Tube explosion

Use Coating nuclear fuel rods, corrosion-resistant alloys, photo flashbulbs (foil), pyrotechnics, metal-to-glass seals, special welding fluxes, getter in vacuum tubes, explosive primers, acid manufacturing plants, deoxidizer and scavenger in steel manufacturing, laboratory crucibles, spinnerettes. 

The main components used 150 cm long, diameter of 7 cm hard glass tube explosion, tungsten rod ignition electrode diameter is 1.5 mm, pressure gauge, flow meter, circulating pump, etc. 

Kinetic energy transfer—shock tube, explosive charge, impact... 

Hitachi recommends applying low pH coordinated phosphate treatment for natural circulation boilers as Hitachi s standard for the following reasons. Hitachi has experienced water wall tube explosions that originated in hard zinc scale adhesion. It was thought that zinc dissociated from condensation tubes of copper alloy and deposited on water wall tubes. 

Table A.4 [1] shows the analysis results of scale withdrawn from the tubes after a tube explosion of Boiler A (described in Table A.3 [1]). The main component was zinc, approximately 30% copper and nickel were also contained at nearly 10% each.

B 17.1 Heavy oil only Volatile or equivalent Tube explosion... 

Following a series of flame computations over an extended range of initial compositions and conditions, the validity of an assumed kinetic mechanism and set of rate parameters may be tested by comparison of computed properties with experiment. In the case of the flame profiles there must be comparison not only for major reactants and products, but also for reactive intermediates. It is necessary to be circumspect as far as minor intermediates are concerned (for example, with mole fractions less than about 10"" ), since there may be large uncertainties in the measurements themselves. When assessing rate parameters it is also necessary to carry out sensitivity analyses (Chapter 7) to determine the relative importance of each elementary reaction and intermediate in the mechanism. The final mechanism and rate parameters must, further, be consistent with results from studies of other combustion phenomena, such as data obtained from shock tube, explosion limit, or fast flow studies. 

There is no satisfactory chemical way of distinguishing betn een ethane and methane, both of which burn with an almost non-luminous flame this fact however is quite unimportant at this stage of the investigation. Hydrogen also burns with a non-luminous flame and w hen the open end of a test-tube full of the gas is placed in a Bunsen flame, a mild explosion with a very characteristic report takes place. 

The chief danger and main source of error in a combustion is that of moving the Bunsen forward a little too rapidly and so causing much of the substance to burn very rapidly, so that a flash-back occurs. This usually causes an explosion wave to travel back along the tube towards the purification train, some carbon dioxide and water vapour being carried with it. If these reach the packing of the purification train they will, of course, be absorbed there and the results of the estimation will necessarily be low. 

The second indication is a faint smoke-like cloudiness in the zone of the tube which is being heated by the Bunsen this is readily visible as the interior of the tube is normally quite clear and bright. This is a later stage of development of the flash-back than the rise of pressure, already mentioned, and should be counteracted by moving the Bunsen immediately to the point of the combustion tube where heating was commenced. In either case the Bunsen should then be moved slowly forwards as before. A flash-back is attended by the deposition of carbon particles, carried back by the explosion wave, on the cold walls of the tube. Care should be taken that these are completely burnt off as the Bunsen is slowly moved forward again. 

Ammoniacal Silver Nitr. te. Add 1 drop of 10% aqueous NaOH solution to about 5 ml. of silver nitrate solution in a test-tube then add dilute NHg drop by drop with shaking until only a trace of undissolved Ag O remains. A number of reductions require the presence of Ag " ions. It is often advisable, therefore, after adding the ammonia to add silver nitrate solution until a faint but permanent precipitate is obtained. The solution should always be prepared in small quantities immediately before use, and any unexpended solution thrown away afterwards. If the solution is kept for some time, it may form explosive by-products. 

An alternative method for ascertaining the end of the reaction, which does not involve the removal of the cover, is to conduct the exit gas through an empty wash bottle (to eict as a trap in case of sucking back ) and then collect a sample in a test-tube over water. If an inflammable gas (hydrogen) is absent, the reaction may be considered complete. Under no circumstances should the reaction be stopped until all the sodium has completely reacted too early arrest of the reaction may result in the product containing sodium hydride, which appears to be partially responsible for the explosive properties of the impure substance ... 

An additional useful test is to distil the acid or its sodium salt with soda lime. Heat 0.5 g. of the acid or its sodium salt with 0 2 g. of soda lime in an ignition tube to make certain that there is no explosion. Then grind together 0-5 g. of the acid with 3 g. of soda hme, place the mixture in a Pyrex test-tube and cover it with an equal bulk of soda hme. Fit a wide dehvery tube dipping into an empty test-tube. Clamp the tube near the mouth. Heat the soda lime first and then the mixture gradually to a dull-red heat. Examine the product this may consist of aromatic hydrocarbons or derivatives, e.g., phenol from sahcyUc acid, anisole from anisic acid, toluene from toluic acid, etc. 

The following alternative procedure is recommended and it possesses the advantage that the same tube may be used for many sodium fusions. Support a Pyrex test tube (150 X 12 mm.) vertically in a clamp lined with asbestos cloth or with sheet cork. Place a cube (ca. 4 mm. side = 0 04 g.) of freshly cut sodium in the tube and heat the latter imtil the sodium vapour rises 4 5 cm. in the test-tube. Drop a small amount (about 0-05 g.) of the substance, preferably portionwise, directly into the sodium vapour CAUTION there may be a slight explosion) then heat the tube to redness for about 1 minute. Allow the test tube to cool, add 3-4 ml. of methyl alcohol to decompose any unreacted sodium, then halffill the tube with distilled water and boil gently for a few minutes. Filter and use the clear, colourless filtrate for the various tests detailed below. Keep the test-tube for sodium fusions it will usually become discoloured and should be cleaned from time to time with a little scouring powder. 

Explosion-bonded metals are produced by several manufacturers in the United States, Europe, and Japan. The chemical industry is the principal consumer of explosion-bonded metals which are used in the constmction of clad reaction vessels and heat-exchanger tube sheets for corrosion-resistant service. The primary market segments for explosion-bonded metals are for corrosion-resistant pressure vessels, tube sheets for heat exchangers, electrical transition joints, and stmctural transition joints. Total world markets for explosion-clad metals are estimated to fluctuate between 30 x 10 to 60 x 10 annually. 

Some reactors are designed specifically to withstand an explosion (14). The multitube fixed-bed reactors typically have ca 2.5-cm inside-diameter tubes, and heat from the highly exothermic oxidation reaction is removed by a circulating molten salt. This salt is a eutectic mixture of sodium and potassium nitrate and nitrite. Care must be taken in reactor design and operation because fires can result if the salt comes in contact with organic materials at the reactor operating temperature (15). Reactors containing over 20,000 tubes with a 45,000-ton annual production capacity have been constmcted. 

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