Submerged combustion water heater
This invention discloses a submerged combustion apparatus and method for heating large quantities of water and other fluids in many applications. Water to be heated exits an orifice opening and flows across a perforated plate where the water is heated by products of combustion passing through apertures in the perforated plate. The low submergence, low backpressure heat and mass transfer arrangement provides an effective and efficient system for heating water and other fluids and concentrating water solutions.
This application claims domestic priority from provisional application Ser. No. 60/516,845, SPIRAL TUBE LNG VAPORIZER filed Nov. 3, 2003 and provisional application Ser. No. 60/511,827, SUBMERGED COMBUSTION WATER HEATER filed Oct. 16, 2003, the entire disclosures of which are incorporated herein by reference. Engdahl U.S. Patent application, SPIRAL TUBE LNG VAPORIZER filed on Oct. 8, 2004 and Engdahl U.S. Patent application SUBMERGED COMBUSTION LNG VAPORIZER filed on Oct. 8, 2004 is incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates generally to heating water. More specifically, the present invention relates to a high efficiency, high capacity, submerged combustion apparatus and method for heating water and other liquids.
BACKGROUND OF THE INVENTIONSubmerged combustion is a high efficiency system for heating water and other liquids. The liquid is heated by direct contact heat and mass transfer with hot products of combustion. The liquid is generally water, but other solutions may be heated. Various systems are employed to provide the direct contact transfer between the products of combustion and the liquid to be heated. The thermal efficiency of a submerged combustion system heating liquids can be higher than 90%. A submerged combustion water heater with a stack gas temperature of 70 degrees F. has a thermal efficiency of about 100%.
The submerged combustion system is used for heating large quantities of liquids at high efficiencies in many industrial and commercial applications. In addition to heating liquids, submerged combustion is utilized for concentrating water solutions by evaporating water from the solution.
The conventional heater is equipped with submerged combustion burners firing into a liquid bath. The products of combustion are discharged into the bath. The discharge location is generally at a liquid submergence depth greater than two feet. The burner system includes a large high horsepower blower for providing combustion air. The submerged combustion burner provides heat, circulation, and turbulence for heat transfer.
There are many patents describing submerged combustion water heaters. The patents describe submerged pressurized products of combustion being bubbled through various combinations of holes and weirs to contact and heat water. The products of combustion are at a pressure sufficiently high to overcome the submergence depth. Deeper submergence depths require larger and higher horsepower combustion air blowers. In an application where the burner assembly discharges into water with an equivalent depth of 48 inches, the blower discharge pressure would need to be 48 inches water column plus the additional pressure drop of the system. Other patents disclose various water spray arrangements contacting the products of combustion to heat water. These patents do not teach or suggest the products of combustion and water flow arrangement of this disclosure nor do they present the arrangement used to contact the products of combustion with the water flow to heat water as taught in this specification.
Objectives
Several objectives of this patent follow:
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- To provide a high thermal efficiency system for heating water and other fluids.
- To provide a submerged combustion system with operates with low combustion gas back pressure.
- To provide a high capacity water heating system.
- To provide a single burner water heating system.
- To provide an arrangement with less potential for apparatus vibration.
- To provide a burner/blower system with low installed horsepower.
- To provide a submerged combustion system heating water with low water pressure drop across the apparatus.
- To provide a high capacity submerged combustion system for heating water circulating in a loop and heating once through water flow applications.
- To provide the heat source for a complete system for vaporizing LNG.
- To provide a submerged combustion system meeting air quality regulations.
- To provide a submerged combustion heater for many commercial and industrial applications including vaporizing water and other fluids and concentrating solutions.
- To provide a system which can be quickly and easily started and shutdown.
In accordance with one aspect of the invention, a submerged combustion water heating apparatus comprising a combustion chamber, a burner assembly firing into the combustion chamber and producing products of combustion, at least one set of perforated plates, wherein the products of combustion flow generally through apertures in the perforated plate, a submerged combustion water inlet plenum, a water inlet means and a submerged combustion water outlet plenum, wherein water is directed through the submerged combustion inlet plenum, through the water inlet means to flow generally across at least one set of perforated plates and be heated by the products of combustion and collected in the submerged combustion water outlet plenum.
In accordance with another aspect of the invention, a submerged combustion method of heating a fluid including the steps of providing a source of products of combustion and a fluid inlet means, providing at least one set of perforated plates, directing fluid to flow through fluid inlet means and generally across at least one set of perforated plates, passing products of combustion through apertures in the perforated plate, contacting the fluid and the products of combustion, heating the fluid using products of combustion and collecting the heated fluid.
In accordance with yet another aspect of the invention, a submerged combustion heat source vaporizer comprising a combustion chamber, a burner assembly firing into the combustion chamber and producing products of combustion, at least one set of perforated plates, wherein products of combustion flow generally through apertures in at least one set of perforated plates, a submerged combustion heat source water inlet plenum, a submerged combustion water inlet means, and a submerged combustion heated water plenum, wherein water is directed through the submerged combustion heat source water inlet plenum and through the submerged combustion water inlet means to flow generally across the perforated plate and be heated by the products of combustion and be collected in the submerged combustion heated water plenum, an annular space, wherein the submerged combustion heated water plenum communicates with the annular space, at least one inlet manifold and at least one outlet manifold, rows of spiral tube heat transfer circuits for containing and vaporizing fluids being positioned generally within the annular space and communicating with at least one inlet manifold, a water outlet plenum communicating with the annular space, wherein the water outlet plenum communicates with the submerged combustion heat source water inlet plenum, and at least one pump circulating water from the water outlet plenum to the submerged combustion heat source water inlet plenum.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention discloses a submerged combustion water heating system which differs from conventional submerged combustion heaters. A unique products of combustion and water flow arrangement provides the heat and mass transfer contact between the water and the products of combustion. The submerged combustion system using this unique arrangement has high efficiency and many advantages.
The submerged combustion arrangement in
Referring now to
The water side of the submerged combustion system is designed in a unique way to accommodate large water flows. These large water flows are heated with efficient contacting means. The required pressure of the products of combustion is low. The inlet water to be heated in
The combustion chamber annular space cooling flow discharge can be routed to join the down corner flow as an alternate to discharging directly into the combustion chamber. The combustion chamber cooling flow discharge could also be piped to another location.
Referring now to
Refer now to
The burner assembly 11 fires into the combustion chamber 12 and produces products of combustion gases. The products of combustion flow from the combustion chamber through apertures in the radial perforated plate 15. The products of combustion heat the water flowing over the perforated plate. The products of combustion exiting the perforated plate are collected in flue plenum 16 and flow through the flue stack 20 to the atmosphere.
The LNG vaporizer device shown in the lower portion of
The LNG vaporizer can be configured with several heat source arrangements and several LNG heat transfer surface area arrangements. The submerged combustion heat source can be located above the heat transfer area or adjacent to the LNG heat transfer surface area. The heat transfer surface area arrangements can include a spiral tube arrangement, a helix arrangement, a serpentine arrangement, or a shell and tube exchanger. The configuration of Engdahl patent application Ser. No. 10/869,086 for a RELIABLE LNG VAPORIZER can provide the LNG heat transfer area. Piping may be required as extensions of the water plenums to connect the various LNG heat transfer surface area arrangements to the submerged combustion heat sources.
In the
The submerged combustion system
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- Control means for varying the heated water outlet flow. Control means for varying the flow can include valves, weirs and variable flow pumps.
- Control means for varying the inlet water flow. Control means for varying the flow can include valves, weirs and variable flow pumps.
- In circulating loop and other applications, control means are employed to maintain the loop water volume or change to a new operating level. If the water volume is increasing or a lower operating level is required, water is discharge water from the loop to obtain the desired water level. If the level is decreasing, make-up water is added to obtain the desired level. Water can also be utilized for cooling when operating in the turndown mode.
- Control means to maintain the water levels within operating limits.
- Burner control system including temperature control.
Additional operational, safety and shutdown functions are included in the submerged combustion control systems.
The submerged combustion water heater can include several arrangements and variations. Variations and arrangements can include one of more of the following:
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- Water can be sprayed or injected into the products of combustion resulting in the production of steam and cooling of the products of combustion.
- Baffles can be positioned in the heated water plenum to assist in the removal of bubbles and entrainment in the heated water.
- Providing refractory insulation on the combustion chamber.
- Providing means to reduce the quantity of liquid droplets leaving via the stack.
- Providing means to control and maintain the pH of the water and solutions within the heater.
- Providing means to improve the air quality emissions from the heater.
- Contacting the products of combustion with a water spray before the products of combustion are vented to atmosphere to increase the heater efficiency.
- Where the fluids to be heated include particulate matter.
The
The submerged combustion system has design flexibility and scalability to adapt to the requirements of the application. The submerged combustion heater can be used for many commercial and industrial applications. Some applications require modification of the outlet plenum system. The submerged combustion system used for snow melting would have a pan located to accept and melt snow. Other shapes can also be utilized to configure the submerged combustion system. They may not be as scaleable as the cylindrical arrangement or provide the uniform distribution obtainable with the cylindrical arrangement.
The heater has installation flexibility. It can be installed below grade, above grade or partly below grade. It can be located onshore and on offshore platforms.
Aqueous and other solutions can be concentrated in the apparatus. The submerged combustion temperature is adjusted to vaporize water or other fluids. The vaporized product leaves via the stack. Provisions can be included to recover vaporized product from the stack gases. The solution remaining in the apparatus is concentrated.
The burner assembly is located in a dry area firing into a large combustion chamber. The large combustion chamber can accommodate a single high capacity, high efficiency, low horsepower, low pressure burner assembly. The low pressure and low submergence in the contact zone and other features of the submerged combustion system reduce the potential for apparatus vibration. The combustion chamber can also accommodate multiple burners. The unique water and products of combustion flow and contact arrangement permits the use of conventional low backpressure type burner assemblies. The burner assembly backpressure would generally be less than one pound per square inch.
The conventional burner assembly used in the invention can more readily meet air quality regulations than the high back pressure submerged combustion burner system. Several means are available to reduce the products of combustion emissions from the submerged combustion burner system. A high performance burner can provide reduced emissions. A further reduction can be obtained by recirculating products of combustion to the burner assembly to reduce the SCV emissions. A products of combustion stream from the flue plenum or flue stack can be recirculated to the burner. The high efficiency submerged combustion heat source produces cool products of combustion in the flue plenum and the flue stack. The cool products of combustion can be recirculated to the burner system. Some applications may require that the cool products of combustion be heated before being recirculated to the burner. The cool flue gas can be heated by indirect heat exchange with the hot products of combustion. In another system the cool flue gas can be heated by blending a portion of the hot products of combustion with the cool flue gas to produce the required gas temperature for recirculation. Another system would use cool products of combustion or flue gas from an external source to lower the SCV emissions. The external source of flue gas could be a gas turbine or another type of fired facility. The arrangement using an external flue gas source could increase the overall energy efficiency of the combined system.
At start-up, the submerged combustion system water flow is established before the burner is started. It is not necessary for the air blower to displace water from a portion of the apparatus before the burner is fired as required by many submerged combustion systems. The time required for burner start-up is low. The total start-up is low. The water flow configuration of the submerged combustion system provides water heating with low pressure drop in the water to be heated circuit.
Features
Several features of this invention Follow:
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- The unique gas and water flow arrangement provides an effective means for heat and mass transfer surface area contact between water and the products of combustion.
- The burner start-up sequence can proceed without the air blower displacing water. The submerged combustion system can be quickly and easily started and shutdown.
- The combustion gas system is configured to operate with low back pressure. The combustion chamber and burner operate at low pressure. The combustion air blower has low installed horsepower.
- The submerged combustion apparatus can provide the heat for a complete system for vaporizing LNG and heating and vaporizing other fluids.
- The submerged combustion system facilitates the installation of high efficiency, high capacity, single burners.
- The low backpressure, low submergence heating system has less potential for apparatus vibration.
- The low pressure burner/combustion chamber arrangement can more readily meet air quality regulations.
- The submerged combustion system can be configured for circulating loop applications and configured for once through heating applications.
- The submerged combustion system can concentrate solutions.
- The submerged combustion heater can be used for many commercial and industrial applications.
- The heater has installation flexibility. It can be installed below grade, above grade or partly below grade. It can be located onshore and on offshore platforms.
- The heater provides fluid heating with low pressure drop in the fluid to be heated circuit.
Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the apparatus may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.
Claims
1. A submerged combustion water heating apparatus comprising:
- a combustion chamber;
- a burner assembly firing into the combustion chamber and producing products of combustion;
- at least one set of perforated plates; wherein the products of combustion flow generally through apertures in the perforated plate;
- a submerged combustion water inlet plenum, a water inlet means and a submerged combustion water outlet plenum; wherein
- water is directed through the submerged combustion inlet plenum, through the water inlet means to flow generally across at least one set of perforated plates and be heated by the products of combustion and collected in the submerged combustion water outlet plenum.
2. The apparatus of claim 1, further comprising one or more from the group consisting of:
- (a) where the products of combustion include vaporized water;
- (b) where an annular plate system is located above a perforated plate;
- (c) where an annular plate system provides space for heat and mass transfer surface area contact between water and the products of combustion;
- (d) where a portion of the water flows through apertures in the perforated plate;
- (e) where the submerged combustion water outlet plenum includes at least one liquid seal to contain the products of combustion;
- (f) where the burner assembly operates with a backpressure of less than one pound per square inch;
- (g) where the water inlet means includes a down corner and orifice opening;
- (h) where water and other fluids are heated and vaporized or heated or vaporized or concentrated;
- (i) where products of combustion are recirculated to the burner assembly;
- (j) where flue products of combustion are heated and recirculated to the burner assembly;
- (k) where flue products of combustion from an external source are routed to the burner assembly;
- (l) where the fluids to be heated or vaporized include particulate matter;
- (m) where the products of combustion are contacted with a water spray.
3. A submerged combustion method of heating a fluid including the steps of:
- providing a source of products of combustion and a fluid inlet means;
- providing at least one set of perforated plates;
- directing fluid to flow through fluid inlet means and generally across at least one set of perforated plates;
- passing products of combustion through apertures in the perforated plate;
- contacting the fluid and the products of combustion;
- heating the fluid using products of combustion; and
- collecting the heated fluid.
4. The apparatus of claim 3, further comprising one or more from the group consisting of:
- (a) where the products of combustion include vaporized water;
- (b) where an annular plate system is located above a perforated plate;
- (c) where an annular plate system provides space for heat and mass transfer surface area contact between fluid and the products of combustion;
- (d) where a portion of the fluid flows through apertures in the perforated plate;
- (e) where the fluid inlet means includes a submerged combustion fluid inlet plenum, a down corner and orifice opening;
- (f) where water and other fluids are heated and vaporized or heated or vaporized or concentrated;
- (g) where products of combustion are recirculated to the source of products of combustion;
- (h) where flue products of combustion are heated and recirculated to the source of products of combustion;
- (i) where flue products of combustion from an external source are routed to the source of products of combustion;
- (j) where the fluids to be heated or vaporized include particulate matter;
- (k) where the products of combustion are contacted with a fluid spray.
5. A submerged combustion heat source vaporizer comprising:
- a combustion chamber;
- a burner assembly firing into the combustion chamber and producing products of combustion;
- at least one set of perforated plates; wherein products of combustion flow generally through apertures in at least one set of perforated plates;
- a submerged combustion heat source water inlet plenum, a submerged combustion water inlet means, and a submerged combustion heated water plenum; wherein
- water is directed through the submerged combustion heat source water inlet plenum and through the submerged combustion water inlet means to flow generally across the perforated plate and be heated by the products of combustion and be collected in the submerged combustion heated water plenum;
- an annular space; wherein the submerged combustion heated water plenum communicates with the annular space;
- at least one inlet manifold and at least one outlet manifold;
- rows of spiral tube heat transfer circuits for containing and vaporizing fluids being positioned generally within the annular space and communicating with at least one inlet manifold;
- a water outlet plenum communicating with the annular space; wherein the water outlet plenum communicates with the submerged combustion heat source water inlet plenum; and
- at least one pump circulating water from the water outlet plenum to the submerged combustion heat source water inlet plenum.
6. The LNG vaporizer of claim 5, further comprising one or more from the group consisting of:
- (a) where a spiral tube heat transfer circuit and annular space is arranged to provide substantially cross flow heat transfer;
- (b) where the vaporizer is provided with an interstage manifold communicating with the spiral tube circuits;
- (c) where the interstage manifold provides means for liquid separation;
- (d) where a spiral tube heat transfer circuit is generally supported on support rods, tubes or bars;
- (e) where the products of combustion include vaporized water;
- (f) where an annular plate system is located above a perforated plate;
- (g) where an annular plate system provides space for heat and mass transfer surface area contact between water and the products of combustion;
- (h) where a portion of the water flows through apertures in the perforated plate;
- (i) where various fluids including LNG are heated and vaporized or vaporized or heated;
- (j) where several heat sources provide the heat or where the water contains particulate matter;
- (k) where products of combustion are recirculated to the burner assembly;
- (l) where flue products of combustion are heated and recirculated to the burner assembly;
- (m) where flue products of combustion from an external source are routed to the burner assembly;
- (n) where the submerged combustion heated water outlet plenum includes at least one liquid seal to contain the products of combustion;
- (o) where other types of heat transfer circuits are included;
- (p) where the burner assembly operates with a backpressure of less than one pound per square inch;
- (q) where water includes fluids and water solutions;
- (r) where rows of spiral tube heat transfer circuits are generally supported on support rods and the support rods for a row are positioned to provide vertical clearance between a row of spiral tube heat transfer circuits and the support rods supporting the row of spiral tube heat transfer circuits located above and allowing independent movement of each row of spiral tube heat transfer circuits;
- (s) where the tube pitch of selected tubes within a spiral tube heat transfer circuit is adjusted to accommodate tube icing or adjusted to accommodate heating medium flow or both.
Type: Application
Filed: Oct 8, 2004
Publication Date: May 19, 2005
Inventor: Gerald Engdahl (Wheaton, IL)
Application Number: 10/961,620