The main function of a pyroscrubber in petroleum coke calcining process is to oxidize the carbonaceous contents, including hydrocarbon volatiles, of the exhaust gas from the calcination kiln, so as to leave no more than small traces of unburned volatiles, solid carbon, ashes, or emissions (e.g. CO, NOx and SOx) in the flue gas finally discharged. To maximize the energy recovery and reduce pollutant emission from the pyroscrubber, 3-D computational models are developed using FLUENT to simulate the combustion and thermal-flow phenomena inside the pyroscrubber. The results show the 3-D behavior of the flow, the reaction inside the pyroscrubber, effect of different amounts of air injection with respect to combustion efficiency, energy output and NOx emission. A multistage burning strategy is introduced and studied and results show it successfully cuts emission without compromising energy output. A particle combustion model with the homogeneous gas combustion model is also developed and incorporated to investigate CO emission.

D.L. A 128-2008

Insufficient knowledge of fireside behavior in the near-burner region during biomass combustion is one of major factors preventing widespread use of this renewable fuel in pulverized coal power plants. The current research is aimed to investigate the impact of biomass cofiring on NO formation in the near-burner region through interpretation of computational fluid dynamics (CFD) predictions and data collected from a series of biomass tests in a pilot-scale (0.2 MW), swirling flow burner. Two-dimensional gas species mole fraction data were collected with state-of-theart instruments from nine experiments, composing one herbaceous biomass (straw), one woody biomass (sawdust), a low sulfur sub-bituminous coal (Blind Canyon) and a high sulfur bituminous coal (Pittsburgh #8) and their mixtures of different mass fractions with the same swirl setting. Velocity and temperature are calculated from CFD modeling with FLUENTTM, supplemented with hot-wire anemometer measurements. For the first time, a reverse flow region was predicted during solid fuel combustion simulations for the reactor used. Interpretation of the results was carried on with two original methods: stoichiometric maps and normalized species mole fraction profiles. The impacts of biomass on combustion in the swirling flows were analyzed from several aspects: aerodynamics, fuel properties (particle size, volatile content, and fix-carbon content), and NO formation routes. The species maps show the low-grade fuel combustion under swirling flows is composed of two zones: a high species-gradient combustion region attached to the inlet and flat-profiles dominant across the rest of the reactor. Results from tests involving biomass clearly demonstrate the expansion of the combustion region. CFD calculations demonstrate that there is no obvious alteration of the reverse-flow region by biomass combustion. The larger average particle size of biomass generates a combustion region with further penetration into the reactor. In certain tests involving biomass, more NH3 than HCN was detected in several biomass experiments, though limited by the data collection method and low fuel-nitrogen fuels used (sawdust). Supplemented with kinetic calculations with CHEMKIN, it was found that NO formation is dependent on the nitrogen forms in the parent fuels.

<p>In today’s industrial world, there are high demands on the environmental aspects.</p><p>Siemens Industrial Turbomachinery AB (SIT AB) is a company that is keen about the environment, and therefore spends a lot of effort in developing combustion processes in order to reduce NOx (nitrogen oxides) emissions on their engine products. They are also researching in optional fuels, which are more environment-friendly.</p><p>In order to provide lower emissions the SIT designed a water rig to study the flow dynamics in a DLE (Dry Low Emission) burner.</p><p>An analyze program (GUI horizontal) was developed with new functions and the existing functions were improved. The program’s function was to evaluate different experimental tests of the flow dynamics in the 3rd generation DLE burners, of the SGT-800 gas turbine engine.</p><p>The aim was to ensure repeatability to enhance reliability, of the experimental test results for further comparison, for upcoming projects concerning future DLE burners.</p><p>When repeatability was achieved, implementations of different geometrical modifications were performed in the 3rd generation DLE burner.</p><p>The reason of the geometrical alterations was to look over if better fuel air mixture could be obtained and accordingly (thus) to reduce hotspots in the burner and in that case reduce NOx emissions.</p>

Cattle biomass (CB) has been proposed as a renewable, supplementary fuel for co-firing and reburning. Reburning coal with CB has the potential to reduce NOx and Hg emissions from coal fired systems. The present research focuses on three areas of combustion: 1) Biomass reburning experiments are conducted to determine the optimum operating conditions for the NOx reduction using blends of coal and CB as reburn fuels. 2) Since CB contains higher ash contents compared to coals, the fouling behavior is also investigated under the transient and short-time operation. 3) Finally CB contains higher Cl compared to coals, which oxidizes Hg to HgCl2. To understand the Hg oxidation behavior, a fundamental study of Hg oxidation in coal combustion is conducted using a plug flow reactor (PFR). The main parameters investigated are types of the reburn fuel, reburn equivalence ratios (ERRBZ), O2 concentrations in the reburn gas, injection angles of the reburn fuel, cross-sectional geometries of the reburn nozzles, symmetric and asymmetric reburn injections, reburn heat inputs, baseline NOx concentrations, and presence and absence of the heat exchangers (HEX). The results of reburning show that CB is a very effective fuel in NOx reduction, and the extent of NOx reduction is strongly dependent to the ERRBZ. The optimum conditions of the boiler operation for biomass reburning are as follows: ERRBZ = 1.1, 45° upward circular reburn nozzles, 12.5% O2 in the reburn gas, symmetric injection, and presence of HEXs. To make an effective reburn process, the baseline NOx concentrations must be higher than 230 g/GJ (0.5 lb/mmBTU) and the reburn heat input higher than 20%. The results of ash fouling show the presence of ash in the hotter region of the furnace seems to promote heat radiation thus augmenting the heat transfer to the HEX. The growth of the layer of ash depositions over longer periods typically lowers overall heat transfer coefficients. The addition of HCl to Hg containing gases in the PFR significantly increases Hg oxidations. The addition of NO inhibited the overall reaction and shifted the reaction temperature higher while the addition of O2 promoted Hg oxidations and lowered the reaction temperature. For heterogeneous cases, the use of the VWT catalyst promotes the reduction of Hg0 and shifted the reaction temperatures lower than those for homogeneous cases.

Coal fired power plants produce NOx at unacceptable levels. In order to control these emissions without major modifications to the burners, additional fuel called reburn fuel is fired under rich conditions (10-30 % by heat) after the coal burners. Additional air called overfire air (about 20 % of total air) is injected in order to complete combustion. Typically reburn fuel is natural gas (NG). From previous research at TAMU, it was found that firing feedlot biomass (FB) as reburn fuel lowers the NOx emission at significant levels compared to NG. The present research was conducted to determine the optimum operating conditions for the reduction of NOx. Experiments were performed in a small scale 29.3 kW (100,000 BTU/hr) reactor using low ash partially composted FB (LA PC FB) with equivalence ratio ranging from 1 to 1.15. The results of these experiments show that NOx levels can be reduced by as much as 90% - 95 % when firing pure LA PC FB and results are almost independent of. The reburn fuel was injected with normal air and then vitiated air (12.5 % O2); further the angles of reburn injector were set normal to the main gas flow and at 45-degrees upward. For LA PC FB no significant changes were observed; but high ash PC FB revealed better reductions with 45-degrees injector and vitiated air. This new technology has the potential to reduce NOx emissions in coal fired boilers located near cattle feedlots and also relieves the cattle industry of the waste.

ABSTRACT According to the data of the Taiwan Air Quality Monitoring Network (TAQMN), the suspenden particulates decreases gradually with year at the Kao-Ping Air Quality Area, but the ozone increases with year and deteriorates. Therefore, the problem of the ozone is wating for solving at Kao-Ping Air Quality Area. Because the ground-level ozone has a relationship with NOx and VOC, they are thought to be the major precursors of the ozone. The concentration of the ozone is not linearly related with concentrations NOx and VOC. The precursors of the ozone affect the ground-level ozone, so the photochemical indicators are further developed in recent years. The photochemical indicators H2O2,HNO3 and NOy in this study in Kaohsiung area are analysed by criteria values (Sillman,1995 and 1997) and on-site sampling. The sampling sites are at Nan-Zih, Siao-Gang, Lin-Yuan and Chiao-Tou. The results can determine the major precursors forming ozone. In addition Smog Production Model (SPM) is also used to analyze the results. According to the analyses of the photochemical indicators, Nan-Zih, Siao-Gang, Lin-Yuan and Chiao-Tou are VOC-limited in the spring, summer, fall and winter.According to the analysis result of SPM, the four sites are also VOC-limited in four seasons.

The focus of this research was the examination of the emission and transformation of nitrogen oxides emitted from vehicles. Measured data for this experiment were collected from May 1 thru May 31, 2002, and were compared to values modeled with CALINE4. CALINE4 is a photochemical and dispersive model used to predict concentrations of NOX (NO+NO2) from line sources. The measurement campaign was coincident with the Bay Regional Atmospheric Chemistry Experiment (BRACE). An ambient air quality monitoring site was constructed adjacent to Gandy Boulevard, in Tampa, FL. When comparisons of measured and modeled NO and NO2 values were made it was found that CALINE4 underpredicted NO2; i.e., underpredicted the conversion of NO, for both daytime and nighttime conditions. Possible causes of this bias were investigated and it was found that the simple kinetic mechanism present in CALINE4 was not sufficient to account for all of the reactions occurring. A simulation was run with a more comprehensive NO conversion mechanism and it was found that the reactions containing peroxy radicals affected the conversion rate but were not present in the simple CALINE4 mechanism. The simulation runs suggested that the ratio of radicals to O3 remained nearly constant during the course of the reaction. This pointed to an improved mechanism where the photolytic rate constant in CALINE4 could be replaced with a new constant, keff. This brought theday time calculations within reasonable agreement of the measured values, including an unexpected improvement in nighttime concentrations. Specifically, this modification eliminated the negative fractional bias in calculated daytime NO2 concentrations, moving it from -0.16 to 0.043. The fractional bias in nighttime calculations was improved from -0.17 to -0.036. Average hourly traffic counts were then used as inputs to the model to compare to the entire month of May 2002 data and it was found that the daytime fractional bias was improved from -0.27 to -0.06 and the nighttime from -0.35 to -0.24

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant inherited neurodegenerative disease for which there is no cure. SCA7 belongs to the group of polyglutamine disorders, which are all caused by the expansion of a polyglutamine tract in different disease proteins. Common toxic mechanisms have been proposed for polyglutamine diseases; however the exact pathological mechanism(s) are still unclear. The aim of this thesis was to identify and characterize the molecular mechanisms by which polyglutamine expansion in the ATXN7 protein cause SCA7 and how this can be counteracted. We found that mutant ATXN7 can be degraded by the ubiquitin proteasome system (UPS) and autophagy, the two main cellular degradation pathways. However aggregation stabilized the protein against degradation. Moreover, we found that mutant ATXN7 blocked the induction of autophagy by interfering with p53 and the ULK1-ATG13-FIP200 complex. Pharmacological stimulation of autophagy ameliorated aggregation, as well as toxicity. We also found that oxidative stress plays an important role in mutant ATXN7 toxicity and that the oxidative stress is generated by activation of NADPH oxidase 1 (NOX1) complexes. Furthermore, we showed that the increased NOX1 activity, together with polyQ expanded ATXN7 mediated disruption of the transcription factor p53, results in metabolic alterations in SCA7 cells. The expression of key p53 regulated metabolic proteins like AIF, TIGAR and GLUT1 was altered in SCA7 cells and resulted in reduced mitochondrial respiration, a higher dependence on glycolysis and reduced ATP levels. In summary, our data indicate that mutant ATXN7 mediated dysregulation of p53, resulting in autophagic and metabolic alterations, could play a key role in SCA7 and possibly other polyglutamine diseases.

In today’s industrial world, there are high demands on the environmental aspects. Siemens Industrial Turbomachinery AB (SIT AB) is a company that is keen about the environment, and therefore spends a lot of effort in developing combustion processes in order to reduce NOx (nitrogen oxides) emissions on their engine products. They are also researching in optional fuels, which are more environment-friendly. In order to provide lower emissions the SIT designed a water rig to study the flow dynamics in a DLE (Dry Low Emission) burner. An analyze program (GUI horizontal) was developed with new functions and the existing functions were improved. The program’s function was to evaluate different experimental tests of the flow dynamics in the 3rd generation DLE burners, of the SGT-800 gas turbine engine. The aim was to ensure repeatability to enhance reliability, of the experimental test results for further comparison, for upcoming projects concerning future DLE burners. When repeatability was achieved, implementations of different geometrical modifications were performed in the 3rd generation DLE burner. The reason of the geometrical alterations was to look over if better fuel air mixture could be obtained and accordingly (thus) to reduce hotspots in the burner and in that case reduce NOx emissions.