FR2549847A1 - Process and device for the manufacture of granulates from at least one liquefied solid - Google Patents

Abstract

Process for the manufacture of granulates from at least one liquefied solid capable of passing through a plastic state during its solidification and device for its use. According to this process the liquefied solid is poured onto a cushion of cold water flowing at high speed. Application in refinery and to the bulk packaging of asphalts.

Description

 The present invention relates to a method for manufacturing granules from at least one liquefied solid capable of going through a plastic state during its solidification. It also relates to a device for implementing this method.

 By way of example, the invention applies to the manufacture of granules of bitumen or asphalt and more generally of any similar solid having a sufficiently low softening point.

 In most known methods for producing bitumen blocks, liquefied bitumen is introduced into cooling tanks. Reference may be made to the description of French patent No. 2,118,535: "Method for manufacturing blocks from liquefied solids and machine for implementing this method" which makes a detailed study of this prior art.

 This same French patent 2,118,535 provides more precisely a process for manufacturing bitumen sections, intended to be pressed and coated. According to this process, the liquid bitumen is extruded in the form of continuous and separate beads of small diameter. Each cord is kept in a jacket of cooling water until a plastic state is obtained. After stretching their ends, the cords are divided into small sections and wringing.

 The method according to this patent 2,118,535 is complicated and requires a sophisticated installation for its implementation. In addition, it is ill-suited to large-scale operation, as is the case in a refinery, for the treatment of asphalt from the deasphalting of distillation residues, or more generally, for the bulk conditioning of asphalts / bitumens. .

The object of the invention is therefore a very simple means of manufacturing solid particles from at least one liquefied solid, this means also having to allow a continuous manufacturing process
The method according to the invention is essentially characterized in that the liquefied solid is made to flow over a cushion of cold water flowing at high speed.

 Preferably, the flow on the cold water cushion takes place in at least one open and inclined chute which may have any suitable section, for example a half-cylinder or a half-truncated cone. This chute, traversed lengthwise by a stream of cold water of small thickness essentially fulfills two roles.

 In its first half or first third of its length, it involves first cooling the external surface of the asphalt net which, flowing vertically, will come into contact with the stream of water and will therefore not be able to enter. contact with the metal wall.

 Note that if such contact occurs, it would result in a certain agglomeration of bitumen or asphalt against the metal wall, causing the formation of agglomerates of various shapes and sizes significantly larger than those of particles which are normally manufactured by the process which is the subject of the present invention.

It is precisely the purpose of the latter to achieve contact only between the asphalt net and the stream of water allowing-hardening by very rapid cooling the surface of the net and thus pass it very quickly from the fully liquid state to a semi-rigid state in which it will continue its total cooling while retaining its initial shape.

It is precisely so that total cooling can be achieved that the chute already mentioned at a relatively large length. We can therefore say that this cooling as complete as possible of the rigid asphalt wire will be the goal of the second half or the last two thirds of the pipeline already mentioned. The residence time in this part can be adjusted by lateral injections of cold water placed, for example, at the midpoint of the pipeline or at its first third, all the details of the arrangement being able to depend on both a type asphalt or bitumen to be cooled, and in particular the density, its heat capacity, its softening or penetration point (characterized by the test described in the Standard
French T 66008). Other parameters may also play an important role, in particular the flow of asphalt to be solidified, and the temperature of the water.

 It should also be noted that when the hardened asphalt thread is shaped, that is to say when the hot asphalt and the cold water film are brought into contact, it does not occur. no release of water vapor which is troublesome for the immediate environment of the installation, costly in operating costs, or dangerous for the personnel working in the workshop where the equipment will be installed. Once at the end of the pipe, the water + bitumen (or asphalt) assembly, cooled and shaped into a filament, will fall into a tank where the cooling can eventually be completed, but whose main function is to serve as suction volume to a system for separating the water + granules mixture, which in the example cited is an Archimedes screw.

 This can also be a conveyor belt fitted with perforated baskets, or any other reliable mechanical system with low energy consumption. The suction hopper secured to this screw is immersed in the tank and receives the water + granules mixture. The screw driven by a motor with manually or automatically adjustable speed allows both to drip the asphalt or bitumen shaped, as well as to adjust the length of the sticks obtained. The water discharged by the Archimedes screw flows against the flow of the asphalt's direction of elevation. At the top of the screw, the asphalt is obtained drained and can possibly be collected in the state, for example in barrels or various containers. At this stage, one can also carry out a complete drying "in line" by installing at following the screw, a drying apparatus using a ventilation of temperate air passed through by conveyor, the speed of unwinding of which makes it possible to adjust the residence time necessary for total drying.

But the advantages and the other characteristics of the invention will appear more clearly on reading the description below, made in a non-limiting manner with reference to the accompanying drawings in which - Figure 1 is a general view of an installation according to the invention, - Figure 2 is a top view of the trunking, - Figure 3 is a side view of the trunking, - Figure 4 is a section on IV-IV of Figure 3, - Figure 5 shows a variant of
realization of the chutes.

 The installation shown in FIG. 1 comprises a set (2) of four troughs (3), (4), (5) and (6) arranged on a frame (7). The assembly is inclined towards the lower end (10).

 This end (10) is located above the tank (11) which constitutes a suction volume for the Archimedes screw (12). The screw (12) is rotated by the motor (13).

 The installation shown comprises a drying installation (14) comprising a conveyor (15) passing through a zone (16) for ventilating temperate air blown by the pump (17). The granules are collected in the tank (18).

The introduction of the liquefied solid takes place in the upper part (20) of the chutes (2) by an injection system (21) comprising four nozzles (22) each provided with a valve (23)
Water is introduced into the installation in the upper part (20) by four nozzles (24) and their corresponding valves (25). The installation also includes a complementary injection (26) of cold water which is located approximately in the middle of the assembly (2) and provided with a valve (27).

 The installation described was used for the shaping of an asphalt coming from the deasphalting with heavy solvent of a vacuum distillation residue of an Arabian crude.

The vacuum distillation residue of this crude has the following characteristics
Density at 150C = 1.02 kg / m3
Viscosity at 1500C = 1130 Centistoke
Yield on initial gross = 18.6% by weight
The process for deasphalting with heavy solvent (pentane) of this feed is carried out in an installation similar to that which is described in European patent No. 0053535.

This results in the production of an asphalt which can correspond to the crude yield of approximately 6% and whose physical properties are as follows
Density at 150C = 1.272
Softening point = 1500C
"Ball and Ring Method"
(Standard NF T 66008)
This asphalt undergoes in the deasphalting installation a steam "stripping" necessary to remove the traces of pentane which could still be there, then flows in pipes maintained at around 3000C to a point of use. . It is precisely at this point that the apparatus which is the subject of the present invention and described above can be installed.

 Asphalt is produced at a flow rate of 600 kg / h and its flow is divided into four flows of 150 kg / h, each by means of a distribution ramp. With regard to this distribution ramp and more particularly the choice of the valves which equip it, it will be advantageous to use valves making it possible to regulate with the maximum of finesse the asphalt wire which will flow.

 A judicious choice will be that of adjustable needle valves, "STRAHMAN" type, well known throughout the bitumen manufacturing industry.

 The four asphalt streams leaving the unit at 3000C flow vertically on a film of water which lines the inside of the troughs (3), (4), t5) and (6). Referring more specifically to Figure 2, we note that the troughs (3), (4), (5) and (6) constituting the assembly (2) are converging towards their lower end (10), which allows to accelerate the evacuation of the product and also to decrease the volume of the tank (11).

There is shown in Figure 4 a section along
IV-IV of the assembly (2) and in FIG. 5, an alternative embodiment of this assembly according to which each chute (6), (5), (4) and (3) is semi-circular in its section through the plane IV-IV so that each chute is semi-cylindrical.

 However, the invention is not limited to the embodiments described. It encompasses all variants.

Claims (13)

1 - Process for the continuous production of granules from  at least one liquefied solid characterized in that  the said liquefied solid is made to flow on a cushion  cold water flowing at high speed. 2 - Method according to claim 1, characterized in that  the flow takes place in at least one inclined chute  whose length is sufficient to obtain solidifi  cation of said liquefied solid. 3 - Method according to claim 1, characterized in that  cold water is injected into said cold water cushion. 4 - Method according to claim 2, characterized in that,  after solidification, the mixture of solid and water  is collected in a tank where the solid occurs  mainly in the form of granules. 5 - Method according to claim 4, characterized in that  the solid is separated from the water. 6 - Method according to claim 5, characterized in that  the solid is dried. 7 - Device for the continuous production of granules from  at least one liquefied solid characterized in that it  includes at least one chute for the circulation of a  cold water cushion. 8 - Device according to claim 7, characterized in that  that said chute is inclined towards one end  lower. 9 - Device according to claim 8, characterized in that  that said lower end of the chute is located  opposite a tank constituting a volume of aspira  tion for a system allowing the separation of a  mixture of water and granules. 10 - Device according to claim 7, characterized in that  that the chute has an upper end provided  a cold water supply device. 11 - Device according to claim 7, characterized in that  that the chute has an upper end provided  a device for injecting the liquefied solid. 12 - Device according to claim 9, characterized in that  that the system of separation of water mixture and  granules opens, in the upper part, into a  pellet drying facility. 13 - Device according to claim 8, characterized in that  that each chute converges towards its end  lower.