FR2481310A1 - PROCESS FOR PRODUCING BRAI FROM PETROLEUM FRACTIONS, BRAI OBTAINED, DEVICE FOR CARRYING OUT THE METHOD AND USE OF THE BRAI - Google Patents

Abstract

BRAI MANUFACTURING PROCESS FROM OIL FRACTIONS, BRAI OBTAINED, DEVICE FOR IMPLEMENTING THE PROCESS AND USE OF BRAI. THE INVENTION RELATES TO A PROCESS FOR MANUFACTURING BRAI. THIS PROCESS IS A CONTINUOUS PROCESS CONSISTING OF SUBMITTING A RESIDUE OF VAPOR CRACKING OR THERMAL OR CATALYTIC CRACKING OF OIL CUTS OR FRACTIONS FROM SUCH RESIDUES TO A DOUBLE THERMAL CURING TO A TEMPERATURE AVOIDING RESINS FROM CARBONIZATION. SIGNIFICANT TEMPERATURE BETWEEN THE HOT PART OF THE WASHER 1 AND 15 AND ITS COLDEST PART, WITH A VIEW TO CAUSING A REFLUX OF THE LIGHT FRACTIONS INTO THE BELLY OF THE LIQUID MASS WHILE REMOVING THE UNDESIRABLE COMPOUNDS, THE FIRST WASTING 1 OR WHICH TAKES PLACE CATALYST UNDER LIGHT PRESSURE, AND THE SECOND DAMPER 15 BEING CARRIED OUT AT A LOWER PRESSURE AND AT A TEMPERATURE LOWER OR EQUAL TO THAT IMPLEMENTED DURING THE FIRST WALLING. THE EMBELLS OBTAINED CAN BE USED FOR THE PREPARATION OF CARBON OR GRAPHITE ELECTRODES, CARBON-CARBON COMPOSITE MATERIALS, REFRACTORY MATERIALS, MEMBRANES OR PLASTIC COATINGS AND THE MANUFACTURE OF METALLURGIC COKE.

Description

The present invention relates to a novel process for the manufacture of

  pitches from petroleum fractions. The

  pitches prepared in this way can be used in particular in

  of carbon electrodes used in aluminothermy, graphite electrodes used in electrometallurgy,

  carbon-carbon composite materials, refractory materials

  membranes, plastic coatings, for the

production of metallugic coke.

  The Applicant has described in these French patent applications 73 40152 and 76 19649, processes for the manufacture of pitches using residues of steam cracking of petroleum cuts consisting of carrying out a distillation followed by a thermal slump or by recycling during the mOrissement thermal vaporized light fractions or

  obtained otherwise, either by using a catalytic converter

  voiding a rapid and complete condensation of fractions

  unsaturated present in the diet.

  The applicant has also described in her French patent

  No 77 00103 a process for the production of pitches

  improved performance according to which

  steam cracking of petroleum fractions or fractions

  from said steam cracking residues, a heat treatment

  under a slight pressure maintaining a significant temperature difference between the hottest part of the treatment apparatus and its coldest part, in order to have a reflux of light fractions in the device

  thermal ripening and elimination of

  unwanted light Such a method makes it possible to obtain

  with good yields of oil pitches having

  : .0 satisfactory properties for the manufacture of electrodes.

  One of the main difficulties encountered in the processes of the prior art concerns the appearance of carbon deposition in the heating tubes or in the heat treatment devices. The shutter of some parts of

  the installation due to these deposits of carbon, prevents the

  continuous operation of the unit and it is often impossible

  to implement these processes for a prolonged period.

  On the other hand, the pitches resulting from these processes often have a relatively low thermal stability.

  also has drawbacks in the use of

  sage of these pitches especially in the manufacture of electrodes.

  Research conducted by the Applicant has shown that there are essentially two origins to the formation of carbon deposition. When the content of resins and

  in particular resins e that is to say the resins

  In the case of benzene or toluene, the amount of resins 6 settling and settling in certain parts of the plant is

  transform gradually into solid carbonization products.

  Moreover, when the temperature is too high the kinetics of carbonization of the resins 6 is very fast and

  coke deposits are hard to avoid.

  To obviate the demixing of S resins, avoid

  their concentration at any point in the manufacturing unit

  pitch cation and therefore provide a suitable heat treatment device avoiding stagnation of liquid pitch during the flow of the latter in any part of the unit. The Applicant has now discovered a continuous process for manufacturing petroleum pitches that makes it possible to overcome the drawbacks of the prior processes, in particular with regard to the thermal stability of the resulting pitches and the formation of coke deposits in the production unit. The process according to the invention also has the advantage of being flexible and of making it possible to obtain quality pitches.

  different covering a wide range of application.

  According to this process, steam cracking residues or thermal or catalytic cracking of petroleum fractions or fractions resulting from said residues are submitted to two successive maturing treatments in ripening devices called "ripener". Heat treatment in

  the first braking device is made under pres-

  a slight increase above atmospheric pressure in

  a significant temperature difference between the warmer part of the ripener and the cooler part so as to obtain a reflux of the light ends in the ripener and to eliminate unwanted volatile compounds. The heat treatment in the second maturing device is carried out

  under less severe pressure conditions and at

  eratures lower than or equal to those of the first ripener while also maintaining a significant temperature difference between the warm part of the ripener and its cooler part to also obtain in this case a reflux of the light fractions in said ripener and to eliminate the compounds

unwanted volatiles.

  The fact of working with two thermal ripeners in particular makes it possible to avoid accumulations of pitches and

  1 5 local overheating resulting in the deposition of coke in the

  tallation. The use of these two ripeners also allows

  to obtain a great deal of flexibility in the installation and

  prepare pitch of different quality according to the conditions

  temperature and pressure.

  The Applicant has also discovered that by operating in the second ripener, contrary to what is practiced in certain processes recommended in the prior art, under milder pressure and temperature conditions than those used in the first merger,

  compounds having improved thermal stability.

  Work under pressure and temperature conditions

  ture also helps to avoid the use of heat sources such furnace, exchangers between the two

  stages of ripening which reduces the risk of over-

  local heaters and therefore minimizes carbon deposits in

  the installation and the likelihood of clogging of these

  Nières. Moreover, this also has significant economic advantages, particularly with regard to

  energy consumption and investment costs.

  Finally, the process according to the invention avoids the implementation of a final stage of distillation or stripping of the pitch.

  The pressure conditions implemented in the first

  thermal ripener can increase the boiling temperature of the medium and thus increase the aromaticity of the

  product and to improve the quality of the final pitch while limiting

  both the increase of the softening point and the deterioration

  product. It is particularly possible, thanks to the pre-

  invention, by adjusting the pressure-temperature pair to determine the amount of light products removed and consequently the volatile content of the product leaving

ripener.

  External pressures to the claimed ranges according to the present invention would not eliminate the undesirable volatile compounds which would remain within the liquid mass and would significantly impede the reactions of

  condensation of heavier molecules.

  The temperature of the first stage of ripening

  fluence directly the kinetics of formation of the resins and

therefore that of carbon deposits.

  The temperature difference between the bottom and the head of the

  ripening helps to ensure partial reflux of

  light fractions in the ripening zone and therefore

  improve the yield of pitches. Such a treatment favors the reaction of the reactive molecules of the light fraction which are thus reintroduced into the ripening zone. Maintaining the temperature difference avoids the evaporation of some products contained in the ripener which could cause a decrease in the yields of pitches. The second ripening device essentially makes it possible to adjust the

  characteristics of pitch, mainly softening point

  > and the resin content e playing on the temperature, the pressure, the time of stays of the product in the second ripener. The subject of the present invention is therefore a method of

  continuous production of pitches using two

  -, 5 thermal maturing sitifs.

  Other objects will appear on reading the description.

  detailed examples.

248 1310

  The continuous pit preparation process according to the present invention is essentially characterized by the fact that

  that a steam cracking or cracking residue is subjected to

  thermal or catalytic cutting of petroleum fractions or fractions from said residue to a double treatment of thermal curing at a temperature avoiding the carbonization of the resins while maintaining a significant temperature difference between the hot part of the thermal curing device and its part the cooler to cause reflux of light ends into the liquid body while removing undesirable compounds, with the first curing taking place with or without a catalyst under slight pressure and the second curing being performed at a lower pressure and at a temperature less than or equal to

  1i implementation during the first ripening.

  The first thermal ripening is preferably carried out

  at a temperature between 3500 and 420WC and in particular

bind between 370 and 400WC.

  The pressure during ripening is greater than <0 atmospheric pressure and can vary up to 15 'bar. It is preferably between 3 and 12 bar (relative pressure). The temperature difference between the hottest zone known as the ripening zone and the coldest zone known as the partial withdrawal zone for the volatile products is between 20

  and 2000C and is preferably between 30 and 100 ° C.

  The temperature difference between the curing zone and the partial withdrawal zone of the volatile products is provided by conventional known means such as, for example, a refrigeration line described in the French patent application No. 77 00103 of the applicant, the use of products

  from a reflux balloon, etc.

  The duration of treatment in each treatment device

  The thermal term referred to herein as curing time or residence time must take into account the amount of product removed in the device. The ripening time can be defined by the following formula: Volume of the ripener 100 t Feed rate x 100 -% products eliminated In the first mirror the residence time is between 10 minutes and 10 hours and preferably between 1 and 6 hours.

  The second thermal ripening takes place at a temperature of

  between 300 and 380 ° C. and preferably between 350 and

  370 C this temperature being less than or equal to the temperature

  ture prevailing in the first ripener. The maturing time

  is between 5 minutes and 6 hours and preferably between 30 minutes and 4 hours. The pressure during this second heat treatment is lower than the pressure applied in the first ripener and is between 0 and bar and preferably between 0 and 5 bar (relative pressure). 1) The temperature difference between the ripening zone and the zone known as partial withdrawal of volatile products is

  between 10 and 150 C and preferably between 20 and 80 C.

  The temperature of the ripening zone of the second ripener is preferably 10 to 50 ° C. lower than the temperature of

  the ripening zone of the first ripener.

  The products used in the process according to the invention as a starting material are the heavy hydrocarbons obtained as by-products during steam cracking or

  thermal or catalytic cracking of petroleum hydrocarbons

  liers. The latter are usually light fractions obtained by distillation of the oil such as the light distillate (35-180 ° C) cut, the light diesel oil, the heavy oil for steam cracking, atmospheric distillation residues or vacuum distillation for cracking

  J0 thermal and vacuum distillates for catalytic cracking.

  lytic. These steam cracking, thermal cracking or catalytic cracking residues may be used in the same state or as a mixture with other steam cracking or thermal or catalytic cracking residues or fractions thereof, or with coal tars. from the pyrolysis treatment of coal at high temperatures, or with

  extracts obtained by solvent extraction such as

  fural, phenol, etc ... vacuum distillates of crude oils. In some cases, distillates

  with extracts a desulfurization treatment.

  The process of the invention may also be carried out using a pitch derived from a reactive distillation of the steam cracking residue carried out for example in a column.

packed or trays.

  The pitches obtained by the process of this

  invention have a softening point KRAEMER-SARNOW

  1C taken between 70 and 1300C and a density of between 1.10 and 1.35, a resin content of between 5 and 40%, a resins content of very low and preferably lower

  at 1% 0 and a Conradson index greater than or equal to 40%.

  The pitches thus produced have remarkable characteristics because of their low sulfur content and

  metals and are particularly well suited to be used

  in the development of carbon electrodes or

  phite, carbon-carbon composite materials,

  refractories, membranes or plastic coatings,

  for the manufacture of metallurgical coke.

  The invention therefore also relates to the use in these different applications pitches as defined above.

  Another subject of the invention is a device enabling

  both to implement the method as defined above

  and prepare the above-mentioned pitches. This device is essential

  characterized by the fact that it includes two

  the bottom of the first ripener receiving the feed

  preheated by heating means avoiding overheating

  heaters being connected to the second ripener, each of said ripeners being equipped (1) with a control system of the

  level of the liquid product contained in each of said ripened

  a valve on the duct leaving the bottom of each of said ripeners, for setting the curing time, (2) a device for withdrawing light distillates and gases produced during curing associated with a cooling device and a reflux flask for recycling in each of said ripeners as well as regulating the temperature difference between the ripening zone and the ripening head by means of a valve located

  between the reflux balloon and the ripeners.

  A device for implementing the method according to the invention will now be described to illustrate an implementation of

of the device.

  The figure represents a possible device for the

  production of pitches according to the invention.

  The feed is introduced in a first ripener 1

  line 2, it is brought to the temperature of ripening

  through heat exchangers 3 and 4 and

  a tubular oven 5 designed to provide progressive heating

  sif of food and avoid local overheating.

  The feed maintained liquid in the line 2 is relaxed at the pressure of the first ripener via the

  valve 6 and introduced into said ripener. The time of the matures-

  The product is regulated by means of fluid level control systems of the liquid product 8 contained in the ripener.

that actuates the valve 9.

  The light distillates and the gases produced during ripening are also withdrawn via line 10 and cooled via condenser 11 before arriving.

in the reflux flask 12.

  Adjusting the temperature difference between the ripening zone and the ripening head is provided by a temperature control system actuating a valve 13. The reflux tank 12 allows separation of the gas and the liquid withdrawn. The liquid level in this balloon is regulated by

a valve 7.

  The liquid product leaves the bottom of the first ripener

  by line 14 and is relaxed at the pressure of the second ripening-

  15 through a valve 9 before being introduced.

in said ripener.

  The ripening time of the product is regulated by

  mediaire a level control system of the liquid product 16 contained in the ripener by actuating the valve 17 which allows the withdrawal of the pitch. This is cooled by means of a heat exchanger 4 and then stored under

  liquid form in a tray or in granular form

  the. Adjustment of the temperature difference between the ripening zone and the ripener head is ensured by adjusting the flow of reflux liquid from the reflux tank 18

  this by means of an action-temperature control system

  19. The level of liquid in the

  reflux is regulated by a valve 20.

  The light distillates produced during ripening are withdrawn via line 21 cooled by the heat exchanger 3 and condensed in the reflux tank 18 allowing

  separation of the gas and the liquid withdrawn.

  Light distillates from both ripeners can be extracted or distilled

  in order to prepare pure substances such as naphtha

  lene, styrene, 1- and 2-methylnaphthalene, after

  distillation to incorporate the cuts obtained in the

rants or in diesel fuel.

  The following examples are intended to illustrate the invention

  without being limiting in nature.

EXAMPLES 1 TO 7

  A petroleum residue from the steam cracking of a naphtha fraction is used. This residue has the following characteristics: Density at 250C Viscosity at 200C Insoluble in hexane Conradson index Flammability AFNOR Sulfur Distillation ASTM PI

1.0516

  234 cS 7.2% weight 8.7 960C 0.15% weight 128C

% 205 C

% 223 C

% 253 C

% 292 C

70% 321 C

  The steam cracking residue is subjected to a treatment

  two-stage thermal circuit according to the present invention.

  Table 1 summarizes the conditions and results of the

  treatment carried out on the previous residue with a view to

  binding of binders for anodes used in the manufacture of aluminum.

  The resins indicated in the table have the characteristics

  The resins are soluble in quinoline and insoluble in toluene, the resins are soluble in toluene but insoluble in heptane, the resins are soluble in quinoline and insoluble in toluene, the resins are soluble in toluene but insoluble in heptane,

  the resins' are soluble in heptane.

24 8 1310

TABLE I

Example n

Conditionalities

MIRISSEUR 1

  TC background 380 380 370 380 380 380 380 hTi 0C 80 90 90 40 67 40 70 P (bar) 7.8 7.2 6.9 7.7 6.8 5.7 7 t1 (H) 3H20 1H40 3H07 4H10 2 H 4H10H% distillate 19.7 21 20 22.3 19.6 40.2 9.3

MURISSEUR 2

  T C mer 348 340 350 339 353 358 360

T2 C 60 35 45 30 50 48 50

  P -. Atmospheric t2 (min) 41 21 43 69 44 lH30 39% distillate 38.1 36.3 37.9 37.4 36.7 20.4 39.2% pitch 39.7 38.8 38.3 38.8 39 , 0 37.1 38.2 pitch analysis

KS C 85 80 83 90 90 90 92

  Conradson% 50.1 44.0 45.0 -48.5 48.3 49.8 50.1

  O + 5% /, 23.8 20.1 23.2 27.6 20.7 27.5 23.0

(resins x <0.5)

  Y% 22.0 23.4 19.5 23.7 25.3 20.4 22.4

  v 1 54.2 56.5 57.3 48.7 54.0 51.1 54.6

52 15 _ _

! ............... _......

i

2 4 8 13 1 0

EXAMPLES 8 TO 10

  The steam cracking residue of Example 1 is used in

  view of obtaining pitches for coatings.

  Table II summarizes the operating and indi-

  than the characteristics of the pitches obtained.

TABLE II

Examples

terms

MURISSEUR 1

  T C bottom 1 0C P (bar) t (II)% distillate

MURISSEUR 2

T C background Pressure

T2 0C

  t2 (min)% distillate% pitch pitch analysis KS C Conradson% a. + [3% (resins ix <0.5) y% 7.7

3 h 20

, 3, 0 33.6, 5 28.0 22.2 7.5

3 H 18

  18.9 atmospheric 43.8 32.0 54.2 29.4, 1, 5 6.2 3 Il 56, 3, 0 47.9 28.0 17.8 a 54.2 4 9.8 EXAMPLES 11l A The steam cracking residue of Example 1 was mixed with coal tar having the following characteristics Density at 20 C 1.15 g / cm3 Viscosity at 50 ° C 86.5 Cst

* C 8.25

  Flammability C 100 Pour Point C - 3 Conradson (%) 21.8 Sulfur% 0.52 Asphaltenes% 17.5 Water% 0.7 Distillation ASTM PI 100

% 205

10% 242

% 325

  % Cracking The mixture, consisting of 80% steam cracking residue and% coal tar, is subjected to

  two-stage ripening according to the present invention.

  Table III below summarizes the conditions and

  results of treatments performed on the mixture.

  The pitches obtained can be used as

  gnation given the low viscosities at 200 C.

248 1310

TABLE III

Examples

terms

MURISSEUR 1

  T C bottom AT (c) t1 (H) Pressure (bar)% distillate

MURISSEUR 2

* T C background

AT (C)

  t2 (minutes) Pressure% distillate Yield in pitch% Characteristics of pitch

KS- (C)

  % Conradson a + - (%) Density at 20 C (g / cm3) at Viscosities (cP) at 200 C II

3 H 26

  6.7 19.7 33.9 43.5 49.6, 7 1.21 1 Il 10 6.1 19.6 atmospheric 44.1 48.3 21.6 1.20

204; 116

3 H 18

6.3 19.1 34.1 43.8 48.3 1.21 221-

EXAMPLE 14

  The oil residue used comes from cracking

  afraid of cutting gas oil. This residue has the following characteristics: Density 1.15 Viscosity at 980C 100 cP Conradson% 19.6 Resins a + 1.8% wt Asphaltenes 22% wt This residue is subjected to a heat treatment in two

  stages according to the present invention.

  Table IV summarizes the treatment conditions and indicates the characteristics of the pitch obtained. This pitch can be used for example as a carbon electrode binder in

the aluminum industry.

TABLE IV

  T bottom C 380 a T C 50 l ripener Pressure (bar) 5 Time (H) 2% distilled wt 23 T bottom C 360

T C 40

2nd ripener Atm. Pressure

  time (minutes) 10% distilled% wt 19

KS 85

  Conradson% 52.6 pitch 14%% wt 28 pitch 14% +% wt 28 Density at 20 C 1, 23

EXAMPLE 15

  From the pitch of Example 6, a coke paste consisting of the addition of a Sherwood coal paste known to provide a poor quality steel coke (because of the high content of volatile matter of the coal) is prepared. Tymawr coal paste known to provide good quality steel coke (because of the low

volatile matter of coal).

  The final coke paste is coked in the laboratory in an electric oven with a capacity of 7 kg. Carbonization is carried out at the rate of 31C per minute up to

  a maximum temperature of 1.0000C. At this temperature,

  eradicates a ripening of one hour. The temperature in the center of

  the sample is then about 9001C.

  The coke is subjected to "extinction" by watering. After quenching, the coke is subjected to the MICUM test as defined by the standard AFNOR NF M 03020 incorporated in the ISO R 556 1967 standard which makes it possible to determine the M10 index, which is the percentage of coke passing through the 10 mm sieve. The lower the M1O index of the steel coke, the better

abrasion resistance.

  The compositions of the coke pastes and the results of

  MICUM test are shown in Table 5.

  M 10 Coke Paste Composition a) Sherwood / tymawr 3/7 (Reference) 10.4 b) Sherwood / tymawr 1 / i 11.7 c) Sherwood / tymawr 1/1 + 7.5% pitch 8.7 Si the results obtained from pasta b and c are compared, it is noted that the incorporation of 7.5% of prepared pitch

  according to the invention substantially improves the quality of iron

of the coke obtained.

EXAMPLE 16

COMPARATIVE TRIALS

  To illustrate the thermal stability of pitches,

  know were carried out on pitches obtained from a

  steam cracking of a fraction of light distillates (35-180), one from the one-stage process as described in 4i, 8 1 -,

  patent application 7700103 and the other obtained from the

of this application.

  The treatment conditions were chosen so as to prepare a pitch having a substantially identical softening point KS and a percentage of Conradson carbon.

  A 50g sample of pitch is placed in a carton.

  aluminum key 3 cm in diameter. This is then placed in an oven swept by a stream of air, for 3 days at 220 ° C. The stability of pitches is appreciated by the variation of the viscosity before and after the test as well as by the percentage of weight loss. The operating conditions and the results obtained on these two pitches that can be used for

  impregnation are shown in the table below.

  T C background 370 haT (C) 40 t 1 (h) 2 h 10 Pressure (bar) 6.6% distillate 20.4 T C bottom 406 360

AT (C) 30 25

  252nd ripener t2 (h) 5 h 08 1 h 18 Pressure (bar) 7.8 0.8% distillate 58 51.2 Yield% pitch 42 36.8

KS 85 86

  % Conradson 45.6 46.2 a + B% 39.4 23.3 Visco. 220 C (cP) 500 430 Visco. after stroke. at 220 ° C (cp) 2,800 Visco. after Visco. before% loss 13.3 12, 4- 4.3 1.6 It is found that the pitch prepared according to the invention is

  significantly more thermally stable than the pitch prepared

the previous process.

248131n

REVEW1DICATIONS

  1. Continuous method for pre ~ aration of pitches, characterized in that a steam cracking or thermal or catalytic cracking of petroleum fractions or fractions from said residues is subjected to a double thermal maturing at a temperature. avoiding carbonization of the resins and maintaining a significant temperature difference between the warmer part of the ripener and its colder part, in order to cause reflux of the light fractions into the body of the liquid mass while eliminating the

  undesirable effects, the first ripening taking place with or

  without catalyst under slight pressure, and the second one

  being carried out at a lower pressure and at a temperature lower than or equal to that

during the first maturation.

  2. Method according to claim 1, characterized in that the temperature of the first thermal milling is between 350 and 420 C and that the pressure can vary.

up to 15 bars.

  D 3. Method according to claim 1 or 2, characterized in that the temperature difference between the coldest zone and the hottest zone of the curing device is between 20 and 200 C, in the first device of ripening and between 10 and 150 C in the second device-of

ripening.

  4. Method according to any one of claims 1 to

  3, characterized in that the temperature of the second

  is between 300 and 380 C and that the pressure is

between 0 and 10 bar.

  5. A method according to any one of claims 1 to

  4, characterized in that the duration of treatment in each ripening device is defined by the formula: Volume of ripener 100 feed rate x 100 -% product removed 6. Process according to claim 5, characterized in that the residence time in the first ripening is between 10 minutes and 10 hours and the residence time in the second ripening: eur is between 5 minutes and

6 hours.

  7. Method according to any one of claims 1 to

  6, characterized in that the heavy hydrocarbon parts obtained as under

  steam cracking or thermal cracking

  petroleum hydrocarbons or their mixtures with other steam cracking or thermal or catalytic cracking residues or their fractions, coal tars, extracts obtained by solvent extraction,

petroleum distillates.

  8. Process according to any one of claims 1 to

  7, characterized in that a pitch originating from

  reactive distillation of a steam cracking residue.

  9. Braice obtained by the process as defined in one of

  any of claims 1 to 8, characterized in that

  it has a Kraemer Sarnow softening point of between 70 and 130, a density of between 1.10 and 1.35, a resin content e of between 5 and 40% and an index of

  Conradson greater than or equal to 40%.

  10. Device allowing the implementation of the method

  as defined in any one of claims 1 to 8,

  characterized in that it comprises two ripeners, the bottom of the first ripener receiving the feed preheated by heating means avoiding local overheating being connected to the second ripener, each of said ripeners being equipped (1) with a control system the level of the liquid product contained in said ripeners actuated by a valve located on the conduit leaving the bottom of each of the ripeners, (2) a device for drawing off the light distillates and the gases produced during ripening associated with a cooling device. cooling and a reflux flask for recycling in each of said ripeners and the

  regulation of the temperature difference between the ripening zone

  the ripener head by means of a valve located between the

reflux balloon and ripener.

  ) 11. Use of the pitch as defined in the claim

  9, for the elaboration of carbon electrodes or

  graphite, carbon-carbon composite materials,

  refractories, membranes or plastic coatings and

  for the manufacture of metallurgical coke.