Top Gas Research Articles

Modeling and Optimization of Biochar Injection into Blast Furnace to Mitigate the Fossil CO2 Emission

Most modern blast furnaces (BFs) operate with Pulverized Coal Injection (PCI), but renewable and carbon neutral biochar could be applied to reduce the fossil CO2 emission in the short term. In the present study, heat and mass balance-based model (MASMOD) is applied to evaluate the potential of biochar in partial and full replacement of injected pulverized coal (PC) in the ironmaking BF. The impact of biochar injection on the raceway adiabatic flame temperature (RAFT) and top gas temperature (TGT) is evaluated. Three grades of biochar, produced from the pyrolysis of sawdust, were evaluated in this study. The total carbon content was 79.2%, 93.4% and 89.2% in biochar 1, 2 and 3, respectively, while it was 81.6% in the reference PC. For each type of biochar, 6 cases were designed at different injection levels from 30 kg/tHM up to 143 kg/tHM, which represent 100% replacement of PC in the applied case, while the top charged coke is fixed in all cases as reference. The oxygen enrichment, RAFT, and TGT are fixed for certain cases, and have been calculated by MASMOD in other cases to identify the optimum level of biochar injection. The MASMOD calculation showed that as the injection rate of biochar 1 and biochar 2 increased, the RAFT increased by ~190 °C, while TGT decreased by ~45 °C at 100% replacement of PC with biochar. By optimizing the moisture content of biochar and the oxygen enrichment in the blast, it is possible to reach 100% replacement of PC without much affecting the RAFT and TGT. Biochar 3 was able to replace 100% of PC without deteriorating the RAFT or TGT.

Intermittency in Wind Energy and Emissions from the Electricity Sector: Evidence from 13 Years of Data

Renewable subsidies and mandates currently play a central role in the environmental and energy policy in the United States, one of the world’s top greenhouse gas emitters. Therefore, accurately estimating the environmental benefits from wind energy is key to evaluating the existing policies and setting future directions and has been studied within a growing body of the literature. However, most of the existing studies do not take the intermittency into account, and the small number of studies that do only study a relatively short time period limiting the extent to which they can be informative within different ranges of wind generation capacity. In this paper, we present the first estimates of the environmental benefits of wind energy generation using a dataset that spans well over a decade. Specifically, we use 13 years of hourly and sub-hourly data to estimate the causal effect of wind generation and its intermittency on CO2, NOx, and SO2 emissions from the electricity sector in Texas. Additionally, we compared the full sample results to those from sub-samples where the dataset is divided into subgroups based on wind output level. We found that while wind generation clearly has a statistically significant negative marginal effect on all pollutants we studied, the marginal effect of intermittency varies across different wind output levels in a highly irregular way. Our findings suggest that conducting pooled analyses has the potential to mask the irregularity in the variation of the effect of intermittency in wind generation across different wind output levels.

Hysis Simulation Optimization of Distillation Desulfurization for Mixed Light Hydrocarbons in Tahe Oil Field

In order to improve the performance of distillation desulfurization unit for mixed light hydrocarbons in Tahe Oil Field, HYSIS simulation investigation was performed. The influences of feed temperature, operation pressure, reboiler temperature and plate number on sulfur content of bottom product, flow rate of product, energy consumption and saturated vapor pressure of light hydrocarbons were carefully discussed. It is indicated that the total energy consumption can be reduced by 45.78% if the unit is operated at the optimized conditions. Meanwhile, the sulfur content of the bottom product will be less than 0.05% and the flow rate of bottom product can be increased by 2.04 t/d while the flow rate of top gas product can be decreased up to 754.11 Nm3/d. In addition, the saturated vapor pressure of light hydrocarbons is lower than the operation pressure.

Investigating the Dynamics between Blast Furnace Flame and Top Gas Temperature with CFD

Investigating the Dynamics between Blast Furnace Flame and Top Gas Temperature with CFD

Monitoring the Blast furnace working state by a combination of innovative measurement techniques

At blast furnace B at Salzgitter Flachstahl a series of innovative measuring techniques are installed to monitor the processes at the blast furnace top, making this furnace one of the best equipped furnaces in Europe. These techniques comprise full 2D measurement of the temperature profile of the top gas shortly above the burden surface, 3D radar scan of the whole burden surface and online measurement of the dust concentration in the top gas. After more than 5 years’ experience with most of these techniques, they enable to better understand the complex chemical and physical interrelations occurring in the BF stack between the ascending process gas and the descending solid burden. A couple of examples of incidents that were monitored are presented in this article, including influences of charging programmes on top gas temperature profiles and influences of disturbed gas solids interaction on the BF working state. The new measuring techniques with tailor-made data processing enable the operators to gain a better picture of the processes currently occurring in the blast furnace, consequently supporting them in keeping the blast furnace operation as stable and efficient as possible.

Adaptation of the Rist Operating Diagram as a Graphical Tool for the Direct Reduction Shaft

The blast-furnace operating diagram proposed by Rist was revised to direct reduction and was specifically applied to the Midrex NGTM process. The use of this graphical tool in the study of an industrial process highlighted the staggered nature of the reduction in the shaft furnace with, in particular, the existence of a prereduction zone in the upper part where metallization is thermodynamically impossible. A sensitivity study also showed the impact of the in situ reforming rate on the ability of the gas to completely reduce iron oxides. Finally, we graphically defined the minimum quality required for the top gas to produce direct-reduced iron.

Revisiting the Rist diagram for predicting operating conditions in blast furnaces with multiple injections.

Background: The Rist diagram is useful for predicting changes in blast furnaces when the operating conditions are modified. In this paper, we revisit this methodology to provide a general model with additions and corrections. The reason for this is to study a new concept proposal that combines oxygen blast furnaces with Power to Gas technology. The latter produces synthetic methane by using renewable electricity and CO 2 to partly replace the fossil input in the blast furnace. Carbon is thus continuously recycled in a closed loop and geological storage is avoided. Methods: The new model is validated with three data sets corresponding to (1) an air-blown blast furnace without auxiliary injections, (2) an air-blown blast furnace with pulverized coal injection and (3) an oxygen blast furnace with top gas recycling and pulverized coal injection. The error is below 8% in all cases. Results: Assuming a 280 t HM/h oxygen blast furnace that produces 1154 kg CO2/t HM, we can reduce the CO 2 emissions between 6.1% and 7.4% by coupling a 150 MW Power to Gas plant. This produces 21.8 kg/t HM of synthetic methane that replaces 22.8 kg/t HM of coke or 30.2 kg/t HM of coal. The gross energy penalization of the CO 2 avoidance is 27.1 MJ/kg CO2 when coke is replaced and 22.4 MJ/kg CO2 when coal is replaced. Considering the energy content of the saved fossil fuel, and the electricity no longer consumed in the air separation unit thanks to the O 2 coming from the electrolyzer, the net energy penalizations are 23.1 MJ/kg CO2 and 17.9 MJ/kg CO2, respectively. Discussion: The proposed integration has energy penalizations greater than conventional amine carbon capture (typically 3.7 - 4.8 MJ/kg CO2), but in return it could reduce the economic costs thanks to diminishing the coke/coal consumption, reducing the electricity consumption in the air separation unit, and eliminating the requirement of geological storage.

A Numerical Study on the Performance of the H2 Shaft Furnace with Dual-Row Top Gas Recycling

Given the urgent pursuit of carbon neutrality and stringent climate policies, the H2 shaft furnace (H2-SF) is starting to gain widespread attention in the steel industry. In this study, the performance of the H2-SF under operation with a dual-row injection top gas recycling system was investigated by a one-dimensional mathematical model. The potential of microwave heating as a means to supply thermal energy in regions of energy deficit was also assessed briefly. The results showed that for scenarios without microwave heating, increasing the upper-row injection rate can improve the furnace performance, and increasing the distance of the upper-row injection level from the furnace top also has a positive effect. A high microwave heating efficiency is expected in regions above the upper-row injection level. For scenarios with microwave heating, a higher microwave power leads to a better furnace performance. Thus, a higher furnace productivity can be achieved by increasing either the upper-row injection rate or the microwave power. However, the latter seems more promising as it decreases the total energy demand due to a better utilization of thermal energy. Based on the comparison of two representative examples, the decrease in the total energy demand is about 0.2 GJ/t-Fe.

CO2 Abatement in the Steel Industry through Carbon Recycle and Electrification by Means of Advanced Polymer Membranes.

The potential of advanced polymer or hybrid polymer membranes to reduce CO2 emissions in steel production was evaluated. For this, a conceptual process design and assessment was performed for a process that is a combination of carbon recycling and electrification of the steel making process. The results indicate a CO2 avoidance of 9%. CO2 emissions were reduced by factor 1.78 when using renewable electricity according to the proposed scheme compared to feeding this renewable electricity to the electrical grid. The CO2 abatement potential of the studied concept is highly dependent on the CO2 conversion in the plasma torch. If CO2 conversion in the plasma torch could be increased from 84.4% to 95.0%, the overall CO2 avoidance could be further increased to 16.5%, which is comparable to the values reported for the top gas recycling blast furnace. In this case, the CO2 emissions reduction achieved when using renewable electricity in the proposed scheme compared to using the same electricity in the electrical grid increases a factor from 1.78 to 3.27.

CO2 Recycling in the Iron and Steel Industry via Power-to-Gas and Oxy-Fuel Combustion

The iron and steel industry is the largest energy-consuming sector in the world. It is responsible for emitting 4–5% of the total anthropogenic CO2. As an energy-intensive industry, it is essential that the iron and steel sector accomplishes important carbon emission reduction. Carbon capture is one of the most promising alternatives to achieve this aim. Moreover, if carbon utilization via power-to-gas is integrated with carbon capture, there could be a significant increase in the interest of this alternative in the iron and steel sector. This paper presents several simulations to integrate oxy-fuel processes and power-to-gas in a steel plant, and compares gas productions (coke oven gas, blast furnace gas, and blast oxygen furnace gas), energy requirements, and carbon reduction with a base case in order to obtain the technical feasibility of the proposals. Two different power-to-gas technology implementations were selected, together with the oxy blast furnace and the top gas recycling technologies. These integrations are based on three strategies: (i) converting the blast furnace (BF) process into an oxy-fuel process, (ii) recirculating blast furnace gas (BFG) back to the BF itself, and (iii) using a methanation process to generate CH4 and also introduce it to the BF. Applying these improvements to the steel industry, we achieved reductions in CO2 emissions of up to 8%, and reductions in coal fuel consumption of 12.8%. On the basis of the results, we are able to conclude that the energy required to achieve the above emission savings could be as low as 4.9 MJ/kg CO2 for the second implementation. These values highlight the importance of carrying out future research in the implementation of carbon capture and power-to-gas in the industrial sector.

Indices to monitor the root cause of circumferential imbalance in blast furnace

ABSTRACT Non-uniform distribution of burden is the main cause of circumferential imbalance in the blast furnace. Several techniques have been devised by researchers and blast furnace operators across the globe to quantify the circumferential imbalance in the blast furnace either by measuring the top gas composition or by assessing the amount of coke and ferrous burden charges across the circumference of the furnace. There is no work published for measuring the root cause of circumferential imbalance in the blast furnace due to non-uniform burden distribution. This paper aims to quantify the root cause of the circumferential imbalance in the furnace using different indices along with their formulation and implementation strategy in the blast furnace.

Experimental and Numerical Investigations on Charging Carbon Composite Briquettes in a Blast Furnace

In the present research, charging carbon composite briquettes (CCB) in a blast furnace (BF) was investigated. The CCB used contained 29.70 wt.% Fe3O4, 39.70 wt.%, FeO, 1.57 wt.% iron, 8.73 wt.% gangue, and 20.30 wt.% carbon. Its reaction kinetics in BF was examined by nonisothermal tests and modeled. Thereafter, the influence of replacing 10% ore with CCB on BF performance was studied by numerical simulations. Results showed that the CCB reaction behavior in BF could be modeled using the previously proposed model under ags = 1900 m2·m−3. Numerical simulations on a BF with a production of 6250 t hot metal per day (tHM/day) showed that replacing 10% ore with CCB efficiently improved the BF operation for coke saving. In the CCB charging operation, the CCB reached a full iron-oxide reduction above the cohesive zone (CZ) and a carbon conversion of 85%. By charging CCB, the thermal state in the BF upper part was significantly changed while it was not influenced in the BF lower part; the ore reduction was retarded before the temperature reached 1073 K and was prompted after and the local gas utilization tends to increase above the CZ. By the CCB reduction above the CZ, BF top gas temperature was decreased by 8 K, the BF top gas utilization was increased by 1.3%, the BF productivity was decreased by 17 tHM/day, the coke rate was decreased by 52.2 kg/tHM, and ore rate was decreased by 101 kg/tHM. Considering the energy consumption of sintering and coking, charging the CCB could have a significant energy-saving and CO2-emission-reducing effect for BF iron making.

Challenges and Outlines of Steelmaking toward the Year 2030 and Beyond—Indian Perspective

In FY-20, India’s steel production was 109 MT, and it is the second-largest steel producer on the planet, after China. India’s per capita consumption of steel was around 75 kg, which has risen from 59 kg in FY-14. Despite the increase in consumption, it is much lower than the average global consumption of 230 kg. The per capita consumption of steel is one of the strongest indicators of economic development across the nation. Thus, India has an ambitious plan of increasing steel production to around 250 MT and per capita consumption to around 160 kg by the year 2030. Steel manufacturers in India can be classified based on production routes as (a) oxygen route (BF/BOF route) and (b) electric route (electric arc furnace and induction furnace). One of the major issues for manufacturers of both routes is the availability of raw materials such as iron ore, direct reduced iron (DRI), and scrap. To achieve the level of 250 MT, steel manufacturers have to focus on improving the current process and product scenario as well as on research and development activities. The challenge to stop global warming has forced the global steel industry to strongly cut its CO2 emissions. In the case of India, this target will be extremely difficult by ruling in the production duplication planned by the year 2030. This work focuses on the recent developments of various processes and challenges associated with them. Possibilities and opportunities for improving the current processes such as top gas recycling, increasing pulverized coal injection, and hydrogenation as well as the implementation of new processes such as HIsarna and other CO2-lean iron production technologies are discussed. In addition, the eventual transition to hydrogen ironmaking and “green” electricity in smelting are considered. By fast-acting improvements in current facilities and brave investments in new carbon-lean technologies, the CO2 emissions of the Indian steel industry can peak and turn downward toward carbon-neutral production.

Transient State modeling of Industry-scale ironmaking blast furnaces

The dynamic multiphase flow in ironmaking blast furnaces (BFs) operation is a transient-state process, but it was widely modeled as steady-state in the past. It is necessary to understand the evolution of in-furnace phenomena after some operational parameters are changed. In this study, for the first time, a transient-state BF (TBF) model is developed to describe the dynamic in-furnace phenomena in terms of flow, thermal, and chemical behaviors, featuring respective chemical reactions in respective burden layers. The TBF model is validated against the measurements from an experimental BF. Then the TBF model is applied to a commercial BF of industry-scale and used to capture the time-evolution of velocity field, cohesive zone profile, thermal field, and gas utilization efficiency from an initial state to a steady state under given conditions. Moreover, the TBF model is used to study a specific BF operation change – hot burden charging, for TBF model capability demonstration, by capturing the time-evolution of the in-furnace phenomena at certain time intervals. It shows that, after charging the hot burden, the change of reacting flow can be more significant in the upper shaft regions compared to other regions, more important at near-wall region compared to the center region, and this largely happens in the first 8–10 h; besides, top gas temperature can rise to ∼ 800 K and coke rate is increased by ∼ 20 kg/tHM to maintain the BF productivity. This TBF model offers a cost-effective tool to understand the evolution of in-furnace behaviors in operation changes; and provide a basis for real-time understanding and control in future ironmaking.

An estimation model for cross temperature measuring in blast furnace ironmaking

ABSTRACT The cross temperature measuring device is applied to monitor the top temperature and gas flow distribution in the blast furnace (BF) during the ironmaking process. However, the temperature of the BF roof is relatively high, which causes damage to the cross temperature measuring device. Therefore, this paper proposes an efficient estimation method. First of all, the data filtering method are used to solve the problems of noise interference. Moreover, as the fact that BF cross temperature measurement is affected by interference factors, it is easy to cause information redundancy. Aiming at this, the maximum information coefficient (MIC) correlation analysis and sequence dislocation method are used to determine the input variables and its action time of the model. Finally, an estimation model based three-layer long and short-term memory network (LSTM3) is established. The experimental results show that the LSTM3 can estimate the centre temperature of cross temperature measuring device.

Computational analysis of hydrogen reduction of iron oxide pellets in a shaft furnace process

To gain a better understanding of the performance characteristics of a shaft furnace for hydrogen reduction of iron oxide pellets under operation with top gas recycling (TGR), a kinetic model was applied to investigate the coupled phenomena of gas-solid countercurrent reactive flow and heat transfer. The effects of operating parameters were studied for scenarios where the furnace is equipped with a single-row injection TGR system. The potential of a new TGR system featuring dual-row injection was also assessed preliminarily. The results showed that the productivity of the shaft furnace is much higher than in a syngas-based shaft furnace provided that a high mass flow of feed gas can be ensured to introduce adequate sensible heat. Hot charging of the pellets yielded an increase in the total energy consumption so the scope to reduce the gas mass flow by this method was found to be limited due to the poor heat utilization. By contrast, using a dual-row gas injection system was found to improve the performance, especially with respect to gas utilization and total energy consumption. This is chiefly attributed to a clear improvement in the thermochemical state of the furnace, which leads to a better utilization of the furnace volume.

Cost and environmental performance of forced air and hot water heating systems in post-Soviet countries

PurposeThe aim of the present study is to assess the selected heating systems (furnace and boiler) commonly used in the dwellings of seven post-USSR (the Union of Soviet Socialist Republics) countries. The systems were assessed in terms of their cost and environmental performance, with natural gas and electricity used as the main source of energy.Design/methodology/approachThe cost-effectiveness and environmental performance of the selected heating systems that have been commonly used in the selected post-USSR countries was assessed. Current energy (natural gas and electricity) prices that are applied in those countries were used.FindingsResults show that the furnace is the cheapest option, while natural gas is the cheapest source of energy, despite its high price in Tajikistan and Kyrgyzstan. Both heating systems could be considered eco-friendly options, although their efficiencies need to be considered at the design stage. Turkmenistan, Uzbekistan and Kazakhstan, which are the top natural gas producers, offer natural gas for the selected heating systems as both cost-effective and eco-friendly options.Practical implicationsA considerable reduction in electricity consumption and less harm to our environment can be achieved through the systems used in residential buildings in the region.Originality/valueThe outcomes of the present study offer value (in terms of cost-effective and eco-friendly options) for the end-users in the region.

Impact of Marcellus and Utica shale exploitation on Ohio, Pennsylvania, and West Virginia Regional Economies: A synthetic control analysis

AbstractWe use the synthetic control method to determine the economic impact of shale exploitation on Ohio, Pennsylvania, and West Virginia. Estimation results are mixed. The shale development decreased the poverty rate and increased the employment growth rate in Pennsylvania and West Virginia in the short run. Top oil and gas producing counties in West Virginia also experienced short‐term personal income growth due to fracking. However, most of the positive impacts disappeared a few years after the initial boom periods. The shale development did not bring significant economic benefits to Ohio. Further, shale drilling activities exert a potential long‐term negative effect on population growth in all three states.

An experimental modelling and performance validation study: Top gas pressure tracking system in a blast furnace using soft computing methods

The blast furnace is a master iron-producing plant of iron and steel factories and affected by several process parameters as well as top gas pressure , which is a key process control phenomenon to maintain stability and operational productivity in such plants. Blast furnace operation is not tolerant to any interruption, unbalanced operations, momentary disturbances or loss of control due to its nature of intensive chemical reactions and heat balance requirements. Consequently, it is crucial to monitor and control top gas system components of the furnace with instrumentation measurements to maintain stable, efficient operation and system safety ongoing. In this study, a novel top gas pressure tracking system is developed using the chronologically obtained live process data of Erdemir BF#2 in Turkey. Eight process parameters are considered as input parameters as per the plant maintenance team's recommendations and soft computing methods, artificial neural networks and adaptive neuro fuzzy inference system are employed and a statistical regression tool, autoregressive integrated moving average, is also applied for comparison. Performance and success ratio analysis is carried out using coefficient of determination ( R2), mean absolute percentage error and root mean squared error terms. The best performing model output for the adaptive neuro fuzzy inference system is found to be 0.95, 1.21 and 0.023, and slightly lower performance is obtained for the artificial neural network model with the output values of 0.94, 0.029 and 1.32 against R2, mean absolute percentage error and root mean squared error terms, respectively. The maximum prediction error is found to be 9.85% and 10.2%, and the average prediction error is found to be 1.19% and 1.29% for adaptive neuro fuzzy inference system and ANN models, respectively, for optimum simulations. The proposed neuro-fuzzy-driven top gas pressure prediction system is unique in the literature and should be integrated into existing control systems to improve operational awareness and sustainability or can be used as input guidance for a possible future top gas recovery system.

Synergistic Integrated Business Model-Sustainability-Technology of Top Malaysian Oil and Gas PLCs: The Moderating Role of United Nations SDG 5

Purpose – This study investigates the impact of the three main determinants of strengthening the sustainability practices of the oil and gas public listed companies of Bursa Malaysia (PLCs) through the Business Model, Sustainability and Technology synergistically compared between pre and post Malaysian Code of Corporate Governance 2017 (MCCG 2017).Design/methodology/approach – The study has followed the purposive sampling method followed by descriptive statistics, regression analysis and content analysis derived from the Malaysian Code of Corporate Governance 2012 (MCCG 2012) and the MCCG 2017 together with previous studies of the analysis of the annual reports and integrated reports in order to explore the reporting of the business model, sustainability and technology as a synergy.