EP0330626A2 - Process for removing by evaporation discharge waters from oil crushers by using olive marc soaked with said waters in a plant - Google Patents

Abstract

The subject of the present invention is a process for eliminating the discharge water from oil mills, obtained by using, in a desiccation installation, spent olive marc soaked in said water, of the type in which the water is sprayed. vegetable water on the olive marc which is put in a hot air cyclone of a desiccation installation where the water evaporates and the solid parts in suspension are deposited on said olive marc which, successively , is again covered with vegetation water and reintroduced into the installation, and so on until all the water has evaporated; this process being characterized by the fact that the olive marc used to introduce, into the hot-air cyclone, the vegetation water which must be evaporated results in being spent marc, that is to say marc to which one has already removed the oily residues by degreasing.

Description

The subject of the present patent application for industrial invention is a process of elimination, by evaporation, of the residual vegetation water from the pressing of the olives, obtained by using, in a desiccation installation, spent and soaked olive marc of said waters.

It should be specified, in fact, that three different products result from the pressing process of the olives: olive oil, olive marc, made up of all the peelings (skin, pulp and pressed pits) as well as vegetation water which contains about 15% organic substances and 2% mineral substances.

This vegetable water, until a few years back, was discharged into the sewers or directly on the ground, while the oil was conveyed to the final work and the olive marc was conveyed to the factory where the oily residue was extracted , which was still there, to obtain olive oil. Currently, the practice of discharging vegetation water in this way has been lost. On the one hand, these waters contained an oily residue anyway which should be recovered and, on the other hand, the Merli Law of 1979 which considered very polluting the content of said vegetation water, prevented its discharge by dispersion on the ground, in rivers or in sewers.

Following this legislative intervention, we therefore began to study processes for the elimination of vegetable water capable of completely eliminating said water while respecting the standards in force, and also to look for the possibility of recovering the oily residue contained therein.

One of the processes more followed in recent years is that of eliminating vegetation water by evaporation, this by means of a complex and costly desiccation installation which must be carried out next to the oil mills.

In this type of installation, the water was evaporated after having sprinkled it on the virgin olive marc, that is to say what remains after the first pressing of the olives; Indeed, the marc soaked, was introduced into a hot air cyclone, inside which was determined the evaporation of water and therefore the deposition of substances contained therein on the marc which successively left this same installation.

This olive marc was soaked once again with vegetable water and reintroduced into the cyclone until the evaporation of this second quantity of water which also deposited its organic and mineral components on the marc.

This operational cycle naturally had to be repeated until all the water had evaporated; that is to say that the virgin olive marc constituted the vehicle by means of which all the water of vegetation could be introduced into the desiccation installation, until obtaining its total elimination.

At the end of this cycle, olive marc was obtained which was particularly rich in gummy, resinous and similar components; components that are originally suspended in vegetation water. This olive marc was then sent to the factory to obtain olive marc oil.

From this perspective, we understand that, by means of this kind of process, we obtain the dispersion, in a completely harmless manner, of the vegetation waters as well as the recovery of all the oily components that the said waters originally suspended. and which are then deposited on the marc leaving the drying installation.

This process also has strong drawbacks, both functional and economic; if we consider the functional aspect of this elimination system, it must be highlighted that, following repeated passages of virgin olive marc, which always becomes richer in gummy, resinous or similar components, in the desiccation installation determines the production of smelly exhalations, consequence of the successive and violent reheating of these organic components present in the marc of olives.

Naturally, these exhalations are dispersed in the atmosphere by the chimneys of the installation from which the water vapor also leaves, which causes an extremely unpleasant odor in the surroundings; that is to say that in fact with this process we eliminate the pollution of the soil but we pollute the air; which may be less harmful but certainly much more tedious for all those who live or happen to pass in the vicinity of a desiccation installation of this type.

From an economic point of view, it must be said above all that this type of equipment involves high installation and management costs; costs which are usually out of the question for small oil mills which produce a small annual quantity of oil and which therefore cannot count on a large turnover.

It should also be noted, on the other hand, that even in the hypothesis that a large oil mill could buy a similar installation, there would in any case be the problem of purchasing the fuel necessary to supply the furnace warming of the air to be sent to the aforementioned cyclone and where concretely the warming and evaporation of the vegetation water takes place. Using traditional fuels for this purpose can be considered, from an economic point of view, totally unsuitable and therefore, usually, we prefer to buy spent marc from the factory, that is to say that which is already deprived of all oily components and duly selected to separate the component derived from the pits of the olives, the only one that is capable of working advantageously as a fuel, the component derived from the peelings and the pulp which, on the contrary, is used as animal fodder.

The oil mill is therefore forced, in this hypothesis, to sell virgin olive marc to the factory, a factory from which it will have to buy spent pomace to supply its own desiccation installations.

On the other hand, it should also be specified that the oil mill would not even have the advantage of separating the combustible component of its virgin olive marc from the non-combustible component on its own, as long as, if it is fair to say that in such a way he could produce the fuel necessary for his desiccation plants on his own, it must also be said that he could not sell to the factory the private marc of the kernel component since this component would be unsuitable to support the process of degreasing by means of the gasoline which is carried out in the said marc factories and which, effectively, cannot be carried out without the presence, inside the virgin olive marc, of this component of the pits which functions, practically, as an essential drainage element. In order to obviate these drawbacks, the process of eliminating vegetation water according to the invention has been studied and developed.

On the basis of the invention in question, in fact, the process of evaporation of the discharge water from the oil mills should be carried out directly at the marc factory, using, as a vehicle to introduce vegetable water in the hot air cyclone, spent olive oil and no longer virgin.

The fact of carrying out the process of evaporation at the marc factory already represents, from an economic point of view, an extremely important innovation since, in this case, the marc factory could remove oil mills, in addition to the marc of virgin olives, the vegetation waters which it would then ensure the elimination. All this would involve, on the one hand, avoiding the oil mills, especially the smaller ones, the high costs necessary for the construction of desiccation installations as well as the relative management costs (especially those in fuel); on the other hand, this would entail optimizing the use of the drying plants of the marc plants with which the latter must in any case be equipped to accomplish the process of extracting the marc oil, thereby obtaining better amortization.

In addition it must also be taken into account that the marc factories would thus offer the oil mills the possibility of having the vegetable water removed with the virgin olive marc, which constitutes a very important advantage for the negotiation of the purchase of the marc olives from the marc factory which is able to offer this ancillary service compared to those who cannot provide it; in other words, it can surely be said that the marc factory which is also able to offer the service of removing the vegetation water could hope to obtain a sort of monopoly on the purchase of marc the oil mills , especially in those not still equipped to dispose of landfill on their own and who do not wish to provide an autonomous installation. A further advantage of the process according to the invention also derives, as regards the functional, from the introduction of what must be considered the most important and characterizing innovation over the entire operational sequence which leads to the evaporation of the waters. vegetation.

As already stated, this innovation consists in using exhausted marc inside the hot air evaporation cyclone, available in large quantities at the marc factory, instead of virgin marc.

Indeed, the spent marc, having elapsed at the end of the degreasing process of the virgin marc necessary to obtain the marc oil, no longer has gummy components, resins or the like; this means that, in spite of the repeated passages in the hot air cyclone and the successive deposits of subsequent quantities of gums and resins which are carried out on the marc during the continuous phases of evaporation of the water which it conducts in the installation, the exhausted marc never risks producing, during repeated and violent reheating, the highly smelly exhalations characteristic of virgin marc.

In conclusion, by using spent marc, we obtain that the quantities of gums and resins present in the vegetation waters are deposited, during the successive phases of evaporation, on an inert basis, ending, in fact, by adding up one on top of the other; while if we use virgin marc, which is rich in gums and resins, following successive and subsequent deposits, we actually get to "saturate" this marc, with the consequence of provoking, precisely, the production of aforementioned smelly exhalations during repeated warmings.

It is also obvious that the factory of olive marc, when the dispersion of the landfills is completed, will work the spent marc which was used as a vehicle to drive the water to evaporation, by removing from this last, following the traditional degreasing processes, all the oily components which are deposited during the successive phases of evaporation.

As a result, new spent marc will be obtained which may be partially saved for future landfill disposal processes and may be partially used during a successive phase of work.

This subsequent operational phase consists in centrifuging the various components of the spent marc to obtain, as already explained, animal fodder and fuel for the desiccation installation in question, for the management of which, therefore, the factory marc will never have a problem given the abundance of marc available to use for this purpose.

It should be noted that, according to the process in question, it was also provided that the vegetation water could be treated with products to prevent fermentation, such as for example Na2CO3 or NaHCO3 before being introduced into the hot air cyclone with the spent marc.

The purpose of this operation is to block the fermentation of resinous, gummy and similar components suspended in said waters; Obtaining this result in fact means ensuring remarkable practical advantages: firstly, it means definitively averting the smallest possibility, which remains completely theoretical, of the production of smelly exhalations during the heating of water and spent marc in the cyclone with hot air, possibility which concretely results already eliminated, as already said, since one uses spent marc and therefore without active mucilage.

Secondly, this way of operating also makes it possible to obtain a considerable advantage with regard to the prospect of the final work of the marc which has already been extracted, after repeated passages in the cyclone of the desiccation installation in question; indeed, as soon as the fermentation of the mucilaginous components of the waters which soak the marc has already been blocked, this marc presents itself at the final work rich in no longer active substances.

Consequently, the oil which will be extracted therefrom will no longer have to be worked with caustic soda as is currently done to block the fermentation of gummy and resinous residues for the simple reason that in the oil extracted from said marc which has collected deposits of water treated with products against fermentation there are no more active residues.

We can therefore say that by adding products to the vegetation against fermentation, we simplify the refining phase of marc oil, because we can avoid this clarification and neutralization operation that we must currently perform by means caustic soda.

It should be noted that to obtain the cessation of the fermentation of vegetable water using the above-mentioned chemicals, the above-mentioned water must first be heated.

In fact, before treating the above-mentioned waters in this way, they must be brought to a temperature of around 70 °, which can be easily done, without further loss of energy, by using the boiling vapors which come out of the drying installation chimneys.

This way of operating brings further economic and functional advantages as long as one obtains on the one hand to cool the boiling steam before releasing it into the air and on the other to send in the hot air cyclone already warmed up vegetation water.

We therefore understand why we can consider it easier and economical for the desiccation installation to bring the said water to evaporation temperature, while only having to make up a temperature difference of about 50 ° (that is to say a initial temperature of approximately 50 ° / 60 ° to that of evaporation of 100 °) and no longer a difference of 80 ° / 90 ° or more (i.e. initial ambient temperature at 100 ° of the evaporation temperature).

Of course, in the field of this invention, an identical process of elimination of landfill waters can be carried out by using, instead of the spent olive marc considered in all of its components, only the individual components of the said olive marc, that is to say: or only the powder of the pits or only the peelings.

Claims (3)

1) The process of elimination, by evaporation, of the discharge water from oil mills, obtained by using, in a desiccation installation, spent olive marc soaked in said water, of the type in which water is sprayed vegetation on the marc to be introduced into the hot air cyclone of a desiccation installation where the water evaporates and the solid parts in suspension are deposited on the abovementioned marc; this marc being again sprinkled with vegetation water and reintroduced into the installation, and so on until the water has completely evaporated, being characterized by the fact that the olive marc used to introduce the vegetation water which must be evaporated in the hot air cyclone turns out to be spent marc, ie marc which has already undergone the process of extracting oily residues by means of degreasing. 2) The process of elimination, by evaporation, of the discharge water from oil mills, obtained by using, in a desiccation installation, spent olive marc soaked in said water, of the type in which water is sprayed of vegetation on marc to be introduced into the hot air cyclone of a desiccation installation where the water evaporates and the solid parts in suspension are deposited on the abovementioned marc; this marc being again sprinkled with water from vegetation and reintroduced into the installation, and so on until the water has completely evaporated, characterized in that the said vegetation water, before being sprinkled on the grounds, is heated to a temperature about 70 ° and added with anti-fermentation products such as Na2CO3, NaHCO3 or Na2SO2O5. 3) process of elimination, by evaporation, of the discharge waters of the oil mills, obtained by using, in a drying installation, spent olive marc soaked in said water, according to the preceding claims, characterized in that during its progress, instead of using spent olive marc with all its components, one can also use, with the same methods and the same results, individual components of this spent olive marc and more precisely: or only the powder of the pits or only the peelings.