Synthetic solid oxide sorbents for CO2 capture: state-of-the art and future perspectives

Carbon capture is an important and effective approach to control the emission of CO2 from point sources such as fossil fuel power plants, industrial furnaces and cement plants into the...

Development of a Pipe Crawler Inspection Tool for Fossil Energy Power Plants

Fossil fuel power plants are complex systems containing multiple components that create extreme environments for the purpose of extracting usable energy. Failures in the system can lead to increased down time for the plant, reduction of power and significant cost for repairs. In the past, inspections and maintenance of the plant's superheater tubes has been predominantly manual, laborious, and extremely time consuming. This is due to the pipe's small diameter size (between 1.3 and 7.6 cm) and the coiled structure of the tubing. In addition, the tubes are often stacked close to each other, limiting access for external inspection. Detection of pipe degradation, such as increased levels of corrosion, creep, and the formation of micro-cracks is possible using standard non-destructive evaluation (NDE) methods, including ultrasonic, radiography and electromagnetic methods. However, when the access to the sub-systems is limited or the configuration of the structure is prohibitive, alternative methods are needed for deploying the NDE tools. This research effort considers a novel robotic inspection system for the evaluation of small pipes found in typical boiler superheaters that have limited access. The pipe crawler system is an internal inspection device that can potentially navigate through the entire pipe length using linear actuators to grip the walls and inch along the pipe. The modular nature of the system allows it to traverse through straight sections and multiple 90-degree and 180-degree bends. The crawler is also capable of providing visual inspections, ultrasonic thickness measurements, and generating inner diameter surface maps using LiDAR (light detection and ranging). Ultimately, the development of this robotic inspection tool can provide information regarding the structural integrity of key pipeline components in fossil fuel power plants that are not easily accessible

Air Pollutant Emission Abatement of the Fossil-Fuel Power Plants by Multiple Control Strategies in Taiwan

This study is an investigation of air pollutant emission abatement in the electricity generation sector from fossil-fuel power plants in Taiwan in 2014 and 2018. PM concentrations are determined by the results of regular tests, while SOx and NOx are determined by continuous emission monitoring systems (CEMS) of flue gas from power plants. The results indicate that electricity generation from fossil-fuel power plants increased by 13.8% from 2014 to 2018. However, emissions of air pollutants from fossil-fuel power plants declined during this period. The results indicate that the annual emissions of SOx, NOx, and PM were 40,826, 59,196, and 5363 tons per year (TPY), respectively, in 2014. The emissions decreased to 30,097 TPY (28% reduction) for SOx, 48,530 TPY (18% reduction) for NOx, and 4496 TPY (16% reduction) for PM in 2018. The ensemble mean values of each air pollutant emission factor also decreased significantly. SOx emissions decreased from 0.2443 to 0.1583 mg/kWh (35% reduction). NOx emissions decreased from 0.3542 to 0.2552 g/kWh (28% reduction). PM emissions decreased from 0.0321 to 0.0236 mg/kWh (26.5% reduction). The results indicated that phasing out of high-pollutant generating units and switching the fuel from coal to natural gas could abate the emissions of SOx and PM, and NOx emissions could be abated by introducing control devices. In addition, new power generation sectors will be constructed and equipped with ultra-low emission control systems to reduce air pollution and create a cleaner and healthier electricity generation system in Taiwan.

Experimental Study of a Lab-Scale Organic Rankine Cycle System for Heat and Water Recovery from Flue Gas in Thermal Power Plants

Fossil fuel power plants can cause numerous environmental issues, owing to exhaust emissions and substantial water consumption. In a thermal power plant, heat and water recovery from flue gas can reduce CO2 emissions and water demand. High-humidity flue gas averts the diffusion of pollutants, enhances the secondary transformation of air pollutants, and leads to smog weather; hence, water recovery from flue gas can also help to lessen the incidence of white plumes and smog near and around the power plant. In this study, a lab-scale system for heat and water recovery from flue gas was tested. The flue gas was initially cooled by an organic Rankine cycle (ORC) system to produce power. This gas was further cooled by an aftercooler, using the same working fluid to condense the water and condensable particulate matter in the flue gas. The ORC system can produce approximately 220 W of additional power from flue gas at 140 °C, with a thermal efficiency of 10%. By cooling the flue gas below 30–40 °C, the aftercooler can recover 60% of the water in it.

Development of an Innovative Inspection Tool for Superheater Tubes in Fossil Fuel Power Plants

Fossil fuel power plants are complex systems containing multiple components that require periodic health monitoring. Failures in these systems can lead to increased downtime for the plant, reduction of power, and significant cost for repairs. Inspections of the plant’s superheater tubes are typically manual, laborious, and extremely time-consuming. This is due to their small diameter size (between 1.3 and 7.6 cm) and the coiled structure of the tubing. In addition, the tubes are often stacked close to each other, limiting access for external inspection. This paper presents the development and testing of an electrically powered pipe crawler that can navigate inside 5 cm diameter tubes and provide an assessment of their health. The crawler utilizes peristaltic motion within the tubes via interconnected modules for gripping and extending. The modular nature of the system allows it to traverse through straight sections and multiple 90° and 180° bends. Additional modules in the system include an ultrasonic sensor for tube thickness measurements, as well as environmental sensors, a light detecting and ranging (LiDAR) sensor, and camera. These modules utilize a gear system that allows for 360° rotation and provides a means to inspect the entire internal circumference of the tubes.