Eddy Covariance Measurements Highlight Sources of Nitrogen Oxide Emissions Missing from Inventories for Central London

During March–June 2017 emissions of nitrogen oxides were measured via eddy covariance at the British Telecom Tower in central London, UK. Through the use of a footprint model the expected emissions were simulated from the spatially resolved National Atmospheric Emissions Inventory for 2017, and compared with the measured emissions. These simulated emissions were shown to underestimate measured emissions during the day time by a factor of 1.48, but they agreed well overnight. Furthermore, underestimations were spatially mapped and the areas around the measurement site responsible for differences in measured and simulated emissions inferred. It was observed that areas of higher traffic, such as major roads near national rail stations, showed the greatest underestimation by the simulated emissions. These discrepancies are partially attributed to a combination of the inventory not fully capturing traffic conditions in central London, and both spatial and temporal resolution of the inventory not fully describing the high heterogeneity of the urban centre. Understanding of this underestimation may further improved with longer measurement time series ,to better understand temporal variation, and improved temporal scaling factors, to better simulate sub-annual emissions.

Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

Investigation of the characteristics of a marine diesel engine when running on fuel with a water additive

Currently, environmental specifications of marine diesel engines become more stringent. There are two well-known and popular ways to improve engine environmental performance: the internal method is based on operation process improvement, as well as on the use of various fuel additives or air supply to the diesel cylinder. Another method is external (gas purification using catalysts and filters). The article considers one of these possible ways of reducing nitrogen oxides in marine diesel engines by using a water agent in fuel with various water phase dispersion degrees. The high-speed characteristics of the ship engine operation under various modes using “L” brand diesel fuel and emulsions are given. Studies have shown that when converting diesel from pure fuel to a microheterogenous emulsion (water inclusions’ diameter 5-10 microns), the concentration of NOx decreased by 1.4 times, fuel consumption increased by (4-5) g/(kWh), with an increase in the maximum combustion pressure by 0.7 MPa. The tests have confirmed the effectiveness of using a microheterogenous emulsion to reduce nitrogen oxide emissions.

Analysis of Combustion Characteristics and Emission Characteristics of Alternative Fuels Worldwide

The combustion characteristics and emission characteristics of the commonly used alternative fuels in the fuel process are reviewed, the three types of alternative fuels are: Alcohols alternative fuel, biological alternative fuel and gas alternative fuel. The three alternative fuels have their own advantages and disadvantages in combustion characteristics and emission characteristics. The dual fuel blended with alcohols has a higher burning rate than pure diesel or gasoline, and emits fewer soot particles. When biofuel is blended into traditional fuel, the thermal efficiency is improved, and the particle diameter of the emitted particles is smaller than that of pure diesel. The use of hydrogen fuel increases the power of the engine, and significantly reduces the content of CO and CO2 in the emissions. With the increase of the proportion of hydrogen, the amount of soot emitted becomes less, but the amount of nitrogen oxide emissions increases. Each of the three types of alternative fuels has its own characteristics and advantages.

Performance, Combustion and Emission Characteristics of a Common Rail Direct Injection Diesel Engine Fueled by Diesel/n-Amyl Alcohol Blends with Exhaust Gas Recirculation Technique

Biofuels are considered as one of the best viable and inexhaustible alternatives to conventional diesel fuel. Alcohols have become very important and popular in the present scenario due to their peculiar fuel properties and production nature. This study examines the effect of n-amyl alcohol and exhaust gas recirculation of 10% and 20% on various engine characteristics of Common Rail Direct Injection (CRDI) compression ignition engine. The proportion of n-amyl alcohol varies from 5% to 25% in 5% step (by volume). The obtained results show that diesel/n-amyl alcohol blends decrease the mean gas temperature and cylinder pressure, which is 1.88% and 4.25% less at 75% load for n-amyl alcohol (25%) with conventional diesel fuel. The duration of combustion has shown a hike of 4.66°CA for 25% n-amyl alcohol (at 75% load) compared to conventional diesel fuel. However, the cumulative heat release rate improved by 12.95% higher for 25% n-amyl alcohol at 75% load, the reason for the same is due to the extended delay in ignition. While n-amyl alcohol was used, the emission of nitrogen oxide emissions decreased considerably. However, the hydrocarbon (HC) (7-9%) and carbon monoxide (CO) (6-8%) emissions are increased due to inferior fuel properties like high latent heat evaporation of n-amyl alcohol. Compared with other blends, n-amyl alcohol (5%) produced results comparable to conventional diesel fuel, which is 3.6% higher in BSFC, 2.37 % higher BTE, and 33.33% higher CO emissions 18.18% more in HC emission, and 17.55% less NOx emission. Without further modification, we can use 25% n-amyl alcohol in the combustion ignition engines. From this evidence, we can summarize that n-amyl alcohol is a biofuel that is both renewable and sustainable, and also it considerably reduces harmful nitrogen oxide emissions. The performance, if needed, can be improved by changing the parameters of the engine.

Determining basic characteristics of stabilizer micro torch burners for the combustion of ballasted fuel gases

This paper reports an experimental study into the combustion of alternative gases in the form of a mixture of propane-butane with air and carbon dioxide after a stabilizing flat module whose both sides are flown around with an airflow. The ballasted fuel was fed by jets into the airflow from the holes located on the side walls of the stabilizer. In this case, the fuel and air were partially premixed. It was established that when ballasting fuel with inert admixtures, the length of the torch and the maximum temperature gradually decreased while nitrogen oxide emissions decreased. With an increase in the content of ballast in fuel, combustion breaks. The dependence of torch stability on the relative consumption of ballast has been established. To stabilize the combustion, highly reactive fuel is supplied to the recirculation zone after a stabilizer from a separate collector. Ballasted fuel passes through the next torches of high-temperature fuel; the all fuel combustion process takes place. The combined scheme of mixture formation makes it possible to adjust fuel consumption in the zones and thus maintain a stable burner power. In the case of supplying all fuel to the recirculation zone after the stabilizer, a so-called "rich" detachment is possible when the torch is detached from the stabilizer. When working under such modes, highly reactive fuel is supplied from the holes on the side walls of the stabilizer, which are placed closer to its detachment edges than the holes for the supply of ballasted fuel. At the same time, the jets of ballasted fuel also pass between the torches of highly reactive fuel so there is joint combustion of all fuel

Improvement of Working Conditions of Mining Workers by Reducing Nitrogen Oxide Emissions during Blasting Operations

The article presents comparison of the values of maximum permissible concentrations, revealed during the analysis of the national standards of Russia and Australia in the field of regulation of nitrogen oxides. The impact of poisoning of the workers of the quarry with nitrogen oxides after blasting operations are presented. A detailed review of studies of methods for reducing nitrogen oxide emissions is given. The way of decreasing emission of nitrogen oxides using highly active catalysts as a part of the profiled tamping is offered. Laboratory studies were carried out using a model explosive and pentaerythritol tetranitrate. The results obtained showed that zinc carbonate (ZnCO3) is the most effective. The reduction in the amount of nitrogen oxide emissions was 40% of that released during experiments without the addition of catalysts.

Quantifying aviation’s contribution to global warming

Growth in aviation contributes more to global warming than is generally appreciated because of the mix of climate pollutants it generates. Here, we model the CO2 and non-CO2 effects like nitrogen oxide emissions and contrail formation to analyse aviation’s total warming footprint. Aviation contributed approximately 4% to observed human-induced global warming to date, despite being responsible for only 2.4% of global annual emissions of CO2. Aviation is projected to cause a total of about 0.1 °C of warming by 2050, half of it to date and the other half over the next three decades, should aviation’s pre-COVID growth resume. The industry would then contribute a 6%–17% share to the remaining 0.3 °C–0.8 °C to not exceed 1.5 °C–2 °C of global warming. Under this scenario, the reduction due to COVID-19 to date is small and is projected to only delay aviation’s warming contribution by about five years. But the leveraging impact of growth also represents an opportunity: aviation’s contribution to further warming would be immediately halted by either a sustained annual 2.5% decrease in air traffic under the existing fuel mix, or a transition to a 90% carbon-neutral fuel mix by 2050.