Total Steam Research Articles

Techno-economic study of different process configurations of CO2 capture by MEA absorption and utilization of an MCDM method for their ranking

Carbon dioxide emissions from fossil fuel-fired power stations are attracting growing attention as a potential approach for reducing greenhouse gas emissions. Post-combustion capture of CO2 with monoethanolamine (MEA) is one of the most successful and mature technologies for mitigating carbon dioxide emissions. The most crucial problem of this technique is the high heat requirement of the reboiler for solvent regeneration. In this study, seven different configurations for carbon capture, namely, standard absorption, vapor recompression, vapor recompression process with split-flow, absorption column with intercooling, rich-split, combined, and rich-split with vapor recompression, are studied. The simulation results showed that the reboiler energy consumption intensity of alternative configurations lowered by 15.2 %, 18.4 %, 2.9 %, 7.4 %, 20.3 %, and 23.2 %, respectively, with regard to the standard absorption configuration. Seven configurations were ranked based on the total investment cost, steam consumption, power consumption, and water consumption. Combined and rich-split were the best, and vapor recompression and Rich-split with vapor recompression were the worst.

Industrial Park low-carbon energy system planning framework: Heat pump based energy conjugation between industry and buildings

The accelerating urbanization, rapid industrial development, and excessive consumption of fossil fuels pose survival challenges such as energy depletion and environmental degradation for humanity. In the context of industrial park development, constructing a low-carbon energy system, increasing the proportion of renewable energy, enhancing energy-level matching, and utilizing heat pumps for deep waste heat recovery are effective approaches to reduce fossil energy consumption and alleviate environmental pressures. Addressing issues such as diverse thermal flows in industrial sites, complex electricity-heat-cooling energy demands, and unclear industrial-building energy coupling mechanisms, this paper proposes a two-stage planning framework, comprising the following five steps: (1) constructing a waste heat utilization system centered around heat pumps, (2) establishing a mechanism for matching heat sources, equipment, and thermal sinks, (3) establishing an energy conversion model and energy quality quantification system, (4) optimizing waste heat utilization path allocation, and (5) conducting a system energy flow analysis. Case studies demonstrate that the proposed system achieves optimized matching of multiple heat sources and sinks in industrial and building scenarios through thermal integration, meeting diverse energy demands in the park, including electricity, cooling, and multi-grade heat. After coupling with traditional steam pipeline networks, the annual total cost and annual steam power consumption decrease by 33% and 39% respectively, with a waste heat contribution rate of up to 26% and a renewable energy penetration rate of up to 25%, and a waste heat recovery system payback period of 6 years. By establishing an energy quality quantification system and conducting multi-objective optimization considering losses and economic costs, this paper provides Pareto frontier solutions, offering references for engineering proposals. The proposed networked waste heat recovery system is characterized by low energy consumption and high economic efficiency, effectively integrating the energy characteristics of industrial parks and demonstrating engineering applicability.

Study on time-of-use pricing method for steam heating system considering user response characteristics and thermal storage capacity

Industrial steam heating is a significant aspect of energy consumption in China, playing a crucial role in industrial energy efficiency. Historically, demand response research has predominantly focused on the electricity sector, with limited emphasis on steam supply. This study explores a novel Time-of-Use pricing approach for steam heating systems, anchored in the demand response theory of price incentives. It develops a peak-valley segmentation method by considering both the load differences between supply and demand and the thermal storage capacity of the pipeline system. Additionally, the paper delves into user response characteristics to formulate an optimized Time-of-Use pricing model for steam heating systems. Implemented in a Jiangsu-based case study, the model demonstrates significant efficiency improvements: it reduces the peak-valley load difference by up to 68.3% and cuts steam purchasing costs by ¥135,000. Furthermore, the alignment between the users' total steam load curve and the heat source's steam supply is enhanced by 18.8%, illustrating the model's effectiveness in balancing demand and supply.

Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE-VT): A pilot study.

The utility of ablation index (AI) to guide ventricular tachycardia (VT) ablation in patients with structural heart disease is unknown. The aim of this study was to assess procedural characteristics and clinical outcomes achieved using AI-guided strategy (target value 550) or conventional non-AI-guided parameters in patients undergoing scar-related VT ablation. Consecutive patients (n = 103) undergoing initial VT ablation at a single center from 2017 to 2022 were evaluated. Patient groups were 1:1 propensity-matched for baseline characteristics. Single lesion characteristics for all 4707 lesions in the matched cohort (n = 74) were analyzed. The impact of ablation characteristics was assessed by linear regression and clinical outcomes were evaluated by Cox proportional hazard model. After propensity-matching, baseline characteristics were well-balanced between AI(n = 37) and non-AI(n = 37) groups. Lesion sets were similar (scar homogenization [41% vs. 27%;p = .34], scar dechanneling [19% vs. 8%;p = .18], core isolation [5% vs.11%;p = .4],linear and elimination late potentials/local abnormal ventricular activities[35% vs. 44%;p = .48], epicardial mapping/ablation [11% vs.14%;p = .73]). AI-guided strategy had 21% lower procedure duration (-47.27 min, 95% confidence interval[CI][-81.613, -12.928];p = .008), 49% lower radiofrequency time per lesion (-13.707 s, 95%CI[-17.86, -9.555];p < .001), 21% lower volume of fluid administered (1664 cc[1127, 2209] vs. 2126 cc [1750, 2593];p = .005). Total radiofrequency duration (-339 s [-24%], 95%CI[-776, 62];p = .09) and steam pops (-155.6%, 95%CI[19.8%,-330.9%];p = .08) were nonsignificantly lower in the AI group. Acute procedural success (95% vs.89%;p = .7) and VT recurrence (0.97, 95% CI[0.42-2.2];p = .93) were similar for both groups. Lesion analysis (n = 4707) demonstrated a plateau in the magnitude of impedance drops once reaching an AI of 550-600. In this pilot study, an AI-guided ablation strategy for scar-related VT resulted in shorter procedure time and average radiofrequency time per lesion with similar acute procedural and intermediate-term clinical outcomes to a non-AI-guided approach utilizing traditional ablation parameters.

The “Smart Home” Heat Supply System Based on District Heating with the Utilization of Secondary Energy Resources Using a heat Pump

One of the most important aspects of a “smart home” is its heating system, which should provide comfortable living conditions for residents while also being energy-efficient. This article discusses an innovative approach to heating systems in “smart homes” based on centralized heating with the utilization of secondary energy resources using a heat pump. The proposed heating system combines the advantages of traditional centralized heating and the efficiency of heat pumps. The article presents a calculated scheme, for which a temperature chart was developed. A methodology for calculating heat loads for both the traditional heating scheme and combined heat and power (CHP) with heat pumps is also proposed, and the necessary calculations were carried out. For clarity of the obtained data, a graph depicting the total steam load required for heating as a function of ambient temperature is constructed, as well as a graph showing the steam load as a function of the duration of the ambient temperature. The analysis of the data revealed that the use of heat pumps in CHP schemes reduces electricity generation by eliminating its production in the steam flow in the condenser. This facilitates the coverage of the electricity consumption schedule during periods of low demand for the integrated energy system. Additionally, integrating a heat pump into the heating system of the centralized heating system helps reduce energy dissipation and greenhouse gas emissions into the atmosphere, making heating more sustainable and environmentally friendly. Moreover, the proposed heating system for a “smart home” demonstrates high technical and economic performance, ensuring the investment attractiveness of such a project.

Possibilities Study of a Non-condensable Gas Exhaust System through the Condensate Injection Pipe at PLTP Wayang Windu

Wayang Windu Geothermal Power Plant, located in Pangalengan, Bandung regency, West Java with an installed capacity of 227 MWe has two units to generate electricity and deliver to the Jawa, Madura, and Bali grid. The steam extracted from the reservoir contains non-condensable gas of about 1-1.2% of total steam extracted, with the gas composition is CO2 92%, H2S 2%, NH3 0.1%, and residual gasses 4.9%. Possibilities study of a non-condensable gas exhaust through the condensate injection pipe was created as the efforts in the environmental conservation aspect for reducing carbon released to the atmosphere and reinjected back into the reservoir. This study was simulated in Wayang Windu Unit 2 by calculating the non-condensable gas flow rate from the gas removal system into the condensate injection pipe near of cooling tower blowdown power station area. The analysis result of this study indicates that the non-condensable gas requires a higher flow rate of condensate to dissolve the entire non-condensable gas, and may cause the slug flow pattern which would endanger the condensate pipeline system also destabilize the non-condensable gas exhaust operation process from the condenser through the gas removal system. To deal with this problem, the possibility of exhausting the non-condensable gas produced by the gas removal system can be alternated by flowing its non-condensable gas into a flash absorber system and converting its non-condensable gas into other eco-friendly products and power plant safe.

Hydrolysis phase equilibrium in various reactor configurations of the thermochemical Cu–Cl cycle

This study examines the phase equilibrium trends of the hydrolysis process in the thermochemical Cu–Cl cycle of hydrogen production. Various temperatures, pressures, and steam to copper ratios are modelled to predict CuCl2 conversion and progression of side reactions within the hydrolysis reactor. Novel reactor configurations, such as Moving Bed Reactors (MBRs), reactors in series and outlet gas recirculation are introduced within the analysis. Optimal conversion of CuCl2 and minimal by-product generation are obtained at a reactor temperature of 375 °C and pressure of 1 bar with improved conversion at higher temperatures and lower pressures. Improved reaction conversion is identified at higher steam to copper ratios. A 10:1 steam to copper ratio was used for the remaining reactor configuration scenarios. Reactors in series were simulated to mimic MBR behaviour. Three reactors in series with 10 kmol total steam consumption showed better conversion of 1 kmol of CuCl2 by 17% compared to a single reactor with the same steam inlet conditions. Mitigation of CuCl2 and Cu2OCl2 decomposition was also observed. The outlet gas recirculation improved the total desired product yield, however, the maximum conversion of CuCl2 was significantly impacted due to the high level of HCl concentrated steam. A combination of the gas outlet stream and reactors in series provide a method to improve the conversion rate. This reactor configuration is a challenging approach unless there is a separation technique to shift the reaction equilibrium or reduce HCl concentration within the gas stream.

Integration of machine learning and data analysis for the SAGD production performance with infill wells

AbstractThere have been numerous studies on predicting the production performance of the steam assisted gravity drainage (SAGD) process by data‐driven models with different machine learning algorithms since their introduction into industry. Similar efforts on SAGD infill wells, nevertheless, remain rare for this advanced alteration in improving the classical SAGD performance. On the other hand, predictive tools to optimize an infill well start time is useful in maximizing bitumen production and minimizing its costs. In this paper, a series of SAGD infill well models are constructed with selected ranges of operational conditions. Three SAGD infill well production performance indicators, namely, an increased ratio (), a total steam–oil ratio (SORtotal), and a stolen ratio () for each SAGD infill well, are calculated based on simulated infill well cases and control models. Five different machine learning algorithms (an artificial neural network [ANN] algorithm, three gradient boosting decision tree [GBDT] algorithms, and a support vector machine [SVM] algorithm) are trained, tested, and evaluated for their effectiveness in predicting those three indicators as output parameters, given seven SAGD relevant parameters as input parameters. Comparisons of different data sets show that the ANN is the best in predicting all three performance indicators under different infill well start times among all the above machine learning algorithms, while the GBDT algorithms have a better ability to learn a variation trend in the SAGD infill well performance.

Black liquor evaporators upgrade - How many effects?

Black liquor evaporation is generally the most energy intensive unit operation in a pulp and paper manufacturing facility. The black liquor evaporators can represent a third or more of the total mill steam usage, followed by the paper machine and digester. When considering an evaporator rebuild or a new system, the key design question is how many effects to include in the system. The number of effects is the main design feature that determines the economy of the system and the steam usage for a given evaporation capacity. A higher number of effects increases steam economy and reduces energy cost to a point, but additional effects also have higher initial capital cost and increased power costs. This research paper uses life-cycle cost analysis (LCCA) as a method to determine the optimum number of evaporator effects for a new evaporator system. The same basic principles and method can also apply to existing evaporator rebuild projects.

Thermal modeling and simulation of a single-flash geothermal power plant involving non-condensable gas: a case study of Kamojang geothermal field in Garut, West Java, Indonesia

The presence of non-condensable gases (NCGs) in a geothermal fluid disrupts the vacuum process in the condenser, reducing turbine efficiency and decreasing the total power output of the geothermal power plant (GPP). Therefore, to optimize the thermodynamic efficiency of a GPP, NCGs should be removed using a gas removal system. Since there is a substantial lack of design and simulation software for a GPP including NCG removal alternatives, in this study, we aimed to model and develop a software-based interface to simulate mass and energy balance involving an NCG fraction in a single-flash GPP as well as examine the thermodynamic performance of the gas removal system, which is the most important step in the planning and designing phase of a GPP. This software was validated using outputs of Kamojang GPP Units 2, 3, and 4 located at Kamojang geothermal field, Garut, West Java, Indonesia. Units 2 and 3 use two ejectors which are installed in series, and Unit 4 utilizes a hybrid system (HS) that is mostly a combination of vacuum pumps and a steam jet ejector (SJE). Our results showed that Kamojang GPP Units 2 and 3 generate 55.295 MW of power with an absolute error of 0.53%, whereas Unit 4 generates 60.218 MW of power with a 0.36% absolute error concerning the field data. These results correspond with the expected minimum error; therefore, our model’s parameters are considered valid and can be used for simulation. We found that using the simulation, the total steam saved by the HS at Kamojang GPP Units 2 and 3 was 534 kW. Furthermore, the net power production was reduced by 1.6% for the HS and 2.03% for the SJE with every 1% increase in the NCG fraction. The power requirement of the vacuum pumps remained less than the power generated by the motive steam which the ejector requires to dispose of the same amount of NCG, indicating that Kamojang GPP Units 2 and 3 will be more efficient if an HS is used.

Feasibility of implementation of solar thermal energy in steam-assisted gravity drainage (SAGD) in extra-heavy oil field in Colombia

The feasibility of implementing solar thermal energy in enhanced oil recovery (EOR) projects in Colombia has been practically avoided mainly owing to its high operating cost. However, Solar thermal energy can enable generating steam to be used for the EOR process with SAGD. Based on the amount of steam needed for an extra-heavy oil project, a solar thermal parabolic trough heat plant of 76.6 MWt for field application was designed to produce up to 261 MMBTU/h from computer simulated studies. This plant can generate injection steam during day hours and can be complemented with a steam conventional generation system for operating during night hours and on highly cloudy days. The obtained results showed the generated solar steam can contribute an average of 37.5% total daily steam requirement. By applying System Advisor Model (SAM), the produced solar steam can generate a saving of US$ 27602/day, which is signification saving of US$ 10.07 MM in one year. Therefore, the solar thermal parabolic trough heat technology can be a suitable option to implement in the Colombian Eastern Llanos Basin for thermal EOR.

Analysis of activated colloidal crud in advanced and modular reactor under pump coastdown with kinetic corrosion

The analysis of rapid flow transients in Reactor Coolant Pumps (RCP) is essential for a reactor safety study. An accurate and precise analysis of the RCP coastdown is necessary for the reactor design. The coastdown of RCP affects the coolant temperature and the colloidal crud in the primary coolant. A realistic and kinetic model has been used to investigate the behavior of activated colloidal crud in the primary coolant and steam generator that solves the pump speed analytically. The analytic solution of the non-dimensional flow rate has been determined by the energy ratio β. The kinetic energy of the coolant fluid and the kinetic energy stored in the rotating parts of a pump are two essential parameters in the form of β. Under normal operation, the pump's speed and moment of inertia are constant. However, in a coastdown situation, kinetic damping in the interval has been implemented. A dynamic model ACCP-SMART has been developed for System Integrated Modular and Advanced Reactor (SMART) to investigate the corrosion due to activated colloidal crud. The Fickian diffusion model has been implemented as the reference corrosion model for the constituent component of the primary loop of the SMART reactor. The activated colloidal crud activity in the primary coolant and steam generator of the SMART reactor has been studied for different equilibrium corrosion rates, linear increase in corrosion rate, and dynamic RCP coastdown situation energy ratio β. The coolant specific activity of SMART reactor equilibrium corrosion (4.0 mg s−1) has been found 9.63 × 10−3 μCi cm−3, 3.53 × 10−3 μC cm−3, 2.39 × 10−2 μC cm−3, 8.10 × 10−3 μC cm−3, 6.77 × 10−3 μC cm−3, 4.95 × 10−4 μC cm−3, 1.19 × 10−3 μC cm−3, and 7.87 × 10−4 μC cm−3 for 24Na, 54Mn, 56Mn, 59Fe, 58Co, 60Co, 99Mo, and 51Cr which are 14.95%, 5.48%, 37.08%, 12.57%, 10.51%, 0.77%, 18.50%, and 0.12% respectively. For linear and exponential coastdown with a constant corrosion rate, the total coolant and steam generator activity approaches a higher saturation value than the normal values. The coolant and steam generator activity changes considerably with kinetic corrosion rate, equilibrium corrosion, growth of corrosion rate (ΔC/Δt), and RCP coastdown situations. The effect of the RCP coastdown on the specific activity of the steam generators is smeared by linearly rising corrosion rates, equilibrium corrosion, and rapid coasting down of the RCP. However, the time taken to reach the saturation activity is also influenced by the slope of corrosion rate, coastdown situation, equilibrium corrosion rate, and energy ratio β.

Optimisation of Induced Steam Residual Moisture Content in a Clothing Conditioner Based on a Genetic Algorithm

This paper presents the modelling of heat and moisture transfer in a clothes-conditioning unit with the aim of improving the moisture content distribution to the clothes. A multicomponent, non-reacting, two-phase Eulerian–Eulerian model was utilised to solve the computational model. The clothes inside the conditioning unit were modeled as retangular towels (porous medium) of uniform thickness. Mass flow distribution of air and steam through the clothes was studied by systematically varying the steam nozzle angle (30° to 75°) and air inflow grill angle (45° to 105°). The simulation results were studied to identify the impact of design parameters on the mass flow distribution inside the clothes-conditioning unit. The mass flow of steam and the air–steam mixture were calculated through each towel in the forward and reverse direction. Response surface analysis was conducted to correlate the total mass flow rate and steam mass flow rate through each towel with the design variables. Moreover, a multiobjective genetic algorithm was employed to optimise the mass flow through the clothes and ascertain the optimal design configuration. The geometric configuration with a steam nozzle angle of 45° and air grill angle of 105° resulted in optimal steam and mixture distribution.

Modeling of Ventilation’s Influence on Energy Consumption in Multi-cylinder Dryer Section Part 2: Simulations and Applications

Ventilation system affects the water evaporation rate, energy consumption and the paper quality, which is considered as the largest optimization potential part of multi-cylinder dryer section. In this paper, energy consumption models of multi-cylinder dryer section are constructed by combining energy modules of moisture evaporation, heat recovery system, air heaters, supply air and exhaust air. Taking a corrugated paper machine as an example, ventilation system influence on the energy consumption of drying system is analyzed systematically. It is concluded that reducing the temperature of supply air and increasing exhaust humidity as much as possible to save energy consumption on the premise of meeting the safety production. The increase of supply air humidity will lead to the increase of steam consumption for heating supply air, power consumption of fans, and the total steam consumption in the drying process, so the intake point of supply air should be chosen at the point with low absolute humidity. The models can predict the energy consumption of ventilation system adjustment and optimization, and provide a method for energy-saving evaluation of ventilation system technical transformation in drying process.

Thermal and hydraulic characteristics of a parabolic trough collector based on an open natural circulation loop: The effect of fluctuations in solar irradiance

This study introduces a novel open natural circulation loop-based parabolic trough collector capable of operating in dual-mode and is tested experimentally for four days of solar insolation under three common climatic conditions. The tests are conducted in two modes viz hot water and low enthalpy steam generation. Both modes shows stable thermo-hydraulic characteristics with Start-up oscillations. Hot water mode experienced single mode thermal oscillations with 0.015 Hz having a decay ratio of 0.45. Steam generation mode experienced little fluctuation in outlet temperature with the insolation. However, it affects mass flux in both modes. Nevertheless, all fluctuations are stable and die out faster. Type-I instability is observed in two-phase flow transition in the receiver tube for both the modes. Overall efficiency is estimated at 68%, which is almost consistent throughout the day. The efficiency and total heat loss are also observed to be dependent on total insolation. In Hot water mode, the system can produce 150 L of hot water at 97.5 °C, and 8.7 kg of total steam in Steam generation mode. The results also show that proposed Parabolic Trough Collector based on Open natural Circulation loop is suitable for agricultural and small-scale industries where hot water or low-enthalpy steam at temperatures of 80–110 °C are required.

Novel design of lubricant-type vacuum distillation process for lube base oils production from hydrocracking tail oil

Dividing-wall columns (DWCs) are widely used in the separation of ternary mixtures, but rarely seen in the separation of petroleum fractions. This work develops two novel and energy-efficient designs of lubricant-type vacuum distillation process (LVDP) for the separation of hydroisomerization fractions (HIF) of a hydrocracking tail oil (HTO). First, the HTO hydroisomerization reaction is investigated in an experimental fixed-bed reactor to achieve the optimum liquid HIF by analyzing the impact of the operating conditions. A LVDP used for HIF separation is proposed and optimized. Subsequently, two thermal coupling intensified technologies, including side-stream (SC) and dividing-wall column (DWC), are combined with the LVDP to develop side-stream vacuum distillation process (SC-LVDP) and dividing-wall column vacuum distillation process (DWC-LVDP). The performance of LVDP, SC-LVDP, and DWC-LVDP are evaluated in terms of energy consumption, capital cost, total annual cost, product yields, and stripping steam consumption. The results demonstrates that the intensified processes, SC-LVDP and DWC-LVDP significantly decreases the energy consumption and capital cost compared with LVDP. DWC-LVDP further decreases in capital cost due to the removal of the side stripper and narrows the overlap between the third lube oils and fourth lube oils. This study attempts to combine DWC structure into the separation of petroleum fractions, and the proposed approach and the results presented provide an incentive for the industrial implementation of high-quality utilization of HTO through intensified LVDP.

ANALISA ALIRAN MASSA UAP PADA KATUP KONTROL UREA (UREA GLOBE CONTROL VALVE) DI UNIT PRODUKSI UREA PABRIK 1B PT. PETROKIMIA GRESIK

In a process, industrial plants have several tools that require steam to help run the processing of a material. For the heating process, PT. Petrokimia Gresik requires steam. Sometimes the steam leak during the process, which reduces the productivity of this industry. For that reason, the purpose of this calculation is to find out the steam loss during the process, especially in the urea globe control valve (PV-723, PV-726, PV-735). The result shows that the upstream pressure and temperature at PV-723 are 21 kg /cm2G and 307 oC, upstream pressure and temperature in PV-726 are 5 kg / cm2G and 158 oC, upstream pressure and temperature on PV-735 of 2.5 kg / cm2G and 138 oC. For downstream pressure on all valves is 1.03323 kg/cm2G. The obtained mass flow (F) in each valve is 0.514 tons / hr, 0.86 tons / hr and 1,902 tons / hr. The value of the input mass balance of steam in the system is 82.70 tons/hour and the overall output is74.11 tons/hour. Therefore, the total steam loss in PV-723, PV-726, and PV-735 is around 8.59 tons/hour which means there is some leak during the process that needs to do further investigation.

A Production Performance Model of the Cyclic Steam Stimulation Process in Multilayer Heavy Oil Reservoirs

Cyclic steam stimulation (CSS) is a typical enhanced oil recovery method for heavy oil reservoirs. In this paper, a new model for the productivity of a CSS well in multilayer heavy oil reservoirs is proposed. First, for the steam volume of each formation layer, it is proposed that the total steam injection volume will be split by the formation factor (Kh) for the commingled steam injection mode. Then, based on the equivalent flow resistance principle, the productivity model can be derived. In this model, the heavy oil reservoir is composed of a cold zone, a hot water zone, and a steam zone. Next, using the energy conservation law, the equivalent heating radius can be calculated with the consideration of the steam overlay. Simultaneously, a correlation between the threshold pressure gradient (TPG) and oil mobility is also applied for the productivity formula in the cold zone and the hot water zone. Afterward, this model is validated by comparing the simulation results with the results of an actual CNOOC CSS well. A good agreement is observed, and the relative error of the cumulative oil production is about 2.20%. The sensitivity analysis results indicate that the effect of the bottom hole pressure is the most significant, followed by the TPG, and the effect of the steam overlay is relatively slight. The formation factor can affect the splitting of the steam volume in each layer; thus, the oil production rate will be impacted. The proposed mathematical model in this paper provides an effective method for the prediction of preliminary productivity of a CSS well in a multilayer heavy oil reservoir.

Numerical analysis of environment-friendly solar aided coal-fired supercritical thermal power plant cycle integrated with dual heat exchangers

The hybrid solar-coal supercritical steam thermal system has been developed in current research work. The proposed system uses a double-tank heat storage system to increase the stability of the solar tower system, and two heat exchangers to transfer heat from molten salt in the solar tower system to steam in a supercritical coal-fired thermal system. TRNSYS software has been used as a platform to build a model of the solar coal-fired hybrid supercritical steam thermal system. Local weather data is imported to simulate the characteristic year’s operation of a hybrid system under design and off-design working conditions. The variation of heat transferred from solar system to supercritical steam thermal system, power generated from supercritical steam thermal system, solar-electrical generation capacity, efficiency and proportion of solar power generation are compared and analyzed. The results show that after the system is integrated, the tower solar steam production mechanism will increase the output power of supercritical steam thermal system and reduce thermal efficiency of the integrated system. When boiler steam flow rate is kept at less than reference flow rate after joining with solar steam flow rate, total steam flow rate exceeds the reference flow rate, while solar steam flow rate increases.

Steam and Pressure Management for the Conversion of Steelworks Arising Gases to H2 with CO2 Capture by Stepwise Technology

Steel production is a main source of CO2 emissions globally. These emissions must be drastically reduced to meet climate change mitigation goals. STEPWISE is a Sorption Enhanced Reactive Process (SERP) technology that converts steel works arising gases to H2 with simultaneous CO2 capture. The main energy requirements of the process are the high- and low-pressure steam quantities that are needed to rinse and regenerate the adsorbent. In this simulation study, the separation performance of STEPWISE is evaluated over a range of steam and feed pressure inputs by searching those design points where CO2 recovery and purity percentages are equalized. This method is used to facilitate the comparison of different operating regimes. Results highlight the importance of the rinse to purge ratio (R/P) as a design variable. A higher R/P ratio is demonstrated to maintain CO2 recovery and purity of ~95.5%, while total steam consumption and feed carbon loading are reduced by 27% and 20%, respectively. This is achieved without changing other parameters, like cycle time. Additionally, it is demonstrated that the CO2 capture performance can be maintained for varying feed pressure values by tuning the feed carbon loading. Future studies are recommended to focus on the expected role of the feed gas steam content on these findings.