过程装备与控制工程外文文献翻译

17th World Conference on Nondestructive Testing, 25-28 Oct 2008, Shanghai, ChinaA new fully digital system for RT inspection of metal tube to tube sheet jointsof heat exchangersUwe ZSCHERPEL 1, Oleksandr ALEKSEYCHUK 1, Peter ROST 2, Markus SCHMID 2, Konstantinos SPARTIOTIS 3, Alexander WARRIKHOFF 41 Division “NDT – Radiology”, BAM Berlin, GermanyPhone: +49 30 8104 3677, Fax: +49 30 8104 4657; e-mail: uwez@bam.de,oleksandr.alekseychuk@bam.de2 BASF SE; Ludwigshafen, Germany; e-mail: peter.rost@, markus.schmid@3 AJAT Oy, Espoo, Finland; e-mail: kostas@ajat.fi4 rtw RÖNTGEN-TECHNIK DR. WARRIKHOFF GmbH, Neuenhagen, Germany; email:sales@rtwxray.deAbstractA completely novel device was developed for RT inspection of weldments for tube to tube sheet joints on heat exchangers applied in chemical industry. It replaces the Gammamat B3 unit containing an Ir 192 isotope as radiation source and a punched NDT film (system class C3 acc. to EN 584) as detector to allow the one-sided access for inspection.In a first step a special X-ray tube with a rod anode was developed by rtw Röntgentechnik to replace the Ir 192 isotope source to achieve a better inspection sensitivity at 130 kV for thin walled tubes and tube sheets.A new specialized, direct converting detector based on CdTe was designed by Ajat Oy, Finland. Together with the X-ray source a handsome unit was designed with 4 detector tiles arranged around the rod anode, which passes though the detector plane.The handling of this novel inspection unit as well as the computer based image acquisition reduces the expense for this RT inspection considerably. All problems with film chemistry and isotope transportation are avoided. The computer based evaluation of the digital radiographs and the direct connection to the inspection data base of the complete heat exchanger create significant advantages for inspection planning and documentation. First experiences are reported on application of this new technique in the field.Key words: Radiographic inspection, digital detector arrays, one-sided access, tube to tube sheet joints, heat exchangers, chemical industry1.Conventional Inspection TechniqueSince decades state of the art is radiographic testing based on Gammamat B3 containing an Ir 192 isotope as radiation source and NDT film (typically system class C3 acc. to EN 584-1) as detector (see fig. 1). For this application packed films have to be punched light tight to pass the radio isotope source through the imaging plane caused by the one-sided accessibility of the tube sheet. Special wall thickness compensators are used to account for wall thickness changes in penetrating direction across the inspected weld regions. The sensitivity of this testing method is limited by the properties of the radiation source (energy and source size). Also the world wide shipment of radio isotopes gets more and more complicated.Fig.1: Gammamat B3 isotope source with film holder (left side) at inspection position and set-up for inspection of a small heat exchanger in the field (right side)The design, production and inspection of tube-to-tube sheet welds are regulated in the BASF specification E-S-MC 331. For high risk heat exchangers additional inspections by the owner of the heat exchanger (BASF) are required and realize the surveillance of the manufacturing during heat exchanger built-up. The specification requires random tests depending on the mechanical and thermal load of the heat exchanger (in percentage of welds to be tested and acceptance criteria for detected indications) on behalf of the future owner BASF. Depending on the results of the first random test a second random test after repair or a 100% test charged to the manufacturer may be necessary to reach the required weld quality.Typical source size is 1x0.5mm² Ir-192 isotope and 10x12 cm² punched C3 films are used with 0.02 mm Lead screens. The range of inspected tubes is from 16mm x 1.5mm up to 76mm x 4mm (diameter x wall thickness), pore sizes down to 1mm can be detected with this configuration.Fig.2: film exposure (left above) and corresponding cross sections by destructive testing (right side) showing typical flaws like porosities and notches2.The new rod anode X-ray tube /1/A new X-ray tube was developed by rtw Röntgentechnik Dr. Warrikhoff to achieve a better inspection sensitivity and to solve issues with world wide transport of radio isotopes. In Fig. 3this tube is shown. The main reason for this development was the limited detectability with Ir 192. Caused by the energy of the gamma rays the minimal detectable pore size is about 0.8mm in steel. For new materials like Ti enhanced flaw detection was requested.Fig. 3:Rod anode X-ray tube MCTS 130 - 0.6 (left side) and complete inspection setup with controller, right side: HV generator and X-ray tube with film holder (red) at a heat exchanger ready for single-sided inspectionThe rod has an outer diameter of 6 mm and a length of 40 mm, the focal spot is smaller than 1mm at 130kV and 2.4mA (max. 300 W). This new tube was successfully applied in combination with X-ray film and the enhanced detectability for new materials like Ti was proven, so the next step to replace the film was straight forward to omit the necessary chemical development procedure on-site.3.The digital detector array DIC100TH /2/Ajat developed the detector DIC100TH, which is a first of its kind, breakthrough digital imaging device for tube to tube-sheet weld inspection.The detector comprises four 25 mm x 25 mm CdTe-CMOS high resolution elements (100µm pixel size) operating at 50fps and arranged to allow a rod anode tube to pass through the mid-section of the device. The X-Rays are produced at the tip of the rod anode and emit in a direction towards the CdTe-CMOS detector (see fig. 4).The rod-anode tube is fed through the CdTe-CMOS active detector and the two are bound together in a robust mechanical arrangement which can be inserted in the heat exchanger for the tube to tube-sheet weld to be inspected (fig. 5).This image sensor provides for real time and on line tube to tube sheet weld inspection with excellent sensitivity, reliability and speed. The unit addresses requests to replace the traditional film based systems that today are used typically in this field with a real time digital inspection system.The basic spatial resolution and detector calibration limits the maximum contrast sensitivity of the detector. The basic spatial resolution is 100 µm for this direct converting detector and defined by the pixel size. To achieve the best detection sensitivity possible a special calibration procedure was developed. Caused by the strong dependence of X-ray intensity on the radial distance form the rod centre the rod anode X-ray tube cannot be used for pixel calibration of the detector. Also the temperature dependence of the detector calibration is not neglectable. As result of the developed calibration procedure (using a standard X-ray tube at 90kV, 1m distance and a 5 mm steel plate at the detector to generate a suitable flat field for detector calibration) calibrationsets are stored in dependence of the detector temperature in the range between 10°C and 32°C and selected automatically according to the real detector temperature in the field. In this manner the optimal detector calibration is maintained in the field.Fig. 4:The digital detector array DIC 100TH, left side: detector electronics showing the arrangement of the 4 detector tiles around the rod anode X-ray tube, right side: detector-X-ray unit ready for single-sided inspectionFig. 5: The fully digital inspection system with its two main parts (left side) and installed at a heat exchanger ready for inspection4.Software, complete inspection system and first resultsIn fig. 6 a snapshot of the developed user interface of the software is shown. A Laptop equipped with a Cameralink interface for detector connection and an RS-422 interface for control of the X-ray generator is used for image storage, evaluation and report generation. The complete system (X-ray tube and detector) is software controlled and complete configuration set-ups can be stored and re-activated for easiest handling. A list with inspection results is transferred directly to the data base “virtual tube” for documentation of the inspection. Digital filters can be applied for enhancement of flaw detection on the display.Fig. 6:snapshot of the developed software for system control, left side: image display and interactive selection of inspection result, middle: control program for X-ray tube set-up, integration time and description of inspection position, right side: visualization of inspection result summery for the whole heat exchanger (based on the data base virtual tube)A comparison of the achieved detection limits for the novel inspection systems is shown in fig. 7 based on a test mock-up with 25mm diameter pipes and 2mm steel wall thickness.Fig. 7: Comparison of inspection results on a steel test mock-up 25x2mm, left side: conventional system with Ir 192 and film, detection limit 0.8mm drill hole, middle: rod anode and film, detection limit 0.5mm drill hole, right side: rod anode and DIC100TH detector, detection limit better than 0.3mm drill hole.In fig. 8 an example of a real inspection result for a 25mm steel pipe with 2mm wall thickness is given. The visibility of the flaw indications can be improved by digital image processing of the images acquired from the detector.Fig. 8: comparison of inspection results of a real weldment on a heat exchanger 25mm/2mm at 80kV, 0.5mA and 30s exposure, left side: rod-anode and X-ray film, right side: DIC100TH detector and highpass filtering of digital imageField trials are on-going to gain experience with this novel inspection system and to prove the advantages and the extended application range in comparison with the classical set-up.5.ConclusionsAn improved inspection system for RT inspection of metal tube to tube sheet joints of heat exchangers was developed based on a unit combining a rod anode X-ray tube and a new digital detector array arranged in tiles around this rod anode. In this way the single-sided access for weld inspection was realized. The following advantages of this novel fully digital unit were proven: •no radioactive container transport and usage of film chemistry on-site at the heat exchanger production site•improved flaw detection•shorter inspection times•immediate inspection result•software supported evaluation of images•data base supported documentation of inspection results•reduced requirements for radiation protection, considerable smaller controlled area with75 kV X-ray voltage compared with Ir-192 requirements as used beforeThe experiences gained with the presented prototype system will result in optimised follow-up inspection systems.6.References/1/ www.rtwxray.de/2/ www.ajat.fi。

5
The design of chemical reactors is probably the one activity which is unique to chemical engineering, and it is probably this function more than anything else which justifies the existence of chemical engineering as a distinct branch of engineering.
Physical treatment Steps
Produces

Recycle
1
The raw materials undergo a number of physical treatment steps to put them in the form in which they can be reacted chemically. They then pass through the reactor.The products of the reaction must then undergo further physical treatment- separations, purifications, etc. - for the final desired product to be obtained. 原料进行了一些物理处理的步骤，使它们能够发 生化学反应。然后让他们通过反应器。产物要经 历进一步的物理处理——分离，净化提纯等等， 以获得期望的最终产品。
只有……才有的 化学反应器的设计也许是一种只有化学工程领域才涉及 的工作。并且可能正是因为这种功能才奠定了化学工程 作为工程领域的一个特殊分支而存在的合理性

Principles of Mass Transfer1. General RemarksSome of the most typical chemical engineering problems lie in the field of mass transfer. A distinguishing mark of the chemical engineer is his ability to design and operate equipment in which reactants are prepared, chemical reactions take place, and separations of the resulting products are made. This ability rests largely on a proficiency in the science of mass transfer.Applications of the principles of momentum and heat transfer are common in many branches of engineering, but the application of mass transfer has traditionally been largely limited to chemical engineering. Other important applications occur in metallurgical processes, in problems of high-speed flight, and in waste treatment and pollution-control processes.By mass transfer is meant the tendency of a component in a mixture to travel from a region of high concentration to one of low concentration. For example, if an open test tube with some water in the bottom is placed in a room in which the air is relatively dry, water vapor will diffuse out through the column of air in the test tube. There is a mass transfer of water from a place where its concentration is high (just above the liquid surface) to a place where its concentration is low (at the outlet of the tube). If the gas mixture in the tube is stagnant, the transfer occurs by molecular diffusion. If there is a bulk mixing of the layers of gas in the tube by mechanical stirring or because of a density gradient, mass transfer occurs primarily by the mechanism of forced or natural convection. These mechanisms are analogous to the transfer of heat by conduction and by convection; there is, however, no counterpart in mass transfer for thermal radiation.The analogy between momentum and energy transfer has already been studied in some detail, and it is now possible to extend the analogy to include mass transfer.In discussing the fundamentals of mass transfer we shall consider mainly binary mixtures, although multicomponent mixtures are important in industrial applications. Some of these more complicated situations will be discussed after the basic principles have been illustrated in terms of binary mixtures,2. Molecular DiffusionMolecular diffusion occurs in a gas as a result of the random motion of the molecules. This motion is sometimes referred to as a random walk. Across a plane normal to the direction of the concentration gradient (or any other plane), there are fluxes of molecules in both directions. The direction of movement for any one molecule is independent of the concentration in dilute solutions. Consequently, in a system in which there is a concentration gradient, the fraction of molecules of a particular species (referred to as species A) which will move across a plane normal to the gradient is the same for both the high-and low-concentration sides of the plane. Because the total number of molecules of A on the high-concentration side is greater than on the low-concentration side, there is therefore a net movement of A in the direction in which the concentration of A is lower. If there are no counteracting effects, the concentrations throughout the mixture tend to become the same. In the analogous transfer of heat in a gas by conduction, the distribution of hotter molecules (those which have a higher degree of random molecular motion) tends to be evened out by random mixing on a molecular scale. Similarly, if there is a gradient of directed velocity (as distinguished from random velocity) across the plane, the velocity distribution tends toward uniformity as a result of the random molecular mixing. There is a transfer of momentum, which is proportional to the viscosity of the gas.The above remarks apply only in an approximate and qualitative way. The quantitative prediction of the diffusivity, thermal conductivity, and viscosity of a gas from a knowledge of molecular properties can be quite complicated. The consideration of such relations forms an important part of the subject of statistical mechanics.Molecular diffusion also occurs in liquids and solids. Crystals in an unsaturated solution dissolve, with subsequent diffusion away from the solid-liquid interface. Diffusion in solids is of importance in metallurgical operations. When iron which is unsaturated with respect to carbon is heated in a bed of coke, the concentration of the carbon near the surface is increased by inward diffusion of carbon atoms.3. E ddy DiffusionJust as momentum and energy can be transferred by the motion of finite parcels of fluid, so mass can be transferred. We have seen that the rate of these transfer operations, caused by bulk mixing in a fluid, can be expressed in terms of the eddy kinematics viscosity, the eddy thermal diffusivity, and the eddy diffusivity. This latter quantity can be related to a mixing length which is the same as that defined in connection with momentum and energy transfer. In fact, the analogy between heat and mass transfer is so straightforward that equations developed for the former are often found to apply to the latter by a mere change in the meaning of the symbols.Eddy diffusion is apparent in the dissipation of smoke from a smokestack. Turbulence causes mixing and transfer of the smoke to the surrounding atmosphere. In certain locations where atmospheric turbulence is lacking, smoke originating at the surface of the earth is dissipated largely by molecular diffusion. This causes serious pollution problems because mass is transferred less rapidly by molecular diffusion than by eddy diffusion.4. C onvective Mass-Transfer CoefficientsIn the study of heat transfer we found that the solution of the differential energy balance was sometimes cumbersome or impossible, and it was convenient to express the rate of heat flow in terms of a convective heat-transfer coefficient by an equation like)(m s t t h Aq -= The analogous situation in mass transfer is handled by an equation of form)(Am As P A k N ρρ-=The mass flux NA is measured relative to a set of axes fixed in space. The driving force is the difference between the concentration at the phase boundary (a solid surface or a fluid interface) and the concentration at some arbitrarily defined point in the fluid medium. The convective coefficient kp may apply to forced or natural convection; there are no mass-transfer counterparts for boiling, condensation, or radiation heat-transfer coefficients. The value of kp is a function of the geometry of the system and the velocity and properties of the fluid, just as was the coefficient h.(Selected from* C. O. Bennett, and J. E. Myens, Momentum, Heat, and Mass Transfer, 2nd Edition, McGraw-Hill Inc. , 1974. )传质原理1. 概述一些典型的化学工程问题存在于传质领域。

专业英语翻译（楠哥）Reading Material 16Pressure Vessel CodesHistory of Pressure Vessel Codes in the United States Through the late 1800s and early 1900s, explosions in boilers and pressure vessels were frequent. A firetube boiler explosion on the Mississippi River steamboat Sultana on April 27, 1865, resulted in the boat’s sinking within 20 minutes and the death of 1500 soldiers going home after the Civil War. This type of catastrophe continued unabated into the early 1900s. In 1905, a destructive explosion of a firetube boiler in a shoe factory in Brockton, Massachusetts, killed 58 people, injured 117 others, and did $ 400000 in property damage. In 1906, another explosion in a shoe factory in Lynn, Massachusetts, resulted in death, injury, and extensive property damage. After this accident, the Massachusetts governor directed the formation of a Board of Boiler Rules. The first set of rules for the design and construction of boilers was approved in Massachusetts on August 30, 1907. This code was three pages long.In 1911, Colonel E. D. Meier, the president of the American Society of Mechanical Engineers, established a committee to write a set of rules for the design and construction of boilers and pressure vessels. On February 13, 1915, the first ASME Boiler Code was issued. It was entitled “Boiler Construction Code, 1914 Edition.”This was the beginning of the various sections of the ASME Boiler and Pressure Vessel Code, which ultimately became Section 1, Power Boiler.The first ASME Code for pressure vessels was issued as “Rules for the Construction of Unfired Pressure Vessels, ”Section Ⅷ, 1925 edition. The rules applied to vessels over 6 in. in diameter, volume over 1.5 ft3, and pressure over 30 psi. In December 1931, a Joint API-ASME Committee was formed to develop an unfired pressure vessel code for the petroleum industry. The first edition was issued in 1934. For the next 17 years, two separated unfired pressure vessel codes existed. In 1951, the last API-ASME Code was issued as a separated document. In 1952, the two codes were consolidated into one code-the ASME Unfired Pressure Vessel Code,Section Ⅷ. This continued until the 1968 edition. At that time, the original code became Section Ⅷ, Division 1, Pressure Vessels, and another new part was issued, which was Section Ⅷ, Division 2, Alternative Rules for Pressure Vessels.The ANSI/ASME Boiler and Pressure Vessel Code is issued by the American Society of Mechanical Engineers with approval by the American National Standards Institute (ANSI) as an ANSI/ASME document. One or more sections of the ANSI/ASME Boiler and Pressure V essel code have been established as the legal requirements in 47 states in the United States and in all provinces of Canada. Also, in many other countries of the world, the ASME Boiler and Pressure Vessel Code is used to construct boilers and pressure vessels.Organization of the ASME Boiler and Pressure Vessel Code The ASME Boiler and Pressure Vessel Code is divided into many sections, divisions, parts, and subparts. Some of these sections relate to a specific kind of equipment and application; others relate to specific materials and methods for application and control of equipment; and others relate to care and inspection ofinstalled equipment. The following Sections specifically relate to boiler and pressure vessel design and construction.Section ⅠPower Boilers (1 volume)Section ⅢDivision 1 Nuclear Power Plant Components (7 volumes)Division 2 Concrete Reactor Vessels and Containment (1 volume)Code Case Case 1 Components in Elevated Temperature service (in Nuclear Code N-47 Case book)Section ⅣHeating Boilers (1 volume)Section ⅧDivision 1 Pressure Vessels (1 volume)Division 2 Alternative Rules for Pressure Vessels (1 volume )Section ⅩFiberglass-Reinforced Plastic Pressure Vessels (1 volume)A new edition of the ASME Boiler and Pressure Vessel Code is issued on July 1 every three years and new addenda are issued every six months on January 1 and July 1. the new edition of the code becomes mandatory when it appears. The addenda are permissive at the date of issuance and become mandatory six months after that date.Worldwide Pressure Vessel Codes In addition to the ASME Boiler and Pressure Vessel Code, which is used worldwide, many other pressure vessel codes have been legally adopted in various countries. Difficulty often occurs when vessels are designed in one country, built in another country, and installed in still a different country. With this worldwide construction this is often the case.The following list is a partial summary of some of the various codes used in different countries:Australia Australian Code for Boilers and Pressure Vessels, SAA Boiler Code (Series AS1200): AS1210, Unfired Pressure Vessels and Class 1 H, Pressure Vessels of Advanced Design and Construction, Standards Association of Australia.France Construction Code Calculation Rules for Unfired Pressure V essels, Syndicat National de la Chaudronnerie et de la Tuyauterie Industrielle (SNCT), Paris, France.United Kingdom British Code BS.5500, British Standards Institution, London, England.Japan Japanese Pressure V essel Code, Ministry of LABOR, PUBLISHED BY Japan Boiler Association, Tokyo, Japan; Japanese Standard, Construction of Pressure Vessels, JIS B Gas Control Law, Ministry of International Trade and Industry, published by The Institution for Safety of High Pressure Gas Engineering , Tokyo, Japan.Italy Italian Pressure Vessel Code, National Association for combustion Control (ANCC), Milan, Italy.Belgium Code for Good Practice for the Construction of Pressure Vessels, Belgian Standard Institute (IBN), Brussels, Belgium.Sweden Swedish Pressure Vessel Code, Tryckkarls Kommissioner, the Swedish Pressure Vessel Commission, Stockholm, Sweden.压力容器规范美国压力容器规范的历史从19世纪末到20世纪初，锅炉和压力容器的爆炸是常有发生。