The NOx and N2O Emission Characteristics of an HCCI Engine Operated With N-Heptane

2007 ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range ◽  
Combustion Phase

This paper presents the NOx and N2O emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in Homogeneous Charge Compression Ignition (HCCI) combustion mode using an air-assist port fuel injector. The single-cylinder engine was fuelled with n-heptane for these experiments. The parameters examined include intake air temperature and pressure, air/fuel ratio, compression ratio, and exhaust gas recirculation (EGR) rate. The parameters were varied in order to change the combustion phasing from advanced (knocking) to retarded (incomplete combustion) conditions. NOx emissions were less than 5 ppm for a fairly wide range of combustion phases, except when knocking or incomplete combustion occurred, and were largely unaffected by the parameter varied when the combustion phase was within the acceptable range. It was also found that NOx emissions increased significantly when retarded and incomplete combustion was observed even though lower combustion temperatures were expected. The increased N2O and unburned hydrocarbon (THC) emissions usually observed with retarded combustion phasing, as well as the deteriorated combustion efficiency, may contribute to this unexpected increase in NOx emissions. It was also shown that N2O emissions were extremely low (less than 0.5 ppm) except when incomplete combustion was observed.

scholarly journals The NOx and N2O Emission Characteristics of an HCCI Engine Operated With n-Heptane

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Hailin Li ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Wally Chippior
Keyword(s):  
N2o Emission ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Incomplete Combustion ◽  
Hcci Combustion ◽  
Wide Range

This paper presents the oxides of nitrogen (NOx) and nitrous oxide (N2O) emission characteristics of a Cooperative Fuel Research (CFR) engine modified to operate in homogeneous charge compression ignition (HCCI) combustion mode. N-heptane was used as the fuel in this research. Several parameters were varied, including intake air temperature and pressure, air/fuel ratio (AFR), compression ratio (CR), and exhaust gas recirculation (EGR) rate, to alter the HCCI combustion phasing from an overly advanced condition where knocking occurred to an overly retarded condition where incomplete combustion occurred with excessive emissions of unburned hydrocarbons (UHC) and carbon monoxide (CO). NOx emissions below 5 ppm were obtained over a fairly wide range of operating conditions, except when knocking or incomplete combustion occurred. The NOx emissions were relatively constant when the combustion phasing was within the acceptable range. NOx emissions increased substantially when the HCCI combustion phasing was retarded beyond the optimal phasing even though lower combustion temperatures were expected. The increased N2O and UHC emissions observed with retarded combustion phasing may contribute to this unexpected increase in NOx emissions. N2O emissions were generally less than 0.5 ppm; however, they increased substantially with excessively retarded and incomplete combustion. The highest measured N2O emissions were 1.7 ppm, which occurred when the combustion efficiency was approximately 70%.

NO and N2O Formation/Decomposition Characteristics During Co-Combustion of Coal With Biomass

2005 ◽  
Author(s):  
Asri Gani ◽  
Ichiro Naruse
Keyword(s):  
Coal Combustion ◽  
Co2 Emission ◽  
N2o Emission ◽  
Reaction Scheme ◽  
Volatile Matter ◽  
N2o Emissions ◽  
Emission Characteristics ◽  
Homogeneous Reaction ◽  
Fuel Cost ◽  
N2o Formation

Co-combustion technologies of coal with biomass have been applied in many practical coal combustion boilers in order to reduce CO2 emission, fuel cost and so forth. Furthermore, the biomass may be able to enhance the combustion performance and to control NOx and N2O emissions since the biomass contains high volatile matter and evolves NH3 as the main volatile N-species. This study focuses on NOx and N2O emission characteristics during co-combustion of coal with biomass. The main results obtained show that emission amount of NO and N2O during co-combustion is relatively more than that during coal combustion. At least, NO behavior can be simulated by the homogeneous reaction scheme relating to NOx even at constant temperature. However, the N2O behavior will be influenced by heterogeneous schemes due to char particles during co-combustion.

Unsteady Simulations of a Low NOx LDI Combustor for Environmentally Responsible Aviation Engines

2015 ◽  
Author(s):  
Scott A. Drennan ◽  
Gaurav Kumar ◽  
Erlendur Steinthorsson ◽  
Adel Mansour
Keyword(s):  
Experimental Data ◽  
Complex Geometry ◽  
Mesh Refinement ◽  
Operating Conditions ◽  
Design Parameters ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Cfd Simulations ◽  
Wide Range ◽  
Environmentally Responsible

A key objective of NASA’s Environmentally Responsible Aviation (ERA) research program is to develop advanced technologies that enable 75% reduction of LTO NOx emissions of N+2 aviation gas turbine engines relative to the CAEP 6 standard. To meet this objective, a new advanced multi-point fuel injector was proposed and tested under the NASA ERA program. The new injector, called the three-zone injector, or 3ZI, uses fifteen spray cups arranged in three zones. Swirling air flows into each cup and fuel is introduced via pressure swirl atomizers within the cup. Multiple design parameters impact the performance of the injector, such as the location of the atomizer within the spray cup, the spray angle and cup-to-cup spacing. To fully understand the benefits and trade-offs of various injector design parameters and to optimize the performance of the injector, detailed CFD simulations are an essential tool. Furthermore, the CFD methodology must allow easy changes in design parameters and guarantee consistent and comparable accuracy from one design iteration to the next. This paper investigates the use of LES in reacting and non-reacting flows and compares against the NOx experimental data for the multi-point atomization strategy of the injector. The CFD simulations employ an automatically generated Cartesian cut-cell meshing approach with mesh refinement applied near complex geometry and spray regions. Adaptive Mesh Refinement (AMR) is used to refine mesh in regions of high gradients in velocity and temperature. The CFD simulations use boundary and operating conditions based on experimental data for air flow and spray atomization obtained from LDV and PDPA characterizations of the spray respectively. The results are extended to reacting flow using a detailed reaction mechanism and predictions of NOx emissions are compared to experimental data. Overall NOx predictions were consistently less than experimental values. However, the NOx prediction trends showed excellent agreement with experimental data across the wide range of equivalence ratios investigated.

Development of a Small-Scale Catalytic Gas Turbine Combustor

1982 ◽  
Vol 104 (1) ◽  
pp. 52-57 ◽  
Author(s):  
S. J. Anderson ◽  
M. A. Friedman ◽  
W. V. Krill ◽  
J. P. Kesselring
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Efficiency ◽  
Small Scale ◽  
Time Interval ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Opposed Jet

Catalytically supported thermal combustion can provide low NOx emissions with gaseous and distillate fuels while maintaining high combustion efficiency. For stationary gas turbines, catalytic combustion may be the only emerging technology that can cost effectively meet recent federal regulations for NOx emissions. Under EPA sponsorship, a small-scale, catalytic gas turbine combustor was developed to evaluate transient and steady state combustor performance. The combustor consisted of a multiple air-atomizing fuel injector, an opposed jet igniter, and a graded-cell monolithic reactor. System startup, including opposed jet ignition and catalyst stabilization, was achieved in 250 seconds. This time interval is comparable to conventional gas turbines. Steady state operation was performed at 0.505 MPa (5 atmospheres) pressure and 15.3 m/s (50 ft/s) reference velocities. Thermal NOx emissions were measured below 10 ppmv, while fuel NOx conversion ranged from 75 to 95 percent. At catalyst bed temperatures greater than 1422K (2100°F), total CO and UHC emissions were less than 50 ppmv indicating combustion efficiency greater than 99.9 percent. Compared with conventional gas turbine combustors, the catalytic reactor operates only within a relatively narrow range of fuel/air ratios. As a result, modified combustor air distribution or fuel staging will be required to achieve the wide turndown required in large stationary systems.

Experimental and Simulation Study of Fuel Injection Timing, Pressure and EGR for Lower Exhaust Emissions From Diesel HCCI Combustion

2009 ◽  
Author(s):  
S. Juttu ◽  
S. S. Thipse ◽  
N. V. Marathe ◽  
M. K. Gajendra Babu
Keyword(s):  
Simulation Study ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Emissions ◽  
Injection Timing ◽  
Nox Emissions ◽  
Hcci Combustion ◽  
Fuel Injection Timing ◽  
Start Of Injection ◽  
Wide Range

The objective of this work is to study the effect of different control parameters viz. EGR, fuel injection pressure and start of injection timing on exhaust emissions from diesel fueled HCCI combustion concept. A 4-cylinder LCV engine has been selected for experiments and FIRE 3D CFD software was used for simulation study. The basic idea of the simulation study is to find the suitable EGR ratio to run the engine on HCCI combustion mode so as to avoid any damage to the engine during testing. From simulation study, it was observed that the minimum EGR required for running the engine at 5.6 bar BMEP @ 2500 rpm in HCCI mode is approximately 45%. The trends of simulation results viz. soot and NOx emissions are closely following the experiments. The experiments were conducted at different loads at 2500 rpm and EGR varied from 0% to 60%. With increased EGR ratio, soot bump was observed at 50%, 75% and 100%. The BTE dropped to 24.5% from 33.5%. The effect of fuel injection pressures (750bar, 1000bar and 1500bar) were studied to improve the BTE and to control soot bump over a wide range injection timings EGR ratio. Detailed experiments were conducted at 2.8 bar BMEP @ 2500 rpm to study simultaneous reduction of NOx, SOOT, UHC and CO emissions from diesel HCCI combustion. At injection pressure (1500 bar), advanced fuel injection timing and high EGR ratio, the soot CO and THC emissions were reduced significantly without penalty on NOx emissions. The BTE was improved from 24.5% to 31% against 33.5% of convention diesel combustion.

Small Industrial Gas Turbine Combustor Performance With Low BTU Gas Fuels

1985 ◽  
Author(s):  
D. W. Bahr ◽  
P. E. Sabla ◽  
J. W. Vinson
Keyword(s):  
Combustion Efficiency ◽  
Industrial Applications ◽  
Industrial Processes ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Flow Rates ◽  
Fuel Injectors ◽  
Wide Range ◽  
Exit Temperature ◽  
Industrial Gas Turbine

To permit the use of gasifier-generated low BTU gas fuels in the LM500 engine, a modified version of its existing combustor was defined and tested. The LM500 engine is a small aircraft-derivative engine in the four megawatt class and is used in a variety of industrial applications. The combustor of this engine consists of a short-length and compact annular design with 18 fuel injectors. To accommodate the high volumetric flow rates associated with the use of low BTU gas fuels, a modified fuel injector configuration was defined. With this modified configuration, the combustor was found to operate satisfactorily with low BTU gases over a wide range of heating values. Stable combustion was obtained with fuels having heating values as low as 3.72 MJ/m3 (100 BTU/SCF). Also, acceptable combustion efficiency levels and exit temperature distributions were obtained. Based on these results, it is concluded that the LM500 engine can satisfactorily accommodate low BTU gas fuels typical of those produced by coal or biomass gasifiers and by other industrial processes.

Experimental Evaluation of a Low NOx LBG Combustor Using Bypass Air

1990 ◽  
Author(s):  
T. Nakata ◽  
M. Sato ◽  
T. Ninomiya ◽  
T. Abe ◽  
S. Mandai ◽  
...  
Keyword(s):  
Combustion Zone ◽  
Calorific Value ◽  
Combustion Efficiency ◽  
Nox Emissions ◽  
Bypass Valve ◽  
Wide Range ◽  
Ammonia Conversion ◽  
Lower Load ◽  
Low Nox Combustion ◽  
Combustion Tests

A 150-MW, 1300°C (1573 K) class gas turbine combustor firing coal-gasified fuel has been designed. Main purpose of the present paper is first to estimate CO and NOx emissions, and second to discuss the low NOx combusion technology burning such a low-BTU gas. The full-scale, atmospheric-pressure combustion tests were conducted over a wide range of conditions using bypass air. The results are summarized as follows: (1) A designed combustor has an excellent combustion efficiency of 99.6 percent even when the calorific value of fuel drops to 650 kcal/m3N. (2) CO and NOx emissions can be estimated by the air ratio in primary combustion zone. (3) The role of air bypass valve is important for low NOx combustion, and to give stable combustion at lower load conditions. (4) Ammonia conversion to NOx is minimized with a optimum air ratio in primary combustion zone.

Single-Cylinder Testing of a High-Pressure Electronic Pilot Fuel Injector for Low NOx Emission Dual Fuel Engines: Part II—Optimization, Startability, and Inflammability Testing

1990 ◽  
Vol 112 (3) ◽  
pp. 422-430 ◽  
Author(s):  
J. Workman ◽  
G. M. Beshouri
Keyword(s):  
Fuel Consumption ◽  
Fuel Injection ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Single Cylinder ◽  
Percent Improvement ◽  
Wide Range ◽  
Pilot Fuel ◽  
Dual Fuel Engines ◽  
Low Nox Emission

Single-cylinder testing of an Electronic Pilot Fuel Injection (EPFI) system (reported in Part I) indicated that a 45 percent reduction in NOx emissions could be obtained with a 3 percent improvement in fuel consumption by replacing the mechanical system, delivering 6 percent pilot, with the EPFI at 2.9 percent delivery. Further optimization testing of this system at pilot levels down to 0.7 percent over a wide range of timings and air/fuel ratios resulted in even further reductions in NOx emissions without fuel penalty. The EPFI system can yield NOx emissions levels significantly below 2 g/BHP-h with an improvment in fuel consumption of at least 3–4 percent, and probably yield emissions level as low as 0.5 g/BHP-h without substantial penalties in efficiency or operability.

scholarly journals Conical Grid Plate Flame Stabilizers for Combustor Primary Zones

1985 ◽  
Author(s):  
A. F. Ali ◽  
G. E. Andrews
Keyword(s):  
Residence Time ◽  
Fuel Injection ◽  
Combustion Efficiency ◽  
Shear Layers ◽  
Injection System ◽  
Fuel Injection System ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Primary Zone ◽  
Grid Plate

Emission results are presented for a jet shear layer flame stabiliser design consisting of a 90° conical flame stabiliser with an array of holes and a central annular vaporiser fuel injection system. This design was tested with premixed propane and air and with direct propane injection into the vaporiser at two blockages and approach velocities. The results showed that an array of jet shear layers could be fuelled by a single fuel injector without incurring excessive NOx emissions. An increase in the primary zone residence time was found to result in an improved combustion efficiency, with no increase in NOx, provided that the stabiliser blockage was increased to maintain the pressure loss.

Study of Pulse Spray, Heat Release, Emissions and Efficiencies in a Compound Diesel HCCI Combustion Engine

2004 ◽  
Author(s):  
Wanhua Su ◽  
Xiaoyu Zhang ◽  
Tiejian Lin ◽  
Yiqiang Pei ◽  
Hua Zhao
Keyword(s):  
Heat Release ◽  
Combustion Engine ◽  
Combustion Efficiency ◽  
Diffusion Combustion ◽  
Injection Timing ◽  
Nox Emissions ◽  
Injection Process ◽  
Hcci Combustion ◽  
Air Mixing ◽  
Combustion Technology

A compound diesel HCCI combustion technology has been developed based on the combustion strategies of combination of controlled premixed charge compression ignition (CPCCI) through multi-injections and lean diffusion combustion (LDC) organized by a mixing enhanced combustion chamber. The purpose of this paper is to investigate the fuel spray evolution during multi-injections, heat release mode, thermo-efficiency and exhaust emissions from the compound combustion. In this work, the STAR-CD based, multidimensional modeling is employed to improve the understanding and assist the optimization of the multiple injection process. The parameters explored include the effects of injection timing, dwell time, and the pulse width. Insight generated from these studies provides guidelines on designing an injection profile for optimization of fuel-air mixing. By comparison of different heat release modes of conventional diesel combustion, the pure HCCI combustion and the compound HCCI combustion, the engine heat release can be summarized as forward concentrated mode (FC mode), post concentrated mode (PC mode) and dispersed mode (DS mode). The FC mode gives the highest thermo-efficiency but with highest NOx emissions. The PC mode gets lower NOx emissions but with the drawback of lower thermo-efficiency and higher soot emissions. The DS mode is a flexible heat release mode created by the compound HCCI combustion. A typical DS mode reveals two equivalent peaks of heat release. The first peak represents the CPCCI combustion and the later peak represents the lean diffusion combustion. The thermo-efficiency in a DS mode can reach approximately as high as that in FC mode, while NOx and soot emission can be reduced simultaneously and remarkably. The combustion efficiency and the heat loss in different combustion mode are also discussed.

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