DD235904A1 - METHOD OF BRUEDENWAER UTILIZATION FOR THE DRYING OF SHOULDERS - Google Patents

Abstract

The invention relates to a method for drying Schuettguetern, in particular koerniger brown coal, according to the principle of convective heat and mass transfer in Schuett- and fluidized beds, as well as in Gutstroemen taking advantage of the Bruederwaerme, anfaellt in another drying process and usually unused in the Atmosphaere is dissipated. The method is characterized in that the gaseous heat carrier is heated by the Brueder and then passed into a separate apparatus which operates on the principle of convective heat and mass transfer in Schuett- and fluidized beds.

Description

Field of application of the invention

The invention relates to a process for the drying of bulk materials, in particular granular lignite, according to the principle of convective heat and mass transfer in debris or fluidized beds and material streams taking advantage of the vapor heat, which is obtained in another drying process and discharged usually unused into the atmosphere becomes.

Characteristic of the known technical solutions

There are known ideas that in the drying process of granular goods such. As raw lignite, use as steam-air mixture resulting vapors for drying energy.

In some methods, the vapor is brought directly into contact with the raw lignite, which leads to ball grain formation and thus clogging of the dryer tubes on the incident side (DE-PS 103371).

In other methods, the vapor for direct heating of the coal bunker walls is used (DE-PS 449087). The technical complexity does not correspond to the energetic benefits, since the heat transfer in the unmoved coal bed is very bad. ^v .

Furthermore, it is possible to use the vapor as a heating medium for the tube dryer (DD-PS 2226, DE-PS 113665). However, the equipment required is so great that these methods have not prevailed. For other methods, a direct heat exchange between the vapors and circulating water is made, which is used for external use (DE-PS 578823, DE-PS 132540). The users of low temperature heat are present in the vicinity of raw coal dryers only to a small extent. Furthermore, the plants to be used are highly susceptible to contamination and corrosion.

Likewise, by using the Brüdenwärme hot air can be produced, which is fed into the dryer tubes. The energy benefits achieved here are very low, since the tube dryer can only absorb a limited amount of pressureless drying air. (DD-PS 143176)

Object of the invention

The object of the invention is the development of a method for drying bulk materials by utilizing the accumulated in another Trock'nungsprozeß and unused Brüdenabwärme, so that at the same final moisture content of the dry matter is saved in total heat energy. Thus, the specific steam required at higher throughput or reduced the absolute and specific steam demand at the same throughput of the dry material.

Explanation of the essence of the invention

The invention is based on the object to develop a method for waste heat utilization in the drying process, especially in tube dryers of the lignite industry. It should be the Brüdenwärme a suitable heat transfer medium, z. As air, another drying process are supplied, in which the heat transfer according to the principle of convective heat and Stoffaustausqhes emits in heaps and bulk flows its heat.

According to the invention, the problem of the use of vapor heat is solved in that part or all of the heat of the vapor is transferred to another heat transfer medium, e.g. Air, transferred and this is fed to a separate drying process. This separate drying process is based on the principle of convective heat and mass transfer. Here, the disadvantages of the low-temperature heat are compensated by a good heat and mass transfer, thereby making the low-temperature heat available for use in a drying process. In certain applications, heating of the heat carrier is possible beyond the temperature level achieved by the vapors.

, embodiment

The vapor stream of a tube dryer in the briquette factory gives off its heat content to an air flow. This heated air stream is fed to an apparatus that works on the principle of convective heat and mass transfer, and used there for drying of bulk materials. Optionally, the air flow upstream of the convection dryer can also be heated up.

Claims (2)

Invention claim: 1. A method of Brüdenwärmenutzung for the drying of bulk materials, especially lignite, characterized in that the gaseous heat carrier is heated by the vapors and then passed into a separate apparatus, according to the principle of convective heat and mass transfer in debris or fluidized beds is working. 2. The method according to item 1, characterized in that a necessary heating of the heat carrier over the achieved by the vapor temperature level out with other heat sources is possible.