Cyclodextrin evaporation device system and preparation method thereof

Abstract

The invention provides a cyclodextrin evaporation device system and a preparation method thereof. The cyclodextrin evaporation device system comprises a multi-effect evaporation unit, a preheating unit, a material source, a steam source and a hot-pressing injection device, the material source is connected with the preheating unit, and the preheating unit is connected with the feeding end of the multi-effect evaporation unit through a feeding main pipe and further connected with the multi-effect evaporation unit through at least one heat exchange pipeline. The two ends of the hot-pressing jetting device are connected with the steam source and the multiple-effect evaporation unit correspondingly and used for providing primary steam for the hot-pressing jetting device. The multi-effect evaporation unit comprises at least two-effect falling film evaporation devices which are sequentially connected in the flowing direction of primary steam; and at least one falling film evaporation device is connected with the hot-pressing injection device through a waste heat return pipe and is used for guiding and sucking the generated secondary steam to the hot-pressing injection device. On the premise of fully considering the material properties, the cyclodextrin is subjected to multi-effect falling film evaporation concentration, the heat of steam is fully utilized, and the energy consumption is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of evaporation and relates to a cyclodextrin evaporation device system and a preparation method thereof. Background Art

[0002] Cyclodextrin (CD) is a bad oligosaccharide composed of D-pyranose glucose units connected by α-1,4-glycosidic bonds. The most common cyclodextrins are α-cyclodextrin, β-cyclodextrin and γ-bad dextrin, which are composed of 6, 7 and 8 glucose units respectively. Cyclodextrin is the product of cyclodextrin glucosyltransferase acting on starch. The production of cyclodextrin mainly includes the screening of strains and the preparation of CGTase, enzyme conversion, filtration, concentration, crystallization and drying. Among all the process stages, the concentration section has the highest energy consumption, and the electricity consumption and steam consumption of this section are relatively large. The concentration method of cyclodextrin is mostly evaporation concentration, which has the advantages of good heat transfer effect, fast concentration rate and high yield, and can also retain the beneficial substances in the liquid to the greatest extent.

[0003] Evaporation is divided into three types: pressurized evaporation, normal pressure evaporation and reduced pressure evaporation. Industrial evaporation operations are often carried out under reduced pressure, also known as vacuum evaporation. Its advantages are that the temperature difference between the heating steam and the liquid is increased, low-temperature evaporation is achieved, and the thermal denaturation of the liquid during the evaporation process can be reduced. The concentration effect is significant and the emissions and pollution to the atmosphere are reduced. However, vacuum evaporation also has disadvantages, because as the vacuum degree increases, the latent heat of evaporation also increases, which intensifies the energy consumption of evaporation.

[0004] Therefore, how to achieve efficient evaporation and concentration while reducing the energy consumption of the evaporator has become an urgent problem to be solved. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a cyclodextrin evaporation device system and a preparation method thereof. Under the premise of fully considering the properties of the material, a hot pressure injection device is adopted, combined with a multi-effect falling film evaporation of cyclodextrin, and the heat of steam is fully utilized to achieve the purpose of energy saving and consumption reduction.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a cyclodextrin evaporation device system, the cyclodextrin evaporation device system comprising a multi-effect evaporation unit, a preheating unit, a material source, a steam source and a hot pressure injection device; the material source is connected to the preheating unit, the preheating unit is connected to the feed end of the multi-effect evaporation unit through a feed main pipe, and the preheating unit is also connected to the multi-effect evaporation unit through at least one heat exchange pipe; the two ends of the hot pressure injection device are respectively connected to the steam source and the multi-effect evaporation unit, and the steam source is used to provide primary steam to the hot pressure injection device; the multi-effect evaporation unit comprises at least two-effect falling film evaporation devices connected in sequence along the flow direction of the primary steam; at least one of the falling film evaporation devices is connected to the hot pressure injection device through a waste heat return pipe, which is used to draw the secondary steam generated by the falling film evaporation device to the hot pressure injection device.

[0008] The present invention utilizes a multi-effect falling film evaporation device to greatly reduce the energy consumption of cyclodextrin concentration; through the design of a hot pressure injection device, the waste heat of secondary steam is recovered; the heat of the discharge material and the heat of the secondary steam are used to preheat the material, the waste heat is fully utilized, and the circulating cooling water consumption is reduced; and the material residence time is short, thereby ensuring the color and quality of the product.

[0009] It should be noted that the at least two-effect falling film evaporation device in the present invention refers to two or more falling film evaporation devices connected in sequence along the flow direction of the primary steam.

[0010] As a preferred technical solution of the present invention, a feed port and a discharge port are respectively provided at the top and the bottom of the falling film evaporation device; along the flow direction of the primary steam, the feed port of the falling film evaporation device located at the rearmost end of the multi-effect evaporation unit is connected to the preheating unit, and the feed ports of the remaining falling film evaporation devices are connected to the discharge ports of the adjacent falling film evaporation devices through feed pipes.

[0011] The falling film evaporation device is also provided with a steam inlet and a steam outlet; along the flow direction of the primary steam, the steam inlet of the falling film evaporation device located at the front end of the multi-effect evaporation unit is connected to the hot pressure injection device, and the steam outlets of the remaining falling film evaporation devices are connected to the steam inlets of the adjacent falling film evaporation devices through steam pipes.

[0012] That is, when the number of falling film evaporation devices in the present invention is recorded as n, n≥2, the falling film evaporation device located at the front end of the multi-effect evaporation unit refers to the falling film evaporation device of the first effect, and the falling film evaporation device located at the rear end of the multi-effect evaporation unit refers to the falling film evaporation device of the nth effect. The cyclodextrin material of the material source first enters the preheating unit for preheating, and then enters the falling film evaporator of the nth effect for evaporation and concentration, and the output enters the remaining falling film evaporators in the order of the n-1th effect, the n-2nd effect,..., and the first effect, and is discharged after evaporation and concentration are completed; the primary steam provided by the steam source first enters the hot pressure injection device, and then is injected into the falling film evaporator of the first effect to evaporate the cyclodextrin material, and the secondary steam generated by it enters the remaining falling film evaporator in the order of the second effect, the third effect,..., and the nth effect to evaporate the cyclodextrin material; in the present invention, the flow directions of the material and the steam are different, so that the heat can be fully utilized, the problem of secondary steam entraining the material liquid can be improved, the beneficial elements in the cyclodextrin material can be protected to the maximum extent, the properties of the cyclodextrin material can be met, and the energy consumption is greatly reduced.

[0013] Preferably, one end of the waste heat return pipe is connected to the hot pressure injection device, and the other end is connected to at least one of the steam pipes.

[0014] As a preferred technical solution of the present invention, the multiple-effect evaporation unit further comprises a condensing device, and the condensing device is connected to the steam outlet of the falling film evaporation device located at the rear end of the multiple-effect evaporation unit.

[0015] The condensing device described in the present invention is used to condense the final output material in the multiple-effect evaporation unit.

[0016] As a preferred technical solution of the present invention, the preheating unit includes at least one heat exchange device, and both ends of the heat exchange device are respectively connected to the material source and the feed inlet of the falling film evaporator located at the rear end of the multiple-effect evaporation unit.

[0017] Preferably, the preheating unit comprises at least two heat exchange devices connected in sequence along the material flow direction.

[0018] That is, when the number of falling film evaporation devices in the present invention is n, n≥2, the first heat exchange device is connected to the material source, and the last heat exchange device is connected to the feed port of the nth effect falling film evaporation device through the feed main pipe.

[0019] Preferably, one end of the heat exchange pipe is connected to the heat exchange device, and the other end is connected to the steam pipe.

[0020] The heat exchange device in the present invention utilizes the discharge heat of the falling film evaporator and the heat of the secondary steam generated by the falling film evaporator to preheat the cyclodextrin feed, thereby fully utilizing the waste heat and greatly reducing energy consumption.

[0021] The hot pressure injection device in the present invention serves as a heat source for the falling film evaporation device. Its main function is to use primary steam to extract secondary steam, increase the temperature and pressure of the secondary steam through mixed thermal compression, and serve as a partial heating heat source for the falling film evaporation device, thereby saving energy.

[0022] In a second aspect, the present invention provides a method for preparing the cyclodextrin evaporation device system according to the first aspect, the preparation method comprising:

[0023] (1) Obtaining physical parameters of cyclodextrin materials and analyzing physical properties;

[0024] (2) Determine the number of effects of the falling film evaporator according to the physical properties of the cyclodextrin material, design the heat exchange area and evaporation capacity of each effect of the falling film evaporator, and determine the temperature, pressure and discharge concentration of each effect of the falling film evaporator according to heat balance;

[0025] (3) analyzing the amount of secondary steam drawn by each falling film evaporator, combining the pressure and temperature of the primary steam in the falling film evaporator at the front end of the multi-effect evaporator, determining the ejection coefficient of the hot pressure ejector, and then determining the heating method in the preheating unit;

[0026] (4) Debug operation and select the optimal suction method for the hot pressure injection device.

[0027] Under the premise of fully considering the properties of cyclodextrin materials, the present invention provides directional guidance for determining concentration parameters, selects the best injection method, extracts the most reasonable secondary steam of the effect body, realizes the maximum utilization of heat, can significantly reduce energy consumption, and improve product quality.

[0028] As a preferred technical solution of the present invention, in step (1), the physical parameters include any one or a combination of at least two of the saturated solubility of the cyclodextrin material at different temperatures, the boiling point rise of the cyclodextrin material at different concentrations, the viscosity of the cyclodextrin material at different concentrations, and the viscosity of the cyclodextrin material at different temperatures.

[0029] As a preferred technical solution of the present invention, in step (2), the temperature of the discharge material of each effect falling film evaporator is ≥80°C.

[0030] As a preferred technical solution of the present invention, in step (3), the induced coefficient is ≥ 1.0.

[0031] As a preferred technical solution of the present invention, in step (3), determining the heating method in the preheating unit specifically includes: determining the preheating area of ​​the preheating unit, and selecting a falling film evaporator of at least one effect in the multi-effect evaporation unit, connecting it to the preheating unit through a heat exchange pipe, so as to transport the secondary steam generated by the falling film evaporator to the preheating unit.

[0032] As a preferred technical solution of the present invention, in step (4), the selection of the suction method of the hot pressure injection device specifically includes: selecting a falling film evaporation device of at least one effect in the multi-effect evaporation unit, connecting it to the hot pressure injection device through a waste heat return pipe, so as to transport the secondary steam generated by the falling film evaporation device to the hot pressure injection device.

[0033] The system refers to an equipment system, a device system or a production device.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention provides a cyclodextrin evaporation device system and a preparation method thereof. On the premise of fully considering the properties of cyclodextrin materials, a hot pressure injection device is adopted, combined with multi-effect falling film evaporation, secondary steam waste heat is recovered, and the heat of steam is fully utilized through heat exchange between inlet and outlet materials to achieve the purpose of energy saving and consumption reduction, reduce circulating cooling water consumption, and the water vapor consumption per ton of evaporation is less than 0.29t, which has high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of the preparation of a cyclodextrin evaporation device system provided in Example 1 of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the cyclodextrin evaporation device system provided in Example 1 of the present invention.

[0038] Among them, 1-first effect falling film evaporation device; 2-second effect falling film evaporation device; 3-third effect falling film evaporation device; 4-fourth effect falling film evaporation device; 5-first heat exchange device; 6-second heat exchange device; 7-third heat exchange device; 8-hot pressure injection device; 9-material source; 10-steam source; 11-condensing device; 101-feed main pipe; 102-feed pipe; 103-first steam pipe; 104-second steam pipe; 105-third steam pipe; 106-first heat exchange pipe; 107-second heat exchange pipe; 108-third heat exchange pipe; 109-waste heat return pipe. DETAILED DESCRIPTION

[0039] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0040] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0041] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0042] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0043] In a specific embodiment, the present invention provides a cyclodextrin evaporation device system, including a multi-effect evaporation unit, a preheating unit, a material source, a steam source and a hot pressure injection device. The material source is connected to the preheating unit, and the preheating unit is connected to the feed end of the multi-effect evaporation unit through a feed main pipe, which is used to preheat the cyclodextrin material. The preheating unit is also connected to the multi-effect evaporation unit through at least one heat exchange pipeline to achieve heat exchange between inlet and outlet materials and make full use of heat. The two ends of the hot pressure injection device are respectively connected to the steam source and the multi-effect evaporation unit, and the steam source is used to provide primary steam to the hot pressure injection device; the multi-effect evaporation unit includes at least two falling film evaporation devices connected in sequence along the flow direction of the primary steam; at least one falling film evaporation device is connected to the hot pressure injection device through a waste heat return pipe, which is used to draw the secondary steam generated by the falling film evaporation device to the hot pressure injection device. The hot pressure injection device serves as the heat source of the falling film evaporator. The primary steam provided by the steam source is injected into the multi-effect evaporation unit. At the same time, the primary steam is used to absorb the secondary steam generated by the falling film evaporator. After mixed heat compression, it serves as a partial heating heat source for the falling film evaporator.

[0044] The hot pressure injection device described in the present invention must include a nozzle, a mixing chamber, a diffusion tube, an insulation layer and a shell for realizing a complete process. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection. The present invention does not make specific limitations on this. Similarly, any other style of ejector known to those skilled in the art that can realize the use of primary steam to extract secondary steam and perform mixed hot compression can also be used.

[0045] In some embodiments, the top and bottom of the falling film evaporation device are respectively provided with a feed port and a discharge port; along the flow direction of the primary steam, the feed port of the falling film evaporation device at the rear end of the multi-effect evaporation unit is connected to the preheating unit, and the feed ports of the remaining falling film evaporation devices are connected to the discharge ports of the adjacent falling film evaporation devices through a feed pipe. When the number of falling film evaporation devices in the present invention is n, n≥2, the cyclodextrin material of the material source first enters the preheating unit for preheating, and then enters the falling film evaporation device of the nth effect for evaporation and concentration, and its discharge enters the falling film evaporation device of the n-1th effect for further evaporation and concentration, and the discharge of the falling film evaporation device of the n-1th effect enters the falling film evaporation device of the n-2th effect for evaporation and concentration, and so on, the cyclodextrin material finally enters the falling film evaporation device of the first effect to be concentrated and then discharged.

[0046] The falling film evaporation device is also provided with a steam inlet and a steam outlet; along the flow direction of the primary steam, the steam inlet of the falling film evaporation device at the front end of the multi-effect evaporation unit is connected to the hot pressure injection device, and the steam outlets of the remaining falling film evaporation devices are connected to the steam inlets of the adjacent falling film evaporation devices through steam pipes. When the number of falling film evaporation devices in the present invention is n, n≥2, the primary steam provided by the steam source first enters the hot pressure injection device, and then is injected into the falling film evaporation device of the first effect to evaporate the cyclodextrin material, and the secondary steam generated by it enters the falling film evaporation device of the second effect to evaporate the cyclodextrin material, and so on, the secondary steam generated by the falling film evaporation device of the n-1th effect finally enters the falling film evaporation device of the nth effect to evaporate the cyclodextrin material.

[0047] The falling film evaporation device used in the present invention has the advantages of low heating temperature, fast evaporation rate, short residence time of materials in the equipment, and energy saving, and can maximize the protection of beneficial elements of cyclodextrin materials during heating and evaporation. The falling film evaporation device in the present invention adopts the falling film evaporation equipment commonly used in the art, which must include a liquid distributor, a falling film tube, a heating tube, necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main invention of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0048] During the application process, the liquid distributor distributes the cyclodextrin feed evenly to each falling film tube, and ensures that the material in each falling film tube flows downward along the tube wall in the form of a liquid film. The material flows in the falling film tube under the combined action of gravity and secondary steam flow. Since it is not the secondary steam that overcomes the gravity of the material itself to push it upward to form a film, but the material flows downward while evaporating until it reaches the bottom of the falling film tube, the material and the secondary steam are basically separated, which alleviates the phenomenon of secondary steam entraining materials, making the filming and evaporation process of the material in the heating tube more stable and orderly.

[0049] In some embodiments, the multiple-effect evaporation unit further comprises a condensing device, which is connected to the steam outlet of the falling film evaporation device at the rear end of the multiple-effect evaporation unit, so that the steam discharged from the falling film evaporation device of the nth effect enters the condensing device for condensation and recovery.

[0050] The present invention does not specifically limit the structure of the condensing device, and any type of condensing equipment commonly used in the art may be used, including but not limited to a spray condenser, a filling condenser, a water sprinkling plate condenser or a sieve plate condenser, etc.

[0051] In some embodiments, the preheating unit includes at least one heat exchange device, and two ends of the heat exchange device are respectively connected to the material source and the feed inlet of the falling film evaporator located at the rear end of the multiple-effect evaporation unit.

[0052] Furthermore, the preheating unit includes at least two heat exchange devices connected in sequence along the material flow direction. In the present invention, two adjacent heat exchange devices are connected in sequence, the first heat exchange device at the head end is connected to the material source, and the last heat exchange device at the tail end is connected to the feed inlet of the n-th effect falling film evaporation device. Specifically, one end of the heat exchange pipe is connected to the heat exchange device, and the other end is connected to the steam pipe.

[0053] During the application of the present invention, the number of heat exchange devices is adjusted according to the heat exchange area of ​​the cyclodextrin material. The cyclodextrin material provided by the material source flows through the first heat exchange device, the second heat exchange device, ..., and the mth heat exchange device in sequence. After the preheating of the material is completed, it enters the nth effect falling film evaporation device for single-effect evaporation, and then flows through the n-1th effect falling film evaporation device, ..., and the first effect falling film evaporation device in sequence to complete the multi-effect evaporation process. The heat source of the heat exchange device comes from the heat of the discharge of the falling film evaporation device and the heat of the secondary steam. Compared with the traditional method of using raw steam to heat the cyclodextrin material, the present invention makes full use of waste heat and greatly reduces energy consumption.

[0054] Exemplarily, according to the heat exchange area of ​​the cyclodextrin material, the present invention sets m heat exchange devices in the preheating unit, wherein m=n-1, and the first heat exchange device is connected to the steam pipe of the falling film evaporator connecting the n-th effect and the n-1-th effect through a heat exchange pipe, and the second heat exchange device is connected to the steam pipe of the falling film evaporator connecting the n-1-th effect and the n-2-th effect through a heat exchange pipe, and so on, the m-th heat exchange device is connected to the steam pipe of the falling film evaporator connecting the second effect and the first effect through a heat exchange pipe to realize heat exchange of the inlet and outlet materials.

[0055] In the present invention, the secondary steam of at least one falling film evaporation device is drawn into the hot pressure injection device by the waste heat return pipe, and after thermal compression, the temperature and pressure of the secondary steam are increased, and then enters the first effect falling film evaporation device as a heat source. In the application process, those skilled in the art can connect the end of the waste heat return pipe away from the hot pressure injection device to any steam pipeline that meets the heat requirements according to the actual heat demand, and only one falling film evaporation device provides secondary steam; or the end of the waste heat return pipe away from the hot pressure injection device can be connected to two or more steam pipelines, and multiple falling film evaporation devices can jointly provide secondary steam.

[0056] Preferably, in order to reduce the complexity of pipeline connection, the end of the waste heat return pipe away from the hot pressure injection device can be directly connected to the heat exchange pipe, and the secondary steam entering the heat exchange pipe from the steam pipe is divided into two paths, one path enters the heat exchange device to preheat the feed, and the other path enters the hot pressure injection device to perform thermal compression under the action of the primary steam.

[0057] In another specific embodiment, the present invention provides a method for preparing a cyclodextrin evaporation device system according to a specific embodiment, the preparation method comprising:

[0058] Step I: Obtain the physical parameters of the cyclodextrin material, analyze the physical properties, and use the basic information of the cyclodextrin material as a basis to obtain the optimal concentration parameters, thereby reducing the energy consumption in the concentration process.

[0059] The physical parameters include any one or a combination of at least two of the saturated solubility of the cyclodextrin material at different temperatures, the boiling point rise of the cyclodextrin material at different concentrations, the viscosity of the cyclodextrin material at different concentrations, and the viscosity of the cyclodextrin material at different temperatures.

[0060] Specifically, the different concentration ranges can be a cyclodextrin with a mass concentration of 0% to 78%, for example, 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75% or 78%, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0061] Specifically, the temperature range may be 30-90°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0062] In order to more fully understand the properties of cyclodextrin materials, the present invention can prepare cyclodextrin materials of different concentrations (mass concentration is 10% to 78%) and measure the viscosity of the cyclodextrin materials at different concentrations and different temperatures (30 to 90° C.) using a viscosity meter.

[0063] The present invention performs solubility and boiling point rise measurement and fitting on a cyclodextrin material with complex ingredients to provide directional guidance for the design of concentration parameters. Specifically, the saturated solubility corresponding to the cyclodextrin material at different temperatures is first measured, and then the boiling point rise of the cyclodextrin material at different concentrations is measured, and the obtained data curve is fitted to achieve maximum utilization of heat.

[0064] Exemplarily, the boiling point rise can be obtained by preparing cyclodextrin solutions of different concentrations (mass concentration is 0% to 78%), heating them to boil on an induction cooker, and measuring the temperature at different concentrations using a digital thermometer. The boiling point rise can also be measured by other methods well known to those skilled in the art, and the present invention does not specifically limit this.

[0065] Step II: According to the physical properties of the cyclodextrin material, determine the number of effects of the falling film evaporator, design the heat exchange area and evaporation capacity of each effect of the falling film evaporator, and determine the temperature, pressure and discharge concentration of each effect of the falling film evaporator based on heat balance. Theoretically, the more the number of effects of multi-effect evaporation, the more steam is saved, but the corresponding power consumption and equipment cost will also increase accordingly. Therefore, the present invention selects the optimal number of effects after comprehensive analysis.

[0066] Exemplarily, the calculation formula for the heat exchange area of ​​each effect falling film evaporator is as follows:

[0067]

[0068] Among them, Q i is the heat of the falling film evaporator, in kJ·h -1 (i=1,2,····n, i is an integer); k is the heat transfer coefficient, unit is kJ·(m 2 ·h·℃) -1 ; F i is the heat exchange area, in m 2 (i=1,2,····n, i is an integer); Δt is the heat transfer temperature difference of a single falling film evaporation device, in ℃.

[0069] The calculation formula for the evaporation intensity of each effect falling film evaporator is as follows:

[0070]

[0071] Among them, U i is the evaporation capacity of the falling film evaporator, in kg / (m 2 ·h)(i=1,2,····n, i is an integer); F i is the heat exchange area, in m 2 (i=1,2,····n, i is an integer); W is (total amount of water evaporation, kg / h).

[0072] The calculation formula for the discharge concentration of each effect falling film evaporator is as follows:

[0073] S i-1 B i-1 =(S i-1 -W i )×B i

[0074] Among them, S i-1 is the feed rate, in kg / h (i=1, 2, ····n, i is an integer); B i-1 is the feed concentration; B i is the discharge concentration, the unit is g / 100g (i=1, 2, ····n, i is an integer); W i is the amount of evaporated water, the unit is kg / h (i=1, 2,...n, i is an integer).

[0075] The heat balance formula for each effect falling film evaporator is as follows:

[0076]

[0077] Among them, D i is the steam consumption, in kg / h (i=1, 2, ····n, i is an integer); R i is the latent heat of heating steam, the unit is kJ / kg (i=1,2,····n, i is an integer); W i is the total amount of water evaporation, in kg / h (i=1, 2, ····n, i is an integer); r i is the heat of vaporization of secondary steam, in kJ / kg (i=1,2,····n, i is an integer); S is the feed rate, in kg / h; c is the specific heat capacity of the material, in kJ / (kg·℃); t i is the boiling point of the feed liquid, in °C (i=1, 2,...n, i is an integer); Q i is the heat of steam preheating the material, in kJ / h (i=1, 2,...n, i is an integer); q i is the heat loss, and its unit is kJ / kg (i=1,2,····n, i is an integer).

[0078] In addition, the present invention needs to ensure that the temperature of the discharge material of each effect falling film evaporator is ≥80°C.

[0079] Step III: Analyze the amount of secondary steam drawn by each effect falling film evaporator, combine the pressure and temperature of the primary steam in the falling film evaporator at the front end of the multi-effect evaporation unit, determine the ejection coefficient of the hot pressure injection device, and then determine the heating method in the preheating unit.

[0080] The ejection coefficient μ in the present invention refers to the ratio of the amount of inhaled steam to the amount of working steam, indicating how many kilograms of secondary steam can be extracted for recompression using one kilogram of high-pressure steam. The larger the μ value, the more energy-saving it is. The ejection coefficient of the hot pressure ejector is directly related to the amount of steam consumed and the use effect of the equipment. The ejection coefficient in the present invention is preferably ≥1.0. If the ejection coefficient is too small, the steam consumption increases, which may cause thermal imbalance in the evaporation system; if the ejection coefficient is too large, the steam consumption decreases, which may lead to insufficient production capacity.

[0081] The present invention can determine the injection coefficient by the compression ratio and expansion ratio of the hot pressure injection device in combination with Table 1 (injection coefficient corresponding table), wherein the calculation formula of the compression ratio and the expansion ratio is as follows:

[0082]

[0083] Table 1

[0084]

[0085]

[0086] Specifically, the determination of the heating method in the preheating unit specifically includes: determining the preheating area of ​​the preheating unit, and selecting a falling film evaporator of at least one effect in the multi-effect evaporation unit, and connecting it to the heat exchange device through a heat exchange pipe, so as to transport the secondary steam generated by the falling film evaporator to the heat exchange device. That is, according to the actual preheating area, the present invention comprehensively analyzes the number of falling film evaporators for secondary steam recycling, and connects a corresponding number of falling film evaporators to the heat exchange device through heat exchange pipes to meet the heat demand required for preheating. Since the process of feeding cyclodextrin materials requires higher heat, the traditional process is to use primary steam for direct heating, which greatly increases energy consumption. After determining the preheating area, the present invention comprehensively recovers the waste heat of the secondary steam generated by the falling film evaporator and the waste heat of the discharge, thereby achieving the purpose of reducing energy consumption.

[0087] The present invention is based on the principles of conservation of mass and heat, and according to heat balance, determines the optimal evaporation parameters through repeated regression iterations.

[0088] Step IV: Debug operation, measure and correct, and select the optimal suction method for the hot pressure injection device.

[0089] Under the premise of fully considering the properties of cyclodextrin materials, the present invention provides directional guidance for determining the concentration parameters, selects a falling film evaporator with at least one effect in a multi-effect evaporation unit, and connects it to a hot pressure injection device through a waste heat return pipe, so as to transport the secondary steam generated by the falling film evaporator to the hot pressure injection device.

[0090] In the present invention, which effect of the falling film evaporator to draw the secondary steam from is crucial to the entire evaporation unit, and directly determines the lower limit of the overall energy consumption of the equipment. Through multiple debugging operations, the most energy-saving injection method is determined to meet the properties of the cyclodextrin material, which can minimize the process cost.

[0091] Example 1

[0092] This embodiment provides a method for preparing a cyclodextrin evaporation device system. Figure 1 As shown, the specific steps include:

[0093] (1) Based on the existing cyclodextrin materials, the properties of the cyclodextrin materials, such as the viscosity of the materials, were studied. Cyclodextrin materials of different concentrations (mass concentration was 10% to 78%) were prepared and the viscosity of the materials at different concentrations and different temperatures (30 to 90° C.) was measured using a viscosity meter.

[0094] (2) Based on the properties of cyclodextrin materials, the saturated solubility of cyclodextrin materials at different temperatures (30-90°C) is first determined, and then the boiling point rise of cyclodextrin materials at different concentrations (mass concentration is 10%-78%) is determined, and the resulting data curve is fitted; wherein, by preparing cyclodextrin solutions of different concentrations (mass concentration is 0%-78%), heating them to boil on an induction cooker, and measuring the temperature at different concentrations with a digital thermometer, the corresponding boiling point rise can be obtained.

[0095] (3) Determine the number of effects of the falling film evaporator as four, design the heat exchange area and evaporation capacity of each effect of the falling film evaporator, and determine the temperature, pressure and discharge concentration of each effect of the falling film evaporator based on heat balance;

[0096] The calculation formula for the heat exchange area of ​​each effect falling film evaporator is as follows:

[0097]

[0098] The calculation formula for the evaporation intensity of each effect falling film evaporator is as follows:

[0099]

[0100] The discharge concentration of the first effect falling film evaporator is:

[0101] S 0 B 0 =(S 0 -W 1 )×B 1 ;

[0102] The discharge concentration of the second effect falling film evaporator is:

[0103] S1 B 1 =(S 1 -W 2 )×B 2 ;

[0104] The discharge concentration of the third effect falling film evaporator is:

[0105] S 2 B 2 =(S 2 -W 3 )×B 3 ;

[0106] The discharge concentration of the fourth effect falling film evaporator is:

[0107] S 3 B 3 =(S 3 -W 4 )×B 4 .

[0108] The heat balance formula of the first effect falling film evaporator is as follows:

[0109] D 1 R 1 =W 1 r 1 +Sc×(t 1 -t 0 )+Q 1 -q 1 ;

[0110] The heat balance formula of the second effect falling film evaporator is as follows:

[0111] D 2 R 2 =W 2 r 2 +(Sc-c p ×W 1 )×(t 2 -t 1 )+Q 2 -q 2 ;

[0112] The heat balance formula of the third effect falling film evaporator is as follows:

[0113] D 3 R 3 =W 3 r 3 +(Sc-c p ×W 1 -c p ×W 2 )×(t 3 -t2 )+Q 3 -q 3 ;

[0114] The heat balance formula of the fourth effect falling film evaporator is as follows:

[0115] D 4 R 4 =W 4 r 4 +(Sc-c p ×W 1 -c p ×W 2 -c p ×W 3 )×(t 4 -t 3 )+Q 4 -q 4 .

[0116] (4) The amount of secondary steam drawn into each falling film evaporator was analyzed, and combined with the pressure and temperature of the primary steam in the first falling film evaporator, the compression ratio (δ) was 1.6, the expansion ratio (β) was 100, and the ejection coefficient of the hot pressure ejector was determined to be 1.83.

[0117] (5) Determine the preheating area of ​​the preheating unit, and select a three-effect falling film evaporator in the multi-effect evaporation unit, and connect it to the heat exchange device through a heat exchange pipe to transport the secondary steam generated by the falling film evaporator to the heat exchange device.

[0118] (6) Based on the principles of conservation of mass and heat, and according to heat balance, the optimal evaporation parameters are determined through repeated regression iterations.

[0119] (7) Under the premise of fully considering the properties of cyclodextrin materials, the falling film evaporator of the first effect in the multi-effect evaporation unit was selected for debugging and operation, and the falling film evaporator was connected to the hot pressure injection device through a waste heat return pipe to transport the secondary steam generated by the falling film evaporator to the hot pressure injection device.

[0120] The specific structure of the cyclodextrin evaporation device system prepared in this embodiment is as follows: Figure 2As shown, it specifically includes a multi-effect evaporation unit, a preheating unit, a material source 9, a steam source 10 and a hot pressure injection device 8. The multi-effect evaporation unit includes four-effect falling film evaporation devices connected in sequence, which are respectively recorded as a first-effect falling film evaporation device 1, a second-effect falling film evaporation device 2, a third-effect falling film evaporation device 3 and a fourth-effect falling film evaporation device 4. A feed inlet and a discharge port are respectively arranged at the top and the bottom of each effect of the falling film evaporation device, and a steam inlet and a steam outlet are arranged on both sides. The preheating unit includes a first heat exchange device 5, a second heat exchange device 6 and a third heat exchange device 7 connected in sequence. The first heat exchange device 5 is connected to the material source 9, and the third heat exchange device 7 is connected to the feed inlet of the fourth-effect falling film evaporation device 4 through a feed main pipe 101. The discharge port of the fourth effect falling film evaporation device 4 is connected to the feed port of the third effect falling film evaporation device 3 through the feed pipe 102, and the discharge port of the third effect falling film evaporation device 3 is connected to the feed port of the second effect falling film evaporation device 2 through the feed pipe 102; the discharge port of the second effect falling film evaporation device 2 is connected to the feed port of the first effect falling film evaporation device 1 through the feed pipe 102, and the discharge port of the first effect falling film evaporation device 1 is connected to the outside world for discharging the final product of cyclodextrin concentration. One end of the hot pressure injection device 8 is connected to the steam source 10, and the other end is connected to the steam inlet of the first effect falling film evaporation device 1. The steam outlet of the first effect falling film evaporation device 1 is connected to the steam inlet of the second effect falling film evaporation device 2 through the first steam pipe 103, the steam outlet of the second effect falling film evaporation device 2 is connected to the steam inlet of the third effect falling film evaporation device 3 through the second steam pipe 104, the steam outlet of the third effect falling film evaporation device 3 is connected to the steam inlet of the fourth effect falling film evaporation device 4 through the third steam pipe 105, and the steam outlet of the fourth effect falling film evaporation device 4 is connected to the condensing device 11. The first steam pipe 103 is also connected to the third heat exchange device 7 through the first heat exchange pipe 106, the second steam pipe 104 is also connected to the second heat exchange device 6 through the second heat exchange pipe 107, and the third steam pipe 105 is also connected to the first heat exchange device 5 through the third heat exchange pipe 108. The first heat exchange pipe 106 is also connected to the hot pressure injection device 8 through the waste heat return pipe 109, which is used to draw the secondary steam generated by the first effect falling film evaporation device 1 to the hot pressure injection device 8.

[0121] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A cyclodextrin evaporation device system, characterized in that: The cyclodextrin evaporation device system comprises a multi-effect evaporation unit, a preheating unit, a material source, a steam source and a hot pressure injection device; The material source is connected to the preheating unit, the preheating unit is connected to the feed end of the multi-effect evaporation unit through a feed main pipe, and the preheating unit is also connected to the multi-effect evaporation unit through at least one heat exchange pipe; The two ends of the hot pressure injection device are respectively connected to the steam source and the multi-effect evaporation unit, and the steam source is used to provide primary steam to the hot pressure injection device; The multi-effect evaporation unit comprises at least two falling film evaporation devices connected in sequence along the flow direction of the primary steam; at least one of the falling film evaporation devices is connected to the hot pressure injection device through a waste heat return pipe, which is used to draw the secondary steam generated by the falling film evaporation device to the hot pressure injection device.

2. The cyclodextrin evaporation device system according to claim 1, characterized in that: The top and bottom of the falling film evaporation device are respectively provided with a feed inlet and a discharge outlet; Along the flow direction of the primary steam, the feed inlet of the falling film evaporator at the rear end of the multiple-effect evaporator unit is connected to the preheating unit, and the feed inlets of the remaining falling film evaporators are connected to the discharge outlets of the adjacent falling film evaporators through feed pipes; The falling film evaporation device is also provided with a steam inlet and a steam outlet; Along the flow direction of the primary steam, the steam inlet of the falling film evaporation device located at the front end of the multiple-effect evaporation unit is connected to the hot pressure injection device, and the steam outlets of the remaining falling film evaporation devices are connected to the steam inlets of the adjacent falling film evaporation devices through steam pipelines; Preferably, one end of the waste heat return pipe is connected to the hot pressure injection device, and the other end is connected to at least one of the steam pipes.

3. The cyclodextrin evaporation device system according to claim 2, characterized in that: The multiple-effect evaporation unit further comprises a condensing device, and the condensing device is connected to the steam outlet of the falling film evaporation device located at the rearmost end of the multiple-effect evaporation unit.

4. The cyclodextrin evaporation device system according to claim 2 or 3, characterized in that: The preheating unit comprises at least one heat exchange device, and two ends of the heat exchange device are respectively connected to the material source and the feed inlet of the falling film evaporation device located at the rear end of the multiple-effect evaporation unit; Preferably, the preheating unit comprises at least two heat exchange devices connected in sequence along the material flow direction; Preferably, one end of the heat exchange pipe is connected to the heat exchange device, and the other end is connected to the steam pipe.

5. A method for preparing the cyclodextrin evaporation device system according to any one of claims 1 to 4, characterized in that: The preparation method comprises: (1) Obtaining physical parameters of cyclodextrin materials and analyzing physical properties; (2) Determine the number of effects of the falling film evaporator according to the physical properties of the cyclodextrin material, design the heat exchange area and evaporation capacity of each effect of the falling film evaporator, and determine the temperature, pressure and discharge concentration of each effect of the falling film evaporator according to heat balance; (3) analyzing the amount of secondary steam drawn by each falling film evaporator, combining the pressure and temperature of the primary steam in the falling film evaporator at the front end of the multi-effect evaporator, determining the ejection coefficient of the hot pressure ejector, and then determining the heating method in the preheating unit; (4) Debug operation and select the optimal suction method for the hot pressure injection device.

6. The preparation method according to claim 5, characterized in that: In step (1), the physical parameters include any one or a combination of at least two of the saturated solubility of the cyclodextrin material at different temperatures, the boiling point rise of the cyclodextrin material at different concentrations, the viscosity of the cyclodextrin material at different concentrations, and the viscosity of the cyclodextrin material at different temperatures.

7. The preparation method according to claim 5, characterized in that: In step (2), the temperature of the discharge material of each falling film evaporation device is ≥80°C.

8. The preparation method according to claim 5, characterized in that: In step (3), the induced coefficient is ≥ 1.

0.

9. The preparation method according to claim 5, characterized in that: In step (3), determining the heating method in the preheating unit specifically includes: Determine the preheating area of ​​the preheating unit, and select a falling film evaporator of at least one effect in the multi-effect evaporation unit, and connect it to the preheating unit through a heat exchange pipe to transport the secondary steam generated by the falling film evaporator to the preheating unit.

10. The preparation method according to claim 5, characterized in that: In step (4), the selection of the suction method of the hot pressure injection device specifically includes: A falling film evaporator of at least one effect in the multi-effect evaporation unit is selected and connected to the hot pressure injection device through a waste heat return pipe to transport the secondary steam generated by the falling film evaporator to the hot pressure injection device.

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