Question

Currently, the two gas pipes are 1m long and 75km long, the same size and length.

However, pipeline A roughly performed coating, other pipeline B performed very high quality coating, followed by Inspected Current Cathodic Protection (ICP) with a system of 100 V, 100 A (10 kW). After 10 years, pipeline A (method potential) is required as a result of the investigation.The current density was 1.72 mA/m^2 and the required current density was 86uA/cm^2. In this case, compare and explain the method efficiency.
(Refer) 1 pipeline total surface area = 235,500 m^2

Answer 1

The method efficiency of coating on pipeline A and B can be compared based on the current density and the required current density.

First, let's calculate the current flowing through each pipeline:

- For pipeline A: The length of pipeline A is 1m. The current density is 1.72 mA/m^2, which means the current flowing through 1m of pipeline A is 1.72 mA.

- For pipeline B: The length of pipeline B is 75km, which is equivalent to 75,000m. To find the current flowing through 1m of pipeline B, we need to convert the required current density from uA/cm^2 to mA/m^2.

- The required current density is 86uA/cm^2, which is equal to 8.6 mA/m^2 (since 1 uA/cm^2 is equal to 0.1 mA/m^2).

- So, the current flowing through 1m of pipeline B is 8.6 mA.

Next, let's calculate the method efficiency of pipeline A compared to the required current density:

- The required current density is 8.6 mA/m^2.

- The current density of pipeline A is 1.72 mA/m^2.

- The method efficiency is the ratio of the current density of pipeline A to the required current density, multiplied by 100% to get the percentage.

- So, the method efficiency of pipeline A is (1.72 mA/m^2 / 8.6 mA/m^2) * 100% = 20%.

In this case, the method efficiency of pipeline A is 20%, which means that the coating method used on pipeline A is only 20% as efficient as the required current density. This indicates that the coating on pipeline A may not be providing adequate protection against corrosion compared to the coating on pipeline B.