Method and apparatus for processing a fibrous mass in a spiral shaped flow-typed tube cell

The invention is directed towards the method of processing of fibrous mass by a chemical agent and the set up needed for the conducting of the process. Fibrous mass is mixed with a gas transfer agent in the mixing cell and goes to the flow-type tube cell which is shaped like a spiral with the 1:18-1:60 ratio between tube and loop diameters. The chemical agent is transferred immediately to the reactor throughout the jets attached to the reactor lengthwise. The process is carried out in a turbulent regime of motion of the reaction mixture with the velocity of 1-50 m/s. The current invention allows to reach the higher effective processing of fibrous mass, to reduce the consumption of the chemical agent and to increase the quality of the processed material. It can be utilized in paper and pulp industry for the processing of cellulose using a bleaching agent.

TECHNICAL SECTION 
The current invention is concerned with the processing of fibrous substance 
by the use of a chemical agent and set up required which can be engaged in 
paper and pulp industry as well as bleach use. 
PRELIMINARY LEVEL OF TECHNOLOGY 
Presently, processing of fiber, as well as paper and pulp fiber, is 
fulfilled by the use of chemical agents with variety of methods. Some 
processes, like chlorine bleaching in the presence of suspended substrate 
(USSR Patent No 282053, 1970), chlorinating of paper and pulp fiber in the 
adsorption column (USSR Patent No 209964, 1968) or some methods of fiber 
bleaching, carried out with such gaseous agents as ozone, oxygen and 
chlorine in the column reactor (USSR Patent, No 365411, 1973), are well 
known. Some methods of fiber treating with gaseous agents with the use of 
certain devices, provided with a cycling transfer tape for maintenance of 
a proper mass stratum (USSR Patent No 544724, 1977), are also known. 
Nonetheless, all the methods reviewed are characterized by insufficient 
mass transfer in the reaction zone, furthermore, agent utilization 
constant and quality of the product are considered to be low. Chemical 
agents, engaged in these processes, do not allow to conduct the processing 
of highly concentrated fibrous mass and require a large amount of metal 
for equipment and complexity of service in use. 
The closest method to the needed one is a method of fiber processing 
through the agency of treating with a gaseous agent in the flow reactor, 
which beats all the faults revised above (Russian Federation Patent No 
903419, 993). This one can be used in the process of pulp and paper 
bleaching by a gaseous agent. Thus, fiber concentration over 15 percent, 
calculated from the dry substrate, can be achieved in the portions, 
transferred throughout the load cell to the mixing cell with the gaseous 
agent, followed by transfer of the reaction mixture to the stream cell, 
connected to the cell for accumulation of processed fiber. The main fault 
of the current method is that the mass transfer in the reaction zone is 
insufficient and there is no uniform distribution of the reagent mass in 
the volume. Therefore, low agent utilization constant occurs, and no 
proper quality of processed fiber can be attained (the estimated level of 
bleaching is no more than 55 percent). 
This invention is directed towards the high quality methods of fiber 
processing with a chemical agent which contributes uniform processing of 
material in the whole volume of the reaction mass, decreasing of agent 
consumption, high quality of processed fiber (in particular, increasing of 
bleaching level of the pulp mass), opportunity to process the fiber of 
high concentrations using the large number of various chemical agents, in 
gas or liquid conditions as well. 
DESCRIPTION OF THE INVENTION 
The task set is solved by the way of preliminary mixing of fiber with a gas 
transfer agent in the mixing cell, followed by the transfer of formed mix 
into the tube cell, which is spiral shaped and looped round the 
accumulation cell for processed fibrous mass with the 1:18-1:60 ratio 
between tube and loop diameters. Following this scheme, chemical agent is 
transferred throughout the jets, which are stretched lengthwise, and the 
process is conducted in a turbulent regime of the mass flow with the 
velocity 1-50 m/s. 
The difference between this method and the known one is that the chemical 
agent is transferred directly to the reactor from the jets attached to its 
sides lengthwise and the process is conducted in a turbulent regime of 
flow with the velocity 1-50 m/s. The reactor, so far, is spiral shaped and 
looped round the cell for accumulation of processed fiber, with the 
1:18-1:60 ratio between tube and loop diameters. 
Conducting of fiber processing in a turbulent flow of the reaction mixture, 
moving throughout the cell with the velocity 1-50 m/s, promotes the 
appreciable intensification of mass transfer processes in the reaction 
zone. The turbulent regime of flow of the reaction mixture is promoted in 
a certain interval of the velocities of motion and in the certain ratio 
between tube and loop diameters. Feed of a chemical reagent directly to 
the cell from the jets, attached to the sides of the cell, promotes the 
uniform processing of fiber in a whole volume of the reaction mass and 
allows to attain the additional mixing of the reaction mass. Fibrous mass, 
particularly dispersed by flow of the transfer agent in the mixing cell, 
is treated with the further dispersion, forced by restraints from the 
sides of the cell, moving with the velocity 1-50 m/s through the cell 
which is spiral shaped according to the 1:18-1:60 ratio between tube and 
loop diameters. This additional layer formation of fiber structure 
promotes the increasing of the reaction surface what induces up almost 100 
percent utilization of the chemical agent. Reaction mass analysis on the 
outlet from the reactor indicates that the chemical agent does not exist 
there any more. Specific spiral shape of the reactor, looped round the 
accumulation cell, provides the mobility of the device and reduction of 
the surface engaged. 
Required levels of mixing and dispersion of the fibrous mass and 
corresponding high efficiency of the process of treating with a chemical 
agent are reached in the certain intervals of velocity values of the 
reaction mass in the cell (1-50 m/s) and ratio between tube and loop 
diameters (1:18-60). As the reaction mass moves with the velocity less 
than 1 m/s, it causes some unstable conditions of processing for the 
motion of the reaction mass occurs in a pulsation mode, therefore all the 
dominant properties like whiteness, utilization constant, etc. are failed. 
As the velocity reaches over 50 m/s the process is characterized by 
abundant power utilization. Decreasing the current ratio between tube and 
loop diameters must induce unstable work of the reactor as well as in case 
of increasing of this ratio the quality of product becomes low. 
Following the current method, the fibrous mass is preliminary mixed with 
the transfer agent. This allows to conduct mixing with the 10-60:1 ratio 
between the masses of fiber and transfer agent. Increasing this ratio 
higher than 60:1 may result an accidental situation, caused by clogging 
the reactor, whereas the decreasing of the ratio lower than 10:1 is 
economically unreasonable. The chemical agent used in the process can be a 
gas like oxygen, ozone or chlorine or a liquid system like aqueous 
solution of chlorine dioxide or hydrogen peroxide. 
Since the chemical reagent is a gas there is no use of it as a transfer 
agent. In this case a part of the gaseous chemical agent enters in the 
mixing cell as a transfer agent and obtained mixture follows to the 
reactor. Residual part of the gaseous agent enters the reactor immediately 
from the jets, attached lengthwise. 
It is also possible to use air or distilled vapor as a transfer agent. As 
is often used as a transfer agent in case of processing the fibrous mass 
by the aqueous solutions of oxidant. 
The current method allows to process the highly concentrated fibrous mass 
with a concentration interval of the dry substance of 35-90 per cent by 
weight.

THE PREFERRED EMBODIMENT OF THE METHOD 
The device consists of the cell for mixing of the fibrous mass and the gas 
agent (1), provided with a device for loading the fibrous mass (2) and 
accommodation for the gas agent entry (3), which can be made like a tube 
feeding system, and the flow-type tube reactor contacted to the mixing 
cell, shaped like a spiral, looped round the cell for accumulation of the 
processed fibrous mass (5) with the 1:18-1:60 ratio between tube and loop 
diameters. 
Reactor is provided with the jets for chemical agent feeding system 
attached asides (4). The accumulation cell (5) attached to the reactor 
outlet is provided with a device for pumping of the processed mass (6) and 
provided with the accommodation for outlet of the utilized gas (7). 
The device (Russian Federation Patent No 903419 1993), known before and 
used for loading of the fibrous mass, consists of the bunker (8), feeder 
(9), enclosed in the shell (10), which provided with a perforation system 
(11) for gas ejection from the mass and the back valve (12). 
Extents and materials needed for distinct parts of the device depend on a 
type of the fibrous mass, chemical reagent, conditions of the process and 
reaction velocity. 
The method is conducted by the following way. 
Fibrous mass, impregnated with a reaction liquid (water base solution, for 
instance), is transferred to the bunker (8) of the feeding device (2) 
where, then, it is taken to the outlet by the feeder (9) where it is 
formed by pressure into the "mass stopper". During its formation the "mass 
stopper" loses the air which goes through the perforation holes and 
finally is taken off the loading device. Formation of the "mass stopper" 
is followed by increasing of pressure at the back valve (12). As soon as 
the pressure becomes higher than in the mixing cell the (1) back valve is 
opened and the portions of the fibrous mass go to the mixing cell (1). The 
gas transfer agent, transferred to the mixing cell (1) through the 
accommodation for its inlet (3), takes the mass apart to the fibers. 
Preferably, the gas agent is consumed in the 10-60:1 ratio between the 
masses of fiber and transfer agent. The fibrous mass emitted from the 
mixing cell and grinded to fibers is taken by the transfer agent to the 
flow-type tube reactor (4) which is formed like a spiral looped round the 
accumulation cell (5) with the 1:18-1:60 ratio between tube and loop 
diameters. The chemical reagent goes throughout the jets, attached 
lengthwise to the reactor, immediately. The velocity of the transferring 
mixture of fibrous mass with the transfer agent and the velocity of 
chemical agent feeding are varied in order to reach the reaction mass flow 
velocity of 1-50 m/s. The processed reaction mass is taken to the 
accumulation cell (5). In case of conducting the bleaching process of 
cellulose, the accumulation cell is a column of high concentration, where 
the utilized mass is accumulated and pumped through the agency of a 
specific device (6) to the further processing, according to the current 
regulation manual, and utilized gas is whether taken off through the 
output unit (7), recycled for secondary use or dumped into the atmosphere. 
The invention is illustrated by the following examples. 
EXAMPLE 1 
Paper and pulp mass pressed to the 30 per cent by weight content of the dry 
substance and impregnated with the reaction liquid (aqueous base solution) 
is treated with the bleaching agent. Lignin content in the primary product 
is equal to 30 .kappa. units. The process is conducted according to the 
following conditions. The bleaching agent is oxygen. The mix of air and 
oxygen is used as a transfer agent. The ratio between the masses of 
cellulose and transfer agent is 20:1. Process time is 3 minutes. The 
velocity of the reaction mass flow in the reactor is 1.33 m/s. The ratio 
between the diameters of tube and loop of the reactor is 1:26. The 
pressure in the reactor is 1 kg/cm.sup.2. The temperature in the reaction 
zone is 60.degree. C. The process is conducted according to the conditions 
listed above. After the process, lignin content in the cellulose mass is 
19 .kappa. units. Consumption of the reaction agent is 19.7 kg for a ton 
of cellulose. Analysis of the processed cellulose mass on the outlet of 
the reactor indicated the total absence of the bleaching agent in the 
volume of cellulose. 
EXAMPLE 2 
Cellulose mass with the same quality index as in the example 1 is treated 
with the bleaching agent. The process is conducted under the following 
conditions. Bleaching agent is a 1.5 percent water solution of the 
hydrogen peroxide. The air is used as a transfer agent. The ratio between 
the masses of cellulose and transfer agent is 20:1. Process time is 3 
minutes. The velocity of the reaction mass flow in the reactor is 1.33 
m/s. The ratio between the diameters of tube and loop of the reactor is 
1:26. The pressure in the reactor is 1 kg/cm.sup.2. The temperature in the 
reaction zone is 60.degree. C. The process is conducted according to the 
conditions listed above. After the process, lignin content in the 
cellulose mass was 19 .kappa. units. Consumption of the reaction agent is 
12 kg for a ton of cellulose. Analysis of the processed cellulose mass on 
the outlet of the reactor indicated the total absence of the bleaching 
agent in the volume of cellulose. 
For comparison, previously known method, used for bleaching of the same 
kind of cellulose (Russian Federation Patent No 903419, 1993), gives 27 
.kappa. units lignin content in the output cellulose mass. The bleaching 
agent can be observed on the outlet of the reactor. The utilization degree 
of the reaction agent is no more than 15 percent. 
According to the data listed above, the invention performed allows to 
conduct higher efficient processing of the fibrous mass by the reaction 
agent use and, as a result, to reduce the consumption of the reaction 
agent and to raise the quality of processed material through the agency of 
intensification of mass-transfer processes and uniform distribution of the 
reaction agent in the whole volume of the reaction mass. Current method 
and set up, developed for the realization of this method, allow to conduct 
the processing of highly concentrated fibrous mass with the use of a 
chemical agent in gas or liquid conditions as well, and the structure of 
the reactor appreciably reduces the metal volume needed for the equipment 
and the surface engaged.