Feed Gas Research Articles

Value-of-Information Methods Assess Surveillance Data From Fields to LNG Plants

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215318, “Assessing the Value of Reservoir Surveillance Data From Gas Fields Producing to LNG Plants Using Value of Information,” by Daniel I. O’Reilly, SPE, Zhi Qui Xia, and Andrew R. House, Chevron. The paper has not been peer reviewed. _ A set of examples is shared in the complete paper for calculating the value of reservoir surveillance conducted in gas fields tying into liquefied natural gas (LNG) plants. The objective is to use existing value of information (VOI) methods to provide a means of justifying this reservoir surveillance, given that management of operating companies often is more inclined to agree to reservoir surveillance when its value is calculated clearly. Introduction The main objective in supplying gas to an LNG plant is to ensure that sufficient gas feed is available at all time scales (short-, medium-, and long-term). To forecast future gasfield performance, surveillance of producing reservoirs is required. The surveillance data are considered highly valuable by petroleum engineers, but a quantitative value is not always calculated. Oil and gas engineers have considered VOI when gathering field-appraisal information for some time. Many concepts were originally borrowed from the financial industry. Two potential decisions can be identified when deciding on reservoir surveillance in producing fields: what surveillance data to obtain and, if applicable, how frequently the data should be obtained. This may influence the total cost of obtaining the data, along with its reliability. Problem Statement LNG plants normally are designed with a lifespan of several decades, and gas fields must supply at the plant capacity over this period. It is common for different fields to be developed sequentially over the life of the plant. It is crucial that new fields are brought online before producing fields can no longer meet plant demand. In the medium to long term, continuous withdrawal of gas from the reservoir means that its pressure and gas deliverability decline. Initially, gasfield potential is much higher than plant demand, and often this allows for reservoir surveillance at no cost. Many operating companies favor bringing online a new field once minimum excess wellhead capacity is met (i.e., earlier than when gas supply equals plant demand). The offshore gas-rate potential normally is not directly measurable because production is constrained at the maximum rate of the LNG plant; it is a calculated value and subject to uncertainty. Well potential is calculated after the hydraulic performance of the reservoir and wellbore are fully characterized. Reservoir surveillance data are required as inputs to these calculations. In the short term, problems may occur with the near-wellbore formation, well, tree, or subsea infrastructure that could cause reduced flow rates or require the well to be shut in. The likelihood of all production risks can be estimated using reservoir surveillance data. Commonly, reservoir surveillance events are executed during planned or unplanned plant downtime. This avoids a situation in which plant capacity is underused because of a well being shut in for surveillance. However, many situations exist in which surveillance may require an investment or production well downtime. In these cases, an actual cost is incurred that must be evaluated. The objective of the complete paper, therefore, is to use VOI to quantify the value of reservoir surveillance data.

HYDROGEN GAS RECOVERY THROUGH THE PERMEATION MEMBRANE BASED BIMETALLIC PALLADIUM ALLOY

Generally, the H2 gas produced from the industrial processes is not in a pure state but is mixed with other compounds. For example, the off-gas produced in the oil refinery process still contains CH4, H2, and other gases. Thus, the process of separating as well as recovering the valuable H2 gas from other gas compounds is of essential process. Currently, the H2 separation process is being developed with relatively low costs with good efficiency, namely using the permeation membranes separation process, in which the compounds with high permeability tends to be more easily separated. Here we report the hydrogen recovery process from the mixed H2/N2 off-gas contains 61 % hydrogen and 39% balancing nitrogen, by using the bimetallic Pd-Ag membrane, where the effect of the gas feed pressure (1 and 2 bar) and operating temperature (373.15, 423.15, 473.15, and 523.15, 573.15 K) on the resulting permeate flux is comprehensively studied. We found that the flux and permeability increased with the increase in the gas feed pressure and temperature. Under the same gas temperature of 373.15 K, the permeation flux at the 2 bar gas feed pressure was found to be 2.047 mol.s-1.m-2, which was 166% greater than that of 1 bar pressure, i.e. 1.204 mol.s-1.m-2. Meanwhile, under the same gas feed pressure of 2 bar, the permeation flux at the operating temperature of 573.15 K was found to be 2.103 mol.s-1.m-2, which is 104,9% greater than that of 373.15 K operating temperature, i.e. 2.047 mol.s-1.m-2. These findings suggest the breakthrough advantages of the Pd-Ag alloy membrane for its high hydrogen permeability at low pressure.

A numerical comparison of heavy‐purge and dual‐reflux strategies in pressure swing adsorption for methane enrichment

AbstractDual reflux pressure swing adsorption (DR‐PSA) has been regarded as a state‐of‐the‐art adsorption‐based process which can simultaneously obtain two streams of pure product gases with a narrow pressure window. However, the DR‐PSA has not yet been reported in industrial applications. Herein, a DR‐PSA and a heavy‐purge pressure vacuum swing adsorption (HP‐PVSA) were numerically investigated for the enrichment of 1%, 8% and 15% CH4 from N2 gas mixtures in pilot‐scale. Key separation indicators such as purity, recovery and energy cost of the two cycles were compared to analyze the limitations of the DR‐PSA process while scaling‐up. This study reveals the impact of heavy to feed (H/F) ratios on purity and recovery for both cycles and analyses the energy consumption of each process. For feed gas with 15% CH4, while DR‐PSA can achieve a slightly better purity and recovery (88.3% and 88.3%, respectively) compared to HP‐PVSA (87.5% and 80.3%, respectively), it also involves an order of magnitude higher energy consumption (181.6 versus 24.6 kJ/mol CH4 captured). DR‐PSA shows significantly superior performance than HP‐PVSA when the CH4 content in the raw feed gas is low. Under the investigated operating conditions, HP‐PVSA can only enrich 1% CH4 to 10% with 78.7% recovery while DR‐PSA can obtain 75.3% purity and 77.3% recovery. Results indicate that DR‐PSA exhibits superiority in enrichment of dilute gas, however, its high energy consumption, high capital expenditures and limitations in processing high throughput are the chief reasons hindering its industrial application.

New Modeling Approaches for Ethylene Oxychlorination in Fluidized Bed Reactors: Industrial and Low Flow Rate Conditions

A simple model (Continuous Stirred-Tank Reactor) has been developed to predict the behavior of industrial ethylene oxychlorination fluidized beds operating in a turbulent regime. The approach showed good agreement both with results from industrial reactors and with those corresponding to the (Simple two phases-Plug bubble-Mixed flow emulsion approach) validated in the literature. For low flow rates, the use of the (Simple two phases - Plug bubble - Plug emulsion model) adapted to these conditions enabled us to highlight the location and extent of undesirable thermal hot spots for the process, and to propose actions to control them by acting on the temperature and/or on the feed gas flows. By comparing this model with the plug approach, the significant slowdown in ethylene conversion caused by resistance to mass transfer when feed flow rates are low is highlighted. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Improving water management in gas diffusion layers through the optimization of carbon composite microporous layers

Using the Washburn method, the wettability of microporous layer (MPL)-coated carbon-felt gas diffusion layers (GDLs) with liquids with different polarities were studied using process tensiometry. The Washburn approach allows us to study fluid uptake into the electrode pores through capillarity and the resulting liquid-solid internal contact angles. Interpretation using the Owens-Wendt analysis reveals the effects of varying proportions of hydrophobic poly(tetrafluoroethylene) (PTFE) and multi-walled carbon nanotubes (MWCNTs) in the MPL yielding solid-vapor surface energies. An optimal MPL contained a 10 wt% MWCNT/KJB carbon substrate and 10 wt% PTFE loading. This information was corroborated by evaluating these materials in anion exchange membrane fuel cells with simultaneous gas and aqueous electrolyte feed.

Retrofit of a Marine Engine to Dual-Fuel Methane–Diesel: Experimental Analysis of Performance and Exhaust Emission with Continuous and Phased Methane Injection Systems

Shipping is a highly energy-intensive sector, and fleet decarbonization initiatives can significantly reduce greenhouse gas emissions. In the short-to-medium term, internal combustion engines will continue to be used for propulsion or as electricity generators onboard ships. Natural gas is an effective solution which can be used to mitigate greenhouse gas emissions from the marine sector. Considered to be a transitional fuel, it can provide a potential reduction in CO2 emissions of around 20–30%, compared with conventional marine fuels. This work investigated the influence of diesel-injection strategies on the performance and emissions of a single-cylinder prototype compression-ignition engine for marine applications, retrofitted to run as a Low-Pressure Dual-Fuel Engine using natural gas. Two different injection systems were used: a mass flow controller enabling continuous-mode gas feeding, and a Solenoid-Operated Gas Admission Valve for marine applications, the latter allowing phased natural-gas injection. Experimental tests were focused on partial-load conditions, which are critical for dual-fuel engines, with a natural gas/diesel mass ratio of 4:1. Phased injection resulted in reductions in fuel consumption, compared to continuous mode, of up to 11%. Further experiments demonstrated reductions in fuel consumption of up to 20.7% (in equivalent diesel); on the other hand, the unburned hydrocarbon emissions which resulted were an order of magnitude larger than the reference values for full diesel, reducing the benefits in terms of greenhouse gas emissions, with a reduction in Global Warming Potential of only 3% compared to full diesel.

Performance improvement of the H2 shaft furnace: A numerical study on hot-charge operation

This work proposes a retrofitted gas feed system for increasing thermal energy supply when the hydrogen-operated direct reduction shaft furnace adopts hot-charge operation. The potential of the new feed system is assessed further using a two-dimensional computational fluid dynamics model. The results show that the ascending gas is heated up quickly by the descending hot solid within a narrow uppermost zone when employing the conventional gas feed system, so the opportunities to obtain better furnace performance are limited since the thermal energy of the hot solid leaves the furnace in the form of high-temperature off-gas. Under a scenario adopting the hot-charge operation in conjunction with the new feed system, a high temperature favoring the endothermic reactions is maintained within almost the entire upper part of the furnace. Using an appropriate upper-row gas feed rate, the overall furnace performance can be substantially improved particularly with respect to final solid reduction degree.

Experimental and thermodynamic modelling of hydrate dissociation conditions for CO[formula omitted] + propane mixtures

The possibility of hydrate formation poses a central issue for Carbon Capture and Storage (CCS) and Enhanced Oil Recovery with Water-Alternating-Gas (EOR/WAG) injection projects. In most of the cases, however, the available fluid for this purpose consists of a CO2-rich stream containing contaminants such as hydrocarbons and permanent gases. As a result, there is a growing interest in evaluating the effect of small impurities concentrations on the phase behaviour of such streams. This work investigates the impact of propane as a promoter in carbon dioxide hydrate formation, covering a concentration range in the feed gas phase between 10 and 69% on mole basis. The study also considers the Lw-LCO2-H region, taking into account liquid and supercritical transportation commonly encountered in CCS projects. Additionally, a procedure to estimate uncertainties in the graphical determination of the dissociation temperature and pressure is discussed. The thermodynamic modelling approach includes three different modifications of cubic equations of state (CEoS): asymmetric mixing rule, advanced Huron-Vidal mixing rule, and cubic-plus-association approach. An alternative procedure based on setting different sets of CO2 Kihara’s parameters when shifting between structures was also used. While satisfactory average temperature deviations were obtained for those equations of state, maximum deviation between calculated and experimental temperatures spanned from 0.5 to 2.5 K, depending on the thermodynamic model.

Enhancing Tribological Characteristics of Titanium Grade-5 Alloy through HVOF Thermal-Sprayed WC-Co Nano Coatings by TOPSIS and Golden Jack Optimization Algorithm.

Thermal spray coatings have emerged as a pivotal technology in materials engineering, primarily for augmenting the characteristics related to wear and tribology of metallic substrates. This study aimes to delve into applying High-Velocity Oxygen Fuel (HVOF) thermalsprayed WC-Co nanocoatings on Titanium Grade-5 alloy (Ti64). The coating process, utilizing nano-sized WC-Co powder, undergoes systematic optimization of HVOF parameters, encompassing the flow rate of carrier gas, powder feed rate, and nozzle distance. Experimental assessments via Pin-on-Disc (PoD) tests encompass Loss of Wear (WL), Friction Coefficient (CoF), and Frictional Force (FF). Later, an exhaustive optimization of responses is conductede using the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) method and the golden jack optimization algorithm (GJOA). Outcomes show a substantial increase in WL, CoF, and FF with a rise in the carrier gas and powder feed rate. However, with increasing spraying distance of powder, the WL, CoF, and FF tend to lower due to higher bonding, which leads to increased wear resistance. The ideal parametric settings achieved from TOPSIS and GJOA are 245 mm of spray distance, 30 gpm rate of powder feed, and 11 lpm of carrier gas flow rate. The powder feed rate contributes 88.99% to the control action, as seen from ANOVA. The confirmation experiment presents that the WL, CoF, and FF output responses are 42.33, 27.97, and 9.38% less than the mean of experimental data. These results highlight the HVOF process in spraying WC-Co nanocoatings to fortify the durability and performance of Ti64 alloy that can be patented for diverse engineering applications.

Study on the Synergistic Effect of SiO2 and H2O on Oxidative Coupling of Methane over Mn-Na2WO4/SiO2 Catalyst.

Mn-Na2WO4-based catalysts with different supports were prepared using the incipient wetness impregnation method and evaluated for their oxidative coupling of methane (OCM) reaction performance. The results demonstrated that the SiO2- supported catalyst exhibited the best catalytic performance, and the introduction of H2O further enhanced its activity. Under the conditions of a feed gas mixture of CH4/O2/H2O = 6:1:24 at 800 °C and atmospheric pressure, the CH4 conversion and C2+ selectivity over the Mn-Na2WO4/SiO2 catalyst increased from 28.4% and 77.4% (without H2O) to 33.2% and 84.9%, respectively. In contrast, the catalytic activity using TiO2 and MgO supports drastically declined. Characterizations using X-ray diffraction (XRD), in situ infrared spectroscopy (In-situ IR), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), and oxygen temperature-programmed desorption (O2-TPD) revealed that the introduction of steam not only served as a diluent to decrease the partial pressures of the reactants CH4 and O2, thereby reducing deep oxidation reactions in the gas phase, but also interacted with surface oxygen species (O2 2-) and silica to form adjacent surface-bonded disilanol free radicals Si-OIH. This interaction facilitated the dehydrogenation and coupling of two methane molecules on the catalyst surface, resulting in the generation of C2+ products, significantly enhancing the catalytic activity and selectivity of OCM.

Complete degradation of propranolol by a water falling film non-thermal plasma reactor: The effects of input power and plasma gases on transformation pathway

Propranolol, a beta-blocker, is a widely used drug for cardiovascular diseases. A synthetic sample containing propranolol (PRO) solution at native pH was recirculated up to ten times through an original coaxial non-thermal plasma reactor with a water falling film. Different discharge conditions, feed gasses, and power greatly influenced the extent of PRO degradation and the abundance of degradation products. The highest degradation rates were achieved in Ar plasma, either pure or in a mixture with O2, with over 70% of PRO degraded after only two passes through the DBD reactor. The full non-thermal plasma treatment was followed by a minimal change of pH value and conductivity. On the other hand, ambient air as the feed gas resulted in 60% of PRO degradation rate after the full treatment and contributed to a major drop in pH value and an increase in the conductivity of the treated solution. The structures of 47 degradation products in all three gases were identified and the degradation pathway is proposed, supported by DFT methodology. Scavenging experiments demonstrated that hydroxyl radical was predominant when plasma was generated using ambient air and Ar, while it had a minimal effect on the degradation in the mixture of Ar and O2. The desired level of propranolol decomposition was achieved only by the adjustment of the nonchemical parameters of the treatment, such as plasma gas composition and power. These results imply that a non-thermal plasma reactor is a highly effective method for pharmaceutical wastewater treatment, with no catalysts added.

Ethane integration project—a study for Egyptian NGLs plants and their economics

For Egypt, ethane is a vital chemical precursor, with the potential to significantly attract financial resources and drive economic growth. Enhancing its added value necessitates efficient recovery of ethane before it enters the national grid without processing. This research investigates the technical and economic feasibility of integrating natural gas liquids (NGLs) from three Egyptian NGLs plants—South Western Desert NGLs (SWD NGLs), North Western Desert NGLs (NWD NGLs), and East Mediterranean NGLs (EMD NGLs)—to improve ethane recovery from natural gas fields. The study focuses on revamping these NGLs plants using various NGLs recovery techniques, conducting a comprehensive comparison to identify the most effective methods for processing rich feed gas. Detailed design of the NGLs recovery processes was developed using HYSYS V.14 simulation software and supplementary calculation sheets. The design criteria encompass both technical and economic parameters to ensure a holistic approach in meeting project requirements. Results indicate a significant increase in ethane recovery: 16% for SWD NGLs, 10% for NWD NGLs (A, B, C), and 85% for EMD NGLs. This improvement will boost ethane feedstock for petrochemical companies from 2000 ton/day to 3500 ton/day, enabling increased polyethylene production. Economic analysis for the base case shows an expected internal rate of return (IRR) of 26%, a net present value (NPV) of USD 73 million, and a payback period of approximately 3 years. Sensitivity analysis on product prices, feed gas prices, and total capital investment confirms the project’s economic viability, with all cases showing feasibility (IRR ≥ 15%) except when product prices fall below USD 225/ton for propane, USD 215/ton for liquefied petroleum gas (LPG), and USD 25/bbl for condensate. This study highlights the potential for enhanced ethane recovery, offering substantial economic benefits and supporting the growth of Egypt’s petrochemical industry.

Development of a Controlled Humidity Differential Electrochemical Gas Monitoring System

Lithium-air batteries (LABs) represent a promising future battery technology due to their high energy density, although several challenges hinder them from achieving their theoretical performance. These challenges include clogging of the porous air cathode by insoluble discharge products and high overpotentials during cycling [1, 2]. A recent proposal to address these issues involves the reversible formation and oxidation of LiOH in nonaqueous LABs. Of course, LiOH-based LABs require a proton source to form LiOH from the electrochemical reaction of oxygen and lithium ions [3]; humidity in air is an obvious choice for the proton source, making the relative humidity of LAB feed gas an important parameter to control and monitor during LAB electrochemical analysis.For LABs, galvanostatic charge/discharge coupled with quantitative gas evolution/consumption measurement is essential to understand the electrochemical processes during battery operation. Here, we report an advanced operando pressure measurement system that allows the control and monitoring of humidity in the cell headspace while also tracing overall gas consumption and evolution. Our gas handling system generates humid air using a water-containing chamber with a temperature control vessel to generate water vapor. A mass flow controller mixes dry air with humid air to generate specific relative humidity and send it to the cell. Using various low-volume in-line sensors, our system can track headspace humidity, temperature, and pressure within a custom-modified Swagelok-type cell. The total headspace volume must be small (~mL) since gas consumption occurs on a μmol scale in our lab-scale cells. To minimize headspace and dead volume within the Swagelok-type cell, a digital humidity and temperature sensor with exceptional accuracy was integrated into a customized printed circuit board (PCB). This PCB is attached to the small dead-volume Tee connection. To control the humidity inside the cell and achieve sensor data simultaneously, all sensors in the monitoring system are controlled by a LabVIEW program (National Instruments). To show the utility of this new system, we will present analyses of nonaqueous and solid-state LAB cells that operate at various humidities and current rates, while employing various known 2 e- and 4 e- oxygen reduction catalysts.

Spectroscopic Elucidation of Phase Evolution in NiO/YSZ Under Oxidative and Reductive Gas Environments

High temperature co-electrolysis of CO2 and H2O serves a viable, energy efficient, and scalable route to produce syngas (CO+ H2), which can be used to generate a variety of utility hydrocarbons. Solid oxide electrolysis cell (SOEC) has proven to be a promising technology for CO2 utilization and a carbon neutral route to curb CO2 emissions. The design of cathode catalyst is critical as it must facilitate the activation of CO2 and H2O and also exhibit high electronic and oxygen ion conductivity. The state-of-the-art cathode material used in SOECs is Ni/YSZ (8 mol% Yttria Stabilized Zirconia) ceramic composite (known as cermet), whose performance is dependent on various operating factors including temperature, composition of feed gas stream, presence of contaminants like SOx/NOx etc. There is a very limited number of studies on the evolution of the cathode materials under process level conditions. To begin with, effect of different oxidative and reductive gas environments and temperature over Ni/YSZ is studied using in situ Raman spectroscopy.Typical flue gas composition is chosen as the basis for the concentration of different components like 15% CO2, 10% H2O, 5% O2 with argon. Under oxidative conditions (O2, CO2, H2O) with temperature variation range of RT-800 0C, NiO/YSZ vibrational modes revealed that it is composed of NiO and YSZ phases. It is seen that there is thermal broadening in the bands of NiO and YSZ, thermal effects reversible upon cooling down and red shift in the NiO bands exemplified the lattice expansion. Exposing the NiO/YSZ to 5% H2 at high temperature resulted in the formation of metallic Ni, which is corroborated by the absence of the Ni-O vibrational modes in Raman spectrum at 400 0C. YSZ phase is quite stable in H2 at elevated temperature.After reduction of NiO/YSZ to get Ni/YSZ, exposure to oxidative environments (i.e., O2, CO2, H2O) aided in the formation of defect laden NiOx phase on YSZ. Specifically, NiOx formation starts at 350 0C under oxygen and at 450 0C under CO2 and H2O. Under 15% CO2, there is an overlap between the bands associated to the carbonate like species and the NiO phase but there is no formation of coke at these conditions as D and G bands were not observed (Fig. 1). It could be due to the oxidation of Ni that obliterated coke formation. The blue shift at 1046 cm-1 (2P mode of NiO) signifies the shortening of bond length in Ni-O with gradual conversion of Ni to NiOx. Compared to the NiOx phase formed under 5% O2 and 15% CO2 which has a sharp feature in Raman spectra, there is a broad band of NiOx phase formed under 10 % H2O in the region 480-580 cm-1 . This observation demonstrates the variation in the microcrystalline size of the defect laden NiOx phase formed under exposure to different oxidizers.Another set of experiments were done with the dry hydrogen (5 % H2) and humidified hydrogen (5% H2 + 10 % H2O) to study the role of presence of water on the reduction of NiO/YSZ with temperature variation between 120 – 800 0C. It was found that reduction of NiO to Ni is not affected by the presence of water. Under both conditions this transformation occurs between 400-600 0C. The results from the current study provide the key information on the effects of temperature and gas compositions over Ni/YSZ which serves as a guide for the process level design and operation of SOECs. References Juliana Carneiro et al, Industrial & Engineering Chemistry Research 2020 59(36), 15884-15893.John Kirtley et al, The Journal of Physical Chemistry C2013, 117 (49), 25908-25916.A. Naumenko et al, Phys Chem Solid State 2008, 9, 121–125. Figure 1

Parametric study of a vortex-enhanced supersonic inductive plasma torch

The feed gas injection configuration in radio-frequency (RF) inductively coupled plasma (ICP) torches plays a critical role in discharge stability, gas heating, and device thermal management: particularly if a supersonic nozzle is used to subsequently accelerate the hot gas. A novel injection configuration is the bidirectional vortex, which segments the internal ICP flow field into two counter-propagating vortices that can significantly enhance gas heating and reduce heat losses. The diameter of the interface between the vortices (known as the mantle) is expected to be an important dimensional parameter affecting torch operation, especially relative to the nozzle size. In this work, we investigate the effect of nozzle throat diameter on the behaviour and performance of a vortex-enhanced supersonic ICP torch. The system is operated at RF powers and argon mass flow rates between 200–1000 W and 0–400 mg s−1 respectively, and different nozzle diameters ranging from 1.5 to 4 mm are explored. Because of the high-temperature environment, and to prevent disruption of the vortex flow fields, non-invasive diagnostics are used to measure the gas temperature and plasma density, and to infer the torch thermal efficiency and achievable gas specific enthalpy change. The maximum temperature is between 8500–9500 K with the 1.5 mm nozzle giving the highest temperature for a given power and mass flow rate, while plasma densities vary between 1020–1021 m−3 depending on the operating conditions. The thermal efficiency increases from 29% for the 1.5 mm nozzle to just above 70% for the 4 mm nozzle with a similar maximum specific enthalpy of around 1.5 MJ kg−1. These results demonstrate the important coupling between torch properties, and how system optimization can lead to tailored performance of potential interest to several ground and space-based applications.

Modeling of hydrogen separation through Pd membrane with vacuum pressure using Taguchi and machine learning methods

The performance of hydrogen purification using palladium (Pd) membrane is analyzed by Taguchi and machine learning (ML) methods. Three system factors are considered: the feed gas mixture composition (i.e., H2, CO2, and H2O), retentate-side total pressure, and vacuum pressure. The Taguchi method designs the experimental cases based on the constructed orthogonal array. In addition, the hydrogen flux is investigated by the analyses of variance (ANOVA) and artificial neural networks (ANN) methods. The results show that the effects of the considered factors on the hydrogen permeation performance can be ranked as feed gas mixture composition > retentate-side total pressure > vacuum pressure. Both the retentate-side pressure and vacuum pressure present a positive effect on hydrogen flux. The average relative error of hydrogen flux between the experimental results and predictions by ANN is 2.1%, which proves that the ANN method is an effective technique for predicting the hydrogen flux through the Pd membrane. The ML classification test is then performed for hydrogen purity by three machine learning methods: decision tree (DT), support vector machine (SVM), and ensemble method. Among the various classification models, the Quadratic SVM model exhibits a relatively high average training accuracy but shows overfitting. However, the bagged model of the ensemble method can achieve an impressive training accuracy of 91.4% and a prediction accuracy of 85.7%.

Rapid susceptibility of Carbapenem resistant Pseudomonas aeruginosa and its resistance gene to non-thermal plasma treatment in a batch reactor

The critically ranked carbapenem-resistant Pseudomonas aeruginosa has been observed to infect immunocompromised patients that consume polluted waters, leading to critical infections and more hospital costs. To save lives and unburden the public health sectors of preventable costs, non-thermal plasma (NTP) technology was investigated as an alternative disinfection step that could be applied in wastewater treatment plants (WWTPs) to inactivate this bacterium and its prominent carbapenem resistance gene (blaNDM-1). Culture and molecular-based techniques were employed to confirm carbapenem resistance in P. aeruginosa (27853). Culture suspensions of carbapenem-resistant ATCC P. aeruginosa (16 h culture) were prepared from confirmed isolates and subjected to plasma treatment at varying time intervals (3 min, 6 min, 9 min, 12 min and 15 min) in triplicates. The plasma treated samples were evaluated for re-growth and the presence of blaNDM-1. The treatment resulted in a 0.68 log reduction after 3 min and the highest log reduction of ≥8 after 12 min, suggesting that plasma disinfection has a great potential to be an efficient tertiary treatment step for WWTPs. Moreover, the gel image showed that band intensity of blaNDM-1 reduced with treatment time, thereby suggesting a probable reduction of amplified genes. Notwithstanding, longer treatment time, a grounded electrode with a larger surface (≥ 40 mm diameter) and/or oxygen-containing feeding gas is warranted to completely inactivate its antibiotic resistance gene (ARG), which might be bound by biofilms as they seem to protect P. aeruginosa from the action of non-thermal plasma (NTP) disinfection.

Investigating the Irreversible Poisoning of Methanol Synthesis Catalysts – A Setup Construction Guide

AbstractWhen utilizing industrial exhaust gases for methanol synthesis, catalyst poisoning is an important issue. Long‐term in‐situ poisoning under industrially relevant conditions with sulfur‐containing molecules co‐fed into the feed gas flow and supplemented by extensive post‐mortem characterization of the catalyst bed is an efficient way to deepen the understanding of the poisoning mechanism and the different poisoning strengths of H2S, thiophene, and COS reported in literature. Unfortunately, such studies are rare due to the corrosive effects of sulfur compounds on typical lab‐scale flow setups. Therefore, this communication provides a detailed description of a setup built for poisoning studies using sulfur‐containing molecules under industrially relevant methanol synthesis conditions.

Joint experimental-computational: Revealing the role of sodium poly(heptazineimide) in the selective separation of CO2 in PEBAX-based mixed matrix membranes

Mixed matrix membranes (MMMs) with the dual properties of porous materials and polymer matrix membranes have become one of the most optimal solutions to the gas separation problem. However, the adapted porous material and the explicit transport mechanism of gases within the mixed matrix membrane hinder its further commercialization. Thanks to their porous nature and tunable gas adsorption properties, heteroatom-doped porous materials, especially nitrogen-doped porous materials, are widely used to design and prepare advanced CO2 separation membranes. Herein, a layered two-dimensional nano-sheet with a nitrogen content of 44.7 % was successfully synthesized via thermal polymerization. And nano-sheets were homogeneously dispersed in a Pebax matrix to make a composite film. Since the CO2 affinity of the nitrogen functional site and the PEO flexible chain, realizing the synergistic improvement of CO2 permeability and selectivity. A comprehensive combined permeation experimental/simulation characterization reveals the CO2 transport pathway within the membrane, indicating the mechanism of action of nitrogen-doped porous packing on CO2 diffusion. Among these, the CO2 permeability of the mixed matrix film containing 5 wt% sodium poly(heptazine imide) (NaPHI) reached 153 Barrer at a feed gas pressure of 9 bar, nearly 149 % compared to the pure Pebax film. The selectivity of CO2/N2 was enhanced to 105, exhibiting a remarkable increase of 159 % and exceeding the 2019 Robeson limit. Importantly, the present work further reveals and demonstrates the gas separation mechanism of nitrogen-doped porous filler/polymer hybrid matrix membranes, which provides new ideas for the design and application of heteroatom-doped porous fillers in the field of gas separation.

Combined steam and CO2 reforming of methane over Ni-based catalysts with spherical porous structure

Combined steam and dry reforming of methane (CSDRM) is expected to be promising when considered as a new alternative feedstock for F-T synthesis because it can produce high-quality syngas without carbon deposition. In this study, the support particle sizes were varied independently to assess their influence on the performance of the metallic Ni. The catalytic activity is most influenced by nickel particle size and distribution, and it has also been investigated for its significant role in the metal-support interaction. To perform CSDRM, the Ni-based catalyst was prepared by impregnation method on a spherical nano-silica support prepared by sol–gel method. The size of the spherical silica nanoparticles (40–300 nm) was controlled by varying the ethanol molar concentration; the spherical particles showed high performance on a uniform and evenly drawn support. In the 44 nm spherical silica catalyst, it was confirmed that the maximum dispersion increased to 21 % and the reducibility increased to 36 %. For stable synthesis gas production, various feed gas ratios (0.7:1.3:1.7) were established and the respective feed gas components (CH4, CO2 and steam) and reactions were investigated. Also, with the increase in the concentration of steam in the feed gas ratio, there was a significant increase in CO production. This trend was attributed to competing reactions occurring due to the side reactions (WGS↔RWGS; CO+H2O↔CO2 + H2) and was investigated with equilibrium constant values using thermodynamic equilibrium plot data. From the experimental results obtained, the catalyst showed high performance on a stable support and produced a stable H2/CO ratio of 2 for 100 h, without side reactions, at the feed gas ratio (CH4:CO2:H2O = 1:0.6:0.85).