Showing papers on "Ullage published in 1992"

Microwave process seal

Abstract: A microwave process seal and method is provided for use, for example, in the detection of ullage level and flow in a vessel or conduit by detecting the presence of a solid or liquid material in proximity to a microwave detector. Particularly, a horn design is provided in conjunction with, the microwave process seal of the present invention which fits in the mouth of the horn. The microwave process seal is kept as thin as possible to meet pressure requirements. The surface of the seal is oriented at or near the Brewster angle. The Brewster angle is that angle for which there is total transmission across a dielectric boundary for energy that strikes the boundary with a linear polarization.

Hydrogen No-Vent Fill Testing in a 34 Liter (1.2 Cubic Foot) Tank

Abstract: Experimental results of no-vent fill testing with liquid hydrogen in a 34 liter stainless steel tank are presented. More than 40 tests were performed with various liquid inlet temperatures, inlet flowrates, initial tank wall temperatures, and liquid injection techniques. Maximum pressure within the receiver tank was limited to 0.207 MPa (30 psia), and fill levels equal to or exceeding 90 percent by volume were achieved in 40 percent of the tests. Three liquid injection techniques were employed; top spray, upward pipe discharge, and bottom diffuser. Effects of each of the varied parameters on the tank pressure history and final fill level are evaluated. The final fill level is found to be indirectly proportional to the initial wall and inlet liquid temperatures and directly proportional to the inlet liquid flowrate. Furthermore, the top spray is the most efficient no-vent fill method of the three configurations examined. The success of this injection method is primarily due to condensation of the ullage vapor onto the incoming liquid droplets. Ullage condensation counteracts the tank pressure rise resulting from energy exchange between the fluid and the warmer tank walls, and ullage compression.

Hydrogen no-vent testing in a 5 cubic foot (142 liter) tank using spray nozzle and spray bar liquid injection

Abstract: A total of 38 hydrogen no-vent fill tests were performed in this test series using various size spray nozzles and a spray bar with different hole sizes in a 5 cubic foot receiver tank. Fill levels of 90 percent by volume or greater were achieved in 26 of the tests while maintaining a receiver tank pressure below 30 psia. Spray nozzles were mounted at the top of the tank, whereas, the spray bar was centered in the tank axially. The spray nozzle no-vent fills demonstrated tank pressure and temperature responses comparable to previous test series. Receiver tank pressure responses for the spray bar configuration were similar to the spray nozzle tests with the pressure initially rising rapidly, then leveling off as vapor condenses onto the discharging liquid streams, and finally ramping up near the end of the test due to ullage compression. Both liquid injection techniques tested were capable of filling the receiver tank to 90 percent under variable test conditions. Comparisons between the spray nozzle and spray bar configurations for well matched test conditions indicate the spray nozzle injection technique is more effective in minimizing the receiving tank pressure throughout a no-vent fill compared to the spray bar under normal gravity conditions.

Methods and systems for the negative pressure testing of underground storage tanks containing highly vaporous hydrocarbon liquids

Abstract: A method and system for detecting a leak in a high vapor-evolving hydrocarbon liquid underground storage tank filled incompletely with the liquid, wherein there is a projecting fill pipe connected with the ullage which is filled with hydrocarbon vapor and air. A vacuum source is connected to the fill pipe for withdrawing the atmosphere of the ullage and imposing a prescribed negative pressure. While some of the drawn off vapor and much of the air is exhausted to atmosphere, a significant portion of the ullage content is recirculated to build the relative proportion of hydrocarbon vapor to air in the ullage. The ullage is then isolated from the vacuum source and atmosphere, and allowed to stabilize over a predetermined time period with a reduced rate of hydrocarbon vapor release into the ullage. The recirculation and stabilization are then repeated to achieve further saturation of the ullage with gasoline vapor and vacuum is applied to the ullage to reach a predetermined threshold negative pressure in the ullage. Over a predetermined time period successive negative pressure readings are taken to determine if there is a rate of decay which indicates the existence of a leak in the tank.

Microwave apparatus and method for ullage measurement of agitated fluids by spectral averaging

Abstract: A microwave apparatus and method for ullage measurement of agitated materials is provided. The apparatus and method utilize a transformation of the reflected time domain signal into a frequency domain signal. The frequency domain signal is averaged using the natural, inherent weighting associated with the transformation to achieve a unique corrected result. The average frequency domain signal is then used to calculate the average distance for determining the ullage measurement.

Ullage tube viewing device

Abstract: A ullage tube viewing device for visual checking of liquid cargo levels without releasing hazardous vapors is disclosed and a method of quickly installing such device in a ullage tube in the absence of heat.

No-Vent Fill Testing of Liquid Hydrogen

Abstract: A receiver tank test system has been fabricated and tested with liquid hydrogen to evaluate tank filling processes including chilldown and no-vent fill. The test system and the approach employed in conducting the test program is described. Results are presented for a series of chilldown and no-vent fill tests. The effectiveness of spray systems to promote vapor condensation and tank filling was demonstrated. A comparison of the results with and without spray system operation clearly showed the need for condensing hydrogen vapor from the ullage to accomplish complete filling of the tank.

Tanker ship design for reducing cargo spillage

Abstract: A tanker ship (1) has upper and lower tanks (30, 31) for carrying cargo. The upper and lower tanks are separated from each other by an intermediate deck (32). The lower tank is filled with cargo to the intermediate deck such that the cargo is slightly pressurized and there is no ullage space. As the tanker sails, the cargo in the lower tank is likely to change pressure due to temperature changes. These pressure changes are detected by a pipe (40) extending from the lower tank through the intermediate deck up to an ullage space in the corresponding upper tank. A siphon (41) is used to transfer cargo between the upper and lower tanks to equalize the pressures. In the event that the lower tanks is breached, sensors (27) are used to detect the resulting drop in pressure from the lower tank cargo.

Ullage volume sensor

Abstract: A device for measuring the free space in a tank is based on a second order mass spring system in which the spring is formed from the unknown volume (Vullage) of gas above the liquid in the tank and the mass is formed by the piston (3a). The resonant frequency of the system is used to determine the ullage volume above the liquid. This information is used to regulate the filling rate of the tank, said rate being proportional to the ullage volume.

Closed vapor control system for the ullage spaces of an oil tanker, including during a continuous maintenance of an ullage space underpressure

Abstract: Vapors, typically volatile organic compounds, emitted from a vaporizable liquid, typically oil, that is within a tank, typically a ship's tank, are (i) compressed, and (ii) stored in a reservoir that is closed to the atmosphere. The (i) compression typically transpires in and by a series/parallel array of pumps, rotary or reciprocating compressors, to a storage pressure of 150+ PSIA. The several million cubic feet ullage volume of a typical 200,000 ton oil tanker is typically compressed over a few days during and/or after loading, and stored in a typically spherical gas storage tank of some 10-20 feet in diameter. Stored gases are returned to the ullage spaces during offloading of the oil tanks in a closed system. This emission control by vapor recovery is interoperative with related systems and methods (i) to avoid spillage of oil due to the rupture of a ship's tank, and/or (ii) to make and maintain a mixture of gases and vapors within the tank's ullage space to be non-explosive and non-flammable. The first parallel system creates and dynamically maintains a partial vacuum in the tank's ullage space--even as all gases and vapors that are evacuated in order to do so are processed into the emission control system. The second parallel system injects an inert gas into the ullage spaces above the oil in the tanks--even though some of this inert gas becomes part of the compressed and stored gas and vapor mixture, rendering this compressed mixture itself non-explosive and non-flammable.

Emergency transfer of oil from a ruptured ship's tank to a receiving vessel or container, particularly during the maintenance of an underpressure in the tank

Abstract: A system and method to transfer oil cargo from ruptured tank(s) of a tanker to receiving vessel(s) or receiving tank(s), while maintaining a partial vacuum in the ullage space of the ruptured tank(s). A partial vacuum is created and maintained in the ullage space of tank(s) of a tanker to reduce outflow of liquid such as oil in the event of a ruptured tank. The vacuum is continuously maintained in a precise balance responsive to the forces acting on the contents of the tank, which forces change when the tank is ruptured. According to the preferred embodiment of the invention the liquid cargo in the tank(s) of the ruptured vessel is transferred to tank(s) of receiving vessels or any designated receiving tank(s) while maintaining the partial vacuum in the ullage space of the tanks of the ruptured tanker or vessel. The partial vacuum in the ullage space of the ruptured tank must be maintained while the oil is transferred to tanks of a receiving vessel, otherwise catastrophic oil spillage may occur.

Sea water leading device for tanker with horizontal bulkhead

Abstract: PURPOSE:To prevent cargo oil from flowing out in the case of a disaster at sea by slightly opening and closing a pressure relief valve according to a draftignition or the like to slightly reduce the pressure in an ullage space for pushing up the cargo oil higher than a broken port. CONSTITUTION:A pressure relief valve 1 is additively provided at the upper end of a cargo vent pipe 4 in a lower cargo oil tank 6. The relief pressure PO of the pressure relief valve 1 is set in conformity with the following formula (pa+gammaSWXd) - (Pr+gammaoilXhoil+gammaSWXhSW), here each signal expresses as follows: atmospheric pressure as Pa, specific gravity of sea water as gammaSW, draftignition as (d), pressure in an ullage space of a lower cargo oil tank 6 as Pr, specific gravity of cargo oil as gammaoil, thickness of cargo oil in the lower cargo oil tank 6 as hoil, and thickness of oily water layer led into the lower cargo oil tank 6 as hSW. The relief pressure Po is set in conformity with the above formula to prevent the cargo oil from outflow caused by outside sea water led through a broken port 8.

Quenching system to prevent loss of fluidity in a reaction vessel

Abstract: A quench system which can be used to quench a continuous reaction such as the continuous digestion of titaniferous ores with sulphuric acid is provided. The quench system comprises a pressure vessel (1) equipped with a full bore outlet valve (5) connected to a reaction vessel (7) which may require quenching. The pressure vessel is partly filled with a liquid (18) and the ullage is occupied by a gas under pressure, the pressure being sufficient to discharge the liquid through the outlet valve (5) when open. The reaction vessel is equipped with means to detect cessation of stirring therein or power failure and the full bore valve is equipped with means (19) to open when cessation of stirring or power failure is detected. Operation of the quench system enables a reaction to be rapidly cooled and diluted to prevent solidification and the problems associated therewith in the event of the reactants being unstirred.