Unburned Carbon Research Articles

Using methane hydrate to intensify the combustion of low-rank coal fuels

Coal mining and processing waste amounts to hundreds of millions of tons annually. Piles of coal refuse pollutes the air with dust and has a risk of self-ignition. However, it can be put to good use as an alternative energy source. To reduce the gas emissions released from its combustion and to increase its integral characteristics, this research suggests co-firing coal mining waste with a gas-vapor mixture formed upon hydrate heating. The corresponding experiments were conducted using a newly developed experimental setup with a boiler unit. The experimental findings were used to obtain an equation for predicting the flame length required for the effective combustion of waste coal. The use of methane hydrate was found to increase the fuel combustion temperature and minimize the unburned carbon. It also provided a significant reduction in the toxic gas emissions (sulfur and nitrogen oxides). A conceptual technological solution has been developed for the co-combustion of gas hydrate with coal and coal mining waste. This technology will help with heating hard-to-reach settlements, producing clean water for population and equipment, as well as recovering slime waste.

Effects of the addition of arch-supplied secondary air on the performance of the Foster Wheeler down-fired boiler: Air/particle flow, combustion and NOx emissions

This study proposes a low NOx combustion method for Foster Wheeler type down-fired boilers. The effectiveness of this technique was validated through laboratory-scale gas-particle two-phase experiments and industrial trials. The flow field characteristics within FW-type boiler furnaces equipped with arch-supplied secondary air injection nozzles were investigated. Furthermore, the application of this technique to a 660 MW subcritical FW-type boiler was examined, focusing on NOx emissions and combustion characteristics. Results demonstrate that optimizing the damper openings for F-layer and arch-supplied secondary air can significantly reduce NOx emissions by over 33 %. Additionally, increasing the mass flow rate of arch-supplied secondary air aids in reducing unburned carbon in fly ash and inducing a downward shift in the flame center within the furnace.

Effects of micro- and nano-bubbles on the flotation separation of unburned carbon from coal fly ash

ABSTRACT Nanobubble technology has found extensive use in enhancing the flotation efficiency of various minerals. The utilization of nanobubbles in flotation encompasses bulk nanobubbles, surface nanobubbles, and microbubbles; however, a comprehensive comparison of their respective roles is lacking. Furthermore, there is a dearth of studies on employing nanobubble systems in the flotation of coal fly ash. The coal fly ash characters were initially studied to reveal its ultrafine size (d50: 24.80 μm) and porous structure that includes a multitude of hydrophilic functional groups. These attributes contribute to the inadequate hydrophobicity of unburned carbon within the ash. Subsequently, the effects of different collector types, frother types, and air flow rates on the efficiency of carbon removal using conventional flotation methods were examined. Comparative analysis showed that conventional flotation using diesel oil outperformed that which employed kerosene as the collector. Additionally, higher carbon removal efficiency was achieved using MIBC, with a longer carbon chain length, as the frother, as opposed to sec-Octyl alcohol. Furthermore, a direct relationship between air flow rate and coal fly ash flotation performance was observed – higher air flow rates corresponded to improved flotation outcomes. Finally, a comparison between conventional flotation and nanobubble-assisted flotation (utilizing bulk nanobubbles, surface nanobubbles, and micro-nanobubbles) was conducted. Remarkably, micro-nanobubble flotation yielded the most promising results, with the lowest loss-on-ignition in flotation tailings (3.15%) and the highest removal efficiency of unburned carbon (85.01%). These findings satisfied the loss-on-ignition requirements of Grade I fly ash standards.

Research on electromagnetic wave absorption properties of Portland cement

In order to evaluate the electromagnetic wave absorption properties of Portland Cement, the chemical composition, mineralogical phase of Portland cement were studied by XPS, XRD and Mössbauer, respectively, and electromagnetic parameters were measured. Afterwards, the reflectivity of the hydrated cement were tested.The results showed that Portland cement exhibits some dielectric loss and weak magnetic loss at 1∼18 GHz, due to the unburned carbon and iron oxide. There are three notable theoretical electromagnetic wave absorption peaks, and the greatest absorption reaches 4.38 dB. The minimum reflectivity of hydrated Portland cement reach -17.9 dB, -17.89 dB and -12.67 dB and the bandwidth of -6 dB reach 6.28 GHz,10.74 GHz and 1.85 GHz at the thickness of 5 mm,10 mm, 15 mm, respectively. There are 3,5,7 reflectivity peaks at the thickness of 5 mm,10 mm, and 15 mm, respectively, which matched very well with the calculated interference peaks.

Modeling of Unburned Carbon in Pulverized Coal-Fired Supercritical Steam Generators

ABSTRACT In coal-fired boilers, one of the most important metrics for optimizing combustion is the proportion of unburned carbon (UC) in the ash. In most Indian power plants, it is still assessed offline through manual sample collection and laboratory analysis. The laborious processes of sample collection, preparation, analysis, and reporting require at least five to eight hours of work. The delayed results may not be useful to optimize combustion in the boiler furnace, as the boiler operating conditions may be completely different from the conditions when the samples were collected. Instead, the use of prediction algorithms may bring timely corrective action if the UC goes high. The present experimental study is taken up to obtain a correlation between UC and corresponding relevant boiler operational parameters and on the residence time of coal particles in the boiler furnace. Multiple regression analysis is performed using ANOVA tools. One hundred and ninety-four sets of coal, ash samples and boiler operating parameters are collected from 07 supercritical units. Coal proximate, coal fineness and ash UC analysis are carried out. The analyzed results and collected boiler operational data are statistically analyzed using Microsoft Excel’s ANOVA tool to understand the dependent behavior of UC on the boiler operational parameters and fired coal characteristics. The empirical equations are proposed for the prediction of UC in bottom and fly ash for supercritical boilers. Additionally, fresh 20 sets of coal, ash samples, and related operating data are gathered for the validation of the proposed empirical equations. For additionally collected samples, the predicted results are compared with the offline measured laboratory results. The maximum deviation between the predicted and laboratory results are within the range of ± 0.40% and ± 0.24% for bottom and fly ash samples, respectively.

Effects of modified coal gasification fine slag on the processing and mechanical properties of natural rubber composites

AbstractCoal gasification fine slag (CGFS) is rich in unburned residual carbon, silica and alumina, and has a large specific surface area, making it a potential polymer‐reinforcing filler. Tea polyphenol (TP)‐modified coal gasification fine slag (TP‐CGFS‐T) was prepared using flotation and modification methods in this study. The effects of unmodified and modified CGFS‐T on the sulfurization performance, processing properties, thermal stability, fracture morphology, and mechanical properties of natural rubber composite materials were investigated. Results indicated that after TP modification, CGFS‐T exhibited highly uniform dispersion on the surface without the agglomeration of fillers. When the dosage of TP‐CGFS‐T was 20 phr, the comprehensive performance of the natural rubber (NR) composite material was optimal, with a tensile strength of 12.12 MPa, the elongation at break of 1208.83%, the tear strength of 30.94 kN/m, and the shore hardness of 38.7 A. As the amount of TP‐CGFS‐T increased, the scorch time of NR increased, which enhanced the processing safety of rubber. This study provides a strategy for treating CGFS, which can both reduce the pollution caused by CGFS and save costs for NR composite materials.Highlight The CGFS is separated into concentrate and tailings by flotation. The compatibility between fillers and the matrix is enhanced by TP modification of CGFS‐T. The composite materials show excellent mechanical and processing properties.

Mechanical properties and microstructural discrepancies of concrete with flotation-modified fly ash from circulating fluidized bed and pulverized coal furnaces

Fly ash (FA) is a by-product of coal-fired power generation in thermal power plants. Disparities in coal types and combustion furnaces result in varying levels of unburned carbon in FA, hindering its effective utilization. In this study, FA from a circulating fluidized bed furnace (CFBFA) and pulverized coal furnace (PCFFA) was modified using froth flotation technology, and the influence of the modified FA from the froth flotation process on the mechanical properties and microstructural discrepancy of concrete was analyzed through the preparation of mortar and cement paste specimens. The results indicated that the flotation process proved effective in reducing the unburned carbon content in FA, with modified PCFFA showing higher surface area and fluidity, opposite to CFBFA. Notably, the flotation process altered CFBFA's mineral content, reducing CaSO4·2 H2O from 26.6% to 7.5% and increasing CaSO4, enhancing hydration and strength in concrete applications. The optimal FA dosage was found to be 20%, with CFBFA specimens displaying superior compressive strength across all tests. Conversely, the modified PCFFA exhibited low activity, making it challenging to reach the desired strength after 28-d. This study serves as a theoretical foundation for the application of highly unburned carbon FA in construction engineering and promotes the circular development of FA resources.

Applicability analysis of burners arrangement for an improved entrained-flow fine slag gasifier

Fine slag with high carbon content is unsuitable for brick-making or road paving and is usually deposited in piles or landfills. The atmospheric entrained-flow gasification technology can make use of the unburned carbon in fine slag, thereby resolving the problem of wasted resources and environmental pollution caused by waste fine slag. The arrangement of burners has an impact on the flow field within the gasifier, which subsequently affects the gasification performance. It is important to find a suitable burner arrangement for different gasification raw materials. This study investigates the gas–solid flow characteristics in 10,000 Nm3/h fine slag entrained-flow gasifiers using a combination of two-phase experiments and numerical simulations. The flow fields were compared in detail for three different burner arrangements. The results indicate a clear central tangent circle under the co-biased burner arrangement, which leads to the highest particle concentration and swirl intensity near the membrane wall. This condition is most conducive to slag formation. No rotating flow field is generated in the gasifier under the opposed and counter-biased burner arrangements. The high-temperature region is located near the top of the chamber. Additionally, the residence time of fine slag is short. These factors make it unsuitable for powder gasification. The results will be helpful to the design and operation of entrained-flow powder-feedstock gasifiers with multiple burners.

Study of the effect of airflow rate and agitation speed on entrainment of ash particles in bottom ash flotation

To enhance the recovery and grade of the final product, reducing the entrainment of the hydrophilic particles during flotation is critical. We conducted the improvement of entrainment to reduce the amount of ash in the concentrate with the purpose of recovering high-quality unburned carbon from the bottom ash and reusing it as fuel in power plant. In this study, we investigated the effects of airflow rate and agitation speed on the entrainment of hydrophilic particles. In the self-aerating flotation machine, it was difficult to independently control the agitation speed and airflow rate, resulting in the degree of entrainment of 0.74. By independently controlling the airflow in which hydrophobic particles can float under conditions of the degree of entrainment with 0.7 (low agitation speed: 900 rpm), the combustible recovery and unburned carbon content of concentrate were 93.71% and 93.60%, respectively. The degree of entrainment was found to be 0.57, and entrainment could be minimized through independent control of airflow rate and agitation speed. To minimize entrainment, it is effective to inject air that can suspend hydrophobic particles in a low agitation speed condition.

Waste plastic oil as an alternative fuel: A review

Today, with the high population density of the world, the energy demand is increasing continuously. Global dependency on fossil fuels is very strong and there is a compelling need to reduce our energy consumption in order to offset greenhouse gas emissions. Due to regularly increasing prices of fossil fuels alternative fuels are needed to fulfill the requirements of developing countries like India. Plastics in today's world have become crucial. They are excessively used in industry, as well as in households and other fields due to their lightweight, durability, and design flexibility. Plastic demand is growing day by day, which now poses a huge environmental threat. The current study summarizes the use of WPO (waste plastic oil) in the diesel engine and also concludes the combustion, performance, and emission parameters. After an exhaustive literature search, some interesting results have been found. The study reveals that when using WPO as an alternative source in a diesel engine, the combustion, performance, and emissions are similar to those using conventional diesel fuel. An enhanced BTE (brake thermal efficiency) and reduced emissions of unburned hydrocarbons (UBHC) and carbon monoxide (CO) are reported.

Low-carbon fuel reburning for CO2 and NOx reduction in pulverized coal firing system

Using low- or zero-carbon fuels is necessary to reduce CO2 emissions. Gas reburning technology can be applied to existing coal boilers to reduce not only CO2 but also NOx emissions. In this study, we confirmed the gas reburning effect using lab-scale equipment based on the consumption coal used in real-scale boilers, with the aim of practical application. Bituminous coal was used as the reference fuel, and sub-bituminous coal was blended to determine whether coal blending has an effect on NOx emissions. This was conducted to optimize the coal blending ratio and gas reburning technology for NOx emission reduction and quantify the NOx reduction by the two methods. Blending sub-bituminous coal reduced the unburned carbon (UBC) content, because of its high volatile matter content. Moreover, NOx emissions decreased as the ratio of sub-bituminous coal increased. In terms of the reburning effect, although UBCs increased with the addition of methane, NOx emission decreased by up to 96.05 %. The conversion ratio, defined as the NOx formation ratio of the total fuel N injection, was used to separate the NOx reduction effects of the two methods. Thus, gas reburning in the ammonia co-firing system of coal-fired power plants can significantly reduce NOx emissions.

Оценка золошлаковых отходов как источника загрязнения окружаюшей среды и источника вторичного сырья

Introduction. Currently, more than 500 million tons of fly ash have been accumulated on the territory of the Republic of Kazakhstan, the volume of which will increase to one billion tons by 2030. Such accumulation of fly ash in storages creates a powerful anthropogenic impact on the biogeocenosis. A significant proportion of these man-made materials are formed during the burning of Ekibastuz coals. There is practically no processing of ash and slag waste on an industrial scale. For various reasons, ash dumps are not used in Kazakhstan, because the physico-chemical properties have been very poorly studied, in addition, during their processing, other wastes or ash dumps unsuitable for use are obtained from these wastes, because they contain a lot of unburned coal. As of 01.01.2020, the share of recycled, reused, burnt ash and slag waste in Kazakhstan amounted to 0.7%. The relevance and significance of this problem is due to the fact that man-made waste from CHP plants is not sufficiently processed, and current ash waste accumulates and occupies huge areas, which removes them from land use. Knowledge of the chemical composition of the ash will allow it to be used to obtain building materials. The purpose of this work is to study the properties of ash and slag waste during the burning of coal from the Ekibastuz deposit in Kazakhstan, to assess them as a source of environmental pollution, to determine the possibility of obtaining demanded building materials from them. Research methods. To determine the phase composition of the studied material, an upgraded diffractometer DRON-3M on CuKa radiation with software was used. Radiographs of the sample were obtained in the range of 2° (angles) from 10 to 70°. The chemical composition was determined using an energy dispersion spectrometer “EDX-8000”. Micrography of fly ash was taken on a scanning electron microscope Superprob-733. Research materials. Ash and slag waste from the burning of coal from the Ekibastuz deposit in Kazakhstan. Research results and discussion. The physical characteristics of ash have been established: specific surface area – ~200 m2/kg, true density – 2.1 g/cm3, bulk density – ~780 kg/m3. Fractional composition: the highest content of particles with a size of 100 microns (25.8%), 80 microns (12.12%), 50 microns (21.46%) and 45 microns (21.38%); at the same time, unburned carbon is concentrated in large fractions, glass phase – in small ones. Analysis of the chemical composition of Ekibastuzky ash allowed to find out the composition of coal minerals. The main components are silicon and aluminum oxides, and there is also a large amount of iron oxide. Knowledge of the chemical composition of ash allows it to be used in the production of building materials. Conclusion. The results of the conducted studies have shown the possibility of using ash and slag waste as secondary raw materials in the construction of road materials in order to reduce the anthropogenic load on the environment.

Reuse of unburned carbon as filler substitutes in some rubber goods

Reuse of unburned carbon as filler substitutes in some rubber goods

Investigating the potential of a waste-derived additive for enhancing coal combustion efficiency and environmental sustainability in a circular economy

This study examines the impact of a waste-derived additive from alumina and shale oil production on the performance of coal combustion. The effects of individual additive components were investigated under oxidant-limited and oxidizing conditions using the isothermal flow reactor (IFR) equipped with gas analysers. The raw materials, as well as fly chars/ashes derived from the IFR, were characterized using standard physicochemical analysis, oxide analysis, oxygen functional group determination, the ash fusion test, thermogravimetry, scanning electron microscopy and energy dispersive X-ray spectroscopy. Results from experiments conducted under oxidant-limited conditions demonstrated that the analysed additive, at a 1% share, increased hydrogen content in char by over 3.5 times (from 600 ppm to 2160 ppm) and enhanced methane conversion by nearly 20%. Under oxidizing conditions, the additive reduced unburned carbon loss by approximately 50%, emissions of NOx from 400-460 ppm to 340–390 ppm and SO2 from 1410-1475 ppm to 1325–1410 ppm. The study emphasized the influence of moisture on thermochemical processes, confirming that a certain amount of water vapour accelerates the conversion of H2, SO2, and NOX. The analysis supported the commercial utilization of the additive from economic, environmental, and operational standpoints.

Effect of excitation Strouhal number on a backward-inclined jet flame in crossflow

Combustion is often accompanied by environmental pollution due to incomplete reaction. A non-excited flame usually exhibits poor combustion performance with features of diffusion flame such as dual-peak temperature distributions and large combustion product concentrations. Efficient fuel-air mixing has been identified as a key factor in mitigating this issue. The present study investigated the effects of the acoustic excitation Strouhal number on the combustion performance of a backward-inclined jet flame in crossflow. A loudspeaker was used to induce jet pulsations with excitation Strouhal numbers ranging from 0.47 to 1.54 at a pulsation intensity of 0.90. Time-averaged and instantaneous flame images were captured using digital cameras. A customized R-type thermocouple and a commercial gas analyzer were employed to analyze the thermochemical structures. A critical excitation Strouhal number of approximately 0.9, distinguishing two characteristic flame modes: strongly affected flame (SA flame) and weakly affected flame (WA flame), was found. At excitation Strouhal numbers lower than the critical value, the SA flame featured single-peak temperature profiles and low unburned hydrocarbon, carbon monoxide, and nitric oxide emissions. The combustion performance was significantly improved due to the strong mixing effect induced by the acoustic excitation. The WA flame appeared at excitation Strouhal numbers higher than the critical value. It exhibited dual-peak temperature distributions and slightly improved combustion performance. The dynamic behavior and emissions of acoustically excited jet flames offered a fascinating insight into the influence of excitation Strouhal numbers on combustion characteristics. More excitation conditions were expected for future research.

Biogas intake pressure and port air swirl optimization to enhance the diesel RCCI engine characteristics for low environmental emissions

Exhaust emission and combustion control in RCCI (reactivity-controlled compression ignition) focused mainly on the direct-injected fuel parameters, urging to investigate the advantages of port-fuel intake parameters. The engine was modified for port injection of Biogas at the valve and RCCI mode. The influence of port swirl ratio (PSR, 0 – 80%) and biogas injection pressure (BIP, 1 – 4 bar) on the diesel RCCI combustion and emissions was tested and optimized at varied loads and 1600 rpm in a port injection at the valve (PIVE) approach. Established kinetic mechanisms were combined with multi-objective optimization to further investigate, predict, and analyze emissions occurrence and trade-offs for reduced environmental impacts. The results show that the radiation absorption triggered by increased CO2 lowers combustion temperature, resulting in prolonged ignition. Setting the airflow to swirl lowers the in-cylinder pressure at elevated BIP while raising the heat generated across the BIPs. Increasing the PSR slows the combustion while BIP speeds up the process. BIP and PSR show great trade-off reduction ability among all emission parameters. The optimum unburned hydrocarbon, nitrogen oxide, particulate, and carbon monoxide emissions for the injection at the valve were found to be 109.58, 0.577, and 2.336 ppm, and 0.103%, respectively, at low-load, low-BIP, and high-PSR. The emissions were lowered by 6.58, 91.26, 80.65, and 13.45% compared to the premixed RCCI mode, respectively. Therefore, introducing low-pressure biogas amid high swirling air at the valve elevates the in-cylinder condition while lowering the emissions, mitigating their environmental implications.

Intensification of flotation separation process of residual carbon from coal gasification fine slag using ultrafine carbon particles conditioning

ABSTRACT Coal gasification fine slag (CGFS) is a high-ash product with high content of residual carbon. Flotation is a common method to separate residual carbon from CGFS. However, conventional flotation is difficult to effectively remove residual carbon due to the intimate interlock between carbon and ash components in CGFS and the developed pore structure of residual carbon. In this work, a separation method was proposed using ultrafine carbon particles during conditioning to achieve the intensification of ash-carbon flotation separation from CGFS. The flotation results showed that employing ultrafine carbon particles conditioning pulp effectively increase the removal rate of unburned carbon by nearly 20%. To investigate the mechanism of the effect of variable contents of ultrafine carbon particles on the decarburization performance of CGFS, the mercury intrusion porosimeter and a self-made laboratory attachment process observation system were used, indicating that the proposed method reduced the cumulative pore volume of CGFS from 1.27 to 1.09, a 15% decrease. During the conditioning process, the ultrafine carbon particles could follow the fluid flow into the residual carbon pores, which prevented the flotation reagent entering the pores. Thus, this avoids waste of flotation reagents and improves flotation performance.

Facile Route for Effective Separation and Full-Scale Recycling of Fly Ash and Unburned Carbon.

The synchronous production of high-quality unburned carbon concentrate and cleaned ash from high LOI (loss on ignition) fly ash without yielding secondary solid waste is a dilemma issue. In this study, a viable flotation process with one rougher and two cleaners is developed for simultaneously obtaining carbon concentrate with a yield of 18.00% and an ash content of 17.49% and cleaned ash with a yield of 82.00% and a LOI of 4.63% from fly ash, reaching 84.72% of combustible substance recovery and 80.66% of flotation perfection index. The characteristic analyses of the stage by stage releasing products using laser particle size analysis, XRF, XRD, and SEM-EDS demonstrate that the inevitable factors that lead to a remaining higher ash content in the one-step flotation carbon concentrate are the random entrainment of mineral particles in the size range of 0-20 μm, especially the quasi-colloidal parts within 0-12.5 μm and the weak selective collection of fine-grained conjoined granules in the size range of 0-40 μm. Consequently, at least two cleaning steps are required for the effective separation of unburned carbon and ash. Furthermore, batch flotation test results show that diesel is superior to kerosene in the collection of unburned carbon, with an optimum dosage of 800 g/t; no. 2 oil acts more positively than MIBC for the separation of unburned carbon and ash, with an optimal dosing amount of 600 g/t; the optimum pulp concentration and flotation time are as follows: 100 g/L and 3.5 min for the rougher, 45 g/L and 2 min for the first cleaning, and 30 g/L and 3 min for the second cleaning. This study provides an economically feasible technological solution for the full-scale recovery of high-LOI fly ash in one step and avoids the problem of secondary solid waste that would have been generated in previous studies.

A relative comparison of HCCI, PCCI, and RCCI combustion strategies: an alternative fuels perspective

Low temperature combustion (LTC) strategies have the potential for simultaneous reduction in oxides of nitrogen (NOx) and soot emissions while achieving higher thermal efficiency. Commercial widespread implementation of LTC strategies demands addressing several challenges, including narrow operating load range, lack of ignition timing control, and reducing high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. These challenges could be because the conventional engine design and fuels cannot adapt well to LTC modes. Thus, replacing conventional diesel fuel with suitable alternative fuels for LTC strategies is essential. In the present work, three LTC strategies, Homogenous Charge Compression Ignition (HCCI), Premixed Charge Compression Ignition (PCCI), and Reactivity Controlled Compression Ignition (RCCI), are compared with conventional diesel combustion in a production, light-duty diesel engine from an alternative fuel perspective to come up with a befitting strategy and fuel to achieve wider operating range and lower emissions. The fuel selection strategy based on the fundamental fuel property requirements of the three LTC strategies has been discussed in detail. The baseline reference data is fixed by comparing three LTC strategies with conventional diesel combustion using diesel and gasoline as reference fuel at 40% load, the maximum common achievable load among the three LTC strategies. This is followed by an investigation of the effect of alternative fuels across three LTC strategies to address the shortcomings of the LTC strategies. The results show that the engine operating load range could be extended, and HC and CO emissions are reduced significantly with alternative fuels in the three LTC strategies.

Response Analysis of an Experimental Study on the Effect of Speed and Premixed Fuel Ratio on Performance and Emissions in RCCI Engine

Even though CI engines are more efficient than SI engines due to their ability to operate at a greater compression ratio, a leaner charge, and lower throttle losses, they have higher PM and nitrogen oxide emissions. The induction system modification with fuel port injection is used as a parameter in RCCI engine operations for controlling emission through in-cylinder charge reactivity and combustion phasing. By varying the amount of hydrous bioethanol in the premixed fuel injection ratio, the engine’s performance and emissions are greatly affected. In this study, an experimental investigation of a triple-fuel RCCI engine running on port-injected gasoline-bioethanol blend and direct-injected diesel fuel was conducted. Taguchi’s experimental design method was employed to assess the impact of various independent variables utilizing three set levels and two factors with the L9 orthogonal array. From the findings, the delta value shows the highest average response for each factor. Engine speed has the largest effect on the signal-to-noise ratio (SNR) with the (delta value of: 10.7446, rank = 1), and the delta value of 38.96, rank = 1, has the largest effect on the response of means at engine speeds of 3000 rpm. The premixed fuel ratio of G25BE75 (delta: 87.30, rank = 1) has the largest effect on the standard deviation. The lines are not parallel in all emission and performance cases except for Tb and CO2, which are close to parallel. The best means in engine speed and premixed blended fuel ratio were NOx, CO, HC, and brake power. At 3000 rpm, the speed had the larger main effect plots of SNR. The premixed fuel ratio of G25BE75 had higher main effect plots for means and standard deviations. The residues appear to have been dispersed normally based on a straight line by using a normal probability plot. The data are normally distributed, as demonstrated by the normal probability plot, and the factors had an impact on the response. Conferring to the experiment result, a high engine speed and higher ethanol content in the RCCI premixed fuel are preferred for reducing nitrogen oxides (NOx) and carbon dioxide (CO2), while unburned hydrocarbons (UHCs) and carbon monoxide (CO) showed a slight increase.