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A cascade-arch-firing low-NOx and high-burnout configuration (CLHC) is developed to strengthen low-NOx combustion and maintain high burnout in down-fired furnaces. Numerical simulations of the in-furnace flow field, coal combustion, and NOx formation are performed in a 600 MWe down-fired furnace to evaluate the staged-air location's effect on the low-NOx and high-burnout performance. The furnace, which is in service with a deep-air-staging multi-injection and multi-stage combustion technology (MIMSCT), was modified with the CLHC combustion system for the present simulations. Various staged-air location coefficients of CH = 0.65, 0.70, 0.75 and 0.80 were analysed. Moving downward staged-air to enlarge CH initially improves but then deteriorates the in-furnace flow-field symmetry. Similar changes in the gas temperature and species distribution patterns in the furnace are evident. As CH increases from 0.65 to 0.75, levels of the residual O2 concentration, carbon content in fly ash, and NOx emissions at the furnace outlet decline continuously. The highest setting CH = 0.80 generates severely asymmetric combustion accompanied by poor performance indexes, raising the unburnt rate and NOx emissions by 20–30%. The staged-air location of CH = 0.75 achieves a symmetric flow-field pattern, satisfactory low NOx emissions of ~670 mg/m3 at 6% O2 and high-burnout performance with carbon in fly ash of 5%. NOx emissions are reduced by 26% without affecting burnout in comparison to the currently advanced deep-air-staging MIMSCT.

The main problem related to thermal energy is that the thermal energy must be used directly and immediately as generated. For example, the thermal energy of solid waste combustion can be directly utilized for power generation. However, studied of thermal energy storage technology is still placed on the second opinion on waste to heat energy. The heat can be stored using a simple or mobilized system which can store thermal energy and can be brought to somewhere it is needed, for example on domestic heating or drying usage. This article studied and evaluated a micro thermal energy storage system from household waste combustion into a warm water that is great for washing clothes, dishes, shower, and other purposes of household needs. System considered was a simple manner and water is used as the heat energy storage medium. In this study, the equations for initial parameter calculation were presented theoretically based on thermodynamic principle. This paper is hopefully beneficial to the researchers and engineers for preliminary design and development of a heat storage systems technology.

It is shown that the modernization of boilers for a low-temperature vortex (LTV) technology of coal combustion can provide a comprehensive increase in their energetic and environmental performance characteristics and the efficiency of ash collectors. Specific emissions of heavy metals with ash particles carried into the atmosphere per unit of generated energy in a boiler unit with a low-temperature vortex technology are much lower than those in a boiler with a traditional combustion system.

CCS (Carbon Dioxide Capture and Storage) is one of the technologies able to adequately displace CO2 from fossil fuel fired power plants and the only technology capable of reducing large-scale emissions. In particular, coal emits a lot of CO2, although it is an important energy resource in terms of energy security. To address this situation, IHI had developed oxyfuel combustion technology to capture CO2 from coal-fired power plants, and the demonstration using a 30MWe unit in Australia was successfully carried out. In order to commercialize the technology widely, how to configure the primary gas system is one of the important examination items. When adding oxygen into the primary gas system, depending on the type of mill, pulverized coal deposited in the mill may ignite spontaneously. To investigate the spontaneous combustion characteristics of the deposited pulverized coal under oxyfuel conditions, therefore, laboratory-scale experiments were carried out. The pulverized coal was deposited in a 100mm square mesh box, and it was installed in a thermostatic chamber. Then the mixed gas of N2/O2 or CO2/O2 was introduced into the chamber, and the temperature in the coal sample was measured. From the results, there was little temperature difference at which spontaneous combustion occurred between N2/O2 and CO2/O2 atmosphere, while there was a tendency that it might be relatively hard to occur under CO2/O2 atmosphere. The results also showed a tendency that the influence of temperature was stronger than the oxygen concentration.

Industrial gas turbines serve in a variety of markets involving wide ranging duty cycles, fuel types and quality and emission requirements. For the Oil & Gas markets, applications range from mechanical drive, compressor sets and electrical generation that may be located in developed, remote or off-shore areas requiring a backup fuel (usually a liquid fuel). Upstream applications often require the gas turbine to burn a wide Wobbe range of fuels with varying gas compositions. For Power Generation applications, flexibility in operating range and low emissions are usually required. This paper describes Solar’s latest SoLoNOx™ (DLE) combustion system developments for the Titan 250 for both gaseous and liquid fuels with a focus on fuel type and quality, operability and emissions from both rig and engine tests. Several combustion systems will be discussed including gas only, dual fuel and a dual fuel Lean Direct Injection (LDI) system for burning lower quality liquid fuels. Engine tests were performed with blends of reactive gases (propane and butane), inert gas (carbon dioxide) and natural gas covering a wide Wobbe range from 30 to 60 WI (MJ/Nm3). Full engine qualification testing was performed which included operability, emissions and combustion stability for both the gas only and LDI combustion systems. The LDI system is based on the dry low emissions combustion system used for gas operation and thus offers low NOx emissions on gaseous fuels with the ability to burn lower quality liquid fuels for backup operation. A dual fuel lean premixed combustion system was also fully engine qualified for natural gas and liquid fuel. High pressure single injector rig tests using hydrogen blends with pipeline quality natural gas were also performed to qualify these fuels for engine operation in the dry low emission combustion systems with up to 30% hydrogen. The primary focus of testing was to determine overall operability, turndown, flashback risk and emissions.

This paper focuses on the description, function and working principles of the wet gas scrubber required to control air pollution emissions from a combustion system of a boiler. Important points to note in the selection and operation of the scrubber as well as the different types of scrubbers commonly deployed in the industries to cut down on emissions were addressed. A comprehensive reviews of the removal mechanisms and schemes of the scrubber were reported for various research on the subject. The packed tower scrubber, however, was recommended because of varying advantages and ease of operations.

The paper presents results of analysing the most commonly used measures for improving combustion of wood and agro pellets in domestic combustion appliances. This includes numerical and experimental analysis of the combustion chamber partial insulation and inclusion of combustion intensifier in the conventional combustion system on the obtained combustion efficiency and reduction of pollutant emission. The results show that significant reductions in unburned pollutant emissions can be obtained by both measures, while the improvements in combustion efficiency and particulate matter emissions only with the inclusion of combustion intensifier.

The cyclonic gasification technology could realize self-separation of syngas and residual carbon, simplifying the purification system. In cyclone pyrolysis-suspension combustion system, bottom air was fed into carbon-rich area of gasifier. Due to the high height/diameter ratio and uneven temperature distribution in cyclone gasifier, the primary/secondary/bottom air rates were 30%, 20%, and 50%, respectively. Effects of gasification intensity and air equivalent ratio on rice husk gasification performance were explored. The results show that for cyclone pyrolysis-suspension combustion, the optimum gasification intensity is 885.24 kg/m2h. Strengthening the subregion of air supplement could cause a gradual increasing of temperature along the axis of gasifier. The syngas yield was independent of gasification intensity, but increased from 0.98 Nm3/kg at ER = 0.23 to 1.38 Nm3/kg at ER = 0.32. At ER = 0.26~0.29, the gasification performance is best, with gas heat value of 4.99~5.37 MJ/Nm3, cold gasification efficiency of 48.25~49.67% and tar content of 5.38~5.75 g/Nm3.

Tritium is ubiquitous in and around nuclear plants, being formed via neutron capture by 2H, 6Li, 10B and 14N and via ternary fission. The highly mobile nature of 3H species results in widespread distribution of the radionuclide. Predictive modeling of 3H activity concentrations is challenging and direct measurement of 3H activities in materials is the preferred approach to underpin waste and environmental assessments. For well over a decade, the UK nuclear industry has engaged in a significant program of site decommissioning of its first generation reactors. This has resulted in a high demand for the rapid characterization of 3H in a diverse range of matrices, including concretes, metals, plastics, sludges, resins, soils and biota. To support such assessments, it has been necessary to develop dedicated instrumentation in parallel with robust radioanalytical methodologies; namely a multi-tube furnace and a high-capacity, closed (pressurized) oxygen combustion system. Data are presented on the development and validation of these instruments, designed specifically to enable the quantitative extraction of 3H (and other volatile radionuclides) from diverse sample types. Furthermore the furnace system has been employed as a tool to gain insights into the 3H association in decommissioning and environmental matrices exposed to 3H arising from nuclear power plant operations through tritium evolution with temperature profiling. The impact of the chemical speciation of 3H on analytical strategy is discussed. A major benefit of the multi-sample furnace is its ease of use and applicability to 3H determination in virtually any sample type. The complementary HBO2 oxygen combustion system has been developed for the quantitative oxidation of organic-rich samples (e.g. wood, plastic, oil, biota) and analytical data prove its effectiveness.

To achieve significant reductions in NOx emissions without increasing the levels of unburnt carbon in the fly ash, a new combustion system was applied to a 300-MWe Babcock & Wilcox (BW however, for the vane angle of 35° the flame is spread across the entire furnace cross-section at inspection port 2. For this optimal (35°) inner secondary-air vane angle, the NOx emissions and carbon content in the fly ash reached levels of 674 mg/m3 (6% O2), and 11.4%, respectively, achieving a significant NOx reduction of 51.9% without increasing the levels of unburnt carbon in the fly ash.

A fixed-bed combustion system was used to study the NO emission characteristics of co-combustion of biomass and coal in an O2/CO2 atmosphere. With the concentration of oxygen varied in 21%, 30%, and 40% while the biomass blended proportion mounts raised from zero to 10% then to 30%, the generated NO was classified to Vdaf-NO and FCad-NO, respectively, and the emission rate and conversion ratio of NO were analyzed. The results showed that the NO emission rate and concentration increased with increase in oxygen concentration, but the conversion ratio decreased. Meanwhile, the blended biomass reduced the NO emission concentration and conversion ratio.

A novel combustion system has been applied to a 600 MWe down-fired boiler to reduce NOx emissions without producing an obvious increase in the carbon content of fly ash. The system mainly includes moving fuel-lean nozzles from the arches to the front/rear walls, and re-arranging the staged air, as well as introducing separated-over-fire air (SOFA). This paper evaluates the effects of the SOFA locations (on the arches, on the throat, and on the upper furnace) on the combustion and NOx emissions characteristics using simulations. The numerical results are in good agreement with the measured results. Compared to the original combustion system, significant NOx reduction (approximately 50%) is found for all three SOFA location settings. Taking economic efficiency and NOx emissions into account, the SOFA on the upper furnace is adopted in the actual modification, and no negative effects are observed.

A 600MW supercritical direct-current (DC) utility boiler co-firing bituminous coal with lignite, has the problems from over-large desuperheating water yield in the reheater and over-high NO x emission concentration. In this paper, the causes of the problems are analyzed through, the initial tests of pulverization system and combustion system, the adjustment of combustion, etc. The results show that the combustion in furnace lagged behind to some extent after co-firing the bituminous coal with the lignite and the center of the flame was elevated, which shortened the relative distance between the flame of the main burners and over fire air(OFA), enlarged the absorbed heat amount of the reheater and reduced the residence time of flame in the reduction zone prominently. The much less residence time would increase NO x emission. Based on the calculations of the actual operation conditions of the burners, a series of improvement measures were proposed. After performing numerical simulation and cold test verification for the improvement measures, the corresponding transformations of the power plant were carried out. The desuperheating water yield in the reheater decrease, obviously, and over-high NO x emission is controlled effectively.

In this paper, a waste heat recovery comparison of oxygen and air combustion in a glass melting furnace has been done by using the net present value method. Results show that the optimal numbers of transfer unit are existed both in oxy-fuel and air-fuel combustion systems, which have the same value, to make them get the best economic benefit. At the highest net present value with the number of transfer unit, the oxy-fuel combustion system has less economic benefit but is friendly to the environment than the air-fuel combustion system.

An innovative combustion system, the so-called low-emission combustion system (LEVS), with integrated exhaust gas treatment measurement for thermal utilization of biomass-fueled boilers is presented. It comprises an intelligently controlled three-fan combustion air supply and exhaust gas system, a cyclone combustion chamber, and packed-technology, ensuring high combustion efficiency and stable low-emission combustion. The technology was tested by preliminary experiments for various application scenarios of biomass, and the current environmental and health-related aspects were also evaluated. The relevant emission reduction through the system results from improved combustion in critical operating phases, in which the total emissions produced in conventional gasification boilers are drastically reduced. A minimum increase of the boiler efficiency of 15 % in practice with corresponding fuel and CO2 savings can be guaranteed.

To reduce NOx emissions without introducing an obvious increase in the carbon content of fly ash, a novel combustion system was applied to a 600 MWe Foster Wheeler (FW) down-fired boiler. This approach mainly consisted of moving fuel-lean nozzles from the arches to the front/rear walls, rearranging staged air, and introducing separated overfire air (SOFA). The aim of this work was to evaluate the overall performance of the novel combustion system relative to different SOFA ratios (i.e., 15, 20, 25, and 30%) and different SOFA locations in the upper furnace (1.0, 2.0, and 3.0 m above the arches) using numerical simulations and experimental measurements. Both numerical and experimental results showed that, with increasing the SOFA ratio from 15 to 20%, NOx emissions were greatly reduced but the carbon content in the fly ash increased slightly. With a further increase from 20 to 30%, NOx emissions slightly decreased but the carbon content in the fly ash increased substantially. Considering both the environme...

Nowadays, industries have been using combustion system as one of energy supply in their utility system. However, incomplete combustion process often takes place in the process, which resulted in several disadvantages for the industry such as less energy efficiency, higher CO emission and higher production cost. The aimed of this study was to understand characteristics and increasing combustion efficiency in fuel preheating system technology and to find out the effect of various initial temperature of LPG to combustion efficiency and CO emission. Results showed that increasing initial temperature of LPG from 28 °C to 50 °C would raise efficiency of the burner up to 6.75% while CO emissions decreased 49.06%. Furthermore, if the temperature increased up to 100 °C the burner efficiency would raise significantly and CO emissions considerably decreased.

This paper introduces two modeling methods of the incinerator’s combustion control system. Aiming at the features of the control system which apply to the incinerator’s combustion system, this paper uses the techniques of system identification which are based on the least square method and the neural network, introduces two ways of model identification in the incinerator’s combustion control system, then they can be helpful for the following design of the control system. By simulating the model of the incinerator’s combustion control system, desired results can be obtained for following the track of the main control target-temperature.

A 600MW tangentially fired sub-critical boiler with the volume heat load of 87.6kW/m3 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/m3 (O2 = 6%). In order to achieve a NOx emission limitation level below 100mg/m3 (O2 = 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/m3 (O2 = 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.

The mechanism of NOx formation in coal combustion, NOx control methods and key DeNOx technologies is to be introduced. Denitrification is very significant for saving energy and carbon sources. By analysis of NOx production mechanism, the principles of controlling NOx production and lowering emission of NOx by classified combustion are described. Combined with actual operation, low-NOx combustion rehabilitation programs and relevant test to be done is to be proposed. The actual operation of the unit achieved good results after the transformation, provide a reference for similar units.

There exist many dangerous and harmful factors in by-product steel gas power generation process and which easily caused casualties and the pollution of the environment. The study on risk analysis and evaluation are still relatively dearth about the by-product gas generating process of domestic steel enterprises. The boiler system on a Combined Cycle Power Plant was analyzed and evaluation by Dow chemical fires and explosive hazard index evaluation method and the method of fault tree analysis, which combined with the actual situation of steel plant Combined Cycle Power Plant. The results show that the fire and explosion hazard of gas boiler is very dangerous, but the hazard levels are reduced to lower level after safety compensatory measures, so the safety of the device is reliable, and immediately pay is the main reason leading to the explosion of the boiler. According to the analysis some feasible measures was put forward. The study has positive guiding significance for risk management and safety administration decision of the Combined Cycle Power Plant.

The paper presents the most important aspects regarding the low swirl combustion system (LSC), the design of the low swirl burner (LSB), the development and technological transfer stages from the lab-testing burner to the burners used in the high power gas turbines. The development of this low swirl combustion technology was required by the bigger and bigger constraints on the burning equipments that use fossil fuels, regarding the reduction of pollutant emissions. The low swirl combustion technology is an easy and cheap way to ensure the efficient combustion of the fossil fuels with a low level of pollutant emissions.

Plasma activation is an innovative concept for converting liquid or gaseous fuels into reactive species. However, there are few studies that focus on activating air to enhance combustion efficiency and reduce emissions of toxic pollutants such as PAHs. In this study, a plasma-enhanced combustion system was used to increase the amount of free radicals in intake air and enhance the combustion efficiency. The experimental results show that the reduction in pollutant emissions was enhanced with the increase in voltage, and that this also reduced the amount of fuel used. The optimum voltage of the plasma-enhanced system was 3200 V, and this reduced total PAHs by 20.7%, total BaPeq by 20.5%, CH4 by 50.0%, NMHC by 57.7%, THC by 57.1%, CO by 60.2%, NOx by 70.7%, CO2 by 19.8%, and PM by 42.8%, and achieved fuel savings of 12.1%.

Practical applications involving combustion suffer from serious issues such as combustion instabilities and sudden loss of flame: flame flashback and blowout . These phenomena are related to dynamical changes in the combustion system. Here, we summarize our recent studies on the application of recurrence-based methods to identify such dynamical transitions as well as for the characterization of combustion dynamics in laboratory combustors.

This paper examined and assessed various configuration options about emission removal including particles. SOx and NOx in an oxy-coal combustion system for CO2 capture. A performance analysis was c ...

Based on the analysis of the gas fuel resources, the development potential of gas engines in China is evaluated. And contribution of application of gas engines on the reduction of Green House Gas (GHG) emissions as well as harmful emissions is estimated. Since gas engines are different from conventional internal combustion engines on fuel system and combustion system, the key technologies relating to developing gas engines are introduced, and the major difficulties of popularizing of gas engines are discussed. With the foundation of the analysis, development strategy of gas engines is proposed.

Mass balances of ash and potassium for a fluidized bed combustor were performed incorporating measurement uncertainties. The total output mass of ash or a chemical element should be equal to the mass in the input fuel; however, this is not often achieved. A realistic estimation of recovery uncertainty can support the reliability of a mass balance. Estimation of uncertainty helps to establish a reliable evaluation of the recovery ratio of ash mass and elemental mass. This may clarify whether any apparent lack in closing the mass balance can be attributed to uncertainties. The evaluation of measurement uncertainty for different matrices, namely coal, biomass, sand and ashes from different streams was based on internal quality control data and external quality control data, namely analysis of samples from proficiency tests or use of a certified reference material. The evaluation of intermediate precision and trueness allowed the estimation of measurement uncertainty. Due to the different physic and chemical characteristics of the studied matrices, the uncertainty of precision was evaluated using R-charts of data obtained from the analysis of duplicates for the majority of samples. This allowed evaluating sample heterogeneity effects. The instrumental acceptance criterion was also considered and included in the combined uncertainty. The trueness was evaluated using data from several proficiency tests and from analysis of a certified reference material or sample spiking. Statistically significant bias was included.

Doosan Power Systems has adopted an evolutionary approach to the design and implementation of OxyCoal™ technology combining well proven and commercially available components with state-of-the-art advances in technology, and is leading a number of UK Government supported collaborative projects that are developing oxyfuel combustion technology. The “Demonstration of an Oxyfuel Combustion System” OxyCoal 2 project aimed to demonstrate an oxyfuel combustion system of a type and size (40MW t ) applicable to new build and retrofit advanced supercritical oxyfuel plant. Following conversion to oxyfuel firing, the Clean Combustion Test Facility (CCTF) became the world’s largest demonstration facility of an oxyfuel combustion system, and since the official opening on 24th July 2009 a test programme has been successfully undertaken to demonstrate the full-scale Doosan Power Systems first generation 40MW t OxyCoal™ burner on air and oxyfuel firing, achieving safe and stable operation across a wide operational envelope and CO 2 flue gas concentrations in excess of 75% v/v dry, and up to 85% v/v dry. The OxyCoal 2 project is discussed in the paper and results from testing the full-scale 40MWt OxyCoal™ burner firing bituminous coal in both air and oxyfuel firing operation are presented.

The qualities of the limestone conveyor system running directly affect the efficiency of circulating fluidized bed boiler combustion. Aiming at the problems of limestone conveyor system, this paper optimizes the design of the control system and the ring limestone fluidized bed boiler combustion control system networking, the use of configuration technology for real-time data control system to monitor and implement manual and automatic switching function. While improving the delivery system and improve the combustion efficiency of the boiler. For the circulating fluidized bed boiler combustion system provides a reference value.

Due to stringent regulations, there has been considerable effort to reduce NO x emissions. In this study, we numerically investigate the details of NO x reduction in a mid-/large-sized combustion system employing a new novel flue-gas internal recirculation burner is thoroughly studied with emphasis on the effects of buoyancy and thermal radiation. The NO x emission in the flue-gas internal recirculation combustion system is observed to be half the value in the non-flue-gas internal recirculation system due to lowered temperature. The present combustion system is large enough for the natural convection to be established and as a result the buoyancy effects become remarkable even though the fuel and air are introduced in the transverse direction. Interestingly, the buoyancy augments the NO x formation in the non-flue-gas internal recirculation system, whereas it reduces the NO x emission in the flue-gas internal recirculation system. Contrary to the thermal radiation, the buoyancy effects in large-sized combustion systems have not been systematically studied yet. Also, the numerical prediction of NO x emission with computational fluid dynamics is accurate only when the buoyancy and thermal radiation are considered together. The present finding about NO x emission, buoyancy, and thermal radiation is expected to be very useful in innovating the ultra-low NO x combustion systems.

Due to changing economic, technical and social environments and resulting customer demands, future vehicle drive systems will be required to have lower pollutant emissions and greater efficiency, leading to a CO2 reduction. Combining the advantages of the petrol and diesel combustion processes is a way of achieving these objectives. In the Group Research — Drive Systems of Volkswagen AG, this implementation is referred to as the Combined Combustion System CCS.

Future emission norms will further reduce the vehicle emissions of diesel engines. To meet the goal of achieving these stringent limits while maintaining attractive attributes of marketability, the combustion system needs also to be revised or redesigned in order to achieve the CO2 limits that will be demanded in the future, while simultaneously producing significantly reduced untreated NO2 emissions. In the scope of this article, the basic conditions for the design of future combustion systems shall be discussed. As a possible solution, we will introduce the FEV combustion system HECS (High Efficiency Combustion System), with which very low fuel consumption can be obtained even at high part loads, while producing minimal nitrogen oxides.

Burner and combustion safety is crucial for the safe operation of fuel-fired heaters and boilers at process industry facilities. This paper discusses 10 of the most common burner and combustion system hazards that impact the safe operation of combustion equipment. The paper includes a discussion of three burner related explosion incidents that occurred at plants and how to avoid them. Strategies are also presented for training of maintenance and operations personnel on hazard recognition and avoidance. A protocol for walking down equipment prior to light offs is also presented as an extra safety step.

The main features of low calorific gases as those from biomass gasification processes, landfills, mines and sewage sludge are well known. They can be expressed as low calorific values, high water content, corrosive actions and composition changes. Due to these characteristics there are up to date no combustion systems available which are capable to utilise such gases efficiently. The ordinary combustion concepts frequently do not guarantee sufficient flame stability. The high emissions of harmful substances as CO and NOx are another problem. Because of mentioned difficulties it is necessary and also a challenge to develop an efficient and flexible combustion system which can handle these problems. Through several matching steps of numerical and experimental investigations Gaswarme-Institut e. V. Essen (GWI) developed a progressive combustion system based on the concept of continuous air staging (COSTAIR). Burner tests at a small scale thermal load of 30 kW proved a stable combustion and low NOx and CO emissions for different qualities of low calorific gases. The best design of a small scale burner was transferred to larger thermal loads by applying of scale-up criteria. Already achieved experimental results at 200 kWth confirmed the efficient performance and the high potential of the burner for use of low calorific gases.

Experiments with a newly designed controlled multiple air staging technology (CMAST) in grate firings show a considerable reduction in NOx emissions. The applicability of the CMAST depends on fuel parameters. Fuels with high moisture content cause a drop in the heat output during full load operation due to the reduced fuel conversion. Due to reduced temperatures in the furnace, the emissions of products of incomplete combustion rise during part-load operation. More primary air is necessary to decrease incomplete combustion products, thus preventing the successful implementation of the multi-air-staging technique. Experiments in the laboratory, and test and commercial firings assist in understanding the influence of different fuel characteristics on the combustion system, and detect practical potentials and limits of air staging. On this basis, concepts have been developed for an optimised operation of grate firings dependent on the fuel characteristics. These results promise a further improvement of combustion technology using wood fuels.

With forthcoming Euro 5 regulations on emissions levels in 2008–2010, the challenge for diesel engines consists in drastically reducing NOx and particles emissions. To that end, IFP has developed a new combustion system called NADITM (Narrow Angle Direct Injection) with an innovative air intake architecture designed by Valeo that strongly reduces NOx emissions without impairing fuel consumption. The system is based on a low temperature combustion that uses cooled recirculated exhaust gases.

The bolier systems of coal fired power plants are large, non-linear systems with numerous interactions between its component parts. In the analysis of such complex systems, dynamic simulation is recognized as a powerful method of keeping track of the myriad of interactions. The boiler system consists of air/gas system and water/steam system. Due to recent reinforcement of environmental regulation on pollutant discharge and requirements of design validation on properites of boiler, the commercial programs are used for the analysis of boiler system. This paper addressed to the development of model using MMS(Modular Modeling System) developed by EPRI(Electric Power Research Institute) as the simulation tool. The developed model using MMS is tested for the design and local data on boiler combustion system of korea standard coal fired power plant boiler. The simulation results show that the developed model well reproduces responses of the combustion system with less than 5% error under steady state and transient state conditions. The developed model for analysis of the combustion system in this paper is general and applicable to any type of coal fired power plant.

A gas turbine is well known as a clean thermal engine system, and it has an advantage of availability for multi-kinds fuels as a continuous combustion system. But it has not been popularized so much by its own low thermal efficiency. Recently, arranging the co-generation and the combined cycle, the gas turbine system has been reconsidered.In this report, we have investigated the availability of vegetable oils as a blender to a fuel for making good use of a gas turbine.After all, a waste oil (vegetable oil) was a good blender to a A -heavy fuel. The performance has good con-ditions.