Apparatus and process for treating water

Abstract

A system that uses thermal addition, particle size reduction, increasing surface area, pressure reduction and kinetic energy increases to vaporize and dewater wastewater and/or sludge and/or other liquids mixed with entrained solids to produce a cleaned water condensate and a dewatered solid product. The wastewater and/or sludge enters a cylindrical drum through a rotary entrance valve. A rotating hammermill inside a drum with an exterior thermal jacket pulverizes the entering wastewater or sludge with rotating blades that keep the pulverized product against the inside of the drum's inside surface to vaporize water to separate it from solids. The vaporized water is condensed and discharged from the system and a solid product exits the drum via rotary valves. A vacuum is maintained on the drum to enhance the system.

Claims

1. A water treatment apparatus for receiving water with solids therein to separate substantially all of the water from the solids, the apparatus comprising: an elongated cylindrical drum surrounded by a heated jacket and having spaced apart ends, a top, and a bottom, the drum adapted to receive the water with solids at the top and midway between the ends; a central core rotatably housed in the drum, the core supporting a plurality of elongated hammers pivotally extending outwardly therefrom, and where the central core is adapted to selectively rotate inside the drum to forcefully move the hammers proximate the inner surface of the drum to drive entering water with solids against the inner surface of the drum to produce water vapor thereby separating the water from the solids; an exit port at each end of the drum proximate the top and adapted to permit the water vapor to exit the drum for subsequent condensation back into water; a rotary valve at each end of the drum proximate the bottom and adapted to receive solids and dispense the solids from the drum; and, a vacuum pump proximate the drum communicatively coupled to the drum to maintain a vacuum inside the drum during operation.

2. The apparatus as defined in claim 1 further including a condenser proximate the drum communicatively coupled to the drum to receive the water vapor from the drum and to condense the water vapor.

3. The apparatus as defined in claim 1 wherein the drum has an enlarged portion with a diameter proximate at least one end that is larger than a middle portion of the drum to accommodate larger quantities of water with solids.

4. The apparatus as defined in claim 1 wherein the drum has an enlarged portion with a diameter proximate both ends that is larger than a middle portion of the drum to accommodate larger quantities of water with solids.

5. A water treatment apparatus for receiving water with solids therein to separate substantially all of the water from the solids, the apparatus comprising: an elongated cylindrical drum surrounded by a heated jacket and having spaced apart ends, a top, and a bottom, the drum adapted to receive the water with solids at the top and midway between the ends; a central core rotatably housed in the drum, the core supporting a plurality of elongated hammers pivotally extending outwardly therefrom, and where the central core is adapted to selectively rotate inside the drum to forcefully move the hammers proximate the inner surface of the drum to drive entering water with solids against the inner surface of the drum to produce a thin film that promotes water vapor formation thereby separating the water from the solids; an exit port at each end of the drum proximate the top and adapted to permit the water vapor to exit the drum for subsequent condensation back into water; a rotary valve at each end of the drum and proximate the bottom and adapted to receive solids and dispense the solids from the drum; a vacuum pump proximate the drum communicatively coupled to the drum to maintain a vacuum inside the drum during operation; and, a condenser proximate the drum communicatively coupled to the drum to receive the water vapor from the drum and to condense the water vapor.

6. The apparatus as defined in claim 5 wherein the drum has an enlarged portion with a diameter proximate at least one end that is larger than a middle portion of the drum to accommodate larger quantities of water with solids.

7. The apparatus as defined in claim 6 wherein the drum has an enlarged portion with a diameter proximate both ends that is larger than a middle portion of the drum to accommodate larger quantities of water with solids.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) In the following drawings, which form a part of the specification and which are to be construed in conjunction therewith, and in which like reference numerals have been employed throughout wherever possible to indicate like parts in the various views:

(2) FIG. 1 is schematic diagram of the process in accordance with the present invention;

(3) FIG. 2 is a side elevational view of the vaporizing hammermill with portions omitted or shown in section for clarity; and

(4) FIG. 3 is a side elevational view of another embodiment of the vaporizing hammermill with portions omitted or shown in section for clarity.

DETAILED DESCRIPTION OF THE INVENTION

(5) With reference now to the drawings FIGS. 1-6, one exemplary embodiment in accordance with the present invention is shown.

(6) The system generally includes the following:

(7) 1. A drum or cylinder for the main vessel that is used to convert the water in the sludge to vapor.

(8) 2. A high speed rotating assembly centered within the drum.

(9) 3. Blades that are attached to the rotating assembly. These blades impact the sludge and pulverize it and perform several functions. These blades produce kinetic energy when they impact the sludge. The kinetic energy produced is the mass times the velocity squared. Therefore each time the velocity is doubled, the energy produced is quadrupled. These blades reduce the particle size of the sludge (i.e. pulverizing it) and increase the surface area of the sludge in its pulverized state. These blades also propel the sludge and the dewatered product (i.e. pulverized sludge) toward the inner wall of the inside of the drum. Almost all of the vaporization of the water in the product/sludge takes place at the intersection of the outer end of the blades and the inside of the heated drum. This distance is a very short distance and the product/sludge is kept in a thin layer against the inside of the heated drum. If the sludge attempts to build up on the inside, the blades impact it and this prevents the buildup. Any buildup could inhibit energy from being transferred into the sludge through the wall of the drum. The blades are so aligned and spaced as to allow the water vapor to move through them toward the ends of the cylinder so that it can exit through the vapor lines to the condenser while at the same time limiting the entry of the product sludge inside the blades. The solids are kept against the inside of the drum by the pressure and centrifugal force of the rotating member and blades.

(10) 4. The rotating assembly is sealed between the shaft and the drum so that a deep vacuum can be maintained.

(11) 5. A rotary feed valve to allow product to be introduced into the sealed system while maintaining a deep vacuum. This is typically located at the centerline of the drum but can be located at the outer end of the drum if it is a smaller system. If the inlet rotary valve is located at the centerline of the drum, two rotary valves are used as exit valves (one at each drum end) at the bottom of the drum. If only one rotary inlet or feed valve is used on one drum end, then one exit rotary valve can be used on the opposite end at the drum bottom (when the valves are of the same approximate volume).

(12) 6. One or more rotary valves are used that allow the dewatered product to be removed from the sealed process while it is under a deep vacuum. As the liquid water changes phases from liquid to vapor, it expands 1600 times in volume at the same pressure. However, since the system is operated under a deep vacuum, the vapor expands around 12,000 times in volume at the same pressure. This vapor (that is removed from the sludge through the vapor removal lines that are located on the ends of the drum) is the motive force that moves dewatered sludge from the centerline of the drum toward the outside where it exits the system through the rotary valves.

(13) 7. Vapor lines that transport the water vapor to a condenser.

(14) 8. A condenser. This condenser can be either a shell and tube condenser or an atmospheric condenser. The preferred condenser for this process is the shell and tube condenser if there is ample water for cooling. This system was primarily developed for plants that use a large amount of water. This water, after it has been cleaned in the DAF system is used for the condensing. The condenser is a counter flow design that sues cooling water which has a turbulent flow instead of laminar flow.

(15) 9. A vacuum pump capable of pulling a deep vacuum on the entire system.

(16) 10. A thermal heat unit or a steam boiler for heat in the heat jacket surrounding the drum. The thermal fluid or steam is also turbulent flow inside this heating jacket. Because this system is operated under a deep vacuum, the water changes phases at a much lower temperature. This is an important feature of this process as it allows for a greater temperature differential between the product inside the drum and the thermal fluid/steam. This can translate into a much higher production rate than if the product inside the drum was a higher temperature.

(17) 11. A system for collecting condensate from the condenser. This system uses two tanks. One tank is under vacuum while the second tank is not under vacuum. The first tank is under vacuum and accepts the condensate until it reaches capacity and the condensate is then directed to the second tank and the vacuum is switched to the second tank as well. Thus, only one tank is under vacuum at a time. The tank not under vacuum is drained and then can be used to collect condensate again. The valves that discharge the condensate as well as open vacuum to the other tank are operated simultaneously so that vacuum is always present in the entire process. The only part of the process that does not have a deep vacuum on it is the tank that is discharging.

(18) The system generally operates in steady state. The thermal fluid or heat is established at a level that is preset and maintained during operation. Next the rotating assembly is started rotating. Then a vacuum is established. Cooling water is pumped through the condenser and maintained at a constant flow through the shell and tube condenser during system operation. The vacuum inside the entire process is established and maintained as well. Then sludge (or other wastewater) is introduced through a rotary valve located at the centerline of the drum. This sludge is introduced while the internal rotating assembly is turning at a high rate of speed. The rotating assembly propels the sludge toward the outside of the drum to keep it in contact with the heated surface of the drum while maximizing surface area. This is one important aspect of this process. Unlike heating a product inside a vessel because the heat is only applied to the outside while the rest of the product is heated by radiation. The blades on the rotating assembly produce a very fine mist (within the product) as well as keeping the product in contact with the heated area of the drum. The blades on the rotating assembly also produce kinetic energy by impacting the sludge. The kinetic energy produced is equal to the mass times the velocity squared. The blades in this process are moving at a very high speed. So every time the velocity is doubled, the energy produced is quadrupled. Since the process uses both kinetic energy and thermal energy from an outside source, it is a hybrid process.

(19) As the water in the sludge/water product vaporizes, it travels through the vapor removal piping (which may be inclined upwardly at the drum so any inadvertent sludge/water drops are returned to the drum) to the condenser. In the condenser, the water vapor is returned back to its original state of liquid. The liquid water is then drained into a condensate removal system that empties into the sewer. Since the water is drained into the sewer, there is very little odor. The solids that were in the sludge when it was introduced are driven toward the outer edge of the rotating assembly and are propelled from the center of the system toward the ends by the action of the water vapor produced when the water is vaporized. As water changes phases under a deep vacuum (e.g. 26 vacuum inches), it increases in volume (at the same pressure) 12,000 times and this is the motive force to move the dewatered product toward the outer ends of the drum. The solids are emptied from the outer edge of the drum through one or more rotary valves. Thus, substantially all of the water vaporization happens at the blade ends and against the drum since the center of the rotating assembly is solid.

(20) Several important considerations for this process and apparatus are:

(21) 1. It is a continuous operation.

(22) 2. It is easily managed.

(23) 3. The system reduces transport costs significantly.

(24) 4. The system reduces environmental concerns.

(25) 5. The system controls odor.

(26) 6. The system is substantially sealed.

(27) 7. The system uses a method to control the feed rate of input materials

(28) 8. The system provides a way to produce kinetic energy inside the sludge and also heats the sludge through a thermal jacket surrounding the drum.

(29) 9. The system provides a means to keep the product from building up on the heated surface inside of the drum.

(30) 10. The system provides a method to keep the product in contact with the heated drum surface.

(31) 11. The system provides a way to increase the surface area being heated.

(32) 12. The system provides a way to reduce particle sizes in the drum and it also presents a pulverized product to the heated drum surface in a thin layer.

(33) 13. The system provides a unique way to move the product through the system from entry to exit.

(34) 14. The system provides a way for the water vapor to exit through the hammers and into the condenser.

(35) 15. The system provides an excellent way to remove the condensate from the condensate tanks.

(36) 16. The system requires a relatively small space or footprint for installation.

(37) 17. The system may be implemented economically.

(38) 18. The system may be easily maintained.

(39) 19. The system uses thermal addition, particle size reduction, increasing surface area, pressure reduction and kinetic energy increases to vaporize and dewater wastewater and/or sludge to produce a cleaned water condensate and a dewatered solid product.

(40) In FIG. 1, the system is generally indicated by reference numeral 20. A drum 40 receives entering product through a rotary valve 42. The drum 40 has a thermal jacket 44 that receives thermal fluid/steam to heat the outer drum wall 46. The drum 40 houses an internal rotating assembly with elongated blades (hammermill). The vaporized water leaves the drum through piping 48. Dewatered product leaves the drum through exit rotary valves 49. The dewatered product can include oils and greases or precipitated salts or other contaminants from the entering wastewater and/or sludge.

(41) The drum jacket 44 receives thermal fluid or steam from a thermal fluid supply tank 50 via supply line 52. Spent thermal fluid is returned to the tank via return line 54.

(42) The vaporized water enters the condenser 60 through piping 48. The condenser receives cooling water through line 62 and spent cooling water exits the condenser through line 64. Condensate leaves the condenser through exit line 66 and enters the condensate tanks 70.

(43) Condensate tanks 70 include at least one tank 72 with vacuum valves 74, 76 and a discharge pipe 78. A vacuum line 82 secures the vacuum pump 80 to the tanks 70. Essentially all of the water is condensed out before the vacuum pump and so a relatively small vacuum pump can be used to address any leakage into the system.

(44) The drum 40 houses an internal rotating assembly 100. The rotating assembly 100 has a solid central core 102 extending through the drum 40 and driven at each end by electric motors 110. The central core is appropriately sealed with bearings and races to facilitate its rotary movement relative to the drum. The central core 102 supports multiple swingable hammers or blades 105 that pivotally extend outwardly from the core 102. These hammers (or blades) are essentially rigid when rotated at high speed even though they are each pivotally secured at the central core 102. When the core is rotated the blades 105 protrude toward the exterior drum wall 46 and travel relatively close to the wall with a clearance of less than a one inch and preferably closer and ideally less than a quarter of an inch. This close clearance presents the pulverized product in a thin layer against the hot inside surface of the drum, which enhances vaporization.

(45) In a second embodiment shown in FIG. 3, the drum 40 is changed to accommodate higher production rates to prevent water vapor was taking solids with it on the way to the condenser. At lower rates this is not a problem but at substantially higher rates, sometimes the water vapor and solids can take the same pathway out of the drum. To address this issue, the drum diameter is increased at the ends by approximately 3 inches (i.e. last 10 inches of the drum at each end has a diameter of 54 inches) while the rest of the dimensions remain unchanged. The hammers at these end areas are also three inches longer. This larger diameter enables the solids to be propelled into these areas and then discharged through the rotary valves at the bottom. The water vapor continues to move out of the drum in same manner as before.

(46) These larger areas are also heated by an external thermal jacket. This also insures that the solids are even more de watered as they are heated in this area without being in the presence of saturated water vapor.

(47) The present invention provides several advantages including: 1. This increases the surface area of the product being vaporized; 2. This lowers the partial pressure of the product being vaporized; 3. This adds heat energy to the product being vaporized; 4. This process creates kinetic energy; 5. This keeps the product exposed to the heated surface in a thin layer; and, 6. This process is so designed that the velocity of the water vapor is the motive force used to move the product through the system.

(48) The apparatus and process of the invention is capable of receiving additional, optional features which are not a part of the present invention. For example, a purchaser or user may specify an optional components or features that may be included to facilitate control and/or handling of the system during operation. Also, while examples have discussed wastewater and/or sludge it is to be appreciated that the present invention may be advantageously utilized with similar liquids containing solids (e.g. milk and the like). Other optional features, some of which may be illustrated herein, may or may not be included with apparatus incorporating the basic aspects of present invention. For example natural gas fueled engines, waste heat from internal combustion engines, etc. are options that could be utilized with the present invention.

(49) In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology has been used for the sake of clarity. However, the invention is not intended to be limited to the specific terms selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.