scholarly journals Gas Combustion Efficiency Enhancement: Application Study of Intense Elestrostatic Field

2019 ◽  
Vol 56 (4) ◽  
pp. 3-16
Author(s):  
O. Krickis ◽  
N. Zeltins
Keyword(s):  
Electrostatic Field ◽  
Flue Gas ◽  
Combustion Process ◽  
Field Application ◽  
Process Efficiency ◽  
Simultaneous Increase ◽  
Efficiency Enhancement ◽  
Gas Temperature ◽  
Gas Combustion ◽  
The Impact

Abstract A number of international, European Union and Latvian legislative acts have been developed, which regulate the efficiency of gas combustion plants and greenhouse gas emissions in the atmosphere. These legislative acts require the development of new scientifically efficient methods for gas optimal combustion with a minor impact on the environment. In order to achieve such a goal, different methods can be used, but the most efficient is an intensive electrostatic field application to control combustion and harmful emission formation in premixed flames. In the framework of the current study, the authors developed a hybrid burner, which allowed generating an intensive electrostatic field with intensity of more than 1000 kV/m. The study also investigated the impact of such a field on the formation of harmful emissions, including CO2 and flue gas temperature. The empirical results showed that an intensive DC electrostatic field generated inside of the burner had an impact on the flame shape, CO2, NOx emissions and flue gas temperature. In its turn, by applying an intensive pulsating electrostatic field (multivariable experiment) it was possible to achieve the reduction in NOx, CO emissions with a simultaneous increase in flue gas temperature, which was related to combustion process efficiency enhancement.

The Partition Period of Thermodynamic Calculation and the Numerical Simulation for Lignite Blended Supercritical Boiler

2014 ◽  
Vol 1030-1032 ◽  
pp. 648-652
Author(s):  
Cai Ying Ban ◽  
Xu Ao Lu ◽  
Jian Meng Yang ◽  
Xu Ran ◽  
Feng Ying Liang
Keyword(s):  
Numerical Simulation ◽  
Flue Gas ◽  
Thermodynamic Calculation ◽  
Heat Load ◽  
Combustion Process ◽  
Heating Surface ◽  
Gas Temperature ◽  
Boiler Furnace ◽  
Geometry Model ◽  
The Impact

The purpose of this paper is to study the impact of furnace temperature and load after blending in lignite, based on CFD software FLUENT-6.3,this paper choose the appropriate geometry model and the physical and mathematical models, and numerical simulation of the different conditions 600MW supercritical once-through boiler blending lignite furnace combustion process is curried out. And through a 600MW supercritical coal-fired boiler furnace lignite blended performed sections thermodynamic calculation under different conditions, worked out the furnace flue gas temperature, CO, CO2concentration distribute trend and radiant heat each section surface heat load conditions. The specific amount were blended with 5%, 10%, 15%, 20% were not dried lignite and dried lignite 20% after five conditions. And obtained a conclusion is the temperature and radiation heating surface flue gas heat load in the overall trend under the various conditions.

scholarly journals Q-Learning Neural Controller for Steam Generator Station in Micro Cogeneration Systems

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5334
Author(s):  
Krzysztof Lalik ◽  
Mateusz Kozek ◽  
Szymon Podlasek ◽  
Rafał Figaj ◽  
Paweł Gut
Keyword(s):  
Numerical Model ◽  
Control Systems ◽  
Steam Generator ◽  
Full Range ◽  
Combustion Process ◽  
Liquid Fuels ◽  
Control Algorithms ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
The Impact

This article presents the results of the optimization of steam generator control systems powered by mixtures of liquid fuels containing biofuels. The numerical model was based on the results of experimental research of steam generator operation in an open system. The numerical model is used to build control algorithms that improve performance, increase efficiency, reduce fuel consumption and increase safety in the full range of operation of the steam generator and the cogeneration system of which it is a component. In this research, the following parameters were monitored: temperature and pressure of the circulating medium, exhaust gas temperature, oxygen content in exhaust gas, percentage control of oil burner power. Two methods of controlling the steam generator were proposed: the classic one, using the PID regulator, and the advanced one, using artificial neural networks. The work shows how the model is adapted to the real system and the impact of the control algorithms on the efficiency of the combustion process. The example is considered for the implementation of advanced control systems in micro-, small- and medium-power cogeneration and trigeneration systems in order to improve their final efficiency and increase the profitability of implementation.

Waste Combustion Technology and Air Emission Control Developments by Fisia Babcock Environment

2011 ◽  
Author(s):  
Jens Sohnemann ◽  
Walter Scha¨fers ◽  
Armin Main
Keyword(s):  
Flue Gas ◽  
Combustion Process ◽  
Great Majority ◽  
Optimum Process ◽  
Cleaning Process ◽  
Gas Temperature ◽  
Flash Evaporation ◽  
Limit Values ◽  
Gas Cleaning ◽  
Secondary Air

The efforts for reducing the emissions into the atmosphere start already in the furnace and are completed by an effective flue gas cleaning system. This implies the necessity for design developments of key components for a modern EfW plant. For the core component of the firing system — the grate — Fisia Babcock Environment (FBE) is using forward moving grates as well as roller grates. The moving grate, which is used in the great majority of all our plants, has specific characteristics for providing uniform combustion and optimal burnout. These include, amongst others: - Uniform air supply by means of specific grate bar geometry. - Two grate steps in direction of waste transport for optimum burnout. - Flexible adaptation of the combustion process to the respective conditions and requirements by zone-specific air distribution and transport velocity of waste on grate. - Combustion control adapted to the specific plant for ensuring a consistent combustion process and production of energy. In addition to these features influencing the emissions the moving grate exhibits also specific characteristics regarding the mechanical aspects allowing low-maintenance and reliable operation. For optimum flue gas burnout a good oxygen distribution after leaving the combustion zone is required. For ensuring this, the injection of secondary air is designed to produce a double-swirl, developed by FBE. Final reduction of the nitrogen constituents NO and NO2 to the stipulated emission value is achieved by the SNCR process. As well in this respect, there is a great amount of experience available. Besides these measures regarding the combustion process, this paper also reports about flue gas cleaning systems. In this field the FBE CIRCUSORB® process is presented and compared with the known dry absorption process. CIRCUSORB® is a lime-based flue gas cleaning process with continuous recirculation of the moistened reaction product and simultaneous addition of fresh hydrated lime. The flue gas temperature downstream of the economizer can be selected very low and permits in this way maximized utilization of the energy. The evaporation of the moisture from the reaction product (flash evaporation) effects final cooling down of the flue gas to optimum process temperature and improves at the same time SO2 separation. This reduces the technical investment required for the flue gas cleaning process. The total of all measures taken and the robust design of all components permit economical plant operation while complying with the stipulated emission limit values.

Applying the X-Ratio Correction to Calculated Air Heater Efficiency: An Alternate Method

2010 ◽  
Author(s):  
David C. McLaughlin ◽  
Joseph R. Nasal
Keyword(s):  
Heat Capacity ◽  
Heat Exchanger ◽  
Correction Factor ◽  
Mass Flow ◽  
Flue Gas ◽  
Correction Method ◽  
Gas Temperature ◽  
Original Design ◽  
Air Heater ◽  
The Impact

ASME PTC 4.3 on testing Air Heaters provides guidance for the calculation of gas-side efficiency as a measure of air heater performance. This code also provides for calculation of air heater X-ratio (XR), which is the ratio of the heat capacity (mass flow times specific heat capacity) of the air flowing through the heater to that of the flue gas. The code acknowledges the impact of XR on air heater efficiency, and dictates that the gas temperature leaving the air heater (and hence, air heater efficiency) be corrected for deviation from design XR by the use of “appropriate design correction curves” [1]. Unfortunately, such curves are rare, and therefore this important correction is usually ignored in routine air heater test calculations by power plant testing personnel, resulting in an incorrect calculation of air heater efficiency. This is particularly true for balanced draft boilers burning coal that are aged and have a significant amount of air leakage into the boiler setting. On these boilers, the ratio of combustion flue gas mass flow to combustion air mass flow is changed significantly from the original design, and therefore applying an XR correction factor is essential to calculating and reporting accurate air heater efficiency. This paper presents a method to calculate and correct for a deviation from design X-ratio based on standard heat exchanger analysis techniques, namely the ε-NTU method, which utilizes the concept of heat exchanger effectiveness (ε). A solution that results in applying the ratio of the design to actual XR’s as the correction factor is developed. The paper also provides empirical data from testing on a coal-fired boiler to validate the alternate correction method.

scholarly journals Assessment of the Impact of Modification of Calcium Sorbents and the Possibility of Their Use in Desulfurization for Oxy-Fuel Combustion Process

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1284
Author(s):  
Michał Wichliński ◽  
Renata Włodarczyk
Keyword(s):  
Flue Gas ◽  
Mercury Porosimetry ◽  
Combustion Process ◽  
Flue Gas Desulfurization ◽  
Sorption Coefficient ◽  
Lithium Compounds ◽  
Process Modification ◽  
The Absolute ◽  
Reactivity Coefficient ◽  
The Impact

The paper describes the possibilities of simple and effective modification of calcium sorbents used for flue gas desulfurization with a size between of 125–250 µm. The additives to the sorbents in the amount of 0.5% and 1.0% were inorganic sodium and lithium compounds. The research on the reactivity of sorbents was analyzed in the process of simultaneous calcination and sulfation at the temperature of 850 °C. The type of Na+ or Li+ cations and the inorganic salt anions have an influence on the modification of calcium sorbents in order to improve the efficiency of the calcination and sulfation process. Modification of calcium sorbents by adding inorganic sodium and lithium compounds, regardless of the amount, changes the reactivity coefficient RI [mol/mol] and the absolute sorption coefficient CI [g S/kg sorbent]. In the case of inorganic sodium salt (Additive 1), regardless of the amount of modifier added, there was a visible improvement in the reactivity of the sorbent: 1.0% of the additive caused an increase in the RI coefficient in relation to the raw sorbent by over 14%, and in the case of the CI coefficient by over 24%. Additional research was the analysis of the limestone behavior mechanism during the simultaneous calcination and sulfation (SCS) process under conditions of elevated temperature and with variable CO2 and O2 contents in the flue gas. The behavior of sorbents with a size distribution of 125–250 µm was assessed on the basis of the change in mass of the samples by determining the reactivity coefficient RI, [mol/mol] and the absolute sorption coefficient CI, [g S/kg sorbent]. Using the mercury porosimetry technique, the change in sorbent porosity in the subsequent stages of the simultaneous calcination and sulfation process was investigated. The process was carried out in the temperature range corresponding to the oxy-combustion (i.e., from 850 °C to 1000 °C).

scholarly journals Investigations of combustion process in combined cooker-boiler fired on solid fuels

2006 ◽  
Vol 10 (4) ◽  
pp. 121-130
Author(s):  
Dragoslava Stojiljkovic ◽  
Vladimir Jovanovic ◽  
Milan Radovanovic ◽  
Nebojsa Manic ◽  
Ivo Radulovic
Keyword(s):  
Flue Gas ◽  
Combustion Process ◽  
Solid Fuels ◽  
Gas Temperature ◽  
Weight Changes ◽  
Complete Combustion ◽  
Air Supply ◽  
Class 1 ◽  
Secondary Air ◽  
Co Emission

The aim of the investigation was to make some reconstructions on the existing stove used for cooking and baking and to obtain the combined cooker-boiler which will fulfill the demands of European standard EN 12815. Implementation of modern scientific achievements in the field of combustion on stoves and furnaces fired on solid fuels was used. During the investigations four various constructions were made with different fresh air inlet and secondary air supply with the intention to obtain more complete combustion with increased efficiency and reduced CO emission. Three different fuels were used: firewood, coal, and wood briquette. A numerous parameters were measured: fuel weight changes during the combustion process, temperature of inlet and outlet water, flue gas composition (O2, CO, SO2, CO2, NOx), flue gas temperature, ash quantity etc. The result of the investigations is the stove with the efficiency of more than 75% - boiler Class 1 (according EN 12815) and CO emission of about 1% v/v. The results obtained during the measurements were used as parameters for modeling of combustion process. .

Flue Gas Recirculation in a Gas Turbine: Impact on Performance and Operational Behavior

2011 ◽  
Author(s):  
Frank Sander ◽  
Richard Carroni ◽  
Stefan Rofka ◽  
Eribert Benz
Keyword(s):  
Power Plant ◽  
Co2 Capture ◽  
Flue Gas ◽  
Power Plants ◽  
Combustion Process ◽  
Combined Cycle ◽  
Flue Gas Recirculation ◽  
Overall Performance ◽  
Gas Recirculation ◽  
The Impact

The rigorous reduction of greenhouse gas emissions in the upcoming decades is only achievable with contribution from the following strategies: production efficiency, demand reduction of energy and carbon dioxide (CO2) capture from fossil fueled power plants. Since fossil fueled power plants contribute largely to the overall global greenhouse gas emissions (> 25% [1]), it is worthwhile to capture and store the produced CO2 from those power generation processes. For natural-gas-fired power plants, post-combustion CO2 capture is the most mature technology for low emissions power plants. The capture of CO2 is achieved by chemical absorption of CO2 from the exhaust gas of the power plant. Compared to coal fired power plants, an advantage of applying CO2 capture to a natural-gas-fired combined cycle power plant (CCPP) is that the reference cycle (without CO2 capture) achieves a high net efficiency. This far outweighs the drawback of the lower CO2 concentration in the exhaust. Flue Gas Recirculation (FGR) means that flue gas after the HRSG is partially cooled down and then fed back to the GT intake. In this context FGR is beneficial because the concentration of CO2 can be significantly increased, the volumetric flow to the CO2 capture unit will be reduced, and the overall performance of the CCPP with CO2 capture is increased. In this work the impact of FGR on both the Gas Turbine (GT) and the Combined Cycle Power Plant (CCPP) is investigated and analyzed. In addition, the impact of FGR for a CCPP with and without CO2 capture is investigated. The fraction of flue gas that is recirculated back to the GT, need further to be cooled, before it is mixed with ambient air. Sensitivity studies on flue gas recirculation ratio and temperature are conducted. Both parameters affect the GT with respect to change in composition of working fluid, the relative humidity at the compressor inlet, and the impact on overall performance on both GT and CCPP. The conditions at the inlet of the compressor also determine how the GT and water/steam cycle are impacted separately due to FGR. For the combustion system the air/fuel-ratio (AFR) is an important parameter to show the impact of FGR on the combustion process. The AFR indicates how close the combustion process operates to stoichiometric (or technical) limit for complete combustion. The lower the AFR, the closer operates the combustion process to the stoichiometric limit. Furthermore, the impact on existing operational limitations and the operational behavior in general are investigated and discussed in context of an operation concept for a GT with FGR.

CFD Analysis of Temperature Distribution in Can-Type Combustor Firing Synthetic Gas

2013 ◽  
Vol 393 ◽  
pp. 741-746 ◽  
Author(s):  
Hasril Hasini ◽  
Norshah Hafeez Shuaib ◽  
Wan Ahmad Fahmi Wan Abdullah
Keyword(s):  
Temperature Distribution ◽  
Natural Gas ◽  
Flue Gas ◽  
Flame Temperature ◽  
Base Case ◽  
Cfd Analysis ◽  
Gas Temperature ◽  
Gas Combustion ◽  
Synthetic Gas ◽  
Natural Gas Combustion

This paper presents CFD analysis of the effect of syngas combustion in a full scale gas turbine combustor with specific emphasis given to the flame and flue gas temperature distribution. A base case solution was first established using conventional natural gas combustion. Actual operating boundary conditions such as swirl, diffusion and fuel mass flow were imposed on the model. The simulation result is validated with the flame temperature of typical natural gas combustion. Result from flow and combustion calculation shows reasonable trend of the swirl mixing effect. The maximum flame temperature was found to be the highest for syngas with the highest H2/CO ratio. However, the flue gas temperature was found to be approximately identical for all cases. The prediction of temperature distribution in the combustor would enable further estimation of pollutant species such as CO2and NOxin complex regions within the combustor.

Pressurised Oxy-Coal Combustion Rankine-Cycle for Future Zero Emission Power Plants: Process Design and Energy Analysis

2008 ◽  
Author(s):  
Marco Gazzino ◽  
Giancarlo Benelli
Keyword(s):  
Flue Gas ◽  
Process Design ◽  
Energy Analysis ◽  
Combustion Process ◽  
Rankine Cycle ◽  
Air Separation ◽  
Regenerative Heat ◽  
Separation Unit ◽  
High Heat Transfer ◽  
The Impact

This paper presents the process design and the energy analysis for a coal-fired power plant based on pressurised oxycoal combustion and including carbon capture technologies. A combustion technology performing a pressurised combustion of coal in an atmosphere of O2/CO2/H2O and including flue gases recycling has been selected. Combustion and steam production occur in separated equipments and the combustor’s design allows achieving high ash removal efficiency. The Rankine cycle has been chosen as the most viable thermodynamic cycle in a short-term scenario. Oxygen required by the combustion process is supplied by a cryogenic Air Separation Unit (ASU) and a double-reheat ultrasupercritical cycle is employed with main steam conditions of 250bar/605°C and reheat steam temperatures of 605°C/620°C. All choices related to thermal cycle selection and process design have been conducted upon the principle of feasibility and reliability. In order to increase net plant efficiency both sensible and latent heat is recovered from the flue gas stream before entering the purification and compression section. By operating in pressure it becomes possible to recover a larger amount of heat than in the atmospheric case. As a result, all low pressure steam bleedings and the corresponding regenerative heat exchangers can be eliminated. Process simulation is carried out in the paper and the expected efficiency is evaluated, as well as other cycle performance parameters. Since a relevant benefit may arise from the combustion of cheap coals, the impact of burning high-ash content and low ash-fusion-temperature coals is assessed. The impact of energy penalties associated to oxygen production and the benefit arising from high heat-transfer coefficients due to the increased pressure of the flue gas are deeply investigated.

High Performance of the CFBC Pilot Plant with CO2 Chemical Absorption by Optimizing the Absorber Parameters

2013 ◽  
Vol 746 ◽  
pp. 3-8
Author(s):  
Cristian Dinca ◽  
Adrian Badea ◽  
Horia Necula
Keyword(s):  
Flue Gas ◽  
High Performance ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Energy Requirement ◽  
Combustion Process ◽  
Process Efficiency ◽  
Solution Temperature ◽  
Fluidized Bed Combustion ◽  
Capture Process

The objective of this paper consists to identify the influence of absorption process temperature and pressure on the energy requirement of the CO2 chemical capture process. The study aimed to reducing CO2 emissions from coal combustion process in the circulating fluidized bed combustion (CFBC). The post-combustion CO2 capture process was analyzed using primary amine MEA in the following conditions: the ratio L/G was varied between 0.45..1.6 kgliquid/kggas keeping constant the flue gas flow and varying the solvent flow between 500 .. 1 600 kg/h. The CO2 capture process efficiency was maintained constant around 90%. For a concentration of 30% MEA in solution, it was observed that when the absorber solution temperature increasing from 32 to 49 °C, the amount of heat required for the solvent regeneration increased from 2.1 to 3.3 GJ/tCO2 according to the solvent pressure and flue gas pressure respectively. On the other hand, for varying the absorber solvent pressure in the range 1.1 .. 2.1 atm, the heat required by the process was not significantly influenced. Considering the same variation of the absorber solvent temperature, the rich loading solvent was increased from 0.43 to 0.57 mol CO2/mol MEA and consequently the MEA capacity of CO2 absorption from 0.3 to 0.422 molCO2/mol MEA.

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