Ash Accumulation Research Articles

Modelling and simulation of ash accumulation in SP boiler of decomposition kiln

Modelling and simulation of ash accumulation in SP boiler of decomposition kiln

Modelling and simulation of ash accumulation in SP boiler of decomposition kiln

Modelling and simulation of ash accumulation in SP boiler of decomposition kiln

Оценка содержания биологически активных веществ и химических элементов в листьях хостиириса гибридного в зеленых насаждениях Новосибирской области

The article for the first time presents the comparative results of the content of ash substances, sulfur, phenolic compounds (tannins), ascorbic acid in the leaves of plants Iris hybrida, Hosta decorata, H. albomarginata, H. lancifolia, cultivated in the Central Siberian Botanical Garden (CSBS, Akademgorodok) and used in landscaping the urban environment of the Berdsk and Koltsovo settlements (Novosibirsk region) during the seasonal development in 2020. The specificity of distribution of sulfur, ash, tannins, ascorbic acid in leaves of the studied species was revealed. The quantitative content of the presented groups of substances in the leaves during the flowering period of these objects of study has been determined. Under the conditions of urban environment, an increase in the content of ash substances in the leaves of I. hybrida by 2,5–3,6 times and H. albomarginata, H. lancifolia, and H. decorata by 1,4–1,7 times was found. The general tendency of the accumulation of sulfur and ash in leaves of the species of the genus Hosta, with the greatest value in H. albomarginata growing in green areas of Berdsk was noted. Under the same conditions, the concentration of sulfur in the leaves of I. hybrida increased 1,3 fold compared with Hosta decorata. The content of ascorbic acid and tannins in the leaves of H. albomarginata, H. lancifolia, H. decorata, I. hybrida is 1,1–2,4 times lower in the urban environment of Berdsk and Koltsovo than in plants grown in conditions with a favorable environmental situation (CSBS). In terms of biochemical, habitual, and rhythmological evaluation of the indicators, the species present a comparative series in descending values: H. lancifolia > H. albomarginata > H. decorata > I. hybrida.

Preparation, biocontrol activity and growth promotion of biofertilizer containing Streptomyces aureoverticillatus HN6.

Nowadays, due to the excessive dependence on chemical fertilizers and pesticides in agricultural production, many problems, such as soil hardening and soil-borne diseases, have become increasingly prominent, which seriously restrict the sustainable development of agriculture. The application of microbial fertilizer prepared by biocontrol microorganisms can not only improve soil structure and increase fertility but also have the function of controlling diseases. Streptomyces aureoverticillatus HN6 has obvious disease prevention and growth promotive effect, which can improve the rhizosphere fertility of plants and even regulate the rhizosphere microbial community of plants. Based on the comparison of frame composting and natural composting, we used the response surface method to optimize the preparation conditions of Streptomyces HN6 bacterial fertilizer. The results showed that natural composting not only produced higher composting temperatures and maintained long high temperature periods in accordance with local conditions, but was also more suitable for composting in the field according to local conditions. Therefore, the substrate's conductivity changed more, the ash accumulation increased, and the substrate decomposed more thoroughly. Thus, this composting method is highly recommended. Additionally, Streptomyces HN6 microbial fertilizer EC20 can reduce cowpea fusarium wilt and promote cowpea growth. The number of plant leaves, plant height and fresh weight, increased significantly in the microbial fertilizer EC20. Moreover, Streptomyces HN6 fertilizer EC20 could significantly induce soil invertase, urease and catalase activities. Our study highlights the potential use of Streptomyces HN6 as a biofertilizer to improve plant productivity and biological control of plant pathogenic fungi.

An Efficient Ash Cleaning Method for Flat Box Cartridge Filter: Structure, Parameters and Cleaning Mechanism of Slotted Blowing

The problem of serious ash accumulation at the lower part of flat box filter cartridges is an important limitation for the improvement of ash cleaning efficiency in this kind of filter. To solve the above-mentioned problem, the type of slotted blowing hole impacting the performance of the ash removing under the same ash cleaning area was studied. In the present work, a total of four types of slotted blowing holes with different length were designed. The influence of blowing distance and blowing pressure on dust removal performance were investigated. Numerical simulation was conducted to demonstrate the mechanism of the dust removal process. An industrial coating test was also carried out to investigate and verify the actual ash cleaning performance under the optimal conditions as obtained from the above investigations. The results showed that: (1) the performance of dust cleaning produced by a three-slit blowhole was better than that by a four-slit blowhole; (2) 0.2 MPa was determined to be the optimal blowing pressure, which meets the requirement of ash cleaning; (3) 20 mm was selected as the optimal blowing distance, as this was the distance at which the surface side wall pressure at the non-positive-to-blow hole area was obviously increased, indicating that the whole performance of ash cleaning could be improved. The results obtained in this study are of great significance for improving the efficiency of dust removal in the use of flat box filters, promoting the development of dust removal technology, protection of environment, and reduction of human health damage.

Calculation and Analysis of Heat Transfer Characteristics of Internal Threaded Tube at High Reynolds Number

In the actual operation of a heat storage steam boiler heat exchanger, an internal threaded tube is used as a heat exchange element. Usually, the heat exchanger volume is large and there are many consumables because of the complex composition of flue gas in the pipe so the internal threaded tube in the actual long operation process will suffer from ash accumulation and serious wear phenomenon. In this paper, the heat transfer process of internally threaded tubes is taken as the main research object, and the convection-enhanced heat transfer of internally threaded tubes at a high Reynolds number is deeply studied. For gas under the condition of high Reynolds number, the strengthening of turbulent flow inside of inner grooved tubes convective heat transfer process of deduction and analysis is derived. A fluid calculation model which is more in line with the heat transfer mechanism of threaded pipe is proposed, which provides a reference for the subsequent theoretical studies of heat transfer enhancement of threaded pipe.

Fouling and Slagging Investigation on Ash Derived from Sasol Coal Using ICP and XRF Analytical Techniques

During coal combustion in boilers, light fly ash particles are carried away along with the hot flue gases and the heavier bottom ash particles fall to the bottom of the boiler. The fly ash particles stick on the convective heat transfer surfaces and the furnace wall, causing fouling and slagging deposition problems during the boiler operation. The fouling and slagging effect reduces the boiler’s operational efficiency. This study was motivated by the decline in the operational efficiency of the installed boilers at Sasol synfuel operations in Secunda, Mpumalanga province in the Republic of South Africa. It was assumed that the drop in the boiler efficiency was caused by the coal ash deposition during the boiler operations. The rate of ash deposition and accumulation in the convective heat transfer tubes and furnace water walls during the boiler operation depends on the chemical composition of the coal ash produced during combustion. Coal fly and bottom ash samples were collected from the operational site for laboratory analysis to determine their chemical composition using induced coupled plasma optical emission spectroscopy, induced coupled plasma mass spectroscopy (ICP-OES, ICP-MS) and X-ray fluorescence (XRF) analytical methods. The major, minor and trace elements by mass (%) in the ash samples were obtained from the ICP-OES and ICP-MS, whereas the elemental composition in an oxidised atmosphere was obtained from the XRF analysis. The amount of unburnt coal particles within the ash samples was determined from the loss on ignition (LOI) test. The fouling and slagging prediction during Sasol boiler operation was evaluated using previously developed fouling and slagging indices as a guide using the analysed ash chemical composition results obtained in this study. It was concluded from the analysed results using the guided evaluated indices from the analysed coal ash chemistry that during the operations of Sasol boiler(s) there is a low to medium fouling prediction occurrence on the convective heat transfer tubes and a low slagging in the boiler furnace walls.

Combustion features and use of space. A micromorphological approach to the Neolithic occupation at Cova de les Pixarelles (Barcelona, Spain)

Combustion structures are a key element in archaeology for understanding the articulation of the social spaces of past societies since they allow us to approach domestic activities, given their role in daily life production and consumption practices. In the last years, the study of hearths and other combustion features has been enriched by applying a set of new methodologies, which has made it possible to delve deeper into its study and know both the activities involved in its use and the management.In this article, we present the results of a micromorphological study carried out at the Cova de les Pixarelles site (Tavertet, Barcelona). The aim is to contribute to the knowledge of the use of space and rhythms of occupation of the Middle Neolithic societies in the northeast of the Iberian Peninsula by studying combustion structures and their management. The exceptional conservation of the remains in strata of highly organic composition due to the formation of travertine layers in the periods when the cave is not occupied constitutes this cave as a benchmark for occupations in karst cavities during recent prehistory in the region. More specifically, we will focus on Level XXII, consisting of a thick accumulation of ashes and faunal remains, among other utilitarian elements. Therefore, the ethnographic vision of the use of the cavity in the economic and social cycle is deepened by the first results of the micromorphological analysis and the rest of the archaeological record, which points to an intense occupation with several episodes of use related to several combustion features and changes in space management with possible specific purposes.

A study of the early life of gasoline particulate filters: Reactive and dissipative acoustic effects

The presence of after-treatment systems (ATS) has some side effects as they modify the wave dynamics, back-pressure and acoustic behavior of the exhaust system, that define the boundary conditions for the main silencing device. Gasoline particulate filters (GPF) have a considerable influence on these traits as their working principle depends on wall-flow monoliths; additionally, particulate filters have an inherent transient behavior due to the loading-regeneration cycles during their operation. In this paper, the steady and unsteady behavior of a typical device containing a three-way catalyst (TWC) and a GPF has been characterized in "new" (prior to any use) and "used" (after regeneration) conditions, with special focus on the role of dissipation. Pressure drop measurements were used in steady flow, whereas an acoustic energy balance was performed in the unsteady case that allows for the identification of the reactive and dissipative contributions. The results obtained for the GPF suggest that after it has been used for a relatively short time it oscillates between a maximum and a minimum loading over load–regeneration cycles burning the soot, never reaching back brand–new cleanness due to accumulation into the substrate pores and only suffering from ash accumulation over very long times. The results were then used to analyze the ability of a standard gas-dynamic code to reproduce the influence of the loading on the reactive and dissipative effects observed, with the main conclusion that by properly tuning the model parameters it is possible to reproduce, at least qualitatively, the trends observed in the experiments. The model can thus be used to provide adequate inlet conditions for the design of the exhaust line.

Optimization of coal fly ash-based porous geopolymer synthesis and application for zinc removal from water

Coal fly ash-based porous geopolymer (CFAPG) is a potential adsorbent for heavy metal-contaminated water remediation and can also mitigate the accumulation of coal fly ash from thermal power plants. Production parameters influence the physicochemical properties (e.g., adsorption capacity) of CFAPG. Ten potential factors involved in the CFAPG production process were examined using a Plackett-Burman design (PBD) and then an orthogonal experimental design (OED). The results show the alkali activator modulus (MS), alkali-ash mass ratio (AA), foaming agent-ash mass ratio (FAR), and sodium dodecyl sulfate-ash mass ratio (SDSA) were the most important factors influencing the Zn adsorption capacity of CFAPG. Ternary plots confirm the interaction between these four factors, with the role of FAR being easily masked by other factors and MS being the least influenced by other factors. Furthermore, Zn adsorption on the CFAPG created with optimal parameters was best described by the Bi_Langmuir model, indicating two different sorption site classes on the surface of CFAPG with a total maximum Zn adsorption capacity of 13.42 mg g−1. These results provide key parameters for the production of geopolymers as heavy metal adsorbents.

Utilization of Silica Fume and Fly ash in Cement and Partial Substitution of Fine Aggregate Using Quarry Dust in Concrete

Thecemententerprisebetheessentialhotspotintendedfornaturalcontamination because it admissions a tremendous measure of energy during the creationas well as deliveries a ton of CO2which adds to an unnatural weather change. Reducethese impacts, concrete is to some degree subbed among the blend of Silica Fume (SF) and Fly Ash (FA) and sand by Quarry Dust (QD) with addition of steel fibre. This paper is centered on theconduct of substantial blend of M30 grade with particular of mechanical properties. Various mixes of rate substitutions of concrete by SF (5%) and FA (5%, 10%, 15%, 20%, 25%) and quarry dust (5%, 10%, 15%, 20%, 25%) with addition of steel fibre (1 %) were embraced for the making of mixed substantial blend. Test results indicated to facilitate the accumulation of silica fume and fly ash in cement and quarry dust in sand improved the compressive strengths of concrete.

Formation of calcium chloride brines in volcaniclastic-rich sediments

The Amami-Sankaku Basin, located in the Philippine Sea, records approximately 50 million years of sediment accumulation and diagenesis of volcanic ash derived from the Kyushu-Palau and Kyushu-Ryukyu arcs. Analyses of porewater and sediment samples from the 1461-m core recovered at IODP Expedition 351, Site U1438, included major and trace elements, strontium radiogenic isotope ratio (87Sr/86Sr), and taxonomic identification of archaeal classes and bacterial orders. Sediment X-ray diffraction and thin section analyses show that smectite, zeolites and chlorite are the main authigenic minerals. A multicomponent solute diffusion and reaction numerical model was developed to simulate the long-term diagenesis that took place in this sedimentary sequence and to account for the transition to a calcium chloride brine at about 670 mbsf. Numerical results indicate that 45% of the initial amount of volcanic ash has been dissolved at 750 mbsf. At this depth, 13% of the initial water (H2O) in the pore space is estimated to have been transferred to the solid phase by the formation of zeolites, which accounts for an increase in porewater chloride concentration. In contrast, dissolution of anorthite and volcanic ash combined with sodium uptake by zeolites accounts for the predominance of calcium in the brine. In the upper 160 m of the sedimentary column, the electrochemical migration of solutes causes chloride to move in the opposite direction of the concentration gradient, i.e., uphill diffusion, sustaining downward diffusion of seawater chloride into the sediments.

High-resolution sediment analysis reveals Middle Bronze Age byre-houses at the site of Oppeano (Verona province, NE Italy).

High-resolution sediment analysis allowed us to identify two Middle Bronze Age (MBA 1, 1650–1550 cal a BCE) byre-houses at the waterlogged site of Oppeano “4D”, south of Verona (Veneto region, NE Italy). The site lies in a low-lying valley incised by the Adige River in its LGM alluvial fan. In this fluvio-palustrine environment burial and taphonomic conditions were such that the archaeological record was extremely well preserved. The wooden elements making up basal parts of nine ‘huts’ were in fact exposed at Oppeano, and so were their internal accretion deposits. These featured finely laminated dung units deriving from the stalling of small herbivores, possibly ovicaprids, intercalated with repeated accumulations of wood ash. This was produced in large and multi-stratified hearths that were exposed within each hut. Organic petrology provided evidence of the production of wood tar inside one of the studied structures. At Oppeano 4D it was thus demonstrated that these structures were not just byres or stables, but spaces that housed humans together with animals at least during some periods of the year, hence byre-houses. The identification of byre-houses in a Middle Bronze Age settlement is key for the reconstruction of socio-economic aspects of Bronze Age economy and production systems.

Deep Learning-Based Approach for Heat Transfer Efficiency Prediction with Deep Feature Extraction.

Failure to blow ash on the heated surface of the boiler will cause a drop in heat transfer rate and even industrial safety accidents. Nowadays, the shortcomings of the fixed soot blowing operation every hour and every shift are significant, which can be improved by high-precision ash accumulation prediction. Therefore, this paper proposes a deep learning model fused with deep feature extraction. First, a dynamic fouling model and a health index-clearness factor (CF) of the heated surface are established. The data preprocessing method reduces unnecessary forecasting difficulty and makes the degradation trend of the CF time series more obvious. In addition, deep feature extraction is composed of complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and kernel principal component analysis (KPCA), which completes the multiscale analysis of time series and reduces the training time of deep learning models, and has significant contributions to improving prediction accuracy and reducing time consumption. The adaptive sliding window and the encoder–decoder based on the attention mechanism (EDA) can better mine the internal information of the time series. Compared with long short-term memory (LSTM), taking the 300 MW boiler’s various heated surface data sets as an example, multistep forward prediction and different starting point prediction experiments have verified the superiority and effectiveness of the model. Finally, under the variable working condition economizer datasets, the proposed method better completes the predictive maintenance task of the heated surface. The research results provide operational guidance for improving heat transfer rate, energy saving, and reducing consumption.

An experimental and modeling study of ash deposition and migration in diesel particulate filters

Ash accumulation in wall-flow filters impacts key performance aspects such as pressure drop, filtration efficiency and catalytic reactivity. In this context, the capability to predict ash deposition and transport behavior is essential to ensure proper system performance under various operating conditions, throughout the useful lifetime of the particulate filter. Despite a large number of previous experimental studies, physically based ash migration models to predict ash transport and its impact on the performance of a wall-flow filter are still not available. The development, calibration and validation of a phenomenological semi-predictive model is presented in this work, based on extensive burner rig and transient engine tests. Combustion-derived ash was collected in several bare DPFs, while the filters’ pressure drop was monitored and the plug ash length was estimated via borescope and CT-scan tests. An example of how the developed model can be used to study design variations at an early development phase is included.

Сравнительный анализ кормовой ценности сортов суданской травы в условиях Карагандинской области

The article presents the results of an experiment on the cultivation of three varieties of Sudanese grass in the conditions of Karaganda city. Sudanese grass is a heat-loving valuable food crop with high drought resistance. It is cultivated to produce green feed, hay, silage. It is a rich source of vitamins, proteins, minerals. The results of field experiments showed that cryopreservation of Sudanese grass seeds had a positive effect on the productivity of the aboveground mass. Excess in terms of yield indicators for the “Novosibirsk 84” variety is 38.85 c/ha for raw weight and 58.80 c/ha for dry weight; for the “Nika” variety — by 23.55 and 41.25 c/ha, respectively; for the “Tugai” variety — 8.55 and 8.55 c/ha, respectively. According to the fodder value analysis, all three varieties of Sudanese grass have good nutrition of aboveground organs. Varieties differ slightly in the accumulation of starch, sugar, raw protein, ash, carotene, calcium, and phosphorus. Preliminary data make it possible to distinguish the “Novosibirsk 84” variety with the maximum yield, and the “Tugai” variety with the maximum accumulation of elements of fodder value.

A Hybrid Method for Prediction of Ash Fouling on Heat Transfer Surfaces

Soot blowing optimization is a key, but challenging question in the health management of coal-fired power plant boiler. The monitoring and prediction of ash fouling for heat transfer surfaces is an important way to solve this problem. This study provides a hybrid data-driven model based on advanced machine-learning techniques for ash fouling prediction. First, the cleanliness factor is utilized to represent the level of ash fouling, which is the original data from the distributed control system. The wavelet threshold denoising algorithm is employed as the data preprocessing approach. Based on the empirical mode decomposition (EMD), the denoised cleanliness factor data is decoupled into a series of intrinsic mode functions (IMFs) and a residual component. Second, the support vector regression (SVR) model is used to fit the residual, and the Gaussian process regression (GPR) model is applied to estimate the IMFs. The cleanliness factor data of ash accumulation on the heat transfer surface of diverse devices are deployed to appraise the performance of the proposed SVR + GPR model in comparison with the sole SVR, sole GPR, SVR + EDM and GPR + EDM models. The illustrative results prove that the hybrid SVR + GPR model is superior to other models and can obtain satisfactory effects both in one-step- and the multistep-ahead cleanliness factor predictions.

Nutritional value and consumer perception of biofortified sweet potato varieties

The deficiency of vitamin A is associated with preventable childhood infections and blindness. Optimal nutrition from a dietary variety and a selection of nutrient-rich foods are needed to enrich the diet. Orange-fleshed sweet potato (OFSP) is a source of provitamin A due to its bioavailability of carotenes in roots that can be influenced by variety, environmental and crop management conditions. The aim was to characterize six of sweet potato genotypes [yellow-fleshed sweet potato (YFSP) and OFSP] using high-throughput phenotyping approaches to determine the influence of multi-environmental evaluation on quality attributes. The sensory evaluation was included to recognize the consumer perception of biofortified varieties. Total carotenoids content (TCC) and all-trans-β-carotene (atβC) were determined via HPLC, and colorimetric measurements were used to evaluate the root flesh color. Sensory evaluation was done for two OFSP and the cream-fleshed (CFSP) traditional landrace. Results revealed that the nutritional richness of OFSP was exhibited in its high TCC and atβC. High temperature and low accumulated rainfall negatively affected the accumulation of dry matter (DM), ash, and crude fiber while enhancing soluble solids, TCC, and atβC content. The food composition table of Ambarina and Aurora varieties showed the enriched quality compared to that of CFSP traditional landrace. Colorimetric methods were successfully used to differentiate flesh colors that could be significantly related to nutritional quality, especially a* and b* values from colorimeter and red (R), green (G), and blue (B) pixel values. High acceptance of OFSP varieties in sensory attributes suggested the potential of these biofortified varieties as nutrient-rich foods and prevented vitamin A malnutrition.

Dynamic Response of Cement–Fly Ash Mixed Pile Composite Foundation Under Wave Load

CFMPs (cement and fly ash mixing piles) are used to reinforce fly ash foundation to solve the problem of a large amount of fly ash accumulation in coastal areas. CFMP-fly ash composite foundation is used as the foundation of coastal and coastal engineering. Through the indoor model test, the bearing characteristics and load transfer mechanism of CFMP-fly ash composite foundation under wave load were investigated. The results show that with the increase of wave load, the horizontal resistance of the fly ash stratum increases gradually, the soil resistance moves down, and the level of resistance shows nonlinear characteristics. The pile bending moment, pile displacement, and horizontal resistance of the CFMP composite foundation are concentrated in the upper pile and fly ash stratum, which can improve the ability of the composite foundation to resist horizontal load by improving the physical and mechanical properties of the upper fly ash stratum. Through the calculation of the load–displacement curve, it is found that the measured displacement value is closer to that obtained using the p–y curve method (a method for solving nonlinear lateral resistance of piles). The hysteretic curve area of cyclic loading decreases with the increase of cyclic number. The accumulation of elastoplastic deformation of pile shows that the properties of fly ash gradually change to elastic stage, cyclic loading can reduce the horizontal deformation modulus of composite foundation CFMP caused pile—fly ash system of weakening, in peak load reaches level under the critical state displacement curve showed a trend of the rapid growth of nonlinear, cyclic cumulative failure occurs, and the cyclic load limit state is reached, which affects the service performance of the whole structure.

Coal-direct chemical looping hydrogen generation with BaMnO3 perovskite oxygen carrier

Coal-direct chemical looping hydrogen generation (CDCLHG) is a novel process that uses coal to directly produce H2 with inherent CO2 capture. A key issue is to find out suitable oxygen carriers for this process. In this study, perovskite was proposed as the oxygen carrier for CDCLHG, and a series of Mn-based and Fe-based perovskite oxides were synthesized by a sol-gel method for CDCLHG reactions in a fixed-bed reactor. The results showed that BaMnO3 was an optimal oxygen carrier for CDCLHG, which could obtain H2-rich gas (>85%) with a high H2 gas production rate, about 13 times higher than that in char steam gasification. Further tests showed that the optimal reaction temperature and O/C ratio were 850 °C and 1: 0.05, respectively. XRD and XPS patterns indicated that part of the lattice oxygen in BaMnO3 could convert to the carbonate oxygen in BaCO3 during the fuel oxidation stage (FO stage) and obtained BaMnO3-δ with plentiful oxygen vacancies in it. The BaMnO3-δ could partially restore its lattice oxygen in the reduction of steam stage (RS stage) and completely recover its initial structure in the air calcining stage (AC stage). SEM images showed that the decrease of BaMnO3 reaction performance after 9 cycles was mainly due to ash accumulation.