Element and PAH constituents in the residues and liquid oil from biosludge pyrolysis in an electrical thermal furnace

Chiang, Hung‐Lung; Lin, Kun-You; Lai, Nina; Shieh, Zhu-Xin

doi:10.1016/j.scitotenv.2014.02.083

Cited by 26 publications

(21 citation statements)

References 34 publications

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“…There are two main pathways by which PAHs are known to form: at lower conversion temperatures Diels-Alder reactions take place which involve dehydrogenation, polymerization, cyclization and aromatization of hydrocarbons to form PAHs [6][7][8]. At temperatures above 400-500°C, the alternative is a pyrosynthetic pathway consisting of demethylation, demethoxylation and dehydroxylation of lignin, cellulose and hemicellulose to form phenol, alkyl-phenols and BTEX.…”

Section: Introductionmentioning

confidence: 99%

“…At temperatures above 400-500°C, the alternative is a pyrosynthetic pathway consisting of demethylation, demethoxylation and dehydroxylation of lignin, cellulose and hemicellulose to form phenol, alkyl-phenols and BTEX. This is followed by deoxygenation / dehydrogenation, connecting single compounds and condensing these into larger compounds which end up as polyaromatic networks (PAHs or pyrolytic carbon) [6,7,9,10].…”

Section: Introductionmentioning

confidence: 99%

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Strategies for producing biochars with minimum PAH contamination

Buss¹,

Graham²,

MacKinnon

et al. 2016

Journal of Analytical and Applied Pyrolysis

108

101

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With the aim to develop initial recommendations for production of biochars with minimal contamination with polycyclic aromatic hydrocarbons (PAHs), we analysed a systematic set of 46 biochars produced under highly controlled pyrolysis conditions. The effects of the highest treatment temperature (HTT), residence time, carrier gas flow and typical feedstocks (wheat / oilseed rape straw pellets (WSP), softwood pellets (SWP)) on 16 US EPA PAH concentration in biochar were investigated. Overall, the PAH concentrations ranged between 1.2 and 100 mg kg -1 . On average, straw-derived biochar contained 5.8 times higher PAH concentrations than softwood-derived biochar. In a batch pyrolysis reactor, increasing carrier gas flow significantly decreased PAH concentrations in biochar; in case of straw, the concentrations dropped from 43.1 mg kg -1 in the absence of carrier gas to 3.5 mg kg -1 with a carrier gas flow of 0.67 L min -1 ; for woody biomass PAHs concentrations declined from 7.4 mg kg -1 to 1.5 mg kg -1 with the same change of carrier gas flow. In the temperature range of 350-650°C the HTT did not have any significant effect on PAH content in biochars, irrespective of feedstock type, however, in biochars produced at 750°C the PAH concentrations were significantly higher. After detailed investigation it was deduced that this intensification in PAH contamination at high temperatures was most likely down to the specifics of the unit design of the continuous pyrolysis reactor used. Overall, it was concluded that besides PAH formation, vaporisation is determining the PAH concentration in biochar. The fact that both of these mechanisms intensify with pyrolysis temperature (one increasing and the other one decreasing the PAH concentration in biochar) could explain why no consistent trend in PAH content in biochar with temperature has been found in the literature. AbbreviationsHTT, highest treatment temperature; I.D., inner diameter

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Strategies for producing biochars with minimum PAH contamination

Buss¹,

Graham²,

MacKinnon

et al. 2016

Journal of Analytical and Applied Pyrolysis

108

101

View full text Add to dashboard Cite

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“…High cost, surfactant should be toxic, alternate process required to remove surfactant and economically costly [130] Freeze/thaw No Short treatment process and suitable for cold regions Less effective and coastally process [131] Microwave irradiation Yes Very fast and efficient and no need for chemical addition Specially designed equipment, heavy costly and not effective for large scale process [132] Electrokinetics No No need for chemical addition and fast process Process is not easy and less effective [133] Pyrolysis No Large treatment capacity, fast and effective High capital, maintenance and operating cost [134] [136] Land farming No Low cost and do not need much maintenance and applicable to large quantity Sand pollution and underground water pollution [137] Landfill No Less cost and large treatment capacity Very slow process and required more place [138] Biopile/compositing No Large treatment capacity, low cost, faster and less area required for the process Applicable in cold condition [139] Bioslurry No Fastest degradation approach, great PHC removal High cost and applicable to small scale [140]…”

Section: Solvent Extraction Nomentioning

confidence: 99%

Petroleum Hydrocarbon Removal from Wastewaters: A Review

et al. 2020

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Oil pollutants, due to their toxicity, mutagenicity, and carcinogenicity, are considered a serious threat to human health and the environment. Petroleum hydrocarbons compounds, for instance, benzene, toluene, ethylbenzene, xylene, are among the natural compounds of crude oil and petrol and are often found in surface and underground water as a result of industrial activities, especially the handling of petrochemicals, reservoir leakage or inappropriate waste disposal processes. Methods based on the conventional wastewater treatment processes are not able to effectively eliminate oil compounds, and the high concentrations of these pollutants, as well as active sludge, may affect the activities and normal efficiency of the refinery. The methods of removal should not involve the production of harmful secondary pollutants in addition to wastewater at the level allowed for discharge into the environment. The output of sewage filtration by coagulation and dissolved air flotation (DAF) flocculation can be transferred to a biological reactor for further purification. Advanced coagulation methods such as electrocoagulation and flocculation are more advanced than conventional physical and chemical methods, but the major disadvantages are the production of large quantities of dangerous sludge that is unrecoverable and often repelled. Physical separation methods can be used to isolate large quantities of petroleum compounds, and, in some cases, these compounds can be recycled with a number of processes. The great disadvantage of these methods is the high demand for energy and the high number of blockages and clogging of a number of tools and equipment used in this process. Third-party refinement can further meet the objective of water reuse using methods such as nano-filtration, reverse osmosis, and advanced oxidation. Adsorption is an emergency technology that can be applied using minerals and excellent materials using low-cost materials and adsorbents. By combining the adsorption process with one of the advanced methods, in addition to lower sludge production, the process cost can also be reduced.

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“…Most heavy metals like Pb, Cr, Ni, Cu, Zn, and Cd in SS were retained in liquefaction residues (bio-char) (Yuan et al 2011a;Leng et al 2014). Likewise, heavy metals with high boiling points (Kistler et al 1987;Trinh et al 2013) and alkaline metals (Chiang et al 2014) were mostly retained in the bio-char after pyrolysis. However, heavy metals with low boiling points like As, Hg, Cd, and Se significantly released during pyrolysis at temperature above 550°C, while other kinds of metals released with varying lower extents (Kistler et al 1987;Trinh et al 2013).…”

Section: Responsible Editor: Angeles Blancomentioning

confidence: 99%

“…However, heavy metals with low boiling points like As, Hg, Cd, and Se significantly released during pyrolysis at temperature above 550°C, while other kinds of metals released with varying lower extents (Kistler et al 1987;Trinh et al 2013). The released part of the metals would distribute in the bio-oil (Chiang et al 2014;Leng et al 2014) and possibly, the gas product (gas product only possible for high-temperature pyrolysis). These metals in bio-oil may pose potential environmental risk (Yuan et al 2015).…”

Section: Responsible Editor: Angeles Blancomentioning

confidence: 99%

Distribution behavior and risk assessment of metals in bio-oils produced by liquefaction/pyrolysis of sewage sludge

Leng

Huang

Peng

et al. 2015

Environ Sci Pollut Res

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The distribution behaviors of metals in bio-oils derived from sewage sludge (SS) by liquefaction with different solvents (ethanol, methanol, or acetone) and by pyrolysis at different temperatures (550-850 °C) were investigated. The concentrations of crust metals (K, Na, Ca, Mg, Fe, and Al) in bio-oils were much higher than those of the anthropogenic metals (Cu, Zn, Pb, Cd, Cr, Ni, V, Mn, Ba, Co, Ti, Sn, As, and Hg), but the anthropogenic metals were more inclined to distribute in bio-oil phase compared with crust metals. The anthropogenic metals in bio-oils can be divided in three groups in terms of the distribution similarities according to Cluster analysis: (A) Cu, Co, Ni, V, and Sn; (B) Cr, Ti, Mn, and Ba; (C) Pb, Cd, As, Hg, and Zn. Cu, Cr, Hg, Cd, V, Co, and Sn distributed in the liquefaction/pyrolysis bio-oils accounted for as high as 5-20% of the metals in SS and were evaluated "moderate enrichment" by the enrichment factors method. According to the potential ecological risk index (PERI) method, Hg presented very high risk, Cu presented moderate risk, and Cd presented low to moderate risk; and the overall risk levels of these bio-oils were very high risk (except P550, presented considerable risk).

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Element and PAH constituents in the residues and liquid oil from biosludge pyrolysis in an electrical thermal furnace

Cited by 26 publications

References 34 publications

Strategies for producing biochars with minimum PAH contamination

Strategies for producing biochars with minimum PAH contamination

Petroleum Hydrocarbon Removal from Wastewaters: A Review

Distribution behavior and risk assessment of metals in bio-oils produced by liquefaction/pyrolysis of sewage sludge

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