Nitrogen-Bearing Emissions From Burning Corn Straw in a Fixed-Bed Reactor: Effects of Fuel Moisture, Torrefaction, and Air Flowrate

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Emad Rokni ◽  
Yu Liu ◽  
Xiaohan Ren ◽  
Yiannis A. Levendis
Keyword(s):  
Moisture Content ◽  
Hydrogen Cyanide ◽  
Fossil Fuels ◽  
Environmental Pollutants ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Fuel Moisture ◽  
Corn Straw ◽  
Renewable Biomass ◽  
Torrefied Biomass

Combustion-generated emissions of acid gases, such as nitrogen-bearing species, constitute environmental pollutants and some are subjected to environmental regulations. Assessment of such emissions is important to decide what systems need to be put in place for their control. This applies to both conventional fossil fuels and for alternative environmentally friendlier fuels, such as renewable biomass. This research investigated the emissions of nitrogen-bearing gases, which evolve from combustion of biomass (corn straw) in a fixed bed furnace, as a function of specific air flowrate (m˙air) through the bed and of moisture content of the fuel. The effect of torrefaction of corn straw on the combustion-generated nitrogen bearing emissions was also examined. The predominant nitrogen-bearing species in the combustion effluents were hydrogen cyanide (HCN), nitrogen oxide (NO), and ammonia (NH3). Increasing m˙air through the bed, to enhance the combustion rate, increased the emissions of HCN, NO, and NH3. As the m˙air through the bed increased by a factor of 5, the amounts of HCN, NO, and NH3 gases increased by factors of 3–4. As the moisture content of the biomass was reduced by drying, the combustion-generated emissions of NO increased mildly, whereas those of both NH3 and HCN decreased. Furthermore, the combustion-generated emissions of NO and NH3 from torrefied biomass were found to be higher than those from raw biomass. In contrast, the combustion-generated emissions of HCN from torrefied biomass were found to be lower than those generated from raw biomass.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

Effect of the Moisture Content in Coal on the Pyrolysis Behavior in an Indirectly Heated Fixed-Bed Reactor with Internals

2017 ◽  
Vol 31 (2) ◽  
pp. 1347-1354 ◽  
Author(s):  
Erfeng Hu ◽  
Xi Zeng ◽  
Dachao Ma ◽  
Fang Wang ◽  
Xiaojian Yi ◽  
...  
Keyword(s):  
Moisture Content ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Pyrolysis Behavior

Effect of air preheating and fuel moisture on combustion characteristics of corn straw in a fixed bed

2008 ◽  
Vol 49 (12) ◽  
pp. 3560-3565 ◽  
Author(s):  
Wei Zhao ◽  
Zhengqi Li ◽  
Guangbo Zhao ◽  
Fangshi Zhang ◽  
Qunyi Zhu
Keyword(s):  
Fixed Bed ◽  
Combustion Characteristics ◽  
Fuel Moisture ◽  
Corn Straw

Hydrogen Chloride Release From Combustion of Corn Straw in a Fixed Bed

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Xiaohan Ren ◽  
Xiaoxiao Meng ◽  
Aidin Panahi ◽  
Emad Rokni ◽  
Rui Sun ◽  
...  
Keyword(s):  
Hydrogen Chloride ◽  
Flow Rate ◽  
Air Flow ◽  
Fixed Bed ◽  
Air Flow Rate ◽  
Corn Straw ◽  
Release Rates ◽  
Torrefied Biomass ◽  
Hcl Gas ◽  
Biomass Ashes

Chlorine plays an important role in the slagging and corrosion of boilers that burn high-chlorine content biomass. This research investigated the emissions of hydrogen chloride (HCl) gas from combustion of biomass in a fixed bed, as functions of the mass air flow rate through the bed and of the moisture content of the fuel. The biomass burned was corn straw, either raw or torrefied. Results showed that increasing the air flow rate through the bed increased the release of HCl gas, as a result of enhanced combustion intensity and associated enhanced heat release rates. When the airflow through the bed was increased by a factor of six, the amount of fuel-bound chlorine converted to HCl nearly tripled. Upon completion of combustion, most of the chlorine remained in the biomass ashes, with the exception of the highest air flow case where the fraction of chlorine released in HCl equaled that captured in the ashes. HCl emissions from torrefied biomass were found to be lower than those from raw biomass. Finally, drying the biomass proved to be beneficial in drastically curtailing the generation of HCl gas.

scholarly journals Steam Reforming of Model Bio-Oil Aqueous Fraction Using Ni-(Cu, Co, Cr)/SBA-15 Catalysts

2019 ◽  
Vol 20 (3) ◽  
pp. 512 ◽  
Author(s):  
José A. Calles ◽  
Alicia Carrero ◽  
Arturo J. Vizcaíno ◽  
Lourdes García-Moreno ◽  
Pedro J. Megía
Keyword(s):  
Steam Reforming ◽  
Fossil Fuels ◽  
Carbon Number ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Coke Deposition ◽  
Aqueous Fraction ◽  
Promising Alternative ◽  
Bio Oil ◽  
Carbon Filaments

Hydrogen obtained from biomass derivatives is considered a promising alternative to fossil fuels. The aim of this work is to test the viability of Ni-M/SBA-15 (M: Co, Cu, Cr) catalysts for the hydrogen production from bio-oil aqueous fraction reforming. Tests were performed in a fixed-bed reactor at 600 °C and atmospheric pressure. Firstly, the steam reforming (SR) of acetic acid, hydroxyacetone, furfural and phenol, as representative constituents of the bio-oil aqueous fraction, was carried out. Lower reactivity with increasing carbon number and decreasing steam-to-carbon ratio was observed. Coking rate during SR is a consequence of carbon number and aromaticity of the reactant, as well as the steam-to-carbon ratio. However, deactivation also depends on the graphitization degree of carbon filaments, higher in the case of coke formed from phenol. Then, the performance of the Ni-M/SBA-15 catalysts was studied in the reforming of a bio-oil aqueous fraction surrogate containing the four model compounds. Ni-Co/SBA-15 and Ni-Cr/SBA-15 samples were the most active because Co also catalyze the steam reforming reactions and Cr promotes the formation of very small Ni crystallites accounting for high conversion and the low coke deposition (~8 times lower than Ni/SBA-15) in the form of poorly condensed carbon filaments.

scholarly journals The Grindability of Biochars from Agroforestry Biomass Prepared under Different Torrefied Conditions

2019 ◽  
Vol 118 ◽  
pp. 01051
Author(s):  
Hewei Jiang ◽  
Yangtian Ye ◽  
Ping Lu
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Wheat Straw ◽  
Size Distribution ◽  
Mass Fraction ◽  
Fixed Bed ◽  
Holding Time ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Agricultural Biomass

The torrefaction experiments of four biomass including agricultural biomass (corn straw (CS) and wheat straw (WS)) and forestry biomass (polar wood (PW) and cedar wood (CW)) were carried out in a fixed bed reactor at torrefaction temperature of 200-300°C and holding time of 10-60min, the effects of torrefaction temperature and holding time on biochar grindability based on the component analysis and the particle size distribution of ground biomass and biochars. The obtained results indicated that the mass fraction of ground biochar with particle size less than 150 μm increases with increasing torrefaction temperature, and the mass fraction of ground biochar with particle size less than 150 μm achieves 100%. The larger the λC, the better the grindability of biochar. The correlation between the grindability of the woody biochar and the λC is not as good as that of the straw biochar. The grindability of corn straw biochar and cedar wood biochar is improved with the increase of holding time at the same torrefaction temperature, however, the grindability of wheat straw biochar and polar wood biochar gets a little change, which can keep good grindability at higher torrefaction temperature large than 275°C.

Pyrolysis of Empty Fruit Bunch (EFB) in a Vertical Fixed Bed Reactor

2014 ◽  
Vol 695 ◽  
pp. 228-231 ◽  
Author(s):  
K. Azduwin ◽  
Mohd Jamir Mohd Ridzuan ◽  
A.R. Mohamed ◽  
S.M. Hafis
Keyword(s):  
Particle Size ◽  
Fossil Fuels ◽  
Pyrolysis Temperature ◽  
Hold Time ◽  
Maximum Yield ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Effect Of Temperature ◽  
Empty Fruit Bunch ◽  
Bio Oil

Uncontrolled uses of fossil fuels lead to serious energy problems and since Malaysia is one of the largest producers of palm oil in the world, it has caused a lot of waste such as empty fruit bunches (EFB) which can actually be converted into renewable energy via pyrolysis. In this work, firstly the characterizations of the EFB were analyzed such as elemental, proximate and component analysis. The pyrolysis experiment of empty fruit bunch using vertical fixed-bed reactor was conducted at different pyrolysis temperature range from 300 - 600 °C and the particle size of EFB was also varied from 125-250 μm with constant nitrogen flow rate of 100 cm3/min, heating rate of 30 °C/min, and 30 minutes hold time. For the effect of temperature, the optimum pyrolysis temperature was 500 °C to produce maximum yield of bio-oil which is 39.2 wt. % while 46.13 wt. % is the highest bio-oil yield produced at size of 500-710 μm for the effect of particle size. The analysis on bio-oil was conducted by using Fourier Transform Infrared (FTIR) with the results shows for the presents of phenol/alcohol group, ketones and C-O bond. The bio-oil obtained is in the acidic condition with pH 3.5.

scholarly journals PENGARUH KOMPOSISI BRIKET BIOMASSA KULIT KACANG TANAH DAN ARANG TONGKOL JAGUNG TERHADAP KARAKTERISTIK BRIKET

2015 ◽  
Vol 5 (2) ◽  
Author(s):  
Purnawarman Purnawarman ◽  
Nurchayati Nurchayati ◽  
Yesung Allo Padang
Keyword(s):  
Moisture Content ◽  
Alternative Fuels ◽  
Fossil Fuels ◽  
Agricultural Waste ◽  
Ash Content ◽  
Heating Value ◽  
Renewable Biomass ◽  
Lower Heating Value ◽  
Petroleum Reserves ◽  
Lower Heating

Energy crisis in the world especially from fossil fuels which caused by the depletion of non-renewable petroleum reserves. It is therefore necessary to find sources of alternative fuels that are renewable. Biomass is a solid waste that can be used as a fuels source. Peanuts shell and cobs are biomass from agricultural waste which is quite abundant so it is potential to be used as a source of alternative fuels.In this study, peanuts shell biomass combined with charcoal cobs to be made into briquettes by varying the percentage composition of peanuts shell biomass and charcoal cobs as follows 75 : 25, 50 : 50, and 25 : 75. Briquettes that have been printed and then tested its characteristic include heating value, moisture content and ash content.The results show that as the increasing percentage of the charcoal cobs  have a significant influence on the characteristic of the briquettes. Briquettes with mix KKT 25 : ATJ 75 has an higher heating value (HHV) and lower heating value (LHV) the highest is equal to 28.718 kJ/kg and 28.279 kJ/kg, and the lowest percentage of moisture content is equal to 5.854%, but the highest result percentage of ash content is equal to 9.326%. Based on the test of these characteristic, biomass briquettes peanuts shell - charcoal cobs meet quality standards that have been established and eligible to became a source of alternative fuels.

scholarly journals Properties of chars obtained with pyrolysis of Castanea sativa by product

2017 ◽  
Vol 21 (2) ◽  
pp. 1083-1092 ◽  
Author(s):  
Eylem Pehlivan
Keyword(s):  
Carbon Content ◽  
Surface Area ◽  
Fossil Fuels ◽  
Fixed Bed ◽  
Castanea Sativa ◽  
Fixed Bed Reactor ◽  
Heating Rates ◽  
X Ray ◽  
High Heating Value ◽  
Magnetic Resonance Scanning

The application of biomass derived energy is gaining importance due to the decreasing supply of fossil fuels and growing environmental concerns. This study described the possibility of utilizing Castanea sativa?s by-product as biofuels by producing char via pyrolysis. The process was carried out in a fixed-bed reactor at different heating rates of 10?C, 100?C, and 200?C per minute at temperatures ranging from 400?C to 700?C, and a nitrogen flow rate of 100 cm3 per minute. The produced chars were characterized by proximate and elemental analyses, Brunauer-Emmett-Teller surface area, nuclear magnetic resonance, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray fluorescence analyses. The char yield was found to decrease as both pyrolysis temperature and heating rate increases. The carbon content of char ranged from 68 to 87 wt.%, which correspond to approximately 43% of carbon in the biomass. The char obtained at 700?C had high fixed carbon content (79.90%) as well as high heating value, and hence, it could be used as a solid fuel or as a precursor in the activated carbon production with its 268 m2 per gram surface area.

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