Lower Gaseous Emissions Research Articles

Fuel consumption and exhaust emissions from Euro 6d vehicles fueled by innovative LPG/DME blend

The aim of this research was to investigate the exhaust emissions from vehicles when fueled by a new and fully renewable fuel if made of bio-LPG and renewable dimethyl ether (DME), in comparison with standard gasoline. For this purpose, DME was mixed with liquefied petroleum gas (LPG) and used to fuel three bi-fuel LPG/gasoline spark-ignition engines light-duty vehicles. The suitable fuel blend was selected based on several octane tests using CFR engines. Exhaust emissions were tested over the WLTC and over the hot-start CADC cycles, as well as on the road. All Euro 6 standards were well fully met over the WLTC with both fuels. Switching from gasoline to LPG/DME fueling, the CO and NOx emission factors increased for two vehicles, whereas THC and NMHC decreased. Regarding particulates, for two vehicles the emission factors decreased, too. Generally, when the vehicles were driven on the CADC, lower gaseous emissions were observed compared to WLTC: excluding one vehicle, when switching from gasoline to LPG/DME fueling, the overall emission profiles reflected those of the same vehicles run on the WLTC. The unregulated particulate emissions measured over both testing cycles reflect what was detected for the regulated ones. Except for PN10, which was not measured, all regulated emissions were found to meet the (most severe) Euro 7 standards proposed at first by the European Commission. RDE tests showed that all vehicle emissions obtained from on-road tests were also found to meet the RDE standards, regardless of the fueling. Concerning CO2 emissions, LPG/DME fueling guaranteed a systematic decrease for all vehicles and cycles, both on road and in the laboratory. The present investigation aims at demonstrating that the innovative LPG/DME 80 %/20 % (m/m) blend not only can be deemed as potentially suitable for GHG emissions reduction, as long as both DME and propane are obtained from renewable sources, but even compliant with EN 589 and both Euro 6 and part of preliminary Euro 7 exhaust emission proposal.

Self-sustained carbonization of oil palm biomass produced an acceptable heating value charcoal with low gaseous emission

Abstract Charcoal production with higher heating value (HHV) requires high capital investment and high energy requirement for large scale production. In this study, charcoal production under self-sustained carbonization from oil palm biomass was proposed and tested at pilot scale, whereby temperature and exhaust gas flow rate were monitored but not controlled. This proposed system under self-sustained carbonization, whereby oil palm biomass is combusted to provide the heat for carbonization in inadequate oxygen is preferable to the industry due to its simplicity, ease of operation and low energy requirement. Moreover, the gaseous emissions are below the permitted level set by the environmental authorities. The considerable HHV obtained was between 23 and 25 MJ/kg with low gaseous emissions. The results obtained are acceptable and comparable to other studies on oil palm biomass conducted under controlled conditions with electrical heating elements.

Behavior of Heavy Metals during Fluidized Bed Combustion of Poultry Litter

In this study, we have examined the behavior of heavy metals during fluidized bed combustion of poultry litter. Heavy metals examined include As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V, and Zn. Solid and gaseous streams were analyzed and compared with relevant guidelines to determine the potential environmental impact of combustion and subsequent land spreading or landfill of the resulting ash. The majority of heavy metals were associated with the solid ash fraction, with low gaseous emissions. Pb and As were concentrated in the fine baghouse ash (160 °C) due to their volatility. The remaining heavy metals, excluding Cd, were enriched in the heat exchangers and cyclone, where flue gas temperatures ranged from 580 to 220 °C. Under the waste acceptance criteria, all samples of process ash, excluding bed ash, exceeded the limits for nonhazardous landfill waste, as a result of high levels of water-soluble Cr. Water-soluble Cr indicated the presence of Cr(VI), and its presence was confirmed using X-ray absorpti...

Environmental assessment of two home composts with high and low gaseous emissions of the composting process

A Life Cycle Assessment (LCA) of two home composts with low and high gaseous emissions of the composting process is presented. The study focused on the gaseous emissions of the composting process. Gaseous emissions of methane, nitrous oxides, ammonia and volatic organic compounds of the composting process were experimentally measured in field real trials. The results showed that the differences in gaseous emissions between the two home composts were 4.5, 5.8 and 52 for methane, nitrous oxides and ammonia, respectively. Higher emissions of nitrous oxides and methane affected significantly the category of global warming potential, while higher emissions of ammonia affected mainly the categories of acidification potential, eutrophication potential and photochemical oxidation. The differences found in the compost emissions were attributable to the composting production management (quality and composition of waste stream, frequency mixing of waste, humidity and temperature monitoring, among others) as well as weather conditions (temperature and humidity).

A high efficiency 10 kWe microcogenerator based on an Atkinson cycle internal combustion engine

The paper focuses on the design and the overall performance of a 10 kW electric power microcogeneration plant suitable for local energy production, based on an Atkinson-cycle internal combustion engine prototype and entirely set by Istituto Motori of the Italian National Research Council. The engine was originally a wide-spread Diesel automotive unit, then converted into a methane spark ignition system and finally modified to perform an Atkinson/Miller cycle with an extended expansion, capable of a higher global efficiency and low gaseous emissions. The paper starts by defining the ratio which leaded to this specific choice among many other automotive and industrial engines, in order to obtain a reliable, long endurance, cost effective, high efficiency base, suitable for microcogeneration in residential or commercial applications. The new engine has been coupled with a liquid cooled induction generator, a set of heat exchangers and finally placed in a sealed containing case, to reduce both noise emission and heat losses. Then the plant has been tested as an electricity and heat production system, ready for grid connection thanks to a new designed management/control system. During endurance test a complete description of its functioning behaviour has been given.

Experimental investigation on the combustion and heat transfer characteristics of wide size biomass co-firing in 0.2 MW circulating fluidized bed

In order to reduce emissions and enhance combustion efficiency and bed-to-wall heat transfer in circulating fluidized bed (CFB), wide size crushed biomass pellets were adopted for co-firing. The influences of biomass share on bed pressure, temperature profiles, fly ash loss, heat transfer, and gaseous pollutant emissions were studied by experiments performed in a 0.2 MW pilot scale CFB. Results show that with higher biomass share, more uniform axis temperature profiles, lower fly ash loss, less gaseous emission and higher bed-to-wall heat transfer can be achieved, but the effect of biomass share on bed pressure and porosity is minor. As biomass share increases, the reducing atmosphere formed at the upper part of the dense zone is enhanced, and the temperature at the lower part is decreased. This inhibits the formation of NO, N2O and SO2 in the dense zone, while promotes their reduction, so lower gaseous emissions are obtained. Biomass char with small diameter that generated in the dense zone can be consumed soon after the introduction of secondary air, which achieves lower fly ash loss. The fine particles yielded from biomass combustion reduce the thickness of the heat-conduction gas layer between clusters and water wall, and the heat transfer coefficient can be improved by 10%.

Thermal Treatment of Landfill Leachate and the Emission Control

The main aim of this study was to develop an appropriate system for the thermal treatment of landfill leachate. In the initial phase of this study, characterization studies were conducted both for the waste disposed and leachate generated. For the thermal treatment of the landfill leachate two different incineration systems, namely a double-phase liquid waste incineration system and a new pilot-scale incineration system, were tested. During the experimental study, the capability of the new pilot-scale incineration system was proven to treat the landfill leachate. However, high concentrations of NOx were recorded. On the other hand, the experimental data, obtained during the testing period of the double-phase liquid waste incineration system, indicated that the fluidized bed incinerator provided an extra unit sufficient to complete the oxidation of partial products of combustion and organics carried from the initial incinerator. Therefore, lower gaseous emissions were noted. However, an agglomeration problem has occurred, due to the high concentrations of Na, Ca and K. It was concluded that considering the flexibility of the thermal processes, thermal treatment of leachate could successfully be applied to Odayeri landfill, as well as to many landfills, if proper gas treatment systems are applied.

Treatability of Alexandria Wastewater Using Pure Oxygen Activated Sludge Process

Treatability of Alexandria wastewater using pure oxygen activated sludge process Mahmoud F. El-Sharkawy Mekawy M. Akel Linda M. Saad Ghazy S. Abdel-Kerim Mohamed H. Ramadan Moetaz M. El-Sergany Environmental Health Dept., High Institute of Public Health, Alexandria University Publisher: Presented in the fifth International Conference Role of Engineering in Improving the Environment, 11-13 December 2004, Alexandria University, Alexandria Abstract: Alexandria is the second largest city and main port of Egypt. It lies north west of the Nile Delta. Most of the collected sewage from the city is pumped to two wastewater treatment plants. Both plants are using primary treatment technology and discharge their primary treated effluents into lake Maryut. Therefore the discharges of these plants have resulted in more deterioration of the lake. In Alexandria, the population growth had also led to an increase in land cost due to rarity of land and expansion of residential areas. Accordingly, a suitable wastewater treatment technique characterized by less land requirement, less sludge production, high efficiency, and lower gaseous emissions should be considered. This study was carried out to investigate the treatability and feasibility of applying pure oxygen activated sludge process compared to air activated sludge process. Two pilot scale activated sludge units with internal solids circulation were used. One of these units was operated with compressed air and the second was operated with pure oxygen gas. The units were fed with the primary settled effluent of the East Treatment Plant. Both units were operated at different sludge ages and detention times. At each condition, both units were evaluated. The results showed that a satisfactory effluent quality could be achieved at sludge age of 6 days and detention time ranging from 5.5 to 9 hours, and at sludge age of 6 days and detention time ranging from 2 to 3 hours for air and pure oxygen activated sludge units, respectively. The pure oxygen system produced better effluent quality at higher Food/Microorganism (F/M) ratio than that of the air unit. Pure oxygen can produce a good settling activated sludge compared with the air activated sludge system. Lower sludge quantities could be obtained for the pure oxygen system compared to the air system operated at the same sludge age. Nitrification occurred in both systems during all the applied operating conditions. The feasibility study showed that pure oxygen system is better than air system in both plants in saving the cost of land required to achieve secondary treatment, and in the cost of sludge thickening. Finally, the study ended by some recommendations which are suitable for Alexandria city.