisdiction.

Required Qualifications

Education

• Bachelor of Science in Chemical Engineering, or a closely related engineering discipline, from a program accredited by the Engineering Accreditation Commission of ABET.
• Coursework or demonstrated depth in thermodynamics, reaction engineering, separations, and transport phenomena.

Experience

• Ten or more years of process engineering experience in fuels, chemicals, or process industries.
• Five or more years of that experience with an engineering, procurement, and construction organization, an owner's engineer, or an AE of Record firm delivering capital projects.
• Renewable fuels process experience, including both ethanol production and renewable natural gas.
• Industrial chemical process experience, including reaction, separation, and purification unit operations.
• At least two projects carried from process design through startup, with named responsibility for the process scope.
• Demonstrated authorship of heat and mass balances, process flow diagrams, and piping and instrumentation diagrams issued for construction.

Software

• Aspen Plus, Aspen HYSYS, or an equivalent process simulation platform (ProMax, PRO/II, CHEMCAD, or UniSim) is required.
• Microsoft Excel at an advanced level, including calculation workbooks with documented assumptions and version control.
• AutoCAD or an equivalent platform for review and markup of process drawings.

Technical Skills

• Distillation and stripping design, including tray and packing selection, efficiency, and turndown.
• Fermentation, enzymatic conversion, and anaerobic digestion process design and yield modeling.
• Biogas conditioning and upgrading, including hydrogen sulfide removal, siloxane removal, dehydration, and membrane, pressure swing adsorption, or amine carbon dioxide separation.
• Molecular sieve dehydration, evaporation, centrifugation, and thermal drying operations.
• Heat exchanger thermal design and rating, including fouling allowance and approach temperature selection.
• Relief and vent sizing, flare and vent header hydraulics, and depressurization analysis.
• Physical property estimation, phase behavior, and selection of equations of state and activity coefficient models.
• Material selection for corrosive, fouling, and high-temperature service, coordinated with the mechanical discipline.
• Cost estimating inputs, sensitivity analysis, and technoeconomic model support.

Professional Skills

• Technical writing that withstands third-party review by independent engineers, lenders, and regulators.
• Direct client communication, including presentation of design decisions and resolution of technical disputes.
• Discipline coordination across concurrent projects and competing schedules.
• Judgment on when to escalate risk, and documentation of assumptions and open items.

Preferred Qualifications

• Active Professional Engineer license in at least one U.S. jurisdiction, with willingness to obtain licensure by comity in additional states within 12 months of hire. Licensure is preferred, not a condition of employment.
• Master of Science in Chemical Engineering.
• Project Management Professional certification.
• Carbon intensity modeling experience in GREET, CA-GREET, or an equivalent model, and familiarity with pathway application and verification requirements.
• Experience with sustainable aviation fuel, renewable diesel, hydrogen, ammonia, carbon capture, or corn oil and protein separation technologies.
• Experience with anaerobic digestion of manure, food waste, or industrial sludge, and with dissolved air flotation residuals.
• Operating plant experience, including production support, debottlenecking, or turnaround engineering.
• Experience defending estimate class and accuracy range at front-end loading gate reviews, including value improving practice workshops.
• Experience with modular and skid-mounted process design and transport limitations.
• Experience supporting federal grant applications, DOE loan program work, or tax equity technical due diligence.
• Computational fluid dynamics or reaction kinetics modeling experience.

Work Environment and Physical Requirements

• This position works from the Greenville, SC office five days per week. The role requires daily in-person collaboration across disciplines and access to shared project resources. Remote and hybrid arrangements are not available for this position.
• Site visits occur at operating facilities and active construction sites and require personal protective equipment, ascent of ladders and stairs, and work in extreme heat, cold, dust, and around process hazards.
• The role occasionally requires extended hours during proposal periods, submittal milestones, and startup.