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*, and Process Energy Management
Published in Barney L. Capehart, William J. Kennedy, Wayne C. Turner, Guide to Energy Management, 2020
Barney L. Capehart, William J. Kennedy, Wayne C. Turner
Data:Compressor size: 75 and 60-kWAverage air temperature before compressor (T1): 30°CAverage air temperature after compressor (T2): 45°CHot air flow rate from 75-kW compressor: 4.750 m3/sOperation hours: 992 h/year (24 h/day, 5 days/week; 4 h/day, 1 day/week; 8 weeks/year)Natural gas cost: €0.1165/m3Efficiency of gas heater: 0.80Percent load on compressor: 75%Ductwork length: 11 m each (22 m for both)
Advanced Fossil Fuel Power Systems
Published in D. Yogi Goswami, Frank Kreith, Energy Conversion, 2017
Exhaust gas from the FR, comprising mainly CO2 (and some H2O as steam), is expanded in the CO2turbine. CO2 turbine exhaust is utilized to heat natural gas in a fuel gas heater. Cooled exhaust gas is sent to the CCS block, which comprises CO2 dehydration and recompression for sequestration. Plant performance is a function of air turbine inlet temperature and cycle pressure ratio. At 1100°C–1200°C and a PR of 10, net efficiencies (including CO2 compression) around 50% have been calculated [131]. At the given parameters, excluding CO2 compression, this corresponds to a CF of 0.75. This CF is about the same as that of an F class GTCC (1400°C TIT with a PR of 16–18)—see Figure 13.19. As such, it should be considered somewhat optimistic.
Gas shielded arc welding (MIG, MAG and TIG)
Published in Andrew Livesey, Alan Robinson, The Repair of Vehicle Bodies, 2018
This gas is used as a shielding gas in the MAG welding process. It is not an inert gas: when it passes through the welding arc there is some breakdown into carbon monoxide and oxygen. To ensure that the oxygen is not added to the weld, deoxidants such as silicon, aluminium and titanium are included in the welding wire, which is specially made for carbon dioxide MAG welding. The deoxidant combines with the released oxygen to form a sparse slag on the surface of the completed weld. A gas heater with an electrically heated element is used to prevent freezing of the gas regulator after prolonged use with carbon dioxide gas. Since the development of the carbon dioxide process it has become widely used for the welding of plain carbon steels.
Exploitation of radiating gas in improving solar gas heater performance
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Seyyed Abdolreza Gandjalikhan Nassab, Yahya Sheikhnejad
The result of the present numerical simulation was validated first with the numerical findings of Frouzan Nia et al. in 2020 (Foruzan Nia, Gandjalikhan Nassab, and Ansari 2020) and then with experiment (Chabane, Moummi, and Brima 2018) in Figure 3. In Ref. (Foruzan Nia, Gandjalikhan Nassab, and Ansari 2020), the laminar-forced convection of gas in a single-pass solar gas heater with a simple geometry was solved by finite volume methods. Also, working-gas was considered as a participating medium, which consequently radiative transfer equation coupled with the rest of governing equations, has to be solved. Their exact geometry considering all corresponding boundary conditions is reproduced in COMSOL Multiphysics and solved by the finite element method with a triangular unstructured mesh. The temperature profiles across the channel at two different locations, namely, and , are computed and plotted in Figure 3(a).
A life-cycle approach for multi-objective optimisation in building design: methodology and application to a case study
Published in Civil Engineering and Environmental Systems, 2018
Emanuele Bonamente, Cristina Brunelli, Francesco Castellani, Alberto Garinei, Lorenzo Biondi, Marcello Marconi, Emanuele Piccioni
The building used as a case study is a fire station located in the province of Cuneo, in northern Italy. The monitoring period for electricity and natural gas consumption is 2013–2015. The site is classified as climatic zone E by national regulations (DPR 1993), corresponding to 2735 degree days and the heating period starts October 15th and ends April 15th for a total of 182 heating days. The complex was built in 1985 and it consists of two main bodies, as shown in Figure 2. The single-storey body serves as garage, the two-storey body hosts the operative centre, the canteen, and the dorms. The gross floor area is 873 m2, the heated volume (4274 m3) is served by a single unit, a conventional natural gas heater with a nominal power of 256 kW. Space heating is performed through cast-iron radiators and wall heaters. Hot water is produced by the same unit. The building envelope is made of empty-case walls with no additional insulation. Windows have aluminium frames with no thermal cut and double glazing.
Characteristics of PM and PAHs emitted from a coal-fired boiler and the efficiencies of its air pollution control devices
Published in Journal of the Air & Waste Management Association, 2022
Tang-Wei Chen, Jyh-Cherng Chen, Zhen-Shu Liu, Kai-Hsien Chi, Moo Been Chang
In this study, a coal-fired boiler located in central Taiwan was selected for flue gas sampling to evaluate the removal efficiencies of FPM, FPM2.5, CPM, PAHs, SOx and NOx achieved with existing air pollution control devices (APCDs). Figure 1 shows the process of APCDs adopted in this coal-fired boiler. Australian coal was applied as the fuel and the proximate analysis data indicated that volatile matter, ash, fixed carbon, sulfur content and lower heating value (LHV) were 34.0%, 15.7%, 47.8%, 0.71%, and 6,726 kcal/kg, respectively. The APCDs adopted include selective catalytic reduction (SCR), electrostatic precipitator (ESP), wet flue gas desulfurization (WFGD), and wet electrostatic precipitator (WESP). After removing NOx with SCR, the flue gas passes through the medium gas–gas heater (MGGH) to recover the heat and to reduce the temperature of flue gas entering the electrostatic precipitator (ESP) to improve the removal efficiency of PM. After passing through ESP, the flue gas is introduced into the WFGD for removing SOx. The last device is WESP for the final capture of particulate matter, and then the temperature of the flue gas is raised by MGGH to prevent white plume. The flue gas sampling points include SCR inlet, SCR outlet, WESP inlet and stack. The concentrations of gaseous pollutants including NOx and SOx are measured at the SCR inlet and outlet, WESP inlet and stack, while FPM samplings are conducted at the SCR outlet, WESP inlet and stack simultaneously. PAHs samplings are carried out at the WESP inlet and stack. Additionally, FPM2.5 and CPM measurements are conducted simultaneously at the stack. The concentrations of pollutant reported are all corrected with an oxygen content of 6%.