Diffuser-confuser Design Research Articles

Controlling the Activity of Particles of TiCl4–Al(i-C4H9)3 Catalytic System by Changing Their Dispersion Composition in the Process of Producing Low-Molar-Mass Polybutadiene—a Component of Sticky Glue

The influence of the reaction mixture feed rate in a tubular turbulent apparatus with a diffuser–confuser design and its geometric parameters on the fields of turbulent kinetic energy and its dissipation rate has been shown as a result of the physicochemical fluid dynamics modeling of the reaction mixture flow through an apparatus. The reaction mixture consists of toluene, butadiene and particles of the active sediment of TiCl4–Al(i-C4H9)3 catalytic system. It was shown that an increase in the values of the fields of turbulent kinetic energy and its dissipation rate leads to an increase in the degree of dispersion and specific surface area of the catalytically active sediment particles and to an increase of TiCl4–Al(i-C4H9)3 catalytic system activity in the process of obtaining low-molar-mass polybutadiene—a polymer component of sticky glue.

Control of Molar Mass Characteristics of Polybutadiene—a Component of Sticky Glue—by Physical Modification of the Catalytic System in Turbulent Flows

The computational experiments were carried out on the model of butadiene polymerization (toluene as a solvent) in the presence of TiCl4–Al(i-C4H9)3 catalytic system, physically modified in turbulent flows. It was shown that, the higher is the feed rate of reaction mixture into the tubular turbulent apparatus with diffuser-confuser design, and the larger is the ratio of the diffuser diameter to confuser diameter, and the greater is the diffuser opening angle, the lower are the number-average and mass-average molar masses of polybutadiene. These values of number-average and mass-average molar masses of obtained polybutadiene under upper conditions allows using it as a polymer component of sticky glue.

Effect of Physical Factors during the Preparation of a Reaction Mixture in Turbulent Flows on the Rate of Butadiene Polymerization in the Presence of TiCl4-Al(i-C4H9)3 and Molecular Mass Characteristics of Butadiene Rubber

Butadiene polymerization was used as a model of diene polymerization in the presence of micro-heterogeneous Ziegler-Natta polycentric catalytic systems (TiCl4-Al(i-C4H9)3 catalytic system, toluene solvent, temperature 298 K). It was found that an increase in the rate of feeding of the reaction mixture into a tubular turbulent apparatus of diffuser-confuser design, the ratio of diffuser to confuser diameters, and diffuser opening angle led to a local increase in the kinetic energy and dissipation rate of turbulence; as a consequence, the most probable equivalent radius of the catalyst particles and the average molecular mass of the polymer decreased, while the polymerization rate increased. It was also found that a change in the section length to diffuser diameter ratio when the former or latter was constant and a change in the number of sections of the tubular turbulent apparatus from four to eight did not affect the polymerization rate and the molecular mass characteristics of the polymer.

Industrial Trials of a New-Generation Contactor for the Process of the Sulfuric-Acid Alkylation of Isobutane with Olefins

The process of the sulfuric-acid alkylation of isoparaffins with olefins in a new-generation reaction apparatus, namely, the energy-efficient tubular contactor with diffuser–confuser design, which operates in the mode of jet agitation of raw material flows and a catalyst with the arrangement of internal cooling due to partial evaporation of isobutane, has made it possible to obtain high-octane hydrocarbon fractions with a content of 3-methylpentanes of up to 47 wt % and an octane number of up to 92. Energy efficiency has been achieved by eliminating the external cooling of the reaction mass, mechanical agitation, and additional pump-forced circulation equipment. The results of the industrial trials of the new contactor have been described.

Macrokinetics of Polybutadiene Production on a Titanium Ziegler–Natta Catalyst System Prepared in Turbulent Flows

The research was directed at establishing the dependence of the disperse composition of particles of TiCl4–Al(i-C4H9)3 catalytically active precipitate, and their activity and molecular weight characteristics of polybutadiene formed in their presence on the length of sections and the confuser diameter of the tubular turbulent apparatus of diffuser–confuser design used to prepare a catalytic system in turbulent flows. An approach that combines methods of computational fluid dynamics (ANSYS Workbench 17.1 platform) and formal kinetics, and solves inverse problems of kinetics has been used to solve the stated problem. The following required dependences were established based on numerical experiments on the models developed using this approach: (1) the hydrodynamics of the process of dispersing particles of TiCl4–Al(i-C4H9)3 catalytically active precipitate in a tubular turbulent apparatus with diffuser–confuser design, and (2) macrokinetics of butadiene polymerization on the particles of TiCl4–Al(i-C4H9)3 catalytically active precipitate dispersed in turbulent flows (batch reactor, the solvent was toluene, and the temperature of the process was 25°С).

Relationships between the activities of the growth centers of macromolecules in the TiCl4–Al(i-C4H9)3 catalytic system and the particle size of its catalytically active residue

The theoretical regularities of the physical modification of the TiCl4–Al(i-C4H9)3 catalytic system (dispersion of the particles of its catalytically active residue) in eddy flows created in a tubular eddy apparatus of diffuser confuser design were determined. The change in the particle size of the catalytically active residue of the TiCl4–Al(i-C4H9)3 catalytic system as a result of growth of macromolecules during the ion-coordination polymerization of butadiene (“wedging” effect) was described in terms of the probability theory. The relationships (at 298 K) between the activities of the growth centers of macromolecules in the TiCl4–Al(i-C4H9)3 catalytic system physically modified in eddy flows and not physically modified and the equivalent radius of the particles of its catalytically active residue were represented as functional dependences.

Use of a turbulent prereactor for affecting the site multiplicity of a titanium catalyst for (co)polymerization of butadiene and isoprene

The possibility of using a turbulent prereactor of diffuser-confuser design for directional synthesis of butadiene and isoprene polymers and copolymers on a multisite titanium catalyst was examined. Preliminary forming of the reaction mixture under turbulent conditions decreases the contribution of low- and high-molecularmass modes with smoothing of nonmonotonic dependences of the intermediate-molecular-mass modes on the monomer ratio, which is due to disintegration of catalyst particles.

Synthesizing polyisoprene on titaniumium catalysts modified in turbulent flows

Microheterogeneous titanium catalyst is now widely used in the production of stereoregular polyisoprene, one of the highest-volume products in the current production of synthetic caoutchouc. This work considers the principles of the formation of titanium catalyst at temperatures from −10 to −15°C and isoprene polymerization in a medium of aliphatic solvent (isopentane) under conditions of altered hydrodynamic movement of a catalytically active particle suspension. Agitation is intensified via turbulization of the suspension flow in the external circulation contour during the process of active site formation and their collection for polymerization. A small tube turbulent apparatus of diffuser-confuser design is used at this stage for the first time. Isoprene polymerization proceeds on one type of sites that form polymers with narrow molecular weight distributions (polydispersity coefficient 2.1–2.8). More reactive macromolecule growth sites can be obtained as a result of the hydrodynamic impact on the industrial microheterogenic titanium catalyst during its preliminary formation, due to circulation in the tubular apparatus. This ensures the synthesis of high-molecular polyisoprene that has a more stable Mooney viscosity parameter. Modifying the titanium catalyst through the hydrodynamic impact on a suspension of catalytically active particles during the formation of a catalytic system is an effective method for improving the corresponding stage of the industrial production of polyisoprene.

Reducing consumption of titanium catalyst in stereospecific polymerization of butadiene

The possibility of reducing the consumption of titanium catalyst in butadiene polymerization by using a tubular turbulent prereactor of the diffuser-confuser design in the step of mixing the reaction mixture components was examined.

Synthesis of antiagglomeration agent based on calcium stearate for synthetic rubbers in tubular apparatus

Formation of an antiagglomeration agent for synthetic rubbers, based on an aqueous suspension of calcium stearate, by the reaction a highly concentrated solution of calcium chloride (up to 40 wt %) and a dilute solution of potassium stearate (up to 5 wt %) in a small tubular apparatus of diffuser-confuser design was studied.

Decrease in Content of Insoluble Fraction in cis-1,4-Polyisoprene in Formation of Titanium Catalyst in Turbulent Flow

The effect caused by using a tubular prereactor of the diffuser-confuser design operating in the turbulent flow mode on the content of the insoluble gel fraction in cis-1,4-polyisoprene obtained on a Ti/Al catalyst is studied.

Formation of Reaction Mixture in the Course of Preparation of cis-1,4-Polyisoprene in the Turbulent Mode

The effect of a piperylene modification of Ziegler-Natta catalytic systems was studied by sedimentation analysis in the gravity field. The rate of isoprene polymerization was analyzed as influenced by additional crushing of catalyst particles and formation of uniform reaction mixture in mixing of the initial components in a tubular turbulent prereactor of the diffuser-confuser design.

Preparation of Homogeneous Emulsions in Tubular Turbulent Apparatus of Diffuser-Confuser Design

Changing the design of small-size tubular turbulent apparatus of diffuser-confuser design and the hydrodynamic mode of moving dispersed flows allows effective control over the quality of emulsions obtained from two immiscible fluids.