Download or read book Promoted Ignition Combustion Tests of Brazed Aluminum Heat Exchanger Samples in Cold Supercritical Oxygen written by James White and published by . This book was released on 2016 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: A common practice in the industrial gas industry is to produce product oxygen by boiling pressurized liquid oxygen in a heat exchanger. Multistream brazed aluminum heat exchangers (BAHX) typically are used as oxygen product vaporizers. This method inherently exposes liquid and gaseous oxygen to aluminum material. Customer demands continue to increase the product oxygen pressure requirements, and it is recognized that higher pressures could increase the severity of an aluminum/oxygen combustion event. A series of experimental programs were conducted from 1993 to 1995 to evaluate the safe use of BAHX for boiling oxygen at elevated pressures to 6,996 kPa. The present experimental study is a companion test program that was conducted from 2010 to 2012 to evaluate BAHX promoted combustion response in cold supercritical oxygen to 15,602 kPa. Promoted combustion experiments were conducted with miniature headered BAHX samples. Two types of samples were tested. The first were approximately 3.3 kg, having a thinner parting sheet thickness, and the second approximately 3.9 kg, having thicker parting sheets. The oxygen passages contained commercial purity cold supercritical oxygen having a pressure ranging from 10,197 to 15,603 kPa and the adjacent passages contained cold supercritical air ("inert" fluid) at pressures ranging from 10,440 to 15,170 kPa. Tests were conducted with the air passage pressure both higher and lower than the oxygen passage pressure. Nichrome wire was used to ignite a hydrocarbon promoter located within an oxygen passage, simulating a promoted ignition-combustion event. The experiments provided insights into the combustion mitigation behavior of BAHX used for producing high-pressure product oxygen via pumped liquid oxygen (LOX) gasification. Data are applicable in supporting the safe use of BAHX for high-pressure oxygen service.
Download or read book Promoted Ignition Combustion Tests of Brazed Aluminum Heat Exchanger Samples in Gaseous and Liquid Oxygen Environments written by R. Zawierucha and published by . This book was released on 2000 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most air separation plants employ compressors to increase oxygen pressure for customer usage. An alternative approach is to extract liquid oxygen from the separation column, which is pumped to higher pressure and then boiled in a heat exchanger to directly provide an elevated pressure gaseous oxygen product. Brazed aluminum heat exchangers (BAHX) are normally utilized as the product oxygen vaporizers.
Download or read book Promoted Ignition Combustion Behavior of Tubular Aluminum Samples in Liquid and Gaseous Oxygen Environments written by R. Zawierucha and published by . This book was released on 2003 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Past literature has reported on the occurrence of violent energy releases (VER) involving either high surface area aluminum structured packing or brazed aluminum heat exchanger (BAHX) samples subjected to promoted ignition-combustion testing in liquid oxygen (LOX) environments. In each of these situations, both the aluminum packing samples and the BAHX specimens contained relatively thin sections of aluminum. The aluminum thickness ranged from 0.2 to 0.25 mm for the aluminum packing and the fin portion of "thin fin" BAHXs. Other "thick fin" BAHXs tested had nominal fin thicknesses ranging from 0.41 mm to 0.46 mm. Similar flammability data have not been reported for thick wall (4.1 mm), 3003 tubular aluminum heat exchanger material which may be used in LOX applications. The impetus for this program was to study the promoted-ignition combustion behavior of thick wall, tubular aluminum samples in various LOX environments using both a localized hydrocarbon promoter and uniformly dispersed hydrocarbon film. Tests were also conducted in various gaseous oxygen (GOX) environments using uniformly dispersed hydrocarbon films.
Download or read book Pressure Dependence of Aluminum Ignition in Gaseous Oxygen and Possible Ignition Mechanisms in Brazed Aluminum Heat Exchangers written by Etienne Werlen and published by . This book was released on 2012 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ignition of aluminum foils in gaseous oxygen was experimentally tested using a diode laser as the energy source, which provided a well-controlled, accurate, and reproducible method of ignition. The tests were conducted under different conditions in terms of oxygen pressure, oxygen purity, aluminum thickness, and gas velocity. The aluminum foils tested were between 0.2 mm and 0.45 mm thick, a range typical of fins contained in brazed aluminum heat exchangers (BAHXs) used in air separation units (ASUs). The experimental apparatus was composed of a pressure vessel in which a single aluminum test sample was placed. The vessel contained an optical window that allowed a short laser pulse of known power to be applied to the aluminum sample. The energy dose was systematically varied in order to identify the threshold ignition energy, defined as the point at which the probability of aluminum combustion with propagation beyond the laser spot was 50 %. The experimental results show that O2 pressure has no significant effect on the ignition energy of aluminum over the pressure range tested (10 bar to 120 bar). This conclusion holds for both standard commercial grade purity O2 (99.8 %) and high purity O2 (99.99 %), as well as for gas velocities higher than typically encountered in ASU BAHXs. Heat conduction calculations indicate that aluminum ignition occurs when the laser spot temperature reaches the melting point of the passivating oxide layer (about 2200 K to 2300 K). The heat conduction model accurately explains the dependence of the ignition energy on the aluminum sample thickness. These test results have been used in assessing the risk of ignition of BAHXs used in high pressure oxygen service in ASUs.
Download or read book Flammability Tests of Miniature Brazed Aluminum Heat Exchangers in Liquid Oxygen written by JF. Million and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most air separation plants currently in use employ compressors to increase oxygen pressure for customer usage. An alternative approach is to extract liquid oxygen from the separation column which is pumped to higher pressure and then boiled in a heat exchanger to directly provide an elevated pressure gaseous oxygen product. Brazed aluminum heat exchangers (BAHX) are normally utilized as the product oxygen vaporizers. The process results in substantial contact between high pressure liquid oxygen and aluminum material. The increased use of BAHXs to produce pressurized oxygen as an alternative to the use of oxygen compressors led to a series of experimental programs pertinent to the safe use of BAHXs for boiling oxygen at elevated pressures.
Download or read book Ignition of Contaminated Aluminum by Impact in Liquid Oxygen Influence of Oxygen Purity written by Etienne Werlen and published by . This book was released on 2009 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Impact tests in liquid oxygen and oxygen enriched liquids have been conducted on aluminum foils (0.2 mm thick) used for heat exchangers of air separation units (ASUs). Some adaptations to the ASTM Standard D2512, "Standard Test Method for Compatibility of Materials with Liquid Oxygen," have been done to ensure the good control of oxygen content in the cryogenic liquid and to get reproducible results in aluminum ignition with hydrocarbon coating. Modified striker pins with a cavity on the contact surface have been used. The vertical guiding and the centering of the striker pins have been ensured by using two machined guides. Test samples were three layers of aluminum foil, two corrugated and one flat, contaminated by various quantities of hexadecane. The criteria for the identification of aluminum ignition (positive tests) have been validated by performing Scanning electron microscope surface analysis on residuals of a few impact tests performed in copper cups. Criteria have also been defined to check that hexadecane combustion took place in negative tests. A sufficient number of tests have been performed to plot the probability of ignition of the aluminum samples as a function of the average thickness of hexadecane coating and as a function of the oxygen content in the cryogenic liquid varying from 50 % to above 99.95 %. The remaining part in the cryogenic liquid was nitrogen and 2.3 % argon except for one series of tests where the influence of the absence of argon could be identified. The results of these tests can be used to assess the risk of ignition of some aluminum exchangers or structures used in ASU.
Download or read book Promoted Ignition Combustion Tests with Structured Aluminum Packings in Gaseous Oxygen with Argon Or Nitrogen Dilution at 0 1 and 0 6 MPa written by M. Meilinger and published by . This book was released on 2003 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-surface-area aluminum structured packings are finding a wide use in the cryogenic distillation of air. An experimental program was performed to determine the oxygen compatibility of commercial packings. In particular, the influence of pressure increase up to 0.6 MPa (6 bar absolute) and the effect of the replacement of nitrogen by argon as O2-diluting gas were investigated. Additionally, the impact of reducing the sheet thickness from 0.2 mm to 0.1 mm was tested.
Download or read book Surface Ignition of Aluminum in Oxygen written by B. Newton and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published reports of burning aluminum in oxygen using ASTM G 124-type testing demonstrated that aluminum alloys are difficult to ignite but once ignited are extremely flammable in terms of regression rate and energy release. The ignition resistance of aluminum is associated with its tenacious and protective oxide, which allows aluminum to safely contain high-pressure oxygen in certain applications. The ignitability of aluminum varies between alloys and surface treatments so a test method was developed to evaluate the ignitability of various aluminum surfaces. The test method uses a promoted ignition chamber consistent with ASTM G 124 testing; however, the test sample is configured in the shape of a coupon. Instead of promoting the sample with an electrically heated wire, a controlled electrical arc is generated by drawing an electrode away from the center of the coupon while passing current through the sample. The level of energy applied to the surface of the coupon is semi-quantifiable and kept constant between tests. Based on this semi-quantifiable amount of energy, an ignition pressure is established and the influence of alloy composition and surface treatments on aluminum is evaluated.
Download or read book Reaction of Molten Burning Aluminum with Liquid Oxygen written by HM. Barthélémy and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminum packings and trays are used in the cryogenic distillation of air. During the sixth International Symposium on Flammability and Sensitivity of Materials in Oxygen Enriched Atmospheres, we presented test results under simulated operating conditions of aluminum packings in oxygen atmosphere. Flammability tests were also performed on aluminum tray samples and heat exchangers. During these tests, a violent energy release (VER) was observed when aluminum samples were ignited and a LOX pool was present. It was established that this phenomenon was not relevant for the operating conditions of cryogenic air separation plants, but the conditions necessary to obtain/explain this VER were not clear. The VER's were attributed to molten/burning aluminum coming into contact with LOX. In this paper we have analyzed, from the tests already performed, the conditions/parameters necessary for this phenomenon to occur. Further tests were also performed involving aluminum rods, in order to get a better understanding of this phenomenon. The results show that the necessary conditions to obtain a pressure wave: ? do not depend on the geometry of the sample (packings, trays, heat exchangers, rods) ? are the simultaneous presence of a vaporizable liquid (LOX) and a very hot molten material (liquid aluminum T > 1900 K or liquid alumina) ? are the rapid contact and mixing of these two liquids so as to get a quick vaporization of LOX.
Download or read book Ignition of Metals at High Temperatures in Oxygen written by MJ. Slockers and published by . This book was released on 2006 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Material flammability is thought to increase with increasing oxygen concentration, increasing pressure, and increasing temperature. Interest in the effects of increasing pressure and increasing sample temperature on the flammability of metals led to an industry-sponsored program for heated promoted combustion testing of metals. In this paper, the results of heated promoted combustion tests from the industry-sponsored 98-1 program are reported. Thirteen materials were tested as heated 3.2-mm (1/8-in.) diameter rods in an enriched oxygen, elevated pressure environment. Tests were performed in 100 % oxygen, and the temperature of the sample rods varied between 260 and 1093°C with test pressures ranging from 0.2 to 2.8 MPa. The test materials were 316 stainless steel, Incoloy® 800 HT, Hastelloy® C-276, Hastelloy C-22, Inconel® Filler Metal 601, Inconel Filler Metal 617, Haynes® 230, Haynes 214, Hastelloy X, 310 stainless steel, alonized Haynes 230, 304 stainless steel, and alonlzed Incoloy 800 HT.
Download or read book Flame Spreading and Violent Energy Release VER Processes of Aluminum Tubing in Liquid and Gaseous Oxygen Environments written by JH. Sturges and published by . This book was released on 2000 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is motivated by the need for a fundamental understanding of the unintentional combustion of aluminum heat exchange equipment used in liquid oxygen (LOX) service; in which combustion can be quite energetic and cause severe damage. The promoted ignition, flame spreading, and combustion phenomena of aluminum tubing filled with LOX, surrounded by a shell of gaseous oxygen (GOX), were systematically observed and recorded. Parameters studied include the tube- and shell-side pressures, GOX and LOX flow rates, and GOX quality (the mass fraction of GOX in the two-phase flow inside the tube sample). Results from high-speed movie films indicate that under certain operating conditions, a transition from a "normal" (much slower) burning mode to an extremely rapid and violent burning mode occurs. This transition was shown to occur in some cases after a period of delay and in other cases immediately after the onset of ignition. The "Violent Energy Release," or VER burning mode, is characterized by an extremely high flame spreading rate (1-2 orders of magnitude higher than the flame propagation rate in a purely GOX environment), a high luminosity flame-zone, and a very rapid rate of heat release. Within the range of initial conditions tested, the major parameters that tend to enhance the degree of violence of aluminum combustion in a LOX/GOX environment include increasing initial pressure and decreasing GOX quality (higher LOX fraction). A burning regime map showing the threshold boundaries between conditions of no self-sustained flame propagation, "normal" burning, and VER burning mode is presented. It was found that the threshold boundaries between the different regimes of burning are essentially determined by the tube-side conditions. In addition a detailed insight into the controlling mechanisms of the VER reaction has been obtained, and a physical description of the transition mechanism is presented.
Download or read book Promoted Metals Combustion at Ambient and Elevated Temperatures written by CD. Engel and published by . This book was released on 2006 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Promoted combustion testing of materials, Test 17 of National Aeronautics and Space Administration Standard 6001 (NASA-STD-6001), has been used to assess metal propensity to burn in oxygen-rich environments. An igniter at the bottom end of a rod promotes ignition, and if combustion is sustained, the burning progresses from the bottom to the top of the rod. The physical mechanisms are similar to those of the upward flame propagation test, Test 1 of NASA-STD-6001. The differences are in the normal environmental range of pressures, oxygen content, and sample geometry. Upward flammability testing of organic materials can exhibit a significant transitional region between no burning and complete quasi-steady burning. In this transitional region, the burn process exhibits a probabilistic nature. This transitional region has been identified for metals using the promoted combustion testing method at ambient initial temperatures. The work herein is focused on examining the transitional region and the quasi-steady burning region both at conventional ambient testing conditions and at elevated temperatures.
Download or read book Tests of Combustion of Aluminum Packing and Trayed Columns written by J-Y Lehman and published by . This book was released on 2000 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The flammability of structured packing made of thin aluminum sheet (0.2 mm) for use in oxygen service has been investigated by several companies and the results have been published since the first paper was given by Dunbobbin et al. [1]. All these previous tests involved small samples of about 100 g. The propagation on such small samples is quite difficult to analyze especially with LOX flowing down, as in actual operating conditions. The results of these tests have been published in STP 1197 [2]. Three sets of tests have been performed on larger samples to closely reproduce the operating conditions of cryogenic columns. The first set involved larger packing samples (650 g) above a LOX pool, heated to create a gas flow. The second set involved seven complete columns, 30 cm diameter x 2 m high, containing packing with LOX flowing down. The ignition pack was similar to the first set of samples. The third set involved twelve complete columns, 30 cm diameter x 2 m high, with 20 aluminum trays, in normal working conditions. The ignition cell failed in six tests so only six tests were significant. Results of this investigation performed on large samples were used when preparing the CGA pamphlet G-4.8 published in 1993 [3], which concluded that aluminum structured packing in ASUs introduces no additional risk, compared with aluminum trays.
Download or read book Spark Ignition of Aluminum Powder in Mixtures of Oxygen Nitrogen and Carbon Dioxide A New Testing Method Heat and Mass Transfer in Fires and Combustion Systems ASME Heat Transfer Division HTD V 148 Pg 97 104 written by Se-Won Kim and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prudent Practices in the Laboratory written by National Research Council and published by National Academies Press. This book was released on 2011-03-25 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prudent Practices in the Laboratory-the book that has served for decades as the standard for chemical laboratory safety practice-now features updates and new topics. This revised edition has an expanded chapter on chemical management and delves into new areas, such as nanotechnology, laboratory security, and emergency planning. Developed by experts from academia and industry, with specialties in such areas as chemical sciences, pollution prevention, and laboratory safety, Prudent Practices in the Laboratory provides guidance on planning procedures for the handling, storage, and disposal of chemicals. The book offers prudent practices designed to promote safety and includes practical information on assessing hazards, managing chemicals, disposing of wastes, and more. Prudent Practices in the Laboratory will continue to serve as the leading source of chemical safety guidelines for people working with laboratory chemicals: research chemists, technicians, safety officers, educators, and students.
Download or read book Rules of Thumb for Mechanical Engineers written by J. Edward Pope and published by Gulf Professional Publishing. This book was released on 1997 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluids -- Heat transfer -- Thermodynamics -- Mechanical seals -- Pumps and compressors -- Drivers -- Gears -- Bearings -- Piping and pressure vessels -- Tribology -- Vibration -- Materials -- Stress and strain -- Fatigue -- Instrumentation -- Engineering economics.
Download or read book Modern Engineering for Design of Liquid Propellant Rocket Engines written by Dieter K. Huzel and published by AIAA. This book was released on 1992 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
