H2 Concentration Research Articles

Prediction of Solvent Composition for Absorption-Based Acid Gas Removal Unit on Gas Sweetening Process.

The gas sweetening process is essential for removing harmful acid gases, such as hydrogen sulfide (H2S) and carbon dioxide (CO2), from natural gas before delivery to end-users. Consequently, chemical absorption-based acid gas removal units (AGRUs) are widely implemented due to their high efficiency and reliability. The most common solvent used in AGRU is monodiethanolamine (MDEA), often mixed with piperazine (PZ) as an additive to accelerate acid gas capture. The absorption performance, however, is significantly influenced by the solvent mixture composition. Despite this, solvent composition is often determined through trial and error in experiments or simulations, with limited studies focusing on predictive methods for optimizing solvent mixtures. Therefore, this paper aims to develop a predictive technique for determining optimal solvent compositions under varying sour gas conditions. An ensemble algorithm, Extreme Gradient Boosting (XGBoost), is selected to develop two predictive models. The first model predicts H2S and CO2 concentrations, while the second model predicts the MDEA and PZ compositions. The results demonstrate that XGBoost outperforms other algorithms in both models. It achieves R2 values above 0.99 in most scenarios, and the lowest RMSE and MAE values of less than 1, indicating robust and consistent predictions. The predicted acid gas concentrations and solvent compositions were further analyzed to study the effects of solvent composition on acid gas absorption across different scenarios. The proposed models offer valuable insights for optimizing solvent compositions to enhance AGRU performance in industrial applications.

Effect of process parameters on residual gas in metal package

The effect of process parameters on the residual gases, H2O, O2, CO2 and H2 in the metal package were investigated in this study. It was found that the H2O mainly came from the surface adsorption of raw materials and the H2 was from the electroplated Ni/Au layers of Kovar alloy. The O2 primarily came from the water vapor and the environment, while the CO2 in the cavity was mainly generated by the reaction between the O2 and residual carbon. The temperature and holding time of the baking, parallel seam welding and screening aging process could effectively affect the content of H2O, O2, H2 and CO2 in the cavity. Prior to sealing, increasing the temperature of baking and parallel seam welding could reduce the contents of H2O, O2 and H2. However, after sealing, the H2O and H2 absorbed on the material surfaces continued to desorb into the sealed cavity during the screening aging process, leading to the increase of the H2O and H2 content. It was also found that the gas leakage has an important effect on the residual gas inside the cavity. In the long-term screening aging process, the O2 could leak into the cavity from the air because of the concentration gradient. In the meantime, the O2 reacted with the residual carbon to generate CO2, causing an increase in the CO2 content. As the CO2 concentration in the cavity was higher than that in the air, it would leak into the air until equilibrium was reached.

In-situ and ex-situ selective catalysis of biochar-based catalysts for the production of high-quality bio-oil and H2-rich gas from tobacco stem

Optimizing the catalytic pyrolysis process is a promising approach to enhance the quality of the resulting products. Thus, four metals (Ni, Fe, Co, Cu) were loaded on biochar support to prepare biochar-based catalysts, and the mechanism of its effect on quality improvement of bio-oil and pyrolysis gas during in-situ and ex-situ pyrolysis of tobacco stem was investigated. The results showed that the biochar-based catalyst has high selectivity for H2-rich and phenols production during in-situ pyrolysis, while the phenols content reached 57.99 % and H2 content reached 49.91 % in Fe@BC group. It is highly selective to H2-rich and N-containing compounds during ex-situ pyrolysis, and the content of N-containing compounds reached 47.23 % and the content of H2 reached 47.59 % in the Ni@BC group. This contributes to the efficient use of high-quality bio-oils and the production of clean gases. Biochar-based catalysts hold significant potential for the pyrolysis industry, paving the way for large-scale production and application of high-quality pyrolysis products.

Roles of Prostaglandins and Hydrogen Sulfide in an Outflow Model of the Porcine Ocular Anterior Segment Ex Vivo

Background: Hydrogen sulfide (H2S)-releasing compounds can reduce intraocular pressure in normotensive rabbits by increasing aqueous humor (AH) outflow through the trabecular meshwork. In the present study, we investigated the contribution of endogenous H2S and the role of intramurally generated prostaglandins in the observed increase in AH outflow facility in an ex vivo porcine ocular anterior segment model. Material and Methods: Porcine ocular anterior segment explants were perfused with Dulbecco’s Modified Eagle’s Medium maintained at 37 °C and gassed with 5% CO2 and 95% air under an elevated pressure of 15 mmHg for four hours. Perfusates from the anterior segment explants were collected and immediately assayed for their H2S and prostaglandin E2 content. Results: Elevating perfusion pressure from 7.35 to 15 mm Hg significantly (p < 0.001) increased H2S concentration in the perfusate from 0.4 ± 0.1 to 67.6 ± 3.6 nM/µg protein. In the presence of an inhibitor of cystathionine ß-synthase/cystathionine γ-lyase, aminooxyacetic acid (AOAA, 30 µM), or an inhibitor of 3-mercaptopyruvate sulfurtransferase, α-ketobutyric acid (KBA, 1 mM), the effects of elevated pressure on H2S levels in the perfusate was significant (p < 0.001). Furthermore, flurbiprofen (30 µM) and indomethacin (10 µM) attenuated the elevated pressure-induced increase in H2S levels in the perfusate. Interestingly, elevating perfusion pressure had no significant effect on PGE2 concentrations in the perfusate. While the inhibition of H2S biosynthesis by AOAA or KBA did not affect PGE2 levels in perfusate, flurbiprofen (30 µM) caused a significant (p < 0.05) decrease in the concentration of PGE2 under conditions of elevated perfusion pressure. Conclusions: We conclude that the elevated perfusion pressure-induced increase in H2S concentrations depends upon the endogenous biosynthesis of H2S and intramurally produced prostaglandins in the porcine anterior segment explants. While the concentration of PGE2 in the perfusate under elevated perfusion pressure was unaffected by pretreatment with inhibitors of H2S biosynthesis, it was reduced in the presence of an inhibitor of cyclooxygenase.

A novel dialdehyde cellulose-based colorimetric and turn-on fluorescent probe for H2S detection and its application in red wine

Hydrogen sulfide (H2S) is considered one of the most important gaseous transmitters in the metabolic system, and the abnormal concentration of H2S is associated with a variety of diseases. Up to now, it is still a challenge to develop a portable assay for H2S even though the research about the detection of H2S is booming. Herein, a novel bifunctional dialdehyde-cellulose fluorescent probe DAC-DPD was prepared with high selectivity and sensitivity to H2S with colorimetric and fluorescent “turn-on” characteristics, and the limit of detection (LOD) of DAC-DPD for H2S was 0.831 μM. The sensing mechanism of DAC-DPD's to H2S was a Michael addition reaction confirmed by HRMS, 1H NMR and density-functional theory (DFT) calculations. DAC-DPD can be used to detect H2S in red wine samples. In Addition, the prepared DAC-DPD embedded fluorescent membrane can be used as a reliable sensing platform for rapid detection of H2S. It provided a convenient and rapid detection material, simplifying the detection process of H2S, which is of great significance for the development of cellulose-based fluorescent smart material.

Impedance-based multivariate analysis for accurate estimation of H2S concentrations using CuCrO2 gas sensor

This study unveils an innovative approach to fabricating H2S gas sensor prototypes for continuous monitoring, leveraging Pd-decorated CuCrO2-based metal oxide semiconductor (MOS) chemiresistors and artificial neural network-assisted impedance-based multivariate analysis. Sensors were exposed to H2S in cross-interfering environments containing humidity, NO2, NH3, CH4, H2, and CO2. Impedance-based parameters (Z, phase difference, Z′ and Z") obtained at various frequencies demonstrated that sensors were reproducible and selective for H2S detection. A neural network-based multilayer perceptron (MLP) regression model was trained with different impedance-based parameters to estimate the H2S concentrations. Continuous operation resulted in larger baseline variation for Z, Z′, and Z" readings; however, the measured phase difference values exhibited less depletion than other parameters. Furthermore, concerns about baseline changes were effectively addressed with a fine-tuned MLP model, which predicted both pure air and H2S atmospheres more correctly under cross-interfering and baseline-depleted conditions by employing phase differences at different frequencies as input. Possible reasons for the accurate prediction can be attributed to the confined behaviour of phase difference and discussed with the help of sensor statistical parameters such as mean variation, standard deviation and principal components.

Asynchronous changes of hydrogen sulfide and its generating enzymes in most tissues with the aging process.

Aging is an inevitable and irreversible biological process that gradually heightens the risks of various diseases and death. As a newly discovered endogenous gasotransmitter, hydrogen sulfide (H2S) has been identified to exert multiple beneficial impacts on the regulation of aging and age-related pathologies. This study was aimed at systematically exploring the relationship between asynchronous aging processes and H2S concentrations in various tissues of aging mice. Samples of plasma and 13 tissues were collected from four cross-sectional age groups (3, 6, 12 and 18 months of age) covering the lifespan of male C57BL/6J mice. The H2S concentration was quantified by a reported liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with monobromobimane derivatization. Additionally, the expressions of cystathionine γ-lyase (CSE), cystathionine β-synthase and 3-mercaptopyruvate sulfurtransferase, in those tissues were analyzed by Western blotting. We discovered that the H2S concentrations decreased asynchronously with the aging process in plasma, heart, liver, kidney, spleen, subcutaneous fat and brown fat and increased in brain and lung. At least one of the three H2S-generating enzymes expressions was compensatorily up-regulated with the aging process in most tissues, among which the up-regulation of CSE was the most prominent.

Process Modeling and Simulation of Sugarcane Bagasse Gasification using different Oxidizing Medium: A Universal Gasification Model

Biomass gasification is gaining significant interests among the researchers as the syngas/producer gas obtained from gasification of biomass can be versatile in usage. However, the outcome of gasification (gas composition/LHV/CGE) varies with the gasification medium employed. This article presents the process modeling of sugarcane bagasse gasification for three different gasifying media, namely air, steam and air-steam, using cycle tempo software to identify the best among different gasification processes for the considered response variables. A process model has been developed, and the gas composition predicted by the proposed model is validated with published experimental results for different biomass feeds. The influence of important operational parameters such as SBR, ER and gasification temperature on gas composition, LHV, and CGE were analyzed and compared for all three gasifying media. SBR, ER and gasification temperature have a very strong impact on the gas composition, LHV, and CGE. With the increase in SBR value, H2 concentration increases, whereas the concentration of CO decreases. The maximum concentration of H2 was observed to be 57.81 % at an SBR of 2 and at a gasification temperature of 750ºC for steam gasification. For air-steam gasification, optimum values of SBR and ER are observed to be 0.5 and 0.2, respectively, at a gasification temperature of 750ºC, where LHV (9.91 MJ/kg) and CGE (84.14%) were found to be maximum.

Effect of H[formula omitted] addition on NH[formula omitted] flame structure and dynamics in a mixing layer

Hydrogen addition has been widely used to improve the combustion performance of low-reactivity fuels such as NH3. In this study, a series of two-dimensional NH3/H2 flames in mixing layers were investigated numerically. The aim is to assess and interpret the effects of H2 addition on the structure and dynamics of ammonia flames. Detailed chemistry and transport models were considered in the simulations. It was shown that for pure hydrogen or ammonia flames, a classical tribrachial structure was observed. The non-premixed branch in the tribrachial flame of NH3 combustion features high heat release rate (HRR), while the two premixed branches are weak. The mixture fraction corresponding to the maximum HRR of NH3 combustion is significantly lower than the stoichiometric mixture fraction. When blending ammonia with hydrogen, a tetrabrachial flame structure consisting of two premixed branches and two non-premixed branches was observed, where one non-premixed branch corresponds to the reaction of NH3, while the other is formed due to the reaction of H2. It was suggested that the formation of the tetrabrachial flame is related to the preferential diffusion of hydrogen. After decreasing artificially the diffusivity of hydrogen to suppress the preferential diffusion effect, the flame exhibits only three branches with the merging of the two non-premixed branches. By analyzing the flame dynamics at the leading edge, it was found that the flame speed (Sd∗) is negatively correlated with the flame stretch (κ) and scalar dissipation rate (χ), with Sd∗ decreasing almost linearly with κ or χ, consistent with previous studies of methane and hydrogen flames. As the H2 concentration is increased, the values of Sd∗ increase due to the enhanced reactivity.

Hydrogen-Ignited-Methanol Catalytic Co-Combustion of Aromatic Volatile Organic Compounds over PdPt/Al2O3 Bimetallic Catalyst

Electric heating is frequently employed to treat volatile organic compounds (VOCs) through catalytic combustion. However, it is associated with problems such as slow heating, high energy consumption, and low efficiency. This study explores PdPt/Al2O3 catalysts for igniting methanol (MeOH) through H2 catalytic combustion, providing internal on-site heating of catalyst active sites. It also investigates VOCs’ abatement using H2-ignited-MeOH combustion without H2 and external heating. Bimetallic catalysts enhance activity and reduce thermal aging. Hydrogen gas (H2) can initiate the MeOH combustion at room temperature with the addition of very small amounts, even below its low explosive limit of 4%. This process optimizes MeOH ignition at approximately 350 °C, even when the concentration of H2 is as low as 0.01%. This method enhances combustion kinetics, converting MeOH and VOCs into CO2 and water. Catalytic performance is independent of PdPt nanoparticle sizes in fresh and spent catalysts, represented in XRD and STEM. Using hydrogen as an igniting agent provides a clean, effective method to initiate catalytic reactions, addressing traditional challenges and enhancing VOCs’ decomposition efficiency.

Use of carbon-encapsulated zero-valent iron nanoparticles from waste biomass to hydrogen sulphide wet removal.

This study evaluates the use of carbon-encapsulated zero-valent iron nanoparticles for biogas upgrading in wet systems. The nanoparticles were produced by hydrothermal carbonization, using olive mill waste (OMW) or microalgae as carbon sources. The solids were characterized to investigate the specific surface area, total and zero-valent iron content, pHPZC and chemical and crystalline composition. Their adsorption performance towards hydrogen sulphide (H2S) was tested by treating two types of synthetic biogas with and without CO2. In both cases, the starting H2S concentration was approximately 60 ppm and the experiments lasted until the complete saturation of the nanoparticles. Optimal Fe/C ratios of 0.05 for OMW nanoparticles and 0.2 for microalgae nanoparticles demonstrated H2S-specific adsorption capacities of 9.66 and 9.55 , respectively, in a synthetic biogas without CO2. The addition of CO2 in biogas reduced adsorption, possibly due to system acidification. X-ray photoelectron spectroscopy analysis revealed surface compounds on the surface of the spent nanoparticles, including disulphides, polysulphides and sulphate. The saturated adsorbents were effectively regenerated with air, leading to the oxidation of sulphur species and desorption. The regeneration allowed a total adsorption capacity of 53.25 and 34.14 , after 10 consecutive cycles of adsorption/regeneration with a single batch of olive mill and microalgae nanoparticles, respectively.

Ultraselective carbon hollow fiber membrane for H2 extraction from blended natural gas

Blending hydrogen into natural gas (H2NG) pipelines is a feasible solution for low-cost hydrogen delivery while purifying H2 at end-use remains challenging due to its high pressure and low H2 concentration. Herein, biomass-derived carbon hollow fiber membranes (CHFMs) with ultrahigh H2/CH4 separation factor of 4149.0 under a simulated H2NG (10 mol% H2/90 mol% CH4) at 30 bar were reported, and the separation performance maintained within 150 h in a dynamic durability test. Furthermore, the CHFMs showed good stability under fluctuating temperature feeds (up to 100 °C). To evaluate the feasibility of the CHFMs for H2 extraction from H2NG, a three-stage membrane system was designed based on the mixed gas separation performances. It suggested that 99.99 mol% H2 can be achieved with a 90 % recovery, and the specific H2 purification cost was 0.245 $/Nm3 for a 1.8 × 105 Nm3/h production scale, which provides the possibility of hydrogen extraction from H2NG pipelines.

Long-term carrier lifetime instabilities in n-type FZ- and Cz-silicon under illumination at elevated temperature

Even though n-type Si wafers show a lower extent of light-induced degradation, similar degradation and regeneration behavior as in p-type Si materials has been observed for various n-type Si monocrystalline materials. In this work, the long-term behavior of minority charge carrier lifetime in non-diffused n-type FZ-Si and Cz-Si wafers during illumination at elevated temperatures is investigated. Thereby, various influencing factors such as peak firing temperature and treatment temperature are considered. Degradation and a very strong regeneration effect, which exceeds the initial effective lifetime value, can be observed in the samples. Since surface-related saturation current density remains almost constant during degradation and regeneration, the effect seems to be bulk related. The extent of degradation and regeneration could be shown to be firing temperature-dependent. It could also be shown for n-type FZ-Si wafers that higher firing temperatures result in an increased H2 content within the silicon bulk. Investigations of the injection-dependent defect density revealed that the defect formed during degradation is not a deep level Shockley-Read-Hall defect. Observations at different treatment temperatures and constant illumination of 0.9(1) sun photon flux equivalent have shown that a higher treatment temperature leads to faster degradation and regeneration kinetics. Similarly, higher injection rates also speed up regeneration kinetics. Since degradation also occurs in darkness, the bulk related degradation effect in n-type FZ-Si is charge carrier-induced and not necessarily light-induced.

Efficiency, characterization, and kinetics during removal of COS and H2S in gasified syngas by red soil

Application of red soil in dry desulfurization process for removal of H2S and COS from coal gasified gas is preferable due to its metal oxides content, sustainability, and low cost. This study examined the performance of several red soil types around Taiwan, including Loupi/LP, Houdi/HD, and Dadusan/DDS for removal of COS and H2S. LP red soil presented the best removal efficiency with 91.8 % utilization value and chosen in further assessment on the performance under various operating conditions and cycle test. Moreover, this study was also aimed to explore the type of active metal oxides for removal of COS and H2S, along with the reaction kinetics and exhausted gas analysis after the process. The presence of iron oxides in LP red soil beneficially supported the removal of COS and H2S. Moreover, increasing of CO content in the syngas prolonged the breakthrough time and utilization value. On the other side, higher H2 content triggered the occurrence of water–gas-shift reaction. The cycle test indicated sintering process due to intense reaction under high temperature which led to deterioration of performance. Analysis of reaction kinetics using both Type I and Type II deactivation models indicated their well fitting data with the data of this study.

2D electrodeposition assembly of Cu/Cu2O nanoarrays for low temperature H2S sensing

Ultra-sensitive hydrogen sulfide (H2S) detection technology at low temperatures provides critical support for the application of one-time alert systems under extreme conditions, ensuring reliable monitoring of H2S in low-temperature environments and enhancing safety and practicability. In this study, we developed a novel low-temperature H2S sensor based on Cu/Cu2O nanoarrays, prepared through a combination of 2D electrodeposition in situ assembly and the hydrothermal method. The heterointerface between Cu nanowires and Cu2O nanocubes presents a high barrier, which can be modulated to zero through the formation of continuous CuxS conductive channels via the vulcanization reaction, thereby achieving excellent sensitivity and selectivity towards H2S at low temperatures. At freezing temperatures and low H2S concentrations (≤20 ppm), the sensors show ideal recovery and reasonable sensitivity (R=150 to 10 ppm H2S at 0 °C). However, the response significantly increases (R=5624 at 10 ppm H2S at 50 °C) and recovery is lost under reversed conditions. First-principles calculations have confirmed that the enhanced H2S adsorption at the heterointerface is the primary reason for the robust response observed at 0 °C. Experimental results demonstrate that the Cu/Cu2O nanoarrays were capable of rapid detection of H2S at low temperatures through modulation of heterointerface barriers.

Flexible hybrid nanostructured chemiresistive sensing platform for low-temperature trace hydrogen detection

The prevalence of hydrogen (H2) utilization across commercial and industrial sectors has spurred the innovation of various H2 gas sensors. However, their practical implementation has been hindered by issues such as cost inefficiency, low sensitivity, inadequate selectivity, and limitations in low-temperature sensing capabilities. Consequently, the development of a sensor capable of surmounting these challenges is paramount for widespread adoption. In this study, a cost-effective approach has been used to fabricate a flexible hybrid nanostructured platform on polyethylene terephthalate (PET) substrate incorporating a combination of zinc oxide (ZnO), titanium oxide (TiO2), and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). This platform has undergone meticulous morphological characterization and comprehensive evaluation for H2 gas sensing applications at both room temperature and 50˚C. The results reveal that the developed PEDOT:PSS/TiO2/ZnO NWs sensor exhibits superior H2 gas sensing characteristics with 141 % and 163 % higher response by proportions at 100 ppb and 100 ppm, respectively outperforming other prepared devices in the same environment. Thus demonstrating exceptional sensitivity of 0.448 %/ppm with three cycle repeatability, H2 selectivity and nine months of stability at low temperatures. Moreover, the sensor has an ultralow limit of detection (LOD) of ∼9 ppt, along with a rapid response time of 65 s and a recovery time of 42 s at an H2 concentration of 100 ppb. This research drives the advancement of efficient, rapid-responsive, and discerning trace detection of H2 gas at low temperatures.

Enhancement effect of semicoke waste heat on energy conservation and hydrogen production from biomass gasification

Key approaches to alleviating global warming and curbing fossil fuel depletion involve various industrial energy-conservation technologies and carbon dioxide (CO2) emission reduction methods. The production of hydrogen (H2)-rich gas from inexpensive and readily available biomass, as an alternative energy source, is becoming increasingly promising. However, this application faces challenges such as high energy consumption and low gas quality. In this study, the waste heat released by semicoke production from lignite gasification and CO2 from exhaust gas were utilized to gasify biomass. This approach aims to save energy in biomass gasification and use CO2 in exhaust gas to improve the H2 content in biogas. A simulation was conducted to recover semicoke waste heat by combining a suspension tube with CO2 flow to generate steam and high-temperature CO2, which were then simultaneously sent into a gasifier to produce H2 through biomass gasification. The results revealed that the rate of semicoke waste heat recovery exceeded 90 %. The yield of steam and the rate of waste heat recovery improved with increasing mass flow rate of semicoke and then slightly decreased with increasing steam pressure and CO2 mass flow rate. The yield of H2 increased with the semicoke mass flow rate and steam pressure. The rate of energy conservation ranged from 15 % to 239 %, peaking at a CO2 mass flow rate of 0.09 kg/s. Compared with the case without waste heat recovery, the economic benefits increased from 12 to 28 times.

Equilibrium modelling of steam gasification of PKS system and CO2 sorption using CaO: A digitalized parametric and techno-economic analysis

The conversion of palm oil waste into energy can complement the energy mix with renewable energy and bring economic benefits to the palm oil industry. A process simulation model for palm kernel shell (PKS) steam gasification for H2-enriched syngas with the integration of CO2 capturing using CaO has been investigated using Aspen Plus V10®. Techno-economic and energy analyses have also been conducted to identify energy-saving opportunities for commercialization. The effect of process variables, including reactor temperature (600–800 °C), Steam/PKS ratio (0.5–2 wt/wt), and CaO/PKS ratio (0–1.5 wt/wt), have been determined, with the predicted results compared to the reported experimental data. H2 concentration has been increased with 76–78 vol% with the temperature elevation from 650 to 750 °C. Additionally, a substantial increase in H2 content from 68 to 72vol% was observed when the steam flow rate was increased from 0.5 to 1.5. Conversely, the CO2 concentration decreased from 25 to 8vol% as the adsorbent ratio was raised from 0.5 to 1.5. The techno-economic analysis showed that the capital investment is $4.11 million, and the operating cost is $3.89 million per year, which is also very high due to the high raw material costs. In the case of energy, saving that 3.03 and 1.513 Gcal/hr can be saved in terms of utilities and gas cooling that economized the process which shows that utilization of these in heat exchange networks can significantly reduce costs, with up to 78 % savings in heat exchanger capital and 35 % in total energy consumption. The energy potential could be harnessed through the digitalization of the process.

A novel wide flow matching approach of hydrogen-powered F-class gas turbine based on multistage installation angle

To achieve excellent power performance of F-class gas turbine when using pure H2 or H2-rich fuel, this work develops a novel and flexible flow matching approach by modifying the turbine multistage installation angle, with obvious features of easy implementation and low cost. An accurate thermodynamic model of heavy-duty gas turbine considering turbine-stage cooling is established and verified by the actual operation data from Ban-Shan power plant, and to investigate variable condition property and emission characteristic of gas turbine with natural gas and H2-rich fuel. Faced with the inefficiency and narrow working area caused by the flow mismatch between 18-stage compressor and 3-stage turbine when natural gas is switched to H2-rich fuel, the scheme of modifying the installation angles of multistage rotary blade and static blade is proposed. By calculating the pressure and temperature at each turbine stage, the gas turbine power, efficiency, Mach number and NOx emission with different H2 concentration are predicted. Results show that, as the H2 concentration increases, the fuel volume flow required to reach the same turbine inlet temperature increases.When H2-rich fuel increases the turbine inlet volume flow by 3.23 %, the cooling effect significantly decreases, and the turbine outlet temperature rises by about 13.60 K, which deviates from the appropriate operating point. The most serious is the phenomenon of over Mach number and airflow blocking at the outlet of the 2-stage and 3-stage turbine static blades. The installation angle variation increases with the increase of H2, and the higher the stage, the bigger the angle change. The gas turbine can be realized the wide flow matching feature corresponding to the installation angle variation of 0.19°/-0.41°, 0.38°/-0.48°, and 0.53°/-0.94°, respectively for all stages static/rotary blades. After re-matching, the maximum fluctuation of rated power and efficiency are 1.5 % and 1.7 %, and the NOx emission will reach the maximum value of 14.3 ppm with 70 % H2. Research work will provide a novel and feasible retrofit scheme for the heavy-duty gas turbine using clean and low-carbon fuel to widen flow matching scenario.

Novel experimental method to simulate reduction behaviour of burden in blast furnace shaft

In order to evaluate the effects of CO and H2 for the gas–solid reaction behaviour of the ferrous burden and coke in blast furnace shaft, a near-steady-state simulation test method of the blast furnace shaft was designed. The reduction behaviour of the ferrous burden, carbon solution loss reaction under different temperatures and atmospheres, and the effect of hydrogen enrichment on the CO gas utilisation ratio were investigated. The results show that above 830 °C, the reduction degrees of different ferrous burden structures under H2 atmosphere are higher than that under CO atmosphere. Better reduction degradation behaviour could be obtained under the hydrogen-rich atmosphere. The H2O generated under H2 atmosphere could promote the carbon solution loss reaction. The solution loss ratio reaching the maximum at 950 °C. Under hydrogen-rich atmosphere, CO gas utilisation ratio increased with the increased H2 concentration due to the effects of the products H2O and CO2.