scholarly journals Investigation of the co-firing of natural gas and RDF in a model combustion chamber**

2021 ◽  
pp. 67-73
Author(s):  
Serhii Kobzar ◽  
Olexandr Topal ◽  
Liudmyla Haponych ◽  
Iryna Golenko
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Solid Phase ◽  
Calorific Value ◽  
Hot Water ◽  
Heat Output ◽  
Power Sector ◽  
Ecological Requirements ◽  
Hot Water Supply ◽  
Gas Component

The production and utilization of fuel derived from municipal solid waste (RDF/SFR) is an effective method for saving organic fuel and decreasing emissions of harmful substances and greenhouse gases at landfill and refuse dumps. Ukraine has a potential for the production of 1.5–2 million tons of RDF/SFR with a calorific value of 10–25 MJ/kg annually. In the case of involving these fuels to power sector, about 2500 GW-h of electricity and 4500 GW-h of heat can be produced annually. One of the promising variants to involve RDF/SFR to power sector is their combustion, including co-firing with natural gas, aimed at the production of heat and electricity, in particular, using the existing boilers of small and middle steam capacity in compliance with stringent ecological requirements (Directive 2010/75/EU etc.). For performing this investigation, we chose a GMP-16 gas-and-oil-fired burner, mounted into a cylindrical combustion chamber. The gas-and-oil-fired hot-water boilers of KVGM grade, designed for heating and hot water supply, are equipped with burners of this type. In computer modeling, we determined the influence of RDF additions on the co-firing with natural gas for a given geometry of the combustion chamber components (with a burner of 18.6 MW heat output). We obtained calculated dependences of temperatures, velocities, distributions of gas component concentrations, carbon remained in the solid phase, as well as the concentrations of nitrogen oxides and carbon monoxide over the combustion chamber. According to preliminary assessments, we established that additions of up to 20% RDF/SFR (by heat at input) in their co-firing with natural gas will not change substantially the technical and ecological parameters in operation of the combustion chamber.

Reliable and safe heat supply of residential buildings in transitional conditions with independent connection of the heating system

2021 ◽  
Vol 14 (1) ◽  
pp. 27-33
Author(s):  
O. D. Samarin
Keyword(s):  
Water Supply ◽  
Heat Exchangers ◽  
Heat Supply ◽  
Residential Buildings ◽  
Structural Characteristics ◽  
Heating System ◽  
Hot Water ◽  
Heat Output ◽  
Outdoor Air ◽  
Hot Water Supply

The arrangement for heat supply of residential buildings with indirect connection to external heating systems is considered, providing reliability of heat input and required comfort in case of cold snaps after the official end of the heating season or before its beginning by supplying water from the return main of the heating system downstream the hot water supply heat exchangers. The calculations have been made to determine the amount of the main components of heat balance of a residential building on an example of one of standard projects being currently used in the climatic conditions of Moscow, subject to the structural characteristics of the building and its occupancy level. It is established that the actual heat output of the heating system when using the system of chilled water downstream the hot water supply heat exchangers as a heat source enables to main-tain an indoor temperature required for safe living conditions with the average daily outdoor air temperature above +2°C, the heat gain from solar radiation being moderate. It is proven that, tak-ing into account the thermal stability of the enclosing structures, the daily flow rate fluctuations do not significantly affect the stability of the temperature conditions of residential buildings or the comfort of their indoor microclimate at high outdoor air temperatures. It is noted that, in terms of reliability of heat supply of the main group of residential buildings and ensuring the life safety, the proposed arrangement is not inferior to the standard two-stage arrangement of connection of DHW heat exchangers with restriction of the total consumption of delivery water and with the associated regulation of heat supply for DHW, heating and ventilation. It is shown that the use of this arrangement involves virtually no extra costs, provides hydraulic resistance of the heating system and ensures a system-wide effect in the form of higher electricity generation at thermal consumption when using cogeneration.

CFD Simulation of a Microturbine Annular Combustion Chamber Fuelled With Methane and Biomass Pyrolysis Syngas: Preliminary Results

2009 ◽  
Author(s):  
Francesco Fantozzi ◽  
Paolo Laranci ◽  
Michele Bianchi ◽  
Andrea De Pascale ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Calorific Value ◽  
Methane Combustion ◽  
Pollutant Emissions ◽  
Preliminary Results

Micro gas turbines could be profitably used, for distributed energy production, also exploiting low calorific value biomass-derived fuels, obtained by means of integrated pyrolysis and/or gasification processes. These synthesis gases show significant differences with respect to natural gas (in terms of composition, low calorific value, hydrogen content, tar and particulate matter content) that may turn into ignition problems, combustion instabilities, difficulties in emission control and fouling. CFD simulation of the combustion chamber is a key instrument to identify main criticalities arising when using these gases, in order to modify existing geometries and to develop new generation combustion chambers for use with low calorific value gases. This paper describes the numerical activity carried out to analyze the combustion process occurring inside an existing microturbine annular combustor. A CFD study of the combustion process performed with different computational codes is introduced and some preliminary results are reported in the paper. A comparison of results obtained with the different codes is provided, for the reference case of methane combustion. A first evaluation of the pollutant emissions and a comparison with the available experimental data is also provided in the paper, showing in particular a good matching of experimental data on NOx emissions at different load conditions. Moreover, the carried out investigation concerns the case of operation with a syngas fuel derived from pyrolysis of biomass and finally the case of syngas and natural gas co-firing. This combustion condition is simulated with a simple reduced chemical kinetic scheme, in order to assess only the key issues rising with this fuel in comparison with the case of methane combustion. The analysis shows that in case of syngas operation the combustor internal temperature hot spots are reduced and the primary zone flame tends to stabilize closer to the injector, with possible implications on the emission release.

scholarly journals EXPERIENCE OF DEVELOPMENT, IMPLEMENTATION AND MODERNIZATION OF HOT WATER SUPPLY BOILERS WITH DUAL-SCREENS AND THE SLOT BOTTOM BURNERS

2019 ◽  
pp. 17-26
Author(s):  
E.M. Lavrentsov ◽  
I.Ya. Sigal ◽  
A.V. Smikhula ◽  
E.P. Dombrowska ◽  
O.S. Kernazhytska ◽  
...  
Keyword(s):  
Water Supply ◽  
Nitrogen Oxide ◽  
Hot Water ◽  
Furnace Chamber ◽  
Heat Output ◽  
Nitrogen Oxide Emissions ◽  
Eu Directive ◽  
Hot Water Supply ◽  
Cis Countries ◽  
Technical Solutions

The increases service life of gas hot water supply boilers with uniform heat supply along of the depth (width) of the combustion chamber for more than 40 years, by using of slot bottom burners was shown. While reducing nitrogen oxide emissions by using of dual-screens its can significantly increase the heat stress of the furnace, the volume of the furnace chamber and the temperature of the flue gases had left unchanged. The boilers with a capacity of 1–10 MW, with the above technical design solutions of the Gas Institute of the NAS of Ukraine, with a total heat capacity of more than 60 GW, continue to be operated and produce in Ukraine and the CIS countries. Installed boilers relatively nitrogen oxide emissions comply with new EU directive (EU) 2015/2193. The using of gas slot bottom burners can reduce nitrogen oxide emissions by approximately 15 % compared to the basic factory vortex types GMG or GMGB installed on many boilers was shown. A project for the reconstruction of boilers TVG-8 (TVG-8M) and KVG-7.56 with an increase in convective surface area by replacing the factory pipe 28x3 mm with 32x3 mm had developed. Using the improved slot bottom burners in particular equipped with calibrated nozzles for precise dosing of natural gas into the air was envisaged. As a result of a research test of the reconstructed boilers for 3-5 years these technical solutions could increase the energy efficiency of existing TVG and KVG boilers up to the current European level —94–95 at rated heat output was shown. Ref.18, Fig.4, Tab. 5.

Evaluation of Ethanol as a Fuel for Gas Turbines

2013 ◽  
Author(s):  
Ignacio Carvajal-Mariscal ◽  
Florencio Sanchez-Silva ◽  
Rodrigo Jaramillo-Martínez ◽  
Georgiy Polupan
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Calorific Value ◽  
Convincing Evidence ◽  
Design Data ◽  
Fuel Ratio ◽  
Different Temperatures ◽  
A Minor ◽  
Thermodynamic Basis

In this paper, the results of the evaluation of using ethanol in a GE 61B gas turbine are presented. For better understanding, combustion analysis for natural gas was performed as a comparison point, calculating fuel and air requirements at the entrance and exit of the combustion chamber, obtaining the principal emissions for both fuels at different temperatures and relationships air-fuel. Using design data taken from the manufacturer website, the four main processes of a complete Joule-Brayton cycle were calculated. In that way, the results were used as a thermodynamic basis in this work. Focus on the combustion turbine, setting the temperature at the entrance of the combustion chamber and varying the temperature at turbine inlet. Afterward, using the temperatures resulted by the calculations, stoichiometric air-fuel ratio and mole fractions were found. Finally, varying air-fuel ratio at diverse mixtures, there were obtained the emissions for both fuels. As results, there were obtained the fuel requirements for natural gas and ethanol, finding that for ethanol, due to its lower calorific value, the amount of fuel is higher in order to obtain the required temperature. In terms of emissions, there was no convincing evidence that ethanol represents a minor emission source than natural gas; therefore, it could be a good substitute of natural gas in those countries were ethanol is produced.

Effect of Chemical Hythane Composition on Pressure in Combustion Chamber of Engine

2019 ◽  
pp. 36-42
Author(s):  
A. P. Shaikin ◽  
I. R. Galiev
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Power Plants ◽  
Engine Speed ◽  
Combustion Engine ◽  
Fuel Mixture ◽  
Maximum Pressure ◽  
Chamber Volume ◽  
Excess Air ◽  
Scientific Papers

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.

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