SE536161C2 - Reactor with resilient structure for gasification of gasification raw material - Google Patents

Description

15 20 25 30 35 535 '1B'l ceramic phases, which means that the oven step slowly but relentlessly increases in volume and size during operation. Therefore, there must be a sufficiently large expansion space between the inside of the reactor wall and the outside of the furnace shaft when the reactor is driven to avoid dangerously high mechanical loads arising in the reactor wall. Ceramic materials usually have a very high compressive strength, which is why an expanding ceramic liner can overload even a mechanically very strong reactor housing if the expansion is allowed to continue for a long time.

Gasification plants, intended for use for energy and chemical recovery in pulp mills, are expected to be in continuous operation for a very long time. Scheduled maintenance stops are made only once every 12-18 months in modern pulp and paper mills and are then carried out in 1-2 weeks. Unplanned stops in the gasification plant can therefore cause costly disruptions in the mill's energy and chemical recycling.

Prolonged downtime for repairs to the gasification plant or recycling system leads to significant production losses of pulp and paper. Therefore, very high demands are placed on the operational availability of such a plant.

Since a gasification plant produces large amounts of a hot and corrosive salt melt which then dissolves in water and forms an alkaline green liquor which is used in chemical recycling as well as large volumes of an energy-rich and combustible gas containing beneficial substances, high system safety requirements are placed in the carburettor plant.

Gasification reaction of black liquor from a pulp mill, can be schematically described with a chemical reaction funnel, see the formula below, where incoming black liquor, BL (aq), and oxygen, O2 (g), are mixed and reacted, actually burning in a partial combustion, in the carburetor whereby a salt melt, Me2A (1), and an energy-rich gas, Gdg) are formed, while heat is generated by the partial combustion. The formula below also indicates approximate molar amounts which are reacted in such a reaction at a temperature of about 1000 ° C. The formula shows that when one mole of B1 (aq) is gasified with 13 moles of oxygen, 2.7 moles of molten salt of the type composition Me2A (1) and 77 moles of different gaseous sleeves, here summarized Gx (g), are generated, while heat is generated. 1BL (aq) + 13o2 (g) _ »z fl MezAa) + 77Gx (g) + heat Through chemical analyzes the content of the constituent elements in black liquor can be determined.

The composition of black liquor BL (aq), also called thick liquor, from Swedish sulphate mills can well be described with a simple chemical formula, including with a normal for black liquor 10 15 20 25 30 35 536 'l6' | water content, see the formula below. Thick liquor from starch use has a considerably poor composition with, among other things, a significantly higher sulfur content in the black liquor. Pulp mills that take their wood raw material from areas close to the sea get elevated chloride levels in the black liquor.

BLÛ-CÛ: N fl ssKoscai.sH3s.sÛ22.3S1.sNo.icldl'19-5H2Ü The formed gas phase, Gx (g), contains a large number of different gaseous substances. The predominant substances in the gas phase are mainly the molecules H2, H2O, CO, CO2, H25, CH4 and N; but also small amounts of gaseous sodium and potassium compounds such as NaOH (g), NaCKg), KOH and KCl (g) are formed.

The salt melt formed, Me2A (1), comprises a mixture of positively and negatively charged ions. The melt can be described as a homogeneous ion melt which essentially comprises the ions Na fl KÄ C032] S2 ", Cl 'and OHI. 'which originates from the wood raw material but also from chemicals added to the pulp mill.

The salt melt is low viscosity down to a temperature of about 740 ° C as it solidifies to a substantially solid salt consisting of Na 2 CO 3 (s) and Na 2 S (s). Thereafter, a small residual volume of an alkaline salt melt remains with a significant content of Na + and OH 'and Cl' ions which first solidify at a temperature of about 400 ° C. The salt melt is very corrosive to metals already at a temperature of about 550 ° C. At a temperature above about 750 ° C, most metals corrode very quickly if they come in contact with the salt melt.

The steel in the reactor casing is of course not subjected to any appreciable corrosion or an impermissibly high temperature or to any high mechanical load from the ceramic casing of either local or general nature in addition to carefully determined strength nodes for the construction of the reactor.

In order to maintain a high level of operational reliability and achieve good energy recovery and to avoid disturbances in the chemical recovery and prevent damage to the ceramic liner or reactor casing, it is preferred that the gasification reaction takes place at an optimum temperature and with a suitably large oxygen supply. An excessively high reactor temperature makes the salt melt very corrosive to the ceramic lining, which shortens the service life of the lining. Too low a reactor temperature causes the gasification reaction to proceed slowly, the reactor has a negative heat balance and the gasification reaction stops completely and the salt melt solidifies. In addition, the molten salt is heavily contaminated with soot and poorly pyrolyzed black liquor during operation at too low a reactor temperature.

The melt thus solidifies at about 740 ° C, a temperature which is well within the ceramic requirement. This leads to another mechanism that causes volume growth. As the reactor cools, the volume of the melt and the ceramic lining decrease. The extra "crack volume" thus formed during cooling is filled with melt from the hotter inside of the ceramic lining by the capillary force. Gradually, in this way, more and more melt is sucked into cracks and joints in the lining until the melt finally solidifies. This phenomenon will over time lead to the ceramic lining growing in size and further diluting the volume increase that chemical reactions between melt and ceramic bring about and as described above. This intimal physical growth is specific to carburetors that gasify a feedstock at a temperature that significantly exceeds the melting temperature of the melt. In a comparison with so-called slag coal gasification (gasification above the melting point of the coal slag) the difference becomes clear. In such a carburettor, the gasification temperature is kept just above (approx. 50 ° C) the melting temperature of the coal slag. The slag will then solidify in the surface layer of the ceramic claim, which will therefore gradually swell and leave the surface via the so-called spalling. The ceramic material deeper in from the surface will remain basically unaffected by the coal slag. The described volume growth therefore does not take place in the same way as in gasification of black liquor where the solidification front of the melt is deep inside the material.

In order for the outer casing of steel of the reactor not to be exposed to too high a temperature and then to be damaged by corrosive substances in the gas phase or by the salt melt, an internal nuclear barrier is required which is resistant to the salt melt for a long time at a temperature of about 1000 ° C. partly a suitable thermal insulation inside the reactor to prevent the reactor housing from overheating but also to limit unnecessary heat losses through the reactor wall to the surroundings. As thermal insulation and as a chemical barrier inside the reactor, your different types of ceramic materials are usually used, but also other barrier materials in one or more layers and which in some cases also have specific properties of value for the construction as a whole.

When a reactor with an internal ceramic barrier is heated from room temperature to about 1000 ° C, a thermal expansion of the ceramic of about 0.8% takes place, while the outer horizontal reactor shell of steel expands much less about 0.25% because the temperature increase of the reactor shell is relatively small. about 200 ° C. The actual thermal expansion is, of course, dependent on the choice of material and the temperature profile in the reactor, but the values given are typical of most furnace structures. For a cylindrical reactor with a diameter of approx. 2 m and an expected dri fi temperature on the ceramic lining of approx. 1000 ° C, it is required at a first start of the reactor that there is a radial expansion space of at least 8 mm between the inside of the reactor housing and the outside of the ceramic barrier, and an axial expansion space correspondingly dependent on the height of the reactor to avoid contact between the steel reactor housing and the ceramic liner.

A number of mainly high-melting ceramic phases, mainly oxide-containing phases based on the elements Al, Cr, Ca, Mg, Si, and Zr such as, for example, α-Al 2 O 3, Cr 2 O 3, 3Al 2 O 3 ~ 2SiO ;, Na 2 O MgO, MgO-AlgO 2, CaO and ZrO 2 have been found to be relatively resistant or inert to the corrosive salt melt formed by black liquor gasification. Mixtures of two or more such ceramic phases containing α-AlgO 2, NagO-1 1 Al 2 O 3, Na 2 O 7 -Al 2 O 3, Na 2 O-MgO-5Al 2 O, MgAl 2 O 4 and MgO can also be used. A mixture consisting of α-AlzO; and fl your different types of so-called ß-alumina phases have also been tested where some of the Naïjons in the ß-alumina structure have been replaced by Lil ", KJ", Mg "and Cazf A prerequisite for good function both as a chemical and thermal barrier is however, that the ceramic phases are not prolonged to a temperature above about 1300 ° C in the presence of the salt melt.

A problem with the constituent ceramics is mainly the above-mentioned chemical and mechanical volume increase. In addition, the ceramic lining can react directly at high temperatures with alkaline substances present in the gas phase, which of course via diffusion easily penetrates deep into all open pores in the lining. These undesirable chemical reactions combined with built-up mechanical stresses caused by volume changes mean that the properties of the ceramic can be impaired in different ways so that the materials physically fall apart into smaller pieces.

As already mentioned, it is thus a very obvious problem that arises in reactions between the ceramic lining, the salt melt and the gas phase as many of these reactions lead to an increase in the proportion of solid phases in the lining, which in turn causes the ceramic to slowly increase in volume and the necessary the expansion space between the inside of the reactor vessel and the outside of the ceramic liner is slowly consumed, after which the reactor vessel can be exposed to a dangerously large mechanical load from an expanding liner.

It may seem easy to increase the expansion space between the expanding ceramic liner and the inside of the reactor vessel with wide open slots or a thick resilient ceramic atta mat so that the ceramic liner could be allowed to expand to a significant extent without being able to come into any dangerous contact with the reactor vessel walls. A wide gas gap or a thick porous atta bone night unfortunately has a very low thermal conductivity compared to a dense and corrosion-resistant ceramic lining. Typically, a porous ceramic har berrnatta has 1 / 50-1 / 100 of said thermal conductivity of said ceramic. Even a relatively thin fiber mat, which provides a certain but small expansion space, therefore results in a low temperature profile through the ceramic lining and a very steeply falling temperature profile through the mat.

Such a very unfavorable temperature distribution causes both an excessively high average temperature on the ceramic lining and a higher temperature on the inside of the ceramic lining towards the melt which sees an internal strongly radiant heat där where the black liquor droplets react with oxygen. This leads to faster chemical reactions between the salt melt and the ceramic lining and a faster expansion of the ceramic. In the worst case, the salt melt can penetrate the entire ceramic lining and reach out to the fiber mat, where it solidifies and thereby quickly destroys the necessary expansion space for the lining.

U.S. Pat. No. 3,528,647 describes an insulating structure between the steel shell and the lining of metallurgical furnaces. The structure consists of two components, an insulating component of a hard material closest to the lining and a stress-absorbing component of a soft material closest to the steel shell. The insulating component consists of silica with bound water and asbestos fibers. The seam with this component is to avoid heat transfer from the lining to the steel shell. The stress-absorbing component consists of a material that is resilient and capable of deformation, such as mineral wool or glass fibers. The publication teaches that it is desirable for the insulating material to have low thermal conductivity to minimize heat transfer. In metallurgical furnaces, however, the expansion takes place only by thermal expansion, while expansion in gasification plants also takes place by chemical reaction. Expansion by chemical reaction is much greater than the expansion that takes place through ordinary temperature increase in the stones, i.e. tennis expansion. Furthermore, belts are a very soft material which means that they do not offer a necessary and controlled resistance to chemical expansion. In addition, fiber blankets insulate too much, so the temperature gradient criterion is not met for the gasification plant.

US 6,725,787 describes a refractory container for gasification of black liquor. In the expansion gap between the metal shell of the container and the ceramic lining there is a crushable liner with a predetermined yield strength. Said liner, which consists of a crushable metal foam, provides a controlled resistance to expansion of the ceramic liner. However, after a number of starts and stops of the gasification plant, the ability of the metal foam to resist has been dried after the metal skin has been completely crushed.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to eliminate or at least minimize the above-mentioned problems, which is achieved in that a resilient structure with a resilient capacity is placed between an outer reactor housing and an inner refractory liner and that said resilient structure comprises at least a metal profile arranged to distribute the pressure load between said reactor housing and the inner refractory liner in that the metal profile or a number of metal profiles are positioned such that said metal profiles extend with the center line in the longitudinal direction of the reactor and substantially parallel to the intermediate gap zones, and that the cross-section of said metal profile or several metal profiles forms a circle or polygon.

Thanks to the invention as claimed in claim 1, a relatively constant counterforce is obtained on an expanding ceramic liner in a carburettor during operation within a large deformation range, without causing mechanical overload on the dryer reactor housing or on the liner inside the reactor.

Furthermore, thanks to the resilient ability of the compressible barrier, a counterforce is obtained which, in the case of a repeated thermal cycle of the start and stop type, when restarting the carburettor essentially retains its ability to generate a certain back pressure, which has the great advantage that when the ceramic liner is re expanded by thermal and chemical expansion, a relatively constant countercurrent fi is again obtained on the ceramic lining.

According to one aspect of the invention, said resilient structure is arranged to be compressed and deformed in the radial direction of the reactor shell with respect to its extent by at least 60% at a non-pressure of preferably not more than 2 MPa, more preferably in the range 0.5 - 1.5 MPa , that said resilient structure has a resilient capacity of preferably 2-4%, more preferably of 3-4% at pressure relief from operating pressure to atmospheric pressure, and that said resilient structure has a global porosity of at least 60%, preferably at least 80%, more preferably at least 90%. Due to the high global porosity of the resilient structure, it can be strongly deformed in the radial direction of the reactor housing to an extent of up to 70% 536 IU-1 while maintaining a suitably large thermal conductivity in the resilient structure. .

According to a further aspect of the invention, said structure comprises one or more hollow metal profiles, the cross-section of which has at least one line of symmetry which intersects through the center line one of the metal profile members. Thanks to this symmetry, the metal profiles can be strongly deformed without tipping over towards their profile neighbors, which can cause unwanted overlap between the profiles. A stable deformation in the radial direction of the reactor housing, on the other hand, gives an optimally large extent of deformation.

According to a further aspect of the invention, said metal profiles have at least one longitudinal line of symmetry. Thanks to this, straight metal profiles can be easily mounted all around into a cylindrical reactor vessel and uniformly cover substantially the entire inside of the cylindrical inner surface with profiles comprising a suitable distance between the profiles.

According to one aspect of the invention, the cross-sectional dimension of said resilient structure is more than 1.5% of the inner radii of the reactor wall and that said metal profiles are placed with such a selected distance x 'between the outer metal profiles that when the metal profiles are maximally defined / compressed the distance x between the respective metal profiles at least a few millimeters. Due to the fact that the metal profiles are deformed in a stable manner in the radial direction of the reactor housing, the maximum width of the profiles can be calculated when the profiles are maximally deformed, whereby the minimum allowable partition distance between the profiles can be easily calculated without risking overlap or sheet metal cracking.

According to yet another aspect of the invention, said metal profiles have mirror-symmetrical cross-sections with the mirror plane passing through the profile center and the center line and directed substantially perpendicular to the tangential direction of the reactor housing. Thanks to the mirror symmetry of the profile and the direction perpendicular to the reactor housing, a stable deformation is obtained during the entire deformation process without risk of overturning the metal profile.

According to another aspect of the invention, a barrier material with such good thermal insulation is placed between said ceramic liner and said resilient structure so that the metal profiles in the resilient structure do not become hotter than about 400 ° C during normal operation of the reactor. Thanks to an extra thermal insulation, any residual melt is prevented from reaching the metal profiles and causing corrosion on them.

As the residual melt solidifies at 400 ° C, it can therefore not reach the metal profile.

According to a further aspect of the invention, a porous ceramic felt is placed between and inside the metal profiles which fills the free volume in and between the metal profiles and thereby reduces the heat transport through the resilient structure due to both reduced gas convection and reduced heat radiation. Thanks to the ceramic salt, the total heat dissipation to the wall of the reactor vessel can be limited.

According to another aspect of the invention, a portion of the metal coils are arranged with the center lines perpendicular to the center line of the reactor housing between the inside of the reactor housing and the core liner in the form of spirals or concentric divisible rings and the remaining part of the inside is covered centerline so that together they enclose the entire inside of the reactor housing. Due to the fact that the metal coils can be formed relatively easily into spirals or rings, whole or divisible, the reactor top, which usually has a dome shape for reasons of strength, can be relatively easily covered by metal spirals or concentric profile rings. In the same way, the reactor outlet, which is usually confomiat, can also be covered by concentric rings or spirals.

According to yet another aspect of the invention, said gasification raw material comprises liquids obtained in pulp production such as black liquor or salt thick liquor. These liquids are energy-rich and provide good operating economy as well as a relatively high energy yield.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail below with reference to the accompanying drawings, in which: Fig. 1 shows a sector, with a circumference of about one sixth of a radial cross-section, through the center of a gasification reactor, Fig. 2 shows cross-sections of some different types of pipe profiles, Fig. 3 shows the design according to fig. 1 on a slightly larger scale, Fig. 4 shows the back pressure, P (MPa), against a reactor shell as a function of deformation / compression of a resilient structure when said structure is deformed between a ceramic liner and the inside of a reactor wall; and 10 15 20 25 30 35 536 '1B'l 10 Fig. 5 shows result curves from tests of a pipe profile of the ferritic high-strength steel Doga18OODP where the profile has undergone a number of pressure / relief cycles.

DETAILED DESCRIPTION OF FIGURES For a detailed description of a possible, possible construction of a carburettor reactor according to the invention, reference is made to gasification reactors developed by Chemrec AB.

Other designs and constructions of the carburettor container are also conceivable without thereby deviating from the scope of the invention. It is preferred, however, that the gasification reactions take place at such a high temperature that the salt content of the lye forms a melt which is handled at a temperature considerably (> 100 ° C) above the melting point of the salts in order to obtain the benefits according to the invention.

Fig. 1 shows a sector, with a circumference of about one sixth of a radial cross-section 15, through the center of a cylindrically designed gasification reactor 100. Said reactor 100 is intended for gasification of gasification raw materials, preferably effluents obtained in pulp production, which gasification organic raw materials and inorganic compounds, wherein said compounds when gasified in the presence of oxygen and / or air at a gasification temperature where the melting temperatures of the constituent inorganic compounds are at least 100 ° C lower than the gasification temperature, are converted to a hot reducing gas above 950 ° C but below 1300 ° C and comprising CO, CO 2, H 2 and H 2 O and a salt melt; said reactor comprises an outer reactor housing 7 with a center line C, which center line C coincides with the center line of the reactor 100, and an inner refractory ceramic liner 2, 3, 4, which is preferably built up of one or more ceramic layers, wherein between said reactor housing 7 and said liner 2, 3, 4 is again a resilient structure 5 with a resilient feature and wherein said resilient structure comprises at least one metal profile 12 arranged to distribute the pressure load between said reactor housing 7 and the inner refractory liner 2, 3, 4 by the metal profile 12 or a number of metal profiles 12 are positioned in such a way that they form parallel pressure-absorbing bridges with intermediate gap zones 22.

By gasification temperature is meant the global temperature out of the reactor 100, i.e. which can be considered to correspond to the average temperature that the gas 9 and the melt 1 have when they leave the reactor 100. The reaction temperature inside the reactor 100 is in some zones considerably higher. Said resilient structure 5 is in a preferred embodiment arranged in an expansion space 6, which space 6 in turn is arranged between said reactor housing 7 and said liner 2, 3, 4. The resilient structure 5 can be deformed / compressed when subjected to pressure and then partially resilient during pressure relief. The expansion space 6 can preferably be provided on its inner surfaces with a barrier material 13, 14, between which the resilient structure 5 is arranged.

The barrier material 13, 14 may preferably comprise one or more layers. Figure 1 also shows the radial direction 15 of the reactor housing and that the releasable structure 5 has a thickness y extending in the radial direction of the reactor housing 15.

Between said lining 2, 3, 4 and approximate resilient structure 5 it may be preferred that a barrier material 13 with such good thermal insulation is placed that said metal profiles 12 in the resilient structure 5 do not become hotter than about 400 ° C during normal operation of reactor.

In certain embodiments according to the invention, it may also be preferred that a barrier material 14 is located between the inside of the reactor housing 7 and the resilient structure 5 so that the reactor housing 7 is not exposed to high temperatures.

For the physical stability of the ceramic liner 2, 3, 4 in the case of a repeated thermal cycle, of the type start and stop, it is a very desirable advantage if the ceramic blocks of which the liner is built up can constantly have a certain inwardly directed support pressure of the reactor housing. via the resilient and partially resilient structure 5.

Said resilient resilient structure 5 can reclaim formed gaps between the ceramic liner 2, 3, 4 and the reactor casing 7, but also minimize the occurrence of open shrinkage cracks 10 or gaps that occur in joints 11 between the various ceramic blocks included in the liner 2, 3, 4. reactor.

In order to prevent overtemperatures on the reactor casing 7, it may be preferable for said reactor casing 7 to be cooled to dissipate the heat from the reactor casing 7 to the surrounding cooling medium, usually air 8. Temperatures of about 300 ° C for pressure vessel steel are permissible in order to meet normal strength standards. without the wall thickness of the reactor having to make too large.

Said resilient structure 5 preferably comprises one or more thin-walled profiles 12 preferably made of metal. Fig. 1 shows metal profiles 12 which have a cross section corresponding to a regular hexagon. The metal profiles 12 in turn are constituted by long tubes placed substantially parallel to the center line C of the reactor housing 7, i.e. in the longitudinal direction of the reactor 100. The center line 21 in the pipe profiles 12 extends substantially perpendicular to the radial direction of the reactor housing 15 and the metal profiles, also called pipe profiles, 12 are placed with such a selected distance between their respective center lines 21 that a distance x '(see Figure 4) is obtained between two adjacent metal profiles 12. outside. When the metal profiles 12 are maximally deformed / compressed, the distance x 'has decreased to x (see figure 4) between the outer sides of the respective metal profiles (12) and where x is greater than zero, preferably one millimeter or possibly slightly larger.

Fig. 2 shows cross-sections for a number of different types of metal profiles 12-a to 12-k. It is preferred that said structure 5 comprises one or more hollow metal profiles preferably with closed profile, the cross section of which has at least one line of symmetry S which intersects through the center line 21 of the metal profile (s) 12 and where the extension of the oxygen line S intersects through the center line C of the reactor shell 7.

For each cross section, the line of symmetry S is displayed in the form of a dashed line. The pipe profile or metal profile is preferably positioned so that the line of symmetry S of the cross section is parallel to the radial direction 15 of the reactor housing, while the center line 21 of the pipe profile runs substantially perpendicular to said radial direction 15 of the reactor housing, which means

As shown in Fig. 2, the cross sections of the metal profiles 12 may have different shapes, for example the cross sections may be of different types of polygons, while in some embodiments it may be preferred that the resilient structure 5 comprises a number of circularly shaped metal profiles 12. -e, 12-h. In one embodiment, said releasable structure 5 may preferably comprise a number of hexagonally shaped metal profiles 12-a which extend with the center line 21 of the hexagon directed substantially parallel to the center line C of the reactor housing 7.

In a further embodiment, said resilient structure 5 comprises a number of elliptically shaped metal profiles 12-c, which extend with the major axis of the ellipse in the cross section directed substantially parallel to the radial direction 15 of the reactor housing 7.

In other embodiments, a number of pentagonally shaped metal profiles 12-g, which extend similarly with the line of symmetry of the pentagon in the cross section directed substantially parallel to the radial direction 15 of the reactor shell 7, may be more preferred.

An alternative to a pentagonal shape may be an octahedral shape 12-d.

Common to said metal profiles 12 is that they have at least one mirror symmetrical cross section where the mirror plane coincides with the center line 21 and where the line of symmetry S is directed substantially parallel to the radial direction 15 of the reactor housing 7, i.e. in such a way that S is directed to intersect the center line C.

Projects according to the various embodiments described above allow a significant plastic deformation at a certain reached moderate load level and then give a relatively constant deformation resistance within a large defining area. Furthermore, this type of removable structures has a heat conduction suitable for the furnace construction, the ceramic lining.

The pipe problems according to the invention are preferably made of steel grades commonly used on the market suitable for the environment which is characteristic of the invention. The pipes with the selected profile are placed in the axial direction of the reactor and manufactured in lengths that are adapted to the extent of the reactor in the axial direction. The pipe length can preferably be adapted to reach the entire axial length along the reactor, but the pipe lengths can also be shorter depending on mounting technology and due to the occurrence of penetrations through the reactor wall 7, which makes it necessary to divide the pipes into parts.

In some embodiments according to the invention, a part of the metal profiles 12 arranged with the center lines 21 perpendicular to the center line C of the reactor housing 7 between the inside of the reactor housing 7 and the ceramic liner 2, 3, 4, preferably in the form of spirals or concentric rings and the remaining part of the inside metal profiles 12 where the center lines (21) are arranged substantially parallel to the center line C of the reactor housing 7 so that they together enclose the entire inside 7 of the reactor housing.

All profiles shown in Fig. 2 have at least one mirror plane through the profile. It can be an advantage to place the problems so that the mirror plane is substantially perpendicular to the pressure vessel wall and parallel to the radial direction 15 of the reactor vessel as well as parallel to the center line 21 of the sample the ceramic lining 2, 3, 4. The tube profiles 12-f, -g, -h can be produced by folding elongate plates into desired profiles 12, after which the plate edges 20 are welded together. 15 The profile 12-i is composed of the profile 12-a and 12-j which are stacked on top of each other and then welded together at the waist 20. A type 12-i profile has almost twice the deformation capacity compared to profile 12-a without requiring a slightly larger CC distance between the profiles than profile 12-a in the resilient structure 5. The profile 12-k is made up of a number of elliptical tubes of type 12-c which are welded 18 to a plate 19 and form a panel. Such panels can then be placed in the reactor vessel and welded together there to a coherent resilient structure 5 with the pipe profiles 12 directed towards the reactor housing 7 and with the plate 19 directed towards the ceramic lining.

Fig. 3 shows an original structure 5 where the panel comprises a number of hexagonal tubes 12-a. It is understood that tubes also with other cross-sectional profiles, for example cylindrical 12-e, pentagonal 12-g, can be used in the same way to build up the panel. When such a resilient structure 5 consisting of pipe profiles welded to a plate is compacted by an expanding liner, this preferably leads to the plate 19 being stretched, which can provide an extra abutment crane against the liner without the pressure load on the reactor vessel 7 necessarily increasing.

Fig. 3 also shows an embodiment according to the invention where between and in the metal profiles 12 a ceramic film 16, 17 is placed which fills the free volume between the metal profiles 12 as well as inside the metal profiles 12 and thereby reduces the heat transport through the exposed structure 5 due to both reduced gas convection and reduced friend radiation.

For the permissible structure 5, a global fill factor e can be calculated. The volume ratio can be calculated with the aid of Fig. 3 according to, VMe / Vm height = 2R \ / O, 75 and L the length of the profile and the wall thickness of the profile as well as the division distance of the profiles, C- C distance = 3R which means an initial distance between the profiles corresponding to R. With the input measured value t / R = 0.0571, e = 0.066. This means that the structure 5, when made up of hexagonal profiles 12-a, contains only 6.6% dense material and 93.4% global porosity.

It is understood that the reactor wall shown in Figure 3 actually has a, overall, curved shape as shown in Fig. 1. The section shown in Figure 3 forms such a small part of the entire reactor wall that the wall is shown as a plan for simplicity. wall in 3 gur 3.

Fig. 4 shows the back pressure, P (MPa) against the reactor housing 7 as a function of defining / compression of the thin-walled pipe profiles 12 when they are deformed / compressed between the ceramic liner 2, 3, 4 and the inside of the reactor housing 7. Within a deposition range from 0% to about 6%, an elastic deposition takes place first, then a plastic deformation takes place up to about 70% with a relatively constant back pressure. Thereafter, the tube walls 12 are pressed against each other, after which the back pressure rises rapidly and the expansion space is consumed.

Said releasable structure 5 is arranged to be compressed and deformed in the radial direction 15 of the reactor housing 7 with respect to its extent (y) by at least 60% at a standard thickness of preferably at most 2 MPa, more preferably 0.5-1.5 MPa.

It is further preferred that said resilient structure has a resilient capacity of preferably 2-4%, more preferably 3-4% when the structure is depressurized from driving pressure to atmospheric pressure and a global porosity of at least 60%, preferably at least 80%, more preferably at least 90%.

By measuring the deformation force and the deformation of long cut cut parts of the pipe sections 12 suitable for the measurement, and taking into account that the sections 12 are distributed with an even CC distance (ie the distance between a pipe section centerline 21 to the nearest pipe profile corresponding centerline 21) in the resilient structure 5, the average pressure against the reactor shell can be calculated. Since the pipe profiles have a thin wall relative to the reactor casing and are preferably regularly distributed with a constant C-C distance around the entire reactor casing, the load on the reactor casing from the probes 12 can be considered as a uniform internal pressure which is relatively small iron with the maximum design pressure.

In accordance with what has been previously mentioned, the metal profiles 12 are suitably arranged with such a selected distance between their respective center lines 21 that a distance x '(see Figure 4) is obtained between the outer sides of two adjacent metal profiles 12. In a preferred embodiment, x 'is preferably approximately equal to R according to the calculation above.

Fig. 5 shows results from compression tests performed by means of a thermal gradient set of a metal profile of a ferritic high-strength steel called Dogal800DP. The x-axis shows the percentage deformation of the profile as a function of the y-axis load per mm (kN / mm) of bearing surface of the steel pipe. Temperature was adjusted before each test to obtain the same temperature on the two plant surfaces that are calculated to prevail for the entire refractory solution. The temperature of the sample can therefore be assumed to have the same temperature gradient as if it had been placed in a carburettor according to the invention. 16 15 A number of relief cycles were performed at regular intervals for each of the tests.

From the curves it can be deduced that tests of similar samples generate similar results.

In general, the mechanical test results confirm the results from the simulations, both in terms of the shape of the curves and the magnitude of the load.

The hot salt melt formed during the gasification runs partly on the surface of the ceramic liner 2 and can penetrate into the hotter part of the liner 2, 3 and there form new solid ceramic substances when it reacts with the ceramic material. This causes the lining to have a larger volume than it originally had during assembly. Such volume-increasing reactions cause the hot part of the liner 2, 3 to slowly but relentlessly increase in volume and size during normal operation of the reactor. Ceramic materials generally have a high compressive strength, so an expanding ceramic liner of normal thickness can easily overload even a mechanically strong reactor housing 7 if the reaction is allowed to continue for a long time and if there is no suitable expansion space for the ceramic lining inside the reactor. Therefore, during prolonged operation of the reactor, there is preferably a sufficiently large energy structure 5 between the inside of the reactor casing 7 and the outside of the ceramic liner 4 to prevent dangerously high mechanical loads from arising in the steel reactor casing 7. High pressure loads inside the ceramic liner 2 can also in itself cause parts of the liner 2 to crack loose from the inside and be lost through so-called spalling, whereby the service life of the liner deteriorates due to reduced material thickness. In the worst case, large internal sputtering can also cause an internal race to arise from the lining, which can quickly lead to a dangerous local overheating of the reactor wall 7 in areas where the ceramic lining has been lost. The damage can be particularly extensive in a dome-shaped reactor roof where the lining needs some support from its neighbors to maintain the stability of the roof.

To prevent the salt melt from penetrating the ceramic liner and possibly reaching the surface structure 5 and damaging the reactor wall, it is preferred that the temperature of the salt melt be so low that the salt melt solidifies into a substantially solid salt inside the colder parts 3, 4 of the ceramic liner. as already mentioned at a temperature of about 740 ° C while a small volume fraction of the melt is enriched in impurities such as NaCl and NaOH causing the whole melt to solidify first at about 400 ° C. In general, however, it can be said that chemical reactions between the salt melt and a high-melting ceramic liner are rather slow at temperatures below about 600 ° C. The thickness of the various ceramic liners and the ductility of the materials are preferably selected in such a way that the inside 2 of the barrier is so hot that the salt melt is substantially always free-flowing and easily flows out of the reactor at normal operating temperature while the colder part of the ceramic lining 4 causes the salt melt to solidify completely. Thereby, the melt can be prevented from penetrating cracks and pores deep into the outer parts of the liner and in the worst case reaching the reactor wall.

The choice of material for the innermost ceramic lining / barrier is mainly governed by the fact that the materials must have good chemical resistance to an alkaline melt and should therefore have a high melting temperature. In some parts of the reactor, the melt may occasionally have a temperature above 1050 ° C. Suitable ceramic materials are chemically resistant to an alkaline melt and have no or very little open porosity. Furthermore, it is preferred if they are relatively resistant to rapid temperature changes. Such materials are unfortunately relatively good heat conductors.

The combination of the thickness, chemical resistance and thermomechanical properties of the various refractory ceramic liners / barriers as well as the tinic conductivity of the materials may preferably need to be adjusted in such a way that the melt is substantially free-flowing on the inside of the innermost ceramic liner. at about 1000 ° C so that the salt melt 1 that is formed is not contaminated by soot from incompletely reacted black liquor.

The underlying ceramic barrier materials 3, 4, 13 are preferably chosen so that the thermal conductivity of these ceramic linings / barriers becomes considerably lower than that of the innermost ceramic lining 2. It is suitable that these intermediate ceramic materials have a thermal conductivity which is 1 / 3-1 / 10 of what the innermost ceramic lining 2 has, partly to reduce the heat losses through the barriers and partly to prevent the melt from reaching the resilient structure 5. Since the intermediate core linings / barriers 3, 4, 13 have a lower working temperature and in addition avoid the effect of a by-passing salt melt, the corrosion requirements on these materials are reduced, but they must be able to withstand very long-term chemical attacks by the melt which penetrates relatively deep into the ceramic barrier. It may be preferred that the intermediate ceramic barriers, 3, 4 at long contact time with the salt melt do not expand significantly so that the expansion space in the structure 5 is not consumed.

The invention also relates to a method for manufacturing and arranging a resilient structure S between a reactor housing 7 and an inner refractory liner 2, 3, 4 in a gasification reactor where said resilient structure 5 comprises hollow metal profile 12, which is placed on a cc distance corresponding to 0.3-0.7 of the circumference of said hole profile 12, preferably 0.4-O6 of said circumference. Said profile / s 12 are fixed on a sheet metal sweep 19, preferably with approximately the same sheet thickness as said profile / s 12, whereby a section of profiles on a sheet metal sheet 19 is formed, which are joined, preferably welded together. , to a coherent resilient structure 5, the prosthetic side of the sections being directed towards the reactor housing 7.

Said sections 19 are trimmed to the correct radius of curvature for said reactor before joining.

A number of said profiles 12 are fixed in parallel, centered with a longitudinal weld seam 18, with the center line 21 of the problems extending substantially parallel to the vertical center line C of the reactor.

The invention is not limited by what has been described above, but can be varied within the scope of the appended claims. It will be appreciated, for example, that the reactor of the invention is well suited for the gasification of various types of liquors from chemical and semi-chemical pulp mills such as black liquor and various types of sulfur liquors, for example Na- or K-based sulphite liquors.

Furthermore, it is understood that the invention is applicable to the gasification of many other different types of organic materials and waste, for example household waste. The invention is particularly applicable to dry gas raw materials which include salts which in the dry gas reactor must be kept at a temperature well above (> 100 ° C) the melting point (melting temperature) of the salts, which in turn leads to the melt penetrating far into the ceramic requirement 2,3,4 before it solidifies.

Of course, it is also possible to mix different types of liquors within wide limits and gasify the mixture in the inventive reactor. It is also possible in connection with the dry gasification to mix a small amount of incoming dust into the effluent, for example electric dust from recovery boilers, which dust contains relatively low-melting compounds such as Na2CÛ3 OC-ll N32SÛ4.

It is also conceivable for the person skilled in the art to place within the scope of the invention not only one but two or more rows of metal profiles next to each other seen in the radial direction of the reactor in order to obtain the advantages according to the invention. Furthermore, in some embodiments it may be preferable to arrange the metal profile in a spiral around most of the internal refractory lining. Such a helically resilient structure would, among other things, 536 'H31 make the difference that the longitudinal development of the metal profile contributes to the counter-changing force.

Claims (13)

l5 20 25 30 35 536 161 20 PATENT REQUIREMENTS 1. A gasification gasification reactor, arranged to handle gasification raw materials comprising organic and inorganic compounds, said compounds for gasification in the presence of oxygen and / or air at a gasification temperature where the melting temperatures of the constituent inorganic compounds are at least 100 ° C lower than the gasification temperature, is converted to a hot reducing gas above 950 ° C but below 1300 ° C and comprising CO, CO 2, H 2 and H 2 O (g) and a salt melt; said reactor (100) comprising an outer reactor housing (7) and an inner refractory liner (2, 3, 4) wherein a resilient structure (5) having a resilient capacity is located between said outer reactor housing (7) and said inner refractory liner (2, 3, 4), characterized in that said releasable structure comprises at least one metal profile (12) arranged to distribute the pressure load between said reactor housing (7) and the inner refractory liner (2, 3, 4) by the metal profile (12) or a number of metal profiles (12) are positioned so that said metal profiles (12) extend with the center line (21) in the longitudinal direction of the reactor and substantially parallel to the center line (C) of the reactor housing (7) and form parallel pressure absorbing bridges with intermediate gap zones ( 22), and that the cross section of said metal profile or number of metal profiles (12) forms a circle or polygon. Reactor according to Claim 1, characterized in that in that said resilient structure (5) is arranged to be compressed and deformed in the radial direction (15) of the reactor housing (7) by at least 60% at a normal pressure of preferably not more than 2 MPa, more preferably in the range 0.5 - 1.5 MPa. Reactor according to claim 1 or 2, characterized in that said resilient structure (5) has a rebounding capacity of preferably 2-5%, more preferably of 3-4% at pressure relief from drain pressure to atmospheric pressure. Reactor according to any one of the preceding claims, characterized in that said resilient structure (5) has a global porosity of at least 60%, preferably at least 80%, more preferably at least 90% Reactor according to any one of the preceding claims, characterized in that said structure (5) comprises one or more hollow metal profiles, the cross section of which has at least one line of symmetry (S) whose extension intersects the center line (C) of the reactor housing (7). 10 15 20 25 30 35 536 'l6'l 21 Reactor according to any one of the preceding claims, characterized in that said metal profiles (12) are arranged with such a selected distance (x ') between the outer sides of the respective metal profiles (12) that when the metal profiles (12) are maximally defined / compressed, the distance (x ) between the respective metal profiles (l2) greater than zero. Reactor according to any one of the preceding claims, characterized in that a barrier material (13) with such good thermal insulation is placed between said liner (2, 3, 4) and said resilient structure (5) that the metal profiles (12) in the the resilient structure (5) does not become hotter than about 400 ° C during normal operation of the reactor. Reactor according to one of the preceding claims, characterized in that a porous ceramic film (16, 17) is placed between and inside the metal profiles (12) which fills the free volume in and between the metal profiles (12) and thereby reduces the heat transport through the resilient the structure (5) due to both reduced gas convection and reduced heat radiation. Reactor according to one of the preceding claims, characterized in that a part of the metal profiles (12) is arranged with the center lines (21) perpendicular to the center line (C) of the reactor housing (7) between the inside of the reactor housing (7) and the refractory liner (2, 3). , 4) in the form of spirals and the remaining part of the inside is covered by metal profiles (12) where the center lines (21) are arranged substantially parallel to the center line (C) of the reactor housing (7) so that together they enclose the entire inside (7) of the reactor housing. Reactor according to claim 1, characterized in that said gasification raw material comprises liquids obtained in pulp production such as black liquor or salt thick liquor. A method of manufacturing and arranging a resilient structure (5) between a reactor housing (7) and an internal refractory liner (2, 3, 4) in a gasification reactor, characterized in that said resilient structure (5) comprises hollow metal profile (s) (12), said profile (s) (12) is fixed on a sheet metal sweep (19), preferably with approximately the same sheet metal thickness as said profile (s) (12), whereby a section of profiles on a sheet metal sweep (19) is formed. , which are joined, preferably welded together, to a coherent resilient structure (5), the profile side of the sections being directed towards the reactor housing (7), the metal profiles (12) being placed at such a selected distance 535 '166' 22, between their respective center lines (21) that a distance (x ') is obtained between the outer surfaces of two adjacent metal profiles (12). Method according to claim 1 I, characterized in that said sections (19) are joined to the correct radius of curvature of said reactor before joining. Method according to claim 11, characterized in that a plurality of said profiles (12) are fixed in parallel, centered with a longitudinal weld seam (18), with the center line (21) of the profiles extending substantially parallel to the vertical center line (C) of the reactor.