Flue Gas

In the article, it is considered for the establishment of the water-chemical regime on the DE 25/14 boiler, before starting alkaline washing with solutions of sodium hydroxide and sodium phosphate. The boiler washing procedure was carried out in five stages. After the end of flushing, the volume of flushing water was experimentally determined at various pressures. The article also sets out to establish the optimal mode of combustion of a mixture of gas and fuel oil in furnaces and performed heat engineering tests to determine the consumption of ammonia when cleaning flue gases from sulfur oxide, and also proved a decrease in the concentration of sulfur oxides.

Diplomová práce se zabývala výzkumem effervescent trysek. Effervescent trysky patří do skupiny dvoufázových rozprašovacích trysek, které se často využívají ve spalovacích aplikacích. Právě ve spalovacích aplikacích má míra stability spreje významný vliv na účinnost spalování a množství vzniklých exhalací. Hlavním cílem práce bylo zhodnotit míru nestabilit spreje v závislosti na konstrukci trysky a jejím provozním režimu. Vliv konstrukce byl zkoumán v závislosti na průměru a délce směšovací komory, a dále pak na velikosti, počtu a rozmístění aeračních otvorů. Různými kombinacemi těchto konstrukčních parametrů vzniklo 17 specifických variant zkušebních vzorků trysky. Každá tato varianta byla proměřena ve třech provozních režimech, reprezentovaných určitým tlakem kapaliny na vstupu do trysky a hmotnostním poměrem průtoku plynu ke kapalině (GLR). Pro vyhodnocení míry nestabilit spreje byla požita metodika, která porovnává ideální rozdělení částic do mezičásticových časových tříd, defino...

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Alkali metal atoms, especially sodium and potassium, show an intense fluorescence in hot flue gases. The bright fluorescence emitted by alkali metal atoms offers a large potential for spectroscopic combustion analysis. In this thesis, the temperature dependence of the two-component fluorescence intensity ratio Na/K, as well as the three-component ratio Na·Li/K2 was investigated in the flames with known relative concentrations of seeded alkali elements. A theoretical simulation based on thermal radiation excitation was performed to describe the temperature dependence of fluorescence intensity ratios Na/K and Na·Li/K2 in burned gas region. However, measurements show that the two-component fluorescence intensity ratio Na/K is pretty sensitive to the gas temperature whereas the three-component ratio Na·Li/K2 is less temperature dependent. The hot flue gas environment was provided by a modified Perkin-Elmer burner and the alkali metal atoms (Na, K, and Li) were provided through Na2CO3, K...

Steam and electricity needs in the paper industry have been provided itself through coal-fired boiler equipped with emission control devices. Boiler flue gas emissions of coal combustion products contain contaminants such as particulate emissions , NO2 and SO2 , and a small amount of emissions of mercury (Hg). Valuation on boiler emissions quality associated with air emissions control systems and emissions standard has been carried out. Estimation of mercury concentration in air emissions of boiler flue gas in the paper industry has also been conducted. The valuation on the air emissions quality of non-mercury parameters of paper industry boilers has also been done based on national emissions standards. The results of the valuation indicated that the current applied of flue gas emissions control devices in the paper industry has been optimally operated so that the emission quality of boiler for both non-mercury parameters and mercury parameters has been complied with the emission qu...

ABSTRAK Boiler merupakan  suatu  pembangkit  uap  yaitu  yang  terdiri  dari  kombinasi komplek berupa economizer, ketel, pemanas lanjut, pemanas ulang, dan pemanas udara awal.   Sebagai tambahan sistem ini, khususnya yang dengan bahan bakar batubara, mempunyai berbagai perlengkapan seperti ruang bakar,  pulverizer , pembakar,  fan , perlengkapan pengendali emisi, cerobong, dan peralatan penanganan abu. Ketel uap   dapat diklasifikasikan berdasarkan beberapa jenis yaitu : Ketel tangki ( shell type boiler ) Ketel Pipa Api, Ketel pipa air.   Bahan bakar padat yang terdapat di bumi kita ini berasal dari zat-zat organik.  Fibre dan cangkang merupakan salah satu contoh bahan boiler padat. setiap bahan bakar boiler memiliki nilai LHV yang berbeda-beda.  Nilai Low Heating Value tertinggi dimiliki oleh bahan bakar boiler jenis cangkang murni dengan nilai 44184,391Kcal/Kg sedangkan untuk nilai LHV bahan bakar boiler yang terkecil dimiliki oleh bahan bakar boiler jenis fibre murni dengan nila...

Erosion by coal particles, fly ash impingement seriously affects the availability of utility boilers. Erosion is predominant in economizer and low temperature superheaters (LTSH) in boiler tube banks. Three tube specimens were collected from NTPC Korba from first row of economizer top bank from 500 MW steam generator. Maximum depth of erosion anywhere on tube surface can be estimated by the erosion model proposed by Chinese Boiler Thermal Association. Erosion rates on tube surface can be estimated from impact velocity and impingement angle of ash particles in flue gas in the erosion model proposed by Hameed (1992). The maximum depth of erosion wear and erosion profile of tube specimens were compared with the values evaluated from both the models. Erosion coefficients of fly ash in gas, thus achieved have good agreement with value proposed in the literature. The predicted erosion rates have resemblance, though not coherently with the erosion profile of tube specimens. Collision effic...

Transesterification of soybean oil (O) with glycerol (G), catalysed by Novozym 435, was studied in tert-butyl alcohol as solvent. The effects of reaction tempe¬rature (40–50 °C), solvent concentration (20–35 vol.%), G/O molar ratio (1:1 – 2:1), and residence time (min) on the oil phase composition (tri- (TAG), di- (DG) and monoacylglycerol) were evaluated. DAG formation was preferred at lower temperatures, lower G/S mole ratios, and at higher solvent concentrations. The data for G/S = 2:1 agreed well with those obtained in a continous fixed-bed column reactor. Glycerolyses of olive, sunflower, rapeseed, and linseed oils are also reported. Higher reaction rates of continous processes compared with batch glycero¬lysis were observed.

A thermodynamic analysis is performed to investigate the performance of a Kalina cycle (KC) integrated with a standalone 400 MW pressurised pulverised combined cycle (PPCC). The KC extracts waste heat from the plant's flue gas exhaust. The thermodynamic analysis shows that the proposed integrated plant has an energy and exergy efficiencies of 44.56% and 40.88%, respectively. Moreover, KC generates an additional power of 8.89 MW with energy and exergy efficiencies of 12.25% and 33.81%, respectively. The economic study shows that the cost of electricity generation and payback period of KC are ₹2.24 per unit and 1.95 years, respectively.

Bench-scale carbon-catalyst tests were conducted in the first quarter of 2004, to obtain kinetic rates of mercury oxidation and sorption for different forms of carbon. The current quarterly report provides a more extensive quantitative analysis of the data obtained from the CRTF experiments on different carbon types and carbodcalcium mixtures than was presented in the last quarterly report. The procedure and basis for normalizing mercury removals, so that they could be compared on an equal residence time basis, is described. The chemisorption rate of mercury on carbon was found to be first order in mercury concentration and half order in HCI concentration, for the facility configuration investigated. The applicable temperature range of the kinetic rates obtained is from 300 OF to 700 "F, and the applicable chlorine concentration range is from 2 ppmv HCI to 250 ppmv HC1. The gas-sorbent contact time of 0.12 seconds used in this work was shown to be representative of gas-dust cake contact times in full-scale baghouses. All carbon types investigated behaved similarly with respect to Hg sorption, including the effect of temperature and chlorine concentration. Activated carbon was more effective at sorbing mercury than carbon black and unburned carbon (UBC), because the internal surface area of activated carbon is greater. The synergistic relationship between Ca and C is also discussed in the report.

The dust in the flue gases of a recovery boiler consists of two major fractions: a) coarse (10 1000 μm) carryover particles, generated from black liquor droplets carried over with the flue gases to the upper furnace, and b) submicron-sized fume, generated either from the smelt bed or at the pyrolysis stage of the black liquor combustion. The amount of the two dust fractions varies with location in the boiler. The highest amount of carry over particles are found in the upper furnace and superheaters. Fume is the dominating fraction in the colder parts of the flue gas channel.

The increasing emphasis on renewable energy sources has fostered interest in the use of biomass waste as a potential power source. Despite this, few studies have explored its application in powering drying machinery. This study presents the design, fabrication, and performance testing of a biomass-powered dryer, specifically developed for chili drying. The constructed dryer, featuring a drying box, biomass furnace, and flue gas passage, is distinguished by its simplicity, cost-effectiveness, and its capacity to operate during inclement weather due to its reliance on flue gas derived from biomass combustion. Given the rising culinary demand for chili powder, effective drying of chili prior to powdering is crucial. This research furthers this goal by conducting an energy and exergy analysis of the flue gas dryer, operating at varying flue gas velocities of 8, 13, 14, and 15.5 m/s, during the chili drying process. In addition, sustainability indicators such as the Waste to Energy Ratio (WER) and Sustainability Index (SI) were also investigated. Preliminary findings indicate that the biomass-powered dryer operates effectively under indirect-forced convection mode, with flue gas velocity significantly influencing the energy and exergy outcomes of the dryer. Peak efficiencies for both energy and exergy were found to be 22% and 23.99%, respectively, at a flue gas flow of 13 m/s.

The methodology for controlling the concentration of carbon dioxide in flue gases from boilers is an optical absorption method with improved metrological characteristics. Studies done in the article, provided the new, scientifically-based theoretical and practical results that are essential for improving the accuracy at the required speed process, control the carbon dioxide concentration in dual gas boilers based on the optical absorption method with compensation effect on the factors optical converter.

Metals released during fossil fuel use are important atmospheric pollutants. Mercury and other trace metals can be transferred to an aquatic environment through atmospheric deposition. In the work reported here, a number of sediment cores were retrieved from central Texas lakes in the proximity of a coal-fired power plant in search of local anthropogenic effects. Cores were collected along a transient parallel to the prevailing wind direction (S-SE) in the area. Trace element concentrations in the lignite and in effluents from the power plant showed that some elements remained constant (Al, Cu) throughout the different lignite combustion and power production processes. Some (like Cd and Se) showed an affinity for the smaller particles, whereas others (Hg) showed very low concentrations in all the solid wastes, indicating that they probably escaped with the flue gases. Sediment cores from a lake next to the power plant showed higher trace metal concentration in the upper part of the cores (more recent sediment). For example, there was as much as a tenfold increase in Hg concentration between the core bottom (10 ng/g), where the sediment was approximately 100 years old and the surface (100 ng/g). Cd and Se at surface sediments were also found to be as high as 1.6 and 3.45 g/g, respectively. The excess metal inventory was higher for the lakes located next to the power plant than for two lakes about 30 km away.

With sustainable energy being the key to reaching climate neutrality, the utilization of non-wooden biomass is a necessity. This article compares the emissions and efficiency of combusting a number of types of agrobiomass and wood pellets. A comparison was made on a moving grate pellet burner mounted in a boiler, where flue gas had a vertical flow via two pass heat exchangers with turbulization elements. Tests were conducted on wood pellets (ENPlus), miscanthus straw pellets, sunflower husk pellets, and corn stover pellets. During combustion, both wood and miscanthus pellets met the PN-EN 303-5:2012 emission and efficiency requirements. Corn stover pellets met the requirement on the nominal capacity. Sunflower husk pellets are characterized by excessive CO and particulate matter emissions. Sunflower husk pellets were the most problematic fuel from the point of view of the results of this research. During combustion of the miscanthus straw pellets there was a need to decrease the nom...

The concept of the new water treatment system was developed. The system is based on the previously invented technology -Compact Particulate Matter Collector (CPMC). A primary area was defined in which such technology is intended to be used: water treatment in compact flue-gas condensation systems for a low-power wood-fuelled biomass boiler. Such a system is intended for use in domestic conditions. Such a process involves contamination of technical water with a mixture of particulate matter, resulting in suspension. The CPMC aims to divide the suspension into the relevant fractions effectively. A prototype operating based on CPMC technology was built. An experimental plan was developed, and an experimental stand was constructed to determine the prototype's efficiency. The experimental plan envisaged five different prototype operating modes and two research steps, depending on the degree of prototype modification. Based on the research results, it was concluded that the prototype could operate effectively in the laboratory environment: achievable efficiency is equal on average between 57.84 % and 88.09 % depending on the operating mode (see the diagram below). The result is assessed as positive. TRL 3 has been reached. The next phases of the study would be the integration of the prototype into the relevant compact flue-gas condensation system and the exploration of commercialisation capabilities, which will stimulate TRL increase.

The concept of the new water treatment system was developed. A primary area was defined in which such technology is intended to be used: water treatment in compact flue-gas condensation systems for a low-power wood-fuelled biomass boiler. A prototype operating based on invented technology was built. An experimental plan was developed, and an experimental stand was constructed to determine the prototype’s efficiency. Based on the study’s results, it was concluded that the prototype could operate effectively in the laboratory environment: achievable efficiency is equal on average between 57.84 % and 88.09 % depending on the operating mode. The result is assessed as positive. TRL 3 has been reached.

Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.

Herein, we discuss possible ways to reduce the cost of carbon dioxide (CO 2 ) sequestration with a special focus on the process and the solvent used. Modifications to the process to eliminate the stripper section and focus on just the CO 2 adsorbing and geological dumping (CAGD) can lead to significant reductions in the sequestration cost per tonne of CO 2 compared with ordinary CO 2 capture and geological storage (CCS) processes. In the case of CAGD, savings of steam used in the ordinary CO 2 capture process can go up to US$12.7per ton of CO 2 captured and additional savings on the waste disposal cost of US$175/tonne of waste can be made. More savings on the energy costs for compression and cooling of the captured CO 2 gas can be realized if the absorbent and flue gas/CO 2 slurry is directly dumped in a geological formation. A change of the capture solvent can also make this process better economically by using the proposed substitute. Many commercially available alternatives to monoethanolamine (MEA) have been presented in this research by mainly focusing on how their loading capacity and cost compare. Aqueous Sodium carbonate (Na 2 CO 3 ) has been proposed as the best material for use in the CAGD CO 2 absorbing process based on the economic advantages it presents.

This research introduces a novel bent ring turbulator designed to enhance the heat transfer efficiency of a heated tube. Initially, various structural characteristics of the turbulator are analyzed, including its cross-sectional shapes (circular, square, and triangular) as well as bending angles, which range from 15° to 60°. Using the performance evaluation criterion (PEC), the optimal geometry of the turbulator is achieved, and subsequently, its rotating configuration is assessed. The arrangement of the rings in the bent ring turbulator features a designed rotating configuration, where each ring has an angular difference of
relative to the preceding ring. Investigations are conducted at various flow rates, with inlet Reynolds number ranging from 2573 to 6433. Results indicate that this turbulator can increase heat transfer and pressure drop by up to 291 % and 282 %, respectively, compared to a plain tube. Furthermore, the tube equipped with a bent ring turbulator of the triangular cross-section, featuring a bending angle of 30° and a rotation angle of 30°, is identified as the optimal configuration, achieving a PEC of 2.5.

Metal hydride materials offer attractive solutions in addressing problems associated with hydrogen separation and purification from waste flue gases. However, a challenging problem is the deterioration of hydrogen charging performances resulting from the surface chemical action of electrophilic gases. In this work, the feasibility study of poisoning tolerance of surface modified AB5-type hydride forming materials and their application for hydrogen separation from process gases containing carbon dioxide and monoxide was carried out. Target composition of La(Ni,Co,Mn,Al)5 substrate was chosen to provide maximum reversible hydrogen capacity at the process conditions. The selected substrate alloy has been shown to be effectively surface-modified by fluorination followed by electroless deposition of palladium. The surface-modified material exhibited good coating quality, high cycle stability and minimal deterioration of kinetics of selective hydrogen absorption at room temperature, from gas mixtures containing 10% CO2 and up to 100 ppm CO. The experimental prototype of a hydrogen separation unit, based on the surfacemodified metal hydride material, was tested and exhibited stable hydrogen separation and purification performances when exposed to feedstocks containing concentrations of CO2 1.

In northern countries, biofuel is widely used to provide centralized heating and electricity production. In Lithuania, use of biofuel is also currently increasing: it is used not only in industrial areas but is also as a popular type of fuel for small scale household furnaces. Although carbon dioxide, released during combustion of biofuel, is not treated as a gas causing the greenhouse effect, the main disadvantage of this type of fuel in comparison to combustion of some gaseous or liquid fuels is rather high emissions of coarse, fine and ultrafine solid particles. Long term exposure to such types of particulate matters causes health problems. Electrostatic precipitation is a very reliable method to control particulate emissions from boilers, incinerators, and other industrial processes. However, its application for small scale heat production appliances is still limited. The aim of this work is to evaluate the capability (efficiency) of a small scale electrostatic precipitator to capture solid particles emitted during incineration of wood pellets. Wood pellets were incinerated in an automatic boiler with the rated thermal output of 50 kW. During investigations, distributions of solid particles were measured in the chimney using infrared particle sizer which is able to measure particles in the range from 0.4 µm to 300 µm. Results showed that there are mainly solid particles in the flue gases with diameters from 0.4 µm to ~20 µm. Investigations were performed at different supply voltages to the discharge electrode of the electrostatic precipitator (ESP). This allowed determining collection of the particles by the ESP in case of different strength of the electrostatic field. In general, the total collection efficiency of ~99% was achieved.

Among various pollutants, mercury has a significant impact on the environment, human beings, and wildlife with its different forms, namely, elemental mercury (Hg 0), oxidized mercury (Hg 2+), and particle-bound mercury (Hg p). Mercury dispersions mainly occur from coal burning, which is the world's major energy source. Among the three forms, Hg 2+ and Hg p are relatively easy to remove from the flue gas by employing typical air pollution control devices; on the other hand, Hg 0 is difficult to remove. Various methods are available to detain elemental mercury. Recent developments in mercury removal options, especially during the last years, are reviewed. Main concentration has been focused on the removal methods of elemental mercury by novel sorbents and catalytic systems. A current challenge is to develop novel nanomaterials meeting rigorous requirements (easy separation, recyclability, and cost-effectiveness) for eventual exploitation.

O 2 /CO 2 CO 2 capture Aspen plus TM Air separation unit NGCC Amine scrubbing a b s t r a c t Reduction of greenhouse gas emissions is becoming essential for struggling against global warming. Priority has been given to sources where carbon dioxide (CO 2 ) emissions are the largest and the most concentrated. Power plants using fossil fuels offer a great opportunity of applying CO 2 recovery processes. The O 2 /CO 2 cycle is an interesting option since CO 2 concentration in the flue gas is highly increased. This cycle has been applied to a natural gas combined cycle (NGCC) using an advanced gas turbine (GE9H). The aim of this study is to assess by simulation the energy and environmental performances of this new type of power plant. The oxygen required is produced by an air separation unit (ASU) that can deliver oxygen with a purity ranging between 85 and 97 mol.%. A CO 2 recovery process based on a cryogenic separation of carbon dioxide from inert gases has been designed and assessed. The impact of CO 2 capture has been calculated with the Aspen plus TM software. With an O 2 purity of 90 mol.% and an 85% CO 2 recovery rate, the net electrical efficiency reaches 51.3% (based on the low heating value (LHV)). This corresponds to an efficiency loss of 8.1%-points in comparison with the base case. The quantity of avoided CO 2 is about 280 g kW À1 h À1 . These results have been compared with a conventional amine scrubbing applied to a NGCC. With a lean CO 2 loading of 0.16 mol CO 2 /mol amine, this process leads to a net electrical efficiency of 49.1% (LHV). The conversion into an O 2 /CO 2 cycle seems to be more efficient than amine scrubbing but more difficult to implement because of the specific gas turbine.

It has been suggested that various combinations of Blast Furnace Gas (BFG), COG, biogas, etc., for production of methanol  and  has recd interest world wide. These and other examples indicate that India's steel industry can not only be a producer of steel but can also be a producer of basic chemicals like methanol, ammonia, and downstream chemicals, using COG and BFG. The chemicals can be propylene, gasoline, LPG, acetic acid, isocyanates (TDI, MDI), ethyl carbonate, ethylene glycol, diphenyl carbonate, polycarbonate, etc. The intriguing part is that all these technologies are in commercial use. We are suggesting that COG and BFG be used to produce ammonia along with methanol.The potential is in millions of tons

The emission of large amounts of CO2 into the atmosphere is believed to be a major reason behind climate change, which has led to increased demand for CO2 capture. Postcombustion CO2 capture with chemical solvent is considered one of the most important technologies in order to reduce CO2 emission. Amino acid salt solutions have attracted special attention in recent years due to their excellent physicochemical properties, e.g., low volatility, less toxicity, and high oxidative stability, as well as capture performance comparable with conventional amines. In this study, physicochemical properties of 20 amino acids are reported and their CO2 absorption performance discussed. The topics covered in this review include the most relevant properties of amino acids including CO2 loading capacity, cyclic capacity, equilibrium constant, density, viscosity, dissociation constant, CO2 solubility, CO2 diffusivity, reaction kinetic between CO2 and amino acid salts, reaction rate constant, surface ...

Agglomeration of ash is a major issue in fluidized bed combustion boiler, large agglomeration decreases the bed mixing and result of this activity de-fluidisation take place in the boiler. This cause a shutdown of the combustor because of defluidization. In recent years, significant advances have been made in understanding and predicting the behavior of ash in combustion and gasification systems. In CFBC boilers ash sintering may contribute to deposit formation in the cyclone, return leg and post cyclone flue gas channel. Rapid sintering can lead to heavy agglomerate formation, which may finally inhibit circulation in dense phase areas (such as seal pot and return leg). Hence understanding the sintering behavior before the fuel is used, would be desirable for avoiding problems. A survey of ash agglomeration and deposit formation in industrial boiler found that all the boiler facing some form of bed ash agglomeration. In combustion using Indian coal having high percentage of sulphur ...

Although fluidized bed in situ desulphurization from coal combustion has been widely studied, there are aspects that remain under investigation. Additionally, few publications address Brazilian coal desulphurization via fluidized beds. This study used a 250 kWth bubbling fluidized bed pilot plant to analyze different aspects of the dolomite desulphurization of two Brazilian coals. Superficial velocities of 0.38 and 0.46 m/s, flue gas recycling, Ca/S molar ratios and elutriation were assessed. Results confirmed the influence of the Ca/S molar ratio and superficial velocity -SO 2 conversion up to 60.5% was achieved for one coal type, and 70.9% was achieved for the other type. A recycling ratio of 54.6% could increase SO 2 conversion up to 86.1%. Elutriation and collection of ashes and Ca-containing products did not present the same behavior because a lower wt. % of CaO was collected by the gas controlled mechanism compared to the ash.

The article presents the main aspects of the implementation, use and pilot and industrial experiments of some self-contained recovery burners. The results of pilot and industrial experiments of these burners have argued and quantified their energy efficiency. This efficiency consists mainly in an economy of specific fuel consumption (natural gas and / or coke gas) of approx. 25-35%. Other advantages of using recuperative burners are: ensuring a higher temperature in the hearth, reducing the duration of the processing cycle and thus increasing labor productivity. All these advantages of using recuperative burners are based on their operating principle, which consists in preheating the oxidizer (combustion air) by recovering an important part of the enthalpy of its own flue gases. This recovery is done in an energy recuperator designed right in the body of the recuperative burner. Due to this important aspect, the recovery burner is part of the Primary Energy Recovery (REP) category.

The main methods of reducing nitrogen oxides concentration in flue gases during the boiler plants operation are considered and analyzed. It was shown that simplified recirculation scheme with the flue gases supply into the inlet of the blower fan makes it possible to reduce emissions of nitrogen oxides at relatively low capital and operating costs. The aim of the work is to evaluate the impact of flue gases recirculation into the furnace on the technical, economic and ecological characteristics of the ship's auxiliary boiler. The research was carried out using the methods of computer simulation. A new data of the flue gases recirculation effect on the main characteristics of the ship auxiliary boiler Aalborg OM-TCi with a steam capacity of 20,0 t/h were obtained. It was found that the recirculation of flue gases in the range of 0 … 20 % leads to a decrease in the adiabatic temperature in the furnace by 273°C (from 1919 to 1646°C), the average integral temperature in the active combustion zone decrease from 1773 to 1534°C, and the temperature of gases at the outlet of the furnace decrease from 1300 to 1233°C. The boiler flue gas temperature rises from 225 to 236°C. An increase in heat losses with flue gases by 0,5% leads to a decrease of the boiler efficiency from 89,2 to 88,7%. The furnace heat absorption decreases by 999 kW and the heat absorption of convective steam-generating tube bundle increases by 900 kW. The decrease in the boiler steam output is 0,11 t/h. The recirculation coefficient in the range of 10 … 15% is recommended to choose on the basis of the study results. The given values of the recirculation coefficient correspond to an increase in the resistance of the gas-air path of the boiler by 25%, as well as a decrease in nitrogen oxide emissions by 44%.

In the study the most important and known polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) emission sources are presented and known methods of reduction of dioxin emission to the atmosphere are discussed in detail. It is indicated that the most relevant emission source is a combustion process. The mechanism of dioxin formation in thermal processes is presented in brief. The author characterized primary methods of reduction of PCDDs/PCDFs emission encompassing the interference into the combustion process to minimize their formation and discussed known secondary methods aimed at their removal from the stream of waste gases. It was attempted to make a critical assessment of PCDD/Fs reduction methods described in literature. International Journal of Chemical Engineering way dioxins and furans affect a human organism. Hence, all activities aimed at the restriction of the emission of dioxins to the atmosphere are fully justified.

Exploring the expansive and largely untapped chemical space of metal-organic frameworks (MOFs) holds promise for revolutionising the field of materials science. MOFs, hailed for their modular architecture, offer unmatched flexibility in customising functionalities to meet specific application needs. However, navigating this chemical space to identify optimal MOF structures poses a significant challenge. Traditional high-throughput computational screening (HTCS), while useful, is often limited by a distribution bias towards materials not aligned with the desired functionalities. To overcome these limitations, this study adopts a "deep dreaming" methodology to optimise MOFs in silico, aiming to generate structures with systematically shifted properties that are closer to target functionalities from the outset. Our methodology integrates property prediction and structure optimisation within a single interpretable framework, leveraging a specialised chemical language model augmented with attention mechanisms. Focusing on a curated set of MOF properties critical to applications like carbon capture and energy storage, our approach not only expands the selection of potential materials for HTCS but also opens new avenues for material exploration and development.

The problem is analyzed of hydrate formation in the systems of gathering and treating of oil and gas products. The methods are studied for prevention of complications associated with the gas hydrates accumulation in the pipelines and process lines. Attention is focused on the significant material costs to prevent the hydrate formation and ways to reduce them. The necessity of constant laboratory monitoring for reservoir systems at industrial facilities to determine the hydrate formation parameters has been substantiated. The need to improve the method for determining the hydrate formation parameters for complex reservoir systems based on a mixture of hydrate-forming gases has also been proved. The purpose of the work is to improve the research method of reservoir systems immediately at the facilities of products mining and treatment. The peculiarities are analyzed of the method of visual laboratory observation in the study of gas hydrates. During experimental studies, optical effect...

The objective of this research was to investigate the impact of increasing the CO 2 concentration in the exhaust flue gas in gas turbines via exhaust gas recirculation (EGR) and selective exhaust gas recirculation study (S-EGR). The gas turbine types explored are the micro gas turbine (MGT) and the combined cycle gas turbine (CCGT). Both gas turbines were integrated with a chemical absorption capture plant operated using MEA, in order to determine the reduction in carbon emissions into the atmosphere. Modelling the CCGT, involved a fuel flexibility study as well as a techno-economic analysis carried out to determine the cost of electricity (COE) and cost of CO 2 avoided (COA) to ascertain the economic and energy savings involved as well as the emission reductions. The study on the MGT, entailed the experimental and modelling analysis of S-EGR via CO 2 injection into the compressor inlet, with a maximum CO 2 injection flowrate of 300 kg/h. The experimental campaign carried out on the MGT and capture plant were based at the LCCC, in Sheffield. The performance of the MGT is investigated over a range of power outputs (100 kWe to 60 kWe) and the emission properties are recorded. It was observed that the CO 2 flue gas concentration increased from 1.8 mol% to 9.6 mol% and 1.5 mol% to 11.6 mol% at 100 kWe and 60 kWe respectively, which improved the performance of the integrated capture plant, indicating that S-EGR operation in the MGT could reduce the specific reboiler duty by 15% whilst increasing the liquid-gas ratio, at a constant capture rate of 90%, thus, reducing overall energy costs. The CCGT study entailed the modelling of fuel flexibility via increasing the CO 2 content in the fuel from a conventional natural gas composition with 1 mol% CO 2 to a maximum CO 2 content of 10 mol%. Then, an Exhaust Gas Recirculation (EGR) study, involving a 35% EGR ratio stream from the exhaust to the compressor inlet, in which the CO 2 content in both the fuel and the air were increased. In both studies, the CCGT is integrated to a capture plant, to reduce the emissions from the power plant. The results indicate that implementing EGR in a CCGT provides better working conditions for the integrated capture plant, when operating with various fuel compositions. The COE and COA associated with EGR implemented CCGT's are noticeably lower and thus proving its high energy savings and emission reductions.

The objective of this research was to investigate the impact of increasing the CO 2 concentration in the exhaust flue gas in gas turbines via exhaust gas recirculation (EGR) and selective exhaust gas recirculation study (S-EGR). The gas turbine types explored are the micro gas turbine (MGT) and the combined cycle gas turbine (CCGT). Both gas turbines were integrated with a chemical absorption capture plant operated using MEA, in order to determine the reduction in carbon emissions into the atmosphere. Modelling the CCGT, involved a fuel flexibility study as well as a techno-economic analysis carried out to determine the cost of electricity (COE) and cost of CO 2 avoided (COA) to ascertain the economic and energy savings involved as well as the emission reductions. The study on the MGT, entailed the experimental and modelling analysis of S-EGR via CO 2 injection into the compressor inlet, with a maximum CO 2 injection flowrate of 300 kg/h. The experimental campaign carried out on the MGT and capture plant were based at the LCCC, in Sheffield. The performance of the MGT is investigated over a range of power outputs (100 kWe to 60 kWe) and the emission properties are recorded. It was observed that the CO 2 flue gas concentration increased from 1.8 mol% to 9.6 mol% and 1.5 mol% to 11.6 mol% at 100 kWe and 60 kWe respectively, which improved the performance of the integrated capture plant, indicating that S-EGR operation in the MGT could reduce the specific reboiler duty by 15% whilst increasing the liquid-gas ratio, at a constant capture rate of 90%, thus, reducing overall energy costs. The CCGT study entailed the modelling of fuel flexibility via increasing the CO 2 content in the fuel from a conventional natural gas composition with 1 mol% CO 2 to a maximum CO 2 content of 10 mol%. Then, an Exhaust Gas Recirculation (EGR) study, involving a 35% EGR ratio stream from the exhaust to the compressor inlet, in which the CO 2 content in both the fuel and the air were increased. In both studies, the CCGT is integrated to a capture plant, to reduce the emissions from the power plant. The results indicate that implementing EGR in a CCGT provides better working conditions for the integrated capture plant, when operating with various fuel compositions. The COE and COA associated with EGR implemented CCGT's are noticeably lower and thus proving its high energy savings and emission reductions.

Large hydrate reservoirs in the Arctic regions could provide great potentials for recovery of methane and geological storage of CO2. In this study, injection of flue gas into permafrost gas hydrates reservoirs has been studied in order to evaluate its use in energy recovery and CO2 sequestration based on the premise that it could significantly lower costs relative to other technologies available today. We have carried out a series of real-time scale experiments under realistic conditions at temperatures between 261.2 and 284.2 K and at optimum pressures defined in our previous work, in order to characterize the kinetics of the process and evaluate efficiency. Results show that the kinetics of methane release from methane hydrate and CO2 extracted from flue gas strongly depend on hydrate reservoir temperatures. The experiment at 261.2 K yielded a capture of 81.9% CO2 present in the injected flue gas, and an increase in the CH4 concentration in the gas phase up to 60.7 mol%, 93.3 mol%...

The climate system is changing globally, and there is substantial evidence that subsea permafrost and gas hydrate reservoirs are melting in high-latitude regions of the Earth, resulting in large volumes of CO2 (from organic carbon deposits) and CH4 (from gas hydrate reserves) venting into the atmosphere. Here, we propose the formation of flue gas hydrates in permafrost regions and marine sediments for both the geological storage of CO2 and the secondary sealing of CH4/CO2 release in one simple process, which could greatly reduce the cost of CO2 capture and storage (CCS). The kinetics of flue gas hydrate formation inside frozen and unfrozen sediments were investigated under realistic conditions using a highly accurate method and a well-characterized system. The results are detailed over a wide range of temperatures and different pressures at in situ time scales. It has been found that more than 92 mol% of the CO2 present in the injected flue gas could be captured under certain conditions. The effect of different relevant parameters on the kinetics of hydrate formation has been discussed, and compelling evidence for crystal-structure changes at high pressures has been observed. It has also been found that temperature rise leads to the release of N2 first, with the retention of CO2 in hydrates, which provides a secondary safety factor for stored CO2 in the event of a sudden temperature increase.

Capturing CO2 from power plant flue gas through hydrate formation is starting to be applied on an industrial scale. Several methods have been developed and a large number of experiments have been conducted in order to investigate ways of increasing their efficiency. However, most of them suffer from a lack of detailed kinetic studies. In this paper we present a highly accurate method to investigate the kinetics of flue gas hydrate formation. Preliminary results are detailed at three different temperatures. It has been found that more than 40% of CO2 capture in the form of hydrates occurs after reaching the final pressure. Therefore, statistically constant pressure cannot be used as a sign of thermodynamic equilibrium. The results obtained from this study are important for optimizing CO2 separation operations thus maximizing efficiency and reducing economic barriers. In addition, they are also useful in studying the kinetics of hydrate formation in other gas mixture systems.

Over the past few decades, development of innovative techniques for carbon capture and storage 13 (CCS) from power plant flue gas has become imperative due to substantial increase in the global 14 atmospheric concentration of greenhouse gases, particularly anthropogenic CO 2 . In this regard, it is of 15 utmost importance to have accurate thermodynamic experimental data along with reliable predictive 16 models to be used in the novel CCS techniques such as hydrate-based geological storage methods. In 17 this study, we introduced a new approach to accurately measure the solubility of three different types 18 of simulated power plant flue gases, including coal-fired flue gas, gas-fired flue gas, and syngas, in

Flue gas injection into methane hydrate-bearing sediments was experimentally investigated to explore the potential both for methane recovery from gas hydrate reservoirs and for direct capture and sequestration of carbon dioxide from flue gas as carbon dioxide hydrate. A simulated flue gas from coal-fired power plants composed of 14.6 mole% carbon dioxide and 85.4 mole% nitrogen was injected into a silica sand pack containing different saturations of methane hydrate. The experiments were conducted at typical gas hydrate reservoir conditions from 273.3 to 284.2 K and from 4.2 to 13.8 MPa. Results of the experiments show that injection of the flue gas leads to significant dissociation of the methane hydrate by shifting the methane hydrate stability zone, resulting in around 50 mole% methane in the vapour phase at the experimental conditions. Further depressurisation of the system to pressures well above the methane hydrate dissociation pressure generated methane-rich gas mixtures with up to 80 mole% methane. Meanwhile, carbon dioxide hydrate and carbon dioxide -mixed hydrates were formed while the methane hydrate was dissociating. Up to 70% of the carbon dioxide in the flue gas was converted into hydrates and retained in the silica sand pack.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Waste treatment using thermal arc plasma is well established and laboratory/pilot scale plasma reactors were developed and their performances for the destruction of different hazardous wastes, other than petroleum oily sludge, were studied. This work aims to extend the plasma technology to the pyrolysis of hazardous petroleum oily sludge. A 4.7 kW thermal arc plasma reactor was developed using a standard TIG arc welding torch. The transferred arc plasma reactor was used to treat 20 g/batch of petroleum oily sludge. The prevailing temperature inside the reactor ranges between 356 – 1694 oC. The plasma arc temperature increased with increasing plasma arc current and also with increasing plasma gas flow-rate. A vitreous slag and a flue gas were generated as products. A mass reduction of between 36.87 – 91.40% and a TOC reduction of 21.47 – 93.76% were achieved in the treatment time of 2 – 5 min. The mass reduction was observed to increase with treatment time. However, the increase was ...

Fluor has designed a large-scale carbon dioxide recovery demonstration plant using the Econamine FG Plus SM technology to recover 90% of the CO 2 fro Electric Generating Station. When in operation, the plant will produce 4,776 metric tonnes per day of supercritical carbon dioxide, which will be available for sequestration via enhanced oil recovery. The CO 2 capture plant design includes technology advancements that are expected to lower energy demands, reduce costs, and improve the environmental impact of CO 2 capture. The paper summarizes the technological advancements and expected performance of the capture unit.

Flue gas purification experiments were performed with a membrane made from the ultrapermeable polymer of intrinsic microporosity (PIM) based on tetramethyltetrahydronaphthalene unit coupled with bicyclic triptycene (PIM-TMN-Trip). Permeation experiments with a CO2-N2-O2-SO2 mixture, simulating flue gas from power plants, were performed by means of an in-house developed permeation unit. The results showed very high permeability of the membrane for sulfur dioxide SO2 and high permeability of CO2, lying mainly between the Robeson upper bound form 2008 and the recently reported upper bound from 2019. Moderately high mixed gas selectivity of SO2 and CO2 with respect to N2 (21-29 and 11-18, respectively), in combination with very high permeability (28•10 3 and 30•10 3 Barrer, respetively), suggest potential use for industrial gas separation processes. The SO2/CO2 mixed gas selectivity was relatively low (around 1.8), but comparable with other novel membranes, and both are removed simultaneously in the process of CO2 separation.

This study focuses on improving the efficiency of flue gas purification systems for carbon dioxide (CO2) capture. The researchers investigated various factors, including flow rates, absorbent concentrations, nanoparticles, and temperature, to optimize the CO2 capture process. They conducted experiments using a polytetrafluoroethylene (PTFE) hollow fiber membrane contactor to separate CO2 from nitrogen. The presence of titanium dioxide and silica nanoparticles in a potassium carbonate solution facilitated the separation process. The findings indicate that optimizing flow rates and absorbent concentrations can enhance CO2 capture efficiency. The use of nanoparticles in the absorbent solution was found to improve material capture effectiveness. The study also revealed that higher temperatures contribute to increased CO2 capture efficiency. The research aims to advance CO2 capture techniques to mitigate the release of industrial greenhouse gases, particularly in flue gas treatment syste...

Summary The Medicine Pole Hills Unit (MPHU) EOR project is the deepest air-injection/in-situ-combustion project in the Williston basin. A unit comprising 9,600 acres with 13 producing wells was formed in July 1985, and air-injection operations began in Oct. 1987. Laboratory combustion tests and detailed feasibility studies were completed before starting the full scale project. The combination of light oil (39°API), carbonate formation, hot reservoir (230°F), and low permeability (1 to 30 md) makes this a unique air-injection project. Cumulative air injection as of Dec. 1993 was 12 Bscf. This paper reviews production performance of the MPHU to date. Oil production from the unit has shown a significant increase over its historical decline, and a processing plant has been installed to recover the liquids stripped from the oil by the produced flue gas. Although well workovers, acid fracturing, and pump changes in some producers complicate the determination of the oil response to air inj...

The oxygen content of the gas-fired boiler flue gas is used to monitor boiler combustion efficiency. Conventionally, this oxygen content is measured using an oxygen content sensor. However, because it operates in extreme conditions, this oxygen sensor tends to have the disadvantage of high maintenance costs. In addition, the absence of other sensors as an element of redundancy and when there is damage to the sensor causes manual handling by workers. It is dangerous for these workers, considering environmental conditions with high-risk hazards. We propose an artificial neural network (ANN) and random forest-based soft sensor to predict the oxygen content to overcome the problems. The prediction is made by utilizing measured data on the power plant’s boiler, consisting of 19 process variables from a distributed control system. The research has proved that the proposed soft sensor successfully predicts the oxygen content. Research using random forest shows better performance results th...