Boiler energy-saving shutdown system and method

Abstract

The present invention discloses a boiler energy-saving shutdown system and method. The system includes a furnace A and a furnace B. The air inlet of the blower of furnace A has two channels, one of which is connected to the inlet flue of the flue gas purification facility of furnace B through the bypass flue of furnace B, and the other is connected to the atmosphere through the inlet air duct of the blower of furnace A; the air inlet of the blower of furnace B has two channels, one of which is connected to the inlet flue of the flue gas purification facility of furnace A through the bypass flue of furnace A, and the other is connected to the atmosphere through the inlet air duct of the blower of furnace B; when one of the boilers is shut down, the exhausted flue gas passes through the other boiler and is dust-removed by another normally operating boiler before being discharged to the outside, thereby solving the problem of substandard flue gas emissions after the boiler is shut down. After the boiler is shut down, the induced draft fan does not operate in the stall zone of the induced draft fan, so surge does not occur, safety is not endangered, and the service life is extended; the hot air entering the shut-down boiler is introduced into another normally operating boiler to participate in combustion, thereby realizing waste heat utilization.

Description

Technical Field

[0001] The present invention relates to the field of boilers, and in particular to a boiler energy-saving shutdown system and method. Background Art

[0002] As China's economy develops, energy demand continues to surge. In 2019, China's total industrial value added increased by 5.7% year-on-year, with industrial value added above designated size increasing by 5.7%. The production and supply of energy, including electricity and heat, grew by 7%. Profits of industrial enterprises above designated size decreased by 3.3% year-on-year, but profits of energy producers, including electricity and heat, increased by 15.4%.

[0003] With the growing demand for electricity and heat, in order to ensure a safe and stable energy supply, the common practice of most heating stations is to build multiple boilers in one heating station, with some operating normally and the rest serving as standby boilers. After a period of operation, the standby boilers are put into operation, while the original operating boilers need to be shut down for normal inspection and maintenance. After maintenance is completed, they enter normal standby mode, awaiting the next cycle of operation. For biomass fuel boilers, due to the low melting point of biomass ash at around 650°C, ash accumulation is prone to occur on the heating surface tube walls of the furnace. In other words, the boiler ash adheres to the surface of the heating surface tube walls, which not only hinders the normal heat transfer of the boiler's heating surface and reduces the boiler's output, but if severe ash accumulation occurs on the heating surface, it hinders the smooth passage of flue gas, increases the space and resistance of the heating surface, and increases the power consumption of the induced draft fan, wasting electricity.

[0004] In summary, the boiler needs to be shut down regularly or irregularly. However, after the boiler is shut down, the induced draft fan is still in operation, causing the following problems:

[0005] (1) The operation of the induced draft fan leads to increased power consumption.

[0006] (2) After the furnace is shut down, the air volume of the induced draft fan deviates significantly from the designed air volume, causing the induced draft fan to stall and surge, seriously affecting the life of the fan.

[0007] (3) After the furnace is shut down, the dust collector stops operating and the dust discharged into the atmosphere through the induced draft fan and chimney seriously exceeds the standard.

[0008] (4) The furnace is cooled by an induced draft fan. The cooling air needs to pass through a dust collector, and the resistance of the cooling air is large.

[0009] (5) After the boiler is cooled, the temperature of the cooling air is high, and direct discharge causes waste of heat energy and thermal pollution to the environment.

[0010] In summary, after the boiler is shut down, the induced draft fan is used to cool the boiler, which has serious problems such as 1. high power consumption, 2. endangering the safety and life of the induced draft fan, 3. substandard flue gas emissions, and 4. waste of heat energy and environmental thermal pollution. Summary of the Invention

[0011] The present invention aims to provide a safe, environmentally friendly and energy-saving boiler energy-saving shutdown system and method, which can reduce boiler energy consumption, extend system life and avoid energy waste.

[0012] To achieve the above object, the present invention adopts the following scheme:

[0013] A boiler energy-saving shutdown system includes a boiler A and a boiler B; the air inlet end of the boiler A and the air inlet end of the boiler B are respectively connected to the blowers provided therein through air inlet pipes, the exhaust end of the tail flue of the boiler A and the exhaust end of the tail flue of the boiler B are respectively connected to the flue gas purification facilities of the boiler A and the flue gas purification facilities through the flue gas purification facility inlet flues, and each flue gas purification facility is respectively connected to an induced draft fan provided therein;

[0014] The air inlet of the A furnace blower has two channels, one of which is connected to the inlet flue of the B furnace flue gas purification facility through the B furnace bypass flue, and the other is connected to the atmosphere through the A furnace blower inlet duct;

[0015] The air inlet of the B furnace blower has two channels, one of which is connected to the inlet flue of the A furnace flue gas purification facility through the A furnace bypass flue, and the other is connected to the atmosphere through the B furnace blower inlet duct.

[0016] Furthermore, the tail flue outlet of furnace A is connected to two flue gas pipes, a main flue valve of furnace A is provided on the inlet flue of the flue gas purification facility of furnace A connected to the flue gas purification facility of furnace A, and a bypass flue valve of furnace A is provided on the bypass flue of furnace A connected to the blower of furnace B.

[0017] Furthermore, the tail flue outlet of furnace B is connected to two flue gas pipes, a main flue valve of furnace B is provided on the inlet flue of the flue gas purification facility of furnace B connected to the flue gas purification facility of furnace B, and a bypass flue valve of furnace B is provided on the bypass flue of furnace B connected to the blower of furnace A.

[0018] Furthermore, the A furnace blower inlet valve is provided on the A furnace blower inlet duct, and the B furnace blower inlet valve is provided on the B furnace blower inlet duct.

[0019] A boiler energy-saving shutdown method, when boiler A is in operation and boiler B is in shutdown, the blower inlet air duct of boiler A is opened, the bypass flue valve of boiler B is closed, the main flue valve of boiler A is opened, the bypass flue valve of boiler A is closed, and all flue gas generated by boiler combustion passes through the flue gas purification facility and induced draft fan of boiler A;

[0020] When furnace A is in the shutdown cooling process and furnace B is in operation, the main flue valve of furnace A is closed, the bypass flue valve of furnace A is opened, the blower inlet duct of furnace B is opened, the bypass flue valve of furnace B is closed, the blower inlet duct of furnace A is opened, and the blower of furnace B has two air inlets. The first air inlet comes from the blower inlet duct of furnace A, flows through furnace A and the tail flue of furnace A to cool furnace A; the second air inlet comes from the blower inlet duct of furnace B.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The air inlets and tail flues of the two boilers are connected to each other through a bypass flue. When one of the boilers is shut down, its main flue is closed, and the flue gas is not discharged directly, but passes through another boiler and is dust-removed by another normally operating boiler before being discharged. The flue gas is discharged when it meets the standards, thus solving the problem of substandard flue gas emissions after the boiler is shut down.

[0023] After a boiler is shut down, its induced draft fan stops working. The induced draft fan does not consume electricity when it is shut down, which saves electricity. The air entering the shut down boiler is drawn in by the blower of another normally operating boiler. The air entering the shut down boiler cools it. The induced draft fan of the shut down boiler does not operate in the stall zone of the induced draft fan, so surge does not occur, safety is not endangered, and the service life is extended.

[0024] The air entering the shut-down boiler becomes hot air and is not discharged directly but introduced into another normally operating boiler to participate in combustion, thus realizing energy utilization, avoiding energy waste and environmental thermal pollution problems, and realizing waste heat utilization.

[0025] The method of the present invention has the following advantages:

[0026] 1. When furnace A is shut down, the induced draft fan of furnace A does not consume electricity, saving energy. Moreover, it does not operate in the stall zone of the induced draft fan, so surge does not occur, which does not endanger the safety of the induced draft fan of furnace A and extends its service life.

[0027] 2. The flue gas emitted by furnace A is not directly discharged through the induced draft fan of furnace A, but enters furnace B. It is finally discharged after dust removal by furnace B's flue gas purification facility. The flue gas meets the discharge standards, solving the problem of flue gas emissions from furnace A not meeting the standards after the flue gas purification facility of furnace A is shut down.

[0028] 3. The cooling air of furnace A does not pass through the flue gas purification facilities of furnace A, which has high resistance and high power consumption, but enters the blower of furnace B. This cooling method of furnace A further saves energy consumption due to the low resistance of the cooling air.

[0029] 4. During the cooling process of furnace A, air flows through furnace A and the tail flue of furnace A, and the temperature increases significantly. This hot air is discharged into the atmosphere through the induced draft fan of furnace A. The heat energy of this hot air enters the furnace B8 of furnace B and is burned, realizing energy utilization, solving the problems of energy waste and environmental thermal pollution, and realizing the waste heat utilization of furnace A. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the workflow of the present invention;

[0031] In the figure: A1-A furnace induced draft fan, A2-A furnace main flue valve, A3-A furnace bypass flue, A4-A furnace bypass flue valve, A5-A furnace blower air inlet valve, A6-A furnace blower, A7-A furnace air inlet pipe, A8-A furnace, A9-A furnace tail flue, A10-A furnace flue gas purification facility inlet flue, A11-A furnace flue gas purification facility, A12-A furnace blower inlet air Duct, B1-B furnace induced draft fan, B2-B furnace main flue valve, B3-B furnace bypass flue, B4-B furnace bypass flue valve, B5-B furnace blower air inlet valve, B6-B furnace blower, B7-B furnace air inlet pipe, B8-B furnace, B9-B furnace tail flue, B10-B furnace flue gas purification facility inlet flue, B11-B furnace flue gas purification facility, B12-B furnace blower inlet air duct. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below with reference to specific embodiments, but this is not intended to limit the present invention.

[0033] like Figure 1 As shown, the boiler energy-saving shutdown system of the present invention includes furnace A A8 and furnace B B8. Furnace A8 is connected to the inlet flue B10 of the flue gas purification facility of furnace B through the furnace A air inlet pipe A7 and the furnace B bypass flue B3. The air inlet end of furnace A8 is connected to the atmosphere through the furnace A air inlet pipe A7, the furnace A blower A6 and the furnace A blower inlet air duct A12. The exhaust end of furnace A8 is connected to the air inlet end of the tail flue A9 of furnace A. The exhaust end of the tail flue A9 of furnace A is connected to the flue gas purification facility of furnace A through the inlet flue A10 of the flue gas purification facility of furnace A. The flue gas purification facility A11 of furnace A is connected to the induced draft fan A1 of furnace A.

[0034] The outlet flue A9 of the tail flue of furnace A is divided into two routes, one of which is connected to the flue gas purification facility A11 of furnace A through the inlet flue A10 of the flue gas purification facility of furnace A, and the other is connected to furnace B8 through the bypass flue A3 of furnace A, the blower B6 of furnace B, and the air inlet pipe B7 of furnace B.

[0035] The air inlet of furnace A blower A6 has two channels, one of which is connected to the inlet flue B10 of furnace B flue gas purification facility through furnace B bypass flue B3, and the other is connected to the atmosphere through furnace A blower inlet duct A12.

[0036] On the two flue gas pipes connected to the outlet of the tail flue A9 of furnace A, a main flue valve A2 of furnace A is provided on the inlet flue A10 of the flue gas purification facility of furnace A, and a bypass flue valve A4 of furnace A is provided on the bypass flue A3 of furnace A. The bypass flue valve A4 is connected to the inlet of the blower B6 of furnace B. The inlet of the blower B6 of furnace B is also connected to the atmosphere through the blower inlet air duct B12 of furnace B. A blower air inlet valve B5 of furnace B is provided on the blower inlet air duct B12 of furnace B.

[0037] Based on this system, the present invention also provides a boiler energy-saving shutdown method, comprising the following steps:

[0038] 1) When furnace A is in operation and furnace B is in shutdown, furnace A's blower inlet duct A12 is open, furnace B's bypass flue valve B4 is closed, furnace A's main flue valve A2 is open, furnace A's bypass flue valve A4 is closed, and all flue gas generated by boiler combustion passes through furnace A's flue gas purification facility A11 and furnace A's induced draft fan A1;

[0039] 2) During the shutdown and cooling process of furnace A, furnace B is in operation, the main flue valve A2 of furnace A is closed, the bypass flue valve A4 of furnace A is opened, the blower inlet duct B12 of furnace B is opened, the bypass flue valve B4 of furnace B is closed, the blower inlet duct A12 of furnace A is opened, and the blower B6 of furnace B has two air inlets. The first air inlet comes from the blower inlet duct A12 of furnace A, flows through furnace A8 and the tail flue A9 of furnace A to cool furnace A; the second air inlet comes from the blower inlet duct B12 of furnace B.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific implementation methods of the present invention may still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims.

Claims

1. A boiler energy-saving shutdown system, characterized by: It comprises a furnace A (A8) and a furnace B (B8); the air inlet end of the furnace A (A8) and the air inlet end of the furnace B (B8) are respectively connected to the blowers provided therein through air inlet pipes, the exhaust end of the tail flue (A9) of the furnace A and the exhaust end of the tail flue (B9) of the furnace B are respectively connected to the flue gas purification facilities of the furnace A and the furnace B through the flue gas purification facility inlet flue, and each flue gas purification facility is respectively connected to the induced draft fan provided therein; The air inlet of the furnace A blower (A6) has two passages, one of which is connected to the inlet flue gas duct (B10) of the flue gas purification facility of furnace B through the bypass flue duct (B3) of furnace B, and the other is connected to the atmosphere through the inlet air duct (A12) of the furnace A blower; The air inlet of the furnace B blower (B6) has two channels, one of which is connected to the flue gas purification facility inlet flue (A10) of furnace A through the bypass flue (A3) of furnace A, and the other channel is connected to the atmosphere through the inlet air duct (B12) of the furnace B blower; The outlet of the tail flue (A9) of furnace A is connected to two flue gas pipelines. A main flue valve (A2) of furnace A is provided on the flue inlet (A10) of furnace A flue gas purification facility connected to the flue gas purification facility (A11) of furnace A, and a bypass flue valve (A4) of furnace A is provided on the bypass flue (A3) of furnace A connected to the blower (B6) of furnace B. The outlet of the tail flue (B9) of furnace B is connected to two flue gas pipelines. A main flue valve (B2) of furnace B is provided on the flue inlet (B10) of furnace B flue gas purification facility connected to the flue gas purification facility (B11) of furnace B, and a bypass flue valve (B4) of furnace B is provided on the bypass flue (B3) of furnace B connected to the blower (A6) of furnace A.

2. The boiler energy-saving shutdown system according to claim 1, characterized in that: The A furnace blower inlet air duct (A12) is provided with an A furnace blower air inlet valve (A5), and the B furnace blower inlet air duct (B12) is provided with a B furnace blower air inlet valve (B5).

3. A boiler energy-saving shutdown method based on the system according to claim 1 or 2, characterized in that: When furnace A is in operation and furnace B is in shutdown, the blower inlet duct (A12) of furnace A is opened, the bypass flue valve (B4) of furnace B is closed, the main flue valve (A2) of furnace A is opened, the bypass flue valve (A4) of furnace A is closed, and all flue gas generated by boiler combustion passes through the flue gas purification facility (A11) of furnace A and the induced draft fan (A1) of furnace A. When furnace A is in the shutdown cooling process and furnace B is in operation, the main flue valve (A2) of furnace A is closed, the bypass flue valve (A4) of furnace A is opened, the blower inlet duct (B12) of furnace B is opened, the bypass flue valve (B4) of furnace B is closed, the blower inlet duct (A12) of furnace A is opened, and the blower (B6) of furnace B has two air inlets. The first air inlet comes from the blower inlet duct (A12) of furnace A, flows through furnace A (A8) and the tail flue (A9) of furnace A to cool furnace A; the second air inlet comes from the blower inlet duct (B12) of furnace B.

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