DE3931900A1 - METHOD FOR BURNING GRANULAR RESIN MATCHES, ESPECIALLY ION EXCHANGERS - Google Patents

Description

The invention relates to a method for Combustion of bulk resin, in particular of ion exchangers.

The disposal of waste and garbage quantities is one Problem that has increased recently Attention is paid. Are basically Carbon-based wastes, such as in particular fine or granular synthetic resin waste, one Disposal accessible by incineration, however occur depending on the type of material and additional Content of other elements or additions, such as Water, considerable difficulty.

So are exhausted ion exchange masses, which as moist sludges are present as a result of extensive Use of such exchange resins for cleaning purposes available in considerable quantities. Your Besei However, it is not possible to do this easily on the one hand, the mud-like texture impedes is and on the other hand sticking together bake the masses in zones of higher temperatures occurs that are a hindrance to proceedings. Further mean the noticeable sulfur levels and pollution cleaning with metals, especially heavy metals, an additional obstacle.

The aim of the invention is therefore a method for Incineration of such waste without any problems can be carried out continuously and at where minimal emissions occur.

The invented for this purpose developed The process is characterized in that the Resin to burn with air in the lower Area of a fluidized bed with high temperature solid, non-abrasive, adsorptive granules, especially with clay, with spontaneous through blowing the mixture of the resin with the granules.

When blowing in, a melting or Baking of the resin material largely avoided be what by appropriate mixing effect when Blow into the granules in motion mixture is achieved. Spontaneously formed if necessary carburized agglomerates can, however, by the Painting effect of the mixture containing inert granules especially in a rotating fluidized bed trained lower furnace zone (as below specified) are ground again.

To avoid such agglomerates, a Mix resin and inert material in the oven be blown in, but then continuously inert or batchwise inert material can be removed got to.

Excess inert gas is preferably used in the furnace quantities of at least 2: 1 used, in particular a large excess of at least 5 times the amount. The inert material should in particular be finely divided be with a grain size of 1 mm maximum, the especially in the range from 100 to 400 µm, especially around 300 µm is selected.  

The inert material serves the one hand division of the resin material and temperature control tion as well as the inclusion of combustion pro products of inorganic type.

Temperature-controlling inert granules are known in fluidized bed technology, but sand or silica are generally used for this. It has now been found that the addition of excess fine-particle alumina (e.g. in spherical form commercially available as aluminum oxide for column chromatography; article no. 1076 from Merck, Darmstadt; the desired particle size is obtained by sieving) is particularly expedient in order to avoid sticking and baking and to absorb combustion components for which Al ₂ O ₃ in the form of alumina has an increased absorption capacity without a self-adhesive material being produced.

Preferably for the combustion of the granu laren material uses a device like she described in DE-PS 37 02 089 of the applicant ben is that a fluidized bed furnace for waste disposal shows a lower zone in the form of a Includes high particle density, in particular another as a rotating fluidized bed with an inclined ge floor is formed and one above located elongated zone of smaller particles dense and higher gas velocity than circulating layer works and in the bottom End additives are blown in.

In this known arrangement, a lower Solid outlet provided in the present  If not absolutely necessary, but still useful is moderate. The inclination of the floor to the bottom support of rotation and removal of inert Material or slag should be minimal be, with angles of inclination 30 °.

The combustion of cation exchangers will especially with significant oxygen over shot, with total lambda values 2 to get voted. Temperatures around 900 ° C are appropriate moderate.

When anion exchangers are burned, a sub-stoichiometric supply of oxygen (preference is given to working with lambda values from 0.5 to 0.8) to the lower zone of a two-zone bed, as stated above, reduces the nitrogen oxide emission, in which case the upper zone with excess air to achieve a complete burnout. The formation of thermal NO _x in this area can be avoided by temperatures below 1000 ° C.

As an additive, the bottom end in the top bed is blown in, lime appears to be useful Inclusion of the cation exchangers in considerable Amount of sulfur oxide present. The resulting finely divided calcium-containing calcium sulfate can at the same time as an absorber for inorganic traces serve in the combustion of loaded resin can arise.

The procedure according to the invention will be better understood from the following description with reference to the attached FIG. 1, which shows a fluidized bed furnace as specified in DE-PS 37 02 089:
An alumina / ion exchange mixture is blown into bed 1 (zone 1) via a mixing nozzle 2 and kept in rotation by means of 3 asymmetrically supplied air, as indicated by the arrows. In this way the residence of the resin in the lower zone is increased and a grinding effect is achieved which the baking masses which may occur break up again. At the upper end of this area, air is additionally blown in at 4 and the subsequent fluidized area 5 (zone 2) is extended and formed as a circulating fluidized bed with a separating cyclone 6 , extension tube 7 , via which the particulate solid is returned to bed 5 . Via 8 , additive, especially lime, is blown into the lower area of zone 5. Solid can be removed via 9 .

A modification of this furnace is shown in FIG. 2, in which material deposited in the cyclone 6 is returned to the lower zone 1.

Claims (10)

1. A process for the combustion of bulk synthetic resin, in particular ion exchangers, characterized in that the resin for combustion with air supply in the lower region of a fluidized bed with high-temperature-resistant, non-abrasive, adsorbent granules, in particular with alumina, with spontaneous mixing of the resin with the granules. 2. The method according to claim 1, characterized, that one with excess inert material, esp especially in a ratio of 2: 1, preferably the 5 times the amount works. 3. The method according to claim 1 or 2, characterized, that the particle size of the inert material is 1 mm, is chosen in particular around 100 to 400 microns. 4. The method according to any one of the preceding claims, characterized, that when burning cation exchangers with Excess oxygen, especially with a lambda Ratio of 2 is worked. 5. The method according to any one of the preceding claims, characterized, that the resin in the lower zone of a two-zone Fluidized bed is injected, the lower one stationary fluidized bed and an upper circulate of the bed.   6. The method according to claim 5, characterized, that when burning anion exchangers in the lower zones with substoichiometric Amounts of oxygen works, especially with lambda Values from 0.5 to 0.8. 7. The method according to claim 5, characterized, that the lower bed as a rotating fluidized bed is trained. 8. The method according to claim 7, characterized, that the rotating bed through a lower one inclined sieve bottom is limited. 9. The method according to any one of the preceding claims, characterized, that in the upper circulating fluidized bed of high gas velocity additives, in particular Lime for absorption of sulfur oxide, blown in will. 10. The method according to any one of the preceding claims, characterized, that work is carried out at temperatures around 900 ° C.