Furnace Gas Research Articles

Application of multi-stage dynamic magnetizing roasting technology on the utilization of cryptocrystalline oolitic hematite: A review

A large number of studies have shown that oolitic hematite is an iron ore that is extremely difficult to utilize because of its fine disseminated particle size, high harmful impurity content and oolitic structure. To recover iron from oolitic hematite, we developed a novel multistage dynamic magnetizing roasting technology. Compared with traditional magnetizing roasting technologies, this novel technology has the following advantages: firstly, the oolitic hematite is dynamically reduced in a multi-stage roasting furnace, which shortens the reduction time and avoids ringing and over-reduction; secondly, the novel dynamic magnetizing roasting technology has strong raw material adaptability, and the size range of raw materials can be as wide as 0–15 mm; thirdly, the roasting furnace adopts a preheating-heating process, and the low-calorific value blast furnace gas can be used as the fuel and reductant, which greatly reduces the cost. The actual industrial production data showed that the energy consumption in the roasting process can be less than 35 kg of standard coal per ton of raw ore. The iron grade of the concentrate and iron recovery reached 65% and 90%, respectively.

Promoting effect of Fe/La loading on γ-Al2O3 catalyst for hydrolysis of carbonyl sulfur.

Catalytic hydrolysis of carbonyl sulfur (COS) from blast furnace gas is one of the keys to achieving ultra-low emission in the iron-steel industry. To improve the COS hydrolysis activity on γ-Al2O3 catalyst at low temperature, catalysts with Fe or La as the active component were prepared by the impregnation method, the physical and chemical properties of the catalyst were characterized by ICP, XRF, XRD, BET, and TPD. The hydrolysis activity of COS and sulfur resistance ability on various catalysts were investigated in a fixed bed reactor combined with gas chromatography. The results show that the addition of Fe or La improves the COS hydrolysis activity due to the increase in alkaline sites on the catalyst surface. The roles of various alkaline sites on catalysts have been recognized. The weak alkaline center is the reaction site of COS hydrolysis, the middle and strong alkaline centers are the adsorption and oxidation sites of H2S. The Fe/Al2O3 catalyst has higher hydrolytic activity and oxidative capacity for H2S removal due to forming more sulfate species on Fe. The La/Al2O3 catalyst has higher hydrolysis efficiency in that H2S rapidly desorbs from the catalyst surface to the gas phase, and then, the activity of reaction sites is recovered. This provides an idea for the preparation of sulfur-resistant catalysts.

Study of aluminosilicate refractories after operation in the presence of fluorine-containing wastes

Samples of aluminosilicate refractory after operation in the shaft and in the hearth of a coke-gas cupola were investigated; this cupola was used for smelting of cast iron with spheroidal graphite using carbon wastes from aluminium electrolysis production as a reducing agent. Use of only fluorine-containing carbon wastes as a solid fuel in cast iron production allows to utilize hazardous man-caused wastes, improves the economic performance of production and has influence on resistance of fireclay refractories. It was established that the products acquire a distinct zone features during the service, due to penetration of the components of gas and liquid phases and the effect of low-boiling components of carbon-containing wastes. Upon that, changes in the structure along the distance from the working space are complex ones in lining thickness and in concentration of volatile components in the “cold” parts of the lining. Permanent character of the mullite content in different zones of fireclay products can be traced, as well as a slight increase in the less altered zone, despite the different service conditions. Absence of alkaline and fluoride phases in the zones of refractory products in the pores and structure of the fireclay refractory was established, due to migration of these gaseous phases into the working space of the cupola with their subsequent removal with furnace gases. Additional development of mullite in certain zones of refractory was revealed, resulting by its synthesis from alumina that did not react during fireclay refractories manufacture under the mineralizing action of a fluorine compound. Use of fluorine-containing carbonaceous wastes as a solid fuel in cast iron production makes it possible to utilize hazardous man-caused wastes, improves the economic performance of production and has slight effect on resistance of aluminosilicate refractories in the conditions of a coke-gas cupola.

Air Quality Assessment of Industrial BoilersExhaust and its Impact Upon Workers’ Health

Air pollution is a major concern worldwide with human activities being the main contributor and causing serious health impacts. The present study was designed to monitor the amount of gaseous pollutants (CO2, CO, SO2, NOX) and total suspended particulates (TSP) from different industrial boiler’s exhaust using three fuel types (coal, natural gas and heavy furnace oil/diesel). These five parameters were measured and compared with the National Environmental Quality Standards (NEQS) of Pakistan. Coal and diesel boilers were emitting more SO2 (22x) as compared to natural gas. The natural gas boilers were producing more CO (7x) due to inefficient combustion and low mixing of air into gaseous fuel. The concentration of NOx from all boiler types were within the standard value. TSP values ranged from 82.3 mg m-3 to 245.7 mg m-3, which were within the NEQS limits due to the presence of control devices. Workers’ health (n=42) was assessed using a questionnaire and health of many workers was found to be compromised (34 %), while most of them were either unaware or were not provided PPEs (37.5%). Consequently, the workers were being exposed to large amounts of hazardous emissions in the industry.

Economic Evaluation of Renewable Hydrogen Integration into Steelworks for the Production of Methanol and Methane

This work investigates the cost-efficient integration of renewable hydrogen into steelworks for the production of methane and methanol as an efficient way to decarbonize the steel industry. Three case studies that utilize a mixture of steelworks off-gases (blast furnace gas, coke oven gas, and basic oxygen furnace gas), which differ on the amount of used off-gases as well as on the end product (methane and/or methanol), are analyzed and evaluated in terms of their economic performance. The most influential cost factors are identified and sensitivity analyses are conducted for different operating and economic parameters. Renewable hydrogen produced by PEM electrolysis is the most expensive component in this scheme and responsible for over 80% of the total costs. Progress in the hydrogen economy (lower electrolyzer capital costs, improved electrolyzer efficiency, and lower electricity prices) is necessary to establish this technology in the future.

FEATURES OF THE APPLICATION OF HEAT STORAGE ELEMENTS WITH A PHASE TRANSITION IN THE REGENERATIVE HEAT EXCHANGERS OF GLASS FURNACES

Increasing the air temperature in regenerative heat exchangers is one of the most effective means of increasing the efficiency of glass furnaces and reducing their fuel consumption. The value of losses with flue gases in furnaces remains quite high and amounts to 25–40 %. As a result, the question arises in the modernization of flue gas utilizers of glass furnaces, the purpose of which is to increase the amount of heat extracted from flue gases without a significant change in overall dimensions, as well as the aerodynamic characteristics of heat exchangers. One such measure is the use of heat storage elements with a phase change in the packing of regenerators. A feature of such materials is the presence of «residual» heat of the phase transition, i.e., such a packing will receive and transfer more heat by this amount compared to the traditional one. However, when solving this problem, the question arises of choosing a fusible material that satisfies the operating conditions of the packing of regenerative heat exchangers of glass furnaces. The paper analyzes the thermophysical properties of some inorganic substances, the characteristics of which make it possible to use them as a fusible material for packing elements. However, at the moment, inorganic compounds of barium sulfate BaSO4 and sodium sulfate Na2SO4 in combination with magnesite and periclase refractories have acquired practical use for high-temperature installations (regenerative heat exchangers of blast-furnace metallurgical production). Such materials have shown good thermal stability and stability under thermal cycling. The study of the possibility of using materials with a phase transition for heat storage elements of packings is associated with the need for mathematical modeling of complex heat exchange processes in the working space of regenerative heat exchangers under conditions of a quasi-stationary mode of their operation. Therefore, the final conclusions about the effectiveness of the modernization of regenerative heat exchangers by using packing with a phase change can only be made based on the results of additional studies, which will determine the influence of a whole complex of various factors that affect the performance of heat storage elements of this design.

Optimization on annual energy efficiency of heat pumps based on maximum solving of definition functions with multi constraints

Air conditioners is expected to be the second largest source of growth in global electricity demand. To promote electrification, heat pump air conditioner is encouraged to replace natural gas furnace. Improving heat pump’s energy efficiency can help reduce global energy consumption and greenhouse gas emissions. Annual performance factor is one of the key metrics to evaluate heat pump systems’ energy performance. Seeking annual performance factor maximum belongs to an optimization problem with multi constraints. However, due to the nested variables, continuous non-differentiable and piecewise form of annual performance factor definition functions, the optimized objective function is usually based on the simplification with large errors. Meanwhile, the multi constraint boundaries are either ignored or considered but through complicated and high-cost tests. In this research, the variable iteration logic of the annual performance factor definition functions is sorted firstly. Then the above exact mathematical definitions are programmed as the objective functions without any simplification. Enumeration method is used to establish the annual performance factor maximum solution algorithm. More importantly, taking a 3.5 kW cooling capacity mini-split heat pump prototype as an example, energy performance tests are conducted to fit the multi constraints, namely using less global parameters to cover more local parameters, which greatly simplifies the test procedures and cost. Then, using our proposed method, the maximum annual performance factor is predicted and validated by experiments. The prediction accuracy is 99.6%, with a 38.4% improvement compared to the best reported value from literature. Based on the recommended variable values, the prototype’s annual performance factor achieves the maximum with a 7.71% improvement from the baseline. The proposed method can save time and experimental resources in the product development stage compared with the traditional trial and error method.

Numerical Simulation Study of Gas-Solid Heat Transfer and Decomposition Processes of Limestone Calcined with Blast Furnace Gas in a Parallel Flow Regenerative Lime Kiln.

Quicklime is an essential reducing agent in the steel smelting process and its calcination from limestone is accompanied by considerable energy consumption. As a relatively economical lime kiln, the Parallel Flow Regenerative (PFR) lime kiln is used as the main equipment for the production of quicklime by various steel industries. PFR lime kilns generally use natural gas as the fuel gas. Although natural gas has a high calorific value and is effective in calcination, with the increasing price of natural gas and the pressure saves energy and protect the environment, it makes sense of exploring the use of cleaner energy sources or other sub-products as fuel gas. The use of blast furnace gas (BFG) as a low calorific value fuel gas produced in the steel smelting process has been of interest. This paper therefore develops a set of mathematical models for gas-solid heat transfer and limestone decomposition based on a Porous Medium Model (PMM) and a Shrinking Core Model (SCM) to numerically simulate a PFR lime kiln using BFG in order to investigate the feasibility of calcining limestone with low calorific fuel gas and to provide a valuable reference for future development of such processes and the kiln structure improvement.

The investigation of the role of nitrogen in the improvement of catalytic activity and stability of Zr/Ti-based material for carbon disulfide hydrolysis

A nonmetallic N-doped Zr/Ti-based catalyst was prepared to investigate the effect of N addition on catalytic performance for carbon disulfide (CS2) hydrolysis. The characterization of the catalyst indicated that doped N atoms were present as interstitial N in the TiO2 lattice, resulting in an increase in the number of basic sites of the catalyst from 1.64 to 2.37 and from 0.68 to 2.53 for weakly basic and strongly basic sites, respectively. In addition, the doping of N promoted the formation of OH groups, which were favorable for the hydrolysis of CS2, from water (H2O) adsorbed on the catalyst, thus greatly improving the performance of catalytic CS2 hydrolysis. However, N doping reduced the amount of chemisorbed oxygen on the catalyst surface from 44.7% to 33.4%, thus decreasing the oxidation reaction of the hydrolysis product H2S and improving the stability of the catalyst. CS2 hydrolysis reaction activity and catalyst lifetime were tested. The experimental results demonstrated that the catalytic CS2 hydrolysis performance was greatly improved after N doping, and the temperature to obtain 100% conversion was reduced from 180 °C to 130 °C. Selectivity to H2S was greatly improved with N-doped catalysts. Furthermore, the resistance of the catalyst to sulfate was improved. Nonmetallic N-doped Zr/Ti-based catalysts offer a new strategy for blast furnace gas desulfurization.

Enhanced removal of COS from blast furnace gas via catalytic hydrolysis over Al2O3-based catalysts: Insight into the role of alkali metal hydroxide

As blast furnace gas (BFG) can cause air pollution, it is an effective route to convert BFG into a kind of energy. However, it is important to remove carbonyl sulfide (COS) from BFG before burning it. This can be done with catalytic hydrolysis which is considered as a high-efficient technology. In this work, a series of catalysts are prepared via impregnation method to remove COS, in which aluminum oxide (Al2O3) and alkali metal hydroxide (MOH, M = Li, Na and K) are used as base and active component, respectively. Compared with other prepared catalysts, Al2O3 modified with 10% KOH has better catalytic performance in removing COS. The characterization results imply that alkali metal plays a significant role in the enhancement of COS removal efficiency. The capacity of catalysts to adsorb COS is significantly improved with the modification of alkali metal. Moreover, few carbonate or bicarbonate species can be found on the surface of the catalyst during COS hydrolysis. Furthermore, the catalytic mechanism and degradation route of COS hydrolysis on Al2O3 modified with 10% KOH are explored.

Numerical investigation of blast furnace gas and coke oven gas combustion under different O2/CO2 environments

AbstractA numerical model of a 75 t/h gas‐fired boiler burning blast furnace gas (BFG) and coke oven gas (COG) was developed to study the effect of O2/CO2 conditions on the combustion characteristics, verified by comparing with the results measured in field experiments. The results showed that the ignition distance of COG was shorter than that of BFG, and COG reached the stable combustion temperature of 1000 K earlier in the condition of O2/CO2 combustion with 31% O2 than in the condition of air combustion. Under different O2/CO2 conditions, the overall temperature of gas‐fired boiler decreased. The maximum temperature of air combustion, O2/CO2 combustion with 26% O2, and O2/CO2 combustion with 31% O2 were 1867, 1678, and 1834 K, respectively. Under the condition of O2/CO2 combustion, the radiation heat transfer of mixed gas was enhanced, and the overall heat flux was obviously improved. Under the O2/CO2 condition, the overall temperature was lower than that of air combustion, but the wall heat flux increased. The NOx production decreased after the change to O2/CO2 combustion, and the NOx generation at the furnace arch decreased from 70.28 mg/m3 to 6.94 mg/m3 under the condition of O2/CO2 combustion with 26% O2. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Experimental Validation of Methanol Synthesis from Steel Mill Gases Using a Miniplant Setup

AbstractUtilization of the gas streams generated by the iron‐ and steel‐making industry for the synthesis of synthetic fuels or chemicals is a promising way to kickstart a technical carbon cycle. Methanol synthesis from cleaned blast furnace gas is a challenge for process design and operation due to high inert gas contents and fluctuations in the gas supply. In this work, a miniplant setup with an adiabatic quench bed reactor was operated with cleaned blast furnace gas over a wide range of process conditions. The experimental data obtained were used to validate a simulation model of the miniplant setup with the perspective for an optimization of the process operational parameters. A high agreement between experimental and simulation data could be obtained, validating the applicability of the simulation approach presented in this work.

Pore space of steatite ceramics triggered by the allowance of natural fibers: High-resolution X-ray microscopy analysis and related thermo-mechanical properties

A large number (greater than 150) of porous steatite ceramic rods were prepared using different types of renewable plant fiber products as pore-forming agent with mass contents ranging from 2 to 10%. In addition, dense steatite ceramics were synthesized for comparison within a gas furnace at sintering temperatures between 1300 and 1350 °C. High-resolution 3D X-ray microscopy facilitated a non-destructive, direct investigation of the three-dimensional pore space and microstructure. By using image-based pore space analysis, various pore space parameters, such as, e.g., pore volume, pore-size distribution, and pore connectivity were determined. In addition to the characterization of the pore space, phase analysis, structural and chemical investigations were carried out by X-ray powder diffraction, electron microscopy, Fourier-transform infrared, Raman and X-ray spectroscopy. Finally, to evaluate the influence of characteristics on the physical properties, elastic, strength and thermal properties were determined. With the increase of porosity, the flexural strength and thermal conductivity values decrease from σf = 123 ± 8 to 37 ± 5 MPa and λ = 3.22 ± 0.02 to 1.77 ± 0.02 W/(m·K), respectively. The obtained experimental results were discussed by means of micromechanical models, highlighting the effect of pore-space morphologies on the physical performance of porous steatite ceramics.

Structural emissions reduction of China's power and heating industry under the goal of “double carbon”: A perspective from input-output analysis

Since the Chinese government put forward the "double carbon" target in 2020, emissions reduction has become the focus of the Chinese government's work. China's power and heating sector account for about 50% of China's total energy utilization. Therefore, implementing carbon emissions (CO 2 e) reduction in China's heat and power industries is an important part of China's goal to achieve "double carbon". Commencing the viewpoint of input-output investigation, the current paper uses the extended form of the input-output method, structural decomposition method, and energy utilization approach to examine the structural emission diminution of China's power and heating industry from 2007 to 2015. The outcomes show that initially from the investigation of structural aspects affecting CO 2 e of power and heating energy at the same time as the energy intensity, input, and energy composition influence played a critical function in minimizing CO 2 e in China's power and heating sector with this emission reduction effect viewing an increasing trend. Among them, the input composition influence was the key pollution diminution aspect of electric heating energy; second was the energy intensity influence, and the energy structure influence was the weakest. Second, the ultimate demand consequence was the core pouring aspect for the power and heating energy-allied growth CO 2 e with this driving effect displaying an increasing trend over time. Third, in the perspective of the supply side energy system analysis, less carbon power for instance coke oven gas, converter gas, blast furnace gas, and natural gas generally had emission reduction effect, except for raw coal, crude oil, diesel, fuel oil, and washing firewood and other high carbon energy had no obvious emission reduction effect. The research findings of the current study can provide a hypothetical analysis basis for the power heating industry to control the growth of CO 2 e from the viewpoint of input and output, and also provide an accurate path for the electric heating industry to more precisely decrease emissions from the supply side energy varieties.

Experimental study of gliding arc plasma-assisted combustion in a blast furnace gas fuel model combustor: Flame structures, extinction limits and combustion stability

As an essential by-product of the iron and steel enterprises, blast furnace gas fuel is used as an alternative fuel for gas turbine combustion to increase economic effect. However, the less combustible components and low heat value of BFG fuel make the combustion in combustor very challenging. In this paper, a gliding arc plasma was employed to assist the blast furnace gas /air combustion with different equivalence ratio. Flame chemiluminescence, the pressure and heat release rate pulsation were recorded simultaneously for showing the flame characteristics of blast furnace gas. The experimental result demonstrates that there are six flame structures in the combustion process of blast furnace gas fuel: A stable flame with short U-shaped (SS-Flame), a vertical oscillating flame (VO-Flame), a stable flame with long U-shaped (SL-Flame), a special gourd-shaped flame (SG-Flame), a lifted flame (L-Flame) and a continuous extinct flame (CE-Flame). According to characteristics of flame structures before flameout, all cases can be divided into three types of extinction modes: I: Direct extinction, II: Oscillation extinction, III: Lifted extinction. The equivalence ratio of extinction limits at the low volume flow rate of air is more likely to be extended by gliding arc plasma than those at the high volume flow rate of air. The pressure and heat release rate pulsation experiment result shows that the violent oscillation of the heat release can be one of the prediction indexes of the flameout of blast furnace gas fuel. In all cases, the pressure pulsation of blast furnace gas fuel combustion is ± 10 Pa, and there is no obvious dominant frequency of heat release pulsation. The amplitude of heat release rate decreases from 0.04 V to 0.01 V with gliding arc plasma addition at φ = 0.7 (E-1 case). Meanwhile, the flame structure of blast furnace gas fuel changes from VO-Flame to SS- Flame due to the gliding arc anchoring the flame root.

Experimental study on direct ignition of blast furnace gas by plasma igniter in a gas turbine combustor

Direct ignition of a gas turbine combustor using blast furnace gas fuel has become a critical issue at present. As an alternative technology of traditional spark plug ignition, plasma-assisted ignition has excellent performance in the gas turbine combustor. In this paper, the ignition system is designed to conduct a direct ignition experiment using the plasma and spark plug igniter. Then, the plasma jet characteristics, ignition limit, and flame propagation of the blast furnace gas combustor are analyzed. The results show that, using blast furnace gas fuel in the gas turbine combustor, the direct ignition of spark plug igniter fails and direct ignition of the plasma igniter succeeds. The jet from the plasma igniter is conical with a length of 30 mm and a diameter of 8 mm, which contains various active species (O、, O*、, O+、, O2+、, N2*, and, N2+). With the increase of air flow rate in the combustor, the equivalence ratio of plasma ignition limit increases from 0.7 to 0.83, and the time required for successful ignition increases from 860 ms to 4300 ms. Meanwhile, the flame propagates from a unidirectional mode to a bidirectional mode in the combustor. The laminar flame characteristics and ignition delay time of BFG/air mixtures were investigated by CHEMKIN package using the Gri-Mech 3.0 model. The active species in the plasma jet can shorten the ignition delay time from 1E-4s to 1E-5s and improve the laminar burning velocities from 7.58 cm/s to 10.90 cm/s. A large-scale initial flame kernel with concentrated energy is formed rapidly so that the flame can successfully propagate to the recirculation zone and burn stably. Finally, the blast furnace gas fuel was successfully ignited directly by the plasma igniter.

Role of Eu2+ and Dy3+ Concentration in the Persistent Luminescence of Sr2MgSi2O7 Glass-Ceramics.

In this study, glass-ceramics based on Sr2MgSi2O7 phosphor co-doped with Eu/Dy were obtained from the sintering and crystallisation of glass powders. The glasses were melted in a gas furnace to simulate an industrial process, and the dopant concentration was varied to optimise the luminescence persistence times. The doped parent glasses showed red emission under UV light excitation due to the doping of Eu3+ ions, while the corresponding glass-ceramics showed persistent blue emission corresponding to the presence of Eu2+ in the crystalline environment. The dopant concentration had a strong impact on the sintering/crystallisation kinetics affecting the final glass-ceramic microstructure. The microstructures and morphology of the crystals responsible for the blue emission were observed by scanning electron microscopy–cathodoluminescence. The composition of the crystallised phases and the distribution of rare-earth (RE) ions in the crystals and in the residual glassy phase were determined by X-ray diffraction and energy dispersive X-ray analysis. The emission and persistence of phosphorescence were studied by photoluminescence.

Inhibition effect of naphthalene on V2O5-WO3/TiO2 catalysts for low-temperature NH3-SCR of NOx

Coal tar in the glass furnace flue gas can poison the V2O5-WO3/TiO2 (VWTi) catalyst used for ammonia selective catalytic reduction (NH3-SCR) of NOx. Herein, naphthalene (Nap), as one of the main components of coal tar, was selected to investigate the poisoning effect of coal tar on VWTi catalyst in the range of 200–280 ℃. The experimental results showed that the activity of VWTi catalyst decreased sharply with the introduction of Nap vapor, and the NOx conversion was less than 20% after the introduction of 1 h at the temperature range of 200–280 ℃. The poison processing and mechanism were systematically investigated. It was found that the Nap preferentially consumes active oxygens on the catalyst to form phthalic anhydride (PA) with a higher boiling point, which covers the active sites and leads to the deactivation of VWTi catalyst. Temperature affects the accumulation of deposits and the conversion rate of Nap, thus poisoning effect of Nap on VWTi is temperature-sensitive. The deposited Nap can be removed at high temperatures. Therefore, the inactivated catalysts can be regenerated by high temperature treatment.

Применение кальций содержащих техногенных материалов глиноземного производства в качестве мелиорантов

For utilization of sintering furnace gas purification facilities dust, in addition to the closed dust-turnover scheme, it is proposed to partially withdraw it from the electrostatic precipitators and direct it for use in agriculture. The fields of electrostatic precipitators of alumina production furnaces contain various chemical compounds, therefore it is advisable to use the dust, selected from 1-3 fields of electrostatic precipitators of sintering furnaces, containing more than 30% calcium oxide, as fine powder as ameliorant for deoxidation of soils. The positive influence of introducing wastes of gas-cleaning facilities of sintering furnaces into acidic soil on the increase of morphometric indicators of plant development, germination energy, germination rate, mass of sprouts of test cultures (garden cress and soft spring wheat) has been shown. Experimental studies have shown that plants that were grown in the soil with the addition of this dust have a more developed root system and stronger shoots. Keywords: ECOLOGY, SPECKING STOVES, ELECTROPHILTER DUST, AGRICULTURE, MELIORANT, ACIDIC SOILS

Contribution of Na/K Doping to the Activity and Mechanism of Low-Temperature COS Hydrolysis over TiO2-Al2O3 Based Catalyst in Blast Furnace Gas

As an organic sulfur pollutant generated in blast furnace gas, carbonyl sulfide (COS) has attracted more attention due to its negative effects on the environment and economy. The TiO2-Al2O3 composite metal oxide (Ti0.5Al) with uniformly dispersed particles was prepared by the co-precipitation method. And on this basis, a series of Na/K-doped catalysts were prepared separately. The activity evaluation results showed that the introduction of Na/K significantly improved the low-temperature COS hydrolysis activity, which exhibited a COS conversion of 98% and H2S yield of 95% at 75 °C with 24,000 h–1. And K showed a better promoting effect than Na. Brunauer–Emmett–Teller (BET) results revealed the increased mesopore proportion of Na/K-modified catalysts. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that Na and K formed prismatic and nanorod-like structures, respectively. More weakly basic sites with enhanced intensity and decreased Oads/Olat content contributed to the excellent catalytic activity, as certified by the results of CO2 temperature-programmed desorption (CO2-TPD) and X-ray photoelectron spectroscopy (XPS). It was also proposed that the decrease of weakly basic sites ultimately deactivated catalyst activity. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed that the introduction of Na/K enhanced the dissociation of H2O, and the generated abundant hydroxyl groups promoted the adsorption of COS and formed surface transition species, such as HSCO2– and HCO3–.