This specification relates to a system and a method for controlling contracting and expanding gases or gas generation inside a closed storage vessel while minimizing or eliminating inhalation or exhalation with the surrounding environment.
Closed storage vessels, such as storage tanks may store volatile liquid, such as gasoline. The volatile liquid inside the vessel can then evaporate, resulting in gas vapors diffusing into the air in the vapor space above the liquid inside the storage vessel. These gas vapors may cause environmental damage if released from the vessel. Accordingly, vessels storing the volatile liquid may be sealed to limit release of the gas vapors. Sealed containers in an open environment are subject to expansion and contraction of the liquid and vapors stored within. For example, when the volatile liquid and vapors expands due to rising temperatures caused by the sun, the pressure within the sealed storage tanks also increases. In some situations, the storage tank may bend outward or even burst open from the increase in pressure. Conversely, when the liquid and vapors contract due to falling temperatures at night, the pressure within the sealed storage tanks decreases. In some situations, the storage tank may bend inward or even implode from the reduction in pressure.
Storage vessels may also store solids and/or liquids that generate additional vapor, such as biodegradable material, in an anaerobic digestion tank, which produces methane and other gases as a result of bacterial action, or crude oil which flashes upon reduction in pressure, releasing hydrocarbon vapors such as methane and butane.
What is described is an apparatus for the storage of atmospheric air inside a storage vessel. The apparatus includes a sealed storage tank having an upper tank opening and defining a tank cavity configured to store volatile liquid and vapors. The apparatus also includes a tube having a top opening and a bottom opening, the top opening positioned outside the tank cavity and the bottom opening positioned within the tank cavity. The apparatus also includes a bag flange located within the tank cavity and having a bottom opening, a top opening connected to the bottom opening of the tube, and a rim surrounding the bottom opening. The apparatus also includes a bag connected to the bottom opening of the bag flange and located within the tank cavity. The bag has an opening aligned with the bottom opening of the bag flange and the bottom opening of the connecting tube. The bag is configured to receive or emit atmospheric air via the tube when the volatile liquid and vapors stored within the storage tank contract or expand due to variations in temperature of the stored vapors, and a weight and a location of the bag within the tank cavity is supported by the bag flange.
Also described is an apparatus for the safe handling and storage of volatile liquid and vapors inside of a tank cavity of a sealed storage tank. The apparatus includes a tube having a top opening and a bottom opening, the top opening positioned outside the tank cavity and the bottom opening positioned within the tank cavity. The apparatus also includes a bag flange located within the tank cavity and having a bottom opening, a top opening connected to the bottom opening of the tube, and a rim surrounding the bottom opening. The apparatus also includes a bag connected to the bottom opening of the bag flange and located within the tank cavity, and a weight and a location of the bag within the tank cavity being supported by the bag flange. The bag has an opening aligned with the bottom opening of the bag flange and the bottom opening of the connecting tube. The bag is configured to receive or emit atmospheric air via the tube responsive to at least one of a change in volume of the volatile liquid stored within the sealed storage tank or a change in volume of the vapors stored within the sealed storage tank.
Also described is an apparatus for the safe handling and storage of matter and vapors created from the matter. The apparatus includes a sealed storage tank having an upper tank opening and defining a tank cavity configured to store the matter and the vapors created from the matter. The apparatus also includes a tube having a top opening and a bottom opening, the top opening positioned outside the tank cavity and the bottom opening positioned within the tank cavity. The apparatus also includes a bag flange located within the tank cavity and having a bottom opening, a top opening connected to the bottom opening of the tube, and a rim surrounding the bottom opening. The apparatus also includes a bag connected to the bottom opening of the bag flange and located within the tank cavity, a weight and a location of the bag within the tank cavity being supported by the bag flange. The bag has an opening aligned with the bottom opening of the bag flange and the bottom opening of the connecting tube. The bag is configured to emit atmospheric air via the tube when the matter stored within the sealed storage tank creates vapors. The bag is also configured to receive atmospheric air via the tube when at least one of the matter or the vapors created from the matter is reduced.
Other systems, methods, features, and advantages of the present invention will be apparent to one skilled in the art upon examination of the following figures and detailed description. Component parts shown in the drawings are not necessarily to scale, and may be exaggerated to better illustrate the important features of the present invention.
Disclosed herein are apparatuses, systems, and methods for the storage of atmospheric air within a vessel or the safe handling and storage of matter and vapors created from the matter. The matter may be a volatile liquid and vapors created therefrom. A liquid with high volatility is one which will easily vaporize, such as gasoline, acetone, butyl acetate, ethanol, and butane, for example. Conventional sealed storage tanks for these volatile liquids contain both the volatile liquid and vapors from the volatile liquid. Sealed storage tanks may create undesirable emissions from working losses or from standing losses.
Working losses occur when liquid is pumped into the sealed storage tank, and as the new liquid enters the storage tank, vapor inside the storage tank is forced out, resulting in emissions. To reduce working losses, when liquid is added to the storage tank, a vapor connection line may be attached from the vapor side of the storage tank to the vapor side of the vessel that is filling the storage tank. As liquid flows out of the unloading vessel into the storage tank, vapor flows from the storage tank to the unloading vessel. This approach is called “balanced loading” and may be used to control emissions from underground storage tanks at gasoline stations.
Standing losses occur due to changes in ambient temperature outside of the storage tank. Sealed storage tanks storing volatile liquid are subject to expansion and contraction forces due to changes in temperature. Some sealed storage tanks containing volatile liquid are located outdoors in areas where there may be a significant difference in the lowest temperature at night and the highest temperature during the day. When the temperature of the volatile liquid and vapors inside the sealed storage tank increases, the volatile liquid and vapors expand, causing pressure inside the sealed storage tank to increase.
Releasing gases from inside a sealed storage tank to the air outside of the storage tank using a relief valve may not be a desirable option, as the release of gases results in emissions that are harmful to the environment. Retaining the pressurized vapors inside the vessel may also not be a desirable option, as the storage tank body has to be reinforced to withstand the expansion and contraction forces and thus cost significantly more money. Furthermore, even reinforced tanks may fail due to excessive pressure or contraction forces significantly larger than their designed pressures. The system and apparatus described herein accommodates for the expansion and contraction of the volatile liquid without deforming the sealed storage tank or requiring reinforcing, and without releasing emissions. In addition, when volatile liquid and vapors are added to the sealed storage tank or removed from the sealed storage tank, the liquid volume and the gas volume occupied within the sealed storage tank may change. The system and apparatus described herein also accommodates for changes in the stored amounts of the volatile liquid and vapors.
Alternatively, the matter stored inside the sealed storage tank may be a solid or semi-solid matter which generates vapors. In some embodiments, the matter is organic waste and the vapors are methane. As the organic waste decomposes inside of the sealed vessel, methane is produced. The methane may be used as a power source. As more methane is created, pressure may build inside the sealed vessel, and releasing the methane into the atmosphere to relieve the pressure is undesirable. The system and apparatus described herein accommodates for changes in the stored amounts of the solid or semi-solid matter and the vapors created therefrom.
The apparatus 100 also includes an emergency pressure vent 170 configured to release pressure from within the sealed storage tank 102 in an emergency situation. The apparatus 100 also includes a vapor balance pipe 172 configured to connect to a vessel that is filling the sealed storage tank 102 with additional volatile liquid. The vapor balance pipe 172 emits vapors from the sealed storage tank 102 to the vessel to address working losses, as described herein.
A bag (or bladder) inside of the sealed storage tank 102 may receive or emit atmospheric air via a top opening 106 of a tube 112. As described herein, the receiving and emitting of atmospheric air by the bag allows the apparatus 100 to maintain a constant atmospheric pressure within the sealed storage tank 102, despite changes in temperature. The top opening 106 may be angled or shielded such that precipitation or debris may be prohibited from entering the bag via the top opening 106.
Referring to
As shown in
A bag flange (or bladder flange) 104 is located within the tank cavity 103. The bag flange 104 is configured to support a weight and location of the bag 114 within the tank cavity 103. The bag flange 104 has a top opening 154 and a bottom opening 158. The bag flange 104 also includes a rim 159 surrounding the bottom opening 158. The bag flange 104 connects the bag 114 to the tube 112. The top opening 154 of the bag flange 104 is connected to the bottom opening 152 of the tube 112. The bottom opening 158 of the bag flange 104 is aligned with a bag opening 161 of the bag 114 such that atmospheric air 150 may freely pass to and from the outside 127 of the sealed storage tank 102 and the interior bag cavity 116.
The bag flange 104 and the tube 112 may be made of a metal, such as steel, which will not react with atmospheric air or the vapors inside the sealed storage tank 102. The bag flange 104, the tube 112, and the sealed storage tank 102 may all be made of the same material or may each be made of different materials.
The bag 114 may be connected to the rim 159 of the bag flange 104. The bag flange 104 may also include a flange plate 160 located within the interior bag cavity 116. The flange plate 160 may connect to the rim 159 of the bag flange 104 using one or more connectors 162, such as rivets, screws, pins, or bolts. The connectors 162 may pass through corresponding holes on the rim 159, the bag 114, and the flange plate 160. The connectors 162 may be threaded, screwed, welded, brazed, or secured by interference fit to connect the flange plate 160 to the rim 159, thereby sandwichably fixing the bag 114 to the bag flange 104.
The apparatus 100 also includes a distance measurement unit 134. The distance measurement unit 134 may be connected to the tube 112 at an opening 163. The distance measurement unit 134 is configured to detect a distance between the distance measurement unit 134 and a fixed location on the interior surface of the bag 114. The distance between the distance measurement unit 134 and the fixed location of the bag 114 may serve as an indicator of the degree to which the bag 114 is inflated. The degree to which the bag 114 is inflated may, in turn, serve as an indicator that further actions may need to be taken not to release vapors into the atmosphere. The distance measurement unit 134 may include a processor and a memory storing instructions for use by the processor to determine various distances, as described herein, and various volumes of the bag 114, as described herein.
The distance measurement unit 134 may use a distance measurement apparatus 138 to determine the distance between the distance measurement unit 134 and a bag plate 136 located on a bottom surface of the interior bag cavity 116 of the bag 114. As shown in
In some embodiments, the distance measurement apparatus 138 is a laser and a sensor. The laser emits a beam of light, which reflects off of the bag plate 136. The reflection from the bag plate 136 is detected by the sensor, and based on a time between emission of the beam of light and the detection of the reflection by the sensor, the distance measurement unit 134 is able to detect a distance between the distance measurement unit 134 and the bag plate 136.
When the distance measurement apparatus 138 is a laser, the opening 163 is at a location on the tube 112 such that the beam of light may pass straight through the tube 112 and into the bag 114, as shown in
The outside 127 of the sealed storage tank 102 has a second temperature 131. In one embodiment, the second temperature 131 is a lower temperature than the first temperature 130 of
As the vapors 156 contract, the atmospheric air 150 is drawn into the bag 114 via the tube 112. In particular, the atmospheric air 150 enters through the top opening 106 of the tube 112, passes through the bottom opening 152 of the tube 112, passes through the top opening 154 of the bag flange 104, passes through the bottom opening 158 of the bag flange 104, and enters the interior bag cavity 116. The bag 114 inflates with the atmospheric air 150 and the bag 114 now has a second amount 117 of the atmospheric air 150 inside of the bag 114. The second amount 117 is greater than the first amount 115 of the atmospheric air 150 inside of the bag 114 in
In addition to the bag 114 having an increased amount of atmospheric air 150 in the interior bag cavity 116, the distance between the distance measurement unit 134 and the bag plate 136 is now a second distance 182. The second distance 182 is greater than the first distance 180. The distance measurement unit 134 may determine the second amount 117 of the atmospheric air 150 inside the bag 114 based on the second distance 182. The distance measurement unit 134 may be connected to a clock and/or a thermometer, and may be able to determine a relationship between the time and/or a temperature and the amount of the atmospheric air 150 inside of the bag 114.
The volatile liquid 118 may also be removed from the tank cavity 103, decreasing the liquid volume of the volatile liquid 118 from the first liquid volume 121 to the second liquid volume 123. Decreasing the liquid volume of the volatile liquid 118 may also cause the bag 114 to inflate, similar to the contraction of the vapors 156 described herein.
The outside 127 of the sealed storage tank 102 has a third temperature 132. The third temperature 132 is a lower temperature than the first temperature 130 of
Again, as the vapors 156 contract, the atmospheric air 150 is drawn into the bag 114 via the tube 112. The bag 114 inflates with the atmospheric air 150 and the bag 114 now has a third amount 119 of the atmospheric air 150 inside of the bag 114. The third amount 119 is greater than the second amount 117 of the atmospheric air 150 inside of the bag 114 in
In addition to the bag 114 having an increased amount of the atmospheric air 150 in the interior bag cavity 116, the distance between the distance measurement unit 134 and the bag plate 136 is a third distance 184. The third distance 184 is greater than the first distance 180 and the second distance 182. The distance measurement unit 134 may determine the third amount 119 of the atmospheric air 150 inside the bag 114 based on the third distance 184.
The volatile liquid 118 may further be removed from the tank cavity 103, causing the liquid volume of the volatile liquid 118 to further decrease from the second liquid volume 123 to the third liquid volume 125. The decreasing of the liquid volume of the volatile liquid 118 may cause the bag 114 to further inflate, similar to the contraction of the vapors 156 described herein.
The states of the apparatus 100 illustrated in
If the bag 114 were not a part of the apparatus 100, the pressure/vacuum relief valve 110 may release vapors 156 into the environment so that the pressure difference between the tank cavity 103 and the outside 127 does not cause the sealed storage tank 102 to deform or rupture.
While the variations in the bag inflation state have been described with respect to the variations in the temperature and volume of the liquids and vapors stored in the tank cavity, adding or removing volatile liquid and/or vapors while maintaining the seal of the sealed storage tank may cause variations in the volume of the atmospheric air inside the bag. For example, if the volatile liquid 118 is removed from the tank cavity 103 in
The bag 114 as shown in
In some embodiments, the tube 112 is made of an upper tube and a lower tube, and each are connected to the manway cover 508. The manway cover 508 is sealed by a gasket located between the manway cover 508 and the manway 103. In some embodiments, the tube 112 is a single tube and the manway cover 508 has an opening 129 for the tube 112 to pass through, and the sealed storage tank 102 may be sealed around a portion 506 of the tube 112 that occupies the opening 129.
The tube 112 may have a straight path from the distance measurement unit through the tube 112 and into the bag 114. The tube 112 may have a curved or bent path from the opening 106 through the tube 112 (which may include two tubes connected to the manway cover 508) and into the bag 114.
The bag flange 104 may have a flange diameter 504. The flange diameter 504 of the bag flange 104 may scale with the dimensions of the bag 114. The bag flange 104 may support the weight of the bag 114 and may establish the position of the bag 114 within the tank cavity 103. Accordingly, as the bag 114 increases in size, the bag flange 104 may also increase in size.
In some embodiments, the flange diameter 504 of the bag flange 104 is between about 6 and 10 percent of the diagonal length 606 of the bag 114. In some embodiments, the flange diameter 504 of the bag flange 104 is between about 6 and 10 percent of the first width 602 of the bag 114. In some embodiments, the flange diameter 504 of the bag flange 104 is between about 6 and 10 percent of the second width 604 of the bag 114. In some embodiments, the flange diameter 504 of the bag flange 104 is between about 6 and 10 percent of the diameter 186 of the bag 114 in a fully inflated state (as shown in
The generally rectangular shape of the bag 114 and the circular shape of the sealed storage tank 102 results in multiple gaps 610 between the bag 114 and the interior wall 612 of the tank cavity 103. The gaps 610 may allow for vapors to freely pass and rise up from the volatile liquid stored below the bag 114, and surround the bag 114.
The systems described herein may also be used to store solid, semi-solid, and/or liquid matter and the vapors produced from the matter. In some embodiments, the matter is biodegradable food waste and the vapors are methane and other vapors produced from the decomposing of the food waste. The methane may be used in other systems as a power source.
When the system 700 is used for storage of biodegradable matter, the sealed storage tank 702 may be constructed to insulate the matter and vapors stored inside. The biodegradable matter may be broken down by bacteria more efficiently at a constant, high temperature. The sealed storage tank 702 may be made of any insulating material, such as ceramic or a multi-layered metal having an insulator disposed between layers, for example.
The system 700 may also include a pressure/vacuum relief valve 710, similar to the pressure/vacuum relief valve 110 described herein. The system 700 may also include a vapor exit tube 772, used to direct vapors out of the sealed storage tank 702. The system 700 may also include a tube 712 similar to the tube 112 having a top opening 706 similar to the top opening 106.
The system 800 includes a pressure/vacuum relief valve 810 and a tube 812 having a top opening 806 and a bottom opening 852. The bottom opening 852 of the tube 812 is connected to a top opening 854 of a flange 804. The flange 804 has a bottom opening 858 connected to a bag opening 861 of a bag 814 connected to the flange 804. The bag opening 814 and the bottom opening 858 of the flange 804 may be aligned so that atmospheric air 850 may freely enter an interior bag cavity 816 of the bag 814. The system 800 includes a distance measurement unit 834 having a distance measurement apparatus 838. The bag 814 includes a bag plate 836. In general, the system 800 has many components in common with the system 100, and similar parts are numbered similarly. One of ordinary skill in the art could freely combine the features of the system 100 and the system 800.
As shown in
As shown in
In
In order to harvest the vapors 856, the vapors 856 may be brought out of the tank cavity 803 via a vapor exit tube 872. In some situations, it may be beneficial for the vapors 856 to be urged or propelled out of the tank cavity 803. The system 800 may include a pump 892 connected to the top opening 806 of the tube 812. The pump 892 may bring in the atmospheric air 850 into the interior bag cavity 816 via the tube 812, such that the bag 814 is purposefully inflated. The arrow 890 illustrates the atmospheric air 850 entering the top opening 806 of the tube 812. As the bag 814 inflates, the vapors 856 are urged out of the tank cavity 803 via the vapor exit tube 872, as illustrated by arrow 894. In order to reliably urge the vapors 856 out of the tank cavity 803, the bag 814, when fully inflated, may occupy substantially all of the vapor space of the tank cavity 803.
Exemplary embodiments of the methods/systems have been disclosed in an illustrative style. Accordingly, the terminology employed throughout should be read in a non-limiting manner. Although minor modifications to the teachings herein will occur to those well versed in the art, it shall be understood that what is intended to be circumscribed within the scope of the patent warranted hereon are all such embodiments that reasonably fall within the scope of the advancement to the art hereby contributed, and that that scope shall not be restricted, except in light of the appended claims and their equivalents.
This application claims the benefit and priority of U.S. Provisional Application No. 62/430,818, filed on Dec. 6, 2016, entitled “System and Method for Reducing Vapor Emissions Out of Liquid Storage Tanks,” the contents of which are herein incorporated by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
62430818 | Dec 2016 | US |