RU2296709C1 - Plant for production of granulated carbon sorbent - Google Patents

Abstract

FIELD: sorption technology; plants for production of granulated recuperated carbon sorbents.

SUBSTANCE: proposed plant includes unit for preliminary preparation of starting material with metal separator, carbonizer with furnace, water cooler mounted at outlet of carbonizer discharge chamber, raw material grinder and separator, unit for mixing ground raw material with binder, mixture granulation unit, granulated material drying unit connected with carbonizer in form of rotary muffle furnace of double-pipe type and finished product unit. Proposed plant makes it possible to obtain granulated recuperated carbon sorbent at high strength and wide range of use entrapping vapor of solvents at boiling point above 100°C and below 100°C.

EFFECT: enhanced efficiency; reduced heat and power requirements.

1 dwg, 1 ex

Description

The invention relates to the production of granular sorbents from organic waste, in particular to plants for the processing of solid waste utilization of rubber-containing (based on natural, butadiene, styrene, isoprene and other rubbers) and polymeric (such as polyethylene, polystyrene, nylon, nylon, lavsan and t .p.) of waste, and can be used to obtain granular recuperation carbon sorbents designed to trap hydrocarbon vapors, primarily gasoline.

The production of carbon sorbents is of utmost importance for eliminating the effects of man-made and anthropogenic activities. Carbon sorbents are widely used in various fields of the national economy, in particular for the separation of gas mixtures and the recovery of vapors of volatile solvents.

The main traditional raw materials for producing carbon sorbents are natural carbon-containing materials: fossil coals, peat, wood, as well as waste from their processing - lignin, agricultural waste, etc.

The properties of active carbons are directly dependent on the raw material used and develop during its processing into active carbons, the main stages of which are carbonization - thermal degradation of the starting material in order to create the primary porous structure and strength properties of the product, and activation - high-temperature oxidation with a gas-vapor agent (gas-vapor) or physical activation) or treatment with chemical reagents (chemical activation) in order to develop a given pore structure in the entire volume, we activate th particle. Plants that implement methods for producing sorbents by carbonization of raw materials with their subsequent activation require large energy costs.

Currently, the development of a wide range of carbon sorbents produced in plants using modern technologies with low energy consumption, including from new non-traditional types of raw materials, including natural and synthetic carbon-containing materials, is very relevant.

A known installation for the production of granular activated carbon from peat (RF Patent N 2171779, С 01 В 31/08, 2001), including a unit for preparing raw materials for grinding and bringing it to a finely dispersed state, a unit for mixing pre-prepared raw materials with an activator and a binder, mixture granulator, granule dryer, carbonization furnace and steam-gas activator.

The disadvantages of this installation are the presence of energy- and resource-intensive combined-cycle activator, as well as the use of a natural fuel source - peat as a raw material.

A known installation for producing granular coal (RF Patent N 2145938, 01/31/08, 2000), including a unit for preparing the feedstock for grinding it, a unit for mixing it with a binder, a granulator mixture, a carbonization furnace, an activator, a cooling and impregnation unit granules after cooling with a solution of thermosetting synthetic carbon material and a unit for heat treatment of granules in an inert gas atmosphere. The resulting sorbent has a sufficiently high adsorption capacity for vapors of organic substances with a boiling point of 60-100 ° C.

The disadvantages of this installation is the presence of energy and resource-intensive activator and narrow selectivity of the properties of the resulting sorbent.

The closest in technical essence to the proposed one is the installation for the production of granular activated carbon from waste tire recycling (TSS) (RF Patent N 2142357, В 29 В 17/00, 1999), including a raw material preparation unit containing a crusher for grinding raw materials, a metal separator and a separator-sieve, a unit for mixing crushed raw materials with a binder, a drum-granulator mixture, a drum-carbonizer, an activator drum, a drum-refrigerator and connecting pipelines.

The disadvantages of this installation are the presence of energy and resource-intensive activator.

The objective of the proposed technical solution is to obtain an energy-saving, reliable and environmentally friendly installation for processing solid carbon-containing residues of the process for recycling rubber-containing waste (waste tire recycling - TSS) into a granular recovery carbon sorbent.

The technical result from the use of the proposed installation is to obtain granular recuperation carbon sorbents with high strength for trapping solvent vapors with boiling points above 100 ° C and below 60 ° C while reducing energy consumption.

The problem is solved, and the technical result is achieved due to the fact that the installation for the production of granular carbon sorbent from waste tires or a mixture of waste tires with polymer waste, including a unit for the preparation of feedstock containing a raw material grinder, metal separator and separator, a mixing unit for crushed raw materials with a binder, a granulation unit of the mixture, a carbonizer with a furnace and a finished product unit, is equipped with a drying unit for granular raw materials containing a dryer with a heater and a bunker - a drive of dry granules with a lock feeder, a rotary muffle furnace of the “pipe in pipe” type with a loading device and an unloading chamber connected to the dryer calorifier is used as a carbonizer with a furnace, the lock feeder of the dryer storage hopper is connected to the carbonizer loading device, and the preparation unit the feedstock is equipped with a water cooler installed at the outlet of the carbonizer discharge chamber.

A diagram of the proposed installation is shown in the drawing.

The installation comprises a unit for preparing the feedstock, a unit for mixing it with a binder, a unit for granulating the mixture, a unit for drying granular materials, a unit for receiving finished products and connecting pipelines. The feedstock preparation unit contains an accumulating feed hopper 1 with a swinging feeder 2, a metal separator 3, a conveyor belt 4, a storage hopper 5, a lock feeder 6 and a loading device 7 of the carbonizer 8 with a discharge chamber 9 and a furnace 10. The discharge chamber 9 of the carbonizer 8 is connected with a drum water cooler 11 installed at its outlet, a hopper 12 with a feeder 13, a grinder (for example, a vibratory mill) 14 and a separator 15. The mixing unit of the prepared feedstock with a binder contains a twin-shaft brush a mixer 16 and a container with a binder 17. The granulation unit contains an extruder type screw press granulator 19 with a screw feeder 18. The granular raw material drying unit contains a belt dryer 21 with a belt feeder 20 and a heater (not shown in the drawing) connected to the carbonizer 8, and the hopper storage of dry granules 22 with a lock feeder 23 connected to the charging device 7 of the carbonizer 8. The belt dryer 21 is connected to a smoke exhauster 28.

The finished product receiving unit contains a mobile storage hopper of the finished product 24 with a gateway feeder of the finished product 25, a weight batcher 26 and a bag sewing machine 27.

Installation works as follows.

The feedstock from the storage bunker 1 of the raw material storage by the swing feeder 2 is fed to the metal separator 3 and then the belt conveyor 4 is fed to the storage hopper 5, from where the gate feeder 6 is sent to heat treatment in the charging device 7 of the carbonizer 8. As a carbonizer, a rotary muffle furnace of the type " pipe in pipe. " The feedstock after separation of metal inclusions is heat treated in a carbonization furnace 8, while the vapor-gas products from the discharge chamber 9 of the carbonization furnace 8 enter the furnace 10, where they are utilized to produce flue gases. The heat-treated raw materials from the discharge chamber 9 are fed for cooling to a drum water cooler 11 and, after cooling, they are collected in a hopper 12, from where they are sent by a feeder 13 to a grinder 14 (for example, a vibration mill) and to a separator 15. A fraction <0.25 mm is separated on the separator and sent it is fed into a twin-shaft brush mixer 16, and an aqueous solution of lignosulfonate is also supplied from a container with a binder 17. The components are thoroughly mixed with the formation of a homogeneous paste, which is fed by a screw feeder 18 for granulation into the screw press granulator 19 of the extruder type. The obtained granules with a belt feeder 20 are fed for drying to a belt dryer 21, heated by air heated in the heater by flue gases discharged from the carbonizer 8, after drying, the granules are collected in a dry granule storage bin 22 and sent by a lock feeder 23 to the carbonizer loading device 7 and 8 further processed according to the heat treatment scheme of the feedstock. The carbonized granules from the discharge chamber 9 of the carbonizer 8 are fed to a drum water cooler 11 for cooling and, after cooling, are collected in a mobile storage hopper of the finished product 24, which is transferred to the finished product reception department, where the finished product is a granular carbon sorbent through the gateway feeder system of the finished product product 25 and weighing batcher 26 are packed into bags of 15-20 kg, which are sewn up on a bag-sewing machine 27 and sent to the finished goods warehouse.

The fraction of composition> 0.25 mm separated in the separator 15 is returned to the pulverizer 14 for crushing.

The flue gases from the furnace 10 are sent to the annular space of the carbonization furnace 8 and then to the heaters of the belt dryer 21 for heating the air, after which the exhaust fan 28 is emitted through the chimney into the atmosphere.

As the raw material for the production of granular carbon sorbent, use the solid residue of the process for the disposal of rubber waste (used tires and tires) - waste tire recycling (TSS) or a mixture of TSS with polymer waste (polyethylene, polystyrene, nylon, nylon, lavsan, etc. .).

Regarding the sulfur and nitrogen content, the feedstock - OSS - meets the basic requirements for raw materials for the production of sorbents. The bulk density of the OSS (starting material without fractionation) is 0.38 g / cm ³ , the total pore volume is 0.36 cm ³ / g. However, the content of mineral components is higher than normal, which determines the limitation of the field of application of sorbents obtained from the community school.

The feedstock is sorted and, after removal of metal inclusions, is subjected to heat treatment at a rate of temperature rise of ≤10 deg / min to a final temperature of 750-850 ° C.

Heat treatment of raw materials is carried out in a rotary muffle furnace of the "pipe in pipe" type, equipped with a firebox located at the furnace end in close proximity to it. In the process of heat treatment, the feedstock is almost completely “gassed off”. The gas-vapor products released during the heat treatment are sent for combustion to the furnace, where they are disposed of to produce flue gases, which are sent to the annular space of the muffle furnace by countercurrently processed raw materials to heat them, followed by the removal of flue gases to the granule drying stage, after which the cooled flue gases are exhausted through the chimney they are emitted into the atmosphere.

If the heat from the combustion of the gas-vapor products released during the heat treatment is not enough to maintain the heat treatment and drying regime, a certain amount of liquid or gaseous fuel is fed into the combustion chamber, which is also used for the start-up period and putting the furnace into operation.

Heat treatment of raw materials before grinding helps to reduce the hydrophobic properties of the OSS, increases the wettability of the feedstock, which makes it possible to use water-soluble binders of the class of lignosulfonates as a binder before granulation.

The heat-treated raw materials are cooled and crushed, preferably to a fractional composition <0.25 mm, mixed with a binder, which is used as a water-soluble binder of the class of lignosulfonates in an amount of 15-20% by dry weight of the weight of the feed to be mixed with the binder.

Studies have shown that grinding of heat-treated raw materials in a vibratory mill for one minute allows you to get the content of the dust fraction with a degree of grinding <0.25 mm about 68%. This fraction is sent for mixing with a binder, and the remaining fractions are returned to grinding. The increase in grinding time did not increase the dispersion of the resulting dust, while an increase in the content of larger fractions was observed due to the aggregation of over-crushed particles into larger conglomerates.

The obtained granular sorbents are cooled and sent to the consumer.

Example.

Solid carbon-containing waste tire recycling (TSS) with the following characteristics is subjected to processing:

bulk density - ≥40 g / cm ³ ;

mechanical strength - ≤15%;

total porosity - 0.36 cm ³ / g;

ash content - ≤13%;

volatile content - ≤25%;

carbon content - 94 ± 2%;

sulfur content - 2 ± 0.5%;

nitrogen content 0.5 ± 0.3%

The bushes are sorted in order to extract foreign matter, primarily metal, leading to breakage of the grinding equipment. Then, to eliminate the negative role of the hydrophobicity of the processed raw materials, it is subjected to heat treatment in a rotary muffle furnace of the pipe-in-pipe type at a temperature rise rate of 8 deg / min to a final temperature of 800 ° C (processing time about 100 minutes). In this case, the heating of raw materials in a muffle furnace is carried out by burning steam and gas products formed in the process of heat treatment. The calorific value of combined-cycle products fed to the afterburner in the furnace, which is equipped with a muffle furnace, is more than 12800 kcal / kg. The flue gases resulting from the combustion are fed into the annulus of the muffle furnace with a temperature of 900 ° C, and taken out of it into a dryer with a temperature of 500 ° C. As experiments have shown, intense gas formation begins after 500 ° C and proceeds at almost constant speed up to 800 ° C.

The resulting material was cooled to a temperature of 20 ° C, crushed to a fractional composition <0.25 mm and subjected to granulation with a 50% aqueous solution of lignosulfonate at a binder flow rate of 15% dry lignosulfonate per mass of granulated OSS. The obtained granules were dried for 3.5 hours at a temperature of 90 ° C and subjected to carbonization to a final temperature of 700 ° C with a temperature rise rate of 7 deg / min.

The heat balance of the sorbent production process at the proposed installation showed that the heat from the utilization of steam-gas products formed during the process of heat treatment and carbonization of the School of Bushes several times exceeds the heat costs of the process of processing raw materials into granular carbon-containing sorbents.

The characteristics of the obtained granular sorbent are as follows:

- bulk density, g / cm ³ - 0.55;

- strength,% - 80.2;

- total pore volume, cm ³ / g - 0.58;

- the volume of macropores, cm ³ / g - 0.22;

- the maximum volume of sorption space for gasoline vapor, cm ³ / g - 0.36;

- ash content ≤16%;

- volatile content - ≤1%;

- carbon content - ≥95%;

- sulfur content - ≤3%;

- nitrogen content - ≤1%

The obtained sorbents belong to the category of recovery sorbents (activated carbons) and have a rather narrow but relevant field of application - recovery of vapors of organic solvents. The obtained sorbents are closest in terms of quality to industrial recovery active coals of AR (GOST 8703-74), which are obtained from coal dust and tar by steam-gas activation method. Depending on the purpose, ARs are issued in three grades:

AP-A - to capture solvent vapors with a boiling point above 100 ° C (toluene, xylene, amyl acetate, etc.);

AR-B - for trapping solvent vapors with a boiling point of 60-100 ° C (benzene, dichloroethane, gasoline, ethanol, etc.);

AR-B - for trapping solvent vapors with a boiling point below 60 ° C (methanol, methylene chloride, acetone, etc.).

For comparison with the sorbent obtained, the qualitative indicators of its industrial analogue, AR-B recovery coal, are as follows:

- bulk density, g / cm ³ - 0.55;

- strength,% - 65;

- total pore volume, cm ³ / g - 0.52-0.58;

- the volume of macropores, cm ³ / g - 0.24-0.27;

- the maximum volume of sorption space for gasoline vapor, cm ³ / g - 0.28-0.31.

Comparison of the obtained granular sorbents with industrial recovery coals shows that the sorbents obtained on the proposed installation have higher strength and have a wide spectrum of action in capturing solvent vapors with boiling points above 100 ° C and below 60 ° C (tested for methanol, benzene, heptane), and therefore, they can replace all three grades of industrial granular recovery active carbon AR.

The constantly growing amount of waste rubber and polymer products, in particular worn-out tires and tires, creates the problem of their disposal and recycling. The burning or disposal of these wastes requires significant energy costs, leads to environmental pollution, as well as the loss of organic and metallic recyclables. As a result of deep complex processing of these wastes by thermal decomposition, in particular, a solid residue is obtained - a carbon-containing product that can be used as raw material for the production of granular carbon sorbent.

The proposed technical solution allows to obtain a carbon sorbent at low energy consumption.

In addition, the vapor-gas products released during the heat treatment process contain several components, of which only one - carbon dioxide - is non-combustible, the rest - hydrogen and various hydrocarbons are perfectly utilized by burning with the release of a large amount of heat. The calorific value of combined-cycle products is more than 12800 kcal / kg, due to which the processing process, for example, waste heat treatment, can be energetically independent and fully recouped - the heat from the combustion of combined-cycle products formed in a carbonization furnace is sufficient to ensure the heat costs of sorbents.

Thus, due to the afterburning of gas-vapor products formed in the process with the formation of flue gases, which are recycled to the process for heating, the heat and energy consumption of the installation is reduced.

Using the proposed installation allows to obtain carbon sorbents of a new generation with low cost.

Claims (1)

A plant for the production of granular carbon sorbent from tire waste or a mixture of tire waste with polymer waste, including a feedstock preparation unit containing a feed chopper, a metal separator and a separator, a mixture of ground materials with a binder, a mixture granulation unit, a carbonizer with a furnace, and a finished product unit , characterized in that it is equipped with a drying unit for granular raw materials containing a dryer with a heater and a hopper storage of dry granules with a gate feeder, as f of the carbonizer use a rotary muffle furnace of the pipe-in-pipe type with a loading device and an unloading chamber connected to the dryer calorifier, a sluice feeder of the dryer storage hopper is connected to the carbonizing loading device, and the feed preparation unit is equipped with a water cooler installed at the outlet of the unloading chamber carbonizer.