Superheated Water Vapor Research Articles

Production of Ferromagnetic Adsorbents from Solid Products of Biowaste Carbonization in a Fluidized Bed in a Medium of Superheated Water Vapor

Production of Ferromagnetic Adsorbents from Solid Products of Biowaste Carbonization in a Fluidized Bed in a Medium of Superheated Water Vapor

Investigation on the effect of superheated water vapor on gas production from pyrolysis of long-flame coal

A self-developed superheated water vapor pyrolysis system was used to conduct superheated water vapor pyrolysis experiments on Tashan and Madaotou long-flame coals at 350–534 °C. The gas phase products were analyzed by gas chromatography. The yield and composition of gas phase pyrolysis products from two different long-flame coals were determined, and the role of superheated water vapor in the pyrolysis process was elucidated. The optimal temperature of the long-flame coal injection superheated water vapor mining technology was obtained through heat value analysis. The results showed that when the temperature of the superheated water vapor exceeded 400 °C, the yield and combustible components of the gas phase products rapidly increased. As such, the release rate reached 10–15 times that observed below 400 °C, and the components of the combustible gases, such as hydrocarbon gas and hydrogen, exceeded 80%. Superheated water vapor not only is an excellent heat and mass transfer medium, but also provides a reactant for the re-formation reaction of hydrocarbon gas. The pyrolysis of long-flame coal under superheated water vapor at 500 °C yielded the best economic benefits. The low calorific value of gas phase products produced via pyrolysis per ton of coal per unit time could reach 715 MJ/(t·h).

Carbonization of excess sewage sludge using superheated water vapor to produce fuel

Excess sewage from activated sludge treatment of municipal wastewater is considered one of the most severe solid waste problems. The excess sewage sludge with 64% moisture content was converted to valuable material throughout the superheated water vapor carbonization process. The superheated water vapor carbonized the excess sewage sludge using a bench-scale Rotary Kiln setup to make fuel at 200°C, 250°C, 300°C, 350°C and 400°C. The effect of carbonization with superheated water vapor on the yield and heating value of fuel was studied. In 1 h treatment, organic waste lost about 70% of its original weight due to volatile release during carbonization. The yield of carbonization decreased when the temperature of carbonization increased. A carbon, hydrogen, nitrogen, and sulfur (CHNS) analyzer was used to measure the elemental composition of the carbonized product. The heating value (LHV) of the fuel carbonized at 250°C was 15.0 MJ/kg, determined by a bomb calorimeter. Thus, this study has shown that instead of the landfill, excess sewage sludge can be utilized using superheated water vapor for conversion to fuel.

Velocity overshoot within the accelerated subsonic boundary layer over the heated wall

The paper presents results on the numerical investigation of the accelerated compressible flow near the hot surface with constant heat flux. Such conditions may generate a phenomenon of the overshoot, when the streamwise velocity within the boundary layer is higher than the velocity of the main flow. We simulated properties of helium-xenon mixture and superheated water vapor. Numerical model consist of the system of Prandtl equations, which describe dynamic and thermal processes in the boundary layer, and k-ω-γ turbulence model that allows simulate reasonably as turbulence as laminar-turbulent transition. Finite difference methods were applied for solving of differential equations. The numerical model was able to block artificial the term of viscous dissipation in the energy equation and set a constant temperature at the outer border of the boundary layer in order to evaluate the effect of compressibility on the overshoot phenomenon and other flow characteristics. It is shown that the unambiguous relationship between skin friction coefficient and the overshoot magnitude is violated for Mach number from 0.4 to 1.0. Maximal values are disappeared at representation of velocity through Mach number.

Electrothermal Devices for Gas-Thermal Processing of Structural Metals and Alloys

The provided designs of cylindrical electric resistance furnaces were designed to strengthen the heat treatment of a wide range of metal products with various applications. Special-purpose electric furnaces allow carrying out strengthening heat treatment of metal and alloy surfaces in reaction process medium comprising air, superheated water vapour, a mixture of inert and oxidising gases with the formation of thermal oxide coatings with increased indicators of both wear and corrosion resistance.

Снижение энергетических затрат при управлении установкой ректификации нефти

Introduction. Methods for assessing the energy efficiency of small oil refineries are not sufficiently developed currently. Aim is an optimizing the energy costs of oil separation. Materials and methods. An algorithm for calculating the sectional model of the atmospheric unit of a lowpower oil distillation unit is presented. The resulting model is supplemented by the calculation of an air-cooling apparatus and a shell-and-tube heat exchanger. The factors affecting energy costs were selected: the consumption of superheated water vapor in the atmospheric and stripping columns, reflux ratio, and the consumption of raw materials. To derive the dependence of the selected criterion on the listed factors, the method of orthogonal central compositional planning of the experiment was applied. A planning matrix for a four-factor experiment using the sectional model is compiled. The results of the experiment have been obtained in the MATLAB software package. An estimation of the insignificance of the coefficients in the obtained second-order regression equation is carried out; insignificant coefficients are excluded from the model. The adequacy of the model was verified using the Fisher criterion. The regression equation represented in the physical quantities of the factors is the objective function. Results. The surface of the output parameter is constructed depending on control factors (reflux number and flow rate of superheated water vapor into the atmospheric column) with a constant flow of raw materials and a constant flow of superheated steam into the stripping column. It is shown that the selected factors affect not only energy costs, but also the quality indicators of petroleum products. Mathematical models are given for determining the quality indicators of oil products (temperatures of the beginning and end of boiling) at an oil refinery, which are used as limitations. The application of the obtained dependence is proposed for optimizing energy costs at an oil distillation unit with a changing consumption of raw materials. Conclusion. The obtained optimal values of the factors can be used as tasks for the regulators on the current installation.

Studying the diesel flame structure in superheated water vapor jets by using IR thermography

The use of water and water vapor in fuel combustion positively affects both environment parameters and the device stability. This is effective in the disposal of low-grade liquid hydrocarbons. The work is devoted to the experimental study of thermal characteristics of flame (effective emissivity and temperature) during the combustion of liquid fuel sprayed by a superheated steam jet, which is to supplement information on the steam effect on key parameters of fuel combustion. The measurements were carried out in a new burner at different operating parameters (fuel and steam mass flow rates and steam temperatures). During the first step of the research, high-quality liquid hydrocarbon (diesel fuel) is chosen, which is usually used in burners. In the study, we used a JADE J530SB FLIR thermal imaging camera and a type B platinum-rhodium-platinum-rhodium thermocouple. Instantaneous and average temperature fields were obtained; the peak flame temperature attained 1440 °C. It is found that the effective emissivity value (ε = 0.3 ÷ 0.4) depends on the steam and fuel flow rate that is connected with the completeness of fuel combustion and soot concentration in the flame. An increase in the steam flow rate decreases the flame temperature by more than 200 °C, which prevents the formation of thermal nitrogen oxides. The thermal imaging measurements well agree with thermocouple data (within 9%).

Carbon Sorbent Based on Special Fine Coke for the Extraction of Gold

The production of carbon sorbents based on special fine coke using a combination of steam and gas activation (by gas after the carbonization of Shubarkol coal with carbon dioxide and superheated water vapor) and chemical activation (by sodium hydroxide) was studied. Their textural and sorption properties were characterized. The necessity of separating the carbon and mineral parts of the special fine coke by elutriation in water was shown. The high adsorption capacity of the samples for gold ions was established (the recovery was 99.4–99.9%). The method for the production of a sorbent based on special fine coke in order to extract gold from cyanide solutions and the optimal conditions for its adsorption were recommended.

Numerical Investigation of a Steam Nozzle with Focus on Non-Equilibrium Condensation and Unsteady Flow Behavior

Present work analyses the condensation of superheated water vapor in supersonic Barschdorff nozzle. The influence of pneumatic mounts in 3D laval nozzle is analyzed using steady and unsteady two phase non-equilibrium condensation steam flow model in Ansys CFX16. Mesh independency studies in 2D model showed that at a lower inlet total temperature and very fine mesh (e.g. 100.2°C and 77k mesh elements) there is problem with the convergence using steady simulation. This is possibly due to the ability of very fine mesh to capture the small flow unsteadiness. The variation in location of Wilson’s point, Wilson’s pressure and maximum sub-cooling rate at the centerline of the nozzle is below 1.5%. The 2D CFD nucleation rate is 50% stronger and droplet diameter is 18% higher compared to the 3D CFD results. The deviation in nucleation rate and droplet diameter at nozzle outlet is the result of dissipation due to wing structure in the 3D model. Nucleation zone predicted by Ansys CFX16 is far upstream the experimental one. Different correction factors in modified nucleation model were used to fit the computed pressure distribution with the experimental one. The correction factor is dependent on boundary conditions and nozzle profile. It is thus concluded that the significance of such correction factor is not unique.

Estimation of strength degradation for engineering plastic (Under elevated temperature and humidity stress test)

A large quantity of engineering plastics are used in electric industrial products. It is necessary to estimate the life of the product made of engineering plastics because of its shorter life and lower strength than some of ceramics or metals. New test device was developed for accelerated stress test. It can make the unsaturated environment above 100 oC under atmospheric pressure using superheated water vapor. Then it becomes possible to set wide range condition of temperature and humidity. Polybutylene terephthalate (PBT) is one of the hydrolyzed engineering plastics. Test pieces of PBT were submitted to accelerated stress test under some conditions of elevated temperature and humidity. Then they were provided to three point bending test. The time required for strength degradation has a good relation with water vapor pressure at each temperature. Then it became clear that the time required for strength degradation on each water vapor pressure was accelerated with temperature using the Arrhenius type equation.

Temperature determination of superheated water vapor by rotational-vibrational Raman spectroscopy.

We present a novel non-invasive laser-based tool for tracer-free spatially resolved temperature measurement in superheated water vapor at atmospheric pressure. The technique exploits the temperature sensitivity of the rotational-vibrational Raman spectrum of the v1 stretching vibration. This Letter demonstrates the Raman sensor, its application to a steam gasification reactor, and four methods to analyze the Raman spectra in order to obtain the temperature: an equal intensity point approach, a pseudo-isosbestic point approach, and two approaches based on the reconstruction of the Raman band by Gaussian/Lorentzian profiles. The evaluated water vapor temperatures inside a reactor for plasma-assisted gasification are compared to data acquired by supercontinuum absorption spectroscopy.

Numerical analysis of shell-side thermo-hydraulic performances of submerged combustion vaporizer

Submerged combustion vaporizer belongs to one of the frequently-used and high efficient heat exchanger in the LNG industry chain. In this paper, in order to have a more profound understanding of shell-side thermo-hydraulic performances of submerged combustion vaporizer, an integrated thermal model is built to investigate the direct-contact flue gas and water mixture sweeping across the stagger tube bundle, with the condensation process of superheated water vapor presence. The accuracy of numerical model and method is validated by the experimental test data. On this basis, the unique flow and heat transfer mechanism is firstly analyzed, then variations of the gas hold-up, heat transfer and pressure drop performances with the common operational parameters are systematically studied. Significant results demonstrate that the efficient direct-contact condensation heat transfer process occurs between highly turbulent gas-liquid two-phase flow and tube bundle wall. The distinct and interesting circulating water forms due to the existence of weir, which helps to reduce the fluid boundary layer and strengthens the heat transfer. The water bath efficiently absorbs the sensible heat and latent heat carried by flue gas so that the outlet flue gas temperature almost equals to the water bath temperature. When the gas hold-up is within the scope of 25–45%, the shell-side convective heat transfer ability is obviously enhanced. Finally, in view of the numerical results, a new dimensionless pressure drop correlation and Han model are suggested for the optimum design of submerged combustion vaporizer.

Combination of Functional Nanoengineering and Nanosecond Laser Texturing for Design of Superhydrophobic Aluminum Alloy with Exceptional Mechanical and Chemical Properties.

Industrial application of metallic materials is hindered by several shortcomings, such as proneness to corrosion, erosion under abrasive loads, damage due to poor cold resistance, or weak resistance to thermal shock stresses, etc. In this study, using the aluminum-magnesium alloy as an example of widely spread metallic materials, we show that a combination of functional nanoengineering and nanosecond laser texturing with the appropriate treatment regimes can be successfully used to transform a metal into a superhydrophobic material with exceptional mechanical and chemical properties. It is demonstrated that laser chemical processing of the surface may be simultaneously used to impart multimodal roughness and to modify the composition and physicochemical properties of a thick surface layer of the substrate itself. Such integration of topographical and physicochemical modification leads to specific surface nanostructures such as nanocavities filled with hydrophobic agent and hard oxynitride nanoinclusions. The combination of superhydrophobic state, nano- and micro features of the hierarchical surface, and the appropriate composition of the surface textured layer allowed us to provide the surface with the outstanding level of resistance of superhydrophobic coatings to external chemical and mechanical impacts. In particular, experimental data presented in this study indicate high resistance of the fabricated coatings to pitting corrosion, superheated water vapor, sand abrasive wear, and rapid temperature cycling from liquid nitrogen to room temperatures, without notable degradation of superhydrophobic performance.

Effect of gas properties on accelerated laminar boundary layer over a heated wall

The paper reports on numerical investigation of an accelerated laminar boundary layer over a heated wall at Prandtl numbers from 0.23 to 2.39. Properties of three gases were simulated: air, helium-xenon mixture and superheated water vapor. The finite difference method was applied to solve a system of laminar boundary layer equations with variable gas properties. It has been shown that the influence of Prandtl number, viscosity, heat conductivity and heat capacity on the flow at studied conditions is secondary relative to gas density, which is the determinant factor for the overshoot magnitude and other flow parameters. Nevertheless, at insignificant differences in density distributions the overall decrease of Prandtl number and decrease of viscosity and heat capacity and increase of heat conductivity separately lead to an increase of maximal velocity within the boundary layer.

7-15.過熱水蒸気による自動車廃オイルからの燃料ガス生成((4)廃棄物有効利用1,Session 7 環境対策・リサイクル)

7-15.過熱水蒸気による自動車廃オイルからの燃料ガス生成((4)廃棄物有効利用1,Session 7 環境対策・リサイクル)

Glycerol steam reforming for hydrogen and synthesis gas production

In this experimental study, glycerol conversion to hydrogen and synthesis gas was carried out by utilizing thermal plasma technology. An entrained-flow reactor equipped with a direct current arc discharge plasma torch, which was used to heat plasma-forming gas via Joule heating effect, and superheated water vapor, which was used to form the plasma, as a main reaction agent and a source of active radicals generation during steam reforming process of glycerol, set up a core of the glycerol conversion system. Glycerol, which is a by-product of biodiesel production during transesterification process, is considered to be a potential feedstock for renewable energy, biofuels, and high value-added chemicals production, such as methanol, hydrogen, etc. The reforming of glycerol was performed at various experimental conditions by changing the flow rate of water vapor and glycerol as well as the plasma torch power. The obtained results showed that the main reaction products were hydrogen and carbon monoxide with total concentration up to 75%. Moreover, the process was quantified in terms of cold gas efficiency, energy efficiency, carbon conversion, and specific energy requirement. Generally, the performed study indicates that hydrogen and synthesis gas could be effectively produced from glycerol by employing thermal plasma technology.

COAL MINI CHP PLANTS ON THE BASIS OF A GAS GENERATOR AND ELECTROCHEMICAL GENERATOR

Synthesis gas for electrochemical generator was produced in gas generator with automatic steam gasification of coal Borodino deposits. The paper compiles the thermal balances battery of solid oxide fuel cells (SOFC) and boiler, intended for production of superheated water vapor for a gas generator and heating the cathode air. On the base of these balances, the proportion of hydrogen, oxidized anode SOFC; electrical efficiency; the temperature in the anode; losses with flue gases and to the surroundings through the thermal insulation; fuel cell EMF were calculated. Moreover, it was determined unit cost of coal for the production of electrical and heat energy.

Environmental technology: Fluidised-bed steam dryers — latest developments and practical experience

Fluidised-bed steam dryers have been in use for industrial-scale drying of pressed beet pulp for more than 20 years. This highly energy-efficient process can be considered to be state of the art in the industry. Scientific laboratory and pilot-plant testing have provided the basis for a detailed description of the principles of fluidisation and drying in superheated water vapour. Advances in production data acquisition, in particular regarding the options for the real-time presentation and evaluation of high-resolution operating data (Industry 4.0), have opened up new potentials for optimisation of the drying process in fluidised-bed steam dryers. By analysing and interpreting sequences of events, or simultaneous events, it is now possible to analyse process behaviour in great depth. This allows malfunctions to be avoided by improved design or, assisted by suitable measuring and control systems, to be detected at an early stage. Failures can then be prevented altogether by initiating automated countermeasures. On the basis of more recent insights gained from the analysis of faults and disruptions using modern operating data acquisition, BMA’s fluidised-bed steam dryer (WVT) has been subjected to fundamental technological and technical improvements, so it now meets today’s demands for efficiency and reliability. Modifications include the product inlet, the distribution plate and several other parts, in addition to the known and patented PPS (Plug Protection System; EP 2457649 B1), and the patented rotary weir (EP 2146167 B1).

Decomposition of Bamboo Powder for Eco-Friendly Material Development by Using Superheated Steams

The purpose of this study is to investigate an alternative method to decompose bamboo for the development of new eco-friendly materials. The effect of superheated steam treatment on the chemistry of decomposed bamboo biomass was investigated; the composition of the decomposed biomass was quantitatively determined, and its molecular structures were also evaluated by IR spectroscopy. The ability of the decomposed bamboo biomass to be molded without the use of binders was also investigated, and the mechanical properties of the molded samples were investigated by a dynamic hardness test. The raw material, consisting of bamboo powder and pure water were put into the reactor and sealed tightly. To decompose the raw material, the temperature of reactor was elevated by the ring furnace to a specified level and maintained for 10 min. After the decomposition, three types of determinations, holocellulose, α-cellulose, and lignin determination were performed for quantitative evaluation. The IR spectrum of decomposed bamboo powder was also measured by using FT-IR to evaluate the molecular structure. For investigate the ability of the decomposed bamboo powder to be molded without the use of a binder, the compression molding technique was employed. The young’s modulus of molded products was measured by using dynamic hardness tester. Quantitatively determination results revealed that, when the superheated vapor treatment was conducted in the temperature range from 200 to 220°C, a solid residue containing mostly α-cellulose and lignin was obtained. IR spectrum evaluation revealed that the cellulose was decomposed by the superheated steam at 200 °C and above. The young’s modulus of compression molding products also revealed that the lignin contained in the decomposed bamboo powder improved the thermosetting ability after the superheated water vapor treatment. These results suggested that the superheated steam treatment was effective to obtain the decomposed bamboo for the development of new eco-friendly materials.

1-2-1 TiO_2-ZrO_2系触媒を用いた水蒸気雰囲気下での重質油の軽質燃料化(Session 1-2 重質油、コプロセッシング)

1-2-1 TiO_2-ZrO_2系触媒を用いた水蒸気雰囲気下での重質油の軽質燃料化(Session 1-2 重質油、コプロセッシング)