Coupled hydrotreating sulfur and nitrogen balance

RefineryHydrotreatingSulfurNitrogenBalance creates one immutable material-balance receipt for simultaneous hydrodesulfurization and hydrodenitrogenation screening. Unlike two independent single-contaminant calculations, it solves both product targets against the same calculated liquid product mass.

This is stoichiometric accounting, not a reactor or yield model. It does not identify organic sulfur or nitrogen species or predict pathways, kinetics, catalyst performance, severity, phase equilibrium, separation, heat duty, hydrocarbon cracking, product yield, or compliance.

Coupled basis and equations

The caller supplies feed mass F; feed sulfur and nitrogen mass fractions zS and zN; target product fractions xS and xN; and explicit hydrogen assumptions nuS and nuN in mol H2 per mole of contaminant removed.

One mole of removed sulfur is booked as one mole of H2S, and one mole of removed nitrogen as one mole of NH3. The minimum stoichiometric assumptions are nuS = 1.0 and nuN = 1.5. Additional hydrogen is retained in the liquid bookkeeping balance.

Define the liquid-mass changes per kilogram removed:

aS = (nuS M_H2 - M_H2S) / M_S
aN = (nuN M_H2 - M_NH3) / M_N

The common liquid product mass P is then:

P = F (1 + aS zS + aN zN) / (1 + aS xS + aN xN)
R_S = F zS - xS P
R_N = F zN - xN P

This closed form makes both quality targets and total material closure auditable without iteration.

Java example

The public DOE SPR/OEDI Big Hill assay reconstructs 0.40867518 mass% sulfur and 0.1095129 mass% nitrogen. The 15 ppm sulfur target, 10 ppm nitrogen target, 2.0 mol H2/mol S, and 4.0 mol H2/mol N are illustrative caller assumptions.

RefineryHydrotreatingSulfurNitrogenBalance receipt =
    RefineryHydrotreatingSulfurNitrogenBalance.calculate(
        1000.0, 0.0040867518, 0.001095129,
        15.0e-6, 10.0e-6, 2.0, 4.0);

double productMassKg = receipt.getProductMassKg();
double totalHydrogenKg = receipt.getTotalHydrogenConsumedMassKg();
double hydrogenSulfideKg = receipt.getHydrogenSulfideProducedMassKg();
double ammoniaKg = receipt.getAmmoniaProducedMassKg();

On that 1000 kg basis, the receipt returns 995.489447979 kg liquid product, removes 4.071819458 kg sulfur and 1.085174106 kg nitrogen, consumes 1.136701836 kg H2, produces 4.327807878 kg H2S and 1.319445979 kg NH3, and achieves 15 ppm sulfur and 10 ppm total nitrogen. Total-mass, sulfur, and nitrogen residuals are zero within floating-point tolerance.

Use calculateForAssay(...) to read both bulk attributes without mutating the assay, its cuts, or the thermodynamic system.

Provenance and engineering boundary

The public DOE SPR/OEDI Big Hill comprehensive assay supplies the qualified sulfur and total-nitrogen basis.
The existing sulfur receipt documents the EIA and AIChE hydrotreating basis and the NIST H2S molecular weight.
The existing nitrogen receipt documents the AIChE nitrogen-to-ammonia basis and NIST ammonia molecular weight.

The source workbooks and public references are cited, not redistributed. Engineers must select targets and H2/S and H2/N assumptions for the intended screen. Process-design claims require independently validated species, reaction, feed, reactor, separation, recycle, operating-condition, yield, and product-quality models.