1. Field of the Disclosure
This disclosure is directed to economical systems and methods for facilitating the control of dissolution of one or more gases into a liquid with little to no external energy input.
2. Background of Related Art
Many different systems and methods, depending on application, are available for dissolving gases in liquids. Some of the main applications are in the areas of water and wastewater treatment for municipal, commercial, and industrial uses; aquaculture; ground water remediation; ecological restoration and preservation; beverage making and bottling, and agriculture. Most dissolved gas delivery methods (i.e. bubble diffusion, Venturi injection, U-tubes, Speece cones) attempt to leverage Henry's Law to achieve a high concentration of dissolved gas in the carrier stream. These typically require high flow and/or high pressure from side-stream pumping in order to achieve high rates of gas dissolution.
Higher operating pressures lead to higher gas concentrations; however, this must be balanced with higher operating costs associated with achieving higher pressures. While there are variations between existing technologies operating parameters, all technologies requiring side-stream pumping operate under the same physical laws. Generally, these technologies create a large gas/liquid interface and subject it to elevated pressures for a period of time, subsequently increasing dissolved gas concentration within the liquid. All ultimately require that the gas and the liquid be in contact at the desired pressure.
Certain technologies provide energy input into the liquid and/or gas (e.g., via pumping) to achieve desired vessel pressure. Some technologies provide energy input into the liquid, with an additional energy added, such that a venturi injector can be utilized to create a vacuum allowing the gas to enter without additional energy input from the gas source.
Through algebraic manipulation, an equation can be developed for the efficiency of any side-stream saturation device, in terms of mass/time/energy (lb/d/hp).
E=(1/694.444*((P/Kh)*(s/100))*8.34)/(1*((P+L)*2.3097)/3960/(i/100)). As seen above, this equation only considers the following: Side-stream pressure requirement (P, psi), Henry's Law Constant (Kh, L*psi/mg), Percent of Saturation Achieved (s, %), Headloss Across System (L, psi), and Pump Efficiency (I, %).
For the purposes of discussion here, oxygen will be the gas of choice. However, those skilled in the art will readily recognize the method/apparatus disclosed here can be applied to any gas/liquid dissolution combination. Supplement 1 (with reference to
The effect of side-stream pumping and associated pump efficiencies can be seen in Supplement 3 (as shown in
Supplement 4 appended hereto shows total energy requirements, side-stream pumping plus gas generation, for various oxygen dissolution technologies and approaches, as well as that of embodiments of the system disclosed herein. As can be seen, eliminating side-stream pumping requirements reduces the overall power consumption by about 60%.
For the most part, existing technologies involve side-stream pumping and either pressurized gas sources or gas sources under vacuum. While higher operating pressures lead to higher gas concentrations, to achieve these higher pressures, higher costs are involved.
Therefore, a simplified, low cost, method for dissolving a gas into a liquid, preferably while also maintaining a particular constant flow rate of said liquid is needed. Embodiments of this disclosure can eliminate the requirement for side-stream pumping and greatly reduces operating cost of side-stream gas dissolution systems.
Embodiments of this disclosure are directed to simple and economical systems and methods for facilitating the control of dissolution of one or more gases into a liquid, such as water, without external energy output. Gases for use with the disclosed systems and methods include, e.g., air, oxygen, ozone, and carbon dioxide. However, those skilled in the art will readily recognize the applicability of any suitable gas. Certain applications include, for example, treatment of process basins, pipes and piping systems, rivers, streams, lakes, and ponds, in municipal, industrial, or natural settings.
More specifically, embodiments of this disclosure are directed to systems for gas dissolution into a liquid that include, inter alia, a dissolution tank assembly that has a pressure vessel, source of pressurized gas, and control valves capable of dissolving the pressurized gas into the liquid at elevated pressures. The dissolution tank also includes at least one liquid control valve that permits passage of the fluid into and out of the vessel; said outlet fluid having a desired gas concentration from the pressure vessel. Embodiments of systems of this disclosure further include a gas source in communication with the vessel and a gas supply header and gas supply piping. Also provided is a gas inlet device for generating a large gas/liquid interface area. The saturated liquid is expelled through the liquid flow control valve and inlet/outlet piping. A device for venting stripped and/or undissolved gas is provided as a means of controlling multiple concentrations in the liquid and gas phases.
In certain embodiments, a method includes recapturing the energy associated with motive force of the entering and exiting water. Embodiments of this disclosure include separate inlet and outlet flow control valves and an energy recovery device, such as a micro-turbine.
Certain embodiments makes use of multiple vessels in a series with a combination of interconnected valves, piping, and appurtenances to provide a more consistent output. Embodiments of this disclosure can include a series of high and low pressure manifolds and associated valves such that the gas headspace in one vessel can be vented to another vessel allowing for greater flexibility in operations and ensuring maximum utilization of produced gases. Additionally, in such embodiments, excess gas under low pressure can be added to vessel discharge utilizing venturi principles.
An additional embodiment employs the energy recovery device in combination with the plurality of vessels. This embodiment provides consistent output and increases the overall system efficiency.
In accordance with at least one aspect of this disclosure, a system for dissolving gases into a liquid without side-stream pumping includes, inter alia, a pressure vessel defining an internal chamber configured to hold a liquid and to provide a gas head space above the liquid. The pressure vessel can define a liquid inlet and a liquid outlet. A gas inlet device can be disposed within the internal chamber of the pressure vessel and can be configured to allow gas to enter the pressure vessel. A gas source can be in selective fluid communication with the gas inlet device and the internal chamber of the pressure vessel through a gas control valve to supply a gas to the pressure vessel. The gas source is configured to provide a gas pressure. A liquid inlet pipe can be in selective fluid communication with the liquid inlet of the pressure vessel through a liquid inlet valve. An outlet pipe can be in selective fluid communication with the liquid outlet through a liquid outlet valve for discharging the liquid from the internal chamber of the pressure vessel. The gas pressure both facilitates the dissolving of the gas in the liquid and forces the liquid out of the pressure vessel when the liquid is exposed to the gas pressure.
The gas inlet device can be configured to introduce pressurized gas into the liquid. The surface area of the gas inlet device can be at least half of the surface area of a bottom of the pressure vessel or any other suitable surface area.
The system can further include an energy recovery device. The energy recovery device can be a micro-turbine, for example.
In certain embodiments, the outlet pipe and the inlet pipe can be the same pipe and the liquid inlet valve and the liquid outlet valve can be the same valve.
The system can further include plurality of pressure vessels connected in a series and configured to supply a constant flow output. Moreover, the system can include an energy recovery device connected to at least one of the plurality of pressure vessels.
It is envisioned that in certain embodiments, the system can further include a control system. The control system can be configured to open the liquid inlet valve to allow liquid to flow into the internal chamber until a first predetermined condition occurs, open the gas control valve after closing the liquid inlet valve to pressurize the internal chamber with the gas until a second predetermined condition occurs, and open the liquid outlet valve to effuse the liquid from the internal chamber. The control system can include any suitable electronics, hardware, software, or the like as is understood by those skilled in the art.
The first predetermined condition can include, for example, at least one of a time or a fill level of the internal chamber. The second predetermined condition can include, for example, at least one of a time, a pressure of the internal chamber, a dissolution rate of the gas into the liquid, or a gas content of the liquid.
Embodiments of the system can include a venturi disposed in fluid communication with the liquid outlet pipe and configured to add the gas from the gas head space to an outlet flow.
In accordance with at least one aspect of this disclosure, embodiments of the disclosed system can include a floating vessel including a submerged portion configured to sit below a water level of a body of water, and a pressure vessel as described herein disposed within the submerged portion.
In certain embodiments, the gas source can also be disposed within the submerged portion of the floating vessel. The submerged portion can connect the liquid inlet of the pressure vessel to the body of water.
In accordance with at least one aspect of this disclosure, a method for dissolving a gas into a liquid without pumping can include opening a liquid inlet valve to allow a liquid to flow into an internal chamber of a pressure vessel until a first predetermined condition occurs, opening a gas control valve in fluid communication with a gas source after closing the liquid inlet valve to pressurize the internal chamber with a gas of the gas source until a second predetermined condition occurs, and opening the liquid outlet valve to effuse the liquid from the internal chamber.
These and other features and benefits of the embodiments of this disclosure and the manner in which it is assembled and employed will become more readily apparent to those having ordinary skill in the art from the following enabling description of embodiments of this disclosure taken in conjunction with the drawings described below.
So that those skilled in the art to which the subject invention appertains will readily understand how to make and use embodiments of the systems and methods of this disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
These and other aspects of the subject invention will become more readily apparent to those having ordinary skill in the art from the following detailed description of the invention taken in conjunction with the drawings.
Disclosed herein are detailed descriptions of specific embodiments of the systems and methods of the present invention for dissolving a gas into a liquid without the use of external energy input. It will be understood that the disclosed embodiments are merely examples of ways in which certain aspects of the invention can be implemented and do not represent an exhaustive list of all of the ways the invention may be embodied. Indeed, it will be understood that the systems, devices, and methods described herein may be embodied in various and alternative forms. The Figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. Well-known components, materials, or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure.
Figures illustrating the components show some elements that are known and will be recognized by one skilled in the art. The detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention.
A method is disclosed herein that allows an operator to manipulate the dissolution of a gas into a liquid without using any external energy input. The available atmospheric pressure is sufficient when a liquid control value is opened, allowing the liquid to flow into the pressurized vessel.
As will be described herein below, an embodiment of a method used to increase gas transfer within the vessel involves opening a liquid control valve such that liquid flows via available atmospheric pressure into the pressure vessel, without any external energy input. Once the desired liquid level is achieved, a liquid control valve closes and the gas control valve is opened. The gas flows into the pressure vessel at a rate dictated by the pressurized gas source. As pressure in the vessel increases toward the regulated pressure of the gas source, dissolved gas concentrations within the liquid increase proportionally according to Henry's Law. After a predetermined pressure or time has been achieved, the gas supply control valve is closed and the liquid control valve is opened. The elevated pressure within the vessel provides energy required to expel the saturated liquid through the liquid flow control valve.
Referring now to
As shown in
Embodiments of this disclosure can be applied to any suitable installation scheme, such as embodiments thereof shown in
Embodiments of this disclosure may be operated with a plurality of pressure vessels 100 to provide for continuous output and/or to ensure full utilization of produced gas. Supplement 5, below, shows examples of system sizing and batch operation scheduling designed to provide continuous output of dissolved gas. Supplement 5.1a and Supplement 5.2a show sizing calculations for a reactor with the exact same properties in height, diameter, area, and volume. The difference can be seen in the inlet diameter and the gas flow. Supplement 5.1b and 5.2b demonstrate how batching operations for the designs shown in Supplements 5.1a and 5.2a could operate to produce consistent output.
The logic behind the design of the present invention is that gas dissolution will always require a gas supply. To achieve rapid and efficient gas dissolution elevated pressures are required. Industrial gases can be provided in gaseous or liquid form under pressure. Higher pressures are available at no additional cost. These industrial gases can also be generated on-site. Due to advancements in gas generation technologies, high pressure is available at a small incremental cost.
Gas dissolution does not necessarily require side-stream pumping. The present invention utilizes available liquid head to fill a pressure vessel with liquid, then utilizes available pressure from gas storage tanks, or on-site generators, to not only supply gas requirements, but to also provide energy required for vessel pressurization and motive force required to empty the vessel.
While the subject invention has been described with respect to certain embodiments disclosed above, those skilled in the art will readily appreciate that changes and modifications may be made thereto without departing from the spirit and scope of the this disclosure as defined by the appended claims.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/984,996, filed on Apr. 28, 2014, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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61984996 | Apr 2014 | US |