RU2333049C1 - Method of recycling agro-industrial waste - Google Patents

Abstract

FIELD: agriculture, technological processes.

SUBSTANCE: in the method of initial agro-industrial waste before their loading in the drying chamber are preliminary regulated in water and/or reusable solutions. Through the formed suspension is bubbled compressed air, saline waste material of magnesium and/or potassium production, surface-active substances - water-repelling additives. The clarified liquid phase merges from the lower zone of storage capacity in the holding tank, and the partially-dehydrated agro-industrial waste are unloaded from storage tank in the preliminarily dispersed ejector state, and then it is loaded into the drying chamber. A gas heat-carrier is submitted into the drying chamber, thermal treatment and drying of waste with the subsequent unloading. As salt waste are used the waste products of the dehydration of carnallite, the slimes of carnallite chlorinators, used electrolyte of the process of electrolysis of magnesium from carnallite raw material and sub-standard dust fraction of the process of crushing and/or granulation of potassium chloride.

EFFECT: increase in the efficiency of processing of agro-industrial waste and increase in the productivity of the process.

5 cl, 1 ex

Description

The present invention relates to the field of agriculture, in particular to methods for processing, neutralizing and subsequent disposal of various agricultural wastes generated, for example, at various livestock farms, poultry farms, etc. The present invention can be specifically used in poultry farms for the disposal of highly toxic waste - bird droppings: for its special processing and subsequent disposal in the form of commercial products - environmentally friendly organic and / or complex organo-mineral fertilizers.

There are known (S.P. Botanin, V.A. Chislov. Inventions in industrial poultry farming. Reference. - M.: Rosselkhozizdat. 1987. - 256 p.) Various methods of biochemical and thermal processing of agro-industrial waste - bird droppings. Their disadvantage is the unsatisfactory performance of the process and high energy consumption.

Known (A.A. Kiva, Yu.N. Sukhanov, V.M. Lukyanov. Machines and equipment for poultry farming. Reference book. - M.: Agropromizdat. 1987. - 240 p .; See: p. 173-185: Machines and equipment for transportation and processing of litter) a method of processing agricultural waste - poultry manure to produce a marketable product - organic fertilizers.

This known method is as follows. The initial, raw - wet manure (humidity is usually 75-85%) is initially sent to a vibrating screen to remove foreign objects, after which it is fed with a screw batcher into a metering mixer to mix the raw manure with part of the dried manure. Then the resulting mixture is conveyed by a screw conveyor into a direct-flow drying drum.

Drying (dehydration) is carried out at a temperature in the drying unit: at the beginning of 900 ... 1000 ° C, at the end of 120 ... 160 ° C. From the drying drum, the litter through the unloading device enters the crusher to grind large lumps of dried litter and then to the cooling column for cooling the finished product. Thus obtained product has a moisture content of 12-14% and is a lumpy crumb with a granule size of 1 to 10 mm. From the cooling column, the dried manure is sent by a conveyor to the accumulator, from which the finished product is packaged and / or shipped to consumers.

The disadvantages of this known method is the following:

- sticking of raw manure to the walls of the drum and, in this connection, burning of manure, reduction in the quality and consumer properties of the finished product: reduction in the content of nutrients, useful components;

- the need for special grinding of the finished product;

heterogeneity (from 1 to 10 mm) of the dried and crushed product;

- the need to return the dried product to the "head" of the process to reduce the moisture content of the original product entering the drum for drying. This in turn leads to a decrease in the productivity of the method as a whole;

- large energy costs for dehydration of the initial wet (75-85%) agro-industrial waste - bird droppings (Other known methods have the same drawback: Patents of the Russian Federation No. 209540; 22019909 and others).

Of the known analogues, the closest in technical essence and the achieved result to the proposed invention is a known method of processing and disposal of agro-industrial waste - poultry manure - poultry waste (RF Patent No. 2045497 by application No. 93017460 with prior. Dated 06.04.1993; Zareg. And publ. 10.10.1995; Bull. No. 28; IPC ⁶ A23K 1/00) - "Method of processing poultry waste" - adopted as a PROTOTYPE.

The prototype method includes the following basic operations:

- auger transportation of the initial wet bird droppings from the storage tank to the dispenser;

- introducing litter into the drying chamber in a preliminary dispersed form (in the form of a gas suspension, aerosols) with an initial speed of 25-100 m / s;

- the implementation of the process (drying, neutralization, heat treatment) with the ratio of the rate of introduction of the litter into the working volume of the drying chamber (V _p ) and the feed rate of the gas-coolant (V _gt ) equal to V _p : V _gt = (2-5): 1;

- unloading of the finished product and its packaging.

The method according to the prototype provides, in comparison with other previously known methods, a reduction in the loss of commercial products by preventing the sticking of wet manure on the walls of the drying unit, improving the quality of the resulting product (fertilizers) and increasing the productivity of the process.

The disadvantage of the prototype method is the significant energy consumption for drying and heat treatment, which is associated with high humidity of the initial agro-industrial waste - bird droppings loaded from the storage hopper into the drying chamber. The results of a continuous study over two years of the poultry waste generation system showed that the humidity of poultry manure collected in the house in a storage tank is usually 75-85%, i.e. 3.0-5.5 kg of water per 1 kg of dry solid phase.

The objective of the proposed technical solution is to increase the efficiency of processing of agricultural waste.

The technical result that can be achieved by implementing the present invention is to reduce the specific energy consumption for dehydration and heat treatment of agricultural waste - bird droppings and increase the productivity of the process both in terms of the amount of waste processed and the production of commercial products.

The problem is solved with the achievement of the above technical result by the proposed "Method of processing and disposal of agricultural waste - bird droppings", including loading the waste into the drying chamber in a pre-dispersed state in the ejector, feeding the heat carrier gas into the drying chamber, heat treating and drying the waste, followed by unloading and packing a marketable product.

New in the claimed invention is that the initial agro-industrial waste before being loaded into the drying chamber is pre-repulped in water and / or circulating solutions, air is bubbled through the resulting suspension, salt waste from magnesium and / or potassium production, surfactants are introduced - water-repellent additives, the suspension is kept, the clarified liquid phase is poured from the lower zone of the storage tank into the collection tank, and partially dehydrated agro-industrial waste is discharged from the storage tank second capacity, such as a screw feeder and fed through an eductor into the drying chamber.

A feature of the proposed technical solution is also that salt waste introduced into the slurry after repulping agro-industrial waste uses carnallite dehydration process waste and / or carnallite chlorine sludge, and / or spent electrolyte of magnesium electrolysis from carnallite raw materials, and / or substandard dust fine fraction of the processes of crushing and / or granulation of potassium chloride.

The selection of the above conditions for the implementation of the process according to the proposed method was carried out on the basis of the results of industrial experiments on existing technological equipment for the processing and disposal of agricultural waste, in particular chicken manure. As a result of the analysis of the obtained experimental data, it was found that the above sequence of actions and operations: repulping agro-industrial waste, introducing into the suspension and dissolving salt waste, introducing surfactants - water repellents, sparging compressed air, holding the suspension by settling, separation of liquid and solid phases, liquid discharge water, unloading of the solid (humidity 40-60%) phase, its transportation to the drying chamber, dispersion of partially dehydrated (with the initial humidity of 75-85% to 40-60%) agricultural of waste - chicken manure in the ejector, supply of heat carrier gas to the drying chamber, heat treatment and drying (up to 10-15%) of waste - chicken manure, unloading of the product from cyclones and the expansion chamber together with the mandatory observance of the above process conditions the solution of the problem with the achievement of the technical result, which consists in reducing the specific energy consumption for dehydration and heat treatment and increasing the productivity of the process.

It should be noted at the same time that the technical result of the proposed method is achieved only with simultaneous execution of all the above operations, their specific sequence and compliance with all conditions of the process.

An analysis of the totality of the features of the claimed invention and the technical result achieved in this case shows that there is a well-defined causal relationship between them, expressed as follows.

It was experimentally established that the implementation of the process of processing agro-industrial waste previously repulped in water and / or working solutions, sparging (for example, through a dispersant) of compressed air, sequentially introducing into the suspension and dissolving salt salts of magnesium and / or potassium production first, then high molecular weight surfactants - hydrophobizing additives, aging and sedimentation of the suspension lead to the separation of solid (the actual production waste with low humidity) and liquid water-salt phase and provide, other things being equal (with the prototype) conditions, a significant (2-6 times) reduction in specific energy costs for waste processing in general.

The analysis of the prior art in relation to the totality of all the essential features of the claimed technical solution shows that the proposed method meets the criterion of "novelty."

Verification of compliance of the claimed invention with the requirement of "inventive step" in relation to the totality of essential features indicates that the proposed method does not follow for experts explicitly from the prior art.

In particular, the well-known sources of information (book, magazine and patent literature) do not imply and do not follow the fact that to reduce the initial moisture content (up to 40-60%) of agro-industrial wastes before they are submitted for dispersion (in an ejector), drying and heat treatment in the drying chamber and dryer pipe, it is necessary to increase the humidity of the waste (from 75-85% to 95-98%) by preliminary repulping it in water and / or working solutions.

Such a seemingly illogical technique has not been previously described and has not been used before. Meanwhile, it is this technique, in conjunction with other operations of the proposed method, that ultimately leads to the separation of the solid and liquid phases, the floating (removal to the surface of the aqueous phase) of the solid phase and its partial dehydration: from the initial water content. from (80 ± 5%) to (50 ± 10%). Due to this, the specific energy consumption for dehydration, drying and heat treatment of waste is sharply reduced.

Information confirming the possibility of carrying out the invention is shown in the example.

EXAMPLE

The processing and disposal of agro-industrial waste was carried out on the existing industrial technological equipment of the factory for the processing and disposal of waste from the poultry farm - chicken manure to produce marketable products - environmentally friendly (heat-treated and disinfected) complex fertilizers.

Industrial experiments were conducted according to the prototype method and in accordance with the invention. In all experiments, chicken droppings taken from one collection tank, one house with an initial humidity of 80 ± 2% were used.

According to the known prototype method, the original raw - wet chicken manure (ow. 80 ± 2%) was unloaded from the storage tank (storage hopper) and loaded into an ejector device to disperse the original chicken manure in the volume of the drying chamber, while gas was supplied from the furnace to the drying chamber -heater with an initial temperature of 1200-1600 ° C. The litter was dried at a feed rate into the drying chamber (U _c ) of 50 m / s, and a feed rate of the heat carrier gas (C _g-t ) was 25 m / s. The ratio of the feed rates into the drying chamber of the litter and the heat carrier gas is 2: 1. At the outlet of the dryer pipe, through the discharge devices, an expansion chamber and a cyclone, the finished product (humidity 10 ± 2%) was unloaded and packaged in plastic bags and sent to consumers.

Under these conditions, the specific heat consumption was ≈ 9900 kJ / kg of dry (ow. 0%) chicken droppings.

According to the proposed method, the initial chicken manure (ow. 80 ± 2 ° C), taken from the prefabricated poultry house, was transported by carts to the poultry farm and loaded into the receiving storage hopper, where 3 m ³ per 1 m ^{3 of the} original chicken manure was poured, then through a dispersant placed in the lower zone of the storage hopper, compressed air was bubbled through the suspension, then, with continuous stirring of the suspension, salt waste was loaded into the storage hopper, which were used in various experiments:

- dusty waste from the process of dehydration of carnallite (KCl + MgCl ₂ · 6H ₂ O);

- sludge from carnallite chlorinators (KCl + MgCl ₂ + MgO and small amounts of NaCl, etc.)

- spent electrolyte of magnesium electrolyzers working on carnallite raw materials (~ 75% KCl + 25% Σ MgO, MgCl ₂ , NaCl, etc.)

- dust fraction of potash fertilizers obtained as a result of crushing - granulation of KCl and subsequent classification (more than 95% KCl).

The amount of salt waste introduced is 350 ± 50 kg / m ^{3 of} suspension.

Under these conditions, the density of the aqueous phase after clarification of the solution (and surfacing of the solid phase) was 1.18 ± 0.02 g / cm ³ .

After dissolving the saline waste, a small amount of high molecular weight surfactants (surfactants), water-repellent additives (up to 0.5-2%), was introduced into the pulp. Air sparging through the suspension was carried out for 2 hours. Then, the compressed air supply was stopped, the suspension was kept in the hopper without stirring, while the liquid (water-salt) and solid (actually chicken droppings, partially dehydrated) phases were stratified and the “floating” was the accumulation of the solid phase on the surface of the water-salt solution. The liquid phase - clarified water-salt solution was poured through a siphon pipe into a collection tank. The moisture content of chicken droppings on the surface decreased: from the original - 80 ± 2% to 50 ± 2% (on the surface), which corresponds to a decrease in moisture content from 4 kg of N ₂ O / 1 kg of dry (ow. 0.0%) litter up to ≈ 1 kg H ₂ O / 1 kg of dry (0% water.) litter (0,0 kg H ₂ O / 1 kg of dry solid phase). The specific energy consumption for dehydration of waste by the proposed method decreased by ≈4 times (per unit of dry chicken manure: from 9900 kJ / kg to 2500 kJ / kg or 5 times per unit of manufactured products (dried and heat-treated chicken manure + KCl, MgCl ₂ , MgO) - complex organic and mineral fertilizers, respectively, the productivity of the whole process has increased both in the processed agricultural agro-industrial waste and in commercial products.

Claims (5)

1. A method of utilizing agro-industrial waste, including loading the waste into the drying chamber in a pre-dispersed state in the ejector, supplying heat carrier gas to the drying chamber, heat treating and drying the waste, followed by unloading, characterized in that the initial agro-industrial waste is pre-loaded into the drying chamber they are repulped in water and / or working solutions, compressed air is bubbled through the resulting suspension, salt wastes of magnesium and / or potassium production are introduced, surface o-active substances - water-repellent additives and clarified liquid phase are discharged from the lower zone of the storage tank to the collection tank, and partially dehydrated agricultural waste is discharged from the storage tank and loaded through the ejector into the drying chamber. 2. The method according to claim 1, characterized in that the salt waste introduced into the slurry after repulping agro-industrial waste uses carnallite dehydration process waste. 3. The method according to claim 1 or 2, characterized in that the saline wastes use sludge from carnallite chlorinators. 4. The method according to claim 1, characterized in that the waste electrolyte of the process of magnesium electrolysis from carnallite raw materials is used as salt waste. 5. The method according to claim 1, characterized in that the salt dust is used substandard dust fraction of the process of crushing and / or granulation of potassium chloride.