CN113513767B - A device and method for switching and stabilizing combustion of coal pulverizers in deep peak-shaving coal-fired units - Google Patents

Abstract

The invention relates to a switching and stable combustion device and a method for a coal mill of a deep peak shaving coal-fired unit, which are technically characterized in that: a communication coal powder pipeline is established between a coal powder pipeline of a coal mill and a corresponding coal powder pipeline of another coal mill, a communication door is arranged on each coal powder pipeline, the coal mill and an outlet door and a communication door of the coal mill are all connected with a computer control system capable of collecting, calculating and outputting, the computer control system is also connected with a coal-fired unit to collect real-time load of the coal-fired unit, and further the opening of a coal mill switch, the outlet door and the communication door are controlled, so that the coal mill of the deep peak-shaving coal-fired unit is switched to have a stable combustion function. The invention has reasonable design, improves the combustion stability of the hearth of the deep peak-shaving boiler, solves the problem of low-load combustion stability of the double-layer coal mill, solves the problem of vibration abrasion caused by the reduction of the coal quantity when a single coal mill operates, and reduces the loss of equipment while improving the peak-shaving capacity of a unit.

Description

A device and method for switching and stabilizing combustion of coal pulverizers in deep peak-shaving coal-fired units

technical field

The invention belongs to the technical field of power generation, and relates to a control device of a coal-fired unit, in particular to a device and method for switching and stabilizing combustion of a coal pulverizer of a deep peak-shaving coal-fired unit.

Background technique

As the proportion of new energy installed capacity continues to increase, the problem of peak-shaving capacity of the power system has become more prominent, and solving the problem of new energy consumption has also been put on the agenda. Therefore, the deep peak-shaving of thermal power generating units has become a hot topic. At present, coal-fired units are constantly undergoing flexible transformation, which makes the peak-shaving capacity of the units constantly adapt to the current situation, but a series of problems caused by the continuous reduction of unit output will be put on the agenda.

With the continuous reduction of power generation load, the first consideration of coal-fired units is the problem of low-load stable combustion. If a single coal mill is used, the stable combustion effect is difficult to guarantee. If it is used for combustion, it will cause a great waste of energy. At the same time Increase the risk of unqualified emission indicators; if double coal pulverizers are used, the continuously reduced coal volume is another test for the operation of the current direct-fired coal pulverizer, the coal volume is reduced, and the small gap friction and wear of the grinding rollers , will bring greater hidden danger to the safety of the generating set.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a device and method for switching and stabilizing combustion of coal pulverizers of deep peak-shaving coal-fired units with reasonable design, stable reliability and reduced equipment loss.

The present invention solves the existing technical problems by taking the following technical solutions:

A coal pulverizer switching and stable combustion device for deep peak-shaving coal-fired units, including two coal pulverizers, each coal pulverizer includes a pulverized coal inlet, primary air inlet and multiple pulverized coal outlets, and each pulverizer The pulverized coal outlets are respectively connected to the furnace through pulverized coal pipelines, and there is an outlet door on each pulverized coal pipeline, between the pulverized coal pipeline of one pulverizer and the pulverized coal pipeline corresponding to the other pulverizer. Establish a connecting pulverized coal pipeline, each pulverized coal pipeline is provided with a connecting door, the coal mill, the outlet door of the coal mill, and the connecting door are all connected with a computer control system that can collect, calculate and output. The control system is also connected with the coal-fired unit to collect the real-time load of the coal-fired unit, and then controls the opening of the coal mill switch, the exit door and the contact door, and realizes the function of switching and stabilizing the combustion of the coal-fired unit for deep peak regulation.

Further, each pulverizer has four pulverized coal outlets, four pulverized coal pipelines, four outlet doors, and four connecting doors.

Further, the coal pulverizer is a direct blowing coal pulverizer.

A method for switching a stable combustion device for a coal pulverizer of a deep peak-shaving coal-fired unit, comprising the following steps:

Step 1. The computer control system detects the real-time load P1 of the coal-fired unit. When the real-time load P1 of the coal-fired unit drops to the upper limit of the work of a single coal mill, stop the second coal mill and close the second coal mill the exit door of the machine;

Step 2. The first coal mill is running normally, and all the exit doors of the coal mill are opened;

Step 3. When the real-time load P1 of the coal-fired unit gradually decreases, the computer control system slowly opens the contact door;

Step 4. When the real-time load P1 of the coal-fired unit continues to drop to the lower limit of the work of a single coal mill, the computer control system slowly opens the connecting door, and the valve opening of the connecting door is consistent and reaches 100%;

Step 5. When the real-time load P1 of the coal-fired unit gradually increases, the computer control system slowly closes the contact door;

Step 6. When the real-time load P1 of the coal-fired unit reaches the upper limit of the operation of a single coal mill, the computer control system starts the second coal mill and simultaneously opens the exit door of the second coal mill.

Further, the upper limit of the operation of the single coal mill is: P1=0.3P0, and the lower limit of the operation of the single coal mill is: P1=0.15P0; P0 is the rated load of the coal-fired unit.

Further, in step 3, when the real-time load P1 of the coal-fired unit drops to 0.25P0, the computer control system slowly opens each contact door and makes the valve openings of each contact door consistent and reach 25%; when the coal-fired unit When the real-time load P1 drops to 0.23P0, the computer control system slowly opens each connecting door and makes the valve opening of each connecting door consistent and reaches 50%; when the real-time load P1 of the coal-fired unit drops to 0.20P0, the computer control system slowly Open each connecting door and make the valve opening of each connecting door consistent and reach 75%; the P0 is the rated load of the coal-fired unit.

Further, in step 5, when the real-time load P1 of the coal-fired unit rises to 0.20P0, the computer control system slowly closes each contact door and makes the valve opening of each contact door consistent and reaches 75%; when the coal-fired unit When the real-time load P1 rises to 0.23P0, the computer control system slowly closes each connecting door and makes the valve opening of each connecting door consistent and reaches 50%; when the real-time load P1 of the coal-fired unit rises to 0.25P0, the computer control system slowly Close each connecting door and make the valve opening of each connecting door consistent and reach 25%; when the real-time load P1 of the coal-fired unit rises to 0.27P0, the computer control system completely closes the connecting door and makes the valve opening of each connecting door Consistent and reach 0%; said P0 is the rated load of the coal-fired unit.

Advantage and positive effect of the present invention are:

The design of the present invention is reasonable. It establishes a connecting pulverized coal pipeline between the pulverized coal pipelines at the outlets of two coal mills and sets up a connecting door on the pulverized coal pipeline. The computer control system detects the real-time load of the coal-fired unit and communicates with the coal-fired The rated load of the unit is compared, and the proportion of pulverized coal between the coal seams is controlled by controlling the opening of the outlet door and the contact door of the two coal mills, which improves the reliability of the stable combustion of the deep peak-shaving boiler furnace, and solves the problem of It solves the reliability problem of low-load stable combustion of the double-layer coal mill, and also solves the problem of vibration and wear caused by the reduction of coal volume when a single coal mill is running, and reduces the loss of equipment while improving the peak-shaving ability of the unit .

Description of drawings

Fig. 1 is the structure schematic diagram of the coal pulverizer switching stable combustion device of the deep peak-shaving coal-fired unit of the present invention;

Fig. 2 is the structural schematic diagram of the existing double coal mill switching stable combustion device;

In the figure, A1, A2, A3, A4 are the four exit doors of A coal mill, B1, B2, B3, B4 are the four exit doors of B coal mill, A1B1 are the coal mill exit door A1 and the coal pulverizer The connecting coal pulverized pipeline between the coal mill outlet door B1, A2B2 is the connecting coal pulverized pipeline between the coal mill outlet door A2 and the coal mill outlet door B2, and A3B3 is the coal mill outlet door A3 and the coal mill outlet door B3 A4B4 is the connecting pulverized coal pipeline between the outlet door A4 of the coal mill and the outlet door B4 of the coal mill, AB1 is the connecting door on the pulverized coal pipeline A1B1, and AB2 is the pulverized coal pipeline A2B2 AB3 is the connection door on the connection pulverized coal pipeline A3B3, and AB4 is the connection door on the connection pulverized coal pipeline A4B4.

Detailed ways

Embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 2, the existing double coal mill system includes two coal mills (A coal mill and B coal mill), the coal mills are direct blown coal mills, each coal mill includes a Pulverized coal inlet, primary air inlet and pulverized coal outlet, the four pulverized coal outlets of each pulverizer are respectively connected to the furnace through pulverized coal pipes, and four There are four exit doors of each pulverizer to control the stable combustion of the furnace.

The present invention is improved and realized on the double coal mill system shown in Fig. 2 . As shown in Figure 1, the present invention provides a coal mill switching and stable combustion device for deep peak-shaving coal-fired units, including a set of computer control systems that can collect, calculate and output, A coal mill, B coal mill, each A coal mill includes a pulverized coal inlet, primary air inlet and four pulverized coal outlets, and the four pulverized coal outlets of each pulverized coal mill are respectively connected to the furnace through pulverized coal pipelines. There are four outlet doors A1, A2, A3, A4 on the pulverized coal pipeline, and four outlet doors B1, B2, B3, B4 on the four pulverized coal pipelines of the B pulverizer. The innovation points are: Establish a connecting pulverized coal pipeline A1B1 between the pulverized coal pipeline of the coal mill outlet door A1 and the pulverized coal pipeline on the coal pulverizer outlet door B1, and install the connecting door AB1 on the pulverized coal pipeline A1B1 of the coal mill; A connection pulverized coal pipeline A2B2 is established between the pulverized coal pipeline of the exit door A2 and the pulverized coal pipeline on the exit door B2 of the coal mill, and the connection door AB2 is installed on the pulverized coal pipeline A2B2 of the coal mill; A connection pulverized coal pipeline A3B3 is established between the pulverized coal pipeline and the pulverized coal pipeline on the outlet door B3 of the coal mill, and a connection door AB3 is installed on the pulverized coal pipeline A3B3; the pulverized coal pipeline at the pulverized coal mill outlet door A4 and A connection pulverized coal pipeline A4B4 is established between the pulverized coal pipelines on the outlet door B4 of the coal mill, and a connection door AB4 is installed on the pulverized coal pipeline A4B4. The computer control system that can collect, calculate and output is connected with the coal-fired unit to collect the real-time load of the unit on the one hand, and connected with each coal mill and its exit door (A1, A2, A3, A4, B1, B2, B3, B4) and connecting doors (AB1, AB2, AB3, AB4) are connected, and by controlling the opening of the coal mill switch and the opening of the exit door and connecting door, the switching and stable combustion of coal pulverizers for deep peak-shaving coal-fired units can be realized Function.

Based on the above-mentioned coal mill switching and stable combustion device for deep peak-shaving coal-fired units, the present invention also provides a method for switching and stabilizing combustion of coal mills for deep peak-shaving coal-fired units, including the following steps:

Step 1. Set the rated load of the coal-fired unit as P0, and the computer control system detects the real-time load P1 of the coal-fired unit. When the real-time load P1 of the coal-fired unit drops to 0.3P0 (the upper limit of the work of a single coal mill), stop B coal mill works, and closes four exit doors B1, B2, B3, B4 of B coal mill at the same time.

Step 2. Coal mill A runs normally, and the outlet doors A1, A2, A3, and A4 of coal mill A are all open. As the coal-fired unit continuously reduces the real-time load P1, the pulverized coal volume of coal mill A continues to decrease.

Step 3. When the real-time load P1 of the coal-fired unit drops to 0.25P0, the computer control system slowly opens the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 25%.

Step 4. When the real-time load P1 of the coal-fired unit drops to 0.23P0, the computer control system slowly opens the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 50%.

Step 5. When the real-time load P1 of the coal-fired unit drops to 0.20P0, the computer control system slowly opens the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 75%.

Step 6. When the real-time load P1 of the coal-fired unit continues to drop to 0.15P0 (the lower limit of the work of a single coal mill), the computer control system slowly opens the connecting doors AB1, AB2, AB3, and AB4, and the valves of the four connecting doors open The degree is consistent and reaches 100%.

Step 7. When the real-time load P1 of the coal-fired unit rises to 0.20P0, the computer control system slowly closes the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 75%.

Step 8. When the real-time load P1 of the coal-fired unit rises to 0.23P0, the computer control system slowly closes the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 50%.

Step 9. When the real-time load P1 of the coal-fired unit rises to 0.25P0, the computer control system slowly closes the connecting doors AB1, AB2, AB3, and AB4, and the valve openings of the four connecting doors are consistent and reach 25%.

Step 10. When the real-time load P1 of the coal-fired unit rises to 0.27P0, the connecting doors AB1, AB2, AB3, and AB4 are completely closed, and the valve openings of the four connecting doors are consistent and reach 0%.

Step 11. When the real-time load P1 of the coal-fired unit rises to 0.3P0 (the upper limit of the operation of a single coal mill), the computer control system starts the B coal mill, and simultaneously opens the exit doors B1, B2, and B3 of the B coal mill , B4.

It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, so the present invention includes and is not limited to the embodiments described in the specific implementation, and those skilled in the art according to the technology of the present invention Other implementations derived from the scheme also belong to the protection scope of the present invention.

Claims (4)

1. The switching method of the coal mill switching stable combustion device of the deep peak-shaving coal-fired unit comprises two coal mills, each coal mill comprises a coal powder inlet, a primary air inlet and a plurality of coal powder outlets, the coal powder outlets of each coal mill are respectively connected with a hearth through coal powder pipelines, an outlet door is arranged on each coal powder pipeline, a communication coal powder pipeline is established between the coal powder pipeline of one coal mill and the corresponding coal powder pipeline of the other coal mill, a communication door is arranged on each coal powder pipeline, the coal mills and the outlet doors and the communication doors of the coal mills are connected with a computer control system capable of collecting, calculating and outputting, and the computer control system is also connected with the coal-fired unit to collect real-time loads of the coal-fired unit, so as to control the opening of the coal mill switch, the outlet door and the communication door, and realize the coal mill switching stable combustion function of the deep peak-shaving coal-fired unit, and the switching stable combustion device is characterized in that: the switching method comprises the following steps:

step 1, detecting a real-time load P1 of a coal-fired unit by a computer control system, stopping the operation of a second coal mill and closing an outlet door of the second coal mill when the real-time load P1 of the coal-fired unit is reduced to the upper limit of the operation of a single coal mill;

step 2, the first coal mill normally operates, and outlet doors of the coal mill are all opened;

step 3, when the real-time load P1 of the coal-fired unit gradually descends, the computer control system slowly opens the contact door;

step 4, when the real-time load P1 of the coal-fired unit continuously drops to the lower limit of the work of a single coal mill, slowly opening a contact door by a computer control system, wherein the opening of the contact door is consistent and reaches 100%;

step 5, when the real-time load P1 of the coal-fired unit gradually rises, the computer control system slowly closes the contact door;

and 6, starting a second coal mill by the computer control system when the real-time load P1 of the coal-fired unit reaches the upper limit of the work of the single coal mill, and simultaneously starting an outlet door of the second coal mill.

2. The switching method for switching the stable combustion device of the coal mill of the deep peak shaving coal-fired unit according to claim 1 is characterized by comprising the following steps: the upper limit of the work of the single coal mill is as follows: p1= 0.3P0, the lower limit of the operation of the single coal mill is: p1= 0.15P0; p0 is the rated load of the coal-fired unit.

3. The switching method of the coal mill switching stable combustion device of the deep peak shaving coal-fired unit according to claim 1 or 2, wherein the switching method is characterized by comprising the following steps of: in the step 3, when the real-time load P1 of the coal-fired unit is reduced to 0.25P0, the computer control system slowly opens each contact door and enables the valve opening of each contact door to be consistent and reach 25%; when the real-time load P1 of the coal-fired unit is reduced to 0.23P0, the computer control system slowly opens each contact door and enables the valve opening of each contact door to be consistent and reach 50%; when the real-time load P1 of the coal-fired unit is reduced to 0.20P0, the computer control system slowly opens each contact door and enables the valve opening of each contact door to be consistent and reach 75%; and P0 is the rated load of the coal-fired unit.

4. The switching method of the coal mill switching stable combustion device of the deep peak shaving coal-fired unit according to claim 1 or 2, wherein the switching method is characterized by comprising the following steps of: in the step 5, when the real-time load P1 of the coal-fired unit rises to 0.20P0, the computer control system slowly closes each contact door and enables the valve opening of each contact door to be consistent and to reach 75%; when the real-time load P1 of the coal-fired unit rises to 0.23P0, the computer control system slowly closes each contact door and enables the valve opening of each contact door to be consistent and reach 50%; when the real-time load P1 of the coal-fired unit rises to 0.25P0, the computer control system slowly closes each contact door and enables the valve opening of each contact door to be consistent and reach 25%; when the real-time load P1 of the coal-fired unit rises to 0.27P0, the computer control system completely closes each contact door and enables the valve opening of each contact door to be consistent and reach 0%; and P0 is the rated load of the coal-fired unit.