EP0225199B1 - Process for the homogenization of a mixture of aqueous residual liquids with liquid fuels or solids - Google Patents

Abstract

The invention relates to a method which makes it possible to produce homogeneous mixtures of industrial wastes such as polluted waters, hydrocarbon wastes and various coal grades, as well as combustible industrial wastes. An essential feature is that the homogeneous mixtures produced in accordance with this invention are stable, and lend themselves to being pumped and injected. According to the invention, this method consists in forming during a first stage a stable emulsion of oily combustible material in water and during a second stage, in mixing this emulsion with a solid or liquid combustible material.

Description

The present invention relates to a process for producing homogeneous stable pumpable and injectable mixtures of industrial residues such as polluted water, hydrocarbon waste and coal or combustible industrial waste.

Thanks to this process, it is possible to obtain a relatively thick liquid fuel, the calorific value of which is between 2,500 and 5,000 kgcal / kg, this product being able to be stored, pumped and injected for example into the nozzles of fireplaces or boilers.

There are currently methods for suspending carbon in ordinary water or in polluted water. However, it is very difficult to add hydrocarbons to it because the latter adsorb on the grains of coal and give sludge floating in the original water. For the same reason, it is impossible to grind coal in water and in the presence of hydrocarbons.

It is also known for example from European patent EP 0 051 053 to produce an emulsion comprising water, a hydrocarbon and a fuel which is stable but this emulsion is made stable by the addition of alcohol. The addition of alcohol makes it possible to obtain a microemulsion in which the oil droplets in suspension have diameters less than 100 microns.

The use of alcohol makes the mixture dangerous, which means that special storage arrangements have to be made. The alcohols used generally have flash points of between 11 and 25 _° C which means that the storage constraints which for flash points below 55 _° C and especially below 21 ° C require compliance with the storage constraints. provision of fire zones, explosion-proof motors ...

The present invention makes it possible to avoid these drawbacks by proposing to produce homogeneous mixtures of water, hydrocarbons, coal or industrial waste and characterized in that a stable emulsion of hydrocarbons is first produced in water via a nonionic surfactant having an HLB between 15 and 20 and that in a second step, this emulsion is mixed with either coal or combustible industrial waste, and this in the presence of a colloid.

The expression H.L.B. stands for Hydrophily-Lipophily Balance, which translates to Hydrophilic Lipophilic Balance. A compound having an H.L.B. high is hydrophilic and promotes the formation of fine oil droplets in water.

Such surfactants at H.L.B. high may be non-ionic polyoxyethylene derivatives including H.LB. is close to 17, these agents will be used in proportions of 1 to 3 per 1,000 of the water + hydrocarbon mixture.

The use of a colloid means that no special storage rules have to be observed because their flash point is close to or greater than 100 _° C.

Preferably, this colloid will be added to the products to be emulsified in the proportion of 0.5 to 1%.

It is important that the emulsion produced in the first phase of the process is an emulsion of the hydrocarbon in water and not the reverse.

• - stabiliser l'émulsion,
• - éviter la décantation,
• - maintenir une pseudo-plasticité.

This colloid will have the following triple role:

• - stabilize the emulsion,
• - avoid settling,
• - maintain a pseudo-plasticity.

According to one aspect of the invention, the colloid will be a xanthan gum.

By pseudo-plasticity is meant that the liquid will become more fluid when agitated; this is important when the final product is intended to be stored in a tank then pumped and injected.

If heavy and thick hydrocarbons have to be emulsified, the aqueous emulsion can also be facilitated by adding light and fluid hydrocarbons acting as solvent or diluent.

It is also possible, in addition to the colloid, to add a silicate in a proportion of 0.5 to 1%. It has in fact been found, in many cases, that the silicate enhances the action of the colloid.

Once the stable aqueous emulsion has been obtained, a mixture of this emulsion and a solid or liquid fuel is produced in an appropriate stirring device of any known type. One can use for this a ground solid fuel or even in some cases only crushed, the grinding being done later. It is also possible to use a solid fuel, either pure or mixed with impurities.

It has been found that it is advantageous to obtain a good mixture to be used, for producing the emulsion of alkaline waters having a pH between 9 and 11 and on the other hand that if the final product has to stay longer than one week in a tank, it is more prudent to treat the colloid with a bactericide in order to avoid bio-degradation. When we use water polluted by phenol, we obtain this bactericidal effect which protects the colloid.

It is also possible, if it is necessary to emulsify heavy hydrocarbons, to mix them with light hydrocarbons.

• - les eaux polluées peuvent avoir été polluées par des hydrocarbures, des alcools, des phénols, des amines, des sels minéraux solubles, des matières organiques ou des matières végétales ou analogues;
• - l'hydrocarbure devant être émulsionné dans l'eau peut être: des boues d'hydrocarbures, des boues organiques, des graisses minérales organiques ou végétales, des goudrons, des boues de forage ou analogues;
• - les produits combustibles solides devant être ajoutés après émulsion peuvent être: des produits ou sous produits miniers, des schlamms, des fines de dépoussiérage, du charbon actif, du carbon-black, du coke de pétrole, du vapocrackeur, du goudron solidifié, des brais, des terres ou sables pollués, ou analogues.

For the implementation of the method according to the invention:

• - polluted waters may have been polluted by hydrocarbons, alcohols, phenols, amines, soluble mineral salts, organic matter or vegetable matter or the like;
• the hydrocarbon to be emulsified in water can be: hydrocarbon muds, organic muds, organic or vegetable mineral greases, tars, drilling muds or the like;
• - the solid combustible products to be added after emulsion can be: mining products or by-products, schlamms, dedusting fines, activated carbon, carbon-black, petroleum coke, vapocracker, solidified tar, pitches, polluted soil or sand, or the like.

It is also possible to add to the mixture according to the invention dispersing agents such as poly- naphthalenes sulfonates lignosulfonates or polyacrylates.

The invention will be better understood in the light of the examples below which are given without implied limitation.

Example 1

• 45% d'eau polluée par 5% de carbonate de sodium 20% d'huile minérale usée (huile de vidange)
• 35% de charbon Sud-Africain broyé, ayant un refus de 22% au tamis de 80 microns, et
• si on agite très violemment un tel mélange, on constate qu'il est impossible d'obtenir un mélange homogène, même en y ajoutant des agents tensio-actifs.

If a mixture is produced, in a known manner, comprising:

• 45% of water polluted by 5% of sodium carbonate 20% of used mineral oil (waste oil)
• 35% of crushed South African coal, having a 22% refusal using an 80 micron sieve, and
• if such a mixture is very violently agitated, it is found that it is impossible to obtain a homogeneous mixture, even by adding surfactants to it.

On the other hand, if at first, polluted water and mineral oil are mixed by adding 0.15% of an ethoxylated nonylphenol including H.L.B. is 17.1, a very fluid and very stable emulsion is obtained; if in a second step, the carbon is added thereto, the latter disperses very easily and very regularly in said emulsion and a homogeneous mixture is obtained free of lumps or agglomerates.

The mixture thus obtained is left to stand and after a few hours there is a slight settling of particles greater than 100 microns.

If a dispersing agent such as xanthan gum in the proportion of 0.15 per 1,000 is added to the previously obtained homogeneous mixture, there is no more settling, the particles remaining very mobile in the mass.

The homogeneous final mixture thus obtained from industrial waste and lean coal can be stored in tanks, then pumped and injected into heating body nozzles.

Example 2

It is generally difficult and dangerous to dry grind coals so that it is preferred to grind them in the presence of water.

However, if coal is ground in the presence of water and then an attempt is made to incorporate this ground coal into hydrocarbons, it is not possible to obtain a homogeneous product.

Using the three products of Example 1 but in which the coal is not finely ground (which is difficult and dangerous), but simply crushed, the procedure is as follows:

• - 0,500 kg d'eau polluée par 5% de NA2C03
• - 0,200 kg d'huile de vidange,
• - 0,300 kg de boues de charbon Sud-Africain concassé.

A mixture of:

• - 0.500 kg of water polluted by 5% of NA2C03
• - 0.200 kg of drain oil,
• - 0.300 kg of crushed South African coal sludge.

The whole is placed in a laboratory mill consisting of a jar loaded with grinding agents. After half an hour of operation of the mill, there is a thick mud of coal and oil in the presence of water forming a well separated phase. Even by extending the grinding for several hours, it is impossible to obtain a homogeneous mixture.

On the other hand the test is conclusive if one operates in the following way:

0.500 kg of polluted water and 0.200 kg of used mineral oil are mixed at high speed in the presence of 2 ml of surfactant (ethoxylated nonylphenol of which the H.L.B. is 17.1).

0.300 kg of crushed South African coal is added and the whole is immediately ground. After half an hour, a very fluid homogeneous liquid having 0.15 poise of viscosity is removed.

Example 3

• 50% d'eau polluée par 0,5% de phénol
• 40% d'huile minérale usagée
• 10% de coke de pétrole broyé

By proceeding according to the present invention, it is possible to homogenize the following mixture:

• 50% water polluted by 0.5% phenol
• 40% used mineral oil
• 10% ground petroleum coke

For this, it is necessary to emulsify first the polluted water and the huit by adding the surfactant nonyl-phenol-ethoxylated but also by adding 1% of sodium carbonate because to obtain suspensions of petroleum coke in water, it is essential to add a dispersing agent. Once the emulsion has been produced, it is sufficient to pour petroleum coke.

As in the case of Examples 1 and 2, such a mixture, owing to its homogeneity and its stability, can be stored in a tank then pumped and injected into furnace nozzles and boilers so that a fuel which can be used is obtained. from industrial residues and pollution products.

Example 4

• 40% d'eau polluée par 0,5% de phénol
• 15% de fuel domestique
• 45% de charbon Sud-Africain broyé comme indiqué
• à l'exemple 1,

on obtient un produit se présentant en deux phases:

• - une phase boueuse comprenant le charbon et le fuel domestique,
• - une phase aqueuse.

If the following mixture is vigorously kneaded:

• 40% water polluted by 0.5% phenol
• 15% domestic fuel
• 45% of South African coal ground as indicated
• in example 1,

a product is obtained which is presented in two phases:

• - a muddy phase comprising coal and domestic fuel,
• - an aqueous phase.

On the other hand, if the fuel and the polluted water are vigorously kneaded in the presence of 0.20% nonyl-phenol-ethoxylate (HLB = 17.1) and 0.05% of polycolloid, an emulsion is obtained in which one pours then the ground coal. It disperses easily to give a homogeneous liquid usable as fuel.

Example 5

This example illustrates the use of the process according to the invention for extracting the heavy fuel oil incorporated in sand, that is to say for recovering this heavy fuel oil which is incorporated in a combustible mixture which can be used industrially while cleaning the sand.

• soit 100 gr. de sable de rivière pollué par du fuel lourd
• n^o 2 dans la proportion 70% de sable, 30% de fuel lourd.

The example is given with river sand, but is also applicable to polluted "black tide" type marine sand:

• or 100 gr. river sand polluted by heavy fuel oil
• ^No. 2 in the proportion 70% sand, 30% of heavy fuel oil.

The following emulsion is prepared: 80 gr. of water + 20 gr. of White Spirit, shaking the mixture vigorously in the presence of 0.2 gr. ethoxylated nonylphenol.

A very vigorous mixing of this emulsion and the polluted sand makes it possible to release the sand from the fuel. We thus obtain a water phase, White Spirit, fuel at the bottom of which the sand has settled.

Since the operation has been carried out in an aqueous emulsion, it is possible to wash the sand with clean water, which can be reincorporated into the process.

This process makes it possible to work at ordinary temperature while avoiding the use of pure solvents.

• - des eaux polluées comprenant: des hydrocarbures, des alcools, des phénols, des amines, des sels minéraux solubles des matières organiques ou végétales ou analogues;
• - des hydrocarbures liquides, des boues d'hydrocarbures (type boues huileuses), des boues organiques animales ou végétales, des graisses minérales organiques ou végétales, des goudrons des boues de forage ou analogues;
• - des produits ou sous-produits miniers tels que "schlamms", fines de dépoussiérage, de charbon actif, boues de noir de carbone (carbon black), du coke de pétrole, du vapocrackeur, du goudron solidifié, des brais, des terres ou sables polluées ou analogues.

The process according to the present invention can be used to make mixtures with:

• - polluted waters comprising: hydrocarbons, alcohols, phenols, amines, soluble mineral salts of organic or vegetable matter or the like;
• - liquid hydrocarbons, hydrocarbon muds (oily muds type), organic animal or vegetable muds, organic or vegetable mineral fats, tar from drilling muds or the like;
• - mining products or by-products such as "schlamms", dedusting fines, activated carbon, carbon black sludge, petroleum coke, vapocracker, solidified tar, pitches, earth or polluted sands or the like.

The purpose of the dispersants mentioned above is to act on the zeta potential of the particles in order to promote their dispersion. It is possible to use: alkali carbonates or silicates; polynaphthalenes sulfonates; lignosulfonates; polyacrylates.

Claims (10)

1. A process for the production of homogeneous mixtures of water, hydrocarbons, coal or industrial waste, characterised in that, in a first stage, a stable emulsion of hydrocarbons in water is produced using a non-ionic surface-active agent having an H.L.B of between 15 and 20 and, in a second stage, either coal or combustible industrial waste is mixed with this emulsion in the presence of a colloid.

2. A process according to claim 1, in which the colloid is a xanthan gum.

3. A process according to claims 1 and 2, in which the water used for producing the emulsion is an alkaline aqueous solution of which the pH is between 9 and 11.

4. A process according to claims 1 and 3, in which sodium carbonate or sodium silicate is used to improve the emulsion.

5. A process according to claims 1 to 4, in which a simply crushed solid fuel is added to the emulsion, grinding being carried out subsequently (of the coal for example).

6. A process according to any one of claims 1 to 5, in which the polluted water may have been polluted by hydrocarbons, alcohols, phenols, amines, soluble mineral salts, organic substances or vegetable substances or the like.

7. A process according to any one of claims 1 to 6, in which the hydrocarbon to be emulsified in water can be: hydrocarbon mud, organic mud, organic mineral or vegetable fats, tars, drilling mud or the like.

8. A process according to claim 1, in which the liquid fuels to be added after emulsion can be those described in claim 7.

9. A process according to claim 1, in which the solid fuels to be added after emulsion can be: mining products or by-products, sludge, dedusted fines, activated carbon, carbon black, oil coke, steam- cracking products, solidified tar, pitch, polluted earth or sand or the like.

10. A process according to claims 8 and 9, in which dispersing agents such as polynaphtha- lenesulphonates, lignosulphonates or polyacrylates can be used.