**6. Cost imposed due to fouling**

Apart from the high cost of heat exchanger fouling, very few work have been reported to accurate determine economic penalties causes by fouling. Therefore, these attribute cost to difference aspect of heat exchanger design and operation. However, reliable knowledge of fouling economics is desirable in order to evaluate the cost efficiency of various mitigation strategies [26, 27]. The total fouling-related costs involve the following:

#### **1. Capital expenditure**

Excessive surface area required to overcome the heavy fouling conditions, costs for stronger foundation, provision for extra spaces and increased transportation and installation costs.

#### **2. Energy costs**

Costs for extra fuel required if fouling leads to extra fuel burning in heat exchanging equipment to overcome the effect of fouling.

#### **3. Maintenance costs**

Costs for removal of fouling deposits, costs for chemicals or other operating costs for antifouling devices.

#### **4. Cost of production loss**

Planned or unplanned plant shutdowns due to fouling in heat exchangers can cause large production losses. These losses are often considered to be the main cost of fouling and very difficult to estimate.

#### **5. Extra environmental management cost**

Cost for disposing large amount of chemical/additives used for fouling mitigation.


**Table 1.** Estimated fouling costs incurred in some countries (1992 estimation) [28].

Huge fouling costs are reported in different countries. Steinhagen et al. reported about the fouling costs in term of GNPs for some countries as presented in **Table 1**.
