INTEGRATED HEAT RECOVERY BOILER

Abstract

An integrated heat recovery boiler having two independent gas paths and two means for the generation of steam. The combination of duel gas paths within the same apparatus provides a cost-efficient mechanism to increase the heat energy output of a waste-heat recovery system.

Description

FIELD OF THE INVENTION

The invention relates to water tube boilers, and more specifically, heat recovery water-tube boilers.

BACKGROUND OF THE INVENTION

Gas turbines and reciprocating engines are often used to drive an electrical generator in order to generate electricity. Such an engine can also be coupled with an energy recovery device that generates additional energy. The exhaust or heat output of the engine is captured in order to recover energy that would otherwise be lost. A water-tube boiler can be used in this type of energy recovery system in order to convert the heat from the engine to steam or hot water. The steam can then be used to generate additional electricity, to drive other devices, or for whatever purpose may be desired.

Certain applications require greater amounts of steam than can be generated through the heat recovery process alone. This problem has been conventionally addressed through the addition of a duct burner to the system to further heat the gas output from the engine. The duct burner relies upon supplementary firing to increase thermal input, and, commensurately, steam production.

The problem, however, is that the manufacture of boiler systems having duct burners substantially increases capital costs which often render such a design economically unfeasible. It would be advantageous, therefore, to provide a waste heat recovery boiler system which provides for an increased amount of steam production while reducing the design and manufacturing costs of such a unit.

The instant invention solves the foregoing problem by providing additional thermal input without the need for a duct burner in combined heat and power applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a transverse view of an integrated heat recovery steam boiler.

FIG. 2 is a transverse view of an integrated heat recovery hot water boiler.

FIG. 3 is a transverse view of an alternate embodiment of an integrated heat recovery steam boiler.

FIG. 4 is a transverse view of a second alternate embodiment of an integrated heat recovery steam boiler.

FIG. 5 is a transverse view of a third alternate embodiment of an integrated heat recovery steam boiler.

DETAILED DESCRIPTION

The invention comprises an integrated heat recovery boiler having two independent gas paths and two means for the generation of steam.

Referring to FIG. 1, the invention comprises a water-tube boiler 100 having two gas paths 110, 120 separated by a dividing structure or barrier 130. The boiler recovers energy from engine or turbine output but also utilizes a traditional burner, within the same housing, whenever excess steam is needed. Specifically, a first section 110 of the boiler 100 only receives the gas or exhaust coming from an engine or turbine. This portion 110 of the boiler uses the heat from the gas or exhaust to generate steam which is ultimately separated and/or collected in the steam drum 140. The boiler 100 further includes a second section 120, essentially a small boiler, which can be used to generate additional steam.

The sections are divided by a separating structure 130 which can be a metallic wall, e.g., carbon steel plate, or an insulation board, or a combination of both. The wall 130 separates the sections 110, 120 and prevents heat transfer between sections.

In the steam application, shown in FIG. 1, the upper and lower drums are in-line so that the water-tubes can be arranged to recover heat in a separate pass. In that arrangement, the two sections 110, 120 utilize the same steam drum 140 and the same mud drum 150. It will be noted, as seen in FIG. 2, that the design for hot-water applications relies upon two upper and two lower drums thereby providing two independent circuits for the movement of water within the respective sections.

FIGS. 3-5 illustrate alternate embodiments of the invention for use in steam applications. These alternate embodiments employ a split-lower drum 150, 160 arrangement for use in applications with unbalanced heat transfer between the heat recovery section and the combustion section.

The combination of duel gas paths within the same apparatus, and obviation of the need for a duct burner, provides additional capacity at a reduced cost. One example of an application of such a device today is in the construction of power microgrids. Microgrids typically use small turbines and similar engines for power generation and then couple those with heat recovery units in order to make the system more efficient. The invention disclosed herein can be used to increase efficiency while reducing the overall cost of implementation of the power generation system.

While the invention has been described in reference to certain preferred embodiments, it will be readily apparent to one of ordinary skill in the art that certain modifications or variations may be made to the system without departing from the scope of invention claimed below and described in the foregoing specification.

Claims

1. A dual path integrated boiler comprising a first heat recovery boiler assembly and a second conventional boiler assembly with both assemblies situated in parallel in a housing and substantially separated by a dividing structure wherein each assembly includes an independent gas pathway for the introduction and transmission of thermal energy required for the generation of steam.

2. An integrated waste heat recovery system comprising: a heat recovery boiler section and a conventional hot water boiler section disposed in a single enclosure;said heat recovery section comprising an upper drum, a lower drum, an inlet for the acceptance of heat input, an outlet, and a plurality of boiler tubes;said conventional section comprising an upper drum, a lower drum, an inlet, an outlet, a plurality of boiler tubes, and a combustion chamber defined by a portion of said boiler tubes; and,a separating structure between said heat recovery section and convention section whereby said sections are independent and heat transfer between sections is restricted.

3. The system of claim 2 wherein said separating structure is composed of metal.

4. The system of claim 2 wherein said separating structure is composed of an insulating material.

5. The system of claim 2 wherein said separating structure is composed of a combination of metal and insulating material.

6. The system of claim 2 wherein said heat recovery system is a gas turbine heat waste heat recovery system and said inlet for the acceptance of heat input provides for the acceptance of exhaust gases from a gas turbine engine.

7. An integrated waste heat recovery system comprising: an upper drum;a lower drum;a heat recovery section having an inlet, an outlet, and a plurality of boiler tubes which connect said upper drum and said lower drum;a conventional boiler section having an inlet, an outlet, a plurality of boiler tubes which connect said upper drum and said lower drum, and a combustion chamber defined by a portion of said plurality of boiler tubes;a barrier between said plurality of boiler tubes in said heat recovery section and said plurality of boiler tubes in said conventional section whereby heat transfer between said sections is restricted.

8. The system of claim 7 wherein said barrier is composed of metal.

9. The system of claim 7 wherein said barrier is composed of an insulating material.

10. The system of claim 7 wherein said barrier is composed of a combination of metal and insulating material.

11. The system of claim 7 wherein said heat recovery system is a gas turbine heat waste heat recovery system and said inlet for the acceptance of heat input provides for the acceptance of exhaust gases from a gas turbine engine.

12. An integrated waste heat recovery system comprising: a shared upper drum;a heat recovery section having a first lower drum, an inlet, an outlet, and a plurality of boiler tubes which connect said upper drum and said first lower drum;a conventional boiler section having a second lower drum, an inlet, an outlet, a plurality of boiler tubes which connect said upper drum and said second lower drum, and a combustion chamber defined by a portion of said plurality of boiler tubes;a barrier between said plurality of boiler tubes in said heat recovery section and said plurality of boiler tubes in said conventional section whereby heat transfer between said sections is restricted.

13. The system of claim 12 wherein said barrier is composed of metal.

14. The system of claim 12 wherein said barrier is composed of an insulating material.

15. The system of claim 12 wherein said barrier is composed of a combination of metal and insulating material.

16. The system of claim 12 wherein said heat recovery system is a gas turbine heat waste heat recovery system and said inlet for the acceptance of heat input provides for the acceptance of exhaust gases from a gas turbine engine.