scholarly journals Producing Effective and Clean Coke for Household Combustion Activities to Reduce Gaseous Pollutant Emissions

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Shoujun Liu ◽  
Ju Shangguan ◽  
Song Yang ◽  
Wenguang Du ◽  
Xudong Yan ◽  
...  
Keyword(s):  
High Temperature ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Atmospheric Environment ◽  
Gaseous Pollutant ◽  
New Type ◽  
Coke Combustion ◽  
Household Activities ◽  
Sulfur And Nitrogen Compounds ◽  
Sulfur Fixation

Nowadays, the gaseous pollutant emissions, including particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxide (NOx) from household coal combustion, cause great threat to environment and public health by contributing to severe haze in China. Particularly, a clean coke free of the major pollutants precursors (sulfur and nitrogen compounds) by sulfur fixation and denitrification has been deemed as an effective strategy to reducing pollutants. In this paper, a preprocessed coke was prepared by co-pyrolysis of high-sulfur coal with the assistance of calcium-based and iron-based complexes at high temperature. The results show that high-temperature co-pyrolysis could remove the volatile compounds that are major precursors for the formation of gaseous pollutants from the raw coal. During the coking process, the sulfur can be removed by being fixed in the form of CaS in presence of a Ca-based complex, which could be beneficial for the CaSO4 during the coke combustion. The volatile nitrogen is transferred to the gas phase with the addition of Fe-based complexes, which effectively reduce the residual nitrogen in coke. As a result, Ca-based additives captured the released SO2 and formed CaSO4 during the combustion process. In addition, in the presence of Fe-based complexes, both char and CO react with NOx to form N2, which leads to a reduction in NOx emissions during combustion. Additionally, the replacement of current residential coal with a new type of clean coke is a facile method for reducing gaseous pollutant emissions from household activities to protect the atmospheric environment. The average emission factors (EFs) of PM, SO2, and NOx for the prepared clean coke were small during combustion and were much lower than the EFs of the tested raw coal, semicoke, and briquettes.

Experimental Study on Combustion Characteristics of Three Biomass Components

2014 ◽  
Vol 953-954 ◽  
pp. 309-312
Author(s):  
Gui Qiu Su ◽  
Jian Yang ◽  
Hong Bo Lu
Keyword(s):  
Experimental Study ◽  
Weight Loss ◽  
High Temperature ◽  
Low Temperature ◽  
Combustion Process ◽  
Combustion Characteristics ◽  
Heating Rates ◽  
Biomass Components ◽  
Coke Combustion ◽  
Obvious Weight Loss

Experiments on combustion characteristics of cellulose, xylan and lignin have been done conducted on Pyris1 TGA thermograyimetric analyzer (PE/USA) at different heating rates. The results show that: combustion of cellulose was mainly concentrated in a low temperature range, xylan has two obvious weight loss peaks, while the lignin combustion mainly concentrated in a high temperature coke combustion process.

Study and Design on High Temperature Air Combustion of Hot Blast Stove

2014 ◽  
Vol 496-500 ◽  
pp. 1058-1062
Author(s):  
Fu Ming Zhang ◽  
Zu Rui Hu ◽  
Shu Sen Cheng
Keyword(s):  
High Temperature ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Formation Rate ◽  
Flame Temperature ◽  
Combustion Process ◽  
High Temperature Air Combustion ◽  
Blast Stove ◽  
New Type ◽  
Hot Blast

During Hot Blast Stove (HBS) combustion, NOxforms rapidly when the flame temperature above 1420°C. In order to restrain the amount of NOxformation during combustion of HBS, the formation mechanism of NOxis investigated, and the NOxformation rate and amount in HBS are calculated by means of thermodynamic model. A new type of dome combustion HBS is developed based on high temperature air combustion (HTAC) technology. A comparison on the combustion process and characteristic of conventional HBS and HTAC HBS is performed by application of Computational Fluid Dynamics (CFD) simulation model. Temperature and concentration distribution, flame shape and NOxconcentration distribution of two kinds of stove are calculated. The result shows quite symmetrical HTAC stove temperature distribution. Under the same dome temperature, NOxamount is 80ppm only, reduced by approximate 76% in comparison with conventional stove.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

scholarly journals Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 540
Author(s):  
Yukyung Kim ◽  
Sanghyuck Lee ◽  
Hyeonseok Yoon
Keyword(s):  
Organic Matter ◽  
High Temperature ◽  
Flame Retardant ◽  
Flame Retardants ◽  
Combustion Process ◽  
Polymeric Materials ◽  
Fire Performance ◽  
Gaseous Species ◽  
Advantages And Disadvantages ◽  
Temperature Conditions

Currently, polymers are competing with metals and ceramics to realize various material characteristics, including mechanical and electrical properties. However, most polymers consist of organic matter, making them vulnerable to flames and high-temperature conditions. In addition, the combustion of polymers consisting of different types of organic matter results in various gaseous hazards. Therefore, to minimize the fire damage, there has been a significant demand for developing polymers that are fire resistant or flame retardant. From this viewpoint, it is crucial to design and synthesize thermally stable polymers that are less likely to decompose into combustible gaseous species under high-temperature conditions. Flame retardants can also be introduced to further reinforce the fire performance of polymers. In this review, the combustion process of organic matter, types of flame retardants, and common flammability testing methods are reviewed. Furthermore, the latest research trends in the use of versatile nanofillers to enhance the fire performance of polymeric materials are discussed with an emphasis on their underlying action, advantages, and disadvantages.

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

2021 ◽  
pp. 146808742110050
Author(s):  
Stefania Esposito ◽  
Lutz Diekhoff ◽  
Stefan Pischinger
Keyword(s):  
Gas Exchange ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Operating Parameters ◽  
Gaseous Pollutant ◽  
Fuel Ratio ◽  
No Emissions

With the further tightening of emission regulations and the introduction of real driving emission tests (RDE), the simulative prediction of emissions is becoming increasingly important for the development of future low-emission internal combustion engines. In this context, gas-exchange simulation can be used as a powerful tool for the evaluation of new design concepts. However, the simplified description of the combustion chamber can make the prediction of complex in-cylinder phenomena like emission formation quite challenging. The present work focuses on the prediction of gaseous pollutants from a spark-ignition (SI) direct injection (DI) engine with 1D–0D gas-exchange simulations. The accuracy of the simulative prediction regarding gaseous pollutant emissions is assessed based on the comparison with measurement data obtained with a research single cylinder engine (SCE). Multiple variations of engine operating parameters – for example, load, speed, air-to-fuel ratio, valve timing – are taken into account to verify the predictivity of the simulation toward changing engine operating conditions. Regarding the unburned hydrocarbon (HC) emissions, phenomenological models are used to estimate the contribution of the piston top-land crevice as well as flame wall-quenching and oil-film fuel adsorption-desorption mechanisms. Regarding CO and NO emissions, multiple approaches to describe the burned zone kinetics in combination with a two-zone 0D combustion chamber model are evaluated. In particular, calculations with reduced reaction kinetics are compared with simplified kinetic descriptions. At engine warm operation, the HC models show an accuracy mainly within 20%. The predictions for the NO emissions follow the trend of the measurements with changing engine operating parameters and all modeled results are mainly within ±20%. Regarding CO emissions, the simplified kinetic models are not capable to predict CO at stoichiometric conditions with errors below 30%. With the usage of a reduced kinetic mechanism, a better prediction capability of CO at stoichiometric air-to-fuel ratio could be achieved.

Method to reduce the oil pressure during HPHT diamond synthesis: FEM simulations and experiments

CrystEngComm ◽  
2020 ◽  
Vol 22 (44) ◽  
pp. 7601-7606
Author(s):  
Chunxiao Wang ◽  
Hong-an Ma ◽  
Liangchao Chen ◽  
Xinyuan Miao ◽  
Liang Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Cell Assembly ◽  
Diamond Synthesis ◽  
Fem Simulations ◽  
High Pressure High Temperature ◽  
New Type

Here, a new type of supercharged cell assembly is proposed that can effectively reduce the oil pressure during high-pressure, high-temperature (HPHT) diamond synthesis.

Study of high-pressure air jet controlled compression ignition with compound thermodynamic cycle for combustion and emission formation process

2020 ◽  
pp. 146808742096933
Author(s):  
Xiangyu Meng ◽  
Sicheng Liu ◽  
Jingchen Cui ◽  
Jiangping Tian ◽  
Wuqiang Long ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Formation Process ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
Air Jet ◽  
High Temperature Reaction

A novel method called high-pressure air (HPA) jet controlled compression ignition (JCCI) based on the compound thermodynamic cycle was investigated in this work. The combustion process of premixed mixture can be controlled flexibly by the high-pressure air jet compression, and it characterizes the intensified low-temperature reaction and two-stage high-temperature reaction. The three-dimensional (3D) computational fluid dynamics (CFD) numerical simulation was employed to study the emission formation process and mechanism, and the effects of high-pressure air jet temperature and duration on emissions were also investigated. The simulation results showed that the NOx formation is mainly affected by the first-stage high-temperature reaction due to the higher reaction temperature. Overall, this combustion mode can obtain ultra-low NOx emission. The second-stage high-temperature reaction plays an important role in the CO and THC formation caused by the mixing effect of the high-pressure air and original in-cylinder mixture. The increasing air jet temperature leads to a larger high-temperature in-cylinder region and more fuel in the first-stage reaction, and therefore resulting in higher NOx emission. However, the increasing air jet temperature can significantly reduce the CO and THC emissions. For the air jet duration comparisons, both too short and too long air jet durations could induce higher NOx emission. A higher air jet duration would result in higher CO emission due to the more high-pressure air jet with relatively low temperature.

Research and Development of Self-Lubricating Bearing Materials

2013 ◽  
Vol 651 ◽  
pp. 198-203
Author(s):  
Xiu Ling Wang ◽  
Li Ying Yang ◽  
Shou Ren Wang
Keyword(s):  
High Temperature ◽  
Research And Development ◽  
Metal Matrix ◽  
Future Trend ◽  
Al Alloy ◽  
Temperature Resistance ◽  
The Future ◽  
High Temperature Resistance ◽  
Bearing Materials ◽  
New Type

It is significant and necessary to carry out the research and development of self-lubricating bearing. The current study of metal matrix self-lubricating bearing materials is summarized. A new type of high temperature self-lubricating Ti-Al alloy bearing materials is proposed. It is light, anti-friction, anti-corrosion and high temperature resistance (600 °C). The future trend is introduced in the end of this paper.

Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

2012 ◽  
Author(s):  
Mirko Baratta ◽  
Stefano d’Ambrosio ◽  
Daniela Misul ◽  
Ezio Spessa
Keyword(s):  
Diagnostic Tool ◽  
Combustion Process ◽  
Experimental Tests ◽  
Test Point ◽  
Pollutant Emissions ◽  
Engine Operation ◽  
Pressure Transducers ◽  
Rate Analysis ◽  
Spark Plug ◽  
Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

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