A boiler and an atmospheric pressure low-temperature distillation system having the boiler

Abstract

The present invention discloses a boiling device and a system having the boiling device. Among them, the boiling device at least includes a gas storage chamber and a microbubble generator. The gas outlet end of the gas storage chamber is fluidly connected to the gas inlet end of the microbubble generator, and the gas outlet end of the microbubble generator is arranged below the liquid level. In the present invention, the boiling device can not only ensure that it can be used for any long time without failure, but also can be reused and has strong versatility.

Description

Technical Field

[0001] The present invention relates to the technical field of instrument and equipment. Specifically, it is a boiler and an atmospheric pressure low-temperature distillation system having the boiler. Background Art

[0002] Theoretically, when a liquid is heated to its boiling point and its vapor pressure equals the ambient pressure, the liquid can boil and its temperature remains at the boiling point without rising. However, in practice, the liquid being heated often exhibits the phenomenon of "bumping": that is, the liquid cannot boil stably and continuously at its boiling point; on the contrary, when the temperature of the liquid has reached the boiling point, it still does not boil, and the temperature of the liquid continues to rise and exceeds the boiling point (commonly known as the superheating phenomenon of the liquid), and then a sudden explosive boiling phenomenon will occur at a certain moment, which is called bumping. The bumping phenomenon is very harmful in chemical experiments and chemical production, and the fundamental reason for causing bumping is the lack of vaporization centers in the system.

[0003] The traditional method to solve bumping is to add zeolite to the system. Zeolite is usually composed of porous solid particles. Since it contains a large number of micropores and the pores are filled with air, when heated, the air in the micropores expands and overflows from the micropores to generate tiny bubbles (i.e., vaporization centers), so that the liquid can vaporize and boil smoothly at the boiling point, avoiding the occurrence of the bumping phenomenon.

[0004] However, the traditional zeolite has the following several disadvantages:

[0005] 1) It will gradually become ineffective after being used for a period of time. As the air adsorbed in the micropores of the zeolite continuously overflows and gradually decreases during the boiling process, the effectiveness of the zeolite will decline accordingly; when it is completely exhausted, the zeolite becomes ineffective.

[0006] 2) It may introduce pollutants into the reaction system. Depending on the stability of the material used to manufacture the zeolite and the content of impurities, if used improperly, it may cause the reactants to be contaminated.

[0007] 3) Zeolite is usually disposable and is discarded after use, and is not suitable for recycling. Therefore, it is not environmentally friendly. Summary of the Invention

[0008] For this reason, the technical problem to be solved by the present invention is to provide a boiler and a system having the boiler, wherein the boiler can not only ensure that it can be used for any long time without becoming ineffective, but also can be reused and has strong versatility.

[0009] To solve the above technical problems, the present invention provides the following technical solutions:

[0010] A boiling device, at least comprising a gas storage chamber and a microbubble generator, the gas outlet end of the gas storage chamber is fluidly connected to the gas inlet end of the microbubble generator, and the gas outlet end of the microbubble generator is arranged below the liquid level.

[0011] For the above-mentioned boiling device, the microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber.

[0012] For the above-mentioned boiling device, an inflation valve is provided at the gas inlet end of the gas storage chamber.

[0013] For the above-mentioned boiling device, a gas guide pipe is provided on the gas storage chamber, and the gas inlet end of the microbubble generator is fluidly connected to the gas outlet end of the gas guide pipe.

[0014] For the above-mentioned boiling device, the shape of the gas storage chamber is not limited to spherical, cylindrical and conical.

[0015] For the above-mentioned boiling device, at least 10% of the gas guide holes on the orifice plate of the gas outlet end of the microbubble generator are special-shaped gas guide holes. The special-shaped gas guide holes are conical holes with the aperture gradually shrinking along the gas flow direction, and a flow retarder is provided on the inner wall of the gas outlet end of the special-shaped gas guide hole. The surface of the flow retarder facing the axis of the special-shaped gas guide hole is an arc surface coaxial with the special-shaped gas guide hole.

[0016] A system with the above-mentioned boiling device, comprising a boiling device, a reaction kettle and a condenser tube. The boiling device comprises a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber. When the boiling device is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the liquid reaction medium in the reaction kettle. The condenser tube is provided on the reaction kettle.

[0017] A system with the above-mentioned boiling device, comprising a boiling device, a reaction kettle, a condenser, a distillate collection tank, an air pump, a steam pipe, a carrier gas return pipe, a pressure relief valve, a gas replenishing valve and a carrier gas storage tank. The boiling device comprises a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber. When the boiling device is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the kettle liquid in the reaction kettle. The gas replenishing valve is provided on the pipeline between the gas outlet end of the carrier gas storage tank and the gas inlet end of the reaction kettle. The pressure relief valve is provided on the reaction kettle. The steam output end of the reaction kettle is fluidly connected to the steam input end of the condenser through the steam pipe. The distillate output end of the condenser is fluidly connected to the distillate inlet end of the distillate collection tank. The gas outlet end of the condenser is fluidly connected to the gas inlet end of the gas storage chamber through the air pump and the carrier gas return pipe.

[0018] The system with the above-mentioned boiler includes a boiler, a reaction kettle, a condenser, a distillate collection tank, an air pump, a carrier gas reflux pipeline, a pressure relief valve, a gas supply valve, a carrier gas storage tank, a rectification device, a distillate reflux pipeline and a proportional shunt valve. The boiler includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is in fluid communication with the inside of the gas storage chamber. When the boiler is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the inner kettle liquid in the reaction kettle. The gas supply valve is arranged on the pipeline between the gas outlet end of the carrier gas storage tank and the gas inlet end of the reaction kettle. The pressure relief valve is arranged on the reaction kettle. The steam output end of the reaction kettle is in fluid communication and connection with the steam input end of the condenser through the rectification device and the steam pipeline. The proportional shunt valve is arranged on the pipeline between the distillate output end of the condenser and the distillate inlet end of the distillate collection tank. The shunt valve is in fluid communication with the distillate reflux end of the rectification device through the distillate reflux pipeline. The gas outlet end of the condenser is in fluid communication with the gas inlet end of the gas storage chamber through the air pump and the carrier gas reflux pipeline.

[0019] The system with the above-mentioned boiler includes a boiler, a reaction kettle, a condenser, a distillate collection tank, an air pump, a carrier gas reflux pipeline, a pressure relief valve, a gas supply valve, a carrier gas storage tank, a rectification device, a distillate reflux pipeline, a first proportional shunt valve, a second proportional shunt valve, a kettle liquid reflux heater, a kettle liquid reflux pipeline and a kettle liquid storage tank. The boiler includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is in fluid communication with the inside of the gas storage chamber. When the boiler is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the inner kettle liquid in the reaction kettle. The first proportional shunt valve is arranged on the pipeline between the liquid inlet end of the kettle liquid storage tank and the liquid outlet end of the reaction kettle. The first shunt valve is in fluid communication with the kettle liquid reflux inlet end of the reaction kettle through the kettle liquid reflux pipeline and the kettle liquid reflux heater. The steam outlet end of the reaction kettle is in fluid communication with the steam inlet end of the rectification device. The steam outlet end of the rectification device is in fluid communication with the steam inlet end of the condenser through the steam pipeline. The second proportional shunt valve is arranged on the pipeline between the distillate output end of the condenser and the distillate inlet end of the distillate collection tank. The second proportional shunt valve is in fluid communication with the distillate reflux end of the rectification device through the distillate reflux pipeline. The gas supply valve is arranged on the pipeline between the gas outlet end of the carrier gas storage tank and the gas inlet end of the reaction kettle. The pressure relief valve is arranged on the reaction kettle. The gas outlet end of the condenser is in fluid communication with the gas inlet end of the gas storage chamber through the air pump and the carrier gas reflux pipeline.

[0020] The technical solution of the present invention has achieved the following beneficial technical effects:

[0021] The ebullator in the present invention is designed to address the above-mentioned drawbacks of traditional zeolites. It can not only ensure effective use for an arbitrarily long time without failure, but also be reused and has strong versatility. In addition, the device has the advantages of simple structure, easy processing, and the gas used in the vaporization center can be replaced at will according to actual needs (for example, for certain chemical reactions sensitive to oxygen and water vapor, an appropriate inert gas can be filled in the ebullator). In some cases, by using a gas circulation pump device in combination, it is also possible to carry out distillation operations at temperatures below the boiling point (referred to as atmospheric pressure low-temperature distillation, the same below), achieving the effect of vacuum distillation under atmospheric pressure.

[0022] The ebullator in the present invention can be used in the production of biomass liquid fuels, such as in the fields of rapid pyrolysis, deacidification, and esterification of biomass, enabling low-boiling components to vaporize and separate at lower temperatures, reducing the energy consumption in the production of biomass liquid fuels. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of an ebullator in the present invention;

[0024] Figure 2 Schematic diagram of the structure of an ebullator in the present invention;

[0025] Figure 3 Schematic diagram of the structure of an ebullator in the present invention;

[0026] Figure 4 Schematic diagram of the structure of an ebullator in the present invention;

[0027] Figure 5 Physical diagram of an ebullator;

[0028] Figure 6 Axial structure schematic diagram of the special-shaped air guide holes on the orifice plate at the gas outlet end of a microbubble generator;

[0029] Figure 7 For Figure 6 A radial structure schematic diagram of the special-shaped air guide holes in

[0030] Figure 8 For Figure 6 A radial structure schematic diagram of the special-shaped air guide holes in

[0031] Figure 9 For Figure 6 A radial structure schematic diagram of the special-shaped air guide holes in

[0032] Figure 10 For Figure 6 A radial structure schematic diagram of the special-shaped air guide holes in

[0033] Figure 11Schematic structural diagram of the orifice plate at the gas outlet end of a microbubble generator;

[0034] Figure 12 Schematic structural diagram of a system with a boiler in the present invention;

[0035] Figure 13 Schematic structural diagram of a system with a boiler in the present invention;

[0036] Figure 14 Schematic structural diagram of a system with a boiler in the present invention

[0037] Figure 15 Schematic structural diagram of a distillation column;

[0038] Figure 16 Schematic structural diagram of a system with a boiler in the present invention.

[0039] In the figure, the reference numerals are as follows: 1 - gas storage chamber; 2 - microbubble generator, 2-1 - orifice plate, 2-2 - special-shaped air guide hole, 2-3 - stagnant flow block, 2-4 - linear air guide hole, 2-5 - composite structure air guide hole; 3 - inflation valve; 4 - reaction kettle; 5 - condenser tube, 6 - condenser; 7 - distillate collection tank; 8 - air pump; 9 - steam pipeline; 10 - carrier gas return pipeline; 11 - pressure relief valve; 12 - air supply valve; 13 - carrier gas storage tank; 14 - distillation column; 15 - distillate return pipeline; 16 - proportional shunt valve; 17 - feed inlet; 18 - discharge outlet; 19 - kettle liquid return heater; 20 - kettle liquid return pipeline; 21 - kettle liquid storage tank; a - standard ground glass stopper; b - distillation column tower body; c - tray; d - steam inlet; e - steam outlet. Detailed implementation manners

[0040] Example 1

[0041] As Figure 1 shown, the boiler in the present invention includes a gas storage chamber 1 and a microbubble generator 2. The gas outlet end of the gas storage chamber 1 is fluidly connected to the gas inlet end of the microbubble generator 2, and the gas outlet end of the microbubble generator 2 is arranged below the liquid level.

[0042] Among them, the microbubble generator 2 is arranged on the wall of the gas storage chamber 1 and is fluidly connected to the inside of the gas storage chamber 1. An inflation valve 3 is provided on the gas inlet end of the gas storage chamber 1, and the setting of the inflation valve 3 facilitates the inflation and cleaning of the gas storage chamber 1.

[0043] According to the actual use environment, a gas guide pipe can be provided on the gas storage chamber 1, and the gas inlet end of the microbubble generator 2 is fluidly connected to the gas outlet end of the gas guide pipe. In actual use, the microbubble generator 2 can be extended to different parts of the liquid by using the gas guide pipe to increase the uniformity of boiling, such asFigure 4 As shown, this enables people to set the number of the microbubble generators 2 according to the different boiling requirements in different regions.

[0044] And according to the actual use environment, the shape of the gas storage chamber 1 is made into a corresponding shape, not limited to spherical, cylindrical and conical shapes, such as Figure 2 the curved shape shown.

[0045] In order to improve the efficiency of the boiler, a plurality of the microbubble generators 2 can be arranged on the wall of the gas storage chamber 1, as Figure 3 shown.

[0046] In this embodiment, the gas storage chamber 1 is a space with a certain physical boundary, a certain volume and capable of storing gas, such as a glass tube, a stainless steel tube, a hollow glass sphere, etc. Generally, there is no special requirement for the volume size of the gas storage chamber 1. But in reality, for the convenience of operation, the volume of the gas storage chamber 1 is often smaller than the volume of the reaction kettle 4, for example, it can be one tenth, one hundredth, one thousandth, one ten - thousandth, etc. of the volume of the reaction kettle 4. For example, for a reaction kettle 4 with a volume of 5000 milliliters, a gas storage chamber 1 with a volume of 0.5 milliliters, 1 milliliter, 5 milliliters, 10 milliliters, 20 milliliters can all achieve good results.

[0047] Figure 5 Shown is a physical diagram of a boiler suitable for general chemical laboratories. Among them, the gas storage chamber 1 of the boiler is a glass tube with a diameter of 10 mm; the microbubble generator 2 is a sintered filter core with a pore diameter of 30 - 50 microns; the piston of the inflation valve 3 is made of polytetrafluoroethylene; in order to facilitate the use in cooperation with standard - caliber glass instruments (such as round - bottom flasks with standard calibers), a standard ground - glass stopper a is also arranged on the upper part of the gas storage chamber 1.

[0048] Among them, the microbubble generator 2 can be composed of porous materials, such as porous materials made of natural or synthetic fibers, ceramic filter elements or membranes (sheets), stainless steel filter elements or membranes (sheets), etc.; the microbubble generator 2 is located at the lower end of the gas storage chamber 1 and is placed below the liquid level during actual use, as Figure 12 shown.

[0049] In order to better simulate the real boiling phenomenon and improve the boiling effect at the same time, special - shaped air guide holes are added to the porous material, or a hole plate 2 - 1 with the special - shaped air guide holes 2 - 2 is directly processed. The structure of the special - shaped air guide holes is as Figures 6 - 10As shown. In this embodiment, preferably, the microbubble generator is a microbubble generator with an orifice plate structure at the gas outlet end. The orifice plate at the gas outlet end of the microbubble generator is an artificially processed orifice plate 2-1, and at least 10% of the air guide holes on the orifice plate at the gas outlet end of the microbubble generator are special-shaped air guide holes 2-2. The special-shaped air guide holes 2-2 are conical holes with a gradually decreasing aperture along the gas flow direction, and a stagnant flow block 2-3 is provided on the inner wall of the gas outlet end of the special-shaped air guide holes 2-2. The surface of the stagnant flow block 2-3 facing the axis of the special-shaped air guide holes 2-2 is an arc surface coaxial with the special-shaped air guide holes 2-2. In actual production, the stagnant flow block 2-3 and the orifice plate 2-1 are integrally formed. Among them, Figure 7 and Figure 9 the special-shaped air guide holes 2-2 in Figure 8 and Figure 10 are applicable to liquids with relatively high viscosities, Figure 7 and Figure 8 the special-shaped air guide holes 2-2 in Figure 9 and Figure 10 are applicable to liquids with relatively low viscosities, Figure 7 and Figure 8 the special-shaped air guide holes 2-2 in Figure 7 and Figure 8 are applicable to liquids that require violent boiling. When heating the gas in the gas storage chamber 1, the bubble escape speed from the special-shaped air guide holes 2-2 in Figure 9 and Figure 10 is faster than that of the bubbles escaping from the conventional air guide holes with the same aperture. The bubbles escaping from the special-shaped air guide holes 2-2 in Figure 7 and Figure 8 can carry some of the bubbles escaping from the air guide holes with the same aperture and quickly float upward, forming a boiling effect. Bubbles with different floating speeds are conducive to the formation of steam from the inside of the liquid into the bubbles, thereby improving the boiling effect. While Figure 9 and Figure 10 the special-shaped air guide holes 2-2 in

[0050] will limit the bubble escape speed, that is, a relatively flat end face is used to form a large contact surface with the bubble wall, thereby generating a large adsorption force to limit the bubble escape speed.

[0050] For liquids with viscosities similar to that of water and with a relatively large difference in boiling points between different components (for example, the boiling point difference is more than 10 °C), the orifice plate at the gas outlet end of the microbubble generator 2 can adopt the orifice plate 2-1 as shown in Figure 11 . The orifice plate is provided with a linear air guide hole 2-4 and a composite structure air guide hole 2-5 with a conical hole at the gas outlet end. This structure can use the conical hole to generate large bubbles, which is conducive to the evaporation of the component with a lower boiling point into the bubbles and promotes the floating of the bubbles.

[0051] Embodiment 2

[0052] As shown in Figure 12As shown in the figure, in this embodiment, the system with the above-mentioned boiling device is a reflux chemical reaction system, including a boiling device, a reaction kettle 4 and a condenser 5. The boiling device includes a gas storage chamber 1 and a microbubble generator 2. The microbubble generator 2 is arranged on the wall of the gas storage chamber 1 and is in fluid communication with the inside of the gas storage chamber 1. When the boiling device is assembled with the reaction kettle 4, the microbubble generator 2 is arranged below the liquid reaction medium level in the reaction kettle 4. The condenser 5 is arranged on the reaction kettle 4.

[0053] Place the reactants in the reaction kettle 4; the microbubble generator 2 on the boiling device installed on the reaction kettle 4 extends below the liquid level. During normal use, the inflation valve 3 is closed; when heating the liquid, the gas in the gas storage chamber 1 expands due to heat and overflows from the micropores of the microbubble generator 2 to form tiny bubbles. The microbubble generator 2 acts as a vaporization center; when the liquid temperature reaches the boiling point, the liquid boils stably through the vaporization center, avoiding the occurrence of bumping boiling. The steam rises and enters the condenser 5 and is condensed into a liquid in the condenser 5, and then returns to the reaction kettle 4 under the action of gravity, avoiding the loss of the solvent.

[0054] The pore diameter of the microbubble generator 2 can vary within a wide range according to specific circumstances, for example, it can vary within the order of magnitude from nanometers to millimeters. However, for the convenience of cleaning, the pore diameter should not be too small. Generally, it is recommended to select a pore diameter between 0.01 - 1000 microns, preferably between 10 - 30 microns, 30 - 50 microns, etc.

[0055] Generally, there are no special requirements for the size of the microbubble generator 2, and it can be flexibly adjusted (increased or decreased) according to the volume of the reaction kettle 4 and the desired distillation rate or the optimal value can be determined through experiments. For example, a boiling device made of a sand chip with a diameter of about 1 cm and a pore diameter of 30 - 50 microns and a glass tube with an inner diameter of 10 mm, as Figure 12 shown, can be used for glass round-bottom flasks with a volume of 250 ml to 10000 ml to achieve ideal effects.

[0056] When the volume of the reaction system increases or the evaporation rate needs to be accelerated, the size of the microbubble generator 2 can be considered to be increased accordingly. For example, a sand core with a larger size (such as a diameter of 1.5 cm, 2 cm or 2.5 cm, etc.) can be selected, or multiple microbubble generators 2 can be installed on the same boiling device ( Figure 3 、 Figure 4 ), or multiple boiling devices can be installed in the same reaction kettle 4.

[0057] In practice, it is found that the described ebullator can work continuously for a long time, such as continuously working for 24 hours, 48 hours, etc., without failure. In some cases, if the heating needs to be stopped for a period of time during the reaction, before resuming heating next time, only need to supplement gas to the gas storage chamber 1 through the gas filling valve 3 and discharge the liquid sucked back into the gas storage chamber 1, then the ebullator can resume normal operation.

[0058] Embodiment 3

[0059] As Figure 13 shown, in this embodiment, the system with the above ebullator is an atmospheric pressure low-temperature distillation system, including an ebullator, a reaction kettle 4, a condenser 6, a distillate collection tank 7, an air pump 8, a steam pipeline 9, a carrier gas reflux pipeline 10, a pressure relief valve 11, a gas supplement valve 12 and a carrier gas storage tank 13. The ebullator includes a gas storage chamber 1 and a microbubble generator 2. The microbubble generator 2 is arranged on the wall of the gas storage chamber 1 and is in fluid communication with the inside of the gas storage chamber 1. When the ebullator is assembled with the reaction kettle 4, the microbubble generator 2 is arranged below the liquid level of the liquid in the inner kettle of the reaction kettle 4. The gas supplement valve 12 is arranged on the pipeline between the gas outlet end of the carrier gas storage tank 13 and the gas inlet end of the reaction kettle 4. The pressure relief valve 11 is arranged on the reaction kettle 4. The steam output end of the reaction kettle 4 is in fluid communication connection with the steam input end of the condenser 6 through the steam pipeline 9. The distillate output end of the condenser 6 is in fluid communication connection with the distillate inlet end of the distillate collection tank 7. The gas outlet end of the condenser 6 is in fluid communication connection with the gas inlet end of the gas storage chamber 1 through the air pump 8 and the carrier gas reflux pipeline 10.

[0060] First, add the liquid to be distilled and a selected carrier gas, such as air, nitrogen, argon, etc., into the Figure 13 sealed system. Any suitable gas can also be selected according to the actual situation. Then heat the reaction kettle 4 to a predetermined temperature (this temperature is the pre-set distillation temperature, lower than the normal boiling point of the liquid), and control the temperature within a predetermined range through a temperature control device. During the heating process, since the pressure in the system will increase with the increase of temperature, when the system pressure exceeds a set critical value, the pressure relief valve 11 automatically opens to exhaust and relieve pressure, so that the system pressure returns to the normal range.

[0061] When the system temperature reaches the set temperature and stabilizes, open the inflation valve 3 and start the air pump 8. At this time, the carrier gas is pushed by the air pump 8 through the inflation valve 3 into the gas storage chamber 1, and then a continuous bubble stream is generated through the microbubble generator 2 and enters the liquid to be distilled; the bubbles then float in the liquid, and at the same time, in this process, they fully contact the liquid, and the liquid evaporates into the bubbles until its vapor partial pressure is equal to its saturated vapor pressure. In this process, the liquid and the vapor reach a sufficient gas-liquid equilibrium, and finally a mixed gas stream of "carrier gas + vapor" enters the condenser 6 through the steam pipeline 9; in the condenser 6, the vapor is condensed, restored to the liquid state, and flows into the distillate collection tank 7 under the action of gravity; while the carrier gas re-enters the boiler through the carrier gas return pipeline 10 under the action of the air pump 8 and works in a cycle.

[0062] In order to better process the liquid to be distilled, in this embodiment, the carrier gas can be preheated before entering the boiler, and the temperature of the carrier gas is brought to the same temperature as the liquid in the reaction kettle 4, and the carrier gas return pipeline 10 is first bypassed to the bottom of the reaction kettle 4 and brought into full contact with it before being connected to the boiler to achieve thermal equilibrium. Therefore, the carrier gas has been heated to the same temperature as the liquid in the kettle before entering the boiler.

[0063] Assume that the atmospheric pressure is P0, the saturated vapor pressure of the liquid at the set distillation temperature T1 is P1, and the carrier gas flow rate is R0; then the pressure of the carrier gas before entering the microbubble generator 2 is approximately P z ≈P0 (neglecting the small pressure difference generated by the liquid column and the additional pressure required for the gas to pass through the microbubble generator 2); when the bubbles overflow from the liquid phase, the sum of the partial pressure P z ’ of the carrier gas and the liquid vapor pressure P1 in the mixed gas should be equal to the atmospheric pressure P0, that is:

[0064] P z ’ + P1 = P0 (1)

[0065] In the mixed gas, the relative flow rates of the carrier gas and the vapor should be proportional to their respective partial pressures, that is:

[0066] P z ’ / P1 = R0 / R1 (2)

[0067] If the flow rate (R0) of the carrier gas is kept constant (which can be achieved by controlling the flow rate of the air pump 8), then the flow rate R1 of the liquid vapor (i.e., the distillation rate of the liquid) can be estimated by the above formula. Substituting equation (1) into equation (2) and rearranging, we get:

[0068] R1 = R0 P1 / (P0 - P1) (3)

[0069] It can be seen that the distillation speed can be controlled by adjusting the flow rate of the air pump 8. Since controlling the flow rate of the air pump 8 is much simpler and easier than controlling and stabilizing the vacuum degree, replacing the traditional vacuum distillation technology with the above-mentioned atmospheric pressure low-temperature distillation technology can achieve the purposes of simplifying equipment and operation, reducing costs, and environmental protection and energy conservation.

[0070] The said atmospheric pressure low-temperature distillation system is applicable to intermittent distillation operations, that is, the distillation process must be carried out in batches: that is, only a certain amount of materials can be added to the reaction kettle 4 each time during distillation. When the distillation is over, the system is closed to let it cool down. During the cooling process, the system pressure gradually drops. When it drops to a preset critical value, the air supply valve 12 automatically opens to supply air until the system pressure returns to the atmospheric pressure. When the system is completely cooled, the distillate collected in the distillate collection tank 7 and the bottom product remaining in the reaction kettle 4 are taken out separately, and then a new round of feeding and distillation operations can be carried out.

[0071] When the atmospheric pressure low-temperature distillation system in this embodiment is used for the concentration and purification of tea polyphenol extract, Figure 13 add the tea polyphenol extract and fill nitrogen as the carrier gas into the sealed system shown; heat the reaction kettle 4 to 40 - 45 °C, then open the gas charging valve 3 and start the air pump 8. At this time, the carrier gas enters the gas storage chamber 1 through the gas charging valve 3 under the push of the air pump 8, and then a continuous bubble flow is generated through the microbubble generator 2 and enters the tea polyphenol extract. The bubbles then float in the liquid, and at the same time, in this process, they fully contact the liquid. The solvent in the extract continuously evaporates into the bubbles until its vapor pressure is equal to its saturated vapor pressure.

[0072] During this process, a sufficient gas-liquid equilibrium is reached between the solvent and the vapor in the extract. Finally, a mixed gas flow of "nitrogen + solvent vapor" passes through the steam pipeline 9 and enters the condenser 6; in the condenser 6, the solvent vapor is condensed, returns to the liquid state, and flows into the distillate collection tank 7 under the action of gravity; while the nitrogen re-enters the boiling vessel through the carrier gas return pipeline 10 under the action of the air pump 8 and circulates; because the volatility of tea polyphenols is very low, they are left in the kettle. The concentrated crude tea polyphenol product can obtain a tea polyphenol solid product with higher purity after freeze-drying.

[0073] Example 4

[0074] As Figure 14As shown in the figure, in this embodiment, the system with the above-mentioned boiling device is an atmospheric pressure low-temperature rectification system, which includes a boiling device, a reaction kettle 4, a condenser 6, a distillate collection tank 7, an air pump 8, a carrier gas reflux pipeline 10, a pressure relief valve 11, a gas replenishing valve 12, a carrier gas storage tank 13, a rectification device, a distillate reflux pipeline 15 and a proportional shunt valve 16. The boiling device includes a gas storage chamber 1 and a microbubble generator 2. The microbubble generator 2 is arranged on the wall of the gas storage chamber 1 and is in fluid communication with the inside of the gas storage chamber 1. When the boiling device is assembled with the reaction kettle 4, the microbubble generator 2 is arranged below the liquid level of the inner kettle liquid in the reaction kettle 4. A gas replenishing valve 12 is arranged on the pipeline between the gas outlet end of the carrier gas storage tank 13 and the gas inlet end of the reaction kettle 4. A pressure relief valve 11 is arranged on the reaction kettle 4. The steam output end of the reaction kettle 4 is in fluid communication with the steam input end of the condenser 6 through the rectification device and the steam pipeline 9. A proportional shunt valve 16 is arranged on the pipeline between the distillate output end of the condenser 6 and the distillate inlet end of the distillate collection tank 7. The shunt valve is in fluid communication with the distillate reflux end of the rectification device through the distillate reflux pipeline 15. The gas outlet end of the condenser 6 is in fluid communication with the gas inlet end of the gas storage chamber 1 through the air pump 8 and the carrier gas reflux pipeline 10. Among them, the rectification device is a rectification column 14, as Figure 15 shown.

[0075] Rectification technology can be understood as multiple distillations, and its core component is a rectification column or a rectification tower 14. In the rectification tower 14, the tower body b of the rectification tower is a long tubular column arranged vertically. Inside the column, multiple trays c are arranged horizontally. There are channels between adjacent trays c that allow steam and liquid to pass through. The bottom of the tower has a steam inlet d, and the top has a steam outlet e.

[0076] The working principle of the rectification tower 14 is as follows:

[0077] Suppose that the steam before entering the distillation column 14 contains equal amounts of component A and component B, and further suppose that the boiling point of A is lower than that of B. When the mixed steam enters from the bottom of the distillation column 14, it first contacts and exchanges heat with the bottommost tray, causing part of the steam to be condensed and remain on the tray, while the uncondensed steam continues to rise; since the boiling point of B is higher than that of A, it can be predicted that the content of B in the condensate on the tray will be greater than that of A; on the contrary, the content of A in the continuously rising steam will be greater than that of B. In other words, after partial condensation on the tray, the content of the low-boiling component in the steam increases. As the steam continues to rise along the distillation column 14, it is partially condensed each time it passes through a tray, and the content of A in the steam increases each time. Therefore, as the steam rises in the column, the content of component A in the steam after multiple partial condensations will become higher and higher, achieving the purpose of separating components A and B. It can be predicted that the more trays there are and the more times the steam is partially condensed, the higher the content of A in the steam distilled at the top of the column. Therefore, the separation efficiency of the distillation column 14 is often measured by the number of trays, that is, the larger the number of trays, the higher the separation efficiency.

[0078] The operating steps and working principle of the atmospheric pressure low-temperature distillation system are as follows:

[0079] First, add the liquid to be distilled and a selected carrier gas, such as air, nitrogen, argon, etc. (any suitable gas can be selected according to the actual situation) into the Figure 14 sealed system. Then heat the reaction kettle 4 to a predetermined temperature (this temperature is preset and lower than the normal boiling point of the liquid), and control the temperature within a predetermined range through a temperature control device; during the heating process, since the pressure in the system will increase with the increase in temperature, when the system pressure exceeds a preset critical value, the pressure relief valve 11 automatically opens to exhaust and relieve pressure, so that the system pressure returns to the set range.

[0080] When the system temperature reaches the set temperature and stabilizes, open the inflation valve 3 and start the air pump 8. At this time, the carrier gas enters the gas storage chamber 1 through the inflation valve 3 under the push of the air pump 8, and then generates a continuous bubble flow through the microbubble generator 2 and enters the liquid in the reaction kettle 4 (abbreviated as "kettle liquid"); the bubbles then float in the kettle liquid, and at the same time, they are fully in contact with the kettle liquid during this process. The volume of the bubbles continuously grows as the components in the kettle liquid evaporate into the bubbles until its vapor partial pressure is equal to their respective saturated vapor pressures. During this process, the kettle liquid and the vapor reach gas-liquid equilibrium, and finally a mixed gas flow of "carrier gas + vapor" enters the rectification column 14 from the lower part of the rectification column 14. During the upward process along the rectification column 14, the vapor undergoes multiple partial condensations on the trays, and the concentration of the low-boiling components in the vapor becomes higher and higher. Finally, the content of the low-boiling components in the vapor distilled out at the top of the column reaches the maximum value; the distilled vapor enters the condenser 6 through the vapor pipeline 9, is condensed in the condenser 6, returns to the liquid state, and flows through a proportional shunt valve 16 under the action of gravity. Part of it enters the distillate collection tank 7, and the other part returns to the top of the rectification column 14; while the carrier gas re-enters the boiler through the carrier gas return pipeline 10 under the action of the air pump 8 and circulates. As the low-boiling components are distilled out and collected in the distillate collection tank 7, the content of the high-boiling components in the kettle liquid becomes higher and higher, achieving the purpose of separating mixtures with different boiling points.

[0081] In order to facilitate ensuring the stable state of the kettle liquid in the reaction kettle 4, thereby ensuring the stable steam production rate during the rectification process, the carrier gas has been preheated before entering the boiler to reach the same temperature as the liquid in the reaction kettle 4, and the carrier gas return pipeline 10 bypasses to the bottom of the reaction kettle 4 and is in full contact with it and reaches thermal equilibrium before connecting to the boiler. Therefore, the carrier gas has been heated to the same temperature as the liquid in the kettle before entering the boiler.

[0082] The atmospheric pressure low-temperature rectification system is suitable for intermittent rectification operations, that is, the rectification process must be carried out batch by batch: that is, only a certain amount of material can be added to the reaction kettle 4 each time during distillation. When the distillation is over, the system is closed and allowed to cool; during the cooling process, the system pressure gradually decreases. When it drops to the set critical value, the air replenishing valve 12 automatically opens to replenish air until the system pressure returns to atmospheric pressure; finally, the distillate collected in the distillate collection tank 7 and the kettle liquid remaining in the reaction kettle 4 are taken out separately, and then the next round of feeding and rectification operations can be carried out.

[0083] When using the atmospheric pressure low-temperature rectification system in this embodiment to recycle and reuse the waste liquid of high-performance liquid chromatography (HPLC), Figure 14Into the sealed system shown, add the HPLC waste liquid to be distilled, which contains 50% methanol and 50% water, and fill it with air as the carrier gas; heat the reaction kettle 4 to 40 - 45 °C, then open the gas filling valve 3 and start the air pump 8. At this time, the carrier gas is pushed by the air pump 8 to enter the gas storage chamber 1 through the gas filling valve 3, and then a continuous bubble stream is generated through the microbubble generator 2 and enters the liquid to be distilled. The bubbles then float in the liquid and fully contact the liquid during this process. Water and methanol evaporate into the bubbles until their partial pressures are equal to their respective saturated vapor pressures.

[0084] Since the boiling point of methanol (64.5 °C) is lower than that of water (100 °C), the content of methanol in the bubbles is higher than that of water vapor. The mixed vapor then enters the rectification column driven by the carrier gas and is partially condensed on each tray in the rectification column to reach a new gas-liquid equilibrium again; the content of methanol in the mixed gas after multiple gas-liquid equilibriums becomes higher and the water content becomes lower; the mixed gas coming out from the top of the rectification column then enters the condenser 6 and is cooled. The methanol vapor (and a small amount of residual water vapor) is cooled and then shunted through the proportional shunt valve 16. Part of it flows into the distillate storage tank, while the other part flows back to the top of the rectification column 14 through the reflux pipeline; the air carrier gas is pushed by the air pump 8 and re-enters the boiler through the carrier gas reflux pipeline 10 to cycle and work.

[0085] A significant advantage of recovering methanol from HPLC waste liquid using the above atmospheric pressure and low temperature rectification technology is that the content of solid residues in methanol is greatly reduced.

[0086] Example 5

[0087] As Figure 16As shown in the figure, the system with the above-mentioned boiler in this embodiment is an atmospheric pressure low-temperature continuous distillation system, including a boiler, a reaction kettle 4, a condenser 6, a distillate collection tank 7, an air pump 8, a carrier gas reflux pipeline 10, a pressure relief valve 11, a gas supply valve 12, a carrier gas storage tank 13, a distillation device, a distillate reflux pipeline 15, a first proportional shunt valve 16, a second proportional shunt valve 16, a kettle liquid reflux heater 19, a kettle liquid reflux pipeline 20 and a kettle liquid storage tank 21. The boiler includes a gas storage chamber 1 and a microbubble generator 2. The microbubble generator 2 is arranged on the wall of the gas storage chamber 1 and is in fluid communication with the inside of the gas storage chamber 1. When the boiler is assembled with the reaction kettle 4, the microbubble generator 2 is arranged below the liquid level of the kettle liquid in the reaction kettle 4. A first proportional shunt valve 16 is arranged on the pipeline between the liquid inlet end of the kettle liquid storage tank 21 and the liquid outlet end of the reaction kettle 4. The first shunt valve is in fluid communication and connected with the kettle liquid reflux inlet end of the reaction kettle 4 through the kettle liquid reflux pipeline 20 and the kettle liquid reflux heater 19. The steam outlet end of the reaction kettle 4 is in fluid communication with the steam inlet end of the distillation device. The steam outlet end of the distillation device is in fluid communication with the steam inlet end of the condenser 6 through the steam pipeline 9. A second proportional shunt valve 16 is arranged on the pipeline between the distillate output end of the condenser 6 and the distillate inlet end of the distillate collection tank 7. The second proportional shunt valve 16 is in fluid communication with the distillate reflux end of the distillation device through the distillate reflux pipeline 15. A gas supply valve 12 is arranged on the pipeline between the gas outlet end of the carrier gas storage tank 13 and the gas inlet end of the reaction kettle 4. A pressure relief valve 11 is arranged on the reaction kettle 4. The gas outlet end of the condenser 6 is in fluid communication with the gas inlet end of the gas storage chamber 1 through the air pump 8 and the carrier gas reflux pipeline 10.

[0088] In Figure 16 the shown atmospheric pressure low-temperature continuous distillation system, a feed inlet 17 is arranged in the middle of the distillation column 14 and a discharge outlet 18 is arranged at the bottom of the reaction kettle 4. Its working principle is similar to that of Figure 14 the system: After the preheated material enters the distillation column 14, the components with lower boiling points vaporize, and the steam rises with the carrier gas; the components with higher boiling points are in a liquid state and flow towards the reaction kettle 4 under the action of gravity. In this process, when the upward steam encounters the upper tray, the steam is partially condensed, resulting in a further increase in the low-boiling components in the steam; after repeating this many times, the concentration of the low-boiling components in the distillate steam reaching the top of the tower reaches the maximum value; the steam enters the condenser 6 and is condensed into a liquid (distillate); the distillate passes through the proportional shunt valve 16, and a part enters the storage tank, and the other part returns to the top of the distillation column 14.

[0089] Similarly, when the liquid flowing downward reaches the tray below the feed inlet 17, the liquid is heated and partially evaporated (since the temperature at the lower end of the column is higher than that at the upper end of the column); because the low-boiling components are more likely to evaporate, the content of the high-boiling components remaining in the liquid phase increases accordingly; therefore, after the liquid flowing downward is heated and partially volatilized on the trays multiple times, the content of the high-boiling components becomes higher and higher; when it finally reaches the reaction kettle 4, the content of the high-boiling components reaches the maximum value; the kettle liquid enters the proportional shunt valve 16 from the bottom discharge port 18 for shunting, a part of it flows into the kettle liquid storage tank 21, and the other part is heated and then refluxed into the kettle. As long as the relative flow rates of the feed inlet 17 and the discharge port 18 and the shunt ratios of the two proportional shunt valves 16 are adjusted to maintain the liquid level stability in the reaction kettle 4, the device can achieve continuous rectification operation. The separated low-boiling components and high-boiling components can be continuously output without interruption.

[0090] When the systems in Examples 2 to 5 are used for the production of biomass liquid fuels, the bubbles generated by the boiling device can carry the low-boiling substances in the liquid out from the inside of the liquid, thereby realizing low-energy consumption operation in a certain link of the biomass liquid fuel production and reducing the production cost of the enterprise.

[0091] Obviously, the above examples are only for illustration purposes and are not intended to limit the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the claims of this patent application.

Claims

1. A boiler, characterized in that, It at least includes a gas storage chamber and a microbubble generator. The gas outlet end of the gas storage chamber is fluidly connected to the gas inlet end of the microbubble generator, and the gas outlet end of the microbubble generator is arranged below the liquid surface. At least 10% of the gas guide holes on the orifice plate at the gas outlet end of the microbubble generator are special-shaped gas guide holes. The special-shaped gas guide holes are conical holes with the aperture gradually decreasing along the gas flow direction, and there are flow retardation blocks on the inner wall of the gas outlet end of the special-shaped gas guide holes. The surface of the flow retardation block facing the central axis of the special-shaped gas guide hole is an arc surface coaxial with the special-shaped gas guide hole.

2. The boiler according to claim 1, characterized in that, The microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber.

3. The boiler according to claim 1, characterized in that, An inflation valve is provided at the gas inlet end of the gas storage chamber.

4. The boiler according to claim 1, characterized in that, A gas guide pipe is provided on the gas storage chamber, and the gas inlet end of the microbubble generator is fluidly connected to the gas outlet end of the gas guide pipe.

5. The boiler according to claim 1, characterized in that The shape of the gas storage chamber is not limited to spherical, cylindrical and conical.

6. A system having the boiler according to claim 1, characterized in that, It includes a boiler, a reaction kettle and a condenser tube. The boiler includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber. When the boiler is assembled with the reaction kettle, the microbubble generator is arranged below the liquid reaction medium surface in the reaction kettle. The condenser tube is provided on the reaction kettle.

7. A system having the boiler according to claim 1, characterized in that, It includes a boiler, a reaction kettle, a condenser, a distillate collection tank, an air pump, a steam pipe, a carrier gas return pipe, a pressure relief valve, a gas supplement valve and a carrier gas storage tank. The boiler includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the wall of the gas storage chamber and is fluidly connected to the inside of the gas storage chamber. When the boiler is assembled with the reaction kettle, the microbubble generator is arranged below the kettle liquid surface in the reaction kettle. The gas supplement valve is provided on the pipeline between the gas outlet end of the carrier gas storage tank and the gas inlet end of the reaction kettle. The pressure relief valve is provided on the reaction kettle. The steam output end of the reaction kettle is fluidly connected to the steam input end of the condenser through the steam pipe. The distillate output end of the condenser is fluidly connected to the distillate inlet end of the distillate collection tank. The gas outlet end of the condenser is fluidly connected to the gas inlet end of the gas storage chamber through the air pump and the carrier gas return pipe.

8. A system having the boiler according to claim 1, characterized in that, It includes a boiling device, a reaction kettle, a condenser, a distillate collection tank, an air pump, a carrier gas reflux pipeline, a pressure relief valve, a gas replenishing valve, a carrier gas storage tank, a rectification device, a distillate reflux pipeline and a proportional shunt valve. The boiling device includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the chamber wall of the gas storage chamber and is in fluid communication with the interior of the gas storage chamber. When the boiling device is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the liquid in the inner kettle of the reaction kettle. A gas replenishing valve is provided on the pipeline between the air outlet end of the carrier gas storage tank and the air inlet end of the reaction kettle. The reaction kettle is provided with the pressure relief valve. The steam output end of the reaction kettle is in fluid communication connection with the steam input end of the condenser through the rectification device and the steam pipeline. A proportional shunt valve is provided on the pipeline between the distillate output end of the condenser and the distillate inlet end of the distillate collection tank. The shunt valve is in fluid communication connection with the distillate reflux end of the rectification device through the distillate reflux pipeline. The air outlet end of the condenser is in fluid communication connection with the air inlet end of the gas storage chamber through the air pump and the carrier gas reflux pipeline.

9. A system having the boiler according to claim 1, characterized in that, It includes a boiling device, a reaction kettle, a condenser, a distillate collection tank, an air pump, a carrier gas reflux pipeline, a pressure relief valve, a gas replenishing valve, a carrier gas storage tank, a rectification device, a distillate reflux pipeline, a first proportional shunt valve, a second proportional shunt valve, a kettle liquid reflux heater, a kettle liquid reflux pipeline and a kettle liquid storage tank. The boiling device includes a gas storage chamber and a microbubble generator. The microbubble generator is arranged on the chamber wall of the gas storage chamber and is in fluid communication with the interior of the gas storage chamber. When the boiling device is assembled with the reaction kettle, the microbubble generator is arranged below the liquid level of the liquid in the inner kettle of the reaction kettle. A first proportional shunt valve is provided on the pipeline between the liquid inlet end of the kettle liquid storage tank and the liquid outlet end of the reaction kettle. The first shunt valve is in fluid communication connection with the kettle liquid reflux inlet end of the reaction kettle through the kettle liquid reflux pipeline and the kettle liquid reflux heater. The steam outlet end of the reaction kettle is in fluid communication connection with the steam inlet end of the rectification device. The steam outlet end of the rectification device is in fluid communication connection with the steam inlet end of the condenser through the steam pipeline. A second proportional shunt valve is provided on the pipeline between the distillate output end of the condenser and the distillate inlet end of the distillate collection tank. The second proportional shunt valve is in fluid communication connection with the distillate reflux end of the rectification device through the distillate reflux pipeline. A gas replenishing valve is provided on the pipeline between the air outlet end of the carrier gas storage tank and the air inlet end of the reaction kettle. The reaction kettle is provided with the pressure relief valve. The air outlet end of the condenser is in fluid communication connection with the air inlet end of the gas storage chamber through the air pump and the carrier gas reflux pipeline.

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