H2S Removal Efficiency Research Articles

Sulfur recycle in biogas production: Novel Higee desulfurization process using natural amino acid salts

In this work, a desulfurization method using natural amino acid salts (AAS), which can be green prepared by biological fermentation, is proposed to remove H2S from raw biogas. Biogas purification and fertilizer production can be simultaneously achieved to close sulfur recycle. The reaction kinetic characteristics of H2S absorption with three kinds of AAS, including potassium β-alaninate (PA), potassium sarcosinate (PS) and potassium l-prolinate (PP) are first studied. Kinetic parameters including orders of reaction, rate constants, pre-exponential factors and activation energies are given. AAS absorbent exhibits good potential for biogas desulfurization. Higee (high gravity) technology is utilized to intensify H2S removal. The effects of operating conditions on H2S removal efficiency are investigated and PP shows the best desulfurization performance. The phytotoxicity of AAS and amino acid salt sulfide (AASS) is assessed by the germination index of mungbean seeds. PP and its salt sulfide (PPS) show relatively low phytotoxicity and their allowable agricultural feeding concentrations are below 0.08 M and 0.04 M, respectively. The desulfurization method demonstrates a green route for biogas purification to achieve sulfur recycle.

Production and purification of biogas from cassava peel using cow dung as inoculum

The study examined biogas production from cassava peel and cow dung due to the large quantity of cassava peel disposed at dumpsites in local cassava processing sites. A 200L biodigester was used for the experiment. It contained 25 kg of cassava peel, 25 kg of cow dung and 100 kg of water in the ratio of 1:1:4, respectively. A cumulative volume of 937.3L of biogas was generated after the 30 days digestion period. The biogas generated was pass through a combined absorption and adsorption pre-treatment process to reduce the concentration of impurities in the biogas. The procedure had a 91.5% CO2removal efficiency and 88% H2S removal efficiency. The biogas, after purification can be used for cooking. Also, the digestate from the anaerobic digestion process is rich in NPK, which can be used as fertilizer.

Efficiency, Economic, Energy, and Safety (3ES) Analyses on Different Configurations of MDEA Absorption Process for Coke Oven Gas Desulfurization

The purification of Coke Oven Gas received great attention due to its high potential of utilization for power generation and hydrogen production. This study simulated different configuration of MDEA process flowsheet and implemented the comprehensive evaluation. The comprehensive evaluation included H2S removal efficiency, energy consumption, techno-economic analysis, and safety assessment. The modified MDEA processes applied additional flash drums to enhance H2S removal efficiency and reduce heat duty of distillation column reboiler. MDEA with two intermediate flash drums showed the highest efficiency (96.5%), lowest reboiler duty (6.27 MW), and the lowest operation cost ($ 50/ Nm3-y). Conventional MDEA process exhibited the lowest capital cost ($ 1.531 million) and H2S leakage amount (30.3 kg) for an accident. MDEA with two flash drums process can be recommended when high purity coke oven gas was required. Conventional MDEA was recommended to consider safety and short-term operation with the lowest capital cost. MDEA with one flash drum can be recommended for stable desulfurization operation.

Integrated on-site collection and off-site analysis of airborne molecular contamination in cleanrooms for integrated circuit manufacturing processes

Both long-term on-site collection and off-site analysis methods were conducted to investigate airborne molecular contaminants (AMCs) in a semiconductor wafer cleanroom. The removal efficiency of SO2 and NO2 for chemical filters on a make-up air unit (MAU) in the cleanroom is approximately 50%, though this value does not meet the removal efficiency mentioned in the GB 36306 standard. The removal efficiencies of SO2, H2S, NO, NO2, NH3, and TVOC were approximately 76.5%, 50.9%, 83.5%, 99.3%, 94.8%, and 97.1% after the fan filter unit (FFU) was equipped with a chemical filter. AMCs mainly include benzene, toluene, ethylbenzene, xylene (BTEX), alkanes and alkenes, though BTEX accounts for 77% of the total. VOC concentrations in cleanrooms fitted with FFU chemical filters and where the process equipment was not in operation were found to be lower than those at domestic residences and slightly higher than those found in commercial aircraft cabin air. The daily average TVOC concentrations were negatively correlated with temperature (R2 = 0.46, p < 0.01) and positively correlated with humidity (R2 = 0.26, p < 0.01). The daily average NH3 concentrations were negatively correlated with T (R2 = 0.19, p < 0.05) and positively correlated with RH (R2 = 0.18, p < 0.01). Dibutyl phthalate (DBP) and dioctyl phthalate/diethylhexyl phthalate (DOP/DEHP) were detected in the new sealing joint strips in the HEPA filters. Phthalates and organophosphates were not detected in the new filter papers.

Application of palm oil mill waste to enhance biogas upgrading and hornwort cultivation

The potential of oil palm ash (OPA) to enhance H2S and CO2 removal from biogas by scrubbing with maturation pond effluent (MPE), and further the treatment of biogas scrubber effluent (BSE) by Ceratophyllum demersum L. (hornwort) cultivation were investigated in this study. The results show that OPA + MPE solution with pH 9.3 and alkalinity 7525 mg CaCO3/L was obtained with 0.7 kg/L OPA loading. A pilot scale scrubber was used to study the effects of absorbent flow rates of 60–210 L/h on upgrading to 300 L/h field biogas stream. At 210 L/h, the CO2 removal efficiencies were 33% and 53% for MPE and OPA + MPE, respectively. To approach 100% H2S removal efficiency, the minimum flow rates were 120 L/h for MPE and 90 L/h for OPA + MPE. 50–150 g wet weight of hornwort in 30 L diluted POME were loaded to investigate appropriate initial hornwort loading level for hornwort cultivation. The highest specific growth rate of 0.045 day−1 with biomass production of 3.8 g/day were obtained with a 50 g initial loading. Among the wastewaters (MPE, OPA + MPE, and BSE) treatment using hornwort cultivation, the highest 0.035 day−1 specific growth rate and 2.6 g/day biomass production of hornwort were obtained in diluted BSE cultivation, and in 3 weeks of cultivation. COD, nitrate, phosphate, and alkalinity decreased by 76%, 76%, 55%, and 5%, respectively. The Eco-Efficiency concept for palm oil mill waste utilization proposed in this study has a high potential for enhanced biogas upgrading by using OPA + MPE, and hornwort is a good candidate for BSE post-treatment integrated with biomass production.

Desulfurization performance in a HiGee reactor with packing containing different fiber cross-sectional shapes

HiGee reactors have been utilized for H2S removal from offshore natural gas by chelated iron solution, which exhibits great advantages due to their compact footprint. However, the blockage of packing in HiGee reactor caused by sulfur generation can lead to a decline of desulfurization efficiency. Herein, the fiber cross-sectional shape of mesh packing was optimized for alleviating blockage based on the understanding of liquid flow behavior with various single-layer meshes in our previous studies (Wen et al., Chem. Eng. Sci. 2022, 248, 117147). The novel packing with vertical quadrangular fibers and horizontal elliptical fibers (VQHE) as well as the conventional packing with circular fibers (VCHC) were designed and fabricated by three-dimensional printing technology. A rotating packed bed (RPB) reactor with mesh packing, as one of the typical HiGee reactors, was adopted for H2S removal. Results indicate that H2S removal efficiency of VQHE could reach up to 99.3%. The mass transfer coefficient of VQHE was 25.9% higher than that of VCHC. Meanwhile, the photograph displays that less sulfur solid was deposited on the surface of VQHE. The mass increase ratio of VQHE was smaller by 24.9% than that of VCHC. VQHE realized the integration of enhancing H2S removal efficiency and alleviating blockage in RPB reactor.

A thermally activated double oxidants advanced oxidation system for gaseous H2S removal: Mechanism and kinetics

A thermally activated double oxidants (Oxone/H2O2) advanced oxidation system is used for gaseous H2S removal. Several fundamental issues for H2S removal, e.g., process parameters, products, synergy activation mechanism of free radicals, desulfurization mechanism and kinetics were systematically explored. Compared with single oxidant activation systems, double oxidants activation system shows higher free radical yields and H2S removal efficiencies. Temperature demonstrates a critical role in producing free radicals and removing H2S. With the raise of Oxone concentration (0 to 0.6 moL/L), the H2S removal efficiency is first increased greatly, and then is slightly increased. A double change is discovered for removing H2S when H2O2 concentration or activating temperature is increased continuously (optimization values are 0.8 moL/L and 338 K, respectively). Removal efficiency of H2S is increased through raising pH value and liquid-gas ratio, while is declined via raising H2S content. Sulfate and elemental sulfur are determined to be the main final products, and no by-products are formed. Oxidation by OH and SO4− is confirmed to be the primary pathways for removing H2S. Kinetic study discovers that the H2S removal process belongs to a pseudo-first-order reaction and complies with two kinds of kinetic characteristics (i.e., fast reaction and medium reaction) depending on different experimental operating conditions.

Adsorption of Hydrogen Sulfide (H2S) from Municipal Solid Waste by Using Biochars

The emission of hydrogen sulfide (H2S) from municipal solid waste is one of the environmental issues that raised the public’s attention and awareness. Exposure to H2S that brings a foul smell of rotten eggs will cause headaches, irritation, dizziness, fatigue, and even death if the concentration of H2S is too high. The study’s goals are to investigate the properties of biochars made from rice hulls, banana peels, and sawdust; to compare the biochars’ physical and chemical properties; and establish the H2S removal efficiency of the three biochars. Biochars derived from rice hull (RHB-500), banana peel (BPB-550), and sawdust (SDB-500) by pyrolysis were used as the adsorbents. The biochar yield, pH, ash content, surface functional group, and morphology of the biochars produced were investigated. In this study, H2S was synthesized by mixing food waste and soil in the experimental column. The H2S produced was reduced by the adsorption method. The removal efficiencies of H2S for each biochar were determined by allowing the synthetic H2S to flow through the two columns that were packed with sand (act as control) and biochars, respectively. All biochars were alkaline, and BPB-550 had the highest pH, followed by SDB-500 and finally RHB-500. The order for removal efficiency of H2S (&gt;94%) is BPB-550 &gt; SDB-500 &gt; RHB-500. Overall, the biochars derived from biomass had a strong ability to act as the adsorbents for H2S removal.

The comprehensive evaluation of available pilot-scale H2S abatement process in a coke-oven gas: Efficiency, economic, energy, and environmental safety (4ES)

This study implemented the comprehensive evaluation of desulfurization efficiency-energy potential-economic-safety into three different processes for removing hydrogen sulfide from coke oven gas. Three different processes were NH3 absorption, MDEA process, Fumaks wet oxidation process. NH3 and MDEA process utilized the conventional absorption-stripping configuration with absorbent while the wet oxidation process was composed of two consecutive H2S removal processes. Energy potential and safety assessment were augmented besides conventional assessment such as economic and removal efficiency. The energy potential of coke oven gas was evaluated in terms of Low heating value. The dispersion distance of H2S gas was evaluated in case of leakage accident for safety assessment. The desulfurization efficiencies of NH3 absorption, MDEA, wet oxidation were 76.5%, 94.3%, 99.0%. For evaluating energy potential low heating value of NH3 absorption, MDEA, wet oxidation were 17.81 MJ/m3, 17.89 MJ/m3, and 18.37 MJ/m3. The capital costs of NH3 absorption, MDEA, wet oxidation were $ 38.0/Nm3∙y, $ 50.6/Nm3∙y, and $ 67.5/Nm3∙y. Overall, the wet oxidation exhibited the highest H2S removal efficiency and energy potential but the highest cost required and relatively high H2S dispersion distance. The MDEA showed moderate performance on efficiency, cost, and safety. The NH3 absorption process showed the cheapest cost consumed and relatively safe but lowest H2S removal and energy potential. Wet oxidation, Therefore, wet oxidation would be suited for meeting strict environmental regulations. MDEA process would be suited for power utilization and less strict environmental regulation with lower cost. NH3 absorption would be suited for direct utilization to other processes.

Upgrading biogas to biomethane using untreated groundwater-NaOH absorbent: Pilot-scale experiment and scale-up estimation for a palm oil mill

A caustic absorbent like NaOH used in biogas upgrading can be recycled by regeneration at a moderate temperature. Using untreated groundwater to prepare the absorbent is cost saving, but the of CO2 and H2S removal efficiencies from biogas need to be confirmed. 60 experiments were performed in pilot scale scrubber for data on operating conditions vs removal efficiency. It was found that the removal efficiencies were not significantly different between using groundwater and softened water to prepare the NaOH, even though 0.3–0.4% of precipitate was found in NaOH solution when using groundwater. 99% removal efficiencies of CO2 and H2S were achieved at the minimum NaOH concentration of 4 g/L and L/G ratio of 0.3. The operating conditions for specific biomethane concentration requirements are tabulated, and the relation of operating conditions to CO2 removal efficiency is provided as an empirical correlation. Moreover, there was a good agreement between the experimental data and the simulation by Aspen HYSYS using the Acid Gas-Caustic Wash method. The caustic scrubber was then simulated for the 500 m3/h biogas production rate, and the chosen column diameter and height were 1 m and 6 m, respectively, which is 30 fold smaller in volume compared to the bio scrubber for which no CO2 removal was observed. For bio methane production, this study reveals the potential to use a cost saving caustic scrubber to replace the bio scrubber.

Mill Scale Addition to Reduce Hydrogen Sulfide Production in Anaerobic Digestion

Direct addition of sulfur-reducing agents during anaerobic digestion (AD) is very effective in controlling hydrogen sulfide (H2S) content in biogas, although one major problem is the high operational cost due to the large amount of chemicals used. The objective of this study was to remove H2S using a waste mill scale (MS) as a sulfur-reducing agent. To evaluate its feasibility, MS was added to AD fed with food waste (FW) at concentrations between 0 and 160 g MS/kg total chemical oxygen demand (TCOD) during the batch test, and the experimental results were compared to those of the batch test with the addition of iron chloride (FeCl3). Both FeCl3 and MS played an important role as electro-conductive materials in improving methane productivity by promoting direct interspecies electron transfer. An increase in H2S removal efficiency was observed with increases in both materials. In total, 30%, 60%, and 90% of H2S production based on the maximum sulfur in the form of H2S (control) was 3.7, 9.4, and 23.8 g FeCl3/kg TCOD and 13.3, 34.1, and 86.2 g MS/kg TCOD, respectively. This finding indicates that MS can be used as a sulfur-reducing agent substitute for H2S removal in AD fed with FW.

Retrofitting and simultaneous multi-criteria optimization with enhanced performance of an industrial gas-cleaning plant using economic, process safety, and environmental objectives

Natural gas is one of the main sources of energy. Due to the abrupt change of oil and gas price in the global market, it is important to improve the production process and make it profitable in a sustainable manner. The purpose of the current study was to further enhance the performance of the methyl diethanolamine (MDEA) process plant by retrofitting the NG sweetening plant and subsequent multi-criteria optimization studies. Most of the literature studies focused on modeling and sensitivity analysis with little attention to the retrofitting aspects of the gas sweetening unit. Therefore, process retrofitting and simultaneous multi-objective optimization of the natural gas cleaning process using an elitist nondominated sorting genetic algorithm was carried out for the methyl diethanolamine solvent to improve the performance of the absorption well as regeneration column. Seven operating parameters and four conflicting objective functions were considered to formulate two-objective, three-objective, and four-objective optimization problems. Two separate models, i.e., (1) base case and (2) improved retrofitting case, were developed in ProMax process simulator software, and these were validated with actual plant data. All the optimization problems were solved with the base model and improved retrofitting model, and the Pareto optimal fronts were obtained. Up to 17.5% reduction on process safety indicator damage index (DI) was obtained for the lean-vapor compression (LVC) plant configuration considering the same actual plant return on investment (ROI) of 97.44% without affecting H2S removal efficiency. The retrofitted process with LVC can achieve a 42% reduction of acidification potential (AP) and 29% reduction of global warming potential (GWP) compare to the normal process. Therefore, the LVC process can give enhanced plant performance with H2S removal of 99.38%, which leads to the improved cleaner production of natural gas. However, the retrofitted process provides a comparative economic benefit than the existing process.

Cu-Zn oxides nanoparticles supported on SBA-15 zeolite as a novel adsorbent for simultaneous removal of H2S and Hg0 in natural gas

Inspired by the fact that H2S can easily decompose on some metal oxides to form sulfur species and the resulting products are usually used as Hg0 removal active sites, a novel Cu-Zn mixed oxide supported SBA-15 zeolite was controllably synthesized for simultaneous removal of Hg0 and H2S. The Cu-Zn nanoparticles with a particle size range of 4.4–5.0 nm were successfully confined and uniformly dispersed in the two-dimensional mesopores of SBA-15. The obtained 1Cu1Zn/SBA-15 adsorbent presented an outstanding H2S and Hg0 removal efficiencies at 30 °C and 30,000 h−1, and the H2S and Hg0 capture capacities reached to 296.78 mg·g−1 and 12.75 mg·g−1 at a 10% breakthrough. In addition, the spent adsorbent could be regenerated in a 5% O2 and 95% N2 atmosphere at 600 °C without obvious degradation of adsorption capacities over five cycles. We considered that the doping effects of Cu-Zn oxides were beneficial for its excellent H2S and Hg0 removal performance at low temperatures, and the nano-confinement effect of SBA-15 was conducive to prevent the oxides nanoparticles from agglomeration in the regeneration process, thus achieving the outstanding regeneration performance. Furthermore, the polysulfide polymer formed by chemisorption of H2S on the Cu-Zn oxides surface was confirmed to be the Hg0 active sites, which could react with gaseous mercury to form HgS. This work provided an effective way for simultaneous removal of H2S and Hg0 in natural gas by confining nano-sized active metal oxides into the mesopores of zeolites.

Selective Catalytic Oxidation of Lean-H2S Gas Stream to Elemental Sulfur at Lower Temperature

Ceria-supported vanadium catalysts were studied for H2S removal via partial and selective oxidation reactions at low temperature. The catalysts were characterized by N2 adsorption at 77 K, Raman spectroscopy, X-ray diffraction techniques, and X-ray fluorescence analysis. X-ray diffraction and Raman analysis showed a good dispersion of the V-species on the support. A preliminary screening of these samples was performed at fixed temperature (T = 327 °C) and H2S inlet concentration (10 vol%) in order to study the catalytic performance in terms of H2S conversion and SO2 selectivity. For the catalyst that exhibited the higher removal efficiency of H2S (92%) together with a lower SO2 selectivity (4%), the influence of temperature (307–370 °C), contact time (0.6–1 s), and H2S inlet concentration (6–15 vol%) was investigated.

Impact of an anoxic desulfurization process on methane content of the purified biogas

This study showed the impact of an anoxic desulfurization process on the CH4 and CO2 content of the purified biogas. The desulfurization system was implemented in an anoxic bioscrubber, which supported H2S removal efficiencies ranging from 92 ± 8 to 97 ± 6% for H2S loading rates between 28.3 and 37.8 g S mliquid-3h−1. CO2 absorption during the desulfurization process mediated a slight reduction in the CO2 concentration from 39.5% in the raw biogas to 36.5–38.2% in the purified biogas. Such reduction in the CO2 concentration was proportional to the increase of CH4 concentration recorded, passing from 60.0% in the raw biogas to 61.7–63.5% in the purified biogas. Bacterial community characterization by means of 16S rRNA high-throughput sequencing revealed the consistent presence of both methanotrophs (Methylibium, Methylomonas and Methylosinus genera) and methanol-oxidizing denitrifiers (Simplicispira and Methyloversatilis genera), which suggested that methane oxidation indeed occurred. The quantification of a potential CH4 uptake in the desulfurization process was hindered by the CO2 absorption observed, however, strategies for quantifying biological CH4 consumption in anoxic desulfurization systems are proposed and discussed, based on the results herein obtained.

Natural gas sweetening using TEGMC polyimide hollow fiber membranes

Raw natural gas contains a significant range of impurities, i.e. H2S, CO2, C2, C3, C6+ etc. The acidic H2S and CO2 are especially highly corrosive to processing and transporting equipment and cause serious environmental issues. In the current study, we investigated H2S and CO2 removal efficiency of TEGMC (TriEthylene Glycol Monoesterified Crosslinked) hollow fiber membranes under realistic natural gas sweetening conditions. The membranes had been stored under ambient condition over seven years but still show good gas separation performance without any particular regeneration treatments. Unexpectedly, the presence of various hydrocarbons, i.e. C2, C3, and toluene, in the feed gas enhances both H2S/CH4 and CO2/CH4 selectivity. Indeed, the condensable hydrocarbons suppress the CH4 permeation through competitive sorption with less effect on the permeation of H2S and CO2. Such a phenomenon is unique in membrane separations, suggesting that penetrant competition can be a useful tool rather than a problem to tune the membrane performance in some cases.

Impact of nickel nanoparticles on biogas production from cattle manure

The presence of nano-nutrients can be stimulatory for the anaerobic digestion (AD) of hardly degradable wastes and thus enhance process performance. One of the essential trace elements, nickel (Ni), is involved in multiple important enzymes necessary for efficient AD. This study investigated the effects of Ni nanoparticles (NPs) with different concentrations on cattle manure AD performance and effluent chemical composition. The results showed that the highest specific biogas production was attained with 4 mg/L Ni NPs (p<0.05) and was 792.00 mL/g VS compared with cattle manure-only which yielded only 589.20 mL/g VS. Moreover, the addition of 2 mg/L Ni NPs significantly increases the methane yield (p<0.05) by 70.46% compared with cattle manure-only. Besides, H2S production decreased by 16.50%, 90.47%, and 51.89% compared with cattle manure-only when the cattle manure was treated by 1, 2, and 4 mg/L Ni NPs, respectively. The supplementation of bio-digester with 2 mg/L Ni NPs improved the total and volatile solids removal efficiencies by 19.2% and 12.1% and maintained pH at a suitable level (6.8–7.3). FTIR spectrum of effluent presented the addition of Ni NPs changed the intensity and shift of peaks compared with cattle manure-only peak. Moreover, all of the effluent samples from the AD systems using Ni NPs showed stronger fertilizer values, as well as the effluent with 2 mg/L Ni NPs, had the highest sulfide content (31.2%, increase), leading to higher H2S removal efficiency by 47.5%. A first-order kinetic model showed an increase up to 1.88-fold in the hydrolysis rate constant (K), in 4mg/L Ni NPs compared to cattle manure-only, leading to higher biogas yield.

Study on the desulfurization performance of iron/ethanolamine/deep eutectic solvent system.

Deep eutectic solvent (DES) was applied as the solvent of iron/alcohol amine system, and the prepared iron/ethanolamine/DES system was found to be a good desulfurizer for H2S removal. The absorbents were characterized by Fourier transform infrared spectroscopy. The iron/ethanolamine/DES system showed a significantly enhanced desulfurization performance compared with DES solution of iron or alcohol amine separately. Besides, the absorbents showed relatively stable desulfurization performance, which could keep a high H2S removal efficiency in a wide temperature range from 30-90°C. The iron/ethanolamine/DES system could be recycled for at least three times. The desulfurization product was analyzed by energy dispersive spectrum and X-ray diffraction, and the desulfurization product was identified as sulfur element.

Effect of H2S and NH3 in biomass gasification producer gas on CO2 capture performance of an innovative CaO and Fe2O3 based sorbent

This study has investigated the effect of contaminants in biomass gasification producer gas on the CO2 capture performance of an innovative CaO and Fe2O3 based sorbent material. It is well known that biomass gasification producer gas contains gaseous contaminants such as H2S and NH3. Experiments were conducted with the combined contaminants of H2S at 230 ppmv and NH3 at 2300 ppmv. Each run of the experiment included three major stages: H2 reduction, CO2 capture (carbonation) and CO2 release (calcination). The operation temperature was controlled at 650 °C with a duration of 3 h at the carbonation stage, and at 850 °C with a duration of 2 h at the calcination stage. In each experiment, three cycles of carbonation-calcination were performed.The experimental results show an average CO2 capture efficiency of 61.8% during the carbonation stage in the first cycle, reducing to 45.4% in the third cycle. However, effective CO2 capture was achieved in the initial 20 min of carbonation, with a capture efficiency of 75.1% for the first cycle and 62.8% in the third cycle.It was found that the CO2 sorbent can effectively remove contaminants from the producer gas, showing catalytic effect of the sorbent material. The H2S removal efficiency decreased from 99% in the first cycle to 82% after three cycles, while the NH3 removal efficiency was above 99% for all three cycles during the carbonation stage. Furthermore, concentrations of the N-based and S-based compounds in the outlet gas streams during calcination were examined for the potential impact when the gas is injected into plant nursery greenhouses for growth enhancement. Fundamental analysis was also performed and microstructural changes in the material were examined to understand the CO2 capture process by the tested sorbent.

Simultaneous removal efficiency of H2S and CO2 by high-gravity rotating packed bed: Experiments and simulation

Abstract This study explores the possibility of applying high-gravity rotating packed bed (HGRPB) in removing H2S and CO2 from biogas. Ca(OH)2 aqueous solution was used as the absorbent in this study. Different experimental conditions including solution pH, rotating speed (R S) of HGRPB, gas flow rate (Q G), and liquid flow rate (Q L) were investigated with respect to the removal efficiency (E) of H2S and CO2. The experimental and simulated results show that the optimal removal efficiency of H2S and CO2 using HGRPB achieved nearly the same as 99.38 and 99.56% for removal efficiency of H2S and 77.28 and 77.86% for removal efficiency of CO2, respectively. Such efficiencies corresponded with the following optimal conditions: a solution pH of 12.26, HGRPB reactor with the rotating speed of 1,200 rpm, the gas flow rate of 2.46 (L/min), and the liquid flow rate of 0.134 (L/min).