Pump Capital Cost

The capital cost for pumps can be estimated using the power-law relation as shown in Equation (25), where the relevant size parameter is the power of the pump:

$$C\_{\text{pump}} = k\_{\text{p}} (\text{power of pump})^{n\_{\text{p}}} \tag{26}$$

The cost correlation for general-purpose-single and two-stage-single-suction centrifugal pumps discussed in Perry, et al. [21] was used in this study to calculate the pump capital cost. This relation is as follows:

$$C\_{\text{pump}} = I \times f\_1 \times f\_2 \times L \times 81.27 \times \left(Q \times P\right)^{0.4} \tag{27}$$

in which

*I*: a cost index ratio for updating the cost to the recent year *f* 1: an adjust factor for pump construction material *f* 2: an adjust factor for suction pressure range *L*: a factor used to incorporate labor costs *Q*: flow capacity of the pump [m<sup>3</sup>/h] *P*:pressureoutletofthepump[kPa]

The cost index, *I* in Equation (27), can be referred to as the chemical engineering (CE) index and obtained from "Chemical Engineering" magazine. The values of CE index of several years were also tabulated in [22]. The cost index *I* calculated in this study is 2.4 to update the pump cost.

Usually, 40% of the cost is required for labor to install manufactured equipment [23], thus *L* = 1.4.The factors *f* 1 and *f* 2 can be found in [21]. For the application in food industries, the material was set to stainless steel, indicating that *f* 1 = 1.5. Because the operating pressure of most UF and MF applications are below 10 bar (1 MPa), *f* 2 = 1.0 was used in this study.

In the system configuration used in this study, the size factor ( *Q* × *P* in Equation (27)) of the two pumps (feed pump and recirculation pump) is calculated as

$$\text{pump} \times \text{size} = (F + Q) \times P\_{\text{i}} \tag{28}$$

## Capital Cost of Other Equipment

In membrane applications, the membrane area required is the most significant factor which determines the size of the plant [24]. Therefore, the membrane area should be the size parameter used in power-law correlation expression for the estimation of the capital cost of various components.

Sethi [25] segregated nonmembrane equipment and facilities, excluding the pumps which have already been evaluated in Pump Capital Cost, into four main categories: (1) pipes and valves; (2) instruments and controls; (3) tanks and frames; and (4) miscellaneous. The author investigated different sources of data and proposed the calibrated cost correlation for various membrane system components as the following equations:
