The relationship between capital cost and capacity for industrial equipment often follows a power law, known as the scaling law. In this case, the cost-capacity relationship can be described by \( CC = k \times S^\beta \), where \( k \) is a constant and \( \beta \) is the cost-capacity factor.
Step 1: Understanding the Cost-Capacity Factor:
The value of \( \beta \) typically ranges between 0.6 and 0.8 for many types of industrial equipment, representing economies of scale. As the capacity increases, the increase in cost is less than proportional.
Step 2: Rule-of-Thumb for \( \beta \):
The most commonly used rule-of-thumb for \( \beta \) is 0.6, which suggests that as capacity doubles, the capital cost increases by approximately 60%, not doubling.
Consider a process with transfer function: \[ G_p = \frac{2e^{-s}}{(5s + 1)^2} \] A first-order plus dead time (FOPDT) model is to be fitted to the unit step process reaction curve (PRC) by applying the maximum slope method. Let \( \tau_m \) and \( \theta_m \) denote the time constant and dead time, respectively, of the fitted FOPDT model. The value of \( \frac{\tau_m}{\theta_m} \) is __________ (rounded off to 2 decimal places).
Given: For \( G = \frac{1}{(\tau s + 1)^2} \), the unit step output response is: \[ y(t) = 1 - \left(1 + \frac{t}{\tau}\right)e^{-t/\tau} \] The first and second derivatives of \( y(t) \) are: \[ \frac{dy(t)}{dt} = \frac{t}{\tau^2} e^{-t/\tau} \] \[ \frac{d^2y(t)}{dt^2} = \frac{1}{\tau^2} \left(1 - \frac{t}{\tau}\right) e^{-t/\tau} \]
Methanol is produced by the reversible, gas-phase hydrogenation of carbon monoxide: \[ {CO} + 2{H}_2 \rightleftharpoons {CH}_3{OH} \] CO and H$_2$ are charged to a reactor, and the reaction proceeds to equilibrium at 453 K and 2 atm. The reaction equilibrium constant, which depends only on the temperature, is 1.68 at the reaction conditions. The mole fraction of H$_2$ in the product is 0.4. Assuming ideal gas behavior, the mole fraction of methanol in the product is ____________ (rounded off to 2 decimal places).