BR-112022019574-B1 - Hermetically sealed and integrated turboexpander generator and thermodynamic system.

BR112022019574B1BR 112022019574 B1BR112022019574 B1BR 112022019574B1BR-112022019574-B1

Abstract

HERMETICALLY SEALED AND INTEGRATED TURBO-EXPANDER-GENERATOR WITH SUSPENDED TURBOMACHINE. This is a hermetically sealed and integrated turbo-expander-generator (21) comprising a hermetically sealed housing arrangement (23), a turbo-expander (25), a compressor (27) and an electric generator (29), arranged in the hermetically sealed housing arrangement (23) along a common drive shaft line (31), supported by active magnetic bearings. A thermodynamic system (1) is also disclosed that uses the hermetically sealed and integrated turbo-expander-generator (21) to convert waste heat from a waste heat source (7) into electrical energy. One of the turbo-expander and the compressor comprises two sections arranged in a suspended configuration at the ends of the common drive shaft line.

Inventors

Francesco CANGIOLI
Davide BILIOTTI
Massimiliano ORTIZ NERI
Giuseppe Sassanelli
Vittorio Michelassi

Assignees

Nuovo Pignone Tecnologie - S.r.l

Dates

Publication Date: 20260310
Application Date: 20210319
Priority Date: 20200331

Claims (15)

1. Hermetically sealed and integrated turbo-expander-generator (21) comprising: a hermetically sealed housing arrangement (23; 23.1, 23.2); a turbo-expander (25; 25.1, 25.2) arranged in the hermetically sealed housing arrangement; a fluid pressurization turbomachine (27; 27.1, 27.2), arranged in the hermetically sealed housing arrangement (23; 23.1, 23.2); an electric generator (29) arranged in a hermetically sealed housing arrangement (23; 23.1, 23.2); wherein: the turboexpander (25; 25.1, 25.2), the fluid pressurization turbomachine (27; 27.1, 27.2) and the electric generator (29) are arranged in a common drive shaft line (31; 31.1, 31.2), comprising at least one drive shaft rotatably supported by active magnetic bearings (41, 41.1-41.5) in a hermetically sealed housing arrangement (23; 23.1, 23.2); at least one of the turboexpander (25; 25.1, 25.2) and the fluid pressurization turbomachine (27; 27.1, 27.2) is arranged between the bearings; characterized by the other of the turboexpander (25; 25.1, 25.2) and the fluid pressurization turbomachine (27; 27.1, 27.2) comprise a high-pressure machine section (25.1, 27.2) and a low-pressure machine section (25.2), fluidly coupled sequentially and arranged in a suspended configuration at a first end of the drive shaft line (31; 31.1, 31.2) and at a second end of the drive shaft line (31; 31.1, 31.2), respectively; and the electric generator (29) and the other between said turboexpander (25; 25.1, 25.2) and said fluid pressurization turbomachine (27; 27.1, 27.2) is disposed between the high pressure machine section (25.1, 27.2) and the low pressure machine section (25.2; 27.1).
2. Turboexpander-generator (21), according to claim 1, the turboexpander being characterized in that it has a high-pressure turboexpander section (25.1) suspended at the first end of the drive shaft line (31; 31.1, 31.2) and a low-pressure turboexpander section (25.2) suspended at the second end of the drive shaft line (31; 31.1, 31.2); and wherein the electric generator (29) and the fluid pressurization turbomachine (27; 27.1, 27.2) are disposed between the high-pressure turboexpander section (25.1) and the low-pressure turboexpander section (25.2).
3. Turboexpander-generator (21), according to claim 2, characterized in that the electric generator (29) is disposed between the low-pressure turboexpander section (25.2) and the fluid pressurization turbomachine (27; 27.1, 27.2).
4. Turbo-expander-generator (21), according to claim 2 or 3, characterized by a joint (51) being provided between the electric generator (29) and the fluid pressurization turbomachine (27; 27.1, 27.2).
5. Turboexpander-generator (21), according to claim 1, characterized in that the fluid pressurization turbomachine has a low-pressure section (27.1) suspended at the first end of the drive shaft line (31; 31.1, 31.2) and a high-pressure section (27.2) suspended at the second end of the drive shaft line (31; 31.1, 31.2); and wherein the electric generator (29) and the turboexpander (25; 25.1, 25.2) are disposed between the low-pressure section (27.1) and the high-pressure section (27.2) of the fluid pressurization turbomachine.
6. Turboexpander-generator (21), according to claim 5, characterized in that the electric generator (29) is disposed between the low pressure section (27.1) of the fluid pressurization turbomachine and the turboexpander (25; 25.1, 25.2).
7. Turboexpander-generator (21), according to claim 5 or 6, characterized in that the turboexpander (25; 25.1, 25.2) is arranged along the drive shaft line (31; 31.1, 31.2) with a gas inlet end facing a section of the fluid pressurization turbomachine (27; 27.1, 27.2) and a gas outlet end facing the electric generator (29).
8. Turbo-expander-generator (21), according to claim 5 or 6 or 7, characterized in that a joint (51) is disposed between the electric generator (29) and the turbo-expander (25; 25.1, 25.2).
9. Turboexpander-generator (21), according to one or more of the preceding claims, characterized in that the fluid pressurization turbomachine (27; 27.1, 27.2) is one between a compressor and a pump.
10. Turboexpander-generator (21), according to one or more of the preceding claims, characterized in that the fluid pressurization turbomachine (27; 27.1, 27.2) is a multi-section turbomachine, comprising at least two sections (27.1, 27.2).
11. Turboexpander-generator (21), according to claim 10, characterized in that the multi-section fluid pressurization turbomachine (27.1, 27.2) is a turbomachine subjected to intercooling.
12. Turboexpander-generator (21), according to one or more of the preceding claims, the turboexpander (25; 25.1, 25.2) being characterized in that it is a multi-section turboexpander, comprising at least two sections (25.1, 25.2).
13. Turboexpander-generator (21), according to claim 12, characterized in that the multi-section turboexpander (25; 25.1, 25.2) is a reheated turboexpander.
14. Turbo-expander-generator (21), according to one or more of the preceding claims, characterized in that the electric generator (29) is disposed between the bearings (41, 41.1-41.5).
15. Thermodynamic system characterized by comprising: a waste heat source (7), adapted to transfer heat to a processed working fluid via an integrated turboexpander-generator (21) as defined in one or more of the preceding claims, wherein the turboexpander-generator is adapted to convert part of the waste heat into electrical energy.

Description

FIELD OF THE INVENTION [0001] Integrated turbomachines are disclosed in the present invention. More specifically, the embodiments of the present disclosure relate to combined turbomachines and generators adapted to convert thermal energy into electrical energy. [0002] The present disclosure also relates to thermodynamic systems, including turbomachinery and waste heat recovery generators. BACKGROUND OF THE INVENTION [0003] Several industrial processes produce a large amount of waste heat. Typical examples of waste heat generation processes are industrial processes for the production of steel, glass, and cement. Other examples are thermodynamic processes for the generation of mechanical or electrical energy by converting the thermal power generated by fuel combustion. Typically, fuel-based power generation processes convert less than 45% of the thermal energy generated by combustion into useful electrical or mechanical energy. Exhaust flue gas temperatures typically range between 300 °C and 700 °C, and the exhaust thermal energy can be worth several MW (megawatts). The heat contained in the exhaust flue gas is discharged into the environment and wasted. This has a serious environmental impact. [0004] Systems already exist that allow capturing some of the waste heat and converting it into useful energy or using it as such, for example, for heating buildings. However, existing systems for converting some of the waste heat into useful electrical or mechanical energy are complex and expensive, require a large footprint, and are demanding in terms of operating costs. They may also underperform under conditions not foreseen in the design. [0005] Therefore, there is a need for machines and systems that overcome or alleviate one or more of the disadvantages of the systems of current technology mentioned above. DESCRIPTION OF THE INVENTION [0006] Here is disclosed a hermetically sealed, integrated turbo-expander-generator comprising a hermetically sealed housing arrangement in which are disposed a turbo-expander, a fluid pressurization turbomachine and an electric generator. The turbo-expander, the electric generator and the fluid pressurization turbomachine are mounted along the same drive shaft line so that they rotate at the same speed. One of the turbo-expander and the fluid pressurization machine comprises a low-pressure section and a high-pressure section fluidly coupled to each other and disposed at opposite ends of the drive shaft line in a suspended configuration. [0007] The innovative arrangement reduces the thermal load on the electric generator and provides high energy efficiency for the combined rotating machine. [0008] As used herein, a fluid pressurization turbomachine is a turbomachine adapted to pressurize the working fluid flowing through the integrated machine. If the fluid is in a liquid state, the fluid pressurization turbomachine includes a pump. If the fluid is in a gaseous state, the fluid pressurization turbomachine includes a compressor. The nature of the fluid pressurization turbomachine used depends primarily on the type of thermodynamic cycle in which the hermetically sealed, integrated turboexpander-generator is used. Generally, the fluid pressurization turbomachine comprises a compressor, since Brayton cycles or other cycles that do not involve a phase change of the working fluid are preferably involved in waste heat recovery. However, the possibility of using a Rankine cycle or other cycles that involve a phase change in the working fluid is not excluded. In such a case, the fluid pressurization turbomachine usually includes a pump. [0009] As used herein, a hermetically sealed housing arrangement may include a single housing which contains the three rotating machines mentioned above, with a common drive shaft extending through them. Rotating seals may be provided along the drive shaft to prevent leakage from one rotating machine to another, for example, to separate the cooling gas of the electric generator from the working fluid processed through the turboexpander and the fluid pressurization turbomachine. However, no rotating part of the machine is exposed outside the housing arrangement so that leakage to the environment is prevented. [0010] The hermetically sealed housing arrangement may also include, however, two or more housings, each of which is hermetically sealed and houses one or two of the rotating machines mentioned above, namely, the turboexpander, the fluid pressurization turbomachine and the electric generator. In this case, the torque is transmitted from one housing to the other via a magnetic joint, so that, also in this case, no rotating mechanical part is exposed to the outside of the housing arrangement, which remains hermetically sealed as a whole. [0011] As used herein, a common drive shaft line may consist of a single drive shaft or of drive shaft line portions, i.e., separate drive shafts, which are coupled to each other physically by a joint, such as a flexible