JPH1128724A - Recycling system for foamed styrene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate waste foamed styrene into polystyrene and purified air in a short period of time. SOLUTION: The recycling system for foamed styrene is fabricated such that a rotation spindle 2 is disposed vertically in a cylindrical dissolution distillation bath 1, a desired number of steps of cyclone turbine fins 4 having a stirring and separation function and pushing up contents from the center to the outward upside within the dissolution distillation bath 1 are arranged on the rotation spindle 2, an inlet and outlet for cooling water and evaporation are formed on a jacket 7 formed by constructing a desired part of the sleeve of the dissolution distillation bath 1 into a double structure, a supply screw conveyer 14 provided with a foamed styrene input 13 and an discharge screw conveyer 15 for collected polystyrene are connected to the bottom of the dissolution distillation bath 1, an exhaust pipe 16 for discharging air and solvent gas defoamed from foamed styrene is joined to the upper part of the dissolution distillation bath 1, and the other end of the exhaust pipe 16 is connected to a condenser 17, thus returning a liquefied solvent to a service tank 19, and releasing air in the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycling system for separating used polystyrene (expanded polystyrene) into polystyrene and air as raw materials and recovering polystyrene. In addition to the treatment, the solvent is efficiently recovered and used repeatedly.

[0002]

2. Description of the Related Art Styrofoam, which is generally used, is 50 times expanded, and 98% is made of air and 2% is made of a raw material (polystyrene). For this reason, transporting used styrofoam to a processing plant for processing is like transporting air, and is very inefficient.

[0003] Styrofoam is used in large quantities in various containers and cushioning materials, and is widely used in fish markets, fresh markets, wedding ceremonies, food stores in department stores, and the like. I am very struggling with the processing. Also, in general households, styrofoam trays are often used for food purchased at supermarkets, convenience stores, etc., and these are either discarded as garbage or collected and recycled. I have.

[0004] Conventionally, there is a method of treating waste styrofoam by treating (incineration or landfilling) the waste styrofoam at a refuse treatment plant or by recycling it. However, in order to recycle waste styrofoam, it is necessary to transport the styrofoam to a processing plant, and a method for recycling has not yet been established, and the recycling efficiency itself is poor.

The most efficient recycling method of styrene foam, which is currently considered, focuses on the fact that styrene foam is dissolved in methylene chloride. This is to dissolve in methylene and degas the air, and then recover and reuse the polystyrene dissolved in methylene chloride.

[0006]

However, even if the above method is considered as a recovery method, it is technically immature and has not been completed as a recycling system. Therefore, even in the method of recycling styrofoam using the above methylene chloride, each operation, that is, dissolving styrofoam in methylene chloride and collecting polystyrene dissolved in methylene chloride are each performed as separate operations. Further, as for the apparatus used, a dissolving tank or a distiller conventionally used for other purposes is simply diverted as it is, and it is not particularly considered to be suitable for recycling styrene foam.

Further, since such a general-purpose device is used, a method for recovering and reusing methylene chloride used as a solvent, a method for detoxifying degassed air and releasing it to the atmosphere are disclosed. No appropriate measures have been taken for the means, and there is a problem that recycling of styrofoam causes new environmental problems. In addition, since the still is not intended to recover the polystyrene, the quality of the recovered polystyrene is not satisfactory.

[0008]

In order to solve the above-mentioned problems, a styrene foam recycling system according to the present invention (Claim 1) is provided with a vertically dissolvable cylindrical dissolving distillation tank which is installed vertically. A rotating shaft driven by an arbitrary driving source is vertically arranged at the center of the tank, and the outer peripheral portion of the fin formed with the tip upward in the rotating direction is close to or in contact with the inner wall of the dissolution distillation tank on the rotating shaft. A desired number of cyclone turbine fins having a function of stirring the contents and peeling the contents from the inner wall of the dissolving distillation tank and acting to push the contents upward from the center to the outside in the dissolving distillation tank; A desired portion of the cylindrical portion of the dissolution distillation tank is formed as a cooling / heating jacket having a double structure, and the jacket is provided with an inlet and an outlet for cooling water for cooling and steam for heating, and a cold water source and a steam, respectively. Connected to the source, at any point of the dissolution distillation tank, to supply the polystyrene foam into the dissolution distillation tank, connected to a supply screw conveyor provided with a polystyrene foam input port, and at the bottom of the dissolution distillation tank, For discharging the collected polystyrene from the dissolution distillation tank, a discharge screw conveyor is connected, and at the top of the dissolution distillation tank, an exhaust pipe for discharging air and solvent gas defoamed from styrene foam is connected, The other end of the exhaust pipe is connected to a primary condenser, and the solvent liquefied by the primary condenser is returned to the service tank, and air is released to the atmosphere.

[0009] In addition to the above, at the top of the dissolution distillation tank,
Connect the exhaust pipe for discharging air and solvent gas degassed from the styrene foam, connect the other end of the exhaust pipe to the primary condenser, return the solvent liquefied by the primary condenser to the service tank, and completely liquefy by the primary condenser The solvent mixture gas that was not removed is led to the solvent adsorption device and released to the atmosphere as clean air.The gas adsorbed by the adsorbent is desorbed by heated steam, guided to a secondary condenser and liquefied, and the liquid is decanted by a decanter. And separated into water
The solvent is returned to the service tank (Claim 2), and the solvent mixed gas that has not been completely liquefied by the secondary condenser is sent again to the solvent adsorption device (Claim 3).

Alternatively, in addition to the above, the inside of the dissolving distillation tank is
A vacuum generator is connected so that the degree of vacuum is 0 to 720 mmHg (claim 4).

[0011]

A solvent containing methylene chloride as a main component is put in a dissolution distillation tank, and cooling water is circulated through a jacket to cool the dissolution distillation tank so that the methylene chloride is maintained at about 25 ° C. Waste styrofoam is charged from an arbitrary point through a supply screw conveyor onto the upper surface of the dissolving agent in the dissolving and distillation tank. The supplied polystyrene is immediately dissolved and defoamed by the solvent. The defoamed air and the like pass through a primary condenser and the like, the air is released to the atmosphere, and the solvent component is liquefied and recovered.

When the introduction of the styrene foam into the dissolving distillation tank is completed, the flow of cold water through the jacket is stopped, the dissolving distillation tank is heated to about 50 ° C. by passing steam through the jacket, and the cyclone turbine fin is rotated. The solvent in which the polystyrene is dissolved is pushed upward from the center to the outside in the dissolving distillation tank, and the solvent is stirred so as to press the solvent against the inner wall of the dissolving distillation tank.

The solvent heated in contact with the inner wall evaporates and is liquefied through a primary condenser or the like. On the other hand, the polystyrene is peeled off from the inner wall of the dissolving distillation tank by the peeling action of the cyclone turbine fin, and is separated and deposited on the bottom of the dissolving distillation tank. When the recovery of the solvent is completed, the polystyrene deposited on the bottom of the dissolution distillation tank is discharged and recovered by a screw conveyor for discharge. When the degree of vacuum in the dissolution distillation tank is increased, evaporation of the solvent is promoted and drying of the polystyrene is promoted.

Further, in order to minimize the solvent components in the air released to the atmosphere, the solvent mixed gas not liquefied by the primary condenser is guided to a solvent adsorption device, adsorbs the solvent, is released to the atmosphere, and is adsorbed by the adsorbent. After being liquefied in a secondary condenser, it is separated into a solvent and water and collected.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a styrene foam recycling system according to the present invention will be described with reference to the drawings. Reference numeral 1 denotes a vertically disposed cylindrical dissolution distillation tank which can be sealed during operation. Has become. 2 is a dissolution distillation tank 1
, And is driven in the direction of the arrow at 60 to 90 revolutions per minute by the geared motor 3.

The rotating shaft 2 has a desired number of cyclone turbine fins 4 having a disk-shaped central portion in the rotating direction. In the illustrated example, three stages are shown, but this is appropriately selected depending on the size and height of the dissolution distillation tank 1 and the like. On the outer side of the disk portion of the cyclone turbine fin 4, a fin 6 whose tip is upward with respect to the rotation direction of the rotating shaft 2 and whose outer peripheral portion is close to or in contact with the inner wall 5 of the dissolving and distillation tank partially cuts the disk. The desired number is formed by bending. The cyclone turbine fin 4 has a function of stirring the contents and a function of separating the contents from the inner wall 5 of the dissolving and distillation tank, and also acts to push the contents upward from the center to the outside in the dissolving and distillation tank 1. Any shape may be used regardless of the illustrated shape.

The lower two-thirds of the cylindrical portion of the dissolution distillation tank 1 has a cooling / heating jacket 7 formed as a double structure. This jacket 7 has an inlet 8 and an outlet 9 for cold water for cooling.
And an inlet 10 and an outlet 11 for the heating steam. These are connected to a suitable cold water source (for example, a chiller) and a steam source (for example, a boiler) (not shown). The size and location of the jacket 7 can be selected as appropriate, and may be provided at the bottom of the dissolution and distillation tank 1 or the like. However, it is most efficient that the jacket 7 substantially matches a certain range of the cyclone turbine fin 4. It is.

A supply screw conveyor 14 having an inlet 13 for supplying styrofoam into the dissolution and distillation tank 1 is connected to the bottom 12 of the dissolution and distillation tank 1. In the illustrated example, the connection point of the supply screw conveyor 14 is the bottom portion 12. However, the supply screw conveyor 14 can be connected to any position of the dissolution distillation tank 1, and the dissolving agent is contained in the dissolution distillation tank 1. If the styrene foam can be supplied to the upper surface of the dissolving agent when it is contained, it may be anywhere other than the bottom 12 such as the cylindrical portion or the upper portion. Further, a discharge screw conveyor 15 is connected to the bottom 12 of the dissolution distillation tank 1 for discharging the polystyrene recovered in the dissolution distillation tank 1 from the dissolution distillation tank 1.

An exhaust pipe 1 for discharging air and solvent gas defoamed from styrene foam is provided above the dissolution distillation tank 1.
The other end of the exhaust pipe 16 is connected to a primary condenser 17. The solvent liquefied by the primary condenser 17 is returned to the service tank 19 via the solvent primary return pipe 18 and the air is discharged to the atmosphere as it is, or a solvent mixed gas discharge pipe 20 is connected to the solvent adsorption device 21 as described later. Then, it may be released to the atmosphere via this. In addition, a condensate pump may be provided between the primary condenser 17 and the solvent primary return pipe 18.

With the above structure, the basic system of the styrofoam recycling system of the present invention is completed. However, the following equipment is added in order to increase the distillation rate, increase the solvent recovery rate and increase the cleanliness of the air released to the atmosphere. May be.

First, in order to increase the evaporation rate of the solvent and the drying rate of the polystyrene to promote the distillation rate, an appropriate vacuum generator (not shown) such as a vacuum pump or a bleed ejector is used.
May be connected between the dissolution distillation tank 1 and the primary condenser 17 or to the solvent mixed gas discharge pipe 20 of the primary condenser 17. The inside of the dissolution and distillation tank 1 is cooled to 67 by a vacuum generator.
The degree of vacuum is set to be 0 to 720 mmHg.

Next, an apparatus for improving the solvent recovery rate and the cleanliness of air released to the atmosphere will be described. The other end of the solvent mixed gas discharge pipe 20 connected to the primary condenser 17 is connected to an inlet of a solvent adsorption device 21 via an air filter 22 and a blower 23. The solvent adsorption device 21 is provided with two switchable adsorption cans 25 and 26 in which an adsorption filter 24 made of activated carbon fiber is installed.
When suction is performed by one of the suction cans 25 by switching between a suction valve 27 provided at the inlet of the suction can and a discharge valve 28 provided at the outlet thereof, the other suction can 26 is connected to a steam boiler (not shown). It is heated and desorbed by a steam pipe 29 provided.

The gas not adsorbed by the adsorption cans 25 and 26 is discharged to the atmosphere (50 ppm to 100 ppm) as clean air via an air discharge pipe 30. When the solvent adsorbed by the adsorption filter 24 is desorbed, it is led to the secondary condenser 32 via the solvent mixed gas discharge pipe 31. The solvent liquefied by the secondary condenser 32 is separated into a solvent and water by a decanter 33, and the solvent returns to the service tank 19 via a solvent secondary return pipe 34. The solvent mixed gas that has not been liquefied by the secondary condenser 32 is returned immediately before the blower 23 through the recirculation pipe 35.

In the illustrated example, the solvent adsorption device 21 is of the adsorption-can switching type, but other known systems such as a rotary type can be used for the adsorption can. Further, a solvent injection pipe 36 is connected to the service tank 19, and the other end is connected to an appropriate portion of the dissolving distillation tank 1 so that the solvent in the service tank 19 can be injected into the dissolving distillation tank 1.

The recycling of waste styrofoam by the styrofoam recycling system of the present invention is as follows. First, while passing cold water through the jacket 7 and cooling the temperature in the dissolving distillation tank 1 to about 25 ° C., the solvent 10 containing methylene chloride as a main component is introduced into the dissolving distillation tank 1 from the service tank 19 through the solvent injection pipe 36.
Add 0 liter. As the solvent containing methylene chloride as a main component, for example, methylene chloride (trade name, manufactured by Asahi Glass Co., Ltd.) is used. The dissolving and distillation tank 1 is cooled to prevent the methylene chloride from evaporating during the dissolving and defoaming operation since the boiling point of methylene chloride is about 40 ° C.

When a predetermined amount of the solvent is introduced into the dissolving distillation tank 1, the supply screw conveyor 14 is operated, and the waste polystyrene foam is fed into the dissolving distillation tank 1 through the inlet 13. The styrene foam fed into the dissolution distillation tank 1 is instantaneously dissolved and defoamed in the solvent, the polystyrene is dissolved in the solvent, and the air flows into the primary condenser via the exhaust pipe 16. About 25 to 30 kg of styrene foam is dissolved in 100 liters of the solvent, and the styrene foam is fed into the dissolution distillation tank 1 until a predetermined amount of the styrene foam is fed into the dissolution distillation tank 1. It is preferable that the waste foamed polystyrene is washed with water before being charged and pulverized to an appropriate size.

When a predetermined amount of Styrofoam is fed into the dissolving and distillation tank 1 and the dissolving and defoaming operation is completed, the supply of cold water to the jacket 7 is stopped. Heat 5 to 40-60 ° C. Also, the geared motor 3 is driven to rotate the rotating shaft 2.
To rotate the fins 6 of the cyclone turbine fins 4
The solvent is pressed against the inner wall 5 of the dissolving and distillation tank 5 while stirring so that the solvent in which the polystyrene is dissolved is pushed upward from the center to the outer side, that is, toward the inner wall 5 of the dissolving and distillation tank.

The solvent pressed against the inner wall 5 of the dissolving distillation tank in the form of a thin film is heated by the jacket 7 so that the solvent evaporates and the polystyrene sticks to the inner wall 5 and remains. Then, the polystyrene sticking to the inner wall 5 is scraped off from the inner wall 5 by the peeling action of the fin 6 of the cyclone turbine fin 4, and the scraped polystyrene is deposited on the bottom 12 of the dissolution distillation tank. When the distillation operation is continued in this manner, the solvent is completely evaporated, and only the polystyrene in a substantially dry state remains at the bottom 12 of the dissolution distillation tank.

The solvent gas evaporated in the dissolving distillation tank 1 is led to a primary condenser 17 via an exhaust pipe 16. The solvent liquefied by the primary condenser is the solvent primary return pipe 1
After 8, return to the service tank 19. When a vacuum generator is provided, evaporation of the solvent is further promoted and the drying speed of polystyrene is increased. On the other hand, a condensate pump is connected to the primary condenser 17, and the liquefied solvent returns from the condensate pump to the service tank 19 via the solvent primary return pipe 18.

On the other hand, the gas that has not been liquefied is released to the atmosphere as it is when the solvent adsorbing device 21 is not provided. However, when the solvent adsorbing device 21 is provided as shown in this embodiment, an air filter is provided through the solvent mixed gas discharge pipe 20. 22, and is led to a suction valve 27 of the solvent adsorption device 21 through a blower 23.

In the illustrated example, an example in which the adsorption step is performed in the adsorption can 25 and the desorption step is performed in the adsorption can 26 is shown. Therefore, the suction valve 27 to which the other end of the solvent mixed gas discharge pipe 20 is connected is connected to the adsorption vessel 2 in the adsorption step.
Only 5 opens and the solvent mixed gas enters the adsorption can 25. The discharge valve 28 of the suction can 25 is open and the discharge valve 28 of the suction can 26 is closed. The solvent mixture gas entering the adsorption can 25 has the solvent component adsorbed by the adsorption filter 24, and the component not adsorbed by the adsorption filter 24 is released to the atmosphere as clean air via the air discharge pipe 30.

On the other hand, in the adsorption can 26 which is performing the desorption process, the suction valve 27 is open to the solvent mixed gas discharge pipe 31, and the solvent mixed gas adsorbed by the adsorption filter 24 is discharged from the vapor pipe 29. It is desorbed by the heated steam and is led to a secondary condenser 32 through a solvent mixed gas discharge pipe 31 to be liquefied. The liquefied solvent is guided to the decanter 33 and separated into solvent and water, and the solvent returns to the service tank 19 via the solvent secondary return pipe 34.

The solvent mixed gas not liquefied by the secondary condenser 32 is led to the outlet of the air filter 22 through the recirculation pipe 35 and sent to the solvent adsorption device 21 again by the blower 23. Solvent used is almost 100% by primary condenser 17 and secondary condenser 32
It can be recovered, and the recovered solvent can be used repeatedly through the service tank 19.

When the distillation operation is completed, the discharge screw conveyor 15 is operated, and the polystyrene deposited on the bottom 12 of the dissolving distillation tank is discharged from the dissolving distillation tank and collected. Since the recovered polystyrene is not heat-treated, it can be pelletized and reused as a plastic raw material. In the case of the capacity described in the above embodiment, one recycling operation is completed in a total of 30 minutes for each of the dissolution operation and the distillation operation for 15 minutes. In addition, when two dissolution distillation tanks are installed, the distillation operation can be performed while the dissolution operation is being performed on one side, and the recycling operation can be continuously performed.

[0035]

As described above, according to the styrofoam recycling system according to the present invention (claim 1), a cylindrical dissolvable distillation tank that can be sealed is installed vertically, and an optional dissolving distillation tank is provided at the center of the dissolving distillation tank. A rotating shaft driven by a drive source is disposed vertically, and the outer peripheral portion of the fin, whose tip is directed upward with respect to the rotating direction, is close to or in contact with the inner wall of the dissolving distillation tank on the rotating shaft, A desired number of cyclone turbine fins having a function of stirring and peeling the contents from the inner wall of the dissolution distillation tank and acting to push the contents upward from the center to the outside in the dissolution distillation tank are arranged in a desired number, and the cylinder of the dissolution distillation tank A cooling and heating jacket is provided at a desired location in a double structure, and an inlet and an outlet for cooling water for cooling and steam for heating are provided on this jacket, and the jacket is connected to a cold water source and a steam source, respectively. At any point in the tank, a feeding screw conveyor with a styrofoam input port for supplying styrene foam into the dissolving distillation tank is connected.At the bottom of the dissolving distillation tank, the recovered polystyrene is dissolved and distilled. Connect a discharge screw conveyor for discharging from the tank, connect an exhaust pipe for discharging air and solvent gas defoamed from styrene foam to the upper part of the dissolution distillation tank, and connect the other end of the exhaust pipe to the primary Connected to the condenser, the solvent liquefied by the primary condenser is returned to the service tank and the air is released to the atmosphere, so that dissolution and distillation can be performed in one device, and the solvent is cooled during dissolution Stirring during distillation.
The dissolution and distillation are completed in a short time by heating the dissolving distillation tank while performing the stripping action, and the gas components are liquefied and recovered by the condenser, so that the solvent can be used repeatedly without being released to the atmosphere. This has the effect that a large amount of styrofoam can be efficiently recycled in a short time.

According to the styrofoam recycling system of the present invention (claims 2 and 3), in addition to the above, an exhaust pipe for discharging air and solvent gas defoamed from the styrofoam is provided above the dissolution distillation tank. And connect
The other end of the exhaust pipe is connected to the primary condenser, the solvent liquefied in the primary condenser is returned to the service tank,
The solvent mixed gas that was not completely liquefied by the primary condenser is led to the solvent adsorption device, and the gas is released to the atmosphere as clean air.The gas adsorbed by the adsorbent is desorbed by heated steam, and is led to the secondary condenser for liquefaction. Then, this liquid was separated into solvent and water by a decanter, the solvent was returned to the service tank, and the solvent mixed gas that was not completely liquefied by the secondary condenser was sent again to the solvent adsorption device. Can be more reliably liquefied, and the amount of the solvent contained in the clean air released to the atmosphere can be extremely small.

According to the styrofoam recycling system of the present invention (claim 4), in addition to the above, a vacuum generator is connected so that the inside of the dissolving distillation tank has a vacuum of 670 to 720 mmHg. The evaporation of the solvent and the drying of the polystyrene can be promoted without heating to a very high temperature, so that the distillation can be performed in a short time. Can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a styrofoam recycling system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dissolution distillation tank 2 Rotating shaft 3 Geared motor 4 Cyclone turbine fin 5 Dissolution distillation tank inner wall 6 Fin 7 Jacket 8 Cold water inlet 9 Cold water outlet 10 Steam inlet 11 Steam outlet 12 Dissolution distillation tank bottom 13 Input port 14 Supply screw conveyor 15 Screw conveyor for discharge 16 Exhaust pipe 17 Primary condenser 18 Primary solvent return pipe 19 Service tank 20 Solvent mixed gas discharge pipe 21 Solvent adsorption device 22 Air filter 23 Blower 24 Adsorption filter 25 Adsorption can 26 Adsorption can 27 Suction valve 28 Discharge valve 29 Steam Pipe 30 Atmospheric discharge pipe 31 Solvent mixed gas discharge pipe 32 Secondary condenser 33 Decanter 34 Solvent secondary return pipe 35 Recirculation pipe 36 Solvent injection pipe

Claims (4)

[Claims] 1. A cylindrical dissolving and distillation tank capable of being sealed is vertically installed, and a rotating shaft driven by an arbitrary driving source is vertically arranged at the center of the dissolving and distillation tank. The outer peripheral portion of the fin with the tip formed upward in the direction is close to or in contact with the inner wall of the dissolution and distillation tank, and has the function of stirring the contents and peeling off the contents from the inner wall of the dissolution and distillation tank and dissolving the contents in the dissolution and distillation tank A desired number of cyclone turbine fins that act to push up from the center to the outside in the inside are arranged in a desired number, and a desired portion of the cylindrical portion of the dissolution distillation tank is formed as a double structure as a cooling and heating jacket, and this jacket is used for cooling. Provide an inlet and an outlet for cold water and heating steam, connect to the cold water source and steam source, respectively, and at any part of the dissolution distillation tank, supply port of Styrofoam for supplying Styrofoam into the dissolution distillation tank Connect the supply screw conveyor provided, and connect the discharge screw conveyor for discharging the recovered polystyrene from the dissolution distillation tank to the bottom of the dissolution distillation tank, and at the top of the dissolution distillation tank, Connect the exhaust pipe for exhausting air and solvent gas degassed from the styrene foam, connect the other end of the exhaust pipe to the primary condenser, return the solvent liquefied by the primary condenser to the service tank, and release the air to the atmosphere. A styrofoam recycling system characterized by discharging. 2. An exhaust pipe for discharging air and solvent gas defoamed from styrene foam is connected to the upper part of the dissolution distillation tank, and the other end of the exhaust pipe is connected to a primary condenser.
The solvent liquefied by the primary condenser is returned to the service tank, and the solvent mixed gas that is not completely liquefied by the primary condenser is led to the solvent adsorption device and released to the atmosphere as clean air, and the gas adsorbed by the adsorbent is desorbed by heated steam And
2. The styrofoam recycling system according to claim 1, wherein the liquid is introduced into a secondary condenser to be liquefied, and the liquid is separated into a solvent and water by a decanter, and the solvent is returned to a service tank. 3. The styrofoam recycling system according to claim 2, wherein the solvent mixed gas not completely liquefied by the secondary condenser is sent again to the solvent adsorption device. 4. A vacuum generating device is connected so that the inside of the dissolution distillation tank has a degree of vacuum of 670 to 720 mmHg.
The styrofoam recycling system according to claim 2 or 3.