Impact of Corrosion in Carbon Steel Pipeline of Marine Wastewater Outfall during Electric Power Generation

Municipal wastewater is discharged into the sea after undergoing adequate/suitable treatment process. Carbon steel pipes are the most commonly used subsea metal pipes to transport wastewater deep under the sea. These carbon steel pipes experience corrosion which leads to an increased surface roughness. Pipe surface roughness determines the pressure losses as a result of the friction during the flow of fluid within the pipeline. Hence, pressure losses lead to a reduction in fluid volumetric flow rate. At the outlet of the carbon steel pipeline, a significant amount of energy can be generated from discharged wastewater. It can be generated using hydrokinetic turbine coupled to a permanent magnet synchronous generator (PMSG). Hence, the aim of this paper is to investigate the potential impact of corrosion formation within the carbon steel pipe during electric power generation. MATLAB/Simulink tool has been used to develop the model. Hence, different absolute roughness's have been modelled to analyse the potential impact. When the absolute roughness is increased from 44 micro meters to 60 micro meters, this has led to a 0.44% decrease in generated voltage. Hence, both the rotational speed and frequency of the PMSG were also reduced by 5.4% and 3.6%, respectively.