RU2352624C2 - Method for recycling of waste liquor from grains - Google Patents

Abstract

FIELD: technological processes; chemistry. ^ SUBSTANCE: method provides for preliminary mixing of initial waste liquor with flush water from the stage of press-filter regeneration, filtrate and sediment from neutralisation stage produced in the previous cycle, and then settling in settling tanks, at that more efficient settling of suspended particles takes place due to specified mixing. Then separation is carried out into condensed phase and mother liquid, filtration of produced condensed phase in belt press filters, drying of produced sediment to prepare animal food. Then filtrate is neutralised by lime to produce sediment and neutralised mother liquid, which is purified from dissolved organic compounds, and water is produced, which is suitable for technical purposes. ^ EFFECT: increased efficiency of belt press filter operation due to the fact that only condensed phase of waste liquor is filtrated, and higher yield of fodder product enriched with calcium. ^ 2 cl, 1 dwg, 1 tbl

Description

The invention relates to the alcohol and feed industry, and in particular to methods of processing waste from alcohol production based on grain raw materials to obtain a feed product, and in particular to methods for recycling alcohol stillage.

A known method of utilization of alcohol stillage obtained in the production of alcohol from grain raw materials, involving the cultivation of yeast in it, separation of biomass from the culture fluid, biological treatment of the culture fluid, mixing the biomass of yeast with bacterial biomass of activated sludge and obtaining a yeast-bacterial product (SU No. 841350, C12F 3 / 10, 1980).

The scheme, organized by this method, is quite complex and expensive.

Known methods for the disposal of alcohol stillage by dehydration and obtaining a protein feed product (RU No. 2197690, F26B 5/06, 2003; RU No. 2128688, C12F 3/10, 1999; RU No. 2281322, C12F 3/10, 2006). The processes are carried out in a vacuum volume, in which the holder of the processed substance, a heater, a condenser, a condensate collector, a heat exchanger are placed.

The proposed technological processes are notable for their considerable complexity, energy consumption and extremely low productivity.

There is a method of processing alcohol distillery vinasse by drying the distillery slurry to a moisture content of 10% according to the method of two-stage dehydration (MT Denshchikov. Waste from the food industry and their use. - M.: Pishchepromizdat, 1963, pp. 200-203, Fig. 50). The initial bard with a concentration of 6-8% is subjected to mechanical separation by filtration into a coarsely dispersed phase (grain pellet, flakes, etc.) and a homogeneous suspension, which goes through the evaporation stage in traditional multi-shell evaporator columns, and then dried to a final moisture content. In this case, the pellet is brought to a dry state either by self-processing in a separate drying apparatus, or in a mixture with one stripped off concentrate.

Using this method to obtain dry vinasse for animal feed requires increased energy consumption. In addition, the considered method is characterized by significant environmentally dirty drains.

The closest in technical essence and the achieved result is a method of processing alcohol stillage from grain raw materials to obtain a feed product, which involves separation of large suspended particles (grains) from the initial stillage by settling and filtering through quick filters, neutralizing the resulting acidic colloidal suspension with subsequent coagulation and flocculation of this suspension with the formation of a precipitate and a clarified aqueous phase, separation of the precipitate, its combination with separated large suspended particles (fractions oh) and drying to obtain a marketable product, the aqueous phase purification from dissolved organics to obtain water suitable for industrial purposes (RU №2259394, C12F 3/10, 2005).

The most promising method for separating large suspended particles from the stillage is its filtration on belt filter presses. This process requires less energy compared to settling centrifuges, is technically simpler than drum vacuum filters and allows for a more concentrated sludge compared to simple settling.

The disadvantages of filtration processes using belt filter presses include the need for their regeneration by washing the filter sheet with water to form a large amount of washing water, as well as the sensitivity of the separation process to the concentration of the suspension, the lower its concentration, the more difficult it is to carry out the separation process. In addition, the process of separating suspended particles of alcohol stillage is highly complicated by the high concentration of colloidal particles, the elevated temperature of the initial stillage that goes to disposal (90-100 ° C), and the instability of the stillage composition. This makes it inefficient to use all of the above methods for separating suspended particles of stillage, including using belt filter presses. Moreover, due to the unstable composition of the obtained filtrate, the task of the following stages is complicated: neutralization, coagulation and flocculation, since the effective use of these processes in clarifying the filtrate requires a certain temperature and pH environment, as well as strict adherence to the ratio between suspended colloidal particles and coagulant flocculant.

The technical result of the proposed technical solution is to increase the technical capabilities of the stillage processing, which contributes to the efficient separation of suspended particles of the stillage and purification of the resulting mother liquor.

The specified technical result is achieved by the fact that the method of recycling alcohol stillage from grain raw materials involves separating the grains and suspended particles by settling to obtain the condensed mass and the mother liquor, filtering the condensed mass on belt filter presses, regenerating them by washing with water and drying the precipitate obtained on filter presses with obtaining animal feed, while the mother liquor is neutralized to obtain a precipitate and neutralized mother liquor, which is purified from dissolved organic substances to obtain water for technical purposes, the initial stillage before settling is mixed with the precipitate obtained after neutralization of the mother liquor, the filtrate from the filtration stage and the wash water from the regeneration stage of the filter presses obtained in the previous cycle. Moreover, the total amount of wash water and filtrate introduced into the stillage is not less than 20% by volume of the amount of the initial stillage.

The proposed method for the disposal of alcohol stillage is carried out as follows: the initial stillage is mixed with the precipitate obtained after neutralization of the mother liquor (lime sediment), the filtrate from the filtration stage and the washings from the regeneration stage of the filter press obtained in the previous cycle, then settled in settlers, divided into the condensed phase and the mother liquor, the condensed phase are filtered on belt filter presses (see drawing).

The precipitate obtained on filter presses is dried to a moisture content of mainly 7-11% to obtain animal feed, and the mother liquor is neutralized with lime and, after settling, it is separated into a lime precipitate and a neutralized mother liquor.

The calcareous precipitate is sent for mixing with the initial bard in the next cycle, and the neutralized mother liquor is purified from dissolved organic substances by known methods — it is treated with a coagulant, flocculant and adsorbents to obtain water suitable for technical purposes.

Filter presses are regenerated by washing the web with water. Wash water and mother liquor formed after settling of the stillage are sent to mix with the original stillage in the next cycle.

Dilution of the alcohol stillage with wash water and filtrate before settling dramatically accelerates the sedimentation process of suspended particles. The efficiency of the belt filter press increases, since only the condensed part of the stillage comes to it, which is 20-30% of the volume of the original stillage. By mixing the original stillage with cold wash water, the temperature of the stillage entering the filtration decreases, which ensures normal operating conditions of the filter press. The introduction of calcareous sediment into the initial bard allows reducing the acidity of colloidal suspension, which contributes to a more efficient separation of dissolved organic substances and allows to obtain an additional technical result, namely to increase the yield of animal feed enriched with calcium.

Table No. 1 presents data on the effect of dilution of the original alcohol stillage (ex. Sp. Distillery stillage) with filtrate (filt.) And wash water (industrial water) on the deposition rate of suspended particles of distillery stillage.

Table number 1 No. p / p Quantity added. (industrial water + filter.) ref. cn bardoux,% vol. Deposition rate particles, mm / h Temperature ° C Ref. cn bards Mixes one 0 60 94 94.0 2 5 one hundred 94 90.2 3 fifteen 180 94 83.6 four twenty 250 94 80.0 5 thirty 450 94 75.7 6 fifty 800 94 67.6 7 60 850 94 64.3 8 70 860 94 61,4

The following are examples of specific performance of the proposed method.

Example 1. For disposal received 10 m ³ stillage obtained in the distillery processing grain, with a temperature of 94 ° C and pH = 4.5.

The composition of the stillage, wt.%: Water 89.6%; dissolved organic matter 2.2%; solids of 8.2%.

The original bard was mixed with water coming from the washing stage of the filter cloth, in an amount of 2 m ³ . After settling the mixture, 3 m ^{3 of} condensed matter containing about 220 kg (7.3%) of dry matter and 9 m ^{3 of} mother liquor containing 1.5% of dry matter were obtained. The thickened mass was filtered on a LFG2-1500 belt filter press at a speed of 2.5 m ³ / h; the precipitate was dried in a PCB 750K dryer to a moisture content of 7%. The yield of dry product - animal feed was 645 kg.

To wash the filter press belt, water was supplied at a speed of 10 m ³ / h.

The filtrate (composition, wt.%: 2.4 - suspended particles (dry matter), 0.2 - dissolved organic substances, the rest is water) was mixed with wash water containing 1.2% dry matter, and the resulting mixture in an amount of 11 m ^{3 was} used for mixing with the original bard in subsequent experiments.

The resulting mother liquor was neutralized with lime to pH = 7.5-8.0, and defended for 20 minutes. Received 500 kg of condensed mass (lime sediment) and a neutralized mother liquor. Lime sediment (composition, wt.%: 80.3 - suspended particles, 0.72 - dissolved organic substances, 3.0 - lime, the rest is water) was used for mixing with the original stillage in the subsequent experiments.

The neutralized mother liquor (composition, wt.%: 1.9 - suspended particles, 1.2 - dissolved organic substances, the rest - water) was treated with coagulants, flocculants and sorbents for purification from organics. The obtained purified water contained dissolved organic substances of not more than 20 mg / l and was used for technical purposes.

Example 2. Recycling received 10 m ³ stillage obtained at the distillery processing grain, the composition of example 1. The original bastard was mixed with lime sediment, filtrate and wash water, which were obtained in example 1. After settling was obtained 4.4 m ³ condensed mass and 12.5 m ^{3 of} mother liquor. The thickened mass was filtered on a LFG2-1500 belt filter press at a speed of 2.5 m ³ / h. The resulting precipitate was dried in a dryer PCB 750K to a moisture content of 7%. The yield of dry product - animal feed was 800 kg.

Further, the process was carried out analogously to example 1.

From the above examples it is seen that the introduction of lime sediment in the original bard allows you to increase the yield of animal feed enriched with calcium.

Claims (2)

1. The method of disposal of alcohol stillage from grain raw materials, characterized in that it involves the separation of grains and suspended particles by sedimentation to obtain a condensed mass and mother liquor, filtering the condensed mass on belt filter presses, their regeneration by washing with water and drying the precipitate obtained on filter presses to obtain animal feed, while the mother liquor is neutralized to obtain a precipitate and neutralized mother liquor, which is purified from dissolved organic substances to obtain water for technical purposes, before settling, a similar stillage is mixed with the precipitate obtained after neutralization of the mother liquor, the filtrate from the filtration stage and the washings from the filter press regeneration stage obtained in the previous cycle, and the total amount of washing water and filtrate introduced into the stillage is not less than 20 vol.% the amount of the original bard. 2. The method according to claim 1, characterized in that the precipitate obtained on filter presses is dried to a moisture content of 7-8%.