Burning Loss Research Articles

Hydrothermal carbonization of typical components of municipal solid waste for deriving hydrochars and their combustion behavior

In this work, five typical components were employed as representative pseudo-components to indirectly complete previous established simulation system during hydrothermal carbonization (HTC) of municipal solid waste. The fuel characteristics and combustion behavior of HTC-derived hydrochars were evaluated. Results clearly illustrated that the energy ranks of hydrochars were upgraded after HTC. For paper and wood, superior combustion performances of their hydrochars could achieve under suitable conditions. While for food, none positive enrichments on combustion loss rate were observed for hydrochars due to its high solubilization and decomposition under hot compressed water. It was noteworthy that a new weight loss peak was detected for paper and food, suggesting that new compounds were formed. For rubber, the HTC process made the properties of styrene butadiene rubber more close to natural rubber. Therefore, the first peak of hydrochars became significantly intense. While for plastic, only physical changes of polypropylene and polyethylene were observed.

Establishment of the mechanism and fireproof efficiency of wood treated with an impregnating solution and coatings

Description of the behavior of fireproof means and coatings, including those swelling, in the moment of the formation of a thermal insulating structure is a special and complex task. In general, it covers both stages of the process of thermal protection: both heat transfer and subsequent swelling of the coating, which is formed during fire protection. In necessitates studying conditions for the formation of barrier to thermal conductivity and the establishment of a mechanism of fire protection from layer to a layer of coke. Given this, we examined the process of fire protection with work of an impregnating solution and at swelling of a fireproof coating. Data that we obtained revealed that the formation of volatile products under the effect of coating at high temperature occurs with the formation of noncombustible substances. We established experimentally that under the action of heat flow on the fireproof samples, intense release of inert gases occurs, as well as a reduction in the combustible, which leads to the effectiveness of fire protection in reverse order. It was found in the course of conducted tests that the intensity of the formation of noncombustible gases shifts toward elevated temperature with the formation of coked cellular material. Results of determining a swelling capacity of coating for the intumescent system demonstrated that under the influence of high-temperature flow, material combustion and weight loss of the coating is reduced by more than twice due to the formation of high-temperature compounds; in this case, the time to reach a limit temperature grows as well. A coating under the influence of high temperature forms a significant coefficient of swelling, contributes to the formation of a thermal insulating layer of coke, which prevents wood from burning, as well as the passage of high temperature to the material. In general, the efficiency of wood fire protection revealed that the goods belong to the materials that are difficult to combust, which spread the flame over surface slowly and with low smoke-generating capacity. protection means; fire resistance; volatile products; loss of weight; surface treatment; efficiency of protection

Design of porous wall air coupling with air staged furnace for preventing high temperature corrosion and reducing NOx emissions

Air staged technology can remarkably reduce NOx emissions during pulverized coal combustion. However, it also may result in the negative impacts of high temperature corrosion, slagging, and high imperfect combustion loss. The porous wall air coupling with air staged (PW&AS) furnace is designed and manufactured to overcome these problems. The preliminary experimental results show that PW&AS furnace could effect a simultaneous realization of prevention of high temperature corrosion, high combustion efficiency, and low NOx emissions.

Organic solar cells with near 100% efficiency retention after initial burn-in loss and photo-degradation

In this article, we attempt to demonstrate a way of tackling one of the biggest challenges in the path of commercialization of organic solar cells, the initial photo-degradation of the cells known as “burn-in”. The “burn-in” phenomenon is most prominent during the first few hours of device operation under illumination and responsible for losing 25% or more fraction of the initial efficiency. To address this major issue, we have studied photo degradation of inverted organic solar cells with plain Zinc Oxide (ZnO) and Aluminum doped ZnO (AZO) as an electron transport layer over a short time period of 5h during which the degradation is most severe. The study has been done on two different device structures containing both crystalline and amorphous polymers (Poly(3-hexylthiophene-2,5-diyl) and Poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}), respectively). Application of an AZO layer as the electron transport layer resolves the issue of photo-degradation in both cases, regardless of the polymer used in the active layer. AZO layer is found to provide less charge accumulation and better charge extraction at cathode/active layer interface. Mott-Schottky analysis shows modification of cathode interfacial layer work function and enhancement of open-circuit voltage due to the introduction of doped ZnO as electron transport layer. The exaltation persists even after the ageing of the devices. The devices with AZO layer retain their initial efficiency (almost 100%) even after photo-degradation while the device with pristine ZnO layer loses up to 60% of the initial efficiency.

Effect of the parameters of the thermal modification of brown coals on their sorption properties

The effect of carbonization and activation conditions on the adsorptive and mechanical properties of sorbents obtained from brown coal was studied. It was found that the heat treatment of brown coal before carbonization with an increase in the temperature from 230 to 400°C makes it possible to increase the volume of macropores by 30–40%; however, it does not lead to a change in the microporous structure of activated carbon. The porous structure of carbon sorbents depends on the degree of combustion losses and the temperature of activation. A change in the activation temperature of the carbonized intermediate product from 700 to 900°C makes it possible to regulate the sorption properties of the resulting activated carbons.

Multi-objective optimization of p -xylene oxidation process using an improved self-adaptive differential evolution algorithm

Abstract The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid (TPA). The liquid-phase catalytic oxidation of p -xylene (PX) to TPA is regarded as a critical and efficient chemical process in industry [1] . PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simultaneously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization problems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm (SADE) to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm (ISADE). Optimization results indicate that application of ISADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.

Numerical and experimental investigation of improving combustion performance of variable geometry dual-mode combustor

As part of our efforts to find ways and means to further improve the combustion performance of variable geometry dual-mode combustor, flow field characteristics and mechanisms of combustion performance losses, which included compression and combustion losses resulted by heat addition, were investigated in variable geometry dual-mode combustor numerically and experimentally with a Mach number of 3.0, a divergent ratio ranging from 1.3 to 1.8 and a fuel equivalence ratio varying from 0.6 to 1.2. Irreversible entropy increase analysis was extended specifically in this paper to study the mechanism of combustion performance loss for the variable geometry dual-mode combustor. Numerical and experimental results indicated that for a given fuel equivalence ratio, the wall static pressure, total pressure recovery coefficient, combustion efficiency and thrust of the variable geometry dual-mode combustor increased with the decreasing of divergent ratio and there was a maximum thrust performance for the divergent ratio of 1.3 within stability margin. It was therefore strongly believed that the combustion performance of a variable geometry dual-mode combustor could be further improved by decreasing divergent ratio.

The role of chemical structure in indacenodithienothiophene-alt-benzothiadiazole copolymers for high performance organic solar cells with improved photo-stability through minimization of burn-in loss

The organic solar cell initial burn-in loss is suppressed via the rational design of the polymer's chemical structure.

Analysis of role of erosion process of coal particles in generation of loss of incomplete combustion in fluidized bed boilers

In the herein paper the results of research carried out in the Institute of Thermal Machinery of Technical University of Czestochowa have been presented. They concern the process of combustion of coal particles in a fluidized bed combustor. The tests were carried out on a test stand which allows modelling of conditions around the fuel particle in a real object. On the basis of the registered mass loss of the particles of Polish hard and brown coal chosen, the impact of the mass flow rate of inert material with different particle size distribution and different collision velocity with burning coal particle on the rate and level of its burning out was evaluated. The obtained results enables the estimation of the influence of both parameters on the intensity of erosion and determination of its role in the generation of fine particles elutriated out of the combustion chamber. The results also facilitated the verification of the methodology [1] of calculation described in literature relating to the total mass loss of coal particles as a result of combustion and erosion. According to this methodology, the slip velocity between the char particle and the fine bed solid is the main parameter of the erosion process alongside the attrition rate constant k a .

两种生物质燃料锅炉能效测试对比分析

分别对型号为DZL4-1.25-BMF以及DZG4-1.25-BMF的生物质颗粒锅炉进行能效测试，并对其进行正反平衡测试的结果进行分析。测试结果表示型号为DZL4-1.25-BMF的链条炉锅炉热效率(78.75%)相比型号为DZG4-1.25-BMF的固定炉排锅炉(70.10%)具有更高的热效率。在燃烧参数分析下发现，固定炉排锅炉在燃烧中存在排烟中一氧化碳含量过高，氧气量供应不足的情况；而链条炉排在燃烧过程中虽然有过量空气系数过高的情况出现，但相比固定炉排锅炉，改善了燃烧状况，降低了气体未完全燃烧损失。就型号为DZL4-1.25-BMF的锅炉能效测试数据情况而言，建议在运行过程中适当调节鼓引风量，降低过量空气系数，减少排烟损失，有利于提高锅炉热效率。 Thermal efficiencies of Biomass fuel boilers of model DZG4-1.25-BMF and model DZL4-1.25-BMF were tested, respectively. Both of the thermal efficiencies were analyzed by methods of positive balance and counter balance. It was resulted that thermal efficiency of model DZL4-1.25-BMF (78.75%) was higher than the model DZG4-1.25-BMF (70.10%). According to the experimental data, an overhigh content of carbon monoxide in the exhaust gas was found in the model DZG4-1.25-BMF as shortage of oxygen occurred in the flame. But lower gas incomplete combustion loss was found in model DZL4-1.25-BMF though it performed a higher excess air factor during the test. It is suggested that it needs methods to decrease the excess air factor in order to increase the thermal efficiency of model DZL4-1.25-BMF.

宝钢一期焦炉推焦车平煤系统故障原因分析及其措施

在宝钢一期焦炉大修重建后，推焦车多次出现推焦车平煤系统故障，造成平煤系统动力回路烧损，进而造成平煤杆无法正常退回烧损，严重影响大型焦炉正常生产，选择合适的平煤系统动力控制回路及其控制策略，对大型焦炉生产稳定运行具有重要意义。 Repeatedly occurring faults of the smoothing-coal system of cake-thruster after the Baosteel’s first coke oven was rebuilt causes the burning loss for power circuit and smoothing-coal shaft of the smoothing-coal system, and undesirable consequences for the large-scale coke oven production. Choosing appropriate power control circuit and control strategy for coke-thruster smoothing-coal system has an important significance for stable production of the large-scale coke oven.

Correction of Loss on Ignition in Slag Powder by ICP-AES

In this work, with reference to the pretreatment method of the relevant national standard, we tested the content of SO3 in slag powder before and after burning by ICP-AES, then the result of burning loss was corrected by the content of SO3. The content of SO3 which was determined by this new method is fast and accurate, compared with the traditional method. We selected the wavelength of 182.0nm as spectral analysis of SO3. The detection limit of the method (3S) was 0.016 mg/L, the recovery rate of the sample was between 97%-104%, and the relative standard deviation (n=6) of the parallel samples was less than 1.05%.

Effects of waste fish oil biodiesel on diesel engine combustion characteristics and emission

In this study, the combustion characteristics, performance and exhaust emissions of conventional diesel fuel and biodiesel produced from waste fish oil (WFO) and its blends (B25, B50, B75) were compared experimentally. A single cylinder E6 Ricardo engine was used to perform the tests under steady state conditions and engine load range. In-cylinder pressure, exhaust emissions, fuel consumption and also intake and exhaust gas temperatures were recorded during experiments to analyze the gathered data. Results revealed that waste fish oil biodiesel leads to higher in-cylinder pressure together with shorter heat release rate duration when compared to common diesel fuel. Also, more stable combustion without large cycle-to-cycle variations could be reached by using biodiesel and its blends. Analyzes showed that biodiesel has about 2.92% more gross thermal efficiency and about 1.1% lower combustion loss when compared with the diesel fuel, averagely throughout all engine loads. CO emission concentration for biodiesel and its blends is reduced with gentle slope (5.2–27%) while significantly reduction occurred for UHC (11.6–70%). Oxygen content of biodiesel led to more efficient combustion and as result about 7.2% increase in CO2 averagely while NOx emission is increased also (1.9–12.8%) by using the biodiesel and its blends.

Preparation and properties of sorbents from the coals of Mongolia

The textural and sorption properties of sorbents prepared by the thermal steam activation of the semicokes of brown and black coals from nine deposits of Mongolia were studied. Their properties were compared with the properties of sorbents prepared from Borodino brown coal and Kuznetsk black coal. A common extremal dependence of the volume of mesopores and the specific surface area on combustion losses was found: a maximum specific surface area of 600–700 m2/g was reached at a combustion loss of 50–60%. Among the Mongolian samples, the sorbents obtained from the brown coals of the Baganuur, Bagankhai, and Shivee Ovoo deposits exhibited the highest surface areas and sorption capacities for iodine. Nearly linear dependence of sorption capacity on specific surface area was found. The sorbents prepared from Borodino brown coals under identical conditions were characterized by a higher degree of combustion losses because of the increased concentrations of catalytically active calcium compounds in them.

Thermal analysis of a light-duty CI engine operating with diesel-gasoline dual-fuel combustion mode

Reactivity Controlled Compression Ignition (RCCI) is one of the most promising premixed combustion modes, aimed at reducing simultaneously engine emissions and fuel consumption. In this work, the global energy balance (GEB) of a single-cylinder engine operating with dual-fuel and RCCI modes is analysed. The methodology used allows determining the energy degradation from the energy release during the combustion to the final work output, thus evaluating the performance of such combustion mode. The weight of each GEB term is analysed using two references: the injected and the burned fuel energies, thus decoupling the combustion and thermal processes. The analysis is performed by evaluating the effect of some key parameters: low/high reactivity fuel ratio, injection timing and EGR rate. The results show that increasing the low reactivity fuel leads to a better shape of the heat release rate, with a reduction of heat transfer and exhaust losses, thus improving the thermal efficiency about 1% with respect to a conventional Diesel combustion. Injection timing swept shows that a suitable optimization leads to further thermal efficiency increase up to 4%, while EGR has a limited effect. It is also concluded that there is still room for further improvement by reducing incomplete combustion losses.

Numerical study of bituminous coal combustion in a boiler furnace with bottom blowing

Results obtained by the numerical study of a solid fuel combustion scheme with bottom blowing using Ekibastuz and Kuznetsk bituminous coals of different fractional makeup are presented. Furnace chambers with bottom blowing provide high-efficiency combustion of coarse-grain coals with low emissions of nitrogen oxides. Studying such a combustion scheme, identification of its technological capabilities, and its further improvement are topical issues. As the initial object of study, we selected P-57-R boiler plant designed for burning of Ekibastuz bituminous coal in a prismatic furnace with dry-ash (solid slag) removal. The proposed modernization of the furnace involves a staged air inflow under the staggered arrangement of directflow burners (angled down) and bottom blowing. The calculation results revealed the specific aerodynamics of the flue gases, the trajectories of solid particles in the furnace chamber, and the peculiarities of the fuel combustion depending on the grinding fineness. It is shown that, for coal grinding on the mill, the overall residue on the screen plate of 90 µm (R90 ≤ 27% for Ekibastuz coal and R90 ≤ 15% for Kuznetsk coal) represents admissible values for fuel grind coarsening in terms of economic efficiency and functional reliability of a boiler. The increase in these values leads to the excess of regulatory heat losses and unburned combustible losses. It has been established that the change in the grade of the burned coal does not significantly affect the flow pattern of the flue gases, and the particles trajectory is essentially determined by the elemental composition of the fuel.

Study on the burning loss of magnesium in fiber laser welding of an Al-Mg alloy by optical emission spectroscopy

In order to study the burning loss of magnesium, a specially designed device was used to capture the spectrum emitted from the keyhole plasma in deep penetration laser welding of aluminum alloy 5052. The content of magnesium in the weld bead was measured by an electron probe micro-analyzer (EPMA). The effect of the welding parameters on the spectral intensity of magnesium plasma was examined, and the distributions of the spectral intensity of magnesium plasma in the radial and depth directions of the keyhole were investigated. Finally, the mechanism of the magnesium loss was analyzed. The results indicate that burning loss of magnesium can be monitored by spectral analysis technique. The welding parameters have a great effect on the burning loss of magnesium. The influence of welding speed on the burning loss of magnesium on the top surface is dependent on the penetration regime. The distribution of magnesium in the weld is not uniform. In the radial direction of the weld bead, the content of magnesium increases from the center to the edge of the keyhole. In the depth direction of the weld bead, the content of magnesium decreases firstly and then increases from the top to bottom. The maximum burning loss of magnesium occurs at the middle of the weld bead.

Performance analysis of a Miller cycle engine by an indirect analysis method with sparking and knock in consideration

In this paper, a full-factorial design of experiment was applied to thoroughly investigate the effects of compression ratio, intake valve closing retardation angle, and engine speed on the fuel consumption performance and power performance of the Miller cycle engine based on a quasi-dimensional simulation model. A new indirect analysis method based on formula derivation and main effect analysis was proposed to simplify the complex relationship between the design factors and the performance parameters. The definition of effective compression ratio was modified to take account of the actual mass of mixture trapped in the cylinder. The results show that the distributions of brake mean effective pressure and brake specific fuel consumption can be regarded as the re-organization results from the distributions of volumetric efficiency and indicated efficiency. The intake valve closing retardation angle has a strong negative correlation with volumetric efficiency. The modified effective compression ratio is the approximate product of the compression ratio and the volumetric efficiency, and makes obvious effects on the distribution of the indicated efficiency. Therefore the combustion process is co-evolved with the intake process in a Miller cycle engine. The further improvement of brake specific fuel consumption is mainly limited by four factors, i.e., the back flow loss, the exergy loss, the incomplete expansion loss, and the combustion loss. The improvement of fuel consumption performance is at a cost of power performance, and the trade-off between the both essentially results from the knock constraint. The engine speed makes obviously effects on both volumetric efficiency and indicated efficiency, resulting in increasing the nonlinearity of the variation of the performance parameters. However, the nonlinearity provides a possibility for a Miller cycle range extender to improve the fuel consumption performance and power performance at same time by optimizing the controlled speed.

Microstructure and magnesium burning loss behavior of AA6061 electron beam welding joints

Full penetration butt welding with different parameters was performed on 4mm thick AA6061 plates. The microstructural characteristics, element burning loss behavior and their effects on the mechanical properties of the weld beams were studied. It revealed that the weld porosity could be effectively controlled with a lower welding velocity and the crystal enlargement is rather obvious near the weld upper surface. The secondary-precipitated phase AlFeSi was observed at the crystal boundaries, whereas the strengthening phase Mg2Si within the welds is undetectable by SEM. The magnesium burning loss behavior of the welds embodies in two aspects: the decrease in magnesium content compared to the original alloy and the uneven distribution of magnesium with a decrease tendency as close to the weld surface and a symmetric growth as further away from the seam center line. The welded joints with a higher burning loss degree of magnesium are performed at a lower Vickers hardness, tensile strength, plasticity and toughness. The characteristic isotherm and convection within the molten pool during EBW were considered as the key factors that dominated the microstructure and magnesium distribution.

The effects of engine design and operating parameters on the performance of a diesel engine fueled with diesel-biodiesel blends

This paper reports the effects of engine design and operating parameters such as stroke length, ratio of bore to stroke length, compression ratio, equivalence ratio, engine load, biodiesel percentage, friction coefficient, engine speed and mean piston speed on engine performance and energy losses by experiments and a theoretical model based on the finite-time thermodynamics. In this study, the performance of a single cylinder, four-stroke, direct injection diesel engine fueled with diesel-biodiesel mixtures has been experimentally and theoretically investigated. The simulation results agree with the experimental data. After model verification, parametrical studies have been conducted for various conditions. The results showed that the biodiesel percentage and the cycle pressure ratio affect positively the engine performance. The friction coefficient has negative influence on the engine performance. The effective efficiency decreases with the increasing of the engine load, stroke length, and engine speed but effective power increases with increasing them. The effective power always increases with the increasing mean piston speed. However, the effective efficiency decreases at the constant stroke length condition, as it increases at the constant engine speed condition. The effective power and the effective efficiency increase with increasing equivalence ratio to a specified value and then begin to decrease for constant bore/stroke length conditions. The effective efficiency increases with decreasing equivalence ratio as effective power has an optimum value for constant compression ratio condition. The effects of bore/stroke length change at different conditions. At the constant compression ratio condition, the engine performance increases with increasing ratio of bore to stroke length. They are the optimum values which provide the maximum effective efficiency and maximum effective power at the other conditions. This study also reports the energy losses as the ratio of fuel energy and they are classified as friction losses, incomplete combustion losses, heat transfer losses, and exhaust losses. They are defined with respect to compression ratio. With the increasing compression ratio, the friction losses are constant for constant cycle temperature ratio and equivalence ratio, whereas the incomplete combustion losses increase at a constant cycle temperature ratio condition and are constant at constant equivalence ratio condition. The heat transfer losses increase and the exhaust losses decrease for both the conditions. The presented model could be used to optimize the performance of diesel engines fueled with biodiesel and it can be developed for all kinds of engines running at different conditions with various fuels.