JPH02229519A - Simultaneous dry desulfurizing and dust-collecting device and its operation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a plurality of moving beds using granular desulfurization and dust removal material, and makes the moving speed of the front stage greater than the moving speed of the rear stage. This article relates to a dry/dry simultaneous desulfurization/dedusting device that simultaneously desulfurizes and dedusts the high-temperature gas by passing the high-temperature gas containing hydrogen sulfide and dust through these moving beds, and its operating method. [Prior Art] When high-temperature gas containing hydrogen sulfide and dust, such as gas produced by coal gasification gas, is used as fuel for combined cycle power generation or molten carbonate fuel cells, the dust in the gas must be removed. , it is necessary to remove most of the hydrogen sulfide. Conventional technology generally involves cooling the gas and purifying it using a wet method. However, with this method, the thermal efficiency decreases due to cooling the gas. Therefore, dry gas purification technology that performs desulfurization and dust removal at high temperatures of 500°C or higher is currently being developed. For desulfurization, the development of fixed-bed or fluidized-bed desulfurization equipment using metal oxide-based granular desulfurization agents, and desulfurization equipment with metal oxides supported on honeycombs, etc., is underway. All of these are characterized by the ability to regenerate the desulfurization agent and use it repeatedly. As dust removal equipment, moving bed dust removal (granular bed filters) using granular filter media and high-temperature filters using metal or ceramic porous bodies or fabrics have been developed. Moving bed dust removal (granular bed filter) allows gas to flow horizontally and the filter material to flow vertically, creating cross-flow contact.
This is a method of removing dust by capturing the dust in the gas into the filter material. Normally, by using particles with a particle size of about 1 to 2 mm as a filter material, it is possible to remove dust up to about several microns. The number of moving beds may be one, but if there are multiple stages in series, the first stage performs rough removal of dust with a high filter medium flow rate, and the second stage performs fine finishing by reducing the filter medium flow rate. Perform dust collection. After coming into contact with the gas, the filter material is separated from dust by mechanical separation or air flow separation, and then recycled back to the top of the dust collector. Regarding filter media, there are not many restrictions in terms of particle shape, particle surface characteristics, etc., and it is possible to use any filter material that has a certain level of strength so as not to powder or wear out inside the device.Usually, cheap silica sand or the like is used. It will happen. The flow rate of the filter material varies depending on the dust concentration in the gas, the dust particle size, the target dust collection efficiency, etc., but it is generally operated within a range of several seconds+/h or less. Dry desulfurization removes hydrogen sulfide from the gas by bringing the gas into contact with a solid (desulfurizing agent) that has the ability to absorb hydrogen sulfide. Metal oxides are commonly used as desulfurization agents, and they react with hydrogen sulfide as shown below, causing desulfurization as the oxygen in the oxide is replaced with sulfur. M.O. +aH. S + bH, → MSy +
clhoIf appropriate metal species and operating conditions are selected, the used desulfurization agent can be regenerated by the oxidation reaction shown below and can be used repeatedly. MSy + aO. → No, I+ bso. There are many metals that have potential as metals, but iron, zinc, etc. are particularly popular due to their sulfidation reactivity and ease of regeneration.
Desulfurizing agents can be in the form of minerals themselves containing the above metals,
Possible options include molded versions of these metals, and products in which these metals are supported on other carriers. There are various methods for contacting the desulfurizing agent and the processing gas, such as fixed bed, fluidized bed, and airflow bed.
It is also possible to use a moving bed. When iron is used as the metal species, it is appropriate to carry out the desulfurization reaction at 400-600°C and the oxidation regeneration at 600-800°C.

The present applicant has developed a reaction tower having a desulfurization/dust collection layer and a lower part of the reaction tower as shown in Japanese Patent Application Laid-open No. 18582/1982 as an apparatus for simultaneously desulfurizing and dedusting coal gasification gas. We have already developed a device consisting of a regeneration tower connected to the regeneration tower and a dust separator connected to the bottom of the regeneration tower, and have applied for a patent. [Problems to be Solved by the Invention] In general, dust separation using a moving bed is performed by roughly removing dust with a high falling speed (moving speed) of the dust removing material in the first stage, and reducing the falling speed of the dust removing material in the latter stage. It is desirable to perform precise dust collection from the beard. Furthermore, in desulfurization using a moving bed, it is necessary to reduce the desulfurization agent depletion rate and bring the desulfurization agent into sufficient contact with the gas to cause the desulfurization reaction to occur. In this way, the falling speed of the dust removing material in the case of dust removal and the falling speed of the desulfurizing agent in the case of desulfurization do not match.

However, in the coal gasification gas desulfurization/dust collector described in JP-A No. 60-18582, the moving bed in the reaction tower is one layer, so it is optimal for both desulfurization and dust removal. The disadvantage is that it is difficult to achieve a flow velocity that is suitable for the flow. The present invention is 1:. It was developed in consideration of the points mentioned above, and the moving bed is provided in several stages in the gas flow direction, and in the first stage, the function of the dust removal ball is exerted in a state where the desulfurization and dust removal material is flowing at a high speed (moving speed). In the latter stage, a dry simultaneous desulfurization/de-sulfurization system is used, which performs its main desulfurization/de-sulfurization function while the desulfurization/dust removal material is flowing at a slow rate.
Get off RL! The aim is to provide 12 information on 4 devices and their operating methods. [Means and operations for solving the problems] In order to achieve the above object, the dry type simultaneous desulfurization/dust removal apparatus of the present invention has multiple stages of moving beds using granular desulfurization/dust removal material, and Desulfurization and dust removal material flow speed (traveling speed) in the moving bed of each stage can be adjusted so that it becomes faster as the front stage moves.The moving bed of the front stage is used mainly for dust removal, and the moving bed of the rear stage is used for desulfurization. An independent discharge machine is installed at the bottom of each stage of the movable bed so that the main movable bed is used. The appropriate flow rate of gas and desulfurizing agent when performing desulfurization in a moving bed varies depending on the operating conditions, but as mentioned above, in general, the flow rate of both gas and desulfurizing agent is slower than in moving bed dedusting.
(longer residence time) is preferable. The purpose of lowering the gas flow rate is to increase the gas desulfurization rate.
In order to lower the gas flow rate, it is necessary to increase the cross-sectional area of the gas flow path, which increases the scale of the apparatus for a given amount of gas to be processed. It is more economical to regenerate the desulfurization agent after raising the sulfur content to a certain level, but if the movement speed of the desulfurization agent is reduced to increase the sulfurization reaction rate, the dust in the gas [if 1 degree is high The amount of dust retained in the layer increases,
The ventilation pressure chamber of the moving bed becomes too large. In such cases, it is necessary to take measures such as using the desulfurizing agent several times before regenerating it without reducing the moving speed. In principle, it is possible to simultaneously perform dry dedusting and desulfurization using the moving bed method, but both methods are not completely unmatched in terms of operating conditions, and each method has its own limitations. Therefore, it is important to determine the most suitable operating conditions that balance the performance, efficiency, and economy of both dust removal and desulfurization. Furthermore, both dust removal and desulfurization are not operated at a constant load, and must be able to respond to independent load changes for both. In the present invention, in order to perform both dust removal and desulfurization efficiently, a plurality of moving beds are provided, and the front section is operated mainly for dust removal, and the rear section is operated mainly for desulfurization.

In the front stage, desulfurization and dedusting materials are added to the amount of gas.
Set it to a large value as long as the layer pressure loss does not increase and dust removal efficiency is maintained. Therefore, although a dust removal effect can be obtained in the front stage, the reaction rate of the desulfurizing agent is not very high. On the other hand, in the rear stage, the movement speed of the desulfurization and dust removal material is reduced in order to increase the desulfurization agent sulfidation rate. Since most of the dust has already been removed in the front stage, the pressure drop will not increase significantly even if the desulfurization/dedusting material is moved at low speed. In the case of two stages, the appropriate front stage/rear stage filter medium flow rate ratio is in the range of 3 to 20. Furthermore, it is also possible to use an intermittent moving bed in the rear stage to perform desulfurization in a fixed bed state. Ensure the required gas residence time in all stages. Therefore, the term "moving bed" in the present invention includes "intermittent moving bed". Figure 1 shows an example where two levels of moving floors are provided. A discharge machine 3 such as a roll feeder is provided at the bottom of the first moving bed 1, and a discharge machine 4 such as a roll feeder is provided at the bottom of the second moving bed 2. The flow speed (moving speed) of the desulfurization/dust removal material is high, and the flow speed of the desulfurization/dust removal material in the second moving bed 2 is made small. 5 is a dust separator, 6 is a variable means such as a damper, 7 is a regenerator, 8, 1 port is a lift pipe, and 11 is a regenerator bypass line. Note that the broken line indicates the flow of gas. The regenerator is also configured to be supplied with an oxidizing agent (oxygen-containing gas). Although FIG. 1 shows a case in which two stages of moving beds are provided in separate bodies, as shown in FIG. 3, a first moving bed 1 and a second moving bed 2 are provided in one body. In some cases, a . 1
2 is for dust! t[i, 13, 14 are regenerators, 15,
16 is a circulation line. In addition, as shown in Figures 2 and 4, dry simultaneous desulfurization and
Get off! ! A precision dust removal section 18 having a filter 17 made of a porous material such as a ceramic filter or a fabric may be connected to the downstream side of the device. In this case, since the degree of dust in the precision dust removal section 18 is extremely small, there is an advantage that the precision dust removal section 18 can be made smaller. Next, the method for operating the apparatus according to claim 1 (method according to claim 3) continuously removes a portion of the desulfurization/dedusting material after being used in the moving bed of the front stage after separating the dust. play,
The recycled desulfurization and dust removal material is first supplied to the last moving bed.
The sulfur is then circulated to the moving bed in the front stage for use, and extracted with a high sulfur content for regeneration.

In the apparatus according to claim 1, it is necessary to make the moving speeds of the desulfurizing and dedusting material significantly different between the front stage and the rear stage. For this reason, it is necessary to separate the circulation systems for the sulfurization and regeneration of the desulfurizing agent into the first and second stages, or to use a single circulation system and change the number of times of recycling between the first and second stages. Therefore, in order to simplify the apparatus, there is only one circulation system, and the method according to claim 3 is an operation method that includes a filter medium circulation method that can exhibit high desulfurization performance. The desulfurization performance of a desulfurization agent naturally decreases as the sulfurization rate of the desulfurization agent increases. Therefore, in moving beds where desulfurization is the main activity, it is desirable to use fresh desulfurization agents with as low a sulfurization rate as possible. On the other hand, the more the desulfurization agent is regenerated after increasing the sulfidation rate as much as possible, the less treatment is required and it is more efficient. In addition, when regeneration needs to be performed at a higher temperature than desulfurization, such as with iron-based desulfurization agents, if the sulfidation rate is above a certain level, the heat of regeneration (oxidation) reaction can raise the temperature to the desired temperature range without external heating. In the case of iron-based desulfurization agents, in the desulfurization agent,
If the sulfur concentration is 3% or more, it is possible to raise the temperature without external heat supply. In the method according to claim 3, among the plurality of movable beds, in the front movable bed mainly for dust removal, the desulfurization and dedusting material is recycled and used, and a part of it is extracted and sent to the regenerator for regeneration. ．． All recycled desulfurization and dust removal material is supplied to the rear movable bed mainly for desulfurization, used only once, and then sent to the front movable bed mainly for dust removal. By doing this, high desulfurization performance can be achieved by the fresh desulfurization and dust removal material in the rear moving bed, while the desulfurization and dust removal material has a high sulfidation rate as it is repeatedly used in the front moving bed. You can then play it. This method will be explained in detail based on FIG. A gas containing hydrogen sulfide and dust is passed through the first moving bed 1 in which a desulfurization/dust removal material moves at a high flow rate to perform dust removal-based treatment. Desulfurization after use in the first moving bed 1
The dedusting material is extracted at high speed by the protrusion ja 3, and a portion is supplied to the dust separator 5 to separate dust and powdered desulfurization/dedusting material, and then introduced into the rehabitator 7 for regeneration. The regenerated desulfurization/dust removal material is supplied by the lift pipe 8 to the second moving bed 2 where the desulfurization/dust removal material moves at a low flow rate,
The gas from the first moving bed 1 is passed through the second moving bed 2 to perform a process mainly consisting of desulfurization. The desulfurization and dedusting material used in the second moving bed 2 is extracted at a low speed by the discharge a4, and
Together with the desulfurization and dedusting material extracted from the moving bed 1 and not introduced into the dust separator 5, it is circulated to the first moving bed 1 by the lift pipe 10. In this way, it is extracted with a high sulfur content and recycled again. In addition,
Although not shown in FIG.
A fresh desulfurization/dedusting material supply pipe is connected to the moving bed 2. The method according to claim 4 is the method according to claim 3, comprising:
After separating the dust from a portion of the desulfurization/dedusting material used on the moving bed in the front stage, a further portion is extracted and regenerated, making the extraction ratio variable. In other words, the front stage → (partial extraction), the regenerator, and the rear stage desulfurization.
A regenerator bypass line is installed in the dust removal material flow path to regenerate only a portion of the desulfurization agent supplied to the rear stage. This method will be explained in detail based on FIG. The desulfurization/dedusting material used in the first moving bed 1 is extracted at high speed by the discharger 3, and a portion is supplied to the dust portion #1 machine 5 to separate the dust and the disguised desulfurization/dedusting material. , only a portion is extracted by a variable means such as a damper and regenerated by a regenerator 7. The desulfurization/dedusting material from the dust separator that is not supplied to the regenerator 7 is supplied to the second moving bed 2 via the regenerator bypass line 11. The other configurations are the same as in the method according to claim 3. Since the method described in Item 4 is configured as described above, the following effects are achieved. fl+ When using a desulfurization/dedusting material that can maintain desulfurization performance even when the sulfidation rate becomes considerably high, this method allows regeneration after increasing the sulfidation rate without changing the operating conditions of the desulfurization/dedusting layer. be able to. (2) When a change in the desulfurization load (such as a change in the concentration of hydrogen sulfide in the gas) occurs, the operating conditions of the desulfurization/dedusting layer can be adjusted by changing the proportion of the desulfurization/dedusting material sent to regeneration using this method. Regeneration can be performed at a constant sulfidation rate without changing it. Conversely, even if the dedusting load changes independently, it can be handled in the same way without affecting desulfurization agent regeneration. In the method according to claim 5, after separating the dust from the desulfurization/dedusting material used in the moving bed of the front stage, most of the material is circulated to the moving bed of the front stage, and the remaining part is recycled. On the other hand, most of the desulfurization and dedusting material used in the rear stage moving bed is circulated as it is to the rear stage moving bed, and after being partially regenerated, it is recycled to the rear stage moving bed. It circulates through the moving bed of the stage and extracts the remaining part from the system. This method will be specifically explained based on FIG. A gas containing hydrogen sulfide and dust is passed through the first moving bed 1 in which a desulfurization/dust removal material moves at a high flow rate to perform dust removal-based treatment. Desulfurization after use in the first moving bed 1
After the dust removal material is extracted at high speed by the discharger 3 and supplied to the dust separator 12 to separate dust and powdered desulfurization/dust removal material, most of the material is transferred to the first moving bed 1 via the WI ring line 15.
At the same time, the remaining portion is supplied to the regenerator 13 for regeneration, and then circulated to the first moving bed 1 via the circulation line 15. On the other hand, the desulfurization and dust removal material after being used on the second moving bed 2, where the desulfurization and dust removal material moves at a small flow rate, is transferred to the discharger 4.
is extracted at a low speed, and most of it is circulated as it is to the second moving bed 2 via the circulation line 16, while a portion is supplied to the regenerator 14 for regeneration, and then recycled to the second moving bed 2 via the circulation line 16. , the remaining portion is extracted from the system and either reused or disposed of.

〔Example〕

Examples of the present invention are given below. Example 1 As a test gas, a gas with the following composition simulating coal gasification gas was prepared and treated with the apparatus shown in Figure 1. Hx: 15% by volume? ot: 10% by volume HtO: 10 11■S: 1500ppm dust:
, 3g/Nnf The desulfurization temperature in the second moving bed is 500°C, and the particle size of the desulfurization/dust removal material is 1.0 to 1. 41 am crushed iron ore was used. Regeneration of desulfurization and dust removal materials is 50% at 600℃
This was done by diluted air oxidation. First, the above gas was treated by the method according to claim 3. 8% by weight of the circulating amount of desulfurization/dedusting material in the first moving bed
was extracted, regenerated, and supplied to the second moving bed. The material balance of gas and desulfurization/dust removal material was as shown in Tables 1 and 2. The hydrogen sulfide concentration in the second moving bed outlet gas had decreased to IOOpp+s. In addition, the dust
3■/Nn in the second moving bed outlet gas? The dust removal rate was 9969%. (Left below) CO:l5' Yes. Example 2 A gas with the following composition simulating coal gasification gas was prepared as a test gas and treated with the apparatus shown in Figure 1. In addition, in Table 2, "first moving bed return J" refers to the part of the first moving bed extraction section that is not supplied to the dust separator, that is, the part A in FIG. 1. Ht: 15% by volume CO: 15 # CO wealth: l O 〃HtO: 1
0' HtS: 3000pp■Dust:
3g/Nn? According to the method described in claim 4, the above gas was treated using the apparatus shown in FIG. The desulfurization temperature, desulfurization/dust removal material, and regeneration conditions were the same as in Example 1. Of the desulfurization/dust removal material extracted from the first moving bed (extraction rate is the same as in Example 1 (8% by weight)), 75% by weight was sent to the regenerator for regeneration. Gas and substances of the desulfurization/dust removal material The balance was as shown in Tables 3 and 4. The hydrogen sulfide concentration in the second moving bed outlet gas had decreased to 100 pp-. The dust removal rate was 99.9%.Example 3 Hydrogen sulfide 1200 ppm, dust 3000 ■/Nnl
Coal gasification gas from a coal gasification furnace containing gas was processed at high temperature using the equipment shown in Figure 2. A ceramic filter was used as the filter made of porous material. The second moving bed outlet gas is hydrogen sulfide 20ppw+
, dust 100■/Nod was included. As a result of introducing this gas into the precision dust removal section and processing it, the hydrogen sulfide in the precision dust removal section exit gas was reduced to zoppm, and the dust was reduced to 0. It was reduced to tppm. This purified gas was supplied and used by the gas turbine. Note that similar results were obtained using the apparatus shown in Figure 4. [Effects of the Invention] Since the present invention is configured as described above, it has the following effects. +11 In the apparatus of claim 1, by integrating the desulfurization section and the dust removal section, the apparatus can be made smaller and simpler, and the amount of power and utilities used can be reduced. In addition, it is possible to adopt optimal operating conditions that balance the performance, efficiency, and economy of both desulfurization and dust removal.

<<2>> In the apparatus of claim 2, since the amount of dust at the inlet of the precision dust removal section is extremely reduced, the precision dust removal section can be downsized. (3) In the method of claim 3, in the moving bed at the last stage, the desulfurization/dedusting material with a low sulfur content exhibits high desulfurization performance, and the sulfur content in the desulfurization/dedusting material is reduced. After increasing the value, it is possible to regenerate efficiently. (4) In the method of claim 4, the applicable load range for each of desulfurization and dust removal is wide, and it is possible to cope with variations in both independently.

(5) In the method of claim 5, independent circulation lines for desulfurization and dust removal materials are provided in both the moving bed mainly for dust removal and the moving bed mainly for desulfurization, so that dust separation and Playback can be performed efficiently.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the dry type simultaneous desulfurization/dust removal apparatus of the present invention, and FIGS. 2 to 4 are explanatory diagrams showing other embodiments of the apparatus of the present invention. 1... first moving floor, 2...
2nd moving bed, 3, 4... Ejector, 5, 12... Dust separator, 6... Variable means, 7, 13, 14... Regenerator, 8, 10... Lift pipe , 11... Regenerator bypass line, 15, 16... Circulation line, 17.
...Filter made of porous material, 18...Precision dust removal section

Claims (1)

[Claims] 1. A plurality of moving beds using granular desulfurization/dust removal material are provided,
The descending speed of the desulfurization/dust removal material on the moving bed of each stage can be adjusted so that it increases as the front stage moves.The moving bed in the front stage is a moving bed mainly for dust removal, and the moving bed in the rear stage is a moving bed mainly for desulfurization. A dry type simultaneous desulfurization and dust removal device characterized by having an independent ejector installed at the bottom of each stage of the moving bed. 2. A dry simultaneous desulfurization/dust removal apparatus, characterized in that a precision dust removal section having a filter made of a porous material is connected to the downstream side of the dry simultaneous desulfurization/dust removal apparatus according to claim 1. 3 After separating the dust from a part of the desulfurization/dust removal material used on the moving bed in the front stage, the part is continuously regenerated, and the recycled desulfurization/dust removal material is first supplied to the last stage moving bed, A method for operating a dry simultaneous desulfurization/dedusting device, which is characterized in that the sulfur is then circulated to a moving bed in the front stage for use, extracted with a high sulfur content, and regenerated again. 4. Claim 3, characterized in that a part of the desulfurizing/dedusting material used in the moving bed of the front stage is separated from dust, and then further part is extracted and regenerated, and the extraction ratio is made variable. How to operate the dry simultaneous desulfurization and dust removal equipment described. 5 After separating the dust from the desulfurization/dedusting material used in the forward stage moving bed, most of it is circulated to the forward stage moving bed, and the remaining part is recycled, and then transferred to the forward stage moving bed. On the other hand, most of the desulfurization and dedusting material used in the rear moving bed is circulated as is to the rear moving bed, and a portion is recycled and then circulated to the rear moving bed. ,
A method of operating a dry-type simultaneous desulfurization/dedusting device characterized by extracting the remaining portion out of the system.