RDKit-parsed nitrogen marker molecules
Docker-Generated Nitrogen Control Screen
Nitrogen Control Lab
A 3D nitrogen-split lab for protein nitrogen, oil N-heterocycles, aqueous ammonia, hydrotreating burden, catalyst risk, and WRRF return-load controls.
nitrogen-control strategies scored
top individual control lead
modeled first-stage oil N after best reported reduction
Reduce upgrading burden. Prioritizes upstream nitrogen diversion and mild stabilization before expensive deep HDN.
Separated two-stage HTL 2026 municipal-sludge bench
A low-temperature first stage can divert nitrogen-rich hydrolysates before high-temperature oil formation.
Oil yield penalty, first-stage aqueous TN/COD, ammonia speciation, carbon loss, and whether lower oil nitrogen reduces later hydrogen demand.MgCl2 mineral steering 2025 sewage-sludge bench
Magnesium chloride is a lead for lower-N/O biocrude while coupling phosphorus and nitrogen recovery.
Chloride corrosion, magnesium dose, phosphorus product purity, aqueous chloride, and metals/PFAS co-partitioning.Citric acid hydrothermal pretreatment Sequential HTL precedent
Mild acid hydrothermal pretreatment can solubilize nitrogen before liquefaction and reduce the nitrogen burden of the oil pathway.
Acid recycle, carbon loss, metals solubilization, first-stage water treatment, and site-sludge response.Mild hydrotreatment stabilization 2026 pilot trickle-bed
Mild NiMo hydrotreatment stabilizes sewage-sludge biocrude, but nitrogen remains persistent and should not be counted as final HDN.
Stable 240 C operation, pressure drop, MCR, SFC-HRMS nitrogen classes, H2/oil ratio, and catalyst exposure time.SFC-HRMS / FT-ICR nitrogen forensics Specialist analytical workflow
Bulk nitrogen does not identify pyridines, indoles, quinolines, amides, or amines; molecular forensics explains catalyst and stability outcomes.
Paired feed/intermediate/product samples, ionization bias, class assignment, GC/MS alignment, and link to catalyst performance.The Docker selection model picks Separated two-stage HTL + MgCl2 mineral steering + Mild hydrotreatment stabilization + HTL-aqueous ammonia recovery + SFC-HRMS / FT-ICR nitrogen forensics as the first nitrogen control package. Pyomo-formulated five-strategy nitrogen package with oil-N, aqueous-N, upgrading, analytics, nutrient-recovery, residual-risk, and cost gates; solved by deterministic enumeration.
Current nitrogen decision
Use pretreatment to move nitrogen before asking hydrotreating to solve everything
The generated screen ranks separated two-stage HTL first because it directly targets protein-derived nitrogen before high-severity oil formation. That still leaves a gap to finished-fuel nitrogen targets, so the first package couples upstream nitrogen splitting with MgCl2 mineral steering, molecular forensics, and process-water nitrogen recovery.
Representative sewage-sludge HTL biocrude nitrogen burden before treatment.
Used only as a screened lead; site sludge still needs measured validation.
Gap to a conservative 1 wt% oil-N interim target before deeper upgrading.
Reduce upgrading burden
50.6Oil nitrogen first
Prioritizes upstream nitrogen diversion and mild stabilization before expensive deep HDN.
- Oil N
- 54.8
- Aqueous N
- 34
- HDT relief
- 54.8
- Residual risk
- 38.8
Fuel-spec pathway
38.5Refinery readiness
Pairs stabilization, deep HDN, molecular forensics, and nitrogen return-load controls before finished-fuel claims.
- Oil N
- 26.8
- Aqueous N
- 33.2
- HDT relief
- 35.6
- Residual risk
- 34
Protect WRRF biology
37Aqueous containment
Assumes nitrogen diverted from oil must be closed in HTL-aq before headworks return or discharge.
- Oil N
- 18.4
- Aqueous N
- 70.8
- HDT relief
- 16
- Residual risk
- 45.6
Do not chase yield alone
36.4Yield-quality tradeoff
Keeps aqueous recycle under a hold gate because yield gains can accumulate N-heterocycles and lower oil quality.
- Oil N
- 22
- Aqueous N
- 26.4
- HDT relief
- 26.8
- Residual risk
- 38.4
Generated nitrogen package
Pyomo-gated five-strategy control package
Separated two-stage HTL
Oil yield penalty, first-stage aqueous TN/COD, ammonia speciation, carbon loss, and whether lower oil nitrogen reduces later hydrogen demand.
MgCl2 mineral steering
Chloride corrosion, magnesium dose, phosphorus product purity, aqueous chloride, and metals/PFAS co-partitioning.
Mild hydrotreatment stabilization
Stable 240 C operation, pressure drop, MCR, SFC-HRMS nitrogen classes, H2/oil ratio, and catalyst exposure time.
HTL-aqueous ammonia recovery
NH4-N loading, stripping or membrane duty, acid use, recovered product quality, and return-stream compatibility.
SFC-HRMS / FT-ICR nitrogen forensics
Paired feed/intermediate/product samples, ionization bias, class assignment, GC/MS alignment, and link to catalyst performance.
Molecular markers
What the assays and model should track
Glycine C2H5NO2
- Phase
- feed / aqueous
- N atoms
- 1
- LogP
- -0.97
- TPSA
- 63.32
Alanine C3H7NO2
- Phase
- feed / aqueous
- N atoms
- 1
- LogP
- -0.582
- TPSA
- 63.32
Acetamide C2H5NO
- Phase
- aqueous / oil
- N atoms
- 1
- LogP
- -0.508
- TPSA
- 43.09
Caprolactam C6H11NO
- Phase
- oil
- N atoms
- 1
- LogP
- 0.677
- TPSA
- 29.1
Pyridine C5H5N
- Phase
- oil / aqueous
- N atoms
- 1
- LogP
- 1.082
- TPSA
- 12.89
Aminopyridine C5H6N2
- Phase
- aqueous
- N atoms
- 2
- LogP
- 0.664
- TPSA
- 38.91
Pyrrole C4H5N
- Phase
- oil
- N atoms
- 1
- LogP
- 1.015
- TPSA
- 15.79
Indole C8H7N
- Phase
- oil
- N atoms
- 1
- LogP
- 2.168
- TPSA
- 15.79
Quinoline C9H7N
- Phase
- oil
- N atoms
- 1
- LogP
- 2.235
- TPSA
- 12.89
Aniline C6H7N
- Phase
- oil
- N atoms
- 1
- LogP
- 1.269
- TPSA
- 26.02
Ammonia H3N
- Phase
- aqueous
- N atoms
- 1
- LogP
- 0.162
- TPSA
- 35
Urea CH4N2O
- Phase
- aqueous
- N atoms
- 2
- LogP
- -0.976
- TPSA
- 69.11
Strategy ledger
Each option has to prove both oil and water-side nitrogen behavior
Pretreatment nitrogen split63.4
Separated two-stage HTL
A low-temperature first stage can divert nitrogen-rich hydrolysates before high-temperature oil formation.
- Oil N
- 88
- Aqueous N
- 54
- HDT relief
- 78
- Risk
- 46
Mineral additive55.2
MgCl2 mineral steering
Magnesium chloride is a lead for lower-N/O biocrude while coupling phosphorus and nitrogen recovery.
- Oil N
- 72
- Aqueous N
- 48
- HDT relief
- 58
- Risk
- 62
Mild acid pretreatment54.1
Citric acid hydrothermal pretreatment
Mild acid hydrothermal pretreatment can solubilize nitrogen before liquefaction and reduce the nitrogen burden of the oil pathway.
- Oil N
- 76
- Aqueous N
- 62
- HDT relief
- 58
- Risk
- 42
Upgrading stabilization47.6
Mild hydrotreatment stabilization
Mild NiMo hydrotreatment stabilizes sewage-sludge biocrude, but nitrogen remains persistent and should not be counted as final HDN.
- Oil N
- 38
- Aqueous N
- 6
- HDT relief
- 68
- Risk
- 34
Severity programming45.5
Consecutive two-stage HTL
A programmed low/high-temperature profile can protect yield, but it can also promote cyclic nitrogen species if the liquid is not removed.
- Oil N
- 52
- Aqueous N
- 36
- HDT relief
- 42
- Risk
- 34
Deep upgrading45.1
Deep hydrodenitrogenation
Finished diesel/SAF claims eventually require deep nitrogen removal, but this is the expensive hydrogen and catalyst-life step.
- Oil N
- 92
- Aqueous N
- 4
- HDT relief
- 96
- Risk
- 50
Aqueous nutrient recovery36.7
HTL-aqueous ammonia recovery
If pretreatment moves nitrogen into process water, ammonia recovery becomes part of the fuel plan rather than a side treatment.
- Oil N
- 4
- Aqueous N
- 84
- HDT relief
- 2
- Risk
- 36
Analytical gate32.5
SFC-HRMS / FT-ICR nitrogen forensics
Bulk nitrogen does not identify pyridines, indoles, quinolines, amides, or amines; molecular forensics explains catalyst and stability outcomes.
- Oil N
- 0
- Aqueous N
- 0
- HDT relief
- 12
- Risk
- 10
WRRF compatibility30.4
Nitrification return-load test
WRRFs with nitrogen permits cannot return HTL-aq without testing nitrification inhibition and hazardous pollutant removal.
- Oil N
- 0
- Aqueous N
- 72
- HDT relief
- 0
- Risk
- 40
Aqueous biodegradation29.6
UASB / AD plus microaeration screen
Process water can be biodegradable but inhibitory; methanogenesis, ammonia, COD, and feedstock chemistry must be measured together.
- Oil N
- 0
- Aqueous N
- 68
- HDT relief
- 0
- Risk
- 48
Yield-quality tradeoff26.2
Aqueous recirculation hold gate
Aqueous recycle can improve yield, but recent sewage-sludge data show N-heterocycles accumulating and oil quality declining.
- Oil N
- 20
- Aqueous N
- 18
- HDT relief
- 12
- Risk
- 74
Aqueous oxidation24.7
Wet oxidation aqueous polish
Wet oxidation can reduce COD/TOC and supply heat, but nitrogen can become ammonium and oxygen service raises corrosion burden.
- Oil N
- 0
- Aqueous N
- 76
- HDT relief
- 0
- Risk
- 58
nitrogen-two-stage-sludge-2026
Two-stage HTL of municipal sludge for nitrogen migration control
Reports separated two-stage municipal-sludge HTL can reduce oil nitrogen while shifting most nitrogen into the aqueous phase.
Open sourcenitrogen-model-protein-2026
Nitrogen transformation of model protein during two-stage HTL
Mechanistic protein-N source for temperature-dependent organic nitrogen, ammonia, and N-heterocycle formation.
Open sourcenitrogen-mild-hdt-2026
Mild hydrotreatment stabilization of nitrogen-rich sewage-sludge biocrude
Open-access pilot trickle-bed study showing stabilization boundaries, limited nitrogen conversion, and persistent nitrogen species.
Open sourcenitrogen-mgcl2-2025
Low-nitrogen and oxygen biocrude plus N/P recovery with MgCl2
MgCl2-assisted sewage-sludge HTL lead for lower heteroatom burden and coupled nutrient recovery.
Open sourcenitrogen-aq-recycle-2026
Aqueous phase recirculation in sewage-sludge HTL
Shows yield gains but N-heterocycle accumulation and oil-quality deterioration across recirculation cycles.
Open sourcenitrogen-process-water-ad-2025
HTL process-water toxicity and biodegradation for anaerobic digestion
Open-access evidence that process-water chemistry affects methanogenesis, biodegradation, and microaeration feasibility.
Open sourcenitrogen-aq-nitrification-2025
Aerobic biological treatment of sewage-sludge HTL process water
Sewage-sludge HTL-aq treatment source for nitrification inhibition, pollutant removal, and WRRF return-load gates.
Open sourcenitrogen-wrf-ammonia-recovery
Water Research Foundation ammonia recovery and HTL-aqueous integration project
Project framing ammonia recovery and anaerobic treatment as HTL-aqueous integration requirements for WRRF scale-up.
Open sourcenitrogen-sludge-review-2025
Municipal sludge HTL biocrude production and fuel-quality upgrading review
2025 review of sludge-derived biocrude heteroatom burden, upgrading paths, and pilot integration gaps.
Open sourcenitrogen-rsc-wet-waste-2026
Wet-waste HTL TEA/LCA with upgrading strategies
2026 product-slate and upgrading context for marine fuel, renewable diesel, and SAF cases.
Open sourcenitrogen-sequential-2021
Sequential hydrothermal processing of sewage sludge to produce low-nitrogen biocrude
Earlier sequential hydrothermal treatment precedent using water and acid pretreatments before HTL.
Open sourcenitrogen-two-stage-hdt-2020
Two-stage catalytic hydrotreatment of highly nitrogenous biocrude
Staged hydrotreating precedent for highly nitrogenous HTL biocrudes and coke reduction.
Open sourcenitrogen-continuous-wo-2025
Continuous wet oxidation of HTL aqueous phase
Continuous wet oxidation source for COD/TOC removal, oxidant choice, and ammonium/process-integration implications.
Open sourcenitrogen-frontiers-aq-2026
HTL aqueous phase treatment and downstream implications
2026 editorial summary emphasizing HTL-aq treatment, nitrification inhibition risk, product recovery, and WRRF integration.
Open sourcenitrogen control is not proven until oil nitrogen, aqueous ammonia, N-heterocycles, catalyst life, and product specs are measured together