Bioenergy and Waste-to-Energy Flashcards

Which gasification agent produces the highest heating value syngas but is too costly for most commercial waste-to-energy applications?

Answer: Pure oxygen

Pure oxygen gasification produces high-quality syngas with minimal nitrogen dilution but is economically prohibitive for most commercial WtE projects.

The Fischer-Tropsch process converts syngas into liquid fuels primarily through which reaction type?

Answer: Catalytic hydrogenation of CO and H2

Fischer-Tropsch synthesis uses catalysts to polymerize CO and H2 into liquid hydrocarbons ranging from diesel to waxes.

In a biomass integrated gasification combined cycle (BIGCC) plant, what is the primary efficiency advantage over conventional steam-only biomass power?

Answer: Use of gas turbine topping cycle before steam recovery

BIGCC achieves higher electrical efficiency by extracting work from a gas turbine first, then recovering exhaust heat in a steam cycle.

Which municipal solid waste fraction typically has the highest energy content on a dry weight basis?

Answer: Plastics

Plastics have a high calorific value (~35–45 MJ/kg dry) derived from their hydrocarbon polymer chains, exceeding most other MSW components.

What does the term 'refuse-derived fuel (RDF)' specifically refer to?

Answer: Processed and shredded MSW with non-combustibles removed for fuel use

RDF is MSW that has been mechanically processed—shredded, screened, and separated—to remove non-combustibles and improve fuel consistency.

Hydrothermal liquefaction (HTL) is particularly advantageous for which feedstock characteristic compared to conventional pyrolysis?

Answer: High-moisture content algae and wet biomass

HTL processes wet biomass in supercritical or near-critical water, avoiding the energy cost of drying that makes conventional pyrolysis inefficient for wet feedstocks.

Which metric is used to quantify how much electrical energy a waste-to-energy plant generates per tonne of waste processed?

Answer: Specific electricity output (kWh/tonne)

Specific electricity output (kWh per tonne of waste) measures the electrical generation efficiency of a WtE facility relative to waste throughput.