50-32-8 Hazards Identification
Signal:
Danger
GHS Hazard Statements:
H317: May cause an allergic skin reaction [Warning Sensitization, Skin]
H340: May cause genetic defects [Danger Germ cell mutagenicity]
H350: May cause cancer [Danger Carcinogenicity]
H360FD: May damage fertility; May damage the unborn child [Danger Reproductive toxicity]
H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]
H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]
Precautionary Statement Codes:
P203, P261, P272, P273, P280, P281, P302+P352, P318, P321, P333+P313, P362+P364, P391, P405, and P501
Hazard Classes and Categories:
Carc. 1B
Muta. 1B
Repr. 1B
Skin Sens. 1
Aquatic Acute 1
Aquatic Chronic 1
Skin Sens. 1 (99.88%)
Muta. 1B (99.88%)
Carc. 1B (99.88%)
Repr. 1B (98.33%)
Aquatic Acute 1 (81.36%)
Aquatic Chronic 1 (98.92%)
Carcinogenicity - category 1B
Germ cell mutagenicity - category 1B
Reproductive toxicity - category 1B
Skin sensitisation - category 1
Hazardous to the aquatic environment (chronic) - category 1
Germ cell mutagenicity - Category 1B
Carcinogenicity - Category 1A
Reproductive toxicity - Category 1B
Specific target organ toxicity - Repeated exposure - Category 2 (hematopoietic system)
Hazardous to the aquatic environment (Acute) - Category 1
Hazardous to the aquatic environment (Long-term) - Category 1
Skin corrosion/irritation - Category 2
Carcinogenicity - Category 1B
Specific target organ toxicity - Repeated exposure - Category 2 (bone marrow, respiratory system)
Carcinogens, Mutagens
Hazards Summary:
Benzo(a)pyrene is a biomarker of polycyclic aromatic hydrocarbon (PAH) exposure as occurs in aluminum production and coal gasification, two processes which are carcinogenic to humans (urinary bladder and lung). Exposure to soot in chimney sweeping is a known human carcinogen; Other occupational exposures to PAHs classified as Group 1 are coke production, coal-tar distillation, paving and roofing with coal-tar pitch. [Reference #1] Reason for exclusion from occupational carcinogens: Group 1 classification based on mechanistic upgrade. [PMID 29769352] See POLYCYCLIC AROMATIC HYDROCARBONS. See Soots, Coal tar pitch volatiles, Coke oven emissions, and Shale oils.
50-32-8 Usage
Uses
1. Used in Toxicological and Cancer Research:
Benzo[a]pyrene is extensively used in cancer research and for gas chromatography (GC) and liquid chromatography (LC) analysis. It serves as a multipurpose intermediate and a positive control in carcinogenicity studies due to its well-known carcinogenic properties.
2. Used in Rubber/Plastic Production:
Benzo[a]pyrene containing extender oil is utilized in the rubber and plastic industry to achieve the desired elasticity at a more affordable price.
3. Used in Paints and Coatings:
Benzo[a]pyrene containing coal tar pitch is employed in various paints or coatings as corrosion protection coats for hydraulic equipment, pipework, steel pilings in ports, vessels, and sealcoat products.
4. Used as Wood-Preservatives:
Benzo[a]pyrene can be used as a wood-preservative to prevent wood parasites and to protect wood from drying out.
References
https://monographs.iarc.fr/ENG/Monographs/vol100F/mono100F-14.pdf
http://www.dhss.delaware.gov/dph/files/benzopyrenefaq.pdf
https://greenliving.epa.gov.tw
https://www.umweltbundesamt.de
Barbara J. Mahler, Peter C. Van Metre, Judy L. Crane, Alison W. Watts, ?Mateo Scoggins, and E. Spencer Williams, Coal-Tar-Based Pavement Sealcoat and PAHs: Implications for the Environment, Human Health, and Stormwater Management, Environ Sci Technol, 2012, vol. 46, 3039-3045
Air & Water Reactions
Insoluble in water.
Reactivity Profile
BENZO[A]PYRENE undergoes photo-oxidation after irradiation in indoor sunlight or by fluorescent light in organic solvents. Incompatible with strong oxidizing agents including various electrophiles, peroxides, nitrogen oxides and sulfur oxides. Oxidized by ozone, chromic acid and chlorinating agents. Readily undergoes nitration and halogenation. Hydrogenation occurs with platinum oxide .
Hazard
Highly toxic, confirmed carcinogen by inhalation.
Health Hazard
The acute oral toxicity of benzo[a]pyrene islow. This may be due to the poor absorption of Benzo[a]pyrene by the gastrointestinal tract.The lethal dose in mice from intraperitonealadministration is reported as 500 mg/kg(NIOSH 1986).Animal studies show sufficient evidence ofits carcinogenicity by all routes of exposureaffecting a variety of tissues, which includethe lungs, skin, liver, kidney, and blood.Dasenbrock et al. (1996) have investigatedthe carcinogenic potency of carbon particles,diesel soot and benzo[a]pyrene in rats fromrepeated intracheal administration in a 16-week study. A total dose of 15 mg purebenzo[a]pyrene caused lung tumor in theexperimental animals at a rate similar tothat caused by diesel soot and carbon blackparticles.Lodovici et al. (1998) measured the levelsof PAHs and benzo[a]pyrenediol epoxideDNA adduct in autoptic lung samples ofsmokers and non-smokers. Benzo[a]pyrenediol epoxide resulting from metabolic activation of benzo[a]pyrene binds to DNA to forman adduct, the levels of which can be used as abiomarker to evaluate the exposure of humansto benzo(a)pyrene.Benz[a]pyrene exhibited teratogeniceffects in test species. It is a mutagen.It showed positive in a histidine rever-sion–Ames test, cell transform mouse embryotest, and in in vitro sister chromatid exchange(SCE)–human lymphocytes..
Fire Hazard
Literature sources indicate that BENZO[A]PYRENE is nonflammable.
Toxicology
benzo[a]pyrene (BP) is a reasonably potent contact carcinogen, and therefore has been subjected
to extensive carcinogenic testing. A diet containing 25 ppm of benzo[a]pyrene (BP) fed to
mice for 140 days produced leukemia and lung adenomas in addition to
stomach tumors. Skin tumors developed in over 60% of the rats treated topically
with approximately 10 mg of benzo[a]pyrene three times per week.
The incidence of skin tumors dropped to about 20% when treatment was
about 3 mg 3 per week. Above the 10 mg range, however, the incidence
of skin tumors increased dramatically to nearly 100%.
benzo[a]pyrene (BP) is also carcinogenic when administered orally. In one experiment,
weekly doses of greater than 10 mg administered for 10 weeks induced
stomach cancers, although no stomach cancers were produced at the dose
of 10 mg or less. At 100 mg doses, nearly 79% of the animals had developed
stomach tumors by the completion of the experiment.
When 15 ppm of benzo[a]pyrene (BP) in feed was orally administered to mice, production of
leukemia, lung adenomas, and stomach tumors were observed after 140 days.
Safety Profile
Confirmed carcinogen withexperimental carcinogenic, neoplastigenic, andtumorigenic data. A poison via subcutaneous,intraperitoneal, and intrarenal routes. Experimentalteratogenic and reproductive effects. Human mutation data reported. A skin irritant.
Potential Exposure
Benzopyrene (BP) is a PAH that
has no commercial-scale production. B(a)P is produced in
the United States by one chemical company and distributed
by several specialty chemical companies in quantities from
100 mg to 5 g for research purposes. Although not manufactured
in great quantity, B(a)P is a by-product of
combustion. It is estimated that 1.8 million pounds per year
are released from stationary sources, with 96% coming
from: (1) coal refuse piles, outcrops, and abandoned coal
mines; (2) residential external combustion of bituminous
coal; (3) coke manufacture; and (4) residential external
combustion of anthracite coal. Human exposure to B(a)P
can occur from its presence as a by-product of chemical
production. The number of persons exposed is not known.
Persons working at airports in tarring operations; refuse
incinerator operations; power plants, and coke manufacturers,
may be exposed to higher B(a)P levels than the general
population. Scientists involved in cancer research or in
sampling toxic materials may also be occupationally
exposed. The general population may be exposed to B(a)P
from air pollution, cigarette smoke, and food sources. B(a)
P has been detected in cigarette smoke at levels ranging
from 0.2 to 12.2:g per 100 cigarettes. B(a)P has been
detected at low levels in foods ranging from 0.1 to 50 ppb.
Source
MCLG: zero; MCL: 0.2 μg/L (U.S. EPA, 2000).
Identified in Kuwait and South Louisiana crude oils at concentrations of 2.8 and 0.75
ppm, respectively (Pancirov and Brown, 1975). Emitted to the environment from coke production,
coal refuse and forest fires, motor vehicle exhaust, and heat and power (utility) generation (Suess,
1976). Benzo[a]pyrene is produced from combustion of tobacco and fuels. It is also a component
of gasoline (133–143 μg/L), fresh motor oil (20 to 100 g/kg), used motor oil (83.2 to 242.4
mg/kg), asphalt (≤0.0027 wt %), coal tar pitch (≤1.25 wt %), cigarette smoke (25 μg/1,000
cigarettes), and gasoline exhaust (quoted, Verschueren, 1983). Detected in asphalt fumes at an
average concentration of 14.72 ng/m3 (Wang et al., 2001). Benzo[a]pyrene was also detected in
liquid paraffin at an average concentration of 25 μg/kg (Nakagawa et al., 1978).
Benzo[a]pyrene was reported in a variety of foodstuffs including raw and cooked meat (ND to
12 ppb), fish (0.3–6.9 ppb), vegetables oils (ND-4), fruits (ND to 6.2 ppb) (quoted, Verschueren,
1983).
The concentration of benzo[a]pyrene in coal tar and the maximum concentration reported in
groundwater at a mid-Atlantic coal tar site were 3,600 and 0.0058 mg/L, respectively (Mackay and
Gschwend, 2001). Based on laboratory analysis of 7 coal tar samples, benzo[a]pyrene
concentrations ranged from 500 to 6,400 ppm (EPRI, 1990). In three high-temperature coal tars,
benzo[a]pyrene concentrations ranged from 5,300 to 7,600 mg/kg (Lehmann et al., 1984).
Benzo[a]pyrene was identified in a U.S. commercial creosote at an approximate concentration
of 0.3% (Black, 1982). Nine commercially available creosote samples contained benzo[a]pyrene
at concentrations ranging from 2 to 160 mg/kg (Kohler et al., 2000).
Identified in high-temperature coal tar pitches used in roofing operations at concentrations
ranging from 4,290 to 13,200 mg/kg (Arrendale and Rogers, 1981; Malaiyandi et al., 1982). Lee et
al. (1992a) equilibrated 8 coal tars with distilled water at 25 °C. The maximum concentration of
benzo[a]pyrene observed in the aqueous phase was 1 μg/L.
Schauer et al. (2001) measured organic compound emission rates for volatile organic
compounds, gas-phase semi-volatile organic compounds, and particle phase organic compounds
from the residential (fireplace) combustion of pine, oak, and eucalyptus. The particle-phase
emission rates of benzo[a]pyrene were 0.712 mg/kg of pine burned, 0.245 mg/kg of oak burned,
and 0.301 mg/kg of eucalyptus burned.Particle-phase tailpipe emission rates from gasoline-powered automobiles with and without
catalytic converters were 0.021 and 41.0 μg/km, respectively (Schauer et al., 2002).
Under atmospheric conditions, a low rank coal (0.5–1 mm particle size) from Spain was burned
in a fluidized bed reactor at seven different temperatures (50 °C increments) beginning at 650 °C.
The combustion experiment was also conducted at different amounts of excess oxygen (5 to 40%)
and different flow rates (700 to 1,100 L/h). At 20% excess oxygen and a flow rate of 860 L/h, the
amount of benzo[a]pyrene emitted ranged from 39.4 ng/kg at 650 °C to 690.7 ng/kg at 850 °C.
The greatest amount of PAHs emitted were observed at 750 °C (Mastral et al., 1999).
Environmental fate
The main natural sources of Benzo[a]pyrene(BaP) are forest fires and erupting volcanoes. Anthropogenic sources include the combustion of fossil fuels, coke oven emis- sions, and vehicle exhausts. In surface waters, direct deposition from the atmosphere appears to be the major source of BaP. Benzo[a]pyrene is moderately persistent in the environment. It readily binds to soils and does not readily leach to groundwater, though it has been detected in some groundwater. If released to water, it sorbs very strongly to sediments and particulate matter. In most waters and sediments, it resists breakdown by microbes or reactive chemicals, but it may evaporate or be degraded by sunlight. In water supply systems, it tends to sorb to any particulate matter and be removed by filtration before reaching the tap. In tap water, its source is mainly from PAH-containing materials in water storage and distribution systems.
Purification Methods
A solution of 250mg of benzo[a]pyrene in 100mL of *benzene is diluted with an equal volume of hexane, then passed through a column of alumina, Ca(OH)2 and Celite (3:1:1). The adsorbed material is developed with a 2:3 *benzene/hexane mixture. (It showed as an intensely fluorescent zone.) The main zone is eluted with 3:1 acetone/EtOH, and is transferred into 1:1 *benzene-hexane by adding H2O. The solution is washed, dried with Na2SO4, evaporated and crystallised from *benzene by the addition of MeOH [Lijinsky & Zechmeister J Am Chem Soc 75 5495 1953]. Alternatively it can be chromatographed on activated alumina, eluted with a cyclohexane-*benzene mixture containing up to 8% *benzene, and the solvent evaporated under reduced pressure [Cahnmann Anal Chem 27 1235 1955], and crystallised from EtOH [Nithipatikom & McGown Anal Chem 58 3145 1986]. [Beilstein 5 III 2517, 5 IV 2687.] CARCINOGENIC.
Toxicity evaluation
BaP is purposely synthesized solely for laboratory studies.
The primary source of BaP and many PAHs in air is the
incomplete combustion of wood, gasoline, and other fuels;
in industrial settings where coal is burned; and in natural
burns such as forest fires. BaP can bind to particulate matter,
and inhalation is a common route of exposure. BaP is poorly
water soluble, partitioning strongly to the sediment, and
does not readily bioaccumulate. BaP is found in fossil fuels,
crude oils, shale oils, and coal tars, and is emitted with gases
and fly ash from active volcanoes. If released to air, an
extrapolated vapor pressure of 5.49×10-9 mm Hg at 25°C
indicates BaP will exist solely in the particulate phase in the
atmosphere. Particulate-phase BaP is usually removed from
the atmosphere by wet or dry deposition. BaP contains
chromophores that absorb at wavelengths >290 nm and
therefore is expected to be susceptible to direct photolysis by
sunlight; after 17 h irradiation with light >290 nm, 26.5% of
BaP adsorbed onto silica gel was degraded. If released to soil,
BaP is expected to have very low to no mobility based on
measured soil Koc values of 930–6300. Volatilization from
moist soil surfaces is not expected to be an important
fate process based on a Henry’s Law constant of 4.57×10-7 atm m3 mol1. The stability of BaP in soil is
expected to vary depending on the nature of compounds
accompanying it and the nature and previous history of the
soil; biodegradation half-lives of 309 and 229 days were
observed in Kidman and McLaurin sandy loam soils,
respectively. BaP is expected to adsorb to suspended solids
and sediment based on the measured Koc values, when
released into water. Biodegradation of BaP is possible in
aquatic systems. Volatilization from water surfaces is not
expected to be an important fate process based on this
compound’s Henry’s Law constant. Measured bioconcentration
values ranging from 8.7 to 1×10105 suggest
bioconcentration in aquatic organisms can be low to very
high. Hydrolysis is not expected to be an important environmental
fate process since Benzo[a]pyrene lacks functional
groups that hydrolyze under environmental conditions.
Incompatibilities
Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides, nitrogen dioxide and ozone.
Waste Disposal
Incineration in admixture
with a flammable solvent.
Check Digit Verification of cas no
The CAS Registry Mumber 50-32-8 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 5 and 0 respectively; the second part has 2 digits, 3 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 50-32:
(4*5)+(3*0)+(2*3)+(1*2)=28
28 % 10 = 8
So 50-32-8 is a valid CAS Registry Number.
InChI:InChI=1/C20H12/c1-2-7-17-15(4-1)12-16-9-8-13-5-3-6-14-10-11-18(17)20(16)19(13)14/h1-12H
50-32-8Relevant academic research and scientific papers
Regioselective arene homologation through rhenium-catalyzed deoxygenative aromatization of 7-oxabicyclo[2.2.1]hepta-2,5-dienes
Murai, Masahito,Ogita, Takuya,Takai, Kazuhiko
supporting information, p. 2332 - 2335 (2019/02/27)
Combined use of oxorhenium catalysts with triphenyl phosphite as an oxygen acceptor allowed efficient deoxygenative aromatization of oxabicyclic dienes. The reaction proceeded under neutral conditions and was compatible with various functional groups. Combining this deoxygenation with regioselective bromination and trapping of the generated aryne with furan resulted in benzannulative π-extension at the periphery of the PAHs. This enabled direct use of unfunctionalized PAHs for extension of π-conjugation. Iteration of the transformations increased the number of fused-benzene rings one at a time, which has the potential to alter the properties of PAHs by fine-tuning the degree of π-conjugation, shape, and edge topology.
Bismuth-catalyzed synthesis of polycyclic aromatic hydrocarbons (PAHs) with a phenanthrene backbone via cyclization and aromatization of 2-(2-arylphenyl)vinyl ethers
Murai, Masahito,Hosokawa, Naoki,Roy, David,Takai, Kazuhiko
supporting information, p. 4134 - 4137 (2014/09/30)
The reaction of 2-(2-arylphenyl)vinyl ethers in the presence of a catalytic amount of bismuth(III) triflate gave substituted phenanthrenes in excellent yields under mild reaction conditions. The reaction was also applied to the construction of other polycyclic aromatic hydrocarbons (PAHs), such as chrysene, helicene, and pyrene having a phenanthrene backbone, via regioselective cyclization. This method has the advantages of easy availability of the cyclization precursors, operational simplicity, and high reaction efficiency.
Synthesis of 13C4-labelled oxidized metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene
Wu, Anhui,Xu, Daiwang,Lu, Ding,Penning, Trevor M.,Blair, Ian A.,Harvey, Ronald G.
, p. 7217 - 7233 (2012/09/05)
Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are ubiquitous environmental contaminants that are implicated in causing lung cancer. BaP is a component of tobacco smoke that is transformed enzymatically to active forms that interact with DNA. We reported previously development of a sensitive stable isotope dilution LC/MS method for analysis of BaP metabolites. We now report efficient syntheses of 13C4-BaP and the complete set of its 13C4-labelled oxidized metabolites needed as internal standards They include the metabolites not involved in carcinogenesis (Group A) and the metabolites implicated in initiation of cancer (Group B). The synthetic approach is novel, entailing use of Pd-catalyzed Suzuki, Sonogashira, and Hartwig cross-coupling reactions combined with PtCl2-catalyzed cyclization of acetylenic compounds. This synthetic method requires fewer steps, employs milder conditions, and product isolation is simpler than conventional methods of PAH synthesis. The syntheses of 13C4-BaP and 13C4-BaP-8-ol each require only four steps, and the 13C-atoms are all introduced in a single step. 13C4-BaP-8-ol serves as the synthetic precursor of all the oxidized metabolites of 13C-BaP implicated in initiation of cancer. The isotopic purities of the synthetic 13C 4-BaP metabolites were estimated to be ≥99.9%.
Role of temperature and hydrochloric acid on the formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons during combustion of paraffin powder, polymers, and newspaper
Takasuga, Takumi,Umetsu, Norihito,Makino, Tetsuya,Tsubota, Katsuya,Sajwan, Kenneth S.,Kumar, Kurunthachalam Senthil
, p. 8 - 21 (2008/02/09)
Formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were determined using a laboratory-scale incinerator when combusting materials at different temperatures, different concentrations of hydrochloric acid (HCl), and when combusting various types of polymers/newspaper. Polychlorobenzenes (PCBz), polychlorophenols (PCPhs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and their toxic equivalency (TEQ) and PAHs were highlighted and reported. Our results imply maximum formation of chlorinated hydrocarbons at 400°C in the following order; PCBz≥PCPhs?PCDFs>PCDDs>TEQ on a parts-per-billion level. Similarly, a maximum concentration of chlorinated hydrocarbons was noticed with an HCl concentration at 1000 ppm with the presence of paraffin powder in the following order; PAHs>PCBz≥PCPhs?PCDFs>PCDDs>TEQ an a parts-per-billion level. PAHs were not measured at different temperatures. Elevated PAHs were noticed with different HCl concentrations and paraffin powder combustion (range: 27-32 μg/g). While, different polymers and newspaper combusted, nylon and acrylonitrile butadiene styrene (ABS) produced the maximum hydrogen cyanide (HCN) concentration, concentrations of PCDD/FS, dioxin-like polychlorinated biphenyls (DL-PCBs), and TEQ were in a decreasing order: polyvinylchloride (PVC)newspaperpolyethyleneterephthalate (PET) polyethylene (PE) polypropylene (PP) ABS = blank. Precursors of PCBs were in a decreasing order: PPnylonPEnewspaperABSPVCblankPET. Precursors of PCDD/Fs were in a decreasing order: newspaper PP= nylonPEABSPVC= blankPET. BTX formation was in a decreasing order; PEnylonnewspaperABSPP. PAHs formation were elevated with parts-per-million levels in the decreasing order of PPnylonPE newspaperblankABS PETPVC.
Emission factors and importance of PCDD/Fs, PCBs, PCNs, PAHs and PM 10 from the domestic burning of coal and wood in the U.K.
Lee, Robert G. M.,Coleman, Peter,Jones, Joanne L.,Jones, Kevin C.,Lohmann, Rainer
, p. 1436 - 1447 (2007/10/03)
This paper presents emission factors (EFs) derived for a range of persistent organic pollutants (POPs) when coal and wood were subject to controlled burning experiments, designed to simulate domestic burning for space heating. A wide range of POPs were emitted, with emissions from coal being higher than those from wood. Highest EFs were obtained for particulate matter, PM10, (～ 10 g/kg fuel) and polycyclic aromatic hydrocarbons (～ 100 mg/ kg fuel for ΣPAHs). For chlorinated compounds, EFs were highest for polychlorinated biphenyls (PCBs), with polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) being less abundant. EFs were on the order of 1000 ng/kg fuel for ΣPCBs, 100s ng/ kg fuel for ΣPCNs and 100 ng/kg fuel for ΣPCDD/Fs. The study confirmed that mono- to trichlorinated dibenzofurans, Cl1,2,3DFs, were strong indicators of low temperature combustion processes, such as the domestic burning of coal and wood. It is concluded that numerous PCB and PCN congeners are routinely formed during the combustion of solid fuels. However, their combined emissions from the domestic burning of coal and wood would contribute only a few percent to annual U.K. emission estimates. Emissions of PAHs and PM 10 were major contributors to U.K. national emission inventories. Major emissions were found from the domestic burning for Cl1,2,3DFs, while the contribution of PCDD/F-ΣTEQ to total U.K. emissions was minor.
Experimental study on the removal of PAHs using in-duct activated carbon injection
Zhou, Hong-Cang,Zhong, Zhao-Ping,Jin, Bao-Sheng,Huang, Ya-Ji,Xiao, Rui
, p. 861 - 869 (2007/10/03)
This paper presents the incineration tests of municipal solid waste (MSW) in a fluidized bed and the adsorption of activated carbon (AC) on polycyclic aromatic hydrocarbons (PAHs). An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 US EPA specified PAHs contained in raw MSW, flue gas, fly ash, and bottom ash. The aim of this work was to decide the influence of AC on the distribution of PAHs during the incineration of MSW. Experimental researches show that there were a few PAHs in MSW and bottom ash. With the increase of AC feeding rate, the concentrations of three- to six-ring PAHs in fly ash increased, and the concentration of two-ring PAH decreased. The total-PAHs in flue gas were dominated by three-, and four-ring PAHs, but a few two-, five-ring PAHs and no six-ring PAHs were found. PAHs could be removed effectively from flue gas by using in-duct AC injection and the removal efficiencies of PAHs were about 76-91%. In addition, the total toxic equivalent (TEQ) concentrations of PAH in raw MSW, bottom ash, fly ash, and flue gas were 1.24 mg TEQ kg-1, 0.25 mg TEQ kg-1, 6.89-9.67 mg TEQ kg-1, and 0.36-1.50 μg TEQ N m-3, respectively.
Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China
Chen, Yingjun,Sheng, Guoying,Bi, Xinhui,Feng, Yanli,Mai, Bixian,Fu, Jiamo
, p. 1861 - 1867 (2008/12/21)
Emission factors of carbonaceous particles, including black carbon (BC) and organic carbon (OC), and polycyclic aromatic hydrocarbons (PAHs) were determined for five coals, which ranged in maturity from sub-bituminous to anthracite. They were burned in the form of honeycomb briquettes in a residential coalstove, one of the most common fuel/stove combinations in China. Smoke samples were taken through dilution sampling equipment, with a high volume sampler that could simultaneously collect emissions in both particulate and gaseous phases, and a cascade impactor that could segregate particles into six fractions. Particulate BC and OC were analyzed by a thermal-optical method, and PAHs in emissions of both phases were analyzed by GC-MS. Burning of bituminous coals produced the highest emission factors of particulate matter (12.91 g/kg), BC (0.28 g/kg), OC (7.82 g/kg), and 20 PAHs (210.6 mg/kg) on the basis of burned dry ash-free (daf) coal, while the anthracite honeycomb-briquette was the cleanest household coal fuel. The size-segregated results show that more than 94% of the particles were submicron, and calculated mass median aerodynamic diameters (MMAD) of all particles were under 0.3 μm. Based on the coal consumption in the residential sector of China, 290.24 Gg (gigagrams) of particulate matter, 5.36 Gg of BC, 170.33 Gg of OC, and 4.72 Gg of 20 PAHs mass were emitted annually from household honeycomb-briquette burning during 2000. Anthracite coal should be selected preferentially and more advanced burning conditions should be applied in domestic combustion, from the viewpoint of both climate change and adverse health effects.
Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator
Lin, Chiou-Liang,Wey, Ming-Yen,Cheng, Han-Tsung
, p. 911 - 922 (2007/10/03)
The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.
Semivolatile and volatile compounds in combustion of polyethylene
Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
, p. 615 - 627 (2007/10/03)
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
Emissions of air pollutants from household stoves: Honeycomb coal versus coal cake
Ge, Su,Xu, Xu,Chow, Judith C.,Watson, John,Sheng, Qing,Liu, Weili,Bai, Zhipeng,Zhu, Tan,Zhang, Junfeng
, p. 4612 - 4618 (2007/10/03)
Domestic coal combustion can emit various air pollutants. In the present study, we measured emissions of particulate matter (PM) and gaseous pollutants from burning a specially formulated honeycomb coal (H-coal) and a coal cake (C-coal). Flue gas samples for PM2.5, PM coarse (PM 2.5-10), and TSP were collected isokinetically using a cascade impactor; PM mass concentrations were determined gravimetrically. Concentrations of SO2, NOx, and ionic Cr(VI) in PM were analyzed using spectrometric methods. Fluoride concentrations were measured using a specific ion electrode method. PM elemental components were analyzed using an X-ray fluorescence technique. Total (gas and particle phase) benzo[a]pyrene (BaP) concentration was determined using an HPLC/fluorescence method. Elemental and organic carbon contents of PM were analyzed using a thermal/optical reflectance technique. The compositional and structural differences between the H-coal and C-coal resulted in different emission characteristics. In generating 1 MJ of delivered energy, the H-coal resulted in a significant reduction in emissions of SO2 (by 68%), NOx (by 47%), and TSP (by 56%) as compared to the C-coal, whereas the emissions of PM2.5 and total BaP from the H-coal combustion were 2-3-fold higher, indicating that improvements are needed to further reduce emissions of these pollutants in developing future honeycomb coals. Although the H-coal and the C-coal had similar emission factors for gas-phase fluoride, the H-coal had a particle-phase fluoride emission factor that was only half that of the C-coal. The H-coal had lower energy-based emissions of all the measured toxic elements in TSP but higher emissions of Cd and Ni in PM2.5.
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