Category
Chemical Engineering
Chemical engineering formulas and calculators for reaction kinetics, mass transfer, and process design used in industrial chemical production. Includes reactor sizing, thermodynamic equilibrium, and separation process equations.
34Formulas
3Subcategories
Updated Jul 2026
General
Compressibility Factor (Real Gas)
Z = PV / (nRT)
General
Relative Volatility
alpha_AB = (y_A/x_A) / (y_B/x_B)
General
Gas-Phase Mass Transfer Rate (Two-Film Theory)
N_A = Ky * a * (y - y*)
General
Sensible Heat Duty
Q = m * cp * dT
General
Specific Gravity
SG = rho_substance / rho_reference
General
Newton's Law of Viscosity
tau = mu * (dv/dy)
General
Orifice Meter Flow Rate
Q = Cd * A0 * sqrt(2*dP/(rho*(1-beta^4)))
General
Net Positive Suction Head Available (NPSHa)
NPSHa = (P_suction - P_vapor)/(rho*g) + z - h_f
General
Pump Hydraulic Power
P = rho * g * Q * H / eta
General
Ergun Equation (Packed Bed Pressure Drop)
dP/L = 150*mu*(1-e)^2*v/(e^3*dp^2) + 1.75*rho*(1-e)*v^2/(e^3*dp)
General
Plug Flow Reactor Volume (First-Order Reaction)
V = (F_A0 / k) * ln(1 / (1 - X))
General
CSTR Residence Time (Space Time)
tau = V / v0
General
Reaction Yield
Y = F_product / F_A0
General
Reaction Selectivity
S = F_desired_product / F_undesired_product
General
Reactor Conversion
X = (F_A0 - F_A) / F_A0
General
Dilution Equation
C1 * V1 = C2 * V2
General
Molar Concentration (Molarity)
M = n / V
General
Degrees of Freedom Analysis
DOF = N_unknowns - N_independent_equations
General
Henry's Law (Gas Solubility)
P_i = H * x_i
General
Raoult's Law
P_i = x_i * P_i_sat
General
Distillation Reflux Ratio
R = L / D
General
Prandtl Number
Pr = cp * mu / k
General
Nusselt Number
Nu = h * L / k
General
Heat Exchanger Effectiveness (NTU Method)
epsilon = Q_actual / Q_max
General
Overall Heat Transfer Coefficient
1/U = 1/hi + 1/ho + Rf
General
Heat Exchanger LMTD
LMTD = (dT1 - dT2) / ln(dT1/dT2)
General
Fick's First Law of Diffusion
J = -D * (dC/dx)
General
Antoine Equation (Vapor Pressure)
log10(P) = A - B/(C + T)
General
Darcy-Weisbach Pressure Drop
delta_P = f * (L/D) * (rho * v^2)/2
General
Continuity Equation (Mass Balance)
rho1 * A1 * v1 = rho2 * A2 * v2
Process Design
Bernoulli's Equation
P + ½ρv² + ρgh = const
Process Design
Reynolds Number
Re = ρvD / μ
Kinetics
Arrhenius Equation
k = Ae^(−Ea/RT)
Kinetics
Rate Law for a Reaction
r = k[A]ⁿ