Renewable energy has a significant role to play in helping the world achieve the greenhouse gas emission reduction necessary to achieve the pathway to a 2°C increase in global temperature. Electricity generation from wind and solar resources can contribute immensely to the decarbonization of power generation, but these resources are intermittent. High penetration of intermittent renewable power generation can cause grid stability and control issues for network operators, with fast response fossil fuel power plant necessary to provide security of supply and maintain grid stability. Increasingly natural gas-fueled distributed power generation is being installed to provide the necessary grid support. However, hybrid power plants comprised of a fossil fuel power generating system, a renewable power generation system and energy storage can provide both the low CO 2 electricity required to meet environmental constraints, and the despatchability and stability required by grid operators. Integrated Solar Combined Cycle Power Plants (ISCCs), comprising a Concentrated Solar Power plant and a natural gas fired combined cycle plant, have the potential to simultaneously reduce fossil fuel consumption, provide secure, highly predictable electricity generation, and reduce the cost of integrating renewable energy into a power system. While a number of ISCCs have been built at a larger scale (above 150MW power output), the concept has rarely been adopted for smaller scale distributed power applications. In addition, the traditional ISCC concept uses a steam bottoming cycle, which consumes water, and often locations where distributed ISCC could be utilized suffer from a scarcity of fresh water. This paper evaluates whether replacing the steam bottoming cycle with an Organic Rankine Cycle (ORC) alternative can provide a simpler, lower cost distributed ISCC solution that can be utilized on smaller and island grid systems, or mini- and micro-grids, to provide an affordable, water-free, low carbon power generation system.

Testing was performed on commercially available 1 kW spark ignition generators that were modified to operate on JP-8 and other heavy fuels. This approach is motivated by the US Military mandate that only one fuel, JP-8, be taken to the battlefield, and the increased electrical demands at the squad and platoon level. Small units require a portable power source that can meet their energy demands, particularly battery charging. While diesel engines can operate on JP-8, their weight limits their mobility at the platoon level. Spark ignition engines have better power density at the 1 kW level, but must be modified to burn logistically available fuel. Multiple approaches have been pursued to enable these engines to operate on JP-8. In the present study, the longer term effects of three approaches are examined and compared to an unmodified spark ignition generator operating on gasoline. These approaches include A) chemically altering the fuel as it flows to the engine to create a higher octane mixture, B) modifying the carburetor and using ether starter fluid to preheat the cylinder, and C) electrically heating the cylinder while modifying the fuel system for direct injection. The different generators were characterized by oil sampling at 15 hour intervals. Oil testing included flash point, viscosity, wear elements, and additives. Oil quality and emissions vary with load. Different approaches to conversion perform better at different loads. It was determined that multiple start-stop cycles with no load resulted in fuel dilution of the lubricating oil in several of the modified engines. Response varied with some of the modified engines maintaining low fuel dilution similar to the gasoline fueled engine while others indicated 15–20% fuel in the oil. During operation at full load, the modified JP-8 burning generators showed 3–5% fuel dilution in the oil while the unmodified gasoline generator was less than 1%. These experiments illustrate the challenges in developing portable, reliable JP-8 burning power sources. While further research and development is needed in each approach, it was shown that converted spark ignition engines are a promising path to portable logistic power. Oil analysis was shown to identify future research and development efforts to improve this technology.

Urban solid waste generation has drastically grown around the world, requiring creative, ecologically correct and sustainable solutions to be developed. This work considers a problem of thermodynamic optimization of extracting the most energy from a stream of hot exhaust produced by urban solid waste incineration, considering a stoichiometric combustion model, when the contact heat transfer area is fixed. For that, a mathematical model is introduced to evaluate the rate of heat generation due to the waste incineration process, and the exergetic (power) rate captured by a heat recovery steam generator (heat exchanger). The numerical results show that when the (cold) receiving stream boils in the counterflow heat exchanger; the thermodynamic optimization consists of locating the optimal capacity rate of the cold current. At the optimum, the cold side of the heat transfer surface is divided into three sections: preheating of liquid, boiling and superheating of steam. Experimental results are in good qualitative and quantitative agreement with the numerically calculated mathematical model results. Microalgae cultivated in large-scale vertical tubular compact photobiorreactors are investigated to treat the emissions produced by the incineration, and to increase the efficiency of the global system via cogeneration of co-products with high aggregated commercial value.

Thermoacoustic technology potentially offers a sustainable and reliable solution to help address the continuing demand for electric power. Thermoacoustic devices, operating on the principle of standing or traveling acoustic waves, can be designed as a heat pump or a prime mover system. This technical strategy is environmentally friendly as it utilizes noble gases, or air, as the working fluid and does not directly produce harmful emissions. However, heating and cooling sources are required to create the required thermal gradient. Due to the inherit simplicity and limitation of moving components, thermoacoustic devices require little maintenance and have a forecasted long operational lifespan. This paper will present the design considerations necessary to construct a traveling wave thermoacoustic heat engine. The modeling, analysis, fabrication, and testing with integrated sensors will be discussed to offer insight into the capabilities and subtleties. A case study with system operation at 54 Hz and 7.8% thermal to acoustic efficiency will be presented.

Development of alternative, clean and renewable energy production from different hydrocarbon materials helps to partially replace the limited resources of fossil fuels and also help reduce carbon emissions from fossil fuels that drives global warming. Biomass and bio-wastes are renewable and sustainable hydrocarbon resources, which can be used for energy and fuels production along with permanent disposal of plastic wastes. Landfills of wastes is unsustainable with additional problems of non-degradability and growing burden to the environment and society. Co-pyrolysis and co-gasification of biomass with different types of plastic wastes has shown to provide enhanced product yields and quality for syngas and liquid fuel production. To date, limited information is available on the understanding of chars produced from co-pyrolysis. The effect of co-pyrolysis on the type, quality and yield of chars produced is essential for efficient utilization of a wide variety of biomass, bio-waste and plastic waste resources. This paper provides information on the effect of plastic addition to the pyrolysis of biomass as well as the quality and quantity of char produced with different amounts of plastic waste added at different pyrolysis temperatures. TGA reactor was used for all these investigations and the quality of char produced was examined from the perspective of char combustion for energy production. Char is commonly produced as a by-product from pyrolysis and gasification reactors. Carbonization temperatures investigated were in the range of 573–773 K for 30 min using pinewood biomass, while recycled polyethylene terephthalate was used as plastic waste. The investigations revealed that chars produced from co-pyrolysis especially for carbonization temperature (T c ) of 673 K and above behaved completely differently than the chars produced from separate pyrolysis of biomass and plastic waste under the same pyrolysis conditions. These chars produced from co-pyrolysis were more uniform in their behavior in oxidation environment, with higher heat flow for almost similar quantities of chars during oxidation. This was conjectured to be from enhanced quality of chars produced having increased C content (from increased heavy aromatics and efficient loss of volatiles) during co-pyrolysis without any loss of char yield. The char yield was found to be equal or higher during co-pyrolysis compared to the weighted aggregate of individual pyrolysis. These investigations provided novel results on the behavior and capabilities of chars produced from co-pyrolysis of biomass and plastic wastes to provide a new avenue for the quality enhancement of bio-chars and efficient utilization of carbonaceous solid waste resources.

Homogeneous charge compression ignition (HCCI) is a combustion technology which has received increased attention of researchers in the combustion field for its potential in achieving low oxides of nitrogen (NO x ) and soot emission in internal combustion (IC) engines. HCCI engines have advantages of higher thermal efficiency and reduced emissions in comparison to conventional internal combustion engines. In HCCI engines, ignition is controlled by the chemical kinetics, which leads to significant variation in ignition time with changes in the operating conditions. This variation limits the practical range of operation of the engine. Additionally, since HCCI engine operation combines the operating principles of both spark ignition (SI) and compression ignition (CI) engines, HCCI engine parameters such as compression ratio and injection timing may vary significantly depending on operating conditions, including the type of fuel used. As such, considerable research efforts have been focused on establishing optimal conditions for HCCI operation with both conventional and alternative fuels. In this study, numerical simulation is used to investigate the effect of compression ratio on combustion and emission characteristics of an HCCI engine fueled by pure biodiesel. Using a zero-dimensional (0-D) reactor model and a detailed reaction mechanism for biodiesel, the influence of compression ratio on the combustion and emission characteristics are studied in Chemkin-Pro. Simulation results are validated with available experimental data in terms of incylinder pressure and heat release rate to demonstrate the accuracy of the simulation model in predicting the performance of the actual engine. Analysis shows that an increase in compression ratio leads to advanced and higher peak incylinder pressure. The results also reveal that an increase in compression ratio produces advanced ignition and increased heat release rates for biodiesel combustion. Emission of NO x is observed to increase with increase in compression ratio while the effect of compression ratio on emissions of CO, CO 2 and unburned hydrocarbon (UHC) is only marginal.

In this paper, an economic model is presented for the evaluation of gas turbine total productive life cost and profitability. The model utilizes input from gas turbine engine performance, emissions and lifing models to provide quantitative information on the economic implications of an investigated system or investment option. In this study, the proposed model is used to conduct economic analysis on a turbojet engine, repurposed for alternative profitable use in electrical power generation. Results from the analysis are compared against competitor units to determine the models economic feasibility, benefits and limitations over competitors. Results obtained from the investigation reveal that the repurposed unit is economically feasible and favours profitability at minimal investment costs, with least burden on consumers. At a discount rate of 2.5%, investing in the repurposed engine model offers an investment base 13% lower, NPV 6% higher and an LCOE 24% higher in simple cycle than in combined cycle operation.

As a promising approach for sustainable development, the distributed energy system receives increasing attention worldwide and has become a key topic explored by researchers in the areas of building energy systems and smart grid. In line with this research trend, this paper presents a case study of designing an integrated distributed energy system including photovoltaics (PV), combined cooling heating and power (CCHP) and electric and thermal energy storage for commercial buildings (i.e., a hospital and a large hotel). The subsystems are modeled individually and integrated based on a proposed control strategy to meet the electric and thermal energy demand of a building. A multi-objective particle swarm optimization (PSO) is performed to determine the optimal size of each subsystem with objectives to minimize carbon dioxide emissions and payback period. The results demonstrate that the proposed method can be effectively utilized to obtain an optimized design of distributed energy systems that can minimize environmental and economic impacts for different buildings.

Combined Cycle Gas Turbine (CCGT) power plant offer operators both environmental and economic benefits. The high efficiency achievable across a wide load range reduces both fuel costs and CO 2 emissions to atmosphere. However, the scale of the power generation plays a major role in determining both cost and efficiency: a modern large centralized CCGT of 600MW output or more will have a full load efficiency in excess of 60% and a very competitive installed cost on a US$/kW basis. The smaller gas turbines required for distributed power applications are not optimized for combined cycle operation, with potential full load efficiencies of a combined cycle scheme ranging from a little over 40% to the high 50s depending on the power output of the gas turbine, the exhaust gas conditions and the plant configuration, while the installed cost is around twice that of a large centralized CCGT on a US$/kW basis. The drawback of a conventional combined cycle plant design is the need for water, which is a scarce commodity in some regions. Air cooling of the CCGT plant can be used to reduce water consumption, but make-up water will still be required for the steam system to compensate for steam losses, blowdown etc. While the lower exhaust gas temperatures of the smaller gas turbines impact the combined cycle efficiencies achievable, they do allow Organic Rankine Cycle (ORC) technology to be considered for an alternative combined cycle configuration. This paper compares both the capital and operating costs and performance of combined cycle power plants for distributed power applications in the 30MW to 250MW power range based on conventional steam and various different ORC configurations.

Semi-coke is a specific solid fuel, which is mainly produced by upgrading low-rank coal. The poor reactivity of semi-coke makes a difficulty to its practical utilization in utility boilers. Previous research was mainly focused on the combustion behavior of semi-coke, while the industrial application has to be understood. In this paper, the effect of co-firing semi-coke and bituminous coal on the operation performance of pulverized boiler was numerically studied. The work was conducted on a 300 MW tangentially fired boiler, and the temperature distribution, the char burnout and NO x production were mainly examined. The results indicate that the incomplete combustion heat loss drops with the increase in semi-coke blending ratio. The NO x concentration increases from 186 mg/Nm 3 for only firing the bituminous coal to 200, 214, and 255 mg/Nm 3 , when the blending ratio was 17%, 33% and 50%, respectively. With enhancing excess air coefficient for the co-firing condition, the combustion efficiency got improved, while NO x production increased very slightly. In general, the boiler is well adapted to co-firing semi-coke, and the semi-coke blending ratio of 1/3 with an excess air coefficient of 1.235 is recommended.

A successful transition to a low carbon future requires that power be generated all of the time, 24/7, not just when the sun is shining. But few clean emissions power technologies can operate 24/7. Concentrated solar power (CSP) can because it can store thermal energy at 10–20% of the cost of batteries 1 and can then burn fuel when its solar resource is exhausted. However, many see first generation CSP as too costly, complex, risky, and economical only at utility scale. Alternatively, by mimicking the all-factory, standardized, modular approach of wind and PV, next generation CSP with low-cost dry thermal storage (e.g., firebrick, not molten salts), and using no water/steam (just hot air) may give CSP the potential to fulfill on its promise of baseload affordability. This technical paper summarizes an Engineering and Cost Feasibility Study 2 funded by the US Department of Energy as well as presents a new breakthrough power generation product based on the Brayton power tower system called 247Solar Plants™. Design, construction, and operation are all simplified with greatly reduced costs and increased deployment speeds. Such modular CSP systems can be installed as single units or 100s of modules at utility scale. The microturbines used by the system stabilize grids by responding nearly instantly, similar to battery response time, to changing power demands and voltage fluctuations, while offering dispatchable, reliable electricity. The redundancy of multiple modules in a single project increases capacity factor, operational flexibility, and project reliability. The DOE Study shows that such a system may be able to achieve the two key DOE targets included: 1) a capacity factor of at least 75%, of which >85% would be solar with <15% from fuels; and LCOE 3 s <9ȼ/kWh. Indeed, LCOEs under 6ȼ/kWh may be possible with further development and widespread deployment.

Based on the domestically developed urea hydrolysis reactor and urea hydrolysis ammonia process, a pilot test of urea hydrolysis was established with 10kg/h ammonia production for the flue gas denitration reductant, to reduce pollution of NOx emission from coal plant and avoid the environmental risk of liquid ammonia.The results show that urea hydrolysis reaction rate was controlled by the temperature monotonically. Steam consumption increases with the increase of pressure, especially when pressure is greater than 0.6 MPa and bring about lower economy. The higher feed concentration, the lower energy loss for the water latent heat of vaporization, and the lower operation cost of device. The maximum ammonia production is 16 kg/h, the hydrolysis conversion is greater than 98%, and the ammonia mass fraction of product gas is 22.6–34% (volume fraction of 28.5–48.0%) during the tests, at the feed concentration of 40–60%, the operating pressure and temperature of 0.6MPa and 160°C.

The increasing world energy demand as a result of society development brings forth a growing environmental concern. The use of high-efficiency alternative systems is becoming progressively more interesting due to economic reasons and regional incentives. The issue of finding the best configuration that minimizes total annual cost is not enough anymore, as the environmental concern has become one of the objectives in the synthesis of energy systems. The minimization of costs is often contradictory to the minimization of environmental impact. Multi-objective optimization tackles the conflicting objectives issue by providing a set of trade-off solutions, or Pareto solutions, that can be examined by the decision maker in order to choose the best configuration for the given scenario. The present work proposes a mixed integer linear programming model for the synthesis of a trigeneration system that must attend the electricity, heat, and cooling demands of a multifamily building complex in Zaragoza, Spain. The objective functions to be minimized are the overall annual costs and the overall annual CO 2 emissions, considering investment, maintenance and operation costs. As a first approach, the single-objective configurations for each objective function are evaluated. Then, the Pareto frontier is obtained for the minimization of total annual costs and total annual CO 2 emissions, allowing to obtain the best trade-off configuration, which brings results close to the optimal single objectives. It is worth mentioning that the treatment of the energy prices was simplified in order to keep on the same level of detail as energy CO 2 emissions, which are given only on an annual basis. On the other hand, the optimization model developed can be further complicated in order to consider more complex situations.

Owing to the growing environmental concerns, super-critical and ultra-supercritical coal-fired power plants dominate the electricity generation with the demand of near-zero air pollutant emission in China. Therefore, it is highly expected to assess the environmental impact and optimize the design at global and local levels. Exergoenvironmental analysis is a valid approach to investigate the formation of environmental impacts (EIs) associated with energy conversion systems at the component level. It generates information crucial for designing systems with a lower overall environmental impact, based on life cycle assessment (LCA) and exergy analysis. A 600 MW supercritical coal-fired system with and without dust, SO2 and NOx mitigation controls was analyzed. Heat transfer in the boiler, condenser (CND), low pressure cylinder (LP), air preheater (APH) show high potential to decrease the environmental impact due to high exergy destructions. The deaerator (DEA), induced draft fan (IDF), forced draft fan (FDF) should be focussed on construction design and manufacturing optimization. Purification units reveal high benefit for reducing EI produced by coal combustion, but there is a large space for the EI saving for it. The specific EI of electricity in China is much greater than European.

The bottlenecks which in developing high-efficiency Ultra Super Critical (USC) coal power technology is analyzed under the background of great pressure of reducing CO2 emission on coal power industry. The development of 700°C Advanced Ultra Super Critical (A-USC) technology has been much slower than expected mainly due to the material limitations. Double reheat systems increase the efficiency at the cost of significant increases in expense and complexity. A cross compound unit with an elevated and conventional turbine layout greatly shorten the expensive high-temperature piping, significantly cutting the piping costs as well as reduce pressure drops and heat losses which increase the efficiency and the performance-price ratio of the power unit. Engineering study demonstrates the feasibility and advantages of this design. Existing 600 °C materials and equipment manufacturing capabilities were applied to the double reheat unit with the elevated and conventional turbine-generator layout, and adding other mature energy-saving technologies which had succeed in Shanghai Waigaoqiao No.3 Power plant to achieve a net efficiency of 49.8% (6849Btu/kWh, Lower Heating Value (LHV)). Combined with a series of innovative technologies that can improve the operating efficiency and keep the efficiency from decreasing, the annual net efficiency can achieve 48.8% (LHV). This efficiency level is high enough to meet the strict CO2 emission standard (636g/kWh) issued by Environmental Protection Agency (EPA) of the USA, showing significant demonstration of reducing CO2 emission.

Renewable energy technologies and sources have been playing a key role in reducing CO 2 emissions and its footprint. Solar energy which is one of the major renewable energy sources can be utilized by means of solar Photovoltaic (PV) or solar collectors. Concentrating solar collectors supply thermal energy from medium to high grade where as non-concentrating collectors (flat plate) delivers low-grade thermal energy. The use of thermofluids with boiling temperatures lower than water, allows the operation of low grade solar thermal systems on an Organic Rankine Cycle (ORC) to generate both mechanical and heat energy. At the same time, the selection of an appropriate thermofluid is an important process and has a significant effect both on the system performance and the environment. Hydrofluoroethers (HFEs) are non-ozone depleting substances and they have relatively low global warming potential (GWP). In this study, a solar ORC is designed and commissioned to use HFE 7000 as a thermofluid. The proposed system consists of a flat-plate solar collector, a vane expander, a condenser and a pump where the collector and the expander are used as the heat source and prime mover of the cycle respectively. The performance of the system is determined through energy analysis. Then, a mathematical model of the cycle is developed to perform the simulations using HFE-7000 at various expander pressure values. Experimental data indicates that the efficiency and the net mechanical work output of the cycle were found to be 3.81% and 135.96 W respectively. The simulation results show that increasing the pressure ratio of the cycle decreased the amount of the heat that is transferred to HFE 7000 in the collector due to the increased heat loss from the collector to the environment. Furthermore, the net output of the system followed a linear augmentation as the pressure ratio of the system increased. In conclusion, both the experimental and theoretical research indicates that HFE 7000 offers a viable alternative to be used efficiently in small scale solar ORCs to generate mechanical and heat energy.

In order to reduce CO 2 emission from thermal power stations with keeping high thermal efficiency, a new concept of IGCC system, namely oxy-fuel IGCC, has been recently proposed. Hence CO 2 is recycled in the system, the effect of CO 2 recycle on each equipments should be clarified. In this study, the effect of recycled CO 2 injection on coal gasifier performance was investigated by means of three-dimensional RANS-based numerical simulation. For estimating of coal gasifier performance, coal gasification and water-gas shift reaction are key phenomena. Therefore, the partially active site sharing coal gasification model and detailed chemistry of water-gas shift reaction model were implemented. Calculated gasifier was a commercial scale entrained flow coal gasifier whose coal feeding rate is 70 tons per hour. The gasifier consists of a lower combustor part and an upper reductor part. The effect of coal feeding rate into the reductor, R/T, was investigated. The results show that temperature in the combustor decreases with decreasing R/T. In the lower R/T condition, hence air ratio in the combustor decreases, the reducing atmosphere becomes stronger. As a result, coal gasification which is endothermic reaction in the combustor is promoted. Although coal gasification is occurred in the reductor in higher R/T condition, total coal gasification rate is not so promoted compared with lower R/T condition. Due to the above mechanism, the gasification performance becomes higher with decreasing R/T. The results obtained in this study indicate that it is important that how much the higher gasification reactivity in a gasifier is exploited by optimizing local heat balance.

In recent years, global warming and climate change caused by the greenhouse gas emissions has given rise to widespread concerns. CO 2 has been considered as the principal greenhouse gas of interest, and fossil-fuel-fired power plants have been deemed as the largest stationary sources of CO 2 emission. It is imperative to capture CO 2 from these sources to reduce the global CO 2 emissions. Lately, capturing CO 2 from flue gas using solid absorbents shows promising for CO 2 abatement. For the cost-effective CO 2 capture process and the recycling of environmental pollutants, deprecated resources have been utilized for CO 2 capture from flue gas. In this work, fly ashes derived from different raw materials were tried as solid CO 2 sorbents for flue gas treatment. To improve their CO 2 capture capacities, the ashes were modified by different polyamines. An experimental demonstration on CO 2 capture behaviors of fresh ashes and modified sorbents in simulated flue gas atmosphere of 40°C, 15% CO 2 + 15% H 2 O and balanced N 2 was presented in detail with a fixed-bed reactor system. CO 2 capture capacities of fresh ashes were calculated as 0.56 mmolCO 2 /g, 0.32 mmolCO 2 /g, 0.44 mmolCO 2 /g and 0.83 mmolCO 2 /g, respectively. By contrast, CO 2 capture capacities of amine-modified samples had been enhanced as 0.38 mmolCO 2 /g, 0.65 mmolCO 2 /g, 1.07 mmolCO 2 /g, 0.85 mmolCO 2 /g and 1.17 mmolCO 2 /g. The optimal sample of TEPA-modified biomass ash (TEPA-BA) with CO 2 capture capacity of 1.17mmolCO 2 /g was screened. The optimal candidate was then selected for further investigation of the effects of temperature, CO 2 concentration and H 2 O concentration on its CO 2 capture behaviors. The results indicated that CO 2 capture capacity would increase with the increase of temperature in the range of 30 to 40 °C and decrease with the increase of temperature in the range of 40 to 60°C, increase with the increase of CO 2 concentration in the range of 5% to 20%, increase with the increase of H 2 O concentration in the range of 0% to 15% and decrease with the increase of H 2 O concentration in the range of 15% to 20%. The results in this work could provide basic data as a guidance for further applying the sorbents in practical operations.

Coal is regarded as important fuel because of its stable supply and low price, but coal is blamed for its CO 2 emission. Japanese utilities are making efforts to improve thermal efficiency and to expand biomass co-firing. On the other hand, CCS technologies are under development as a countermeasure for global warming and demonstration projects planned in several power stations are announced in world wide. As CO 2 capture from power station requires huge in-house power, thermal efficiency is deteriorated. To make a breakthrough, NEDO started a project to develop the high-efficiency oxy-fuel IGCC system. This system recirculates gas turbine exhaust gas to both gasifier and gas turbine combustor. Recirculated exhaust gas is used both to feed pulverized coal to gasifier and to dilute syngas in gas turbine combustor. The target efficiency is 42% at HHV basis, equivalent to state of the art coal-fired power station. Various studies were done to confirm the concept of this system and to develop fundamental technologies necessary for the system since 2008 to 2014 as NEDO project. Based on the achievements, the project made another step since 2015 as a five-year joint NEDO project with MHI and MHPS. This paper introduces the latest status of this project executed by CRIEPI by referring several related papers.

A 600MW tangentially fired sub-critical boiler with the volume heat load of 87.6kW/m 3 at the case of BMCR was not originally equipped with the separated over fire air (SOFA) system. Shenhua bituminous coal with low ash fusion point and strong slagging characteristics is employed as its design coal. To prevent serious slagging on its platen heaters, it is necessary to employ 80% Shenhua bituminous coal with low ash fusion temperature blending 20% Shenhua bituminous coal with high ash fusion temperature. However, NOx emission value at the furnace exit reaches more than 370mg/m 3 (O 2 = 6%). In order to achieve a NOx emission limitation level below 100mg/m 3 (O 2 = 6%) for pulverized coal power boilers which meets the requirement from latest Chinese environmental protection regulation, while considering a low cost of retrofit, a comprehensive low NOx emission boiler retrofit scheme combining air-staged low NOx combustion technology and selective catalytic reduction of flue gas in the low temperature flue duct of boiler was selected preferentially. Two-level air staging technology has some obvious advantages including a little negative effect on the boiler’s combustion efficiency, and easily achieving deep air-staged combustion mode. Therefore, a study of numerical simulation concerning original combustion mode and optimized two-level air staging combustion mode was conducted. Due to excellent ignition and burnout characteristics of Shenhua bituminous coal with high volatile matter, low ash fusion temperature and reasonable configuration of upper and lower burnout air ports, the NOx emission level at the exit of furnace would be greatly reduced, and the fouling layer temperature of water wall obviously decreases, which means a definite improvement of clean degree of furnace. And the gas temperature at the bottom of platen heaters decreases about 20 °C while burning 100% Shenhua bituminous coal with low ash fusion temperature. However, its combustion efficiency would decline weakly. The performance of boiler was optimized by combustion tests after the retrofit. This boiler can fully burn Shenhua bituminous coal with low ash fusion temperature by use of two-level air staging system, and furnace soot blowing frequency also lowered. Consequently, exhaust gas temperature decreased, which achieved an increase of boiler efficiency by about 0.3%. In addition, NOx emission level decreased more than 60%, and was about 15 mg/m 3 (O 2 = 6%) lower than coal blending cases. To meet a full burning of Shenhua bituminous coal with low ash fusion temperature, it is suggested that two-level air staging technology should be applied to the retrofit of boiler. And then goals of low NOx emission and anti-slagging on the platen heaters can be achieved.