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Zawartość zarchiwizowana w dniu 2022-12-27

DISCONTINUOUS COOKING RDH (RAPID DISPLACEMENT HEATING) SYSTEM BY COLD BLDW ON A PAPER PULP PLANT

Cel

The project consists in the application to a discontinuous cooking paper pulp plant of the proposed system instead of the conventional one, obtaining a substantial energy saving.
This installation needs new tanks for the hot black liquor, exchangers, valves, pumps, air conditioning system etc.
The power supply necessary to reach the cooking temperature at the degestor is much less than with the conventional system. One the warm and hot liquors are stored in tanks the digestors remains without enough power for self-emptying and its content is transferred to the blow-tank (cold discharge system). This innovative system gets lower process times and improve the paper quality.
The results are as follows :
- Consumption of thermal energy : net steam consumption of 0.6 Th/MT
has been achieved.
- Consumption of electric power : consumption is 35 kWh/MT on average.
- Daily pulp production is as expected, i.e. 350 MT/day.
Energy results are thus less than expected, while production agress with what was envisaged.
Annual energy saving currently 3237 TOE.
Final report submitted July 1992. The project was a technical success but the economic advantages were less than hoped from the Finnish technology used.
In a discontinuous conventional system, pulp cooking is made by rasing the digestor temperature up from 90-95 deg. C (normal temperature of white and black liquors, together with the cold chips) to 170 deg. C in order that the equation : vegetal + chemical products + heat = cellulose + non cellulosic products is accomplished proceeding to the discharge and heat recovery in the form of flash which is condensated, by heating cold waters.
With the system of cold discharge, the cooking starts at 155 deg. C to end at 170 deg, without performing a flash, since the hot liquid is displaced by other cold liquids and introduced in the next digestor.
The innovation in this case, for the energy economy consists in heating the liquors in the next cooking, instead of water and start the next cooking at 155 deg instead of 90 deg. C, ending at the same temperature.
This system can be applied to any mill of chemical pulps with any alkalin system and with discontinuous cooking process.
The temperature differences of cooking starting between 90-95 deg. C and 155 deg. C makes that thermical energy consumption would be :
. Conventional system : 4,0 GJ/ADT
. RDH system : 2,4 GJ/ADT
. Consumptions difference : 1,6 GJ/ADT
In the case of CELULOSAS DEL NERVION, S.A. with a production of 122.500 ADT/year (350 ADT/day) the energy saving should be of the order of 4.700 TOE/year.

Zaproszenie do składania wniosków

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Koordynator

CELULOSAS DEL NERVION SA
Wkład UE
Brak danych
Adres
BD LA PILASTRA, S/N
48200 DURANGO
Hiszpania

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