ITLE20120007A1 - PROCESS INNOVATION FOR THE TREATMENT OF OLIVE WORKING RESIDUES. - Google Patents

Description

DESCRIPTION of industrial invention having as title:

Process innovation for the treatment of processing residues

some olives

TEXT OF THE DESCRIPTION

The present invention refers to a process innovation for treating olive processing residues, in order to treat the processing by-product, the pomace, and the residue from the transformation process, the vegetation water.

The transformation of olives into oil is carried out through the following phases:

â € ¢ defoliation;

â € ¢ washing of the olives;

â € ¢ pressing or milling, to crush the pulp of the olives and release the juices; the product of this operation is the oil paste;

â € ¢ kneading, consisting in the slow and continuous mixing of the dough;

â € ¢ squeezing;

â € ¢ Extraction, from the paste by centrifugation or pressing, of a must based on oil and water;

â € ¢ centrifugation of the must and separation of the oil from the residual liquid.

The residual liquid at the end of the process constitutes the vegetation water, composed of the water present in the fruit, any water added during the processing phase, as well as the organic and inorganic substances soluble in it. The solid residue from the pressing or centrifugation of the pasta is the pomace.

The method of the present invention carries out the purification of the vegetation waters and the recovery of virgin pomace using the thermal energy produced by a conventional thermoelectric plant. This power plant can also be fed from the olive tree pruning waste.

A thermoelectric power plant is an industrial plant that, by burning fossil or renewable fuels, powers one or more heat exchangers designed to evaporate a working fluid under pressure, be it water or organic fluid, to be expanded in one or more turbines coupled to an electric generator. .

The method object of the invention employs a boiler fed with vegetable biomass, coupled to a diathermic oil exchanger. The diathermic oil transfers combustion energy to the electric generator, inside which an organic fluid carries out a thermodynamic cycle which is completed with the expansion in the turbine and therefore with the production of electricity.

The vegetation water purification process is divided into three phases:

A) Evaporation of the aqueous component and concentration of the organic component.

B) Catalytic oxidation of the condensate.

C) Biological oxidation with activated sludge.

The evaporation and concentration phase A) creates a concentration of the vegetation water by evaporating part of the water contained. In fact, the vegetation water has a dry matter content of about 5% and can be concentrated by evaporation in traditional evaporators, up to a concentration of dry content (TS) of about 25%, beyond which it is started to dryers.

The evaporation and concentration process is divided into two stages:

A1) Evaporation of water

A2) Concentration of the organic component.

Unit A1 consists of an evaporator with forced circulation of the solution to be treated, suitable for the concentration of vegetation water, which uses hot water for condensation of the organic fluid in the Electric Generator as a heat source for the evaporation of the water present. in the emulsion. Evaporation takes place by boiling under vacuum, at a temperature of 60-65 ° C in a container maintained at an absolute pressure of 0.3 bar and the latent boiling heat is provided by the water in the cooling circuit. of the Electric Generator, water at a temperature between 75 and 90 ° C. The ratio between the evaporated water flow and the heating water flow is 1/40 - 1/45. Steam condensation takes place in an exchanger in contact with tower water or directly by passing through unit heaters.

From the evaporator, the concentrated solution up to about 25% of dry matter is transferred to a scraped type concentrator (A2 unit) which completes the process up to a concentration of 50% of dry matter. The compound is fluid and pumpable. The heating of the concentrated solution is always obtained with hot water at 75-90 ° C coming from the Electric Generator. Steam condensation takes place in an exchanger in contact with tower water or directly by passing through unit heaters.

The concentrated compound has a calorific value of 13-15 MJ / kg, therefore a good fuel. The compound is pumped to the boiler where it is thermo-enhanced in co-combustion with the biomass.

Any organic and inorganic substances, initially dissolved or suspended in the vegetation water, which by entrainment or evaporation flow with the steam and are not condensed, are continuously sucked and conveyed to the thermoelectric plant, where they are mixed with the air combustion agents are incinerated. The diffuse emission of aromatic or potentially harmful substances is therefore canceled.

The condensate produced in phase A), although deprived of the organic component, contains not negligible quantities of phenols. The concentration of these phenols is on average 1000 mg / l which corresponds to an oxygen demand (COD), necessary for their neutralization, of 7500 mg / l. Due to their biotoxic nature, said concentration of phenols prevents the direct treatment of the condensate in a biological activated sludge plant. Hence the need to provide for the pre-treatment of the condensate in a catalytic oxidation plant B).

The catalytic oxidation of phenols B) transforms the phenols present in oxidized species, which are non-bio-toxic and easy to oxidize by biological means. The reaction takes place in a reactor at a pressure of 12 bar and a temperature of 110-150 ° C. The reactor pressurization is obtained by injecting compressed air. The condensate is heated by heat exchange with diathermic oil leaving the Electric Generator. The temperature of the diathermic oil used varies from 140 to 160 ° C for an average heat input of 200MJ per ton of condensate to be treated. The catalyst used is copper sulphate.

The oxidized effluent is cooled to 30-40 ° C by adiabatic expansion in a vessel kept under vacuum and subsequently sent to a selective ion exchanger to remove the catalyst. The catalyst, after being regenerated, is recirculated at the head of the process.

Phase B) of catalytic oxidation of phenols involves in sequence:

â € ¢ the dosage of a solution containing the catalyst,

â € ¢ preheating of the condensed catalyst mixture in countercurrent with the oxidized flow leaving the reactor,

â € ¢ heating to 110-150 ° C in a condensate-diathermic oil exchanger,

â € ¢ catalytic oxidation under pressure in a reactor equipped with an agitator,

â € ¢ the cooling and expansion of the oxidized mixture,

â € ¢ Recovery of the catalyst.

The condensate at the outlet has a concentration close to 1mg / l of phenols with a COD of about 4500mg / l.

Phase C) of biological oxidation completes the oxidation, with activated sludge, of the organic substances present in the condensate. The process allows the reduction of the COD in input of 4500mg / l up to the value of 100 mg / l for discharging the efflux into surface waters or for irrigating energy crops, which supply fuel to the thermoelectric plant.

The concentration of nitrogen and phosphorus in the condensate affluent to the biological oxidation system is not sufficient for the proliferation of bacterial flora and therefore the two elements are added at the head of the process.

The biological oxidation of the condensate takes place in a tank with suspended biomass when the condensate is completely mixed with mud. The mixture is oxygenated by insufflation of air at low pressure. The activated sludge is subsequently separated from the condensate with a system of submerged membranes and started again in the oxidation tank. The excess sludge, about 1 kg every 5 tons of treated condensate, is subjected to thickening and then sent to the boiler feeding system to be thermo valorised in co-combustion with the woody biomass.

The purification process evolves in the following successive phases:

â € ¢ collection of condensate in the accumulation and equalization tank,

â € ¢ automatic balancing of nitrogen and phosphorus with pre-dosed products,

â € ¢ Biological oxidation with suspended biomass with complete mixing with low sludge load with air insufflation system,

â € ¢ separation and clarification of the condensate with immersed flat membranes, with a permeate extraction circuit and recirculation of the concentrate at the top of the oxidation tank, â € ¢ thickening of the excess sludge and sending to the thermal plant, after chemical conditioning.

The biological oxidation phase completes the purification treatment of the vegetation waters. The set of three purification phases has as its by-products the organic compound concentrated from the evaporation plant and the excess sludge from the biological oxidation plant, which are collected and added to the woody biomass feeding to the thermoelectric plant.

The virgin pomace, a solid by-product from the pressing of the must, has a water content such as to inhibit any non-assisted combustion process. The purpose of the present invention is to exploit the thermal energy made available in the thermoelectric power plant to dry the pomace and then extract the pits from it, i.e. the fragments of the endocarp of the olive (or commonly the shell of the seed), which it represents an excellent renewable energy source to be used for heating residential homes, and to enhance the waste given by the dust (what remains after separation from the core) in the plant itself.

The pomace treatment is divided into two phases

D) Drying of the pomace.

E) Screening.

The drying phase D) removes part of the water present in the pomace. The incoming pomace has an average humidity of 50%. The purpose of the drying phase is to reduce the concentration to 15-30%. The drying takes place under vacuum in a container maintained at an absolute pressure of 0.3 bar. The reactor consists of a cylindrical body with a horizontal axis with a scraper agitator that mixes the material during the drying phase.

Heating is carried out with diathermic oil from the thermoelectric plant. The temperature of the inlet diathermic oil varies from 140 to 160 ° C, the energy requirement varies, according to the residual humidity in the pomace, from 800 to 1100 MJ per ton of pomace treated.

The vapors developed are extracted from the vacuum system, through a separator cyclone, towards a condenser in which they condense. Condensation takes place with tower water or with water-air exchangers. The condensate has an average COD of 2000 mg / l due to the presence of phenols in solution, therefore it cannot be disposed of as such. The condensate is mixed with the effluent of phase A) of evaporation of the vegetation water to be subjected to treatments B) and C) of catalytic and biological oxidation.

Phase E) consists in the separation of the kernel from the powder, by means of vibro-screening. The dust represents the underscreen of operation E). In spite of the calorific value, the size of the particulate matter does not make it a good commercial fuel. Therefore it is intended for thermal valorisation in the thermoelectric power plant in co-combustion with woody biomass. The hazelnut is instead subjected to bagging and marketing.

As for the treatment of vegetation water, any organic and inorganic substances, which flow with the steam and are not condensed, are continuously sucked and conveyed to the thermoelectric plant, where mixed with the combustion air they are waste-to-energy.

The description should, as far as possible:

a) specify the field of the technique to which the invention refers;

b) indicate the state of the pre-existing technique, as far as the inventor knows, which is useful for understanding the invention and carrying out the research, possibly providing references to specific documents;

c) expose the invention in such a way that the technical problem and the proposed solution can be understood;

d) briefly describe any drawings;

e) describe in detail at least one embodiment of the invention, providing appropriate examples and referring to the drawings, where these are present;

explicitly indicate, if this is not already obvious from the description or the nature of the invention, the way in which the invention can be used in industry.

Claims (2)

CLAIMS 1) Process for the treatment of Vegetation Waters, olive processing residue, consisting of a phase (Al) of Evaporation of the aqueous component of the Vegetation Waters, a phase (A2) of Concentration of the residual organic component of phase (Al) , a phase (B) of catalytic oxidation for the purification of the steam produced in phases (Al) and (A2), a phase (C) of biological oxidation with activated sludge of the condensate produced in phase (B). This procedure is characterized by the fact that: a) phase (Al) exploits the excess thermal energy of the generator group of a thermoelectric plant, in the form of hot water at 75-90 ° C, to evaporate the aqueous component contained in the vegetation waters under vacuum. b) phase (A2) exploits excess thermal energy from the generator group of a thermoelectric plant, in the form of hot water, to concentrate, up to 25% of dry matter, the residual evaporation of phase (Al). The concentrate is used as a fuel for the thermal power plant. c) a suction system is created for non-condensable substances and any odorous substances produced during phases (A1) and (A2), these substances are destined for waste-to-energy in the boiler of the thermoelectric plant. d) phase (B) carries out a catalytic oxidation under pressure of the condensed vapor produced in phases (Al) and (A2), using copper sulphate as catalyst and pressurizing the oxidation reactor with compressed air. e) phase (B) uses the diathermic oil at low temperature (140-160 ° C) leaving the generator group of the thermoelectric plant to preheat the condensed steam. 2) Procedure for the treatment of virgin olive pomace, residue from the processing of olives, characterized by the fact that: a) the low enthalpy thermal energy of a thermoelectric power plant is exploited, in the form of diathermic oil at 140-160 ° C, to evaporate the water contained in the virgin olive pomace under vacuum. b) a suction system is created for non-condensable substances and any odorous substances produced during the process, these substances are destined for waste-to-energy in the boiler of the thermoelectric plant.