Reduction of NOx Emission From Diesel Engines Using Cu-ZSM-5 Catalyst

Author(s):  
Yoshiyuki Aoyagi ◽  
Masahiro Kaneda ◽  
Keisuke Numahata ◽  
Koji Korematsu ◽  
Junya Tanaka

Abstract In this paper effect of on reduction a Cu-ZSM-5 catalyst of nitrogen oxides is investigated in a diesel engine. This research focuses to solve a problem that there is not enough THC to reduce nitrogen oxides in exhaust gas from a diesel engine. When diesel oil is directly supplied into the exhaust gas, the THC concentration sharply rises and the NOx conversion rate increases. The maximum NOx conversion rate reaches to 63% when the flow rate of diesel oil is 30 ml/min at a catalyst temperature 450 °C. The NOx reduction with less sacrifice of the specific fuel consumption is possible when the fuel is supplied into the exhaust pipe.

2020 ◽  
Vol 19 (4) ◽  
pp. 305-310
Author(s):  
G. M. Kuharonak ◽  
D. V. Kapskiy ◽  
V. I. Berezun

The purpose of this work is to consider the requirements for emissions of harmful substances of diesel engines by selecting design and adjustment parameters that determine the organization of the workflow, and the exhaust gas cleaning system, taking into account the reduction of fuel consumption. Design elements and geometric characteristics of structures for a turbocharged diesel engine of Д-245 series produced by JSC HMC Minsk Motor Plant (4ЧН11/12.5) with a capacity of 90 kW equipped with an electronically controlled battery fuel injection have been developed: exhaust gas recirculation along the high pressure circuit, shape and dimensions of the combustion chamber, the number and angular arrangement of the nozzle openings in a nozzle atomizer, and inlet channels of the cylinder head. Methods for organizing a workflow are proposed that take into account the shape of the indicator diagrams and affect the emissions of nitrogen oxides and dispersed particles differently. Their implementation allows us to determine the boundary ranges of changes in the control parameters of the fuel supply and exhaust gas recirculation systems when determining the area of minimizing the specific effective fuel consumption and the range of studies for the environmental performance of a diesel engine. The paper presents results of the study on the ways to meet  the requirements for emissions of harmful substances, obtained by considering options for the organization of working processes, taking into account the reduction in specific effective fuel consumption, changes in the average temperature of the exhaust gases and diesel equipment. To evaluate these methods, the following indicators have been identified: changes in specific fuel consumption and average temperature of the toxicity cycle relative to the base cycle, the necessary degree of conversion of the purification system for dispersed particles and NOx. Recommendations are given on choosing a diesel engine to meet Stage 4 emission standards for nitrogen oxides and dispersed particles.


Author(s):  
Giancarlo Chiatti ◽  
Ornella Chiavola

A comparative series of experimental tests has been performed on a 4-stroke multi cylinder indirect injection diesel engine fueled with diesel oil, pure gas-turbine fuel and gas-turbine fuel with additives. The engine has been equipped aimed at monitoring both the overall performances and the variation with time of the pressure in the pre-combustion chamber. Some key parameters have been investigated at different engine speeds and loads (ignition delay, pressure rise in the pre-combustion chamber, power output, specific fuel consumption, exhaust gas temperature) and discussed results are presented.


Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 452 ◽  
Author(s):  
Feng Qian ◽  
Dong Ma ◽  
Neng Zhu ◽  
Peng Li ◽  
Xiaowei Xu

For the National VI heavy-duty diesel vehicles, NOx emission regulations are becoming more and more stringent, and the selective catalytic reduction (SCR) system has become a necessary device. The design of the adblue nozzle in the SCR system is especially critical, directly affecting the NOx conversion efficiency and deposit formation. According to the structure of a National VI diesel engine exhaust pipe and SCR system, the nozzle is optimized by computational fluid dynamics (CFD) method to avoid the collision between the urea droplets and the exhaust pipe wall, to ensure that the exhaust gas and the urea droplets are as much as possible in full contact to ensure a sufficient urea pyrolysis. With the optimized nozzle, the NH3 distribution uniformity of the inlet face of the SCR catalyst can increase from 0.58 to 0.92. Additionally, test verifications are implemented based on the spray particle size test and the engine bench tests; the results show that the Sauter mean diameter of the optimized nozzle is more decreased than the initial nozzle and that the NOx conversion efficiency of the World Harmonized Transient Cycle (WHTC) and World Harmonized Stationary Cycle (WHSC) cycle improves by nearly 3%; additionally, it can also avoid deposit formation.


1997 ◽  
Vol 2 (2) ◽  
Author(s):  
Katsuharu Kinoshita ◽  
Shigeo Watanabe, ◽  
Niichi Hayash ◽  
Yoshiyuki Uchida ◽  
David Dykes ◽  
...  

AbstractDiesel engine exhaust gas is known to be one cause of photochemical smog, which is so damaging to city environments. However, because of its high thermal efficiency and economic advantages, the diesel engine is not easily dispensable. The authors have previously conducted a series of experiments to assess the purifying effects of a diesel gas purification device employing an electric trap. It has been confirmed that an extraction rate of 60∼75 % for black smoke can be achieved using this apparatus. But the extraction effect for nitrogen oxides (NOx) is insufficient if the electro-trap device is used on its own. To improve its performance, experiments have now been undertaken using the same device in combination with various types of attached catalysers to oxidise and remove the nitrogen in the exhaust gas. Utilising a commercial 3-way catalyser, it proved difficult to maintain the gas at a suitable temperature, so that no outstanding result could be obtained. Nor was any significant result observ­ed from the use of an ozoniser. However, with a zeolyte catalyser, it was possible to achieve a NOx reduction of 20∼30 %. This latter experiment is reported in the present paper.


Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1155
Author(s):  
Keqin Zhao ◽  
Diming Lou ◽  
Yunhua Zhang ◽  
Liang Fang ◽  
Yuanzhi Tang

The thermal insulation performance of exhaust pipes coated with various materials (basalt and glass fiber materials) under different braiding forms (sleeve, winding and felt types) and the effects on the emission characteristics of diesel engines were experimentally studied through engine bench tests. The results indicated that the thermal insulation performance of basalt fiber was higher than that of glass fiber, and more notably advantageous at the early stage of the diesel engine idle cold phase. The average temperature drop during the first 600 s of the basalt felt (BF) pipe was 2.6 °C smaller than that of the glass fiber felt (GF) pipe. Comparing the different braiding forms, the temperature decrease in the felt-type braided material was 2.6 °C and 2.9 °C smaller than that in the sleeve- and winding-type braided materials, respectively. The basalt material was better than the glass fiber material regarding the gaseous pollutant emission reduction performance, especially in the idling cold phase of diesel engines. The NOx conversion rate of the BF pipe was 7.4% higher than that of the GF pipe, and the hydrocarbon (HC) conversion rate was 2.3% higher than that of the GF pipe, while the CO conversion rate during the first 100 s was 24.5% higher than that of the GF pipe. However, the particulate matter emissions were not notably different.


1979 ◽  
Author(s):  
Y. Hishinuma ◽  
F. Nakajima ◽  
H. Akimoto ◽  
Y. Uchiyama ◽  
S. Azuhata ◽  
...  

For the removal of NOx in a gas turbine exhaust gas, the reduction of NOx with NH3 and H2O2 was studied. It was found that the addition of H2O2 very effectively lowers the reduction temperature of NO with NH3 and that more than 90 percent NOx reduction could be attained at 550 C in the absence of O2. However, the NOx reduction rate decreased with increases in the concentration of O2, and NOx reduction was about 40 to 60 percent under gas turbine exhaust gas condition (15 percent O2). In order to attain a high rate of reduction of NOx, a combined reduction process, which consisted of homogeneous gas phase and the catalytic heterogeneous reactions, was also developed. The efficiency of the new process was proved in a pilot plant using half a size model of a 25-MW gas turbine combustor.


Author(s):  
Carlo Beatrice ◽  
Giovanni Avolio ◽  
Nicola Del Giacomo ◽  
Chiara Guido

The present paper describes the effects of some air-path operating parameters on the performance of a modern common-rail diesel engine when it runs under Low Temperature Combustion (LTC) conditions. Aim of the experimental work was to explore the potential of the control of each parameter on the improvement of LTC application to the modern LD diesel engines for passenger cars, in order to meet future NOx emissions limits avoiding penalties in fuel consumption and drivability. In particular, the effects on LTC performance of the following operating parameters were analysed: intake air temperature, exhaust EGR cooler temperature, intake pipe pressure, exhaust pipe pressure and swirl ratio. Tests are carried out with a single-cylinder research diesel engine derived from FIAT 1.9 JTD 16V Multi-Jet in the EURO4 version. Results analysis have shown a significant influence of some examined parameters on the improvement of EGR tolerability, that has led to sensitive NOx reduction, within fixed limits in fuel consumption and smoke. On the contrary, engine behaviour is insensitive to the variation of the other air-path parameters.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Lijiang Wei ◽  
Anmin Wu ◽  
Jie Liu ◽  
Mingliang Zhong ◽  
Xuebai Wang

For the two-stroke marine diesel engine, the action of exhaust valve has a significant impact on scavenging and combustion processes and ultimately affects the engine performances and emissions. In order to reduce nitrogen oxides (NOx) emissions of a two-stroke marine diesel engine, different exhaust valve lifts (EVLs) were achieved by computational fluid dynamics simulation method in this study. The NOx reduction effect and influence mechanism of EVL on a two-stroke marine diesel engine were investigated in detail. The results showed that the in-cylinder residual exhaust gas and the internal exhaust gas recirculation (EGR) rate gradually increased with the decreasing EVL. Although the total mass of charge enclosed in the cylinder did not change much, the composition changed gradually and the maximum internal EGR rate reached 13.17% in this study. The maximum compression pressure and combustion pressure both rose first and then decreased with the decreasing EVL. While the start of combustion and the maximum combustion temperature were basically unaffected by EVL, the indicated power of the engine was also not much impacted when the EVL was changed from increasing 10 mm to decreasing 20 mm. The indicated specific fuel consumption first declined slowly and then rose rapidly as the EVL reduction exceeded 20 mm. NOx emissions decreased monotonously with the decreasing EVL. The reduction of NOx formation rate and the amount of NOx formation mass mainly occurred at the middle and late stages of combustion for the downward moving of residual exhaust gas. NOx emissions were reduced by 12.57% without compromising other engine performances at medium-reduced EVL in this study. However, in order to further reduce NOx emissions at low EVLs, other measures may be needed to make the residual exhaust gas more evenly distributed during the initial stage of combustion.


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