NOx Formation Characteristics Research Articles

Distinguishing the vertical air-staging low-NOx function of secondary air for suspension combustion within an industrial-scale coal-fired reversal grate furnace

The numerous coal-fired grate furnaces in China, which were designed to partition primary air on the grate and arrange secondary air in the freeboard for air-staging combustion, suffered from poor burnout and high NOx. However, secondary air was conventionally closed or set at marginal openings in real operations and no investigation was reported to explain why. Upon these off-design secondary-air circumstances, industrial-scale tests and modeling investigations were performed for a 75 t/h coal-fired reversal grate furnace at secondary-air ratios of 0 %, 3 %, 6 %, 10 %, and 16 %, respectively. The primary aims were to (i) uncover its combustion and NOx formation characteristics with varying secondary air and (ii) confirm whether secondary air acted on a real air-staging function in reducing NOx. Flow-field deflection and asymmetric combustion were found in the furnace, with the upward gas entirely deflecting towards the rear side. The front-half furnace was filled with a large but weak recirculation zone without effective combustion, acting on a huge dead zone to waste the furnace-space utilization. With increasing the secondary-air ratio, the upward gas deflection deteriorated continuously. Layer combustion worsened while suspension combustion first strengthened and then weakened. NOx emissions displayed an ascent-to-descent trend. Carbon in slag raised while carbon in fly ash decreased. Among the five case setups, the 0 % setting (i.e., fully closing secondary air) exhibited the lowest NOx emissions and burnout loss. Compared with the habitual 6 % setup, fully closing secondary air not only reduced NOx emissions by 22 % but also improved a little burnout. These trends meant that opening secondary air only strengthened suspension combustion for burning well fly ash while raised both NOx and total burnout loss. Secondary air thus failed to role as an air-staging function in reducing NOx.

Study on Soot and NOx Formation Characteristics in Ammonia/Ethylene Laminar Co-Flow Diffusion Flame.

The formation of soot and NOx in ammonia/ethylene flames with varying ammonia ratios was investigated through experimental and numerical analysis. The spatial distribution of the soot volume fraction and NOx concentrations along the flame central line were measured, and the mechanism of soot and NOx formation during ammonia/ethylene co-combustion was analyzed using CHEMKIN 17.0. The experimental results indicated that the soot volume fraction decreases with an increase in ammonia ratio, with the soot peak concentration occurring in the upper region of the flame. The distribution of NOx is complex. In the initial part of the flame, a higher concentration of NOx is generated, and the lower the ammonia ratio, the higher the concentration of NOx. As the combustion process progresses, the concentration of NOx initially decreases and then subsequently increases rapidly, with higher ammonia ratios leading to higher concentrations of NOx. The addition of ammonia results in a decrease in CH3, C2H2, and C3H3, and an increase in CN concentration. This leads to a transformation of carbon atoms within the combustion system, reducing the available carbon for soot formation and suppressing its generation. A higher ammonia ratio increases the likelihood that NH3 will be oxidized to N2, as well as increasing the probability that any generated NO will undergo reduction to N2 through the action of the free radicals NH2 and NH.

Studies on NOx formation and reduction characteristics in high-ash, low-volatile coal combustion by mechanism experiments and industrial-scale trials

Mechanism experiments were performed to investigate NOx formation and reduction during the combustion of high-ash, low-volatile coal. Additionally, industrial-scale trials were conducted to study the effects of air-staging degree on the combustion and NOx emission characteristics of high-ash coal on a 350 MW supercritical down-fired boiler. The results showed that the total BET specific surface area, total pore volume and porosity values of high-ash coal (HAC) and ultra-high-ash coal (UHAC) were all larger than those of normal-ash coal (NAC), whereas NAC contained more N-5 and N-6 than HAC and UHAC. The carbon layer structure of HAC char was less ordered and the content of hydroxyl group was relatively high. The overall NO reduction ratio obtained using the HAC char was higher than the value for the UHAC char. However, in the high temperature range of 1300–1400 °C, NO reduction associated with UHAC char was accelerated because of catalysis by ash. On increasing the excess oxygen ratio λ from 1.0 to 1.2, the char-N conversion shown by the UHAC char slowly increased and remained the lowest among the three chars. When burning UHAC, as the ratio of secondary to tertiary air fluxes, Rst, was decreased from 1.56 to 0.57, heating of the fuel-rich coal/air flow slowed and pulverized coal combustion was inhibited. The situation associated with HAC was different. At the Rst of 1.11, the ignition distance of fuel-rich flow was the shortest at 1.50 m, and the overall temperature in the furnace was the highest. However the NOx emissions at the furnace exit were as high as 715 mg/m3 (6 % O2) in this condition. Decreasing Rst to 0.57 reduced this value to 634 mg/m3 (6 % O2) with carbon levels in the fly ash and slag of 5.17 % and 3.67 %, respectively. Air-staging combustion is evidently a reasonable approach to controlling NOx emissions when burning HAC. While for UHAC, it was necessary to appropriately reduce the air-staging degree to enhance combustion and maintain low NOx emissions.

Numerical investigation on NOx formation of staged oxy-fuel combustion in a 35 MW large pilot boiler

In this study, high-fidelity simulations are conducted on a 35 MW pulverized coal oxy-fuel boiler to investigate NOx formation characteristics under staged oxy-fuel combustion, including both fuel-staged and oxygen-fuel two-way staged modes. Detailed volatile components are considered by using the chemical percolation devolatilization model. A skeletal reaction mechanisms consisting of 35 species developed for fuel-NOx formation under oxy-fuel conditions are employed for the gas phase combustion and NOx modeling. The radiative property models are also optimized for oxy-fuel combustion. The results show that in the fuel-staged mode, a reduction atmosphere is established in the reburning zone to reduce the NOx concentration in the flue gas. A reduction of 5.6% in the average NO concentration at the furnace outlet is observed relative to the baseline oxy-fuel case. Moreover, the application of oxygen-fuel two-way staged combustion leads to a further reduction in NOx formation. The average NO concentration at the furnace outlet is decreased by 17% compared to the baseline oxy-fuel case. Pathway analysis indicates a reduction in the NO formation pathway involving HCN → NCO → NO, while the NO reduction pathway of NO → HCN is enhanced.

Insight into NOx formation characteristics of ammonia oxidation in N2 and H2O atmospheres

For the practical combustion of ammonia (NH3) in air, ammonia jet entrains the combustion product inside the furnace, and the reaction zone is diluted with a significant amount of H2O; thus, the impact of H2O on NH3 oxidation cannot be ignored. In this study, NH3 oxidation was conducted under N2 and H2O atmospheres in a jet-stirred reactor. Experimental and numerical investigations were conducted to analyze the impact of various parameters, including the temperature, equivalence ratio, H2O volume fraction, and residence time. The NO formation is enhanced as T increases, while it is inhibited as Φ or XH2O increases. The N2O and NO concentrations are an order of magnitude when T ≤ 1375 K, and the peak N2O concentration occurs at T ≈ 1375 K and Φ = 0.5. The presence of 20 % H2O reduces NO and N2O concentrations by 61.5 % and 29.5 %, respectively, at Φ = 0.5 and T = 1375 K. To reduce NOx formation with an acceptable concentration of unburned NH3, the recommended operation condition of NH3 oxidation is obtained. This study presents a new underlying understanding of the formation of NOx during NH3 oxidation under N2 and H2O atmospheres.

Experimental Study on NOX Formation Characteristics in Flue Gas Recirculation Combustion Process of S-CO2 Coal-Fired Boiler

ABSTRACT Flue gas recirculation technology and air-staged combustion technology are both effective methods for reducing the production of NOX in coal-fired boilers. However, the synergistic effect of air-staged combustion technology and flue gas recirculation technology on NOX generation characteristics in S-CO2 boilers needs further study. The formation characteristics of NOX in the main combustion zone of coal combustion were studied experimentally when flue gas recirculation and air-staged combustion were combined. The results indicate that as the recirculation flue gas is injected at deeper levels, there is a gradual decrease in the concentration of NOX along the path, And the concentration of O2 also decreases gradually. The concentration of NOX decreases as the excess air coefficient decreases. The concentration of O2 increases as the excess air coefficient increases. Additionally, the NOX concentration at the furnace outlet increases with the increase of the excess air coefficient. Along the axial direction of the one-dimensional flame combustion furnace, the NOX production along the way and the NOX concentration at the outlet decrease with the increase of the flue gas recirculation position. Flue gas recirculation in air-staged combustion is an effective method for reducing NOX emissions. The positioning of flue gas recirculation significantly impacts NOX emissions. The NOx concentration is lowest when the flue gas recirculation rate is 27% and the mixing position of the recirculated flue gas is 300 mm with an excess air coefficient of 0.8.

Numerical analysis and flamelet modeling of NO[formula omitted] formation in a thermodiffusively unstable hydrogen flame

In a thermodiffusively unstable premixed hydrogen flame, cellular flame structures exist due to the strong differential diffusion of hydrogen featuring wide ranges of curvature and strain rate. NOx formation pathways are directly affected by the complex cellular flame structures as different species have different sensitivities to differential diffusion effects and curvature. In this work, the NOx formation characteristics of a thermodiffusively unstable laminar premixed hydrogen flame are investigated. At first, the NOx formation characteristics in the tangential and normal directions of the flame front are analyzed, focusing on the effects of curvature. Then, reaction path analyses are conducted to identify the relevant pathways and elementary reactions that pre-dominantly contribute to the formation of NOx pollutants. To investigate the effects of curvature on NOx formation, the reaction fluxes and the elementary reaction rates are calculated by conditioning on the curvature value. Finally, the performance of a flamelet model in predicting the NOx species in the thermodiffusively unstable premixed hydrogen flame is evaluated through an a priori analysis. The results show that curvature directly affects NOx formation, particularly the dominant NNH and N2O reaction pathways while the contribution of the thermal-NO pathway is found to be overall negligible. The NOx species are mainly formed in positively-curved flame segments where the flamelet model gives good predictions, while discrepancies with respect to the model exist in the negatively-curved flame regions. The reason for this is clarified through a chemical timescale analysis and a conditional reaction path analysis.

Combustion and NOx formation characteristics from a 330 MWe retrofitted anthracite-fired utility boiler with swirl burner under deeply-staged-combustion

In order to achieve peak carbon dioxide emissions and carbon neutrality goals, a higher requirement is put forward for coal type adaptability medium, load stable combustion performance, and pollutant emission for wall-fired boiler with swirl burners. In this work, through industry experiments, the combustion characteristics of a retrofitted wall-firing mode 330 MWe power unit feed with anthracite were investigated. The combustion system was retrofitted employing the centrally fuel-rich (CFR) swirl burner and deeply-staged combustion technology. The experiment data were measured, including flue gas temperature and composition, furnace temperature, and the main operational parameter under high-load (300 MWe), medium-load (230 MWe), and low-load (150 MWe) conditions. The stable combustion of anthracite is achieved at various loads. With the excessive air coefficients of the main combustion region increase, the corresponding second air damper opening increase under high-load condition or over-fire-air damper opening decrease, both the flue gas temperature and heating rate of pulverized coal increase advance the ignition and promote the stable combustion and burn-out of anthracite coal. In the initial combustion stage, the O2 given into the chamber increase, both O2 consumption rate and CO concentration decrease, but NOx concentration increases. While in the later stage, both the O2 and CO concentration tend to become flat. Meanwhile, the O2 concentration is lower than 2.1%, the CO concentration maintains a relatively high level, and NOx production is inhibited effectively and becomes flat gradually. With the excess air coefficient increase, the temperature in the main combustion region increases, and the difference in furnace temperature between the burn-out region and the main combustion region diminishes. The unburned carbon content in fly ash and exhaust gas temperature decreases, while NOx emission increases. There is little difference for the flue gas temperature distribution in the side-wall region, and the measured O2 concentration is always higher than 3.5% with the different mass flux of secondary air and over-air-fire. With decreasing load, the NOx emission decreases from the highest 1392.66 to the lowest 958.38 mg/m3 (O2 6%), and the boiler efficiency improves. Compared with high-load and medium-load, the slagging tendency of the water wall is lower under low-load condition.

Investigations into NOx Formation Characteristics during Pulverized Coal Combustion Catalyzed by Iron Ore in the Sintering Process

Sintering accounts for about 50% of the total NOx emissions of the iron and steel industry. NOx emissions from the sintering process can be simulated using the emissions from coke combustion. However, the generation and emission law for NOx burning in the sintering process of pulverized coal is still not clear. The formation characteristics of NOx during coal combustion catalyzed by iron ore fines and several iron-containing pure minerals were studied in this paper. The results showed that iron ore fines can improve the NOx emission rate and increase the total NOx emissions during coal combustion. The type and composition of the iron ore fines have an important impact on the generation and emission of NOx in the process of coal combustion. The peak concentration and emissions of NOx in coal combustion flue gas with limonite, hematite or specularite added increased significantly. The peak value for the NOx concentration in the coal combustion flue gas with magnetite or siderite added increased, but the emissions decreased. Therefore, the generation of NOx in the sintering process can to a certain extent be controlled by adjusting the type of iron-containing raw materials and the distribution of the iron-containing raw materials and coal.

Industrial measurement of combustion and NOx formation characteristics on a low-grade coal-fired 600MWe FW down-fired boiler retrofitted with novel low-load stable combustion technology

The randomness and intermittence of solar and wind power generation require coal-fired thermal power boilers that have a low-load stable combustion capacity. This study proposed a novel low-load stable combustion technology in which the oil secondary air flow is arranged parallel to the fuel-rich coal/air flow and participates in pulverised coal combustion during boiler operation. The method was applied to a 600 MWe down-fired boiler manufactured with the technology of Foster Wheeler Corp. Full-scale industrial measurements of furnace flue gas temperature, fuel-rich coal/air flow ignition distance, and distribution characteristics of NOx, O2, and CO in the furnace at loads of 200, 240, and 540 MWe were performed. The results showed that the boiler can stably operate without oil support at 240 MWe (40% rated load) and 200 MWe (33% rated load) respectively burning a blended coal of anthracite and lean coal, and blending bituminous coal. At loads of 200, 240, and 540 MWe, the fuel-rich coal/air flow ignition distances were, respectively, approximately 1.4, 1.7, and 1.3 m. NOx emissions at the furnace exit were 406, 407, and 730 mg/Nm3 (O2 = 6%), and the boiler thermal efficiencies were 92.42%, 92.45%, and 90.58%, respectively. This novel technology presents the characteristics of high efficiency and low NOx emission while realizing low-load stable combustion of down-fired boilers.

Experimental evaluation on NOx formation and burnout characteristics of oxy-fuel co-combustion of ultra-low volatile carbon-based solid fuels and bituminous coal

Pyrolyzed semi-coke (SC) powder and gasification residual carbon are usually regarded as solid wastes, which feature high NOx formation amount and inferior burnout performance during burning process. Oxy-fuel co-firing of these ultra-low volatile carbon-based solid fuels (LVFs) with bituminous coal (BC) could reduce the NOx generation and realize the carbon capture to a large extent. However, the NOx formation and burnout features of oxy-fuel co-combustion of BC and LVFs are still unclear. Here, a two-staged drop-tube co-firing experimental system was employed to probe the oxy-fuel co-combustion characteristics of various blends. The experimental results show that the low ash melting temperature of coal-water-slurry gasification residual carbon yields an increase in Cfh with the temperature of burnout zone. The Cfh of BC/SC blend is decreased by 64.3% with the oxygen flow rate of primary air raised from 0.25 to 0.45 L min−1, which is the largest among all blends. The rise of difference between tube lengths in furnace of BC and LVF generates a decrease in NOx formation and an increase in Cfh. The present research could offer guidance for clean and efficient utilization of carbon-based solid wastes using oxy-fuel co-combustion technique, together with the encouraged development of carbon capture technology.

NOx Formation Characteristics for Cocombustion of Rice Husk and Coal at High Temperature

NOx Formation Characteristics for Cocombustion of Rice Husk and Coal at High Temperature

Numerical Simulation of the Influence of CO2 on the Combustion Characteristics and NOX of Biogas

The existence of inert gases such as N2 and CO2 in biogas will reduce the proportion of combustible components in syngas and affect the combustion and NOX formation characteristics. In this study, ANSYS CHEMKIN-PRO software combined with GRI-MECH 3.0 mechanism was used to numerically simulate the effects of different CO2 concentrations (CO2 volume ratio in biogas is 0–41.6%) on flame combustion temperature, flame propagation speed and nitrogen oxide formation of complex biogas with low calorific value. The results showed that when the combustion reaches the chemical equilibrium, the flame combustion temperature and flame propagation speed decrease with the increase of CO2 concentration, and the flame propagation speed decreases even more slowly. Meanwhile, the molar fraction of NO at chemical equilibrium decreases with the increase of CO2 concentration and the decrease is decreasing, which indicates that the effect of CO2 concentration in biogas on NO is simpler. While the molar fraction of NO2 does not change regularly with the change of CO2 concentration, the effect of CO2 concentration in biogas on NO2 is complicated. The highest molar fraction of NO2 was found at chemical equilibrium when the CO2 concentration was 33.6%, when the target was a typical low calorific value biogas.

Numerical investigation on combustion and NOx formation characteristics under deep-staging conditions within a cyclone barrel

Numerical investigation on combustion and NOx distribution characteristics of coal within a cyclone barrel under deep-staging conditions was conducted. Char conversion model and NOx formation model with refined NO heterogeneous reduction mechanism and oxidation rate of HCN suitable for cyclone barrel were implemented and validated with experimental data. The maximum deviations between the predicted and experimental values of NO and CO concentrations are 12.1% and 18.6% respectively under various stoichiometric ratios. Based on the refined models, the NO distribution in cyclone barrel under deep-staging condition is obtained. In the cyclone barrel, the concentration of NOx is higher in the primary-air-controlled and near-wall zones, which hinders further NOx reduction. The appropriately delayed secondary air supply can avoid the centralized supply of O2 and form a reducing atmosphere region in the primary-air-controlled zone, which greatly reduces the initial formation of NOx. In addition, the central zone of the cyclone barrel is the core region for NOx reduction. The area of the central zone with a strong reducing atmosphere can be significantly enlarged by increasing the velocity of secondary air. The NOx formation in cyclone barrel drops by 26.5% under deep-staging condition when the secondary air velocity increases from 20 m/s to 50 m/s. Finally, the oxygen-enriched and deep-staging technology is applied to the cyclone barrel. An ultra-low NOx formation in cyclone barrel is achieved. When the O2 concentration of secondary air increases from 0.21 to 0.40, the NOx formation drops by 64.1% under deep-staging condition. Moreover, the elevated flue gas temperature with O2 enriched in cyclone barrel makes it more suitable for the safe operation of slag tapping cyclone barrel.

NUMERICAL STUDY ON NOX EMISSION REDUCTION MECHANISM OF HCCI MARINE DIESEL ENGINE FOR IMO TIER III EMISSION LIMITS

With the advantages of ultra-low emissions of oxides of nitrogen (NOX) and high thermal efficiency, the homogeneous charge compression ignition (HCCI) mode applied to marine diesel engine is expected to be one of the technical solutions to meet the International Maritime Organization (IMO) MARPOL73/78 Convention-Annex VI Amendment Tier III requirement. According to the NOX chemical reaction mechanism, taking a marine diesel engine as the application object, the numerical study on the NOX formation characteristics of n-heptane for HCCI combustion process is performed. The results indicate that NO is usually the main component in the generation and emissions of NOX with the n-heptane HCCI mode. The combustor temperature plays more important role in the proportion of NO generation and emission. Compared with the experimental data of conventional marine diesel engine, the emission reduction rate of NOX can achieve an average of more than 95% in using HCCI technology.

Experimental study on NOx emission characteristics of Zhundong coal in cyclone furnace

Slag tapping cyclone furnace has drawn increasing attention due to its promising advantage in burning Zhundong coal safely, but is accompanied by high NOx emission. To develop low NOx combustion technology for cyclone furnace, the NOx formation characteristics of Zhundong coal in cyclone furnace were experimentally investigated in this study with a 100 kW cyclone combustion test bench. Results show that the key point of NOx reduction in cyclone furnace is to create a strong reducing atmosphere, which can be available in the central zone and lower part of cyclone barrel when the cyclone stoichiometric ratio (SR) is not greater than 0.8. When the cyclone SR drops from 1.1 to 0.8 and 0.7, NOx formations at the outlet of burnout furnace decrease by 41.8% and 54.9%, respectively. In addition, lowering primary air rate can remarkably reduce the initial formation of NOx because of an additional strong reducing atmosphere region created in the primary-air-controlled zone, where the volatile NOx can be remarkably inhibited. In cyclone barrel, the NOx formation is higher in the near-wall zone, which hinders the further NOx reduction. It is mainly attributed to the elevated O2 concentration in this region. To reduce NOx formation, the centralized air supply should be avoided to narrow the area with high concentration O2. The staging secondary air arranged in separating way is recommended.

Effect of biomass co‐firing position on combustion and NOX emission in a 300‐MWe coal‐fired tangential boiler

AbstractCo‐firing biomass in an existing coal combustion boiler is a promising way to mitigate carbon emission in the context of global carbon neutrality. This paper investigated the effect of biomass injection location on combustion and NOX formation characteristics in a 300‐MWe tangential boiler co‐firing with coal. Numerical models have been validated against experimental measurement for both pure coal firing and biomass/coal co‐firing cases. Compared to pure coal firing, co‐firing case with biomass injected into the highest layer can sustain a comparable temperature distribution profile along the furnace height, and generate a lower NO emission by around 20 ppm. By moving the biomass injection location downward, the temperature difference between co‐firing and pure coal firing cases becomes larger, and the final NO emission increases continually from 222 to 240 ppm. When biomass is injected through the lowest layer, N element in biomass volatile is oxidized to NO directly because of the abundant oxygen; thus, NO emission turns to be the highest among all co‐firing cases. Contrarily, when biomass is injected through the highest layer, the majority of N in biomass volatile is released as NH3, and it further acts as a reduction agent for NO, thus leading to the lowest NO emission.

Detailed measurements of in-furnace gas temperature and species concentration distribution regarding the primary-air distribution mode in a spreader and reversal chain-grate furnace

In order to uncover the coal combustion and NOx formation characteristics of chain-grate furnaces and evaluate the effect of the primary-air distribution mode, industrial-size tests with measurements taken of the overall gas temperature distribution in the furnace height direction and gas components (O2, CO, and NO) in the grate zone in a 35 t/h reversal chain-grate furnace were performed at four primary-air distribution modes of the uniform air mode, front-lean air mode, middle-concentrated air mode, and rear-enhanced air mode. Gas temperature decreased continuously in the furnace height direction while showed an increase-to-decrease trend as the grate proceeded. The high-temperature zones with levels below 1350 °C and a small suspension combustion share in the furnace height direction not only confirmed that the primary NOx formation relied on fuel-NO but also ruled against the availability of air staging along the furnace height for NOx reduction. The uniform air mode achieved the highest levels in both burnout and NOx emissions. The other three setups with a sharp air flux reduction in the former air box, decreased apparently NOx emissions while affected burnout to some extent. The rear-enhanced air mode delayed coal combustion with the largest extent and achieved the lowest NOx emissions but highest carbon in slag. In contrast, the middle-concentrated air mode relying on the highest air flux at the central air boxes for strengthening the primary combustion stage, resulted in both NOx emissions and carbon in slag showing acceptable levels of 493 mg/m3 (at 6% O2) and 9.27%, respectively. NOx emissions were reduced by about 18% and meanwhile carbon in slag raised only a limited extent in comparison to the conventional uniform air mode. Therefore, the middle-concentrated air mode was recommended as the optimal primary-air distribution pattern among the four setups.

Numerical Study of NOx Formation Characteristics on the 35 MW Staged Oxy-Coal Combustion

In this study, the NOx formation has been numerically investigated on a 35 MW large-pilot oxy-fuel combustion boiler by employing an improved gas phase reaction mechanism and radiation property models. The fuel is sub-bituminous coal. After verifying the prediction with experimental data, the in-furnace flow patterns, temperature distribution, and NOx formation characteristics are analyzed in detail in the conditions of air-fuel combustion, oxy-fuel and staged oxy-fuel combustion. The results show that aerodynamic and temperature field in staged oxy-fuel combustion are similar to those in air-fuel combustion, which ensures the smoothly transition and similar heat transform characteristics between oxy-fuel combustion and air-fuel combustion. Staged oxy-fuel combustion can effectively reduce the NOx formation. More precisely, fuel staged combustion and fuel-oxygen two-way staged combustion can reduce 16% and 22-30% NOx emission, respectively. With the increase of the equivalent ratio in the burner zone, the reduction of NO becomes more significant. The fuel-oxygen two-way staged combustion can effectively reduce NOx, and the maximum NOx reduction ratio can reach 30%, then, the NOx emission in this condition is 69% lower than that in air-fuel combustion. The results in this study could provide a reference for low NOx operation of oxy-fuel combustion.

Industrial Measurement of Combustion and NOx Formation Characteristics on a Low-Grade Coal-Fired 600MWe FW Down-Fired Boiler Retrofitted with Novel Low-Load Stable Combustion Technology

Industrial Measurement of Combustion and NOx Formation Characteristics on a Low-Grade Coal-Fired 600MWe FW Down-Fired Boiler Retrofitted with Novel Low-Load Stable Combustion Technology