UniversaBio Fuel

Molecular Model

Molecule Catalog

Representative sewage-to-fuel molecules and molecular classes used to model HTL conversion, hydrotreating, sidestreams, products, and contaminants.

33

Representative molecules and indicators

30

Entries with SMILES for RDKit checks

19

Molecular classes across feed, process, product, and risk

What this means

Sewage is modeled as a mixture, not one molecule

The model uses representative molecules for sludge water, carbohydrates, amino acids, lipids, HTL oxygenates, nitrogen heterocycles, upgrading hydrogen, diesel-range hydrocarbons, gases, nutrients, and PFAS risk. These molecules let the software check formula mass, H/C and O/C ratios, heteroatom burden, upgrading severity, and sidestream risk before experimental data is available.

Class

Process medium

HTL reactor

Water

H2O
MW
18.0
H/C
n/a
O/C
n/a
N atoms
0
Hetero
1

Hot compressed water is the reaction medium for hydrothermal liquefaction and keeps wet sludge from needing an energy-intensive drying step.

ValidationMeasure feed moisture and HTL aqueous phase load.
O

Class

Carbohydrate proxy

Feedstock organic solids

Glucose

C6H12O6
MW
180.2
H/C
2.00
O/C
1.00
N atoms
0
Hetero
6

Represents carbohydrate and cellulose-like sludge organics that form oxygenated aqueous products, gases, char, and some oil-range fragments.

ValidationMeasure volatile solids, COD, carbohydrate fraction, and aqueous COD after HTL.
C(C1C(C(C(C(O1)O)O)O)O)O

Class

Protein amino-acid proxy

Feedstock organic solids

Glycine

C2H5NO2
MW
75.1
H/C
2.50
O/C
1.00
N atoms
1
Hetero
3

Represents protein-derived nitrogen that can become ammonia, nitrogen heterocycles, and hydrotreating burden.

ValidationMeasure total nitrogen, ammonia, biocrude nitrogen, and aqueous nitrogen.
C(C(=O)O)N
Feedstock organic solids

Alanine

C3H7NO2
MW
89.1
H/C
2.33
O/C
0.67
N atoms
1
Hetero
3

Represents microbial biomass/protein carbon and nitrogen in sludge.

ValidationTrack nitrogen into oil, aqueous phase, gas, and char.
CC(C(=O)O)N

Class

Lipid backbone proxy

Feedstock organic solids

Glycerol

C3H8O3
MW
92.1
H/C
2.67
O/C
1.00
N atoms
0
Hetero
3

Represents the glycerol backbone released from triglyceride-like sludge lipids and fats.

ValidationMeasure lipid/fats/oils/grease fraction and aqueous COD.
C(C(CO)O)O

Class

Fatty-acid lipid proxy

Feedstock organic solids

Palmitic acid

C16H32O2
MW
256.4
H/C
2.00
O/C
0.13
N atoms
0
Hetero
2

Represents saturated fatty acids that are strong precursors for oil-range hydrocarbons after deoxygenation.

ValidationMeasure lipid fraction, oil yield, oxygen removal, and hydrocarbon product slate.
CCCCCCCCCCCCCCCC(=O)O
Feedstock organic solids

Oleic acid

C18H34O2
MW
282.5
H/C
1.89
O/C
0.11
N atoms
0
Hetero
2

Represents unsaturated fatty acids in sludge fats and oils that can contribute to biocrude and diesel-range hydrocarbons.

ValidationTrack hydrogen demand and liquid product stability during hydrotreating.
CCCCCCCCC=CCCCCCCCC(=O)O

Class

HTL oxygenate intermediate

Biocrude and aqueous phase

Phenol

C6H6O
MW
94.1
H/C
1.00
O/C
0.17
N atoms
0
Hetero
1

Represents phenolic oxygenates that can appear in biocrude and increase upgrading severity.

ValidationMeasure biocrude oxygenates, phenolics, and hydrotreating deoxygenation.
c1ccccc1O

Class

Aqueous organic intermediate

HTL aqueous phase

Acetic acid

C2H4O2
MW
60.1
H/C
2.00
O/C
1.00
N atoms
0
Hetero
2

Represents soluble organic acids that contribute to aqueous COD and may be digested or require treatment.

ValidationMeasure soluble COD, BMP methane potential, ammonia, and nitrification response.
CC(=O)O

Class

Nitrogen heterocycle

Biocrude impurity

Pyridine

C5H5N
MW
79.1
H/C
1.00
O/C
0.00
N atoms
1
Hetero
1

Represents nitrogen heterocycles that can persist in sludge biocrude and create denitrogenation burden.

ValidationMeasure total nitrogen, basic nitrogen, and nitrogen species before and after hydrotreating.
n1ccccc1
Biocrude impurity

Indole

C8H7N
MW
117.2
H/C
0.88
O/C
0.00
N atoms
1
Hetero
1

Represents heavier nitrogen aromatics that can make drop-in fuel claims premature.

ValidationRun GC/MS or equivalent nitrogen-speciation checks on upgraded product.
c1ccc2[nH]ccc2c1

Class

Upgrading reagent

Hydrotreating

Hydrogen

H2
MW
2.0
H/C
n/a
O/C
n/a
N atoms
0
Hetero
0

Required to remove oxygen, nitrogen, and sulfur and to saturate unstable biocrude fragments.

ValidationMeasure kg H2 per fuel-equivalent output and use a sourced hydrogen carbon intensity.
[H][H]

Class

Diesel-range hydrocarbon proxy

Upgraded fuel product

Dodecane

C12H26
MW
170.3
H/C
2.17
O/C
0.00
N atoms
0
Hetero
0

Represents paraffinic diesel-range hydrocarbons that are a desired upgraded product class.

ValidationMeasure distillation range, hydrocarbon distribution, stability, and blendstock specification.
CCCCCCCCCCCC

Class

Naphthenic hydrocarbon proxy

Upgraded fuel product

Cyclohexane

C6H12
MW
84.2
H/C
2.00
O/C
0.00
N atoms
0
Hetero
0

Represents saturated cyclic hydrocarbons that may appear after upgrading aromatic or cyclic biocrude fractions.

ValidationTrack aromatic saturation and product volatility.
C1CCCCC1

Class

Aromatic hydrocarbon proxy

Biocrude/product fraction

Toluene

C7H8
MW
92.1
H/C
1.14
O/C
0.00
N atoms
0
Hetero
0

Represents aromatic hydrocarbon behavior in raw or partially upgraded product.

ValidationMeasure aromatics and stability in product fractions.
Cc1ccccc1

Class

Gas product

AD, gas, and aqueous polishing

Methane

CH4
MW
16.0
H/C
4.00
O/C
0.00
N atoms
0
Hetero
0

Represents biogas/RNG output from anaerobic digestion and possible gasification/polishing routes.

ValidationMeasure methane yield, methane slip, and gas composition.
C
Gas and carbon ledger

Carbon dioxide

CO2
MW
44.0
H/C
0.00
O/C
2.00
N atoms
0
Hetero
2

Represents biogenic and non-biogenic carbon flows that affect LCA boundary accounting.

ValidationSeparate biogenic CO2 from external fossil energy and hydrogen emissions.
O=C=O

Class

Nitrogen sidestream

Aqueous phase and treatment

Ammonia

NH3
MW
17.0
H/C
n/a
O/C
n/a
N atoms
1
Hetero
1

Represents nitrogen release from proteinaceous sludge and a key load on wastewater treatment biology.

ValidationMeasure ammonia, total nitrogen, nitrification response, and return-stream load.
N

Class

Nutrient/ash proxy

Residuals and nutrient recovery

Phosphoric acid

H3PO4
MW
98.0
H/C
n/a
O/C
n/a
N atoms
0
Hetero
5

Represents phosphorus-bearing nutrient/ash chemistry that may affect residual value or disposal.

ValidationMeasure phosphorus, ash chemistry, metals, and permitted residual route.
OP(=O)(O)O

Class

PFAS risk indicator

Feedstock and residuals

PFOA indicator

C8HF15O2
MW
414.1
H/C
0.13
O/C
0.25
N atoms
0
Hetero
17

Represents PFAS screening risk that can decide whether biosolids-derived products and residuals have an acceptable route.

ValidationScreen with EPA Method 1633 or appropriate PFAS method and map industrial dischargers.
SMILES handled as PFAS indicator class
Aqueous phase and residuals

PFBA indicator

C4HF7O2
MW
214.0
H/C
0.25
O/C
0.50
N atoms
0
Hetero
9

Represents short-chain PFAS transformation products that can be more mobile in process water.

ValidationMeasure as part of a PFAS panel and pair with total organofluorine where available.
SMILES handled as PFAS indicator class

Class

Aqueous nitrogen risk marker

HTL aqueous phase and return stream

Pyrazine

C4H4N2
MW
80.1
H/C
1.00
O/C
0.00
N atoms
2
Hetero
2

Represents recalcitrant nitrogen heterocycles that can persist in HTL aqueous phase and stress nitrification.

ValidationMeasure before and after biological polishing and compare against nitrification inhibition assays.
c1cnccn1
HTL aqueous phase

2-pyrrolidinone

C4H7NO
MW
85.1
H/C
1.75
O/C
0.25
N atoms
1
Hetero
2

Represents soluble lactam chemistry that can carry protein-derived nitrogen and oxygen into the aqueous treatment load.

ValidationTrack with targeted organic nitrogen methods across raw and polished HTL aqueous phase.
O=C1CCCN1
HTL aqueous phase

Pyrrolidine

C4H9N
MW
71.1
H/C
2.25
O/C
0.00
N atoms
1
Hetero
1

Represents saturated cyclic amine chemistry that can appear in catalyst-dependent aqueous-phase profiles.

ValidationMeasure alongside ammonia, total nitrogen, COD, and inhibition response.
C1CCNC1
HTL aqueous phase

Piperidine

C5H11N
MW
85.2
H/C
2.20
O/C
0.00
N atoms
1
Hetero
1

Represents cyclic amines that may route sludge protein nitrogen into return-stream treatment burden.

ValidationMeasure concentration and correlate with activated-sludge and AD compatibility tests.
C1CCNCC1
HTL aqueous phase and polished effluent

4-methylquinoline

C10H9N
MW
143.2
H/C
0.90
O/C
0.00
N atoms
1
Hetero
1

Represents alkylated quinoline-type heteroaromatics that can persist after biological treatment.

ValidationUse high-resolution MS or targeted heteroaromatic analysis after biological polishing.
SMILES handled as PFAS indicator class

Class

Aqueous oxygenate risk marker

HTL aqueous phase

Cresol

C7H8O
MW
108.1
H/C
1.14
O/C
0.14
N atoms
0
Hetero
1

Represents phenolic oxygenates that can dominate some HTL aqueous phases depending on sludge and catalyst.

ValidationMeasure phenolics, UV254, COD, and biological inhibition before return-stream acceptance.
Cc1ccc(O)cc1
Aqueous-phase upgrading product

2-pentanone

C5H10O
MW
86.1
H/C
2.00
O/C
0.20
N atoms
0
Hetero
1

Represents ketone chemistry that can appear when HTL aqueous carbon is upgraded or recovered.

ValidationMeasure volatile organics and product distribution during aqueous-phase upgrading.
CC(=O)CCC

Class

Fuel-quality marker

Upgraded diesel-range product

Hexadecane

C16H34
MW
226.4
H/C
2.13
O/C
0.00
N atoms
0
Hetero
0

Represents straight-chain paraffinic hydrocarbons that support high cetane renewable diesel quality.

ValidationMeasure diesel-range paraffins, cetane index, cold-flow behavior, distillation, and stability.
CCCCCCCCCCCCCCCC
Upgraded diesel or jet-range product

Decalin

C10H18
MW
138.3
H/C
1.80
O/C
0.00
N atoms
0
Hetero
0

Represents saturated cyclic hydrocarbons that can support dense diesel or jet-range fractions.

ValidationMeasure naphthenes, aromatics, density, volatility, and product fraction behavior.
C1CCC2CCCCC2C1
Biocrude and upgraded product

Naphthalene

C10H8
MW
128.2
H/C
0.80
O/C
0.00
N atoms
0
Hetero
0

Represents polycyclic aromatic content that can affect smoke, thermal stability, and hydrotreating severity.

ValidationMeasure polycyclic aromatics before and after hydrotreating and compare to product-specific limits.
c1ccc2ccccc2c1
Biocrude impurity and hydrotreating burden

Carbazole

C12H9N
MW
167.2
H/C
0.75
O/C
0.00
N atoms
1
Hetero
1

Represents neutral nitrogen heteroaromatics that challenge deep hydrodenitrogenation.

ValidationMeasure neutral nitrogen species and require near-complete removal before diesel or SAF claims.
c1ccc2c(c1)[nH]c3ccccc23
Biocrude impurity and hydrotreating burden

Dibenzothiophene

C12H8S
MW
184.3
H/C
0.67
O/C
0.00
N atoms
0
Hetero
1

Represents refractory sulfur heteroaromatics that can burden hydrotreating and sulfur compliance.

ValidationMeasure sulfur species, total sulfur, catalyst activity loss, and finished-fuel sulfur level.
c1ccc2c(c1)sc3ccccc23