A method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation

Abstract

The present invention provides a method for TRT blast furnace short-term wind stop electric operation and re-winding and then re-powering operation, the method includes a blast furnace and a TRT, the TRT includes a gas turbine, the gas turbine is connected to a generator; the blast furnace is connected to the gas inlet of the gas turbine through a gas inlet pipeline, and the gas outlet of the gas turbine is connected to a gas outlet pipeline; a bypass pipeline and a pressure reducing pipeline are also provided between the gas inlet pipeline and the gas outlet pipeline; the method includes a method for controlling the electric operation of the TRT when the blast furnace is short-term wind stop; a method for controlling the electric operation of the TRT when the blast furnace is re-winded. The method of the present invention enables the TRT to switch from the power generation state to the power generation state when the blast furnace is short-term wind stop, and at the same time, when the blast furnace is re-winded, the TRT switches from the electric state to the power generation state, thereby avoiding the frequent start and stop of the TRT in a short period of time caused by the impact of the blast furnace wind stop.

Description

Technical Field

[0001] The invention belongs to the technical field of turbine expanders, relates to TRT, and specifically relates to a method for short-term wind-down electric operation of a TRT blast furnace and a method for re-winding and then forwarding electric operation. Background Art

[0002] TRT, or blast furnace gas residual pressure turbine power generation device. In the prior art, when the blast furnace is shut down for a short period of time, the TRT lacks a driving energy source and the device needs to be shut down. After the blast furnace is restored, the device will be restarted. As an energy recovery unit, the TRT can recover 30-50% of the energy required by the blast furnace blower. After the blast furnace is shut down and restored for a short period of time, the TRT needs to be started and stopped quickly accordingly. During the start-up and shutdown process of the device, the on-site operation control is complicated, the operating equipment is numerous, and the workload of the operator is heavy. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for a TRT blast furnace to be operated electrically during a short-term wind-down period and to be operated electrically after the wind is restored, so as to solve the technical problem in the prior art that the TRT needs to be frequently started and stopped when the blast furnace is shut down for a short period of time.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0005] A method for short-term wind-off electric operation of a TRT blast furnace and wind-reopening and then forwarding electric operation, the method comprising a blast furnace and a TRT, the TRT comprising a gas turbine, the gas turbine being connected to a generator; the blast furnace being connected to a gas inlet of the gas turbine via a gas inlet pipeline, the gas outlet of the gas turbine being connected to a gas outlet pipeline; a bypass pipeline and a pressure reducing pipeline are further provided between the gas inlet pipeline and the gas outlet pipeline;

[0006] The method comprises the following steps:

[0007] When the blast furnace is shut down for a short period of time, the electric operation control method of TRT is as follows:

[0008] Step S101, the blast furnace sends a wind-off instruction and sets the generator reverse power protection constant;

[0009] Step S102, the valves on the gas inlet pipe and the gas outlet pipe of the gas turbine are kept in the original open state;

[0010] Step S103, the blast furnace stops supplying air, the pressure of the gas inlet pipeline drops sharply, the power generation of the TRT decreases sharply, and the stationary blades of the gas turbine are manually closed step by step;

[0011] Step S104: when the pressure of the gas inlet pipeline drops to the set pressure value, the stationary blades of the gas turbine are closed to the set opening value, and the bypass pipeline is opened; the valves on the gas inlet pipeline and the gas outlet pipeline of the gas turbine are kept in the original valve position open state;

[0012] Step S105, after the output power of the gas turbine drops to zero, the generator is not decoupled, the TRT still maintains the synchronous speed, the generator obtains power from the grid to absorb active power to meet the power required for the TRT to run electrically, and at the same time sends reactive power to the grid, the generator changes to run as an electric motor;

[0013] Step S106, after the generator is transformed into a motor and operates, the indication direction of the active watt-hour meter of the generator is reversed, and the indication of the reactive watt-hour meter increases;

[0014] Step S107, the outlet gas temperature of the gas pipeline does not exceed the temperature setting value. When it approaches the temperature setting value, low-pressure water spraying and large-scale continuous spraying are planned to achieve cooling effect;

[0015] When the blast furnace is re-aired, the control method of TRT forwarding operation is as follows:

[0016] Step S201, the blast furnace is ready for re-airing, and the bypass pipeline and the pressure reducing pipeline are set to the top pressure automatic control mode;

[0017] Step S202: the pressure of the gas inlet pipeline increases, the gas enters the gas turbine to expand and do work, the shaft end of the gas turbine outputs positive torque, the generator automatically switches to power generation state, and outputs active power to the grid;

[0018] Step S203, gradually opening the stationary blade opening of the gas turbine, and the TRT enters the power increase control mode;

[0019] Step S204, when the pressure of the gas inlet pipeline reaches near the set pressure value, the bypass pipeline and the pressure reducing pipeline are closed, and the TRT enters the automatic top pressure adjustment operation mode; the TRT changes from the electric operation state to the power generation operation state.

[0020] The present invention also has the following technical features:

[0021] The generator is a synchronous generator, and the gas turbine is connected to the generator through a coupling.

[0022] The gas inlet pipeline is provided with an inlet butterfly valve, an inlet plug valve, an inlet gas pressure measuring instrument, an inlet gas temperature measuring instrument, a quick-cut valve and a first butterfly valve in sequence along the gas flow direction, and the quick-cut valve is connected in parallel with a second butterfly valve.

[0023] The gas outlet pipeline is provided with an outlet gas pressure measuring instrument, an outlet gas temperature measuring instrument, an outlet gate valve and an outlet butterfly valve in sequence along the gas flow direction.

[0024] The bypass pipeline is provided with two bypass valves connected in parallel.

[0025] One end of the bypass pipe is connected to the gas inlet pipe between the inlet gas temperature measuring instrument and the quick-cut valve; one end of the bypass pipe is connected to the gas outlet pipe between the outlet gas temperature measuring instrument and the outlet gate valve.

[0026] The pressure reducing pipeline is provided with a pressure reducing valve group.

[0027] One end of the pressure reducing pipeline is connected to the gas inlet pipeline upstream of the inlet butterfly valve, and the other end of the pressure reducing pipeline is connected to the gas outlet pipeline downstream of the outlet butterfly valve.

[0028] In step S101, the reverse power protection setting value is 13%; in step S104, the pressure setting value is 50 kPa; the opening setting value is 8% to 10%; in step S107, the temperature setting value is 100 to 120°C.

[0029] In step S204, the pressure value is set to -10 kPa.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] (I) The method of the present invention enables the TRT to switch from power generation to electric operation when the blast furnace is shut down for a short period of time. At the same time, when the blast furnace is restored to wind, the TRT switches from electric operation to power generation, thereby avoiding the frequent start and stop of the TRT in a short period of time caused by the blast furnace shut down.

[0032] (II) The present invention provides a control method for the TRT to transition from a power generation state to an electric state when the blast furnace is shut down for a short period of time, and to return from an electric state to a power generation state after the blast furnace is restored. By means of the control method for the electric operation of the TRT, the blast furnace shut down will not affect the TRT. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the equipment connection relationship for the TRT blast furnace's short-term wind-off electric operation and the wind-reopening and then forwarding electric operation.

[0034] The meanings of the numbers in the figure are: 1-blast furnace, 2-gas turbine, 3-coupling, 4-generator, 5-inlet gas pipeline, 6-outlet gas pipeline, 7-inlet butterfly valve, 8-inlet gate valve, 9-inlet gas pressure measuring instrument, 10-inlet gas temperature measuring instrument, 11-quick-cut valve, 12-first butterfly valve, 13-second butterfly valve, 14-outlet gas pressure measuring instrument, 15-outlet gas temperature measuring instrument, 16-outlet gate valve, 17-outlet butterfly valve, 18-bypass pipeline, 19-bypass valve, 20-pressure reducing pipeline, 21-pressure reducing valve group.

[0035] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0036] It should be noted that, unless otherwise specified, all components or devices in the present invention are components or devices known in the prior art.

[0037] Wind break: When the blast furnace needs to stop production due to maintenance, accident handling or other reasons, the air supply for smelting is stopped. Wind break time of less than 2 hours is short-term wind break, and more than 2 hours is long-term wind break.

[0038] Re-blowing: refers to the condition in which the blast furnace resumes supplying air for smelting after the wind-down period ends.

[0039] Electric operation: When the blast furnace is in a wind-off state, in order to maintain the operating speed, the TRT needs to switch the generator from the power generation state to the electric operation state. Since the electric operation state needs to obtain power from the power grid, the electric operation is also called reverse power operation.

[0040] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0041] Example:

[0042] This embodiment provides a method for a TRT blast furnace to be operated electrically for a short-term wind-off period and to be operated electrically after wind-reopening. Figure 1 As shown, the method includes a blast furnace 1 and a TRT, the TRT includes a gas turbine 2, and the gas turbine 2 is connected to a generator 4; the blast furnace 1 is connected to the gas inlet of the gas turbine 2 through a gas inlet pipeline 5, and the gas outlet of the gas turbine 2 is connected to a gas outlet pipeline 6; a bypass pipeline 18 and a pressure reducing pipeline 20 are also arranged between the gas inlet pipeline 5 and the gas outlet pipeline 6.

[0043] As a preferred solution of this embodiment, the generator 4 is a synchronous generator, and the gas turbine 2 is connected to the generator 4 through a coupling 3; the coupling 3 can also be replaced by a gearbox, a clutch or a speed-changing clutch as needed.

[0044] As a preferred solution of this embodiment, an inlet butterfly valve 7, an inlet gate valve 8, an inlet gas pressure measuring instrument 9, an inlet gas temperature measuring instrument 10, a quick-cut valve 11 and a first butterfly valve 12 are sequentially arranged on the gas inlet pipeline 5 along the gas flow direction, and a second butterfly valve 13 is connected in parallel to the quick-cut valve 11.

[0045] As a preferred solution of this embodiment, an outlet gas pressure measuring instrument 14, an outlet gas temperature measuring instrument 15, an outlet gate valve 16 and an outlet butterfly valve 17 are sequentially arranged on the outlet gas pipeline 6 along the gas flow direction.

[0046] As a preferred solution of this embodiment, two bypass valves 19 connected in parallel are provided on the bypass pipeline 18 .

[0047] As a preferred solution of this embodiment, one end of the bypass pipe 18 is connected to the gas inlet pipe between the inlet gas temperature measuring instrument 10 and the quick-cut valve 11; one end of the bypass pipe is connected to the gas outlet pipe between the outlet gas temperature measuring instrument 15 and the outlet gate valve 16.

[0048] As a preferred solution of this embodiment, a pressure reducing valve group 21 is provided on the pressure reducing pipeline 20 .

[0049] As a preferred solution of this embodiment, one end of the pressure reducing pipeline 20 is connected to the gas inlet pipeline 5 upstream of the inlet butterfly valve 7, and the other end of the pressure reducing pipeline 20 is connected to the gas outlet pipeline 6 downstream of the outlet butterfly valve 17.

[0050] In this embodiment, the TRT also includes a known and commonly used central control system, a lubricating oil system, a power oil system and a nitrogen sealing system.

[0051] The method comprises the following steps:

[0052] When the blast furnace is shut down for a short period of time, the electric operation control method of TRT is as follows:

[0053] Step S101, blast furnace 1 sends a shutdown command and sets the reverse power protection value of generator 4 to 13%.

[0054] Step S102: The valves on the gas inlet pipe 5 and the gas outlet pipe 6 of the gas turbine 2 are kept in the open state of the original valve positions.

[0055] In step S103, the blast furnace 1 stops supplying air, the pressure of the gas inlet pipe 5 drops sharply, the power generation of the TRT decreases sharply, and the stationary blades of the gas turbine 2 are manually closed step by step.

[0056] Step S104, when the pressure of the gas inlet pipe 5 drops to 50 kPa (relative pressure to the outside), the stationary blades of the gas turbine 2 are closed to an opening of 8% to 10%, and the bypass pipe 18 is opened; the valves on the gas inlet pipe 5 and the gas outlet pipe 6 of the gas turbine 2 are kept in the original open state.

[0057] Step S105, after the output power of the gas turbine 2 drops to zero, the generator 4 is not decoupled, and the TRT still maintains the synchronous speed. The generator 4 obtains electric energy from the grid and absorbs active power to meet the power required for the electric operation of the TRT, while sending reactive power to the grid, and the generator 4 changes to an electric motor.

[0058] Step S106, after the generator 4 changes to the motor operation, the indication direction of the active watt-hour meter of the generator 4 is reversed, and the indication of the reactive watt-hour meter increases.

[0059] Step S107, the outlet gas temperature of the gas pipeline 6 does not exceed 100-120°C. When it approaches 100-120°C, low-pressure water spraying and large-scale continuous spraying are planned to achieve cooling effect.

[0060] When the blast furnace is re-aired, the control method of TRT forwarding operation is as follows:

[0061] Step S201, the blast furnace 1 is ready for re-airing, and the bypass pipe 18 and the pressure reducing pipe 20 are set to the top pressure automatic control mode.

[0062] Step S202, the pressure of the gas inlet pipe 5 increases, the gas enters the gas turbine 2 to expand and do work, the shaft end of the gas turbine 2 outputs positive torque, the generator 4 automatically switches to the power generation state, and outputs active power to the power grid.

[0063] Step S203, gradually open the stationary blade opening of the gas turbine 2, and the TRT enters the power increase control mode.

[0064] Step S204, when the pressure of the gas inlet pipeline 5 reaches the set pressure value -10kPa (relative pressure relative to the outside), the bypass pipeline 18 and the pressure reducing pipeline 20 are closed, and the TRT enters the automatic top pressure adjustment operation mode; the TRT changes from the electric operation state to the power generation operation state.

[0065] In this embodiment, the prerequisites for TRT electric operation are:

[0066] (A) It is clarified that the outage of Blast Furnace 1 is a short-term outage, and the estimated outage time is less than 2 hours. The relevant conditions of the blast furnace outage must comply with the relevant requirements of GB50584-2010.

[0067] (B) TRT must comply with the relevant requirements of GB / T28246, and its thermal performance test must be carried out in accordance with GB / T26137.

[0068] (C) The generator 4 configured in the TRT system must comply with the relevant requirements of GB / T7064-2008 and adapt to long-term operating conditions where the output frequently fluctuates due to input power fluctuations. The exciter should comply with the relevant requirements of GB / T7409.3-2007 and JB / T7784-2006.

[0069] (D) Generator 4 should be able to operate in motor mode. No abnormal conditions should occur within 2 hours of operation of generator 4 in motor mode.

[0070] (E) When the TRT is in electric operation, the lubricating oil system, power oil system and nitrogen sealing system of the unit should all remain in normal operating condition.

[0071] (F) The frequency of electric operation of the TRT unit should not exceed 2 times per day.

[0072] (G) The gas system will not be inspected or maintained during the shutdown period.

[0073] In this embodiment, the matters needing attention for TRT electric operation are as follows:

[0074] a) During the TRT electric operation, all auxiliary systems such as the lubricating oil system, power oil system and nitrogen sealing system must operate normally, and the unit interlocking alarm system must be put into operation normally.

[0075] b) During the electric operation of TRT, the gas pressure entering the gas pipeline 5 shall not be lower than 3 kPa (relative pressure relative to the outside world). If it is lower than this value, the TRT should be stopped manually.

[0076] c) Pay close attention to the temperature of the gas outlet pipeline. When it exceeds 130℃, the TRT should be stopped manually.

[0077] d) When the blast furnace 1 is temporarily shut down, the generator 4 is operated electrically; when the electric operation exceeds 2 hours and is economically unreasonable, the generator 4 should be manually disconnected from the grid and the unit shut down.

[0078] e) During electric operation, if the input power of generator 4 exceeds 15% of the normal power due to some reason, the reverse power protection will issue an alarm signal.

[0079] f) During the electric operation of the unit, the bearing temperature of the gas turbine 2 and the generator 4, the stator temperature of the generator 4 and other parameters are closely monitored. When the temperature exceeds the specified range, an alarm signal is issued.

[0080] g) Electric operation is applicable to dry dust removal blast furnace gas energy recovery turbine power generation unit TRT, wet dust removal blast furnace gas energy recovery turbine power generation unit TRT, dry and wet dual-purpose TRT, and shared TRT; it is not applicable to blast furnace blast and energy recovery unit (ie BPRT), sintering waste heat and blast furnace top pressure energy recovery combined power generation unit (ie STRT).

Claims

1. A method for short-term wind-off electric operation and wind-reopening and then forwarding electric operation of a TRT blast furnace, the method comprising a blast furnace (1) and a TRT, the TRT comprising a gas turbine (2), the gas turbine (2) being connected to a generator (4); the blast furnace (1) being connected to a gas inlet of the gas turbine (2) via a gas inlet pipeline (5), the gas outlet of the gas turbine (2) being connected to a gas outlet pipeline (6); a bypass pipeline (18) and a pressure reducing pipeline (20) are further provided between the gas inlet pipeline (5) and the gas outlet pipeline (6); It is characterized in that The method comprises the following steps: When the blast furnace is shut down for a short period of time, the electric operation control method of TRT is as follows: Step S101, the blast furnace (1) sends a wind-off instruction and sets a reverse power protection constant value of the generator (4); Step S102, the valves on the gas inlet pipe (5) and the gas outlet pipe (6) of the gas turbine (2) are kept in the original open state; Step S103, the blast furnace (1) stops supplying air, the pressure of the gas inlet pipe (5) drops sharply, the power generation of the TRT decreases sharply, and the stationary blades of the gas turbine (2) are manually closed step by step; Step S104, when the pressure of the gas inlet pipeline (5) drops to the set pressure value, the stationary blades of the gas turbine (2) are closed to the set opening value, and the bypass pipeline (18) is opened; the valves on the gas inlet pipeline (5) and the gas outlet pipeline (6) of the gas turbine (2) are kept in the original valve position open state; Step S105, after the output power of the gas turbine (2) drops to zero, the generator (4) is not disconnected, the TRT still maintains the synchronous speed, the generator (4) obtains electric energy from the power grid to absorb active power to meet the power required for the electric operation of the TRT, and at the same time sends reactive power to the power grid, and the generator (4) changes to electric motor operation; Step S106, after the generator (4) is transformed into a motor and operated, the indication direction of the active watt-hour meter of the generator (4) is reversed, and the indication direction of the reactive watt-hour meter increases; Step S107, the outlet gas temperature of the gas pipeline (6) does not exceed the temperature setting value. When it approaches the temperature setting value, low-pressure water spraying and large-volume continuous spraying are planned to achieve cooling effect; When the blast furnace is re-aired, the control method of TRT forwarding operation is as follows: Step S201, the blast furnace (1) is ready for re-airing, and the bypass pipe (18) and the pressure reducing pipe (20) are set to the top pressure automatic control mode; Step S202: the pressure of the gas inlet pipe (5) increases, the gas enters the gas turbine (2) to expand and perform work, the shaft end of the gas turbine (2) outputs positive torque, the generator (4) automatically switches to a power generation state, and outputs active power to the power grid; Step S203, gradually opening the stationary blade opening of the gas turbine (2), and the TRT enters a power increase control mode; Step S204, when the pressure of the gas inlet pipeline (5) reaches near the set pressure value, the bypass pipeline (18) and the pressure reducing pipeline (20) are closed, and the TRT enters the automatic top pressure adjustment operation mode; the TRT changes from the electric operation state to the power generation operation state.

2. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: The generator (4) is a synchronous generator, and the gas turbine (2) is connected to the generator (4) via a coupling (3).

3. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: The gas inlet pipeline (5) is provided with an inlet butterfly valve (7), an inlet gate valve (8), an inlet gas pressure measuring instrument (9), an inlet gas temperature measuring instrument (10), a quick-cut valve (11) and a first butterfly valve (12) in sequence along the gas flow direction, and a second butterfly valve (13) is connected in parallel to the quick-cut valve (11).

4. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 3, characterized in that: An outlet gas pressure measuring instrument (14), an outlet gas temperature measuring instrument (15), an outlet gate valve (16) and an outlet butterfly valve (17) are sequentially arranged on the outlet gas pipeline (6) along the gas flow direction.

5. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: The bypass pipe (18) is provided with two bypass valves (19) connected in parallel.

6. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 4, characterized in that: One end of the bypass pipe (18) is connected to the gas inlet pipe between the inlet gas temperature measuring instrument (10) and the quick-cut valve (11); one end of the bypass pipe is connected to the gas outlet pipe between the outlet gas temperature measuring instrument (15) and the outlet gate valve (16).

7. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: The pressure reducing pipeline (20) is provided with a pressure reducing valve group (21).

8. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 4, characterized in that: One end of the pressure reducing pipeline (20) is connected to the gas inlet pipeline (5) upstream of the inlet butterfly valve (7), and the other end of the pressure reducing pipeline (20) is connected to the gas outlet pipeline (6) downstream of the outlet butterfly valve (17).

9. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: In step S101, the reverse power protection setting value is 13%; in step S104, the pressure setting value is 50 kPa; the opening setting value is 8% to 10%; in step S107, the temperature setting value is 100 to 120°C.

10. The method for TRT blast furnace short-term wind-off electric operation and wind-reopening and subsequent electric operation as claimed in claim 1, characterized in that: In step S204, the pressure value is set to -10 kPa.

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