Vent Line Research Articles

Hydrodynamics of a bubble formed at vent pipe exit

In this paper, the hydrodynamics of a bubble formed during transient injection of air through a tube submerged in a pool of water has been studied. The experiments were performed by injecting air through vertical tubes varying in diameter from 0.9 to 9.5 cm and located in the middle of a 45 cm dia. and 120 cm high plexiglas chamber. The plexiglas chamber was partly filled with water and was open at the top to the outside. Data for bubble growth and vent line pressure histories are obtained under different upstream pressure conditions. Effect of presence of an orifice in the vent line on bubble growth has also been investigated. A theoretical model describing the bubble growth at the exit of a vent pipe submerged in a pool of water is developed. Predictions of bubble radius, line static pressure and uplift on the bottom of the test chamber have been made and are found to compare well with the data. Insertion of an orifice in the pipe line between the solenoid valve and the vent exit has been found to inhibit the bubble expansion as well as alter the bubble oscillation characteristics.

Heat conduction through narrow channels and phase separation of He II at zero gravity

We explain the heat flow properties of a system which works as a phase separator for superfluid helium at zero gravity. Differently from most previous work the flow of He II in a narrow slit between a helium bath and a vapour space (instead of a second He bath) is studied. Due to the Fountain effect most of the He II stays contained in the bath, and a small amount is evaporated to carry away the heat transported through the slit. The role of evaporation kinetics is discussed and its contribution, raising the heat flow resistance, is calculated. At higher heat flow there is a sharp transition to a different flow state, which we identify with the Gorter-Mellink regime where the supercomponent flows dissipatively and liquid enters into the vent line so that an additional heat exchanger is necessary for its evaporation. In this regime the mass and heat flow are still controlled by the applied pressure gradients or-important for practical use:-by varying the length of the slit.

7] Sequence determinations of proteins and peptides at the nanomole and subnanomole level with a modified spinning cup sequenator

This chapter presents the sequence determinations of proteins and peptides at the nanomole and subnanomole level with a modified spinning cup sequenator. The chapter describes the improvements and gives practical criteria that critically assess the instrument performance. The modifications described is performed on a Beckman 890C sequenator but in principle can be applied to other instruments by allowing for changes from one model to another. The components that should be removed from the sequenator are (a) entire low-vacuum system including all lines, manifolds, and connections, (b) high-vacuum line and valve, (c) reagent, solvent, and waste diaphragm valves , (d) three-way valves and manifold that operates diaphragm valves, and (e) reagents and solvents and their connections except for vent and pressurized lines. The replacement components that follow are described by systems and require machine and glass shop fabrication work. The chemistry and operational description of an automated sequencer are discussed. One of the applications of the instrument described is the sequence determination of human leukocyte interferon, which is currently available in the nanomole range. Representative results from these studies are discussed. An important aspect of the sequencing strategy in the low nanomole to subnanomole range is the analysis of the PTH amino acids by reverse phase HPLC. These chromatograms illustrate the low backgrounds and the resulting high sensitivity, which can be reproducibly obtained with the modified sequenator.

Einfluß thermodynamischer und fluiddynamischer Vorgänge auf die Notentspannung chemischer Reaktoren

AbstractInfluence of thermodynamic and fluid dynamic mechanisms upon the emergency pressure relief of chemical reactors. The cross‐sectional areas of pressure relief devices for storage tanks and reactor vessels containing liquids under vapour pressure, which might undergo dangerous heating up, have so far been estimated on the basis of physically questionable procedures. This report analyses the pressure relief process using several extreme assumptions with regard to momentum and heat transfer in two phase flow. A conservative method of estimation is found under the assumptions of homogeneous flow and vapour‐liquid equilibrium. Using this procedure, a parametric study of the pressure relief process for a runaway polymerisation reaction has been carried out. Finally, recommendations are given concerning design of the vent line and control of the atmospheric dispersion of the relief stream via the jet exit momentum.

Ultrathin silicone/polycarbonate membranes for gas separation processes

Uniform, defect-free silicone/polycarbonate membranes as thin as 0.015 μ have been formed by spreading solutions of the copolymer on water surfaces. The membranes were readily applied to support materials. Composite membranes formed from several laminations of ultrathin membrane on a support were readily handleable and may provide the basis for practical gas separation processes. Two such processes are (1) the production of 30% oxygen-enriched air, which would require less energy than blending air with oxygen from a modern low-temperature air separation plant, and (2) the on-board generation of nitrogen-enriched air for inerting aircraft fuel tank vapor spaces and vent line.

Water-Lift and Disposal Operations in Low-Pressure Shallow Gas Wells

Abstract Salt-water removal and disposal from shallow gas wells in the Hugoton and Greenwood gas fields have become an increasingly serious problem. Panhandle Eastern Pipe Line Co. initiated a program to determine the optimum methods for removing and disposing of the salt water. Field test results on gas-lift valves, pumping units, pneumatic pumping units and a differential pressure controller indicated that the pumping unit is the most efficient and economical method for removing the water. Different methods of water disposal have been tried, such as evaporative salt-water ponds lined with vinyl plastic, reinforced concrete or tetra-sodium pyrophosphate for wells producing up to 300 bbl/month. For wells which produce more than this, slim-hole disposal wells are used. Economics of the various systems as well as the efficiency, are discussed. Introduction For the past several years operators have been confronted with ever increasing problems of salt-water removal and disposal from shallow gas wells located in southwestern Kansas, and in the Oklahoma and Texas Panhandles. These low-pressure, shallow gas wells are principally located in the Hugoton and Greenwood gas fields. Several methods of salt-water removal have been investigated through field installations and their results evaluated. Great strides have been made in recent years, and periodically new water-lift methods are recommended and investigated. So far, the pumping unit has proved the most efficient as well as an economical method of removing large quantities of salt water. As more and more water is produced the problem of disposing of the water at the surface becomes more apparent. Panhandle Eastern Pipe Line Co. has several methods of disposal in service at the present time. The evaporative salt-water pond which can be lined with vinyl plastic, reinforced concrete, or chemically treated with tetra-sodium pyrophosphate is satisfactory in this area for wells producing up to 300 bbl water/month. The salt water from wells producing in excess of this quantity is usually disposed of in a slim-hole disposal well. Field Test Results As the reservoir pressure declines, water in the formation encroaches into and near the wellbore. If this water is not removed the gas production will decline to the point where the well "logs off", and has to be blown frequently and for long periods of time to remove the water. This waste of gas is expensive, but new techniques and tools will enable us to eventually prevent this waste. Some four years ago the company began an intense study of all water-lift methods in use at that time. The principal purpose of the study was to determine the efficiency of existing water-lift methods and to investigate all conceivable means of improving the water-lift ratio, which is expressed as the number of cubic feet of gas required to lift 1 bbl of water. A test-separator unit was designed to test problem wells, most of which were equipped with gas-lift installations operated by time-cycle intermitters. The test-separator is connected to the vent line running from the tubing to the disposal pit. When the intermitter opens the tubing at a designated time, the lift gas and water are directed through the test unit where they are separated. The water is measured into a test tank and the gas volume is measured by an orifice well tester and recorded on a 24-hour chart. All wells are tested for a period of from 24 to 72 hours so an accurate and representative water-lift ratio can be determined. After the initial water-lift ratio is determined, the time cycle is changed and a new water-lift-ratio test is run. Several tests are conducted on each well to determine the optimum cycle which results in the highest water-lift efficiency, i.e., the lowest volume of gas required to lift each barrel of water. Currently two test-separators are operating full time on the testing program. Gas technicians are placed in charge of these units and instructed to test all problem wells that are producing substantial quantities of salt water. Monthly reports of hard-to-produce wells are reviewed and each well appearing on this report investigated. Those wells with a water-production problem are scheduled for water-lift-ratio tests. JPT P. 619ˆ

Topic of the Month—Elimination of a Tank Vent Line Corrosion Problem Through the Use of Aluminum Pipe and Fittings

Topic of the Month—Elimination of a Tank Vent Line Corrosion Problem Through the Use of Aluminum Pipe and Fittings

The Productivity Index

Much has been said and written on the shortcomings of the open-flow andrestricted potentials of oil wells to determine their relative ability toproduce. The oil industry in general is agreed that the open-flow potential inparticular is grossly inequitable, wasteful and expensive, but that potentialis still used in many pools. This is partly because no thoroughly satisfactorysubstitute has been found and partly because operators are reluctant to adoptother methods that have been suggested; or, as Hamlet would say, we wouldrather "bear those ills we have than fly to others we know not of. In a great many pools the use of tubing potentials has been substituted foropen-flow potentials, but open-flow potentials through casing are still beingused in many pools, particularly in Oklahoma, although the expense of suchpotentials has been pointed out many times. In one of the most recent pools inOklahoma it is the practice to take open-flow potentials through the casingwith the tubing out of the hole. The well is usually tubed after it is drilledin for the purpose of washing it in and cleaning the hole. After preliminarytests are run the tubing is pulled under pressure preparatory to taking thepotential. After the potential is taken the tubing is rerun, under pressure. Inorder to accommodate the large capacity of the wells, it is customary to setthree separators, six vent lines and large oil-storage tanks. It isconservatively estimated that the equipment not needed for producing the wellcurrently but which is installed solely for the purpose of establishing largepotentials costs the operator at least $5000 per well-approximately 35 per centof the cost of equipping a well for production. Such needless expenditureconstitutes an economic waste in addition to the gas that is wasted in takingpotentials. Meaning of Productivity Index A method of measuring the relative ability of wells to produce without openflow that shows considerable promise is the Productivity Index.

A New Method for Measuring Vented Gas

Because of the necessity for taking regularly occurring open-flow tests inprorated high-pressure oil fields, much gas is turned to atmosphere by way ofvertical vent lines leading away from the oil and gas separator. In the past, measurement of such gas has been accomplished by several methods, usually byuse of the open-flow Pitot tube. The use of the closed-flow Pitot tube has beenavoided apparently chiefly because the ordinary vent-line hook-up makes itnecessary to apply the instrument closer to a bend, valve, or obstruction inthe pipe than is recommended by rules of good practice. The many advantages that would result from the application of the closed-flowPitot tube prompted investigation of the actual effect upon quantity rate offlow measurements computed from data obtained with the tube in a normal workingposition, which is closer to the tee at the base of the vent riser than isusually considered as giving highly accurate results. An effort was first madeto compare the results thus obtained to those under ideal conditions and athigh velocities. To make this comparison, knowledge of the characteristics of gas flowing atvery high velocities is essential. Research for such information indicated thatlittle or no work had been done that would give data necessary for such acomparison, therefore the problem was changed to a test designed to determinethe relationship between quantity rates of flow as measured by an orifice meterand a Pitot tube placed at the center of a pipe eight diameters from a tee orell at the base of a vent riser, through which gas is flowing under lowpressures at very high velocities. To determine this relationship, a series of tests was run on a number of 8-in.iron-pipe vent risers in which the Pitot tube data were taken at the positionas stated above. Gas from a wet-gas gathering system was passed through anorifice meter setting and thence to atmosphere by way of the vents. Data were taken simultaneously from the orifice meter and Pitot tube from whichcomputations for comparisons were made. The actual method of comparison isdiscussed later in this paper.