garbage in,

corrosion out

Problem statement

Converting municipal solid waste (MSW) into liquid fuels through gasification is chemically feasible but fails at commercial scale because the heterogeneous waste stream produces corrosive byproducts — primarily nitric acid and chlorine compounds — that destroy downstream piping and catalysts within months. Fulcrum BioEnergy raised over $1 billion and spent more than a decade attempting this before its 2024 bankruptcy, and The Chemical Engineer's post-mortem reports that similar problems — significant NOx emissions and nitric acid corrosion of downstream piping — had been observed eight years earlier at Air Products' Tees Valley project. The feedstock variability of real MSW makes it fundamentally harder to control than the homogeneous inputs used in lab demonstrations.

Why this matters

Sustainable aviation fuel (SAF) production reached 1 million tonnes in 2024 — only 0.3% of global jet fuel production (IATA) — far below what airline decarbonization commitments require. Municipal solid waste is one of the most abundant potential feedstocks — the world generated 2.56 billion tonnes in 2022 (World Bank, What a Waste 3.0), with a third or more of global waste improperly managed (dumped or openly burned). If MSW gasification could work reliably, it would simultaneously address waste disposal and clean fuel production. Airlines including United ($30 million in 2015), Cathay Pacific, and Japan Airlines (equity investment, 2018) invested directly in Fulcrum, signaling real demand.

What’s been tried and why it hasn’t worked

Fulcrum BioEnergy built a $200 million gasification plant near Reno, Nevada that began operations in 2022. Its startup was "plagued by the unexpected creation of nitric acid, which ate through the facility's equipment, causing millions of dollars of damage and months of delay" (Bloomberg, from an internal company report); a February 2023 shipment of synthetic crude contained only 350 gallons. The plant later failed again through a second mechanism — a thick, cement-like sludge built up in the gasification system, in places 10 feet high, rendering it inoperable — and stopped operating in May 2024, with Fulcrum filing for Chapter 11 that September. Air Products' Tees Valley waste-gasification project in the UK was abandoned in April 2016 at a writedown of US$900m–1bn after the company concluded that "additional design and operational challenges would require significant time and cost to rectify"; The Chemical Engineer's 2024 post-mortem of Fulcrum reports Tees Valley likewise experienced significant NOx emissions and nitric acid corrosion of downstream piping. The underlying difficulty is that real municipal waste contains nitrogen, chlorine, and sulfur compounds in varying concentrations that produce acidic gases during high-temperature gasification. Lab-scale and pilot-scale tests use pre-sorted, relatively homogeneous feedstocks that don't capture this variability. Existing gas-cleaning technologies (scrubbers, filters) are designed for more predictable industrial gas streams and can't handle the compositional variation of MSW-derived syngas.

What would unlock progress

Progress requires either (1) corrosion-resistant materials and coatings that can withstand the acidic, chlorinated syngas environment at gasification temperatures, or (2) robust real-time sensing and adaptive gas-cleaning systems that can handle the compositional variability of MSW-derived syngas, or (3) preprocessing approaches that can cost-effectively remove nitrogen and chlorine-bearing materials from the waste stream before gasification. Adjacent fields with relevant solutions include geothermal energy (corrosion-resistant well materials for hot acidic fluids), chemical processing (adaptive scrubber systems), and waste sorting (AI-driven robotic sorting for contaminant removal).

Entry points for student teams

A student team could investigate one of several scoped approaches: (1) characterize the range of corrosive species produced by gasifying different MSW compositions using small-scale reactor experiments, mapping feedstock variability to corrosion risk; (2) test candidate corrosion-resistant coatings or linings under simulated MSW syngas conditions; (3) design a low-cost inline sensor system for detecting corrosive species in syngas in real time, enabling adaptive gas cleaning. Relevant disciplines include materials science, chemical engineering, environmental engineering, and sensor design.