阅读说明：本技术 一种低二氧化碳排放的燃煤锅炉及燃烧方法 (Coal-fired boiler with low carbon dioxide emission and combustion method ) 是由 李谦 李秋实 罗业富 任耕北 于 2021-09-26 设计创作，主要内容包括：一种低二氧化碳排放的燃煤锅炉及燃烧方法,所述锅炉包括炉体,炉体上设置有底部进风口、排风口、燃烧供风区和燃尽供风区,燃烧供风区、燃尽供风区的对角进风口向炉体内供风形成切圆风场,还包括位于所述燃尽供风区上方的下沉供风区,下沉供风区用于向炉体中心喷射下沉气流,下沉气流穿过所述切圆风场的中心无风区下沉至锅炉底部与底部上升气流混合。本发明产生的下沉气流在燃尽供风区上方形成阻挡,同时,下沉气流由中心无风区下沉,与底部上升气流结合形成循环气流,增加了排放物、煤炭、氧气的接触时间,使得各物质的反应更加充分,燃料的燃尽率明显提高、降低了燃煤成本,减少烟尘中的固体颗粒杂质,降低CO-(2)、SO-(2)、NO-(X)的气体排放物的排放量。(A coal-fired boiler with low carbon dioxide emission and a combustion method are provided, the boiler comprises a boiler body, a bottom air inlet, an air outlet, a combustion air supply area and a burnout air supply area are arranged on the boiler body, the opposite angle air inlets of the combustion air supply area and the burnout air supply area supply air into the boiler body to form a tangential air field, the boiler further comprises a sinking air supply area located above the burnout air supply area, the sinking air supply area is used for spraying sinking air flow to the center of the boiler body, and the sinking air flow passes through a central no-wind area of the tangential air field and sinks to the bottom of the boiler to be mixed with rising air flow at the bottom. The generated sinking airflow forms a barrier above the over-fire air supply area, meanwhile, the sinking airflow sinks from the central windless area and is combined with the bottom ascending airflow to form circulating airflow, so that the contact time of emissions, coal and oxygen is increased, the reaction of all substances is more sufficient, and the fuel is more fuelThe burnout rate is obviously improved, the coal burning cost is reduced, solid particle impurities in smoke dust are reduced, and CO is reduced 2 、SO 2 、NO X The amount of gaseous emissions of (c).)

1. The utility model provides a coal fired boiler that low carbon dioxide discharged, includes furnace body (1), be provided with bottom air intake (2), air exit (3), burning air supply district (5) and burn out air supply district (6) on furnace body (1), the diagonal angle air intake (14) of burning out air supply district (5), burn out air supply district (6) form tangent circle wind field to furnace body (1) interior air feed, its characterized in that still including being located burn out air supply district (6) top sink air supply district (10), sink air supply district (10) are used for spraying sunken air current (11) to furnace body (1) center, sink air current (11) pass the central no wind district (17) of tangent circle wind field sinks to the boiler bottom and rises air current (12) and mix with the bottom.

2. The coal-fired boiler with low carbon dioxide emission according to claim 1, characterized in that the sinking air supply zone (10) comprises a first air supply pipe (15) installed on the inner wall of the furnace body (1), the first air supply pipe (15) comprises a pipe body (161), a plurality of nozzles (18) are detachably arranged on the pipe body (161), and the nozzles (18) face the central airless zone (17).

3. The coal-fired boiler with low carbon dioxide emission according to claim 2, characterized in that the air outlet end of the nozzle (18) on the first air supply pipe (15) is inclined downwards by 5-15 °.

4. The coal-fired boiler with low carbon dioxide emission according to claim 2, characterized in that the air supply volume of the sinking air supply zone (10) is 10-20% of the total air volume entering the furnace body (1).

5. The coal-fired boiler with low carbon dioxide emission according to claim 1, characterized in that the furnace body (1) is further provided with a lower air supply area (7) and a middle air supply area (8), the lower air supply area (7) is located below the combustion air supply area (5), the middle air supply area (8) is located between the combustion air supply area (5) and the burnout air supply area (6), the lower air supply area (7) and the middle air supply area (8) comprise at least one set of air supply components, each air supply component comprises a diagonal air inlet (14), each diagonal air inlet (14) is used for supplying air into the furnace body (1) to form a tangential wind field, a second air supply pipe (16) is arranged between two adjacent diagonal air inlets (14), and each second air supply pipe (16) is used for supplying air to the tangential wind field;

the air supply rate of the middle air supply zone (8) is 25-35% of the total air supply rate entering the furnace body (1), and the air supply rate of the lower air supply zone (7) is 5-10% of the total air supply rate entering the furnace body (1).

6. The coal-fired boiler with low carbon dioxide emission according to claim 5, characterized in that the second air supply pipe (16) comprises a pipe body (161), the pipe body (161) is provided with an air inlet (162) and a plurality of air outlets (163) distributed along the axial direction of the pipe body (161), the air inlet (162) is located at the end of the second air supply pipe (16), and the air inlets (162) of two adjacent second air supply pipes (16) are close to different diagonal air inlets (14).

7. The coal-fired boiler with low carbon dioxide emission according to claim 5, characterized in that an upper air supply area (9) is arranged between the burnout air supply area (6) and the sinking air supply area (10), the upper air supply area (9) comprises at least one set of air supply components, and the air supply volume of the upper air supply area (9) is greater than that of the lower air supply area (7) and smaller than that of the middle air supply area (8).

8. The coal-fired boiler with low carbon dioxide emission according to any one of claims 2 to 7, characterized in that a perlite layer (164) is laid on the tube body (161) of the first air supply tube (15) or the second air supply tube (16), and the outer surface of the perlite layer (164) is covered with ceramic fiber cloth (165).

9. The coal-fired boiler with low carbon dioxide emission according to claim 8, wherein the air outlet (163) of the first air supply pipe (15) and the second air supply pipe (16) is detachably connected with a nozzle (18), the nozzle (18) comprises a nozzle main body (181), a spiral groove (182) which extends spirally along the inner wall of the nozzle main body (181) is arranged in the nozzle main body (181), a partition plate (185) is arranged in the nozzle main body (181), the partition plate (185) divides the inner space of the nozzle main body (181) into an air inlet area communicated with the air inlet end and a cyclone area communicated with the air outlet end, a chamfer hole (186) communicated with the air inlet area and the cyclone area is arranged on the partition plate (185), an included angle is formed between the central axis of the chamfer hole (186) and the central axis of the partition plate (185), and at least one rotation assisting pipe (184) is arranged on the nozzle main body (181), the inside of the rotation assisting pipe (184) forms a rotation assisting air passage, one end of the rotation assisting air passage is communicated with the air inlet area, and the other end of the rotation assisting air passage is communicated with the cyclone area.

10. A low carbon dioxide emission combustion method, characterized in that the coal-fired boiler of any one of claims 1 to 9 is used, and the method comprises the following steps:

the opposite angle air inlets (14) of the combustion air supply area (5) and the burnout air supply area (6) input mixed air flow of air and coal powder into the furnace body (1) to form a tangential circular air field;

the bottom ascending air flow (12) enters the furnace body (1) from the bottom air inlet (2), and the bottom ascending air flow (12) vertically and upwards moves to the air outlet (3) through tangential air fields corresponding to the combustion air supply area (5) and the burnout air supply area (6);

the sinking air flow (11) passes through the central airless area (17) of the tangential circular wind field and sinks to the bottom of the boiler to be mixed with the ascending air flow at the bottom.

Technical Field

The invention relates to the technical field of boiler combustion, in particular to a coal-fired boiler capable of reducing discharge of smoke, carbon dioxide and other emissions and a combustion method.

Background

With the rapid development of national economy, the energy consumption of China is increasing day by day and becomes a world large energy consumption country. In the total primary energy consumption of China, coal consumption is in absolute dominance and approximately accounts for seven elements of the total energy consumption.

Coal plays an important role in China as an important energy source, but meanwhile, the coal burning also causes serious pollution to the environment. Carbon dioxide and nitrogen oxides are gases that can cause serious pollution to the atmosphere environment, and are basically considered as one of the main sources of atmospheric pollution. At present, the biggest characteristic of energy composition in China is that coal is taken as a main raw material, and a large amount of carbon dioxide and nitric oxide gas are generated, so that the energy structure has negative effects on economic and efficient growth and ecological environment.

With the national higher and higher requirements for environmental emission, low-emission combustion technology and post-treatment technology have been widely applied to various boilers and burners. Patent CN102692013B discloses a tangential combustion system under air staged combustion technology, which provides an integrated air staging method and staged tangential combustion method. As shown in figure 1, in the prior art, a relatively small tangential edge is formed by utilizing the opposite-angle primary air and pulverized coal mixed air flow 102 through opposite impact, and secondary air such as offset cyclone air, edge folding air and the like is combined to enable flow fields of cross sections of a combustion layer 207 and a burnout layer 206 of a boiler to be in a tangential circle combustion state as shown in figure 2, so that coking and corrosion of a furnace wall are controlled. However, the wind field formed by the tangential firing technology has a strong wind area 103, a weak wind area 104 and a no wind area 105, so that the oxygen supply is unreasonableInsufficient oxygen supply, short contact time and insufficient combustion of coal, so that the total cardinal number of generated carbon dioxide and other emissions is large; meanwhile, unburned coal is driven by the bottom air inlet to be continuously discharged to tail gas treatment equipment through the discharge port, and the tail gas treatment pressure and cost are increased. Therefore, the existing coal-fired boiler can not effectively reduce smoke dust and CO₂、SO₂、NO_XAnd (4) discharging.

Disclosure of Invention

The invention aims to provide a coal-fired boiler with low carbon dioxide emission and a combustion method, wherein an air supply pipe of a top sinking type air supply area is utilized to continuously spray air flow to the center of a hearth, the air flow and smoke dust and carbon dioxide of an ascending channel are in opposite impact to form an air curtain to block the smoke dust and CO₂、SO₂、NO_XWhen the emissions go upward, the emissions return back through a windless area in the center of the hearth and sink to a combustion layer to be mixed with coal to form secondary circulation combustion, so that the problems of high coal burning cost caused by insufficient coal burning, namely, discharge of the coal out of a boiler, and high post-treatment cost and high treatment load caused by large emission of carbon dioxide, smoke dust and other pollutant emissions in the prior art are solved.

The invention is realized by the following technical scheme:

the utility model provides a coal fired boiler of low carbon dioxide emission, includes the furnace body, be provided with bottom air intake, air exit, burning air supply district and burn out air supply district on the furnace body, the diagonal angle air intake in burning air supply district, burn out air supply district forms tangent circle wind field to the air supply in the furnace body, still including being located burn out the sunken air supply district of air supply district top, the air supply district that sinks is used for spraying sunken air current to the furnace body center, sunken air current passes the central no wind district of tangent circle wind field sinks to boiler bottom and the ascending air current in bottom mixes.

In the technical scheme, the coal-fired boiler comprises a boiler body, wherein an air inlet is formed in the bottom of the boiler body, and bottom ascending air flow enters the boiler body from the bottom air inlet and vertically and upwards moves in the boiler body. Four combustion air supply areas and four over-fire air supply areas are arranged along the opposite angles of the cross section of the hearthThe diagonal air inlet is used for providing mixed air flow of primary air and coal powder into the hearth, or further comprises secondary air such as offset cyclone, edge folding air, direct blowing air and the like, so that a stable tangential circular air field is formed. The ascending air flow passes through the tangential wind field in the ascending process, carries smoke dust and gas emissions obtained by combustion in the hearth to vertically move upwards, and finally is discharged out of the furnace through the air outlet at the top. Wherein the smoke dust mainly contains light oxide impurities and incompletely combusted coal particles, and the gas emission mainly contains CO generated in the combustion process₂、SO₂、NO_X。

In order to make the combustion reaction more sufficient, different from the prior art, a sinking air supply area is arranged above the over-fire air supply area. The sinking air supply area is used for spraying sinking air flow to the center of the furnace body. In some embodiments, the downwind may be a direct wind or a spiral wind. The sinking airflow sprayed to the center of the hearth has two functions. First, the sinking air flow is horizontal or approximately horizontal air flow, and is approximately vertical to the moving direction of the ascending air flow, so that an air curtain is formed above the burnout air supply area to reduce smoke dust and CO moving to the air outlet₂、SO₂、NO_XThe amount of emissions, etc.; secondly, under the influence of a tangential circular wind field, the center of the cross section of the hearth is a windless area with small wind volume, so that a cylindrical central windless area is formed in the center of the hearth, and after sinking airflow is sprayed to the center, partial smoke dust and CO can be driven₂、SO₂、NO_XThe discharged materials vertically move downwards along the central windless area to the bottom of the boiler, and contact with the ascending air flow at the bottom again to ascend to form a circulating air flow; during the sinking process, smoke and CO₂、SO₂、NO_XAfter the discharged materials pass through the burnout air supply zone and the combustion air supply zone again, the discharged materials are combusted with the supplied oxygen for the second time, thereby improving the burnout rate of the fuel, reducing solid particle impurities in the smoke dust and reducing CO₂、SO₂、NO_XThe amount of gaseous emissions of (a); taking carbon dioxide as an example, the rising carbon dioxide is acted by the sinking gas flow and contacts with coal again to generate carbon monoxide, the carbon monoxide and oxygen are fully combusted to generate carbon dioxide, and the generated carbon dioxide is also usedAnd continuously react with coal under the action of the ascending gas flow.

The sinking air flow generated by the sinking air supply area forms a barrier above the burnout air supply area to block smoke dust and CO to a certain extent₂、SO₂、NO_XWhen the emissions go upwards, the sinking air flow sinks from the central airless area and is combined with the ascending air flow at the bottom to form a circulating air flow, the circulating air flow conveys the emissions above the burnout air supply area to the bottom of the boiler, and in the sinking process, the emissions are combusted with oxygen and coal for the second time, so that the contact time of the emissions, the coal and the oxygen is increased, the reaction of all the substances is more sufficient, the burnout rate of the fuel is obviously improved, the coal burning cost is reduced, solid particle impurities in smoke dust are reduced, and CO is reduced₂、SO₂、NO_XThe treatment difficulty and the treatment load of the post-treatment process are reduced.

As a preferred embodiment of the sinking air supply area in the present invention, the sinking air supply area includes a first air supply pipe installed on an inner wall of the furnace body, the first air supply pipe includes a pipe body, a plurality of nozzles are detachably disposed on the pipe body, and the nozzles face the central airless area. In this technical scheme, first air feed pipe can set up on one side stove wall, also can set up on the multiaspect stove wall, both can set up a first air feed pipe on one side stove wall, also can set up many first air feed pipes. The air inlet of the first air supply pipe is communicated with an external air source, and the external air source is sprayed out through a plurality of nozzles arranged on the pipe body after entering the pipe body. Preferably, each furnace wall is provided with a first air supply pipe, and the number of nozzles, the positions of the nozzles and the air output of the first air supply pipes on each furnace wall are the same, so that the sinking air flow forms a uniform air curtain above the burnout air supply area and is continuously input into the central airless area. In one or more embodiments, the nozzle may be either a metal nozzle, such as 310 stainless steel, or a ceramic nozzle, such as alumina ceramic.

Further, the air outlet end of the nozzle on the first air supply pipe is inclined downwards by 5-15 degrees. The emergent direction of the airflow sprayed by the nozzles on the first air supply pipe can be a horizontal direction and can also be inclined downwards by a certain angle, but the inclined downwards angle is not too large, otherwise the airflow and the ascending airflow form obvious opposite impact, the airflow at the top of the hearth is disordered, and most of the sinking airflow cannot enter a central airless area. In the technical scheme, in order to promote the sinking air flow to form better obstruction to the rising emissions and simultaneously enable most of the sinking air flow to enter the central airless area, the included angle between the air flow emergent direction of the nozzle of the first air supply pipe and the horizontal plane is 5-15 degrees, and preferably 5-12 degrees.

Furthermore, the air supply quantity of the sinking air supply area is 10% -20% of the total air quantity entering the furnace body. The sinking airflow sprayed by the sinking air supply area enters the flame part on the combustion bin to form a stamping and turning-back force on the flame on the upper part, so that smoke dust and gas emissions of the ascending channel are blocked, and the smoke dust and the gas emissions sink and combust again, therefore, the air supply amount of the sinking air supply area is not suitable to be too small, otherwise, the air curtain is thin, the blocking effect is poor, the sinking airflow which can pass through the central airless area to reach the bottom is less, and effective circulating airflow is difficult to form; the air supply amount of the sinking air supply area is not too large, too large sinking air flow easily causes airflow accumulation at the top of the hearth, circulating airflow can be accelerated, the temperature of the bottom and the middle of the hearth is reduced, and the coal is not beneficial to full combustion. By combining the above influencing factors, in the technical scheme, the air supply quantity of the sinking air supply area is 10-20% of the total air quantity entering the furnace body.

As a preferred embodiment of the present invention, the furnace body is further provided with a lower air supply area and a middle air supply area, the lower air supply area is located below the combustion air supply area, the middle air supply area is located between the combustion air supply area and the burnout air supply area, the lower air supply area and the middle air supply area comprise at least one group of air supply assemblies, each air supply assembly comprises a diagonal air inlet, the diagonal air inlets are used for supplying air into the furnace body to form a tangential wind field, a second air supply pipe is arranged between two adjacent diagonal air inlets, and the second air supply pipe is used for supplying air to the tangential wind field; the air supply rate of the middle air supply area is 25% -35% of the total air supply rate entering the furnace body, and the air supply rate of the lower air supply area is 5% -10% of the total air supply rate entering the furnace body.

In the technical scheme, a lower air supply area positioned between a bottom air inlet and a combustion air supply area supplies air to the lower part of a combustion bin, the lower air supply area comprises at least one group of air supply assemblies, each air supply assembly comprises four diagonal air inlets, the four diagonal air inlets provide mixed airflow of primary air and pulverized coal into a hearth, or further comprises secondary air such as offset cyclone, edge folding air, direct blowing air and the like to form a stable tangential circular air field, one or more second air supply pipes are arranged between two adjacent diagonal air inlets, the second air supply pipe is used for distributing air to the tangential circular wind field, the lower air supply area increases the combination of the fuel surface area and oxygen and prolongs the contact time on one hand, and on the other hand increases the overflow amount of fuel combustible substances, blocks the ascending channel of waste particles with large dead weight to a certain extent and reduces the emission amount of the waste particles.

The middle air supply area between the combustion air supply area and the burnout air supply area is also provided with at least one group of air supply assemblies, the arrangement and arrangement modes of the air supply assemblies in the middle air supply area can be the same as or different from those in the lower air supply area, and for example, at least two second air supply pipes can be arranged between the adjacent diagonal air inlets. The air flow of the flame part in the middle air supply area entering the combustion bin directly reaches the flame center to form combustion-supporting force for the combustion flame, so that the combustion and the heat value of the flame are enhanced, the middle air supply area meets the oxygen supply requirement of the combustion flame, and the more uniform air flow impact of an air field can promote the secondary sufficient combustion of particles.

In the technical scheme, the air flow of the middle air supply area directly reaches the flame center for supporting combustion, and the temperature of the bottom of the boiler needs to be prevented from being influenced by the lower air supply area, so that the air volume of the middle air supply area is larger than that of the lower air supply area. Preferably, the air supply rate of the middle air supply zone is 25% -35% of the total air supply rate entering the furnace body, and further preferably 27% -32%; the air supply volume of the lower air supply area is 5% -10% of the total air volume entering the furnace body, and is further preferably 5% -8%.

Among this technical scheme, the second air feed pipe is steadily joined in marriage the wind to tangent circle wind field, not only can reduce the area in the weak wind district of tangent circle wind field, improve the homogeneity in wind field, the air current fullness of whole cross-section is better, especially be close to wall department, the air distribution of second air feed pipe separates high-temperature gas and wall resistance, flame has been reduced and has been washd to the wall, boiler wall ash and slagging scorification have been prevented effectively, and realized more rationally supplying oxygen, reduce the emission of emissions such as smoke and dust, carbon dioxide effectively.

In the technical scheme, according to the air supply condition of the furnace body, the combustion air supply area and the burnout air supply area can be provided with the second air supply pipe or not. Preferably, the combustion air supply area and the burnout air supply area are only provided with diagonal air inlets at opposite corners without a second air supply pipe.

As an optimal structure of the second air supply pipe, the second air supply pipe comprises a pipe body, an air inlet and a plurality of air outlets distributed along the axial direction of the pipe body are formed in the pipe body, the air inlet is located at the end part of the second air supply pipe, and the air inlets of two adjacent second air supply pipes are close to different diagonal air inlets.

The second air supply pipe is of a tubular structure, and an air inlet and a plurality of air outlets are formed in the pipe body. The air inlet is connected with an external air source, and the air outlet faces the inside of the hearth. The quantity, the interval, the size and the air outlet angle of the air outlets can be adjusted according to the design requirements of the boiler. The closer the air outlet is to the air inlet, the larger the air speed and the air quantity of air distribution under the condition that the size of the air outlet is the same, and the smaller the air speed and the air quantity are vice versa, so that the position of the air inlet on the pipe body can be adjusted according to the air supply area to which the air distribution pipe belongs. In the technical scheme, the air inlets are arranged at the end parts of the pipe body, so that the air speed and the air quantity of the air distribution are gradually reduced from one diagonal air inlet to the other diagonal air inlet, and then the air distribution is matched with a weak air area between the two diagonal air inlets, the area of which is gradually increased or gradually reduced, and the reinforcement of a wind field is realized. The stable tangential wind field is combined, so that the area of a weak wind area in front of the same furnace wall is always gradually reduced or increased along the clockwise direction or the anticlockwise direction, and therefore the air inlets of two adjacent air distribution pipes need to be close to different diagonal air inlets so as to realize uniform air distribution on each surface. It should be understood by those skilled in the art that, to realize air distribution, it is necessary to have a region with a larger area of the weak air region, and the air distribution amount is stronger, that is, the air inlet of the air distribution pipe is always close to the region with a larger area of the weak air region. Through the arrangement, the area of a weak wind area is remarkably reduced, the wind field in the boiler is more uniform, the air flow fullness of the whole cross section is better, particularly the air supply system is close to the wall surface, the flow is enhanced by the air supply system, high-temperature gas and the wall surface are separated, the erosion of flame to the wall surface is reduced, and the wall surface of the boiler is effectively prevented from being dusted and slagging.

Further, an upper air supply area is arranged between the burnout air supply area and the sinking air supply area, the upper air supply area comprises at least one group of air supply assemblies, and the air supply amount of the upper air supply area is more than that of the lower air supply area and is less than that of the middle air supply area. In the technical scheme, an upper air supply area is also arranged above the burnout air supply area, and horizontal or nearly horizontal air flow provided by the upper air supply area is used for preventing unburned coal from continuously rising to a certain degree or forming a backflow channel, so that the contact time of the coal and oxygen is further prolonged, and the coal in the furnace body is fully combusted.

Furthermore, an perlite layer is paved on the tube body of the first air supply tube or the second air supply tube, and ceramic fiber cloth covers the outer surface of the perlite layer. When not distributing air, in order to avoid high temperature to lead to the air feed pipe body to be heated and produce deformation, be provided with the pearlite layer of laying the constitution by the pearlite on the outer wall of body, the pearlite layer has apparent density light, thermal conductivity coefficient is low, chemical stability is good, service temperature range characteristics such as wide, lays and can reduce the body to be heated in the surface of body can showing, avoids the body to be heated deformation or damage. In addition, ceramic fiber cloth is wrapped outside the perlite layer, and the advantages of high temperature resistance, low heat conductivity coefficient, thermal shock resistance and low heat capacity of the ceramic fiber cloth are utilized, so that the heating capacity of the air supply pipe can be improved, the perlite layer can be stabilized, and the overall stability of the air supply pipe structure is improved. Preferably, the total thickness of the ceramic fiber cloth and the perlite layer is higher than the outlet end of the air outlet, or higher than a connecting seat arranged on the air outlet and used for connecting the ceramic nozzle. Through the setting, the perlite layer laid on the air supply pipe and the ceramic fiber cloth wrapped on the outermost layer can greatly improve the temperature resistance of the air supply pipe, so that the deformation of the air supply pipe at high temperature of the hearth can not occur when the air is not distributed, the service life of equipment is prolonged, and the accuracy of air distribution is enhanced.

In some embodiments, the detachable mode of the nozzle detachably connected to the air supply pipe and the air outlet of the pipe body may be a clamping connection or a threaded connection. Preferably, the outer wall of the nozzle is provided with external threads/internal threads, the air outlet is provided with a connecting seat, and the connecting seat is provided with matched internal threads/external threads so as to realize threaded connection between the nozzle and the air outlet. Through detachably connecting the nozzle, can change the nozzle according to actual wind field before the air distribution to adjust the orientation of nozzle, air-out angle, air-out form, air output isoparametric, the parameter of the nozzle on the same air distribution pipe can be the same also can be different.

As a preferred structure of the nozzle in the invention, the air outlets of the first air supply pipe and the second air supply pipe are detachably connected with the nozzle, the nozzle comprises a nozzle main body, spiral grooves spirally extending along the inner wall of the nozzle main body are arranged in the nozzle main body, a partition plate is arranged in the nozzle main body, the partition plate divides the inner space of the nozzle main body into an air inlet area communicated with the air inlet end and a cyclone area communicated with the air outlet end, a beveled hole communicated with the air inlet area and the cyclone area is arranged on the partition plate, an included angle is formed between the central axis of the beveled hole and the central axis of the partition plate, at least one vortex tube is further arranged on the nozzle main body, a vortex-assisting air passage is formed inside the vortex-assisting tube, one end of the vortex-assisting air passage is communicated with the air inlet area, and the other end of the vortex-assisting air passage is communicated with the cyclone area.

In this technical scheme, the main part of nozzle preferably adopts straight tube or L shape return bend structure. The straight pipe structure can better form spiral wind, the manufacturing process is simpler, and the mass production is easy; the L-shaped elbow structure can adjust the orientation of the air outlet end of the nozzle, and then allows the angle to be adjusted according to the actual demand of a wind field so as to realize better air supply or air distribution, the spiral groove is a groove arranged on the inner wall of the main body, the extending direction of the groove is the extending direction of the spiral line of the inner wall of the main body, and the flowing mode of the air flow is changed by arranging the spiral groove on the inner wall of the main body. The air flow rotates gradually in the process of moving from the air inlet end to the air outlet end in the main body, and is finally sprayed out from the air outlet end in a spiral air flow state, so that the forms of air supply and air distribution of a hearth in the prior art are changed, a better impact stirring effect is played on an air field in the hearth, the air field is more uniform, the contact and reaction time of oxygen and coal, carbon dioxide and coal, carbon monoxide and oxygen and other gases is prolonged, the utilization rate of carbon dioxide and coal is improved, and the emission of smoke dust, carbon dioxide and other emissions is effectively reduced.

In the technical scheme, the partition plate divides the inner space of the main body into an air inlet area communicated with the air inlet end and a cyclone area communicated with the air outlet end, and air flow enters the cyclone area from the air inlet area through a plurality of inclined cutting holes formed in the partition plate. The axis in chamfer hole, the generating line also has the contained angle with the axis of baffle for when the air current was through the chamfer hole, receive the guide in chamfer hole and the redirecting produces spiral air current. Although the setting of baffle has produced the resistance to gas flow to a certain extent, can be faster, high-efficiently with the faster air current conversion spiral air current of central velocity of flow, the cooperation mainly changes the helicla flute of marginal air current flow mode, can form the helicla flute in the main part more fast, has improved the conversion efficiency of air current motion form more significantly, forms the spiral air current of stable injection at the gas outlet end of main part. Preferably, the helical groove is provided in the cyclonic zone.

In the technical scheme, a cyclone-assisting air passage is formed in the cyclone-assisting pipe, and two ends of the cyclone-assisting air passage are respectively communicated with the air inlet area and the cyclone area, so that a small part of air in the air inlet area enters the cyclone-assisting pipe before contacting with the partition plate, and then returns to the main body through a connecting port of the cyclone-assisting air passage and the cyclone area. The returned vortex-assisted airflow has a bias effect because the incident direction is not consistent with the airflow flowing direction in the cyclone area, impacts the main airflow and causes the main airflow to rotate to a certain degree, further improves the conversion efficiency of the airflow motion form, and is beneficial to forming stable spiral airflow in the cyclone area more quickly.

The invention also provides a combustion method with low carbon dioxide emission, which adopts any one of the coal-fired boilers, and comprises the following steps:

the opposite angle air inlets of the combustion air supply area and the burnout air supply area input air and pulverized coal mixed airflow into the furnace body to form a tangential circular wind field;

the bottom ascending airflow enters the furnace body from a bottom air inlet, and vertically and upwards passes through tangential circular wind fields corresponding to the combustion air supply area and the burnout air supply area to move to an air outlet;

and the sinking airflow passes through the central airless area of the tangential wind field and sinks to the bottom of the boiler to be mixed with the bottom updraft.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the sinking air flow generated by the sinking air supply area forms a barrier above the burnout air supply area to block smoke dust and CO to a certain extent₂、SO₂、NO_XWhen the emissions go upwards, the sinking air flow sinks from the central airless area and is combined with the ascending air flow at the bottom to form a circulating air flow, the circulating air flow conveys the emissions above the burnout air supply area to the bottom of the boiler, and in the sinking process, the emissions are combusted with oxygen and coal for the second time, so that the contact time of the emissions, the coal and the oxygen is increased, the reaction of all the substances is more sufficient, the burnout rate of the fuel is obviously improved, the coal burning cost is reduced, solid particle impurities in smoke dust are reduced, and CO is reduced₂、SO₂、NO_XThe discharge amount of the gas emission reduces the treatment difficulty and the treatment load of the post-treatment process;

2. the second air supply pipe distributes air to the tangential circular air field to obviously reduce the area of a weak air area, so that the air field in the boiler is more uniform, the oxygen supply is more reasonable and sufficient, the coal is more fully combusted, the discharge amount of emissions of smoke dust, carbon dioxide and the like is reduced, the air flow fullness of the whole section is better, particularly the air supply system is close to the wall surface, the flow is enhanced by the air supply system, high-temperature gas is separated from the wall surface, the scouring of flame to the wall surface is reduced, and the ash hanging and slag bonding of the wall surface of the boiler are effectively prevented;

3. according to the invention, by arranging the upper, middle and lower three-stage air supply areas and utilizing the lower air supply area, the combination of the fuel surface area and oxygen is increased, the contact time is prolonged, the overflow amount of fuel combustible is increased, the ascending channel of waste particles with large self-weight is blocked to a certain extent, and the emission amount of the waste particles is reduced; the middle air supply area forms combustion-supporting force for the combustion flame, so that the combustion and the heat value of the flame are enhanced, the middle air supply area not only meets the oxygen supply requirement of the combustion flame, but also can promote the more uniform airflow impact of an air field to fully combust the particles again; the upper air supply area is used for preventing unburned coal from continuously rising to a certain degree or forming a return channel, so that the contact time of the coal and oxygen is further prolonged, and the coal in the boiler is fully combusted;

4. the perlite layer paved on the air supply pipe and the ceramic fiber cloth wrapped on the outermost layer can greatly improve the temperature resistance of the air distribution pipe, ensure that the air distribution pipe does not deform at high temperature of a hearth when air is not distributed, prolong the service life of equipment and enhance the accuracy of air distribution;

5. the nozzle of the invention enables the airflow to gradually rotate in the process of moving from the air inlet end to the air outlet end in the main body, and finally the airflow is ejected from the air outlet end in a spiral airflow state, thereby changing the forms of air supply and air distribution of the hearth in the prior art, playing a better impact stirring role on an air field in the hearth, not only enabling the air field to be more uniform, but also increasing the contact and reaction time of oxygen and coal, carbon dioxide and coal, carbon monoxide and oxygen and other gases, improving the utilization rate of carbon dioxide and coal, and effectively reducing the emission of smoke dust, carbon dioxide and other emissions;

6. according to the nozzle, the partition plate is arranged, so that the air flow with the higher central flow velocity can be converted into the spiral air flow more quickly and efficiently, the spiral groove which mainly changes the flowing mode of the edge air flow is matched, the spiral groove can be formed in the main body more quickly, the conversion efficiency of the air flow movement form is obviously improved, and the stably-sprayed spiral air flow is formed at the air outlet end of the main body;

7. the nozzle of the invention utilizes the bias of the auxiliary cyclone airflow with the incident direction different from the airflow flowing direction in the cyclone area to impact the main airflow to cause the main airflow to rotate to a certain degree, thereby further improving the conversion efficiency of the airflow motion form and being beneficial to forming stable spiral airflow in the cyclone area more quickly.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic view of a prior art boiler;

FIG. 2 is a schematic view of a prior art wind field of a cross section of a boiler furnace;

FIG. 3 is a schematic structural view of a boiler according to an embodiment of the present invention;

FIG. 4 is a schematic view of the air supply of the sinking air supply zone in an embodiment of the present invention;

FIG. 5 is a schematic view of the wind field of the upper/middle/lower wind supply area in an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a second air supply duct in an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a nozzle in an embodiment of the invention;

FIG. 8 is a schematic diagram of a baffle plate of a nozzle in an embodiment of the invention;

FIG. 9 is a schematic view of a chamfered hole in a baffle plate of a nozzle in an embodiment of the invention.

Reference numbers and corresponding part names in the drawings:

1-furnace body, 2-bottom air inlet, 3-air outlet, 4-slag outlet, 5-combustion air supply area, 6-burnout air supply area, 7-lower air supply area, 8-middle air supply area, 9-upper air supply area, 10-sinking air supply area, 11-sinking air flow, 12-bottom updraft, 13-spiral wind, 14-diagonal air inlet, 15-first air supply pipe, 16-second air supply pipe, 161-pipe body, 162-air inlet, 163-air outlet, 164-perlite layer, 165-ceramic fiber cloth, 17-central airless area, 18-nozzle, 181-nozzle body, 182-spiral groove, 183-necking section, cyclone tube, 185-partition plate, 1851-inner ring area, 1852-outer ring zone, 186-chamfered hole, 187-vertical section, 188-horizontal section, 19-sinking mixed gas stream;

201-furnace wall, 202-diagonal air inlet, 203-strong air area, 204-weak air area, 205-no air area, 206-burnout layer and 207-combustion layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

In the description of the present invention, it is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore, should not be taken as limiting the scope of the invention.

Example 1:

the coal-fired boiler with low carbon dioxide emission shown in fig. 3 to 5 comprises a boiler body 1, wherein a bottom air inlet 2, an air outlet 3, a combustion air supply area 5 and a burnout air supply area 6 are arranged on the boiler body 1, air is supplied into the boiler body 1 from diagonal air inlets 14 of the combustion air supply area 5 and the burnout air supply area 6 to form a tangential air field, the coal-fired boiler further comprises a sinking air supply area 10 positioned above the burnout air supply area 6, the sinking air supply area 10 is used for spraying sinking air flow 11 to the center of the boiler body 1, and the sinking air flow 11 passes through a central airless area 17 of the tangential air field and sinks to the bottom of the boiler to be mixed with ascending air flow 12 at the bottom of the boiler.

In some embodiments, as shown in fig. 4, the sinking air supply area 10 includes a first air supply pipe 15 installed on the inner wall of the furnace body 1, the first air supply pipe 15 includes a pipe body 161, a plurality of nozzles 18 are detachably arranged on the pipe body 161, and the nozzles 18 face the central airless area 17.

In one or more embodiments, the air outlet end of the nozzle 18 on the first air supply pipe 15 is inclined downwards by 5-15 degrees.

In one or more embodiments, the air supply amount of the sinking air supply area 10 is 10% -20% of the total air amount entering the furnace body 1.

In one or more embodiments, as shown in fig. 3, the bottom of the boiler is also provided with a slag discharge port 4 for discharging the heavier solid particulate impurities out of the furnace.

The sinking air flow generated by the sinking air supply area forms a barrier above the burnout air supply area to block smoke dust and CO to a certain extent₂、SO₂、NO_XWhen the emissions go upwards, the sinking air flow sinks from the central airless area and is combined with the ascending air flow at the bottom to form a circulating air flow, the circulating air flow conveys the emissions above the burnout air supply area to the bottom of the boiler, and in the sinking process, the emissions are combusted with oxygen and coal for the second time, so that the contact time of the emissions, the coal and the oxygen is increased, the reaction of all the substances is more sufficient, the burnout rate of the fuel is obviously improved, the coal burning cost is reduced, solid particle impurities in smoke dust are reduced, and CO is reduced₂、SO₂、NO_XThe treatment difficulty and the treatment load of the post-treatment process are reduced.

Example 2:

on the basis of embodiment 1, as shown in fig. 3, the furnace body 1 is further provided with a lower air supply area 7 and a middle air supply area 8, the lower air supply area 7 is located below the combustion air supply area 5, the middle air supply area 8 is located between the combustion air supply area 5 and the burnout air supply area 6, the lower air supply area 7 comprises two sets of air supply assemblies, the middle air supply area 8 comprises three sets of air supply assemblies, as shown in fig. 5, the air supply assemblies comprise diagonal air inlets 14, the diagonal air inlets 14 are used for supplying air into the furnace body 1 to form a tangential air field, a second air supply pipe 16 is arranged between two adjacent diagonal air inlets 14, and the second air supply pipe 16 is used for distributing air to the tangential air field; the air supply rate of the middle air supply zone 8 is 25-35% of the total air supply rate entering the furnace body 1, and the air supply rate of the lower air supply zone 7 is 5-10% of the total air supply rate entering the furnace body 1.

In some embodiments, as shown in fig. 3, an upper air supply area 9 is disposed between the burnout air supply area 6 and the sinking air supply area 10, the upper air supply area 9 includes at least one set of air supply components, and an air supply amount of the upper air supply area 9 is greater than an air supply amount of the lower air supply area 7 and smaller than an air supply amount of the middle air supply area 8.

In the embodiment, by arranging the upper, middle and lower three-stage air supply areas, the combination of the surface area of the fuel and oxygen is increased by utilizing the lower air supply area, the contact time is prolonged, the overflow amount of combustible materials of the fuel is increased, the ascending channel of waste particles with large self-weight is blocked to a certain extent, and the emission amount of the waste particles is reduced; the middle air supply area forms combustion-supporting force for the combustion flame, so that the combustion and the heat value of the flame are enhanced, the middle air supply area not only meets the oxygen supply requirement of the combustion flame, but also can promote the more uniform airflow impact of an air field to fully combust the particles again; the upper air supply area is used for preventing unburned coal from continuously rising to a certain degree or forming a return channel, so that the contact time of the coal and oxygen is further prolonged, and the coal in the boiler is fully combusted.

In some embodiments, as shown in fig. 6, the second air supply pipe 16 includes a pipe body 161, the pipe body 161 is provided with an air inlet 162 and a plurality of air outlets 163 distributed along an axial direction of the pipe body 161, the air inlet 162 is located at an end of the second air supply pipe 16, and the air inlets 162 of two adjacent second air supply pipes 16 are close to different diagonal air inlets 14. The second air supply pipe distributes air to the tangential wind field to obviously reduce the area of the weak wind area, so that the wind field in the furnace is more uniform, the oxygen supply is more reasonable and sufficient, the coal combustion is more sufficient, the emission of emissions of smoke dust, carbon dioxide and the like is reduced, the air flow fullness of the whole cross section is better, particularly, the air supply system is close to the wall surface, the air supply system enables the flow to be enhanced, high-temperature gas and the wall surface are isolated, the flame scouring to the wall surface is reduced, and the wall surface of the boiler is effectively prevented from being coated with ash and slagging.

In one or more embodiments, the distance between two adjacent air outlets gradually increases along the direction from the end of the tube body of the second air supply pipe, where the air inlet is arranged, to the other end of the tube body. In this technical scheme, the air outlet that is close to the body air intake is more, and the air outlet of keeping away from the body air intake still less, should set up and make the air distribution pipe from being provided with air intake one end to the other end, and the wind speed of air-out, amount of wind further reduce gradually to make the air distribution pipe can strengthen the weak wind district in wind field better, further improve wind field homogeneity.

In one or more embodiments, the diameter of the outlet end of the air outlet or the nozzle is gradually reduced along the direction from the end provided with the tube body to the other end of the tube body. The diameter reduces can further reduce the air output, through the mode that air outlet or nozzle diameter reduce gradually among this technical scheme for along the air output from the tip that is provided with the body to the direction of the body other end further reduces.

In one or more embodiments, a perlite layer 164 is laid on the tube body 161 of the first air supply duct 15 or the second air supply duct 16, and the outer surface of the perlite layer 164 is covered with a ceramic fiber cloth 165. In this embodiment, the perlite layer of laying on the air feed pipe to and the temperature resistance that the parcel can greatly promote the air feed pipe at outmost ceramic fiber cloth, guarantee that the air feed pipe can not appear warping under the furnace high temperature when not distributing wind, prolonged the life of equipment, and strengthened the accuracy of air distribution.

Example 3:

as shown in fig. 7 to 9, in the above embodiments, the air outlets 163 of the first air supply duct 15 and the second air supply duct 16 are detachably connected with the nozzles 18, the nozzle 18 comprises a nozzle main body 181, a spiral groove 182 extending spirally along the inner wall of the nozzle main body 181 is arranged in the nozzle main body 181, a baffle 185 is arranged in the nozzle main body 181, the partition 185 divides the inner space of the nozzle body 181 into an air inlet region communicating with the air inlet end and a cyclone region communicating with the air outlet end, the baffle 185 is provided with a bevel cut hole 186 for communicating the air inlet area and the cyclone area, the central axis of the bevel cut hole 186 forms an included angle with the central axis of the baffle 185, the nozzle main body 181 is also provided with at least one coil-assisted pipe 184, the inside of the vortex-assisting pipe 184 forms a vortex-assisting air passage, one end of the vortex-assisting air passage is communicated with the air inlet area, and the other end of the vortex-assisting air passage is communicated with the cyclone area.

In the embodiment, the nozzle enables the airflow to gradually rotate in the process of moving from the air inlet end to the air outlet end in the main body, and finally the airflow is ejected from the air outlet end in a spiral airflow state, so that the forms of air supply and air distribution of the hearth in the prior art are changed, a better impact stirring effect is achieved on an air field in the hearth, the air field is more uniform, the contact and reaction time of oxygen and coal, carbon dioxide and coal, carbon monoxide and oxygen and other gases is prolonged, the utilization rate of carbon dioxide and coal is improved, and the emission of smoke dust, carbon dioxide and other emissions is effectively reduced. Simultaneously, the baffle can be faster, high-efficient ground with the faster air current of central velocity of flow conversion spiral air current more, cooperates the helicla flute that mainly changes marginal air current flow mode, can form the helicla flute in the main part more fast, has showing the conversion efficiency who has improved the air current motion form, forms the spiral air current of stable injection at the gas outlet end of main part. In addition, the nozzle utilizes the bias of the auxiliary cyclone airflow with the incident direction different from the airflow flowing direction in the cyclone area to impact the main airflow to cause the main airflow to rotate to a certain degree, thereby further improving the conversion efficiency of the airflow motion form and being beneficial to forming stable spiral airflow in the cyclone area more quickly.

In one or more embodiments, as shown in fig. 8, the partition 185 is provided with an inner ring area 1851 and an outer ring area 1852 located outside the inner ring area, the chamfered holes 186 are provided in the inner ring area and the outer ring area, and the number of the chamfered holes in the inner ring area is greater than that in the outer ring area. The baffle plate is provided with an inner circular ring area and an outer circular ring area, and the inclined cutting holes are only arranged on the two circular ring areas. The oblique holes in the inner ring area are mainly used for changing the air flow movement state at the center of the air flow and nearby, and the oblique holes in the outer ring area are mainly used for changing the air flow state close to the inner wall of the main body. Because the air current velocity of flow of center department is faster than the edge, and the air current of edge receives the influence of helicla flute bigger, consequently, sets up the quantity of the chamfer hole that the district was gone up to the inner ring to be more than the chamfer hole quantity of outer ring district to make the air current whole can more evenly, smoothly switch over to the spiral flow state, reduce the local vortex or the jam that appear in the runner, further improve the air current stability of conversion efficiency and exit end. In one embodiment, the number of the oblique cutting holes on the inner ring area is 2-5 times of the number of the oblique cutting holes on the outer ring area. The ratio of the number of the oblique cutting holes on the inner ring area and the outer ring area can be adjusted adaptively according to the inner diameter of the main body, preferably, the number of the oblique cutting holes on the inner ring area is 2-4 times of the number of the outer ring area, and more preferably, the ratio is 2-3 times. In one embodiment, an included angle between a central axis of the oblique cutting hole and a central axis of the partition plate is 30-70 degrees. Preferably, the included angle is 45-60 degrees.

In one or more embodiments, the connection port of the cyclone-assisted air passage and the cyclone area is distributed along a spiral line of the outer wall of the main body. The helix of outer wall is similar with the helix that the inner wall helicla flute extends, and equidistant or the distribution that varies on the helix has at least one connector for the multistrand that enters into each helping the whirlwind gas channel in the air intake district helps whirlwind air current can be in the different cross sections in the whirlwind district surely to impact main part air current, and then accelerates the formation of the spiral air current in the whirlwind district and stabilize.

Example 4:

on the basis of the above embodiment, as shown in fig. 3, a low carbon dioxide emission combustion method using the coal-fired boiler of any one of the preceding claims, the method comprises the steps of:

the mixed air flow of air and coal powder is input into the furnace body 1 from the diagonal air inlets 14 of the combustion air supply area 5 and the burnout air supply area 6 to form a tangential circular air field;

the bottom ascending air flow 12 enters the furnace body 1 from the bottom air inlet 2, and the bottom ascending air flow 12 vertically and upwards passes through tangential circular air fields corresponding to the combustion air supply area 5 and the burnout air supply area 6 and moves towards the air outlet 3;

the sinking air flow 11 passes through the central calm zone 17 of the tangential wind field and sinks to the bottom of the boiler to be mixed with the ascending air flow at the bottom.

As used herein, "first," "second," etc. merely distinguish the corresponding components for clarity of description and are not intended to limit any order or to emphasize importance, etc. Further, the term "connected" used herein may be either directly connected or indirectly connected via other components without being particularly described.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.