scholarly journals Dual-fuel combustion in a tangential PC-fired boiler of type OP-230 – computational simulations

2018 ◽  
Vol 70 ◽  
pp. 03009
Author(s):  
Przemysław Motyl ◽  
Jan Łach
Keyword(s):  
Combustion Process ◽  
Biomass Gasification ◽  
Agricultural Residues ◽  
Dual Fuel ◽  
Wood Biomass ◽  
Computational Simulations ◽  
Cfd Simulations ◽  
Dual Fuel Combustion ◽  
Firing Technology ◽  
Air Staging

Syngas co-firing in coal fired boilers can be one of the prospective technologies which may help to retrofit some of still functioning older boilers. This study focuses on the results of CFD simulations of wood biomass-derived syngas co-firing with coal in an older mid-sized tangential PC-fired boiler of type OP-230. The design and the implementation of the combustion process predispose the boiler to the connection with the biomass gasifier in which low calorific syngas from solid raw biomass gasification can be produced and next used as a supplemental fuel in the coal furnace. The simulations were performed to predict the influence of the improvement of the air staging via the dual-fuel technique based on the indirect co-firing technology on both the reductions in NOx emissions relative to the baseline (no syngas) and the residence time of syngas particles in a zone with the temperature higher than 1123K. This way one can determine whether the boiler can be recommended to indirect co-firing of syngas derived from agricultural residues biomass or SRF gasification containing such troublesome components as chlorine and alkali.

scholarly journals A Novel Dual Fuel Reaction Mechanism for Ignition in Natural Gas–Diesel Combustion

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4396 ◽  
Author(s):  
Sebastian Schuh ◽  
Jens Frühhaber ◽  
Thomas Lauer ◽  
Franz Winter
Keyword(s):  
Reaction Mechanism ◽  
Natural Gas ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Cfd Simulations ◽  
Surrogate Fuels ◽  
Ignition Delay Times ◽  
Computational Fluid Dynamics Cfd ◽  
Dual Fuel Combustion

In this study, a reaction mechanism is presented that is optimized for the simulation of the dual fuel combustion process using n-heptane and a mixture of methane/propane as surrogate fuels for diesel and natural gas, respectively. By comparing the measured and calculated ignition delay times (IDTs) of different homogeneous methane–propane–n-heptane mixtures, six different n-heptane mechanisms were investigated and evaluated. The selected mechanism was used for computational fluid dynamics (CFD) simulations to calculate the ignition of a diesel spray injected into air and a natural gas–air mixture. The observed deviations between the simulation results and the measurements performed with a rapid compression expansion machine (RCEM) and a combustion vessel motivated the adaptation of the mechanism by adjusting the Arrhenius parameters of individual reactions. For the identification of the reactions suitable for the mechanism adaption, sensitivity and flow analyzes were performed. The adjusted mechanism is able to describe ignition phenomena in the context of natural gas–diesel, i.e., dual fuel combustion.

New Dual-fuel Combustion Process for Passenger Car Engines

MTZ worldwide ◽  
2018 ◽  
Vol 79 (6) ◽  
pp. 60-67
Author(s):  
Florian Sprenger ◽  
Paul Fasching ◽  
Christina Granitz ◽  
Helmut Eichlseder
Keyword(s):  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Passenger Car ◽  
Dual Fuel Combustion

Numerical Simulation of a Large Bore Dual Fuel Marine Engine Using Tabulated Detailed Reaction Mechanisms

2019 ◽  
Author(s):  
Sascha Andree ◽  
Dmitry Goryntsev ◽  
Martin Theile ◽  
Björn Henke ◽  
Karsten Schleef ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Natural Gas ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Start Of Injection ◽  
Flamelet Generated Manifold ◽  
Dual Fuel Combustion

Abstract The simulation of a diesel natural gas dual fuel combustion process is the topic of this paper. Based on a detailed chemical reaction mechanism, which was applied for such a dual fuel combustion, the complete internal combustion engine process was simulated. Two single fuel combustion reaction mechanisms from literature were merged, to consider the simultaneous reaction paths of diesel and natural gas. N-heptane was chosen as a surrogate for diesel. The chemical reaction mechanisms are solved by applying a tabulation method using the software tool AVL Tabkin™. In combination with a Flamelet Generated Manifold (FGM) combustion model, this leads to a reduction of computational effort compared to a direct solving of the reaction mechanism, because of a decoupling of chemistry and flow calculations. Turbulence was modelled using an unsteady Reynolds-Averaged Navier Stokes (URANS) model. In comparison to conventional combustion models, this approach allows for detailed investigations of the complex ignition process of the dual fuel combustion process. The unexpected inversely proportional relationship between start of injection (SOI) and start of combustion (SOC), a later start of injection makes for an earlier combustion of the main load, is only one of these interesting combustion phenomena, which can now be analyzed in detail. Further investigations are done for different engine load points and multiple pilot injection strategies. The simulation results are confirmed by experimental measurements at a medium speed dual fuel single cylinder research engine.

scholarly journals A Three-Zone Heat-Release Rate Model for Dual-Fuel Combustion

2010 ◽  
Vol 224 (11) ◽  
pp. 2423-2434 ◽  
Author(s):  
J Stewart ◽  
A Clarke
Keyword(s):  
Heat Release ◽  
Reaction Zone ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Gaseous Fuel ◽  
Dual Fuel ◽  
Pilot Fuel ◽  
Dual Fuel Combustion

Dual-fuel engines are modified compression ignition engines, where the primary source of fuel is a gaseous fuel, and ignition is provided by a ‘pilot’ injection of a reduced quantity of diesel. The generally accepted understanding of the dual-fuel engine describes its combustion process as proceeding in three stages. Initially, around half of the pilot will burn and entrain some gaseous fuel into an overall fuel-rich process. Subsequently, the remaining pilot fuel burns and entrains an increasing amount of the primary fuel into its reaction zone. In the final stage, a flame propagation process engulfs the remaining gaseous fuel. In this article, a three-zone model for the analysis of heat-release rate during the dual-fuel combustion process will be derived. This model will be tested against data obtained for diesel combustion and then applied to experimental data from a dual-fuel test program. It will be shown that there is little evidence to support the generally accepted description of the dual-fuel combustion process in a direct injection engine. The conclusion of this work is that dual-fuel combustion may be better considered as a diesel combustion process, where the gaseous fuel modifies the reaction zone surrounding each igniting droplet of the pilot fuel.

scholarly journals Analysis of Ignition Behavior in a Turbocharged Direct Injection Dual Fuel Engine Using Propane and Methane as Primary Fuels

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
A. C. Polk ◽  
C. M. Gibson ◽  
N. T. Shoemaker ◽  
K. K. Srinivasan ◽  
S. R. Krishnan
Keyword(s):  
Ignition Delay ◽  
Direct Injection ◽  
Critical Role ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Operating Conditions ◽  
Dual Fuel ◽  
Brake Mean Effective Pressure ◽  
Auto Ignition ◽  
Dual Fuel Combustion

Dual fuel engine combustion utilizes a high-cetane fuel to initiate combustion of a low-cetane fuel. The performance and emissions benefits (low NOx and soot emissions) of dual fuel combustion are well-known. Ignition delay (ID) of the injected high-cetane fuel plays a critical role in quality of the dual fuel combustion process. This paper presents experimental analyses of the ID behavior for diesel-ignited propane and diesel-ignited methane dual fuel combustion. Two sets of experiments were performed at a constant engine speed (1800 rev/min) using a four-cylinder direct injection diesel engine with the stock electronic conversion unit (ECU) and a wastegated turbocharger. First, the effects of fuel–air equivalence ratios (Фpilot ∼ 0.2–0.6 and Фoverall ∼ 0.2–0.9) on IDs were quantified. Second, the effects of gaseous fuel percent energy substitution (PES) and brake mean effective pressure (BMEP) (from 2.5 to 10 bars) on IDs were investigated. With constant Фpilot (>0.5), increasing Фoverall with propane initially decreased ID but eventually led to premature propane auto-ignition; however, the corresponding effects with methane were relatively minor. Cyclic variations in the start of combustion (SOC) increased with increasing Фoverall (at constant Фpilot) more significantly for propane than for methane. With increasing PES at constant BMEP, the ID showed a nonlinear trend (initially increasing and later decreasing) at low BMEPs for propane but a linearly decreasing trend at high BMEPs. For methane, increasing PES only increased IDs at all BMEPs. At low BMEPs, increasing PES led to significantly higher cyclic SOC variations and SOC advancement for both propane and methane. Finally, the engine ignition delay (EID), defined as the separation between the start of injection (SOI) and the location of 50% of the cumulative heat release, was also shown to be a useful metric to understand the influence of ID on dual fuel combustion. Dual fuel ID is profoundly affected by the overall equivalence ratio, pilot fuel quantity, BMEP, and PES. At high equivalence ratios, IDs can be quite short, and beyond a certain limit, can lead to premature auto-igniton of the low-cetane fuel (especially for a reactive fuel like propane). Therefore, it is important to quantify dual fuel ID behavior over a range of engine operating conditions.

scholarly journals Experimental Investigation and Benchmark Study of Oxidation of Methane–Propane–n-Heptane Mixtures at Pressures up to 100 bar

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3410 ◽  
Author(s):  
Sebastian Schuh ◽  
Ajoy Kumar Ramalingam ◽  
Heiko Minwegen ◽  
Karl Alexander Heufer ◽  
Franz Winter
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Suitable Model ◽  
Simulation Tools ◽  
Oxidation Of Methane ◽  
Ignition Delay Times ◽  
Development Costs ◽  
Dual Fuel Combustion

Dual fuel combustion exhibits a high degree of complexity due to the presence of different fuels like diesel and natural gas in initially different physical states and a spatially strongly varying mixing ratio. Optimizing this combustion process on an engine test bench is costly and time consuming. Cost reduction can be achieved by utilizing simulation tools. Although these tools cannot replace the application of test benches completely, the total development costs can be reduced by an educated combination of simulations and experiments. A suitable model for describing the reactions taking place in the combustion chamber is required to correctly reproduce the dual fuel combustion process. This is why in the presented study, four different reaction mechanisms are benchmarked to shock tube (ST) and rapid compression machine (RCM) measurements of ignition delay times (IDTs) at pressures between 60 and 100 bar and temperatures between 671 and 1284 K. To accommodate dual fuel relevant diesel-natural gas mixtures, methane–propane–n-heptane mixtures are considered as the surrogate. Additionally, the mechanisms AramcoMech 1.3, 2.0 and 3.0 are tested for methane–propane mixtures. The influence of pressure and propane/n-heptane content on the IDT based on the measurements is presented and the extent to which the mechanisms can reflect the IDT-changes discussed.

scholarly journals Laser-Induced Fluorescence Measurements of Formaldehyde and OH Radicals in Dual-Fuel Combustion Process in Engine

2015 ◽  
Vol 31 (12) ◽  
pp. 2269-2277 ◽  
Author(s):  
Qing-Long. TANG ◽  
◽  
Chao. GENG ◽  
Ming-Kun. LI ◽  
Hai-Feng. LIU ◽  
...  
Keyword(s):  
Combustion Process ◽  
Laser Induced Fluorescence ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Oh Radicals ◽  
Fluorescence Measurements ◽  
Dual Fuel Combustion
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