Terms Of CO Emissions Research Articles

Design of Metallic Catalytic Converter using Pareto Optimization to Improve Engine Performance and Exhaust Emissions

In this paper, Metallic Catalytic Converter (MCC) is installed in motorcycle exhausts to produce the minimum CO as well as to produce the optimum engine power. The results from previous research were collected and then used to predict the best MCC design using the Artificial Neural Network Multi-Objective Genetic Algorithm (ANN-MOGA). In addition, the ANN parameter tuning process was also carried out using the Taguchi method to find the initial weighting and bias that is able to provide the best and the most stable performance to predict the best MCC design. The best two sets of design solutions out of 70 sets of Pareto solutions were obtained by ANN-MOGA. Those two MCC designs are the optimum emission design and the optimum multi-objective design. The verification results show that the optimum multi-objective design tends to be superior in terms of CO emissions and engine power. In terms of CO emissions, the optimum multi-objective design gets a larger S/N ratio of -10.98, while the optimum emission design only gets an S/N ratio of -11.21. Meanwhile, in terms of engine power, the optimum multi-objective design gets a larger S/N ratio of 16.13, while the optimum emission design only gets an S/N ratio of 15.86 S/N. It is in line with the ANOVA test results which show that the optimum multi-objective design is proven to be better than the optimum emission design.

Energy efficiency study of household natural gas burner using pot-bottom shield and modified pot arrangement

The study aims to design and evaluate practically applicable pot-bottom shield and finned-pot in different pot-shield arrangements for better thermal and emission performances of a conventional household radial flow NG burner to lessen the household cooking energy consumption. Eleven sets of perforated hollow cylindrical pot-bottom shields having different heights were fabricated from thin metal sheet with a provision of secondary combustion air. One of the two identical flat bottom pots was converted to spot welded finned pot. The thermal and emission performances of the NG burner were then evaluated following the standard water boiling test (WBT) protocol with four different pot arrangements, namely ordinary flat bottom pot without shield and with shield and spot welded finned pot without shield and with shield at eleven different loading heights (from 2.5 cm to 7.5 cm) and six different NG supply pressures (0.4, 0.6, 1.0, 1.4, 1.8 and 2.0 kPa) keeping the burner primary air opening fixed at 50%. The corresponding NG flow rates at SATP were 4.23, 4.30, 4.70, 4.84, 4.94, 5.15 L/min for 0.4, 0.6, 1.0, 1.4, 1.8, and 2.0 kPa, respectively. It was found that a simple inclusion of a pot-bottom shield can dramatically improve the thermal efficiency of a natural gas cooking system for the both type of pots. A 20% improved thermal efficiency was evaluated for the NG burner with ordinary pot and pot-bottom shield arrangement at 0.6 kPa pressure and 3 cm loading height corresponded to the highest efficiency of the burner at base setting (burner with ordinary pot at 0.6 kPa NG pressure and 4 cm loading height). It was also found that the operation of the burner at its highest thermal efficiency was still within the safe operation limit in terms of CO emission in comparison to international standards.

Diesel-Biodiesel-Water Fuel Nanoemulsions for Direct Injection and Indirect Injection Diesel Engines: Performance and Emission Characteristics.

An experimental research is assessed to examine the engine performance and exhaust emissions of direct injection (DI) and indirect injection diesel (IDI) engines fueled with petroleum diesel, biodiesel, and nanoemulsion fuel. The nanoemulsion fuel was produced using a hydrodynamic cavitation reactor. These three fuels were used to study the exhaust emissions, brake power, brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), and exhaust gas temperature at engine speeds ranging from 1100, 1400, 1700, 2000, and 2300 rpm with engine loads of 25, 50, and 75%. Furthermore, three fuels were burned in two types of combustion engines such as DI and IDI diesel engines under identical conditions. The finding showed that using DI and IDI engines influenced the magnitude of emissions as well as the performance with different speeds and loads. By comparing the performance of DI and IDI engines at a maximum engine load of 75%, the most concerning parameter among the efficiency of an engine of BTE of diesel, biodiesel, and nanoemulsion fuel from the DI engine was higher at 24.19, 24.83, and 20.76%, respectively, than that of the IDI engine at 2300 rpm engine speed. At the maximum load and speed of engines, the BSFC of diesel, biodiesel, and nanoemulsion fuel in the DI engine were 4.44, 23.73, and 20% lower than in the IDI engine, respectively. Emission results of the DI and IDI engines were analyzed at 75% load and 2300 rpm speed. The results demonstrated that emissions of NOx from nanoemulsion fuel from the IDI engine was significantly reduced by 82.46% when the values were compared to the DI engine. In terms of CO emissions, the IDI engine emits significantly less than the DI diesel engine. The CO emissions of diesel, biodiesel, and nanoemulsion fuel in the IDI engine were 69.02, 28.95, and 48.75% lower than those in the DI engine, respectively. The studies conclude that the emissions from IDI engines clearly show that pollution from exhaust emissions can be reduced to a low level compared to the DI engine. However, when high-performance engines are considered, the DI engine is recommended rather than the IDI engine.

Experimental investigation on the stability of turbulent swirling methane/air-O2 flames

This work investigates the combustion characteristics of CH4-air/O2 turbulent swirling flames in a co-axial burner with radial fuel injection. The burner configuration consists of two coaxial tubes with a swirler positioned within the annular space for the oxidizer flow. The central tube delivers the fuel through eight holes placed that are uniformly distributed along the circumference of the inner tube nearby the burner exit. The experiments were carried out in a 25-kW combustion chamber of dimensions 50x50x120 cm3. Stereo Particle Image Velocimetry (SPIV) was used to characterize the different velocity fields, whereas the OH* Chemiluminescence is employed to examine the flame structure and stability. The exhaust gas compositions were measured using multi-gas analyzers. The structure and stability of flames, temperature evolutions, CO2, and pollutant emissions (NOx, CO) were examined under different parameters, such as: oxygen enrichment (21–50 %), global equivalence ratio (0.4–1), swirl number (0.5 and 1.4), injection type of fuel (axial or radial). Experiments were conducted at a constant power of 9.41 kW and variable powers in the range from 9.41 to 22.42 kW. The present results show that the oxygen enrichment decreases the lift-off height and enhances the flame stability using constant flame power. Increasing the swirl number improves the flame stability and produces a better attached flame. At constant flame power and variable oxidizer flow rate, a high oxygen concentration yields lower NOx emissions. For lean combustion with excessive oxygen enrichment over 35 %, retaining the same flame power leads to a significant decrease in NOx emissions. The radial injection of CH4 does not affects the NOx emissions, however, the axial injection is shown to be advantageous in terms of CO emissions in the present studied configurations.

Experimental Study of the Influence of Natural Gas Constituents on CO Emission from Chinese Gas Cooker

In China, it has become a more common practice to introduce natural gases from different sources into the same distribution system to improve supply security and reliability. Variable gas constituents may cause a negative impact on the performance of domestic gas appliances. This paper aims to study the CO emission of a Chinese gas cooker under different constituents of natural gas. A typical Chinese gas cooker with two burners, each of which has a nominal heat input of 3.8 kW, was selected. One of the burners was modified to a forced-mixed mode to replace primary air injection. Within operational ranges corresponding to the permissible Wobbe index—namely, primary air coefficients and heat inputs—the equivalence between original gas and the CH4/C3H8/N2 three-component mixture in terms of CO emission was experimentally validated. Then, different three-component mixtures were input into the other unmodified burner, which operates under injected primary air, to investigate how the CO emission changed with different gas constituents. It was found that the CO emission of a natural gas and a CH4/C3H8/N2 three-component mixture, in terms of CO emission, were equivalent. The combination of the two indexes, W and PN, can describe the CO emission from a gas cooker accurately. By means of a three-component mixture, the empirical formula, which can correlate CO and the gas property parameters, was proposed. A set of equal-CO lines was revealed for a given initial primary air adjustment. Finally, a feasible approach to manage gas quality management in China was put forward, and the conclusion can help control the CO emission of gas cookers and improve indoor air quality.

Analyzing Of Exhaust Gas of Single Cylinder Diesel Engine by Injection of Sunflower 0il (Bio-Fuel)

Many attempts to use vegetable oils as fuel have been performed since the early days of the Diesel engine. When a Diesel engine is used with vegetable oil fuel for a short period of time, the performance and global efficiency are usually very close to Diesel fuel. However, during long-term engine tests with vegetable oils as fuel, heavy deposits build-up can be observed in the combustion chamber. These deposits can lead to engine breaks. A fuel droplet vaporization experiment proved that the deposits build-up is mainly controlled by the combustion chamber temperature. A new thermally insulated combustion chamber made it possible to raise the combustion chamber wall temperature. With this combustion chamber, the deposits were greatly reduced. To use vegetable oils as fuel, DI Diesel engines need to be redesigned to accommodate the specificity of the vegetable oils combustion, one possibility is to use a thermally insulated combustion chamber. This paper is related with performance analysis of Compression Ignition Engine using sunflower oil for different engine load from 1 kg to 10 kg and different portmanteau ratios like Portmanteau:1000, Portmanteau:7525, Portmanteau:5050, Portmanteau: 2575, and Portmanteau:0010. With the injection of above Portmanteau in different portmanteau ratio and at different load we found the exhaust emission in terms of CO emission, HC emission, Exhaust gas temperature and smoke density and performance analysis of the bio-fuel.

Structures and performances of laminar impinging multiple premixed LPG–air flames

Three different imaging techniques were utilized to study the laminar, impinging, multiple, premixed liquefied petroleum gas (LPG)–air flames for simulating the premixed impinging flames of practical cooking burners. Two line-of-sight observation techniques are introduced, i.e. direct photography of a typical visible flame and the imaging of flame chemiluminescence, whereas the spatially resolved imaging is carried out by means of the OH-PLIF technique as the in situ visualization. Effects of the key parameters of heating height (H/D) and inter-port spacing (S/Do) on the flame structure and flame interaction are systematically studied and compared. The burner’s performances in terms of CO emissions and thermal efficiency are experimentally studied to correlate with the flame structure. Among the three techniques, the OH-PLIF measurement is the most reliable technique to uncover the combustion situation existing in the flames. H/D is a major parameter controlling the multiple flame structure and the corresponding burner’s performance, whereas S/Do has a less degree effect as compared with H/D. The optimum condition is found at H/D=2.1 and S/Do=1.5, where OH-PLIF profiles are well correlated with the corresponding burner’s performance. This study results in better understanding of insights into the structure of the multiple premixed impinging flames, which is valuable for further work of designing an efficient, practical cooking burner.

Performance evaluation and emission characterisation of three kerosene stoves using a Heterogeneous Stove Testing Protocol (HTP)

The combustion of kerosene fuel in poorly designed cookstoves is a major domestic source of poor indoor air quality and burn injuries in the developing world. It is argued that these challenges are best addressed by the development and dissemination of clean, safe and efficient cookstoves. In this study, three kerosene stoves including two wick stoves and one pressurised stove were tested for thermal performance and CO gas emissions using the Heterogeneous stove Testing Protocol (HTP) developed at the SeTAR Centre, University of Johannesburg. Results from the testing showed that the diameter of the pot had little effect on the performance of the tested kerosene stoves in terms of CO emissions, but it did have an effect on the thermal efficiency at the high power setting. Power setting was found to influence the thermal efficiency and combustion performance of all stoves tested, indicating the need for assessment of the appliances across the full range of power settings (where feasible). The pressurised stove had lower CO emissions compared with the wick stoves. Conversely, the wick stoves depicted lower specific times to boil water and higher fuel efficiencies. These results provide essential information to stove designers, regulators and authorities interested in the dissemination of improved kerosene stoves. The variation of emissions and performance across the power band may be useful for improving national standards by correctly characterising novel technologies and improving the design of existing appliances under different operating conditions. Implications of improved kerosene stoves are improved health, improved access to modern energy, reduced fuel consumption and a reduction in energy poverty.

Natural gas combustion catalysts for environmental-friendly domestic burners

The present work deals with the analysis of low-environmental-impact premixed metal fibre burners (Fe–Cr–Al fibre mats) for natural gas combustion, characterized by a satisfactorily combustion performance. In particular, perovskite- and mixed oxides-based catalysts, in synergism with Pd, were suitably developed at powder level and subsequently deposited over metal fibre mattress. New catalytic burners based on LaMnO 3-ZrO 2, CeO 2-ZrO 2, BaCeO 3-ZrO 2 and Pd/LaMnO 3-ZrO 2, Pd/CeO 2-ZrO 2, Pd/BaCeO 3-ZrO 2 catalysts were studied determining, first of all, the optimal operating conditions for catalysts preparation via the solution combustion synthesis (SCS). After preliminary investigations at powder level, the catalysts were then deposited over metal fibre mats to obtain premixed burners for household appliances. The resulting structured catalysts were then tested on a commercial domestic boiler under realistic operating conditions. The obtained results with the Pd-based catalytic burners showed better performances compared with those of the commercial burner, in terms of CO emissions. The NO emissions, however, resulted somehow increased, especially at the low thermal power rates and air excess, whereas they slightly decreased at high air excess. The most interesting results in terms of CO emission reduction were obtained with the Pd/CeO 2-ZrO 2 catalyzed burner.