High Pressure Superheated Steam Research Articles

Effect of temperature on the preferential intergranular oxidation susceptibility of thermally-treated Alloy 600

Thermally-treated Alloy 600 coupons were tested in pressurized water reactor simulated primary water at 320 °C and in high-pressure superheated steam at 400 °C to study the effect of a “semi-continuous” network of intergranular carbides on the stress corrosion cracking “precursors events”: preferential intergranular oxidation (PIO) and diffusion-induced grain boundary migration (DIGM). The intergranular carbides were partially consumed due to the environmental exposure, whereby the Cr released from the carbides contributed to the formation of the external oxide layer that limited both PIO and DIGM. The results were compared with previous studies in which similar coupons were exposed to H2-steam.

A novel mathematical modelling platform for evaluation of a novel biorefinery design with Green hydrogen recovery to produce renewable aviation fuel

A novel integrated biorefinery system consists of (1) pyrolysis of biomass into gas, bio-oil and char; (2) bio-oil hydrodeoxygenation and hydrocracking (hydroprocessing) producing renewable jet fuel and small chain alkanes; (3) alkane steam reforming and pressure swing adsorption (PSA) producing green hydrogen and carbon monoxide; (4) mixed ionic electronic conducting membrane (MIEC) splitting high pressure superheated steam (HPSS) into green hydrogen and oxygen; and (5) combined heat and power generation (CHP) using pyrolysis gas and carbon monoxide from PSA as fuel with oxygen from MIEC, to fulfil the demand for HPSS and electricity. Comprehensive mathematical models are shown for the design simulation of the integrated system: (1) kinetic model of biomass pyrolysis at temperature 300−500 °C, (2) stoichiometric chemical reaction model of hydroprocessing, (3) renewable aviation fuel property correlations from its chemical compositions for the ASTM D7566 standard, (4) mass and energy balance analyses of the integrated biorefinery system. Economic value and overall avoided environmental and social impacts have been analysed for sustainability. The ratios of mass and energy flows between biomass, bio-oil, renewable jet fuel, CHP-fuel, char and hydrogen are 1.33:1:0.45:0.3:0.16:0.05 and 1:0.82:0.7:0.41:0.14:0.22, respectively. For 10tph bio-oil processing, the capital cost of the plant is $13.7 million, the return on investment is 19% and the cost of production of renewable jet fuel is $0.07/kg, which is lower than its market price, $0.27/kg. This production can curb 108 kt CO2 equivalent and 1.44 PJ fossil energy per annum. To enable the biorefinery simulation, user-friendly open-source TESARREC™ https://tesarrec.web.app/sustainability/bio-jet-fuel has been developed.

Process and Energy Optimisation - A Case Study of UB FGR fan at Captive Power Plant of NRL

The old saying “Excellence is the gradual result of always striving to do better……. The noblest search is the search for excellence.” – An integrated approach to achieve continuous improvement and reach towards excellence in Utility Boiler Operation. This paper highlights the case study carried out regarding the successful trial run of the Flue Gas Recirculation of the Utility Boiler of Co-generation plant of the Numaligarh Refinery Limited, Golaghat, Assam. This fan could not be put into service since commissioning of the boiler. Once it is successfully taken into service, many positive outcomes are noticed and resulted in the process and energy optimization in the operation of the utility boiler. In Numaligarh Refinery Limited (NRL), Co-generation plant (CGP), Utility Boiler (UB) is used to produce High pressure super-heated steam. One of the accessories named Flue Gas Recirculation (FGR) could not be put into service due to certain problems. FGR is a combustion modification process. As the name implies, a portion of the combustion products exiting the boiler are recirculated and introduced into the primary combustion zone. In UB, there are two nos. of FGR fans. But they could not put into service for a long time since commissioning. After a series of studies and experiments, the problems or factors were identified viz. Selection of correct UB load at which the fan should be started, dampers adjustment, burner flame stability, etc. After identification and trouble shooting of these problems, the FGR fans could be run successfully and put into continuous service. Following advantages were achieved in UB after the service of the FGR fans  Increases steaming rate of the U  Saves Energy (Fuel optimization)  Reduced harmful NOx gas Emissions  Increased in flue gas back end temperature  Lowers Greenhouse gas CO2 emission as the amount of fossil fuel is reduced Thus the above case study helped one of the important UB accessories to successfully put into service leading to various benefits, flexibility and process optimization in the operation of the UB.

Thermoeconomic analysis of an integrated multi-effect desalination thermal vapor compression (MED-TVC) system with a trigeneration system using triple-pressure HRSG

In this research, thermoeconomic analysis of a multi-effect desalination thermal vapor compression (MED-TVC) system integrated with a trigeneration system with a gas turbine prime mover is carried out. The integrated system comprises of a compressor, a combustion chamber, a gas turbine, a triple-pressure (low, medium and high pressures) heat recovery steam generator (HRSG) system, an absorption chiller cycle (ACC), and a multi-effect desalination (MED) system. Low pressure steam produced in the HRSG is used to drive absorption chiller cycle, medium pressure is used in desalination system and high pressure superheated steam is used for heating purposes. For thermodynamic and thermoeconomic analysis of the proposed integrated system, Engineering Equation Solver (EES) is used by employing mass, energy, exergy, and cost balance equations for each component of system. The results of the modeling showed that with the new design, the exergy efficiency in the base design will increase to 57.5%. In addition, thermoeconomic analysis revealed that the net power, heating, fresh water and cooling have the highest production cost, respectively.

Oxidation of low-alloy steel in high temperature steam and supercritical water

The oxidation behaviour of a low-alloy steel T22 was investigated by exposure to ordinary pressure steam (0.1 MPa), high-pressure superheated steam (8 MPa), and supercritical water (SCW) (25 MPa) at 600 °C for 1000 h. The results show the exposure pressure has a significant influence on weight gains and oxide scale morphologies. All the samples approximately obey near-parabolic oxidation kinetics. Some pores are found on the samples exposed to steam while severe cracks are formed in SCW. Further, the influence of steam pressure on the oxidation process is discussed in detail.

Опыт организации водно-химического режима с применением пленкообразующих аминов на тепловых электрических станциях с парогазовыми установками

The list of thermal power stations equipped with combined-cycle plants (CCPs) at which chelamine is used as a correcting reagent is presented. The advantages of this reagent and advisability of using it are pointed out. The main drawbacks of cycle chemistries based on film-forming amines are formulated, namely, low pH values in the low-pressure boiler water with high pH values in superheated low-pressure steam and high concentrations of ammonia in superheated steam. The effect the concentration of a complex reagent has on the water and steam quality parameters during the operation of a 110 MW combined-cycle unit in its nominal mode is outlined. Measures taken for optimally conducting the cycle chemistry with metering complex reagents as applied to a CCP are considered. The results from regime-adjustment tests of the cycle chemistry of a heat recovery steam generator with metering a complex reagent are described. It has been revealed that in case of using Type 906 H chelamine, the specific electrical conductivity of the H-cation sample of high-pressure superheated steam exceeds the values prescribed by the temporary regulations, and that the pH of the low-pressure circuit's boiler water is at the lower limit of the range prescribed by these regulations. A transition for using Type BRW 150H reagent, which is characterized by a lower distribution ratio between boiling water and saturated steam, has been done. The results obtained from the regime-adjustment tests in the cases of using chelamine of types 906H and BRW 150H were subjected to a comparative analysis. It has been revealed that the replacement of the chelamine type (with the reagent concentration remaining the same) resulted in a higher concentration of sodium, higher conductivity of the H-cation sample, and higher pH value of low-pressure feed water. It has been shown that with a lower concentration of Type BRW 150H reagent, the main quality indicators of feed water, boiler water, and low- and high-pressure steam are within the their standardized ranges and have stable values. It is pointed out that the specific consumption of Type BRW 150H reagent is a factor of 2 lower than in case of metering Type 906H reagent.

Thermodynamic Evaluation of Integrated Heat-Pipe Reformer SOFC System

In the presented work a medium-sized integrated system based on a sodium heat pipes powered allothermal fluidized bed gasification and SOFC is introduced, simulated and validated in Aspen Plus. Suitable feedstocks for such fluidized bed gasification systems are for example waste and biomass, especially wood. The concept development and evaluation have been conducted as part of the EU FCH-JU project SOFCOM. During the allothermal heat pipes gasification process heat for the endothermic gasification reactions is transported into the gasification chamber via the heat pipes. The heat pipes allow low temperature differences using mainly latent heat transport. Inside the heat pipes sodium is evaporated on the hot side by a heat source (i.e. combustion chamber) and condensed on the cold side (i.e. gasification chamber). Heat pipes based gasification has proven to be a reliable technology at different installations by the company Agnion energy GmbH and others. The gasifier model has been validated against data from this type of gasifier. The SOFC model applied is a thermodyamic model, which has been developed in the frame of SOFCOM and already described in detail in other works. In the presented system configuration the product gas from the gasifier is cleaned during several process steps at an intermediate temperature of 350°C. After the cleaning procedure the gas is introduced into the SOFC anode where it is converted into electricity and high temperature heat at a fuel utilization rate of 80%. At the same time preheated air is fed to the cathode of the SOFC. The SOFC exhaust is fed into a fluidized bed post combustion chamber where residual fuel is burned with residual oxygen. Heat is extracted via the heat pipes from the combustion chamber, as well as the SOFC itself. Combustion exhaust gases are used to preheat the cathode air. Residual exhaust heat is used to generate high pressure superheated steam, which in turn is expanded in a steam turbine. At this point, the steam necessary for the fluidization of the gasifier and gasification agent is not produced in a separate steam generator but instead extracted from the steam turbine. Especially by means of utilization of excess heat from the SOFC and its exhaust gases via the heat pipes and full integration of the steam cycle the electrical efficiency of the combined system reaches up to 62%LHV. Figure 1

Simulation of an Industrial Tangentially Fired Boiler Firing Metallurgical Gases

In industrial environments, boiler units are widely used to supply heat and electrical power. At an integrated steel mill, industrial boilers combust a variable mixture of metallurgical gases combined with additional fuels to generate high-pressure superheated steam. Most tangentially fired boilers have experienced water wall tube failures in the combustion zone, which are thought to be caused by some deficiency in the combustion process. The challenge faced in this present process is that there are very limited means to observe the boiler operation. In this study, a three-dimensional computational fluid dynamics (CFD) modeling and simulation of an industrial tangentially fired boiler firing metallurgical gases was conducted. Eddy dissipation combustion model was applied on this multiple fuel combustion process. Simulation results obtained from the developed CFD model were validated by industrial experiments. A quick comparison of the flame shape from the simulation to the actual flame in the boiler showed a good agreement. The flow field and temperature distribution inside the tangentially fired boiler were analyzed under the operation conditions, and a wall water tube overheating problem was observed and directly related to the flow characteristics.

Adaptive Fuzzy PID Control Applied in Boiler System of Power Plant

The boiler system in power plant consists mainly of a steam-water system and combustion system, which produce a high-pressure superheated steam to drive a generator in order to produce power. The steam temperature control of the boiler system is a critical operational consideration. Parameters of boiler producing process must be controlled strictly. But the boiler system has high nonlinearity, large delay, strong coupling and load disturbance. Therefore it is difficult to develop practical mathematical model of the control object using the traditional PID control. In order to realize the optimal control of steam temperature, this paper presents the adaptive fuzzy-PID control Strategy. Simulation results based on MATLAB show that the proposed strategy can largely improve the system response performance compared with the traditional PID control

High pressure desorption equilibrium of lignite obtained by the novel isochoric method

The most promising method of coal drying is the high pressure superheated steam drying (HPSHSD). High temperature and pressure sorptional equilibrium of lignite used in HPSHSD design is rarely available. The measurement requires either complex equipment or is time and labor consuming. In this work a novel isochoric method of high temperature and pressure desorption equilibrium measurement is described which uses a standard autoclave and easy to follow experimental procedure. Using this method the desorption equilibrium of low rank coal of Bełchatów open pit mine was measured in the range of temperatures up to 200°C and pressures up to 23.6bar. A BET type equation was fitted to the experimental data with correlation coefficient of 0.960. The results obtained compare well to the results obtained for low rank coal using much more sophisticated equipment.

高圧過熱水蒸気酸化による下水汚泥の処理と熱エネルギー回収技術の開発

高圧過熱水蒸気酸化による下水汚泥の処理と熱エネルギー回収技術の開発

Gasification and Hydrogen Production from Waste Biomass with High Pressure Superheated Steam

High pressure superheated steam above the critical temperature (374oC) and below the critical pressure (22.1MPa) of water was used to produce hydrogen gas from waste biomass efficiently. The targets are large amount of waste biomass such as livestock excrement and paper sludge. We investigated the effects of reaction temperature, pressure, time, catalyst and molar ratio of water to carbon in biomass on the decomposition efficiency of waste biomass and the productivity of hydrogen. Almost 100% of the decomposition efficiency and 1350-1550cm3 of hydrogen production per gram of dry biomass were realized in the presence of KOH catalyst at 700oC, 10MPa, 20min and 20 of molar ratio of water to carbon in biomass.

A thermoeconomic analysis of biomass energy for trigeneration

The principal objective of this study is to formulate a calculation process, based on the second law of exergy, for evaluating the thermoeconomic potential of a steam-turbine plant for trigeneration. The plant employs biomass, namely, waste wood as its energy source. Four different plant configurations are presented and assessed. ‘Their cost effectiveness is evaluated with varying economic and operating parameters’, because only the fuel price and electricity price are varied. In case 1, high pressure superheated steam generated is supplied to meet the demand for process heat as well as chilled water production in an absorption chiller. In cases 2 and 3, steam is extracted at appropriate stages of the turbine and supplied to meet the demand for process heat and chilled water production in an absorption chiller. Steam generated in case 2 produces sufficient power to meet internal demands while case 3 generates excess electricity for sale back to the utility. In case 4, low pressure saturated steam is generated to meet the demand for process heat and electricity is bought from the utilities, including those used to power an electric vapour-compression chiller. For all cases, it was found that exergy destruction is most extensive in the furnace, amounting to nearly 60%. Exergy destruction in the steam drum is the next most extensive ranging from 11% to 16%. It was also observed that the overall production cost decreases with steam pressure and increases with steam temperature.

The effect of elevated inlet air temperature and relative humidity on cogeneration system

The effect of elevated inlet air temperature and relative humidity on a gas turbine (GT) cogeneration system performance was investigated. The analysis was carried out on a GT of a capacity 171 MW at ISO condition, which is integrated with a dual pressure heat recovery steam generator (HRSG), the cogeneration system had been tested under Kuwait summer climate conditions. A computational model was developed and solved using engineering equation solver professional package to investigate the performance of a dual pressure GT-HRSG system. The suggested HRSG is capable of producing high-pressure superheated steam at 150 bar and 510°C to operate a power generation steam turbine cycle, and a medium pressure saturated steam at 15 bar to run a thermal vapor compression (TVC) desalination system. In this research, the influence of elevated inlet air temperature and relative humidity on the energy assessment of the suggested cogeneration system was thoroughly investigated. Results indicated that operating GT under elevated values of inlet air temperatures is characterized by low values of net power and thermal efficiency. At elevated inlet air temperatures, increasing relative humidity has a small positive impact on GT cycle net power and thermal efficiency. Integrating the GT with HRSG to generate steam for power generation and process heat tends to increase energy utilization factor of the system at elevated inlet air temperatures. Increasing inlet air temperature plays a negative impact on power to heat ratio (PHR), while relative humidity has no effect on PHR. Copyright © 2009 John Wiley & Sons, Ltd.

Gasification and Hydrogen Production from Food Wastes Using High Pressure Superheated Steam in the Presence of Alkali Catalyst

We studied the hydrogen production from four kinds of wet food wastes using high pressure superheated steam, which is reactive water above the critical temperature and below the critical pressure of water. 1.8–2.0 mmoles of hydrogen gas were produced from 1 mmole of organic carbon in the wastes at 700°C, 10 MPa, 30 min, 20 of the molar ratio of water to organic carbon and 20 wt% of the potassium hydroxide to the organic content in the waste. The production of hydrogen gas was accelerated by increasing the temperature and molar ratio of water to organic carbon in the waste, but suppressed by increasing the pressure. On the other hand, the production of ammonia, which is a typical by-product of gasification of food wastes, reduced by increasing the temperature and decreasing the pressure. Judging from the experimental results, high pressure superheated steam with low pressure was more effective than supercritical water with high pressure. The calculated equilibrium mole fractions of hydrogen gas based on the ideal gas assumption agreed with the experimental data in wide temperature and pressure regions, but those of methane and carbon dioxide deviated from the data above 600°C.

CO<sub>2</sub>回収を部分的に行う多重熱利用サイクル発電システムの構成と特性

A multi-cascade heat utilizing power generation system is proposed in which carbon dioxide (CO2) generated is partially recovered by adopting the oxygen (O2) combustion method. In the system, a gas turbine is driven by high-temperature working fluid (air) generated by burning fuel. The turbine outlet gas, which has still considerable energy, is used to generate high-pressure super-heated steam and middle-pressure one at a waste heat boiler (WHB). The high-pressure steam is used for driving an expansion turbine, until its pressure becomes the same as the one of the middle-pressure super-heated steam produced at the WHB. Both the middle-pressure steams are utilized as the working fluid of the CO2-recovering non-polluting high-efficiency gas turbine power generation system, in which the heat energy is also utilized cascade-wisely. It was shown that the system had the net power generation efficiency of 48.4% at the lower calorific value base with CO2 recovery rate of 30.1%, and that this efficiency was remarkably high compared with that of a convensional combined-cycle power generation sys-tem in which a CO2 recovery process is incorporated so as to attain the same CO2 recovery rate.

A study of the uptake of salts from high pressure superheated steam by AISI type 316 stainless steel

The deposition of NaCl, NaBr and NaOH on the surface of AISI Type 316 stainless steel tube from solution in superheated steam at concentrations of 6–4000 μg kg −1, a pressure of 17.6 MPa (2550 lb in −2) and 673 and 773 K has been studied using the radiotracers 24Na, 28Cl and 82Br in a purpose-built loop at a Reynolds number of ca 4000. Very small amounts of 38Cl and 83Br were taken up, showing that the salts were hydrolysed at the tube surface. The amount of sodium taken up could be explained by turbulent diffusion to the walls and incorporation in the growing oxide film; it was resistant to removal by washing.

Rupture strength in steel 1kh14n14v2m in high-pressure steam

1. High-pressure superheated steam (580, 185 at.) causes the rupture strength and ductility of steel 1Kh14N14V2M to decrease slightly. 2. The specimens tested in high-pressure steam are affected by a higher number of cracks than those tested in air. In both eases the cracks extend along the grain boundaries.

Once-Through Series Boiler for 1500 to 5000 Lb. Pressure

Abstract The paper covers the development of series-type boilers from the early stages which resulted in the Calumet steaming economizer type now in extensive use to the once-through series boiler. It describes the operation of the latter units from 1500 to 5000 lb. per sq. in., and test data are given. The limiting factors of this type of unit, such as equalization of flow, control with variable capacity, and operation, are discussed. Heat-transfer data on high-pressure superheated steam are presented.