H2S Removal Research Articles

Continuous H2s Removal from Biogas Using Purple Phototrophic Bacteria

Continuous H2s Removal from Biogas Using Purple Phototrophic Bacteria

Anti-corrosion MgO nanoparticle-equipped graphene oxide nanosheet for efficient room-temperature H2S removal

Enhanced room-temperature H2S removal on homogenized metal oxide nanoparticle-loaded 2D carbon nanosheets is reported. Band gap of metal oxides and degree of their bands mixing with H2S orbitals are crucial for anti-corrosion oxidation of H2S.

Preparation of magnesium oxide confined in activated carbon synthesized from palm kernel shell and its application for hydrogen sulfide removal

In this study, magnesium oxide (MgO) confined in porous carbon was synthesized and the efficacy of this material was analyzed for hydrogen sulfide removal. The palm kernel shell was carbonated to obtain the porous carbon material (labelled as AC-TKS). The confinement of magnesium oxide was carried out by the incipient wetness impregnation process of a metal oxide precursor followed by calcination. The MgO content in porous carbon was optimized to maintain a 5 wt. % total content of oxide (MgO-5%/AC-TKS). Materials were characterized using N2-sorption analysis, X-ray diffraction (XRD) and scanning electron microscopy-EDX (SEM-EDX). AC-TKS has a high specific surface area (SSA) of 708 m2/g. Meanwhile, the specific surface area decreased by up to 50% (ca. 248 m2/g) for MgO-5%/AC-TKS caused by the blocking of the MgO content. The successful confinement process was proven by X-ray diffraction analysis which revealed that MgO was formed by the appearance of MgO peaks. This is supported by the results of SEM-EDX mapping, which showed the presence of Mg and O elements on the carbon surface. The higher H2S removal was shown by MgO-5%/AC-TKS which could reduce H2S up to 98.6% and showed a better performance compared to only porous carbon.

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.

Low-temperature preparation of cupric spinel for room-temperature removal of hydrogen sulfide to value-added product ammonia formation

Spinel-type compounds are extremely effective in the adsorptive removal of gas pollutants. However, they are prepared at high temperatures, and their lack of catalytic production of value-added products deserves further research. This study focused on the preparation of cupric spinel compounds at low temperatures and their application to H2S removal with value-added product formation. Cupric spinel (CuFe2O4) was prepared by the co-precipitation of bivalent copper and trivalent iron at 60 °C, which allowed the formation of CuFe2O4 with a high surface area of 202.72 m2/g. The obtained breakthrough capacity was 5.68 mg H2S/g in ambient temperature removal of H2S. The analysis of outflowing gas by online sensor demonstrated the formation of 73.75 mg NH3/g spinel compound. The sulfide compound presented in the sample analysis supported the NH3 formation at the end of H2S removal, that is, NH3 was synthesized at ambient temperature after the formation of sulfide compound. Successfully prepared the CuFe2O4 at a low temperature and its application on H2S removal with value added product NH3 formation achieved at ambient temperature.

Removal of gaseous H2S using microalgae porous carbons synthesized by thermal/microwave KOH activation

H2S has strong toxicity and corrosivity, which can endanger human health and corrode equipment. This article used the two types of activation methods as a comparison to activate raw biochar from microalgae pyrolysis to prepare microalgae porous carbon for removal of gaseous H2S. The difference in textural properties and functional group of the prepared microalgae porous carbon using two types of activation methods is studied emphatically. Then physicochemical property of microalgae porous carbons was characterized and effect of activation methods, KOH/raw biochar mass ratio and sorption temperature on desulfurization was tested. Sorption products, mechanism, kinetics and thermodynamics were studied. Reuse of deactivated adsorbents was also explored. Research revealed that both activation methods substantively improved pore structure and increased active functional group contents of raw biochar, greatly promoting desulfurization. Compared to thermal activation, active functional groups of microalgae porous carbons prepared by microwave-assisted activation had no obvious difference, but pore structure was greatly improved, leading to higher H2S sorption capacity. Results of product characterization, thermodynamics and kinetics demonstrated that in the H2S sorption process, physical sorption was major and chemical sorption was auxiliary. Spent containing-sulfur microalgae porous carbons showed good Hg0 capture ability, far exceeding commercial activated carbon.

Biological removal of gas‐phase H2S in hollow fibre membrane bioreactors

AbstractBACKGROUNDHydrogen sulphide (H2S) must be treated at its emission source to avoid health risks, odour, and corrosion. Conventional physico‐chemical H2S removal technologies (for example, membrane contactors or chemical scrubbers) have several limitations, such as requiring high amounts of absorption chemicals and energy. In contrast, biological H2S removal technologies are environment friendly, easy to operate, and less expensive due to their low energy requirements. In this study, the feasibility of a porous hydrophilic polyethersulfone hollow fibre membrane bioreactor (HFMB) was tested for the biological removal of gas‐phase H2S by employing three lab‐scale reactors (two biotic and one abiotic). The HFMBs were operated at ~20 °C for ~3 months, employing different H2S inlet loading rates (ILR) and an empty bed residence time of 187 s.RESULTSBiotic performance of the HFMBs demonstrated that the removal efficiency (RE) varied between the different inocula and was in the range of 80–100% for the applied H2S ILR of ~5.0–7.5 g m−3 h−1. The RE reached a constant value of ~100% in both biotic reactors at an ILR of ~17.0 g m−3 h−1 when using acclimatized inoculum. The biotic HFMBs demonstrated ~5–9 times higher H2S flux and ~ 20–26 times higher mass transfer compared to the abiotic control. Surface morphology revealed attached microbial growth on the outer surface of the membranes, while the high throughput sequencing confirmed the richness of H2S oxidizing microbial communities on the shell side.CONCLUSIONThe obtained results confirm that the HFMB configuration is suitable for biological treatment of H2S laden waste gas. © 2021 Society of Chemical Industry (SCI).

Efficient removal of carbonyl sulfur and hydrogen sulfide from blast furnace gas by one-step catalytic process with modified activated carbon

The performance of modified activated carbon (AC) and the reaction mechanism for the one-step removal of COS and H2S from blast furnace gas were investigated by improving the catalyst preparation conditions. Optimal performance was achieved when the reaction temperature was 60 °C, the oxygen concentration was 0.1 vol%, and the catalyst was prepared by drying at 110 °C. A combined sulfur capacity of 218.21 mg/g was achieved, and the desulfurization mechanism was revealed through a series of characterization methods. The COS in the inlet gas was captured on the catalyst surface under the action of alkaline sites and was subsequently hydrolyzed to H2S. The generated H2S and the original H2S dissociated within the water film on the catalyst to generate HS- and H+. The lattice oxygen of CuO and Cu2O was activated, and the active oxygen oxidized most of the HS- to elemental S. Meanwhile, some of the HS- combined with metal ions to form sulfides, and CoPcS acted as an auxiliary to facilitate this oxidation process. The elemental S was further oxidized by reacting with H2O to form sulfuric acid, which interacted with the active components to form sulfate. This process eventually led to the deactivation of the catalyst.

Regenerable Sorbent Pellets for the Removal of Dilute H2S from Claus Process Tail Gas

The Claus process is the most important sour gas sweetening process to recover elemental sulfur from H2S, which is present in raw natural gas and byproduct gases from crude oil refineries. However, current methods for treating the tail gas of the Claus process are expensive and often not environmentally friendly. Various sorbents have been reported for H2S capture, but few reports focus on the pellet design, formation, and testing. In this study, we developed a pelletization method to prepare sorbent pellets with high sulfur capacity and good regenerability for the removal of dilute H2S from Claus process tail gas. The sorbent pellets consisted of mixed metal oxides of Cu, Mg, and Al with fumed silica as the binder and were characterized using various techniques, including X-ray and electron diffraction, N2 sorption, and scanning and transmission electron microscopy. The H2S sorption capacity was evaluated by breakthrough experiments at 150 °C in a gas stream consisting of 100 ppm of H2S in N2. The optimized sorbent pellets gave a stable breakthrough sulfur capacity of ∼5 mmol/g over three cycles of sulfidation and regeneration. They exhibited an average radial crush strength of 154 ± 40 N.

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 (>94%) is BPB-550 > SDB-500 > RHB-500. Overall, the biochars derived from biomass had a strong ability to act as the adsorbents for H2S removal.

Insight into the influence of Ni2+ doping on the room temperature desulfurization/regeneration performance of ZnO supported MCM-41 adsorbents

Ni2+ doped ZnO/MCM-41 adsorbents with various doping content were prepared by melt infiltration method and its effect on the room temperature desulfurization and regeneration performance of ZnO adsorbents were systemically investigated. The experimental results indicated that the H2S removal capacity of the adsorbents first increased and then decreased with increasing the Ni2+ doping content, its value reaches the highest of 72.5 mg/g when the Ni2+ doping content is 3 at.%. The improved desulfurization performance was attributed to the decreased grain sizes of ZnO nanoparticles and the increased numbers of Lewis acid sites on its surface, the former affords more active sites towards H2S removal and the latter promoted the dissociation of H2S through acid-base reaction. It also found that Ni2+ doping has a negative effect on the regeneration performance of ZnO adsorbents. The incomplete regeneration of ZnS plus the collapse of adsorbents’ framework structure and the formation of sulfates during the regeneration process are responsible for its inferior regeneration performance.

Sustainability criteria as a game changer in the search for hybrid solvents for CO2 and H2S removal

• Robust multi-criteria screening for CO 2 and H 2 S absorption in water-free solvents. • Polar soft-SAFT validated for a wide range of solvent properties and conditions. • Water-free solvents have a competitive technical edge over aqueous solvents. • Sustainability metrics of water-free solvents calls for greener options. • Holistic solvent evaluation is essential for proper selection. The appearance of hybrid solvents in recent years introduced a potential replacement for aqueous amines for acid gas removal in order to mainly overcome the high energy of regeneration. Yet, the assessment of solvent potentiality remains haphazard with limited information and assessment criteria. In this contribution, we develop and apply a multi-criteria assessment approach built on the use of a molecular-based equation of state, namely, polar soft-SAFT, in combination with sustainability indicators to examine the performance of hybrid solvents for acid gas removal (CO 2 and H 2 S). The first stage of the approach relies on the robust development of the thermodynamic model with available experimental data. Subsequently, with assured fidelity, the model is used in a fully predictive manner to obtain relevant assessment criteria for technical performance evaluation. This is inclusive of standard key performance indicators such as cyclic capacity and energy of regeneration, along with key solvent properties at conditions representative of acid gas removal processes. Additionally, we examine the environmental, health and safety impact of the investigated solvents as a sustainability criteria to select them. This framework has been applied for the first time to six solvents for acid gas removal, including the benchmark solvents aqueous monoethanolamine (MEA) and aqueous diethanolamine (DEA), along with hybrid solvents formulated from chemical solvents such as MEA, or DEA, with physical co-solvents including N-methyl-2-pyrrolidone (NMP), or sulfolane (SFL). The results of the multi-criteria assessment demonstrate that among the six solvents investigated in this work, the overall best performer remains to be the benchmark aqueous MEA. Results also indicate the potentiality of MEA + NMP hybrid solvent in terms of an acceptable compromise between reduced absorption capability and reduced energy of regeneration, compared to aqueous MEA; however, the hybrid solvents fail when applying the sustainability metrics. This work clearly indicates that potential solvents for acid gas removal should be examined following a holistic approach, inclusive of their technical performance and environmental footprint.

Sewage sludge ash-derived materials for H2S removal from a landfill biogas.

H2S removal is a key step for biogas cleaning because this component can lead to premature corrosion of the equipment and its cleaning has a significant cost. The aim of the present work was to assess the use of sewage sludge derived ash (SSA)-materials for H2S removal from a landfill biogas. SSA and mixtures made with SSA, activated carbon (AC) and sand were tested for H2S removal. The best removal efficiency was obtained with the mixture 80%m SSA and 20%m AC, while SSA alone was not a good adsorbent under tested experimental conditions. The materials characterization helped the adsorption mechanism understanding. Indeed, results highlighted that SSA presence stabilizes the pH on a basic range, favorable for H2S dissociation into HS- then its chemisorption. On the other hand, with the microporosity of AC, the contact surface between H2S and oxygen was sufficiently large for chemisorption kinetics. It also appeared that the mixture with sand and AC adorbs non selectively H2S but also other volatile organic pollutants present in biogas. Contrariwise, with SSA/AC mixtures, H2S seems to be selectively chemisorbed.

Screening of zeolites for H2S adsorption in mixed gases: GCMC and DFT simulations

Zeolites with high Si/Al ratio are widely used in industrial desulfurization process because of their stability and hydrophobicity as adsorbents. However, the method to design a practical zeolites and the kinetics of competitive adsorption in multicomponent systems still remain to be studied. The adsorption capacity of H2S in 36 all-silica zeolites with different accessible area and pore size was calculated by the Grand Canonical Monte Carlo (GCMC) method. Identical method was used to simulate the adsorption behavior of H2S in the 5 widely used all-silica zeolites (CHA, BEA, MFI, LTA, FAU). Further, the adsorption properties of H2S in metal-modified SSZ was investigated using the Density Functional Theory (DFT) method. The simulation results display that the zeolites with a pore size of 7–9 Å and a higher accessible area tend to exhibit efficient adsorption at 313 K and atmospheric pressure. For pure H2S component, CHA adsorbs most H2S molecules at atmospheric pressure while FAU are more attractive for removal of H2S at saturation pressure. FAU shows a strong preferential adsorption on H2S in the presence of CO, CO2, H2O and N2. In addition, the Co-SSZ obtained by doping Co on CHA is the most promising adsorbent in this research.

One-step synthesis of ZnFe2O4-loaded biochar derived from leftover rice for high-performance H2S removal

• The RZF was synthesized via one-step carbonation activation of kitchen leftover rice. • ZnCl 2 and FeCl 3 were employed as both activator and precursor for preparing RZF. • The as-obtained RZF delivered outstanding desulfurization capacity and regeneration ability. • The postulated mechanisms of H 2 S removal on the RZF was proposed and verified. Hydrogen sulfide (H 2 S) is a major air pollutant posing a serious threat to the environment and public health. It is highly attractive to develop state-of-the-art adsorbent to remove H 2 S. Herein, a novel ZnFe 2 O 4 -loaded porous biochar (RZF) with a high surface area of 1065 m 2 /g was synthesized via one-step carbonation activation of kitchen leftover rice with ZnCl 2 and FeCl 3 as activators. The optimized RZF-500-1:1 was obtained by rationally adjusting the activation ratio (the mass ratio of leftover rice and ZnFe 2 O 4 ) and pyrolysis temperature. Such RZF-500-1:1 delivered high-performance H 2 S removal with the breakthrough capacity up to 228.29 mg/g at 25 °C, whilst the inactivated biochar (carbonization without activator) only showed a much lower adsorption capacity at circa 12.11 mg/g of H 2 S. The desulfurization conditions had a significant effect on the H 2 S breakthrough capacity, and the adsorbent exhibited better desulfurization performance at room temperature and in the presence of oxygen. The desulfurization mechanism on the ZnFe 2 O 4 -loaded biochar was proposed to be an adsorption-catalytic oxidation coupled process. Moreover, the as-fabricated sample showed high regeneration ability, retaining 91.6% of the initial breakthrough capacity after five regeneration cycles. This novel one-step preparation method would permit a gain of time and energy to obtain efficient activated carbons intended to capture H 2 S.

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.

Zinc oxide nanosphere for hydrogen sulfide scavenging and ferroptosis of colorectal cancer

BackgroundColorectal cancer is a common malignancy occurring in the digestive system and ranks second in cancer mortality worldwide. In colorectal cancer, hydrogen sulfide (H2S) is selectively upregulated, resulting in the further exacerbation of the disease. Therefore, the clearance of H2S and the regulation of the enzymes on the H2S pathways are of great significance for colorectal cancer therapy.MethodsHere, we investigated the H2S content in various clinical tumor tissues from patients and confirmed that overproduced concentration of H2S in colorectal cancer. Accordingly, we developed an H2S-responsive nanoplatform based on zinc oxide coated virus-like silica nanoparticles (VZnO) for the therapy of colorectal cancer.ResultsOwing to its excellent H2S scavenging ability, VZnO could effectively reduce H2S content in colorectal cancer to prohibit the growth of CT26 and HCT116 colorectal cancer cells. Moreover, the removal of H2S in colorectal cancer also leads to tumor inhibition through activating ferroptosis, a non-apoptotic form of cell death. The biosafety-related toxicological and pathological analysis confirmed the low toxicity and high safety of VZnO in colorectal cancer treatment. Furthermore, as an H2S-responsible nanosystem, VZnO appears to have no therapeutic effect on other non H2S rich cancers, such as the 4T1 breast cancer model.ConclusionsWe anticipate that the H2S-depletion-induced ferroptosis strategy using zinc oxide-based nanomaterials would provide insights in designing nanomedicines for colorectal cancer-target theranostics and may offer clinical promise.Graphic abstract

Integrated sol-gel and hydrothermal synthesis of V2O5–TiO2 nanocatalysts for enhanced catalytic removal of H2S

Hydrogen sulfide (H2S) emitted from the petroleum refinery process, landfills, or biogas purification is severely corrosive and has harmful health effects on the human body when inhaled at even small concentrations. Selective catalytic oxidation using V2O5–TiO2 is considered to be a benchmark technology for removing H2S. This paper presents a novel preparation method to synthesize V2O5–TiO2 nanocatalysts to improve desulfurization performance. Compared with the conventional sol-gel or wet-impregnation method, the integrated sol-gel and hydrothermal synthesis allows for a substantial increase in the specific surface area, which is mainly attributed to the highly reduced sizes of the primary particles. The enhanced surface area contributes to effective dispersion of the vanadium (V) species on the TiO2 support, by which the interactions between V and titanium (Ti) are strengthened. Accordingly, the redox properties of the catalysts are improved with increased concentrations of the chemisorbed oxygen species on the catalyst surfaces. Finally, the properties of the V2O5–TiO2 nanocatalysts are improved by the new preparation conditions, resulting in significantly enhanced catalytic activities in the selective oxidation of H2S: the best catalyst exhibits excellent activity even at 50 °C. It was also observed that the temperature during the hydrothermal reaction severely affected the catalytic performance of the V2O5–TiO2 nanocatalysts. This study suggests the importance of the preparation conditions for manipulating the physicochemical properties and performances of catalysts.

H2S catalytic removal at low temperature over Cu- and Mg- activated carbon honeycombs

A series of monometallic and bimetallic Cu/Mg oxide-based structured catalytic sorbents were synthesized by impregnation of extruded activated carbon honeycombs and tested for the purification of simulated biogas from H2S at room temperature. Dynamic H2S (100ppmv) removal tests were run at short contact time under moist conditions in the presence of O2 to compare sulfur capture capacities and to investigate kinetic aspects of the oxidation reactions involved in the mechanism at varying the composition of the active phase. Fresh, exhausted and thermally regenerated honeycomb catalytic sorbents were characterized by N2-adsorption, PSD, XPS, TG-MS to shed light on the specific nature of S-species formed upon catalytic oxidation, the maximum capacity and the efficacy of a simple thermal regeneration treatment at 600 °C. Under moist conditions, the surface chemistry resulted dominated by the basic nature of MgO, and bimetallic CuMg catalytic sorbents show fast H2S removal rates and large S-capacity coupled to easy and complete regenerability.

Comparison of Equilibrium-Stage and Rate-Based Models of a H2S Scrubber for Purification of Coke Oven Gas

In recent years, one of the most important challenges worldwide is to meet increasingly stricter environmental regulations while maintaining the profitability of plants. Modelling particular parts of existing technologies can help efficient operation, reduce energy consumption, minimize emissions, and keep operating costs low. Furthermore, adequately validated models provide the opportunity to examine different equipment designs, operating parameters side by side without hindering the technological process. The coke oven gas purification technology of a Hungarian coke oven plant was studied in this research work. As a by-product of coke production, approximately 40,000 - 60,000 m3 crude coke oven gas is generated every hour, which has to be cleaned before being used for energy purposes. First, the cooled crude coke oven gas is fed into the hydrogen sulfide scrubber in a counter-current flow. Then, the hydrogen sulfide is absorbed in an ammonia-rich washing liquid coming from the following two ammonia scrubbers. In this study, two mathematical models, equilibrium-stage and rate-based models, were used to simulate the removal of H2S from coke oven gas in the Aspen Plus process simulator program. The validation of the models was performed by using the operating measurements of the outlet streams. The results closely approximate the measured composition of the outflows. However, the simulation results predicted by the rate-based model show better agreement than the equilibrium model compared with the experimental data. With the use of the rate-based model, a sensitivity analysis was made, taking into account the parameters that have a tremendous impact on the cleaning process and can also be controlled by appropriate intervention. The creation of this model was the first step in building the simulation of the entire gas purification process, which will be used to optimize the operation and create an operator training system.