Printable diagrams and data tables
Ten kinds of graph paper, drawn at true scale for A4 or Letter, blank or with the equilibrium already on them — plus every number behind every curve, as a table you can download.
Graphical construction is still the fastest way to understand a separation, and it needs paper. Everything here prints at exactly the size it claims, so a distance measured with a ruler means what you think it means. Every curve is generated from the data tabulated further down this page — nothing is traced from a textbook, and every source is named.
The sheet builder
x – y equilibrium diagram
Pick a system, or leave it blank and draw the curve yourself. Everything prints at true scale.The numbers behind this sheet
Reference data tables
Every curve on this page is computed from one of these. Each table has a CSV button; the source is stated underneath, and where a number is a correlation rather than a measurement it says so.
Antoine constants and thermal data
log₁₀ psat[mmHg] = A − B/(T[°C] + C). Heat capacities and latent heats are constants taken at the normal boiling point and are used for the H–x–y sheet only. Standard tabulated values as used throughout Chapters 2–5.
van Laar parameters
ln γ₁ = A₁₂ [A₂₁x₂/(A₁₂x₁ + A₂₁x₂)]², ln γ₂ = A₂₁ [A₁₂x₁/(A₁₂x₁ + A₂₁x₂)]². Two parameters per pair, fitted to azeotropic or activity data; adequate for teaching, not for design. A negative pair means negative deviation from Raoult's law.
Henry constants for gases in water
Distribution coefficients — acetic acid out of water
Relative volatilities — the light-alkane feed
Adsorption isotherms — benzene on silica gel
Representative membrane permeabilities
Column properties — the propylene–propane splitter
How to use these sheets
Choose the paper size that matches your printer, press Print this sheet, and in the print dialogue set the scale to 100 % (not "fit to page") and margins to none. The plot square then measures exactly what the sheet says it does, so a lever-rule distance taken with a ruler is a real ratio. If your browser insists on adding margins, download the SVG and print that instead.
The point of a blank grid is that you draw the equilibrium curve yourself from a table — that is the step where the data stops being abstract. Draw it, do the construction, and only then come back and generate the same sheet with the curve on it to see how close you were. Every sheet that can be blank has a blank grid option at the top of its system list.
The ideal binaries are computed from Raoult's law and Antoine constants; the non-ideal ones from a two-parameter van Laar fit. Both are teaching models. Where measured data exists — ethanol–water and methanol–water — use the tabulated version instead, and notice how far the van Laar curve sits from it near the azeotrope. The membrane and enthalpy tables are order-of-magnitude only, and say so. Nothing on this page is a substitute for a measured data set or a validated property package.
- x–y and T–xy: building a T–xy diagram2a §2.6 in Chapter 2a, the flash of Chapter 3, and the McCabe–Thiele construction4a §4.6 in Chapter 4a.
- H–xy: the Ponchon–Savarit work behind constant molal overflow4a §4.4 — the diagram that shows you what CMO throws away.
- Mole-ratio X–Y: solute-free coordinates6 §6.3 for the absorber and stripper of Chapter 6, and the immiscible extraction cascade of Chapter 77 §7.2.
- Ternary grids: the right-triangle diagram7 §7.4, the lever rule and the difference point.
- Isotherm and log–log paper: the adsorption isotherm8 §8.3 and its three models.
- Gilliland: the Gilliland correlation5 §5.5 closing the Fenske–Underwood–Gilliland recipe.
- Fair chart: the flooding velocity10 §10.4 and the column diameter that follows from it.