DD239219A1 - METHOD FOR OBTAINING SECONDARY RAW MATERIALS FROM FIXED BED GASES - Google Patents

Abstract

The invention relates to the field of coal upgrading, especially to fixed bed pressure gasification. The aim and object of the invention is to use the ashes and slags produced in large quantities as secondary raw material and at the same time to find a more favorable mode of operation of the generators and their ash removal. The essence of the invention is that it is fed from the generators ashes via a suitable continuously operated conveyor in their natural Koernung a central processing plant and yet arbitrary grain fractions can be obtained. The solution is particularly applicable following the process for solid bed pressure gasification of lignite.

Description

For this 1 page drawing

Field of application of the invention

The invention relates to the field of fixed bed pressure gasification, in particular to the discharged from this process ashes.

Characteristic of the known technical solutions

The ash residue obtained in the fixed bed pressure gas generators passes through a dropping chamber and a scraper chain conveyor circulating in the water bath into a hydraulic conveying system consisting of slag breaker, flushing channel, ash slurry pump and ash brine line. This process is currently in progress. operated on an industrial scale. To increase the performance of the fixed-bed pressure gas generators, an operating mode with temperatures close to the slag limit of the ash is desired, with some of the ash already sintering together to form coarse slag. This causes frequent blockages in the ash processing line.

To avoid this condition, a solution according to DD-WP 201457 is known, in which a device is described in which the retention of coarse slag pieces in front of the ash slurry pump by placing an inclined solid grate and a bucket elevator in the pump inlet shaft is made.

A disadvantage of this proposed solution is the use of the bucket elevator described, which tends to wear damage in the case of abrasive ash for a short time. On the other hand, it is not excluded that the arranged in the ash stream solid rust is offset after a short period of operation.

Another method is described in DD-WP 2636197, in which can be achieved by speed adjustable ash scraper chain conveyor analogous to the amount of ash accumulating a nearly uniform ash flow. With the mentioned method, however, the problem of increased slag accumulation and ash utilization has not been solved. To improve the ash movement in the generator and to increase the lifespan of the conical closures DD-WP 157105 a slag breaker is described in the generator.

Due to the coarse refraction of the slag in the generator, however, blockages may also occur in the hydraulic discharge system. Ash removal is virtually eliminated by the proposed crushing process. A treatment of the resulting slag and ash as a secondary raw material has not been done, has not been found in the literature. So far, the ashes were only deposited in landfills. A thorough investigation of the properties of the ashes has not been done.

Object of the invention

The aim of the invention is the winning of secondary raw materials from the ashes of the fixed bed pressure gasification with simultaneous establishment of a trouble ash removal from the generators.

Explanation of the essence of the invention

The invention has for its object to be able to win defined ash fractions by finding a suitable technical solution and at the same time be able to set up by a new design of ash transport from the generators a hotter driving style of these generators.

According to the invention, the object of the invention is achieved in that the resulting from the individual pressure gas generators ash is fed via a central, continuously operating conveyor in their natural grain of a central processing device in which the Gesamtaschestrom is processed to the effect that by suitable classification and crushing and their meaningful combination any ash fractions between 4mm and greater 100mm generated and sustained, with a maximum particle size of less than 16 mm, preferably less than 4 mm is used for hydraulic removal in landfills. In addition, it is possible to recover the fraction usable as secondary raw material smaller than 4 mm after passing through a slurry stage from the ash-water mixture. To ensure a high quality of the ash fractions obtained, according to the invention, the adhering fine ash constituents are to be removed from the grain fractions during passage through the water by the sieves. The rinsing of the fine fraction less than 4mm is carried out in such a way that the collection of eligible ash fraction and mixing with motive water is carried out via a water level control in an inlet trough, that primarily by one to two pump inlet shafts, the supply to the ash slurry pumps, wherein in the sump the shafts to increase the eligibility of the ash-water mixture or for producing a homogeneous mixture additionally water is injected. By measuring the quantity of the incoming ash and the branched off for recycling and by a quantitative amount of water in the correction or driving water, a constant charge ratio ash / water can be adjusted. With the regulation of the loading ratio and maintaining the ash particle size greater than 4mm from the ash-processing line, there is a blockage-free discharge of the ash in the ash-removal line with simultaneously reduced wear on the machine elements and an increased delivery rate of the system. The advantages of the above solution are in addition to the importance of secondary raw material extraction in a continuously operated and thus trouble-free ash removal port of the generators and in the given with this solution possibility to operate the generators hotter, d. H. larger slag boulders pass through the transport system without causing any interference.

embodiment

The detailed explanation of the invention will be made with reference to the embodiment shown schematically in the accompanying figure. The total ash flow passes through the conveyor belt 1 in the sieve classifier 2. Here takes place under. Supply of rinsing water 3, the separation of the ash in the grain fraction smaller than 4mm, 4-16 mm and larger 16 mm. The fraction less than 4 mm, which is mixed with rinsing water, can optionally be moved directly into the rinsing channel 8 or via a mechanical classifying trough 16 into the loading 15, wherein the finest ash components from the slurry are also conducted into the rinsing channel 8. For the fractions 4-16mm two conveying paths are possible, the former leads to loading 14 and the second via the crusher 4, which breaks the good in the fraction less than 4mm, either in the flushing channel 8 or 15 for loading.

Finally, the fraction greater than 16 mm is generally broken in the crusher 5 to the particle size <16 mm and separated in the adjoining sieve classifier 6 with the aid of rinsing water 7 into particle sizes of 4-16 mm and less than 4 mm. While the fraction 4-16mm is fed to the middle Brechstufenauslauf from the Siebkassierer 2 for further processing already described, the fraction less than 4mm in the flushing channel 8 or in the loading 15 can be driven. The introduced into the flushing channel 8 ash fraction smaller than 4 mm is conveyed with propellant water 9 in the respective pump inlet shaft 10.

The introduced by means of rinse water additional water 11 loosens the water-ash mixture in the inlet shaft 10 so that it as a homogenized mixture to the ash slurry pump 12 tapers.

By quantitatively determining the total ash flow at position 19 and the partial ash streams of the fractions less than 4 mm and 4 to 16 mm at positions 18 and 17, taking into account the amounts of water 3, 7, 9 and 11 introduced, a constant predetermined loading ratio of water / ash, z. B.: 20/1 in the ash clearing line 13 drove. If a quantity of ash caused by the pump is exceeded, a second pump system can be started up in parallel automatically. For a more detailed description, a generator plant of the coal-pressure gasification plant with 15 generators, in which 300 tons of coal with an ash content of 10% are used every hour, is ash-averaged.

The total ash amount is 21 t / h, which is fed to the ash processing plant.

In the classifier 2 5 t / h granules are held in the fraction 4-16 mm and the loading 14 fed. The amount of 8,5t coarse fraction larger than 16 mm fraction is broken in crusher 5 to less than 16 mm and fed to the classifier 6. Here a further 7t / h coarse ash fraction of 4-16mm were endured and promoted for loading 14. From the sieve fraction less than 4 mm of the classifier 2, which is obtained in a total amount of 9t / h, 16 8t / h fine slag of the fraction 0.2 to 4mm recovered for recovery and fed to the loading 15 by mechanical Klassiertrog. The remainder of less than 0.2 mm gets into the hydraulic rinse.

Claims (5)

Invention claim: 1. A process for the production of secondary raw materials from Festbettdruckvergasungsaschen and for easy ash removal from the compressed gas generators and thus possible hot driving this gas generators, characterized in that the total ash flow is supplied by a suitable, continuously operating central conveyor of the compressed gas generators of a central processing plant and in this suitable classifiers in different fractions, preferably in three fractions, is broken down, wherein the granular components of the ash> 4 mm are recovered from the ash stream as secondary raw material, the coarse ash constituents, preferably> 16mm, crushing devices fed and crushed, preferably to a grain size $ 16 mm, and for hydraulic transport in landfills only ash fractions <16 mm, preferably <4 mm, come into question. 2. The method according to item 1, characterized in that the granular components of the ash of the fraction 0-4mm are additionally obtained by a mechanical Aufschwemmeinrichtung as secondary raw material. 3. The method according to item 1 and 2, characterized in that the total ash optionally flushed or can be obtained as a defined ash fraction as a secondary raw material. 4. The method according to item 1-3, characterized in that the classifiers are charged with water. 5. The method according to item 1-4, characterized in that the mixing ratio of water / ash for the hydraulic removal of ash in landfills can be adjusted in accordance with the measured quantity ratio Gesamtasche to ashes obtained for secondary raw material constant and that the balance of the individual Aschebreipumpen accordingly the ash - amount of water are automatically switched on or off.