A multi-tube separator for the lower exhaust gas of a circulating fluidized bed boiler using low calorific value fuel

Abstract

A multi-tube separator for the lower exhaust of a circulating fluidized bed boiler fueled by low calorific value fuel comprises a plurality of separators arranged side by side, wherein a single separator comprises a separator outer tube, wherein the separator outer tube consists of an inlet section, a separation section and an outlet section, wherein the inlet section is provided with spiral blades and a flow-averaging inner core, wherein the separation section is provided with a conical shutter to form a separation structure in which both the inner ring and the outer ring are shutters, wherein the outlet section is provided with an anti-wear sleeve, and an anti-cross-gas baffle is provided between the inlet sections of two adjacent separators, and an air outlet pipe is provided at the bottom of each separator.

Description

Technical Field

[0001] The invention relates to an auxiliary device of a fluidized bed boiler, in particular to a lower exhaust multi-tube separator of a circulating fluidized bed boiler with a low calorific value fuel. Background Art

[0002] Circulating fluidized bed boilers are now fully developed because of their low-temperature oxygen-deficient combustion and compliance with environmental protection requirements. At the same time, circulating fluidized bed boilers have a wide range of fuel adaptability. For fuels with low calorific value or high volatility that are easy to burn out, the combined two-stage separation system often uses a medium-low temperature lower exhaust multi-tube separator to separate the return system. In boiler reconstruction, because the lower exhaust multi-tube separator can handle a larger amount of flue gas, due to structural limitations, the lower exhaust multi-tube separator is often used, such as Figure 1 However Figure 1 The dust-laden airflow inlet section of the separator shown above adopts a single or double helix structure, which has large resistance and is easy to wear. In addition, the separator lacks a flow-averaging section, and the separation section also has no inner core, and the separation efficiency is as low as 40-50%. In addition, the outer cylinder of the separator is easily worn and perforated, which affects the normal operation of the boiler. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a multi-tube separator for the lower exhaust of a circulating fluidized bed boiler with low calorific value fuel, which has low resistance and is not easy to wear, has a stabilizing effect on the rotating airflow, and can improve the separation efficiency.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a multi-tube separator for the lower exhaust of a circulating fluidized bed boiler with low calorific value (700-1600kcal / kg) fuel, comprising a plurality of separators arranged side by side, a single separator comprising a separator outer tube, the separator outer tube consisting of an inlet section, a separation section and an outlet section, the inlet section is provided with spiral blades and a flow-averaging inner core, the separation section is provided with a conical shutter to form a separation structure in which both the inner ring and the outer ring are shutters, the outlet section is provided with an anti-wear sleeve, adjacent separators are provided with an anti-cross-gas baffle between the inlet sections, and an outlet pipe is provided at the bottom of each separator.

[0005] Furthermore, the spiral blades are petal-type spiral blades.

[0006] Furthermore, a plurality of separators are fixed on the top of the ash bin through support beams.

[0007] After the dust-laden airflow passes through the separator, the purified airflow is discharged from the outlet pipe, and the separated dust particles are collected on the bottom plate of the ash bin and discharged downward.

[0008] The present invention installs petal-shaped spiral blades inside the inlet section of the separator outer cylinder. Compared with single or double spiral structures, the climbing angle remains unchanged and the cyclone effect is the same; but the resistance is reduced and it is not easy to wear; the flow-averaging inner core has a stabilizing effect on the rotating airflow.

[0009] The present invention installs a conical shutter inside the separation section of the separator outer cylinder to form a separation structure in which both the inner ring and the outer ring are shutters. Some of the dust particles separated and close to the edge are discharged from the cylinder in time through the outer shutter without further abrasion of the inside. When the airflow passes through the inner shutter, the separation effect is increased due to the return.

[0010] The invention can process a larger amount of flue gas, has small separator resistance, high separation efficiency and light wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a spiral structured lower exhaust multi-tube separator in the prior art;

[0012] Figure 2 for Figure 1 Schematic diagram of the structure of a single separator;

[0013] Figure 3 A schematic structural diagram of a single separator in an embodiment of the present invention;

[0014] Figure 4 for Figure 3 Middle AA view;

[0015] Figure 5 It is a schematic diagram of the overall structure of an embodiment of the lower exhaust multi-tube separator of the present invention.

[0016] In the figure: 1. separator outer cylinder, 101. inlet section, 102. separation section, 103. outlet section, 2. petal-shaped spiral blades, 3. flow-equalizing inner core, 4. conical shutters, 5. anti-wear sleeve, 6. anti-cross-gas baffle, 7. support beam, 8. outlet pipe, 9. ash bin, 10. bottom plate. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 3-5As shown, the multi-tube separator in this embodiment includes three separators arranged side by side, and a single separator includes a separator outer tube 1, which is composed of an inlet section 101, a separation section 102 and an outlet section 103. The inlet section 101 is provided with a petal-shaped spiral blade 2 and a flow-averaging inner core 3, the separation section 102 is provided with a conical shutter 4, and the outlet section 103 is provided with an anti-wear sleeve 5. Adjacent separators are provided with an anti-cross-gas baffle 6 between the inlet sections, and an outlet pipe 8 is provided at the bottom of each separator. After the dust-laden airflow passes through the separator, the purified airflow is discharged from the outlet pipe 8, and the separated dust particles are collected on the bottom plate 10 of the ash bin 9 and discharged downward.

[0019] Conical shutters 4 are installed inside the separation section 102 of the separator outer tube 1, forming a separation structure in which both the inner ring and the outer ring are shutters.

[0020] Application Example 1: Taking a gangue washing power plant as an example, a 40-ton power generation boiler is installed using the above technology, and the rear-stage separation adopts this lower exhaust multi-tube separator suitable for circulating fluidized bed boilers with low calorific value fuels above 700kcal / kg. When the actual operation of the gangue calorific value is 1000-1200kcal / kg, the multi-tube separator does not need to return the material; when the actual operation of the gangue calorific value is 1200-1400kcal / kg, the multi-tube separator partially returns the material (<50%). The boiler burns stably, and all parameters meet the design requirements. The bed temperature can be stabilized at 850℃-920℃, the fly ash carbon content is 1-3%, the slag carbon content is 0.5-2%, the exhaust temperature is 130-140℃, and the original emission of NO without flue gas fluidization is 0. X At 250 mg / m 3 Below, the original emission NO of flue gasification X At 150 mg / m 3 the following.

[0021] Application Example 2: Taking a 75-ton boiler of a coal gangue thermal power company as an example, the lower exhaust multi-tube separator suitable for low calorific value fuel circulating fluidized bed boilers is used in the biomass tail shaft of the boiler (the multi-tube separator in front of the bag is adjusted to be arranged in front of the SCR catalyst), and the separated coarse ash is directly sent to the ash bin. Because of the separation effect of the multi-tube separator on coarse ash, the influence of catalyst ash accumulation and alkali metal poisoning on the SCR catalyst is reduced; at the same time, the air preheater and bag are protected.

[0022] The working process of the present invention is as follows: the dust-laden airflow passes through each separator in the multi-tube separator, and becomes a rotating airflow after passing through the petal-shaped spiral blades 2 in the separator. The particles in the airflow are thrown toward the cylinder wall due to the centrifugal force. The airflow goes downward, and the particles flow out along the gaps in the cylinder wall of the conical louver 4 without further abrasion of the interior; the clean airflow further separates the particles when passing through the conical louver 4, and the particles sink and are discharged; the airflow is discharged through the outlet pipe 8 in the ash bin 9. The lower exhaust multi-tube separator can handle a larger amount of flue gas, with small separator resistance, high separation efficiency, and light wear. It can be used as a certain stage in a two-stage combined separation system.

[0023] Those skilled in the art may make various modifications and variations to the present invention. If these modifications and variations are within the scope of the claims of the present invention and their equivalents, then these modifications and variations are also within the protection scope of the present invention.

[0024] The contents not described in detail in the specification are prior art known to those skilled in the art.

Claims

1. A multi-tube separator for lower exhaust of a circulating fluidized bed boiler with low calorific value fuel, comprising a plurality of separators arranged side by side, characterized in that: A single separator includes a separator outer cylinder, which is composed of an inlet section, a separation section and an outlet section. The inlet section is provided with spiral blades and a flow-balancing inner core, the separation section is provided with a conical shutter, and the outlet section is provided with an anti-wear sleeve. Adjacent separators are provided with anti-cross-flow baffles between the inlet sections, and an outlet pipe is provided at the bottom of each separator.

2. The lower exhaust multi-tube separator of the circulating fluidized bed boiler with low calorific value fuel according to claim 1 is characterized in that: The spiral blades are petal-type spiral blades.

3. The lower exhaust multi-tube separator of the circulating fluidized bed boiler with low calorific value fuel according to claim 1 or 2, characterized in that: Multiple separators are fixed on the top of the ash silo by support beams.

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