Leaks


Vapor cloud explosions. Explosions which occur in the open air are vapor cloud explosions. A vapor cloud explosion is one of the most serious hazards in the process industries. Although a large toxic release may have a greater disaster potential, vapor cloud explosions tend to occur more frequently. Most vapor cloud explosions have been the result of leaks of flashing flammable liquids.  [c.258]

This eliminates the vapor space but sealing the edge can be a problem. Double seals can help and sometimes a fixed roof is also added above the floating roof to help capture any leaks from the seal. However in this case, the space between the fixed and floating roof now breathes and an inert gas purge of this space would typically be used. The inert gas would be vented to atmosphere after treatment.  [c.262]

Reaction rates often may be improved by using more extreme operating conditions. More extreme conditions may reduce inventory appreciably. However, more extreme conditions bring their own problems, as we shall discuss later. A very small reactor operating at a high temperature and pressure may be inherently safer than one operating at less extreme conditions because it contains a much lower inventory. A large reactor operating close to atmospheric temperature and pressure may be safe for different reasons. Leaks are less likely, and if they do happen, the leak will be small because of the low pressure. Also, little vapor is produced from the leaking liquid because of the low temperature. A compromise solution employing moderate pressure and temperature and medium inventory may combine the worst features of the extremes. The compromise solution may be such that the inventory is large enough for a serious explosion or serious toxic release if a leak occurs, the pressure will ensure that the leak is large, and the high temperature results in the evaporation of a large proportion of the leaking liquid.  [c.263]

Distillation. There is a large inventory of boiling liquid, sometimes under pressure, in a distillation column, both in the base and held up in the column. If a sequence of columns is involved, then, as discussed in Chap. 5, the sequence can be chosen to minimize the inventory of hazardous material. If all materials are equally hazardous, then choosing the sequence that tends to minimize the flow rate of nonkey components also will tend to minimize the inventory. Use of the dividing-wall column shown in Fig. 5.17c will reduce considerably the inventory relative to two simple columns. Dividing-wall columns are inherently safer than conventional arrangements because they lower not only the inventory but also the number of items of equipment and hence lower the potential for leaks.  [c.263]

Large quantities of toxic gases such as chlorine and ammonia and flammable gases such as propane and ethylene oxide can be stored either under pressure or at atmospheric pressure under refrigerated conditions. If there is a leak from atmospheric refrigerated storage, the quantity of hazardous material that is discharged will be less than that from a corresponding pressurized storage at atmospheric temperature. For large storage tanks, refrigeration is safer. However, this might not be the case with small-scale storage, since the refrigeration equipment provides sources for leaks. Thus, in small-scale storage, pressurization may be safer.  [c.265]

High pressure. Most process plant operates at pressures below 250 bar, but certain processes, such as high-pressure polyethylene plants, operate at pressures up to about 3000 bar. The use of high pressure greatly increases the stored energy in the plant. Although high pressures in themselves do not pose serious problems in materials of construction, the use of high temperatures, low temperatures, or corrosive chemicals together with high pressure does. With high-pressure operation the problem of leaks becomes much more serious, since this increases the mass flow rate of fluid which can leak out through a given hole. This is particularly so when the fluid is a flashing liquid.  [c.267]

Use the divided wall column shown in Fig. 5.17c to reduce the inventory relative to two simple columns, and reduce the number of items of equipment and hence lower the potential for leaks.  [c.271]

To detect surface anomalies caused by hydrocarbon accumulations often very small amounts of petroleum compounds have leaked into the overlying strata and to the surface. On land, these compounds, mostly gases, may be detectable in soil samples.  [c.24]

Tubing corrosion due to FIgS (sour corrosion) or COg (sweet corrosion) may become so severe that the tubing leaks. This would certainly require a workover. Monitoring of the  [c.338]

Number of hydrocarbon leaks  [c.1012]

Leaking fi om process flows may pose operational risks and cause environmental problems as well as economic losses. Two examples of tracer methods for testing, localising and quantifying leaks are given below.  [c.1057]

The Detector Module houses the two high sensitive radiation detectors programmed to quantify and differentiate the radiation into spectral energy counters. Information about the radiation level and energy distribution is obtained for sections of the pipeline less than one meter. The spectral information is used to distinguish the signals fi om the leaked tracer from the natural background radiation thus improving the sensitivity in identification of leaks.  [c.1060]

In the demonstration survey leaks were simulated by placing minor amounts of tracer outside the pipeline at difterent positions.  [c.1060]

The methodology and the pigging tool have proven to be capable of identifying very small leaks. In oil pipelines like the Danish carrying 1500 m /h leakages down to 1 litre per hour can be detected without injection of large quantities of tracer. Leakages can be positioned with an accuracy of less than 1 metre.  [c.1060]

The tap T2 is now turned off and the apparatus tested for leaks. If no bubbles appear at the end of the capillary X there is no leak between Y and the tap Ti of the bottle W. The best way of observing X is to shake off any bubbles at its end and then to observe the water meniscus inside the capillary. If it continues to move, there is a leak. The tap Ti is now opened and X observed again rapid cessation of flow indicates no leak up to the first tap T3 on the carbon dioxide absorption train. The process is repeated for the other taps, T4, Tg, and Tg, of the absorption tubes water may flow for a few seconds on opening as the Mariotte bottle has then been put in contact with with the whole length of the hot combustion tube up to the tap Tj of the purification train. If any leak is encountered at any stage all the taps should be closed, the faulty tap or tube adjusted, and the process repeated. The tap Tj is then opened and the oxygen stream flowed to pass through the apparatus. If necessary the level on the pressure gauge D is adjusted to 6 cm. by the micro screw-clip E, and then the side-arm Y of the Mariotte bottle lowered until there is a rate of flow of 5 ml./min. If it is found necessary to lower Y more than a few centimetres there is an obstruction in the system. This is nearly alw ays caused by one or more of the taps on the absorption tubes being not quite completely open when opening the taps it is essential to ensure that side-arm and hole in the tap are exactly in line, as the thumb-grip on the top of the tap is not always set exactly at right-angles to the tap-hole. A 5 or 10 ml. measuring cylinder should be used when adjusting the rate of flow so that the value is measured with reasonable accuracy.  [c.478]

Carrying out a combustion. The apparatus (Fig. 85, p. 469) will have been left with the bottle W connected to the beak of the combustion tube via the guard tube V and with all the taps shut the combustion tube, which is always allowed to cool down while connected to the oxygen source, will therefore be full of oxygen at slightly above atmospheric pressure, thus preventing any leaking in of carbon dioxide or water vapour from the air.  [c.477]

The tap T2 is now turned off and the apparatus tested for leaks. If no bubbles appear at the end of the capillary X there is no leak between Y and the tap T[ of the bottle W. The best way of observing X is to shake off any bubbles at its end and then to observe the water meniscus inside the capillary. If it continues to move, there is a leak. The tap Ti is now opened and X observed again rapid cessation of flow indicates no leak up to the first tap Tj on the carbon dioxide absorption train. The process is repeated for the other taps, T<, Tj, and T5, of the absorption tubes water may flow for a few seconds on opening T5 as the Mariotte bottle has then been put in contact with with the whole length of the hot combustion tube up to the tap Tj of the purification train. If any leak is encountered at any stage all the taps should be closed, the faulty tap or tube adjusted, and the process repeated. The tap T2 is then opened and the oxygen stream flowed to pass through the apparatus. If necessary the level on the pressure gauge D is adjusted to 6 cm. by the micro screw-clip E, and then the side-arm Y of the Mariotte bottle lowered until there is a rate of flow of 5 ml./min. If it is found necessary to lower Y more than a few centimetres there is an obstruction in the system. This is nearly always caused by one or more of the taps on the absorption tubes being not quite completely open when opening the taps it is essential to ensure that side-arm and hole in the tap are exactly in line, as the thumb-grip on the top of the tap is not always set exactly at right-angles to the tap-hole. A 5 or 10 ml. measuring cylinder should be used when adjusting the rate of flow so that the value is measured with reasonable accuracy.  [c.478]

The major uses of methanol are m the preparation of formaldehyde and tert butyl methyl ether (known commercially as MTBE) Formaldehyde is a starting material for various resins and plastics including the first completely synthetic plastic bakelite MTBE IS an effective gasoline additive but problems with it leaking from underground tanks and contaminating groundwater make it unsuitable for continued use Minor amounts of methanol are used as a solvent and as a convenient clean burning liquid fuel This last property makes it a candidate as a fuel for automobiles—methanol is already used to power Indianapolis class race cars  [c.624]

The differences between the various laboratories were traced to a number of factors including imperfect control of the conditions of outgassing (time, temperature, final pressure) variation in temperature of the sample during the experiment inadequate monitoring of the saturation vapour pressure purity of nitrogen (e.g. unsuspected presence of oxygen) and incidence of leaks in the apparatus. In addition, since the BET plot is never linear over the whole range of relative pressure, there is some latitude in locating the best straight line.  [c.104]

LUST. See Leaking underground storage tanks.  [c.580]

Groundwater. Spkls of refined petroleum product on land, and leaking underground storage tanks, sometimes contaminate groundwater. Bioremediation is becoming an increasingly popular treatment for such situations.  [c.29]

The bioremediation of polychlorinated biphenyls in soils in receiving significant attention because these compounds are quite widely distributed in the environment, either from leaking electrical transformers or sometimes because they were appHed as part of road maintenance. In the latter case, the contamination usually includes petroleum hydrocarbons, and unfortunately it seems that the two contaminants inhibit the degradation of each other. Nevertheless, cultures are being found that can degrade both polychlorinated biphenyls and petroleum hydrocarbons. There is also interest in the role of rhizosphere organisms in polychlorinated biphenyl degradation, particularly since some plants exude phenoHc compounds into the rhizosphere that can stimulate the aerobic degradation of the less chlorinated biphenyls.  [c.34]

In situations where sufficient thermal radiation is available the spectral band can be narrowed (by filters or spectrometer) with only a proportional reduction in sensitivity. When the spectral band is narrowed to a particular absorption band of a given chemical substance the spatial distribution and temporal variation of that substance maybe measured as was done in the visible by astronomers (scanning sHt spectrographs) for many years. Infrared focal plane array technology is making possible spectrographic imaging in the infrared portion of the electromagnetic spectmm which is rich in molecular absorption lines. This will have a major impact on industrial processing where control of the chemistry is essential for cost reduction and safety. The potential appHcations are detection and source location of toxic gases, monitoring chemical manufacturing processes on a real-time basis, remote temperature profile sensing, automobile exhaust gas monitoring and measuring the location and degree of chemical leaks in production or storage. Spectral thermography will help detect and control toxic atmospheric gases such as CO, N O, SO, NH and ozone. A thermographic sensor with an integral gas sampling tube is a spot sensor and that with a remote heat source or retro-mirrors performs remote sensing.  [c.290]

Industrial use of thermal imaging typically is the detection of thermal anomaUes (13,14) such as leaking pipes and valves, overheating boilers, transformers and power lines, and friction generated heat in bearings. A thermal image of a transformer station is shown in Figure 7. These are simple heat detection appHcations but the imaging process quickly locates the problem in the three-dimensional industrial environment. The in camera is scanned like a TV camera and the output signal is digitized for evaluation by a programmed computer than compares the output of each frame with a caUbrated reference frame. An alarm declares when a thermal anomaly is detected. Defects in materials (15) and circuit boards (16) can be detected by the associated discontinuities in thermal conduction.  [c.294]

The advantages of a hydraulic scale are immunity from electrical transients and lightning damage, that vibration can be controlled by damping, and that downward travel of the platform or weighing container is relatively small. The disadvantages include the fact that additional equipment, either mechanical or electrical, is requited to sum the individual cell outputs in multiple-cell appHcations, or for control or data acquisition purposes the fact that the speed of operation is dependent on temperature, ie, as a result of variations in the viscosity of the hydraulic fluid and the fact that there is a danger of contamination from leaking hydraulic fluid.  [c.325]

Langmuir [7] in 1917 gave a great impetus to the study of monomolecular films by developing the technique used by Pockels. He confined the film with a rigid but adjustable barrier on one side and with a floating one on the other. The film was prevented from leaking past the ends of the floating barrier by means of small aiijets. The actual force on the barrier was then measured directly to give IT, the film pressure (see Section III-7). As had been observed by Miss Pockels, he found that one could sweep a film off the surface quite cleanly simply by moving the sliding barrier, always keeping it in contact with the surface. As it was moved along, a fresh surface of clean water would form behind it. The floating barrier was connected to a knife-edge suspension by means of which the force on the barrier could be determined. The barriers were constructed of paper coated with paraffin so as not to be wet by the water.  [c.102]

The light leaking out of the cavity will decay exponentially, witli a time constant that reflects the round-trip losses. Wlien an absorbing sample is placed in the cavity, there are additional losses and the exponential tune constant will become shorter. More highly absorbing samples will affect tlie time constant to a larger extent, and the absolute absorption is detennined. The experiment is shown schematically in figure Bl.2.9. One of the most important attributes of CRLAS is that it is relatively insensitive to laser pulse intensity fluctuations since the ringdown tune constant, not the transmitted intensity, is measured.  [c.1170]

In general it is difficult to construct a calorimeter that is truly adiabatic so there will be unavoidable heat leaks q. It is also possible that non-deliberate work is done on the calorimeter such as that resulting from a change in volume against a non-zero external pressure / Pk i dk>, often called /iFwork. Additional work w  [c.1899]

Carrying out a combustion. The apparatus (Fig. 85, p. 469) will have been left with the bottle W connected to the beak of the combustion tube via the guard tube V and with all the taps shut, the combustion tube, which is dways allowed to cool down while connected to the oxygen source, will therefore be full of oxygen at slightly above atmospheric pressure, thus preventing any leaking in of carbon dioxide or water vapour from the air.  [c.477]

To carry out a distillation, the liquid is ix>med into the Claisen flask so that it is about one-half full, and the apparatus is completely assembled as in Figs. 77, 19, 1-2. The barometric pressure is read. The flask is heated either by means of an air bath (Fig. 77, 5, 3) or by means of a water or oil bath in the latter case the bulb of the flask is immersed at least two-thirds into the bath, which should contain a thermometer. The water pump is then turned on to its maximum capacity and the screw clip D almost fuUy closed.t The latter is then adjusted so that a fine stream of air bubbles passes through the liquid when the mercury in the manometer ceases to rise, the reading (in mm.) is taken on F and this value is subtracted from the atmospheric pressure in order to obtain the pressure within the system. If the pressure thus obtained does not differ by more than 10 mm. from that expected from the temperature of the tap water, the set-up may be regarded as satisfactory. If the pressure is unsatisfactory, the apparatus must be carefully tested for leaks and these eliminated before the distillation can be commenced special attention should be paid to ensure that all the stoppers are firmly in position and all the rubber pressure tubing fits tightly over the glass tubing. The coohiig water for the receiver is first turned on, and, when the mercury level on the gauge is more or less steady, heating is commenced. (For high boihng point liquids, it is advantageous to wTap linen cloth or, better, asbestos cloth or string round the neck of the flask below the outlet tube.) If an air bath is employed, the temperature is slowly raised until the hquid commences to distil, and the heating is  [c.105]

The underlying principle is that the gas in the system whose pressure is to be controlled must overcome the pressure of a column of liquid before it can be pumped out. When the pump is first started the bulk of the air in the system is removed through the open stopcock. When the pressure, as measured on a mercury manometer, has almost reached the desired value, the stopcock is closed thus forcing the remaining gas to be pumped through the head of liquid in the manostat. The end of the gas inlet tube is constricted (say, to 1-1-5 mm.) so that when the system has reached equilibrium, the constant leaks therein (including the distillation capillary) cause a steady stream of bubbles instead of the more intermittent larger bubbles that result If a capillary is absent. Before admitting air when the distillation has been completed, the stopcock is opened in order to avoid violent splashing of  [c.114]

Place 01 g. of the catalyst in the hydrogenation vessel and then introduce a solution of 5 9 g. of pure maleic acid (Section 111,143) in 75 ml. of absolute alcohol. Make sure that the catalyst is completely covered by the solution, since an explosion may occur when hydrogen is admitted if traces of the platinum oxide stick to the walls of the bottle. Lubricate the stopper with an inert grease (compare Section 11,59) and insert it into the vessel fix it securely in position by means of two short lengths of rubber tubing passing over the top of the stopper and held tightly against the neck of the bottle by means of copper wire ligatures. Connect the hydrogenation vessel H to the supply of hydrogen in the cylinder A by means of a length of rubber pressure tubing and firmly clamp the bottle in the shaking machine. Displace the air from the connecting tubes and from the bottle by closing stopcock 2, opening stopcocks 1, 3 and 4, and passing about 1500 ml. of hydrogen slowly from the reservoir alternately close and open tap 4 from time to time in order to assist the displacement and also to detect any leaks in the ground glass joint. Finally, close taps 3 and 4, and recharge reservoir A so that it contains about 2 litres of hydrogen. Open taps 1 and 3. Equalise the water levels in A and B, open tap 4 momentarily and record the reading on A raise R to its original position (as in Fig. 111,150, 1), Set the  [c.473]

All of the pieces pictured here are not going to fit perfectiy into each other and that s going to cause all sorts of leaks. The answer is teflon tape. Strike loves teflon tape This inexpensive product is found in the plumbing department of any hardware store and is the duct tape of the next century. Teflon tape is chemically and thermally indestructible. This stuff is wrapped around any piece of pipe or joint, said part then jammed into its appropriate receptacle and the tape will mold to form a perfect fit. Hell, it can mummify a whoie joint compiex to make it absolutely impregnable.  [c.20]

An interesting thing happens when trapped methane leaks from sites under the deep ocean floor If the pressure is high enough (50 atm) and the water cold enough (4°C) the methane doesnt simply bub ble to the surface Individual methane molecules be come trapped inside clusters of 6-18 water molecules forming methane clathrates or methane hydrates Aggregates of these clathrates stay at the bottom of the ocean in what looks like a lump of dirty ice Ice that burns Far from being mere curiosities methane clathrates are potential sources of energy on a scale greater than that of all known oil reserves combined At present it is not economically practical to extract the methane however  [c.66]

At one time thiols were named mercaptans Thus CH3CH2SH was called ethyl mercaptan according to this system This nomenclature was abandoned beginning with the 1965 revision of the lUPAC rules but is still sometimes encountered When one encounters a thiol for the first time especially a low molecular weight thiol its most obvious property is its foul odor Ethanethiol is added to natural gas so that leaks can be detected without special equipment—your nose is so sensitive that it can detect less than one part of ethanethiol m 10 000 000 000 parts of arr The odor of thiols weakens  [c.648]

The gas pressure in the first hexapole section is influenced by gas leaking in from the inlet system and, at about 10" mbar, is higher than desirable if excessive ion/neutral collisions are to be prevented. Therefore, the first hexapole is separated from the second hexapole section by a small orifice, which allows ions to pass through.  [c.403]

Early laser Stark spectra were obtained with the absorption cell outside the laser cavity but there are advantages in placing it inside the cavity, an arrangement shown in Figure 9.23. The laser cavity is bounded by the mirror M and the grating G, used for selecting wavelengths in a multiple-line laser such as CO2 or CO. The sample compartment is divided from fhe laser compartmenf by a window W (all fhe windows are af Brewsfer s angle - see Equation 9.14). The Sfark electrodes S are only a few millimetres apart in order to produce a large field between them, of the order of 50 kV cm. Some of the laser radiation leaks out to a detector D.  [c.368]

Cmde oil has been part of the biosphere for millennia, leaking from oil seeps on land and in the sea. Cmde oils are very complex mixtures, primarily of hydrocarbons although some components do have heteroatoms such as nitrogen (eg, carbazole) or sulfur (eg, dibenzothiophene). Chemically, the principal components of cmde oils and refined products can be classified as aUphatics, aromatics, naphthenics, and asphaltic molecules. Representative examples are shown in Figure 1. The ratios of these different classes varies in different oils, but a typical cmde oil might contain the four classes in a ratio of approximately 30 30 30 10. Most cmde oils contain hydrocarbons ranging in size from methane to molecules with hundreds of carbons, although the Lightest molecules are usually absent in oils that have been partially biodegraded in their reservoir. When cmde oils reach the surface environment the lighter molecules evaporate, and are either destroyed by atmospheric photooxidation or are washed out of the atmosphere in rain, and are biodegraded. Some molecules, such as the smaller aromatics (benzene, toluene, etc) have significant solubiUties, and can be washed out of floating sHcks, whether these are at sea, or on terrestrial water tables. Fortunately the majority of molecules in cmde oils, and refined products made from them, are biodegradable, at least under aerobic conditions.  [c.26]

Soil. Hydrocarbon contamination of soils mns the gamut from cmde oils at production well and pipeline spills, to the full slate of refined products at refineries, distribution centers, service stations and accident sites. Significant hydrocarbon contamination is also often found at manufactured gas plants, now mainly abandoned, wood treatment faciUties, railroad rights of way and terminals, and various military bases. Sometimes the contamination is the result of leaking underground storage tanks and pipelines, leading to subsurface contamination, but surface spills also occur. Physical removal of gross contamination is an obvious first step at all locations, and bioremediation is an appealing option for remediating residual contamination ia many of these sites.  [c.30]

Technologies to prevent recontamination during the deHvery process have been an intense area of development. Work in the 1970s focused mainly on preventing contamination of high purity inert gases such as N2 and Ar by atmospheric leaks and the release of atmospheric impurities which had been adsorbed on the inner surfaces of deHvery systems during assembly. More recently, work has focused on preventing contamination of corrosive gases, such as HCl and HBr, with contaminants that contribute metallic impurities such as Fe and Ti to the electronic materials.  [c.89]


See pages that mention the term Leaks : [c.1462]    [c.2470]    [c.105]    [c.63]    [c.9]    [c.559]    [c.766]    [c.1044]    [c.90]    [c.90]    [c.91]   
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What went wrong  -> Leaks


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