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The need to reduce global carbon dioxide (CO2) emissions is driving the conversion of coal-fired power plants to use methane, which can reduce CO2 emissions by >40%. However, conducting gas firing in coal boilers changes the heat transfer profile; therefore, preliminary evaluations using computational fluid dynamics are required prior to conversion. Here, methane was used as a heat input source in the simulation of an existing coal boiler, and combustion, nitrogen oxides (NOx) emission characteristics, and heat transfer profile changes inside the boiler were analyzed. Furthermore, changes in the burner zone stoichiometric ratio (BZSR) were simulated to restore the decreased heat absorption of the furnace waterwall, revealing that air distribution could change the heat absorption of the waterwall and tube bundles. However, this change was smaller than that caused by conversion from coal to methane. Therefore, to implement gas firing in coal boilers, alternatives such as output derating, using an attemperator, or modifying heat transfer surfaces are necessary. Despite these limitations, a 70% reduction in NOx emissions was achieved at a BZSR of 0.76, compared with coal. As the BZSR contributes significantly to NOx emissions, conducting gas firing in existing coal boilers could significantly reduce NOx and CO2 emissions.

In this work, subair injection was proposed to improve the combustibility and NOx emission in a 500 MW tangentially fired coal boiler. The location of injection ports was determined based on the coal particle trajectory and its effect was investigated numerically. The flow rate of subair was set to 0, 5, and 10% of the total combustion air. The secondary air flow rate was decreased appropriately to ensure that the total quantity of combustion air remained constant. The over-fire air was not adjusted to retain the effect of an air-staged combustion. The simulation results showed that the subair improved the combustibility of coal particles originating from burners A and B in the lower part of the furnace. Particles from other burners were not affected significantly. In addition, this method achieved reduction of NOx by 6.3 and 13.2% when the subair accounted for 5 and 10% of the combustion air, respectively. This reduction was attributed to the decrease in the peak temperature as a result of a wider combustion region. The proposed subair technique improved the coal combustibility and reduced the NOx emissions successfully in the furnace.

Pulverized Coal Injection (PCI) is one of the most effective technologies for reducing coke consumption in blast furnaces. Its main role is as the heating source and for the generation of CO gas. Generally, PCI coal is a high-rank coal, but steel mill companies are attempting to use low-rank coal as an energy source in PCI combustion blast furnaces because of the increasing cost of high-rank coal and decreasing reserves. The purpose of this investigation was to determine how the coal rank is correlated to the pulverized coal particle temperature and CO emission. This study was performed using a Laminar Flow Reactor (LFR), which represents the combustion environment of pulverized coal inside a blast furnace. Since the PCI system was developed for iron making, the combustion characteristics of pulverized coal are important in the iron and steel industries. According to the different types of coals, the coal flame structure, coal particle temperature, and exhaust gases (CO and CO 2 ) were investigated. This study demonstrated that the combustion characteristics of coal were influenced by several properties of individual coals. Primarily, the coal particle temperature and CO emission were found to have the strongest influence on the combustion characteristics of these coals. Moreover, the fragmentation phenomenon occurring in some coals was also an important factor influencing the PCI combustion characteristics. Therefore, this study significantly considered the coal properties, focusing on images of the burning coal particle flames, the particle temperature, and the CO/CO 2 emissions.

Recently, much research has been put into finding the causes and solutions of slagging/fouling problems that occur at the end of the boiler. This slagging/fouling, caused by low-rank coal`s ash, disturbs the thermal power and greatly reduces efficiency. In environmental aspects, such as NOx pollution, governments have been implementing restrictions on the quantity of emission gases that can be released into the atmosphere. To solve these problems, research on Ash Free Coal (AFC), which eliminates ash from low-rank coal, is in progress. AFC has advantages over similar high-rank coals because it increases the heating value of the low grade coal, reduces the contaminants that are emitted, and decreases slagging/fouling problems. In this study, using a DTF, the changes of NOx emissions, unburned carbon, and the characteristics of ash deposition were identified. KCH raw coal, AFC extracted from KCH, residue coal, Glencore, and Mixed Coal (Glencore 85wt% and residue coal 15wt%) were studied. Results showed that AFC had a significantly lower emission of NOx compared to that of the raw coal and residue coal. Also, the residue coal showed a higher reactivity compared to raw coal. And finally, In the case of the residue coal and mixed coal, they showed a lower ash deposition than that of low-rank coal.

After a reheating furnace installation, the modification of the size and the heat capacity is very difficult. Therefore, the development of design package tool is required for the computation on the correct specifications before the design and the installation. Prior to development of the design tool, a module that calculates the amount of heat loss of each part according to the specifications for determining the thermal efficiency of a continuous heating furnace was developed and applied to the oxy-fuel industrial furnace. Through this, the effects of fuel type, oxygen fraction and recirculation on the efficiency of the furnace of which the output is 110Ton/hour were analyzed. In oxy-fuel combustion condition, the efficiency was 15% higher than air combustion conditions. With the using COG(Coke Oven Gas) instead of LNG, the efficiency was slightly increased. In the air combustion condition, the efficiency was increased about 33% with the preheated air. But, in oxy-fuel condition, the amount of exhaust gas was reduced, so the efficiency was increased about 7%.

The NOx correlation for fuel staged combustion on CH4/air flames was investigated as a function of operating conditions such as pressure, flame temperature, fuel-to-air ratio, and fuel staging ratio. Firstly, the flow characteristics for fuel staged combustion were investigated using particle image velocimetry (PIV) under atmospheric conditions, through which fuel and air mixing was correlated with the turbulence intensity. The turbulent intensity near the burner outlet was strong when the fuel staging ratio (α) was 3%, which provided better fuel and air mixing. NOx correlation for fuel staged combustion was investigated using a lab-scale gas turbine combustor at high pressure. In particular, NOx emissions scale with pressure (NOx = Pn) with n = 0.5 under premix combustion and n = 1.1 for fuel staged combustion. A new NOx correlation for fuel staged combustion is suggested in the form of NO x = a · e ( b · T fl + d · α ) · P n · far c under the operating conditions of real gas turbines.

Numerical study was investigated to obtain the database for developing a fast pyrolysis power boiler by waste fuel. The studies with various conditions were performed using ANSYS FLUENT. Also, the fuel properties was experimentally analyzed to utilize the input parameters for numerical analysis, that were proximate and ultimate analysis, reaction kinetics included pyrolysis and combustion. The results showed that temperature, combustion and exhausted gases was changed with heating value of fuel and feeding rate. Finally, the stable operating condition by analyzing results was proposed.

The critical current density and flux pinning properties of the Ba0.55K0.45Fe2As2 high-T c superconductor with T c = 37 K are studied using the field and the time dependences of the magnetization. The temperature dependence of the critical current density J c (T) has been found to follow the form J c ∝ (1−T/T c ) n and is consistent with δT c -type pinning due to randomly-distributed defects that are larger than the coherence length ξ. The temperature dependence of the magnetic relaxation rate S exhibits a peak at a much lower temperature, which corresponds to a smaller pinning energy in the Ba0.55K0.45Fe2As2 superconductor. Moreover, the effective pinning potential U o increases with increasing temperature and this behavior is in agreement with those of high-T c cuprate superconductors.

Background The whistle deformity is one of the common sequelae of secondary cleft lip deformities. Santos reported using a crossed-denuded flap for primary cleft lip repair to prevent a vermilion notching. The authors modified this technique to correct the whistle deformity, calling their version the cross-muscle flap. Methods From May 2005 to January 2011, 14 secondary unilateral cleft lip patients were treated. All suffered from a whistle deformity, which is characterized by the deficiency of the central tubercle, notching in the upper lip, and bulging on the lateral segment. The mean age of the patients was 13.8 years and the mean follow-up period was 21.8 weeks. After elevation from the lateral vermilion and medial tubercle, two muscle flaps were crossed and turned over. The authors measured the three vertical heights and compared the two height ratios before and after surgery for evaluation of the postoperative results. Results None of the patients had any notable complications and the whistle deformity was corrected in all cases. The vertical height ratios at the midline on the upper lip and the affected Cupid's bow point were increased (P Conclusions A cross muscle flap is simple and it leaves a minimal scar on the lip. We were able to reconstruct the whistle deformity in secondary unilateral cleft lip patients with a single state procedure using a cross-muscle flap.