Influences of exhaust gas temperature and flow rate on optimal catalyst activity profiles

Author(s):  
Young-Deuk Kim ◽  
Woo-Seung Kim ◽  
Youngjin Lee
2022 ◽  
pp. 146808742110722
Author(s):  
Jie Shi ◽  
Yuanqing Zhu ◽  
Hui Peng ◽  
Haoyu Yan ◽  
Tinghui Li ◽  
...  

With the increasing awareness of global marine environmental protection, the emission of ship exhaust pollutants is strictly restricted. Selective catalytic reduction (SCR) technology is the mainstream technology to reduce ship NOx emission and make it meet IMO tier III regulations. A SCR reaction kinetic model based on Modelica language was established by Dymola software to predict the denitration efficiency, ammonia slip rate, and other parameters of SCR system. According to the functional structure of marine SCR system, the SCR system model is divided into urea injection module, mixer module, and SCR reactor module. The model was verified by SCR system bench test of WD10 diesel engine, which proved that the model can preferably reflect the actual situation. Using the established model, the effects of temperature, flow rate, NH3/NOx Stoichiometric Ratio (NSR), and cell density on the denitration performance of SCR system were analyzed. The results showed that the exhaust gas temperature and NSR have a great influence on the denitration efficiency. The injection amount of urea solution in marine SCR system should be based on the exhaust gas temperature and exhaust flow rate.


2017 ◽  
Vol 17 ◽  
pp. 179-193
Author(s):  
M. Feroskhan ◽  
Ismail Saleel

Biogas is a promising alternative fuel for compression ignition (CI) engines owing to its renewability and carbon neutrality. In this study, biogas was used along with diesel in a CI engine in dual fuel mode, i.e. biogas is inducted along with air and this mixture is ignited by the in-cylinder injection of diesel. The viability of using cerium oxide (CeO2) nanoparticles as an additive to diesel was also explored. The effects of three parameters, viz. biogas flow rate and concentration of CeO2 nanoparticles and applied load on engine performance were investigated under constant speed operation. These parameters were varied in the ranges of 0 - 12 litre/min, 0 - 35 mg/litre and 5 - 22 N.m respectively. The experimental test matrix was reduced to 16 trials using Taguchi’s approach. Performance was quantified in terms of brake thermal efficiency, volumetric efficiency, diesel consumption, exhaust gas temperature and overall equivalence ratio. The criteria for optimum performance were defined as maximum brake thermal and volumetric efficiencies and minimum diesel consumption, exhaust gas temperature and overall equivalence ratio. Optimum operating conditions were identified by evaluating the signal to noise ratio (SNR) for each performance parameter and using the higher-the-better (HTB) or lower-the-better (LTB) condition as applicable. Contributions of individual parameters towards the performance indices were found using ANOVA. Load was found to be the main contributing factor for brake thermal efficiency, exhaust gas temperature and overall equivalence ratio. Biogas flow rate showed significant contribution towards volumetric efficiency. Biogas flow rate and load had comparable influences on diesel consumption. Addition of nanoparticles showed minor contribution towards all the performance parameters.


Author(s):  
Mostafa Raafat Kotob ◽  
Tianfeng Lu ◽  
Seddik S. Wahid

Direct Water Injection (DWI) is commonly used in many nitrogen oxides (NOx) emissions control applications due to its effect to reduce the adiabatic flame temperature. In this paper an experimental test rig is designed to study the effect of water injection spray inside a simulated gas turbine combustor from the gas fuel. The practical work introduced by the chemical reaction methodology followed by the experiment which was presented and discussed carefully. Results are obtained in term of the exhaust gas temperature and different injection parameters including position, direction and fuel mass flow rate on the nitrogen oxide emission value in PPM (Parts per Million) at different conditions. The results showed that the best water injection effect was obtained at 45° degree inside the primary air zone. Injection location has a major effect on the NOx reduction as the best injected location is the Primary air zone compared with the direct fuel nozzle tip due to the increase of the water droplets residence time inside the combustor and perform a vortex that will affect the reduction of exhaust gas temperature and NOx emission respectively. The huge impact was observed at LPG (Liquefied Petroleum gas) flowrate 2.7L/min and water to fuel ratio about 0.4 as the NOx value was decreased about 73% from almost 381 PPM to 73 PPM. The chemical reaction arrangement order methodology presented good agreement with the experimental results at different fuel flow rate and equivalence ratio. The chemical Reaction equations were implemented to calculate the different adiabatic flame temperatures which is experimentally known as the exhaust gas temperature and impacted directly the NOx emission results.


2020 ◽  
pp. 431-434
Author(s):  
Oliver Arndt

This paper deals with the conversion of coke fired lime kilns to gas and the conclusions drawn from the completed projects. The paper presents (1) the decision process associated with the adoption of the new technology, (2) the necessary steps of the conversion, (3) the experiences and issues which occurred during the first campaign, (4) the impacts on the beet sugar factory (i.e. on the CO2 balance and exhaust gas temperature), (5) the long term impressions and capabilities of several campaigns of operation, (6) the details of available technologies and (7) additional benefits that would justify a conversion from coke to natural gas operation on existing lime kilns. (8) Forecast view to develop systems usable for alternative gaseous fuels (e.g. biogas).


2015 ◽  
Vol 22 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Zbigniew Korczewski

Abstract The article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard online measurements of the exhaust gas temperature. A proposal is made to extend the parametric methods of diagnosing workspaces in turbocharged marine engines by analysing time-histories of enthalpy changes of the exhaust gas flowing to the turbocompressor turbine. Such a time-history can be worked out based on dynamic measurements of the exhaust gas temperature, performed using a specially designed sheathed thermocouple. The first part of the article discusses possibilities to perform diagnostic inference about technical condition of a marine engine with pulse turbocharging system based on standard measurements of exhaust gas temperature in characteristic control cross-sections of its thermal and flow system. Selected metrological issues of online exhaust gas temperature measurements in those engines are discusses in detail, with special attention being focused on the observed disturbances and thermodynamic interpretation of the recorded measuring signal. Diagnostic informativeness of the exhaust gas temperature measurements performed in steady-state conditions of engine operation is analysed in the context of possible evaluations of technical condition of the engine workspaces, the injection system, and the fuel delivery process.


2012 ◽  
Vol 622-623 ◽  
pp. 1162-1167
Author(s):  
Han Fei Tuo

In this study, energetic based fluid selection for a solid oxide fuel cell-organic rankine combined power system is investigated. 9 dry organic fluids with varied critical temperatures are chosen and their corresponding ORC cycle performances are evaluated at different turbine inlet temperatures and exhaust gas temperature (waste heat source) from the upper cycle. It is found that actual ORC cycle efficiency for each fluid strongly depends on the waste heat recovery performance of the heat recovery vapor generator. Exhaust gas temperature determines the optimal fluid which yields the highest efficiency.


Author(s):  
S. Mohammad Javadi ◽  
Pourya Nikoueeyan ◽  
Mohammad Moghiman ◽  
M. Ebrahim Feyz

The enhancement of the flame radiation in gas fueled burners not only improves the thermal efficiency, but also can suppress the rate of NO emission due to reducing the flame temperature. In this experimental investigation, the effect of inlet gas temperature on the flame radiation intensity and the rate of NO formation are studied. To serve this aim, with increasing the temperature of inlet methane to the burner up to 310°C, the variations of CO and NO level in exhaust gases and also the exhaust gas temperature are recorded by gas analyzer device. In each case, the flame radiation intensity was also measured by a photovoltaic module. The results revealed that by increasing the inlet gas temperature up to 250°C, the NO concentration and the exhaust gases temperature are raising. But when the inlet gas temperature exceeds from 250°C and reaches to 310°C, the flame luminosity gradually increases which results in 70 percent growth in flame radiation and 10 percent drop in exhaust gas temperature. The results of the preheating of inlet air also show the same behavior.


Author(s):  
Mehrzad Kaiadi ◽  
Per Tunestal ◽  
Bengt Johansson

High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition Natural Gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Most of the heavy duty NG engines are diesel engines which are converted for SI operation. These engine’s components are in common with the diesel-engine which put limits on higher exhaust gas temperature. The engines have lower maximum load level than the corresponding diesel engines. This is mainly due to the lower density of NG, lower compression ratio and limits on knocking and also high exhaust gas temperature. They also have lower efficiency due to mainly the lower compression ratio and the throttling losses. However performing some modifications on the engines such as redesigning the engine’s piston in a way to achieve higher compression ratio and more turbulence, modifying EGR system and optimizing the turbocharging system will result in improving the overall efficiency and the maximum load limit of the engine. This paper presents the detailed information about the engine modifications which result in improving the overall efficiency and extending the maximum load of the engine. Control-related problems associated with the higher loads are also identified and appropriate solutions are suggested.


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