Method for adjusting boiler load and flue gas temperature

Abstract

The invention discloses a method for adjusting boiler load and flue gas temperature, which comprises a system for adjusting boiler load and flue gas temperature, the system comprises coal economizers, a water supply header pipe, a branch pipe I, a branch pipe II, a branch pipe III, a branch pipe IV, a flue and a boiler barrel, the coal economizers comprise a high-temperature coal economizer and a low-temperature coal economizer which are sequentially arranged in the flue, the branch pipe I is arranged at one end of the economizer, the branch pipe II and the branch pipe III are respectively arranged at the other end of the economizer, the branch pipe IV is connected with an outlet header of the low-temperature economizer and the branch pipe III, the water supply header pipe is respectively connected with the boiler barrel through the branch pipe I, the branch pipe II, the branch pipe III or the branch pipe IV, and the branch pipes are respectively provided with a valve group; the high-temperature economizer and the low-temperature economizer can be connected in series, in parallel or independently operated or isolated, combination of multiple working conditions such as downstream or countercurrent or downstream and countercurrent can be achieved, the boiler load, the smoke exhaust temperature and the inlet smoke temperature of all environment-friendly process equipment can be greatly adjusted, the boiler can be rapidly isolated in an accident, and long-period operation of the boiler is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of boiler load and flue gas temperature regulation, and in particular to a method for regulating boiler load and flue gas temperature. Background Art

[0002] With the gradual improvement of environmental protection requirements and the development of boiler technology, the country has stricter requirements for pollutant emissions, and the temperature level of flue gas directly affects the efficient and economic operation and safety of environmental protection equipment, especially SCR denitrification equipment (including medium-temperature denitrification equipment and low-temperature denitrification equipment), off-furnace dry desulfurization and semi-dry desulfurization equipment, dust removal equipment, etc., all have high requirements for the inlet flue gas temperature level at each (equipment) layout location, and put forward strict requirements for the design and transformation of boilers. At the same time, in view of the characteristics of the enterprise's production process, there are the same use requirements for boiler load and exhaust gas temperature under various loads, which puts forward stringent requirements on boiler load and flue gas temperature in various parts and exhaust gas temperature, especially the requirements for waste heat boiler load and operating temperature points of various equipment. There is an urgent need for a wide range of large-scale regulation methods that can better meet the production process requirements of enterprises, boiler load and exhaust gas temperature and inlet flue gas temperature at each equipment layout location.

[0003] Patent application publication number CN118532671A discloses a flue gas temperature regulating device and method for the tail convection heating surface of a WSC boiler, which is essentially to adjust the heat exchange capacity of the flag tube by adjusting the return water flowing through the flag tube by changing the opening of the flag tube bypass pipeline and its valve group, or even completely isolating the flag tube so that the flag tube does not participate in the operation of the system, and then adjusting or even closing the inlet and outlet valve group of a single economizer heating surface tube bundle (economizer branch pipe) on the economizer side before the denitrification device to adjust the water flow rate flowing through the economizer heating surface tube bundle (economizer branch pipe) before the denitrification device, so as to adjust the economizer heating surface (economizer branch pipe) before the denitrification device. heat exchange; the defects of this patent are: it cannot achieve isolation (non-operating state); there are many regulating valves, with large resistance, and the pipeline, valve group system and control system are very complicated and difficult to adjust, and it is difficult to make the adjustment opening of all valves completely consistent, which is easy to cause uneven flow between the tube bundles of the economizer in front of the denitrification device and cause thermal deviation between the heating surfaces, which is easy to cause accidents such as vaporization and pipe burst; it is not easy to adjust so that many valves maintain the same opening level, and it is not conducive to the safe operation of the economizer in front of the denitrification device; adjusting the flow inside it is also more likely to cause a high accident rate of the flag-shaped tube and the water-cooled wall tube connected thereto, affecting safety and long-term operation, and can only adjust the inlet flue gas temperature of the medium-temperature SCR denitrification equipment, and cannot achieve the inlet flue gas temperature and boiler exhaust gas temperature of the low-temperature SCR denitrification equipment, off-furnace dry desulfurization and semi-dry desulfurization equipment, dust removal equipment, etc. at the layout location of each equipment. Adjustment has great limitations.

[0004] Patent application publication number CN115751286 A discloses "a method for controlling flue gas temperature of a biomass boiler". The control principle of the device is basically consistent with that of "patent application publication number CN109373308 A". Both control the flue gas temperature by controlling the working fluid flow rate of the parallel pipelines. The economizer and the flue gas cooler are both in a single downstream or upstream state, and their isolation and non-operating conditions cannot be achieved. Although the air preheater is arranged outside the flue, the flow change of the parallel air preheater process is used to reduce and adjust the feed water temperature of the economizer and the flue gas cooler, and the inlet and outlet flue gas temperatures of the economizer and the flue gas cooler are adjusted by adjusting the feed water temperature. The adjustment method is single, the temperature adjustment range is small, and the effect is poor. It also has the same defects as the above-mentioned patents.

[0005] Chinese patent application No. 202110583511.0 discloses a composite hot water recirculation system for full-load denitrification of a supercritical power station boiler. By adjusting the water feed flow of the water feed bypass pipeline, the cold water flow entering the economizer to participate in the flue gas heat exchange is reduced, thereby reducing the heat absorption of the economizer. The existing defect is that by putting the composite hot water recirculation system into operation and adjusting the opening of the valve, a pressure-holding effect is achieved. Only by adjusting the valve opening to increase the forced recirculation hot water flow and the cold water bypass flow, the working fluid flow in the economizer is single and constant, the adjustment method is single, and the economizer cannot be isolated, which has great limitations. When an accident occurs on the heating surface of the economizer, the furnace must be shut down immediately, which seriously affects the normal production and operation activities of the enterprise, that is, it also has the same defects as the above-mentioned patent.

[0006] In view of the above problems, a method for adjusting boiler load and flue gas temperature is proposed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for adjusting the boiler load and flue gas temperature, which can realize the series or parallel connection of high-temperature economizers and low-temperature economizers or their independent operation or isolation and non-operation, and select multiple operating conditions such as downstream or countercurrent or upstream and countercurrent during operation to meet the needs of significantly adjusting the boiler load, the flue gas temperature after the high-temperature economizer and the boiler exhaust temperature and the requirements of various environmental protection equipment processes for its inlet flue gas temperature. Economizers of each level can be independently put into operation or not, which is beneficial to the long-term operation of the boiler and the extension of the maintenance cycle. Due to the presence of each valve group, accidents such as leaking economizers can be isolated to maintain the boiler's continued efficient operation, which can effectively solve the problems in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: a method for adjusting boiler load and flue gas temperature, including a system for adjusting boiler load and flue gas temperature, the system including an economizer, a water supply main, branch pipe 1, branch pipe 2, branch pipe 3, branch pipe 4, a flue and a boiler drum, the economizer including a high-temperature economizer and a low-temperature economizer, branch pipe 1, branch pipe 2 and branch pipe 3 are arranged in parallel, branch pipe 1 is arranged at one end of the economizer on the water supply main side, branch pipe 2 and branch pipe 3 are respectively arranged at The other end of the economizer is connected to the low-temperature economizer inlet header. Branch pipe 4 is arranged between the low-temperature economizer outlet header and valve group 4 and connected to branch pipe 3. The water supply main is connected to the boiler drum through branch pipe 1, branch pipe 2, branch pipe 3 or branch pipe 4 respectively. Valve group 9 and valve group 10 are arranged on branch pipe 1, valve group 11 is arranged on branch pipe 2, valve group 13 is arranged on branch pipe 3, and valve group 12 is arranged on branch pipe 4. The high-temperature economizer and the low-temperature economizer are arranged from top to bottom along the flue gas flow direction. It is arranged in the flue, the high-temperature economizer is composed of a high-temperature economizer inlet header, a high-temperature economizer tube bundle and a high-temperature economizer outlet header, the low-temperature economizer is composed of a low-temperature economizer inlet header, a low-temperature economizer tube bundle and a low-temperature economizer outlet header, the low-temperature economizer inlet header is arranged on the water supply main, the left and right ports of the low-temperature economizer inlet header are respectively provided with valve group two and valve group one, the left and right ports of the low-temperature economizer outlet header are respectively provided with valve group four and valve group three, the valve group 11 is connected in series between valve group 2 and valve group 4, valve group 9 is connected in series between valve group 3 and valve group 5, the left and right ports of the high-temperature economizer inlet header are respectively provided with valve group 6 and valve group 5, the left and right ports of the high-temperature economizer outlet header are respectively provided with valve group 8 and valve group 7, and valve group 7 is connected to the boiler drum through valve group 10; the method includes a full countercurrent working method, a full downstream working method, an economizer downstream or countercurrent independent working method, and a water supply method for the economizer or the boiler drum from a feedwater main; The full countercurrent working method includes: full countercurrent working method 1 and full countercurrent working method 2; Full countercurrent working method 1: Close valve group 3, valve group 9, valve group 5, valve group 8, valve group 12, valve group 11, valve group 2, open valve group 1, valve group 4, valve group 6, valve group 7, valve group 10, valve group 13 can be in any state, at this time, the high-temperature economizer and the low-temperature economizer are in series and countercurrent state, all the boiler drum feed water enters the high-temperature economizer after countercurrent heating by the low-temperature economizer, and enters the boiler drum through branch pipe 1 after countercurrent heating by the high-temperature economizer again; Full countercurrent working method 2: Close valve group 1, valve group 3, valve group 10, valve group 6, valve group 7, valve group 4, valve group 13, open valve group 9, valve group 5, valve group 8, valve group 11, valve group 2, valve group 12. At this time, the high-temperature economizer and the low-temperature economizer are in series and countercurrent state. The boiler drum feed water is all heated by the high-temperature economizer in countercurrent and then enters the low-temperature economizer. After being heated by the low-temperature economizer in countercurrent again, it enters the boiler drum through branch pipes 4 and 3. The full-stream working method includes: full-stream working method 1 and full-stream working method 2; Full downstream working method 1: Close valve group 1, valve group 9, valve group 7, valve group 6, valve group 12, valve group 4, valve group 13, open valve group 3, valve group 2, valve group 11, valve group 8, valve group 5, valve group 10, then the high temperature economizer and the low temperature economizer are in series and downstream state, and the boiler drum feed water is all heated by the low temperature economizer downstream from branch pipe 1 and then enters the high temperature economizer, and then enters the boiler drum through branch pipe 1 after being heated by the high temperature economizer downstream again; Full downstream working method 2: Close valve group 1, valve group 3, valve group 5, valve group 10, valve group 8, valve group 12, valve group 11, open valve group 9, valve group 7, valve group 6, valve group 4, valve group 2, valve group 13, then the high-temperature economizer and the low-temperature economizer are in series and downstream state, and the boiler drum feed water is all heated by the high-temperature economizer downstream from branch pipe 1 and then enters the low-temperature economizer, and then enters the boiler drum through branch pipe 3 after being heated downstream from the low-temperature economizer again; Economizer downstream or upstream independent working method: including the operating conditions of low-temperature economizer upstream into the boiler drum, the operating conditions of low-temperature economizer downstream into the boiler drum, the operating conditions of high-temperature economizer upstream into the boiler drum, and the operating conditions of high-temperature economizer downstream into the boiler drum; The low-temperature economizer reverses into the boiler drum in the operating condition, close valve group 3, valve group 9, valve group 2, valve group 4, valve group 13, open valve group 1 and valve group 12, and the low-temperature economizer reverses into the boiler drum through branch pipes 4 and 3 to achieve the operating condition; The low-temperature economizer flows downstream into the boiler drum. Close valve group 1, valve group 9, valve group 4, valve group 12, and valve group 11, and open valve group 3, valve group 2, and valve group 13 to achieve the low-temperature economizer flowing downstream through branch pipe 3 into the boiler drum. The high-temperature economizer reverses into the boiler drum in the operating condition, close valve group seven, valve group ten, valve group six, valve group four, valve group two, open valve group nine, valve group five, valve group eight, valve group eleven, valve group thirteen, then the high-temperature economizer reverses into the boiler drum through branch pipes two and three to achieve the operating condition; The high-temperature economizer flows downstream into the boiler drum. Close valve group 5, valve group 10, valve group 8, valve group 4, valve group 2, and open valve group 9, valve group 7, valve group 6, valve group 11, and valve group 13. Then, the high-temperature economizer flows downstream through branch pipes 2 and 3 into the boiler drum. The water supply method of the water supply main to the economizer or boiler drum: through the cooperation of various valve groups, the water supply main can supply water to the economizer starting from the low-temperature economizer alone; the water supply main can supply water to the economizer starting from the high-temperature economizer alone; the water supply main can supply water to each economizer separately starting from the low-temperature economizer and the high-temperature economizer at the same time; the water supply main can directly supply water to the boiler drum through a branch pipe.

[0009] Furthermore, it also includes a working method for freely isolating the high-temperature economizer and the low-temperature economizer: under any working condition, close valve group 1, valve group 2, valve group 3, and valve group 4 to realize the working condition of complete isolation of the low-temperature economizer; close valve group 5, valve group 6, valve group 7, and valve group 8 to realize the working condition of complete isolation of the high-temperature economizer; open valve group 9 and valve group 10, close valve group 1, valve group 3, valve group 5, valve group 7, valve group 2 (2), valve group 4 (4), valve group 12 (12), valve group 6 (6), and valve group 8 (8), then realize the working condition of isolating the high-temperature economizer and the low-temperature economizer at the same time, that is, the feed water is no longer heated by the economizer but directly enters the boiler drum through branch pipe 1.

[0010] Furthermore, it also includes the combined operating conditions of the parallel system: in the operating conditions of each group of economizers operating in the upstream or downstream direction, through the cooperation of other valve groups, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum, the operating conditions of the low-temperature economizer downstream entering the boiler drum, the operating conditions of the high-temperature economizer countercurrently entering the boiler drum and the operating conditions of the high-temperature economizer downstream entering the boiler drum can be freely combined into: the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer countercurrently entering the boiler drum in parallel, the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer downstream entering the boiler drum in parallel, the operating conditions of the low-temperature economizer downstream and the high-temperature economizer upstream entering the boiler drum in parallel.

[0011] Furthermore, it also includes the combined operating conditions of the series system; in the operating conditions of each group of economizers operating in the upstream or downstream direction, through the cooperation of other valve groups, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum, the operating conditions of the low-temperature economizer downstream entering the boiler drum, the operating conditions of the high-temperature economizer countercurrently entering the boiler drum and the operating conditions of the high-temperature economizer downstream entering the boiler drum can be freely combined into: the operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer countercurrent entering the boiler drum in series, the operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer downstream entering the boiler drum in series, the operating conditions of the low-temperature economizer downstream and the high-temperature economizer countercurrent entering the boiler drum in series, and the operating conditions of the low-temperature economizer downstream and the high-temperature economizer downstream entering the boiler drum in series.

[0012] Furthermore, in the combined operating condition of the parallel system, under any operating condition: through the coordination of the valve group, the water supply main starts to supply water to the economizer from the low-temperature economizer and the high-temperature economizer respectively.

[0013] Furthermore, in the combined operating conditions of the series system, under any operating conditions: through the cooperation of the valve group, the water supply main can start supplying water from the low-temperature economizer, flow from the low-temperature economizer through the high-temperature economizer and then enter the operating condition of the boiler drum; the water supply main can also start supplying water from the high-temperature economizer, flow from the high-temperature economizer through the low-temperature economizer and then enter the operating condition of the boiler drum.

[0014] Furthermore, under any operating condition: through the cooperation of the valve group, the water supply main can directly supply water to the boiler drum through the branch pipe.

[0015] Furthermore, valve group 1, valve group 2, valve group 3, valve group 4, valve group 5, valve group 6, valve group 7, valve group 8, valve group 9, valve group 10, valve group 11, valve group 12 and valve group 13 use electric or pneumatic valves with adjustment functions.

[0016] Furthermore, the working medium flow in the corresponding economizer heating surface can be adjusted by adjusting the opening degree of valve group 1, valve group 2, valve group 3, valve group 4, valve group 5, valve group 6, valve group 7 and valve group 8 at the economizer manifold end respectively.

[0017] Furthermore, the working medium flow in the branch pipe and the economizer heating surface can be adjusted by respectively adjusting the opening degree of valve group nine on branch pipe one, valve group eleven on branch pipe two, valve group thirteen on branch pipe three and valve group twelve on branch pipe four.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the conversion of economizer downstream or countercurrent arrangement and its multi-state combination, the separate control of each economizer group in independent operation and non-operation (isolation) and its multi-state combination, the connection mode of economizer in series or parallel and its combination, the independent regulation of the working fluid flow in the economizer and its multi-state combination, etc., it is easy to adjust the boiler load and the working fluid flow, heat exchange conditions and heat exchange of the heating surfaces of each economizer in the tail flue, so as to realize the free and precise regulation of the boiler load and the flue gas temperature of each part, which can not only realize the regulation of the boiler load, but also greatly better meet the strict requirements and precise regulation of the inlet flue gas temperature required for the efficient operation of each environmental protection process equipment under the same load or different loads of the boiler, and at the same time meet the production needs of the different production process characteristics of the enterprise for the boiler load and the exhaust gas temperature under various loads, with a wide adjustment range, a large range of flue gas temperature adjustment, a simple and flexible adjustment method, a large boiler load adjustment margin, and a wider range of application.

[0019] 2. Economizers at all levels can be operated or not operated (isolated) independently, which is also more conducive to the long-term operation of the boiler and the extension of the maintenance cycle; through simple operations between valve groups, the disadvantages of the boiler having to be immediately shut down for maintenance due to boiler heating surface accidents and affecting the normal production and operation activities of the enterprise are completely solved, effectively preventing the accident from expanding. At the same time, it also saves unnecessary operations and costs such as timely maintenance or replacement of other heating surfaces of the boiler and various environmental protection equipment due to economizer heating surface accidents, thus solving the industry's difficult problems.

[0020] 3. In the series-parallel circuit of the economizer, by adjusting the opening size of the valve group at the economizer header end, the working medium flow in the series economizers and the parallel economizers can be conveniently and accurately controlled to achieve the operating conditions of independently controlling the working medium flow in the high-temperature economizer or the low-temperature economizer or simultaneously independently controlling the working medium flow in the high-temperature economizer and the low-temperature economizer and their operating methods. The operating method includes downstream or reverse flow, parallel or series, and various combined operating conditions, and even the independent operation and non-operation (isolation) of each economizer and its multi-state combination, so as to realize the boiler load, high-temperature economizer outlet flue gas temperature and The purpose of regulating the flue gas temperature at the outlet of the low-temperature economizer is to coordinate and adjust the water supply methods such as starting to supply water from the high-temperature economizer or starting to supply water from the low-temperature economizer or starting to supply water from both the high-temperature economizer and the low-temperature economizer through the water supply main, so that the regulation effect of the boiler load and the flue gas temperature is more obvious, the regulation range is wider and the regulation amplitude is larger, and it can better accurately adjust the boiler load and adapt to the flue gas temperature of the inlet flue gas temperature range of various environmental protection process equipment under various boiler loads. The regulation amplitude is large, the regulation range is wide, the control is precise, and it better adapts to the production process and various environmental protection process equipment to the regulation needs of the boiler load and the flue gas temperature.

[0021] 4. The flow regulation, heat exchange condition and heat exchange amount regulation are achieved through the opening of the valve groups on branch pipe 1, branch pipe 2, branch pipe 3 and branch pipe 4 and their combination. Part of the working fluid can flow through the economizer for heat exchange and then enter the boiler drum, while part of the working fluid can directly enter the boiler drum without heat exchange (no heating) or partial heat exchange (partial heating) through the economizer, and the working fluid flow rate flowing through each economizer can be independently and accurately controlled within the range of 0-100% through the valve group, so as to achieve a greater degree of adjustment of the heat exchange condition of the heating surface of each economizer, thereby achieving a more accurate effect of adjusting the boiler load and exhaust temperature and the inlet flue gas temperature required by each environmental protection equipment, with a large adjustment range, good adjustment effect and wider adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the present invention.

[0023] In the figure: 1 valve group 1, 2 valve group 2, 3 valve group 3, 4 valve group 4, 5 valve group 5, 6 valve group 6, 7 valve group 7, 8 valve group 8, 9 valve group 9, 10 valve group 10, 11 valve group 11, 12 valve group 12, 13 valve group 13, 14 branch pipe 1, 15 branch pipe 2, 16 branch pipe 3, 17 branch pipe 4, 18 feed water main, 19 low-temperature economizer inlet header, 20 low-temperature economizer tube bundle, 21 low-temperature economizer outlet header, 22 SCR denitrification device, 23 high-temperature economizer inlet header, 24 high-temperature economizer tube bundle, 25 high-temperature economizer outlet header, 26 flue, 27 boiler drum. DETAILED DESCRIPTION

[0024] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one end", "the other end", "one side", "the other side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] See also Figure 1The present invention provides a technical solution: a method for adjusting boiler load and flue gas temperature, including a system for adjusting boiler load and flue gas temperature, the system including an economizer, a water supply main 18, a branch pipe 14, a branch pipe 2 15, a branch pipe 3 16, a branch pipe 4 17, a flue 26 and a drum 27, the economizer including a high-temperature economizer and a low-temperature economizer, the branch pipe 14, the branch pipe 2 15 and the branch pipe 3 16 are arranged in parallel, the branch pipe 14 is arranged at one end of the economizer on the side of the water supply main 18, the branch pipe 2 15 and the branch pipe 3 16 are respectively arranged at the other end of the economizer, and connected to the low-temperature economizer inlet header 19 The branch pipe 4 17 is arranged between the low-temperature economizer outlet header 21 and the valve group 4 4 and is connected to the branch pipe 3 16. The branch pipe 1 14 and the branch pipe 2 15 are respectively connected to the valve groups at the corresponding ends of the economizer header. The branch pipe 1 14 and the branch pipe 3 16 are respectively connected to the low-temperature economizer inlet header 19 and the boiler drum 27. The feed water main 18 is connected to the boiler drum 27 through the branch pipe 1 14, the branch pipe 2 15, the branch pipe 3 16 or the branch pipe 4 17. The branch pipe 1 14 is provided with a valve group 9 9 and a valve group 10 10, the branch pipe 2 15 is provided with a valve group 11 11, the branch pipe 3 16 is provided with a valve group 13 13, and the branch pipe 1 A valve group twelve 12 is arranged on the four 17, and the high-temperature economizer and the low-temperature economizer are arranged in the flue 26 from top to bottom along the flue gas flow direction. The high-temperature economizer is composed of a high-temperature economizer inlet header 23, a high-temperature economizer tube bundle 24 and a high-temperature economizer outlet header 25. The low-temperature economizer is composed of a low-temperature economizer inlet header 19, a low-temperature economizer tube bundle 20 and a low-temperature economizer outlet header 21. The low-temperature economizer inlet header 19 is arranged on the water supply main 18. The left and right ports of the low-temperature economizer inlet header 19 are respectively provided with valve group two 2 and valve group one 1. The left and right ports of the low-temperature economizer outlet header 21 are respectively provided with valve group two 2 and valve group one 1. The ports are respectively provided with valve group four 4 and valve group three 3, valve group eleven 11 is connected in series between valve group two 2 and valve group four 4, valve group nine 9 is connected in series between valve group three 3 and valve group five 5, the left and right ports of the high-temperature economizer inlet header 23 are respectively provided with valve group six 6 and valve group five 5, the left and right ports of the high-temperature economizer outlet header 25 are respectively provided with valve group eight 8 and valve group seven 7, and valve group seven 7 is connected to the boiler drum 27 through valve group ten 10; the method includes a full countercurrent working method, a full downstream working method, an economizer downstream or countercurrent independent working method, and a water supply method for the economizer or the boiler drum 27 by the water supply main 18; The full countercurrent working method includes: full countercurrent working method 1 and full countercurrent working method 2; Full countercurrent working method 1: close valve group three 3, valve group nine 9, valve group five 5, valve group eight 8, valve group twelve 12, valve group eleven 11, valve group two 2, open valve group one 1, valve group four 4, valve group six 6, valve group seven 7, valve group ten 10, valve group thirteen 13 can be in any state, at this time, the high-temperature economizer and the low-temperature economizer are in series and countercurrent state, and the feed water of the boiler drum 27 is all heated by the low-temperature economizer in reverse flow and enters the high-temperature economizer, and then enters the boiler drum 27 through the branch pipe one 14 after being heated by the high-temperature economizer in reverse flow again; that is, the working medium in the feed water main 18 countercurrently passes through the low-temperature economizer inlet header 19, the low-temperature economizer tube bundle 20 and the low-temperature economizer outlet header 21 in turn, and then enters the high-temperature economizer inlet header 23 through the branch pipe two 15, and then countercurrently passes through the high-temperature economizer tube bundle 24 and the high-temperature economizer outlet header 25 in turn, and then enters the boiler drum 27 through the branch pipe one 14. This method is a normal operating design condition under normal load of the drum 27, which is a full countercurrent condition under which all working fluids flow through the low-temperature economizer and the high-temperature economizer in series. At this time, the heat exchange effect of the entire economizer is the best, but the feed water of the high-temperature economizer is high-temperature water heated by the low-temperature economizer. The heat exchange effect of the high-temperature economizer is relatively poor, and the heat exchange effect of the low-temperature economizer is relatively good. The flue gas temperature after the high-temperature economizer is higher, that is, the flue gas temperature entering the SCR denitration device 22 is higher; Full countercurrent working method 2: Close valve group 1, valve group 3, valve group 10, valve group 6, valve group 7, valve group 4, valve group 13, and open valve group 9, valve group 5, valve group 8, valve group 11, valve group 2, and valve group 12. At this time, the high-temperature economizer and the low-temperature economizer are in a series and countercurrent state, and all the feed water of the boiler drum 27 enters the low-temperature economizer after countercurrent heating by the high-temperature economizer, and enters the boiler drum 27 through branch pipe 4 17 and branch pipe 3 16 after countercurrent heating by the low-temperature economizer again; that is, the working medium in the feed water main 18 countercurrently passes through the high-temperature economizer inlet header 23, the high-temperature economizer tube bundle 24 and the high-temperature economizer outlet header 24 in turn, and then enters the low-temperature economizer inlet header through branch pipe 2 15. 19, and then countercurrently passes through the low-temperature economizer tube bundle 20, the low-temperature economizer outlet header 21 in turn, and then enters the boiler drum 27 through the branch pipe four 17 and the branch pipe three 16; this method is a full countercurrent condition under which all working fluids flow through the high-temperature economizer and the low-temperature economizer in series, and the feed water of the high-temperature economizer is the unheated low-temperature water of the feed water main 18, and the low-temperature water is the boiler feed water. The heat exchange effect of the high-temperature economizer is relatively better, and the heat exchange effect of the low-temperature economizer is relatively worse; but compared with the full countercurrent working method 1 under the same conditions, although the heat exchange effect of the overall economizer is basically the same, the flue gas temperature after the high-temperature economizer is relatively low, that is, the flue gas temperature entering the SCR denitrification device 22 is low, and the flue gas temperature after the low-temperature economizer is basically unchanged; The full-stream working method includes: full-stream working method 1 and full-stream working method 2; Full downstream working method 1: Close valve group 1, valve group 9, valve group 7, valve group 6, valve group 12, valve group 4, valve group 13, and open valve group 3, valve group 2, valve group 11, valve group 8, valve group 5, and valve group 10. Then the high-temperature economizer and the low-temperature economizer are in series and downstream state, and the feed water of the boiler drum 27 is all heated by the low-temperature economizer downstream from the branch pipe 14 and enters the high-temperature economizer, and then enters the boiler drum 27 through the branch pipe 14 after being heated downstream from the high-temperature economizer again; that is, the working medium of the feed water main 18 flows downstream through the branch pipe 14, the low-temperature economizer outlet header 21, the low-temperature economizer tube bundle 20, and the low-temperature economizer inlet header 19 in turn, and then passes through Through the branch pipe 2 15, the high-temperature economizer outlet header 25, the high-temperature economizer tube bundle 24, the high-temperature economizer inlet header 23, and then through the branch pipe 1 14 into the boiler drum 27; this method is a full co-current condition in which all working fluids flow through the low-temperature economizer and the high-temperature economizer in series, and the heat exchange effect of the overall economizer is worse than that of the full countercurrent condition, but the feed water of the high-temperature economizer is high-temperature water heated by the low-temperature economizer, and the heat exchange effect of the high-temperature economizer is relatively slightly worse, and the heat exchange effect of the low-temperature economizer is relatively slightly better. Compared with the full countercurrent condition 1 under the same conditions, the flue gas temperature after the high-temperature economizer is higher, that is, the flue gas temperature entering the SCR denitration device 22 is higher, and the flue gas temperature after the low-temperature economizer is also higher; Full downstream working method 2: Close valve group 1, valve group 3, valve group 5, valve group 10, valve group 8, valve group 12, valve group 11, and open valve group 9, valve group 7, valve group 6, valve group 4, valve group 2, and valve group 13. Then the high-temperature economizer and the low-temperature economizer are in series and downstream state, and the feed water of the boiler drum 27 is all heated by the high-temperature economizer downstream from the branch pipe 1, and then enters the low-temperature economizer, and then enters the boiler drum 27 through the branch pipe 3, and then enters the boiler drum 27 through the branch pipe 3, and then enters the boiler drum 27 through the branch pipe 14, the high-temperature economizer outlet header 25, the high-temperature economizer tube bundle 24, the high-temperature economizer inlet header 23, and then passes through the branch pipe 2, the low-temperature economizer outlet header 21, The low-temperature economizer tube bundle 20 and the low-temperature economizer inlet header 19 then enter the boiler drum 27 through the branch pipe three 16; this method is a full co-current condition in which all working fluids flow through the high-temperature economizer and the low-temperature economizer in series. At this time, the heat exchange effect of the overall economizer is worse than that of the full countercurrent condition. Compared with the full co-current working method one under the same conditions, the heat exchange effect of the overall economizer is basically the same, but the feed water of the high-temperature economizer is the unheated low-temperature water of the feed water main 18, which is the boiler feed water. The heat exchange effect of the high-temperature economizer is relatively better, and the heat exchange effect of the low-temperature economizer is relatively worse. Therefore, the flue gas temperature after the high-temperature economizer is relatively low, that is, the flue gas temperature entering the SCR denitrification device 22 is low, and the flue gas temperature after the low-temperature economizer is basically unchanged; Economizer downstream or upstream independent working method: including the operating conditions of low-temperature economizer upstream into the boiler drum 27, the operating conditions of low-temperature economizer downstream into the boiler drum 27, the operating conditions of high-temperature economizer upstream into the boiler drum 27, and the operating conditions of high-temperature economizer downstream into the boiler drum 27; The low-temperature economizer counterflows into the boiler drum 27. Close valve group three 3, valve group nine 9, valve group two 2, valve group four 4, valve group thirteen 13, open valve group one 1, valve group twelve 12, and the low-temperature economizer counterflows into the boiler drum 27 through branch pipe four 17 and branch pipe three 16. Under this counterflow condition, the heat exchange effect of the low-temperature economizer is relatively good, and the outlet flue gas temperature of the low-temperature economizer is relatively low. The low-temperature economizer flows downstream into the boiler drum 27. Close valve group 1 1, valve group 9, valve group 4, valve group 12, valve group 11, and valve group 11 11, and open valve group 3 3, valve group 2 2, and valve group 13 13, so that the low-temperature economizer flows downstream through branch pipe 3 16 into the boiler drum 27. In this downstream condition, the heat exchange effect of the low-temperature economizer is relatively worse than that of the same countercurrent condition, and the outlet flue gas temperature of the low-temperature economizer is relatively high. The high-temperature economizer counterflows into the boiler drum 27. Close valve group seven 7, valve group ten 10, valve group six 6, valve group four 4, valve group two 2, and open valve group nine 9, valve group five 5, valve group eight 8, valve group eleven 11, and valve group thirteen 13. Then, the high-temperature economizer counterflows into the boiler drum 27 through branch pipe two 15 and branch pipe three 16. In this counterflow condition, the heat exchange effect of the high-temperature economizer is relatively good, and the outlet flue gas temperature of the high-temperature economizer is relatively low. The high-temperature economizer enters the boiler drum 27 in the downstream operation condition. Close valve group 5, valve group 10, valve group 8, valve group 4, valve group 2, and open valve group 9, valve group 7, valve group 6, valve group 11, and valve group 13. Then, the high-temperature economizer enters the boiler drum 27 in the downstream operation condition through branch pipe 2 15 and branch pipe 3 16. In the downstream operation condition, the heat exchange effect of the high-temperature economizer is relatively worse than that of the same countercurrent operation condition, and the outlet flue gas temperature of the high-temperature economizer is relatively high. The water supply method of the water supply main pipe 18 to the economizer: through the cooperation of each valve group, the water supply main pipe 18 can start to supply water to the economizer from the low-temperature economizer alone; this method is suitable for the working method of the economizer in series or the working method of the low-temperature economizer independently entering the boiler drum 27; The water supply method of the water supply main pipe 18 to the economizer: The water supply main pipe 18 can supply water to the economizer starting from the high-temperature economizer alone; this method is suitable for the working method of the economizer in series or the working method of the high-temperature economizer independently feeding the boiler drum 27; The method of supplying water from the water main pipe 18 to the economizer: the method of supplying water from the water main pipe 18 to each economizer respectively from the low-temperature economizer and the high-temperature economizer at the same time; the method is suitable for the working method in which the low-temperature economizer and the high-temperature economizer both independently enter the boiler drum 27; the method is also suitable for the working method in which the low-temperature economizer and the high-temperature economizer both independently enter the boiler drum 27, but the working medium flow rate flowing through the high-temperature economizer or the low-temperature economizer still needs to be further adjusted or further adjusted at the same time; The method of supplying water from the water main pipe 18 to the economizer or the boiler drum 27: The water main pipe 18 can directly supply water to the boiler drum 27 through the branch pipe 14; this method is suitable for directly isolating the economizers at all levels or adjusting the working medium flow in the branch pipe 14 and the economizers at all levels at the same time; Valve group 1 1, valve group 2 2, valve group 3 3, valve group 4 4, valve group 5 5, valve group 6 6, valve group 7 7, valve group 8 8, valve group 9 9, valve group 10, valve group 11 11, valve group 12 12 and valve group 13 13 use electric or pneumatic valves with adjustment functions.

[0026] High-temperature economizer and low-temperature economizer free isolation working method: Under the downstream or upstream working condition, close valve group one 1, valve group two 2, valve group three 3, valve group four 4, to achieve the low-temperature economizer completely isolated working condition and in a non-operating condition; close valve group five 5, valve group six 6, valve group seven 7, valve group eight 8, to achieve the high-temperature economizer completely isolated working condition and in a non-operating condition; open valve group nine 9, valve group ten 10, close valve group one, valve group three, valve group five, valve group seven, valve group two 2, valve group four 4, valve group twelve 12, valve group six 6, valve group eight 8 , the high-temperature economizer and the low-temperature economizer are isolated from each other at the same time and are in a non-operating condition; the high-temperature economizer and the low-temperature economizer are freely isolated from each other to eliminate the non-operating heat exchange surface of the corresponding economizer and improve the heat exchange condition of the economizer heating surface of the operating part to reduce the heat exchange area involved in the economizer and greatly adjust the boiler load and the flue gas temperature requirements of various parts. At the same time, it is also beneficial to isolate the economizers at all levels in time when they fail, and continue to operate the boiler, so as to prevent the accident from expanding, reduce losses, and not affect the normal production of the enterprise.

[0027] In the parallel operating conditions of economizers at all levels running in the upstream or downstream direction, through the cooperation of other valve groups, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum 27, the operating conditions of the low-temperature economizer downstream entering the boiler drum 27, the operating conditions of the high-temperature economizer countercurrently entering the boiler drum 27 and the operating conditions of the high-temperature economizer downstream entering the boiler drum 27 can be freely combined into: the parallel operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer countercurrent, the parallel operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer downstream, the parallel operating conditions of the low-temperature economizer downstream and the high-temperature economizer countercurrent, and the parallel operating conditions of the low-temperature economizer downstream and the high-temperature economizer downstream.

[0028] The combined working conditions of the parallel system can realize the parallel connection of high-temperature economizer and low-temperature economizer or their independent operation or isolation, and select the downstream or countercurrent and their working conditions combination during operation to meet the requirements of large-scale adjustment of boiler load, flue gas temperature after high-temperature economizer and boiler exhaust temperature and the inlet flue gas temperature of various environmental protection equipment processes. For example: by closing valve group ten 10, valve group five 5, valve group eight 8, opening valve group nine 9, valve group seven 7, valve group six 6, the downstream arrangement of high-temperature economizer can be realized; by closing valve group one 1, valve group four 4, valve group twelve 12, opening valve group three 3, valve group two 2, the downstream arrangement of low-temperature economizer can be realized; at the same time, by opening valve group eleven 11 and valve group thirteen 13, the parallel working conditions of low-temperature economizer downstream and high-temperature economizer downstream can be realized to operate independently and enter the boiler drum 27 through branch pipe two 15 and branch pipe three 16; at the same time, the opening of valve group seven 7 can be adjusted The heat exchange and flue gas temperature can be adjusted by adjusting the working fluid flow rate of the high-temperature economizer by adjusting the opening of valve group three 3, adjusting the working fluid flow rate of the low-temperature economizer by adjusting the opening of valve group seven 7 and valve group three 3 at the same time to adjust the working fluid flow rates of the high-temperature economizer and the low-temperature economizer at the same time; the heat exchange and flue gas temperature can be adjusted more accurately and to a larger extent by the above flow modes and their combinations, working fluid flow rate adjustment methods and their combinations, and combinations of flow modes and working fluid flow rate adjustment methods.

[0029] In the series operating conditions of economizers at all levels operating in downstream or upstream, through the cooperation of other valve groups, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum 27, the operating conditions of the low-temperature economizer downstream entering the boiler drum 27, the operating conditions of the high-temperature economizer countercurrently entering the boiler drum 27 and the operating conditions of the high-temperature economizer downstream entering the boiler drum 27 can be freely combined into: the series operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer countercurrent, the series operating conditions of the low-temperature economizer countercurrent and the high-temperature economizer downstream, the series operating conditions of the low-temperature economizer downstream and the high-temperature economizer countercurrent, and the series operating conditions of the low-temperature economizer downstream and the high-temperature economizer downstream.

[0030] The combined operating conditions of the series system can realize the series operation of the high-temperature economizer and the low-temperature economizer, and select the downstream or countercurrent operating conditions and their combination during operation to meet the requirements of the large-scale adjustment of the boiler load, the flue gas temperature after the high-temperature economizer and the boiler exhaust temperature and the inlet flue gas temperature of various environmental protection equipment processes; such as: closing valve group ten 10, valve group five 5, valve group eight 8, opening valve group nine 9, valve group seven 7, valve group six 6, to realize the downstream arrangement of the high-temperature economizer; closing valve group twelve 12, valve group three 3, valve group one 1, valve group eleven 11, opening valve group four 4, valve group two 2, the downstream arrangement of the low-temperature economizer can be realized; at the same time, in conjunction with opening valve group thirteen 13, the series operation of the high-temperature economizer downstream and the low-temperature economizer downstream can be realized and the operating condition of entering the boiler drum 27 through branch pipe three 16.

[0031] In the above economizer series-parallel circuit, by adjusting the valve group at the economizer manifold end, that is, adjusting the opening size of valve group 1, valve group 2, valve group 3, valve group 4, valve group 5, valve group 6, valve group 7, and valve group 8, the working fluid flow rate in the economizers at various levels in series or the working fluid flow rate in the economizers at various levels in parallel can be conveniently and accurately controlled to achieve the operating conditions of independently controlling the high-temperature economizer or the low-temperature economizer or independently controlling the working fluid flow rate in the high-temperature economizer and the low-temperature economizer and the operating method thereof, and the operating method includes downstream or countercurrent, parallel or series, and various combined operating conditions, thereby achieving the boiler load The purpose of regulating the outlet flue gas temperature of the boiler and the high-temperature economizer and the inlet flue gas temperature of each environmental protection process equipment is to adjust the flue gas temperature of the boiler load and the high-temperature economizer and the inlet flue gas temperature of each environmental protection process equipment, and then assisted by the water supply method of the water supply main 18 starting from the high-temperature economizer or starting from the low-temperature economizer or starting from the high-temperature economizer and the low-temperature economizer at the same time and the adjustment of the working medium flow rate, so that the regulation effect of the boiler load and the flue gas temperature is more obvious, the regulation range and amplitude are wider, and it can better accurately adjust the boiler load and adapt to the flue gas temperature of the inlet flue gas temperature range of each environmental protection process equipment under various boiler loads. The regulation amplitude is large, the regulation range is wide, the control is precise, and it better adapts to the production process and the flue gas temperature regulation needs of various equipment.

[0032] Under the above working conditions, in combination with the opening adjustment of the valve groups on branch pipe 1 14, branch pipe 2 15, branch pipe 3 16, and branch pipe 4 17, the flow rate of the working medium that does not pass through the economizer can be adjusted, that is, through the combination and adjustment of the valve group openings on branch pipe 1 14, branch pipe 2 15, branch pipe 3 16, and branch pipe 4 17, part of the working medium can flow through the economizer for heat exchange and then enter the boiler drum 27, while part of the working medium can directly enter the boiler drum 27 without heat exchange through the branch pipes, and the flow rate of the working medium flowing through each economizer can be independently realized by the valve group connected to the economizer header end 0-1 Precise and controllable regulation within the range of 00%, the working fluid flow in each heating surface is freely distributed and heated evenly, and the heating surface operates safely and reliably. This is different from the rough adjustment achieved by relying solely on the density difference between the heated working fluid in the economizer and the unheated working fluid in the branch pipe, that is, the flow resistance of the economizer in the flue and the total resistance of the parallel unheated branch pipe and its valve group. It can adjust the heat exchange conditions and heat exchange capacity of each economizer heating surface in a wider range, thereby achieving a greater degree of adjustment of the boiler load and exhaust temperature and the inlet flue gas temperature required by various environmental protection process equipment, with wider adaptability and more convenient adjustment.

[0033] The patent of the present invention realizes the conversion of the co-current or countercurrent arrangement of the low-temperature economizer and the high-temperature economizer and its combination, the connection mode of series or parallel connection and its combination between the economizers, and the redistribution and combination of the working medium flow inside the economizer and between the economizers through the switch combination of each valve group. That is, through the conversion of the co-current or countercurrent arrangement and its combination, the separate control and combination of the independent operation and isolation (non-operation) of the economizer, the different connection modes of series or parallel connection and its combination of the economizer, the independent regulation of the flow in the economizer and its multi-state combination, etc., it is easy to adjust the boiler load and the heat exchange conditions and heat exchange amount of the heating surfaces of each economizer in the tail flue, thereby realizing the free regulation of the boiler load, and the production process characteristics of each enterprise and each environment under the same or different boiler loads. Ensure that the process equipment can freely and accurately adjust the exhaust gas temperature, the flue gas temperature after the high-temperature economizer, the flue gas temperature after the low-temperature economizer and the inlet flue gas temperature of each environmental protection equipment in a wide range, so as to achieve the purpose of greatly adjusting the boiler load and its exhaust gas temperature and the inlet flue gas temperature of each environmental protection equipment, so as to meet the production process requirements and adjust the inlet flue gas temperature of each environmental protection equipment separately, so as to better meet the production process characteristics of the enterprise and various environmental protection equipment, such as SCR denitrification equipment (including medium-temperature denitrification and low-temperature denitrification), off-furnace dry desulfurization and semi-dry desulfurization equipment and dust removal equipment, etc., for the boiler load and the exhaust gas temperature under various boiler loads and the inlet flue gas temperature of each environmental protection equipment. Strict requirements, to ensure the normal production process of the enterprise and the safe, economical and efficient operation of various environmental protection equipment.

[0034] In the invention, since economizers at each level can be operated independently or not operated at all (isolated), it is more conducive to the long-term operation of the boiler and the extension of the maintenance cycle; due to the existence of each valve group, the economizer where an accident such as leakage occurs can be completely and independently isolated to maintain the efficient operation of the boiler. Independent isolation means not operating, which can better meet the needs of the company's continuous production process, and enable accidents to be handled in time without expanding, causing huge economic losses to the company, and will not cause any adverse effects or damage to other heating surfaces of the boiler and various environmental protection equipment due to accidents. It can also meet the company's production industrial characteristics and the requirements of various environmental protection equipment for boiler load, exhaust temperature and the inlet flue gas temperature of each environmental protection equipment; through simple operations between the valve groups, without increasing additional equipment costs, it can completely solve the problem that the boiler must be shut down for inspection and treatment immediately due to boiler heating surface accidents such as leakage and affect the normal production and operation activities of the company. At the same time, other heating surfaces of the boiler and various environmental protection equipment are adversely affected by heating surface accidents and need to be repaired and replaced in time, etc., which solves the industry problem.

[0035] The patent of the present invention is also applicable to air preheaters, except that the heating surface is changed to an air preheater and the working medium is changed to air, and the regulating principle is the same.

[0036] The basic principles, main features and advantages of the present invention are shown and described above. Without departing from the spirit and scope of the present invention, the present invention may also be subject to various changes and improvements, which all fall within the scope of the present invention to be protected.

Claims

1. A method for adjusting boiler load and flue gas temperature, characterized in that: A system for regulating boiler load and flue gas temperature is provided, the system comprising an economizer, a water supply main (18), a branch pipe 1 (14), a branch pipe 2 (15), a branch pipe 3 (16), a branch pipe 4 (17), a flue (26) and a boiler drum (27). The economizer comprises a high-temperature economizer and a low-temperature economizer. The high-temperature economizer and the low-temperature economizer are arranged in the flue (26) from top to bottom along the flue gas flow direction. The high-temperature economizer comprises a high-temperature economizer inlet header (23), a high-temperature economizer tube bundle (24) and a high-temperature economizer outlet header (25). The low-temperature economizer comprises a low-temperature economizer inlet header (19), a low-temperature economizer tube bundle (24) and a high-temperature economizer outlet header (25). The low-temperature economizer inlet header (19) is arranged on the water supply main pipe (18), the left and right ports of the low-temperature economizer inlet header (19) are respectively provided with valve group 2 (2) and valve group 1 (1), the left and right ports of the low-temperature economizer outlet header (21) are respectively provided with valve group 4 (4) and valve group 3 (3), the branch pipe 1 (14), the branch pipe 2 (15) and the branch pipe 3 (16) are arranged in parallel, the branch pipe 1 (14) is arranged at one end of the economizer on the water supply main pipe (18), the branch pipe 2 (15) and the branch pipe 3 (16) are respectively arranged at the other end of the economizer, and are connected to the low-temperature economizer outlet header (21). The low-temperature economizer inlet header (19) is connected, the branch pipe four (17) is arranged between the low-temperature economizer outlet header (21) and the valve group four (4) and is connected to the branch pipe three (16), the feed water main (18) is connected to the boiler drum (27) through the branch pipe one (14), the branch pipe two (15), the branch pipe three (16) or the branch pipe four (17), the branch pipe one (14) is provided with a valve group nine (9) and a valve group ten (10), the branch pipe two (15) is provided with a valve group eleven (11), the branch pipe three (16) is provided with a valve group thirteen (13), the branch pipe four (17) is provided with a valve group twelve (12), the valve group eleven (11) is provided with a valve group ) is connected in series between valve group two (2) and valve group four (4), valve group nine (9) is connected in series between valve group three (3) and valve group five (5), left and right ports of the high-temperature economizer inlet header (23) are respectively provided with valve group six (6) and valve group five (5), left and right ports of the high-temperature economizer outlet header (25) are respectively provided with valve group eight (8) and valve group seven (7), and valve group seven (7) is connected to the boiler drum (27) through valve group ten (10); the method includes a full countercurrent working method, a full forward working method, an economizer forward or reverse working method and a water supply method for the economizer or the boiler drum (27) from the water supply main pipe (18); The full countercurrent working method includes: full countercurrent working method 1 and full countercurrent working method 2; Full countercurrent working method 1: close valve group 3 (3), valve group 9 (9), valve group 5 (5), valve group 8 (8), valve group 12 (12), valve group 11 (11), and valve group 2 (2); open valve group 1 (1), valve group 4 (4), valve group 6 (6), valve group 7 (7), and valve group 10 (10). At this time, the high-temperature economizer and the low-temperature economizer are in a series and countercurrent state. The feed water of the boiler drum (27) is all heated by the low-temperature economizer in countercurrent and then enters the high-temperature economizer. After being heated by the high-temperature economizer in countercurrent again, it enters the boiler drum (27) through branch pipe 1 (14); Full countercurrent working method 2: close valve group 1 (1), valve group 3 (3), valve group 10 (10), valve group 6 (6), valve group 7 (7), valve group 4 (4), valve group 13 (13), open valve group 9 (9), valve group 5 (5), valve group 8 (8), valve group 11 (11), valve group 2 (2), valve group 12 (12), at this time, the high-temperature economizer and the low-temperature economizer are in a series and countercurrent state, and the feed water of the boiler drum (27) is all heated by the high-temperature economizer in countercurrent and then enters the low-temperature economizer, and then enters the boiler drum (27) through branch pipe 4 (17) and branch pipe 3 (16) after being heated by the low-temperature economizer in countercurrent again; The full-stream working method includes: full-stream working method 1 and full-stream working method 2; Full co-current working method 1: close valve group 1 (1), valve group 9 (9), valve group 7 (7), valve group 6 (6), valve group 12 (12), valve group 4 (4), valve group 13 (13), open valve group 3 (3), valve group 2 (2), valve group 11 (11), valve group 8 (8), valve group 5 (5), valve group 10 (10), then the high temperature economizer and the low temperature economizer are in series and co-current state, the feed water of the boiler drum (27) is all heated by the low temperature economizer in co-current flow through branch pipe 1 (14) and then enters the high temperature economizer, and then enters the boiler drum (27) through branch pipe 1 (14) after being heated by the high temperature economizer in co-current flow again; Full co-current working method 2: close valve group 1 (1), valve group 3 (3), valve group 5 (5), valve group 10 (10), valve group 8 (8), valve group 12 (12), and valve group 11 (11), and open valve group 9 (9), valve group 7 (7), valve group 6 (6), valve group 4 (4), valve group 2 (2), and valve group 13 (13), then the high-temperature economizer and the low-temperature economizer are in a series and co-current state, and the feed water of the boiler drum (27) is all heated by the high-temperature economizer in co-current flow through branch pipe 1 (14) and then enters the low-temperature economizer, and then enters the boiler drum (27) through branch pipe 3 (16) after being heated by the low-temperature economizer in co-current flow again; The economizer co-current or counter-current independent working method includes the operating conditions of the low-temperature economizer counter-currently entering the boiler drum (27), the operating conditions of the low-temperature economizer co-currently entering the boiler drum (27), the operating conditions of the high-temperature economizer counter-currently entering the boiler drum (27), and the operating conditions of the high-temperature economizer co-currently entering the boiler drum (27); In the operating condition where the low-temperature economizer flows in reverse flow into the boiler drum (27), valve group three (3), valve group nine (9), valve group two (2), valve group four (4), and valve group thirteen (13) are closed, and valve group one (1) and valve group twelve (12) are opened, so that the operating condition where the low-temperature economizer flows in reverse flow into the boiler drum (27) through branch pipe four (17) and branch pipe three (16) is realized; The low-temperature economizer is operated in a downstream flow into the boiler drum (27). The valve group 1 (1), valve group 9 (9), valve group 4 (4), valve group 12 (12), and valve group 11 (11) are closed, and the valve group 3 (3), valve group 2 (2), and valve group 13 (13) are opened, thereby realizing the low-temperature economizer operating condition of downstream flow into the boiler drum (27) through the branch pipe 3 (16); In the operating condition where the high-temperature economizer flows in reverse flow into the boiler drum (27), valve group seven (7), valve group ten (10), valve group six (6), valve group four (4), and valve group two (2) are closed, and valve group nine (9), valve group five (5), valve group eight (8), valve group eleven (11), and valve group thirteen (13) are opened, so that the operating condition where the high-temperature economizer flows in reverse flow into the boiler drum (27) through branch pipe two (15) and branch pipe three (16) is realized; The operating condition in which the high-temperature economizer flows downstream into the boiler drum (27) is achieved by closing valve group five (5), valve group ten (10), valve group eight (8), valve group four (4), and valve group two (2), and opening valve group nine (9), valve group seven (7), valve group six (6), valve group eleven (11), and valve group thirteen (13), thereby achieving the operating condition in which the high-temperature economizer flows downstream into the boiler drum (27) through branch pipe two (15) and branch pipe three (16); The method of supplying water from the water main pipe (18) to the economizer or the boiler drum (27) includes: a method in which the water main pipe (18) supplies water to the economizer starting from the low-temperature economizer alone, a method in which the water main pipe (18) supplies water to the economizer starting from the high-temperature economizer alone, a method in which the water main pipe (18) supplies water to each economizer starting from the low-temperature economizer and the high-temperature economizer at the same time, and an operating condition in which the water main pipe (18) directly supplies water to the boiler drum (27) through the branch pipe 1 (14).

2. A method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: The invention also includes a working method for freely isolating a high-temperature economizer and a low-temperature economizer: closing valve group one (1), valve group two (2), valve group three (3), and valve group four (4) to realize a completely isolated working condition of the low-temperature economizer; closing valve group five (5), valve group six (6), valve group seven (7), and valve group eight (8) to realize a completely isolated working condition of the high-temperature economizer; opening valve group nine (9) and valve group ten (10), closing valve group one (1), valve group three (3), valve group five (5), valve group seven (7), valve group two (2), valve group four (4), valve group twelve (12), valve group six (6), and valve group eight (8) to realize a simultaneously isolated working condition of the high-temperature economizer and the low-temperature economizer, that is, the feed water is no longer heated by the economizer but directly enters the boiler drum through branch pipe one (14).

3. A method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: It also includes the combined operating conditions of the parallel system: in the operating conditions of each group of economizers operating in the forward or reverse flow, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum (27), the operating conditions of the low-temperature economizer cocurrently entering the boiler drum (27), the operating conditions of the high-temperature economizer countercurrently entering the boiler drum (27) and the operating conditions of the high-temperature economizer cocurrently entering the boiler drum (27) can be freely combined into: the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer countercurrently entering the boiler drum (27) in parallel, the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer cocurrently entering the boiler drum (27) in parallel, the operating conditions of the low-temperature economizer cocurrently and the high-temperature economizer countercurrently entering the boiler drum (27) in parallel, and the operating conditions of the low-temperature economizer cocurrently and the high-temperature economizer cocurrently entering the boiler drum (27) in parallel.

4. A method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: It also includes combined operating conditions of the series system; in the operating conditions of each group of economizers operating in the forward or reverse flow, the operating conditions of the low-temperature economizer countercurrently entering the boiler drum (27), the operating conditions of the low-temperature economizer concurrently entering the boiler drum (27), the operating conditions of the high-temperature economizer countercurrently entering the boiler drum (27), and the operating conditions of the high-temperature economizer concurrently entering the boiler drum (27) can be freely combined into: the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer countercurrently entering the boiler drum (27) in series, the operating conditions of the low-temperature economizer countercurrently and the high-temperature economizer concurrently entering the boiler drum (27) in series, the operating conditions of the low-temperature economizer concurrently and the high-temperature economizer concurrently entering the boiler drum (27) in series, and the operating conditions of the low-temperature economizer concurrently and the high-temperature economizer concurrently entering the boiler drum (27) in series.

5. The method for adjusting boiler load and flue gas temperature according to claim 3, characterized in that: The water supply main (18) supplies water to the economizers from both the low-temperature economizer and the high-temperature economizer at the same time.

6. A method for adjusting boiler load and flue gas temperature according to claim 4, characterized in that: The water supply main pipe (18) starts to supply water from the low-temperature economizer, flows from the low-temperature economizer through the high-temperature economizer and then enters the boiler drum (27) under the operating conditions; the water supply main pipe (18) starts to supply water from the high-temperature economizer, flows from the high-temperature economizer through the low-temperature economizer and then enters the boiler drum (27) under the operating conditions.

7. The method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: Valve group 1 (1), valve group 2 (2), valve group 3 (3), valve group 4 (4), valve group 5 (5), valve group 6 (6), valve group 7 (7), valve group 8 (8), valve group 9 (9), valve group 10 (10), valve group 11 (11), valve group 12 (12) and valve group 13 (13) use electric or pneumatic valves with regulating functions.

8. The method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: The working medium flow rate in the corresponding economizer heating surface is adjusted by adjusting the opening degree of valve group 1 (1), valve group 2 (2), valve group 3 (3), valve group 4 (4), valve group 5 (5), valve group 6 (6), valve group 7 (7) and valve group 8 (8) at the economizer header end respectively.

9. The method for adjusting boiler load and flue gas temperature according to claim 1, characterized in that: The flow of working medium in the branch pipe and the economizer heating surface is adjusted by adjusting the opening degree of valve group nine (9) on branch pipe one (14), valve group eleven (11) on branch pipe two (15), valve group thirteen (13) on branch pipe three (16) and valve group twelve (12) on branch pipe four (17).

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