1. The starting system of the small radial flow turboexpander is characterized by comprising an air inlet main pipe, a main pipeline, a bypass pipeline, a detection device and a control device;

one end of the air inlet main pipe is a medium gas inlet, the other end of the air inlet main pipe is respectively communicated with one end of the main path pipeline and one end of the bypass pipeline, the other end of the main path pipeline is communicated with an inlet of the small-sized runoff turbo expander, and the other end of the bypass pipeline is communicated with an outlet of the small-sized runoff turbo expander;

the main pipeline is provided with a regulating quick-closing valve, and the bypass pipeline is provided with a bypass regulating valve;

the detection device is used for detecting the air inlet pressure of the air inlet main pipe and the rotating speed of the small radial flow turboexpander in real time;

the control device is used for receiving the external air inlet pressure of the air inlet main pipe and setting the rotating speed of the small-sized radial flow turboexpander, receiving valve state signals fed back by the adjusting quick-closing valve and the bypass adjusting valve and detection results sent by the detection device, and controlling the opening degree of the adjusting quick-closing valve and the opening degree of the bypass adjusting valve so that the small-sized radial flow turboexpander can operate at the set air inlet pressure and the set rotating speed.

2. The startup system of a compact radial flow turboexpander according to claim 1, wherein said detecting means includes a pressure transmitter for detecting an intake pressure of said intake manifold and a rotational speed transmitter for detecting a rotational speed of the compact radial flow turboexpander.

3. The startup system of a small radial flow turboexpander according to claim 1, wherein the control means includes a human machine interface component and a controller, the human machine interface component being connected to the controller.

4. The startup system of a small-scale radial flow turboexpander according to claim 1, wherein the small-scale radial flow turboexpander is a centrifugal turboexpander.

5. A method of starting a start-up system for a compact radial flow turboexpander according to claim 1, comprising the steps of:

a. starting the small-sized radial flow turboexpander, setting the inlet pressure of an inlet manifold to be P1 through the control device, setting P1= P0+ A, setting P0 to be the preset inlet pressure required by starting the small-sized radial flow turboexpander, wherein A is a constant and is more than or equal to 0 and less than or equal to 0.1 Mpa;

b. the control device controls the opening of the bypass regulating valve according to an intake pressure set value P1 and a measured value of the intake pressure so as to enable the intake pressure of the intake manifold to reach P1;

c. after the inlet pressure of the inlet manifold reaches P1, setting the rotation speed of the small-sized radial flow turboexpander to be V0 through the control device, wherein V0 is the preset warming-up rotation speed of the small-sized radial flow turboexpander;

d. the control device controls the opening of the regulating quick-closing valve according to the set rotating speed value V0 and the rotating speed measurement value of the small-sized radial flow turboexpander so that the rotating speed of the small-sized radial flow turboexpander reaches V0;

e. after the small-sized radial flow turboexpander runs at the rotating speed V0 for a preset time t, the inlet pressure of the inlet manifold is set to be P through the control device_{Forehead (forehead)}，P_{Forehead (forehead)}The rated inlet pressure of the small radial flow turbine expander is adopted;

f. the control device sets a value P according to the intake pressure_{Forehead (forehead)}And the measured value of the air inlet pressure controls the opening of the bypass regulating valve so as to ensure that the air inlet pressure of the air inlet main pipe reaches P_{Forehead (forehead)}；

g. The inlet pressure of the inlet manifold reaches P_{Forehead (forehead)}Then, the rotating speed of the small radial flow turboexpander is set to be V through the control device_{Forehead (forehead)}，V_{Forehead (forehead)}The rated rotating speed of the small radial flow turbine expander is adopted;

h. the control device is based on the set value V of the rotating speed_{Forehead (forehead)}And controlling the opening of the adjusting quick-closing valve according to the rotating speed measurement value of the small-sized radial flow turboexpander so as to enable the rotating speed of the small-sized radial flow turboexpander to reach V_{Forehead (forehead)}。

6. The method of starting up a startup system for a small radial flow turboexpander according to claim 5, wherein the regulating quick-closing valve is kept fully closed and the bypass regulating valve is kept fully open before starting up the small radial flow turboexpander, so that the medium passes entirely through the bypass line without entering the main line.

7. The starting method of the starting system of the small-sized radial flow turboexpander according to claim 5, characterized in that the intake pressure P0 required for starting the small-sized radial flow turboexpander and the warm-up rotation speed V0 of the small-sized radial flow turboexpander are obtained by a test comprising the steps of:

keeping the regulating quick-closing valve fully closed, keeping the bypass regulating valve fully opened, and enabling the medium to completely pass through the bypass pipeline without entering the main pipeline;

fully opening the regulating quick-closing valve;

and gradually reducing the opening degree of the bypass regulating valve to increase the air inlet pressure of the air inlet main pipe until the opening degree of the regulating quick-closing valve is kept unchanged after the small-sized radial flow turboexpander starts to rotate, recording the air inlet pressure value at the moment as the air inlet pressure P0 required by the start of the small-sized radial flow turboexpander, and recording the highest rotating speed which can be reached by the small-sized radial flow turboexpander as the warming rotating speed V0.

8. The starting method of the starting system of the small radial flow turboexpander according to claim 5, wherein in the step b, the control means performs PID control of the opening degree of the bypass regulating valve according to the deviation between the intake pressure set value P1 and the measured value of the intake pressure so that the intake pressure of the intake manifold reaches P1;

in the step d, the control device performs PID control on the opening of the regulating quick-closing valve according to the deviation between the rotating speed set value V0 and the rotating speed measured value of the small-sized radial flow turboexpander so as to enable the rotating speed of the small-sized radial flow turboexpander to reach V0;

in step f, the control device sets the value P according to the intake pressure_{Forehead (forehead)}Deviation from the measured value of the intake pressure performs PID control on the opening of the bypass regulating valve so that the intake pressure of the intake manifold reaches P_{Forehead (forehead)}；

In step h, the control device sets the value V according to the rotating speed_{Forehead (forehead)}And carrying out PID control on the opening of the regulating quick-closing valve by the deviation between the rotating speed measured value of the small-sized radial flow turboexpander and the rotating speed measured value of the small-sized radial flow turboexpander so as to enable the rotating speed of the small-sized radial flow turboexpander to reach V_{Forehead (forehead)}。

9. The starting method of the starting system of the small-sized radial flow turboexpander according to claim 5, wherein in any one of the steps a to h, if the measured value of the rotation speed of the small-sized radial flow turboexpander exceeds a preset upper rotation speed limit, the control device controls and adjusts the quick closing valve to be fully closed;

in the step h, the rotating speed of the small radial flow turboexpander reaches V_{Forehead (forehead)}In the process, the control device controls the opening of the adjusting quick-closing valve to gradually reduce the rotating speed increasing rate of the small radial flow turboexpander.

10. The method for starting up a small radial flow turboexpander starting system according to claim 5, wherein the predetermined time t satisfies: t is more than or equal to 3 minutes and less than or equal to 5 minutes.

Background

As a novel small-sized runoff turboexpander, the centrifugal turboexpander is rarely applied to domestic engineering, and the introduction of a starting system and a starting method of the centrifugal turboexpander is also very little. If a startup system and method similar to a large axial flow turbine is adopted, problems exist because: the centrifugal turbo expander is characterized in that the blades are short and small, the rotor mass is small, and under the condition of higher medium parameters, the rotating speed is easy to excessively fly up at the moment of starting, so that the starting stability of a unit is influenced; 2, a main steam valve and a regulating valve are arranged on an air inlet pipeline of a general steam turbine, and a long time of warming pipes and warming valves exists during startup, which is opposite to the concept that a centrifugal turbo expander needs to be started quickly; 3 when an emergency working condition such as overspeed occurs, the main steam valve and the regulating valve are quickly closed, but the main steam valve and the regulating valve are limited by the quick closing time and the leakage grade of the regulating valve, and a part of media between the main steam valve and the regulating valve still enters the steam turbine. Therefore, it is important to design a special starting system and method to ensure safe, reliable and fast starting of the centrifugal turboexpander.

Disclosure of Invention

The invention aims to provide a starting system and a starting method of a small-sized runoff turboexpander, which can realize the quick starting of the small-sized runoff turboexpander and ensure the safety and reliability of the starting process.

The starting system of the small radial flow turboexpander comprises an air inlet main pipe, a main pipeline, a bypass pipeline, a detection device and a control device; one end of the air inlet main pipe is a medium gas inlet, the other end of the air inlet main pipe is respectively communicated with one end of the main path pipeline and one end of the bypass pipeline, the other end of the main path pipeline is communicated with an inlet of the small-sized runoff turbo expander, and the other end of the bypass pipeline is communicated with an outlet of the small-sized runoff turbo expander; a main pipeline is provided with a regulating quick-closing valve, and a bypass pipeline is provided with a bypass regulating valve; the detection device is used for detecting the air inlet pressure of the air inlet main pipe and the rotating speed of the small radial flow turboexpander in real time; the control device is used for receiving the external air inlet pressure of an air inlet main pipe and setting the rotating speed of the small-sized radial flow turboexpander, receiving and adjusting valve state signals fed back by the quick-closing valve and the bypass adjusting valve and detection results sent by the detection device, and controlling and adjusting the opening degree of the quick-closing valve and the opening degree of the bypass adjusting valve so that the small-sized radial flow turboexpander can operate at the set air inlet pressure and the set rotating speed.

The starting method of the starting system of the small radial flow turboexpander comprises the following steps:

a. starting the small-sized radial flow turboexpander, setting the air inlet pressure of an air inlet main pipe to be P1, P1= P0+ A through a control device, wherein P0 is the air inlet pressure required by starting the preset small-sized radial flow turboexpander, A is a constant, and A is more than or equal to 0 and less than or equal to 0.3 Mpa;

b. the control device controls the opening of the bypass regulating valve according to the set value P1 of the intake pressure and the measured value of the intake pressure so as to enable the intake pressure of the intake manifold to reach P1;

c. after the inlet pressure of the inlet manifold reaches P1, setting the rotation speed of the small-sized radial flow turboexpander to be V0 through the control device, wherein V0 is the preset warming-up rotation speed of the small-sized radial flow turboexpander;

d. the control device controls the opening of the quick-closing valve according to the set rotating speed value V0 and the rotating speed measurement value of the small-sized radial flow turboexpander so that the rotating speed of the small-sized radial flow turboexpander reaches V0;

e. after the small radial flow turboexpander runs for a preset time t at the rotating speed V0, the inlet pressure of an inlet manifold is set to be P through a control device_{Forehead (forehead)}，P_{Forehead (forehead)}The rated inlet pressure of the small radial flow turbine expander is adopted;

f. the control device sets a value P according to the intake pressure_{Forehead (forehead)}And the measured value of the air inlet pressure controls the opening of the bypass regulating valve so as to ensure that the air inlet pressure of the air inlet main pipe reaches P_{Forehead (forehead)}；

g. The inlet pressure of the inlet manifold reaches P_{Forehead (forehead)}Then through the control deviceSetting the rotation speed of the small radial flow turboexpander to V_{Forehead (forehead)}，V_{Forehead (forehead)}The rated rotating speed of the small radial flow turbine expander is adopted;

h. the control device is based on the set value V of the rotating speed_{Forehead (forehead)}And controlling the opening of the quick-closing valve by using the rotating speed measurement value of the small-sized runoff turboexpander so as to enable the rotating speed of the small-sized runoff turboexpander to reach V_{Forehead (forehead)}。

The invention has at least the following advantages:

1. in the embodiment, a main pipeline adopts a regulating quick-closing valve to replace a main steam valve and a regulating valve arranged on an air inlet pipeline in the prior art, so that the number of valves and a pipeline connected between the regulating valve and the main steam valve in the prior art are reduced, the arrangement of the air inlet pipeline is simpler, the size of the whole machine is reduced, the time for warming the pipe and the valve can be shortened, and the starting speed of the small radial flow turboexpander is accelerated;

2. after the quick closing valve is adjusted to be quickly cut off, the gas quantity of the residual pipeline entering the small radial flow turboexpander is obviously reduced, the rotating speed can be ensured to be quickly reduced, and the safety of the starting process is improved;

3. compared with the starting mode of warming the valve and then warming the pipe in the prior art, the embodiment of the invention can finish the operations of warming the pipe, warming the valve and warming the pipe at one time during starting, thereby shortening the starting time;

4. the opening degrees of the regulating quick closing valve and the bypass regulating valve are controlled by the control device in the process from the start of the small radial flow turboexpander to the rising to the warming rotating speed, so that the stable rising speed can be ensured, and the rotating speed is not excessively raised;

5. the opening degree of adjusting the quick closing valve and the bypass regulating valve is controlled by the control device in the process that the small-size runoff turboexpander rises from the warm-up rotating speed to the rated rotating speed, the small-size runoff turboexpander can be guaranteed to rapidly and safely pass through a critical rotating speed area, and after the rated rotating speed is reached, the rotating speed overshoot is small and the fluctuation is small.

Drawings

Fig. 1 is a schematic diagram showing the construction of one embodiment of the start-up system of the small-sized radial flow turboexpander of the present invention.

Fig. 2 is a schematic diagram illustrating the control principle of an embodiment of the start-up system of the small-sized radial flow turboexpander according to the present invention.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

Please refer to fig. 1 and fig. 2. The starting system of the small radial flow turboexpander according to one embodiment of the invention comprises an air inlet manifold 11, a main pipeline 12, a bypass pipeline 13, a detection device and a control device.

One end of the air inlet main pipe 11 is a medium gas inlet, the other end of the air inlet main pipe 11 is communicated with one end of the main pipeline 12 and one end of the bypass pipeline 13 respectively, the other end of the main pipeline 12 is communicated with an inlet of the small-sized runoff turbo expander 7, and the other end of the bypass pipeline 13 is communicated with an outlet of the small-sized runoff turbo expander 7.

In the present embodiment, the small-sized radial flow turboexpander 7 is a centrifugal turboexpander. By "compact" is meant a radial flow turboexpander with a power output of 4Mw or less.

In the present embodiment, the centrifugal turboexpander 7 is connected to the generator 9 through the gear box 8. Wherein, the centrifugal turbo expander adopts a cantilever type structure to be installed on the gear box 8, and has compact integral structure and convenient arrangement.

The main pipeline 12 is provided with a regulating quick-closing valve 41, and the bypass pipeline is provided with a bypass regulating valve 42. The regulating quick-closing valve 41 is arranged close to the inlet of the small-sized radial flow turboexpander 7. The function of adjusting the quick-closing valve 41 to integrate the adjusting valve and the quick-closing valve into a whole simplifies the arrangement of the valve on the air inlet pipeline, and is closer to the inlet of the small-sized radial flow turboexpander 7, so that the cutting-off effect is more obvious. The quick closing time of the adjusting quick closing valve 41 is less than 0.5s, and the high-precision hydraulic design is adopted, so that the adjusting precision is high, and the response speed is high. The bypass regulating valve 42 is used for controlling the inlet pressure of the inlet manifold, and the regulating quick-closing valve 41 is used for controlling the rotating speed of the small-sized radial flow turboexpander 7.

Further, a filter 51 and a flow transmitter 52 are arranged on the main pipeline 12, and the filter 51 is used for filtering impurities in the medium.

The detection device is used for detecting the air inlet pressure of the air inlet manifold 11 and the rotating speed of the small-sized radial flow turboexpander 7 in real time. In the present embodiment, the detection means includes a pressure transmitter 21 for detecting the intake pressure of the intake manifold 11 and a rotation speed transmitter 22 for detecting the rotation speed of the compact radial flow turboexpander 7. Optionally, a rotational speed transmitter 22 is mounted on the output shaft of the gearbox 8.

The control device is used for receiving the external air inlet pressure of the air inlet manifold 11 and the set rotating speed of the small-sized radial flow turboexpander, receiving and adjusting valve state signals fed back by the quick-closing valve 41 and the bypass adjusting valve 42 and detection results sent by the detection device, and controlling and adjusting the opening degrees of the quick-closing valve 41 and the bypass adjusting valve 42, so that the small-sized radial flow turboexpander 7 can operate at the set air inlet pressure and the set rotating speed.

In the embodiment, the control device comprises a human-computer interaction part 31 and a controller 32, and the human-computer interaction part 31 is connected with the controller 32. Optionally, the human-computer interaction part 31 is a touch screen, and the controller 32 is a PLC controller.

The starting process of the starting system of the small radial flow turboexpander according to the embodiment of the invention is as follows:

a. starting the small-sized radial flow turboexpander 7, setting the air inlet pressure of the air inlet manifold 11 to be P1 through a control device, wherein P1= P0+ A, P0 is the air inlet pressure required by starting the preset small-sized radial flow turboexpander (from a static state to the time of realizing rotation), A is a constant value, and is more than or equal to 0 and less than or equal to 0.1MPa, and in the embodiment, P1= P0+0.1 MPa;

b. the control device controls the opening degree of the bypass regulating valve 42 according to the set value P1 of the intake pressure and the measured value of the intake pressure, so that the intake pressure of the intake manifold reaches P1; since the initial measurement value of the intake pressure of the intake manifold 11 is less than P1, in step b, the control means generally gradually decreases the opening degree of the bypass regulator valve 42 to increase the intake pressure of the intake manifold, and optionally PID-controls the opening degree of the bypass regulator valve 42 in accordance with the deviation between the intake pressure set value P1 and the measurement value of the intake pressure so that the intake pressure of the intake manifold reaches P1;

c. after the inlet pressure of the inlet manifold reaches P1, setting the rotation speed of the small-sized radial flow turboexpander to be V0 through the control device, wherein V0 is the preset warming-up rotation speed of the small-sized radial flow turboexpander;

d. the control device controls the opening of the quick-closing valve according to the set rotating speed value V0 and the rotating speed measurement value of the small-sized radial flow turboexpander so that the rotating speed of the small-sized radial flow turboexpander reaches V0; since the small-scale radial flow turboexpander 7 is in a static state before, in step d, the control device generally gradually increases the opening degree of the regulating fast-closing integrated valve 41 to increase the rotation speed of the small-scale radial flow turboexpander 7, and optionally, the control device performs PID control on the opening degree of the regulating fast-closing valve 41 according to the deviation between the rotation speed set value V0 and the rotation speed measured value of the small-scale radial flow turboexpander to make the rotation speed of the small-scale radial flow turboexpander 7 reach V0;

e. after the small-sized radial flow turboexpander runs at the rotating speed V0 for a preset time t (at the moment, the quick-closing integral valve 41 is adjusted to be in a large opening degree), the air inlet pressure of the air inlet main pipe is set to be P through the control device_{Forehead (forehead)}，P_{Forehead (forehead)}The rated air inlet pressure of the small radial flow turbine expansion machine 7; alternatively, 3 minutes ≦ t ≦ 5 minutes, t being 5 minutes in this embodiment, so the state of operation at speed V0 is maintained for 5 minutes for valve warming and warm-up purposes;

f. the control device sets a value P according to the intake pressure_{Forehead (forehead)}And the measured value of the intake pressure controls the opening of the bypass regulating valve so that the intake pressure of the intake manifold 11 reaches P_{Forehead (forehead)}(ii) a In this process, the control device generally maintains the rotational speed set value by gradually decreasing the opening degree of the bypass regulator valve 42, but gradually decreases the opening degree of the regulating quick-closing valve 41 as the intake manifold pressure increases. Alternatively, the control means is responsive to the inlet pressure setpoint P_{Forehead (forehead)}Deviation from the measured value of the intake pressure PID controls the opening of the bypass regulator valve 42 so that the intake pressure of the intake manifold 11 reaches P_{Forehead (forehead)}；

g. The intake pressure of the intake manifold 11 reaches P_{Forehead (forehead)}Then, the rotating speed of the small-sized radial flow turboexpander is controlled by a control deviceIs set to V_{Forehead (forehead)}，V_{Forehead (forehead)}The rated rotating speed of the small radial flow turbine expansion machine 7;

h. the control device is based on the set value V of the rotating speed_{Forehead (forehead)}And the rotating speed measurement value of the small-sized radial flow turboexpander controls the opening of the regulating quick-closing valve 41 so as to ensure that the rotating speed of the small-sized radial flow turboexpander reaches V_{Forehead (forehead)}. Alternatively, the control device sets the value V according to the rotating speed_{Forehead (forehead)}The deviation between the measured value of the rotating speed of the small-sized radial flow turboexpander carries out PID control on the opening degree of the regulating quick-closing valve 41 so as to ensure that the rotating speed of the small-sized radial flow turboexpander reaches V_{Forehead (forehead)}。

In this embodiment, the regulating quick-closing valve 41 is kept fully closed and the bypass regulating valve 42 is kept fully open before starting the small-sized radial flow turboexpander 7 so that the medium passes entirely through the bypass line 13 without entering the main line 12.

The intake pressure P0 required for the start-up of the small-scale radial flow turboexpander 7 and the warm-up rotation speed V0 of the small-scale radial flow turboexpander were obtained by a test comprising the steps of:

the regulating quick-closing valve 41 is kept fully closed, the bypass regulating valve 42 is kept fully open, and all media pass through the bypass pipeline 13 and do not enter the main pipeline 12;

fully opening the regulating quick-closing valve 41;

the opening degree of the bypass regulating valve 42 is gradually reduced, so that the intake pressure of the intake manifold 11 is increased until the opening degree of the regulating quick-closing valve 41 is kept unchanged after the small-sized radial flow turboexpander 7 starts to rotate, the intake pressure value at the moment is recorded as the intake pressure P0 required by the start of the small-sized radial flow turboexpander, and the highest rotation speed which the small-sized radial flow turboexpander 7 can reach is recorded as the warming-up rotation speed V0 (namely, the rotation speed value which the small-sized radial flow turboexpander 7 finally reaches under the condition that the intake pressure is equal to P0).

In any step from the step a to the step h, if the rotating speed measured value of the small-sized radial flow turboexpander 7 exceeds the preset upper rotating speed limit, the control device 7 controls and adjusts the quick closing valve 41 to be fully closed, and the air source is cut off, so that the safety of the unit is ensured.

Further, in step h, the rotation of the small-sized radial flow turboexpander 7Quickly reach V_{Forehead (forehead)}In the process, the control device controls the opening of the regulating quick-closing valve 41, so that the rotating speed increasing rate of the small-sized runoff turboexpander 7 is gradually reduced (namely the speed increasing process is fast first and slow later), the small-sized runoff turboexpander 7 can be further ensured to rapidly and safely pass through a critical rotating speed area, and after the rated rotating speed is reached, the rotating speed overshoot is small and the fluctuation is small.