RU2050342C1 - Apparatus to purify compost - Google Patents

Abstract

FIELD: household wastes purification. SUBSTANCE: apparatus is used to purify compost of solid household wastes from salts of heavy and non-ferrous metals and to provide increased quality of purification. Apparatus has initial compost lixiviater made as a tank with located in its bottom part outlet for purified compost ion-exchanging column to purify during lixiviation produced mixture from dissolved in it salts pipeline to feed the mixture from lixiviater into column and for return of purifying mixture into lixiviater and also mean to form pulp of initial compost with lixiviating liquid. Ion-exchanging column has mean for sorbent continuous feeding and discharging. EFFECT: increased quality of household wastes purification and extraction of heavy metals and non-ferrous metals. 2 dwg

Description

 The invention relates to the production of composted fertilizer, obtained in particular from municipal solid waste, and can be used in devices for cleaning compost of undesirable components, especially from salts of heavy and non-ferrous metals (TCM), as well as from other inorganic inclusions.

 A device for separating composted garbage into compost and components unsuitable for use as fertilizers, containing an inclined flat vibrating screen and means for supplying a stream of air through a sieve from the bottom up (application Germany No. 1592784, class C 05 F 9/00, publ. 1973 d).

 Also known is a plant for processing compost obtained from household waste containing a dividing inclined surface and a fan directing a stream of air to a mixture of compost with non-composted substances on this surface to separate it into fractions by density (French application N 2441597, class C 05 F 9 / 02, publ. 1980).

 In these two known devices, the compost is cleaned by separating the mixture by particle size and density, which does not provide the separation of TCM salts from the compost.

 A device for the separation of heavy metals and salts from household waste and similar waste containing a mixing unit for wet waste with dried mineral substances with high sorption ability and a separator for the subsequent separation of waste and mineral substances (application Germany N 3444227, class B 03 B 9 / 06, publ. 1986 g).

 The process of sorption binding of undesirable substances, carried out in a known device in a humidified granular mixture, will not provide sufficient complete purification of compost from salts of TCM.

Also known installation for removing metal compounds from solid materials such as soil, sludge, etc. containing a leachate and a cleaning unit, consisting of a mixer washed from a leach pulp with ion-exchange material and a separator for subsequent separation of the ion-exchange material from the purified solid material [1]
The design of this installation does not provide for pulp circulation between the leachate and the cleaning unit, which does not allow multiple contacting of the material to be cleaned with ion-exchange material and, as a result, does not provide a sufficiently complete cleaning of the solid material from metal compounds. The implementation in a known installation of the cleaning unit from two separate devices (mixer and separator) leads to a complication of the design of the installation. In addition, the combined transportation of particles of solid and ion-exchange materials in one direction from the mixer to the separator complicates the task of separating these materials from each other, and therefore, complicates the design of the separator.

Closest to the invention is a compost purification apparatus comprising a source product leach made in the form of a container with an outlet for a purified product, a purification unit for the mixture obtained from leaching salts dissolved in it, a pipeline for supplying this mixture from the leachate to the cleaning unit, and a pipeline for returning the cleaned mixture to the leach [2]
In the prototype installation, the purification unit is an anaerobic reactor with a fixed catalyst; in this reactor, heavy metal compounds are isolated by converting their dissolved salts into water-insoluble sulfides, which are removed from the reactor as necessary. In the design of the prototype there is no means for intensively mixing the loaded and leach material with the leach fluid, i.e. for pulping of the material to be purified (only the washing of the TCM salts from the stationary material located in the leachant takes place), therefore there is no possibility of effective interaction of compost particles with the reagent in the reactor, as a result, the efficiency of compost cleaning is reduced. The design of the reactor with a fixed reagent also does not provide a sufficiently complete and efficient cleaning of the compost. In addition, the design of the leach in the known installation does not allow to separate from the mass of compost ballast in the form of heavy inorganic inclusions.

 The proposed invention is aimed at solving the problem of creating as simple as possible and sufficiently productive design of a device for cleaning compost from salts of TTMs and other undesirable inclusions. Obtained during the implementation of the invention, the main technical result is to increase the completeness of purification of compost from salts TCM.

 This is achieved by the fact that the compost purification unit containing the leach of the initial product, made in the form of a container with an outlet for the purified product, a purification unit obtained by leaching the mixture of salts dissolved in it, a pipeline for supplying this mixture from the leachate to the cleaning unit and a pipeline for the return of the mixture to be cleaned into the leach, is additionally equipped with a means for the formation of pulp in the leach from the initial product and leachate, the cleaning unit obtained by leaching the mixture and is made in the form of a sorption ion-exchange apparatus with means for continuous input and output of the sorbent, and the outlet for the purified product is made in the bottom of the leach tank.

 The implementation of the cleaning unit in the form of a sorption ion-exchange apparatus ensures high efficiency of the separation of salts of TCM from compost. Means for continuously introducing and removing an ion-exchange sorbent into the apparatus create mobility of sorbent particles in the apparatus, which increases the efficiency of their interaction with the compost pulp, preventing mechanical filtration of the pulp through the sorbent.

 The presence in the proposed installation of a means for the formation of pulp from the compost and leaching fluid in the leachate (for pulping compost) also improves the completeness and intensity of the interaction of compost components with the sorbent.

 The output for the purified compost in the bottom of the leach tank is structurally related to the presence in the proposed installation of means for pulping compost that occurs along the entire height of the leach tank, which determines the discharge of the compost that has settled after cleaning through the bottom of the tank.

 In addition, the ion-exchange apparatus is made in the form of a dish-shaped column, which ensures uniform distribution of sorbent and pulp particles throughout the apparatus and therefore increases the efficiency of their interaction.

 Providing the ion-exchange apparatus with a device for creating pulsations of the cleaned mixture also increases the efficiency of the process taking place in the apparatus.

 In addition, the pipeline for supplying the mixture from the leachate to the ion exchange apparatus and means for removing the sorbent from the device are connected to its lower part, and the pipeline for returning the mixture to be cleaned into the leach and means for introducing the sorbent to the upper part of the device, which provides countercurrent movement of the pulp and sorbent in the apparatus and, therefore, increases the intensity of the process and facilitates the separation of particles of the sorbent from the pulp returned from the ion exchange apparatus to the leach.

 Pipelines for supplying the mixture from the leachate to the ion exchanger and for returning the mixture to be leached to the leachate are connected respectively to the upper and lower parts of the leachate tank, which ensures pulp circulation in the leachate from bottom to top, improving the mixing of the pulp and preventing its separation.

 For additional purification of compost from inorganic ballast, the lower section of the leach tank is made with a collection of solid inclusions.

 In addition, the proposed installation is equipped with a regeneration unit of the sorbent, which allows to reduce its consumption.

 The regeneration unit contains a column for washing the sorbent from suspensions, a column for regenerating the sorbent, a column for washing the sorbent from the regenerating solution, and a conveyor for the restored sorbent connected to the means for introducing the sorbent into the ion-exchange apparatus, which are installed sequentially during the technological process. Washing the sorbent from suspensions is necessary for the effective implementation of the subsequent process of regeneration of the sorbent with an acid solution.

 At least one of the columns of the regeneration unit is equipped with a device for creating pulsations of liquid flows, which increases the efficiency of interaction of the sorbent particles with the corresponding processing fluids.

 The proposed installation can be equipped with a pipeline for supplying washing liquid from the column for washing the sorbent from the suspensions into the leach, which reduces the consumption of leach fluid.

 In addition, the installation can be equipped with a unit for drying the purified compost for delivery of the latter in the form of a finished product, as well as a unit for the deposition and drying of the components of the regenerate obtained as a result of the regeneration of the sorbent, which makes it possible to obtain TTM concentrate as a semi-finished product for non-ferrous metallurgy.

 In FIG. 1 presents a schematic diagram of the proposed installation; figure 2 leach, ion-exchange column and site regeneration of the sorbent.

 The proposed installation contains a leach 1, made in the form of a container, the lower portion of which is made with a collector 2 for collecting and washing solid inclusions from compost, an ion-exchange apparatus in the form of a disk column 3 for extracting dissolved cations from the leach 1, a sorbent regeneration unit 4, a unit 5 for drying the purified compost and a unit 6 for deposition and drying of the components of the regenerate obtained by regeneration of the sorbent in the unit 4.

 For the loading of dry compost into the leach 1 in the cover of the latter, a hatch 7. For supplying pulp from the upper part of the leach tank 1 to the lower part of the column 3, a pipe 8 is provided, and to return the cleaned compost pulp from the upper part of the column 3 to the lower part of the leach tank, the pipe 9 with the pump 10. The pipelines 8, 9 are connected to each other by means of the circulation pipe 11. The pump 10 is designed to feed the pulp from the leach into the column 3 through the pipe 8, and in addition, in conjunction with the pipe 11 constitutes a means for the formation in the leach pulp of the source compost and leaching fluid.

 The lower end of the collector 2 is directly connected to the pipeline 9, the upper end of the collector is also connected to the pipeline through the pipeline 12. At the bottom of the leach tank, an outlet 13 is made in the form of a hatch for unloading the cleaned compost.

 For continuous input of the sorbent into the upper part of the column 3, a feed separator 14 (Trommel type) is provided.

 The sorbent regeneration unit 4 comprises a column 15 for washing the sorbent from suspensions, a column 16 for regenerating the sorbent, a column 17 for washing the sorbent from the regenerating solution, and a recovered sorbent conveyor made in the form of a pipe 18 connected to a separator 14 for returning the sorbent to the column 3.

 For the continuous withdrawal of the spent sorbent from the lower part of the column 3 to the upper part of the column 15, a pipe 19 is installed, equipped with an airlift 20 (pneumatic lift). The lower entrance of the column 15 is connected to the pipe 21 of the water supply. To supply the washing liquid from the upper part of the column 15 to the leach, a pipe 22 is provided.

 To supply the sorbent washed from the suspension from the bottom of the column 15 to the upper zone of the column 16, a pipe 23 with airlift 24 is provided. At the end of the pipe 23, a separator 25 (Trommel type) is installed above the column 16 to separate the sorbent particles supplied to the column 16 from the water. The pipe 26 is designed to return water from the separator 25 to the column 15 through the pipe 21. The lower inlet of the column 16 is connected to the pipe 27 for supplying a regenerating acid solution. The outlet of the regenerate performed at the upper end of the column 16 is connected via a pipe 28 to the unit 6 for the deposition and drying of the regenerate components.

 For pumping the regenerated sorbent from the bottom of the column 16 to the upper zone of the column 17, a pipe 29 with an airlift 30 is provided. The lower entrance of the column 17 is connected to the water supply pipe 21, and the upper liquid output of the column 17 to the pipeline 27. The restored sorbent 18 pipe is connected to the lower part column 17 and is equipped with airlift 31. The pipeline 32 is designed to supply water, separated in the separator 14 from the particles of the sorbent, to the lower inlet of the column 17.

 Each of the columns 3, 15-17 is equipped with a device for creating pulsations (low-frequency vibrations) of the fluid flow in it. The lower entrance of the corresponding column is in communication with the pulsation chamber 33 of this device, which is connected through a pneumatic line to the pulsator.

 The designs of columns 3, 15-17 do not fundamentally differ from each other, while column 17 is installed slightly higher than other columns to ensure the supply of washing liquid from column 17 to column 16 by gravity.

 To ensure the continuity of the compost cleaning process, the installation can be equipped with a second leach identical to the first one and connected to column 3 in parallel with the first.

 To remove the liquid fraction from the leach 1 after completion of the compost cleaning process, a drain pipe 34 is connected to the pipe 9 after the pump 10.

 The deposition and drying unit 6 of the regenerate components may comprise a settling tank 35 for precipitating calcium salt followed by a vacuum filter 36 and a settling tank 37 for precipitating TTM compounds followed by a vacuum filter 38, as well as a spray dryer 39 installed behind the latter.

 Installation works as follows.

 If there are two leachate in the installation, they operate in a semi-continuous mode (alternately), and the remaining nodes in continuous.

 The required amount of leaching fluid is poured into the leach 1, which is water or the liquid phase obtained after settling of the compost pulp at the end of the cleaning process in the second leach or washing water coming from column 15 containing suspended sludge or a mixture of the listed liquids. Next, a dry compost intended for cleaning is loaded into the leach through a hatch 7, which is then pulped using a pump 10. The mass stirred during pulping moves in a closed path: leach 1 pipe 11 pipe 9 (through pump 10) leach 1. As a result, a homogeneous pulp is formed from compost and leach liquid, which is then sent through the following cycle: leach 1 pipe 8 ion exchange column 3 pipe 9 (through pump 10) leach 1. In the process of this circulation, heavy solid inclusions (glass, stones, metal) that are collected in the compost are washed, which are collected in the collector 2. If the layer of these includes If the solution creates significant hydraulic resistance, then the flow of pulp after passing it through the pump 10 can be directed through the pipe 12.

 In column 3, the pulp moves upward in countercurrent with a sorbent, which is used as particles of strongly acidic cation exchanger. The sorbent is continuously introduced into the column 3 through the separator 14 and is discharged at the bottom of the column 3 by an airlift 20 through the pipeline 19. As a result of the interaction of the sorbent with the pulp, metal cations are removed from it due to ion exchange. At the same time, pulp pulsations transmitted along the volume of the column 3 from the pulsator through the pulsation chamber 33 improve the conditions of phase contact.

 In the process of leaching, the most soluble cations (sodium, calcium, magnesium) pass into the liquid phase of the pulp, which are primarily extracted by ion exchange. In this case, an equivalent replacement of these cations with hydrogen ions occurs, as a result, the pulp is acidified. As light metal cations are extracted from the pulp and its acidification from solid particles is increasingly composted, the TCM cations (copper, nickel, cadmium, iron, zinc, lead, etc.) leach into the liquid phase, which also settle on the sorbent. The ion exchange process is stopped after reaching the equilibrium state in the pulp-sorbent system, when almost all alkali, alkaline earth and heavy metals have been extracted from compost. The pump 10 is turned off and allow the pulp to settle in the leach.

After the sludge has settled, the liquid phase is removed from the leach agent through a conduit 34 and then can be pumped into the second leach agent as a leach liquid by a separate pump (not shown). After draining the liquid phase, the ballast fraction of solid inclusions is discharged through the open hatch 13. Then, the mother liquor from CaC ₂ O ₄ precipitation and Ca (OH) ₂ milk of lime solution are respectively added to the condensed pulp of the purified compost for its calcination and deoxidation. The resulting mass is pulped by the pump 10 and discharged from the leach 1 through the hatch 13. The cleaning cycle of the next batch of compost is carried out similarly when the second leach is connected to the ion exchange column 3.

 The mass of purified compost discharged from the leachate 1 is sent to unit 5, where the mass is first dehydrated in a vacuum filter and then in a drying chamber, from where the finished product is obtained in the form of purified and dried compost.

 The filtrate coming from the vacuum filter and the condensed vapor-gas phase formed in the drying chamber can be used as part of the leaching fluid in the cleaning cycles of subsequent batches of compost.

 The sorbent discharged from the column 3 through the pipeline 19 enters the upper part of the column 15, a certain amount of pulp inevitably moves with the sorbent. In column 15, the sorbent moves from top to bottom in countercurrent flow with water flowing into this column through pipeline 21, interacting with it. As a result, the suspended pulp particles (sludge) are washed out of the sorbent and together with the wash water enter the pipe 22, through which the leach 1 returns through the pipe 9, and a part of the washing liquid with sludge enters the second leach for pulping the next batch of cleaned compost.

 The sorbent washed from the suspensions by airlift 24 is transported through a pipe 23 to a separator 25, in which the sorbent particles are separated from the water supplied with them. The water allocated in the separator 25 by gravity flows through the pipe 26 to the pipe 21. The sorbent separated from the water enters the upper zone of the regeneration column 16.

In column 16, the sorbent is in countercurrent contact with a regenerating solution that flows through line 27 to the lower part of column 16. A solution of oxalic acid H ₂ C ₂ O _{4 is} used as the regenerating solution. The regenerated sorbent by airlift 30 is fed through line 29 to the column 17 for washing the sorbent from the regenerating solution. In the process of interaction of the particles of the sorbent with acid, metal cations pass into the liquid phase and, as a part of the regenerate, are supplied via line 28 to the unit 6 for precipitation and drying of the regenerate components.

 In the column 17, the sorbent is washed from the regenerating solution, for which rinsing water enters the lower zone of the column 17 through pipelines 21 and 32. From the upper part of the column 17, the washing solution containing a certain amount of acid flows by gravity into the pipeline 27, where it is mixed with the newly supplied acid solution and is introduced into the column 16 as part of the regenerating solution.

 The sorbent washed in the column 17 with the restored ion-exchange properties by airlift 31 is returned via line 18 to the column 3 through a separator 14, in which the water transported with it is separated from the sorbent, which then returns by gravity through line 32 to the column 17.

The precipitation of the components of the regenerate in the node 6 is carried out in two stages. At first, the regenerate mainly contains calcium oxalate CaC ₂ O ₄ , since during the cycle of purification of compost from the pulp due to ion exchange, the most soluble cations are primarily extracted. The regenerate is sent to a settling tank 35. After settling and decantation of the mother liquor, the thickened pulp is fed to a vacuum filter 36, from which CaC ₂ O ₄ is obtained in the form of a product and the mother liquor CaC ₂ O ₄ , which is then sent to the leach for calcining the pulp of the purified compost. The resulting oxalate contains TCM no more than the maximum permissible norms.

 The subsequent volume of the regenerate leaving the column 16 during the period of active extraction of the TCM cations from the pulp being cleaned is sent to another sump 37. After settling and decantation of the mother liquor, the thickened pulp is fed to the vacuum filter 38. The TCM sludge obtained in the vacuum filter 38 is sent for drying and granulating into a spray dryer 39, from which the finished product is obtained in the form of a concentrate TCM.

Claims (12)

 1. INSTALLATION FOR CLEANING THE COMPOST, containing the leach of the initial product, made in the form of a container with an outlet for the purified product, a unit for cleaning the mixture obtained from leaching salts dissolved in it, a pipeline for supplying this mixture from the leachate to the cleaning unit and a pipe for returning the mixture to be cleaned in the leach, characterized in that it is equipped with a means for the formation in the leach of pulp from the original product and the leaching fluid, the cleaning unit obtained by leaching the mixture is made in in the form of a sorption ion-exchange apparatus with means for continuous input and output of the sorbent, and the outlet for the purified product is made in the bottom of the leach tank.  2. Installation according to claim 1, characterized in that the sorption ion-exchange apparatus is made in the form of a plate column.  3. Installation according to claim 2, characterized in that the sorption ion-exchange apparatus is equipped with a device for creating pulsations of the mixture to be cleaned.  4. Installation according to paragraphs. 2 and 3, characterized in that the pipeline for supplying the mixture from the leachate to the sorption ion-exchange apparatus and means for removing the sorbent from the apparatus are connected to its lower part, and the pipeline for returning the mixture to be cleaned into the leachate and means for introducing the sorbent to the upper part of the apparatus.  5. Installation according to paragraphs. 1 to 4, characterized in that the pipelines for supplying the mixture from the leach to the ion exchanger and for returning the cleaned mixture to the leach are connected respectively to the upper and lower parts of the leach tank.  6. Installation according to paragraphs. 1 to 5, characterized in that the lower portion of the leach tank is equipped with a collection of solid inclusions.  7. Installation according to paragraphs. 1 6, characterized in that it is equipped with a regeneration unit of the sorbent.  8. The installation according to claim 7, characterized in that the sorbent regeneration unit is made in the form of columns for washing the sorbent from suspensions, columns for regenerating the sorbent, columns for washing the sorbent from the regenerating solution and the recovered sorbent conveyor connected to the input means sequentially during the technological process sorbent in the ion exchange apparatus.  9. Installation according to claim 8, characterized in that at least one of the columns is equipped with a device for creating pulsations of liquid flows.  10. Installation according to paragraphs. 8 and 9, characterized in that it is equipped with a pipeline for supplying washing liquid from the column for washing the sorbent from the suspensions into the leach.  11. Installation according to paragraphs. 1 to 10, characterized in that it is equipped with a unit for drying peeled compost.  12. Installation according to paragraphs. 1 to 11, characterized in that it is equipped with a node for the deposition and drying of the components of the regenerate obtained by regeneration of the sorbent.

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