scholarly journals Hybrid technology of reduction of nitrogen oxides (NOx) in exhaust gases; Part 2 – Numerical model of pilot scale regenerative rotary air heater (RAH) retrofited with selective catalyst reduction (SCR) modules

2019 ◽  
Vol 82 ◽  
pp. 01016 ◽  
Author(s):  
Andrzej Kwiczala ◽  
Robert Wejkowski
Keyword(s):  
Numerical Model ◽  
Flue Gas ◽  
Catalytic Reduction ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Air Heater ◽  
Exhaust Gas Temperature ◽  
Heat Exchange Efficiency ◽  
Flue Gas Denitrification

This article exhibits the results of the analysis performed to verify the effectiveness of the hybrid flue gas denitrification system (herein referred to as HDS) which involved the retrofitting for selective catalytic reduction (SCR) material into a regenerative rotary air heater (RAH). A numerical model corresponding to the actual pilot scale RAH operating conditions was developed. The ultimate intent of the numerical model is to provide a platform where the technology can be implemented on full scale air preheaters. The numerical analysis performed on the pilot scale HDS installation showed a 3% decrease in heat exchange efficiency in the exchanger. This decrease was significantly minimized by the use of blades adjusting the distribution of flue gases entering the RAH. This means that the exhaust gas temperature at the exchanger outlet increased by 4°C, which corresponds to an average of 0.3% increase in the boiler outlet loss. It was also recognized that the air temperature was reduced by 8°C, which does not translate into significant changes in boiler performance parameters. other boiler operating parameters in a noticeable way during operation.

Enhanced Selective Non-Catalytic Reduction (SNCR) for Refinery Applications: Pilot-Scale Test Data With a Hydrogen Promoter

2011 ◽  
Author(s):  
Larry Swanson ◽  
Wei Zhou ◽  
David Moyeda ◽  
Christopher Samuelson
Keyword(s):  
Flue Gas ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Pilot Scale ◽  
Gas Temperature ◽  
Wide Range ◽  
Lower Temperature Range ◽  
Scale Test ◽  
Lower Temperature ◽  
Pilot Scale Test

Selective non-catalytic reduction technology (SNCR) is an effective and economical method of reducing NOX emissions for a wide range of industrial combustion systems. It is widely known that the traditional SNCR temperature window is centered around 1,200 to 1,255 K [1]. However, for some applications, the flue gas temperatures in boilers, oxidizers, and heaters range from 950 to 1150 K. At these lower temperatures, injection of an amine reagent into flue gas no longer actively reduces NOX, but instead passes through the system and exits as ammonia slip. Earlier studies have shown that at lower temperatures, hydrogen and other promoters can be added to the system to shift the SNCR window to a lower temperature range, enhancing or promoting SNCR NOX reduction performance [2–5]. This extended abstract describes pilot-scale test results for an enhanced SNCR process (ESNCR) that uses hydrogen as the SNCR promoter. The impacts of flue gas temperature, hydrogen concentration, CO concentration, and SO2 concentration on ESNCR NOX reduction performance are presented.

scholarly journals Numerical Analysis on the Flue Gas Temperature Maintenance System of a Solid Fuel-Fired Boiler Operating at Minimum Loads

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4420
Author(s):  
Michalina Kurkus-Gruszecka ◽  
Piotr Krawczyk ◽  
Janusz Lewandowski
Keyword(s):  
Flue Gas ◽  
Catalytic Reduction ◽  
Gas Temperature ◽  
Gas Streams ◽  
Different Temperatures ◽  
Flap Design ◽  
Lower Load ◽  
Higher Temperature ◽  
High Level ◽  
Exhaust Gas Temperature

Currently, energy policy is associated with the increase in the share of renewable sources in systemic energy production. Due to this trend, coal-fired power units must increase their work flexibility. Adapting a coal power plant to work with a lower load often causes the issue of maintaining the temperature before the selective catalytic reduction (SCR) installation at a sufficiently high level. This paper presents a CFD analysis of the mixing area of two flue gas streams before the SCR installation with various methods for mixing flue gas streams. The novelty of the work is mixing the flue gas streams of different temperatures using a flap shape developed by the authors. A series of numerical simulations were performed to develop the location and method of introducing the higher temperature gas, obtaining a uniform distribution of the exhaust gas temperature. The simulation scheme was applied to a series of geometrical modifications of the boundary conditions. The tested solution using only a single, straight flap in the flue gas duct allows the amplitude to be reduced from 298 K to 144 K. As a result of the research, a mixing flap design was developed to reduce the initial temperature amplitude of the flue gas streams from 298 K to 43 K.

scholarly journals Reliable simple zonal method of the furnace thermal calculation

2005 ◽  
Vol 9 (2) ◽  
pp. 45-55
Author(s):  
Vladan Ivanovic
Keyword(s):  
Energy Consumption ◽  
Flue Gas ◽  
Thermal Load ◽  
Operating Conditions ◽  
Thermal Calculation ◽  
Gas Temperature ◽  
Zonal Method ◽  
One Dimensional ◽  
Furnace Performance ◽  
Steam Boilers

The calculation of the furnace in the industrial and power boilers is the most important and the most responsible part of the thermal calculation, and it has important influence on the rationalization of energy consumption. In the paper one-dimensional zonal method of the furnace thermal calculation of steam boilers is presented. It can successfully define disposition of flue gas temperature and specific thermal load of screen walls with height of the furnace in case of uneven deposits distribution which vary in size and quality. Its greatest use is for comparing furnace performance under various operating conditions.

Effect of Fuel Injection Strategy on DPF Regeneration in Single Cylinder Diesel Engine

2015 ◽  
Author(s):  
Sungjun Yoon ◽  
Hongsuk Kim ◽  
Daesik Kim ◽  
Sungwook Park
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Experimental Results ◽  
Exhaust Gas ◽  
Post Injection ◽  
Gas Temperature ◽  
Injection Strategy ◽  
Dpf Regeneration ◽  
Exhaust Gas Temperature

Stringent emission regulations (e.g., Euro-6) force automotive manufacturers to equip DPF (diesel particulate filter) on diesel cars. Generally, post injection is used as a method to regenerate DPF. However, it is known that post injection deteriorates specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration becomes one of key technologies for diesel powertrain equipped with a DPF. This paper presents correlations between fuel injection strategy and exhaust gas temperature for DPF regeneration. Experimental apparatus consists of a single cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, post injection timing covers from 40 deg aTDC to 110 deg aTDC and double post injection was considered. In addition, effects of injection pressures were investigated. The engine load was varied from low-load to mid-load and fuel amount of post injection was increased up to 10mg/stk. Oil dilution during fuel injection and combustion processes were estimated by diesel loss measured by comparing two global equivalences ratios; one is measured from Lambda sensor installed at exhaust port, the other one is estimated from intake air mass and injected fuel mass. In the present study, the differences in global equivalence ratios were mainly caused from oil dilution during post injection. The experimental results of the present study suggest an optimal engine operating conditions including fuel injection strategy to get appropriate exhaust gas temperature for DPF regeneration. Experimental results of exhaust gas temperature distributions for various engine operating conditions were summarized. In addition, it was revealed that amounts of oil dilution were reduced by splitting post injection (i.e., double post injection). Effects of injection pressure on exhaust gas temperature were dependent on combustion phasing and injection strategies.

Utilization of Fly Ash Contaminated by SNCR Flue Gas Denitrification into Polymer Epoxy Anchor

2018 ◽  
Vol 776 ◽  
pp. 98-103
Author(s):  
Tomáš Žlebek ◽  
Jakub Hodul ◽  
Rostislav Drochytka
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Epoxy Resins ◽  
Catalytic Reduction ◽  
Physical And Mechanical Properties ◽  
Polymer Materials ◽  
Problematic Use ◽  
Different Types ◽  
Flue Gas Denitrification

The paper deals with the possibility of using two different types of fly ash contaminated by flue gas denitrification (Selective Non-Catalytic Reduction (SNCR)) as a filler into the polymer anchor based on epoxy resin. Due to the problematic use of contaminated fly ash in silicate materials, the use of such fly ash in polymer materials seems to be effective because by mixing with polymers such as polyester and epoxy resins, toxic gas ammonia (NH3) does not release. Determination of optimal percentage of filling by the fly ash was performed in order to achieve the best possible physical and mechanical properties of the epoxy anchor material. It was found out that the 45% addition of both used of contaminated fly ashes seems to be the most appropriate, when the polymer anchor material exhibited better tensile properties than reference anchors containing quartz sand Dorsilit. Furthermore, it was found that the optimal addition of contaminated fly ash also positively influenced the maximum anchoring force found in the tug test. Detailed connection of anchor material with anchored bar and concrete was observed on tomography images.

Effect of the Fuel Injection Strategy on Diesel Particulate Filter Regeneration in a Single-Cylinder Diesel Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Sungjun Yoon ◽  
Hongsuk Kim ◽  
Daesik Kim ◽  
Sungwook Park
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Diesel Particulate ◽  
Injection Strategy ◽  
Dpf Regeneration ◽  
Exhaust Gas Temperature

Stringent emission regulations (e.g., Euro-6) have forced automotive manufacturers to equip a diesel particulate filter (DPF) on diesel cars. Generally, postinjection is used as a method to regenerate the DPF. However, it is known that postinjection deteriorates the specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration is one of the key technologies for diesel powertrains equipped with a DPF. This paper presents correlations between the fuel injection strategy and exhaust gas temperature for DPF regeneration. The experimental apparatus consists of a single-cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, the postinjection timing was in the range of 40 deg aTDC to 110 deg aTDC and double postinjection was considered. In addition, the effects of the injection pressure were investigated. The engine load was varied among low load to midload conditions, and the amount of fuel of postinjection was increased up to 10 mg/stk. The oil dilution during the fuel injection and combustion processes was estimated by the diesel loss measured by comparing two global equivalences ratios: one measured from a lambda sensor installed at the exhaust port and one estimated from the intake air mass and injected fuel mass. In the present study, the differences of the global equivalence ratios were mainly caused by the oil dilution during postinjection. The experimental results of the present study suggest optimal engine operating conditions including the fuel injection strategy to obtain an appropriate exhaust gas temperature for DPF regeneration. The experimental results of the exhaust gas temperature distributions for various engine operating conditions are discussed. In addition, it was revealed that the amount of oil dilution was reduced by splitting the postinjection (i.e., double postinjection). The effects of the injection pressure on the exhaust gas temperature were dependent on the combustion phasing and injection strategies.

The Effect of Engine Exhaust Temperature Modulations on the Performance of Automotive Catalytic Converters

2006 ◽  
Author(s):  
Tariq Shamim
Keyword(s):  
Single Channel ◽  
Catalytic Converter ◽  
Space Velocity ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Engine Exhaust ◽  
Exhaust Temperature ◽  
Automotive Catalytic Converters ◽  
Exhaust Gas Temperature ◽  
Harmful Effects

This paper presents a computational investigation of the effect of exhaust temperature modulations on an automotive catalytic converter. The objective is to develop a better fundamental understanding of the converter’s performance under transient driving conditions. Such an understanding will be beneficial in devising improved emission control methodologies. The study employs a single-channel based, one-dimensional, non-adiabatic model. The transient conditions are imposed by varying the exhaust gas temperature sinusoidally. The results show that temperature modulations cause a significant departure in the catalyst behavior from its steady behavior, and modulations have both favorable and harmful effects on pollutant conversion. The operating conditions and the modulating gas composition and flow rates (space velocity) have substantial influence on catalyst behavior.

scholarly journals The Causes Analysis of the Air Preheater and Performance Blocking Evaluation of the Measures on the SCR De-NOx Unit

2019 ◽  
Vol 118 ◽  
pp. 03056
Author(s):  
Su Pan ◽  
Pengfeng Yu ◽  
Linbo Liu ◽  
Jing Han ◽  
Xiao Shen
Keyword(s):  
Flue Gas ◽  
Differential Pressure ◽  
Control Measures ◽  
Gas Temperature ◽  
Air Preheater ◽  
Environment Temperature ◽  
Ammonium Bisulfate ◽  
And Performance ◽  
Exhaust Gas Temperature ◽  
Ammonia Injection

In order to solve the problem of abnormal rise of the differential pressure of the revolving air preheater on 300MW unit, we analysed the causes of abnormal rise of the differential pressure of the air preheater and evaluated performances of control measures, through historical data mining and on-site inspection of the unit. The results show that, with the gradual decrease of environment temperature with the decrease of the exhaust gas temperature, the ashes in flue gas are bound by acid liquid produced by condensation of flue gas, and the adhesion areas of the ammonium bisulfate produced in the denitration process are enlarged. However the original set ash blowing pressure can no longer satisfy the requirements of the air preheater, giving rise to the differential pressure of the air preheater on both sides to rise. The reason of the higher differential pressure of the unilateral air preheater is that the large ammonia injection amount, leading to the increases of ammonia escape of the denitrification system. So the side of the air on preheater ammonium bisulfate type blockage is more serious. After the Measures of Adjusting distribution coefficient of ammonia supply valve on both sides, increasing the dust blowing frequency and pressure of the air preheater, the differential pressure of air preheater on both sides are close to the consistent. The decrease amplitude of the differential pressure of the air preheater on 280MW is about 300-500Pa.

scholarly journals Ammonia in Fly Ashes from Flue Gas Denitrification Process and its Impact on the Properties of Cement Composites

Buildings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 225 ◽  
Author(s):  
Agnieszka Michalik ◽  
Joanna Babińska ◽  
Filip Chyliński ◽  
Artur Piekarczuk
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Coal Combustion ◽  
Catalytic Reduction ◽  
Structural Features ◽  
Cement Composites ◽  
Fly Ashes ◽  
Ammonia Content ◽  
Denitrification Process ◽  
Flue Gas Denitrification

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of fly ash: Silica fly ash from flue gas denitrification and ash from a traditional boiler without the flue gas denitrification process. The scope of comparative studies included physicochemical and structural features of ashes, as well as slurries and mortars with the addition of ashes. Fly ash from denitrification, whose ammonia content at the time of sampling was 75 mg/kg at the maximum, was examined. Our own research has shown that fly ash from flue gas denitrification is characterized by a higher value of losses on ignition and ammonia content in comparison to ashes without denitrification. It was shown that the ammonia content in the analyzed range does not limit the use of fly ash as an additive to cement and concrete.

Applying the X-Ratio Correction to Calculated Air Heater Efficiency: An Alternate Method

2010 ◽  
Author(s):  
David C. McLaughlin ◽  
Joseph R. Nasal
Keyword(s):  
Heat Capacity ◽  
Heat Exchanger ◽  
Correction Factor ◽  
Mass Flow ◽  
Flue Gas ◽  
Correction Method ◽  
Gas Temperature ◽  
Original Design ◽  
Air Heater ◽  
The Impact

ASME PTC 4.3 on testing Air Heaters provides guidance for the calculation of gas-side efficiency as a measure of air heater performance. This code also provides for calculation of air heater X-ratio (XR), which is the ratio of the heat capacity (mass flow times specific heat capacity) of the air flowing through the heater to that of the flue gas. The code acknowledges the impact of XR on air heater efficiency, and dictates that the gas temperature leaving the air heater (and hence, air heater efficiency) be corrected for deviation from design XR by the use of “appropriate design correction curves” [1]. Unfortunately, such curves are rare, and therefore this important correction is usually ignored in routine air heater test calculations by power plant testing personnel, resulting in an incorrect calculation of air heater efficiency. This is particularly true for balanced draft boilers burning coal that are aged and have a significant amount of air leakage into the boiler setting. On these boilers, the ratio of combustion flue gas mass flow to combustion air mass flow is changed significantly from the original design, and therefore applying an XR correction factor is essential to calculating and reporting accurate air heater efficiency. This paper presents a method to calculate and correct for a deviation from design X-ratio based on standard heat exchanger analysis techniques, namely the ε-NTU method, which utilizes the concept of heat exchanger effectiveness (ε). A solution that results in applying the ratio of the design to actual XR’s as the correction factor is developed. The paper also provides empirical data from testing on a coal-fired boiler to validate the alternate correction method.

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