HU184241B - Method and apparatus member for carrying out and intensifying processes of heat and/or material transfer between fluid-fluid, fluid-solid phases - Google Patents

Abstract

A process and equipment to enable the intensive realization of head and/or material transfer processes between liquid-liquid and liquid-solid phases in a vessel with a heat exchange jacket (1) achieves an intensive mutual contact and mixing effect by means of a downwardly widening mixing diffusor (12), through which a liquid phase (B) is circulated from an upper portion to a lower portion of the vessel, while intensive heat transfer may be achieved by an optionally selectable and dimensionable external cooler (7). An air bubble (11) formed in diffusor (12) on start-up ensures supply of recycled liquid as a film on the diffusor inner wall. Specified applications are dissolution, extraction, chemical reaction, crystallisation, precipitation, and preparation of suspensions and emulsions. <IMAGE>

Description

The process and apparatus of the present invention allows for the intensive realization of liquid-liquid, liquid-solid heat and / or material transfer processes using conventional autoclaves as basic equipment. The process provides intense contact and mixing effects through a special effect insert which can be inserted into the autoclave for intense heat transfer with an optional and scalable external cooler. The process has the positive effects of my deposit and the intense heat transfer and / or heat transfer. heat dissipation is achieved by circulating the appropriate portion of the liquid phase at an appropriate rate. Intensification of the mixing is done by using the effect of vortex formation in the outer liquid layer underneath the elastic gas stopper, which is placed in my insert and is balanced with the appropriate fluid circulation. The phenomenon of very good mixing conditions in the boundary layer of a gas bubble component forming a large bubble, an elastic gas plug (slug), and a continuous fluid stream adjacent thereto, and a strong turbulence in the liquid space under the gas plug (see Named references: I. Yabe, D. Kunii: Flow Pattern around a Spherical Cap Gas Bubble ... International Chemical Engineering 20, 2, 1980 pp. 203-210 PH Calderbank et al: Mechanics and mass transfer of single bubbles in Free rise ... Chemical Engineering Science 25, 1970, pp. 235-256 - M. Fillaet et al., Gas Phase Controlled Mass Transfer from a Bubble, Chemical Engineering Science 31, 1976, pp. 359-367.

D. J. Nicklin et al .: Two-phase flow in vertical tubes Trans. Inst. Chemical engrs. 40, 1962, p. 61-68. Operational utilization of the phenomenon, such as dual or The possibility of intensifying heat and / or material transfer processes in three-phase systems is not known in the literature, and no commercially applicable solution is available to date.

Our special geometry insert enables the flexible gas plug to be balanced, the fluid circulation rate to be varied within a wider range, and it also provides the possibility of industrial application and size increase.

The most common liquid-liquid and liquid-solid phase heat and material transfer operations in chemical technologies are as follows:

- dissolution, extraction

- chemical reaction in homogenous or heterogeneous liquid phase,

- Selection of solids from solution (crystallization, precipitation, salting) and addition of suspensions and emulsions.

In current plant practice, with some exceptions, these operations are carried out in mixed tanks, autoclaves with heating / cooling jacket.

Although significant new intensive procedures such as fluidization, rotation film, foam column, geyser processes, their industrial spread can only be considered sporadic. One explanation for this is that chemical and allied producers are unable to bear the significant additional costs that would be required to modernize an existing plant. The modern processes mainly involve continuous operation equipment, which would require costly, investment-intensive modifications of the existing equipment, usually based on batch operation technology2.

Although producers recognize the benefits of modern intensive processes (high specific capacity, consistent product quality, etc.), they do not bear the cost and risk of introducing them while a plant, although theoretically outdated, is economically viable. In particular, they do not do so when the current global energy problems and economic difficulties intensify.

On the other hand, however, improving the productivity and product quality of the chemical industry, especially the pharmaceutical industry, and of certain agricultural products on the world market, which can only be achieved through intensive, well-controllable, well-controlled processes.

In order to meet these opposite considerations, processes and equipment designs are required which, at low investment cost, with only minor modifications to existing plant technologies, can operate efficiently, possibly resulting in energy savings and meeting state-of-the-art quality requirements.

The most common appliances in the chemical and allied industries mentioned above are heat-transfer jacketed tanks, ie autoclaves up to a volume of 0.05 m ^{3 to} 10 m ³ . Their greatest advantage lies in their simple operation and character, that they can be used almost universally for the implementation of a wide range of heat and material transfer and chemical conversion processes. It is this fact that explains their popularity, because of its simplicity and unassuming qualities, which are definitely favorable features today and in the future. However, it is regrettable that, in addition to these advantages, this solution is very uneconomical and incapable of accurate operation. The reason for this is that they have a small heat transfer surface in relation to their volume. While the heat transfer surface of a duplicator with a volume of 0.05 m ^{3 has a specific} heat transfer surface of 0.38 m ² , i.e. 7.6 m ² / m ³ , to a volume of 0.15 m ³ only a heat transfer surface of 0.8 m ² , i.e. 5, It has a specific value of 3 m ² / m ³ . As the volume increases, the specific surface area decreases further. Since these devices are mostly equipped with slow-speed mixers - there are technical obstacles to effective mechanical mixing - the solution movement is not satisfactory and the temperature distribution is not uniform. All this results in poor heat and material transfer processes and, due to the design of the equipment, there is no way to intervene quickly and efficiently on the move. Here are two examples of specific problems:

- In the case of crystallization by cooling, the solution layer near the cooling surface is the coldest, the heat removal is the most intensive here. As a result, crust formation, ie crystalline deposition on the cooling surface, is almost inevitable, which rapidly exacerbates the already poor heat transfer. On the other hand, modern crystallization can only be accomplished by controlling, controlling, intense and controllable contact with kinetic processes. In this case, a product of uniform grain quality and size can be produced. However, this requires a programmed change of solution temperature and concentration at a given rate. It is easy to see that a mixed autoclave is not ideal for this.

184 241 - Homogeneous or heterogeneous chemical reactions are known to occur at a given temperature and speed. Most of the reactions are heat-producing, i.e. exothermic. It is very important to quickly and accurately remove the heat of reaction formed. Otherwise, unwanted or potentially hazardous reactions may occur. It is also natural to avoid local overheating or overheating in the solution. In order to carry out the target reaction as much as possible, it is necessary to ensure intensive contact between the reacting phases and the discharge of the product. However, autoclaves are still being used today as reactors. These difficulties are avoided by designing multiple reactor cascades of small volume units, quite energy intensive.

The use of the process of the present invention enables the retention of commercially available or already operating autoclaves as the most expensive piece of equipment. The process utilizes jacket heating and cooling as a tempering option, and intensifies the actual heat exchange in the circulation circuit outside the tank, eliminating heat inertia. At the same time, a special sized, properly sized insert ensures effective mixing and contact of the phases in the tank.

The principle of the process according to the invention and the operation of my special effect insert is illustrated by the description of an assembly of a general purpose, the layout of which is shown in Figure 1.

The container 2, provided with a tempering jacket 1, is used for receiving, contacting and reacting the liquid, liquid-liquid or liquid-solid phases involved in the operation. Of course, in the case of two separate phases, the higher density phase is located in the "A" space of 2 tanks. The tank 2 is tempered through 3 stubs. At the start of the operation, the pump 6 pushes the liquid drawn through the suction nozzle 10 through the heat exchanger 7, whereby the heat exchange medium entering the nozzle 9 cools or heats it to the temperature required for the operation. The fluid column arriving at the calculated flow rate reaches the cartridge 8, displacing the air in the cartridge 8 only so that an air bubble 11 or a flexible gas plug 11 remains in the cartridge 12 for the entire operation, while the cartridge 8 arrives at 13 boundary layers at altered velocity in the film-like layer on the inner wall of its pericarp. By operating all valves 5, the gas can also be formed from inert gas by external inlet, if necessary. The volume of all gas plugs can also be varied by actuating 5 valves as required. In the boundary layer 13, the direction and intensification of the desired process is made possible by the quasi-constant or variable temperature and concentration ratios of the components entering the layer from top to bottom. Continuous renewal of the boundary layer 13 is provided by the continuous elastic movement of the gas plug 11 and the motion energy of the liquid film arriving on the inner wall 12 of the insert 8. As a result of these, the fluid exiting the all liner creates a strong vortex at the outlet and in the fluid space underneath the gas stopper, delivering impulses to the solid phase particles underneath the liner and moving them. The oscillatory motion due to the dynamic balance of the gas plug is taken over by the solid particles under my insert. In crystallization and dissolution, this provides favorable conditions for the material transfer processes to take place, since the relative velocity difference (slip) between the solid particles that carry the oscillating motion and the fluid layers that are displaced by the circulation and constantly renewed will increase. big role.

The resulting product can be removed from the container 2 at the stub 4. It also ensures efficient contact between phases in heterogeneous chemical reactions or liquid-liquid extractions.

Example of solution:

After adding the liquid and solid phases to the tank 2, the operation is started by starting a pump 6 and forming a gas plug 11. The "A" and the "B" formed by the difference in specific gravity are more or less clearly distinguishable solids of different contents, of which "A" is generally more abundant on solids, soluble crystals. At the suction nozzle 10, the solvent exhaled by the pump 6 from space "B" heats up in the heat exchanger 7 and accelerates to the inner wall of my insert 12 into a solid-rich boundary layer 13 where it is intensively moved by a gas plug. The process takes until the solid phase is completely dissolved.

Example of crystallization:

After feeding the saturated solution to the container 2, starting the pump 6 and forming the gas stopper 11, the liquid stream sucked out from the suction nozzle 10 cools in the heat exchanger 7, depending on the choice of operating parameters and to the boundary layer 13, which is intimately mixed by the energy of motion of the incoming film, where the crystal growth reaches a given value due to the given temperature and concentration conditions. Through the temperature and flow parameters, the size of the crystals formed can be influenced. The crystals formed from the 13 boundary layers, respectively. out of its immediate vicinity, they undergo some separation, such that the denser slurry of the larger particles in space A is the dilute phase in space B, which does not settle the small particles at the flow rate determined by the circulating pump for tank 2 contain. Therefore, by adjusting the level of the 10 suction tubes, the lower limit of the particle size range of the crystal formed can be influenced, since the suctioned fine particles continue to grow in the iterative process.

This is not a time saver either, as here we want to make carefully selected, slow, controlled cooling, but it is possible to compare the quality of a calcium chloride product produced in a conventional duplicator with that of a new process. Duplicator: heterogeneous particle size distribution. The particle size ranges from 0.02 mm to 0.3 mm, with an average size of 0.1 mm. The granules are irregularly developed and have a lamellar structure.

By a new method: according to effective mixing and directed growth, the particles have isometric (cubic) habitus that has developed uniformly in all directions. Szemesemére! It varies between 0.1 and 0.25 mm, with an average size of 0.16 mm. The distribution is thus significantly more homogeneous.

-3184 241

Example of solution:

The process of the present invention is compared to a conventional blender duplicator.

Prepare a saturated potassium chloride solution at 450C by placing 450 g of solid salt in 1 liter of water at 20 [deg.] C. or several times in laboratory apparatus. As the solvent warms up, dissolution occurs continuously, so that at 60 ° C, the total solids are dissolved. Make up to 4 to 4 liters of solution in both devices. The duplicator has a volume of 0.1 m ² (duplicate part) with a volume of 4 lO. The solution vessel according to the invention also has a volume of 4 liters and a corresponding tube heat exchanger located on the outside, having a surface area of 0.05 m ² ,

A saturated solution at 60 ° C can be prepared in a conventional duplicator with vigorous mechanical stirring for 30 minutes. Using the same temperature and quantity of heating medium, this time will be only 20 minutes in the new unit. The reason for this is the good mixing conditions in the apparatus and the more efficient circulation of heat 20 in the circulation, even though we used only half the heat transfer surface compared to the conventional apparatus, but a significantly shorter operating time was sufficient.

Other analogous operations in the homogeneous or heterogeneous liquid phase, such as chemical reaction, extraction, etc., can be carried out using the analogous embodiments of the Examples.

The mixing diffuser of the present invention and the process using it have several advantages:

- intensive and continuous reactions can be achieved in simple and conventional double-wall reactors,

- the scale-up of equipment with so many risks in the chemical industry, "engineering", may be omitted, since the flow contact conditions can be kept constant and can be controlled outside the reactor,

- virtually all maintenance can be done outside the reactor as there is no deposit, clogging etc. in the reactor,

- a sufficient number of parallel heat exchangers can maintain constant operation in a conventional batch reactor.

Claims (2)

A process for the realization and intensification of liquid-liquid, liquid-solid, liquid-gas heat and / or material transfer processes in reactors, tanks and conventional autoclaves, characterized in that the heat transfer (heat extraction / heat transfer) is placed outside the reactor in an external circulation circuit. specific heat transfer surface with variable heat transfer rate controlled heat transfer fluid, fluid-liquid (extraction, homogeneous chemical reaction), liquid-solid (solution crystallization), liquid-gas (heterogeneous chemical reaction) material transfer processes contacting to recycle the circulated liquid phase into the reactor or vessel via a special-shaped insert in which a continuously flowing, circulating fluid forms a liquid film between the gas stopper surface and the inner wall of my insert, thereby creating a fluid swirl in the film, creating a strong swirling motion, agitating agitation and dynamic stirring in the fluid space at the exit of the cartridge and below the gas stopper transferred to solid particles or immiscible liquids, thereby increasing the relative velocity difference between the phases, thereby accelerating and intensifying the material transfer processes at the phase boundary surfaces. 2. Insert in variable depth depth in reactors, tanks, autoclaves, characterized in that a gas stopper (11) of variable internal diameter, downstream fluid flow, having at least one upper inlet (5) and at least one lower outlet, can be connected to the fluid circulation circuit. formed.