Hsiao-Hsuan Mi

Effect of fuel aromatic content on PAH emission from a heavy-duty diesel engine

Polycyclic aromatic hydrocarbons (PAHs) emission tests for a heavy-duty diesel engine fueled with blend base diesel fuel by adding batch fractions of poly-aromatic and mono-aromatic hydrocarbons, Fluorene and Toluene, respectively, were simulated to five steady-state modes by a DC-current dynamometer with fully automatic control system. The main objective of this study is to investigate the effect of total aromatic content and poly-aromatic content in diesel fuels on PAH emission from the HDD engine exhaust under these steady-state modes. The results of this study revealed that adding 3% and 5% (fuel vol%) Fluorene in the diesel fuel increases the amount of total-PAH emission by 2.6 and 5.7 times, respectively and increases the amount of Fluorene emission by 52.9 and 152 times, respectively, than no additives. However, there was no significant variation of PAH emission by adding 10% (vol%) of Toluene. To regulate the content of poly-aromatic content in diesel fuel, in contrast to the total aromatic content, will be more suitable for the management of PAH emission.

PAH emission from the incineration of waste oily sludge and PE plastic mixtures

A batch-type, controlled-air incinerator was used for the treatment of oily sludge and polyethylene (PE) plastic mixtures. The concentration and composition of 21 individual PAHs (polycyclic aromatic hydrocarbons) in the raw wastes, flue gas (gas and particle phases) and ash were determined. Stack flue-gas samples were collected by a PAH stack-sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatograph and a gas chromatography/mass spectrometer. Due to incomplete combustion, PAH content in the feeding wastes have a strong influence on PAH emission in both stack flue gas and ash residue. With the oily sludge in the feeding waste mixtures, the input mass of lower molecular weight PAHs — Nap, AcPy, Acp, Flu, PA, Ant and FL — was contributed mainly by liquid diesel, while the input mass of higher molecular weight PAHs — Pyr, CYC, CHR, BbF, BkF, BeP, BaP, PER, IND, DBA, BbC, BghiP and COR — was primarily contributed by the oily sludge. For the distribution of individual PAH mean output mass, lower molecular weight PAHs — Nap, AcPy, Acp and Flu — have > 87% of their mass discharged by the stack flue gas. However, the higher molecular weight PAHs — Ant, FL, CHR, BbF, BeP, BaP, PER, IND, DBA, BbC, BghiP and COR — have significant mass fractions (>18%) discharged by the ash residue. The total-PAH output/input mass ratios were between 0.00103 and 0.00360 and averaged 0.00203. This result indicated that the depletion of PAH mass in the combustion process was very significant. The PAH content in the fuel during the combustion process is the control factor of PAH emission. The co-combustion of oily sludge with plastic is a potential method of reducing the PAH emission and of saving the consumption of auxiliary fuel.

PAH emission from the industrial boilers

Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO+NG) and a co-combustion of coke oven gas and blast furnace gas (COG+BFG) boilers. PAH samples from the stack flue gas (gas and particle phases) of these 25 boilers were collected by using a PAH stack sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Total-PAH concentration in the flue gas of 83 measured data for these 25 boiler stacks ranged between 29.0 and 4250 microg/m(3) and averaged 488 microg/m(3). The average of PAH-homologue mass (F%) counted for the total-PAH mass was 54.7%, 9.47% and 15.3% for the 2-ring, 3-ring and 4-ring PAHs, respectively. The PAHs in the stack flue gas were dominant in the lower molecular weight PAHs. The emission factors (EFs) of total-PAHs were 13,300, 2920, 2880 and 208 microg/kg-fuel for the heavy oil, diesel, HO+NG and COG+BFG fueled-boiler, respectively. Nap was the most predominant PAH occurring in the stack flue gas. In addition, the EF of 21 individual PAHs in heavy-oil boiler were almost the highest among the four various fueled-boilers except for those of FL and BkF in the diesel boiler. Furthermore, the EF of total-PAHs or BaP for heavy oil were both one order of magnitude higher than that for the diesel-fueled boiler.

PAH emissions influenced by Mn-based additive and turbocharging from a heavy-duty diesel engine

A manganese-based additive was used in this study to investigate the effects on the polycyclic aromatic hydrocarbons (PAHs) emission from a natural-aspirated heavy-duty diesel-powered engine. A similar turbocharged engine was tested and compared with the natural-aspirated one for the PAH emission. The concentrations of 21 individual PAHs (gas + particle phases) and the metal element (Mn) of the particulate from the engine exhaust and in the diesel fuel, respectively, were determined. Engine exhaust (PAHs and Mn) was collected over the modified JAMA J-13 mode by a PAH sampling system. By adding 400 mg/kg of Mn-based additive in the diesel, the reduction fraction of mean total-PAH (gas plus particle phase) emission was 37.2%, while for the 10 higher molecular weight (HMW) PAHs, the mean reduction fraction was 64.5%. These results indicate that the Mn-based additive in the diesel engine can act as a catalyst enhancing the oxidation process and reducing a considerable amount of PAH emission. In addition, the amount of 10 HMW PAH emission from the turbocharged engine averaged 92.4% of magnitude lower than that of the natural-aspirated engine. This result revealed that the turbocharged engine has higher pressure and temperature and thus makes a more complete combustion of the fuel.

Effect of the Gasoline Additives on PAH Emission

PAH emission from the powered engines fueled by a 95 leadfree gasoline (95-LFG), a 92 leadfree gasoline (92-LFG) and a Premium leaded gasoline (PLG) with two gasoline additives (SA and SB) were collected using a PAH sampling system with a particulate interception device. Twenty one PAHs were analyzed primarily by an GC/MS, while eight metal elements were determined mainly by an ICP-AES. This investigation showed that the gasoline additives contain more amounts of carcinogenic PAHs than gasolines do. Blending these additives do raise the PAH content in the gasolines, simultaneously, will emit more amount of PAHs from the tailpipe of engine exhaust. It is suggested that before a gasoline additive is commercialized, an assessment on its PAH emission should be evaluated to make sure that the additive will not emit more PAHs and cause adverse effect on public health.

PAH Emission from a Gasoline-Powered Engine

Abstract A gasoline powered engine operated on a dynamometer was used to investigate the PAH (Polycyclic Aromatic Hydrocarbons) emission. A 95‐leadfree gasoline (95‐LFG) and a premium leaded gasoline (PLG) were used as power‐fuels. The engine was simulated for the idling condition and for the cruising speeds at 40, 80 and 110 km/hr. The concentrations of 21 individual PAHs in the engine exhaust, gasolines, and the ambient air were determined. Engine exhaust samples were collected by a PAH sampling system, while the ambient air sample was collected by using a standard PS‐1 sampler. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Naphthalene (Nap) has the highest concentration in the liquid phase of both 95‐LFG and PLG, in which it accounts for respectively 98.3% and 76.6% of the total PAH. In term of the mean fraction of the total PAHs entering the 95‐LFG and PLG engines, the ambient air contributed less than 0.108% and 0.012%, respectively. Gasoline is...

Dry deposition of sulfate-containing particulate at the highway intersection, coastal and suburban areas

Sulfate-containing aerosol (SCA) dry deposition at the highway intersection, coastal location, and suburban area in Taiwan were analyzed and compared. Sampling was accomplished with a surrogate surface technique. Samples particles were coated with barium chloride (BaCl(2)) in a vacuum evaporator and then exposed to a relative humidity of 85% for 2 h to form distinctive products of SCAs. Treated samples were examined by a scanning electron microscopy. SCA dry deposition fluxes were 10.2, 4.1, 3.4 microgm(-2)s(-1) and nonsulfate-containing aerosol (NSCA) dry deposition fluxes were 23.3, 8.2, 13.5 microgm(-2)s(-1) at the highway intersection, coastal, and suburban areas. At the highway intersection, both SCA and NSCA dry deposition fluxes were much higher than those at the other two sites. The dry deposition of particles was also analyzed with a traditional technique. The number median diameters (NMDs) of SCA were 0.41, 0.82, and 1.2 mum at the highway intersection, coastal, and suburban sites, respectively. The highway intersection site had a small NMD, which showed that most sulfate-containing deposited aerosols existed in fine diameter range. The mass median diameters (MMDs) of SCA were 8.8, 19.5, and 14.9 mum at the highway intersection, coastal, and suburban sites, which were much higher than NMDs. Average numbers of SCAs in total particulate were 33%, 33%, and 22% at the highway intersection, coastal and suburban areas Most deposited particulates were nonsulfate-containing at the three sampling sites. SCAs less than 10 mum contributed 29%, 8%, and 7% to the total dry deposition at the highway intersection, coastal, and suburban areas, respectively. The contribution of fine particulate was significantly higher at the highway intersection site.