Life cycle assessment of biocrude production from livestock manure in Germany via hydrothermal liquefaction
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▶ Watch the plant in motion: animated process diagramWhich configuration performs best?
Every result of the thesis turned into a key performance indicator with a definition, a formula and, where one exists, a benchmark. Pick a scenario to see how it scores.
Indicative GHG saving against fossil fuel
Saving vs the RED II fossil comparator (94 g CO₂ eq/MJ), with the 65% threshold for new plants and 50% for older plants. Indicative only: cradle to gate on an HHV basis, upgrading and use not included, biogenic CO₂ counted as emitted.
Status of every benchmarked KPI
✓ pass · ! watch · ✕ fail against the KPI's benchmark. KPIs without a benchmark are left out.
Three ways to run the plant
Wet manure is pumped as a slurry through hot, pressurised water and breaks down into biocrude, gas, solids and an aqueous phase. Cases 2 and 3 add a step that cleans the aqueous phase.
Case 1
Where 88.5 tonnes an hour of slurry ends up
Four fifths of the slurry leaves as water-rich aqueous phase. Treating that stream (cases 2 and 3) returns about 99% of it as clean water with a COD below 250 mg/L.
Mass flows, kg/h
Ribbon width is proportional to mass. 2,000 t/day of wet manure (78.76% moisture) mixed to a 20 wt% solids slurry. Hover a ribbon for its flow.
Product yields from the dry manure
% of 17,700 kg/h dry feed. They add up to just over 100% because some water reacts into the products.
What the gas is made of
HTL off-gas composition, wt%.
From wet manure to an energy-dense oil
HTL concentrates carbon and hydrogen and strips out nitrogen. The biocrude's heating value of 39.1 MJ/kg is in line with other manure biocrudes.
Elemental composition, raw manure → biocrude
Cattle manure vs other manures
Biocrude heating value compared with the literature
Higher heating value, MJ/kg. The raw manure is shown for scale.
The conversion step drives the climate impact
Per kilogram of bio-oil, cradle to gate. Switch the impact category to see how transport and electricity take over once climate change is set aside.
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Wind power lowers every impact
The same plant on German grid electricity instead of wind. Each line starts at the wind result and ends at the grid result, as a multiple of the wind value.
Case 1. Cases 2 and 3 have the same AP, EP and toxicity results.
Fossil CO₂ outweighs everything else a thousand times
Air emissions per kilogram of bio-oil for the base case on wind electricity. Bars are on a logarithmic scale: each gridline is ten times the one before.
Who carries the burden, and how much water it takes
Allocating impacts between co-products
Prices: biocrude 400 €/t, biochar 200 €/t, wastewater 1.64 €/m³.
Water use of pre-processing
Inventory per kilogram of bio-oil
Recomputed from the Aspen Plus mass balance for each scenario, with the GaBi background process for every input.
| Flow | Direction | Amount | Unit | Background process |
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Checking the numbers
Rebuilding the thesis as code makes every figure traceable. These checks compare the tables, the text and the mass balance. Items marked "review" are worth correcting in a future paper.