Effects of Ambient Air Humidity on Emissions and Efficiency of Large-Bore Lean-Burn Otto Gas Engines in Development and Application

2020 ◽  
Author(s):  
Tomas Bartkowski ◽  
Stefan Eicheldinger ◽  
Maximilian Prager ◽  
Georg Wachtmeister
Keyword(s):  
Air Conditioning ◽  
Test Bench ◽  
Water Injection ◽  
Measurement Data ◽  
Ambient Air ◽  
Injection System ◽  
Nox Emissions ◽  
Air Humidity ◽  
Ambient Conditions ◽  
Lean Burn

Abstract The use of large-bore Otto gas engines is currently spreading widely considering the growing share of Power-To-Gas (P2G) solutions using renewable energies. P2G with a Combined Heat and Power (CHP) plant offers a promising way of utilizing chemical energy storage to provide buffering for volatile energy sources such as wind and solar power all over the world. Therefore, ambient conditions like air temperature, humidity and pressure can differ greatly between the location and time of engine operation, influencing its performance. Especially lean-burn Otto processes are sensitive to changes in ambient conditions. Besides, targeted use of humidity variation (e.g. through water injection in the charge air or combustion chamber) can help to reduce NOx emissions at the cost of a slightly lower efficiency in gas engines, being an alternative to selective catalytic reduction (SCR) exhaust gas aftertreatment. The ambient air condition boundaries have to be considered already in the early stages of combustion development, as they can also have a significant effect on generated measurement data in combustion research. To investigate the behavior, a test bench with a natural gas (CNG) powered single-cylinder research engine (piston displacement 4.77 1) at the Institute of Internal Combustion Engines (LVK) of the Technical University of Munich (TUM) was equipped with a sophisticated charge air conditioning system. This includes an air compressor and refrigeration dryer, followed by temperature and pressure control, as well as a controlled injection system for saturated steam and homogenizing containers, enabling the test bench to precisely emulate a widespread area of charge air parameters in terms of pressure, temperature and humidity. With this setup, different engine tests were conducted, monitoring and evaluating the engine’s emission and efficiency behavior regarding charge air humidity. In a first approach, the engine was operated maintaining a steady air-fuel equivalence ratio λ, fuel energy input (Q̇fuel = const.) and center of combustion (MFB 50%) while the relative ambient humidity was varied in steps between 21% and 97% (at 22 °C and 1013.25 hPa). Results show a significant decrease in nitrogen oxides (NOx) emissions (−39.5%) and a slight decrease in indicated efficiency (−1,9%) while hydrocarbon (THC) emissions increased by around 60%. The generated data shows the high significance of considering charge air conditioning already in the development stage at the engine test bench. The comparability of measurement data depends greatly on ambient air humidity. In a second approach, the engine was operated at a constant load and constant NOx emissions, while again varying the charge air humidity. This situation rather reflects an actual engine behavior at a CHP plant, where today often NOx–driven engine control is used, maintaining constant NOx emissions. The decrease in indicated efficiency was comparable to the prior measurements, while the THC emissions showed only a mild increase (5%). From the generated data it is, for instance, possible to derive operational strategies to compensate for changes in ambient conditions while maintaining emission regulations as well as high-efficiency output. Furthermore, the results suggest possibilities, but also challenges of utilizing artificial humidification (e.g. through water injection) considering the effects on THC emissions and efficiency. A possible shift of the knocking limit to earlier centers of combustion with higher humidity is to be investigated. The main goal is the further decrease of NOx emissions, increase of efficiency, while still maintaining hydrocarbon emissions.

The Control of NOx and CO Emissions From 7-MW Gas Turbines With Water Injection as Influenced by Ambient Conditions

1985 ◽  
Author(s):  
W. S. Y. Hung ◽  
D. D. Agan
Keyword(s):  
Ambient Temperature ◽  
Gas Turbines ◽  
Water Injection ◽  
Field Measurements ◽  
Field Testing ◽  
Ambient Air ◽  
Injection System ◽  
Ambient Conditions ◽  
Water Control ◽  
Fuel Gas

Interpretation of federal emissions regulations by a local regulatory agency resulted in the requirement to develop a special water control system for stationary gas turbines to meet stringent NOx and CO emissions limits. Extensive field testing of two 7-MW industrial gas turbines burning natural gas was performed to establish the effects of ambient air temperature, humidity and water injection on NOx and CO emissions. The predictions from a proven NOx model were shown to be within the uncertainty of the field measurements and were used to determine the water flow rates required when burning No. 2 distillate oil. Over the ambient temperature range considered, the analytical model predicted a linear increase in NOx emissions as ambient temperature increases. This was supported by the data gathered and the thermal NOx rate equation. Subsequently, a water injection system was successfully developed to control NOx and CO emissions from the 7-MW dual fuel gas turbine as a function of ambient temperature and turbine load.

A NOx Reduction Project for a GT11 Type Gas Turbine

2005 ◽  
Author(s):  
Lars O. Nord ◽  
David R. Schoemaker ◽  
Helmer G. Andersen
Keyword(s):  
Power Plant ◽  
Distribution System ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Measurement Data ◽  
Combustion Stability ◽  
Study Phase ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Exhaust Temperature

A study was initiated to investigate the possibility of significantly reducing the NOx emissions at a power plant utilizing, among other manufacturers, ALSTOM GT11 type gas turbines. This study is limited to one of the GT11 type gas turbines on the site. After the initial study phase, the project moved on to a mechanical implementation stage, followed by thorough testing and tuning. The NOx emissions were to be reduced at all ambient conditions, but particularly at cold conditions (below 0°C) where a NOx reduction of more than 70% was the goal. The geographical location of the power plant means cold ambient conditions for a large part of the year. The mechanical modifications included the addition of Helmholtz damper capacity with an approximately 30% increase in volume for passive thermo-acoustic instability control, significant piping changes to the fuel distribution system in order to change the burner configuration, and installation of manual valves for throttling of the fuel gas to individual burners. Subsequent to the mechanical modifications, significant time was spent on testing and tuning of the unit to achieve the wanted NOx emissions throughout a major part of the load range. The tuning was, in addition to the main focus of the NOx reduction, also focused on exhaust temperature spread, combustion stability, CO emissions, as well as other parameters. The measurement data was acquired through a combination of existing unit instrumentation and specific instrumentation added to aid in the tuning effort. The existing instrumentation readings were polled from the control system. The majority of the added instrumentation was acquired via the FieldPoint system from National Instruments. The ALSTOM AMODIS plant-monitoring system was used for acquisition and analysis of all the data from the various sources. The project was, in the end, a success with low NOx emissions at part load and full load. As a final stage of the project, the CO emissions were also optimized resulting in a nice compromise between the important parameters monitored, namely NOx emissions, CO emissions, combustion stability, and exhaust temperature distribution.

Ambient Condition Effects on NOx and CO Emissions From Process Heaters

2008 ◽  
Author(s):  
Wesley R. Bussman ◽  
Charles E. Baukal
Keyword(s):  
Atmospheric Pressure ◽  
Ambient Air ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
Natural Draft ◽  
Actual Operating ◽  
Wide Range ◽  
Pollution Emissions

Because process heaters are typically located outside, their operation is subject to the weather. Heaters are typically tuned at a given set of conditions; however, the actual operating conditions may vary dramatically from season to season and sometimes even within a given day. Wind, ambient air temperature, ambient air humidity, and atmospheric pressure can all significantly impact the O2 level, which impacts both the thermal efficiency and the pollution emissions from a process heater. Unfortunately, most natural draft process burners are manually controlled on an infrequent basis. This paper shows how changing ambient conditions can considerably impact both CO and NOx emissions if proper adjustments are not made as the ambient conditions change. Data will be presented for a wide range of operating conditions to show how much the CO and NOx emissions can be affected by changes in the ambient conditions for fuel gas fired natural draft process heaters, which are the most common type used in the hydrocarbon and petrochemical industries. Some type of automated burner control, which is virtually non-existent today in this application, is recommended to adjust for the variations in ambient conditions.

Adiabatic Effectiveness and Flow Field Measurements in a Realistic Effusion Cooled Lean Burn Combustor

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Antonio Andreini ◽  
Riccardo Becchi ◽  
Bruno Facchini ◽  
Lorenzo Mazzei ◽  
Alessio Picchi ◽  
...  
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Injection System ◽  
Wall Region ◽  
Test Model ◽  
Nox Emissions ◽  
Lean Burn ◽  
Experimental Apparatus ◽  
Adiabatic Effectiveness ◽  
The Impact

Over the last ten years, there have been significant technological advances toward the reduction of NOx emissions from civil aircraft engines, strongly aimed at meeting stricter and stricter legislation requirements. Nowadays, the most prominent way to meet the target of reducing NOx emissions in modern combustors is represented by lean burn swirl stabilized technology. The high amount of air admitted through a lean burn injection system is characterized by very complex flow structures such as recirculations, vortex breakdown, and precessing vortex core (PVC) that may deeply interact in the near wall region of the combustor liner. This interaction makes challenging the estimation of film cooling distribution, commonly generated by slot and effusion systems. The main purpose of the present work is the characterization of the flow field and the adiabatic effectiveness due to the interaction of swirling flow, generated by real geometry injectors, and a liner cooling scheme made up of a slot injection and an effusion array. The experimental apparatus has been developed within EU project LEMCOTEC (low emissions core-engine technologies) and consists of a nonreactive three-sectors planar rig; the test model is characterized by a complete cooling system and three swirlers, replicating the geometry of a GE Avio PERM (partially evaporated and rapid mixing) injector technology. Flow field measurements have been performed by means of a standard 2D PIV (particle image velocimetry) technique, while adiabatic effectiveness maps have been obtained using PSP (pressure sensitive paint) technique. PIV results show the effect of coolant injection in the corner vortex region, while the PSP measurements highlight the impact of swirled flow on the liner film protection separating the contribution of slot and effusion flows. Furthermore, an additional analysis, exploiting experimental results in terms of heat transfer coefficient, has been performed to estimate the net heat flux reduction (NHFR) on the cooled test plate.

Researching Air-Conditioning Addiction and Ways of Puncturing Practice: Professional Office Workers and the Decision to Go outside

2011 ◽  
Vol 43 (12) ◽  
pp. 2838-2856 ◽  
Author(s):  
Russell Hitchings
Keyword(s):  
Social Practice ◽  
Air Conditioning ◽  
Ambient Air ◽  
Office Workers ◽  
Ambient Conditions ◽  
The Everyday ◽  
The World ◽  
Working Day

Though many people around the world now spend much of their time surrounded by bodies of controlled ambient air indoors, we still know relatively little about the subjectivities involved. Some have deployed the idea of air-conditioning addiction. Others emphasise the enjoyable sensations associated with temporary escape. The research described in this paper sought to add some empirical depth to these discussions by combining theories of social practice with a programme of serial interviews to examine how a sample of city professionals felt about the long periods they spent inside air-conditioned offices. The rationale was that, through these means, it should be possible to identify ways of disrupting otherwise habitual indoor existences and thereby discourage people from becoming increasingly reliant upon ambient conditions that are environmentally costly to supply. Describing their passage through a typical working day, this paper focuses on the moments when it might have occurred to them to spend time outside and how certain mental and material elements combined to impede the arrival of this decision. This exercise is used to draw out suggestions about how a better relationship between professional office workers and the everyday outdoors could be encouraged. The broader conclusion is that contextual studies which examine how places and practices produce decisions, instead of assuming individual people merely make them, have their part to play in fostering positive social futures.

Optimal Operational Planning of Cogeneration Systems With Microturbine and Desiccant Air-Conditioning Units

2004 ◽  
Author(s):  
Satoshi Gamou ◽  
Koichi Ito ◽  
Ryohei Yokoyama
Keyword(s):  
Energy Flow ◽  
Energy Demand ◽  
Air Conditioning ◽  
Optimization Problem ◽  
Energy Charge ◽  
Ambient Air ◽  
Operational Planning ◽  
Optimization Approach ◽  
Analysis Method ◽  
Air Humidity

Economic and energy-saving characteristics of cogeneration systems with microturbine and desiccant air-conditioning units are investigated on system operational planning. An optimization approach is adopted to rationally evaluate these characteristics. In this approach, on/off and rated/part load status of operation of equipment and energy flow rates are determined so as to minimize the hourly energy charge subject to satisfaction of energy demand requirements. In this optimization problem, performance characteristics of the microturbine and desiccant air-conditioning units are modeled in consideration of the influence due to ambient air temperature. Moreover, the influence due to ambient air humidity is also considered in the desiccant air-conditioning unit using the psychrometric diagram. The implementation of the numerical analysis method, discussed in this paper, to two cogeneration systems, clearly shows economic and operational benefits of using desiccant air-conditioning.

Optimal Operational Planning of Cogeneration Systems With Microturbine and Desiccant Air Conditioning Units

2005 ◽  
Vol 127 (3) ◽  
pp. 606-614 ◽  
Author(s):  
Satoshi Gamou ◽  
Koichi Ito ◽  
Ryohei Yokoyama
Keyword(s):  
Energy Flow ◽  
Energy Demand ◽  
Air Conditioning ◽  
Optimization Problem ◽  
Energy Charge ◽  
Ambient Air ◽  
Operational Planning ◽  
Optimization Approach ◽  
Analysis Method ◽  
Air Humidity

Economic and energy-saving characteristics of cogeneration systems with microturbine and desiccant air-conditioning units are investigated on system operational planning. An optimization approach is adopted to rationally evaluate these characteristics. In this approach, on/off and rated/part load status of operation of equipment and energy flow rates are determined so as to minimize the hourly energy charge subject to satisfaction of energy demand requirements. In this optimization problem, performance characteristics of the microturbine and desiccant air-conditioning units are modeled in consideration of the influence due to ambient air temperature. Moreover, the influence due to ambient air humidity is also considered in the desiccant air-conditioning unit using the psychrometric diagram. The implementation of the numerical analysis method, discussed in this paper, to two cogeneration systems, clearly shows economic and operational benefits of using desiccant air-conditioning.

Investigations on Winter Tire Characteristics on Different Track Surfaces Using a Statistical Approach

2015 ◽  
Vol 43 (3) ◽  
pp. 195-215 ◽  
Author(s):  
Bernd Wassertheurer ◽  
Frank Gauterin
Keyword(s):  
Test Bench ◽  
Measurement Data ◽  
Simulation Models ◽  
Operating Conditions ◽  
Ambient Conditions ◽  
Fitting Procedures ◽  
Institute Of Technology ◽  
Technology Institute ◽  
Main Effects ◽  
Tire Models

ABSTRACT The availability of reliable tire simulation models is necessary for performing accurate vehicle-handling simulations. Parameterizing of tire models, such as the Magic Formula (MF) tire model, means extensive measurement and complex fitting procedures. In addition, a general problem is that parameterized MF models are not simply adaptable to other track surfaces (e.g., dry, wet, or snowy tracks), which is a problem, especially for winter tire modeling. To face this drawback, a research project in cooperation between BMW and the Karlsruhe Institute of Technology, Institute of Vehicle System Technology, has been initiated. The institute's internal drum test bench provides the opportunity to perform measurements on different track surfaces and various operating conditions. To identify main effects on tire performance and tire characteristics, comprehensive measurements on snow, ice, wet asphalt, and dry Safety-Walk surfaces have been carried out using three different winter tires. Experimental designs have been worked out using the method of design of experiments (DoE) to reduce the number of measurements and to decrease measuring expenditure, especially on snow track surfaces. By using DoE, all statistic effects can be analyzed despite reducing the number of measurements. Measurement data have been analyzed using extensive statistical methods. Thereby, effects on the tire characteristics have been empirically identified, and general predications will be presented in the article. We show identified main effects of track and ambient conditions on tire performance and tire characteristics. Furthermore, this article demonstrates the approach of using DoE to perform lean measurements as well as illustrates the realization of executing the measurements on different track surfaces on the test bench. These results will also be a starting basis for establishing a novel empirical model for adopting tire characteristic curves and MF tire models on alternative road and ambient conditions.

Urea-SCR system development in the mitigation of NOx emissions from diesel engines – A review study

2020 ◽  
Vol 09 ◽  
Author(s):  
Mina Mehregan
Keyword(s):  
Nitrogen Oxides ◽  
Diesel Engines ◽  
Energy Demand ◽  
Catalytic Reduction ◽  
Control Strategies ◽  
Ambient Air ◽  
Short Review ◽  
Injection System ◽  
Forest Damage ◽  
Nox Emissions

Introduction: Due to energy demand concerns, diesel engines have gained much attraction recently compared to petrol engines because of their higher thermal efficiencies. However, they emit larger amount of NOx emissions into the atmosphere. Nitrogen oxides are known as important ambient air pollutants which are responsible for health problems, forest damage and buildings corrosion. Therefore, using emissions control strategies for diesel engines are required in order to have a cleaner environment. Urea-SCR (selective catalytic reduction of NOx by urea) after-treatment system is considered as one of the most efficient techniques available to reduce engine-out NOx emissions sufficiently. Conclusion: This review article discusses a short review on all the methods suggested to diminish nitrogen oxides emissions and then presents a comprehensive survey on developing urea-SCR unit -whether from catalyst development aspect or from injection system modification point of view- in diesel engines to meet strict emissions regulations.

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