CZ123694A3 - Method of stimulating generation of biogass during anaerobic fermentation of organic materials and apparatus for making the same - Google Patents

Abstract

This method of stimulating biogas production and the speed of decomposition of organic materials during anaerobic methane fermentation of sludge, waste water and other organic materials is based on the fact that prior to fermentation and/or during fermentation the organic material is mixed with 0.1 to 20% by weight of lyzate according to the dry matter of the fermented material. The lyzate is prepared from the suspended biomass heated at a pH of 6 to 8 and a temperature of 100 to 200 degrees C at a pressure of 0.1 to 1.5 MPa for 0.2 to 10 minutes and then expanded. The equipment for implementing this fermentation method consists of an anaerobic reactor the input of which is connected to the storage unit of the materials intended for the fermentation of the raw sludge and the output from thermal reactor. The output of the anaerobic reactor is connected to the input of the thermal reactor and to the tank for dewatering the stabilised sludge after fermentation. The anaerobic reactor is equipped with an output for biogas and the thermal reactor is connected to the developer of the heating steam. The thermal reactor consists of a head, a shell and a storage tank for the lyzate which are mutually removable by flange joints, the shell consists of at least one element in which there are 2 to 10 spraying bowls.

Description

The invention relates to increasing and accelerating the production of biogas in anaerobic methane fermentation of sludge, waste water and other organic materials, for example in the anaerobic stabilization of livestock crops and in anaerobic wastewater treatment.

BACKGROUND OF THE INVENTION

Anaerobic decomposition - methane fermentation of organic matter is a process in which a mixed culture of microorganisms under anaerobic conditions gradually decomposes a biodegradable organic matter. The final products of decomposition are methane, carbon dioxide, sulphate, nitrogen, hydrogen, biomass formed and stabilized organic matter (no longer decomposable residue).

Among the most important factors that influence the course of anaerobic decomposition of organic substances are substrate composition (also depends on specific production and composition of biogas), presence of nutrients, pH, buffering capacity and temperature.

The presence of a number of inorganic nutrients is important for good anaerobic degradation. The presence of a number of growth factors and vitamins is also important, some of which are able to synthesize microorganisms, others have to be supplied.

The problem is solved by a method of stimulating biogas formation in anaerobic methane fermentation of sludge, waste water and other organic materials of the invention protected by AO 242979. The principle is that it is added to the material to be fermented or directly to the anaerobic reactor as a stimulant mechanically or physically modified biomass suspension in an amount of 0.1 to 10 wt. preferably 5% by weight, based on the organic dry matter of the material to be treated.

Cell crushing on an industrial scale is both plant-intensive and energy-intensive. The same by freezing or ultrasound. - At lower temperatures of from 100 to 200 ° C, too long an exposure time of this temperature is required, increasing the capacity requirements of the plant, which is again uneconomical in industry.

SUMMARY OF THE INVENTION

The aforementioned disadvantages are overcome by the method of stimulating biogas formation and the rate of degradation of organic materials by anaerobic sweep fermentation of sludge, effluents and other organic materials by adding a physiologically modified biomass suspension stimulating agent according to the invention, comprising: or during the fermentation, the biomass suspension is added in an amount of 0.1 to 20% by weight. preferably 10% by weight, based on the dry matter of the fermented material, treated with brief heating for 0.2 to 10 minutes. at a temperature of 100 to 200 ° C and a pressure of 0.1 to 1.5 MPa.

The apparatus for carrying out this fermentation method consists in that it consists of an anaerobic reactor, the inlet of which is connected to a reservoir of material intended for fermentation-raw sludge and the outlet of the thermal reactor, the outlet of the anaerobic reactor is connected via pump to the inlet of the thermal reactor and stabilized sludge after fermentation, the anaerobic reactor is equipped with an outlet for biogas, the thermal reactor is connected to a heating steam generator.

The thermal reactor consists of a head, shell and lysate storage tank which are removable from each other by means of flange connections, the shell is formed by at least one member, the individual shell members are connected by flange connections, in the shell member there are 2 to 8 spray bowls. fixed in the housing member by the post (8) and the spacers, fastened with bolts with nuts to the beams, the spray pans are removable with the support and spacers, and overlap each other alternately for countercurrent and cross-flow heating steam the lysate is closed by a vaulted bottom of the same or larger diameter as the ^one for the lysate preparation method, the jacket is provided with a lysate withdrawal neck, heating steam supply and connections for regulating the temperature, pressure and amount of lysate in the lysate tank. The inlet of a slurry of organic material to be fermented is introduced and the head of the thermal reactor is provided with a safety and vent line.

The terrarium reactor may be seated on legs or suspended on a support structure.

The spray bowls are preferably straight, reinforced ribs,

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The reactor head is preferably provided with a sprayer of decomposed organic material.

The process of disrupting microorganism cells in a thermal reactor can be used to prepare the lysate as a stimulating agent, but also to pre-treat the material to be fermented.

To prepare the stimulating agent, the cell lysate is typically prepared from anaerobic reactor biomass by subjecting a portion of the anaerobic reactor effluent in an amount of 0.1 to 20% (based on the organic dry matter of the material to be treated) for brief heating in a rapid thermal reactor. up to 10 minutes at a temperature of 100 to 200 ° C and a pressure of 0.1 to 1.3 MPa.

A material composed exclusively or predominantly of microorganism cells, for example excess activated sludge, or residual biomass from fermentation processes such as antibiotics, amino acids and the like can also be used for the preparation. In a rapid thermal reactor, under the above conditions, the cell walls of the microorganism cells disrupt, releasing the cell content into solution, thereby increasing their biological activity in anaerobic fermentation. This results in a significant increase in biogas production and a reduction in the amount of excess sludge, including improved drainage.

Heating steam pressure, low residence time required - in order to meet the notion of thermal shock, the physico-chemical character of sludge with a dry matter content of 3 to 8% by weight, which tends to sinter and last but not least a very high temperature gradient of about 100 to 200 ° C disproportionately demanding. For these reasons, conventional heating methods known in the art, for example injector direct heating, are practically unsatisfactory in this case.

For the above-mentioned specific application of heating, a thermal reactor has been designed which meets these technological conditions. The diameter, height and number of trays are variable, given continuously by the size and quantity in the thermal treatment or the amount of recycled sludge, the temperature gradient being processed and the derived countercurrent flowing and condensing ircok vapors. tor V. in Ctelv ·? rn rt! 7'J Γ comes in thermal medium - heating steam spray on straight

In the apparatus according to the invention, the reactor liquid is in direct contact with the heating liquid in the form of droplets on impact and the spray bowl, and a second time with controlled cross-flow of heating steam through the intermittent liquid curtain. intense heating of the liquid and disruption of the microorganism cells.

The height of the liquid level on the spray trays designed as circular segments is minimal. The heated liquid flows from the spray trays by intermittent strands formed by a split overflow onto the chord circular section of the bowl, thereby avoiding the formation of a continuous liquid orifice that could cause shocks in the utility steam condensation in the orifice enclosure of the thermal reactor. By increasing the number of spray bowls and extending the jacket, a large temperature gradient can be achieved, i.e. the temperature difference to be treated between the liquid inlet and the liquid outlet. This method of direct steam heating can be used for all pure liquids as well as liquids with a higher content of suspended matter, at any temperature and corresponding heating steam pressure.

The process according to the invention is economically more advantageous from an industrial point of view than methods of preparing the lysate mechanically or by ultrasound or heating at lower temperatures.

Another advantage is the possibility of lysing even the organic material to be fermented, containing predominantly waste wet organisms, prior to their anaerobic fermentation in the thermal reactor according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the thermal reactor; FIG. 2 is a detail of the spray bowl in FIG. 3 is a detail of the spray bowl in plan view; FIG. biogas by decomposition of organic material.

The cylindrical thermal reactor consists of three main components - the thermal reactor head 1, the housing 2 and the lysate storage tank 3. Both the head and the tank are removable from the housing to the flange connection for cleaning the interior of the thermal reactor, in particular the spray trays.

In the cylindrical head 1, closed by a vaulted bottom, a recycled sludge manifold 4 is installed above the first spray pan, as well as a vent connection and a safety valve. Spray pans 5 are installed in the jacket 2 of the thermal reactor, the position of which is fixed in the jacket 2 by the support and spacing tubes 6. The number of pans and their mutual distance are also variable according to the technological specification. The jacket 2 of the thermal reactor may be integral or split as shown in the figure so that operating personnel can remove or add another part of the jacket and thereby increase or decrease the number of trays to control the amount of temperature gradient being processed, i.e. the temperature difference between the inlet temperature of the recycled sludge and its outlet temperature, i.e. the temperature of the lysate. The spray bowls 5, together with the support and spacer columns 6, are easily removable from the jacket 2 of the thermal reactor or parts thereof.

Due to the consistency of the medium to be treated - a sewage sludge with a higher dry matter percentage - the trays 5 are designed as sprinkler-shaped, circular segments, supported by spacers 6, fastened with bolts 7 with nuts to the beams 8 of the rubber-sealed casing 2. The recycled sludge is sprayed on the bowl and over the divided overflow 9 it falls onto another lower pan. The bowls are straight, reinforced ribs. They overlap each other so that the heating steam advances against the intermittent orifices from the overflow and cross-flow sludge bowls, as shown in the figure. The lysate storage tank 3 is a cylindrical tank enclosed by a vaulted bottom of the same or larger diameter as the jacket 2 of the thermal reactor and connected to the jacket by a flange. It is equipped with lysate sockets, heating steam inlet and sockets for connection of demand control. It is used to minimize the accumulation of lysate required to produce water lysate.

The thermal reactor may be mounted on rolled legs as shown in the figure, or suspended on any suitable support structure.

The thermal reactor is a pressure vessel within the meaning of ČSN 69 00 10 and must therefore be equipped with a safety fitting, officially accepted and equipped with an inspection book.

Exemplary embodiment

The operation of the biogas plant by the decomposition of organic materials is evident from the diagram in Fig. 5. Part of the effluent from the anaerobic reactor 14 is pressurized by the feed pump 15 into the upper part of the thermal reactor 13 into which steam is injected in the lower third. . The cell disruption of the microorganisms occurs in part directly in the thermal reactor 13 at 200 ° C and 1.5 MPa, and in part after the pressure has been released and the temperature has dropped sharply after leaving the thermal reactor 13. The lysate thus prepared is fed directly to the anaerobic reactor. 14, where it is mixed with raw sludge for anaerobic fermentation. The remainder of the effluent after the anaerobic fermentation is led from the anaerobic reactor 14 through a sludge dewatering device 17. The heat required to generate steam is obtained by burning part of the biogas produced.

The amount of effluent from the anaerobic reactor 14 conducted through the thermal reactor 13 was selected so that the temperature in the anaerobic reactor was maintained at 35 ° C, the only heat source for heating the anaerobic reactor being the lysate from the thermal reactor 13.

100 kg of raw sludge for fermentation is sufficient for recycling 11,62%

4 and 4 kg of steam at 200 ° C, which corresponds to a biogas consumption of 0.65 to 0.7,

In classical anaerobic sludge fermentation without the use of stimulant, the following results were obtained: lnr of raw feed sludge contains 43 kg total dry matter kg organic dry matter

Im stabiliz stabilized sludge after fermentation contains kg total dry matter r r Ή ~ ·

Biogas production was 13 m per 1 εη of raw sludge.

Following application of pacing technology according to the above conditions, the following results can be achieved:

and m of input raw sludge contains ´43 kg total dry matter kg organic dry matter

O m stabilized sludge after fermentation contains

16.7 kg of total dry matter

6.6 kg of organic dry matter and a

Biogas production was 26.4 m per 1 m of raw sludge.

Following the application of stimulation technology, an increase in biogas production of 46% and a reduction in dry matter of stabilized sludge of 30% were achieved.

The energy consumption of a conventional fermentation process - the energy consumption for heating the fermenter content is the same as in the process according to the invention.

Industrial use

The invention can be used for the disposal of waste water containing organic substances, in particular for the disposal of waste in the production of antibiotics.

Claims (7)

A method of stimulating biogas formation and the rate of degradation of organic materials in anaerobic methane fermentation of sludge, effluents and other organic materials by the addition of a stimulating agent consisting of a physically modified biomass suspension _; The composition of claim 1, wherein the biomass suspension is added to the organic material to be fermented and / or during fermentation in an amount of 0.1 to 20% by weight. preferably 10% by weight, based on the dry matter of the fermented material, treated by brief heating for 0.2 to 10 minutes. at a temperature of 100 to 200 ° C and a pressure of 0.1 to 1.5 MPa and subsequent expansion. Device for carrying out the method according to claim 1, characterized in that it consists of an anaerobic reactor (14), at the inlet of which a container of material to be fermented is connected and the outlet of the thermal reactor (13), the outlet of the anaerobic reactor (14) via 15) connected to the inlet of the thermal reactor (13) and to the tank (17) for dewatering of the stabilized sludge after fermentation, the anaerobic reactor (14) is provided with an outlet for biogas, the thermal reactor (13) is connected to the steam generator (16). Device according to claim 2, characterized in that the thermal reactor (13) consists of a head (1), a shell (2) and a lysate storage tank (3) which are removable from each other by flange connections, the shell (2) being formed by at least one member, the individual housing members (2) being connected by flange joints, 2 to 8 spray bowls (5) are installed in the housing member (2), the position of which is fixed in the housing member (2) by a column (8) and spacers (6), fastened with bolts with nuts (7) to the beams (8), the spray pans (5) together with the support and spacers (6) are removable and overlap each other alternately for the passage of heating steam in countercurrent and cross-flow upstream the lysate storage tank (3) is closed by a vaulted bottom of the same or larger diameter as the jacket (2), is provided with a lysate neck (11), heating steam supply and connections In order to control the temperature, pressure and amount of the lysate in the lysate tank (3), a feed (4) of a re-fermented organic material suspension is introduced into the reactor head (1) and is provided with a safety and vent line (10). Device according to claim 3, characterized in that the thermal reactor (13) is seated on the legs (12). Device according to claim 3, characterized in that the thermal reactor (13) is suspended on a supporting structure. Device according to claim 3, characterized in that the spray bowls (5) are straight, reinforced ribs in the form of a circular section, provided with a split overflow (9). Apparatus according to claim 3, characterized in that the reactor head (1) is provided with a sprayer of decomposed organic material to be fermented.