FR2565124A1 - FLUIDIFYING ADDITIVE AND STABILIZER BASED ON SULFONE TAR AND SALIODY AND PROCESS FOR PREPARING THE SAME - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A FLUIDIZING AND STABILIZING ADDITIVE BASED ON SULPHONE TAR, IN WHICH THE SULPHONE AND SALIFIED TAR IS ALSO OXIDIZED, THE OXIDATION BEING EVIDENCE BY THE PRODUCTION OF SO DURING THE SULPHONATION REACTION. IT ALSO CONCERNS A PROCESS FOR THE PREPARATION OF THE ADDITIVE CONSISTING OF PUTTING THE TAR IN CONTACT WITH THE SO LIQUID OR GAS, THE TAR AND OR SO BEING PREFERABLY DISSOLVED IN A HALOGENOUS ORGANIC SOLVENT, THE SOLVENT IS RECOVERED AND THE SULFONE ADDITIVE IS SALIFIED. USE OF THIS ADDITIVE, ESPECIALLY FOR COAL SUSPENSIONS IN WATER.

Description

The present invention relates to a fluid additive

  difier and stabilizer and its method of preparation.

  In particular, the present invention relates to a fluidizing and stabilizing additive for suspensions of solid products in liquids and to a process for preparing same. Even more particularly, the present invention relates to a fluidizing and stabilizing additive for coal suspensions in liquids and its

process of preparation.

  In a more particular way, the present invention

  In a still more particular embodiment, the present invention relates to a fluidizing and stabilizing additive for coal suspensions in water.

  when coal is at a high concentration,

  at a concentration greater than 60% by weight, in particular 70 to 80% by weight or more,

and its method of preparation.

  In the description that follows, the authors of the

  The present invention refers to the case of coal suspensions in water, but of course, the additive of the present invention can be used regardless of the problems of fluidification and stabilization posed

  by the presence of suspended solids.

  The fluidifying and stabilizing additives for coal suspensions in water are known and consist of sulphonated, salified and neutralized goudrin compounds, these sulphonated compounds being obtained by the action of concentrated or fuming sulfuric acid on tars. The sulphonated additives of the known type have the disadvantage of containing

  large quantities of sulphatesalkyl sulphate or

  monium generated during the neutralization stage with alkali hydroxides or ammonia solution

  sulfuric acid containing sulphonated tar products.

  In order to sulphonate all the tar, it is necessary to use an excess of sulfuric acid and the alkali or ammonium sulphates remain in the sulphonated tar and neutralized once the water used to

  provide the neutralization agents has been eliminated.

  A second disadvantage presented by the additives

  of known type is due to the fact that in order to obtain better

  their viscosity characteristics, they must be condensed

  at least partly with formaldehyde and this

  requires an extra stage that is very expensive.

  Surprisingly, it has been discovered that these disadvantages of the known additives can be overcome and that a sulphonated & salified tar additive has better properties than

those of the known additives.

  A first subject of the present invention is therefore a fluidifying and stabilizing additive based on sulphonated and salified tar, characterized in that the sulphonated and salified tar is oxidized, the oxidation being demonstrated by the production of S02 during the stage. sulphonation, the amount of SO2 produced being between 2% and 60% by weight of the tar used,

  preferably between 10% and 35% by weight.

  In the description of the present invention,

  the term "tar" refers to coal tar such as that obtained in coke ovens, in particular by the distillation of coal at 1100 C or above, the fractions of which have a boiling point between 100 and 3500C, the residue of the distillation of coal tar at 3500C, in addition to the tars or tarry fractions obtained in the installations

oil treatment.

  Whatever the type of tar, it must contain at least a small percentage of compounds having more than two condensed aromatic rings. A second object of the present invention is the

  process for the preparation of the fluidifying additive and

  biliser previously described. The process according to the present invention consists in: 1) bringing about (preferably without removing the heat of reaction) the tar in contact with liquid or gaseous sulfuric anhydride in the presence of one or more solvents) of the tar chosen from the oraanic compounds halogenated, inert with respect to

  the sulfonation reaction, immiscible or

  readily miscible with water, preferably solvents chosen from those whose boiling point is between 30 and 130 C, and in particular chosen from

  Among carbon tetrachloride, tetrachlorethylene

lene, dichloretane.

  2) to terminate the reaction between SO3 and tar at a temperature between 80 C and 140 C,

  preferably between 90 and 120 C, by checking the

  SO 2 production until it reaches a value of between 2% and 60% by weight, relative to the weight of the tar used, preferably

between 10 and 35% by weight.

  3) neutralizing the sulphonated and oxidized tar solution with aqueous solutions of basic products, preferably sodium hydroxide or ammonia, until the pH reaches a value of 7 and

even a value of 10.

  4) Eliminate the solvent (s) of the tar by decanting

and / or by evaporation.

  5) recovering the aqueous solution containing the additive

sulphonated> salified and oxidized.

  6) to concentrate or possibly to dry the additive.

  Stages 3 and 4 can be reversed.

  According to a particular embodiment of the process of the present invention, the tar may first be dissolved in one or more of the solvents in question and

  liquid or gaseous sulfuric anhydride may be

  troduced in the tar solution as it is or after having been dissolved in one or more of the solvents mentioned, paying attention only to the compatibility of the O10 solvents with each other, that is to say

  do not give rise to chemical reactions.

  According to a second particular embodiment of the process of the present invention, the tar dissolved in one or more of the solvents mentioned or not dissolved can be poured into a solution of sulfur trioxide in one or more of the solvents in question, taking care of in the case where it is poured in the form of a solution, that the solvents are compatible and however pouring it very slowly in order to avoid a

reaction too violent.

  The present invention is illustrated by the descriptive and nonlimiting examples hereinafter. The tar used in all the tests of the examples is a tar coming from coke ovens and having a density of 1.1577

  g / cm and a viscosity of 83.81 cSt at 40 ° C.

Example 1

  The equipment for the reaction consists of a 500 cc four-necked flask equipped with a mechanical stirrer

  with polytetrafluoroethylene blades, a thermoset

  meter, of a refrigerant with spherical balls cooled by

water and a dropping funnel.

  In the flask, 44 g of tar diluted with 100 cm3 of tetrachlorethylene are introduced, while in the dropping funnel a solution of 53 g of

  SO3 liquid in 100 cc of tetrachlorethylene.

  The sulfur trioxide solution is introduced into the laboratory flask within about 2 hours, the flask being continuously cooled to maintain its internal temperature between 10 and 15oC. Once the addition of SO3 is complete, the internal temperature is allowed to rise to 20-25 ° C., then about 1 hour later, the reaction mixture is heated to reflux temperature (about 120 ° C.) and

  maintain at this temperature for 1 hour.

  The reaction mixture is then cooled, diluted with water and the crude product is transferred.

  the resulting reaction in a beaker where it is neutral.

  triturated to pH 7 with aqueous sodium hydroxide solution; then the whole of the mass is distilled under atmospheric pressure in order to recover the solvent in the form of a water / tetrachlorethylene azeotropic mixture. 975 g of an aqueous solution free of solid material are obtained and 196 cm3 of solvent are recovered from

cm put at the beginning.

  Na2SO4 content 1.70% Dry active substance 107 g Sodium sulphate formed 16.6 g Amount of SO2 formed 2.1 g

Example 2

  We use the same equipment as that of

Example 1

  43 g of tar diluted with 100 cm 3 of carbon tetrachloride are introduced into the flask, while 51.7 g of SO 3 are introduced into the dropping funnel.

  diluted with 100 cc of carbon tetrachloride.

  The SO 3 solution is added over 2 hours, while cooling externally with water (internal temperature 15 ° C.), the reaction mixture is then left for 1 hour at room temperature and then refluxed. (about 80 C) for 2 hours. The reaction mass is cooled to room temperature, diluted with water, transferred to a beaker, washing the flask again with water, and then neutralized until the reaction is complete. a pH of 7. with an aqueous solution

of sodium hydroxide.

  The azeotropic mixture of carbon tetrachloride-water is separated by distillation in the form of an overhead fraction and an aqueous solution is obtained

of 1176 g as residue.

  Content of Na2SO4 1.7% Dry active part 94.5g Sodium sulphate formed 20 g Quantity of formed SO2 2.6g -Examples 3 to 17

  Examples 3 to 17 are carried out under conditions

  identical experimental conditions with regard to temperature, tar and SO3 dilution in the

  solvent, and the duration of the addition of SO3 to the tar.

  The same equipment as in Example 1 is used. Procedure: in the flask, the diluted tar is introduced with 100 cm 3 of tetrachlorethylene (TCE) and inside the ampoule, SO 3 is introduced.

3. 3

diluted with another 100 cc of TCE.

  The addition of the SO3 solution is carried out in the space of about 90 minutes while cooling

  externally the laboratory flask with water (temporarily

internal temperature 10-15 C).

  The reaction mass is maintained at the temperature

  The reaction mass is cooled to room temperature, diluted with water and then neutralized with a solution. The reaction mixture is cooled to room temperature (approximately 20-30 ° C.) for 1 hour and then refluxed for 1 hour at 120 ° C. aqueous sodium hydroxide. We separate the most

  much of the solvent as the lower phase

  in the final reaction mixture after neutralization and this solvent is partially recovered as an azeotropic mixture with water. The total amount of solvent recovered is about 96 to 97%. The results concerning these tests are reported

in table 1.

  The evacuated gases (most often constituted by SO 2 with traces of SO 3) were analyzed in all the examples by absorbing them in a trap containing a

  aqueous solution of titrated NaOH downstream of the refrigerant.

Example 18

  The same equipment as described is used

in example 1.

  The laboratory flask is loaded with 80 g of SO3

diluted with 100 cm3 of TCE.

  Fill the bulb with 44 g of tar

diluted with TCE.

  The tar solution is added to the SO 3 solution in about 50 minutes, while the temperature of the reaction mixture rises gradually from 22 to 72 ° C; the reaction mass is then heated to 120 ° C., the temperature being maintained at this value for 1 hour. Most of the solvent is then decanted at 80 C. The flask is then immersed

in a thermostats bath. 140 C.

  Most of the solvent is recovered within 80 minutes (recovery about 98%). The reaction mixture is neutralized while still hot (80-85 ° C) until pH 7 is obtained with 15% sodium hydroxide solution and then diluted with

some water.

8-

  795 g of aqueous solution are obtained.

  Sodium sulphate content 2.9% Dry active part 92.9g Sodium sulphate 23, lg SO2 produced during the reaction 13 g Organic sulfur 14.3g

Example 19

  The same equipment as in Example 1 is used. The flask is loaded with 44 g of diluted tar.

with 326 g of TCE.

  The valve bulb is charged with 81 g of liquid SO 3. The addition of the liquid SOO to the tar solution is carried out within 40 minutes without externally cooling the laboratory flask. (The temperature which is 23 at the beginning increases to a maximum value of 90 C and it is 65 C at the

end of the addition).

  The reaction mixture is heated to 120.degree.

  space of 15 minutes and is maintained at this temperature.

erased for 1 hour.

  The solvent is then decanted at about 90 ° C. (TCE recovered 274 g), the laboratory flask is then immersed in an oil bath thermostated at 132-134 ° C. in order to recover the solvent by distillation. By

  this second operation, the residual TCE is recovered.

  The residual mixture is neutralized at about 80-90 ° C. with an aqueous solution of NaOH until a pH of 7 is obtained. The weight of the aqueous terminal solution of sulphonated, oxidized and salified tar is

477 g.

  Na2SO4 content 6.8% Dry active portion 97.5g Sodium sulfate 32.4g SO2 produced 13.9g Organic sulfur 17, lg

Example 20

  The same equipment as in Example L is used. The laboratory balloon is loaded with 44 g of

Tar diluted with 327 g of TCE.

  The addition funnel is charged with 79 g of liquid SO3. The SO3 solution is added to the tar within 40 minutes without cooling the laboratory flask externally. (The indoor temperature which was 21 C at the beginning increases to a maximum value of

   C, then it is 65 C at the end of the addition of SO3).

  The reaction mixture is then heated to the boiling point of the TCE (about 120 ° C) in 15 minutes and then maintained at that temperature for 1 hour. Most of the solvent (270 g) is then separated by decantation to about C, the laboratory flask is then immersed in an oil bath thermostated at 140 C. The residual solvent is collected in the course of 2 hours. The solid residue inside the flask is neutralized with an aqueous sodium hydroxide solution until a pH of 7 is obtained. The weight of the aqueous terminal solution

is 474.4 g.

  Sodium sulphate content 7.4% Dry active part 93.9g Sodium sulphate 35.1 g SO2 produced during test 13.1g Organic sulfur 15.4g Comparative example N 1 The same equipment as described is used

in the example n l.

  Operating procedure 38.8 g of tar diluted with 200 cm 3 of tetrachlorethylene are introduced into the flask, while 43.8 g of liquid SO 3 are introduced into the dropping funnel. We introduce this SO3 in the space of about

  minutes in the cooled laboratory flask outside

  with running water to maintain constant

  the internal temperature is between 17 and 20 ° C. The mixture is then stirred for a further 4 hours while constantly maintaining the internal temperature at 17 ° C. The sulphonated tar mixture is then neutralized until a pH of 7 with a

  aqueous solution of sodium hydroxide.

  The solvent is then recovered by azeotropic distillation.

  897.3 g of aqueous solution are obtained.

  Sodium sulphate content 3.82% Dry active part 63.9 g Sodium sulphate 34.3 g S 2 product below the analytical limit Organic sulfur 9.2 g

  The product thus obtained does not have any

dispersant properties.

  Comparative Example N 2 The same equipment as that described in Example 1 is used, except that the laboratory flask has a 3O3

  capacity of 250 cm instead of 500 cm3.

  Operating procedure We introduce into the balloon 17 g

  of tar diluted with 50 cm3 of TCE.

  In the dropping funnel 31.8 g of

SO3 diluted with 50 cm3 of TCE.

  This SO3 is introduced into the laboratory balloon in about 135 minutes while cooling the flask externally with running water so

  to maintain the internal temperature between 16 and 18 C.

  The mixture is kept stirring for a further

  minutes always at a temperature of about 18 C.

  The reaction mixture is then neutralized with an aqueous solution of sodium hydroxide to

we have a pH of 7.

  787.4 g of aqueous salt solution are obtained

sodium sulphate tar.

  Sodium sulphate content 1.45% Dry active part 58.6 g Sodium sulphate 11.4 g S02 produced during the reaction below the analytical limit Organic sulfur 9.4 g

  The product thus obtained does not have any

dispersant properties.

  Measuring the viscosity of coal dispersions in water

  In order to evaluate the various samples of

  In addition to those having the structure described herein as well as those commercially available, viscosity measurements are carried out at different speed gradients using a "Haake RV12" rotary viscometer (trade mark) equipped with an MVI detector and a head of

measure M500.

  For this, 70 g of coal having a size of

  particles less than 60 mesh and a content of -

  humidity less than 0.5%, are weighed in a beaker cm and an aqueous mixture of the dispersant to be examined is added in order to have in all:% by weight of coal 29.5% by weight of water 0.5 % by weight of dispersant The products are mixed using an agitator comprising two metal whisks for 1 minute at

  650 rpm and for 2 minutes at 1200 rpm.

  The suspension thus obtained is introduced into the external measuring cylinder of the viscometer already maintained at a constant temperature of 20 ° C. and after a residence time of 15 minutes at 20 ° C., the values of shear forces (t) with various speed gradients. -1) (<) (from 3.8 to about 150 s) are measured. The experimental values thus obtained are calculated using the equation of power or Ostwald: = K.n

  valid for pseudoplastic behavior.

  For each series of experimental measurements t -, the values of K and n and the curve tcalc- * are calculated with the regression line. Moreover, for the last five values i tested (= 37, 60,, 120 and about 150 s), the values of the viscosity

  "asymptotic" qasympt are calculated by imposing the

  t-ô experimental values.

  The values obtained for certain samples by operating thus are the following: K dasympt (viscosity Typera of an asymptotic) dispersant n. Pa. S Pa.S "DAXAD 15" (product 0.91 0.83 0.58 commercial) Example 18 0.92 0.81 0.61 Example 11 0.87 1.05 0.57 Measurement of resistance to shear forces

  A sample of the dispersant according to the

  vention is compared with a sample of the trade

  (DAXAD 15, Grace Italy) according to the method described above.

  after under the heading "stability according to the effort

shearing ".

  In a 1-liter glass reactor having a flange having 10 cm high and 10 cm in diameter, 336 g of dry coal (moisture less than 0.5%) having a particle size of less than 60 mesh and a dispersant solution in water in order to have at the end the following loading:% by weight of coal 29.5% by weight of H2O 0.5% by weight of dispersant The mixture is stirred while the reactor is open to air with a whip stirrer for 2 minutes at 650 rpm, then during

at 1200 rpm.

  The flange is closed, a motor device equipped with a flywheel 2 cm in diameter is placed at a level of 200 ml and the mixture is kept under stirring at 200 rpm.

  minute for 24 hours. We stop the agitation

  positive motor is removed and the whole thing is abandoned

  for 3 days. At the end of this time, the beaker is

clinks and the suspension is paid.

  The results obtained are shown in the table below in which the asterisk symbols have the following meanings: = case in which all the suspension flows spontaneously = case in which with the aid of a glass rod or a similar way, we can easily thin

  again the residue remained at the bottom.

  * = case in which a compact deposit was formed at the bottom which was difficult to remove with the aid of a

spatula or similar means.

  Concentration Weight introduced, from the part of the active part of the Solution Aqueous aqueous solution Behavior to Additive Additive carbon Additive water flow

DAXAD (15) 336 24 120 10.0 E

Example 11 336 36.92 107.08 6.5 *

-rNt TABLE 1

  (M u4n Tests with different weight ratios S03 / tar% 0aD Weight Weight of LN Weight Weight Weight of the sulphate portionSulphideReport Example tar SO active dry sodium formed SO formed organicpuncal N og gg g S03 / tar

3 41 15 17 4818 412 13 514 0141

  i 113514 0141 4 41 5 26 5510 717 2i4 74 0163

40 3 31 62 6 715 217 815 077

6 40 3617 5315 812 219 717 0.92

  7 401 1 4507 7531 1418 312 10 6 1114

8 4012 515 8o018 1813 410 126 128

  9 40 12 6216 8915 19) 9 412 1513 1156

4066 4 909 2418 510 15 4 1166

11 41 7 69 5 971 25 4 5.8 1812 1T67

  12 43 75 98 7 2816 9tO 1619 1174 13 37 6918 8713 27> 7 11r2 1418 1189

  14 40 4 83I6 97 8 353 137 151 6 2.07

  327 89 930 507 13t7 1615 2172 16 26 81.6 74T6 53t7 1217 12 6 3 14 17 3016 10217 9310 7117 16f9 1616 3136

Claims (12)

  1. A fluidizing additive and stabilizer based on sulphonated and salified tar, characterized in that the sulphonated and salified tar is oxidized, the oxidation being evidenced by the production of SO2 during the sulphonation reaction, the amount of SO2 produced being between 2% and 60% by weight in relation to the tar weight.   2. Additive according to claim 1, characterized   rised by the fact that SO2 is produced in an amount of between 10% and 35% by weight relative to the weight tar.   3. Process for preparing the additive according to   the preceding claims, characterized in that   it consists in: a) slowly bringing the coal into contact with the liquid or gaseous sulfur trioxide in the presence of one or more tar solvents, chosen from halogenated organic compounds which are inert with respect to the reaction of sulphonation, immiscible or slightly miscible with water; (b) to terminate the reaction between SO3 and tar at a   temperature between 80 C and 140 C, preferably   between 90 C and 120 C, controlling the production   of S02 until the amount of S02 reaches   a value of between 2% and 60% by weight relative to the weight of the tar; c) neutralizing the solution of the sulphonated and oxidized tar with aqueous solutions of alkaline products;   (d) removing the solvent (s) from the tar by   tation and / or evaporation; e) recovering the aqueous solution containing the sulphonated, salified and oxidized dissolved additive; f) concentrating or possibly drying the additive;   since we can reverse stages (c) and (d).   4. The process according to claim 3, wherein   because solvents have points   boiling range between 30 and 130 C.   5. The method of claim 3, wherein   characterized by the fact that the solvents are chosen from carbon tetrachloride, tetrachlorethylene and dichloroethane.   6. The method of claim 3, wherein   the fact that S02 is produced in one   amount between 10% and 35% by weight at the weight of tar.   7. The method of claim 3, wherein   achieved by the fact that the neutralization is carried out   with sodium hydroxide solution.   8. The method of claim 3, wherein   achieved by the fact that the neutralization is carried out with an ammonia solution.   9. Process according to any one of the   3, 7 and 8, characterized in that the neutralization is carried out until the pH reaches 7.   10. The method of claim 9, wherein   achieved by the fact that the neutralization is carried out until the pH reaches 10.   11. The method of claim 3, wherein   tered by the fact that the tar is dissolved   lable in one or more of the solvents and that the sulfur trioxide is brought into contact with the tar by introducing it into the tar solution is such   either in solution in one or more of the solvents.   12. The method of claim 3, wherein   characterized by the fact that the tar is brought into contact with the sulfur trioxide by pouring the tar either as it is, or as a solution in one or more of the solvents, in a solution of sulfur trioxide in one or many of the solvents.