RU2749371C1 - Method for separating fatty mass from wastewater and preparing it for biodiesel production - Google Patents

Abstract

FIELD: waste disposal.SUBSTANCE: invention relates to the field of disposal of liquid industrial waste containing high concentrations of vegetable or animal fats with their subsequent preparation for the production of biodiesel, and can be used in municipal services and for industrial enterprises, in the industrial wastewater of which there is a high content of vegetable or animal fats, unacceptable for subsequent biological treatment of wastewater or its release into the city sewer network or water bodies. The method of separating fatty mass from wastewater and its preparation for the production of biodiesel includes the flow of wastewater after mechanical treatment to the flotation unit with the formation of flotation sludge, the flow of flotation sludge into the storage tank - homogenizer, which also receives the fatty mass from the shop or on-site grease catcher, the flow of fat mass into the macerator, the flow of homogeneous fat mass from the macerator into the melting pipe, in which the fat mass is heated and fed further to the tricanter, in which the fat mass is divided into three components - centrate, sediment, fat, the separated fat phase is fed into the separator, then, optionally, the fat is fed to the fat mass processing unit and entering the biodiesel production unit, where alcohol, catalyst and sorbent are additionally dosed, biodiesel and glycerin are formed at the outlet of the unit.EFFECT: invention improves the environmental safety of production, to reduce the operating costs of enterprises for the utilization of fatty mass, to transform production waste into a secondary material resource (SMR) - a resource for the production of biodiesel.5 cl, 1 dwg

Description

The claimed method relates to the field of disposal of liquid industrial waste containing high concentrations of vegetable or animal fats with their subsequent preparation for biodiesel production.

Industrial wastewater from enterprises of various industries contains high concentrations of fats (animal or vegetable origin - oils), for example:

- wastewater from tanneries contains up to 1700 mg / l (average value 550 mg / l);

- wastewater from fish processing enterprises contains up to 1940 mg / l, in the total effluent 1800 mg / l;

- wastewater from the oil and fat industry contains 1000 mg / l in the total effluent;

- waste water from enterprises of the perfumery and cosmetic industry contains 775 mg / l;

- waste water from meat industry enterprises contains up to 1000 mg / l

The permissible concentration of fats for biological wastewater treatment, depending on the technological scheme, is 50-100 mg / l, therefore, these substances must be separated from wastewater, as a rule, this valuable product is taken to landfills as a production waste. On a national scale, the amount of fats as industrial waste is at least 1600 t / day. (584,000 tons / year).

Today, there are technologies that make it possible to process fats of plant and animal origin into biodiesel fuel, however, in order to consider production waste - fatty mass separated from wastewater as BMP for biodiesel fuel production, it is necessary to develop a technology for preparing the separated fatty mass for further transesterification.

Known traditional methods of processing pure vegetable oils or animal fats into esters of fatty acids and low molecular weight alcohols by carrying out a transesterification reaction with methanol or ethanol, while the reaction is carried out using an alkaline catalyst [Biodiesel production from oils and fats with high free fatty acids. / M. Canakci, J.V. Gerpen. // Trans ASAE. - 2001 - Vol. 44, No. 6. - P. 1429-1436., Patent RU 2632671, publ. 10/09/2017; patent RU 2538647, publ. 01/10/2015; patent RU 2404230, publ. 20.11.2010]. However, these methods involve the use of a pure product and cannot be applied directly to production waste. Thus, both vegetable and animal fats contained in industrial wastewater must be recovered and treated as BMP. The most important indicator of fatty waste is the acid number of fat, which determines the concentration of free fatty acids. It is known that in order to achieve a high yield of transesterification products, the maximum concentration of fatty acids in the raw material should not exceed 0.5-1% wt., The increased content of fatty acids promotes saponification of fats, as a result of which not only the catalyst is neutralized, but also the subsequent separation of products is significantly hampered transesterification reactions.

The prior art discloses a method for reducing the acid number of fat by neutralizing it with the required amount of NaOH. Neutralization was carried out at a temperature of 50 ° C for 15 minutes with constant stirring. After neutralization, the fat containing soaps and alkali residues was sent for washing with a 10% solution of salt and water in compliance with the ratio of fat to solution 1: 1. In this case, washing with saline was carried out 1 time, with water 2 times (water temperature 90-95 ° C) for a total duration of 90 minutes. The washing solutions were separated from the fat by settling. The remaining water was removed from the separated fat by short-term evaporation while stirring it. The purified fat was sent for transesterification with the addition of 25% ethanol 96%, catalyst - 0.75% dry alkali NaOH with a temperature maintenance of 60 ° C for 60 minutes. (Method of producing biodiesel from fat-containing fish waste by the method of transesterification reaction) Chan Nyung Thi, M.D. Mukatova, N.A. Kirichko ISSN 2073-5529. Bulletin of ASTU (fisheries) 2011. No. 1).

This method makes it possible to obtain biodiesel from the fat of the internal organs of the crust. It was found that biodiesel from fish oil has a high flash point - 120 ° C, low viscosity - 5.0 mm2 / s, which meets the requirements of GOST R 52368-2005 “Diesel fuel EURO. Technical conditions ".

The disadvantage of this method is the lack of devices that provide the possibility of separating the fat-containing mass from wastewater. Also, this method involves the neutralization of fatty acids and their removal from the composition of the fat-containing mass, which reduces the possible amount of biodiesel produced.

A known method of processing fat-containing plant waste (vegetable oils), carrying out a one-stage operation, including combined acid-catalyzed reactions of esterification of free fatty acids and transesterification of triglycerides with ethanol to obtain ethyl esters of fatty acids. The reactions are carried out at a temperature of 70-75 ° C and using sulfuric acid as a catalyst, its concentration is set in the range of 1.5-2% wt., With a mass ratio of triglycerides: alcohol from 1: 6 to 1:10 and with a water content in ethanol up to 3.8% wt. The content of free fatty acids in raw materials can range from 0 to 40% wt. The esterification and transesterification reactions are carried out in one apparatus and in one stage. A distinctive feature of the proposed process is its carrying out in homogenized systems, using as a homogenizer mixtures of esters of alcohols and fatty acids, which contain at least 50% of polyunsaturated hydrocarbon radicals with two or more double bonds (patent RU 2720410 "Method for producing complex esters of fatty acids and ethanol from fat-containing waste ”, published on 29.04.2020).

This invention provides for the processing of fat-containing waste with an admixture of free fatty acids, when combining the reaction of esterification and transesterification and obtaining in one stage esters of fatty acids and ethanol with a yield of at least 95% and a reaction time of up to 12 hours instead of 40-96 hours, however, to achieve the claimed effect, the analogue under consideration has a disadvantage, which can be considered the absence of devices that provide the possibility of separating a fat-containing mass from wastewater and preparing it for the combined reaction of esterification and transesterification.

A known method for producing biodiesel fuel. The method provides for pretreatment of mesopelagic fish to obtain lipids, transesterification of the obtained lipids and separation of the resulting biodiesel fuel. The caught fish is mechanically formed into biomass. Then fish oil is obtained by pressing, which is subjected to enzymatic hydrolysis in the presence of a protease. The resulting product is filtered to separate the lipids. Transesterification of the obtained lipids is carried out with a dehydrated solution of potassium or sodium methoxide in methanol (patent RU 2404230 "Method for producing biodiesel fuel", published on November 20, 2010).

The invention allows to obtain biodiesel fuel, which can be used in vehicles in winter conditions.

The disadvantage of this analogue, which does not allow it to be used in the claimed method, is that the enzymes quickly lose their activity, it is advisable to use enzymes immobilized on the carrier, but they show less activity compared to pure enzymes, it is also necessary to select enzyme. Also, this method does not take into account the processes of preparation and extraction of fats from industrial wastewater.

A known method of processing fat mass in order to obtain technical fat ("Utilization of fat-containing wastewater sludge from the meat-packing plant" RKZ-Tavr "K.O. Okovitaya, international scientific journal" Innovative Science "No. 5/2016 ISSN 2410-6070), adopted by the applicant for a prototype on the greatest number of similar essential features aimed at treating fatty mass separated from industrial wastewater: using devices to implement the processes of heating fatty mass, separating solids, and separation.

According to this method, it is envisaged to prepare the captured fat from the wastewater of the meat processing plant for processing into a marketable product, for this, the fat captured in the grease traps enters the decanter settler, where further settling and separation of fat from waste water and suspensions takes place. After the decanter settler, the floating fat sludge is sent to the fat collection tank, after which it is sent to a continuously operating installation for fat melting. The mass is heated to 70-80 ° C and then pumped into the pressure tank using a vacuum pump at a residual pressure of 90 kPa. After filling the pressure tank, the valve is opened, and the fat mass flows by gravity into the dirt separator, which is used as a fat sump OZH-1.6. A filter is mounted inside the dirt separator. The mass in the dirt separator is heated by supplying steam to the jacket of the apparatus for 2-3 hours.After this time, a three-way valve is opened and the fat mass at a temperature of 60-70 ° C is sent to the OGSh-321K-01 centrifuge with a pump for further separation of solids ... The purified fat-water emulsion from the centrifuge is fed by gravity into the AVZH-245 machine, where the final heat treatment with live steam supplied under a pressure of 0.2-0.3 MPa takes place, then the fat is purified on separators. The refined fat is pumped into collectors, from where it is packed into barrels or pumped into a tanker truck for bulk transportation. The fat obtained from the fat mass of industrial effluents has a dark color, a pungent specific odor, a high acid number, and belongs to grade III technical fat.

The processing of the obtained fat-containing sediments in a dirt separator, centrifuge, separator, machine for melting fat AVZH-245, allows you to get technical fat and green production.

Common to the claimed and known methods are the following: heating the fat mass, separating solids, cleaning in a separator.

The disadvantage of the known method adopted for the prototype, which does not allow achieving the proposed technical solution, is the absence of devices aimed at reducing the concentration of free fatty acids in the fat mass and the possibility of realizing the complete preparation of the fat mass as BMP for producing biodiesel fuel.

The task to be solved by the claimed technical solution is to increase the environmental safety of production, reduce the operating costs of enterprises for the utilization of fatty mass, transform the waste into a resource for the production of biodiesel.

This problem is solved due to the fact that the claimed method of separating fat from wastewater and its preparation for the production of biodiesel is carried out using a device for concentrating fats from wastewater (grease traps, flotation devices), an equalizer, a macerator, a melting tube, a tricanter, a separator, a reagent treatment unit fat mass (with the content of free fatty acids in the fat mass from 1% to 40% wt.), a biodiesel production unit, a unit for preparation and dosing of alcohol, an alkaline reagent, an acid reagent, pipelines and equipment for feeding the fat mass to structures.

When preparing a fat-containing runoff for the production of biodiesel at a concentration of fatty acids in the fat mass from 1% to 40% wt. a unit for reagent treatment of fatty mass can be used, including the esterification of free fatty acids with a solution of sulfuric acid.

When preparing a fat-containing effluent for the production of biodiesel at a fatty acid concentration of 1% to 10% wt. can be used for the separation of fatty acids from fat by the extraction method.

When preparing a fat-containing effluent for the production of biodiesel in the presence of a unit for the separation of fatty acids from fat by the extraction method, an acid esterification unit of the separated fatty acids and an alkaline transesterification unit of neutral fat can be used.

When preparing a fat-containing effluent for the production of biodiesel in the presence of a unit for the separation of fatty acids from fat by the extraction method, alkaline transesterification of neutral fat and a unit for obtaining detergents from the separated fatty acids can be used.

The conducted patent research showed that neither in the patent nor in the scientific and technical literature there is no information about the technical solution proposed in the claims, which gives grounds to assert that the proposed technical solution meets the criterion of patentability "novelty".

Comparative analysis of devices that are used in known technical solutions, including the prototype, showed essential features that distinguish the proposed solution.

The advantages that are achieved indicate that the tasks that are being solved are performed at an inventive level, since they do not obviously follow from the solutions known in the art and therefore meet the patentability criterion "inventive step".

The claimed method for preparing the fat mass of industrial wastewater is illustrated by a drawing, where in FIG. 1 shows a technological scheme for the preparation of industrial wastewater fat mass in accordance with the claimed method.

The designations of the positions in the drawings are as follows:

1 - reagent flotation device (flotation unit);

2 - sediment accumulator;

2.1 - stirrer;

2.2 - pump for supplying fat waste for processing;

3 - shop and on-site grease trap;

4 - macerator;

5 - melting pipe;

6 - steam generator;

7 - tricanter;

7.1 - cake container;

7.2 - pump for supplying fat drain to the separator;

8 - separator;

8.1 - pipeline for supplying wastewater with a low content of fatty acids;

8.2 - pipeline for supplying waste water with a high content of fatty acids;

9 - unit for reagent treatment of fatty mass with a content of free fatty acids (when the content of free fatty acids in fatty mass is from 1% to 40% by weight);

10 - reagent preparation unit;

11 - biodiesel production unit;

12 - unit for dosing methanol / ethanol;

13 - catalyst dosing unit;

14 - unit for dosing sorbent;

15 - biological treatment facilities.

The method is implemented as follows: industrial wastewater after mechanical treatment is fed to the flotation unit (reagent flotation device) (1), where fatty mass, suspended solids, organic impurities, etc. are separated, forming flotation sludge with a moisture content of 97-96%. Clarified water is supplied for further biological treatment to biological treatment facilities (15), and flotation sludge enters the storage tank - homogenizer (sediment accumulator) (2), which also receives fat mass from the shop or on-site grease catcher (grease trap) (3), as well as other fat streams from production, in the accumulator-homogenizer the concentration of fat mass is averaged from the reservoir of the accumulator-homogenizer, fat mass with a moisture content of 97-96% enters the macerator (4), in which coarse impurities are crushed, from the macerator the homogeneous fat mass enters the melting pipe (5 ), in which, due to direct injection of water vapor, from the installed steam generator (6), the fat mass is heated to 90 ° C and enters the tricanter (7), in which the fat mass is divided into three constituent parts - centrate, sediment, fat, at In this case, the centrate enters the head of industrial wastewater treatment plants, the sludge is discharged into containers for cake (7.1 ) for further disposal at industrial waste landfills.

The separated fat phase is pumped (7.2) into the separator (8), in which the fat is separated from suspended particles and dehydrated to a moisture content of no more than 1%. If the fat mass contains no more than 1 wt% free fatty acids, it is fed through the pipeline (8.1) to the biodiesel production unit (11), where methanol / ethanol is additionally dosed, i.e. alcohol (12), caustic potassium catalyst (13) and sorbent (14), biodiesel is formed at the outlet of the unit, as well as glycerin, which is further utilized.

In the presence of free fatty acids in the fat separated from the separator from 1% to 40% wt., The fat, before entering the biodiesel production unit, enters through the pipeline (8.2) to the fat mass processing unit (9) containing free fatty acids, in which there is a decrease in the concentration of free fatty acids in one of the following ways:

- when the concentration of fatty acids in the fat mass is from 1% to 40% wt. a unit for reagent treatment of fatty mass (10) can be used, including the esterification of free fatty acids with a solution of sulfuric acid;

- at a concentration of fatty acids from 1% to 10% wt. a unit for separating fatty acids from fat by the extraction method (10) can be used, while after extraction, units can be used: acid esterification of isolated fatty acids, alkaline transesterification of neutral fat, alkaline transesterification of neutral fat, obtaining detergents from isolated fatty acids.

Claims (5)

1. A method of separating fat mass from wastewater and its preparation for the production of biodiesel, providing for the flow of waste water after mechanical treatment to the flotation unit with the formation of flotation sludge, the flow of flotation sludge into the storage tank - homogenizer, which also receives the fat mass from the shop or on-site grease catcher, the flow of fat mass into the macerator, the flow of homogeneous fat mass from the macerator into the melting pipe, in which the fat mass is heated and fed further into the tricanter, in which the fat mass is divided into three components - centrate, sediment, fat, the separated fat phase is fed into the separator, then, optionally, the fat is fed to a fat mass processing unit and entering the biodiesel production unit, where alcohol, catalyst and sorbent are additionally dosed, biodiesel and glycerin are formed at the outlet of the unit. 2. The method according to claim 1, characterized in that when the concentration of fatty acids in the fat mass is from 1 to 40 wt%, a unit for reagent treatment of fat mass is used, including the esterification of free fatty acids with a solution of sulfuric acid. 3. The method according to claim 1, characterized in that when the concentration of fatty acids in the fat mass is from 1 to 10 wt%, the unit for reagent treatment of the fat mass is a unit for separating fatty acids from fat by the extraction method. 4. The method according to claim 3, characterized in that an acid esterification unit of the isolated fatty acids and an alkaline transesterification unit of neutral fat are used. 5. The method according to claim 3, characterized in that a unit for alkaline transesterification of neutral fat and a unit for obtaining detergents from the separated fatty acids are used.

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