Equilibrium and Kinetics Analysis of NOx Reduction From Biogas Combustion

2011 ◽  
Author(s):  
Jorge Chavero ◽  
Duff Harrold ◽  
Timothy Marbach
Keyword(s):  
Nox Reduction ◽  
The United States ◽  
Operating Parameters ◽  
Nox Emissions ◽  
Potential Generation ◽  
Kinetics Analysis ◽  
Microwave System ◽  
Equilibrium And Kinetics ◽  
Generation Capacity ◽  
Biogas Engines

The undeveloped potential generation capacity of landfills, wastewater digesters and food digesters is estimated at 600 MW in California and 3,000 MW in the United States. California’s 2000 dairies have the potential to produce an estimated 40 million cubic feet of biogas per day, representing a potential generation capacity of about 140 MW. One of the most significant challenges facing the combustion of digester biogas is high NOx emissions. Sulfur in the biogas poisons post-combustion catalysts, rendering them ineffective for reducing NOx emissions. To address this challenge, an integrated pollution capture and microwave system has been developed to reduce NOx emissions from biogas engines. The feasibility of reburning the captured NOx was assessed and the effect of various operating parameters, including temperature, pressure, and reactant composition were determined using chemical equilibrium and kinetic modeling.

The Design and Operation of an Advanced NOx Control System on the New 636TPD MWC at the Lee County WTE Facility

2009 ◽  
Author(s):  
Alexander S. Dainoff ◽  
Dennis Anacker
Keyword(s):  
Nox Reduction ◽  
Reduction Process ◽  
The United States ◽  
Waste To Energy ◽  
Nox Emissions ◽  
Gas Temperature ◽  
Boiler Load ◽  
Energy Unit ◽  
Lee County ◽  
Ammonia Slip

In September of 2007, a new 636TPD Municipal Waste Combustor was brought on line at the Lee County WTE Facility in Fort Myers, FL operated by Covanta Energy. This unit was the first new Waste to Energy unit built in the United States in a number of years and included a lower permitted daily average NOx emissions requirement of 110ppm @ 7%O2 while maintaining ammonia slip to less than 10ppm. To meet this new stringent NOx emissions requirement, the boiler was designed with advanced combustion controls including Flue Gas Recirculation combined with a urea based Selective Non-Catalytic Reduction Process to provide a combined NOx reduction of approximately 70% while maintaining the required ammonia slip. The SNCR System provided by Fuel Tech was designed with 3 levels of seven wall injectors installed in the upper furnace. Both boiler load and Furnace Gas Temperature were used as a feed forward control with the CEM NOx signal as a feed back to automatically select the injector levels and reagent feed rates to maintain the targeted NOx while also maintaining ammonia slip control. This paper will outline the design considerations, the details of the process and the operation of the systems on this unit.

THE METHOD OF NITROGEN OXIDE EMISSION REDUCTION DURING THE COMBUSTION OF GASEOUS FUEL IN MUNICIPAL THERMAL POWER BOILERS

2020 ◽  
Vol 5 (3) ◽  
pp. 18-33
Author(s):  
Sylwia Janta-Lipińska ◽  
Keyword(s):  
European Union ◽  
Emission Reduction ◽  
Thermal Power ◽  
Nox Reduction ◽  
Gaseous Fuel ◽  
Nox Emissions ◽  
The European Union ◽  
Nitrogen Oxide Emission ◽  
Boiler Efficiency ◽  
Injection Technology

The nitrogen oxides in a flame of burning fuel can be created by many mechanisms. The amount of NOx concentration emitted to the ground atmosphere mainly depends on the type of fuel burned in the industrial and heating boilers. Changes in the country's thermal policy and requirements that are set for us by the European Union States are forcing us to reduce greenhouse gas emissions. Directed metered ballast method is one of the most attractive techniques for reducing NOx emissions. In recent years, moisture injection technology is still investigated on low and medium power thermal power boilers operating on gaseous fuel. The goal of this work was to perform the investigations of the process of a moisture injection into the zones of decisive influence (SDW-I and SDW-II) on steam and water boilers: DKVR 10-13, DKVR 20-13, DE 25-14 and PTVM-50. The obtained results clearly show how the proposed method affects NOx reduction and boiler efficiency.

NOx Emissions in a Steel Reheat Furnace Firing By-Product Fuels

2001 ◽  
Author(s):  
Bradley R. Adams ◽  
Dave H. Wang
Keyword(s):  
Low Cost ◽  
Nox Reduction ◽  
Coke Oven ◽  
Cfd Modeling ◽  
Stoichiometric Ratio ◽  
Nox Emissions ◽  
Confined Space ◽  
Nox Formation ◽  
Reheat Furnace ◽  
Bottom Zone

Abstract A DOE-funded program was used to understand the mechanisms that control the formation of NOx during the combustion of steelmaking by-product fuels and to investigate possible low-cost control options to minimize the NOx emissions. This paper discusses the CFD modeling results of NOx emissions in a reheat furnace. The reheat furnace has a total of 20 burners distributed over three firing zones. The furnace is fired at a rate of 250 × 106 Btu/hr and an overall stoichiometric ratio of 1.06 (fuel lean). Fuels with heating values of approximate 500 Btu/SCF were examined, including coke oven gas (COG), blast furnace gas (BFG) and a blend of COG, BFG, natural gas (NG) and nitrogen. A good range of process variables was modeled to examine effects of fuel type, air preheat, stoichiometric ratio, firing rate and burner stoichiometry distribution on NOx emissions. Modeling results indicated that NOx formation in the reheat furnace is dominated by thermal NO, with some variation depending on the fuel fired. Temperature profiles showed an effective separation of the furnace interior into top and bottom zones as a result of the steel slab barrier. Higher temperatures characterized the bottom zone and elevated NOx levels as a result of the confined space and enhanced fuel air mixing provided by the slab supports. Results also showed that reburning of NOx plays a significant role in final NOx emissions with 30–40% of NOx formed being reduced by reburning in most cases. Modeling identified that operating the side burners in each burner zone slightly substoichiometric (while maintaining the overall furnace stoichiometry at 1.06) provided significant NOx reduction via reburning. NOx reductions of 23% and 30% were predicted when firing with COG and COG-NG-Air fuels, respectively. Overall furnace exit temperatures and heat flux profiles were not significantly affected by the biased firing.

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.

Fingerprints of a New Normal Urban Air Quality in S5P TROPOMI Tropospheric NO2 Observations

2021 ◽  
Author(s):  
Shobha Kondragunta
Keyword(s):  
United States ◽  
Air Quality ◽  
Unemployment Rate ◽  
Power Plants ◽  
The United States ◽  
Urban Air Quality ◽  
Urban Air ◽  
Nox Emissions ◽  
Percentage Increase ◽  
New Normal

<p>Most countries around the world took actions to control COVID-19 spread that included social distancing, limiting air and ground travel, closing schools, suspending sports leagues, closing factories etc., leading to  economic shutdown. The reduced traffic and human movement compared to Business as Usual (BAU) scenario was tracked by Apple and Android cellphone use; the data showed substantial reductions in mobility in most metropolitan areas.  We analyzed reductions in on-road mobile NOx emissions from light and heavy duty vehicles in four major metropolitan and one rural areas in the United States that showed a reduction in NOx mobile emissions from 9% to 19% between February and March at the onset of lockdown in the middle of March; between March and April, the mobile NOx emissions dropped further by 8% to 31% when lockdown measures were the most stringiest.  These precipitous drops in NOx emissions correlated well with tropospheric NO<sub>2</sub> column amount observed by Sentinel 5 Precursor TROPospheric Ozone Monitoring Instrument (S5P TROPOMI).  Further, the changes in TROPOMI tropospheric NO<sub>2</sub> across the continental U.S. between 2020 and 2019 correlated well with changes in on-road NOx emissions (r=0.78) but correlated weakly with changes in emissions from the power plants (r=0.44). These findings confirm that power plants are no longer the major source of NO<sub>2</sub> in the United States. We also examined correlation between increase in unemployment rate between 2020 and 2019 to decrease in tropospheric NO<sub>2</sub> amount.  The negative correlation indicates that with increased unemployment rate combined with telework policies across the nation for non-essential workers, the NO<sub>2</sub> values decreased at the rate of 0.8 µmoles/m<sup>2</sup> decrease per unit percentage increase in unemployment rate.  There is a substantial amount of scatter in the data with some cities such as Atlanta, Dallas, and Houston showing no noticeable trend in tropospheric NO<sub>2</sub> changes during the time period when unemployment rate increased from 6% to 12%.   We examined the trends in on-road and power plant emissions for five different locations (four urban areas and one rural area) and show that the changes in NOx emissions during the lockdown are detectable in TROPOMI tropNO2 data, the economic indicators are consistent with emissions changes, and the trends reversing with the removal of lockdown measures in the major metro areas have not come back to pre-pandemic levels.  The COVID-19 pandemic experience has provided the scientific community an opportunity to identify emissions reductions scenarios that created a new normal for urban air quality and if the environmental protection agencies should look at this new normal as a guidance for instituting new policies. </p>

Kinetics Modeling on NOx Emissions of a Syngas Turbine Combustor Using RQL Combustion Method

2019 ◽  
Author(s):  
Haoyang Liu ◽  
Wenkai Qian ◽  
Min Zhu ◽  
Suhui Li
Keyword(s):  
Gas Turbine ◽  
Residence Time ◽  
Air Flow ◽  
Nox Reduction ◽  
Outlet Temperature ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Kinetics Modeling ◽  
The Rich ◽  
Nox Control

Abstract To avoid flashback issues of the high-H2 syngas fuel, current syngas turbines usually use non-premixed combustors, which have high NOx emissions. A promising solution to this dilemma is RQL (rich-burn, quick-mix, lean-burn) combustion, which not only reduces NOx emissions, but also mitigates flashback. This paper presents a kinetics modeling study on NOx emissions of a syngas-fueled gas turbine combustor using RQL architecture. The combustor was simulated with a chemical reactor network model in CHEMKIN-PRO software. The combustion and NOx formation reactions were modeled using a detailed kinetics mechanism that was developed for syngas. Impacts of combustor design/operating parameters on NOx emissions were systematically investigated, including combustor outlet temperature, rich/lean air flow split and residence time split. The mixing effects in both the rich-burn zone and the quick-mix zone were also investigated. Results show that for an RQL combustor, the NOx emissions initially decrease and then increase with combustor outlet temperature. The leading parameters for NOx control are temperature-dependent. At typical modern gas turbine combustor operating temperatures (e.g., < 1890 K), the air flow split is the most effective parameter for NOx control, followed by the mixing at the rich-burn zone. However, as the combustor outlet temperature increases, the impacts of air flow split and mixing in the rich-burn zone on NOx reduction become less pronounced, whereas both the residence time split and the mixing in the quick-mix zone become important.

3-Way Catalyst Testing at VTT Energy

2003 ◽  
Author(s):  
John Sartain ◽  
Don Newburry ◽  
Mikko Pitkanen ◽  
Markku Ikonen
Keyword(s):  
Natural Gas ◽  
Phase 1 ◽  
Nox Reduction ◽  
Oil And Gas Industry ◽  
The United States ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Research Centre ◽  
Low Oxygen ◽  
Crossover Point

Emissions regulations on stationary, natural gas fired reciprocating engines are becoming increasingly tighter throughout the United States. In addition to lower NOx, CO and hydrocarbon limits, regulation of HAP (Hazardous Air Pollutant) emissions has become more prevalent. Rich burn (stoichiometric) natural gas engines are widely used in the oil and gas industry, as well as in distributed power generation. Due to the low oxygen content in the exhaust, these engines are suitable for 3-Way catalyst, which simultaneously reduces NOx and oxidizes CO and hydrocarbons. A series of 3-Way catalyst tests were conducted on a small natural gas engine at the VTT Technical Research Centre in Espoo, Finland. The overall goals of the testing were to determine the ability of various 3-Way catalysts to meet California emissions regulations and to gather data on HAPs emission reductions. The testing was carried out in two phases. In phase 1, several fresh catalysts were tested at the NOx/CO crossover point (i.e., the point where CO and NOx reduction percent is approximately equal) by using an air/fuel ratio controller to keep the exhaust oxygen level constant. Detailed emissions measurements of both regulated and unregulated emissions were taken. The measurements included NOx, CO, hydrocarbon species, CH2O, N2O, NH3, and H2. In phase 2, the effects of exhaust lambda variation on NOx and CO were studied in more detail, with aged catalyst. Also, different engine loads were tested to vary the space velocity and temperature. This paper describes the testing in more detail and presents some of the resulting data.

Analysis of the Characteristics of Low NOx Combustion Using Exhaust Gas Recirculation

2014 ◽  
Vol 700 ◽  
pp. 220-224
Author(s):  
Yan Liu ◽  
Feng Li Kang ◽  
Rong Liu ◽  
Chi Jia Li ◽  
Qing Yu Wang
Keyword(s):  
Combustion Process ◽  
The United States ◽  
Air Pollutant ◽  
National Bureau ◽  
Nox Emissions ◽  
Health It ◽  
Combustion Phase ◽  
Low Nox Combustion ◽  
Nitric Oxide Emissions ◽  
Gas Recirculation

NOx damages to the environment. It also endangers human body health. It has become a major air pollutant. Only the nitric oxide emissions could be reduced by the improvement of combustion. The economical and reasonable technical measures, which is through selecting rational parameters and combustion process, could decrease the formation of NOx in fuel combustion phase. According to the national bureau of statistics data released, the national NOx emissions will reach 29.14 million ~ 42.96 million t in 2030,what is more ,China will surpass the United States to be the world's largest NOx emissions country. Environmental pollution has become one of the main factors restricting the development of economy in China [1].

A Simple Gas Turbine Combustor NOx Correlation Including the Effect of Vitiated Air

1977 ◽  
Vol 99 (2) ◽  
pp. 145-152 ◽  
Author(s):  
D. A. Sullivan
Keyword(s):  
Gas Turbines ◽  
Laboratory Tests ◽  
Nox Reduction ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Gaseous Fuels ◽  
Fuel Flow ◽  
In Series ◽  
Data Points ◽  
Regenerative Cycle

A set of parametric laboratory tests are used to develop a simple NOx correlation. The correlation is then compared with over 100 data points from various gas turbines operating on liquid and gaseous fuels. The correlation agrees well with constant speed simple cycle and regenerative cycle NOx data. The effect of vitiated air on NOx emissions is also determined from full scale laboratory tests and machine data. The NOx correlation with vitiated air is used to demonstrate the NOx emissions from two combustors operated in series with a variable fuel flow split between them. The nonlinear effect of fuel-to-air ratio on NOx production is shown to be responsible for the NOx reduction which occurs when two combustors are operated in series as opposed to single combustor operation.

Development of a Liquid-Fueled, Lean-Premixed Gas Turbine Combustor

1993 ◽  
Vol 115 (3) ◽  
pp. 554-562 ◽  
Author(s):  
L. H. Cowell ◽  
K. O. Smith
Keyword(s):  
Gas Turbine ◽  
Performance Testing ◽  
Operating Conditions ◽  
Operating Parameters ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Design Variables ◽  
Lean Premixed ◽  
Annular Combustor ◽  
Injector Design

Development of a lean-premixed, liquid-fueled combustor is in progress to achieve ultra-low NOx emissions at typical gas turbine operating conditions. A filming fuel injector design was tested on a bench scale can combustor to evaluate critical design and operating parameters for low-emissions performance. Testing was completed using No. 2 diesel. Key design variables tested include premixing length, swirler angle, injector centerbody diameter, and reduced liner cooling. NOx emissions below 12 ppmv at 9 bar pressure were measured. Corresponding CO levels were 50 ppmv. An optimized injector design was fabricated for testing in a three injector sector of an annular combustor. Operating parameters and test results are discussed in the paper.

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