On-Line Monitoring of Biofilm Accumulation on Graphite-Polypropylene Electrode Material Using a Heat Transfer Sensor

Biofilms growing on electrodes are the heart piece of bioelectrochemical systems (BES). Moreover, the biofilm morphology is key for the efficient performance of BES and must be monitored and controlled for a stable operation. For the industrial use of BES (i.e., microbial fuel cells for energy production), monitoring of the biofilm accumulation directly on the electrodes during operation is desirable. In this study a commercially available on-line heat transfer biofilm sensor is applied to a graphite-polypropylene (C-PP) pipe and compared to its standard version where the sensor is applied to a stainless-steel pipe. The aim was to investigate the transferability of the sensor to a carbonaceous material (C-PP), that are preferably used as electrode materials for bioelectrochemical systems, thereby enabling biofilm monitoring directly on the electrode surface. The sensor signal was correlated to the gravimetrically determined biofilm thickness in order to identify the sensitivity of the sensor for the detection and quantification of biofilm on both materials. Results confirmed the transferability of the sensor to the C-PP material, despite the sensor sensitivity being decreased by a factor of approx. 5 compared to the default biofilm sensor applied to a stainless-steel pipe.

Passivation of Recirculating Open Water Cooling Systems Using New Organic Passivator

It is well know that recirculating open cooling water system at metal/ water surface contact appear frequent corrosion products, like scales, foaling and material losses which are have great effect on cooling process. Passivation helps to maintain clean heat transfer surface by inhibiting oxides scales through creating outer passive layer. Passivators are substances which usually have a sufficiently high equilibrium potential and sufficiently low over potential decrease corrosion rate on attainment of passivity. One of the most popular passivator is organic phosphate Phosphinosuccinic oligomer C15H14O4P component (PSO) The study of passivation of carbon steel pipe line in recirculating open cooling water system was the aim of this present work. Maximum efficiency of passivator was determined and surface morphology were investigated using optical, scanning microscopy, phase analysis of the formed protective layer was exam by XRD and EDX. Corrosion in running water with and without PSO at 2 m3/hr flow rate was investigated using corrosion coupon rack. It was found that 200 ppm (PSO) decreases corrosion rate of carbon steel pipe in 3.5% NaCL solution from 23 to 7 mpy in stagnate water corrosion testing, while in running water in 3.5% NaCL solution it decreases from 45 to 18 mpy. XDR showed that the protective layer due to passivation is mainly Magnetite (Fe3O4) compound.

Development of an Eddy Current Test Configuration for Welded Carbon Steel Pipes under the Change in Physical Properties

Carbon steel pipe is used in various industries, including nuclear power plants. Due to the daily cyclic operation of the pipe over time, environmental influences, and extreme working conditions, the probability of developing small fine cracks in the welded areas of the pipes increases. For that reason, it requires earlier assessment, and providing adequate inspection and evaluation of the weld area of the pipes used in such an installation is crucial to increase the safety level. In this paper, two different probe configurations were used to assess the integrity of the girth weld of the SA106 carbon steel pipe welded by gas tungsten arc welding. The conventional eddy current probe was initially used, but as it had some limitations, a new probe configuration was proposed to overcome these constraints. Numerical simulations using the finite element method were performed, based on the real measurement of the physical properties of the specimen, to complement the experimental data. In addition, the experimental results were successfully reproduced by the simulations. Simulation and experimental results show that the proposed probe configuration allows adequate inspection.

Guided Wave Transducer for the Locating Defect of the Steel Pipe Based on the Weidemann Effect

The electromagnetic guided wave transducer has been widely used in pipeline detection in recent years due to its non-contact energy conversion characteristics. Based on the Weidemann effect, an electromagnetic guided wave transducer that can realize the locating defect of the steel pipe was provided. Firstly, the principle of the transducer was analyzed based on the Weidemann effect. The basic structure of the transducer and the basic functions of each part were given. Secondly, the key structural parameters of the transducer were studied. Based on the size of the magnets and the coils, a protype electromagnetic guided wave transducer based on Wiedemann effect was developed. Finally, the experiments were carried out on the steel pipe with a defect using the developed transducer. The results show that the transducer can actuate and receive the T(0,1) and T(1,1) modes in the steel pipe. The axial positioning of the defect is located by moving the transducer axially. The circumferential positioning of the defect is located by rotating the transducer. Additionally, missed detection can be effectively avoided by rotating the transducer.