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Zawartość zarchiwizowana w dniu 2022-12-27

DRYING AND COOLING MACHINE FOR GRANULITE AND OTHER GRANULAR MATERIALS

Cel

The purpose of this project is to test a new type of drying drum for granulite and other granular materials, which, in conjunction with heat recovery methods and the utilization of waste heat, should achieve an energy saving of about 34% compared with conventional methods. This corresponds to an annual oil saving of about 470 toe.
Alterations, subsequent work :
After trial runs, several elements had to be replaced, altered or re-ordored. The Krupp burner was re-ordered. To start with, we had problems with the burner from the firm of Kleinewefers. After controls, subsequent work and improvements, this burner is now working perfectly. The drive was altered. The gear drive was replaced by a chain drive. The electrical controls were altered. regulation apparatus, automatic parts were altered, improvement, worked on etc.
Planned alterations for new plant :
a) Mechanical twist filters are no longer permitted as filters; in future, special cloth filters must be fitted.
b) The angle of the drying drum must be some degrees higher, making installations easier and the performance higher.
c) A sand sluice must be installed at the suction part for the exhaust gases, causing less sand in the exhaust gases.
d) The burner should be constructed with a smaller volume and greater performance, producing a smaller surface to the outside and better cooling by the compression air on the outer casing.
e) Large-scale planning, new planning, thus less conveying equipment necessary.
f) Regulation of the sand supply automatic with maximum heating performance of the burner plant, thus higher total performance.
g) Reinforcement of the rolls and the drives, thus higher performance of the entire plant, thus higher degree of efficiency.
The plant has been completed and has been running flawlessly for some months.
The plant was planned for about 32 t/h of dry sand. However, an average value of about 43 t/h has resulted. This is extraordinarily positive.
In the planning of the plant, an annual saving of oil of about 470 tons was planned with an annual performance of 116000 tons of dry sand. In accordance with results available, we will only have a saving of about 210 tons of oil per year. This is to do with new legislation in the FRG.
In the planning of the plant, 350 mg of dust were admissible in the exhaust gases.Today only 50 mg of dust are admissible in the exhaust gases. Thus, a different dust filter plant is necessary as a cloth filter plant. However, these plants only work at temperatures which are a good 30 deg above the dew point.
Heating of the exhaust gases is therefore necessary.
Saving with 116,000 t dry sand = 210 t heating oil
100,000 t = 180 t heating oil
1 t = 1.8 kg heating oil
In the planning of the plant, the prices for heating oil were at 0.65 DM. On the other hand, the price for heating oil in November 1988 was at 0.25 DM. Naturally, the planned financial saving cannot come about.
It is to be expected that the price for heating oil will rise again in the years to come. In cases of new plants, the development costs, alteration costs, improvement costs will not come about in this form.
A patent application has been made for a new type of drying drum for the drying of granulite. Its operational efficiency is to be demonstrated in this demonstration project. The drum consists of an intensive drying zone and a re-evaporation zone. The combustion gases from an oil burner heat the granulite to more than 100 deg. C in the intensive drying zone, whereby approximately 75 % of the moisture in the sand evaporates.
The sand enters the re-evaporation zone, which is operated at a slight vacuum. This process causes re-evaporation to the necessary residual moisture content, and is supported by hot, dry air from the downstream sand cooling (heat recovery).
The combustion gases from the intensive drying zone and the dry air from the re-evaporation zone, including the water vapour fractions, are extracted in the central section of the drum. The purification of these exhaust gases is carried out in the dust separator. The compressed air needed in the combustion and transportationproceeses (6-8 bar) is produced by compressors. Naturally, dry air is produced as cooling air. This is used as combustion air for the oil burner (heat recovery).
In comparison with conventional method, the specific energy demand for granulite drying is planned to be reduced by about one-third by the combination of a drying process with re-evaporation and heat recovery. The necessary new components are integrated into operational plant already in existence in Koenigslutter.

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Koordynator

SCHLINGMEIER QUARZSAND GMBH & CO. KG
Wkład UE
Brak danych
Adres
ACKERSTRASSE 8
3301 SCHWULPER
Niemcy

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