Refinery Process Operator Jobs in California (NOW HIRING)

Location: San Francisco, CA

Travel: ~15–20% for pilot work, vendor trials, and partner visits

Reports to: CTO

Hyfé is seeking a process development engineer who will turn lab and pilot data into decision-ready process models. This role is designed for someone who learns quickly, embraces ambiguity, and is motivated to build scalable, sustainable solutions to some of the world’s most pressing problems.

• Data and analysis. You will own the flow of data from the lab and pilot to process design. You will reconcile and close mass and energy balances, investigate outliers, and document underlying assumptions, such that the data is reliable and defensible for design and economic decisions.

• Process modeling and economics. You will build and maintain an Aspen Plus flowsheet with appropriate property methods for aqueous, electrolyte, and biopolymer streams. You will translate model outputs into techno-economic inputs (yields, utilities, throughput, consumables), run focused sensitivity analyses, and summarize what matters for decisions.

• Experiment design and scale-up. You will collaborate with chemists to design lean experiments that reduce uncertainty in process performance and product quality. You will engage with equipment suppliers to size and cost unit operations and to plan targeted trials.

• Process design and documentation. You will draft and iterate PFDs, P&IDs, control notes, and operating procedures that reflect pilot learning and safety considerations. You will contribute to risk reviews such as structured risk registers (FMEA) and pre-HAZOP activities.

• Communication and external deliverables. You will write concise decision memos and prepare clear slides for leadership, investors, and customers. You will contribute figures and process descriptions to support patent and grant applications.

• BA in Chemical Engineering or a closely related field with 4+ years of experience

• Demonstrated hands‑on problem solving in a startup, or similarly fast‑paced environment.

• Ability to perform mass- and energy‑balance reconciliation on imperfect data and to explain the accuracy and precision of common analytical methods (e.g. HPLC, UV-Vis).

• Proficiency with process‑modeling tools such as Aspen Plus or SuperPro Designer, including justification of property‑method selection and definition of pseudo‑components for complex streams.

• Proficiency in techno‑economic modelling (TEM), including running sensitivity and uncertainty analyses, and communicating key cost and risk drivers.

• Clear, concise written communication, strong organization, and the ability to present recommendations that enable timely decisions.

• PhD in Chemical Engineering or closely related field with 1-4 years of experience

• Experience building an Aspen Plus model for aqueous or electrolyte systems and translating model outputs into economic evaluations.

• Working knowledge of experimental design; sensitivity analysis or simple Monte Carlo methods; and data analysis in JMP, Python, or similar tools.

• Experience with biomass preprocessing (for example, milling and solids handling), membranes, filtration, centrifugation, evaporation, or ion‑exchange resins.

• Experience drafting process diagrams and participating in structured risk identification.

• Competitive annual salary, commensurate with experience

• 15 days PTO, paid holidays, and year‑end office closure (pending business performance)

• 401(k) plan

• Comprehensive health benefits, including medical, dental, and vision insurance

• Short‑term disability coverage

• In‑office snacks & drinks

See our coverage from the World Economic Forumhere.

Every year, approximately one billion tons of nutrient‑rich fruit and vegetable waste is discarded or under‑utilized across global food systems. For processors, getting rid of this waste is costly and emissions‑intensive, creating significant environmental impact with little to no economic return. Yet these waste streams contain valuable compounds that could transform the economics of businesses across the food system and help catalyze the production of sustainable chemicals and materials. Hyfé exists to change that.

Hyfé transforms food waste into high‑value ingredients using a label‑friendly, thermochemical refining process. Our products range from bioactives to fibers, and are being commercialized to make the food we eat healthier for people and the planet. Our team of scientists and engineers brings decades of expertise from the oil refining and chemical industries, specializing in scaling industrial processes and pioneering sustainable solutions.

At Hyfé, you’ll have the opportunity to build at the earliest stages of a mission‑driven company—working alongside a world‑class team, shaping real products, and helping define how the next generation of ingredients are made.

Our mission is simple: To transform carbon we waste into carbon we need.

Hyfé is an equal opportunity employer, and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, age, national origin, disability status, protected veteran status, or any other characteristic protected by law.