METHOD, PROCESS AND APPARATUS FOR CONVERTING WOOD, WOOD RESIDUE AND OR BIOMASS INTO PULP

METHODE ET INSTALLATION DE CONVERSION DU BOIS, DES RESIDUS DU BOIS ET DE LA BIOMASSE ET PATE

English Abstract

ABSTRACT


A method, process, and apparatus are described wherein
includes conveying means for feeding chips and wood residue in a
continuous fashion for chemical pretreating, compressing,
deairing, dewatering, pressure steaming, pressure releasing, all
in accordace with predetermined time intervals, concentration of
chemicals in relation to fibre dry weight and retension time in
pressure steaming vessel, defibrating chips and wood residue,
means to interpret rate of feed to control residue movement
throughout the process, according to a predetermined schedule,
stored in the memory to further advance the defibrated residue
into refiner and further discharging the refined pulp for other
treatment.

Claims

The embodiment of the invention in which an exclusive
property of privilege is claimed are defined as follows:



1. A process of producing pulp from tree chips, sawmill
residues, wood or vegetable fibres comprising the
combination in sequence of the steps of:


conveying of vegetable fibres for a pretreatment,
impregnation with chemicals, compression of vegetable fibres
to extract air between the fibres and to extract some of
the liquid from the fibres, followed by loading sequence step
carried out by one of the following: pocket valve, loading
screw, or vegetable fibre plug created by mechanical or
hydraulical means into pressurized steam vessel, followed
by hydrolytic reaction at preselected steam pressure,
temperature and retention of said vegetable fibre in
the said pressurized steam vessel, followed by releasing
the vegetable fibres into decompression chamber for de-
fibration, followed by pulping, using either atmo-
spheric or pressurized refiners, followed by screaning,
cleaning of the produced pulp, all parameters for each
individual step are predetermined in advance and are
programed in an integrated control system.


2. Apparatus including an integrated system for producing
wood or vegetable pulp from wood or vegetable fibres
consisting of the combination in sequence of the following

apparatus parts, assemblies and units having a chemical
pretreatment metering means of the wood or vegetable fibre,
followed by metering means of said fibres into
compression chamber, followed by compressing means,
followed by means to activate one of the following: pocket
valve, loading screw or residue plug created either by




mechanical or hydraulical means to discharge said wood or
vegetable fibres into the pressurized steam vessel, followed
by means to complete the chemical pretreatment by mixture of
chemicals and steam, followed by means to inject the
chemicals and steam mixture into the steam pressure vessel,
followed by means to move the wood or vegetable fibres inside
the steam pressure vessel, followed by means for activating
the said wood or vegetable fibres moving means according to
predetermined information received from the residue metering
means, followed by means to unload wood or vegetable fibres
from steam pressurized vessel into decompression means,
followed by means to release the fibres from decompression
means to dozing means, followed by transportation and conveying
means of the decompressed said fibres to diffusion washers or
applicators of chemicals followed by transportation and
conveying means of washed and chemicaly treated said fibres
into the refining means.


3. An integrated control system as claimed in claim 2 which
further includes a first scanning means at the infeed of wood
and vegetable fibres in form of chips or residues, input data
receiving means for interpreting the data received from the
first scanning means and for measuring the moisture content
of the residue and weight-volume input according to the
predetermined parameters, means associated with said control
system for activating a speed control of the residue infeed,
measuring means controlled by the control system means of the
residue flow control system based on said data to introduce
chemicals in solution or in dry form into the residue flow,
means for controlling one of the following: pocket valve, or
loading screw or residue plug activity, further includs means
to activate the discharging of residues into a pressure vessel,

means related to flow of residues into a residue
compression means, means to interpret rate of feed to





control the residue movement in a steam pressure vessel
according to the predetermined schedule stored in a memory,
sensing means associated with discharge of residues from
steam pressure vessel, input data receiving means for
interpreting and controlling the refining mechanism and
refining according to a predetermined refining patterns
stored in the memory, the measurement is done by sensing
means located in strategic areas of each step.


4. A process according to claim number 1 of converting
wood chips, wood residues and vegetable fibres into wood
pulp including process step of protection the said fibre
against subsequent degradation, by binding of metal cations
present, with completing agents, process step of chemical
treatment with sulfonating agents in order to introduce
hydrophilic sulfonated group in wood or vegetable fibres,
process step of chemical treatment with oxidating agents in
order to form hydrophilic groups, hydroxide groups, carboxylic
groups, hydroperoxide groups, aldehyde groups on wood or
vegetable fibres or residue surface, process step of chemical
treatment with antraqinon in combination either with sodium
hydroxide and sodium sulfite or sodium bisulfite in order
to form hydrophylic groups on residues and to facilitate
lignin modification, process step of residue compression,
decompression and process step of alternating compression,
decompression, compression in order to assure air removal and
subsequent chemical penetration of chemicals into wood,
vegetable fibre or residue, process step of complementary
chemical treatment of said fibre when introducing it into a
pressurized steam vessel, process step of physico-chemical
reaction inside of pressurized steam vessel, process step

of defibration in a decompression chamber, process step of
washing and displacement of chemicals from defibrated products
in diffusion washers, process step of atmospheric refining





or process step of pressurized refining, process step of
screaning and cleaning of the produced pulp.


5. Process according to claim 1 includes the step wherein
complexing of the said wood and vegetable fibre is carried out
employing one or more of the following complexing agents:
DTPA Sodiumdiethylenetriaminpentaacetate in a concentration
range of 0.1% to 5.0%,
TPF sodiumtripolyphosphate in a concentration range of 0.1% to 5%
ethylene diamintetraacetic acid EDTA in a concentration range of
0.1% to 5%,
nitriloacetic acid in a concentration range of 0.1% to 6.0%,
triethylamin in a concentration range of 0.1% to 7%,
citric acid in a concentration range of 0.1% to 7%,
the step wherein sulfonation is carried out employing one
or more of the following sulfonation agents:
Na2SO3 sodium sulfite in a concentration range of 0.5%
to 15.0%,
Na2SO3 sodium sulphite in a concentration range of
0.5% to 15% plus NaOH sodium hydroxide in a concentration range
from .1% to 7.5% in case of broad leaf species,
the step wherein oxidation is carried out employing one or
more of the oxidation agents:
hydrogene peroxide in a concentration range of 1% to 20%,
sodium silicate in a concentration range of 0.1% to 5.0%,
magnesium sulphate in a concentration range of 0.1% to 3.0%,
pH is adjusted if necessary by sodium hydroxide in a
concentration range of 0.1% to 10.0%,
sodium peroxide Na2O2 in a concentration range of 1% to 20%,
sodium silicate in a concentration range of 0.1% to 5%,
magnesium sulphate in a concentration range of 0.1% to 5%,

ClO2 in a concentration range of 0.1% to 20.0% and pH in
a range of 4-6.5, temperature in a range of 40°-60°C,
NaClO2 in a concentration range of 0.1% to 20% pH in a range


11



of 4-12, temperature in a range of 40°-60°C,
peracetic acid in a concentration range of 0.1% to 20%,
ozone O3 in a concentration range of 0.1% to 8%,
MgSO4 in a concentration range of 0.1% to 4.0%,
NaOH in a concentration range of 0.1% to 4%,
oxygen °2 in a concentration range of 1% to 10%,
MgSO4 in a concentration range of 0.1% to 4%,
NaOH in a concentration range of 1% to 4%,
BIS t-butylperoxide diisopropylbenzene in a concentration range
of 1% to 10%,
Di-t-butyl peroxide in a concentration range of 0.1% to 10%,
Di-cumylperoxide in a concentration range of 0.1%to 10%,
t. butyl cumyl peroxide in a concentration range of0.1% to 10%,
all percentages are calculated by weight related to dry weight of
fibres, the step wherein compression and decompression is
carried out in an range of 5-2-5-2-5 atms., in a range of time
of 1 to 15 minutes, temperature in a range of 20°-120°C, said
wood or vegetable fibres in a concentration range of 1% - 30%,
the step wherein complementary chemical addition is carried out
in a concentration of 1% -5% of sulfonating or oxidating
agents at the entry in to steam pressurized vessel,
temperature in a range of 130° C to 220° C, saturated
steam pressure in a range of 0.5 MPa to 2.5 MPa, time in
a range of 10 seconds to 30 minutes, wherein the step of
defibration is carried out in decompression chamber to
atmospheric pressure, the step wherein diffusion washing or
chemical addition of sulfonating, bleaching or completing
agents are followed by the step wherein atmospheric refining
is carried out in a concentration range of 5% to 25%,
freeness in a range from 700 to 50 CSF(Canadian Standard
Freeness), or the step wherein pressurized refining is
carried out in a pressure range of 1.5 - 15 atms., in a

consistency range of 5% - 40%, freeness in a range from 700

12

to 50 CSF followed by the step of non co.mpulsory washing,
screening and cleaning of the produced pulp.


"CLAIMS SUPPORTED BY SUPPLEMENlARY DISCLOSURE"


6. Process of brightening the refined pulp obtained
by the process of claims 1, 4 or 5, comprising the step
wherein bleaching of refined pulp is carried out
employing one or more of the bleaching agents:
Hydrogene Peroxide H2O2 in a concentration range of 0.5% to 10
Sodium Peroxide Na2O2 in a concentration range of0.5% to 10%,
Magnesium Sulfat MgSO4 in a concentration range of 0.1% to 2%,
Sodium silicate Na2SiO3 in a concentration range of 1.0%
to 4% as a buffer,
DTPA in a concentration range of 0.1% to 0.5%,
Sodium hydroxide NaOH in a concentration range of 1.0% to 5%
in a range of pH 9-11 adjustement, at temperature range of
40°C to 70°C, at retention time of 60 to 120 minutes, at
consitency range of pulp 12% to 40% of dry fibre weight
base,
Oxygen O2, at pressure range of 2 to 6 atmospheres, at
temperature range of 80°C to 140°C, at retention time
range of 45 minutes to 120 minutes,
Ozone O3, at pressure range of 1 to 3 atmospheres at
temperature range of 70°C to 150°C, at retention time
range of 40 minutes to 120 minutes, at pulp consistency range
of 12% to 40%, resulting in brightness increase of up to 32%
in the single stage bleaching sequence, includes the step wherein
brightness reversion protection is achieved by sulfur bioxyde
SO2 treatment in a concentration range of 0.1% to 1.0% and
retention time range of 5 minutes to 60 minutes, includes the

step, wherein noncompulsory water washing is carried out after
each bleaching agent reaction, all percentages being based
upon the dry weight of said veyetable fibres.


13

Description

~2~ 5~
l;he present invention relates to an apparatus for
converting tree chips, wood or vegetable fibres into pulp and
more particularly, to a process of producing pulp from
ve~e-table fibres compri~sinc~ the combinatior1 in sequence of
the steps of handling, conveying, chemical pretreating,
COrnpreSSinCJ, deairinc~, dewatering, pressure steaming,
pressure releasinq, refinincJ and bleaching.
It is well known the conventional production oE pulp by
~raft, Sulphite, Trqpr CTMP, SGlJ, R~1P, SC~P, BSK, HY~S, ~JSSC,
~d PBI-IK processes, is expensive, highly capital intensive,
high enercJy consumin(~ and enviro~entaly restrictive.
It is an alm of this present invention to providc a
simple, relatively low capital cost ec~uipment, in such an orcler
as to handle the residues in an economic manner, with relati~
vely low energy requirement while minimizin~ the creation of
rejects and minimizing the manual input.
A process in accordance with the present invention
includes the steps of conveying the vegetable fibres for a
pretreatment, impregnation with chemicals, then the
compression of the vegetable fibres in order to extract air
between the fibres and to extract some of the liquid from
the fibres. The compressed residues are then loaded throuqh
a pocket valve, loading screw or vegetable fibre plug created
by mechanical or hydraulical means into a pressurized steam
vessel where additional chemicals may be introduced with the
ste~m. In the pressurized steam vessel, the hydrolytic
reaction occurs at a preselected pressure, temperature and
retention time of said vegetable fibres. The vegetabLe fibres
are freely moved by means of a worm or ribon conveyo-r.
The speèd of the movement ot the ve(~etable fibres in the
pressure steamin~ vessel is variable. It is directly related
to the rate ot ~e~, volume of the fibre ancl the desired

steam treatrnent. At the encl of the pressure vessel, ~h~



~ .


2~
O chemically pretreated and pressure steamed residues are relea-
sed by means of a decompression chambre into a dozing bin. From
the dozing bin the residue fibres are transported and conveyed
into a refiner. A refining is executed by a disc refiner
under pressurized and or atmospheric discharge operation.
An apparatus in accordance with the present invention
includes an intergrated system having a chemical pretreatment
metering means in to the wood residue flow, metering means of
residues into a residue compression chambre, residue compressing
means, air a~d moisture relieve means from a residue compression
means, means to activate pocket valve of a compression means,
means to discharge a pocket valve into the pressurized steam
vessel, means to move the fibre residues inside the steam press-
ure vessel, means for activating the worm conveyor according to
predetermined infor~lations received from the residue metering
means, means of unloading fibre residues from a steam pressurized
vessel into a decompression means, means to release the fibre
residues from decompressed means to a dozing means, means trans-
porting and conveying the decompressed fibre residues into
the refining means.
A further feature of the present invention includes
a control system which includes a first scanning means at the
infeed of wood residues, input data receiving means for interp-
reting the data received from the first scanning means and for
measuring the moisture content of the residue and weight-volume
input according to the predetermined parameters, means associat-
ed with said control system for activating a speed control
of the residue infeed, measuring means controled by the control
system means of the residue flow control system based on said
data to introduce chemicals in solution and or in a dry form into
the residue flow, means for controling the pocket valve or fibre
plug activity, means to activate the discharging of vegetable

fibres into a pressure vessel, means related to flow of


,.


~2~L~25~5

vegetable fibres into a vegeta~le fibres compression means,
means to interpret rate of feed to control the residue movement
in a steam pressure vessel according to the predetermined
schedule stored in a memory, sensing means associated
with discharge of residues from pressure steam vessel~ input
data receiving means for interpreting and controling the
refining mechanism and refining accordin~ to a predetermined
refining patterns stored in the memory.
Ha~ing thus generally described the nature of the inv-

ention, reference will now be made to the accompanying
drawings, showing by way of illustration, a preferred embodiment
thereof and in which:
Figure 1 is a diagram illustrating the various steps
af a continuous process;
Figure 2 is a diagram illustrating the various
reactions and changes of properties of residues from wood
type form to pulp type form;
Figure 3 is illustrating step-by-step the process
sequence of converting wood residues into a marketable pulp;
Figure 4 depicts the process of brightening or
bleaching.
Referring now to the drawings and particulary to
figure 1, there is shown an integrated processing mill for con-
version of wood chips and or wood residues into wood pulp. An
embodiment of the integrated processing mill includes a chip
or residue conveyor 1 for conveying chips or wood residues,
a pretreatment station 2 for application of chemicals, chips and
residue level detector 17 for controling the flow of chips and
residues through the pretreatment station and for controling
the level of chemicals 4 in the first pretreatment station

2 a further a worm conveyor 3 for conveying residues from first
pretreatment station 2 on to a residue conveyor 5 leadi.ng into
second pretreatment station 6. A further scanner 18 may be




~2~;~50~;

provided for again measuring the residue volume from the
second pretreatment station 6 into the compression chamber 8
operating under a predetermined pressure, compressed residues
are then advanced through a pocket valve or fibre plug 9
through a steam pressure vessel 10, through a decompression
chamber 11 and 12 into a dozing bin 13 and from the dozing bin
through a washing station 14 or directly on to worm conveyor
15, bypassing the washing station,leading into the refiner
16. Refi.ned pulp is discharged into latency chest 19 and
further the refined pulp may be introduced in to the bleaching
station 20. Figure 2 shows reactions of chemical pretreatment
of vegetable fibres 20 by complexing agents 21 and formation of
hydrophylic group 22,23,24, 25, 26, 27, on wood surface,
creat:inc3 a bond 28 it also demonstrates formation of hydrophilic
group 22, 23, 24 on surface of residues 20 by oxidating agents 21.
Figure 3 is the step by step process sequence of che-
mical reactions by various pretreatment of residues:
~tep 1- rrrys to eliminate free metalic cations which may cata-
lize oxidation of SO2 to SO3,elimination is done
by complexing with complexing agent DTPA or others.
Free metal ~ DTPA-~-------- Metal-DTPA
(non-reactive
complex)
Example: Ee, Mn, Cu, Al, etcO Metals may be pressnt
in different valences.
To protect against oxydation, residues are pretreated
with DTPA -Sodium Diethylenetriaminopentaactate (.5-3% ) or
TPT - Sodium Tripolyphosphate
EDTA - Ethylen Diamietetraacetic Acid
-Nitriloacetic Acid
Further treatment is done by the following agen-ts:

Sodium Sulphite Na2SO3 (Equilibrium pH 9.3) or

Ozone- O3
or

25~i

!~ Oxygene or
Peracetic Acid or
ClO2 Bioxide of chlore or
NaClO2 or
NaHS~3 or
H2O2- Hydrogene Peroxide or Na2O2
Sodium peroxide or
Steps 2-5 are designed to form Hydrophylic group by:
-sulfonation and/or
-oxydation
The formation of Hydrophylic groups either by oxidation
and/or sulfonation is proportional to the concentration of
chemicalproducts, wood residue, time and temperature.
At constant concentration of residue and chemicals used,
the process is controlled by time and retention temperature.
In Step no. 2 and 3 determining factor for chemical
reaction is time, since the temperature is very low.
In the step number 4, it is the temperature which con-
trols the extent of sulfonation or oxidation. The speed
of the sulfonation or oxidation may be also varied by
concentration of the chemical product.
Further figure 3 depicts step by step the se~uence of
the process of pretreatment of residues, its defibration
and its refining as fo]lows:

Step 1- To prevent degradation by burning of residues which may
take place in residue pressure steaming vessel, residues
are mixed in solution of O5-3~0~ solution related to
dry weight of residues at ambiant temperature
and under atmospheric pressure.
Step 2- In order to form hydrophilic group on the surface of
residues the following treatment is made:

-with sulphonating agents; DTPA
Sodiumdiethylenetriaminopentaacetate and others

` ~Zl~S~S
-with oxidative agents; TPF as sodium
tripolyphosphate, ethylen diamietetraacetic acid.
This begins a topochemical reaction which consist in
diffusion of chemical agents inside of the wood resi-
dues and subsequently chemical reaction with the
wood substrate.
Step 3- In order to increase the efficiency of the reaction and
or the rate of diffusion the residues are introdu-
ced into a compression-decompression cha~ber.
0 Step 4- After the compression-decompression of residues, the
residues are trar~sferred into pressure steaming vessel,
to complete the saturation process of residues,a final
part of chemicals is introduced by steam at the
beginning of a steam pressure vessel, major parts
of hydrophylic groups are formed in the vessel due to
high temperature and time of retention.
Step 5- Treated residues leave the pressurized vessel into a
decompression chamber where de~ibration of residues
occures. Further, residues are conveyed to a dozing
~0 bin under atmospheric pressure.
Step 6- Defibrated residues are conveyed through a washing
station and/or they are conveyed without washing into a
refiner.
Step 7- Depending on the pre-determined quality of pulp,
refining of defibrated residues is directed to achie-
ve ~anadians Standard Freenes varying from 600 to 50 CSF.
This is achieved by using commercial atmosphe-
ric refinèrs and/or pressurized refiners.
According to the final product requirement,the pulp
could be used as it is and/or could be transferred to
other treatments as follows;bleaching treatment, curl
setting, latency, screening, or cleaning.

Z~

"SUPPL~MENTARY DISCLOSURE" r
Prior to noncompulsory bleaching the refined pulp is
washed, noncompulsury screened, cleaned, thickened and
preferably bleached in a single stage process. The
brightness increase of up to 32 points have been experienced
during laboratory and pilot bleaching trials with Hydrogene
Peroxide H202, Sodium Peroxide Na202, Oxygene 2 and Ozone 03
Magnesium Sulfat, Sodium Silicate, DTPA, Sodium ~ydroxyde
at pulp consistency range of 12% to 40~. Brightness reversion
protection have been succesfully achieved by non compulsory
diffusion washing and post treatment with Sulfur
Bioxyde S02.