RU2793269C1 - Regasification and gas heater unit - Google Patents

Abstract

FIELD: heat engineering.

SUBSTANCE: invention can be used for regasification of liquefied hydrocarbon gases, liquid hydrogen and other cryogenic liquids. The regasification and gas heater unit contains a housing with heat-receiving elements, consisting of two pipes - external with a plugged end and internal with an open end, forming, respectively, external outlet and internal et channels, a regasified liquid supply line, a gas outlet line to the consumer, a coolant outlet line from the body. The housing contains a coolant inlet line inside the housing with a coolant flow controller and a coolant temperature sensor. Heat-receiving elements are combined into modules. Each module includes one or more heat-receiving elements and is connected through a shut-off valve to the regasified liquid supply line through the internal input channels of the heat-receiving elements of this module, and through the external output channels of the heat-receiving elements - to the gas outlet line to the consumer.

EFFECT: increasing the reliability of the liquid gasification process, simplifying the design, and also ensuring safe operation.

7 cl, 5 dwg

Description

The invention relates to the field of heat engineering and can be used for regasification of liquefied hydrocarbon gases, liquid hydrogen and other cryogenic liquids coming from stationary storages (hubs) and mobile tanks and gas supply to the consumer in a wide range of costs.

A cryogenic liquid evaporator is known (RF patent No. 2347972, IPC F17C 9/02, publ. 27.02.2009), containing a housing made in the form of two-layer cylindrical shells forming an annular cavity for the passage of a heating coolant, each of the shells consists of two rigidly connected between cylinders, between which channels are formed, combined into manifolds for supplying and manifolds for withdrawing a cryogenic product, while at the inlet to the annular cavity a cover is fixed, in which mixing elements and an igniter are installed, and a gas conduit is fixed at the outlet. This cryogenic liquid evaporator contains heat exchangers, the channels of which are formed by two-layer cylindrical shells, and when the liquid is heated and evaporated in the flow, crisis phenomena will occur, accompanied by cavitation and unstable flow regimes of the vapor-liquid medium when the load changes.

A technological heater is known (RF patent No. 2467260, IPC F24H 3/00, publ. 11/20/2012), containing a burner, a shell-and-tube heat exchanger having an outer belt of heat exchange pipes and at least one internal belt of heat exchange pipes, a chimney, collectors inlet and outlet of the heated medium, each heat exchange pipe is a set of two pipes - external with a blind end and internal with an open end, respectively facing the burner, forming an external and internal cavities, while the outer cavity is in communication with the inlet manifold, and the inner a cavity with a collector for the outlet of the heated medium. Inside the shell-and-tube heat exchanger in its upper part there is at least one ceiling section of heat exchange tubes located along the entire length of the heat exchanger or along its part. The heat transfer intensifiers are made in the form of stampings on the walls of the heat exchange tubes, or in the form of a twisted tape on the walls of the heat exchange tube, or in the form of corrugations. The known device is ineffective for liquid regasification, since the hydraulic paths of the heat exchange pipe, consisting of two pipes, form internal and external channels with a constant flow area. Due to the evaporation of the liquid in the channel tract, a two-phase flow with various structural forms (bubble, disperse, film, and others) will be realized, which in turn will lead to numerous crisis phenomena: heat transfer crisis, cavitation, flow crisis. These phenomena will hinder the safe and manageable operation of the device.

A liquefied hydrocarbon gas evaporator is known (RF patent No. 2597633, IPC F17C9/02, publ. 09/10/2016), containing a housing filled with a liquid intermediate heat carrier, a hollow shell with a blind outlet end mounted on the housing axis. In the inner cavity of the shell there is a pipeline for supplying liquefied hydrocarbon gas, on the cylindrical surface of which rows of radial holes are made, and its outlet end is made deaf. The evaporator also contains an annular combustion chamber with a burner, an ignition device located on the cylindrical surface of the annular combustion chamber, tubular heat exchange elements located around the shell and connecting the internal cavity of the annular combustion chamber with a chimney located in the outlet part of the housing. This LPG evaporator does not allow operation in a wide range of gas consumption changes and contains a burner device, which increases its fire hazard.

A gas regasifier-heater is known (RF patent No. 2708479, IPC F17C9 / 00. publ. 09.12.2019), the closest in technical essence and adopted as a prototype, containing a burner, a chimney, a heat exchanger-heater, consisting of two pipes - external with a deaf end and an internal one with an open end, respectively facing the burner device, and forming external and internal channels. The inner channel is connected with the supply line of the regasified liquid, and the outer channel is connected with the outlet branch pipe. The heat exchanger-evaporator consists of two pipes - external with a blind end and internal with an open end, and forming external and internal channels, while the external channel of the heat exchanger-evaporator is connected to the gas outlet line, and the outlet branch pipe of the heat exchanger-heater is connected through a throttle device with an internal channel of the heat exchanger-evaporator. In this gas regasifier-heater, heat is transferred to the heat exchangers by fire heating of the heat exchangers, which complicates its safe operation. In addition, the separate placement of the throttle device and the heat exchanger-evaporator complicates the design and leads to an increase in hydraulic losses along the path of the regasifier-heat exchanger.

The technical problem to be solved by the present invention is to create a gas regasifier-heater that provides a safe and controlled regasification process, enhanced functionality and design versatility.

The technical result to be achieved by the present invention is to increase the reliability of the process of gasification of liquids, to simplify the design through the use of modules with the same type of heat-receiving elements. use, ensuring the stable operation of the regasifier-heater in the mode of variable loads, as well as ensuring safe operation through the use of an intermediate heat carrier instead of burners.

The technical result is achieved by the fact that in an installation for regasification of liquefied gas, containing a container with liquefied gas, a filling line, an inlet manifold, a housing in which modules are installed containing a different number of the same type of heat-receiving elements (TV elements), with the possibility of combining options for including modules in the process regasification, outlet header, coolant supply line with flow controller, what is new is that the gas regasifier-heater contains a housing in which modules containing fuel elements are enclosed with the possibility of combining options for switching on modules in which heating and evaporation of liquefied gas occurs due to the heat transferred from the intermediate coolant located in the housing.

TVEL contains inner and outer channels with a throttle device at the outlet of the inner tube.

TVEL contains a swirling device - a blade swirler in the area of the annulus channel (between the inner and outer channel).

Heat exchange intensifiers are located on the outer surface of the inner tube of the fuel element.

The inner tube of the TVEL contains at least one nozzle (throttle) channel.

The external channel of the TVEL is made with a discretely changing flow area.

The external channel of the TVEL is made with a smoothly changing flow area.

The coolant supply line contains a flow controller.

The gas regasifier-heater is equipped with means for measuring the temperature, pressure and flow of working fluids (regasified liquid, liquid vapor and coolant) and a control system for the characteristics of the regasification process.

The essence of the gas regasifier-heater is as follows: liquid intake from the tank and its supply with increasing pressure to the inlet collector; supplying liquefied gas to a heat exchanger containing a heater and an evaporator and consisting of a housing with at least 3 fuel rod modules (1 TVEL, 2 TVEL, 4 TVEL); swirling of the liquid flow is carried out in the regasifier-heater using a swirler; supplying energy to the fluid flow in the heat-receiving element and heating it to a temperature not exceeding the saturation temperature, which corresponds to the fluid pressure at the inlet to the heat-receiving element; fluid supply to the throttle device; adiabatic expansion of the heated medium in the throttle channel with the formation of a two-phase flow; swirling of the two-phase flow in the outer channel of the heat-receiving element; supply of energy to a two-phase flow until the liquid phase evaporates and heating the gas flow to a given temperature, which leads to an increase in the reliability and efficiency of the process of regasification of cryogenic liquids and stable operation of heat exchangers without boiling crises, heat transfer in its hydraulic path.

In FIG. 1 shows the technological scheme of the gas regasifier-heater.

In FIG. 2 shows a heat-receiving element (TVEL) with constant areas of hydraulic paths, containing a bladed swirler.

In FIG. 3 shows a heat-receiving element (TVEL) with constant areas of hydraulic paths, containing a helical heat transfer intensifier.

In FIG. 4 shows a heat-receiving element (TVEL) with a discretely changing area of the hydraulic path,

In FIG. 5 shows a heat-receiving element (TVEL) with a smoothly changing area of the hydraulic path.

Here: 1 - capacity; 2 - refueling line; 3 - pump; 4 - collector; 5 - body; 6 - cover; 7 - heat-receiving element (TVEL); 8 - module containing one TVEL; 9 - module containing two fuel rods; 10 - module containing four fuel rods; 11 - receiver, 12 - gas outlet line, 13 - coolant inlet line, 14 - coolant outlet line, 15 - control unit, 16 - external pipe, 17 - inlet pipe, 18 - outlet pipe, 19 - internal pipe, 20 - plug , 21 - nozzle block, 22 - nozzle, 23 - vane swirler (pylon), 24 - helical heat transfer intensifier, 25 - intermediate pipe 26 - adapter, 27 - conical pipe, (B ₁ , B ₂ , B ₃ , B ₄ , B ₅ , B ₆ ) - shut-off valves, (KEO ₁ , KEO ₂ , KEO ₃ ) - shut-off valves, (PSK ₁ , PSK ₂ ) - safety valves, (C ₁ , C ₂ ) - candles. (R ₀ , R ₁ , R ₂ ) - pressure sensors, (T ₀ , T ₁ , T ₂ , T ₃ ) - temperature sensors, (KZ ₁ ) - shut-off valve, (RD ₁ ) - reducer, G - regulator- flow sensor, G _T - coolant flow controller

The gas regasifier-heater contains a container 1 in which liquefied gas is placed. Tank 1 is equipped with a filling line 2, a pressure sensor P ₀ , a safety valve PSK-1, a candle C-1, a temperature sensor T ₀ , shut-off valves B-1, B-2, B-3. Tank 1 is connected by a pipeline to manifold 4. In the pipeline connecting tank 1 to manifold 4, the following are installed: a shut-off valve B6, a bypass line with pump 3 and shut-off valves V-4, V-5, a regulator-flow sensor G. Collector 4 is equipped with a sensor temperature T ₁ and pressure sensor P ₁ . Collector 4 is connected by individual pipelines to one or more modules, which include one or more heat-receiving elements (REs) 7. FIG. 1 shows three modules: module 8 containing one fuel element, module 9 containing two fuel elements, module 10 containing four fuel elements. The number of fuel elements in a module is determined by the expression: where n is the number of fuel elements in a module, i is the serial number of the module. Controlled shut-off valves are installed in the pipeline connecting collector 4 with each of the modules. For example, for a modular regasifier-heater containing three modules, this is a shut-off valve KEO ₁ , before module 8, a shut-off valve KEO ₂ , before module 9, a shut-off valve KEO ₃ , before module 10. Shut-off or shut-off valves can be used as shut-off valves valves with pneumatic, electric and mechanical control types. The modules are mounted on cover 6 and placed in housing 5, through which the coolant is pumped. Housing 5 contains a coolant inlet line 13 with a coolant flow controller G _T , a coolant temperature sensor T _T and a coolant outlet line 14. The gas regasifier-heater is equipped with a control unit 15, which receives measurement information from temperature, pressure and flow sensors. Temperature, pressure and flow sensors have the ability to generate an electrical output signal. The control unit 15 manages and controls the parameters of the regasification process (temperature, pressure and flow of working fluids) and allows you to transfer information to a higher level and receive and execute control commands

Fuel rods 7, of which the modules are made, are made according to the scheme of the Field tube (pipe in a pipe) and can have various design options: fuel rod with constant areas of hydraulic paths, containing a vaned swirler (Fig. 2); TVEL with constant areas of hydraulic paths, containing a spiral heat transfer intensifier (Fig. 3); TVEL with a discretely changing area of the hydraulic path, (Fig. 4); TVEL with a smoothly changing area of the hydraulic path (Fig. 5).

TVEL with constant areas of hydraulic paths (Fig. 2) contains an inlet pipe 17, which is connected to the inner pipe 19. The pipe 19 is placed in the outer pipe 16. The outer pipe contains a plug 20 and an outlet pipe 18. The outlet pipe 18 is connected tangentially to the outer pipe 16 . On the inner pipe 19, on the side opposite from the inlet, there is a block of nozzles 21 containing one or more nozzles 22. The channel of the nozzle (nozzles) is oriented in such a way as to give the flow both tangential and axial components of the flow velocity flowing from the nozzles. In the annular channel between the outer 16 and inner 19 pipes there is a blade swirler 23, which swirls the flow, ensures the stability of the structure, and at the same time is a thermal bridge between the outer 16 and inner 19 pipes.

TVEL with constant areas of hydraulic paths, containing a spiral heat transfer intensifier (Fig. 3), is similar in design to the TVEL shown in Fig. 2. The differences lie in the fact that the TVEL (Fig. 3) does not have a bladed swirler, and a helical heat transfer intensifier 24 is mounted on the inner surface of the outer pipe 16. The heat transfer intensifier 24 is made of a tube or rod. The heat transfer intensifier 24 is mounted in such a way that reliable thermal contact with the outer pipe 16 is ensured, for example, by soldering or welding.

TVEL with a discretely changing area of the hydraulic path (Fig. 4), contains an inlet pipe 17, which is connected to the inner pipe 19. On the inner pipe 19, on the side opposite from the inlet, a nozzle block 21 is installed, containing one or more nozzles 22. The pipe 19 is placed into the outer shell, which consists of an intermediate pipe 25 with a plug 20, an adapter 26 and an outer pipe 16 with an outlet pipe 18. Thus, the TVEL hydraulic path (Fig. 4) is a channel with a discretely variable area of the hydraulic path. 16. A helical heat transfer intensifier 24 is mounted on the inner surface of the outer pipe 16. A blade swirler (pylon) 23 is mounted on the inner pipe, which swirls the flow, ensures structural stability, and at the same time is a thermal bridge between the inner pipe 19 and the intermediate pipe 25.

TVEL with a smoothly changing area of the hydraulic path (Fig. 5) contains an internal pipe 19 with an inlet pipe 17, a nozzle block 21 and nozzles 22, similar to the design of TVELs (Fig. 2, 3). The internal pipe 19 of the fuel element with a smoothly changing area of the hydraulic path (Fig. 5) is placed in the outer shell, which consists of an outer pipe, a conical pipe 27 with a plug 20. The outer pipe contains an outlet pipe 18, which is attached (welded) to the pipe 16 tangentially. The hydraulic path of the TVEL (Fig. 5), formed by the inner tube 19 and the conical tube, is a channel with a smoothly changing area of the hydraulic path. A bladed swirler (pylon) 23 is mounted on the inner pipe, which swirls the flow, ensures the stability of the structure, and at the same time is a thermal bridge between the inner pipe 19 and the conical pipe 27.

The outlet pipes 18 of the fuel rods (Fig. 2, Fig. 3, Fig. 4, Fig. 5) are connected by pipelines to the receiver 11. In the pipeline in front of the receiver 11, a reducer RD-1, a shut-off valve KZ ₁ and a safety valve PSK ₂ with candle C are installed ₂ . The receiver is equipped with a pressure sensor P ₂ and a temperature sensor T ₂ . The receiver 11 contains the output line 12.

The gas regasifier-heater works as follows. Before starting work, tank 1 is filled with liquefied gas through the filling line 2 with valves B ₁ and B ₂ open and valve B ₃ closed to a volume not exceeding 85% of the nominal volume of the tank and the formation of a vapor cushion. The temperature and pressure of the liquid in container 1 are measured by sensors Р ₀ and Т ₀ . The cavity of the body 5, in which modules with fuel elements 7 are placed, is filled with a coolant. To ensure the safe operation of the gas regasifier-heater, tank 1 is equipped with a safety valve PSK-1, which opens when the pressure in the tank exceeds the maximum allowable pressure. Gas from the safety valve enters the spark plug C-1.

To carry out the regasification process, valve B ₁ closes and valve B ₃ opens. At the same time, the coolant is circulated through the cavity of the housing 5, having a certain temperature T ₃ ≥T ₂ , where T ₂ is the temperature in the receiver, set by the gas consumer. The following can be used as a heat carrier: water of natural reservoirs (rivers, lakes, seas); liquids circulating in the cooling systems of power plants and other heated liquids (low-potential heat sources). From container 1, liquid through open valves B ₂ and B ₃ enters manifold 4. Liquid is supplied to manifold 4 either by force using pump 3 with valve B ₆ closed and valves B ₄ and B ₅ open, or by self-displacement with valves B ₄ closed and B ₅ and an open valve B ₆ , under vapor pressure in a gas cushion, with valves B ₄ and B ₅ closed and valve B ₆ open. The pressure and temperature of the liquid in the manifold 4 are measured by sensors P ₁ and T ₁ . From the collector 4, the liquid enters one or more modules through shut-off valves (KEO ₁ , KEO ₂ , KEO ₃ ) to fuel elements 7. The combination of the “open-closed” position of the shut-off valves (KEO ₁ , KEO ₂ , KEO ₃ ) allows you to discretely control the flow liquid supplied for regasification, a multiple of the flow rate through a single fuel element, corresponding to the flow rate 1S (here S is taken as a conventional unit). For example, when the shut-off valve KEO ₁ is open and the shut-off valves KEO ₂ , KEO ₃ are closed, the performance of the regasifier - modular gas heater is 1G, with the shut-off valve KEO ₂ open and the valves KEO ₁ and KEO ₃ closed, the performance will be 2S, with open valves KEO ₁ , KEO ₂ and closed valve KEO ₃ performance will be 3S. According to the three-module scheme shown in FIG. 1, the combination of the "open-closed" position of the shut-off valves KEO ₁ , KEO ₂ , KEO3 provides a discrete change in the regasifier performance from 1S to 7S. When using more modules, the discrete capacity control range can be any given value. Along with discrete capacity control, smooth capacity control is possible using the flow sensor G. Since the consumer's gas needs are subject to significant load fluctuations (seasonal, daily, and in mobile power plants and instantaneous), discrete and smooth control of gas supply over a wide range of flow rates and the possibility of dynamic control of the regasification process increases the reliability of the regasifier and expands its functionality. The modular principle of building a regasifier and equipping the modules with the same type of fuel rods unifies and simplifies the design of the regasifier.

The liquid enters the fuel elements through the inlet pipe 17, through the inner pipe 19 is sent to the nozzle block 21 and then to the nozzle 22 (Fig. 2, 3,4,5). In the nozzles 22, the liquid is throttled, accompanied by its atomization, partial evaporation and the formation of a dispersed vapor-liquid flow behind the nozzles 22, in which the carrier medium is steam with liquid drops dispersed in it (Deich M.E., Filippov G.A. Gas dynamics of two-phase media. - M .: Energoizdat, 1981. p. 391). A necessary and sufficient condition for the formation of a two-phase flow at the outlet of the injectors 22 is the fulfillment of the requirement: the pressure in the cavity of the fuel rod between the inner pipe 19 and the outer pipe 16 must be less than or equal to the saturation pressure corresponding to the liquid temperature T ₀ (liquid temperature in tank 1). The value of this pressure is controlled by the sensor R ₂ installed in the receiver 11 (Fig. 1). The operating mode of the regasifier is set in such a way that P ₂ <Ps(T ₀ ), where Ps(T ₀ ) is the saturated vapor pressure of the regasified liquid at temperature T ₀ .

The nozzles 22 in the nozzle block 21 are oriented in such a way as to give the flow velocity flowing into the cavity of the fuel element between the outer pipe 16 and the inner pipe 19, both tangential and axial components of the flow rate. Additional swirling of the flow in the cavity of the fuel element is provided by a bladed swirler 23 installed between the outer pipe 16 and the inner pipe 19 (Fig. 2), the swirler 23 installed between the intermediate tube 25 and the inner pipe 19 (Fig. 4), the swirler 23 installed between the pipe conical 27 and an internal pipe 19 (Fig. 5) and a spiral heat transfer intensifier 24 installed on the inner wall of the outer pipe 16 (Fig. 3, 4)

The flow swirling contributes to the high perfection of heat and mass transfer processes in fuel rods (Fig. 2,3,4,5). This is due to the drift of the liquid (heavy) phase in a swirling vapor-liquid flow to the inner walls of the hydraulic path of the TVEL (the inner walls of the external pipe 16, the intermediate pipe 25, the conical pipe 27). As a result of the action of mass forces, the walls will be irrigated and a liquid film will form on the channel walls. The presence of liquid on the channel wall in the form of a film or its fragments ensures high heat transfer coefficients compared to the gaseous medium. (G.A. Mukhachev, V.K. Shchukin. Thermodynamics and heat transfer. Textbook for aviation universities. M .: Higher school. 1991, pp. 437-441). A similar function, improving heat transfer conditions, is performed by a helical heat transfer intensifier 24 installed on the inner wall of the outer pipe 16 in fuel rods (Fig. 3 and 4). Along with flow swirling, the spiral heat transfer intensifier increases the heat transfer surface and turbulizes the flow, which increases the heat flow from the wall to the heated medium.

In the regasifier gas heater, heat is transferred from the coolant, washing the fuel rods from the outside, to the regasified liquid entering the fuel rods. As heat is applied to the liquid, it evaporates. The resulting steam (gas) is heated to a predetermined temperature and enters the outlet pipe 18 (Fig. 2, 3, 4, 5). The tangential connection of the outlet branch pipe with the external pipe helps to maintain the tangential component of the flow velocity in the hydraulic cycle of the fuel element and intensifies the heat transfer processes. The gas heated in the fuel rods enters the receiver 11 through the outlet pipes 18 through pipelines (Fig. 1). From the receiver 11, the gas enters the consumer's line 12. In the pipeline in front of the receiver 11, a reducer RD ₁ and a safety valve PSK ₂ are installed. Reducer RD ₁ is designed to stabilize the pressure in the receiver 11 and consumer line. The safety valve PSK ₂ ensures the safe operation of the regasifier and is activated when the maximum allowable pressure in the receiver 11 is reached, in case of excess pressure and to maintain the specified gas pressure in the receiver 11 in the T ₂ pipeline.

From the receiver 11, steam enters the gas outlet line 12. The temperature and pressure of the steam supplied to the consumer are regulated by the control unit 15 using a controlled supply of coolant using a coolant flow and temperature regulator, the regulation of the flow of steam supplied to the consumer is provided (discretely) by a combination of connected to the receiver of modules and smoothly with the regulator-flow sensor G.

Claims (7)

1. Gas regasifier-heater, containing a housing with heat-receiving elements, consisting of two pipes - external with a plugged end and internal with an open end, forming, respectively, external - outlet and internal - inlet channels, a regasified liquid supply line, a gas outlet line to the consumer, coolant exit line from the housing, characterized in that the housing contains a coolant inlet line inside the housing with a coolant flow controller and a coolant temperature sensor, heat-receiving elements are combined into modules, each module includes one or more heat-receiving elements, each module through a cut-off the valve is connected to the supply line of the regasified liquid through the internal input channels of the heat-receiving elements of this module, and through the external output channels of the heat-receiving elements, each module is connected to the gas outlet line to the consumer. 2. Gas regasifier-heater according to claim 1, characterized in that a receiver equipped with a pressure sensor and a temperature sensor is installed in the gas outlet line to the consumer, in addition, a reducer, a shut-off valve and a safety valve are installed in front of the receiver. 3. Gas regasifier-heater according to claim 1, characterized in that the heat-receiving elements that make up the modules are made according to the pipe-in-pipe scheme, each heat-receiving element contains an inlet pipe connected to the inner pipe, which is placed in the outer pipe with a plugged end and having an outlet branch pipe connected to it tangentially, on the inner pipe from the side opposite from the inlet, a nozzle block is installed containing one or more nozzles, while the nozzle channels are oriented both tangentially and along the axial component of the flow velocity flowing from the nozzles. 4. Gas regasifier-heater according to claim 1, characterized in that a blade swirler is installed in the annular channel between the outer and inner pipes of the heat-receiving element. 5. Gas regasifier-heater according to claim 1, characterized in that on the inner surface of the outer tube of the heat-receiving element, a spiral-shaped heat transfer intensifier made of a tube or rod is mounted. 6. Gas regasifier-heater according to claim 1, characterized in that the heat-receiving element is made with a discretely variable area of the hydraulic path or with a smoothly changing area of the hydraulic path. 7. Gas regasifier-heater according to claim 1, characterized in that it has a control unit, which receives measurement information from temperature, pressure and flow sensors.

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