392
N. T. Mathew et al.
25.3.2 Economic Impacts
This section describes the major economic impacts due to biofouling in marine and
coastal heat exchangers. The impacts are classified into four categories. A cumulative
model of the economic impacts is presented in Fig. 25.2.
Category 4: Reduced heat exchanger efficiency and subsequent costs
From an economic perspective, the biggest problem caused by marine heat exchanger
biofouling is the loss in production due to the reduction in heat transfer efficiency.
For big industries like refineries and petrochemical plants, energy loss due to reduced
heat transfer could result in a subsequent loss in their overall production. Additional
energy has to be supplied to compensate for the energy loss. Fossil fuels are the
commonly used energy source and with the increase in biofouling, the consumption
of fossil fuels also increases. This will increase production costs (Hansen 2018).
To avoid these production losses and the costs associated with that, the heat
exchanger users will try to increase the flow inside the heat exchanger. To increase
the flow, higher capacity pumps have to be installed. This causes an increase in pump
purchasing costs (Hansen 2018; Kronholm 2018). The increase in the pump cost is
highly variable depending on the severity of biofouling in each case (Hansen 2018).
Hence, it is difficult to provide an average range of values (Hansen 2018). The higher
capacity pumps will result in high energy consumption (Kronholm 2018). As a result,
the energy costs (mostly electrical energy) will also become higher with the increase
in biofouling (Kronholm 2018). Thus resulting in a significant increase in the overall
operational expenditure.
Category 5: Biofouling corrosion and subsequent costs
If the biofouling deposits formed on the heat exchanger surfaces are not timely
removed, the fouling deposits will erode the surface. This affects the proper
functioning of the heat exchanger and further decreases the heat exchanger life
expectancy. Therefore, if left unchecked, biofouling will result in early heat
exchanger replacement costs (Hansen 2018; Kronholm 2018; Bertilsson 2018).
Further, biofouling corrosion will lead to leaks and call for unscheduled repair or
maintenance. This will not only increase the maintenance expenditure for the enduser but also increase the operational expenditure due to unscheduled equipment
downtime and subsequent loss of production (Hansen 2018). Frequent repair and
maintenance of the heat exchanger will also reduce the equipment life and thereby
leads to increased depreciation costs.
Category 6: Biofouling removal or mitigation costs
Therefore, to reduce the production loss and the additional operational & maintenance expenditure, the heat exchanger users will try to remove biofouling from
the heat exchanger surface. There are both online and offline biofouling prevention
techniques. Accordingly, there are various costs associated with these techniques.
N. T. Mathew et al.
25.3.2 Economic Impacts
This section describes the major economic impacts due to biofouling in marine and
coastal heat exchangers. The impacts are classified into four categories. A cumulative
model of the economic impacts is presented in Fig. 25.2.
Category 4: Reduced heat exchanger efficiency and subsequent costs
From an economic perspective, the biggest problem caused by marine heat exchanger
biofouling is the loss in production due to the reduction in heat transfer efficiency.
For big industries like refineries and petrochemical plants, energy loss due to reduced
heat transfer could result in a subsequent loss in their overall production. Additional
energy has to be supplied to compensate for the energy loss. Fossil fuels are the
commonly used energy source and with the increase in biofouling, the consumption
of fossil fuels also increases. This will increase production costs (Hansen 2018).
To avoid these production losses and the costs associated with that, the heat
exchanger users will try to increase the flow inside the heat exchanger. To increase
the flow, higher capacity pumps have to be installed. This causes an increase in pump
purchasing costs (Hansen 2018; Kronholm 2018). The increase in the pump cost is
highly variable depending on the severity of biofouling in each case (Hansen 2018).
Hence, it is difficult to provide an average range of values (Hansen 2018). The higher
capacity pumps will result in high energy consumption (Kronholm 2018). As a result,
the energy costs (mostly electrical energy) will also become higher with the increase
in biofouling (Kronholm 2018). Thus resulting in a significant increase in the overall
operational expenditure.
Category 5: Biofouling corrosion and subsequent costs
If the biofouling deposits formed on the heat exchanger surfaces are not timely
removed, the fouling deposits will erode the surface. This affects the proper
functioning of the heat exchanger and further decreases the heat exchanger life
expectancy. Therefore, if left unchecked, biofouling will result in early heat
exchanger replacement costs (Hansen 2018; Kronholm 2018; Bertilsson 2018).
Further, biofouling corrosion will lead to leaks and call for unscheduled repair or
maintenance. This will not only increase the maintenance expenditure for the enduser but also increase the operational expenditure due to unscheduled equipment
downtime and subsequent loss of production (Hansen 2018). Frequent repair and
maintenance of the heat exchanger will also reduce the equipment life and thereby
leads to increased depreciation costs.
Category 6: Biofouling removal or mitigation costs
Therefore, to reduce the production loss and the additional operational & maintenance expenditure, the heat exchanger users will try to remove biofouling from
the heat exchanger surface. There are both online and offline biofouling prevention
techniques. Accordingly, there are various costs associated with these techniques.