SU1632463A1 - Method of purifying water from petroleum products - Google Patents

Abstract

The invention relates to methods for purifying water from petroleum products and allows improving the quality of purification and process efficiency. The method consists in passing the purified water through a two-layer filter containing layers of sorbent and sand and a single-layer sorption filter. In both filters, fossil coal was used as a sorbent, having a BET surface of 25–150 m / g, and the regeneration of both filters was carried out by alkaline treatment in air bubbling mode. 3 hp ff.

Description

The invention relates to the purification of water from petroleum by filtration through coal and can be used to remove petroleum products from natural and waste waters.

The aim of the invention is to improve the quality of cleaning and process performance.

EXAMPLE 1. Water with an oil content of 7.12-3.4 mg / l is subjected to two-stage filtration at a speed of 6 m / h. In the first stage, a two-layer filter is used, in which the ratio of the height of the upper and lower layers is 1: 1. The top layer with a height of 1 m consists of particles of coal 1-3 mm in size, with coal having a BET surface of 150 m / g, represented by 80-85% pores with a diameter of 3.8-4.2 nm, the ash content of coal is 8-15 % The bottom layer of the filter with a height of 1 m consists of sand with a grain size of 0.5-1 mm. In the second stage, a filter with a load of the same angle of 2.5 m height is used.

Purified water after the first filter contains petroleum products 0.4-0.6 mg / l, after the second - 0.1-0.3 mg / l.

After 10 days of continuous operation, the concentration of oil products in the purified water remains the same, but the pressure losses in the first stage filter increase due to clogging of the filter load with suspended substances.

The filter of the first stage is subjected to a hot air-air flushing according to the technology: blowing air with intensity

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16-18 l / s m for 5-7 min, followed by water supply with a temperature of 65-70 ° C, an intensity of 6-8 l / s m for 10-12 min, after which the filtration continues.

After 3 months of work, an increase in the concentration of oil products at the outlet of the second stage filter to 0.4–0.5 mg / l is observed, and carrying out the hot washing of the filter loading of both stages in the indicated mode does not improve the effect.

The regeneration of the loading of the filters of both stages is carried out with alkali according to the following technology: emptying the filters; filling filters with an alkaline solution (pH 9.5-10.5) with a volume equal to 1.2 times the volume of dry loading of filters of the first and second stages; bubbling with air with intensity of 16–18 l / s m2 for 15–20 min; emptying the filter; flushing the filter loading with cold water with an intensity of 5-6 l / s m for 30-40 min. After regeneration, the oily water is filtered through the filters of both stages and a concentration of petroleum products is obtained after the first stage filters 0.4-0.6, and after the second stage filters 0.1-0.3 mg / l.

Thus, the application of the proposed method provides the concentration of petroleum products in purified water at the exit from the filter of the first stage of 0.4-0.6 mg / l, and the second-0.1-0.3 mg / l, which is significantly less than the concentration provided in the prototype (3-4 mg / l). The use of activated carbon provides cleaning to concentrations of 0.01-0.05 mg / l, but the cost of this cleaning is 30-70% (depending on performance) more expensive than in the proposed method.

The duration of the filters in the proposed method compared with the known, using, for example, mesoporous fossil coal, is increased by 500-1000 times.

Example 2. The process is carried out as in Example 1, but the BET surface of the coal is 200 m / g. At the outlet of the filters of the first and second stages, the concentration of oil products is respectively 0.4-0.5 and 0.1-0.2 mg / l. At the same time, the cost of cleaning is increased by 30% due to the additional activation of fossil coal, therefore, despite an increase in the cleaning depth of 0.1 mg / l, the process parameters presented in Example 1 are optimal.

Example 3. The process is carried out similarly to that shown in Example 1, but the BET surface of the coal is 15 m / g at the outlet of the filters of the first and second stages,

the concentration of oil products is respectively 0.9-1.2 and 0.6-0.8 mg / l.

Reducing the surface of coal to 15 m2 / g leads to an increase in the concentration of petroleum products in purified water by a factor of 2-3.

Example 4. The process is carried out as in Example 1, but the ratio of the height of the layers in the filter of the first stage is 4: 1, i.e. the height of the coal in the first stage filter is 2 m, and the sand layer is 0.5 m. In this case, in the second stage filter, the coal layer is 1.5 m high. The concentration of oil products after the first stage filters is 0.2-0, 3 mg / l, and after the filters of the second stage - 0.1-0.2 mg / l.

Example 5. The process is carried out as in Example 1, but the ratio of the height of the layers in the filter of the first stage is 5: 1, i.e. The height of the coal layer in this filter is 5 m, and that of sand is 1 m. The height of the coal layer in the second stage filter is 1.5 m. The concentration of oil products after the first stage filters is 0.2-0.3 mg / l, and after second stage filters -0,1-0,2 mg / l. Periodically, in the process of washing the loading of the filters of the first stage, sand is washed out from the lower layer to the upper layer and then removed from the filter. As a result, there is a periodic leakage of petroleum products with suspended solids up to 1-1.2 mg / l. In this case, it is necessary to overload the filters of the first stage, which increases the cost of water purification by 20-25%.

The proposed method provides a reduction in the concentration of oil products to 0.1-0.5 mg / l when water enters filters with a content of impurities up to 10 mg / l. Such indicators correspond to the operation of activated carbon filters. The method is most appropriate to use after the sump, flotation cell or filter with non-angular loading.

Claims (2)

1. A method of purifying water from petroleum products, including sequential passing of water through a two-layer filter containing an upper layer of granular sorbent, and the lower one from a sandy filter charge, and subsequent regeneration, characterized in that, in order to improve the quality of purification and productivity, water is passed through a single-layer sorption filter and as a sorbent in both filters use fossil coal having a BET surface of 25-150 m2 / g, and regeneration is carried out by washing 5 16324636 hot water and alkaline sand processing load with a particle size of 0.5 solution in bubbling mode. 1 mm when the ratio of the height of the layer of sand to 2. Method pop. 1, characterized by a sorbent layer of 1: 1-4. the fact that fossil coal has pore structure, 80-85% presented time-5 4. The method according to paragraphs. 1-3, differing in diameter of 3.8-4.2 nm, ash content of 8-15%, because before washing the filters are sized for 1-3 mm of particles, then filled with an alkaline solution. The method according to claim 1, о tons of l and h y and with the coarse pH 9.5-10.5, volume 1-1.4 volume by the fact that in a two-layer filter is used-dry loading when airborne airborne.