电站锅炉高温集箱变形分析

电站锅炉高温集箱变形原因多种多样,某化工企业流化床锅炉集箱变形,通过现场变形程度测量、查阅资料、变形程度判定、集箱的金相检测、硬度检测、化学成分分析、胀粗测量以及有限元建模分析等手段分析变形的原因,给出处理方案,并针对缺陷原因,采取了补救性改造,通过运行实践看,改造效果良好。经改造后复检,未再发现异常变形情况。给出变形原因为锅炉设计人员改进设计提供借鉴,为类似缺陷的发生提供分析、处理和解决方案。     

Ultrasupercritical power plant development and high temperature materials applications in China

Abstract

The rapid development of Chinese economy demands sustainable growth of power generation to meet industrial and domestic demand. The total installed capacity of electricity and annual overall electricity generation are now both the second highest in the world, close to those of the USA. Forecasts of China's electricity demand over the period 2010–20 are presented. Chinese power plants, like those worldwide, are facing demands to increase thermal efficiency and to decrease the emission of CO₂, SO_X and NO_X. In light of the national resource of coal and electricity market requirements in the next 15 years, power generation – especially ultrasupercritical (USC) power plants with the steam temperature over 600°C – will undergo rapid development. The first 1000 MW USC power unit, with steam parameters 600°C, 26·25 MPa, entered service in November 2006. It is estimated that more than 350 USC power units will be installed in China by 2020. USC power plant designs will adopt a variety of qualified high temperature materials for boiler and turbine manufacturing applications. Among these materials, the modified 9–12%Cr ferritic steels, Ni–Cr austenitic steels and certain nickel base superalloys have received special attention in the Chinese materials market.     

Hydrogen production by high temperature,high pressure water electrolysis,results of test plant operation

A high temperature, high pressure water electrolyzer has been developed. A test plant was built with a hydrogen production capacity of 4 m³ h^?1, operating at 120°C and 20 kg cm^?2 G. The development of the test plant was reported previously. The test plant was operated for 22 months under various operating conditions and with various combinations of electrodes. Of the electrodes, a high surface area nickel electrode showed the best results, its cell voltage being 1.64 V at 102°C and 400 mA cm^?2. PTFE impregnated with a Ti compound was used as the diaphragm material. The operating pressure did not show much effect on cell voltage.     

Uncertainties in the evaluation of high temperature damage in power stations and petrochemical plant

Some of the areas of uncertainty in the evaluation of high temperature damage are examined. These uncertainties must be reduced as much as possible in order to predict the remaining safe life of plants accurately. Specific topics discussed include the localized nature of damage; the nature of high temperature damage in steam generators involving mechanisms other than creep; the nature of the ‘cavitation’ frequently observed as creep damage, and the methods of evaluating it; and methods of predicting the extent of damage in reformer tube furnaces.     

高温热管在小氮肥余热回收中的应用

将高温热管蒸汽发生器应用于小氮肥造气工艺,以取代原普通余热锅炉回收煤气工段的高温余热,解决了合成氨生产工艺中煤气降温的难题,取得了很好的经济效益和社会效益。     

Life Cycle Assessment of a high temperature molten salt concentrated solar power plant

Realizing and installing renewable energy plants have an environmental “footprint” that has to be evaluated to quantify the real impact of renewable technologies on the environment. Nowadays, the most important tool to evaluate this impact of a product is the Life Cycle Assessment (LCA).The aim of this work is to present a Life Cycle Assessment of an innovative solar technology, the molten salt concentrating solar power (CSP) plant combined with a biomass Back-Up Burner, developed by Italian Research Centre ENEA and able to produce clean electricity by using solar energy. The Life Cycle Assessment was carried out by means of the SimaPro7 software, one of the most used LCA software in the world.In the second part of the study the environmental performance of the CSP plant was compared with these of conventional oil and gas power plants.     

Transient analysis of coupled high temperature nuclear reactor to a thermochemical hydrogen plant

A very high temperature reactor (VHTR) has been considered for generation of hydrogen by water-splitting through thermochemical processes using process heat. The development of this technology requires understanding of the coupled behavior of VHTR and the hydrogen generation plants and key safety issues during transients. A system level modeling of the coupled VHTR and sulfur-iodine hydrogen generation process is carried out where the thermal and neutronic models of the VHTR and the chemical models of the sulfur-iodine cycle were developed and benchmarked with available experimental data, models and simulation codes. Transient analysis of the possible accidents emanating either from VHTR or hydrogen plants was carried out. The results indicate that on VHTR side the response of the reactor is affected by the temperature feedback and xenon buildup feedback. On the hydrogen plant side the slowest reaction controlled the speed of the overall response of the chemical plant.     

Thermodynamic analysis of a hard coal oxyfuel power plant with high temperature three-end membrane for air separation

Cryogenic air separation is a mature state-of-the-art technology to produce the high tonnage of oxygen required for oxyfuel power plants. However, this technology represents an important burden to the net plant efficiency (losses between 8% and 12%-points). High temperature ceramic membranes, associated with significantly lower efficiency losses, are foreseen as the best candidate to challenge cryogenics for high tonnage oxygen production. Although this technology is still at an embryonic state of development, the three-end membrane operation mode offers important technical advantages over the four-end mode that can be a good technological option in the near future.     

某企业自备热电厂高温高压机组节能改造研究

针对国内某洗涤用品企业自备热电厂锅炉热效率低、汽轮机汽耗率高以及企业实际用电情况,把原35t/h中温中压循环流化床锅炉及配套背压汽轮发电机组改为40t/h高温高压锅炉及配套反动式高转速汽轮发电机组(西门子技术)后,锅炉热效率提高了8个百分点,平均汽耗率降至8.3kg/k Wh,相同供热条件下,热电厂每年多供电1800多万k Wh,取得了较好的节能效果,为企业节约了燃煤及外购电成本。     

Component life assessment methods for nuclear power plant

Aging is a natural phenomenon which leads to degradation of the materials, components, and structures to various degrees as the age of an engineering plant increases. Life extension of aged components beyond the design life has to be based on detailed assessment methods for these components. In this paper, the life assessment methods for nuclear power plant components are reviewed, in which the key components such as reactor pressure vessels (vessel plates, nozzles, and internals), pipings, steam turbine rotors, condensers, heaters, and valves, etc., are emphasized. Each component is evaluated based on its major aging mechanism, followed by the regulatory requirements, design code, literature/experimental data, and statistics of operation histories. Comments on the aging processes reviewed in the EPRI Industry Reports (IRs) are also referred to in this paper.     

某电厂锅炉高温再热器异种钢焊口断裂原因分析

分析了锅炉高温再热器焊口产生断裂的原因,锅炉停炉时产生交变应力,钢管产生裂纹,并发生脆性断裂。     

Crosslinked SPES-SPPSU membranes for high temperature PEMFCs

Highly sulfonated polyethersulfone (SPES; Ione exchange capacity = 3.2 meq/g) and polyphenylsulfone (SPPSU; ion exchange capacity = 3.2 meq/g) were synthesized. To get high thermal and chemical stability, a blend membrane was prepared by the composite of SPES and SPPSU. The SPES-SPPSU blend membrane after the annealing treatment at 180 °C was stable in water and other organic solvents, and the thermal stability was also more increased than that of pristine SPES and SPPSU polymers due to the crosslinking formation among SPES and SPPSU. The maximum conductivity of 0.12 S/cm was obtained at the temperature of 140 °C and RH 90%.     

Performance assessment of a solar hydrogen and electricity production plant using high temperature PEM electrolyzer and energy storage

This paper investigates the performance of a high temperature Polymer Electrolyte Membrane (PEM) electrolyzer integrated with concentrating solar power (CSP) plant and thermal energy storage (TES) to produce hydrogen and electricity, concurrently. A finite-time-thermodynamic analysis is conducted to evaluate the performance of a PEM system integrated with a Rankine cycle based on the concept of exergy. The effects of solar intensity, electrolyzer current density and working temperature on the performance of the overall system are identified. A TES subsystem is utilized to facilitate continuous generation of hydrogen and electricity. The hydrogen and electricity generation efficiency and the exergy efficiency of the integrated system are 20.1% and 41.25%, respectively. When TES system supplies the required energy, the overall energy and exergy efficiencies decrease to 23.1% and 45%, respectively. The integration of PEM electrolyzer enhances the exergy efficiency of the Rankine cycle, considerably. However, it causes almost 5% exergy destruction in the integrated system due to conversion of electrical energy to hydrogen energy. Also, it is concluded that increase of working pressure and membrane thickness leads to higher cell voltage and lower electrolyzer efficiency. The results indicate that the integrated system is a promising technology to enhance the performance of concentrating solar power plants.     

Cover systems for high temperature flat-plate solar collectors

A simulation study has been conducted of the influence of cover design on the thermal performance of flat-plate solar collectors for use at temperatures of 150°C. Detailed results are presented of the effects of changes in cover materials, cover surface treatments, cover system configuration and absorber plate surface treatments on both the instantaneous efficiency and the long term solar contribution of flat-plate collectors. For the simulation conditions, it is shown that flat-plate collectors consisting of a single high transmittance cover, a convection suppressing device such as a honeycomb and a selective absorber surface yield long term solar contributions comparable to those of evacuated tubular collectors, whereas other configurations simulated (single and multiple cover systems) are significantly inferior.     

Economic and environmental competitiveness of high temperature electrolysis for hydrogen production

Alternative hydrogen production technologies are sought in part to reduce the greenhouse gas (GHG) emissions intensity compared with Steam Methane Reforming (SMR), currently the most commonly employed hydrogen production technology globally. This study investigates hydrogen production via High Temperature Steam Electrolysis (HTSE) in terms of GHG emissions and cost of hydrogen production using a combination of Aspen HYSYS® modelling and life cycle assessment. Results show that HTSE yields life cycle GHG emissions from 3 to 20 kg CO_2e/kg H₂ and costs from $2.5 to 5/kg H₂, depending on the system parameters (e.g., energy source). A carbon price of $360/tonne CO_2e is estimated to be required to make HTSE economically competitive with SMR. This is estimated to potentially decrease to $50/tonne CO_2e with future technology advancements (e.g., fuel cell lifetime). The study offers insights for technology developers seeking to improve HTSE, and policy makers for decisions such as considering support for development of hydrogen production technologies.     

Improved durability of SOEC stacks for high temperature electrolysis

An experimental study has been conducted at Idaho National Laboratory to demonstrate recent improvements in long-term durability of solid oxide electrolysis cells (SOEC) and stacks. Results of five stack tests are presented. Electrolyte-supported SOEC stacks were provided by Ceramatec Inc. and electrode-supported SOEC stacks were provided by Materials and Systems Research Inc. (MSRI), for these tests. Long-term durability tests were generally operated for durations of 1000 h or more. Stack tests based on technologies developed at Ceramatec and MSRI have shown significant improvement in durability in the electrolysis mode. Long-term degradation rates of 3.2%/khr and 4.6%/khr were observed for MSRI and Ceramatec stacks, respectively. One recent Ceramatec stack even showed negative degradation (performance improvement) over 1900 h of operation. Optimization of electrode and electrolyte materials, interconnect coatings, and electrolyte–electrode interface microstructures contribute to improve the durability of SOEC stacks.     

PFBC中试电站的几种特殊检测方法

文章介绍了PFBC增压泫化床中试电站锅炉密相区的温度、压力、压差测试和料位测试方法等。这些检测方法可供AFBC锅炉等作参考。     

Thermodynamic calculation and reference electrode calibration for high temperature molten salts

Abstract

Molten salts are important reaction media for chemical and electrochemical processing and have recently attracted attention for their potential in reprocessing and partitioning spent nuclear fuels. Electrochemical measurements are a convenient tool for exploring thermodynamic and kinetic properties of molten salts, but inconsistency in acquired data may arise from the use of inaccurate reference electrodes and differences in thermodynamic calculations. A thermodynamic approach to the calculation of half cell potentials for reactions in molten salts is proposed. As examples, chlorine/chloride and lithium ion/lithium half cell potentials in LiCl–KCl eutectic are thermodynamically analysed. The Ag/AgCl reference electrode is discussed as an example of a high temperature reference electrode. A technique involving in situ transient reduction of constitutive metal ions for the calibration of high temperature reference electrodes is developed which may enable the consistency of acquired data using different reference electrodes in a variety of molten salts. The thermodynamic approach and calibration technique may be extended to ionic liquid and other media at high and low temperatures.     

Concepts and design for scaling up high temperature water vapour electrolysis

Based upon laboratory high temperature electrolysis experiments with single cells and serial connected electrolysis cells a concept for scaling up the system for technical applications is presented. It is shown that with regard to the specific properties of ceramic materials a tubular geometry for the electrolysis cells will be most appropriate. In contrast to flat plate cells, tubular cells can easily be connected in series with respect to electrical current as well as gas flow.A scheme for the integration of electrolysis tubes into modules and large scale electrolysis plants will be presented.With respect to the process engineering of an industrial electrolysis plant, it is shown that a near term realization is possible, without high temperature heat sources, by a slightly exothermic operation of the electrolysis cells.