Low-pressure Method Research Articles

Preparation of Glass–Ceramics Using Low-Pressure Sintering Method for High-Value Utilization of Blast Furnace Slag

Preparation of Glass–Ceramics Using Low-Pressure Sintering Method for High-Value Utilization of Blast Furnace Slag

Pd Nanoparticle Size-Dependent H* Coverage for Cu-Catalyzed Nitrate Electro-Reduction to Ammonia in Neutral Electrolyte.

Electrochemical conversion of nitrate (NO3 -) to ammonia (NH3) is an effective approach to reduce nitrate pollutants in the environment and also a promising low-temperature, low-pressure method for ammonia synthesis. However, adequate H* intermediates are highly expected for NO3 - hydrogenation, while suppressing competitive hydrogen evolution. Herein, the effect of H* coverage on the NO3RR for ammonia synthesis by Cu electrocatalysts is investigated. The H* coverage can be adjusted by changing Pd nanoparticle sizes. The optimized Pd@Cu with an average Pd size of 2.88nm shows the best activity for NO3RR, achieving a maximum Faradaic efficiency of 97% (at -0.8V vs RHE) and an NH3 yield of 21mg h-1 cm- 2, from an industrial wastewater level of 500ppm NO3 -. In situ electrochemical experiments indicate that Pd particles with 2.88nm can promote NO3 - hydrogenation to NH3 via well-modulated coverage of adsorbed H* species. Coupling the anodic glycerol oxidation reaction, ammonium and formate are successfully obtained as value-added products in a membrane electrode assembly electrolyzer. This work provides a feasible strategy for obtaining size-dependent H* intermediates for hydrogenation.

In Situ Combustion Characteristics of Heavy Oil in the Liaohe Oilfield at Different Temperatures

This study conducted in situ combustion oxidation experiments on crude oil from Block D within the Liaohe Oilfield, utilizing a kettle furnace low-pressure oxidation reaction method at various temperatures. The molecular composition of oxidation products was analyzed using gas chromatography–mass spectrometry (GC–MS) and high-resolution mass spectrometry. The results reveal that the molecular composition of the products remains relatively stable up to 300 °C, exhibiting a slight increase in C13-C30 alkanes. The ratio of the peak area for C21 to bisnorhopane is 0.082. From 300 °C to 450 °C, compounds with long alkyl chains gradually undergo thermal cracking, resulting in a significant increase in the production of alkanes within the C10–C30 range. The concentration of saturated hydrocarbons produced through thermal cracking reaches its maximum at a temperature of 400 °C. The most abundant peak of n-alkane is observed at C21, with a quantified ratio of peak area for C21 to bisnorhopane at 6.5, indicating a two-order magnitude increase compared to crude oil. From 500 °C to 600 °C, compounds undergo more profound thermal cracking and condensation processes. The predominant hydrocarbons consist of aromatic molecules containing two to six rings substituted with short side chains. The double bond equivalent (DBE) values of carbazoles and carboxylic acids are determined as 30 and 25, respectively. At 600 °C, the peak area ratio of naphthalene to biodecane is 300, indicating a remarkable increase of five orders of magnitude compared to the crude oil. The present study elucidates the correlation between the characteristics of combustion components in crude oil and the corresponding combustion temperature. Primary cracking reactions within crude oil are promoted effectively when keeping the combustion zone at 350 °C and 450 °C. This process significantly reduces the viscosity of heavy oil and enhances its fluidity.

Improved midgap recombination lifetimes in GaN crystals grown by the low-pressure acidic ammonothermal method

To investigate the carrier recombination processes in GaN crystals grown by the low-pressure acidic ammonothermal (LPAAT) method, the photoluminescence (PL) spectra and PL lifetimes of LPAAT GaN crystals grown on acidic ammonothermal (AAT) GaN seed crystals were correlated with the growth polarity and species/concentration of point defects. The PL spectra of LPAAT GaN grown toward the (0001¯) direction (−c region), which provided the highest growth rate, exhibited a predominant near-band edge (NBE) emission. Neither bandgap narrowing nor Burstein–Moss shifts due to high concentration residual impurities were observed in the NBE emissions, indicating higher purity than the previously reported AAT GaN crystals. In addition, strain-induced energy shift or energy broadening of excitonic emission peaks was not observed, indicating excellent crystal coherency. Because of the reduced concentration of midgap recombination centers, a record-long room-temperature PL lifetime for the NBE emission of ammonothermal GaN (40 ps) was obtained from the −c region. Meanwhile, the PL spectra also exhibited the yellow and blue luminescence bands originating from particular deep-state radiative recombination centers. The major vacancy-type defects acting as midgap recombination centers are identified as vacancy complexes comprising a Ga vacancy (VGa) and a few N vacancies (VN), namely, VGa(VN)n buried by H and/or O, where n is an integer. Further reduction of such defect complexes will allow less compensated stable carrier concentration in the LPAAT GaN crystals.

Contribution of graphene oxide (GO)-containing polydimethylsiloxane (PDMS) binder to the surface modification of electrospun PVDF membrane towards development of photothermal vacuum membrane distillation (PVMD)

Given the scarcity of water and energy resources and their potential to escalate into future crises, water and energy have emerged as the paramount challenges of the present century. To address these challenges, simultaneously, a novel membrane distillation (MD) technique named photothermal MD (PMD) has come to the forefront in recent years. The PMD is rapidly advancing, particularly in the field of desalination, towards increasing the use of sustainable solar energy. In this work, the surface of poly(vinylidene fluoride) (PVDF) electrospun membrane was turned into a photothermal surface by binding graphene oxide (GO) nanosheets using a binder solution made of polydimethylsiloxane (PDMS) with different concentrations (0.1, 0.5, 1, 2, 3 wt%). Subsequently, the environmentally-friendly low-pressure plasma polymerization method was employed to polymerize perfluorodecyl acrylate (PFDA) monomers on the surface of coated electrospun membrane to achieve an omniphobic surface. In this regard, the contact angles of water, oil, and ethanol/water (70/30 v/v) solution on the surface of the coated membranes were measured to be 144°, 124.4°, and 120.8°, respectively. Compared to the uncoated electrospun membrane, the one coated with GO-containing binder solution with optimum PDMS concentration of 0.1 wt%, showed a significant increase in flux by 41 % at 1 sun irradiation during photothermal vacuum MD (PVMD). In the PVMD process, the conventional method of feed heating was substituted with membrane surface heating utilizing solar energy. Additionally, vacuum was employed to facilitate the passage of water vapor through the membrane pores. This increment was further highlighted by salt rejection remained constant at 99.9 %. It was also found that PDMS concentration in the GO-containing binder solution adversely affects the membrane efficiency, exhibiting a decreasing trend from 54.1 % to 17.5 % when PDMS concentration increases from 0.1 to 3 wt%. Additionally, the long-term performance assessment of the prepared membrane coated with the binder solution with optimum PDMS concentration of 0.1 wt% demonstrated its acceptable resistance against wetting by the NaCl aqueous solution (35 g/L) containing 0.3 mM sodium dodecyl sulfate (SDS).

Air Purification Performance Analysis of Magnetic Fluid Filter with AC Non-Thermal Plasma Discharge

Air pollution caused by particulate matter (PM) is a worldwide concern. PM is particularly problematic from fossil-fuel-based energy conversion devices. For PM collection, a low-pressure loss method is ideal. Although PM collection via electrostatic force is an effective method with low pressure loss for PM with a wide range of diameters, it is difficult to apply to low-resistive PM, such as diesel particulates, owing to re-entrainment on the collection electrode. A magnetic fluid filter with an AC non-thermal plasma discharge solves the problem of re-entrainment. Based on our previous study, we hypothesized that an increase in the number of magnetic fluid spikes leads to an improvement in collection efficiencies with energy conservation. In this study, experiments are performed to verify this hypothesis. By improving our previous experimental methodology, the experiments include not only collection efficiency but also pressure loss, power consumption, and ozone generation efficiency. PM collection efficiencies using diesel fine particles and the ozone generation efficiencies required for air purification are investigated under different discharge conditions. The results revealed that the PM collection and ozone generation efficiencies increase proportionally with the number of spikes of the magnetic fluid with discharge, as hypothesized. The resulting PM collection and ozone generation efficiencies are sufficiently high for air purification.

Analytical method development and validation of antifungal drugs in updated ointment formulation using UV spectroscopy and RP-HPLC

A precise, simple, and validated Reverse-phase high-performance liquid chromatography (RP-HPLC) method alongside spectrophotometric analysis has been established for the simultaneous quantification of clobetasol propionate, miconazole nitrate, and salicylic acid in an updated ointment formulation. The impact of organic modifiers on the retention of the target compounds was assessed. The chromatographic analysis was conducted using a simple low-pressure gradient method with UV detection at 282 nm on a C18 column (5 ?m, 4.6 ? 250 mm HSS). The mobile phase consisted of a mixture of methanol, acetonitrile, and tetra ethylamine acetate buffer at pH 4, adjusted with acetic acid in a 40:40:20 v/v ratio, at a flow rate of 1.2 mL min-1. The method demonstrated linearity in the 5-15 ?g mL-1 concentration range for clobetasol propionate, 30-90 ?g mL-1 for miconazole nitrate, and 15-45 ?g mL-1 for salicylic acid. The limits of detection and quantification were determined to be 1.49 ?g mL-1 and 4.53 ?g mL-1 for clobetasol propionate, 8.72 ?g mL-1 and 26.43 ?g mL- 1 for miconazole nitrate, and 3.37 ?g mL-1 and 10.22 ?g mL-1 for salicylic acid, respectively. The recoveries for drugs in formulation range from 95 % to 99 %.

Improvement of fluorine attack induced word-line leakage in 3D NAND flash memory

In this work, the influence of fluorine (F) erosion on tungsten (W) gate process is studied, and the measure to mitigate the word line (WL) leakage resulting from F erosion in 3D NAND flash memory is proposed. As the number of layers in 3D NAND increases, the tungsten (W) gate word line (WL) layer fill process becomes more challenging in the post-gate process. As the fill path length increases, the tungsten gates become more susceptible to voiding during deposition, resulting in the accumulation of fluorine (F) by-products, and causing fluorine attack issues. In particular, under the influence of subsequent high-temperature processes, the by-products containing fluorine can diffuse into the surrounding structure and corrode the surrounding oxide layer. This leads to WL leakage, thereby affecting device yield and reliability. This paper begins by analyzing the microscopic principles of fluorine erosion in 3D NAND. We also propose a low-pressure annealing method to address the issue of fluorine erosion. Then, we conduct the experiments on annealing planar thin film stacks and 3D filled structures under atmospheric condition and low-pressure condition. We use various methods to characterize the concentration and distribution of residual fluorine elements. The experimental results demonstrate that under appropriate conditions, the residual fluorine in the tungsten gate can be effectively released by low-pressure annealing, thus reducing the leakage index of the word line. Additionally, as the outer CH is closer to the fluorine discharge channel, the influence of low-pressure annealing on the outer CH is more pronounced than on the inner CH. The low-pressure annealing can significantly reduce the fluorine content in the tungsten gate. This method can also mitigate the issue of fluorine attack oxides and reducethe WL leakage. Using low-pressure annealing treatment can also enhance the quality of 3D NAND flash technology.

Catalytic and non-catalytic low-pressure hydrothermal liquefaction of pinewood sawdust, polyolefin plastics and their mixtures

Hydrothermal co-liquefaction of biomass and polyolefin plastic feedstocks offers the advantage of potential synergistic reaction environments for producing liquid products of high fuel quality. In this present study, hydrothermal liquefaction and co-liquefaction of sawdust, low-density polyethylene and high-density polyethylene were investigated in a batch reactor from 350 °C to 450 °C and autogenic pressures below 30 bar. The novel low-pressure hydrothermal processing method was carried out with and without low-cost Ni–Cu/Al2O3 bimetallic catalyst. Thermal degradation of the sawdust started at 350 °C, whereas the plastics could only completely degrade at 450 °C, which was then chosen as the optimum reaction temperature. The catalysed process led to an increase in oil yield from the sawdust, with carbon enrichment by 16.3% and 22% deoxygenation. Furthermore, the catalyst promoted the formation of ketones and aromatic hydrocarbons, while consuming phenols and furfural in the sawdust-derived bio-oils. For the plastics, the catalyst, gave slight decreases in oils yield in favour of gas and/or char formation, with the promotion of in situ hydrogenation to enhance the yields of alkanes over alkenes. Results from hydrothermal co-liquefaction tests showed that synergistic interactions occurred between the degradation products of sawdust and the plastics. The observed synergy was further promoted by the presence of the catalyst, leading to dramatic deoxygenation of the oil products to produce hydrocarbon-rich fuels with less than 4 wt% oxygen contents (≈90% deoxygenation). This low-pressure hydrothermal co-liquefaction process is an efficient and cost-effective pathway for single-loop conversion of widely available biomass and plastics feedstocks into highly deoxygenated oils for use as sustainable fuels.

A Novel Low-Pressure Release Method Based on Inlet Regulation for Users with Low Demand Scenario

A Novel Low-Pressure Release Method Based on Inlet Regulation for Users with Low Demand Scenario

Ozone-assisted combustion and emission control in RCCI engines: A comprehensive study

This paper presents an investigation into the combustion and emission characteristics of reactivity-controlled compression ignition (RCCI) engines using ozone seeding, which is known as one of the most highly oxidizing chemical species. The study aims to address challenges pertaining to combustion control and emissions deterioration. Therefore, the current work investigates the RCCI mode of operation in a single-cylinder diesel engine with intake air that has been seeded with ozone by introducing conventional diesel fuel as a high-reactivity fuel using a high-pressure direct injection method and iso-octane as a low reactivity fuel using a low-pressure port injection method. In the experimental study, different ozone concentrations up to 300 ppm and three different energy-based premixed ratios of low reactivity fuel from 0% to 45% with a 15% rise rate were examined under various engine loads and constant engine speed. The methodology used in this research provided for simultaneous decreases in unburned hydrocarbon (HC) emissions and smoke opacity for RCCI engines. According to the experimental findings, simultaneous utilization of RCCI mode and ozone seeding led to a decrease of up to 36% in HC emissions and a reduction of up to 98.7% in smoke opacity. Moreover, nitrogen oxides (NOx) emissions were reduced by up to 39.5% at 20% engine load, whereas carbon monoxide (CO) emissions exhibited a decrease of up to 46% at 60% load. The RCCI mode also yields significant reductions in pollutant emissions and notable increases in brake thermal efficiency (BTE) when compared to the conventional diesel mode (CDM). In conclusion, this experimental study presents a promising solution for addressing emissions deterioration in RCCI engines while simultaneously achieving reductions in pollutant emissions.

Purification of Food Allergens from Their Natural Sources: Chromatographic Methods.

Isolation of food allergens from natural sources enables their characterization in a naturally occurring state. Low-pressure liquid chromatographic methods can be used to purify such allergens with high purity and yield. In this chapter, we describe the protocol for isolating a nut seed protein from its natural source. Interfering macromolecules such as fats and carbohydrates are removed followed by solubilization and extraction of nut seed proteins. The target protein is purified using a combination of various chromatographic techniques.

Effect of external magnetic field and dust grains on the properties of ion-acoustic waves

An experimental study to investigate the effect of an external magnetic field on the propagation of ion-acoustic waves (IAWs) has been carried out in hydrogen plasma containing two-temperature electrons and dust grains. It is a first step in understanding the propagation properties of IAWs in such an environment. A low-pressure hot cathode discharge method is chosen for plasma production. The desired two-electron groups with distinct temperatures are achieved by inserting two magnetic cages with a cusp-shaped magnetic field of different surface field strengths in the same chamber. The dust grains are dropped into the plasma with the help of a dust dropper, which gain negative charges by interacting with the plasma. The IAWs are excited with the help of a mesh grid inserted into the plasma. A planar Langmuir probe is used as a detector to detect the IAWs. The time-of-flight technique has been applied to measure the phase velocity of the IAWs. The results suggest that in the presence of a magnetic field, the phase velocity of IAWs increases, whereas introducing the dust particles leads to the lower phase velocity. The magnetic field is believed to have a significant effect on the wave damping. This study will aid in utilising IAWs as a diagnostic tool to estimate plasma parameters in the presence of an external magnetic field.

Investigation of the Indium migration mechanism in the growth of InGaN quantum wells by MOCVD

Improvement of InGaN quantum wells (QWs) with high In content is crucial for realizing well GaN-based optoelectronic devices, such as laser diodes (LDs) and light-emitting diodes (LEDs). In this paper, the migration mechanism of In atoms and its impact on the luminescence properties of green QWs are studied, and the material and optical quality of high-In-content InGaN QWs can be improved by increasing the Indium migration ability through low-pressure growth method. The experimental results show that the In incorporation into InGaN QWs decreases while the luminescence property increases with the decrease of growth pressure when the growth process is under the surface-reaction-controlled mode. The analysis of the evolution behavior of InGaN/GaN interfaces through TEM measurements reveals that the migration ability of In atoms is a key factor affecting the continuity of InGaN QWs and the formation of In aggregation. Further temperature-dependent photoluminescence (TDPL) analysis and theoretical investigation on the LSE model confirm that the improvement in the luminescence efficiency of QWs is attributed to the enhancement of interface quality and the weakening of localized states. These results provide a new technical direction for the development of high-performance LEDs and LDs.

A dilute-and-inject low-pressure gas chromatography-tandem mass spectrometry method for phthalate determination in extra virgin olive oil.

The goal of this study was to develop a method for the determination of nine phthalic acid esters in extra virgin olive oils using low-pressure gas chromatography-triple-quadrupole mass spectrometry. Sample preparation was simple, environmental friendly, and rapid inasmuch that it involved only dilution(<1mL of hexane). The low-pressure gas chromatography analyses were performed by using a 5 m wide-bore column. The limit of quantification for the phthalates ranged from 0.06 to 1.14mg kg-1 . Both intra- and interday precisions were measured, with coefficient of variation values ranging from 0.2% to 11.7%. The trueness of the method was measured by evaluating accuracy at the initial stage of the work and after 2 months, with values ranging between -8.7% and 12.1%. Moreover, blind accuracy was comprised between -11.6% and 14.2%. The method involves the use of simplified instrumentation and reduced analysis times (nearly two times faster) compared to a previously published comprehensive two-dimensional gas chromatography-triple-quadrupole mass spectrometry method, leading to a reduction of energy and helium consumption. The approaches were compared in analytical terms and for the environmental impact. In total, 23 olive oil samples were analyzed, with at least one phthalate detected in all but one sample.

Application of Ultrasonic Methods for Evaluation of High-Pressure Physicochemical Parameters of Liquids

An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by parallel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1–660 MPa, and temperatures 3–30°C. Isotherms of acoustic impedance Z_a, surface tension σ and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30°C. The results obtained in this study are novel and can be applied in food, and chemical industries.

Effects of Different Cooking Methods on Glycemic Index, Physicochemical Indexes, and Digestive Characteristics of Two Kinds of Rice

Diets including rice and rice-cooking methods influence digestive processes and blood glucose control. In this research, the effects of three different treatments (high-temperature and low-pressure plasma cooking, high-temperature cooking at atmospheric pressure (traditional method), and high-temperature cooking at high pressure) on the texture, color, molecular structure, infrared spectrum, microstructure, debranching enzyme activity, amylopectin content, glycemic index (GI), and in vitro starch digestibility of two rice varieties were studied. The results showed that the hardness, elasticity, viscosity, and chewability of rice after the high-temperature and low-pressure plasma treatment had no obvious changes compared with the traditional cooking method. A SEM analysis showed that the physical properties of the hydrophilicity on the surface of the rice increased after the high-temperature and low-pressure plasma treatment; the debranching enzyme activity reached 3.88 U/g (Xiantao rice) and 3.81 U/g (Heyuan rice), respectively, the amylose content of raw rice reached 68.77 mg/mL (Xiantao rice) and 64.92 mg/mL (Heyuan rice), which increased by 43.31 mg/mL and 39.46 mg/mL, respectively, and the GI was within the medium glycemic index of 56–69. The resistant starch in the Heyuan and Xiantao rice varieties amounted to 88.60 ± 3.10% and 89.40 ± 3.58%, respectively, after the high-temperature and low-pressure plasma processing method. The results showed positive effects and application potential for the cooking method in respect of diabetic consumers.

Mathematical model of astaxanthin purification process using the low-pressure column chromatography method

Astaxanthin is an antioxidant compound that can be extracted from the microalgae Haematococcus pluvialis using the microwave-assisted extraction (MAE) method. Purification of the astaxanthin compound can be conducted using a low-pressure column chromatography (LPCC) method. However, the mathematical model illustrating the adsorption and desorption process using the LPCC method has not been built by the other authors yet. Therefore, the purposes of this study were (1) to build the mathematical model of the purification process using the LPCC method, and (2) to simulate the experimental data using the model to find the important kinetic constant values that can be used in the industrial scale-up in the future. The purification process was carried out with silica gel as a stationary phase and a mixture of n-hexane:acetone of 3:1 (v/v) as a mobile phase. The silica gel diameter was varied to 0.2–0.5 mm and 0.063–0.2 mm, while the eluent velocity was varied to 1.85 mL/min and 3 mL/min. The mathematical model having five kinetic constants of De1, De2, kc2, kc2.a, and H_A2 was successfully built. The De1 and De2 (m2/s) were the effective diffusivities of astaxanthin in the intraparticle direction of the adsorbent granule and in the axial direction of the column, respectively. The kc2 (m/s) was the mass transfer coefficient of astaxanthin from the solution to the adsorbent. The kc2.a (/s) was the volumetric mass transfer coefficient of astaxanthin from the solution to the adsorbent. The H_A2 (g silica gel/m3) was the Henry's constant for astaxanthin concentration at equilibrium at the liquid-solid interface. In the variation of silica gel diameter, the De2 value at the diameter of 0.2–0.5 mm was greater than that at 0.063–0.2 mm. However, the De1, kc2, kc2.a, and H_A2 values ​​were not affected by the different diameters. In the variation of eluent velocity, the kc2 and kc2.a values at 3 mL/min were greater than those at 1.85 mL/min. However, the De1, De2, and H_A2 values were not affected by the different eluent velocities.

Programmable Low-Pressure Chromatographic Sub-90 s Assay of Parabens in Cosmetics with Post-Column Chemiluminescence Detection

This work describes a new programmable low-pressure chromatography method with post-column chemiluminescence (CL) detection for the rapid and cost-effective determination of four parabens in cosmetic products. Elution of the target analytes was achieved using a programmable mobile phase prepared by implementing a linear solvent gradient protocol based on appropriate flow rate modulation of 2 MilliGAT pumps. A 5 mm monolithic C18 column was used to separate the parabens. Post-column reaction of the eluted parabens with an acidic Ce(IV)-rhodamine 6G (Rho 6G) medium was carried out by introducing a flow stream of the reactants into the column eluate. The light generated from the CL reaction was detected with a flow-through CL detector fabricated in-house. The whole sequence of operations (including sample injection, generation of the mobile phase, addition of the post-column reaction reagents and signal acquisition) was under full computer control. Various operational parameters (the mobile phase composition and gradient conditions, the CL reagents’ concentrations and flow rates and the length of the reaction coil) were studied. The method was validated and applied to the analysis of various cosmetic products. The proposed approach allows sub-90 s separation of the four parabens and their determination with a limit of quantification of 0.2 μg L−1 with a sample throughput of 24 samples h−1. In addition, the method is economical, makes use of low-cost low-pressure components, is fully automated and produces a low amount of waste.

Evaluation of the potential for distributed generation of green hydrogen using metal-hydride storage methods

This study presents methodology for the evaluation of appropriateness of a hydrogen generator for gas production in multiple distributed plants based on renewable energy sources. The general idea is to form hydrogen clusters integrated with storage and transportation. The paper focuses on the financial viability of the plants, presenting the results of economic evaluation together with sensitivity analysis for various economic factors. The analyzed case study proves that over a wide range of parameters alkaline electrolyzers show favorable economic characteristics, however, a PEM-based plant is more resilient to changes in the price of electricity, which is the main cost component in hydrogen generation. The study is enriched with an experimental investigation of low-pressure storage methods, based on porous metal hydride tanks. The effectiveness of the tanks (β) compared to pressurized hydrogen tanks, in the same volume and pressure is equal to β = 10.2. A solution is proposed whereby these can be used in a distributed hydrogen generation concept due to their safe and simple operation, without additional costly equipment, e.g., compressors. A method for evaluation of the avoided energy consumption as a function of the effectiveness of the tanks is developed. Avoided energy consumption resulting from implementing MH tanks equals 1.33 – 1.37 kWh per kilogram of hydrogen depending on the number of stages of a compressor. The methods proposed in this paper are universal and can be used for various green hydrogen facilities.