RU2259874C2 - Sorbent for removal of oil and petroleum products and method of making it from buckwheat husk - Google Patents

Abstract

FIELD: removal of oil and petroleum products.

SUBSTANCE: proposed sorbent is organic matrix of multi-size porous structure at size of pores from 2 to 35 mcm with mineral potassium-containing component distributed in it at weight ratio to carbon in matrix 1: (16-20). Sorbent is produced at temperature of 460-700°C in drum-type, shaft of chamber furnace at atmospheric pressure in plasma of high-frequency discharge of reduced pressure, in plasma of high-frequency of arc discharge of atmospheric pressure. Buckwheat husk is used as starting raw material.

EFFECT: enhanced efficiency.

5 cl, 2 dwg, 2 tbl

Description

The invention relates to the field of environmental protection and relates to the production of sorbents from plant materials used for cleaning water bodies, industrial wastes from oil and oil products.

The use of environmentally friendly natural raw materials for the purification of industrial and domestic waters, the purification of water bodies is one of the main areas of research conducted in the field of environmental protection. These types of raw materials include agricultural products, in particular crop products. For example, it is known to use as such raw materials the seeds or skin of beans, alfalfa seeds, clover (RF patents No. 2110481, С 02 F 1/28, 1998, No. 2129096, С 02 F 1/28, 1999), which are used for cleaning industrial and domestic effluents from metal salts, in particular chromium. As a sorbent for removing oils from water, carbonized walnut shells are used (US Patent No. 3992291, 01 D 23/24, 1976), cotton waste from cotton production is used to clean the water surface from oil (USSR, AS No. 1430355 , C 02 F 1 / 28,1994), untreated husk of buckwheat grains (RF Patent No. 2114064, C 02 F 1/28, 1998), carbonized husk of buckwheat grains (RF Patent No. 2031849, C 02 F 1/28, 1995), and carbonized husk of rice grains is used to purify water from oil pollution (RF Patent No. 2036843, С 02 F 1/28, 1995).

To expand the assortment of sorbents based on plant materials and to create a unified sorbent with increased sorption efficiency, a new sorbent is proposed, which is a product of buckwheat husk processing and is an organic matrix of a multidimensional porous structure with a pore size of 2 to 35 μm with a potassium-containing mineral component distributed in it with a weight the ratio of potassium-containing mineral component to carbon, equal to 1: 16-20. Preferred properties of the sorbent include the following range of pore size distribution of the sorbent according to their dimension: 2-20 microns - 63-66%, 20-30 microns - 26-37%, 30-35 microns - 2-8%.

Table 1
The size distribution of the sorbent of the sorbent GS Pore sizes, microns Pore distribution range,% 2-20 63-66 20-30 26-37 30-35 2-8

Buckwheat husks are used as plant materials. The above signs of the sorbent are created upon receipt of the sorbent by heat treatment of buckwheat husk at a temperature of 460-700 ° C. The heat treatment process can take place in this temperature regime in a drum, shaft, chamber furnace at atmospheric pressure, in a plasma of a high-frequency or arc discharge at atmospheric pressure, or in a plasma of a high-frequency discharge at a pressure below atmospheric.

The main advantage of the new sorbent is its increased sorption capacity, which is achieved due to the formation of an organomineral product in which potassium acts as a mineral component. The weight ratio of the mineral potassium-containing component to carbon is 1: 16-20. It is the combination of the sorption activity of the potassium component distributed in the organic matrix that determines the increased sorption activity of the sorbent, which acquires a multidimensional porous structure with pore sizes from 2 to 35 μm. The presence of potassium groups in the sorbent is confirmed by x-ray studies (Figure 1).

Radiographs of sorbents obtained by the thermal method (HS _T ) and in high-frequency plasma of low pressure (HS _PD ) show that the main component of the sorbent is potassium. The peak of the roentgenogram corresponds to it with a maximum area of 19261. The content of the remaining elements is insignificant, therefore, they can be considered as impurities, to a lesser extent determining the properties of the sorbent. On the roentgenogram, for example, the sorbent of the modification of GS _T , the lines of the elements Ca, Al, P, Cu are visible. The corresponding areas on the spectrogram are equal: for Ca - 3969, P - 2108, Cu - 1738. Al - 612. X-ray diffraction patterns of sorbents obtained in an arc plasma (HS _D ) and in high-frequency plasma of atmospheric pressure (HS _AD ) practically do not differ from roentgenograms of sorbents GS _T and GS _PD, respectively.

The multi-porosity of the structure of the sorbent (Figure 2) is an essential feature, providing increased sorption activity. This is because the pores of the sorbent, depending on their size, play a different role in the retention of contaminants or participate in the retention of the adsorbate, which is more typical for small pores, or participate in the transport of the adsorbate to the retention site, which is more typical for larger pores. The greatest sorption effect, confirmed experimentally, is achieved by obtaining a sorbent with a pore distribution specified in tables 1, 2. As the feedstock, buckwheat husk is used as a potassium-enriched product. The preferred use of buckwheat husk as a raw material is associated with economic feasibility, which is explained by the formation of a large amount of waste (buckwheat husk) in the production of buckwheat.

These signs of the sorbent are achieved during the process of its production under a certain mode, namely, at a temperature range of 460-700 ° C. Compliance with such a regime ensures the maximum production of deaf pores, namely, pores that do not communicate with the surrounding pores and inter-pore space in the immediate center of the sorbents, which determines their high sorption properties. At temperatures above 700 ° C, as proposed in the prototype method, complete decomposition of the organic matrix and destruction of the organomineral structure occur, which leads to a deterioration of the sorption properties, which in this case only one carbon performs. Lower temperature conditions of heat treatment (below 460 ° C) do not provide a multi-porous structure with a given pore distribution, which negatively affects the efficiency of the sorbent. Examples of the implementation of a new method for producing the sorbent are descriptions of the processes carried out: heat treatment at atmospheric pressure, in a high-frequency plasma at atmospheric pressure, in an arc plasma at atmospheric pressure and in a plasma under reduced pressure (see table 1).

Tests of the sorbent were carried out during the collection of oil products from the surface of the water and during the treatment of industrial wastewater contaminated with oil products. Various oil products were used in the tests: Mordovian-Karmal natural bitumen, Uratminskaya and Privyatskaya oils, Neucen, Rio Negro (Argentina) deposits, mineral and compressor oils produced in Russia and Argentina, oil waste from service stations at facilities in Russia, the Baltic States and Argentina.

Testing the sorbent from the surface of water contaminated with oil

A fixed amount of oil was applied to the surface of the water. Special samplers at three points of the oil slick took samples to determine the concentration of oil in water. Then, the sorbent of the modification of HS was applied to the oil slick and after 15 minutes the sorbent saturated with oil products was collected mechanically. At three points, similar samples were used to sample water after purification. The degree of purification for oil was 98%.

Testing the sorbent in the treatment of industrial wastewater

Water contaminated with oil products was passed through a filter column with a sorbent. The flow rate of the water-oil mixture through the sorbent is 150 ml / min, the water temperature is 12 ° C. Sampling to determine the residual oil content is carried out from the last 100 ml of the mixture that has passed through the sorbent. To determine the degree of purification, 5 ml water samples were extracted with 2 ml of dichloromethane. Concentrated organic extracts were subjected to chromatography - mass spectrometric analysis on a MATN-90 mass spectrometer from Finnigan-MAT. The results of the analysis of water samples obtained after purification of water-oil mixtures showed that the total concentration of oil products even in the sample with maximum saturation does not exceed 0.03 mg / l.

Table 2. The influence of technological conditions on the composition and properties of sorbents GS

table 2
The influence of technological conditions on the composition and properties of sorbents GS Sample No. Options Process temperature ° C 450 460 500 600 700 750 1. Heat treatment The ratio of K: C,% 1: 14.0 1: 16.0 1: 17.5 1: 18.0 1:20 1: 23.7 Pore sizes, (d),% 30-35 microns 0.5 2 5 6 8 nine 20-30 microns 39 35 thirty 29th 26 24 2-20 microns 60 63 65 65 66 67 Sorption capacity (g / g) 1: 3 1: 4.0 1: 4,5 1: 5.5 1: 5.9 1: 3.8 2. Processing in HF plasma atmospheric pressure The ratio of K: C,% 1: 14.0 1: 16.0 1: 17,0 1: 18.0 1: 20.0 1: 23.3 Pore sizes,% 30-35 microns 1 2,5 5 6 8 nine 20-30 microns 39 35 31 29th 26 24 2-20 microns 60 62.5 64 65 66 67 Sorption capacity (g / g) 1: 3 1: 4.0 1: 5.0 1: 5,4 1: 6 1: 3.4 3. Processing in arc plasma The ratio of K: C,% 1: 14.0 1: 16.1 1: 17.4 1: 18.2 1: 19.0 1: 23.0 Pore sizes, (d),% 30-35 microns 1 2,5 4 6 8 nine 20-30 microns 39 35 thirty 29th 26 24 2-20 microns 60 62.5 66 65 66 67 Sorption capacity 1: 3 1: 4.0 1: 4.9 1: 5.5 1: 6 1: 3,5

4. Processing in HF plasma low pressure The ratio of K: C,% 1: 14.0 1: 16.0 1: 17.5 1: 18.6 1: 20.0 1: 23.5 Pore sizes, (d),% 30-35 microns 1 2 6 7 8 nine 20-30 microns 39 35 thirty 29th 26 24 2-20 microns 60 63 64 65 66 67 Sorption capacity 1: 3 1: 4.0 1: 5.5 1: 5.5 1: 6 1: 2,8 ^*) - sorption capacity for oil hydrocarbons.

Figure 2 presents the pore size distribution of the sorbents of the modification of the HS obtained in different ways.

The necessary characteristics of the modification of the HS and technological modes are achieved with the following parameters of the installations:

- With the method of heat treatment in the high-pressure discharge of low pressure: the flow rate of the plasma gas 0.08-0.1 g / s; power in the discharge 1-1.5 kW; pressure in the discharge zone 0.4

- 0.5 atm, process temperature 460-700 ° C. When the method of heat treatment in the HF discharge of atmospheric pressure: the flow rate of the plasma gas 0.1-1.5 g / s; power in the discharge of 40-60 kW; pressure in the discharge zone 1 atm., process temperature 460-700 ° C.

- With the method of heat treatment in an arc discharge: the consumption of plasma-forming gas is 1-2 g / s; power in the discharge of 50-70 kW; pressure in the discharge zone 1 atm., process temperature 460-700 ° C.

- With the method of heat treatment in a drum or shaft furnace: feedstock consumption of 150-450 kg / h; yield of the finished product 50-150 kg / h, process temperature 460-700 ° C.

- With the method of heat treatment in a chamber furnace: loading of raw materials 3-15 kg, yield of the finished product 1-5 kg, process temperature 460-700 ° C. The residence time in the reaction zone is 10-30 minutes.

Claims (5)

1. Sorbent for removing oil and oil products from liquid media, which is a product of processing buckwheat husks, characterized in that it is an organic matrix of a multidimensional porous structure with a pore size of 2-35 μm, with a mineral potassium-containing component distributed in it at a weight ratio of carbon to carbon in a matrix equal to 1: 16-20. 2. The sorbent according to claim 1, characterized in that it has the following pore size distribution: 2-20 μm 63-66%, 20-30 μm 26-37%, 30-35 μm 2-8%. 3. A method of producing a sorbent for removing oil and oil products from liquid media by heat treatment of buckwheat husks, characterized in that the heat treatment process is carried out at a temperature of 460-700 ° C. 4. A method of producing a sorbent according to claim 3, characterized in that the heat treatment process is carried out in a drum, shaft or chamber furnace at atmospheric pressure. 5. A method of producing a sorbent according to claim 3, characterized in that the processing process is carried out in a plasma of a high-frequency discharge of reduced pressure or in a plasma of a high-frequency or arc discharge of atmospheric pressure.

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