RU2767070C1 - Method of producing polymer-bitumen binder and installation for implementation thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods and devices for producing polymer-bitumen binders PBB used in road construction, as well as in making roofing and waterproofing materials, sealants and mastics. Method includes: loading into a container for liquid components of bitumen and a plasticiser, supplying the obtained mixture using a pump through a flow meter to a mixer, into which a thermoplastic elastomer is added from a dispenser of solid components, obtained mixture of liquid and solid components is fed into a dissolver, and the mixture is fed by a pump through a flow meter into a container for unloading the finished product. Mix of components is additionally mixed by means of mixer installed between dissolver and container for finished products. Apparatus includes: a container for liquid components connected by a pipeline equipped with a pump and a flow meter to a mixer, to which a dispenser of solid components is also connected. Mixer is connected by means of pipeline to dissolver, outlet hole of which is connected to finished product container by means of pipeline equipped with pump and flow meter, wherein mixer is arranged between dissolver and finished product for additional mixing and final homogenisation of produced mix.

EFFECT: higher efficiency and lower costs of obtaining high quality PBB.

2 cl, 2 dwg

Description

The invention relates to methods and devices for producing polymer-bitumen binders (PBB) used in road construction, as well as in the manufacture of roofing and waterproofing materials, sealants, mastics, etc.

In essence, PMBs are thermoplastic elastomers of various types and structures dissolved in bitumen, for example, styrene-butadiene-styrene (SBS) thermoplastic elastomer or divinyl-styrene thermoplastic elastomer (DST). Thermoplastic elastomers have the ability to stretch when hot and become elastic when cold, that is, under normal conditions they behave like vulcanized rubber, and when hot they behave like virgin rubber.

At present, the most effective methods for obtaining PMB are technologies using colloid mills, with the help of which thermoplastic elastomers are crushed and then dissolved in bitumen. When grinding thermoplastic elastomers, the specific contact surface of the mixed components increases, and, accordingly, the processes of swelling and dissolution of thermoplastic elastomers in bitumen are accelerated.

There are two main methods for the production of PMB:

1) According to the first method, all PBB components are mixed in one container. First, bitumen is fed into the container, previously dehydrated and heated to a temperature of 110-120°C. Then the required amount of plasticizer, heated to a temperature of 90-100°C, is supplied there, and the resulting mixture is stirred until homogeneous, after which, during mixing, thermoplastic elastomer is introduced in portions, the mixture is gradually heated to a temperature of 155-160°C and then it is sent into a colloid mill, in which the thermoplastic elastomer is crushed into small particles and mixed into the bitumen. From the mill, the mixture is fed into maturation tanks, where the final swelling of the thermoplastic elastomer takes place within a few hours. After that, the PMB is ready for use.

2) According to the second method, a solution of thermoplastic elastomer is preliminarily prepared in a plasticizer at the concentration that was previously set when selecting the PMB composition, and then the resulting solution is introduced into dehydrated and heated bitumen, after which, at the end of the process, surfactants are introduced into the solution and mix it until smooth. If the viscosity of the thermoplastic elastomer solution is very high, and as a result of which it is difficult to mix it or pump it into consumable containers, then bitumen is added to it in an amount equal to the content of the solution in the container, due to which a bitumen-containing thermoplastic elastomer solution is obtained, which is then injected into the bitumen and mix until smooth.

Surfactants are used to accelerate the process of grinding and swelling of thermoplastic elastomer, to reduce the process temperature and, accordingly, to minimize costs. Due to this, the need for the introduction of plasticizers is reduced or completely eliminated, and the cost of the produced PMB is also reduced.

In practice, the known methods for the production of PBB include the following main operations: a plasticizer and a thermoplastic elastomer are introduced into a container with bitumen, they are mixed and then fed into a colloid mill, and then into an intermediate container, then the intermediate container and the colloid mill are technologically looped into the so-called "passages" and the mixture is pumped 2-3 times, after which it is transferred to a container with finished products, where the process of final “ripening” of PMB takes place. Thus, several "passes" of the mixture of components through the colloid mill are required, since the thermoplastic elastomer, getting into the bitumen, is "encapsulated", i.e. its particles are immediately surrounded by a thin bitumen film, which does not allow it to completely dissolve due to the high thermal conductivity of the bitumen itself.

Also known are methods of obtaining PMB using modifiers (polymeric modifying additives).

For example, a method for producing a bituminous composition is known (patent for the invention of the Russian Federation No. 2119513, IPC C08L 95/00, C08L 53/02, C08L 93/00, publ. bitumen, which initially at a temperature of 25-50°C 2-16 wt. % styrene-butadiene thermoplastic elastomer is mixed with 0.7-7.0 wt. % preheated to a temperature of 40-50°C adhesive additive, which is used as tall oil or the product of the interaction of tall oil and triethanolamine at a mass ratio of tall oil: triethanolamine (66-68): (32-34), stirred for 15 min , then the resulting mixture in the form of a free-flowing powder is fed into a container with 77.0-97.3 wt. % of oil road bitumen, preheated to a temperature of 140-160°C, and stirred for 20 minutes.

The disadvantage of the known method is that to ensure the homogenization of the polymer requires the use of expensive components, which affects the cost of the finished product (PMB).

Also known is a device for the production of a modified bitumen binder (patent for the invention of the Russian Federation No. 2627392, IPC B01F 3/14, C10C 3/00, C08L 95/00, publ. 08/08/2017), used to obtain modified bitumen and PBB. The device for the production of a modified bitumen binder contains a container with oil heating coils, thermal insulation, lining with galvanized metal sheets, a hatch, a supply unit for modifying components and a mixer with an electric drive in the form of a paddle device in a cylindrical outer casing with a mixture of bitumen and a modifier taken from the upper layers and fed into tank bottom, inlet and outlet circulation pipes with ball valves heated by thermal oil, bitumen filter, electric pump with inverter and passive hydrodynamic disperser, as well as the dispersant flushing unit as part of the flushing oil tank and oil pump, connected by pipes to the inlet and outlet of the disperser through three-way valves providing flushing of the dispersant with oil flow in the direction opposite to the direction of flow through the dispersant in the bitumen modification cycle. The technical result consists in the production of modified bitumen, including polymer-modified bitumen, without the use of plasticizers, and energy-efficient obtaining of a uniform distribution of the modifying component and/or an optimal continuous spatial structure of thermoplastic elastomers throughout the entire volume of the modified bitumen.

The disadvantage of the technology implemented using the known device is that in order to ensure the homogenization of thermoplastic elastomer with other components (organic binders and additives, for example, adhesives), the use of a "multi-pass" mixing scheme is required, which leads to high energy consumption, as well as to a decrease in productivity or even to stop production due to the use of a filter (21) in front of the disperser (13), and the use of heaters increases the heating time, while it does not exclude the ingress of a coolant composition (thermal oil) into the working volume of the composition, which also does not ensure the safety of the process.

The technical problem solved by the claimed invention is the high labor intensity and low productivity of obtaining a homogeneous solution of thermoplastic elastomer in bitumen, associated with the need to use a "multi-pass" homogenization scheme using colloidal mills, which generally leads to high energy consumption and destruction of thermoplastic elastomer and, as a result, to an increase in the cost of production (PBV).

The technical result achieved with the claimed invention is to increase productivity and reduce the cost of obtaining high quality PMB.

The specified technical result is achieved through the use of a "single-pass" scheme for the dissolution of thermoplastic elastomer in bitumen, as well as the use of a dissolver as a homogenizing reactor.

The proposed method includes the following steps: bitumen and a plasticizer are loaded into a container for liquid components in the required proportions, then the resulting mixture is fed into the mixer using a pump through a flow meter, into which the required amount of thermoplastic elastomer is added from the solid components dispenser, then the resulting mixture of liquid and solid components is fed into the homogenizer reactor, which is used as a dissolver, in which the thermoplastic elastomer is dissolved and homogenized in bitumen, then the mixture of components is mixed using a mixer installed between the dissolver and the finished product tank, and then the mixture is sent to the tank for unloading using a pump through a flow meter finished products.

Additionally, a mixture of liquid components is heated to a predetermined temperature before it enters the mixer using a heat exchanger.

Additionally, adhesive additives are added to the mixture of components using a dispenser connected to the pipeline between the dissolver and the container for the finished product.

To implement the proposed method, an installation is used, including: a container for liquid components, connected via a pipeline equipped with a pump and a flow meter, to a mixer, to which a solid component dispenser is also attached, while the mixer is connected via a pipeline to a dissolver, which, in its The queue is connected to the container for finished products by means of a pipeline equipped with a pump and a flow meter, while a mixer is installed on the section of the pipeline between the dissolver and the container for finished products, which serves for additional mixing and final homogenization of the resulting mixture.

Additionally, a heat exchanger can be installed on the pipeline section between the tank for liquid components and the mixer, which serves to heat the liquid components.

In addition to the section of the pipeline between the dissolver and the container for the finished product, a dispenser can be attached to add adhesive additives to the mixture.

The design of the proposed installation is illustrated by the diagram shown in Fig. 1, and the dissolver operation diagram is shown in Fig. 2.

The installation for the production of polymer-bitumen binder (Fig. 1) contains: a container for liquid components (1) connected by means of a pipeline equipped with a pump (2) and a flow meter (3) to a mixer (4), to which a solid component dispenser is also attached (5), while the mixer (4) is connected via a pipeline to the dissolver (6), which is connected via a pipeline through a pump (7) and a flow meter (8) to a container for finished products (9), while in the pipeline section between a mixer (12) is installed with a dissolver (6) and a container for finished products (9).

Additionally, a heat exchanger (10) can be installed on the pipeline section between the liquid component tank (1) and the mixer (4).

Additionally, a dispenser for adhesive additives (11) can be attached to the pipeline section between the dissolver (6) and the finished product tank (9).

The unit is equipped with standard shut-off valves, filters, sensors and other ancillary equipment not indicated by item numbers in FIG. one.

The operation of the inventive installation is carried out as follows: from the tank for liquid components (1) with a volume ^of 5-50 m CMH-2000/03, into which thermoplastic elastomer is also fed from the solids dispenser (5). After mixing the liquid and solid components in the mixer (4), the mixture is fed into the dissolver (6), where the thermoplastic elastomer is dissolved and homogenized in bitumen. Then, using a pipeline through a pump (7) and a flow meter (8), the mixture is fed from the dissolver (6) into a container for finished products (9).

The operation of the dissolver (6) is shown separately in Fig. 2: due to the intensive rotation of the cutter of the dissolver (13), the liquid mixture, consisting mainly of bitumen and thermoplastic elastomer and falling on the surface of the cutter (13), is thrown from above to the walls of the dissolver (14), and in the liquid under the cutter (13) are formed continuously rotating flows: from bottom to top from the periphery to the center of the cutter, and then back to the walls and down. During rotation in the dissolver of the mixture of components, the particles of thermoplastic elastomer are maximally stretched in the flows of liquid bitumen, while the area of contact between the thermoplastic elastomer and bitumen increases many times, and this improves mixing and dissolution of the thermoplastic elastomer in bitumen.

Thus, unlike a colloidal mill, which mechanically abrades and crushes thermoplastic elastomer particles, in a dissolver their maximum stratification occurs due to the action of tensile forces and their subsequent uniform distribution over the entire bitumen volume up to the formation of a homogeneous thin-layer finely dispersed colloidal mass, in which thermoplastic elastomer particles can no longer stick together or settle under the action of gravity forces.

The inventive installation can be equipped with additional devices that increase the efficiency of its operation (Fig. 1):

A heat exchanger (10) can be used for the purpose of additional heating of the liquid components in the plant.

If necessary, a dispenser (11) can be attached to the section of the pipeline between the dissolver and the container for the finished product, which serves to add adhesive additives to the mixture.

The application of the proposed method allows to obtain the following advantages:

1) The possibility of implementing a streaming production scheme by eliminating the need for "loopback" of the technical process significantly reduces the cost of obtaining the final product, while the single-pass streaming production scheme allows you to produce up to 120 m ^{3 of} the finished product (PBB) per day or 5 m ³ / hour;

2) Possibility of accurate dosing of the used components with guaranteed production of a product with a given composition allows saving raw materials;

3) The method has versatility and simplicity and can be used for the production of PBB with different component composition, while making changes in the technical process requires a minimum reconfiguration of the equipment;

4) The method allows you to fully automate the process;

5) It is possible to produce a minimum volume of the finished product (up to one ton), which allows minimizing costs if it is necessary to produce small batches of PMB.

Thus, the inventive method for producing a polymer-bitumen binder and the installation for its implementation make it possible to obtain PBB in a continuous flow, while by eliminating the "multi-pass" homogenization scheme using colloid mills, productivity is significantly increased and the cost of obtaining high-quality PMB is reduced.

Claims (2)

1. A method for producing a polymer-bitumen binder, including loading bitumen and a plasticizer into a container for liquid components, feeding the resulting mixture using a pump through a flow meter into a mixer, into which a thermoplastic elastomer is added from a solid component dispenser, feeding the resulting mixture of liquid and solid components into a dissolver, feeding the mixture by means of a pump through a flow meter into a container for unloading the finished product, while the mixture of components is additionally mixed using a mixer installed between the dissolver and the container for the finished product. 2. Installation for the implementation of the method for producing a polymer-bitumen binder according to claim 1, including a container for liquid components connected via a pipeline equipped with a pump and a flow meter to a mixer, to which a solid component dispenser is also attached, while the mixer is connected via a pipeline to dissolver, the outlet of which is connected to the finished product tank by means of a pipeline equipped with a pump and a flow meter, while a mixer is installed between the dissolver and the finished product tank, which serves for additional mixing and final homogenization of the resulting mixture.

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