57Fe Mössbauer spectroscopic studies of fly ash from coal-fired power plants and bottom ash from lignite-natural gas combustion

Abstract. Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO2 mole fractions and Δ14C and δ13C values of CO2 in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO2 contributions from fossil fuel combustion (Cff) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena Cff during the Great Recession of 2008–2010, which is consistent with the bottom-up inventory determined by the California Air Resources Board. The isotopic variations and total atmospheric CO2 from our observations are used to infer seasonality of natural gas and petroleum combustion. The trend of CO2 contributions to the atmosphere from natural gas combustion is out of phase with the seasonal cycle of total natural gas combustion seasonal patterns in bottom-up inventories but is consistent with the seasonality of natural gas usage by the area's electricity generating power plants. For petroleum, the inferred seasonality of CO2 contributions from burning petroleum is delayed by several months relative to usage indicated by statewide gasoline taxes. Using the high-resolution Hestia-LA data product to compare Cff from parts of the basin sampled by winds at different times of year, we find that variations in observed fossil fuel CO2 reflect seasonal variations in wind direction. The seasonality of the local CO2 excess from fossil fuel combustion along the coast, on Palos Verdes peninsula, is higher in autumn and winter than spring and summer, almost completely out of phase with that from Pasadena, also because of the annual variations of winds in the region. Variations in fossil fuel CO2 signals are consistent with sampling the bottom-up Hestia-LA fossil CO2 emissions product for sub-city source regions in the LA megacity domain when wind directions are considered.

Download Full-text

Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

Volume 4A: Combustion, Fuels, and Emissions ◽

10.1115/gt2018-75701 ◽

2018 ◽

Author(s):

Max H. Baumgärtner ◽

Thomas Sattelmayer

Keyword(s):

Natural Gas ◽

Mass Flow ◽

Power Output ◽

Gas Turbines ◽

Power Plants ◽

Combined Cycle ◽

Nox Emissions ◽

Gas Combustion ◽

Low Load ◽

Natural Gas Combustion

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics which lead to CO and unburned hydrocarbon (UHC) emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass-flow and the power output can be reduced. An Autothermal On-board Syngas Generator in combination with two different burner concepts for natural gas/syngas mixtures was presented in a previous study [1]. The study at hand shows a mass-flow variation of the reforming process with mass-flows which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and non-swirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by natural gas combustion of the swirl pilot was reported in last year’s paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170 K – 210 K lower for the syngas compared to low load pure natural gas combustion. This corresponds to a decrease of 15–20 % in terms of thermal power.

Download Full-text

Research of pressure influence in the gas supply system on the energy consuption level of gas devices

JOURNAL OF HYDROCARBON POWER ENGINEERING ◽

10.31471/2311-1399-2019-2(12)-56-63 ◽

2019 ◽

Vol 6 (2) ◽

pp. 56-63

Author(s):

L. D. Pylypiv ◽

І. І. Maslanych

Keyword(s):

Natural Gas ◽

Residential Buildings ◽

Supply System ◽

Normal Operation ◽

Gas Combustion ◽

Efficient Operation ◽

Gas Consumption ◽

Natural Gas Combustion ◽

Gas Supply

There are investigated the influence of operating pressures in the gas supply system on the level of such energy indicators as efficiency, gas flow and gas overrun by gas equipment in residential buildings. There is established a relationship between the values of operating pressures in the gas supply system and the gas consumption level of household appliances. The causes of insufficient pressure in the gas networks of settlements are analyzed in the article. There is also developed an algorithm for calculating the change in the efficiency of gas appliances depending on the operational parameters of the gas network. It has been found that the most efficient operation of gas appliances is observed at an overpressure at the inlet of gas appliances of about 1200 Pa.To ensure the required quality of natural gas combustion among consumers and minimize gas consumption there are justified the following measures in the article: coordinating a domestic regulatory framework for assessing the quality of natural gas with international norms and standards; improving the preparation of gas coming from local wells before supplying it to gas distribution networks; auditing low pressure gas pipelines and reconstructing areas affected by corrosion; ensuring standard gas pressure in the network for the normal operation of domestic gas appliances; stating quality indicators of natural gas combustion by gas sales organizations.

Download Full-text

Development of environment-friendly dual fuel pulverized coal-natural gas combustion technology for the co-firing power plant boiler: Experimental and numerical analysis

Energy ◽

10.1016/j.energy.2021.120550 ◽

2021 ◽

Vol 228 ◽

pp. 120550

Author(s):

Iman Rahimipetroudi ◽

Kashif Rashid ◽

Je Bok Yang ◽

Sang Keun Dong

Keyword(s):

Numerical Analysis ◽

Power Plant ◽

Natural Gas ◽

Dual Fuel ◽

Environment Friendly ◽

Gas Combustion ◽

Power Plant Boiler ◽

Combustion Technology ◽

Natural Gas Combustion ◽

Plant Boiler

Download Full-text

The effect of nitrogen content in oxy-natural gas combustion on the CO concentration in premixed flame

Journal of the Energy Institute ◽

10.1016/j.joei.2015.11.003 ◽

2017 ◽

Vol 90 (1) ◽

pp. 21-29 ◽

Cited By ~ 1

Author(s):

Wojciech Jerzak

Keyword(s):

Natural Gas ◽

Nitrogen Content ◽

Premixed Flame ◽

Gas Combustion ◽

Co Concentration ◽

Natural Gas Combustion

Download Full-text

Multiflame Patterns in Swirl-Driven Partially Premixed Natural Gas Combustion

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1520159 ◽

2002 ◽

Vol 125 (1) ◽

pp. 40-45 ◽

Cited By ~ 5

Author(s):

K. P. Vanoverberghe ◽

E. V. Van den Bulck ◽

M. J. Tummers ◽

W. A. Hu¨bner

Keyword(s):

Natural Gas ◽

Combustion Chamber ◽

Gas Flow ◽

State Transition ◽

Gas Combustion ◽

Bifurcation Phenomena ◽

Major Species ◽

Partially Premixed ◽

Natural Gas Combustion ◽

Low Nox Emission

Five different flame states are identified in a compact combustion chamber that is fired by a 30 kW swirl-stabilized partially premixed natural gas burner working at atmospheric pressure. These flame states include a nozzle-attached tulip shaped flame, a nonattached torroidal-ring shaped flame (SSF) suitable for very low NOx emission in a gas turbine combustor and a Coanda flame (CSF) that clings to the bottom wall of the combustion chamber. Flame state transition is generated by changing the swirl number and by premixing the combustion air with 70% of the natural gas flow. The flame state transition pathways reveal strong hysteresis and bifurcation phenomena. The paper also presents major species concentrations, temperature and velocity profiles of the lifted flame state and the Coanda flame and discusses the mechanisms of flame transition and stabilization.

Download Full-text

Characterization of Coal Fly Ash, Bottom Ash and their Possibilities as Catalysts for Biodiesel Production

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.904.413 ◽

2021 ◽

Vol 904 ◽

pp. 413-418

Author(s):

Wilasinee Kingkam ◽

Sasikarn Nuchdang ◽

Dussadee Rattanaphra

Keyword(s):

Fly Ash ◽

Palm Oil ◽

Power Plants ◽

Coal Fly Ash ◽

Bottom Ash ◽

Biodiesel Production ◽

Catalyst Loading ◽

Free Lime ◽

Operation Conditions ◽

Class C

Coal fly ash (CFA) and bottom ash (BA) obtained from coal fired power plants in Thailand and local supplier were characterized using XRF, XRD and N2 adsorption-desorption techniques. Their possibilities for conversion of palm oil into biodiesel were investigated. Selected CFA was also modified with lanthanum (La) at different La loading and the influence of La loading on biodiesel conversion was evaluated. The resulted showed that the Class C CFA as contained large amount of CaO (free lime) could catalyze the transesterification to achieve the highest FAME content of 89% under the operation conditions; the reaction temperature of 200 °C, the reaction pressure of 39 bars, the catalyst loading of 5 wt% of oil, the molar of oil to methanol of 1:30 and the stirring speed of 600 rpm for 5 h. The addition of La on the Class C CFA had a negative effect on conversion of palm oil. The FAME content decreased gradually from 89 to 62% with increasing La loading from 0 to 1 wt%.

Download Full-text