The following relates to the green energy arts, steam generation arts, and related arts.
In some illustrative embodiments disclosed herein as nonlimiting examples, a steam generation system includes a silo, a heater, a material transfer system, and a heat exchanger. The silo is configured to receive granular material into the silo at an upper portion of the silo. The heater is arranged at or in the upper portion of the silo to heat the granular material received into the silo. The material transfer system is arranged to remove granular material exiting from a bottom of the silo. The heat exchanger is disposed in a lower portion of the silo and is arranged to contact granular material flowing downward inside the silo.
In some illustrative embodiments disclosed herein as nonlimiting examples, a steam generation method is disclosed which is performed in conjunction with the steam generation system of the immediately preceding paragraph. The steam generation method includes: delivering granular material to the upper portion of the silo of the steam generation system; delivering electricity to operate the heater of the steam generation system; and flowing a heat transfer fluid through the heat exchanger of the steam generation system. In some embodiments, the delivering of the granular material, the delivering of the electricity, and the flowing of the heat transfer fluid are performed concurrently. In some embodiments, the delivering of the electricity to operate the heater comprises generating the electricity from solar energy or from wind energy.
In some illustrative embodiments disclosed herein as nonlimiting examples, a steam generation system includes a silo, a heater, a heat exchanger, a material transfer system, and a storage silo. The silo is configured to receive granular material into the silo at an upper portion of the silo. The heater is arranged to heat the received granular material to generate heated granular material. The heat exchanger is disposed in a lower portion of the silo and is arranged to extract heat from the heated granular material flowing downward in the silo to generate cooled granular material. The material transfer system is arranged to remove the cooled granular material exiting from a bottom of the silo. The storage silo is connected to store the cooled granular material removed by the material transfer system and to transfer granular material from the storage silo to the upper portion of the silo.
Steam generation systems and methods disclosed herein provide either saturated or superheated steam for industrial process use from renewable energy sources such as solar and wind. Hence, such steam generation systems are also referred to herein as green steam systems. Solid particles are used to absorb and store energy from the available renewable sources. When steam is needed, energy is transferred from the solid particles to a heat transfer fluid in a suitably designed heat exchanger. In embodiments in which the heat transfer fluid is water, steam is generated directly and sent to the industrial process. In embodiments in which the heat transfer fluid is not water, a second heat exchanger is suitably used to generate steam from the hot heat transfer fluid. The green steam system is flexible and can be configured with different heat transfer surfaces for different applications. A nonlimiting illustrative example configuration for producing superheated process steam is described in the following.
With reference to
The electric heater 10 operates on renewable energy and is located above an insulated silo 12 where the hot sand is stored. Hence, the insulated silo 12 is also referred to herein as a hot silo 12 or hot sand silo 12. The illustrative heater 10 is disposed above the silo 12, between a hopper 14 and a top 12T of the silo 12; however, it is also contemplated for the heater to be integrated into an upper portion of the silo. The electricity for operating the electric heater 10 may, by way of nonlimiting illustrative example, be generated by a renewable energy source such as electricity from solar energy generated by photovoltaic solar panels, solar thermal collectors, concentrated solar power systems, or so forth; electricity from wind energy produced by a wind turbine farm or the like; or another type of renewable energy. The hot sand particles exit a bottom 12B of the silo 12 and flow under the force of gravity through multiple heat exchanger modules 20, 22, 24, 26 where the sand transfers its energy to the water and steam. The sand exits the heat exchangers modules 20, 22, 24, 26 as cold sand at (in one nonlimiting illustrative embodiment) a temperature between 150° C. (302° F.) and 200° C. (392° F.) and is conveyed to a bucket elevator or other sand transfer system 30 which lifts the cold sand to a top 40T of a second insulated silo 40, also referred to herein as a cold sand silo 40 or cold silo 40, or as a storage silo 40. In the illustrative example, the sand transfer system 30 lifts the cold sand to a hopper 42 at the top 40T of the second insulated silo 40. The delivering of the granular material and the delivering of the electricity and the flowing of the heat transfer fluid can be adjusted to cool the granular material exiting from the bottom 12B of the hot silo 12 to a temperature of 200° C. or lower in some embodiments. When renewable energy is available for the electric heater 10, the sand is removed from a bottom 40B of the second (i.e., storage) silo 40 by a screw conveyor or other sand transfer system and is fed to a bucket elevator or other sand transfer system 44 which lifts the sand to the inlet of the electric heater 10 (e.g., the sand is delivered by the sand transfer system 44 to the hopper 14 located above the heater 10 in the illustrative example of
With reference to
The generating bank module 20 and the superheater module 24 are designed with heat exchanger tubes oriented vertically, as diagrammatically shown in
In some nonlimiting illustrative embodiments, the economizer modules 22 and 26 are designed with heat exchanger tubes oriented horizontally, as diagrammatically shown in
In the illustrative embodiment, the bottom of each economizer module 22 and 26 includes screw conveyors 50 oriented parallel to the long axis of the economizer module. The screw conveyors 50 are adjacent to each other with no gaps in between. The screw conveyors 50 control the flow of sand through the heat exchanger modules 20, 22, 24, 26 by removing sand from the bottom of the economizer modules 22, 26 and transporting it to the inlet (e.g., hopper 42) of the cold silo bucket elevator 30 (see
With reference to
Saturated steam exits the top 70T of the vertical separator 70 and goes through a pipe or the like 78 to a steam accumulator 80 (also indicated in
The green steam system can also be configured to deliver saturated steam instead of superheated steam by using a second generating bank module instead of the superheater module 24.
The heat exchanger modules 20, 22, 24, 26 may in some embodiments be self-contained devices which can be disconnected from the system and removed via a monorail system for maintenance or replacement.
The illustrative heat exchanger modules are arranged in two particle flow paths. However, more than two sands paths are also contemplated for use in the green steam system.
The illustrative examples employ sand as the granular material. Sand is advantageously low cost, with high heat capacity and good flowability. However, other granular materials are contemplated for use in the green steam system, such as gravel, crushed stone, synthetic granular materials, or so forth.
While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.
This application claims the benefit of U.S. Provisional Application No. 63/358,076 filed Jul. 1, 2022. U.S. Provisional Application No. 63/358,076 filed Jul. 1, 2022 is incorporated herein by reference in its entirety
Number | Date | Country | |
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63358076 | Jul 2022 | US |