Low-nitrogen oxides combustion of dried sludge using a pilot-scale cyclone combustor with recirculation

In this study, the feasibility of the carburization of vanadium-bearing hot metal was first investigated by thermodynamic analysis. Next, three carburizers, namely a low-nitrogen carburizer, anthracite, and coke, were used for carburization of 500 g of vanadium-bearing hot metal at 1450 °C, 1500 °C, and 1550 °C, respectively. The carbon increments for the low-nitrogen carburizer, anthracite and coke followed decreasing order in the temperature range from 1450 °C to 1550 °C. Anthracite was the most cost-effective carburizer. Hence, anthracite is used in pilot-scale experiments of the vanadium-bearing hot metal (100 kg and 200 kg). Finally, vanadium extraction experiments of the vanadium-bearing hot metal were carried out in a top-bottom-combined blowing induction furnace. It is proved that the average superheat degree of semi-steel increases from 100 °C to 198 °C by the carburization of vanadium-containing hot metal.

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Modeling of a dry low nitrogen oxides burner using a three-dimensional computational fluid dynamics simulation

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/09544089211035595 ◽

2021 ◽

pp. 095440892110355

Author(s):

Guodong Sun ◽

Xuejing Duan ◽

Bo Hao ◽

Afshin Davarpanah

Keyword(s):

Nitrogen Oxides ◽

Greenhouse Gases ◽

Power Plants ◽

Three Dimensional ◽

Control Policy ◽

Dynamics Simulation ◽

Weather Patterns ◽

United Nations General ◽

Fluent Software ◽

Low Nitrogen

Nitrogen oxides are considered as one of the greenhouse gases. Among the most significant emission sources for this gas is a natural gas-fired power plant. The United Nations General assembly suggested in 1988 that human activities can negatively impact weather patterns, and thus they should be controlled. This control policy can improve the efficiency of final consumers such as power plants, cars, or other energy-intensive industries. In this paper, the existing strategies and explicitly making the dry low nitrogen oxides burner reduce greenhouse gases in power plants are explored. The geometry of the burner has been produced in a three-dimensional form in GAMBIT software, and the results of the simulation have been expressed through FLUENT software. Contours of pressure, temperature, and velocity of the fluid in the furnace are also derived. It is concluded that the dry low nitrogen oxides burners plan has a better result compared with other strategies.

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Multi-point micro-flame ignited hybrid lean-burn combustion of gasoline with direct injection dimethyl ether

International Journal of Engine Research ◽

10.1177/1468087419840469 ◽

2019 ◽

Vol 22 (1) ◽

pp. 140-151 ◽

Cited By ~ 2

Author(s):

Xue-Qing Fu ◽

Bang-Quan He ◽

Si-Peng Xu ◽

Tao Chen ◽

Hua Zhao ◽

...

Keyword(s):

Nitrogen Oxides ◽

Heat Release ◽

Dimethyl Ether ◽

Direct Injection ◽

Injection Timing ◽

Ignition Timing ◽

Double Peak ◽

Lean Burn ◽

Combustion Duration ◽

Low Nitrogen

Lean-burn combustion is effective in reducing fuel consumption of gasoline engines because of the higher specific heat ratio of the fuel lean mixture and reduced heat loss from lower combustion temperature. However, its application to real engines is hampered by the unstable ignition, high cyclic variability, and partial-burn due to slower combustion, as well as the restricted maximum lean-burn air/fuel ratio limit and the insufficiently low nitrogen oxides emission. Multi-point micro-flame-ignited hybrid combustion has been proposed and applied to extend the lean burn limit of premixed gasoline and air mixture. To achieve micro-flame-ignited combustion in premixed lean gasoline mixture formed by port fuel injection, a small amount of dimethyl ether is injected directly into the cylinder of a four-stroke gasoline engine to control and accelerate the ignition and combustion process so that the engine could be operated with the overall excess air coefficient (Lambda) of 1.9. The results show that heat release processes can be grouped into three forms, that is, ramp type, double-peak type, and trapezoid type. Regardless of single or split injections, direct injection timing of dimethyl ether dominates the features of heat release. The ramp type occurs at early injection timing while the double-peak type takes place at late injection timing. Trapezoid type appears between the above two types. Dimethyl ether injection timing controls the ignition timing and has less effect on combustion duration. Single injection of dimethyl ether leads to much earlier ignition timing and slightly longer combustion duration, forming higher nitrogen oxides emissions than the split injections. Ultra-low nitrogen oxides emissions and higher thermal efficiency are achieved in the ramp type combustion compared to the other two types of combustion in both injection approaches.

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Ecological stabilization of thickened wastewater sludge from CAST process

Water Science & Technology ◽

10.2166/wst.2008.745 ◽

2008 ◽

Vol 58 (10) ◽

pp. 1911-1916 ◽

Cited By ~ 1

Author(s):

Y. B. Cui ◽

X. H. Wu ◽

Zh. Sh. Liu ◽

J. Zh. Liu ◽

Y. Z. Lin

Keyword(s):

Protein Content ◽

Operation Time ◽

Pilot Scale ◽

Quadratic Equation ◽

Wastewater Sludge ◽

Thickness Variation ◽

Significant Difference ◽

Treatment And Disposal ◽

Dried Sludge ◽

Relationship Of

Wastewater sludge ecological stabilization (WWSES) pilot scale experiments were conducted for thickening treatment and disposal of sludge which came from Cyclic Activated Sludge Technology (CAST) process. The study was performed over the periods from June to November 2005 and from May to November 2006, on a bed of 80 m2. The sludge loadings were stopped for the winter from December 2005 and resumed in May 2006. The results shows that dried sludge layer has higher permeation coefficients of 0.15–1.3 m/h. It is suggested that the percolate did not filtrate downwards evenly, part of percolate filtrates downwards along stems, roots and cracks existing in dried sludge which have lower flow resistance. The relationship of dried sludge thickness and operation time is in accord with quadratic equation under fluctuating sludge loadings. Linear regression equation can indicate dried sludge thickness variation under fixed sludge loading. In comparison with natural ones, coarse protein content of Phragmites australis roots in the system is twice as high, coarse fiber content of roots, coarse fat content of stems and leaf are obviously higher; and coarse protein content of Typha augustifolia in the system are obviously higher, while coarse fat and coarse fiber contents have no significant difference.

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Reduction of nitrogen oxides by injection of urea in the freeboard of a pilot scale fluidized bed combustor

Fuel ◽

10.1016/0016-2361(89)90295-0 ◽

1989 ◽

Vol 68 (12) ◽

pp. 1565-1569 ◽

Cited By ~ 7

Author(s):

Koen E. Knol ◽

Eduard A. Bramer ◽

Marinus Valk

Keyword(s):

Nitrogen Oxides ◽

Fluidized Bed ◽

Pilot Scale ◽

Fluidized Bed Combustor

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Reduction in nitrogen oxides emissions by MILD combustion of dried sludge

Renewable Energy ◽

10.1016/j.renene.2013.07.005 ◽

2014 ◽

Vol 65 ◽

pp. 29-35 ◽

Cited By ~ 10

Author(s):

Sung Hoon Shim ◽

Sang Hyun Jeong ◽

Sang-Sup Lee

Keyword(s):

Nitrogen Oxides ◽

Mild Combustion ◽

Dried Sludge

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Characterization of Microbial Communities Removing Nitrogen Oxides from Flue Gas: the BioDeNOx Process

Applied and Environmental Microbiology ◽

10.1128/aem.71.10.6345-6352.2005 ◽

2005 ◽

Vol 71 (10) ◽

pp. 6345-6352 ◽

Cited By ~ 30

Author(s):

Rajkumari Kumaraswamy ◽

Udo van Dongen ◽

J. Gijs Kuenen ◽

Wiebe Abma ◽

Mark C. M. van Loosdrecht ◽

...

Keyword(s):

Nitrogen Oxides ◽

16S Rrna ◽

Microbial Communities ◽

Flue Gas ◽

Iron Reduction ◽

Denaturing Gradient Gel Electrophoresis ◽

Pilot Scale ◽

Rrna Gene ◽

16S Rrna Analysis ◽

Gradient Gel Electrophoresis

ABSTRACT BioDeNOx is an integrated physicochemical and biological process for the removal of nitrogen oxides (NOx) from flue gases. In this process, the flue gas is purged through a scrubber containing a solution of Fe(II)EDTA2−, which binds the NOx to form an Fe(II)EDTA·NO2− complex. Subsequently, this complex is reduced in the bioreactor to dinitrogen by microbial denitrification. Fe(II)EDTA2−, which is oxidized to Fe(III)EDTA− by oxygen in the flue gas, is regenerated by microbial iron reduction. In this study, the microbial communities of both lab- and pilot-scale reactors were studied using culture-dependent and -independent approaches. A pure bacterial strain, KT-1, closely affiliated by 16S rRNA analysis to the gram-positive denitrifying bacterium Bacillus azotoformans, was obtained. DNA-DNA homology of the isolate with the type strain was 89%, indicating that strain KT-1 belongs to the species B. azotoformans. Strain KT-1 reduces Fe(II)EDTA·NO2− complex to N2 using ethanol, acetate, and Fe(II)EDTA2− as electron donors. It does not reduce Fe(III)EDTA−. Denaturing gradient gel electrophoresis analysis of PCR-amplified 16S rRNA gene fragments showed the presence of bacteria closely affiliated with members of the phylum Deferribacteres, an Fe(III)-reducing group of bacteria. Fluorescent in situ hybridization with oligonucleotide probes designed for strain KT-1 and members of the phylum Deferribacteres showed that the latter were more dominant in both reactors.

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Investigation of municipal sludge gasification potential: Gasification characteristics of dried sludge in a pilot-scale downdraft fixed bed gasifier

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2019.01.014 ◽

2019 ◽

Vol 44 (32) ◽

pp. 17397-17410 ◽

Cited By ~ 11

Author(s):

Azize Ayol ◽

Ozgun Tezer Yurdakos ◽

Alim Gurgen

Keyword(s):

Fixed Bed ◽

Pilot Scale ◽

Municipal Sludge ◽

Downdraft Fixed Bed ◽

Dried Sludge

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Investigation of Adjacent Lifted Flames Interaction in an Inline and Inclined Multi-Burner Arrangement

10.1115/gt2021-59941 ◽

2021 ◽

Author(s):

Mohamed Shamma ◽

Stefan Raphael Harth ◽

Nikolaos Zarzalis ◽

Dimosthenis Trimis ◽

Sven Hoffmann ◽

...

Keyword(s):

Nitrogen Oxides ◽

Experimental Tests ◽

Ambient Conditions ◽

Stability Range ◽

Spray Flames ◽

Annular Combustor ◽

Lifted Flames ◽

Inclination Angles ◽

Swirled Flames ◽

Low Nitrogen

Abstract The main objective of this research is to assess an innovative, low nitrogen oxides emission combustor concept, which has the potential to achieve the long term European emissions goals for aircraft engines. Lean lifted spray flames and their very low nitrogen oxides emissions are combined with an inclination of burners in annular combustor leading to a more compact combustor with superior stability range. The presented combustor concept was developed in the frame of the European research project CHAIRLIFT (Compact Helical Arranged combustoRs with lean LIFTed flames). CHAIRLIFT combustor concept is based on “low swirl” lean lifted spray flames, which features a high degree of premixing and consequently significantly reduced nitrogen oxides emissions and flashback risk compared to conventional swirl stabilized flames. In the CHAIRLIFT combustor concept, the lifted flames are combined with Short Helical Combustors arrangement to attain stable combustion by tilting the axis of the flames relative to the axis of the turbine to enhance the interaction of adjacent flames in a circumferential direction. A series of experimental tests were conducted at a multi-burner array test rig consisting of up to five modular burners at different burner inclination angles (0° and 45°), equivalence ratios, and relative air pressure drop at ambient conditions. For all investigated configurations, a remarkable high lean blow out for non-piloted burners (ϕLBO = 0.29–0.37), was measured. The multi-burner configurations were observed having a superior stability range in contrast to the typical decrease in stability from single to high swirl multi-burner. The unwanted flow deflection of highly swirled flames in Short Helical Combustors arrangement, could be avoided with the investigated low swirl lifted flames. Moreover, the flame chemiluminescence (OH*) measurements were used to provide a qualitative characterization of the flame topology. Complementary numerical investigations were carried out using different numbers of burners to evaluate the effect of boundary conditions.

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