Amount Of Combustion Air Research Articles

Comparison of DeNOx additives in SNCR fluidized bed boiler system

Due to decreasing BAT emission limits of NOx the owners of heating plant are looking for DeNOx solution, especially by solid fuel firing boilers. Fluidized-bed boil-ers combustion temperature is generally lower, and some primary precautions were sufficient. Nowadays lots of plants install secondary precautions (especially SNCR) into their boilers due to increasing periods of exceeding emission NOx limits. The article is about comparison of water solution of urea (41 % wt.), ammonium sulfate (33 % wt.) and am-monia (22 % wt.) and their utilization in SNCR technol-ogy. Laboratory determination specified exact content of functional substance and content of redox nitrogen. Also, significant content of heavy metals was not detected. Operational tests were realized in CFB coal-biomass boiler (steam parameters: 140 t·h-1, 525 °C, 12.5 MPa). Dosing of DeNOx additives were only during boiler per-formance higher than 92 %, for lower performance pri-mary precautions were sufficient. There was higher tem-perature through the combustion chamber during active SNCR dosing (877 °C, standard temperature 850 °C), alt-hough the amount of combustion air was increased. Com-plication connected with high emission of NH3 was not detected. Lower emission of CO was also detected. All three additives are suitable for application in SNCR technology. To reach emission limits were needed 3.7 l·h-1 of ammonia solution, 5.04 l·h-1 of urea solution and 5.74 l·h-1 of ammonium sulfate solution. After recal-culation it means 0.65 kg·h-1 (ammonia), 1.1 kg·h-1 (urea) and 0,38 kg·h-1 (ammonium sulfate) of redox nitrogen content.

Методологічні основи визначення і контролю витрат біопалив у процесі руху автомобіля

The paper proposes a methodological approach to determine and control fuel consumption (biofuels) of a car that has known design parameters and moves in known conditions at known modes. It is noted that at this stage it is more attractive to use mixed fuels based on gasoline or diesel fuel with the addition of various impurities of biological origin. For gasoline-based fuels, impurities can be methyl or ethyl alcohol, for diesel fuel – vegetable oils, as well as their methyl and ethyl esters of these oils. A structural and logical scheme has been developed, which explains the main provisions of the proposed determining method and controlling the biofuels consumption. In the structural and logical scheme, the following groups of parameters that take place during the car movement are highlighted: parameters of the conditions, the driving mode design. The mutual influence of parameters among themselves and between groups, the influence of the biological component concentration on its consumption, which must be taken into account to determine and control the consumption of biofuels during the movement of the car, was analyzed. It is shown that when switching to the use of biofuel, there is a change in the indicator coefficient of the internal combustion engine, which also affects the change in consumption.It has been proven that in the process of using biofuel, important factors affecting its consumption are density, lower heat of combustion, and the theoretically required amount of air for kg of biofuel combustion, which depends on the volumetric a specific biological component concentration in it. It has been proven that in the biofuel use process, important factors affecting its consumption are density, lower heat of combustion and the theoretically necessary amount of air for combustion in 1 kg of biofuel, which depends on the volumetric a specific biological component concentration. Taking into account the relative indicators of the «main» fuel (lower combustion heat, density and theoretically necessary air amount for the combustion of 1 kg impurities), it was established that the smallest increase in fuel consumption by the car engine during operation occurs when rapeseed oil is added to diesel fuel.

Parametric Studies of Cement Production Processes

The cement industry is one of the most intensive energy consumers in the industrial sectors. The energy consumption represents 40% to 60% of production cost. Additionally, the cement industry contributes around 5% to 8% of all man-made CO2 emissions. Physiochemical and thermochemical reactions involved in cement kilns are still not well understood because of their complexity. The reactions have a decisive influence on energy consumption, environmental degradation, and the cost of cement production. There are technical difficulties in achieving direct measurements of critical process variables in kiln systems. Furthermore, process simulation is used for design, development, analysis, and optimization of processes, when experimental tests are difficult to conduct. Moreover, there are several models for the purpose of studying the use of alternative fuels, cement clinker burning process, phase chemistry, and physical parameters. Nonetheless, most of them do not address real inefficiency taking place in the processes, equipment, and the overall system. This paper presents parametric study results of the four-stage preheater dry Rotary Kiln System (RKS) with a planetary cooler. The RKS at the Mbeya Cement Company (MCC) in Tanzania is used as a case study. The study investigated the effects of varying the RKS parameters against system behaviour, process operation, environment, and energy consumptions. Necessary data for the modelling of the RKS at the MCC plant were obtained either by daily operational measurements or laboratory analyses. The steady-state simulation model of the RKS was carried out through the Aspen Plus software. The simulation results were successfully validated using real operating data. Predictions from parametric studies suggest that monitoring and regulating exhaust gases could improve combustion efficiency, which, in turn, leads to conserving fuels and lowering production costs. Composition of exhaust gases also depends both on the type of fuel used and the amount of combustion air. The volume of exit flue gases depends on the amount of combustion air and infiltrating air in the RKS. The results obtained from the study suggest a potential of coal saving at a minimum of about ṁcoal=1263 kg·h−1, which approximates to 76,126 tons per year at the current kiln feed of 58,000 kg·h-1. Thus, this translates to a specific energy saving of about 1849.12 kJ·kgcl-1, with relatively higher clinker throughput. In this vein, process modelling provides effective, safe, and economical ways for assessing the performance of the RKS.

PEMBERDAYAAN MASYARAKAT MELALUI PEMANFAATAN LIMBAH SEKAM PADI SEBAGAI BAHAN BAKAR KOMPOR SEKAM YANG RAMAH LINGKUNGAN DI KINALI, PASAMAN BARAT

Kompor merupakan suatu alat yang digunakan masyarakat untuk memasak. Bahan bakar yang digunakan kompor berupa gas elpiji ataupun minyak tanah, gas elpiji. Kelangkaan minyak tanah sudah terjadi mulai dari beberapa tahun yang lalu. Pada saat itu untuk mendapatkan minyak tanah masyarakat harus membayar dengan sangat mahal dan bahkan harus rela melakukan antrian yang sangat panjang untuk mendapatkan beberapa liter minyak tanah. Untuk mengantisipasi hal tersebut maka sudah selayaknya kita memikirkan energi alternatif pengganti minyak tanah. Kegiatan ini bertujuan untuk memberikan solusi dalam mengatasi permasalahan pencemaran limbah sekam padi sebagai energi alternatif yang ramah lingkungan melalui pembuatan kompor sekam untuk penghematan bahan bakar minyak dan gas Kegiatan KKN dilaksanakan pada tanggal 28 Juni hingga 8 Agustus s/d September 2018. Jumlah mahasiswa yang dilibatkan adalah 24 orang. Bentuk kegiatan yang dilakukan berupa penyuluhan, demonstrasi dan pelatihan pembuatan kompor sekam dengan memanfaatkan sekam padi dilakukan oleh dosen Unand dan mahasiswa KKN PPM Unand dengan melibatkan masyarakat di Nagari Kinali Pasaman Barat. Dari kegiatan ini terlihat masyarakat sangat antusias dan mampu membuat kompor sekam dan mengolah limbah sekam padi menjadi bahan bakar kompor sekam tersebut. Disamping itu, kompor sekam dapat digunakan masyarakat untuk memasak dalam mengatasi kelangkaan minyak tanah serta pemanfaatan limbah sekam padi sebagai bahan bakarnya. Kompor dirancang untuk membakar sekam padi menggunakan jumlah udara terbatas untuk pembakaran yang menghasilkan api bercahaya biru, yang hampir mirip dengan kompor LPG. Dari kegiatan ini diharapkan masyarakat dapat mengoptimalkan penggunaan kompor sekam dalam kehidupan sehari-hari untuk menghemat biaya dan mengatasi kelangkaan dan mahalnya gas elpiji maupun minyak tanah serta mengatasi pencemaran lingkungan dari limbah sekam.

Woodchip Combustion Process Quality and the Amount of Combustion Air

The paper deals with woodchip combustion from the point of view of burning control. Control system has to ensure optimal ratio of fuel and air. There are a lot of conditions to satisfy optimization of woodchip burning. The contribution of the paper is concentrated on confirmation of fact that primary/secondary air relation can significantly reduce the among of unburned carbon monoxide.

저열량 바이오매스 합성가스의 혼소특성

Although biomass syngas is very low calorific gas, it is utilized by means of dual fuel combustion technology in the fields of industrial furnace and boiler as a substitute oil technology. The basic structure of duel fuel combustion burner is designed so that low caloric gas fuel is supplied around an oil burner in the middle. In the present study, three types of mixing burners were manufactured to conduct performance experiment. Low caloric gas was evenly distributed around the oil burner and the method of changing the angle of gas nozzle was applied. CO generation decreased according to the increase of the amount of air for combustion. In addition, the shapes and colors of flame changed according to the proportions of gas and oil used. Remained flame after combustion was from the lack of atomization at the exit of oil burner. Although it was difficult to maintain the optimum air ratio due to different required air ratio for oil and syngas, stable combustion was able to maintained within excess oxygen concentration of 4.7~8.2%. From this study, it was shown that the oil atomization at the exit of fuel oil nozzle was promoted by the increased rate of syngas combustion and the CO concentration in flue gas lower than only fuel oil combustion.

Formation of particulate matter depending on the amount of combustion air

The paper deals about the impact of the amount of combustion air and its allocation between primary, secondary and tertiary entrance to the combustion process. Concentration of emission and heat power of source can be affected by several factors. One of the important factors is the amount of combustion air and its allocation to primary and secondary combustion air. The paper includes a proposal of experimental equipment, where the effect of the amount of combustion air to formation emission was examined. The measurement methodology, measured results and analysis of the achievements are also described.

Experimental Studies on Unsteady Lateral Blowing on NACA 0012

T HE initial study of steady lateral blowing was conducted by Dixon in 1969 [1]. The mechanism of this concept is analogous to the flow over slender delta wing platforms, which produces a leading-edge vortex and nonlinear lift curves. Steady lateral blowing might be thought of as providing the sweep effects such as those of the delta wings, for which the effective sweep is a function of the jet momentum. The lateral blowing jet can be described in terms of the chordwise position along the airfoil section, the nozzle height, and the nozzle size. Dixon et al. [2] andClarke [3] suggested that the best vertical nozzle positionmay be a function of the nozzle diameter and that the jet from a nozzle placed too near the airfoil surface may have a deleterious effect on the flow over the airfoil. Wong and Kontis [4] performed a comprehensive study on the steady spanwise blowing on a NACA 0012 airfoil section. The force measurements showed that the lift coefficient increasedwhen the steady lateral blowingwas applied, and the most effective blowing location was found to be at x=c 0:25 (x is the chordwise location and c is the airfoil chord), because the lift augmentation ratio Cl=C was always above one for all positive angles of attack [ Cl is the increment in the lift coefficient due to blowing, andC is the blowing momentum coefficient; the definition ofC is shown inEq. (1)].However, largemomentumwas required to generate the lift enhancement on the airfoil and this became a major issue in the effectiveness of blowing. As a consequence, Meyer and Seginer [5] performed some initial tests for generating the same lift increase using lower momentum through pulsed blowing. One of the main disadvantages of lateral blowing is due to the fact that air for blowing is bled from the compressor stage of the engine. This reduces the amount of air for combustion, hence reducing thrust. Unsteady blowing provides the beneficial effect of reducing the mass-flow requirement from the engine. Another adverse effect of the technology arises from the need to install plumbing, control valves, regulators, oscillators, etc., to supply and control the compressed air from the engine. This adds weight to the aircraft, and a higher lift is required. C thrust

Effects of air excess control in a heat storage solid fuel-fired household furnace

Due to a significant increase in electricity prices during the last decade and insufficient production capacity of the electric power industry in Serbia, many households that are currently using electric heat storage furnaces for heating have been forced to find an alternative solution for heating. A possible solution is replacing electric heating appliances with similar solid fuel-fired ones. Existing solid fuel-fired furnaces are often unsatisfactory with respect to their efficiencies and flue gas emissions. A prototype of a new concept of heat storage, solid fuel-fired furnace has been developed to meet these growing needs, providing electricity saving together with considerable environmental benefits. In order to examine furnace performance, efficiency and environmental aspects, and to assess the influence of air excess control in the furnace on the efficiency and flue gas emissions, numerous experimental tests were conducted. The amount of combustion air, the flue gas flow rate and the fuel feeding regime have been adjusted in order to keep the flue gas oxygen content in a relatively narrow range, thus obtaining controlled combustion conditions and, correspondingly, lower carbon monoxide emission and higher furnace efficiency. In this way, the furnace was made able to respond to the changes in heating needs, fuel quality and other parameters, which is considered to be advantageous in comparison with similar solid-fuel fired furnaces.

Reduction of carbon monoxide emission from a solid-fuel thermo-accumulation furnace

Many households in Serbia, using electric thermo-accumulation furnaces for heating, have been forced to find an alternative solution, due to a significant increase in electricity prices during the last decade. A possible solution is replacing electric heating appliances with the solid fuel-fired ones. A prototype of a new concept of thermo-accumulation solid fuel-fired furnace has been developed to meet these growing needs, providing electricity saving together with considerable environmental benefits. Two strategies for reduction of carbon monoxide emission are examined in the paper: application of Pt/Al2O3 catalyst, in the form of 3 ? 0.3 mm spheres, providing further combustion of flue gases within the furnace, as well as an additional emission reduction by means of the air excess control. Experimental investigations of the catalyst influence on the conversion of carbon monoxide have been done for different operation regimes and positions of the catalyst. The paper presents selected results regarding carbon monoxide emission during wood and coal combustion. Investigations suggest a considerable effect of the catalyst and a strong influence of the catalyst position within the furnace to carbon monoxide emission reduction. In addition, experimental tests have been conducted to asses the effect of the air excess control in the furnace on carbon monoxide emission. The amount of combustion air, the flue gas flow rate, and the fuel feeding regime have been adjusted in order to keep the flue gas oxygen content in a relatively narrow range, thus obtaining controlled combustion conditions and lower carbon monoxide emission. In this way, the furnace has been made able to respond to the changes in heating needs, fuel quality and other parameters, which is advantageous in comparison with similar solid-fuel fired furnaces. .

Cement manufacturing using alternative fuels and the advantages of process modelling

Energy costs and environmental standards encouraged cement manufacturers world-wide to evaluate to what extent conventional fuels can be replaced by alternative fuels, i.e., processed waste materials. Clinker burning is well suited for various alternative fuels. In order select a suitable alternative fuel, a commercial modelling tool (ASPEN PLUS®) is used to model the four-stage pre-heater kiln system of a full-scale cement plant (clinker production ∼2900 tons/day), using petcoke as fuel. The goal is to optimise process control and alternative fuel consumption, while maintaining clinker product quality. Calculations with varying amounts of different fuels are compared with a reference case. The dependence of process performance on the amount of combustion air is clearly demonstrated and the energy demand of the process could be predicted for varying fuel mixes.

Calculation of three-dimensional flow and pressure fields in cracking furnaces

The simulation of correct flow and pressure fields in the radiation section of industrial thermal cracking furnaces is of practical interest since the amount of combustion air taken in by the burners in general is partly determined by the pressure field. For such engineering purposes often a (practical) simplified numerical treatment of the viscous terms in the flow equations is used to reduce the computational cost. It is shown that the interaction between such a simplified numerical treatment of the viscous terms and the alignment of the cell interfaces with the coordinate system can result in an erroneous (non-physical) calculation of the pressure field. This alignment problem is predominantly present when using a semi non-structured prismatic grid to solve the flow equations. Using a fully non-structured tetrahedral grid avoids this problem because of the random orientation of the cell interfaces for this type of grid. This is confirmed by assuring that the calculation results are independent with respect to grid refinement. At the same time the influence of the presence of the reactor tubes on the velocity field inside the furnace is examined.

Analysis of Wood Combustion Based on the First and Second Laws of Thermodynamics

Wood is a highly flexible fuel which can be used in a variety of ways for energy generation. Direct combustion of wood is the oldest method of utilization of this renewable energy source. This paper presents an analysis of wood combustion based on the first and second laws of thermodynamics, using a computer program developed for this study. Since the moisture content of the available wood fuels vary over a wide range, special attention is given to the effects of moisture content on the exergy and energy content of the wood. Because of the wide variation in particle size and moisture content of the wood fuels, different types of combustion systems have been designed and are utilized in industry. Each combustion system uses a certain amount of combustion air and is designed for a certain range of combustion air temperatures and wood fuel moisture contents. The effects of these variables on wood combustion and the efficiencies of the process have been studied and are presented in this paper. To point out the importance and differences between efficiencies that are commonly used, several efficiencies based on the first and the second laws of the thermodynamics are calculated and compared. Based on the results presented in this report, it is concluded that, over the range of variables studied, the most efficient conditions for wood combustion can be achieved by using the minimum amount of excess air at highest permissible temperature. It is also concluded that the lower moisture contents result in higher combustion efficiencies.