JPH06511290A - Separation method and apparatus for separating molten particles from a gas stream - 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] Separation method and apparatus for separating molten particles from a gas stream Technical background The present invention provides a method in which the gas stream is a waste liquor, preferably black liquor, produced in pulp production. contains both gaseous and molten materials, and may also contain from a gas stream that also contains solid particles. The present invention relates to a separation method and apparatus for separating unknown solid particles.

to recover the substances contained in the process and the energy added or released during the process. The demands of various processes have been constantly increasing. These demands are mainly related to the environment. It has been done for related and economic reasons. A common problem is that certain professional In a process, a gas mixture containing both melt and vapor phases is obtained. Ru. The gas mixtures are used for the recovery of their contents chemical products and energy. Difficult to handle. Particularly problematic are melt particles. Because the heat In the exchange process, melt particles are often deposited on the convection surfaces of the heat exchanger. It is et al. This is not desirable. This problem is 5E-8- 328179.

Examples of industrial process areas where this type of problem arises include the use of paper valves in the manufacture of paper valves. Includes gasification of used liquor. Gasification of spent liquor takes place in a reactor . The organic material contained in the used liquor decomposes thermally and partially burns, resulting in , thermal energy can be obtained and chemical contents can be separated to recover Can be done. Hereinafter, the present invention will be specifically explained regarding the gasification of black liquor. However, the present invention is not limited thereto.

Black liquor is a residual product in valve manufacturing by the sulfate cellulose process. Obtained as a used car. Black liquor is a form of various sodium compounds. Contains alkaline chemicals. It can be recovered for reuse in the process is desired. The recovery process includes a heating step and a reactor, in which black liquid is Chains of organic molecules in the car decompose into energy-rich gases, and the inorganic contents are mainly exists as melt particles that can be recovered. This is an organic compound in black liquor produced by thermal decomposition and partial ashing. Pyrolysis and ashing release thermal energy , the temperature is typically around 1000'C in the reactor, producing flammable gases. released It is desirable to recover the heat generated and use this energy-rich gas as fuel. It will be done.

5E-B-448173 includes the recovery of chemicals and energy from black liquor. It describes how to do so. 5E-B-448173, a considerable amount of Eliminates deposition problems by recovering heat and at the same time passing the gas directly through the liquid layer. I was able to avoid it. taken up by said liquid, which may be melt particles or green liquor. As it is raised, the gas is cooled at the same time. Fluid bath free of melt particles The gas leaving the gas has a temperature of approximately 80-9°C in a non-pressurized system. One. This temperature corresponds to the approximate temperature of the green liquor bath. Thus, in this case , a melt-free gas flow of about 9o''C and a fluid bath of about 90'C are obtained.

From an energy recovery perspective, these temperatures are too low to be optimal. The reason In suitable cases, the superheated steam Is it desirable to transfer heat at a higher temperature level so that it can be obtained in the form of air? It is et al. Superheated steam is supplied at high pressure and temperature, e.g. 150 bar and 600°C. Maximum efficiency of steam turbine operation is obtained when the Thus, heat exchange is not possible. However, in the above method, the gas is heated at approximately 100° C, or this makes efficient heat recovery impossible. Reason above Obviously, it is desirable to extract the heat at high temperatures so that it can be recovered in the form of superheated steam. That's it. The recovery method from used liquor is also described in 5E-8-363651. is also known. In this method, the gas from the reactor is more than optimal in terms of recovery. is cooled to a level that is too low.

Solution and benefits The first object of the invention is to melt the melt from the gas stream without significantly lowering the gas temperature. The object of the present invention is to provide a method and apparatus for separating and making available particles.

The above object is achieved according to the invention by a method according to claim 1 and a device according to claim 7. i.e. the stream of gaseous material containing the particles is caused to move along a curved path. so that at least the outer periphery of the curved passageway is defined by a movable liquid layer, and the particle is separated from the gas stream by being amalgamated with the liquid layer. achieved by.

It is generally known that a "liquid film cyclone" is used. , but in reality it is not possible. For example, this type of cyclone that separates solid particles is υ5-A-793110 (υehling), US-A-2259034, etc. It is known from However, such known cyclones are particularly suitable for cellulose waste. It is intended for the separation of melt particles that result in coalescence other than that which occurs in the gasification of melts. This is not shown in the figure and therefore causes failure after the fusion period of the hardening melt particles. Has partial components. Such malfunctions are avoided by the device of the present invention.

Another object of the invention is that carbonate formation in the melt particles causes separation of the melt particles at high temperatures. By carrying out, the sodium hydroxide content is delayed and therefore the high The CO2 content is separated before it has time to combine with the sodium.

An additional object of the invention is that at least one sulfur-free and at least one Enables the separation of selectively extracted organic chemicals in sulfur-containing streams Grids with various Na/S ratios (suffhidity) can be The aim is to facilitate the production of alcohol.

Another object of the invention is to convert the melt granules into active cooking chemicals, namely NaOH and NatS. The purpose is to provide a method that can directly convert children.

Yet another object of the invention is to provide a gasification reactor with, inter alia, a preheated gas; For example in the form of air or alternatively in the form of superheated steam, preferably up to about 150 bar. pressure and temperature up to about 600″C (this is independent of the reactor operating pressure) ) allows other methods to be used to recover the significant heat content of the gas The goal is to provide a way to do so.

Drawing description The invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a side perspective view of a preferred embodiment of the invention with a portion cut away.

2 is a horizontal sectional view of the apparatus of FIG. 1; FIG.

3 is a diagram of a somewhat modified embodiment of the apparatus of FIG. 1; FIG.

FIG. 4 shows a basic process plant with two devices of the present invention.

FIG. 1 shows a reactor l connected directly to the apparatus 2 of the invention.

This device will be referred to hereinafter as a liquid membrane cyclone. In the illustrated example, the device is black. Used in connection with the extraction of chemical products and energy during clicker gasification. bra Liquor is the residue obtained during cooking in valve manufacturing using the sulfate cellulose process. It is a distillate product. Reactor 1 has a first inlet conduit 3A for black liquor and a first inlet conduit 3A for air. A second artificial conduit 3B is connected thereto. In the reactor, the thermal decomposition of black liquor and the partial Target ashing occurs. During this process, it contains part of the gas part and part of the melt. A gas mixture is created. The temperature in the reactor is usually 800°C to 1500°C. Ru.

The chemical melt is then present in the gas 4 in the form of drops 5. Mixture of gas and melt 4 ．． 5 is continuously introduced into the hydrocyclone 2 through the reactor 1. liquid cyclo The inflow into the tube 2 is tangential to the cylindrical wall of the hydrocyclone 2.

The hydrocyclone 2 consists of a casing 6.7.8 with an outlet 9 at the bottom. about 10 0°C (this temperature can be increased if the pressure in cyclone 2 increases) A liquid, e.g. water (H2O) or dilute liquor, at a temperature of is conveyed to the hydrocyclone 2 via a distribution conduit 11 connected to it at the top 8 of the . A guide rod 15 is installed inside the liquid membrane cyclone 2 to distribute and guide the liquid layer I2. Placed. The liquid film cyclone 2 has its longitudinal axis 13B extending in a vertical plane. It is placed like this.

A gas removal vibrator 14 is attached to the outlet opening in the top gable 8.

The basic functions of the device of the present invention are as follows. Both gas 4 and melt particles 5 The hot gases 4.5 containing them flow out of the reactor 1 at a relatively high velocity. This flow is tangential It is brought into the liquid film cyclone 2 in a direction and in a substantially horizontal direction. In this regard , whose cardiac acceleration (F=mv”/2r) ensures the separation of melt particles from the gas stream. Ru. This is because melt particles are heavier than gas. Therefore, the melt particles and is captured in the liquid stream 12. On the other hand, gas 4 It moves in a spiral toward the opening in the gable 8 at the top, and is carried forward via the vibe 14. It will be done. During this process, the gas is in contact with the liquid film for a very short time. Furthermore, gas Only a relatively small portion is in direct contact with the liquid film. As a result, relatively small heat transfer occurs from the gas to the liquid film. Therefore, the gas 4 in the vibrator 14 has a relatively high temperature, making it suitable for In such cases, the temperature decreases by only about 100-500°C. Gasification is substoichiometric Since the process is carried out under a theoretical oxygen supply, the gas produced contains a sufficient proportion of hydrogen gas. Contains flammable components such as gas (H2), -carbon oxide (CO) and methane (CH,). nothing.

The melt particles picked up by the liquid in the liquid film are, in a preferred embodiment, 2, it is first cooled down and thereby dissolved in the liquid, and then the liquid film is transferred. As a result of the movement, it is carried downwards with it into the liquid film cyclone 2. insoluble Components of the solid or melt are also taken up by the liquid. Take this way The lifted particles, either in dissolved or undissolved form, pass through the opening at the bottom of cyclone 2. is led out from the cyclone 2 through the outlet 9 of the cyclone.

As is clear from FIG. 1, the cyclone 2 of the preferred embodiment has a gentle conical shape. It has a central section 7. The reason for the gentle conical shape is to compensate for liquid evaporation. It is. The hot gas 4, together with the melt chemical particles 5 in its contents, preferably Upon encountering a liquid film 12 consisting of a liquid with a boiling point below that of water (e.g. water), the Some evaporation occurs. Nevertheless, a certain predetermined thickness of the liquid film 12 is maintained. Therefore, since part 7 of cyclone 2 is made into a gentle conical shape, the result is Despite the fact that the volume of the fruit liquid 12 decreases during its downward movement, it has a practically constant thickness. A liquid film is obtained.

As is further evident from FIG. 1.2, the liquid film cyclone 2 has a longitudinal guide rod 1. 5 can be installed. As mentioned above, the purpose of this guide rod 15 is to specifically detect the presence of a liquid film. In order to ensure and prevent the strong flow of gas and melt 4.5, the liquid layer 12 is It is to distribute and guide.

In a possible working example, the reactor temperature is about 950°C and the system pressure is about 30 bar. It is a rule. Due to the pressure of the system, a thin liquor or In this case, water is used as the membrane liquid 12. In this example, the gas exiting liquid film cyclone 2 is The temperature of the bath is approximately 600°C to 700°C, which is overheated during subsequent heat exchange. Advantageous for generating steam.

FIG. 3 shows another embodiment of the device according to the invention. Similar to liquid membrane cyclone 2, the reactor l in this case has a vertically oriented longitudinal axis. In this case too, black liquor The gasification of is preferably effected by pyrolysis and subchemical supply of oxygen. gas 4 and melt particles 5 are led from the reactor l to the liquid membrane cyclone 2 via the connecting conduit 16. It will be done. Said conduit diverts the flow and runs tangentially and substantially horizontally within the hydrocyclone 2. so that it flows into the In other respects, the construction of this device is essentially the same as that described above. It is the same. Therefore, for example, in this case as well, the distributor 11 and the guide rod 15 are arranged to provide a desired thickness of liquid. It will be clear that it is used to secure body membranes within the appropriate area.

Figure 4 shows the content of chemical products in black liquor measured using the device of the present invention. 1 shows an example of the basic parts of a process plant for energy recovery;

The plant consists of a reactor l into which black liquor is conveyed via conduit 3A. . Black liquor has a temperature of about 130°C to 190″C and about 65% to 85% dry matter. It has a content. Prewarmed secondary air with a temperature of approximately 500″C to 700′C is 2 through conduit 3B. Two-stage system for separating melt particles from gas stream 4 The process consists of two first liquid membrane cyclones prepared for high temperature first separation. , in a plant where a second liquid membrane cyclone 2B is prepared for a low temperature second separation. It is used in This reduces the concentration of liquid removed from each cyclone. , which can be varied by differences in separation temperature, at least to the extent that the measurement This is advantageous because it can be done.

Gas 4 with melt particles 5 exits reactor l into first liquid film cyclone 2A. and at that junction a first separation occurs as described above. This first liquid film The gas 4 leaving Iklon 2A contains an amount of gasified sodium compounds and is It is guided to the second liquid film cyclone 2B via 14A. After this second separation step Then, the gas free of melt particles is led to the first heat exchanger 18B. Therefore, the heat Gases 4 release part of their heat content. For example, this is a temperature of about 600°C. It is suitably extracted as superheated steam with a pressure of approximately 150 bar. heat exchanger 18 Before entering, the hot gas has a temperature of about 600°C to 800°C.

After passing through the first heat exchanger 18, the gas 4 first enters the Venturi scrubber 19; The gas 4 is then guided into the nozzle washer 21 and then exited via the conduit 22. It will be done. As a result of the high degree of gas purification carried out by this technique (<1 pp m-alkali), which is used, for example, as a fuel for gas turbines for efficient power generation. I can do something. The relatively weak alkaline solution is preferably used for washing in the nozzle washer 21. Used as a cleaning liquid. The liquid obtained from the nozzle washer 21 through the conduit 35 is Preferably used during venturi cleaning.

The first liquid film cyclone 2A has two separate outlets 23A and 26A at the bottom. Placed. The first outlet 23A is used to convert the subsequent raw material into digester house chemicals. Designed to collect. The green carcasses collected in this way are pumped through the conduit 25. 24 into a collection container (not shown). First liquid film cyclone 2A A second outlet 26A obtained from the be given In order to continuously replenish the liquid 12 into the liquid film, the conduit is filled with liquid, i.e. raw material. The liquid car is guided to the top of this first liquid film cyclone 2A. Heat exchange in this circuit 28 A portion of the heat of the raw carcass is recovered by the vessel 18A.

The liquid taken out from the second liquid membrane cyclone 2B via the conduit 23B is pumped 32. is circulated in circuit 28B by.

Also in this circuit 28B is a heat exchanger 18C, which provides for recirculation. Thermal energy is recovered from the raw car before it is heated. Furthermore, the liquid supply conduit 28C is It is connected to this circuit 28B. A conduit 29 leads out of this circuit 28B and is connected to the first circuit 28B. It is connected to the circulation circuit 28A of the Ikron 2A. This conduit 29 is connected to the first cyclone 2 Used to supply liquid to A. The green carcasses are removed from the nozzle washer 21. (pump 36) for storage in a collection container (not shown).

The present invention is not limited to the above embodiments, and various modifications may be made within the scope of the claims. It is possible. For example, the operating pressures illustrated above are not limited to system pressure depends, among other things, on the required evaporation temperature of the membrane liquid. It can be varied by approximately 150 bar.

The expression “surrounding a casing or free space” refers to an area that is not submerged in water. This means that there is no component placed within the casing at a distance of . Therefore, clumping melt particles can accumulate and form a coating that impairs functionality. do not have.

This is an important feature of the invention.

The gasification temperature, i.e. the temperature in the reactor at which pyrolysis occurs, is above about 500°C. Can be within a wide temperature range. However, the most suitable range is 800°C to 16 00°C, or more preferably 800°C-1400°C. Gasification is 5 Occurring within the range 00°C to 800°C, the crystals rather than the melt particles become gas Obtained within the flow. Therefore, processes within these temperature limits are also called “dry methods.” It will be revealed. If the temperature in the reactor is between 800°C and 1000°C, the inorganic In the form of droplets of melt, i.e. sodium carbonate (Na2CO2) and sodium sulfide ( It exists in the form of NazS). At high temperatures starting from about 1000°C the carbonate form formation is prevented, so processes at temperatures higher than about 1000°C will cause causticization. Alkali can be recovered without straining.

The basic requirements that make this possible are high temperatures in the reactor and It is suitably within the range of 1200°C to 1500°C. The reason is that high This is because, at higher temperatures, the carbonate content of the resulting green curd is greatly reduced. The reason is , the equilibrium relationship of the following reaction equation, that is, Na2S + COz + H20H2S + Naz COs and 2NaOH + CO2N at　Cot　+H20 shifts significantly to the left side reaction formula at high temperature, and the separation is at this high temperature. This is because it occurs at the temperature level.

In a preferred embodiment, gasification occurs substoichiometrically, which is due to the This means that insufficient oxygen is supplied for complete combustion of the material.

Therefore, flammable gases such as hydrogen gas (H2) and carbon oxide (Co) are produced. . In a preferred embodiment, about 50% acid is added to the theoretical requirement for stoichiometric combustion. Raw material is supplied. However, as will be clear to those skilled in the art, this can vary within wide limits. I can do it.

Furthermore, as will be clear to those skilled in the art, the conical shape of the liquid film cyclone is a preferred example. , and the method of the present invention provides a cylindrical structure if a sufficient thickness is given to the liquid film from the beginning. Shaped casing surfaces can also operate, thus resulting in a constant thickness of evaporation. It is possible to tolerate a decrease. Guide rods also provide suitable examples. Gas flow applied to liquid film The effect of This can be compensated for by guiding membrane flow. The placement, size, and shape of the guide rod It depends on the size and velocity of the gas flow and the dimensions of the cyclone. Furthermore, the casing It is not necessary to apply a liquid film to the entire inner surface of the Of course it is.

The temperature of the liquid in the liquid film cyclone can be varied within wide limits. temperature with Factors that influence the selection of requirements (if particles are dissolved in a liquid, the rate of dissolution is temperature dependent and therefore to some extent are measurement factors), operating pressure, casing surface size, The gas flow rate, its temperature and many other considerations.

Instead of recovering the significant heat content of the gas as superheated steam, its heat content naturally can be extracted in other forms, e.g. preheated combustion air for the reactor. Ru.

Treatment of gases in nozzle cleaners or cleaner systems to remove chemical residues is also of course a suitable process. Cleaning is done in part for environmental reasons, i.e. Some are carried out to remove impurities from subsequent emissions and some for technical operational reasons. It will be done.

Also, without any secondary air supply, i.e. no oxygen or oxygen-containing gas is supplied externally. It is true that black liquor can be gasified without being supplied with It will be obvious to business owners. In that case, only thermal decomposition occurs.

Finally, the use of the device according to the invention for the gasification of black liquor is only an example. I would like to point out again that this is an indication. The liquid film cyclone 2 of the device of the present invention is preferably such as those requiring the separation of melt particles from a hot gas stream, and For use in all areas where the effect on the temperature of the gas stream is minimized. I can do it. Furthermore, it is clear that the illustrated structure is not intended to limit the invention. Dew.

The means for dispensing the liquid 12 through the inlet 11 are, firstly, simply the inlet 12. The apertures, i.e., their shape and arrangement. However, fixed blade type distributors It will be apparent to those skilled in the art that this is one of the many known means available.

Instead of taking the gas stream directly from the reactor, a hot gas separator (no liquid layer) +> The heat is taken out from 900°C and given to a heat exchanger before being put into the hydrocyclone. You can do as you like.

Copy and translation of written amendment) Submission (Article 184-7, Paragraph 1 of the Patent Act) January 7, 1994 Day

Claims (1)

[Claims] 1. The gas stream is a gas stream of spent liquor from pulp production, preferably black liquor. oxidation, containing both gaseous substances (4) and melts, and possibly Also containing solid particles (5), said gas stream is led to a separation device (2) where the melt at least some of the particles and possibly solid particles (5) the melt from the gas stream (4), preferably the majority separated from the gas stream (4); Preferably, in a separation method that also separates solid particles, the gas containing the particles (5) A stream of solid material (4) is caused to move through a curved passage, at least one of said curved passages. The outer periphery is defined by a movable liquid layer (12), and the particles (5) are arranged in the liquid layer (12). 12) and is separated from the gas stream (4) by being amalgamated with Separation method used as a sign. 2. The average temperature Tg of the gaseous medium (4, 5) significantly exceeds the average temperature Tv of said liquid layer. above, where Tg-Tv >100°C, preferably >200°C, more preferably >30°C A claim characterized in that the temperature is 0°C, preferably within the range of 400 to 1300°C. 1. Separation method for separating melt and/or solid particles from a gas stream according to claim 1. 3. The liquid stream resulting from the liquid layer (12) is preferably primarily dissolved in a liquid. for extracting the heat content in the melt and/or solid particles (4) and/or in the liquid; From the gas stream according to claim 1, characterized in that the gas stream is at least partially collected in Separation method for separating melts and/or solid particles. 4. at least a portion of the liquid stream originating from the liquid layer (12) is recycled; From the gas stream according to any one of claims 1 to 3, characterized in that A separation method for separating solid particles. 5. Said hot portion in the purified gas stream (4) is preferably superheated steam and/or preheated Gas stream according to claim 1, characterized in that it is recovered by heat exchange as a gas. Separation method for separating melt and/or solid particles from. 6. Spent liquor resulting from pulp production for carrying out the method according to claim 1 , preferably from the gas stream generated from the gasification of black liquor. A separation device that separates solid particles that may be contained in a melt. and gaseous substances (4) containing solid particles (5) that may possibly be included. ) and at least one first outlet (14) for gaseous substances. ; 42) and at least one second outlet (9; 40) for the liquid substance. casing (6, 7, 8; 41), said casing being substantially At least one liquid inlet (11) surrounds the upper open space, and at least one liquid inlet (11) located at the top of the thing (6, 7, 8; 41), said inlet (11) is connected to the liquid (12 ), and the liquid is preferably transferred to the inner jacket of the casing (6, 7, 841). means for distributing onto at least a portion, preferably a major portion (7) of the ket surface; is arranged such that a movable liquid layer is formed on the jacket surface. Characteristic separation device. 7. Said casing preferably comprises a cylindrical or conical part (7), said part having The gas inlet is opened and the guiding means (1; 16) directs the inflow (4, 5) to the in a direction substantially tangential to the inner jacket surface of the casing part (7). according to claim 6, characterized in that it is arranged in the casing for guiding. separation device. 8. The main flow direction of the gas inlet is relative to the axis of symmetry (13) of said casing part (7). Said guide means (1; 16) are arranged such that the guide means (1; 16) are substantially perpendicular to each other, preferably Said casing part (7) has a substantially vertically extending axis of symmetry (13) and its connection 7. Separation device according to claim 6, characterized in that the fruit gas inlet is substantially horizontal. 9. The casing (6, 7; 41) has a guide rail for guiding the liquid film (12). 7. Separation device according to claim 6, characterized in that it is fitted with a roller (15) inside. . 10. Said guiding means (1) is a reactor fixed directly to said casing part (7). Separation device according to claim 6, characterized in that it consists of an outlet (1). 11. The temperature of the gas stream (4) leaving the separation device (2) is above 600 °C, preferably 8 The melt and/or A separation method for separating solid particles. 12. The gas stream (4) leaving the separation device (2) has at least one subsequent flow for gas cleaning. The gas (4) is then properly used as fuel. melt and/or solid particles from the gas stream according to claim 6, characterized in that Separation method to separate. 13. The gas stream (4) leaving the separator (2A) is introduced into the second separator (2B) melt and/or solid particles from the gas stream according to claim 6, characterized in that Separation method to separate.