CN1092076C - Decoupled recirculating fluidized bed combustion system and its desulfurizing and denitrating process - Google Patents
Decoupled recirculating fluidized bed combustion system and its desulfurizing and denitrating process Download PDFInfo
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Abstract
The present invention relates to a solid fuel burning system of a fluidized bed. The present invention splits the burning of coal in a fluidized bed to two steps of air dry distillation and semi coke burning for solving the contradiction between desulphurization and denitration. Raw coal is supplied to a dry distillation zone; desulfurizing agents are added in a semi coke burning zone; high-temperature ash containing a certain quantity of desulfurizing agents, which is returned by a separator, is used for heating the raw coal. Sulphurous gas released by a dry distillation process of the raw coal is caught by the desulfurizing agents; semi coke generated by dry distillation enters a desulphurization zone of the lower part of a burning zone; NOx generated by the burning of the semi coke reacts with reducing gas generated by dry distillation in the burning zone for denitration. The system has the advantages of simple devices, effective desulphurization and denitration, low cost and easy popularization.
Description
The invention relates to fluidized bed solid fuel combustion and equipment technology, in particular to a method for oxidation desulfurization and reduction denitration in a circulating fluidized bed combustion system (CFBC).
The circulating fluidized bed combustion is considered as the best mode for realizing clean coal combustion, is widely applied to the combustion of coal, biomass and waste, and has advantages in desulfurization, denitrification and combustion efficiency due to the low-temperature combustion of the circulating bed and good heat and mass transfer and mixing performance, thereby being widely valued by countries in the world and having wide development prospect, however, the existing circulating fluidized bed combustion has the following problems:
1. desulfurization and denitration are simultaneously carried out, however, the influence of many conditions on the two processes is opposite, so that the two processes cannot be respectively optimized, only the two processes can be properly considered, and the desulfurization effect and the denitration effect are seriously influenced.
2. Coal and desulfurizer are both supplied to the region with the highest oxygen concentration and temperature in the bed, and the temperature is rapidly raised, and dry distillation and combustion are simultaneously carried out, thereby inhibiting the generation of reducing substances beneficial to denitration, and increasing the emission of nitrogen oxides.
3. Although low temperature combustion reduces NO and SO2But increased N2And (4) discharging O.
For simultaneous NOx and SO reduction2The discharge of (2) has been done by many scholars, for example, in a staged combustion mode, i.e. oxygen is not fed into the bed at one time, but rather, a secondary air inlet is provided at a position higher than the bed, and even a tertiary air inlet is providedSuch that an anoxic condition may be created in the lower portion of the circulating bed, which is beneficial in reducing NOx emissions [ ① Khan, W.U.Z.and Gibbs, S.M. (1991) Proc. of the 11th int. Conf. onFBC, Montreal, p.1503; ② Volk, M.et al. (1989), Proc. ofhe 10th int. Conf. on FBC, San Francisco, p.995; ③ Nack, H.et al. (1980), Proc. of the 6th int. Conf. on FBC, Atlanta, p.979]Another aspect is the so-called internal circulating fluidized bed, which reduces NOx emissions by making one region oxygen-poor and another region oxygen-rich by internals and air supply means ④ Hirota,T.et al.(1990)，Proc.of the 3rd Int.Conf.on CFB，Nagoya，p.491]lin et al, most significantly, propose that coal be gasified in another fluidized bed before beingcombusted in the fluidized bed, that the char produced by gasification be combusted in the fluidized bed, and that the gaseous material produced by gasification be fed to the combustion fluidized bed to promote the denitration process and burn off, for the circulating bed, they propose that coal, desulfurizing agent and high-temperature ash be mixed and gasified in another fluidized bed [ ⑤ Lin, Weigang (1994), Ph.D. thesis, Delft University of Technology, p.195]. And still uses a graded air supply mode in the circulating bed. However, these ideas still do not solve the contradiction between desulfurization and denitrification (simultaneous addition of the desulfurizing agent and coal) and the problem of thorough separation of carbonization and combustion (air existing during heating of coal), and are difficult to implement. For example, staged combustion can only reduce NOx emissions, but desulfurization and denitrification are not optimized because coal cannot be dry distilled in the absence of air and sufficient oxygen is not available during desulfurization. The concept of Lin et al, although promoting the formation of reducing gases, is advantageous for denitration, does not allow for dry distillation of coal in the absence of air due to the oxygen supply during gasification, and the simultaneous and concurrent addition of desulfurizing agent and coal does not result in optimal configuration of the desulfurizing agent, fuel and air for desulfurization and denitration. For N2As the control of O, it has been proposed to use gas after-furnace combustion (gas after burning) and N2Solid-catalyzed decomposition of O [ ⑥ Jan Remmert Pels (1995), Ph.D. thesis, Delftuniversity of Technology, p.270]E.g. to eliminate N2O, has patent newspaperPlacing a zeolite catalyst between two electrodes for generating plasma, N2O can be effectively decomposed into N2And O2(ii) a Decomposition of N by irradiation with ArF laser beam2O, reduced by 90% (from 50 to 5 ppm); n conversion using UV lamp in combination with photochemical catalysis2Decomposition of O to N2And O2It is also contemplated to use radiation-induced decomposition (radiation-induced techniques) to remove NOx/N from the exhaust2O/SOx, however, these techniques are too costly to develop and apply.
Li et al, for solving the problems of NOx and smoke emission in small coal-fired equipment, invented a technology which makes coal gradually raise temperature and dry distill under the condition of isolating air, then supply oxygen to burn at the bottom, and the volatile component containing reducing substance in the dry distill product reacts with NOx produced by semicoke burning so as to attain the goal of inhibiting NOx [ ⑦ Lijing sea, etc., Chinese patent application No. 95102081.1].
The invention aims to provide a decoupling circulating fluidized bed coal combustion device and a method for simultaneously desulfurizing and denitrifying the same. Coal is added into the dry distillation chamber, and a desulfurizer is added into the semicoke combustion chamber, so that coal isolated air is gradually heated and dry distilled under the condition of low desulfurizer concentration to generate reducing substances as much as possible, and the reducing substances are introduced into the upper part of the combustion zone for denitration, thereby ensuring that sufficient oxygen and high desulfurizer concentration exist in the semicoke combustion zone, and achieving the purposes of solving the contradiction between desulfurization and respectively optimizing the two processes.
The invention provides a decoupling circulating fluidized bed coal for oxidative desulfurization and reductive denitration
Combustion system "(CFBC).
The invention also provides a new concept and a specific process method of oxidative desulfurization and reductive denitration of the decoupling circulating fluidized bed coal combustion system.
The invention discloses a decoupling circulating fluidized bed coal combustion system and a desulfurization and denitrification process method thereof, which mainly comprise the following steps:
1. decoupling the process: by decoupling the dry distillation and semicoke combustion of the coal, a part of nitrogen elements in the coal are promoted to be separated out by reducing gases, and the reducing gases react with nitrogen oxides formed by semicoke combustion to achieve the aim of denitration.
2. Feeding materials at different positions: the coal bee desulfurizer is respectively added into the dry distillation chamber and the combustion chamber, so that the optimal operation of desulfurization in an oxidizing atmosphere and at a high desulfurizer concentration and denitration in a reducing atmosphere and at a low desulfurizer concentration is realized. In addition, the coal is added into the dry distillation chamber, the temperature rising speed is slow, dry distillation products are combusted in the middle of the combustion chamber, the temperature is raised, and the reduction of N is facilitated2And (4) discharging O.
3. And (3) carrying out partition desulfurization and denitration: by means of the decoupling of the feeding and the process, the desulfurizing and denitrating are performed in different places, so that the two contradictory processes can be respectively adjusted to respective favorable conditions, and the optimal fuel, desulfurizing agent, temperature level and air configuration are realized.
The basic concept of the invention is as follows: the coal contains various elements such as C, H, N, S and ash, and can generatea part of gaseous substances mainly comprising NH in the coal heating process3，H2，CH4，HCN，H2S, NOx and the like, and if oxygen exists during heating, the amount of the precipitated reducing gas decreases. S and N in the coal are separated out in volatile matters, and part of S and N in the coal forms SO in the semicoke combustion process2And NOx. Desulfurization mainly depends on the addition of a desulfurizing agent (such as CaO), sufficient air excess coefficient, good desulfurizing agent activity and high desulfurizing agent concentration, and the reduction of SO formed in the combustion process2Is advantageous. But the influence of the temperature on the desulfurization shows an optimal value (generally, the desulfurization effect is better at 800-900 ℃, and the optimal value is 850 ℃). Denitration can be realized through reaction with reducing substances, but at present, NOx emission is controlled mostly by adjusting combustion conditions, generally, the lower the oxygen concentration is, the more favorable the reducing gases are generated, the NOx formation is controlled, the lower the combustion temperature is, the less NOx emission is, and desulfurization isPresence of agent on NOx, and therefore desulfurization and denitrification are contradictory. The invention separately carries out the two processes of desulfurization and denitration, and respectively realizes the optimization control of the two processes.
In addition, oxygen is not needed in the coal heating process, and if the coal temperature rise carbonization and combustion are simultaneously carried out, the oxygen exists and is rapidly increased at high temperature, so that the effect of only inhibiting the generation of reducing substances to increase NOx and N is achieved2Side effects of O emissions. Therefore, the invention separately carries out dry distillation and combustion, realizes the optimal oxygen supply, promotes the generation of reducing substances, and reduces NOx and N2And (4) discharging O.
The invention discloses a decoupling circulating fluidized bed coal combustion system, which is characterized in that:
(1) the system consists of a combustion chamber, a dry distillation chamber and a gas/solid separation device, wherein the upper part of the combustion chamber is a dilute phase section denitration region, the lower part of the combustion chamber is a dense phase section desulfurization region, dry distillation gas generated by the dry distillation chamber is introduced into the upper part of the combustion chamber, and generated semicoke enters the lower part of the combustion chamber;
(2) respectively supplying coal into the dry distillation chamber and supplying a desulfurizer CaO into the bottom of the combustion chamber to decouple dry distillation and semicoke combustion of the coal and to generate a reducing gas NH formed in the dry distillation process of the coal3Is reduced to N by reaction with nitrogen oxides NOx formed by burning semicoke2And SO formed by denitration and burning semicoke in oxidizing atmosphere2Reacts with high-concentration desulfurizer CaO at a proper temperature to form CaSO4And then desulfurization is carried out;
(3) the fresh coal fed into the dry distillation chamber and the high-temperature ash from the gas/solid separation device are mixed and heated under the anaerobic condition, the heating speed is slow, and the N reduction is facilitated2The temperature of the high-temperature ash is generally kept between 850 ℃ and 900 ℃, and the flow rate of the high-temperature ash is generally 10-15 times of that of fresh coal, so as to ensure that the temperature of the coal reaches about 800 ℃, and most of volatile matters and NH contained in the volatile matters3Separating out HCN;
(4) h produced in the retort chamber2And reacting the S with a desulfurizer CaO in the high-temperature ash to generate CaS.
The decoupling circulating fluidized bed coal combustion system is further technically characterized in that: the top of the dry distillation chamber is provided with a fresh coal feed port, the bottom of the combustion chamber is provided with an air supply port and an air distribution plate for supplying air, a desulfurizing agent supply port and an ash discharge port are arranged in a desulfurizing area at the lower part of the combustion chamber, the desulfurizing area and a denitrifying area of the combustion chamber are both provided with heat exchangers with different forms with certain areas, an exhaust port is arranged above the gas/solid separation device, a water vapor or circulating flue gas inlet port is arranged below the gas/solid separation device, a dipleg into which the high-temperature ash of the separated substance falls is arranged at the lower part of the dipleg, a material seal is arranged below the dipleg to drive the high-temperature ash to enter the dry distillation chamber, and.
The decoupling circulating fluidized bed coal combustion system is further characterized in that the structural connection, the function and the operation method of each part are as follows: the high-temperature ash carried by the flue gas in the circulating bed falls into a dipleg after being separated by a gas/solid separation device, and enters into the circulation through material sealing under the action of the water vapor or the circulating flue gas supplied from the bottomThe top of the circulating fluidized bed dry distillation chamber meets with the fresh coal fed therein and descends under the action of gravity, and the mixture is mixed and gradually heated for dry distillation; the dry distillation chamberpromotes the mixing of fresh coal and high-temperature ash by means of baffles and increases the retention time to facilitate the high-temperature dry distillation of the coal, and the slow heating speed is favorable for inhibiting N2Formation of O, H produced by dry distillation2S is absorbed by CaO, and the semicoke and the ash fall into a dense-phase combustion area at the bottom of the circulating bed combustor to meet and combust with air supplied through the distribution plate, and are desulfurized under the action of a supplied desulfurizer; combustible gas generated by the dry distillation chamber and a large amount of reducing substances NH contained in the combustible gas3Introducing into dilute phase zone at the top of the circulating bed from the middle part of the circulating bed, and burning the combustible with the residual oxygen to obtain NH3Reacts with NOx formed by combustion of the lower semicoke to form N2And then denitration is carried out; the combustion of the volatiles raises the temperature, favouring N2The decomposition of O and the temperature of the denitration area are adjusted by a heat exchanger.
The decoupled circulating fluidized bed coal combustion system of the present invention is further characterized in that the preferred embodiment (see fig. 3) comprises the following parts and components: a cyclone dust collector 1, a dipleg 2, a water vapor circulation flue gas inlet 3, a material seal 4, a dry distillation chamber 5, a fresh coal feeding hopper 6, a baffle 7, a channel 8, an air distribution plate 9,The device comprises an ash discharge port 10, a dense phase combustion zone 11 at the lower part of a combustion chamber, a desulfurizing agent supply port 12, a dilute phase combustion zone 13 at the upper part of the combustion chamber and a heat exchanger 14, wherein the connection relationship and the functions of the two are as follows: high-temperature ash carried by flue gas in a circulating bed is separated by a cyclone dust collector 1 and then falls into a dipleg 2, the high-temperature ash enters a dry distillation chamber 5 through a seal 4 under the action of water vapor, a baffle 7 arranged in the dry distillation chamber can prolong the retention time and mix of fresh coal and the high-temperature ash, semicoke and the high-temperature ash generated by the dry distillation chamber 5 fall into a dense phase combustion area 11 at the bottom of a combustion chamber of the circulating bed, the semicoke and the high-temperature ash meet and combust with air supplied by an air distribution plate 9 and are desulfurized under the action of a desulfurizer, and combustible gas and reducing substances NH generated by the dry distillation chamber 53Enters a dilute phase combustion zone 13 at the upper part of the circulating bed combustion chamber through a channel 8, and then combusts and reacts to denitrate, and a heat exchanger 14 is used for adjusting the temperature of the denitrating zone so as to optimize the conditions of desulfurization and denitration.
The decoupled circulating fluidized bed coal combustion system of the present invention is further characterized by another preferred embodiment (as shown in fig. 4) wherein no baffles are provided due to the bubbling bed configuration within the coal retort, a lower passageway 16 connecting the retort to the combustion chamber is added and another air inlet 15 is added.
The present invention will be further described with reference to the accompanying drawings.
FIG. 1 is a functional concept schematic diagram of a decoupling circulating fluidized bed coal combustion system and each structural part of the decoupling circulating fluidized bed coal combustion system. The figure illustrates that the CFBC of the present invention iscomprised of a combustion chamber, a retort chamber and a gas/solid separation unit. The method decouples the dry distillation and combustion separation, and can optimally control the desulfurization and the denitrification.
FIG. 2 is a schematic representation of the desulfurization and denitrification mechanism and the basic process of the present invention. The figure indicates the main chemical reactions that may occur in the retort chamber and the combustion chamber of the present invention, i.e. the H produced in the retort chamber2S andCaO in the high-temperature ash reacts to form CaS to be removed, and SO generated in a desulfurization zone of the combustor is removed2With the fed desulfurizer CaO to form CaSO under an oxidizing atmosphere4Is removed; reducing gas NH from the retort3And desulfurization from combustion chambersZone generated NOx and N2O reacts in the upper denitration zone of the combustion chamber to denitrate and discharge N2Smoke and small amount of NOx and N2And SO2。
FIG. 3 is a preferred embodiment of the decoupled circulating fluidized bed coal combustion system and its oxidative desulfurization and reductive denitrification process.
FIG. 4 is another preferred embodiment of the decoupled circulating fluidized bed coal combustion system of the present invention and its specific process for oxidative desulfurization and reductive denitrification.
According to the above inventive concept, the present invention provides a CFBC and a structural feature, desulfurization and denitrification process, as shown in fig. 1, the whole CFBC system is composed of a combustion chamber, a dry distillation chamber and a gas-solid separation device. The upper part of the combustion chamberis a denitration area, the lower part of the combustion chamber is a desulfurization area, and the boundary of the two areas can be adjusted according to the coal type, the operation condition and the like. Fresh coal is fed into the dry distillation chamber and mixed with high-temperature ash returned from the gas-solid separation device in the absence of oxygen to raise the temperature, the temperature of the high-temperature ash is generally kept between 850 ℃ and 900 ℃, the flow rate of the high-temperature ash is generally 10-15 times that of the fresh coal, so that the coal temperature reaches 800 ℃ to ensure that most volatile matters can be separated out, and the temperature raising speed of the coal is slow, so that the N can be favorably inhibited2And (4) generating O. The semicoke produced by dry distillation enters a combustion chamber to meet and combust with air fed from the bottom of the combustion chamber. The desulfurizer is fed into the bottom of the combustion chamber to ensure that the concentration of the desulfurizer in the desulfurization zone is highest, and the optimal desulfurization conditions are met because the concentration of the desulfurizer at the bottom of the combustion chamber is highest, the activity is best, and the oxygen concentration is also highest. NOx generated by semicoke combustion in the denitration zone at the upper part of the combustion chamber reacts with the reducing gas from the dry distillation chamber and is reduced into N2( ) Here, the oxygen concentration is very low and H contained in the combustible volatile matter2CO and the like are also beneficial to the reaction, and the combustible volatile meets with the residual oxygen to burn, so that the temperature of the area is increased, and N is beneficial to the reaction2The decrease of O. H produced in the retort chamber2S reacts with a desulfurizer CaO in the high-temperature ashto generate CaS, and the flue gas clampThe high-temperature ash enters a gas-solid separation device to realize gas-solid separation. Because the effective desulfurization of the lower part of the dry distillation chamber and the combustion chamber and the denitration of the reducing gas generated by the dry distillation in the upper part of the combustion chamber, NOx and N in the exhaust flue gas2O and SO2The content of (A) is very low.
Experiments prove that the structure can separate dry distillation and combustion, the reductive substance generated in the coal dry distillation process is utilized to the maximum extent for denitration, dense-phase section desulfurization and dilute-phase section denitration are carried out in the combustion chamber, and the two processes are not influenced by each other. The excess air coefficient of the desulfurization area reaches the maximum, the temperature is not limited by denitration, and the optimum temperature of desulfurization can be adjusted. The excess air coefficient of the denitration area can be very low, the concentration of reducing substances is very high, the concentration of a desulfurizer is reduced, and the temperature can be adjusted according to the denitration requirement. The invention solves the problem of the falling of the circulating bedThe contradictory problems of nitre and desulfurization can be summarized as follows:
examples
FIG. 3 is a preferred embodiment of the decoupled circulating fluidized bed combustion system of the present invention for further describing the present invention, and it can be seen from the figure that the high temperature ash carried by the flue gas in the circulating bed falls into the dipleg (2) after being separated by the cyclone (1), under the action of the loosening gas (3) (water vapor or recirculated flue gas), enters the top of the circulating fluidized bed dry distillation chamber (5) through the seal (4) to meet with the fresh coal fed from the particle hopper (6) and descend under the action of gravity and mix and gradually increase the temperature for dry distillation, the baffle (7) is arranged in the dry distillation chamber (5) to promote the mixing of the fresh coal and the high temperature ash and increase the retention time, so as to ensure that the coal can be heated and dry distilled, and the heating speed is slow, so it is beneficial to inhibit N from the present invention2And (4) generating O. H produced by dry distillation2S is absorbed by CaO in high-temperature ash to generate CaS, semicoke and ash generated by dry distillation fall into a dense-phase combustion zone (11) at the bottom of a circulating bed combustion chamber to meet and combust with air supplied by an air distribution plate (9), and desulfurization is carried out under the action of a supplied desulfurizer (12), and the Ca/S in the zone is high, and the oxygen concentration is high, so that the desulfurization process is facilitated. The dry distillation chamber (5) is isolated from air, so that the generated combustible gas contains a large amount of reducing substances NH3The gases are introduced into the dilute phase combustion zone (13) at the upper part of the circulating bed combustion chamber through a position-adjustable channel (8), the combustible material and the residual oxygen meet for combustion, NH3The reaction with NOx formed by the combustion of the lower semicoke achieves the purpose of denitration, since here it is located downstream of the desulfurization zone and the combustion of the semicoke, the Ca/S and oxygen concentrations are low, which is advantageous for the denitration process, and since the combustion of the volatiles, the temperature in this zone increases, which is advantageous for controlling N2And O is discharged, so that the optimal conditions of oxidative desulfurization and reductive denitration are realized, the temperature of the denitration area can be adjusted to a proper temperature through the heat exchanger (14), and the combustion waste gas carries high-temperature ash to enter the cyclone dust collector (1) for separation. Part of ashAnd CaSO4Is discharged from a bottom ash discharge port (10). SO in the flue gas discharged from the cyclone dust collector2And NOx and N2The concentration of O is very low, and the optimization of denitration and desulfurization is realized.
Fig. 4 is another embodiment. High-temperature ash carried by flue gas in the circulating bed falls into a dipleg (2) after being separated by a cyclone dust collector (1), falls into a dry distillation fluidized bed or a dry distillation chamber (5) through a material seal (4) and with fresh coal added by a feeding hopper (6) under the action of loose gas (3), the fresh coal is heated and dry distilled by the high-temperature ash under the fluidization of a small amount of circulating flue gas, and H generated by dry distillation2S is absorbed by CaO, and the semicoke enters the combustion chamber (11) to meet and combust with air supplied by the air distribution plate (9), and is desulfurized under the action of a desulfurizing agent supplied by a desulfurizing agent supply inlet (12), and the desulfurizing process is facilitated because the area has high Ca/S and high oxygen concentration. The dry distillation chamber (5) is isolated from air, so that the generated combustible gas contains a large amount of reducing substances NH3These gases are introduced into a dilute phase combustion zone (13) in the upper part of the circulating bed, where the combustibles are burnt against the residual oxygen, NH3The NOx formed by burning the semicoke at the lower part reacts to realize the denitration, and because the NOx is positioned at the downstream of the desulfurization area and the semicoke burning area, the concentration of Ca/S and oxygen is lower, which is beneficial to the denitration process, and the temperature is increased after the volatile matter is burnt, which is beneficial to the N2The decomposition of O, the temperature rising speed of the coal in the dry distillation chamber is slower, and the reduction of N is facilitated2And (4) discharging O. Thus realizing the optimum conditions of oxidative desulfurization and reductive denitration, denitrationThe temperature of the zone can be adjusted to a proper temperature through a heat exchanger (14), and the combustion waste gas carries high-temperature ash to enter a cyclone dust collector (1) for separation. Part of ash and CaSO4Is discharged from a bottom ash discharge port (10). SO in the flue gas discharged from the cyclone dust collector2And NOx and N2The concentration of O is very low, and the optimization of denitration and desulfurization is realized. Figure 4 differs from figure 3 only in that the retort section is not provided with baffles, in that a lower channel (16) connecting the retort chamber with the combustion chamber is added, and in that a further inlet (15) is added.
Claims (5)
1. A decoupling circulating fluidized bed coal combustion system is characterized in that:
(1) the system consists of a combustion chamber, a dry distillation chamber and a gas/solid separation device, wherein the upper part of the combustion chamber is a dilute phase section denitration region, the lower part of the combustion chamber is a dense phase section desulfurization region, dry distillation gas generated by the dry distillation chamber is introduced into the upper part of the combustion chamber, and generated semicoke enters the lower part of the combustion chamber;
(2) respectively supplying coal into the dry distillation chamber and supplying a desulfurizer CaO into the bottom of the combustion chamber to decouple dry distillation and semicoke combustion of the coal and to generate a reducing gas NH formed in the dry distillation process of the coal3Is reduced to N by reaction with nitrogen oxides NOx formed by burning semicoke2And SO formed by denitration and burning semicoke in oxidizing atmosphere2Reacts with high-concentration desulfurizer CaO at a proper temperature to form CaSO4And then desulfurization is carried out;
(3) the fresh coal fed into the dry distillation chamber and the high-temperature ash from the gas/solid separation device are mixed and heated under the anaerobic condition, the heating speed is slow, and the N reduction is facilitated2The temperature of the high-temperature ash is generally kept between 850 ℃ and 900 ℃, and the flow rate of the high-temperature ash is generally 10-15 times of that of fresh coal, so as to ensure that the temperature of the coal reaches about 800 ℃, and most of volatile matters and NH contained in the volatile matters3Separating out HCN;
(4) h produced in the retort chamber2And reacting the S with a desulfurizer CaO in the high-temperature ash to generate CaS.
2. The decoupled circulating fluidized bed coal combustion system of claim 1, wherein: the top of the dry distillation chamber is provided with a fresh coal feed port, the bottom of the combustion chamber is provided with an air supply port and an air distribution plate for supplying air, a desulfurizing agent supply port and an ash discharge port are arranged in a desulfurizing area at the lower part of the combustion chamber, the desulfurizing area and adenitrifying area of the combustion chamber are both provided with heat exchangers with different forms with certain areas, an exhaust port is arranged above the gas/solid separation device, a water vapor or circulating flue gas inlet port is arranged below the gas/solid separation device, a dipleg into which separated high-temperature ash falls is arranged below the dipleg, a material seal is arranged below the dipleg to drive the high-temperature ash to enter the dry distillation chamber, and the gas/solid separation device can.
3. The decoupled circulating fluidized bed coal combustion system of claim 1 or 2, characterized by structural connections, functions and methods of operation of the parts: the high-temperature ash carried by the flue gas in the circulating bed falls into a dipleg after being separated by a gas/solid separation device, enters the top of the dry distillation chamber of the circulating fluidized bed through a material seal under the action of the water vapor or the circulating flue gas supplied from the bottom, meets with the fresh coal supplied therein, descends under the action of gravity, and is mixed and gradually heated for dry distillation at the same time; the dry distillation zone promotes the mixing of fresh coal and high-temperature ash by means of baffles and increases the retention time to facilitate the high-temperature dry distillation of the coal, and the temperature rise speed is lower to facilitate the suppression of N2Formation of O, H produced by dry distillation2S is absorbed by CaO, while the char and ash fall into the cycleThe dense phase combustion zone at the bottom of the bed combustion chamber meets and burns with the air supplied through the distribution plate and desulfurizes under the action of the supplied desulfurizer; combustible gas generated by the dry distillation chamber and a large amount of reducing substances NH contained in the combustible gas3Introducing into dilute phase zone at the top of the circulating bed from the middle part of the circulating bed, and burning the combustible with the residual oxygen to obtain NH3Reacts with NOx formed by combustion of the lower semicoke to form N2And then denitration is carried out; the combustion of the volatiles raises the temperature, favouring N2The decomposition of O and the temperature of the denitration area are adjusted by a heat exchanger.
4. A decoupled circulating fluidized bed coal combustion system according to claim 1 or 2, characterized by comprising the following parts and components: a cyclone dust collector 1,The device comprises a dipleg 2, a steam or circulating flue gas inlet 3, a material seal 4, a dry distillation chamber 5, a fresh coal feeding hopper 6, a baffle 7, a channel 8, an air distribution plate 9, an ash discharge port 10, a lower dense phase combustion zone 11, a desulfurizer feeding inlet 12, an upper dilute phase combustion zone 13 and a heat exchanger 14, wherein the connection relationship and the function of the two are as follows: high-temperature ash carried by flue gas in a circulating bed is separated by a cyclone dust collector 1 and then falls into a dipleg 2, the high-temperature ash enters a dry distillation chamber 5 through a seal 4 under the action of water vapor, a baffle 7 arranged in the dry distillation chamber can prolong the retention time and mix of fresh coal and the high-temperature ash, semicoke and the high-temperature ash generated by the dry distillation chamber 5 fall into a dense phase combustion area 11 at the bottom of a combustion chamber, the semicoke and the high-temperature ash meet and combust with air supplied by an air distribution plate 9 and are desulfurized under the action of a desulfurizer, and combustible gas and reducing substance NH generated by the dry distillation chamber 53Enters a dilute phase combustion zone 13 at the upper part of the combustion chamber through a channel 8, and then combusts and reacts to denitrate, and a heat exchanger 14 is used for adjusting the temperature of the denitrating zone so as to optimize the conditions of desulfurization and denitration.
5. The decoupled circulating fluidized bed coal combustion system of claim 4, further characterized by the absence of baffles in the coal retort due to the bubbling bed configuration, the addition of a lower channel 16 connecting the retort to the combustion chamber and the addition of another air inlet 15.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN97112562A CN1092076C (en) | 1997-06-25 | 1997-06-25 | Decoupled recirculating fluidized bed combustion system and its desulfurizing and denitrating process |
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| CN97112562A CN1092076C (en) | 1997-06-25 | 1997-06-25 | Decoupled recirculating fluidized bed combustion system and its desulfurizing and denitrating process |
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| CN1092076C true CN1092076C (en) | 2002-10-09 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106215656A (en) * | 2016-09-09 | 2016-12-14 | 成都九十度工业产品设计有限公司 | A kind of ozone mixing reactor |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102563690B (en) * | 2012-02-08 | 2014-02-12 | 河南省电力公司电力科学研究院 | Method for controlling emission of nitrogen oxide of coal burning boiler |
| CN103884013B (en) * | 2014-03-26 | 2016-08-17 | 东方电气集团东方锅炉股份有限公司 | Manifold type environment-friendly type fluidized-bed combustion boiler combustion method and device |
| CN106178907A (en) * | 2015-04-29 | 2016-12-07 | 周建强 | A kind of CFBB ultra-fine desulfurizer granule sulfur method |
| CN105536468A (en) * | 2015-12-31 | 2016-05-04 | 神华集团有限责任公司 | Denitration method |
| CN112879912A (en) * | 2021-02-08 | 2021-06-01 | 中国科学院过程工程研究所 | Solid waste decoupling combustion device, combustion system device and combustion method thereof |
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| CN87104309A (en) * | 1986-05-20 | 1988-03-02 | 煤气技术研究所 | The method of removing sulphur compound when the carbonaceous solids particle gasifies in the fluidized-bed |
| JPS6418431A (en) * | 1987-07-14 | 1989-01-23 | Mitsui Shipbuilding Eng | Denitration method for circulating type fluidized layer boiler |
| CN1103658A (en) * | 1993-07-12 | 1995-06-14 | 凯洛格总公司 | Coal gasification and sulfur removal process |
| CN1110776A (en) * | 1995-03-07 | 1995-10-25 | 中国科学院化工冶金研究所 | No-smoke burning coal method for control nitrogen oxide and stove and application |
| JPH09159101A (en) * | 1995-12-01 | 1997-06-20 | Babcock Hitachi Kk | Pressurized fluidized bed boiler and operation method thereof |
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- 1997-06-25 CN CN97112562A patent/CN1092076C/en not_active Expired - Fee Related
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| CN87104309A (en) * | 1986-05-20 | 1988-03-02 | 煤气技术研究所 | The method of removing sulphur compound when the carbonaceous solids particle gasifies in the fluidized-bed |
| JPS6418431A (en) * | 1987-07-14 | 1989-01-23 | Mitsui Shipbuilding Eng | Denitration method for circulating type fluidized layer boiler |
| CN1103658A (en) * | 1993-07-12 | 1995-06-14 | 凯洛格总公司 | Coal gasification and sulfur removal process |
| CN1110776A (en) * | 1995-03-07 | 1995-10-25 | 中国科学院化工冶金研究所 | No-smoke burning coal method for control nitrogen oxide and stove and application |
| JPH09159101A (en) * | 1995-12-01 | 1997-06-20 | Babcock Hitachi Kk | Pressurized fluidized bed boiler and operation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106215656A (en) * | 2016-09-09 | 2016-12-14 | 成都九十度工业产品设计有限公司 | A kind of ozone mixing reactor |
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| CN1203117A (en) | 1998-12-30 |
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