Dioxide Purification Research Articles

Research on the carbon neutralization of hot mix asphalt pavement based on life cycle assessment theory

The goal of reducing carbon emissions in the field of road engineering has become an important deployment strategy. Based on the life cycle assessment (LCA) theory, the environmental impact assessment and analysis of hot-mix asphalt pavement were carried out in this work on the basis of collecting and investigating the environmental load list data of hot-mix asphalt pavement. According to different life cycle stages, corresponding carbon neutralization schemes were proposed, and the optimal carbon neutralization schemes at different stages were obtained by simulation using queuing theory. The results showed that in the whole life cycle of hot mix asphalt pavement, the construction stage had the highest energy consumption and carbon emissions compared to the other stages, and its global warming potential (GWP) and Chinese abiotic depletion potential (CADP) were also the highest, with the greatest impact on the environment. Compared to other stages, the repair and demolition stage had the smallest contribution to the GWP and CADP evaluation indicators. In the material production stage, the ASRT 5A zeolite adsorbent had the best adsorption effect on carbon dioxide gas. The carbon emissions generated during the production phase of the neutralization material required an ASRT 5A zeolite adsorbent of about 83 kg. Michelia chapensis exhibited the best carbon dioxide purification effect compared to the other three trees during the transportation construction and maintenance disassembly phase. Michelia chapensis required a leaf area of about 28,016 m2 to neutralize the carbon dioxide emissions generated in these two stages.

A large-area MOF-based membrane for challenging CO2 purification and ethanol/CO2/N2 ternary mixture separation

Bioethanol has garnered widespread attention as a potential substitute for traditional fossil fuels. Focusing on the treatment of bioethanol fermentation exhaust is crucial for optimizing bioethanol recovery and achieving carbon dioxide (CO2) purification. This study successfully achieved the large-scale synthesis of zeolitic imidazolate framework-8 (LSZIF-8), which was then incorporated into polydimethylsiloxane (PDMS) to fabricate large-area ZIF-8/PDMS/PVDF mixed matrix membranes (MMMs) for bioethanol recovery from fermentation exhaust via vapor permeation (VP) processes. The ZIF-8/PDMS/PVDF MMMs exhibited a 1.5-time increase in ethanol permeability and selectivity improved by 1.7 times compared to the PDMS/PVDF membrane. The mass transport behavior of ethanol and CO2 molecules within the membrane, as well as examining the interactions between different components was systematically explored. It delves into the disparities in separation performance between PDMS/PVDF membrane and ZIF-8/PDMS/PVDF MMMs with nitrogen (N2), water vapor as the third component. Notably, high-quality LSZIF-8 crystals serves as a crucial source of raw materials for the continuous preparation of high-performance MMMs, addressing the limitation of traditional nanoparticle fillers in terms of scalability for production. This study paving new avenues for purifying fermentation exhaust and recovering bioethanol, while simultaneously present significant potential for industrial applications.

REDUCTION OF OCCUPATIONAL RISKS FOR THE HEALTH OF WORKERS AND IMPROVEMENT OF ECOLOGICAL SAFETY OF THE ENVIRONMENT DURING CLEANING OF INDUSTRIAL EMISSIONS OF METALLURGICAL ENTERPRISES

Purpose: prevention of occupational risks and reduction of the negative impact on the health of workers of industrial flue gases, along with the improvement of environmental safety thanks to mathematical modeling regarding the rationalization of technological indicators of sulfur removal at production enterprises. Design / methodology / approach: the use of regression analysis is implemented as the main research method. Conclusions: a multifactorial mathematical model of the dependence of the degree of reduction of the content of sulfur dioxide in gaseous products on the technological parameters of flue gas filtration was built using industrial data. This makes it possible to rationalize the technological parameters of production with further regulation of the sulfur dioxide purification process to increase its efficiency. Achieving a reduction in flue gas pollution with sulfur dioxide contributes to reducing the harmful effects on the health of workers, preventing occupational risks, and increasing the level of environmental safety. Limitations / implications of the research: the interrelationship of desulfurization production parameters was investigated in certain intervals according to the features of the technological process, which determines the corresponding limitations of the use of the constructed mathematical model. Practical consequences: the interrelationship of technological indicators of industrial production is determined, which allows adjusting the value of the degree of purification of flue gases from sulfur dioxide when changing the technological parameters of filtration with the establishment of the most favorable conditions. The obtained results can be used to improve the production process of enterprises whose activities are accompanied by gaseous emissions: metallurgical plants, thermal power plants, etc. Originality / value: a multifactorial mathematical model of the dependence of the degree of purification of flue gases from sulfur dioxide on the technological parameters of the industrial process was built. The obtained results were presented in the form of a multivariate regression equation. On the basis of the obtained dependence, for a better visual perception, graphs were constructed in the form of surfaces, respectively, for some of the studied technological parameters.

G-OPTIMAL DESIGN OF NON-LINEAR MODEL TO INCREASE PURITY LEVELS OF SILICON DIOXIDE

Silicon Dioxide (SiO2) is one of the most abundant minerals found on earth. SiO2 is widely used in various fields, so its availability as a finite natural resource diminishes. A purity procedure can raise the purity of low-quality silica by altering the temperature and rate of temperature rise. This study aims to obtain the best design for increasing SiO2 levels—the G-optimal design on a non-linear model using the Variable Neighborhood Search (VNS) algorithm. The VNS algorithm employs two types of neighborhoods, one acquired by replacing one design point with a candidate set and the other by replacing two design points with two points in the candidate set. The model used to increase silicon dioxide's purity is a non-linear model that follows the exponential decay distribution. The best design points obtained from the G-optimal design on the relationship between temperature (oC) and the rate of temperature increase (oC/min) 800 oC to 900 oC is a pair of points 800 oC and 1,67 oC /min, 800 oC and 2,17 oC/min, 815 oC and 2,50 oC/min, 825 oC and 2,00 oC/min, 845 oC and 2,34 oC/min, 895 oC and 3,34 oC/min 900 oC and 3,50 oC/min with a G-efficiency of 96,41%.

Performance optimization of an HT-PEMFC and PSA integrated system with impure hydrogen containing CO2

• An integrated system consisting of PEMFC and PSA for CO 2 separation is proposed for exploring the optimal performance. • A parameter is defined to quantify toxic effect of CO 2 on the PEMFC performance. • The system is optimized from the perspective of toxic effect and PSA correction. • It is not necessary to feed the system with pure H 2 to obtain better performance. Hydrogen produced by the natural gas steam reforming method contains impure gas, and feeding such a mixture into a proton exchange membrane fuel cell will result in poor power density and efficiency performance. To improve the devastating performance resulting from this situation, an innovative system that integrated a high-temperature proton exchange membrane fuel cell (HT-PEMFC) and a pressure swing adsorption (PSA) device is proposed in this study to explore the system performance when impure hydrogen with carbon dioxide is used. Two parameters for these two devices were investigated to ensure the validity and reliability of the novel system. The results show that the maximum power of the integrated system was 0.1204 W, this power increased by 16.1% from that obtained when using impure hydrogen in the HT-PEMFC, and the efficiency of the integrated system maintained a high value of 46%. Consequently, the feasibility of the new system was proven by the simulation results. Finally, the extended analysis of this study shows that in order to reduce the energy consumption and maintain the performance of fuel cell, the carbon dioxide purification concentration from the PSA device should be set 1% to get a maximum output power and be set 5% to get a maximum efficiency.

Carbon dioxide extraction from marine engine exhaust gases by the method of adsorption

The purpose of the article is to analyze a method of marine engine exhaust gases carbon dioxide purification by means of adsorption which proceeds in parallel with the process of steam condensation formed during the combustion of fuel in a diesel cylinder. The scheme of afacility of advance efficiency for marine engine exhaust gases purifying is given. This facility works with the use of granulated slag pumice as an adsorbent for exhaust gases harmful components and ozone as an oxidant in order to accelerate the purification process. A full-scale test was conducted in order to check the efficiency of the facility and evaluate its effectiveness in engine discharge gases purifying. Aformula is received for a conduction of a calculation of the carbon dioxide purifying degree in the experimental facility which contains in the engine exhaust gases depending on a crankshaft rotation speed.

Улучшение технологических индикаторов полуфабрикатов производства сахара из бактериально инфицированной сахарной свеклы

Introduction. Technological aids play a special role in sugar production technology, but their complex effectiveness requires a comprehensive and in-depth study. The research objective was to establish the patterns of change in the technological indicators of semi-finished products obtained from bacterially infected sugar beets with the combined use of an enzyme preparation, antimicrobial agent, and defoamer.
 Study objects and methods. The study involved such semi-finished products as juice (diffusion, pre-defecated, first and second saturation) and syrup, the quality of which was determined according to standard methods. The laboratory experiment was carried out on the basis of the second-order D-optimal Box-Behnken plan for three factors at three levels.
 Results and discussion. The research revealed positive dynamics of the following technological indicators: sucrose content, deposition rate, turbidity, chromaticity, and general purification effect. The sugar beet had the second degree of infection with mucous bacteriosis. Purified juice underwent lime-carbon dioxide purification and thickening under the combination of enzyme preparation Dextrasept 2, antimicrobial agent Betasept, and antifoam agent Voltes FSS 93. The greatest increase in sucrose at the level of 1.1% by DM weight was confirmed by a higher overall effect of purification of diffusion juice (2.2 %). The values of turbidity of the purified juice and syrup were below the threshold values. The low values resulted from the increase in the sedimentation rate of the pre-defective juice and the juice of the first saturation by an average of 4.1 and 3.2 times, respectively, due to the effective removal of high molecular weight compounds. The share of the enzyme preparation was 40–71%, antimicrobial agent – 19–49%, defoamer – 1.6–6.5%. The values of the multicriteria optimization parameter corresponded with technological indicators. The optimal combination (per 1000 tons of beets) included 6–8 kg of Dextrasept 2, 1.5–2.0 kg of Betasept, and 15–20 kg of Voltes FSS 93. As a result, the yield of white sugar increased by 0.25%. 
 Conclusion. The regression dependencies can be recommended for predicting the main technological indicators of semi-finished products. The resulting data makes it possible to determine the effectiveness of the combined use of an enzyme preparation, antimicrobial agent, and defoamer in sugar production. Further research will identify the patterns of multifactorial interaction of these preparations.

Updating technological modes for concentrated sugar-containing solutions purification

Existing technological schemes of lime-carbon dioxide purification of diffusion juice include lime treatment (defecation) and two-stage treatment with carbon dioxide (saturation) with sediment separation. Improving cleaning methods aimed at increasing its efficiency is an urgent task. Lime-carbon dioxide purification of the concentrated sugar-containing solution before boiling allows to improve the quality of sugar, reducing the syrup color and increasing its natural alkalinity. The proposed purification scheme, which includes overcarbonation to low syrup pH values (8 and below), its mixing with carbonated syrup and adding activated suspension of II saturation sediment, makes it possible to obtain a purified solution with an increased effect of adsorption purification, with a significantly low content of high-molecular compounds and their calcium salts. The results of the study of various schemes for the purification of syrups in a laboratory setup have been presented. A method for purification of concentrated sugar-containing solutions, protected by a patent of the Russian Federation for the invention, has been developed, which provides for the reduction in the consumption of calcium hydroxide by 0,10–0,12% of CaO by weight of the product or by 0,04% by weight of beet.

Innovative Developments for the Disposal of Spent Ethanolamines from a Carbon Dioxide Purification Unit on Ammonia Aggregates

Various options are considered for the processing of large-capacity waste of ethanolamines generated during long-term operation as absorbents in technological processes of carbon dioxide extraction from converted gas (from a mixture of CO2and hydrogen) in the production of ammonia type AM-76 and accumulation flue gas. Various innovative methods have been proposed for the disposal of spent mono- and methyldiethanolamines, which are in demand in various industries: in the process of urea condensation with a formaldehyde-containing product in the synthesis of adhesive and impregnating resins for woodworking, in the production of high-quality synthetic drying oils and substitutes for titanium white, in the manufacture of flame retardants and molding mixtures for metal structures and foundry molds in the metallurgical industry, when refining oil from hydrogen sulfide and mercaptans. This allowed us to solve the important environmental problem of the disposal of toxic waste, optimize the operation of a number of industries and reduce their environmental impact.

Влияние ферментативной обработки на качество технологических соков при производстве сахара из бактериально инфицированной сахарной свеклы

Объектом исследований служили корнеплоды инфицированной слизистым бактериозом сахарной свеклы, клеточный сок и полуфабрикаты свеклосахарного производства. Цель исследований заключалась в установлении закономерностей изменения качества технологических соков при введении ферментного препарата гликозидазного действия в процессе экстрагирования сахарозы из бактериально инфицированной сахарной свеклы. Теоретически обоснованы предпосылки применения гликозидазных ферментных препаратов при переработке бактериально инфицированной сахарной свеклы. На основе физического и математического моделирования процессов экстрагирования сахарозы и известково-углекислотной очистки диффузионного сока выявлены зависимости изменения технологических показателей от дозы введения гликозидазного ферментного препарата и степени инфицированности слизистым бактериозом клеточного сока сахарной свеклы. Показана роль ферментативной обработки в улучшении качества технологических соков, в том числе увеличении содержания сахарозы в очищенном соке в среднем на 2,2%, повышении эффекта очистки диффузионного сока в среднем на 3,5%, снижении мутности очищенного сока – на 20%, что может обеспечить повышение качества и выход белого сахара на 1,1%. Достигнуто требуемое состояние пищевой системы с оптимальными (максимальными) показателями величины коэффициента желательности от 0,63 до 0,99, что соответствует хорошему и очень хорошему уровню в зависимости от степени инфицированности корнеплодов. Дальнейшие исследования будут направлены на обоснование условий рационального применения ферментных препаратов гликозидазного действия в оптимальной комбинации совместно с другими технологическими вспомогательными средствами при экстрагировании сахарозы из бактериально инфицированной сахарной свеклы.

The state of the food system of diffusion juice of sugar beet infected by mucous bacteriosis with the introduction of enzyme preparations of glycosidase action

In sugar technology, the degree of sucrose extraction from sugar beet is largely determined by the state of the food system of diffusion juice formed during the extraction of sucrose from beet chips. Potential states of the food system of diffusion juice obtained from healthy and infected sugar beet under the condition of optimal technological regime and technological aids used are shown. It is noted that the food system of the diffusion juice from the infected with mucous bacteriosis sugar beets shows a tendency to instability due to the accumulation in it of hard removable polysaccharide high-molecular compounds - dextran,Levan ,effective way to remove which are enzyme preparations of glycosidase action (dextranase and Lebanese). The state of the food system of the diffusion juice from sugar beets with the extent of mucous bacteriosis lesions of 5 and 10% is studied, based on the modeling of technological processes of sucrose extraction and lime-carbon dioxide purification of diffusion juice by means of diagnosing representative indicators. As used auxiliary substances used complex enzyme-antiseptirujut drug Extrasept 2, containing dextranase and Levanzo; antifoam Laprol PS-1; antimicrobial agent Navisan M1. It is identified that the introduction of the specified enzyme preparations into the food system of the diffusion juice promotes its transfer into stable state with the best values of the parameters: the content of high molecular compounds were lower by 42–44%; the purity was higher by 2,5–2,6%; dynamic viscosity by 10–15% lower as compared to the variants without application of enzyme preparations. This is due to the hydrolyzing effect of enzyme preparations, confirmed by the results of the microscopy of cellular and diffusion juices. Stable state of the food system of diffusion juice contributed to the improvement of the quality indicators of the purified juices.

The influence of exhaust gas compositions in MnO2 dry DeSO x filter for diesel emission control

ABSTRACT Sulfur dioxide purification has adverse effects on the environment and the human body. In this study, the dry desulfurization process from exhaust gas exhaust by dry DeSO x filter is investigated for constructing a sulfur-based capture-and-reuse system. The activated MnO2 having a high-specific surface area (HSSA MnO2) is utilized as an absorbent to indicate high SO2 capture performance in the low-temperature region. To improve the capture performance, (SO2 concentration, space velocity, and gas composite) is analysed on SO2 capture performance of dry DeSO x filter. Results showed that SO2 capture performance in high SO2 concentration was constant regardless of space velocity. However, in low SO2 concentration, the SO2 capture performance decreased with increasing space velocity. Moreover, the presence of H2O in the flow gas exhibited a beneficial effect on SO2 capture performance.

Dynamic simulation in development of contemporary energy systems – oxy combustion case study

Engineering efforts to handle contemporary energy supply challenges and mitigate pollutant emission lead towards more complicated systems. Power plants are supplementing with additional processing units, alternative production modes and higher level of automation. Wind and solar sources, biomass combustion, gasification, carbon capture and storage (CCS), and cogeneration have appeared as important players in the energy systems. The increasing complexity comprises a risk that the systems become less manageable and less stable than currently. Traditional steady-state engineering methods cannot fully address these challenges that are inherently dynamic in their nature. Dynamic process simulation appears as important tool to the systems design and optimisation tasks.A large variety of dynamic process modelling and simulation approaches has been presented recent years. This paper presents a brief review of methods and simulation packages that are generally applied for studying energy systems' transient behaviour. A CCS capable power plant is presented as an example of utilizing dynamic process simulation for virtual evaluation of a novel electricity production concept. The modelling was performed using two simulators Apros and Aspen Plus Dynamics, which were linked together for dynamic simulating the full chain of cryogenic oxygen distillation, oxy combustion, turbine islands and carbon dioxide purification and liquefaction operations.

Carbon Capture and Utilization Technology without Carbon Dioxide Purification and Pressurization: A Review on Its Necessity and Available Technologies

Carbon capture and utilization (CCU) has attracted increased attention as a means to mitigate and adapt to climate change. CCU technology regards CO2 as a raw material and reduces CO2 emissions. Ho...

Sensitivity and Techno-Economic Analysis of Leading Oxy-Combustion Power Cycles with Full Carbon Capture: NetPower and Supercritical CES

The increasing concern on climate change has led to global efforts to reduce carbon dioxide (CO2) in the environment. It appears that by far the largest contribution to the greenhouse effect stems from emissions of carbon dioxide CO2. A large part of the CO2 emission are produced by the combustion of fossil fuels in conventional power plants and industrial processes. However, the Carbon Capture and Sequestration (CCS) technologies have been developed to minimise the CO2 emission to the atmosphere. Three main capture technologies (pre-combustion, post-combustion and oxy-fuel combustion) have been mainly developed for solid fuels (e.g., coal, biomass) combustion systems. However, there are many gas-fired power plants and industrial process burning natural gas as a cleaner fuel. Natural gas has the lowest CO2 emissions per unit of energy of all fossil fuels at about 14 kg C/GJ, compared to oil with about 20 kg C/GJ and coal with about 25 kg C/GJ. Although gas-fired plants emit less CO2 but still to achieve the environmental goals of the Paris Agreement it is essential to develop CCS technologies for the growing gas-fired systems. Among the available technologies, turbine-based oxy-combustion cycles (Oxyturbine cycles) are one of the most suitable carbon capture technologies for the gas-fired power plants. In this technology, natural gas is burned with pure oxygen, and temperature moderation is done by Flue Gas Recirculation (FGR) so that the exhaust gas includes mainly CO2 and water vapour ready for sequestration and storage. Recent developments in oxy-combustion technology have reduced the cost of capture and made it competitive with post- combustion technology. Several oxyturbine cycles have been introduced by means of thermodynamic analysis. However, only NetPower and Supercritical CES cycles have recently proceeded to the demonstration phase. The NetPower cycle recirculates only carbon dioxide as the working fluid, and the Supercritical CES cycle uses water as its working fluid. The Supercritical CES cycle that has best efficiency among other type of CES cycles includes high, medium and low-pressure turbines (HP, MP, and LP) and the exhaust gas from the high-pressure turbine is reheated and expanded in an MP and LP. Pure oxygen is produced in an Air Separation Unit (ASU) and directly inject into the combustion chamber. The NetPower cycle includes a single turbine with high inlet pressure and a main multi-stream heat exchanger. Pure oxygen is produced in the ASU and mixed with the recycled carbon dioxide, before being introducing to the combustion chamber. Both cycles include recycling loops and carbon dioxide purification sections. These novel cycles reduce the cost for power generation with complete CO2 capture and sequestration with nearly zero emission. In this paper, The NetPower and Supercritical CES Cycles are investigated by means of process simulation and the technologies and utilised facilities compared using sensitivity analysis. Both cycles are simulated with Aspen Plus software with the same initial conditions, and the simulation results are compared with IEA 2015 report for validation. The sensitivity of both cycles are analysed with respect to the Turbine Inlet Temperature (TIT), Combustion Outlet Pressure (COP) and Heat Exchanger Approach Temperature (HET). The efficiencies are extracted for both the NetPower and CES cycles, and partial load behaviour of the cycles are investigated. The initial results show that the NetPower cycle is more sensitive to the Turbine Inlet Temperature (TIT) variations in comparison with S-CES cycle. The results of this paper provide a platform for a comprehensive techno-economical and sensitivity analysis of the NetPower and Supercritical CES Cycles as the leading Oxy-combustion power cycles with full carbon capture.

Sequential Oxygen Reduction and Adsorption for Carbon Dioxide Purification for Flue Gas Applications

Sequential Oxygen Reduction and Adsorption for Carbon Dioxide Purification for Flue Gas Applications

Sequential Oxygen Reduction and Adsorption for Carbon Dioxide Purification for Flue Gas Applications

Sequestration or utilization of carbon dioxide (CO2) produced from fossil fuels depends on the ability to transform flue gas into purified streams. Recent developments in oxy‐combustion have improved the efficiency of energy generation and carbon capture (>90% CO2). The subsequent removal of oxygen (O2) from this flue gas is critical, but such a process is energy intensive, technologically challenging, and unsolved. Herein, a simulated flue gas stream is purified by the catalytic conversion of oxygen using methane (CH4). The supported palladium (Pd) catalyst selectively reduces oxygen to an effluent gas with 99.7% CO2 and 0.3% O2. Using a higher Pd loading has no impact on the oxygen conversion, whereas feeding excess CH4 decreases the selectivity to CO2. A complete removal of O2 is achieved using a copper‐based oxygen scavenger placed after the Pd catalyst bed, yielding a 100.0% pure CO2 stream.

Manganese Dioxide Purification Methods for Producing Tantalum Capacitors with Low Equivalent Series Resistance

Manganese Dioxide Purification Methods for Producing Tantalum Capacitors with Low Equivalent Series Resistance

Manganese Dioxide Purification Methods for Producing Tantalum Capacitors with Low Equivalent Series Resistance

Manganese Dioxide Purification Methods for Producing Tantalum Capacitors with Low Equivalent Series Resistance

Integrated oxyfuel power plant with improved CO2 separation and compression technology for EOR application

An integrated advanced supercritical coal-fired oxyfuel power plant with a novel cryogenic CO2 separation and compression technology for high purity CO2 to suit injection for Enhanced Oil Recovery purposes is investigated. The full process is modelled in Aspen Plus® consisting of: an Air Separation Unit (ASU), an Advanced Supercritical Pulverised Fuel (ASC PF) power plant with a bituminous coal as feedstock, a steam cycle, and a Carbon dioxide Purification Unit (CPU). The proposed CPU process accommodates a distillation column with an integrated reboiler duty to achieve a very high purity CO2 product (99.9%) with constrained oxygen levels (100ppm). This work presents a detailed analysis of the CO2 separation and compression process within the full power plant, including effective heat integration to reduce the electricity output penalty associated with oxyfuel CO2 capture. The results of this analysis are compared with previous studies and indicate that the combined application of process optimisation in the CPU and advanced heat integration with the power plant offer promising results: In this work a high purity CO2 product was achieved while maintaining 90% capture for a net plant efficiency of 38.02% (LHV), compared with a thermal efficiency of 37.76% (LHV) for a reference simulation of an ASC PF oxy-fired plant with advanced heat integration, providing a lower purity CO2 product.