- •Recovered Paper and Recycled Fibers
- •Isbn: 3-527-30999-3
- •Introduction
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •2006, Isbn 3-527-30997-7
- •Volume 1
- •Isbn: 3-527-30999-3
- •4.1 Introduction 109
- •4.2.5.1 Introduction 185
- •4.3.1 Introduction 392
- •5.1 Introduction 511
- •6.1 Introduction 561
- •6.2.1 Introduction 563
- •6.4.1 Introduction 579
- •Volume 2
- •7.3.1 Introduction 628
- •7.4.1 Introduction 734
- •7.5.1 Introduction 777
- •7.6.1 Introduction 849
- •7.10.1 Introduction 887
- •8.1 Introduction 933
- •1 Introduction 1071
- •5 Processing of Mechanical Pulp and Reject Handling: Screening and
- •1 Introduction 1149
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •150.000 Annual Fiber Flow[kt]
- •1 Introduction
- •1 Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •Void volume
- •Void volume fraction
- •Xylan and Fiber Morphology
- •Initial bulk residual
- •4.2.5.1 Introduction
- •In (Ai) Model concept Reference
- •Initial value
- •Validation and Application of the Kinetic Model
- •Inititial
- •Viscosity
- •Influence on Bleachability
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Introduction
- •International
- •Impregnation
- •Influence of Substituents on the Rate of Hydrolysis
- •140 116 Total so2
- •Xylonic
- •Viscosity Brightness
- •Xyl Man Glu Ara Furf hoAc XyLa
- •Initial NaOh charge [% of total charge]:
- •Introduction
- •Isbn: 3-527-30999-3
- •Introduction
- •Isbn: 3-527-30999-3
- •Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •In 1950, about 50% of the global paper production was produced. This proportion
- •4.0% Worldwide; 4.2% for the cepi countries; and 4.8% for Germany.
- •1150 1 Introduction
- •1 Introduction
- •1 Introduction
- •Virgin fibers
- •74.4 % Mixed grades
- •Indonesia
- •Virgin fibers
- •Inhomogeneous sample Homogeneous sample
- •Variance of sampling Variance of measurement
- •1.Quartile
- •3.Quartile
- •Insoluble
- •Insoluble
- •Insoluble
- •Integral
- •In Newtonion liquid
- •Velocity
- •Increasing dp
- •2Α filter
- •0 Reaction time
- •Increasing interaction of probe and cellulose
- •Increasing hydrodynamic size
- •Vessel cell of beech
- •Initial elastic range
- •Internal flow
- •Intact structure
- •Viscosity 457
- •Isbn: 3-527-30999-3
- •1292 Index
- •Visbatch® pulp 354
- •Index 1293
- •1294 Index
- •Impregnation 153
- •Viscosity–extinction 433
- •Index 1295
- •1296 Index
- •Index 1297
- •Inhibitor 789
- •1298 Index
- •Index 1299
- •Impregnation liquor 290–293
- •1300 Index
- •Industries
- •Index 1301
- •1302 Index
- •Index 1303
- •Xylose 463
- •1304 Index
- •Index 1305
- •1306 Index
- •Index 1307
- •1308 Index
- •In conventional kraft cooking 232
- •Visbatch® pulp 358
- •Index 1309
- •In prehydrolysis-kraft process 351
- •Visbatch® cook 349–350
- •1310 Index
- •Index 1311
- •1312 Index
- •Viscosity 456
- •Index 1313
- •Viscosity 459
- •Interactions 327
- •1314 Index
- •Index 1315
- •Viscosity 459
- •1316 Index
- •Index 1317
- •Xylose 461
- •Index 1319
- •Visbatch® pulp 355
- •Impregnation 151–158
- •1320 Index
- •Index 1321
- •1322 Index
- •Xylan water prehydrolysis 333
- •Index 1323
- •1324 Index
- •Viscosity 459
- •Index 1325
- •Xylose 940
- •1326 Index
- •Index 1327
- •In selected kinetics model 228–229
- •4OMeGlcA 940
- •1328 Index
- •Index 1329
- •Intermediate molecule 164–165
- •1330 Index
- •Viscosity 456
- •Index 1331
- •1332 Index
- •Impregnation liquor 290–293
- •Index 1333
- •1334 Index
- •Index 1335
- •1336 Index
- •Impregnation 153
- •Index 1337
- •1338 Index
- •Viscose process 7
- •Index 1339
- •Volumetric reject ratio 590
- •1340 Index
- •Index 1341
- •1342 Index
- •Index 1343
- •1344 Index
- •Index 1345
- •Initiator 788
- •Xylose 463
- •1346 Index
- •Index 1347
- •Vessel 385
- •Index 1349
- •1350 Index
- •Xylan 834
- •1352 Index
Impregnation
COUNTERCURRENT
COOKING
CONCURRENT
COOKING
WASHING
Extraction
liquor
White liquor
DILUTION /
DISCHARGE
STEAMING
Energy,
white liquor
Energy,
wash filtrate
FLOW OF CHIPS
NET FLOW OF LIQUOR FLOW OF LIQUOR
Energy,
white liquor
Fig. 4.142 Typical Modified Continuous Cooking (MCC) process steps and flow regime.
extraction screens, as well as its integration into the two-vessel system are shown
in Fig. 4.143. If the digester in a two-vessel constellation is of hydraulic design, it
is equipped with a stilling well instead of the top separator.
Top circulation
liquor return
Chips and liquor
from feeding system IMPREGNATION
VESSEL
Chips and liquor
to digester
Bottom circulation
liquor return
BOTTOM Steam
CIRCULATION
HEATER
BOTTOM
CIRCULATION
PUMP
Fig. 4.143 Typical impregnation vessel in a two-vessel continuous cooking system.
386 4 Chemical Pulping Processes
In contrast to hydraulic digesters, steam/liquor phase digester have an inverted
top separator, where the chips are conveyed upwards inside the screen. The liquor
needed for top circulation flows back through the screen, while the chips and
excess liquor overflow from the separator into the steam phase. Since in the
steam/liquor phase digester the chips reach above the liquor level, direct steam
can be applied for chip heating. This has some disadvantages, such as dilution of
the extraction liquor, the related additional load on the evaporation plant, and a
reduced amount of live steam condensate returned to the boiler house. Steam/
liquor phase digesters allow compaction of the chip column to be influenced by
the height of chips standing above the liquor level.
4.2.8.3.5 Extended Modified Continuous Cooking (EMCC) and IsoThermal
Cooking (ITC)
Extended Modified Continuous Cooking [11]and IsoThermal Cooking [12]mark
the consequent prolongation of the ground broken by MCC related to the equalizing
of alkali profiles and co-utilization of washing zone volume for cooking and
washing.
A typical configuration of an EMCC/ITC single-vessel hydraulic digester is
shown in Fig. 4.144. The initial process steps up to countercurrent cooking corre-
Steam
Wash filtrate
Circulation transfer
White liquor
WASH
HEATER
COUNTERCURRENT
COOKING
HEATER
CONCURRENT
COOKING
HEATER
Pulp
Extraction
liquor
Fig. 4.144 Typical EMCC/ITC single-vessel hydraulic digester [12,13].
spond to the MCC technology described above. The additional element of EMCC/
ITC lies in the extension of the cooking zone down to the lowest set of screens
(see also Fig. 4.145).
There is no more dedicated high-heat washing zone between strainers. White
liquor is added not only to the top circulation and countercurrent cooking circulation,
but also to the wash circulation. At the same time, the temperature of the
wash liquor is raised to a point where the cooking temperature is also reached in
the extended zone. In Fig. 4.144, this means that the cooking temperature of typically
150–165 °C is maintained in the digester from the first set of screens down
to the last.
The split of white liquor between the points of addition must ensure that a
minimum residual alkali concentration is maintained in all liquors at all times, so
that the detrimental re-precipitation of dissolved organic compounds is safely
avoided. From a process perspective, EMCC and ITC are widely similar. Installation-
wise, EMCC requires only one wash circulation, whereas ITC uses two sets of
wash circulation loops with individual heaters.