Sharp Rise In Temperature Research Articles

Critical conditions for laser initiation of a chemical reaction in thin layer placed on substrate

In this work, we propose a model for the laser initiation of a chemical reaction in a film supported by an inert substrate. Materials of the film and the substrate have different thermal and physical properties. The model includes the equations of heat conductivity and chemical kinetics of the overall reaction. The reaction rate depends on the reactant concentration by power law and on the temperature by Arrhenius law. Consideration is given to possible changes in optical properties of the film due to accumulation of reaction products as well as to features of laser absorption and reflection from the film-substrate interface. For a detailed numerical study, the model is presented in dimensionless variables selected by fitting spatial and temporal scales that characterize the model. This reduces the number of variable parameters and gives the most general results. Critical conditions are found between different modes of the process. At the subcritical pulse duration, either no chemical reaction takes place or a reaction stops immediately after it started. At the supercritical pulse duration, complete conversion occurs in the laser hot spot. It is found that the dependence of optical properties of the film on the degree of conversion strongly affects the temperature, conversion dynamics, size of the reaction product zone, and critical conditions. In this work, for the first time, the dependence of the critical conditions separating different modes of process development (sharp temperature rise with complete transformation in the center of the heating spot and extinction, which may be accompanied by partial transformation) on model parameters was investigated. For the first time, the dynamics of the reaction front in the film located on the substrate was analyzed for conditions of changing optical properties. The results of calculations can be useful in discussing the mechanisms of destruction of polymer coatings, in describing methods of protection against external influences, as well as in developing methods for modifying surface structures, creating three-dimensional objects with specified properties, synthesis of intermetallic products in 3D - technologies, etc.

Critical thickness of nano-enhanced RT-42 paraffin based battery thermal management system for electric vehicles: A numerical study

Use of electric vehicles has increased worldwide. Lithium Ion (Li-Ion) batteries are widely used to power them due to their high energy density and low self-discharge rates as compared to other conventional batteries such as lead acid. But at 3C discharge rates (where 3C means 3 times the rated Ah capacity of the battery cell), there is a sharp rise in temperature which impacts battery cell performance. After temperature exceeding 50 °C, the Li-Ion battery cells become unstable and catch fire and thus, its thermal management became a priority. Battery thermal management system (BTMS) aims to control battery cell temperature within operating limits at high discharge rates and ambient temperatures. BTMS utilizes either a fluid medium to carry away heat or working material in the form of Phase Change Material (PCM). In the present numerical investigation RT-42 paraffin is used as working material to control battery temperatures. In this investigation the performance of RT-42 paraffin for different thicknesses ranging from 1 mm to 7 mm around the battery cell was used to control battery temperature effectively. It is observed that up to 4 mm thickness of RT-42 paraffin gain in controlling the temperature is maximum. But low thermal conductivity of pure RT-42 impacts on its heat transfer performance. Therefore investigation of performance of Al2O3/RT-42 paraffin nano PCM (NePCM) with percentage weight fractions of 0.5, 1, 2, and 5 at critical thickness 4 mm was carried out. NePCM was able to maintain the maximum battery temperature 42.77 °C and remains in partially liquefied state at the end of discharge cycle of 1200 s.

Future climate change and impacts on water resources in the Upper Blue Nile basin

Abstract This study aims to assess the impact of climate change on the water resources of the Upper Blue Nile basin using an integrated climate and hydrological model. The impact of climate change on water resources is being assessed using the regional climate model (RCM) under the representative concentration pathway (RCP4.5 and RCP8.5) scenarios and the Soil and Water Assessment Tool (SWAT) hydrological model. Future climate scenarios have been developed for the 2030s (2021–2040) and the 2050s (2041–2060). The study found that the projected rainfall shows a decreasing trend and is not statistically significant, while the temperature shows an increasing trend and is statistically significant. Due to the sharp rise in temperature, the annual evapotranspiration increased by about 10.4%. This and the declining trend of rainfall will reduce streamflow up to 54%, surface runoff up to 31%, and water yield up to 31%. Climate change causes seasonal and annual fluctuations in the water balance components. However, the projected seasonal changes are much greater than the annual changes. Therefore, the results of this study will be useful to basin planners, policymakers, and water resources managers in developing adaptation strategies to offset the adverse effects of climate change in the Upper Blue Nile basin.

Gas-Phase Nucleation of Diamond Clusters upon a Sharp Rise in Temperature under Conditions of CVD Synthesis

It is shown that the predominant nucleation of diamond nuclei (instead of graphite ones) in plasma or hot-filament assisted CVD technology is due to a sharp increase in the temperature of the region of the initial gas mixture’s motion. The nucleation of diamond nuclei then occurs immediately in the gas phase. The reason for such predominant nucleation is high oversaturation by small hydrocarbon fragments in the gas mixture, due to a rapid change in temperature and substantial differences between the desorption of such fragments from the surfaces of nuclei and the oxidation of nuclei. A way is described of synthesizing massive diamonds without the use of high pressures and CVD technology in its traditional form.

Introducing SiC/C dual-interface on porous silicon anode by a conventional exothermic displacement reaction for improved cycle performance

The poor cyclability and high cost are the two major obstacles to the commercial applications of Si-based anode materials. Porous structure and carbon coating may facilitate the ion and electron conduction and also restrict the huge volume change of Si anodes. In addition, introducing a ceramic interlayer between Si and C can reduce the chemical reaction of Si with fluorine ions in the electrolyte and hence improve the cyclability. In this work, porous Si anode protected by SiC/C dual-interface is prepared by simply heating fine Mg 2 Si particles in pure CO 2 at 650 °C, based on the conventional exothermic displacement reaction between Mg (released from Mg 2 Si) and CO 2 . The large amount of heat generated during the displacement reaction leads to sharp temperature rise, resulting in the formation of SiC at such a low temperature. The porous Si/SiC/C powders as well as the spherical sample prepared by subsequent spray-drying and pyrolysis process display much improved rate capability and cyclability as compared to the porous Si/C counterpart, due to the enhanced structural integrity induced synergistically by the porous structure, SiC/C dual-interface and spherical structure during the repeated lithiation/delithiation cycles. • SiC/C dual-interface is introduced on porous Si anode at low temperature. • Fine Mg 2 Si leads to high exothermic displacement reaction between Mg and CO 2 . • Porous SiC/C/Si anode exhibits improved rate capability and cyclstability. • Spherical porous SiC/C/Si anode shows the least volume expansion after cycles.

Numerical Simulation Study on the Air/Water Counter- current Flow Limitation in Nuclear Reactors

After a loss-of-coolant accident (LOCA) in a Pressurized Water Reactor (PWR), the temperature of the fuel elements cladding increases dramatically due to the heat produced by the fission products decay, which is not adequately removed by the vapor contained in the core. In order to avoid this sharp rise in temperature and consequent melting of the core, the Emergency Core Cooling System is activated. This system initially injects borated water from accumulator tanks of the reactor through the inlet pipe (cold leg) and the outlet pipe (hot leg), or through the cold leg only, depending on the plant manufacturer. Some manufacturers add to this, direct injection into the upper plenum of the reactor. The penetration of water into the reactor core is a complex thermofluidodynamic process because it involves the mixing of water with the vapor contained in the reactor, added to that generated in the contact of the water with the still hot surfaces in various geometries. In some critical locations, the vapor flowing in the opposite direction of the water can control the penetration of this into the core. This phenomenon is known as Countercurrent Flow Limitation (CCFL) or Flooding, and it are characterized by the control that a gas exerts in the liquid flow in the opposite direction. This work presents a proposal to use a CFD to simulate the CCFL phenomenon. Numerical computing can provide important information and data that is difficult or expensive to measure or test experimentally. Given the importance of computational science today, it can be considered a third and independent branch of science on an equal footing with the theoretical and experimental sciences.

The final «battle» of the great commander

Alexander the Great is considered to be one of the greatest commanders in history, who was able to create a world empire due to successful conquests during his lifetime. The circumstances of his death remain the subject of scientific discussion in the historical and medical community. This article briefly lists the possible causes of the statesman’s death. It is reliably known that in the last year of his life, Alexander the Great was under the influence of a fatal prophecy about his own demise, was angry, systematically abusing alcohol and overeating during lush feasts. Such historians as Aristobulus, Hares, Plutarch tried to justify the king’s bad habits with his love for feast talks and «body heat». Alexander the Great died in June 323 BC, but experts still find it difficult to give an unambiguous answer to the question about the cause of his death. At different times, numerous hypotheses were put forward, such as: liver disease, malaria, pneumonia, poisoning (possibly a plant called white hellebore), snake bite, typhoid fever, Guillain‑Barrе syndrome, etc. Studies of the 1990s with an analysis of symptoms made it possible to exclude versions of malaria, pneumonia, typhoid fever, and West Nile fever. According to Greek scholars, the most plausible version of Alexander the Great’s disease is pancreatic necrosis, caused by the king’s addiction to «heavy» food and alcohol. According to the ruler’s contemporaries, the onset of symptoms was characterized by severe abdominal pain after «heavy» food and wine, accompanied by fever and daily progressive worsening during 14 days. Doctors used artificial induction of vomiting and cold baths, but Alexander the Great, despite his poor health condition, continued overeating and drinking wine. This caused a sharp temperature rise, increased sweating and febrile chill, as well as difficulty of breathing. Before death, Alexander was tormented by severe abdominal pain. He died in Babylon at the age of 33 from sepsis. His body was embalmed and placed in a sarcophagus.

Analysis of Chemical Reaction Process after Pentaerythritol Tetranitrate Hot Spot Ignition.

In this paper, ReaxFF force field combined with molecular dynamics method was used to study the ignition, deflagration, and detonation of pentaerythritol tetranitrate (PETN) induced by hot spots. The hot spot is 5.6% of the total volume. When the hot spot temperature is 1000 K, the deflagration and detonation of PETN cannot be observed in the simulation time of 200 ps. When the hot spot temperature is 2000 K, it corresponds to the heating time of 20 to 50 ps, deflation and detonation were observed. During hot spot ignition, the products of decomposition of the condensed phase PETN are dominated by NO2 and HONO. The energy required for the C–C bond and C–ONO2 bond cleavage in PETN is high, resulting in only a small amount of CH2O and NO3 during the reaction. Small nitrogen-containing molecules (such as NO2, NO3, HONO, HNO3, etc.) mainly exist during thermal equilibrium, while the number of N2 increases sharply during the thermal runaway stage, and a small amount of NH3 and NH2 are also produced. H2O molecules are formed before CO2 and N2 are produced, and the number always dominates. During the thermal runaway, the entire system can maintain a spontaneous reaction, resulting in a sharp rise in temperature of about 2500 K in 20 ps. During this phase, the catalytic effect of H2O accelerates the formation of CO2 and N2 due to the near Chapman–Jouguet point in the crystal. PETN is a weak oxygen balance explosive that results in a small amount of CO and H2 production during the thermal instability phase. When the reaction is balanced, the relative molecular mass is close to or exceeds that of PETN. The product is only less than 1% of the total mass fraction, while the small molecule product is as high as 78%, and some relative molecular masses are [75,225]. The intermediates account for about 21%. Rapid and complex reaction events make it difficult to accurately predict the structure of these intermediates by existing experiments and calculations, which will be the focus of future research.

Thermal damage and fatigue estimation in heavily loaded lubricated rolling/sliding contacts with Micro-Geometry

A previously developed model for heavily loaded Elastohydrodynamically lubricated (EHL) contacts with surface micro-geometry for the calculation of surface distress (micropitting), based on high-cycle fatigue and mild wear competition, is herewith further extended. It now includes the effects of frictional heating with a sharp temperature rise developed in the rolling contact. For this, a new surface damage model, originated in creep modelling, is included. With this modification, the detrimental effect of high temperature developed in the rolling/sliding contact can now be accounted for. This model can consider sharp or moderate surface temperature rise during over-rolling is found in bearings and gears operating at high speeds or under the combination of speeds, loads and unfavourable environmental aspects. The present model introduces a threshold limit made of the combination of temperature and (heating time under stress) load cycles above which the conditions in the rolling contact are deemed damaging for the steel microstructure and the tribological functionality of the rolling contact. The surface damage model is first compared with laboratory experiments in rolling/sliding conditions and then applied to study combinations of loads, sliding speeds and the effect in rolling bearings. The ability of the present model to include damaging mechanisms, other than classical metal fatigue, increases the flexibility in contact surface damage modelling and allows for the accounting of phenomena up to now excluded from better estimation of the machine elements surface life.

Oxidation of HfB2-SiC-Ta4HfC5 ceramic material by a supersonic flow of dissociated air

The oxidation of an ultra-high-temperature ceramic material (HfB2-30 vol%SiC)-10 vol%Ta4HfC5 produced by reactive hot pressing at a temperature of 1800°C (pressure 30 MPa, holding time 30 min, Ar) under long-term exposure (2000s) to a supersonic flow of dissociated air was studied. It was found that the sample surface temperature, set during heating and oxidation on a high-frequency induction plasmotron, was significantly lower than for samples unmodified with super-refractory tantalum-hafnium carbide Ta4HfC5. It was also found that under similar exposure conditions there was no sharp temperature rise to 2500−2700°C – the temperature did not exceed 1850°C. Features of the oxidised material surface microstructure were noted, in particular, the existing gradient in the elemental composition and morphology of the oxide particles forming the surface. It was found that the main crystalline oxidation product was a complex hafnium-tantalum oxide Hf6Ta2O17, which had a phase stability up to temperatures of ∼2250°C, which set it apart from individual hafnium oxide.

A model for rolling bearing life with surface and subsurface survival: Surface thermal effects

A previously developed model for bearing life calculation, based on high-cycle fatigue, including the separation of the surface and the subsurface survival of the rolling contact, is herewith further extended. It now includes the effects of frictional heating with a sharp temperature rise developed in the rolling contact. For this, a new surface damage integral, based on the creep mechanism, is included in the model. With this modification, the detrimental effect of high temperature developed in the rolling contact can now be accounted for. Sharp surface temperature rise during over-rolling are found in bearings operating at high speeds or under the combination of speeds, loads and unfavourable environmental temperatures. The present model introduces a threshold limit value of temperature above which the temperature in the rolling contact is deemed damaging for the steel microstructure and the tribological functionality of the rolling contact. The surface creep-damage model is first calibrated with endurance tests of bearings and then applied to study combinations of loads and speeds and the effect of the steel thermal conductivity on the life expectancy of the bearing. The ability of the present model to include damaging mechanisms, other than classical metal fatigue, increases the flexibility in bearing life predictions and allows to account for phenomena hitherto excluded from the estimation of the bearing fatigue life.

Vibration reduction design of extension housing for printed circuit board based on particle damping materials

When a high-speed moving object is subjected to high-intensity vibration shocks and a sharp rise in temperature, the internal electronic components (Printed Circuit Board) will produce a serious dynamic response. In order to meet the needs of future product development, a new structure design of vibration reduction of extension housing for PCB is proposed. Firstly, dynamic analysis of the extension system is performed to determine the modal sensitive area. The installation position of the damper is determined by combining the sensitive area of vibration transfer path of the extension system. Then the discrete element method is used to calculate the energy consumption of the particle system. For the design of particle damper model, the parameters such as particle size and filling rate are optimized, and the optimal damper installation scheme is determined. Finally, by combining with the experiment, the optimal configuration of particle damper parameters is explored, and the damping effect in the sensitive area of vibration transfer path can reach 57.90%. Under the combined installation scheme, the vibration reduction effect can reach 60.62% in the main vibration direction. This method is completely applicable to the harsh environment of temperature rise and it is of great significance for improving the anti-vibration characteristics of the PCB.

Modelling and simulation of industrial trickle bed reactor hydrotreating for whole fraction low-temperature coal tar simultaneous hydrodesulfurisation and hydrodenitrification

Whole fraction low-temperature coal tar (LTCT) has a high content of heavy compounds, direct entry into an industrial reactor for hydrotreating (HDT) conversion into fuel oil is a new technology that has not been widely reported. Furthermore, a copious amount of heat is generated, resulting in hot spots and temperature flying on the catalyst bed.This study uses the gPROMS software, based on the kinetic parameters which are determined from several HDT reactions using experimental data in small-scale TBR, combined with energy balance and mass transfer equations among three phases to construct industrial TBR model with a treatment capacity of 250,000 tons/year. This model was used for simultaneous HDS and HDN process simulation.The Simulation results show that the sharp temperature rise along the catalyst bed length can arrive at 70 K without quenching, which is obviously higher than that of petroleum distillate hydrogenation. So, a optimal bed configuration of equal bed lengths and unequal bed inlet temperature was established by simulating and optimizing the reactor. with each bed 350 cm in length and inlet temperatures of 633 K, 643 K, 653 K, and 653 K, respectively, it has a reasonable temperature rise distribution, lower added hydrogen quench amount of 47360.65 Nm3/h, while sulfur and nitrogen removal rates can reach 87.55% and 86.46%, showing better performance than that of a small scale reactor. Hydrogen quenching not only lowers the temperature of the mixture and replenishes the chemical hydrogen consumption but also facilitates the removal of S, N heteroatom compounds. The results can provide a guidance for bed configuration for whole fraction LTCT industrial hydrogenation devices.

Проблемні питання теплогідравлічного розрахунку активних зон перспективних водоохолоджуваних реакторів з надкритичними параметрами

The fundamental thermophysical features of the heat exchange process between the heated wall of a vertical channel and the light-water coolant of supercritical parameters concerning the conditions of heat-generating assemblies channels and cores of perspective energy nuclear reactors are considered. The available methods and recommendations for determining the limits of thermal load are analyzed. It is a guarantee the absence of the characteristic dangerous mode possibility of deteriorated heat exchange in these conditions and corresponding sharp rise in the channels wall temperature, which threatens their destruction. The physical nature of the occurrence of degraded heat transfer regimes remains unclear, and the existing approaches to the implementation of thermohydraulic calculation in such conditions are not sufficiently justified. The complex nature of intercellular heat and mass transfer in the fuel assembly and the presence of individual thermohydraulic cells with reduced levels of heat transfer intensity indicate that the existing method of determining the area of degraded heat transfer in the reactor core channels with supercritical parameters of the coolant is significantly simplified. Insufficient data and research results have been revealed to create adequate methods of heat-hydraulic calculation, suitable for taking into account the peculiarities of the heat transfer process complex flow under conditions of supercritical parameters of the coolant. The application of such methods should be the basis for ensuring the safe operation of prospective reactors and minimizing potential losses of a different nature from accidents caused by the destruction of cores through unacceptable heat transfer modes. To this end, the main direction of further research is identified.

The effects of subsonic and supersonic dissociated air flow on the surface of ultra-high-temperature HfB2-30 vol% SiC ceramics obtained using the sol-gel method

By hot pressing (1900 °C, 30 MPa, holding time 15 min) of HfB2-(SiO2-C) composite powder, an ultra-high-temperature ceramic material of HfB2-30 vol% SiC composition with nanocrystalline silicon carbide has been obtained. The effects of subsonic and supersonic dissociated air flow on the surface of produced materials have been studied on a high-frequency induction plasmatron in the geometry of a cylindrical sample with a flat face, fixed in a copper water-cooled holder with a 1 mm protrusion. It has been shown that a sudden rise in the average surface temperature of the samples to ∼2600 °C is characteristic for both modes, which is associated with the occurrence of local sites with a temperature >2000 °C and a subsequent increase in their area. It is a matter of evaporation of the borosilicate glass layer from the surface of the oxidized sample and formation of the ceramic layer of a highly catalytic and low thermal conductive porous HfO2 layer, which is confirmed by the emission spectroscopy data, XRD and elemental analysis of the material surface after the experiments. The features of heating the oxidized surface of the samples under the impact of subsonic and supersonic dissociated air flow have been noted: there are differences in the location of overheated sites, initiating a sharp temperature rise and the rate of growth of their area.

Thermomechanical Characterization and Modeling of Cold-Drawing of Poly(ethylene Terephthalate).

The tensile testing of amorphous polyethylene terephthalate is observed until failure by IR thermography and optical strain measurement. The deformation can be subdivided in six deformation phases: elastic deformation, neck formation with a localized sharp temperature rise, neck propagation, which is also known as cold-drawing, with heat generation in a transition zone, crack initialization with local heating, crack growth, and rupture. These deformation phases are showing different mechanical and thermal reactions to the deformation. The initial and drawn samples are studied with differential scanning calorimetry. Alongside heating due to the dissipation of mechanical energy, latent heat due to strain-induced crystallization was detected. While the material is cold-drawn, a high dependence on the crosshead speed is found for the heat generation as well as the draw ratio, mechanical response, and morphological changes due to orientation and crystallization. For cold-drawing, a thermomechanical model is introduced, which is based on the first law of thermodynamics and reproduces the temperature distribution along the sample.

Daytime and nighttime heat wave characteristics based on multiple indices over the China–Pakistan economic corridor

The sharp rise in temperature has increased the frequency, intensity, duration, and timing of heat waves (HWs) over different regions of the world. Due to climate change, the China–Pakistan Economic Corridor (CPEC) is one of the highly vulnerable regions to HWs and needs comprehensive research studies to investigate the HW phenomenon in the region. This study analyzed the spatial and temporal changes in the daytime and nighttime HW characteristics based on multiple indices over the CPEC region. We used daily maximum and minimum temperatures (hereafter Tmax and Tmin) of 48 meteorological stations for the time period of 1980–2016. The non-parametric modified Mann–Kendall, Theil–Sen’s test, least square method, student t-test, and chi-square goodness-of-fit test techniques were used to analyze the long-term spatiotemporal changes in the daytime and nighttime HW characteristics. The results of the study show that the number of annual daytime/nighttime HW events, annual sum of participating daytime/nighttime HW days, the average length of annual daytime/nighttime HW events, duration of the longest annual daytime/nighttime HW event, the average magnitude of all annual daytime/nighttime HW events, amplitude of the hottest annual daytime/nighttime HW event, and the ending date of annual last daytime/nighttime HW event exhibited significant increasing trends at the rate of 0.78/1.43 events decade−1, 10/11.82, 2/1.74, 2.16/1.52 days decade−1, 0.40/0.59, 0.24/0.73 °C decade−1, and 12.29/10 days decade−1, respectively. Despite all, the onset date of the annual first daytime/nighttime HW event has shown a significant decreasing trend of − 5.71/− 5 days decade−1. The obvious positive trend of HW behaviors indicates that the country has experienced more frequent, stronger, more intense, and longer HWs during the study period. The spatial pattern of the trend indicates that the southern, central and eastern parts of Pakistan exhibited prominent and consistent HW activities, while the northwestern mountainous regions showed high spatial variability with some stations exhibited decreasing trends in HW indices. The findings of this study will be a base for the projection and mitigation of HWs in the region. Based on the study findings, we recommend that the mechanism of HW and its natural and anthropogenic drivers should be thoroughly investigated over the study region.

Pure H2 production by methane oxy-reforming over Rh-Mg-Al hydrotalcite-derived catalysts coupled with a Pd membrane

Rh-Mg-Al hydrotalcites were synthesized by coprecipitation, then calcined and reduced to obtain catalysts active in the oxy-reforming of methane. In particular, it was shown that an increased activity can be obtained by reducing the Mg/Al ratio or increasing the Rh amount. In addition, the influence of pellet dimension and catalyst amount at same contact time was demonstrated to be negligible thanks to the characteristics of oxy-reforming which allows to work at low contact times without a sharp temperature rise. Moreover, a newly developed thermal treatment of the synthesized hydrotalcite was able to provide an active catalyst with an increased amount of reduced Rh over its surface, which provided very good performances. Finally, a hydrogen-selective Pd-membrane was integrated after the oxy-reforming and was able to separate H2 from the outlet mixture providing pure hydrogen in different conditions with high recoveries.

Climate Effects on Firn Permeability Are Preserved Within a Firn Column

AbstractWe have investigated the impacts of short‐term climatic events on firn‐permeability evolution, by analyzing density and permeability measurements from the NEEM 2009 S2 firn core from the North Greenland Eemian Ice Drilling (NEEM) site in Greenland. Our results indicate that the firn layers from 27.4 to 34.9‐m depth display the expected density but unexpected permeability values, indicating a change in firn permeability during the years 1917 to 1940. The δ18O and accumulation rates from a compilation of NEEM shallow cores indicate that 1928, 1929, and 1933 were significantly warmer years, and that 1928 and 1933 also had significantly higher accumulation rates. These results suggest that the sharp rise in Arctic temperature during the late 1920s and early 1930s caused metamorphism of the near‐surface firn, which was preserved in the layers at depth. Conversely, the average density remained undisturbed throughout this warm period. Our results show that climate fluctuations, especially increased temperature, permanently change the firn permeability. Without taking these changes into consideration, estimates of Δage will be inaccurate.

Study on the influence of low nitrogen combustion on boiler operation

With the national emphasis on improving the quality of atmospheric environment and protecting the ecological environment, the standards for pollutant emission from power station boilers are becoming more and more strict. In response to national environmental requirements, low nitrogen combustion technology has been adopted in coal-fired power plants. However, the introduction of low nitrogen combustion technology has also brought a series of negative effects on boiler operation. It not only includes a dramatic rise in the high ash carbon content and heating water flow, slow load response rate and such influence on the unit economy, but also includes great reduction of reheat steam temperature under low load, rapid sharp rise of load steam temperature. The steam temperature decreases when load decreasing rate greatly reduces, the effects, such as big deviation between steam temperature and wall temperature, slagging furnace, high water wall, temperature corrosion and so on, have an impact on the stability of the security unit. This paper investigates 13 coal-fired power plants with capacity of 300 MW to 600 MW in Inner Mongolia autonomous region, to study the effects of low nitrogen combustion of boiler operation, pointing out the necessity of reasonable control of the export of nitrogen oxide content.