Emission Characteristics Of CO Research Articles

Experimental Research on Influence of Vehicle Running Conditions on Emissions

Experiments were done to the same car with engine capacity of 1.6 liter on three typical road conditions in Shenzhen for emission characteristics of CO、HC and NOx with SEMTECH-DS manufactured by Sensors Company in USA. Through analysis on the experimental data it is indicated that emission factors with the measurement unit of g/km produced inflection points at the vehicle speed of 7.5～10 Km/h, and its variable rate is big at low speed interval and stable at high speed interval; average emission factors of CO and HC for car running in secondary city main roads is two or five times than those in city main roads; emissions of CO and HC of car at idle and low speed conditions take higher proportion.

Nozzle effect on heat transfer and CO emission of impinging premixed flames

Experiments were carried out to investigate the heat transfer and CO emission characteristics of a premixed LPG/air circular flame jet impinging upwards normal to a flat plate. The effects of nozzle diameter and nozzle arrangement on the heat transfer and CO emission under different fuel/air mixture flow rates ( Q mix), equivalence ratios ( Ф) and normalized nozzle-to-plate distances ( H/ d) were examined. For the effect of nozzle diameter, burners of nozzle diameters of d = 7.9, 9 and 10 mm were used, and for the effect of nozzle arrangement, a twin-nozzle burner and a triple-nozzle burner, each with a cross-sectional area equal to that of the 9 mm diameter burner, were investigated under different normalized jet-to-jet spacing, S/ d, of 3, 5 and 7. The heat transfer rate and CO emission index (EICO) are enhanced significantly with the decrease in the nozzle diameter for the single-nozzle flames. For the twin- and triple-nozzle flames, when the other operational conditions including Q mix, Ф and H/ d are invariant, the moderate S/ d of 5 gives the highest heat transfer rate, whereas the EICO increases with increasing S/ d. Comparison of the flames from all the burners shows that the highest heat transfer rate and EICO are obtained on the single-nozzle burner with the smallest nozzle diameter while the lowest heat transfer rate and EICO are obtained on the triple-nozzle burner with the smallest S/ d.

Suggestion on the Simultaneous Reduction Method of CO and NOx in Premixed Flames for a Compact Heat Exchanger

This study focused on the design of a domestic gas-condensing boiler, in which the burner and the heat exchanger were contained within a small combustion chamber. A method was suggested for the simultaneous reduction of CO and NOx by optimum placement of the heat exchangers in the postflame region of the CH4/air premixed flame. In this study, the effect of the location of heat exchangers on NO and CO emission characteristics was numerically simulated using a quasi-one-dimensional model. To validate this effect, the distance (L1) between the burner exit and the first heat exchanger and the distance (L2) between the first and second heat exchangers were varied. The radiative heat loss and the effective heat-loss coefficients (heff,exch) for the conductive and convective heat losses were also considered. In general, the NO mole fraction decreased as the distance L1 decreased. That is to say, when the burner exit was closer to the flame, it reduced the peak temperature, which decreased the formation of thermal NO. However, the CO mole fraction increased, as opposed to the NO mole fraction, as the distance L1 decreased, because the temperature was already below 1200 K. The amount of CO production continuously decreased because of the increased oxidation of CO as the distance L2 increased, whereas the amount of NO production showed little change. Consequently, the location of heat exchangers directly affected the amount of NO and CO production. The NO production was mainly controlled by the distance L1, whereas the CO production was controlled by the distance L2. The distance L1 should be set up close to the flame to reduce NO production, and the distance L2 should be long enough to guarantee the sufficient conversion time from CO to CO2 for the purpose of reducing CO emissions.

HC and CO Emission Characteristics in a DME PCI Engine

HC and CO Emission Characteristics in a DME PCI Engine

Theoretical and experimental study on the emission characteristics of waste plastics incineration by modified O 2/RFG combustion technology

For mitigating the emission of greenhouse gas CO 2 from general air combustion systems, a clean combustion technology O 2/RFG is in development. The O 2/RFG combustion technology can significantly enhance the CO 2 concentration in the flue gas; however, using almost pure oxygen or pure CO 2 as feed gas is uneconomic and impractical. As a result, this study proposes a modified O 2/RFG combustion technology in which the minimum pure oxygen is mixed with the recycled flue gas and air to serve as the feed gas. The effects of different feed gas compositions and ratios of recycled flue gas on the emission characteristics of CO 2, CO and NO x during the plastics incineration are investigated by theoretical and experimental approaches. Theoretical calculations were carried out by a thermodynamic equilibrium program and the results indicated that the emissions of CO 2 were increased with the O 2 concentrations in the feed gas and the ratios of recycled flue gas increased. Experimental results did not have the same trends with theoretical calculations. The best feed gas composition of the modified O 2/RFG combustion was 40% O 2 + 60% N 2 and the best ratio of recycled flue gas was 15%. As the O 2 concentration in feed gas and the ratio of recycled flue gas increased, the total flow rates and pressures of feed gas reduced. The mixing of solid waste and feed gas was incomplete and the formation of CO 2 decreased. Moreover, the emission of CO was decreased as the O 2 concentration in feed gas and the ratio of recycled flue gas increased. The emission of NO x gradually increased with rising the ratio of recycled flue gas at lower O 2 concentration (<40%) but decreased at higher O 2 concentration (>60%).

Emission characteristics of coal combustion in different O 2/N 2, O 2/CO 2 and O 2/RFG atmosphere

This study investigates the emission characteristics of CO 2, SO 2 and NOx in the flue gas of coal combustion by varying the compositions and concentrations of feed gas (O 2/CO 2/N 2) and the ratios of recycled flue gas. The differences between O 2/recycled flue gas (O 2/RFG) combustion and general air combustion are also discussed. Experimental results indicate that the maximum concentration of CO 2 in O 2/CO 2 combustion system is 95% as the feed gas is 30% O 2/70% CO 2. The average concentration of CO 2 in the flue gas of O 2/CO 2 coal combustion system is higher than 90% and much higher than that of O 2/N 2 coal combustion system. This high concentration of CO 2 is beneficial for the separation of CO 2 from the flue gas by adsorption or absorption technologies. The maximum concentration of CO 2 in O 2/N 2 combustion system is only 34% at the feed gas 50% O 2/50% N 2, the concentration of CO 2 is increased with the concentration of O 2 in feed gas. By O 2/CO 2 combustion technology, higher concentration of SO 2 is produced as the feed gas is 30% O 2/70% CO 2 or 40% O 2/60% CO 2, while higher concentration of NOx is produced as the feed gas is 20% O 2/80% CO 2 or 50% O 2/50% CO 2. The mass flow rates of CO 2, SO 2 and NOx in the flue gas are all increased with the ratio of recycled flue gas except for the feed gas 20% O 2/80% CO 2. The enhanced mass flow rates of air pollutants in such O 2/RFG combustion system are also beneficial for improving the control efficiencies of air pollution control devices. By O 2/N 2 combustion technology, higher concentrations of SO 2 and NOx are produced as the feed gas is 21% O 2/79% N 2. The results also indicate that the formation of NOx in general air combustion system is higher than that in O 2/RFG or O 2/CO 2 combustion system.

Effects of N2 and CO2 mixing on ignition and combustion in a homogeneous charge compression ignition engine operated on dimethyl ether

The control of ignition timing and combustion duration over a wide range of engine speeds and loads in a homogeneous charge compression ignition (HCCI) engine is one of the barriers to the realization of this type of engine. Application of exhaust gas recirculation (EGR) is a promising option to control ignition timing, extend combustion duration, and suppress knock-like combustion. In this study, the effects of the mixing of N2 and CO2, major components of exhaust gas, with the fuel-air mixture on the heat release of the cool flames and the emission characteristics of CO were investigated by experiment and computation. The heat release of the cool flames was reduced with N2 mixing; however, it increased with CO2 mixing. From the systematic experiments and chemical kinetic computations, it was confirmed that the amount of heat release from the cool flames depends strongly on the concentration of O2 at the onset of cool flame. The dominant pathway for CO oxidation is the reaction of CO + OH = CO2 + H, where the H atoms produced react with O2 molecules and produce OH + O or HO2. The CO oxidation becomes active as the branching rate to OH + O is increasing. However, the branching rate to HO2 was increased with the addition of CO2 into the mixture, resulting in higher CO emission. Though the mixing of CO2 is effective in suppressing knock-like combustion owing to its small specific heat ratio and large heat capacity, it has an inferior effect on CO emission.

다수 상호작용 화염의 공해배출물 특성

It has been reported that the interacting multiple jet flames of propane fuel are not extinguished even at the choking velocity at the nozzle exit if eight small nozzles are arranged along the imaginary circle of 40~72 times the diameter of single nozzle. In this research, experiments were conducted to know the NO and CO emission characteristics of the interacting flames. Measurements along the centerline of the flame revealed that decrease in CO concentration was followed by the NO decrease and O₂ increase. It was found that interacting flame emitted less NO than that of similar area single jet flame. Also, NO emission of partially premixed interacting flame was decreased up to 17% of that of non-premixed multiple jet flame. Though the mechanism of the NO reduction was not clear from this experiment, it's been shown that partially premixed multiple jet flames could be used to achieve clean and highly stable combustion.

Effects of N_2/CO_2 Addition on Ignition and Combustion in Homogeneous Charge Compression Ignition Engine Operated on Dimethyl Ether(HCCI, Effect of Fuel and Additives)

The control of ignition timing and combustion period over a wide range of engine speeds and loads in HCCI engine is one of the barriers to the realization of the engine. Application of exhaust gas recirculation, EGR, is thought to be a promising option to control ignition timing, to extend combustion period and to suppress knock like combustion. In this study, the effects of N_2/CO_2, major components of exhaust gas, addition on the heat release of cool flame and the emission characteristics of CO were investigated from experiments and computations. The heat release of cool flame was reduced with N_2 addition, however, it increased with CO_2 addition. From the systematic experiments and chemical kinetic computations, it was confirmed that the amount of heat release at cool flame depends strongly on the concentration of O_2 at cool flame onset. The dominant path for CO oxidation is the reaction of CO + OH = CO_2 + H. The produced H atoms react with O_2 molecules and produce OH + O or HO_2. The CO oxidation becomes active as increasing the blanching rate to OH + O. However, with the addition of CO_2 to the mixture, the branching rate to HO_2 was increased, resulting in a higher CO emission. Though the addition of CO_2 is effective in suppressing a knocking from its large heat capacity, it has an inferior effect on CO emission.

Emission characteristics of CO, NOx, SO2and indications of biomass burning observed at a rural site in eastern China

Atmospheric O3, CO, SO2, and NOy* (NOy* ≈ NO + NO2+ PAN + organic nitrates + HNO3+ N2O5+ ⋯) were measured in 1999–2000 at a rural/agricultural site in the Yangtze Delta of China. In this paper we analyze the measurement results to show the emission characteristics of the measured gases and to infer relevant emission ratios. Positive correlations were found between CO and NOy* with a slope (Δ[CO]/Δ[NOy*]) of 36 (ppbv/ppbv) for the winter and nighttime measurements. The ratio is considerably larger than that (≈10 ppbv/ppbv) observed in the industrialized countries. The highest CO/NOy* ratio (30–40 ppbv/ppbv) occurred in September–December 1999 and June 2000. The good correlation between CO and the biomass burning tracer CH3Cl and the lack of correlation with the industrial tracer C2Cl4suggests that the burning of biofuels and crop residues is a major source for the elevated CO and possibly for other trace gases as well. The average SO2to NOy* ratio was 1.37 ppbv/ppbv, resulting from the use of relatively high‐sulfur coals in China. The measured SO2/NOy* and ΔCO/ΔNOy* were compared with the respective ratios from the current emission inventories for the study region, which indicated a comparable SO2/NOxemission ratio but a large discrepancy for CO/NOx. The observed CO to NOy* ratio was more than 3 times the emission ratio derived from the inventories, indicating the need for further improvement of emission estimates for the rural/agricultural regions in China. Additional research will be needed to study the implications of rural emissions to atmospheric chemistry and climate on both regional and global scales.