Citric acid extraction and purification system

Abstract

The citric acid extraction and purification system comprises an acidolysis tank, a filtering device, an ion exchanger, a plate type evaporator, a crystallizing tank, a centrifugal machine and a fluidized bed which are sequentially connected, a raw material inlet and a strong acid inlet are formed in the upper end of the acidolysis tank, the raw material inlet is connected with a citric acid calcium salt supply pipeline, and the strong acid inlet is connected with a sulfuric acid supply pipeline. According to the utility model, citric acid is obtained from citric acid calcium salt by utilizing the principle of preparing weak acid from strong acid, and impurities in the citric acid calcium salt are cleaned by utilizing a filtering and ion exchange adsorption method, so that the purity and the comprehensive yield of a product can be greatly improved; meanwhile, a triple-effect evaporation system is combined, the citric acid solution is efficiently concentrated through multi-stage evaporation, and salting-out and scaling blockage in the concentration process are effectively avoided; citric acid crystals are efficiently collected through the crystallizing tank, the centrifugal machine and the fluidized bed, and secondary pollution is avoided; the system is comprehensive in function and simple to operate, and has a good market application prospect.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of organic acid production, especially relates to a citric acid extraction and purification system. BACKGROUND

[0002] Citric acid (Citric Acid, CA for short) is an important organic acid, also known as citric acid, colorless crystal, often contains a molecule of crystal water, odorless, has very strong sour taste, easily soluble in water. Its calcium salt is more soluble in cold water than in hot water, which is often used to identify and separate citric acid. The proper temperature can be controlled to obtain anhydrous citric acid. It has many uses in industry, food industry, cosmetics industry, etc.

[0003] Calcium salt method is the mainstream extraction method of citric acid at present, the principle of calcium salt method is to use the small solubility of calcium citrate in hot water, through the reaction of citric acid and calcium carbonate (or calcium oxide, calcium hydroxide) to form calcium citrate, so as to realize the separation of citric acid and other components of fermentation broth, and then use sulfuric acid to decompose calcium citrate to obtain citric acid again, but the by-product content of calcium salt method for extracting citric acid is high, and the purity and yield are low.

[0004] Therefore, in view of the deficiencies of the prior art, it is necessary to design a citric acid extraction and purification system to solve the above problems.

[0005] It should be noted that the above introduction to the technical background is only to facilitate the clear and complete description of the technical scheme of the utility model, and to facilitate the understanding of those skilled in the art, and the above content cannot be considered as known by those skilled in the art because the above content is described in the background of the utility model. Utility model content

[0006] In order to overcome the deficiencies in the prior art, the utility model aims at disclosing a citric acid extraction and purification system, which is used to solve the problems of high by-product content, low purity and low yield of citric acid in traditional calcium salt method for extracting citric acid.

[0007] The utility model discloses a citric acid extraction and purification system, which comprises acidolysis tank, filter device, ion exchanger, plate evaporator, crystallization tank, centrifuge and fluidized bed which are connected in sequence, wherein:

[0008] The upper end of the acidolysis tank is provided with a raw material inlet and a strong acid inlet, the raw material inlet is connected with a calcium citrate supply pipeline, the strong acid inlet is connected with a sulfuric acid supply pipeline, and the principle of preparing weak acid by using strong acid is used to decompose calcium citrate by using sulfuric acid to obtain a citric acid solution again; the lower end of the acidolysis tank is provided with a discharge port connected with a feed inlet of a filtering device through a pipeline, and the filtering device is used for removing calcium sulfate and other solid particles in the citric acid solution; a discharge port of the filtering device is connected with a feed inlet of an ion exchanger through a pipeline, and the ion exchanger is used for further removing impurity ions in the citric acid solution; a discharge port of the ion exchanger is connected with a feed inlet of a plate evaporator through a pipeline, an air inlet of the plate evaporator is connected with a steam supply pipeline, and the plate evaporator is used for rapidly concentrating the citric acid solution; the plate evaporator is connected with a feed inlet of a crystallization tank through a pipeline, and the crystallization tank is used for forming citric acid crystals; a discharge port of the crystallization tank is connected with a feed inlet of a centrifuge through a pipeline, and the centrifuge is used for removing residual solution in the citric acid crystals; and a discharge port of the centrifuge is connected with a feed inlet of a fluidized bed through a pipeline, and the fluidized bed is used for rapidly drying the citric acid crystals.

[0009] Preferably, the filtering device is one of a plate-and-frame filter and a belt filter, or a combination of both.

[0010] Preferably, the ion exchanger is composed of at least two groups of resin tanks arranged in parallel, and the resin tank is provided with a resin bed and a water distribution device, so as to increase the stripping efficiency of impurity ions in the citric acid solution.

[0011] Preferably, the plate evaporator is a three-effect plate evaporator, so as to improve the utilization rate of steam energy.

[0012] Preferably, the exhaust port of the plate evaporator is connected with the condenser and the air inlet of the plate evaporator through pipelines, respectively.

[0013] Preferably, the crystallization tank is provided with a jacket, and the jacket is in communication with a cooling water supply pipeline.

[0014] Preferably, the pipelines in the system are all provided with valves, so as to facilitate fine control of the system.

[0015] Preferably, the acidolysis tank and the crystallization tank are provided with stirring devices, so as to accelerate the reaction speed of materials in the tanks.

[0016] Thanks to the above technical scheme, the present application has the following beneficial effects compared with the prior art:

[0017] The utility model discloses a kind of citric acid extraction and purification systems, using the principle of weak acid from strong acid, citric acid is obtained from calcium citrate, impurities are cleaned using filtering device, ion exchanger utilizes the different distribution coefficients of citric acid and non-citric acid substance in the system formed by stationary phase (specific resin) and mobile phase (hot water), when two phases are relatively moved, citric acid and non-citric acid substance move with mobile phase, and repeatedly distribute in two phases multiple times, so as to separate citric acid, can greatly improve the purity and comprehensive yield of product;Citric acid solution is efficiently concentrated by multi-stage evaporation, saltation and fouling blockage in concentration process are effectively avoided simultaneously in combination with triple-effect evaporation system;Citric acid crystal is efficiently collected by crystallizing tank, centrifuge and fluidized bed, avoid secondary pollution;The system is comprehensive in function, easy to operate, with good market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0018] To more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 It is a structural schematic view of the citric acid extraction and purification system of the utility model.

[0020] In the above drawings, 1, acidolysis tank;11, raw material inlet;12, strong acid inlet;2, filtering device;3, ion exchanger;31, resin tank;4, plate evaporator;5, crystallizing tank;51, jacket;6, centrifuge;7, fluidized bed. DETAILED DESCRIPTION

[0021] The following specific embodiments illustrate the embodiments of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification.

[0022] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application and the above drawings are intended to distinguish between similar objects and not necessarily in a particular order or sequence. It should be understood that the data thus used can be interchanged, where appropriate, to describe the embodiments of the present application. In addition, the terms "comprise" and "have" and their synonyms, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a list of steps or units does not necessarily limit those steps or units to the clearly listed ones, but can include other steps or units not clearly listed or inherent to such processes, methods, products or devices.

[0023] In the present application, the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like are based on the orientations or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to necessarily having a particular orientation, or being constructed and operated in a particular orientation.

[0024] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present application can be understood according to the specific circumstances.

[0025] In addition, the terms "mount", "set", "provided with", "connected", "connected", "sleeved", "attached" should be broadly understood. For example, "connected" can be fixedly connected, detachably connected, or integrally constructed; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For example, "attached" can be completely attached or partially attached. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0026] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0027] Embodiment:

[0028] As Figure 1As shown in the utility model discloses a kind of citric acid extraction and purification system, including acidolysis jar 1, filter device 2, ion exchanger 3, plate evaporator 4, crystallizing jar 5, centrifuge 6 and fluidized bed 7 connected in sequence, the following will be described in detail to the main components of the above utility model:

[0029] As Figure 1 As shown, the upper end of acidolysis jar 1 is provided with raw material inlet 11 and strong acid inlet 12, raw material inlet 11 is connected with calcium citrate supply pipeline, strong acid inlet 12 is connected with sulfuric acid supply pipeline, the lower end of acidolysis jar 1 is provided with discharge port connected with the feed inlet of filter device 2 through pipeline, the discharge port of filter device 2 is connected with the feed inlet of ion exchanger 3 through pipeline, the discharge port of ion exchanger 3 is connected with the feed inlet of plate evaporator 4 through pipeline, the gas inlet of plate evaporator 4 is connected with steam supply pipeline, plate evaporator 4 is connected with the feed inlet of crystallizing jar 5 through pipeline, the discharge port of crystallizing jar 5 is connected with the feed inlet of centrifuge 6 through pipeline, the discharge port of centrifuge 6 is connected with the feed inlet of fluidized bed 7 through pipeline.

[0030] The use method and principle of the utility model are as follows: when used, calcium citrate enters acidolysis jar 1 through raw material inlet 11, sulfuric acid enters acidolysis jar 1 through strong acid inlet 12, using the principle of preparing weak acid with strong acid, using sulfuric acid to decompose calcium citrate to obtain citric acid solution, calcium sulfate and other solid particles, then the solution after reaction is filtered by filter device 2 to filter out calcium sulfate and other solid particles in it, the filtered citric acid solution is stripped of impurity ions by ion exchanger 3, then it is concentrated quickly by plate evaporator 4, the concentrated solution enters crystallizing jar 5 to precipitate citric acid crystals by cooling; then the precipitated citric acid crystals enter centrifuge 6 to remove residual liquid, and finally high-purity citric acid is obtained by rapid drying in fluidized bed 7.

[0031] As Figure 1 As shown, to ensure the filtering effect, filter device 2 is one of plate and frame filter and belt filter or a combination of the two.

[0032] As Figure 1 As shown, to improve the removal efficiency of impurities, ion exchanger 3 is composed of six groups of resin tanks 31 arranged in parallel, resin bed and water distribution device are arranged in resin tank 31.

[0033] As Figure 1 As shown, to improve the utilization rate of steam energy, plate evaporator 4 is a three-effect plate evaporator, which improves the energy utilization rate of high-temperature steam through multi-stage evaporation.

[0034] As Figure 1As shown, in order to improve the utilization rate of steam energy, the exhaust port of the plate evaporator 4 is connected with the condenser and the air inlet of the plate evaporator 4 through pipelines respectively, so that part of the steam can be recycled from the exhaust port of the plate evaporator 4 to the air inlet of the plate evaporator 4.

[0035] As shown in the figure, Figure 1 As shown, in order to improve the preparation efficiency of citric acid, the jacket 51 is arranged on the crystallization tank 5, which can be communicated with the cooling water supply pipeline, so that the cooling water can be used for rapid cooling when necessary, thereby improving the crystallization efficiency of citric acid.

[0036] As shown in the figure, Figure 1 As shown in the figure, in order to facilitate the control of the system, valves are arranged on the pipelines in the system, so as to facilitate the fine reaction process control.

[0037] As shown in the figure, Figure 1 As shown in the figure, in order to improve the preparation efficiency of citric acid, the acidolysis tank 1 and the crystallization tank 5 are provided with stirring devices, so as to accelerate the flow of materials in the tank and improve the reaction rate.

[0038] Finally, it should be pointed out that the above is only the preferred embodiment of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A citric acid extraction and purification system, characterized in that, The system comprises, in sequence, an acid hydrolysis tank (1), a filtration device (2), an ion exchanger (3), a plate evaporator (4), a crystallizer (5), a centrifuge (6), and a fluidized bed (7), wherein: The acid hydrolysis tank (1) is provided with a raw material inlet (11) and a strong acid inlet (12) at the upper end. The raw material inlet (11) is connected to the calcium citrate salt supply pipeline, and the strong acid inlet (12) is connected to the sulfuric acid supply pipeline. The acid hydrolysis tank (1) is provided with a discharge port at the lower end, which is connected to the feed port of the filter device (2) through a pipeline. The discharge port of the filter device (2) is connected to the feed port of the ion exchanger (3) through a pipeline. The discharge port of the ion exchanger (3) is connected to the feed port of the plate evaporator (4) through a pipeline. The air inlet of the plate evaporator (4) is connected to the high temperature steam supply pipeline. The plate evaporator (4) is connected to the feed port of the crystallizer (5) through a pipeline. The discharge port of the crystallizer (5) is connected to the feed port of the centrifuge (6) through a pipeline. The discharge port of the centrifuge (6) is connected to the feed port of the fluidized bed (7) through a pipeline.

2. The citric acid extraction and purification system according to claim 1, characterized in that: The filtration device (2) is one or a combination of plate and frame filter and belt filter.

3. The citric acid extraction and purification system according to claim 1, characterized in that: The ion exchanger (3) consists of at least two sets of resin tanks (31) arranged in parallel, and the resin tanks (31) are equipped with resin beds and water distribution devices.

4. The citric acid extraction and purification system according to claim 1, characterized in that: The plate evaporator (4) is a triple-effect plate evaporator.

5. The citric acid extraction and purification system according to claim 4, characterized in that: The exhaust port of the plate evaporator (4) is connected to the condenser and the air inlet of the plate evaporator (4) respectively through pipes.

6. The citric acid extraction and purification system according to claim 1, characterized in that: The crystallization tank (5) is provided with a jacket (51), which can be connected to a cooling water supply pipe.

7. The citric acid extraction and purification system according to claim 1, characterized in that: Valves are installed on all the pipes in the system.

8. The citric acid extraction and purification system according to claim 1, characterized in that: The acid hydrolysis tank (1) and the crystallization tank (5) are equipped with stirring devices.

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