JPS58207928A - Composite reactor for desulfurization and denitration - Google Patents

Abstract

PURPOSE:To reduce an installation area, by flowing waste gas to the upper part of a reactor from the lower part thereof to improve mixing in an up-and-down direction in the reactor. CONSTITUTION:Waste gas is supplied to the inside gas passage provided to the lower stage of a reactor and contacted with activated carbon so as to cross the same at right angles to be desulfurized. The desulfurized gas is raised through the outside gas passage while mutually mixed with gases passing the upper part, the intermediate part and the lower part of a lower stage moving layer to be homogenized and, after the resulting gas mixture is injected with ammonia, it is contacted with activated carbon in the upper stage of the reactor so as to cross the same at right angles top be converted to the denitrated gas which is in turn exhausted through the inside gas passage. Desulfurization is carried out in the lower stage of the reactor while denitration in the upper stage thereof and the adsorbent supplied from the to part of the upper stage is fallen through the moving layer and reaches the lower stage moving layer through a seal part to be able to be taken out to the outside through an exhaust port.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite reactor for desulfurization and denitration having a desulfurization section and a denitrification section.

Exhaust gas from zein, which burns sulfur-containing fossil fuels, or sintering machines, which sinter sulfur-containing ores, contains soot, sulfur oxides, nitrogen oxides, etc., and must be collected for environmental protection. , desulfurization, denitrification, etc. Desulfurization and denitrification are generally carried out separately, and the wet limestone/gypsum method, dry activated carbon method, etc. have been put into practical use as desulfurization methods, and the catalytic reduction method has been put into practical use as the denitrification method. As a method for desulfurizing and denitrating exhaust gas in the same process that combines these methods, a method using a carbonaceous adsorbent under injection of ammonia is known, and a method for simultaneous desulfurization and denitration using a single packed bed reactor is known. A method has been proposed in which desulfurization and denitrification are performed separately by combining several stages of unfilled reactors. The former requires only a single photovoltaic bed, making it possible to construct a complete system, but if a relatively high concentration of SOx (more than 500 ppm) coexists, 3
Only a denitrification rate of about 0 to 40% can be obtained, and supplementary denitrification is only possible.

On the other hand, the latter method performs denitration after desulfurization, so it is possible to achieve a high denitration rate of about 80%, and this method will likely become the mainstream desulfurization and denitration method in the future.

However, this method has problems that must be solved in practice. The reason is that since two reactors are usually combined, the amount of adsorbent used and the installation area are larger than in the one-stage system described above.

Regarding the problem of the amount of adsorbent to be used, the inventor of the present invention solved the problem of adsorbent using a. We proposed that the amount of adsorbent used could be reduced while maintaining high desulfurization and denitrification rates by circulating the adsorbent from reactor 1 to regeneration tower 2 to second reactor 3 to first reactor 1. o6604
8), but the issue of installation space remained unresolved.

On the other hand, the basic structure of a reactor is known to be a simple system, but the process of processing a large volume of exhaust gas is called a cross flow (or cross flow), in which the exhaust gas and the filling material that descends due to gravity are orthogonal to each other ( The contact method (or cross-shaped) is suitable because it requires less installation space and can be made into a connoct, and is the mainstream in practical processes.

One of the important characteristics of this cross-flow moving bed is that desulfurization and denitrification are sufficiently carried out in the upper part of the packed bed, but insufficiently in the lower part.
0x and NOx concentration distributions occur, and in the upper part NOx,
It is known that both Box and 8 degrees are low and both become high in the downward direction.

(Refer to JP-A-55-106526) Therefore, in the method of performing desulfurization and denitration in the two-stage reaction process, when both reaction processes are connected, the upper and lower parts of the exhaust gas at the outlet of the first stage are sufficiently mixed to reduce the Sox and NOx concentration levels. It is necessary to average it out and keep it low so that denitrification can be carried out effectively in the later reaction process.

For this reason, it is necessary to provide some kind of exhaust gas mixing section between the two reactors, which is an obstacle to reducing the installation area. For example, in the method disclosed in JP-A-56-163739, a partition wall is provided between both reaction steps in an integrated reactor, and as a result, the exhaust gases are mixed in the vertical direction. However, since both reaction steps are arranged on a flat surface, the installation area cannot be made very small.

The inventor of the present invention noticed that in the process shown in Figure 1, the flow of adsorbent and the flow of exhaust gas are countercurrent, and as a result of various studies, he integrated two reactors by stacking them one above the other. By using one reactor and flowing the exhaust gas from the bottom to the top of the reactor, the problems of mixing the exhaust gas in the vertical direction of the reactor and the installation area were resolved at once.

That is, in the present invention, a carbonaceous adsorbent moving layer is connected to the outer casing 1. An outer gas passage is formed between the outer casing and the absorbent IMi1 moving layer, and an inner gas passage is formed inside narrowed by the adsorbent moving layer, and a lateral gas cutoff is provided near the gas seal part. A plate is provided in the inner gas passage or the outer gas passage to divide the inner gas communication passage or the outer gas passage into upper and lower stages, and the outer case,
The sink is provided with a gas discharge port that communicates with the upper gas passage and a gas supply port that communicates with the lower gas passage, and an ammonia pressure inlet is opened in the unblocked gas passage near the gas seal. , an adsorbent supply port is provided in the upper part of the adsorbent moving bed, an adsorbent outlet is provided in the lower part, and the side wall of the moving bed in contact with the outer and inner gas passages, excluding the gas seal part, is characterized by having a 3M temper. It is.

Next, the configuration of a reactor according to an embodiment of the present invention will be explained with reference to one drawing. , the reactor has the second to fourth iK 1
#Lh, this is a structure in which tips for moving adsorbent through carbon, which are connected to an upright part via a gas seal part 4, are housed in an outer casing 6. An outer gas passage 7 is formed between the outer casing 6 and the adsorbent transfer layer 5, and an inner gas passage 8 is formed inside the adsorbent transfer nozzle 5. Further, a gas cutting plate 9 shown in a lateral view is provided in the inner gas passage 8 near the gas seal portion 4, and the inner gas passage is divided into two upper stages,
The outer casing 6 is provided with a gas discharge port 10 communicating with the inner gas passage 8 in the upper stage and a gas supply port 11 communicating with the inner gas passage 8 in the lower stage. In the unblocked outer gas passage 7 near the gas seal part 4, there is an ammonia inlet P.
Let's open it. An adsorbent supply port 12 is provided at the top of the adsorbent transfer layer 5, an adsorbent discharge port 13 is provided at the bottom, and a discharge device 14 such as a roll feeder is installed. Further, in order to uniformly flow down the adsorbent, it is desirable to provide a flow regulator 15 above the gas seal portion 4 and above the adsorbent outlet 13. Except for the gas seal portion 4, both side walls of the moving layer in contact with both gas passages are composed of air permeable plate-like bodies such as external hole plates and loopers. In addition, 16 indicates a rotary valve, and 17 indicates a hot spring.

According to the examples shown in Figures 2 to 4 above, the exhaust gas is supplied to the inner gas passage in the lower stage of the reactor, contacts the activated carbon in a cross-flow form, and is passed through the desulfurizer (Figures 2 and 4). (See Figure 4). While the desulfurized gas rises through the outer gas passage, the gases that have passed through the upper, lower, and intermediate portions of the lower stage M layer are mixed and averaged, and after ammonia is injected, activated carbon is produced in the upper stage of the reactor. The gas is denitrified by contacting the gas in a cross-flow manner and is discharged through the inner gas passage (see Figures 2 and 3).

On the other hand, the embodiments shown in FIGS. 5 to 7 show a case where a horizontal gas blocking plate 9 is provided near the gas seal portion 4 of the outer gas passage 7 to divide the outer gas passage 7 into upper and lower stages. In this case, the ammonia inlet P is opened into the unblocked inner gas passage 8 near the gas seal portion 4 . The outer casing 6 also has a gas exhaust port 10 communicating with the upper outer gas passage 7 and a gas supply port 11 communicating with the first outer gas passage 7.
will be provided. .

Therefore, the exhaust gas is supplied to the outer gas passage in the lower stage of the reactor, and is desulfurized by contacting the activated carbon in a cross-flow form, and the desulfurized gas passes through the inner gas passage, after which ammonia is injected, and then in the upper stage of the reactor, it is sent to the activated carbon. It is denitrified in cross-flow contact with the gas and discharged through the outer gas passage.

In the above example, the reactor and moving bed were square in planar cross-section, but there is no difference in the effect even if they are cylindrical, and the supply of adsorbent to the top of the moving bed is 1. A so-called spider leg system may also be used in which pipes are branched from two pipes and opened downward.

In the present invention, the gas seal portion is an important component. If you don't install a gas seal, move it! - Due to the pressure difference between the front and rear, untreated gas passes through the moving bed to the gas outlet side, making it impossible to obtain a high denitrification effect. Therefore, a gas seal section is provided to prevent the untreated gas from passing due to the ventilation resistance of the seal section.

Furthermore, although it is sufficient for the gas seal part to be a material seal made of the adsorbent itself, Fig. 8 shows a case in which complete sealing is achieved by a rotary valve (corresponding to the embodiments shown in Figs. 2 to 4). In this case, it is necessary to provide an adsorbent discharging machine 13 such as a roll feeder at the bottom of the upper moving bed, and it is necessary to interlock with the adsorbent discharging machine 14 provided at the bottom of the f-stage moving bed.

As is clear from the above explanation, in the present invention, desulfurization is performed in the lower stage of the reactor, and denitrification is performed in the upper stage of the reactor, and the adsorbent supplied from the top of the upper stage descends through the moving bed and passes through the seal section. Since the reactor can reach the lower moving bed and be taken out to the outside through the discharge port, one reactor can sufficiently perform the functions of the two reactors in the process shown in FIG.

Therefore, it has the great advantage of reducing the installation area by half, making it the same area as the conventional single reactor system.
Furthermore, there is no need for a conveyor to transfer the adsorbent from the denitrifier to the desulfurizer. There is also the advantage of reducing equipment costs, such as eliminating the need for ducts to connect both reactors.

The above embodiment can be seen as a type of modular reactor, and when handling a large amount of exhaust gas, multiple modules can be arranged vertically or horizontally, and the partition walls between each module can be removed. . Figure 9 shows an example of this, in which six unit modules are integrated, and are arranged regularly to facilitate gas distribution and adsorbent distribution and supply. It looks like a compact structure. Note that FIG. 9 is a plan view, where solid arrows indicate gas passing through the lower moving layer, and broken arrows indicate gas passing through the upper moving layer.

[Brief explanation of drawings]

FIG. 1 shows a flow sheet for the desulfurization and denitrification process. FIG. 2 is a longitudinal cross-sectional view of a composite reactor for desulfurization and denitrification which is an embodiment of the present invention, FIG. 3 is a horizontal cross-sectional view taken along line A-A in FIG. 2, and FIG. FIG. 3 is a horizontal sectional view taken along line BB in FIG. 2; FIG. 5 is a longitudinal cross-sectional view of another embodiment of the present invention, FIG. 6 is a horizontal cross-sectional view taken along line 0-C of FIG. 5, and FIG. It is a horizontal cross-sectional view taken along the DD line. FIG. 8' shows an example of the structure of the gas seal section according to the present invention. FIG. 9 is a horizontal sectional view showing another embodiment of the present invention. 4... Gas cool section 5... Carbonaceous adsorbent moving layer 6
...Outer casing 1...Outer gas passage 8...Inner gas passage 9...Gas sill plate 10...Gas discharge port 11...Gas supply port 12...Adsorbent supply port 1
3...Adsorbent discharge port 14...Discharge machine 15.
...Fluid regulation 16...Rotary/Trube patent applicant Sumitomo Heavy Industries, Ltd. Mon 5 Kasumi

Claims (1)

[Claims] 1. A carbonaceous adsorbent transfer layer, which is connected to an upright portion through a gas seal, is housed in an outer casing, and an outer gas passage is formed between the outer casing and the adsorbent transfer layer to allow adsorbent transfer. If an inner gas passage is formed on the inside narrowed by the layers, a horizontal gas shielding plate is provided in the inner gas passage or the outer gas passage near the gas seal part, and the inner gas passage or the outer gas passage is divided into upper and lower stages. For the outer casing, a delayed gas discharge port is provided in the upper gas passage and a delayed gas supply port is provided in the T-stage gas passage, and an ammonia inlet is provided in the unblocked gas passage near the gas seal. Open (°provide an adsorbent supply port at the top of the adsorbent transfer layer and an adsorbent discharge port at the bottom, and make the side wall of the 7P transfer 4 in contact with the outer and inner gas passages permeable, excluding the gas seal part). Features: Cross-flow type composite reactor for desulfurization and denitrification