Improving technology for manufacturing casting case of truck clutch release cylinder

The object of research: Manufacturing technology of body castings for trucks using the example of a clutch release cylinder body made of gray cast iron with flake graphite EN-GJL-200. Investigated problem: Finding ways to reduce the weight and size characteristics of cast parts. The main scientific results: A mathematical model has been developed that has made it possible to determine the optimal compositions of alloying Cr/Ni – Cu/Ti complexes that ensure an increase in the grade of cast iron by increasing the tensile strength at elevated carbon contents. This makes it possible in the future to reduce the thickness of the walls of the castings, achieving a reduction in their weight and size characteristics The area of practical use of the results of the study: Automotive industry in terms of technology for manufacturing cast parts for trucks Innovative technological product: Improved technology for manufacturing the clutch release cylinder body due to optimization of melt technology and out-of-furnace processing allows for targeted selection of melt processing modes, ensuring an increase in the strength characteristics of cast iron for cast body parts, thereby moving from the EN-GJL-200 cast iron grade to the EN grade -GJL-250 and EN-GJL-300. The scope of the innovative technological product: Foundries of engineering enterprises, in particular those producing trucks, in which iron castings are produce

Exploiting the potential of chemical looping processes for industrial decarbonization and waste to energy conversion. Process design and experimental evaluations

The impact of anthropogenic activities on the environment is leading to climate changes and exceptional meteorological phenomena all over the world. To address this negative trend, the scientific community agrees that the environmental impact from fossil fuels-based power production must be mitigated by the integration with alternative and sustainable technologies, such as renewable energy. However, the time required for the complete development and diffusion of such technology poses the urgency of finding a midterm solution to significantly reduce CO2 emissions. Carbon capture, utilization, and storage (CCUS) technologies represent an interesting option to mitigate CO2 emissions. CCUS involves (among other possible applications) the separation of the CO2 content from industrial off-gases, its transport and storage or its reconversion to a chemical/fuel. Chemical looping can be considered as an oxyfuel combustion where the oxygen supply comes from the lattice oxygen atoms of a solid. It is based on gas-solid reactions where a solid also known as oxygen carrier, generally a metal oxide, undergoes successive reduction and oxidation steps. In the reduction step, normally occurring at high temperatures (700-1000 °C), the oxygen carrier interacts with a reducing agent, such as coal, natural gas, syngas etc. and loses part of its oxygen atoms. By controlling the degree of reduction of the oxygen carrier is thus possible to achieve a complete oxidation of the reducing agent (the fuel) to CO2 and H2O (chemical looping combustion) or a partial oxidation to a syngas (chemical looping reforming and gasification). In these latter case, the introduction of external CO2 and H2O can be of help to support the reforming or gasification processes. The oxygen carrier in the reduced phase is then sent to an air reactor, where it reacquires the oxygen atoms by an exothermic reaction with air. This process presents several advantages according to the specific application. In chemical looping combustion, intrinsic separation of N2 and CO2 is achieved, because the two streams are involved in two different reaction steps. This largely simplifies the CO2 separation effort for storage or utilization purposes. On the other hand, in chemical looping reforming it is possible to achieve autothermal operation thanks to the exothermicity of the oxidation step in the air reactor, as well as high reforming efficiencies. Similarly, in chemical looping gasification the resulting syngas is characterized by no N2 dilution, lower tar release and possibility of autothermal operation. These benefits enhance the energy efficiency of the process, leading to a better energy utilisation. In this work, strategies for the decarbonisation and circularity of the industrial and power sector are proposed based on the synthesis of hydrogen and hydrogen-derived fuels. In particular, the potential of chemical looping technology is deeply studied aiming at exploiting its ability to reconvert or valorise CO2 or waste streams to a syngas and then to a liquid fuel/chemical, such as methanol or ammonia. This task is carried out through modelling and experimental evaluations. The modelling activities mainly concern design of process schemes involving the chemical looping section for waste or CO2 reconversion and the liquid fuel synthesis section. The experimental evaluations are focused on two crucial that have been limitedly discussed in the literature: the thermochemical syngas production step by oxidation with CO2 and H2O streams, the effect of high-pressure operation on the redox abilities of a typical iron and nickel-based oxygen carrier. In Chapter 1, a general overview on the main research developments on chemical looping technology is provided. A section is reserved for each chemical looping variant, i.e. combustion, reforming and gasification, and a general description of each process is provided along with the summary of the main research achievements. Subsequently, the technology is divided by application in power production and chemicals production. Main findings from techno-economic assessment and process designs are discussed in comparison with benchmark technologies and other clean pathways. In Chapter 2 steel mills are taken as an example of the hard-to-abate industry. A H2-based decarbonization strategy is proposed and assessed by Aspen Plus simulation. The strategy starts from an initial configuration that is characterized by a typical blast furnace-basic oxygen furnace steel mill and consider the introduction of direct reduction – electric arc furnace lines, that are more efficient and involve natural gas as reducing agent rather than coke. Sensitivity analyses are carried out to assess the effect of the introduction of H2/CH4 blendings in the direct reduction plant and of the utilization of scrap material in the electric arc furnace. The impact of each configuration on the CO2 emissions and the energy flows of the plant is assessed by mass and energy balances. The results indicate a promising decarbonization potential of the introduced technologies but require large investments to increase the renewable sources penetration in the energy mix and large availability of H2. Therefore, alternative pathways for an earlier decarbonization of hard-to-abate industries and for large scale syngas/H2 production need to be considered. In Chapter 3, a novel process scheme is proposed involving chemical looping for syngas production. The CO2 content in blast furnace gases is separated with a calcium looping cycle and subsequently injected with H2O into the oxidation reactor of a chemical looping cycle. Assuming an inlet stream of pure CO2, mass balances on the chemical looping plant are carried out to compare the performance of nickel ferrites and iron oxides in terms of required oxygen carrier flow rate to process 1 t/h of CO2. Computational fluid dynamics simulations with integrated reaction kinetics are then carried out to validate the assumptions on the oxygen carrier conversion and syngas compositions. In Chapter 4 and 5, experimental evaluations are carried out on two crucial aspects for the successful operation of a chemical looping plant aiming at syngas production. In Chapter 4, the syngas productivity by CO2 and H2O splitting over a Fe bed is investigated. This is a very important step, and the effect of various parameters was considered. Firstly, the CO2 splitting is analysed for different temperatures with an inlet flow rate of 1 NL/min to ensure a substantial dissociation of the CO2. Subsequently, combined streams of CO2 and H2O are evolved in the reactor. The effect of the total flow rate, reactants molar ratio and bed height is investigated and from the results, the optimal syngas composition is identified. SEM and XRD are used to assess the morphological evolution and the phase changes of the material during the test. On the contrary, in Chapter 5 the effect of high-pressure operation on the redox abilities of two NiFe aluminates is assessed. The aluminates present similar Fe loadings, but different Ni loadings. High pressure operation is crucial for the development of this technology because it facilitates downstream processing of the syngas to liquid fuels. For a comparative analysis, preliminary tests at low pressure are carried out at three temperatures. Subsequently, the effect of reactants flow rate, temperature, total pressure, gas composition is analysed at high pressure conditions. Finally, long term tests are performed both at ambient and high-pressure conditions. Material characterization by SEM, XRD and H2-TPR is used to support the comparative analysis. In Chapter 6, a techno-economic analysis on a process scheme encompassing methanol and ammonia production from chemical looping gases is carried out. Chemical looping hydrogen production is a very versatile technology and allows for the combined production of power and H2 or syngas. With proper calibration of the flow rates, a stream of high purity N2 can also be obtained at the air reactor outlet and used for ammonia synthesis. Back up with an alkaline electrolyser is considered for the supply of the required amount of hydrogen. Sensitivity analyses are carried out on the chemical looping plant to evaluate the effect of fuel flow rate, steam flow rate, and oxygen carrier inlet temperature to the fuel reactor. Subsequently, a techno-economic analysis is carried out evaluating several parameters among which: the specific CO2 emissions, the energy intensity, and the levelized cost of methanol and ammonia. Finally, a comparison with benchmark technologies and other clean alternatives is presented. In this way, the benefits as well as the drawbacks of chemical looping in terms of environmental and economic parameters are assessed and the missing elements to reach industrial competitivity are clarified

Study of Two Instrumental Variable Methods for Closed-Loop Multivariable System Identification.

New control strategies are based on the model of the process and it is thus necessary to identify the systems to be controlled. It is also often necessary to identify them during closed-loop operation in order to maintain efficient operation and product quality. Some results of multivariable closed-loop identification carried out on a simulated 2 x 2 linear time-invariant system, using two new versions of instrumental variable methods called IV4D and IV4UP as the identification methods, are presented. In each case pseudorandom binary signals (PRBS), or dithers, are applied to the outputs of the feedback controllers. Algorithms IV4D and IV4UP are created in a four step environment where iterations are performed to obtain the best possible estimated model. For IV4D only the dither is used as part of the instrument. For IV4UP only the part of the input that comes from the dither is used for the instrument. This is obtained with the estimated model and with the description of the controllers using the closed-loop transfer function between the dither and the input to the process. The implementation is made to be run in MatLab and it uses several of the functions defined in its System Identification Toolbox (Ljung, 1991). Both instrumental variable (IV) algorithms perform very well identifying closed-loop multivariable systems under the influence of white noise and correlated noise disturbances. The two new instrumental variable methods are compared with the prediction error method, PEM, and with IV4, the regular instrumental variable open-loop algorithm, both of them are obtained from the MatLab System Identification Toolbox. IV4 does not perform well in closed-loop operation. From the simulated results, the performances of the new IV algorithms are the best but, PEM\u27s performance is very close. Finally, real plant data are analyzed with IV4D and its results are compared with the results of other identification methods, PEM and Dynamic Matrix Identification (DMI) (Cutler and Yocum, 1991). For this closed-loop real plant data PEM is the best that performs followed by IV4D, while DMI does not perform well

THE STRUCTURE AND REACTIVITY OF SOME METALLURGICAL CARBONS

The reactivity and micro-structure of three coals and two cokes used in iron and steel manufacture have been studied by a variety of techniques, including gas sorption analysis, thermal analysis and microscopy. Changes in surface areas and porosities of the coals and cokes during combustion have been determined by a gravimetric nitrogen sorption technique at 77K. The cokes and coals have been studied by thermal analysis under isothermal and dynamic conditions in different gas atmospheres. Rates of reaction have been correlated with surface area changes. Attempts have been made to calculate activation energies from Kissinger plots of DTA data. Microstructural changes in the cokes and coals during carbon burn-off have been investigated by electron microscopy. Relative porosities have been estimated by image analysis. Mechanical strengths of the cokes have been measured and correlated with porosity data. Selected metals in the carbons have been determined by flame photometry, atomic absorption spectroscopy and Mossbauer spectroscopy. The composition of residual mineral matter (ash) has been investigated by X-ray diffraction. The chemical compositions of the coal distillates have been characterised by ir/uv spectrosopy, NMR spectroscopy and by GC-MS techniques. Calorific values of the carbons have been determined. Results are discussed in relation to previous work and to applications 1n blast furnace practice. In coal combustion the surface areas increase during the initial stages of carbon burn-off, reaching maximum at about 50% burn-off before decreasing. The increases are considerably higher at 400° and 500° C than at 300° C for all three coals. Hysteresis data from the sorption isotherms show that the coals develop full ranges of mesa-porosity and some micro-porosity during burn-off at the higher temperatures. However, the coal oxidation is only slightly accelerated, since most of the new surface is located in the micro- and meso- pores where access to atmospheric oxygen is restricted by slow diffusion, so that the earlier stages of oxidation are approximately linear with time. This improves our knowledge of current empirical industrial carbon solution tests. There is comparatively little change in surface during the coking of the Coals at 1000° C and only restricted sintering of the coal ashes at 300- 500° C. In the combustion of the cokes in carbon dioxide at 1000° C the maxima in surface areas occur within 25% burn-off. However, one of the cokes shows a second maximum at later stages of burn-off, ascribed to the European component in the parent coal blend. This gives a more uniform rate of burn-off which is advantageous industrially.British Steel Corporation, Teesside Laboratorie

Electrification of the basic materials industry – Implications for the electricity system

The European energy-intensive basic materials industry must achieve deep reductions in CO2 emissions to meet the targets set out in the Paris Agreement. The rapid decline in the cost of renewable electricity makes expanded electrification an attractive option for eliminating the dependence of the industry on fossil fuels. This work applies techno-economic optimisation modelling to investigate how electrification of the basic material intensive industry in EU can interact with the electricity system. In particular, this work examines the ability of basic material industry to take advantage of flexibility options in the production processes to avoid high-cost electricity and facilitate the integration of wind and solar power. The thesis considers flexibility options which can meet an uneven distribution of electricity in time and space, including options to invest in overcapacity in electrolysers for hydrogen production and storage (flexibility in time) and the ability to export commodities (flexibility in location) for the industries included (ammonia, cement, plastics, and steel). For the electrified process of plastics production, flexibility in terms of CO2 utilisation is used to describe the ability of industrial units to vary their CO2 utilisation modes, i.e., through carbon capture and utilisation and carbon capture and storage.The modelling results show that an energy-intensive basic materials industry that has flexibility in relation to time, location, and CO2 utilisation provides lower production costs compared to a non-flexible industry. This is despite the lower capacity utilisation rate (60%) of the electrolysers used for hydrogen production, i.e., it is cost-efficient with investment in over-capacity in electrolysers. The modelling results also show that availability of low-cost electricity generation is the main determining parameter for geographical location of new industries with high operational flexibility and high hydrogen intensity (in this work presented by ammonia industry). With present-day locations of the industry, a hydrogen pipelines network allows for moving the electrolyser capacity from industry-intensive regions to regions with access to low-cost electricity which reduces hydrogen production costs by 3%. With the modelled optimal geographical location of new industries, hydrogen production is in the same region as the hydrogen-consuming units and, thus, a hydrogen pipeline has no significant impact on the hydrogen production cost.It was found that the electrification of the energy-intensive basic materials industry in the EU increases the electricity demand by around 44% (by 1,200 TWh). The future EU electricity demand with the present-day locations of the industrial plants is primarily met by solar, wind and nuclear power. If changes in annual production volumes and relocation of industries are allowed, more commodities are produced in regions that have both existing industries and access to low-cost electricity, thereby increasing the levels of electricity generation from wind and solar power. All the modelled scenarios require a substantial and rapid increases in renewable electricity capacity

Optimising Carbon Type Differentiation Techniques to Reduce Dust Emissions in Blast Furnace Ironmaking

The manufacturing process of iron, using the blast furnace (BF) generates dust as a by-product, which is recycled, however, the generation of the dust in excess is undesirable. A comprehensive review of the dust has determined that each of the raw materials for blast furnace ironmaking contributes to its formation, including several forms of carbon thus addressing the hypothesis ‘The raw materials that feed the blast furnace are expelled into the gas stream and all influence the blast furnace dust.’ The current technique for quantifying coal originating carbon type mostly in the form of coal char, referred to as the nominal term Low Order Carbon (LOC) within BF dust consists of thermogravimetric analysis (TGA) however, this technique does not allow for samples of dust to be analysed in a timely manner, in line with the ever-changing conditions of the blast furnace. In this work, the TGA method has been trialled for use with BF dust, with improvements offered to the heating profile, allowing for faster analysis. Moreover, alternative techniques have been trialled, in combination with various characterisation methods such as X-ray diffraction, Scanning Electron Microscopy, total carbon and Optical Emission Spectroscopy. The ‘Winkler Method’ which was originally designed to quantify charcoal in soil sediment has been successfully adapted and optimised to suit LOC quantification in BF dust, showing a good correlation with the original benchmark technique. This answered the hypothesis, ‘Thermal techniques can be used to differentiate carbon sources in dust generated in blast furnaces that use granulated coal injection.’ The techniques for LOC quantification were applied to dust samples spanning a 9 month period. to determine the process parameters that influence the LOC presence within the dust. It was found that the resolution of sampling is key to identify relationships between process parameters and LOC within the dust. A novel technique to continuously monitor the dust output of the furnace found that the dust output and the LOC within the dust are related, where the increasing dust output leads to increasing concentrations of LOC within the carbon profile of the dust itself. Process parameters including blast pressure, blast volume, and production rate were considered to increase the dust output from the furnace based on the work of the dust probe, thus answering the hypothesis ‘Coal combustion in the raceway can be impacted by process parameters and the evidence can be found in the fingerprint of blast furnace dust.’ A node mapping exercise was used to model an ideal set of process conditions for low dust operations. The foundations to make macro advances in carbon and dust output reduction in blast furnace ironmaking are laid out in this thesis

The behavior of tellurium during copper ore processing at the American Smelting and Refining Company (Tucson, AZ)

Thesis (M.S.) University of Alaska Fairbanks, 2016Essentially all tellurium (Te), an element used in solar panels and other high technology devices, is recovered as a byproduct of copper mining. Recent increases in demand have sparked questions of long-term supplies of Te (crustal abundance ~3 μg∙kg-1). As part of a larger study investigating Te resources, this project examines the behavior of Te during Cu ore mining, smelting, and refining at the American Smelting and Refining Company (Tucson, AZ) as a first step toward optimizing Te recovery. Mass balance calculations estimate that only 4 ± 1% of the Te in the ore reports to the Cu anodes, while 60 ± 30%, 0.8 ± 0.2% and 5.8 ± 0.4% is lost in the tailings, slag, and dust, respectively. The uncertainties reported are the standard deviation of analytical measurements, but due to heterogeneity of Te distribution in the ore, the actual uncertainty is likely higher. Microprobe data shows that Te in the concentrate is mainly present as telluride minerals, but substitution into sulfides most likely also occurs. X-ray fluorescence (XRF) mapping showed that Te is collocated with S in the raw anode slimes, pressed anode slimes, and doré furnace soda slag. X-ray absorption spectroscopy (XAS) was used to examine Te speciation in anode slimes. It was found that Te oxidizes during the Cu ore smelting process, with 44% Te4+ in the flash furnace SO₂ filter. Te also showed 32% Te4+ in the raw and pressed anode slimes. The doré furnace soda slag and dust filter showed the most oxidation of Te at 57% Te4+ and 60% Te6+ respectively. These results indicate several points in the extraction process that could be examined further to determine if additional Te might be recovered from the overall process.Chapter 1 Introduction -- 1.1. What is Tellurium? -- 1.2. Tellurium End Uses and Market -- 1.3. Global Supply of Tellurium -- 1.4. Tellurium Scarcity and Criticality -- 1.5. Current Copper Extraction Process -- 1.5.1. Copper Mining -- 1.5.2. Copper Smelting -- 1.5.3. Copper Refining -- 1.6. Tellurium Byproduct Recovery -- 1.6.1. Mineralogy of Tellurium in Ore Deposits -- 1.6.2. Behavior of Tellurium during Copper Concentration -- 1.6.3. Behavior and Mineralogy of Tellurium in Copper Anodes and Anode Slimes -- 1.6.4. Extraction of Tellurium as a Copper Byproduct -- 1.7. Research Objectives -- Chapter 2. Site Description -- 2.1. The Mines -- 2.2. The Smelter -- 2.3. The Refinery -- Chapter 3. Methods -- 3.1. Sample and Standard Collection, Preparation, and Preservation -- 3.2. Elemental Analysis -- 3.2.1. Inductively Coupled Plasma Mass Spectrometry -- 3.2.1.1. Method Development of Sodium Peroxide Sinter -- 3.2.1.2. Sample Preparation for ICP-MS -- 3.2.1.3. ICP-MS Elemental Analysis -- 3.2.2. Wavelength Dispersive X-Ray Fluorescence -- 3.2.2.1. Sample Preparation and Analysis of WD-XRF -- 3.3. Mass Balance Calculations -- 3.4. X-Ray Absorption Spectroscopy -- 3.4.1. Bulk S XAS -- 3.4.1.1. Bulk S XAS Collection -- 3.4.1.2. S XAS Data Analysis -- 3.4.1.3. S Linear Combination Fitting -- 3.4.2. Bulk Te XAS -- 3.4.2.1. Bulk Te XAS Collection -- 3.4.2.2. Te XAS Data Analysis -- 3.4.2.3. Te Linear Combination Fitting -- 3.5. Microfocused X-Ray Fluorescence Map Collection and Analysis -- 3.5.1. Experimental Conditions -- 3.5.2. Map Analysis -- 3.6. Electron Microprobe Analysis -- 3.6.1. Experimental Conditions -- Chapter 4. Results -- 4.1. Method Development and Verification -- 4.2. Elemental Analysis of Samples -- 4.3. Mass Balance -- 4.4. X-Ray Absorption Spectroscopy -- 4.4.1. Sulfur -- 4.4.2. Tellurium -- 4.5. Micro-focused X-Ray Maps -- 4.6. Electron Microprobe Analysis -- Chapter 5. Discussion -- 5.1. Mass Balance -- 5.2. Mine -- 5.3. Smelter -- 5.4. Refinery -- Chapter 6. Conclusions -- 6.1. Future Directions -- References