RU2021347C1 - Apparatus for gas saturation and mixing liquid in reservoir - Google Patents

Abstract

FIELD: chemical engineering, particularly, microbiological industry. SUBSTANCE: apparatus incorporates vertical straight-flow mixing chamber having perforated wall enclosed in additional chamber shaped as box to which is connected gas feed pipe. Box wall also has perforations whose dimensions diminish throughout length of chambers in direction of upflow. Box may have gas discharge openings in its upper portion. In its lower portion, box has liquid drain openings. EFFECT: more effective admixing of gases and liquids. 4 cl, 13 dwg

Description

 The invention relates to a device for saturation of gas and mixing liquids in containers and can be used in apparatus for the cultivation of microorganisms, for example in the production of yeast, in particular bakery, as well as for the homogenization of suspensions, for example in molasses.

 A device [1] for gas saturation and fluid mixing in containers is known, comprising conical plates with annular nozzles at the vertices for liquid intake, installed with the formation of an annular nozzle between them for the exit of a fan stream, a gas turbine of two mounted on a rotating shaft with a gap between them truncated cones and an annular disk with blades.

 A device [2] is also known, consisting of a centrifugal impeller mounted on a shaft rotating with an electric motor with a coaxially located nozzle for fluid inlet in the form of a Venturi nozzle, a chamber with tubes for supplying gas to the fluid, and a gas supply pipe.

The disadvantages of both devices are: complexity, the complexity of manufacturing, high cost and increased energy intensity, which is associated with the presence of a turbine, centrifugal wheel, a rotating shaft, bearings, an electric motor; the ineffectiveness of multiphase fluids (suspensions) associated with separation of particles, such as seed and culture environment (for microorganism cultivation apparatus) or molasses (in melassohranilischah) when rotating mixture flow at ⁹⁰ at the entrance of the impeller (the pre the liquid mixed with gas is separated, as a result of which, for example, in a yeast-growing apparatus, there will be no increase in the saturation of the medium with atmospheric oxygen; the organization of the flow of gas and liquid does not allow vertical downward It makes it possible to use the "free" lifting force of gas bubbles; the possibility of infection of a new portion of biomass when using the device in a cyclically working container, for example in an apparatus for cultivating microorganisms, due to the difficulty of high-quality washing and sterilization of the device after the previous cycle; inefficiency in large containers due to the difficulty of installing multiple devices at the same time.

 Closest to the technical nature of the claimed device is a device [3] for aeration and mixing of liquids to apparatus for growing microorganisms, containing a vertical gas supply pipe with perforation for air supply and a cylinder-conical pipe mounted coaxially to the pipe. In fact, this device is a direct-flow mixing chamber of an annular shape with one of the walls (in this case, the inner one), perforated with gas (air) inlets, and with the direction of gas-liquid flow in the chamber from the bottom up, connected to the gas supply pipe. In this case, the latter is used to form the inner (perforated for gas input) wall of the annular chamber.

 The disadvantages of this device are: unstable operation, which is associated with the implementation of the annular mixing chamber; the formation of large conglomerates of bubbles at the free boundary flowing from the jet mixing chamber; structural complexity due to the need to install pylons for mounting the annular chamber, which, in addition, causes asymmetric flow and also contributes to unstable operation. All this leads to the ineffectiveness of using such a device both in apparatus for cultivating microorganisms (due to insufficient uniform distribution of seed over the volume, air saturation and mixing of the culture medium), and for mixing multiphase liquids in containers (due to the impossibility of achieving a high level homogenization). In addition, the central air supply to the mixing chamber limits the ability to supply large volumes of gas, and also narrows the range of design options for the device.

 The problem to which the claimed invention is directed, was to create a simple compact device that implements effective saturation with gas (for example, air) and (in relation to apparatus for the cultivation of microorganisms) / or (in relation to the homogenization of multiphase liquids) mixing the liquid in the tank.

 The problem is solved by the fact that the above-described device, containing a mixing chamber and a gas supply pipe flowing in the direction of the upper hemisphere of the space, is equipped with a gas supply chamber made in the form of a closed box attached externally to the perforated wall of the mixing chamber and communicating with the gas supply pipe, moreover, the outer side wall of the box is made of perforated openings for gas outlet.

 In special cases, for example, with a relatively large length of the mixing chamber or with relatively small gas flow rates, when the outflow from the openings of the gas supply chamber can be affected by the hydrostatic pressure gradient along the height of the tank, the size of the perforation holes can be made to decrease along the length of the walls in the direction of flow. In addition, the upper end wall of the box can be perforated with openings for gas outlet, and the bottom with drainage holes for draining the liquid, for example, when washing and / or disinfecting the device.

 The implementation of the described combination of essential features of the claimed invention leads to the implementation of a central (in contrast to the annular in the prototype) mixing chamber, which allows to increase the intensity and improve the quality of mixing gas with liquid. Physically, this is explained not only by the advantage of such a camera in terms of process stability, but also to a large extent by the following. Experiments have shown that a secondary swirling flow can be realized in the mixing chamber; therefore, in the annular chamber this effect leads to liquid separation at the outer impermeable wall, and in the central chamber, on the contrary: the liquid ejected into the near-axis region is transferred by centrifugal forces to the perforated chamber wall towards the trickles of injected gas . In addition, an upward flow of gas bubbles formed at the simultaneous outflow of gas through the outer wall of the duct near this wall promotes, as shown by experiments, dispersions of the gas-liquid jet flowing from the mixing chamber, preventing the formation of large conglomerates of gas bubbles at the free boundary of the jet.

 Thus, the technical result achieved by the implementation of the invention is the increase in the degree of saturation with gas and mixing of the liquid in the tank resulting from the foregoing.

 In the case of using the device, for example, in a yeast-growing apparatus, not only does the culture medium intensively saturate with atmospheric oxygen (in the mixing chamber of the device and in the zones above and around it) and it is effectively mixed in the recirculation zone around the device, but another result is achieved, consisting in uniform distribution of seed in the apparatus. In special cases (see above), the implementation of perforation holes decreasing along the length of the device in the direction of flow allows you to level the negative effect of the pressure gradient along the height of the tank on the efficiency of the device (as shown by experiments, such a distribution of holes along the length allows you to redistribute the hydraulic resistance so as to ensure , simultaneous operation of all openings in a wide range of gas flow rates). In addition, the implementation of the upper wall of the duct perforated with openings for gas outlet allows, if necessary, to increase the gas transmission and aeration ability of the device at the same flow rates from the openings and / or to enhance the effect created (see above) by the flow of bubbles from the openings of the outer wall of the duct, and its bottom wall drained simplifies the cleaning and disinfection process after completion of the working cycle of the device.

 The use of a device for mixing multiphase liquids (suspensions) in a container allows to increase the degree of their homogenization before use, which, for example, increases the specific productivity of the yeast-growing apparatus when molasses is used as raw material. In addition, it becomes possible to pre-saturate the initial yeast production with atmospheric oxygen, which also positively affects the performance of the apparatus.

 In FIG. 1 schematically shows the inventive device in section, placed in a liquid (arrows indicate the direction of movement of gas and liquid); in FIG. 2 ... 6 are variants of a device with a mixing chamber, respectively, with a cylindrical (Fig. 2), diffuser (Fig. 3) impermeable and diffuser permeable outlet sections (Fig. 4), in an arrangement with a circulation cup (Fig. 5), with rectangular cross-sectional shape (Fig. 6); in FIG. 7 ... 13 - possible options for placing the device in containers (for example, apparatus for cultivating microorganisms or storage tanks for suspensions): with gas supply through the side wall of the container (Fig. 7) or from above (Fig. 8), with a single-tier placement of several devices with a cylindrical (Fig. 9) or rectangular (Fig. 10) mixing chambers; with multi-tier placement of several devices (Fig. 11); in a layout with an aeration device of another type - tubular (Fig. 12); in layout with panel-type heat exchangers (FIG. 13).

 A device for gas saturation and fluid mixing in containers includes a direct-flow mixing chamber 1 (Fig. 1 ... 13) with a wall 2 (Fig. 1) perforated with openings 3 (Fig. 1) for introducing gas into the chamber in the direction of the upper hemisphere of space mixing 1, a gas supply pipe 4 (Fig. 1... 13) and a chamber 5 (Fig. 1 ... 13) for supplying gas, made in the form of a box attached externally to the wall 2 of the mixing chamber 1 and in communication with the gas supply pipe 4 The outer side wall 6 (Fig. 1) of the box is made of perforated holes 7 (Fig. 1) for the exit of gas.

 The upper end wall 8 (Fig. 1) of the box can be perforated with holes 9 (Fig. 1). Holes 3 and 7 can be made decreasing along the length of the walls 2 and 6 in the direction of flow in the mixing chamber 1. In addition, if necessary, drainage holes 10 can be made in the duct (Fig. 1) for draining the liquid or disinfectant in the duct a sink.

 The size and speed of the gas-liquid jet leaving the device, for example, for different levels of filling the containers with liquid, can be controlled by performing the output section of the mixing chamber 1 impermeable cylindrical (pos. 11 in Fig. 2) and diffuser (pos. 12 in Fig. 3) or permeable diffuser (pos. 13 in Fig. 4). In this case, the input edge of the mixing chamber can be made with a rounding 14, which reduces the hydraulic resistance.

 With a large level of filling of the container 15 (Fig. 7 ... 13) with liquid, for example, in apparatus for growing microorganisms, a circulating cup 16 can be installed above the device (Fig. 5), as is usually done to create an air-lift effect. the cross section of the mixing chamber can be not only cylindrical, but also, for example, rectangular (Fig. 6).

 The gas supply to the device can be carried out both through the side wall of the tank 15, and from above (Fig. 7, 8). In the latter case, especially with small dimensions of the tank, and therefore the device, the latter can be easily removable portable.

 With the large dimensions of the tank 15, it is advisable to place several devices in it, which can be both with a cylindrical mixing chamber 1 (Fig. 9), and with a rectangular (Fig. 10), in a single-tier (Fig. 9, 10) or (with a large the filling level of the container 15 with liquid) multi-tier (Fig. 11) performance. In this case, for example, in yeast-growing apparatuses, it is possible to jointly arrange devices with other types of aeration devices, for example, tubular devices 17 (Fig. 12), as well as heat exchangers 18, for example, panel-type devices (Fig. 13), which improves the heat and mass transfer characteristics of the apparatus for due to turbulization of the flow near the heat-removing surfaces.

 The operation of the device for saturation with gas and mixing the liquid in the tank is as follows. In accordance with the technological scheme of the process in the tank, the gas enters the gas supply pipe 4 and then into the chamber 5 for supplying gas. From here, through the openings 3 of the wall 2, a part of the gas flows into the direct-flow mixing chamber 1 in the form of bubbles (during the implementation of the bubble regime of outflow) or flocks (in the jet mode). Gas bubbles emerging from the openings or formed after dispersion of the jets in the mixing chamber rise and create an ejection effect, as a result of which the liquid is sucked from below into the mixing chamber 1, where it is intensively mixed with gas. Moreover, as shown by experiments, the efficiency of ejection and mixing in the jet mode of flow is higher than in the bubble mode, and most importantly, the central mixing chamber ensures (see above) high quality mixing. The resulting gas-liquid jet, expanding, flows out of the mixing chamber (cylindrical shape - Fig. 1, with a cylindrical impermeable outlet section 11 - Fig. 2, with a diffuser impermeable outlet section 12 - Fig. 3, with a diffuser permeable outlet section 13 - Fig. 4 ) directly into the container (Fig. 1, 7 ... 13) or into the circulation cup 16 (Fig. 5), intensively turbulizing the overlying layers of liquid. At some distance, the jet is dispersed. As a result, over the device (Fig. 1, 5, 7, 8) or devices (Fig. 9 ... 13), an extensive zone of intensive mixing of gas with liquid and saturation of the liquid with gas is formed, and around it (them) - zone (s) recycling.

 At the same time, part of the gas from the chamber 5 flows through the openings 7, forming (see Fig. 1) an upward flow of gas bubbles near the outer side wall of the box 6, which, in addition to the obvious saturation of the liquid with gas, contributes (see above) to the dispersion of the gas-liquid jet from the mixing chamber, preventing the formation of large conglomerates of gas bubbles at the free boundary of the jet. This effect, if necessary, can be enhanced by performing the upper end wall perforated with holes 9.

Claims (4)

 1. DEVICE FOR GAS SATURATION AND MIXING OF LIQUID IN A TANK, including a mixing chamber, direct-flow towards the upper hemisphere of space, with a perforated wall for introducing gas and a gas supply pipe, characterized in that the device is equipped with an additional gas supply chamber made in the form of a box covering outside the main chamber, the cavity of the duct is in communication with the gas supply pipe, and its outer side wall is made of perforated openings for gas outlet.  2. The device according to claim 1, characterized in that the dimensions of the perforation holes are made decreasing along the length of the chambers in the direction of the upward flow.  3. The device according to claim 1, characterized in that the upper end wall of the duct is perforated with openings for gas outlet.  4. The device according to claim 1, characterized in that the duct has drainage holes for draining the liquid.

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