Alph - A Little Process Helper

The base version of Alph can be purchased for $19.99 (or currency equivalent) in the Apple App Store. It contains all the features listed below and has VMG's Advanced Peng-Robinson for Natural Gas property package and a selection of basic compounds used in natural gas processing:

C1-C10, iC4, iC5, H2O, CO2, H2S and N2

Additional compounds and property package options can be added by means of purchases made right in the program in the Alph Store.

Most of these options are quite inexpensive, but the Alph Professional option, which includes over 5600 compounds and the NRTL property package, is $499.99. This may seem expensive for an IOS device, but it is a fraction of the price of anything remotely comparable on a PC.

There is also a separate free version called Alph Jr available in the Apple App Store. This has all the features of Alph, but is limited to just 10 compounds, C1-C10, and does not have the in application store for purchasing additional options. This is intended both as a free introduction to Alph's features and for instructional and learning purposes.

Calculate Fluid Properties


Alph can perform two and three phase flashes for either normal or retrograde conditions. The types of flashes available are:

  • Temperature - Pressure
  • Temperature - Enthalpy
  • Temperature - Vapour fraction
  • Pressure - Enthalpy
  • Pressure - Entropy
  • Pressure - Vapour fraction
  • Bubble Point Temperature
  • Bubble Point Pressure
  • Dew Point Temperature
  • Dew Point Pressure

Phase envelopes

Phase Envelopes

Two phase envelopes can be calculated with optional quality lines. The graph can be zoomed in and out by pinching and dragged around to display the temperature and pressure under the cross hairs.

Hydrate Conditions

Hydrate Conditions

Hydrate formation temperature or pressure can be calculated with the this tool. If water is not present in the fluid (note water is not available in the base version or Alph Jr), then free water will be assumed. If water is present, its quantity will be taken into account as will the presence of alcohol or glycol inhibitors.

Hydrate Conditions

Function Solver

Solves single or multiple formulas, including array formulas, which represent f(x)=0 are solved with x being the output values of the tool. This allows both simple single value adjustments as well as complex multiple recycle problems to be addressed.

Fluid Interactions

Fluid Interactions

Alph has a simple formula system, which allows fluids to be defined in terms of one another, allowing for surprisingly sophisticated calculations. The fluid in the screen shot is being defined with its pressure being equal to the feed fluid minus two times a pressure drop variable (Alph has three main types of objects: fluids, variables and tools). The flow and composition are being set equal to the feed fluid vapour phase.

Adding a Tool


Alph includes a number of standard tools:

Spreadsheet Report


You can save and load cases from the paste board, which allows you to mail cases to other Alph users. You can also save and mail yourself spreadsheet reports and phase envelope results. Alph also supports transferring cases to your PC using iTunes File Sharing.

Case files are in human readable JSON, while reports are either tab or comma separated (CSV).


Alph can calculate the following fluid properties:

VfMolar vapour fraction (phase fraction when viewing phases)
FMolar flow rate
HSpecific molar enthalpy
SSpecific molar entropy
QEnergy flow
MwMolecular weight
ZFactorCompressibility factor
VolumeSpecific molar volume
MassDensityMass density
StdLiqDensityStandard liquid density
KinematicViscosityKinematic viscosity
ThermalConductivityThermal conductivity
SurfaceTensionSurface tension
CpConstant pressure specific molar heat capacity
CvConstant volume specific molar heat capacity
GibbsFreeEnergyGibbs free energy
LowHeatingValueLower heating value
MassFMass flowrate
MassHSpecific mass enthalpy
MassSSpecific mass entropy
MassCpConstant pressure specific mass heat capacity
MassCvConstant volume specific mass heat capacity
RxnBasisCorrection to enthalpy to calculate heats of reaction
XComposition in mole fractions
MassFractionComposition in mass fractions
MwtArrayCompound molecular weights