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Direct Methanol Synthesis (CO2 + H2) — Screening Mass Balance, Sizing & Cost Curve (No Gas Compression)

Screening-level direct methanol synthesis calculator: input methanol output, compute H2/CO2 needs, water co-product, key equipment sizing, and CAPEX/OPEX via a power-law cost curve (compression excluded).

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alexi

I do low-carbon energy stuff for 10 years & build things I wish existed.

Inputs

Net saleable methanol production target at battery limit on a nameplate annual basis (kta = 1000 t/year). The model converts to daily, hourly, and annual production. Minimum is 100 kta for cost curve validity.

min 100 · max 500 · step 1 · kta

Fraction of the year the plant operates at nameplate equivalent. Used to compute load hours and annualized production/consumption.

min 10 · max 100 · step 1 · %

Used only to annualize CAPEX via the capital recovery factor (CRF).

Amortization period for annualizing CAPEX via CRF (not a detailed depreciation/tax model).

years

Feedstock

Delivered H2 price to the synthesis block battery limit (compression excluded from this calculator’s scope).

EUR/kg

CO2 supply price. Can be negative to represent a credit (e.g., paid to take CO2), depending on contract/accounting.

EUR/t

Cost of supplied heat/steam (e.g., natural gas boiler steam or imported steam).

EUR/GJ

Electricity price for pumps, controls, and auxiliaries. Gas compression electricity is excluded by scope.

EUR/MWh

Results

Methanol (net product)

User-defined net saleable output at battery limit (nameplate day basis).

…kg/day

Methanol (net product)

Hourly equivalent of the net nameplate output.

…kg/hour

Methanol (net product)

Annual net production accounting for capacity factor.

…kg/year

Hydrogen feed required

Daily H2 requirement at nameplate.

…kg/day

Hydrogen feed required

Hourly H2 requirement (gross synthesis basis, incl. utilization losses).

…kg/hour

Hydrogen feed required

Annual H2 requirement accounting for capacity factor via load hours.

…kg/year

CO2 feed required

Daily CO2 requirement at nameplate.

…kg/day

CO2 feed required

Hourly CO2 requirement (gross synthesis basis, incl. utilization losses).

…kg/hour

CO2 feed required

Annual CO2 requirement accounting for capacity factor.

…t/year

Water co-product

Annual water produced accounting for capacity factor.

…kg/year

Water co-product

Stoichiometric water produced (co-product stream), hourly basis.

…kg/hour

Electricity demand (excl. compression)

Annual electricity use for synthesis block utilities, excluding gas compression.

…MWh/year

Heat demand (excl. compression)

Annual process heat/steam demand for synthesis + separation, excluding gas compression.

…GJ/year

Methanol losses

Difference between gross synthesis output and net saleable product (modeled yield/handling losses).

…kg/year

Hydrogen not converted (proxy)

Indicative annual H2 lost to purge/inefficiencies implied by hydrogen utilization factor.

…kg/year

CO2 not converted (proxy)

Indicative annual CO2 lost to purge/inefficiencies implied by CO2 utilization factor.

…kg/year

Equipment purchase cost (EPC)

Purchased equipment only; excludes installation, indirects, owner’s costs.

…EUR

Installed plant cost (installed)

Equipment purchase plus installation-related direct costs (bulk materials, labor).

…EUR

Total project CAPEX (TPC)

Installed plant cost plus indirects/owner’s costs via a multiplier.

…EUR

Annual feedstock cost

Annual cost of H2 and CO2 (CO2 price may be negative for credit).

…EUR/year

Annual utilities cost

Electricity + heat cost, excluding compression power.

…EUR/year

Annual fixed O&M

Fixed O&M estimated as a fraction of installed plant cost, scaled with size.

…EUR/year

Annual catalyst replacement (average)

Average annualized cost of catalyst replacement based on interval.

…EUR/year

Total annual cost

Sum of annualized CAPEX, O&M, replacement, feedstocks, and utilities.

…EUR/year

Indicative unit cost of methanol

Screening unit cost = total annual cost divided by annual net methanol.

…EUR/kg

Cost

Design

Number of process trains

Estimated parallel trains based on a maximum single-train capacity heuristic.

…

Reactor diameter (per train)

Indicative cylindrical reactor internal diameter derived from catalyst volume and L/D ratio.

…m

Reactor height (per train)

Indicative internal height using fixed L/D ratio.

…m

Plot space requirement

Indicative plot area including an integration margin.

…m2

About

Calculator context

Introduction

This calculator provides a pre-feasibility (screening) estimate for a direct methanol synthesis (DMS) block converting CO2 + H2 → CH3OH + H2O, where the user specifies the methanol production rate and the model returns feedstock needs (H2, CO2), co-product water, selected equipment sizing indicators, and CAPEX/OPEX based on a power-law costing curve. The scope follows common techno-economic screening practice (IEA/IRENA/NREL-style approaches) and explicitly excludes gas compression energy and compression equipment per the operating constraint.

Methodology

The model is organized as (i) availability/part-load effects, (ii) stoichiometric mass balance with utilization losses, (iii) simplified sizing relationships, and (iv) cost curve + annualization.

Key calculations (variables defined in-line; all costs in EUR):

  • Operating time
    • load_hours = hours_per_year × capacity_factor
    • load_penalty = clamp(1 + penalty_coeff × (1 − capacity_factor), 1, max_penalty)
  • Electricity and heat intensity (screening)
    • effective_consumption = specific_consumption × load_penalty (specific_consumption in kWh/kg MeOH)
    • annual_electricity = effective_consumption × annual_gross_meoh / 1000 (MWh/y)
    • annual_heat = base_specific_heat × (1 + heat_loss_fraction) × load_penalty × annual_gross_meoh / 1000 (GJ/y)
  • Mass balance (CO2 hydrogenation stoichiometry)
    • CO2 + 3H2 → CH3OH + H2O
    • Feed requirements apply utilization factors (purge/recycle inefficiencies): feed = stoich / utilization
    • Product loss is represented by product_loss_fraction (net saleable vs gross synthesis)
  • Costing curve and annualization (screening)
    • specific_capex_scaled = clamp(capex_ref × (capacity/capacity_ref)^k, min, max)
    • equipment_purchase_cost = specific_capex_scaled × capacity
    • installed_plant_cost = equipment_purchase_cost × install_factor
    • total_project_capex = installed_plant_cost × indirect_owner_factor
    • CRF = (r × (1 + r)^n) / ((1 + r)^n − 1) (standard capital recovery factor)

Cost-curve structure and scaling practice are consistent with standard chemical engineering cost scaling references (e.g., Towler & Sinnott; Peters & Timmerhaus) and are commonly used in IEA/IRENA/NREL-style screening TEAs.

Applications

  • Business developer: quickly size H2 and CO2 supply contracts for a target methanol offtake and quantify the water co-product.
  • Project development: compare CAPEX sensitivity to plant scale (single vs multiple trains) and screen feasibility before detailed FEED.
  • Commercial/strategy: assess exposure of unit cost (EUR/kg MeOH) to H2 price or CO2 price under a fixed capacity factor (screening only).

Model

112 variables — inputs, calculations and outputs, with their dependencies.

112 variables shown of 112
VariableValueUnitDepends on
100kta—
90%—
4EUR/kg—
80EUR/t—
60EUR/MWh—
8EUR/GJ—
0.08ratio—
20years—
VariableFormulaUnitDepends on
if((if(<=,,)+if((*0.01)<,,)+if((*0.01)>,,)+if(<,,)+if(<=,,)+if(<,,)+if(<,,)+if(<,,))>,,)bool
*(*0.01)hours/year
clamp(+*(-(*0.01)),,)—
/max((-),)kg/hour
*kg/year
kWh/kg
*kWh/kg
*(+)MJ/kg
*MJ/kg
*(/max((+),))GJ/year
*kg/hour
*kg/hour
*kg/year
/max(,)t/day
/max(,)t/day per train
/max(,)kg/hour per train
/max(,)kg per train
/max(,)m3 per train
/max((-),)m3 per train
clamp(*(/max(,))^,,)EUR per (t/day)
clamp(*(/max(,))^,,)—
*EUR/year
**EUR
*EUR/year
*EUR/year
*EUR/year
*EUR/year
(*(+)^)/max(((+)^-),)—
*EUR/year
VariableFormulaUnitDepends on
*kg/day
/max(,)kg/hour
*kg/year
-kg/year
*/max(,)MWh/year
*/max(,)GJ/year
*kg/hour
/max(,)kg/hour
/max(,)kg/hour
*kg/day
*kg/day
*kg/year
/max(,)t/year
*kg/year
(-)*kg/year
(-)*kg/year
ceil(/max(,))—
(*/max((*),))^m
*m
**(/max(,))^m2
*EUR
*EUR
*EUR
*EUR/year
/max(,)EUR/year
+EUR/year
+EUR/year
+++++EUR/year
/max(,)EUR/kg

Assumptions

46 assumptions used in the calculations

  • Prevents division-by-zero and improves robustness for edge cases during screening.

    Market range 1e-9 to 1e-6 (typical numerical guard values)

    0.000001
    Numerical stability constant for division guards.

  • Avoids inline magic numbers in validation logic.

    Market range 0

    0
    Numeric constant.

  • Avoids inline magic numbers in formulas (except CRF pattern).

    Market range 1

    1
    Numeric constant.

  • Used to derive reactor diameter from volume and L/D ratio.

    Market range 0.333333

    0.333333
    Numeric constant for cubic root exponent.

  • Used in cylinder volume rearrangement (4V/(pi*L/D)).

    Market range 4

    4
    Numeric constant.

  • Ensures the part-load penalty cannot improve performance below nameplate.

    Market range 1

    1
    Modeling convention.

  • Used to convert capacity factor to load hours.

    Market range 8760

    8760hours/year
    Calendar year hours.

  • Converts daily nameplate to hourly rate.

    Market range 24

    24hours/day
    Time conversion.

  • Converts kWh to MWh for annual electricity outputs and costs.

    Market range 1000

    1000kWh/MWh
    Unit conversion.

  • Converts MJ to GJ for annual heat outputs and costs.

    Market range 1000

    1000MJ/GJ
    Unit conversion.

  • Converts kg to tonnes for CO2 and capacity representation.

    Market range 1000

    1000kg/t
    Unit conversion.

  • Captures higher specific auxiliary consumption at lower capacity factors (controls, recycles, thermal losses).

    Market range 0.05 to 0.3 (dimensionless)

    0.15
    Screening assumption for part-load performance penalty.

  • Prevents extreme part-load penalty inflation for very low CF in a screening model.

    Market range 1.1 to 1.5

    1.25
    Model clamp bound.

  • Represents net-vs-gross losses from purge, off-spec, storage/handling, or incomplete recovery in separation.

    Market range 0.0 to 0.03

    0.01fraction
    Screening yield/handling loss factor.

  • Accounts for H2 not converted due to purge or recycle inefficiency without explicit recycle simulation.

    Market range 0.9 to 0.99

    0.97fraction
    Screening recycle/purge utilization factor.

  • Accounts for CO2 not converted due to purge or recycle inefficiency without explicit recycle simulation.

    Market range 0.9 to 0.995

    0.98fraction
    Screening recycle/purge utilization factor.

  • 3 mol H2 per 1 mol MeOH; converted using molar masses.

    Market range Fixed by chemistry

    0.1887kg H2 / kg MeOH
    Stoichiometry-derived mass ratio for CO2 + 3H2 → CH3OH + H2O.

  • 1 mol CO2 per 1 mol MeOH; converted using molar masses.

    Market range Fixed by chemistry

    1.373kg CO2 / kg MeOH
    Stoichiometry-derived mass ratio for CO2 + 3H2 → CH3OH + H2O.

  • 1 mol H2O per 1 mol MeOH; converted using molar masses.

    Market range Fixed by chemistry

    0.562kg H2O / kg MeOH
    Stoichiometry-derived mass ratio for CO2 + 3H2 → CH3OH + H2O.

  • Represents pumps, instrumentation, recycles, and general auxiliaries for synthesis + separation; compression excluded by scope.

    Market range 0.05 to 0.3 kWh/kg (excluding compression; highly site/process dependent)

    0.1kWh/kg MeOH
    Screening auxiliary electricity intensity (excluding compression).

  • Represents net useful heat duty for separation/purification and process heating.

    Market range 1.0 to 5.0 MJ/kg (process-dependent)

    2.2MJ/kg MeOH
    Screening heat/steam intensity for separation and conditioning (excluding compression).

  • Captures distribution losses and imperfect heat integration at screening stage.

    Market range 0.05 to 0.25

    0.15fraction
    Screening heat loss/inefficiency allowance.

  • Anchor point for the power-law cost curve at screening stage.

    Market range 10 to 2000 t/day (varies by reference study)

    100t/day
    Cost curve reference capacity for scaling.

  • Represents purchased equipment only for the DMS block (excluding compression); used to build a scalable curve for large assets.

    Market range 60000 to 220000 EUR/(t/day) for large chemical processing blocks

    95000EUR per (t/day)
    Screening purchased-equipment specific CAPEX at reference capacity.

  • Typical exponent for chemical process equipment scaling in early estimates.

    Market range 0.5 to 0.8

    0.65
    Economies-of-scale exponent for process plants.

  • Avoids overly optimistic extrapolation to very large scales.

    Market range 50000 to 150000

    60000EUR per (t/day)
    Clamp lower bound for specific CAPEX.

  • Avoids unrealistic cost escalation when extrapolating to very small scales.

    Market range 200000 to 800000

    220000EUR per (t/day)
    Clamp upper bound for specific CAPEX.

  • Converts purchased equipment cost to installed plant cost including bulk materials and installation labor.

    Market range 1.8 to 3.0

    1.2
    AI

  • Adds indirects and owner’s costs as a screening multiplier.

    Market range 1.15 to 1.3

    1.1
    Indirect/owner cost multiplier (installed to total project).

  • Represents staffing, maintenance, insurance, and overhead in a simplified manner.

    Market range 0.012 to 0.045

    0.025fraction of installed cost per year
    Screening fixed O&M fraction at reference scale.

  • Allows modest economies of scale in fixed O&M fraction.

    Market range -0.2 to 0.0

    -0.1
    Screening exponent for O&M fraction vs size.

  • Avoids unrealistic fixed O&M fractions at large scale in screening.

    Market range 0.01 to 0.03

    0.012fraction of installed cost per year
    Clamp lower bound for fixed O&M fraction.

  • Avoids unrealistic fixed O&M fractions at small scale in screening.

    Market range 0.04 to 0.08

    0.045fraction of installed cost per year
    Clamp upper bound for fixed O&M fraction.

  • Covers minor consumables, waste disposal, and routine variable costs not captured elsewhere.

    Market range 0.0 to 0.02 EUR/kg

    0.006EUR/kg MeOH
    Screening variable O&M allowance.

  • Used to estimate number of parallel trains and per-train equipment sizing.

    Market range 50 to 500 t/day per train (project dependent)

    200t/day per train
    Screening heuristic for maximum single-train capacity.

  • Used only for indicative catalyst inventory and reactor sizing; not a kinetic model.

    Market range 0.2 to 1.5

    0.6kg MeOH per kg catalyst per hour
    Screening catalyst productivity for CO2 hydrogenation.

  • Converts catalyst mass to catalyst bed volume for reactor sizing.

    Market range 900 to 1400

    1100kg/m3
    Screening packed-bed catalyst bulk density.

  • Converts catalyst bed volume to reactor internal volume allowance.

    Market range 0.35 to 0.5

    0.4fraction
    Screening void fraction allowance.

  • Used to derive reactor diameter and height from internal volume.

    Market range 2 to 6

    3m/m
    Screening reactor aspect ratio (L/D).

  • Used for cylinder geometry calculations.

    Market range 3.141593

    3.141593
    Mathematical constant.

  • Provides order-of-magnitude site footprint for the DMS block including access and integration allowances.

    Market range 3000 to 50000 m2 at ~100 t/day (varies widely)

    12000m2
    Screening plot area at reference capacity.

  • Captures economies of scale for plot space with increasing throughput.

    Market range 0.5 to 0.9

    0.6
    Footprint scaling exponent.

  • Adds allowance for pipe racks, electrical rooms, access roads, and laydown areas.

    Market range 1.1 to 1.6

    1.3
    Integration margin multiplier.

  • Used to estimate replacement cost magnitude; actual depends on catalyst formulation and vendor contract.

    Market range 10 to 60 EUR/kg

    18EUR/kg
    Screening catalyst cost placeholder.

  • Represents periodic catalyst change-out; used to annualize replacement cost.

    Market range 2 to 6 years

    4years
    Screening catalyst replacement interval.

  • Converts kta (1000 t/year) to kg/day for internal calculations.

    Market range 1000000

    1000000kg/day per kta
    Unit conversion.