Steam Flow Research Articles

Static and dynamic friction and wear of cobalt-based coatings at elevated temperatures

Advanced ultra-supercritical power plants, in which steam temperatures exceed 700 °C, demand the development of protective coatings, particularly for valves governing the steam flow where sealing surfaces are subjected to high static tribological solicitations. In this context, we systematically investigated the friction (static and dynamic) and wear of two cobalt-based coatings and one nickel-based substrate. Results indicate that oxidation kinetics exhibits a double-edged sword effect in terms of tribological properties at elevated temperatures. Fast oxidation kinetics promotes the sintering of oxides, generating a smoother oxide tribofilm and lowering the dynamic coefficient of friction (COF). However, this can also significantly increase the static COF over loading time due to welding/sintering of oxidized asperities, leading to increased torque requirements for valve operation.

Numerical Study on Effects of Nanoparticles Concentration and Steam Flow Rate on Oil Recovery from a Model Porous Medium

AbstractEffects of nanoparticle and steam injection on the extraction of Iranian American Petroleum Institute (API) 14 heavy oil from a model porous medium at temperatures of 110, 150, and 200 °C were investigated. Nanoparticle content was 1 %, 3 %, and 5 %, and injection flow rates were 0.018, 0.036 and 0.072 mL h−1. In short‐term injection, increasing the injection temperature to 200 °C and the flow rate to 0.072 mL h−1 resulted in the highest recovery. In the mid‐term injection, the highest recovery factor was at a temperature of 150 °C and flow rate of 0.036 mL h−1, while the results of the long‐term injection predicted a non‐monotonic effect of flow rate. The effect of alumina content on the recovery factor is less than that of temperature and flow rate. Interestingly, alumina content also has non‐monotonic effects on the recovery factor.

Simulation of thermodynamic systems in calcium-based chemical looping gasification of municipal solid waste for hydrogen-rich syngas production

This study explores calcium-based chemical looping gasification (CLG) as a method for managing municipal solid waste (MSW), with a focus on converting MSW into hydrogen-rich syngas. The innovative CS-MgO-ZrO2 calcium-based sorbent has been identified as optimal, facilitating fluidization crucial for operational stability and economic feasibility. Key discoveries include heightened H2 concentration and CO2 capture efficiency under specific operational parameters (4000 kg/h solid flow rate, 6000 kg/h steam flow rate), despite diminished H2 production at carbon conversion rates (≥0.80). Below 0.38 carbon conversion rates, a syngas injection ratio of 0.18, and oxygen flow rates >1200 kg/h induce spontaneous reactor heating, compromising efficiency and escalating costs. Furthermore, utilizing syngas in the regenerator ensures self-sufficiency and supplementary thermal energy, thereby reducing dependence on external energy sources. This research addresses critical deficiencies in waste-to-energy technologies, emphasizing potential strides in sustainable municipal waste management and energy generation.

Design and Performance Evaluation of a Specialized Bubbler System for Accurate and Repeatable Solid Oxide Electrolysis Cell (SOEC) Testing

Accurate assessment of Solid Oxide Electrolysis Cell (SOEC) performance demands standardized testing conditions, particularly in stable steam delivery. Fluctuations in steam concentration and flow rate can significantly impact measured open-circuit voltage (OCV) and polarization behavior. Although direct steam injection is straightforward, it is often hindered by instability resulting from intermittent liquid water flux, pressure fluctuations, and fractional distillation effects. Bubbler humidification systems have the potential to offer consistent steam, but tailored designs for SOEC testing are currently absent.This study introduces a specialized bubbler system designed to deliver stable steam to SOEC test stands accommodating both oxygen-conducting (O-SOEC) and proton-conducting (H-SOEC) cells. The bubbler components include a refill water reservoir, a level control module, heating elements, pressure relief valves, check valves, tubing, and fittings integrated with the test stand. The system humidifies the sweep gas, transporting steam to the cell test fixture situated within a high-temperature furnace.The design process involved meticulous considerations of materials compatibility, hydrogen safety, and overtemperature protection. All wetted components employ stainless steel, glass, or PTFE materials in their construction construction. Redundant thermocouples ensure safe process temperatures with automated overtemperature shut off. The refill reservoir and bubbler headspace operate near ambient pressure, facilitated by an exhaust line vent sized for minimal backpressure.In various executed O-SOEC tests, the bubbler maintained OCV stability within ±5 mV over several hundred hours for each cell operating at 750°C, eliminating spikes caused by steam fluctuations observed with direct injection methods. This facilitates precise electrochemical analysis and determination of area-specific resistance losses. Polarization curves align with expected behavior based on the Nernst equation. The system has demonstrated safe and stable functionality for over thousands of hours across various operating conditions.The bubbler design presents researchers with notable advantages over existing steam supply options for SOEC test stands, addressing performance, safety, and flexibility concerns. Online instrumentation enables closed-loop control of steam conditions, enhancing stability. Standardization of test equipment is crucial for quality results, and this work contributes progress toward reproducible protocols in the international SOEC community. The modular bubbler approach, integrated with safety features, also signifies safer methodology choices for lab-scale experimental research.

Oxygen blown steam gasification of different kinds of lignocellulosic biomass for the production of hydrogen-rich syngas

In this study, the gasification performance of different kinds of lignocellulosic biomass, including corn straw (CS), soybean straw (SS), cotton straw (CTS), rice straw (RS), wheat straw (WS), bamboo wood (BW), maple sawdust (MS), and pine sawdust (PS), was studied in a tube furnace reactor system under identical conditions (temperature = 800 °C, oxygen flow rate = 30 mL/min, steam flow rate = 5 ± 1 mL/min, and time = 55 min). SS showed good gasification characteristics and delivered the highest H2 yield of 28.96 mol/kg. By using the SS, additional optimization was carried out by considering different temperatures (650, 700, 750, 850, 950, and 1050 °C) and different oxygen flow rates (10, 20, 30, 40, and 50 mL/min). After optimization, the initial temperature and oxygen concentration were reduced to 750 °C and 10 mL/min, respectively. An H2 yield of 30.86 mol/kg was achieved with an increase of 6.56 %. Finally, catalytic steam gasification employing three potassium-based catalysts, KCl, KOH, and K2CO3, was tested using SS. KOH and K2CO3 performed distinctly better than KCl. The utilization of KOH as a catalyst resulted in the greatest H2 yield, measuring 39.22 mol/kg, which represents a notable improvement of 27.09 %.

Film investigation of swirl-vane separator based on Euler grid approximation and coupled film method of Eulerian wall film and volume of fraction method

The movement of multiple liquid droplets within steam flow constitutes a commonplace and noteworthy phenomenon across a spectrum of disciplines, including environmental science, chemical engineering, and energy studies. To simulate the dynamic behavior of these droplets, the methodology of Euler grid approximation, along with the Eulerian wall film (EWF) coupled with the volume-of-fluid (VOF) method, was successfully employed to simulate the steam-liquid separation and liquid film processes within the swirl-vane separator. The trajectory of droplets within the gas phase field was constructed using the Euler grid approximation methodology, while the flow of liquid film formed by droplet–wall collision was modeled based on the coupled EWF and VOF liquid film model. The investigation of two-phase flow and liquid film flow within the swirl-vane separator under high temperature and pressure conditions was conducted utilizing the proposed model, with subsequent analysis of the pertinent characteristics of droplets and liquid film. Specifically, the thickness and velocity of the liquid film significantly increased with the increase in droplet mass flow rate, with larger droplets more prone to concentrate and form stable flow of thick liquid film. The study results may hold significant implications for the design, operation, and optimization of separators.

Preparation and thermal properties of biomimetic polymer-based flexible ultra-thin flat heat pipe

Inspired by the structure of the human spine, a flexible ultra-thin flat heat pipe featuring a biomimetic human spine design has been devised. This flat heat pipe, equipped with a biomimetic human spine structure, is capable of undergoing repeated bending at large angles. An experimental study was conducted to investigate the primary influencing factors. The results revealed that the optimal liquid filling ratio for the flexible ultra-thin flat heat pipe is 0.3. The dip angle is positively correlated with the heat transfer performance of the flexible ultra-thin flat heat pipe, and the bending angle is negatively correlated with the heat transfer performance of the flexible ultra-thin flat heat pipe. The maximum thermal conductivity of the flexible ultra-thin flat heat pipe can reach 1457.68 W/(m·K). The flexible ultra-thin flat heat pipe with liquid filling rate of 0.3 and bending angle of 0 degree has the fastest start-up speed. A visualized experimental platform was further designed to observe the internal flow of the working fluid within the flexible ultra-thin heat pipe in various bending states. The visual experimental results demonstrate that bending initiates the premature condensation of steam within the flexible section, and the condensed working medium subsequently generates resistance to the flow of subsequent steam, leading to an inability for the latter to be smoothly transported to the condensing section, thereby creating a vicious cycle.

Thermo-hydro-mechanical coupling in oil shale: Investigating permeability and heat transfer under high-temperature steam injection

Steam convective heating emerges as a sustainable and effective method for extracting oil shale, where understanding the temperature-dependent evolution of its pyrolytic characteristics, microstructure, and permeability is vital for efficient resource extraction. Through a stress-sensitive micro-CT scanning and a high-temperature and pressure triaxial test apparatus, this research utilizes Balikun oil shale samples to investigate the changes in microstructure and gas production from 20 °C to 550 °C. The study integrates theoretical analysis and numerical simulations to uncover the fundamental connections between internal permeability and heat transfer mechanisms during steam injection. It reveals that oil shale undergoes two critical evolutionary phases: a stability phase below 350 °C, where volatile dispersion occurs, and a rapid increase phase above 350 °C, marked by significant microstructural changes from micro-fractures to extensive through-going fractures due to intense thermal decomposition. This decomposition leads to increased gas production and enhanced thermal fracturing. The threshold temperature is identified at 400 °C, above which the oil shale's mechanical strength and pore pressure increase, leading to decreased volumetric compression until stabilization. These findings demonstrate that higher temperatures enhance fracture connectivity and steam flow, optimizing the heating efficiency in oil shale extraction.

Exploring the role of hydrogen in decarbonizing energy-intensive industries: A techno-economic analysis of a solid oxide fuel cell cogeneration system

Industry is nowadays one of the most energy-demanding sectors representing a major contributor of global greenhouse gas emissions. The simultaneous need for electricity and high-temperature heat is what makes some industrial processes difficult to decarbonize via current commercially available technologies. As the demand for materials and goods is expected to grow in the upcoming years, it is crucial to define which strategies and technologies will serve as the cornerstone of sustainable development. This study addresses the imperative need for emission reduction of energy-intensive sectors by proposing a novel hydrogen-based cogeneration system in the framework of the paper and pulp industry, with the aim of providing general insights relevant to a broader spectrum of similar applications. The comparative analysis presented in this work focuses on three cogeneration options aimed at satisfying the paper mill energy needs: a conventional natural gas-fuelled gas turbine, a Solid Oxide Fuel Cell (SOFC) fed with grey hydrogen produced via steam methane reforming, and a SOFC operating using green hydrogen produced on-site. The latter involves an integrated multi-energy system with photovoltaic panels, electrolyzers, compressors, and storage tanks. Indeed, the SOFC potential of supplying electricity and high-temperature heat in the form of pressurized steam for industrial applications has not been well investigated yet and represents one of the main objectives of this work. Building on the real consumption profiles of a paper mill facility, techno-economic analyses are carried out for many system configurations, varying components size and layout to assess their performance with respect to CO2 emissions and two key economic parameters, the Levelized Cost of Hydrogen (LCOH) and the net present cost. An in-house-developed flexible simulation framework is presented and expanded for the purposes of this study, including a detailed model that accounts for design and off-design performance of a SOFC cogeneration unit. Results demonstrate that integrating a SOFC with a heat recovery steam generator result in a 75% reduction in the mass flow of generable pressurized steam in comparison to a gas turbine. Additionally, in the cost-optimal scenario, CO2 emissions are 25% lower than the conventional gas turbine-based configuration, achieving complete independence from the electricity grid and an LCOH of 5.81€/kg without considering revenues from electricity sold.

Effect of twisted tapes and surface extensions in enhancing the condensation heat transfer of high-temperature saturated steam in a circumferential rectangular channel

This article numerically investigates the impact of twisted tapes and extended surfaces (fins) on enhancing high-temperature steam flow in a circumferential rectangular channel, akin to the external jacket cavity of a tyre cure press. The passive enhancement techniques for improving the mold warm-up time of the tyre curing process have received limited attention in previous studies, which have primarily focused on enhancing heat transfer in configurations and working conditions typical of heat exchanger applications. The objective of this article is to enhance the condensation heat and mass transfer rate by geometrically modifying the internal flow path of the circumferential rectangular channel, resembling an external jacket cavity of a tyre cure press, using twisted tapes and extended surfaces. Four configurations are simulated: i) conventional circumferential rectangular channel, ii) channel with twisted tapes, iii) channel with surface extension, and iv) channel with both twisted tapes and surface extension. The heat transfer performance of all the modified channel configurations derived from the simulation results is assessed in comparison to the conventional channel. The channel, featuring a design that includes five twisted tapes with a twist ratio of 8 and 54 extended surfaces, records a substantial 36.85% rise in heat flux along with a notable 24% increment in the condensation mass flux. The simulation results are validated using an in-house experimental study. The tyre cure press in the experimental setup is modified to align with the design proposed by the simulation results, and a warm-up study is conducted. The warm-up time for the modified mold to attain the desired temperature is reduced by 33%, with no accompanying increase in steam consumption, compared to the warm-up time for the conventional mold. This significant reduction in mold warm-up time holds immense potential in enhancing the productivity rate, an ongoing requirement of the automobile industry.

Advancing hydrogen generation: Kinetic insights and process refinement for sorption-enhanced steam gasification of biomass utilizing waste carbide slag

Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (∼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.

CFD simulation of the influence of swirl intensity on entropy production for wet steam flow in supersonic dehydration

The energy loss within a supersonic separator is highly dependent on the cyclonic intensity. In this paper, an entropy production analysis model and a nonequilibrium condensation model are developed to study the liquefaction performance of the supersonic nozzle and the energy loss under different swirl intensities. With an increase in swirl intensity from 0 to 0.94, the nucleation starting point and Wilson point at the centerline move forward by 45.05 mm and 69.17 mm, respectively. The mass-average liquid fraction at the nozzle outlet increases by 28.81 %, but the flow rate decreases by 43.02 %, and the total entropy production experiences a 19.66 % increase. Indirect (or turbulent) dissipation dominates the total entropy production of wet steam flow resulting from the large gradient of velocity at the boundary layer, whereas phase change entropy production ranks second and mainly occurs in the nucleation region. Overall, the swirl intensity should be kept below 0.30 to achieve a balance between gas handling capacity, liquefaction performance, and energy loss for the supersonic nozzle.

Artificial intelligence vision technology application in sustainability evaluation of solar-driven distillation device

The process of transforming brackish water into freshwater utilizing solar thermal energy is referred to as solar-driven distillation device, or solar still. Such device without fossil fuel provides significant environmental and health benefits by reducing air pollutants and remedying brackish water. The yield of purified water from conventional solar stills remains insufficient, prompting the necessity for research to enhance it by understanding the coupling effect between steam flow, heat transfer, and mass transfer. As such, computer-aided brackish water treatment comparison of the hemispherical solar still and other multi-slope solar stills is conducted in this paper, and an automatic steam&heat flow detection algorithm is developed to solve the problem of difficult data acquisition for gas-liquid transport processes. Firstly, double slope, four slope, and hemispherical solar stills are exposed to the sun in outdoor experiments, therefore the solar thermal performance of each still is analyzed through pairwise comparisons. Secondly, a large amount of experimental image data is input into neural network for training, and by continuously adjusting network parameters, the network can accurately recognize different types of images. Finally, the image to be recognized is input into the trained neural network, which outputs the category labels of the image to achieve automatic image recognition. Based on the data above, the best structure of solar-driven device is hemispherical structure, due to that the hemispherical solar still possesses the best performance in terms of distilled water yield, energy efficiency, exergy efficiency and energy payback.

Comparison of diffusion coatings resistance on ferritic and austenitic-stainless steels at 650 °C in steam oxidation

Iron-aluminide coatings were deposited on T24, P92 and Incoloy 800HT (IN-800HT) by pack-cementation and by a water-based slurry. According to the differences in heat treatments between the two processes, Al-rich phases, i.e. Fe4Al13 and Fe2Al5 were obtained by pack cementation and only B2-(Fe, Ni)Al by slurry. Vertical or horizontal cracks were present on certain coatings, the former being due to the coefficient of thermal expansion (CTE) mismatch with the substrate while the latter were related to the brittleness of the Al-rich phases. The oxidation behaviour of uncoated and coated substrates was studied at 650 °C up to 1000 h under a low steam flow rate (1.07 × 10−5 m/s). The aluminide coatings were very protective on the low Cr substrates (i.e. T24 and P92) because of the formation of a very thin oxide scale compared to the non-protective thick layers of Fe3O4 and Fe2O3 that grew on both uncoated substrates. In contrast, none of the coatings significantly improved the oxidation resistance of the IN-800HT steel despite the growth of a thin oxide layer made of (Fe, Cr)2O3 and (Fe, Cr)3O4 at 650 °C.

Cause Analysis and Improvement Measures for Superheated Platen Tubes Failure of a 580 t/h CFB Boiler

Superheaters are crucial components of boilers operating under high temperatures and pressures. Understanding potential damages, especially in components like superheaters, is essential for enhancing boiler, turbine, and overall power plant productivity. This paper highlights a study for the failure investigation of platen superheater tube in Unit 2 of a 2x150 MW coal-fired power plant in South Sumatra. Various tests including chemical composition, hardness, tensile, metallography, SEM fracture surface examination, and XRD compound analysis were conducted to assess the failure of the platen superheater tube. The investigation revealed that the failure of platen superheater tube was initiated by the plugging of the tube elbow due to deposits and ashes adhering to the tube's interior. This obstruction prevented saturated steam flow inside the tube, leading to overheating and a subsequent drop in mechanical strength. Overheating was confirmed by the presence of spheroid particles in the ferrite matrix. Prolonged overheating resulted in the formation of microvoids, leading to creep failure and crack formation in the tube. Following improvements made during Unit 2 maintenance outage, which involved adding refractory material inside the furnace on the platen superheater panel, positive results were observed. The platen superheater tubes, which previously exceeded temperature limits, now operate within normal range temperatures. This improvement also reduced spray water consumption and significantly increased boiler efficiency from 83.19% to 83.54%.

AN EXPERIMENTAL STUDY ON THE USE OF SEDIMENTATION COMPOSITIONS DURING STEAM INJECTION

At present time, many oil fields, especially in historically developed areas of The experience of developing deposits of high-viscosity oils (HVO) and natural bitumen has shown that thermal methods are the most promising technologies. Of the entire arsenal of thermal methods, areal steam injection and cyclic-steam stimulation have become the most widespread.When choosing an effective thermal impact technology, it is necessary to take into account the peculiarities of the geological and physical parameters of deposits and the factors involved in oil recovery. An effective technology should be based on the use of the main most important factors that increase oil recovery.One example of areal steam injection is the underground-surface method of developing the Yarega area of the Yaregskoef ield. With this technology, steam is pumped from the surface through vertical wells. Oil production is carried out in the underground galleries of the oil sheds.Twenty years of practice and geophysical studies of steam injection wells have revealed a number of factors that prevent uniform heating of the reservoir over the entire thickness and efficient use of coolant energy. It turned out that the injected steam is mainly concentrated in the bed zone of the formation. In this case, the formation does not warm up evenly in thickness. The heterogeneity of the reservoir (tectonic disturbances, cracks every 20-25 m) does not allow the creation of steam pressure up to 1,6 MPa along the contour of the developed areas in order to involve the inclined block. At design pressures, steam breaks into mine workings and gently descending production wells are observed.The experimental studies described in this work are aimed at finding alignment of the intake profile of steam injection wells and redistribution of coolant in a remote reservoir zone. The results of the application of sedimentation compositions in bulk reservoir models under various thermobaric conditions of steam injection are presented. As a result of injection of solutions of iron sulfate, sodium carbonate and calcium chloride, insoluble sediments were formed in the rock, which led to a decrease in permeability during water vapor filtration. The experimental study was performed on a bulk reservoir model using natural core grinding, as well as drilled and extracted core samples from wells of the Yaregskoe field. The use of sedimentation compositions in steam injection wells in the future may contribute to the involvement of rock sections in the development by redistributing the steam flow, which in turn will increase the oil recovery coefficient and reduce the steam-oil ratio.

Pre-pilot scale study of hydrogen production from biomass syngas via water-gas shift in Pd–Ag catalytic membrane reactor and dedicated hydrogen permeation unit

The water-gas shift reaction (WGS) was evaluated in two Pd–Ag membrane reactors operating in parallel and capable of processing 0.25 Nm3·h−1 of syngas. Various configurations, syngas compositions, and steam flow rates were explored within the temperature range of 300–350 °C and pressure range of 4–8bar. The performances were evaluated in a coupled configuration, consisting of a permeator and a membrane reactor operating in series, and single configuration of membrane reactor. Two syngas mixtures were fed and treated under different combinations of temperature, pressure, and steam/CO ratio. The syngas composition used was, in one case that typically produced by updraft gasifiers operated with air and having a content of H2 19.1 vol% and, in the second case, having content of 36.8 vol%, typically achievable by oxy-steam gasification. Carbon monoxide conversion, hydrogen permeation, and hydrogen permeability of membranes were determined. The use of these membranes effectively enhances the WGS reaction, overcoming the performances of a Gibbs reactor, and produces streams of ultrapure hydrogen. Competitive strong adsorption of CO was suggested from the permeability analysis and comparison with existing literature.

Design of SWRO Desalination Plant for Nuclear Research Center

Libya has an infinite water resource available inthe coastal towns and cities being located on Mediterranean Sea with 1950km coast. Therefore, the need for desalinatedwater for Nuclear Research Center NRC located in Tajurais currently about 1200 m3/day. To cover the center presentand future water needs for research and developmentactivities, two thermal sea water desalination plants have been assembled in the site. One of the plants uses MultiStage Flash technology and the other one uses Multi EffectDesalination technology with capacity of 1200m/day eachone. Detailed design for 1200m3/day seawater reverseosmosis SWRO unit is carried out using ROSA S oftware to make the technical comparison with other MSF and MEDunits. The unit labeled an S W30XLE-440i by the results ofthe Software is selected since it required the lower feedpressure of 55.5bar and highest salt recovery of 45% with total dissolved solid of 190ppm. From the technical point ofview, the study showed that SWRO required lower seawater inlet flow rate than MSF and MED. The unitsefficiency are 43%, 10.5% and 25% for SWRO, MSF, andMED, respectively. Further the Product quality TDS 190ppm for RO unit is suitable for drinking water, whilethose of MSF and MED 50ppm. Energy consumption asheating steam is not required for the S WRO unit; however,a steam flow rate 7.3m 3/hr is required by MSF and MEDunits. These make SWRO unit friendlier to the environment and most proper technically under these situations.

Prediction of Water Production Rate Using Fuzzy Logic Approach

Abstract—this paper describes a fuzzy expert system approach for prediction of water production rate in a desalination plant. The goal of the study is to predict water production rate based on several inlet variables determined by steam flow, steam pressure, seawater temperature, and seawater flow. The data used were collected from plant history records of the operation department log sheets. These data were analyzed and a model was constructed using fuzzy expert system. In the proposed model, both input and output variables are parameterized and classified into several fuzzy sets. A set of fuzzy rules are constructed based on the knowledge extracted from the data collected. Once the rules are evaluated, the variables are defuzzified and converted into corresponding output variable (water production rate). The results showed that inlet variables of the plant could predict water production rate with 95% prediction accuracy.

Impact of deodorisation time and temperature on the removal of different MOAH structures: a lab-scale study on spiked coconut oil

Vegetable fats and oils are prone to contamination by mineral oil hydrocarbons due to the lipophilic and ubiquitous character of the latter. As the aromatic fraction of these hydrocarbons, MOAH, is associated with carcinogenicity, mutagenicity, and detrimental effects on foetal development, finding strategies to limit or reduce their contamination is highly relevant. Deodorisation (i.e. a refining step) has shown the ability to remove MOAH < C25 in vegetable fats and oils, but there is little information about the structures removed. Therefore, the present study investigated the impact of deodorisation conditions on the removal of different structures of MOAH in spiked coconut oil. An inscribed central composite design was built with time and temperature as variables (0.5-4h, 150-240 °C), while pressure (3 mbar) and steam flow (1 g water/g oil per hour) were kept constant. The analysis of MOAH in the oil was performed using a fully automated liquid chromatography coupled with two parallel comprehensive two-dimensional gas chromatography systems with flame ionisation and time-of-flight mass spectrometric detection. Response surfaces plotting the MOAH loss according to time and temperature were built for different MOAH fractions. The latter were defined based on the number of aromatic rings (>3 or ≤3) and the number of carbon atoms present (C16-C20, C20-C24, C24-C35, C35-C40). It was found that at 200 °C, compounds < C24, including weakly alkylated triaromatics, could be reduced to below the limit of quantification, while at 230 °C, it was possible to remove >60% of the C24-C35 fraction, including pentaromatics of low alkylation.