Abstract: A method for condensing a vapor uses a multi-stage bubble-column vapor mixture condenser that includes at least a first stage, a second stage, and a third stage, each with a carrier-gas inlet and outlet as well as a condensing bath and a volume of carrier gas above the condensing bath. The carrier-gas inlet of the second and third stages is in the form of a sieve plate. The first-stage condensing bath is at a temperature of 60° C. to 90° C. Carrier gas flows at a temperature above 60° C. and up to 93° C. into and through the carrier-gas inlet of the first stage, then into and through the condensing bath in the first stage, and then into and through the volume of carrier gas above the condensing bath in the first stage. The carrier gas then similarly flows through the second- and third-stage condensing baths, each of which is at least 5° C. cooler than the temperature of the condensing bath in the preceding stage.

Abstract: Condensing apparatuses and their use in various heat and mass exchange systems are generally described. The condensing apparatuses, such as bubble column condensers, may employ a heat exchanger positioned external to the condensing vessel to remove heat from a bubble column condenser outlet stream to produce a heat exchanger outlet stream. In certain cases, the condensing apparatus may also include a cooling device positioned external to the vessel configured and positioned to remove heat from the heat exchanger outlet stream to produce a cooling device outlet stream. The condensing apparatus may be configured to include various internal features, such as a vapor distribution region and/or a plurality of liquid flow control weirs and/or chambers within the apparatus having an aspect ratio of at least 1.5. A condensing apparatus may be coupled with a humidifier to form part of a desalination system, in certain cases.

Abstract: Liquid solution concentration systems, and related methods, are generally described. In some embodiments, the system is an osmotic system comprising a plurality of osmotic modules. For example, the osmotic system can comprise a feed osmotic module configured to produce an osmotic module retentate outlet stream having a higher concentration of solute than the retentate inlet stream transported to the feed osmotic module. The osmotic system can also comprise an isolation osmotic module fluidically connected to the feed osmotic module. The osmotic system can also optionally comprise a purification osmotic module fluidically connected to the feed osmotic module and/or the isolation osmotic module. Certain embodiments are related to altering the degree to which the feed osmotic module retentate outlet stream is recycled back to the retentate-side inlet of the feed osmotic module during operation.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: Provided herein are osmotic desalination methods and associated systems. According to certain embodiments, multiple osmotic membranes may be used to perform a series of osmosis steps, such that an output stream having a relatively high water purity—compared to a water purity of an aqueous feed stream—is produced. In some embodiments, multiple draw streams can be used to produce aqueous product streams having sequentially higher purities of water. Certain embodiments are related to osmotic desalination systems and methods in which forward osmosis is used to produce a first product stream having a relatively high water purity relative to an aqueous feed stream, and reverse osmosis is used to perform a second step (and/or additional steps) on the first product stream. In some embodiments, multiple reverse osmosis steps can be used in series to perform a net desalination process.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: The present disclosure is related to hybrid desalination systems and associated methods. The hybrid desalination system can comprise a first desalination unit comprising a reverse osmosis unit and a second desalination unit fluidically connected to the first desalination unit, wherein the second desalination unit comprises a humidification-dehumidification desalination apparatus. The present disclosure is also related to systems and methods for the formation of solid salts using a humidifier. According to certain embodiments, the flow velocity of a gas in the humidifier can be relatively high during the formation of the solid salt. In some embodiments, the humidifier comprises a multi-stage bubble column humidifier.

Abstract: A bubble-column-humidification apparatus includes a humidifier chamber configured to receive the feed liquid from a feed-liquid source. A bubble distributor is contained in the humidifier chamber; and a humidifier bath of the feed liquid is also contained in the humidifier chamber above the bubble distributor. The feed liquid forms a continuous and majority phase of the humidifier bath and fills a majority of the humidifier chamber, which has a width at least twice as great as its height. A lower gas region is located below the bubble distributor and the humidifier bath in the humidifier chamber and is configured to receive a carrier gas from a carrier-gas source and to disperse the carrier gas through the bubble distributor. The carrier gas in the lower gas region has a pressure greater than the hydrostatic pressure of the humidifier bath.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: A feed liquid flows into a second-stage humidifier chamber to form a second-stage humidifier bath. A first remnant of the feed liquid from the second-stage humidifier chamber then flows into a first-stage humidifier chamber to form a first-stage humidifier bath having a temperature lower than that of the second-stage bath. A second remnant of the feed liquid is then removed from the first-stage humidifier. Meanwhile, a carrier gas is injected into and bubbled through the first-stage humidifier bath, collecting a vaporizable component in vapor form from the first remnant of the feed liquid to partially humidify the carrier gas. The partially humidified carrier gas is then bubbled through the second-stage humidifier bath, where the carrier gas collects more of the vaporizable component in vapor form from the feed liquid to further humidify the carrier gas before the humidified carrier gas is removed from the second-stage humidifier chamber.

Abstract: Systems and methods related to desalination systems are described herein. According to some embodiments, the desalination systems are transiently operated and/or configured to facilitate transient operation. In some embodiments, a liquid stream comprising water and at least one dissolved salt is circulated through a fluidic circuit comprising a desalination system. In some embodiments, a portion of the desalination system (e.g., a humidifier) is configured to remove at least a portion of the water from the liquid stream to produce a concentrated brine stream enriched in the dissolved salt. In certain cases, the concentrated brine stream is recirculated through the fluidic circuit until the concentrated brine stream reaches a relatively high density (e.g., at least about 10 pounds per gallon) and/or a relatively high salinity (e.g., a total dissolved salt concentration of at least about 25 wt %).

Abstract: A multi-stage bubble-column vapor mixture condenser includes at least a first stage and a second stage. Each stage includes a condenser chamber including a carrier-gas inlet and a carrier-gas outlet and contains a condensing bath. Carrier gas bubbles from the carrier-gas inlet up through the condensing bath, overcoming a hydrostatic head of the condensing bath, to a volume of carrier gas above the condensing bath. The carrier-gas outlet is positioned with an opening for carrier-gas extraction, and the first-stage carrier-gas outlet is in fluid communication with the second-stage carrier-gas inlet to facilitate flow of the carrier gas through the condensing bath in the first-stage condenser chamber, into the volume of carrier gas above the first-stage condensing bath, and then through the condensing bath in the second-stage condenser chamber.

Abstract: A counter-flow simultaneous heat and mass exchange device is operated by directing flows of two fluids into a heat and mass exchange device at initial mass flow rates where ideal changes in total enthalpy rates of the two fluids are unequal. At least one of the following state variables in the fluids is measured: temperature, pressure and concentration, which together define the thermodynamic state of the two fluid streams at the points of entry to and exit from the device. The mass flow rate of at least one of the two fluids is changed such that the ideal change in total enthalpy rates of the two fluids through the device are brought closer to being equal.

Abstract: Liquid solution concentration systems, and related methods, are generally described. In some embodiments, the system is an osmotic system comprising a plurality of osmotic modules. For example, the osmotic system can comprise a feed osmotic module configured to produce an osmotic module retentate outlet stream having a higher concentration of solute than the retentate inlet stream transported to the feed osmotic module. The osmotic system can also comprise an isolation osmotic module fluidically connected to the feed osmotic module. The osmotic system can also optionally comprise a purification osmotic module fluidically connected to the feed osmotic module and/or the isolation osmotic module. Certain embodiments are related to altering the degree to which the feed osmotic module retentate outlet stream is recycled back to the retentate-side inlet of the feed osmotic module during operation.

Abstract: Described herein are systems and methods for treating an aqueous input stream comprising at least one suspended and/or emulsified immiscible phase (e.g., oil, grease) and, in some cases, one or more additional contaminants, such as solubilized bicarbonate (HCO3?) ions, solubilized divalent cations (e.g., Ca2+, Mg2+), solubilized trivalent cations (e.g., Fe3+, Al3+), organic material (e.g., humic acid, fulvic acid), hydrogen sulfide (H2S), and/or suspended solids. According to certain embodiments, the aqueous feed stream is supplied to a water treatment system comprising a chemical coagulation apparatus and a suspended solids removal apparatus (e.g., a clarifier). Within the chemical coagulation apparatus, an amount of an inorganic coagulant (e.g., aluminum chlorohydrate, polyaluminum chloride), an amount of a strong base (e.g., sodium hydroxide), and an amount of a polyelectrolyte (e.g., polyacrylamide) may be added to the aqueous input stream to form a chemically-treated stream.

Abstract: A multi-stage bubble-column vapor mixture condenser comprises at least a first stage and a second stage. Each stage includes a carrier-gas inlet and a carrier-gas outlet, as well as a condenser chamber containing a condensing bath in fluid communication with the carrier-gas inlet and the carrier-gas outlet. The carrier-gas inlet is positioned to bubble carrier gas from the carrier-gas inlet up through the condensing bath, overcoming a hydrostatic head of the condensing bath. The carrier-gas outlet is positioned with an opening for carrier-gas extraction above the condensing bath, wherein the first-stage carrier-gas outlet is in fluid communication with the carrier-gas inlet of the second stage to facilitate flow of the carrier gas through the condensing bath in the condenser chamber of the first stage and then through the condensing bath in the condenser chamber of the second stage.

Abstract: Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).

Abstract: Water treatment systems and associated methods are generally described. Certain embodiments of the water treatment systems and methods described herein may be used to treat water comprising one or more contaminants (e.g., oil, grease, suspended solids, scale-forming ions, volatile organic material) to remove at least a portion of the one or more contaminants. In some embodiments, at least a portion of the treated water may be used directly in certain applications (e.g., oil and/or gas extraction processes). In some embodiments, at least a portion of the treated water may undergo desalination to produce substantially pure water and/or concentrated brine.

Abstract: An osmotic membrane comprises an active layer and a composite support layer. The active layer selectively allows passage of water molecules but rejects at least some dissolved ions. The composite support layer includes a side that is bonded to the active layer and comprises an electrospun-fiber sub-layer and a phase-inversion sub-layer.

Abstract: A counter-flow simultaneous heat and mass exchange device is operated by directing flows of two fluids into a heat and mass exchange device at initial mass flow rates where ideal changes in total enthalpy rates of the two fluids are unequal. At least one of the following state variables in the fluids is measured: temperature, pressure and concentration, which together define the thermodynamic state of the two fluid streams at the points of entry to and exit from the device. The mass flow rate of at least one of the two fluids is changed such that the ideal change in total enthalpy rates of the two fluids through the device are brought closer to being equal.