Low-temperature economizer capable of removing accumulated dust through flow limiting and speed increasing

Abstract

The utility model belongs to the technical field of low-temperature coal economizers of coal-fired units, and particularly relates to a low-temperature coal economizer capable of removing accumulated dust through flow limiting and speed increasing, which comprises a shell, a flue gas inlet pipeline, a flue gas horizontal pipeline, a flue gas outlet pipeline, a condensate water inlet pipeline, a condensate water outlet pipeline, a heat exchange pipe, fins, a partition plate, an adjustable baffle and a valve. The horizontal flue gas pipeline is divided into four channels with the same flow area, the channels are isolated from one another and are not communicated with one another, the length of the partition plates is arranged from head to tail in the horizontal direction of the horizontal flue, and an adjustable baffle is arranged at an inlet of each independent channel. According to the low-temperature economizer capable of removing accumulated ash through flow limiting and speed increasing, the smoke flow speed is increased by limiting the smoke flow area, the retention time of blocking substances in the low-temperature economizer can be shortened by increasing the smoke flow speed, and therefore blocking of the low-temperature economizer is reduced, automatic ash removing of the low-temperature economizer is achieved, and meanwhile after the blocking condition is improved, the ash removing efficiency is improved. The heat exchange efficiency of the low-temperature economizer is improved, and the equipment stability is better.

Description

Technical Field

[0001] The utility model relates to the technical field of low-temperature economizers for coal-fired units, in particular to a low-temperature economizer which can remove ash accumulation by limiting current and increasing speed. Background Art

[0002] Boiler exhaust loss is the biggest loss of boilers. The exhaust temperature is high and has not been fully utilized. Therefore, many thermal power units now have added low-temperature economizers, which heat the low-temperature condensate through the flue gas in the tail flue. After the flue temperature is reduced, the flue gas volume decreases accordingly, and the smoke dust resistivity also decreases accordingly, realizing the recovery of flue gas waste heat and reducing the unit's coal consumption for power generation. At the same time, the low-temperature economizer heats the condensate, increases the temperature of the condensate, and can improve the turbine's work capacity. The low-temperature economizer is arranged on the horizontal flue after the air preheater and before the electrostatic precipitator.

[0003] In actual operation, there is a situation where the heat exchange surface of the low-temperature economizer is blocked, which causes the resistance of the flue gas system to increase, and the unit is forced to limit load or shut down, seriously affecting the safe and economical operation of the unit. There are two common reasons for the blockage of the heat exchange surface of the low-temperature economizer:

[0004] First, the denitrification system sprays ammonia unevenly or too much ammonia, which causes an increase in the amount of ammonia carried by the local flue gas. Ammonia reacts with sulfur trioxide and water in the flue gas to form ammonium bisulfate. The melting point of ammonium bisulfate is 147°C. Ammonium bisulfate is very sticky in liquid form and easily adheres to the surface of the heat exchange tubes and fins of the low-temperature economizer, and absorbs fly ash in the flue gas, causing blockage of the heat exchange channel.

[0005] Second, the flue gas flow field is uneven. For example, if the flue gas guide plate is not designed properly, the flue gas flow field will be uneven, the local flue gas velocity will be differentiated, and the fly ash and smoke carried by the slow-flowing flue gas will easily settle on the heat exchange surface of the low-temperature economizer, causing blockage.

[0006] Once local blockage occurs, if effective measures are not taken, the blockage will gradually worsen, causing a significant increase in the flue gas side differential pressure. The optimization of the flue flow field is relatively difficult to implement due to the limitations of the transformation plan and the maintenance period. It is imperative to carry out online blockage treatment of low-temperature economizers under the existing equipment. Utility Model Content

[0007] The utility model aims to provide a low-temperature economizer which can remove ash accumulation by limiting flow and increasing speed, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a low-temperature economizer for removing ash accumulation by limiting flow and increasing speed, comprising a shell, a flue gas inlet pipe, a flue gas horizontal pipe, a flue gas outlet pipe, a condensate inlet pipe, a condensate outlet pipe, a heat exchange tube, a fin, a partition one, a partition two, a partition three, an adjustable baffle one, an adjustable baffle two, an adjustable baffle three, an adjustable baffle four, a valve one, a valve two, a valve three and a valve four, the horizontal flue gas pipe is divided into four channels with the same flow area, each channel is isolated from each other and does not communicate with each other, and the length of the partition is arranged from beginning to end along the horizontal direction of the horizontal flue.

[0009] An adjustable baffle is provided at the entrance of each individual channel, and the smoke flow of each channel is controlled by switching the adjustable baffle.

[0010] Preferably, the valve one, valve two, valve three and valve four function to adjust the opening and closing of adjustable baffle one, adjustable baffle two, adjustable baffle three and adjustable baffle four.

[0011] Preferably, the adjustable baffles are closed in sequence respectively, so as to reduce the blockage of the low-temperature economizer by periodically reducing the flue gas flow area, increasing the flue gas flow rate, and reducing the residence time of easily deposited dust and other clogging materials in the low-temperature economizer.

[0012] Preferably, the horizontal flue of the low-temperature economizer is divided into four channels, and the actual number of partitions is determined according to the size of the low-temperature economizer.

[0013] Preferably, the adjustable baffle 1, the adjustable baffle 2, the adjustable baffle 3, and the adjustable baffle 4 are not limited in form, and any baffle type that can adjust the flow area is possible.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. The low-temperature economizer can remove ash by limiting the flow and increasing the speed. The flue gas flow rate is increased by limiting the flue gas flow area. The faster flue gas flow rate can reduce the residence time of the blocking material in the low-temperature economizer, thereby reducing the blockage of the low-temperature economizer and realizing automatic cleaning of the low-temperature economizer. At the same time, after the blockage situation is improved, the heat exchange efficiency of the low-temperature economizer is improved, and the equipment stability is better.

[0016] 2. The low-temperature economizer which removes ash accumulation by limiting flow and increasing speed divides the traditional horizontal flue of the low-temperature economizer into several separate flues, and adjusts the flow area of ​​the flue gas by switching the adjustable baffle at the inlet. The adjustable baffles are closed in sequence to reduce the flow area and increase the flue gas flow rate. The faster flue gas flow rate can reduce the residence time of clogging materials in the low-temperature economizer, remove ammonium bisulfate and ash accumulation on the surface of the heat exchange tube in real time, and ensure the continuous cleaning of the surface of the heat exchange tube, thereby achieving the purpose of controlling ash blockage, realizing online automatic ash cleaning of the low-temperature economizer, and greatly improving the heat exchange efficiency of the low-temperature economizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a top view of the low-temperature economizer system of the utility model.

[0018] In the figure: 1. shell; 2. flue gas inlet pipe; 3. flue gas horizontal pipe; 4. flue gas outlet pipe; 5. condensate water inlet pipe; 6. condensate water outlet pipe; 7. heat exchange tube; 8. fin; 91. partition one; 92. partition two; 93. partition three; 101. adjustable baffle one; 102. adjustable baffle two; 103. adjustable baffle three; 104. adjustable baffle four; 111. valve one; 112. valve two; 113. valve three; 114. valve four. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] See also Figure 1 The utility model provides a technical solution: a low-temperature economizer for removing ash accumulation by limiting flow and increasing speed, comprising a shell 1, a flue gas inlet pipe 2, a flue gas horizontal pipe 3, a flue gas outlet pipe 4, a condensate inlet pipe 5, a condensate outlet pipe 6, a heat exchange tube 7, a fin 8, a partition 1 91, a partition 2 92, a partition 3 93, an adjustable baffle 1 101, an adjustable baffle 2 102, an adjustable baffle 3 103, an adjustable baffle 4 104, a valve 1 111, a valve 2 112, a valve 3 113 and a valve 4 114, the flue gas horizontal pipe 3 is divided into four channels with the same flow area, each channel is isolated from each other and does not communicate with each other, and the length of the partition is arranged from beginning to end along the horizontal direction of the horizontal flue.

[0021] An adjustable baffle is provided at the entrance of each individual channel, and the smoke flow of each channel is controlled by switching the adjustable baffle.

[0022] The valve one 111 , the valve two 112 , the valve three 113 and the valve four 114 are used to adjust the opening and closing of the adjustable baffle one 101 , the adjustable baffle two 102 , the adjustable baffle three 103 and the adjustable baffle four 104 .

[0023] Close the adjustable dampers in sequence to periodically reduce the flue gas flow area, increase the flue gas flow rate, and reduce the residence time of easily deposited dust and other clogging materials in the low-temperature economizer, thereby reducing the clogging of the low-temperature economizer.

[0024] The adjustable baffle 1 101 , the adjustable baffle 2 102 , the adjustable baffle 3 103 , and the adjustable baffle 4 104 may be in any form, and any baffle type that can adjust the flow area is acceptable.

[0025] The horizontal flue of the low-temperature economizer is divided into four channels, and the actual number of partitions is determined according to the size of the low-temperature economizer.

[0026] Working principle:

[0027] Generally, the flue gas enters the flue gas horizontal pipe 3 through the flue gas inlet pipe 2, and the condensed water enters the heat exchange tube 7 through the condensed water inlet pipe 5. The flue gas transfers heat to the fins 8 around the heat exchange tube 7, and the flue gas temperature decreases. The heat is absorbed by the condensed water in the heat exchange tube 7 and the temperature is increased.

[0028] The horizontal flue gas duct 3 is divided into four channels of the same area by partition 1 91, partition 2 92 and partition 3 93. Each channel is isolated from each other and does not communicate with each other. The length of the partition is arranged from the beginning to the end along the horizontal flue direction. Adjustable baffle 1 101, adjustable baffle 2 102, adjustable baffle 3 103 and adjustable baffle 4 104 are respectively arranged at the entrance of each individual channel. The flue gas flow of each channel is controlled by switching the adjustable baffle 1 101, adjustable baffle 2 102, adjustable baffle 3 103 and adjustable baffle 4 104. The switching of adjustable baffle 1 101, adjustable baffle 2 102, adjustable baffle 3 103 and adjustable baffle 4 104 is controlled by valve 1 111, valve 2 112, valve 3 113 and valve 4 114.

[0029] When the unit is running at a lower load, the adjustable damper 101 is closed, and the smoke in this area is blocked. The adjustable dampers 2 102, 3 103, and 4 104 remain open, and the smoke can continue to pass through. Figure 1 As shown, the flue gas flow area is reduced and the flue gas flow rate is increased, which can reduce the residence time of easily deposited dust and other clogging materials in the low-temperature economizer, thereby reducing the clogging of the low-temperature economizer.

[0030] Close the adjustable baffle 2 102 in sequence, open the adjustable baffle 1 101, the adjustable baffle 3 103, and the adjustable baffle 4 104, and repeat the above cleaning steps. Close the adjustable baffle 3 103, open the adjustable baffle 1 101, the adjustable baffle 2 102, and the adjustable baffle 4 104, and repeat the above cleaning steps. Close the adjustable baffle 4 104, open the adjustable baffle 1 101, the adjustable baffle 2 102, and the adjustable baffle 3 103, and repeat the above cleaning steps.

[0031] The above is the method for removing dust accumulation online in the low-temperature economizer of the utility model. By periodically reducing the flue gas circulation area, increasing the flue gas flow rate, and reducing the residence time of easily deposited dust and other clogging materials in the low-temperature economizer, the blockage of the low-temperature economizer is reduced.

[0032] The method involved in the utility model is not limited to dividing the horizontal flue of the low-temperature economizer into four channels, but the actual number of partitions is determined according to the size of the low-temperature economizer.

[0033] The form of the adjustable baffle in the above embodiments is not limited, and all baffle types that can adjust the flow area are within the scope of protection of this utility model.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A low-temperature economizer for removing ash accumulation by limiting flow and increasing speed, comprising a shell (1), a flue gas inlet pipe (2), a flue gas horizontal pipe (3), a flue gas outlet pipe (4), a condensate water inlet pipe (5), a condensate water outlet pipe (6), a heat exchange tube (7), a fin (8), a baffle plate 1 (91), a baffle plate 2 (92), a baffle plate 3 (93), an adjustable baffle plate 1 (101), an adjustable baffle plate 2 (102), an adjustable baffle plate 3 (103), an adjustable baffle plate 4 (104), a valve 1 (111), a valve 2 (112), a valve 3 (113) and a valve 4 (114), characterized in that: The horizontal flue gas duct (3) is divided into four channels with the same flow area, each channel is isolated from each other and does not communicate with each other, and the length of the partition is arranged from the beginning to the end along the horizontal direction of the horizontal flue; An adjustable baffle is provided at the entrance of each individual channel, and the smoke flow of each channel is controlled by switching the adjustable baffle.

2. A low-temperature economizer for removing ash deposits by limiting current and increasing speed according to claim 1, characterized in that: The valve one (111), valve two (112), valve three (113) and valve four (114) are used to adjust the opening and closing of the adjustable baffle one (101), the adjustable baffle two (102), the adjustable baffle three (103) and the adjustable baffle four (104).

3. A low-temperature economizer for removing ash accumulation by limiting current and increasing speed according to claim 1, characterized in that: The horizontal flue of the low-temperature economizer is divided into four channels, and the actual number of partitions is determined according to the size of the low-temperature economizer.

4. A low-temperature economizer for removing ash accumulation by limiting current and increasing speed according to claim 1, characterized in that: The adjustable baffle 1 (101), the adjustable baffle 2 (102), the adjustable baffle 3 (103), and the adjustable baffle 4 (104) are not limited in form, and any baffle type that can adjust the flow area is acceptable.

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