Production of petroleum by an industrial process

 It is possible to turn biomass (including leaves) into petroleum-like liquids (“biocrudes”) and then upgrade them into drop‑in fuels using thermochemical refinery processes. Below is how it happens in nature, and the industrial routes that mimic key chemistry.

How fossil petroleum forms in nature (geologic timescales)

• Biomass deposition: Organic matter (algae, plankton, plants) accumulates in oxygen‑poor settings.
• Diagenesis: Early chemical/biological alteration makes waxy, insoluble kerogen dispersed in sedimentary rock.
• Catagenesis (“oil window”): Over millions of years at roughly 60–150 °C and elevated pressure, kerogen thermally cracks to liquid/gas hydrocarbons.
• Migration and trapping: Oil and gas move into reservoir rocks and accumulate.

Industrial “factory” routes that convert biomass to petroleum-like liquids
Conceptually, all routes do three things: remove oxygen and heteroatoms from biomass, reshape carbon skeletons to the desired chain lengths, and separate products into usable fractions.

1. Feedstock preparation

• Size reduction: chip/grind to uniform particles; remove stones/metals.
• Moisture/ash management:
  • Drying for pyrolysis or gasification.
  • Slurrying wet biomass (e.g., algae, food waste) for hydrothermal liquefaction (HTL).
  • Leaves have relatively high ash/mineral content; co-feeding with wood or pre‑leaching minerals can improve outcomes.

2. Primary conversion (make a “biocrude” or a synthesis gas)

• Fast pyrolysis (thermal cracking without oxygen)

  • What it does: Rapidly heats dry biomass in an inert atmosphere to decompose lignocellulose into vapors that condense as a dark bio‑oil plus char and gas.
  • Outputs: 50–70 wt% bio‑oil from clean wood; leaves often yield less liquid and more char due to ash and composition.
  • Chemistry highlights: depolymerization and cracking of cellulose/hemicellulose to anhydrosugars and light oxygenates; lignin to phenolics; extensive oxygen content remains.

• Hydrothermal liquefaction (HTL)

  • What it does: Converts wet biomass slurries in hot compressed water to a hydrophobic biocrude.
  • Typical regime: Subcritical/supercritical water conditions; produces a denser, less oxygenated oil than fast pyrolysis.
  • Good for: High‑moisture feedstocks; tolerant of some ash/minerals.
  • Chemistry highlights: dehydration, decarboxylation, retro‑aldol, and recondensation reactions in water; lower O/C in product than pyrolysis oils.

• Gasification → Fischer–Tropsch (FT) or other synthesis

  • What it does: Partially oxidizes biomass to syngas (CO + H2), cleans and conditions it, then catalytically synthesizes hydrocarbons (FT), methanol-to-gasoline (MTG), or other fuels.
  • Strength: Produces truly oxygen‑free hydrocarbons after synthesis; flexible on product slate (diesel, jet, waxes).
  • Tradeoffs: Capital- and cleanup‑intensive; overall liquid yield depends on syngas conditioning and synthesis.

• Catalytic fast pyrolysis or solvent liquefaction (variants)

  • Add acid zeolites (e.g., HZSM‑5) or hydrogen‑donor solvents to partially deoxygenate and shift products toward gasoline‑range aromatics/olefins during primary conversion.

3. Separation and cleanup

• Condense vapors; filter out char/coke; separate aqueous and organic phases (pyrolysis produces a large aqueous phase; HTL yields a separable biocrude).
• For gasification: remove tars/particulates; scrub acid gases (H2S, HCl, NH3); adjust H2/CO ratio.

4. Upgrading the crude to refinery‑grade streams
   Biocrudes from biomass are too oxygen‑rich, acidic, and unstable to be used directly. Upgrading removes heteroatoms and reshapes molecules.

• Hydrotreating/hydrodeoxygenation (HDO)

  • Catalysts: sulfided CoMo or NiMo on alumina are standard; noble metals or Ru/C variants appear in HTL upgrading.
  • Reactions: remove oxygen as H2O, nitrogen as NH3, sulfur as H2S; saturate olefins/aromatics as needed.
  • Goal: raise H/C ratio and thermal stability, cut acidity and oxygen to near‑petroleum levels.

• Hydrocracking and isomerization

  • Catalysts: bifunctional metal/acid (e.g., Ni‑W or Pt on zeolites).
  • Reactions: crack heavy species; isomerize to improve cold flow; tune into naphtha, kerosene/jet, diesel ranges.

• Catalytic cracking/aromatization (for pyrolysis vapors or oils)

  • Zeolites like HZSM‑5 can steer toward gasoline‑range aromatics/olefins; reduces oxygen but can lower overall liquid yield.

• Product finishing and fractionation

  • Distill to standard cuts (naphtha, jet, diesel).
  • Blend and test against fuel specs (e.g., oxygen content, acidity, stability, sulfur/nitrogen limits, cetane/octane, cold‑flow).

Chemistry themes that matter

• Biomass starts with high oxygen and low H/C compared with petroleum. Core reactions are dehydration, decarboxylation, decarbonylation, hydrogenation, cracking, and oligomerization/aromatization.
• Lignin fragments are phenolic/aromatic; cellulose/hemicellulose give oxygenates (furans, acids, ketones) that need deoxygenation for stability.
• Heteroatom removal and H2 supply are central bottlenecks; hydrogen often comes from natural gas, electrolysis, or reforming light gases from the process itself.

What about “dead leaves” specifically?

• Pros: Readily available lignocellulosic biomass.
• Challenges: Higher ash (alkali/alkaline earth metals) and minerals can catalyze char/coke formation, foul catalysts, and lower liquid yields; variable moisture and composition.
• Practical approaches: Pre‑leaching to remove salts/minerals, blending with wood residues, using HTL (more ash‑tolerant) or gasification rather than straight fast pyrolysis.

Indicative outcomes (order‑of‑magnitude, highly feedstock/process dependent)

• Fast pyrolysis: ~50–70 wt% bio‑oil from dry clean wood; leaves may be lower due to ash. Oil has 15–40 wt% oxygen and is acidic/unstable until upgraded.
• HTL: ~25–45 wt% biocrude on dry basis for many lignocellulosics; lower oxygen than pyrolysis oil and better stability pre‑upgrade.
• Gasification → FT: A large share of biomass energy can be converted to liquids; the rest becomes electricity/heat. Products are true hydrocarbons after synthesis and upgrading.

Key takeaway

• You can’t “factory‑make” fossil petroleum from leaves, but you can make biocrudes and then upgrade them to drop‑in fuels using:
  • Fast pyrolysis + hydrotreating/hydrocracking
  • Hydrothermal liquefaction + hydrotreating
  • Gasification + Fischer–Tropsch (or MTG)
• Each route has distinct equipment, catalysts, hydrogen needs, and fuel qualities. Leaves are usable but not ideal; blending or pre‑treatment improves results.

Safety note

• These processes involve high temperatures, high pressures, flammable gases, and corrosive compounds. They require industrial reactors, gas cleanup, and strict safety and environmental controls; they are not suitable for DIY or informal settings.

In addition:

Several companies are already converting biomass (including wood waste and sometimes leafy residues) into “biocrudes” and upgrading them into drop‑in fuels, or co‑processing the biocrudes in existing refineries. Most are at pilot or first‑of‑a‑kind demo scale, with a few commercial deployments. Here are concrete examples by pathway.

Fast pyrolysis → bio‑oil → co‑processing or upgrading

• Pyrocell + Preem (Sweden): Pyrocell’s sawdust fast‑pyrolysis plant supplies bio‑oil that Preem co‑processes at its refinery to make renewable gasoline/diesel/jet components.
• BTG-BTL / Empyro (Netherlands): Operates fast‑pyrolysis units producing bio‑oil; Empyro’s oil has been used for process heat and as a feed for further upgrading projects.
• Fortum/Valmet (Finland): Integrated fast‑pyrolysis line at a CHP plant in Joensuu produced bio‑oil for district heating; technology also targeted at refinery co‑processing.
• Ensyn / Envergent (U.S./Canada): Produces “renewable fuel oil” via RTP fast pyrolysis for heating markets and has worked with refiners (via Honeywell UOP) on co‑processing/hydrotreating trials.
• Green Fuel Nordic (Finland): Fast‑pyrolysis oil production used in regional heating and explored for refinery co‑processing.

Catalytic fast pyrolysis/aromatization (chemicals-oriented, fuels possible)

• Anellotech (U.S.): Pilot‑scale catalytic pyrolysis (TCat) making BTX aromatics from woody biomass; demonstrates in‑situ deoxygenation and gasoline‑range aromatics chemistry, with potential fuels applications.
• Historical note: KiOR (U.S.) attempted catalytic pyrolysis to drop‑in fuels; the company failed, but the pathway informed today’s designs.

Hydrothermal liquefaction (HTL) → biocrude → hydrotreating/hydrocracking

• Steeper Energy + Silva Green Fuel (Norway): Demonstration HTL plant at Tofte processing woody residues to biocrude; downstream hydrotreating tested with refinery partners.
• Licella (Australia) / Arbios Biotech (Canada): Deploying Cat‑HTR HTL for woody residues; first commercial projects are in development, with prior extensive pilot/demo runs.
• Genifuel (U.S./Canada): PNNL‑derived HTL for wet wastes (e.g., wastewater sludge); first‑of‑a‑kind municipal projects are being built/commissioned, with biocrude upgrading proven at pilot scale.

Gasification → syngas → Fischer–Tropsch (FT) or MTG → hydrocarbons

• Enerkem (Canada): MSW gasification to methanol/ethanol at demo scale (Edmonton) and a large commercial facility under construction (Varennes, Quebec). Methanol can be upgraded to gasoline (MTG) or to jet via alcohol‑to‑jet routes.
• Fulcrum BioEnergy (U.S.): Sierra BioFuels Plant (Nevada) designed to convert MSW to FT syncrude/SAF; first‑of‑kind project has faced commissioning delays but continues to pursue SAF production.
• Velocys (UK/U.S.): Supplies FT reactors for biomass/MSW‑to‑SAF projects (e.g., Bayou Fuels in Mississippi; Altalto in the UK) that are in development/permitting phases.
• Red Rock Biofuels (U.S., Oregon): Attempted woody‑biomass gasification‑to‑FT; project stalled/cancelled, illustrating the pathway’s execution risk.

Related large‑scale renewable “drop‑in” fuels (not from leaves, but often co‑processed in refineries)

• HVO/renewable diesel and SAF from fats/oils (Neste, ENI, TotalEnergies, Valero/Diamond Green Diesel, Preem, etc.) are fully commercial today. Different feedstock chemistry than lignocellulose, but the refinery hydrotreating/hydrocracking steps are analogous to those used to upgrade biocrudes from pyrolysis/HTL.

What this means in practice

• The steps you asked about are real and operating: making a biocrude from biomass (fast pyrolysis or HTL), then hydroprocessing it alone or co‑processing it in a petroleum refinery. Gasification‑to‑FT is also being pursued, though it’s capital‑intensive and has seen schedule risk.
• Scale is still modest compared with fossil refineries, and first‑of‑kind projects can face delays. But co‑processing of pyrolysis oils (e.g., Preem) and HTL demos (e.g., Steeper/Silva Green Fuel) show the chemistry and unit ops are viable.