A calcium formate continuous production device and process

Abstract

The present invention discloses a calcium formate continuous production device and process, belonging to the technical field of calcium formate production, the production device comprises a first reactor, a second reactor and a third reactor, the bottom of the first reactor is connected to the bottom of the second reactor through a first connecting pipe, the upper part of the second reactor is connected to the middle and lower part of the third reactor through a second connecting pipe, the bottom of the third reactor is connected to the feed port of a centrifuge through a pipeline, and the upper part of the third reactor is connected to the upper part of an impurity separation device through a first overflow port. The calcium formate continuous production device and process provided by the present invention adopts a multi-stage continuous reaction mode in which the bottoms of the first reactor and the second reactor are connected in series to transport materials, and the upper and bottom parts of the third reactor are discharged respectively, which fully prolongs the reaction time, has a thorough and sufficient reaction, has high production efficiency, has good product quality, reduces production cost and labor intensity, is easy to realize large-scale continuous production, and is suitable for wide promotion and application.

Description

Technical Field

[0001] The invention relates to a calcium formate continuous production device and process, and belongs to the technical field of calcium formate production. Background Art

[0002] The main method of producing calcium formate is to react formic acid solution with calcium carbonate to generate a calcium formate product solution, remove the insoluble matter in the product solution by filtration, and obtain the calcium formate product by concentrating, crystallizing, centrifuging, and drying the filtrate. The traditional calcium formate production process is an intermittent reaction. Formic acid solution and calcium carbonate are slowly added to the reactor according to the reaction ratio, and mixed with the added mother liquor by stirring to fully react. According to the volume of the reactor, the feeding is stopped after the feed reaches the appropriate liquid level. After the reaction material continues to react in the reactor for about 2.5 hours, the reaction liquid components are analyzed and meet the standards, and the product solution is transported to the scraper centrifuge by the feeding pump. After centrifugation, the material is transported to the dryer, and the dried finished product is transported to the silo by the scraper, and packaged according to specifications for sale.

[0003] The above-mentioned traditional production process of calcium formate has the following problems:

[0004] (1) In the traditional process, there is a time interval between feeding, reaction and discharging in the production process, which makes the reaction process unable to proceed continuously. From the start of feeding into the reactor to the stop of the reaction, the total time to complete a reactor reaction is about 4 hours, which is time-consuming, resulting in low equipment output rate, low output and high energy consumption.

[0005] (2) The content of water-insoluble matter in calcium formate is the core indicator of calcium formate products. If impurities are not removed properly, the whiteness of the calcium formate product will be affected, making market development difficult. Water-insoluble matter mainly comes from impurities in the calcium carbonate raw material. Impurities enter the reactor with calcium carbonate and aggregate, resulting in poor crystallization of calcium formate and small crystal size. In traditional processes, in order to reduce the content of water-insoluble matter, the product solution needs to be precipitated in the reactor for about 0.5 hours to discharge the water-insoluble matter and impurities in the upper layer, resulting in the inability to carry out the reaction continuously, which is time-consuming. In addition, the discharge of water-insoluble matter and impurities can easily cause the loss of calcium formate products, resulting in serious waste of materials.

[0006] (3) The water brought into the system by formic acid and the water produced as a by-product of the reaction will cause excess mother liquor. In the traditional process, the mother liquor needs to be discharged intermittently according to the mother liquor level. The discharge of excess water can easily cause the loss of calcium formate product in the mother liquor.

[0007] (4) In traditional processes, the filter cloth of the centrifuge used to separate calcium carbonate products needs to be cleaned regularly, usually once every five days, and each cleaning takes about four hours, which seriously restricts production capacity.

[0008] (5) The calcium formate obtained after centrifugation is dried in a dryer, and the generated water vapor enters a dust collector for treatment. The impurities contained in the calcium formate obtained in the traditional process are discharged with the air flow, resulting in a large amount of powder in the dust collector discharge.

[0009] It should be noted that the above contents belong to the technical knowledge of the inventor and do not necessarily constitute prior art. Summary of the invention

[0010] The purpose of the present invention is to solve the problems existing in the prior art. By providing a calcium formate continuous production device and process, large-scale continuous production can be achieved, the output of calcium formate is increased, the labor intensity is reduced, and the production cost is reduced.

[0011] The present invention achieves the above-mentioned purpose by adopting the following technical solutions:

[0012] In one aspect, the present invention provides a calcium formate continuous production device, comprising a first reactor, a second reactor, a third reactor, an impurity separation device, a filter press, an evaporator, a centrifuge and a mother liquid tank;

[0013] The bottom of the first reactor is connected to the bottom of the second reactor through a first connecting pipe, the upper part of the second reactor is connected to the middle and lower part of the third reactor through a second connecting pipe, the bottom of the third reactor is connected to the feed port of the centrifuge through a pipeline, and the upper part of the third reactor is connected to the upper part of the impurity separation device through a first overflow port;

[0014] The upper part of the impurity separation device is also connected to the feed port of the filter press through the second overflow port, and the bottom of the impurity separation device is connected to the third reactor;

[0015] The liquid outlet of the centrifuge is connected to the mother liquid tank through a pipeline;

[0016] The liquid outlet of the filter press is connected to the liquid inlet and / or the mother liquid tank of the evaporator through a pipeline, and the liquid discharge port of the evaporator is connected to the second reactor through a pipeline;

[0017] The mother liquor tank is also connected to the first reactor and / or the second reactor and / or the third reactor through a pipeline.

[0018] Optionally, the impurity separation device comprises a shell, in which a first baffle and a second baffle are vertically and alternately arranged, the left and right sides of the first baffle and the second baffle are fixedly connected to the side wall of the shell, and the bottom sides of the first baffle and the second baffle are spaced a certain distance from the bottom wall of the shell;

[0019] The first baffle and the second baffle are both provided with baffle openings at the top, the baffle openings on the first baffle and the baffle openings on the second baffle are arranged alternately, the position of the second overflow opening is lower than the position of the first overflow opening, and the position of the first overflow opening is lower than the top of the first baffle and the second baffle.

[0020] Optionally, the bottom wall of the shell is arranged obliquely downward in a direction close to the third reactor.

[0021] Optionally, a water inlet and a flushing outlet are provided at the lower portion of the shell, the water inlet is connected to a mother liquid at a certain pressure, and the flushing outlet is connected to the bottom of the third reactor.

[0022] Optionally, the liquid discharge port of the evaporator is connected to the bottom of the second reactor through a pipeline, and the mother liquid tank is connected to the bottom of the first reactor and / or the second reactor and / or the third reactor through a pipeline.

[0023] Optionally, the first reactor, the second reactor and the third reactor are provided with heating coils, and the first reactor, the second reactor, the third reactor and the mother liquid tank are provided with a stirrer.

[0024] Optionally, the calcium formate continuous production device also includes a first buffer tank and / or a second buffer tank, the upper part of the first buffer tank is connected to the second overflow port on the impurity separation device through a pipeline, the lower part of the first buffer tank is connected to the feed port of the filter press through a pipeline, the upper part of the second buffer tank is connected to the discharge port of the filter press through a pipeline, and the lower part of the second buffer tank is connected to the liquid inlet of the evaporator through a pipeline, and an agitator is provided in the first buffer tank and / or the second buffer tank.

[0025] Optionally, the centrifuge is a pusher-type centrifuge, and the filter press is a diaphragm filter press.

[0026] On the other hand, the present invention also provides a continuous production process of calcium formate, which uses a first reactor, a second reactor and a third reactor, continuously adds formic acid solution and calcium carbonate powder into the first reactor and stirs them evenly to react, the reaction material at the bottom of the first reactor is pressed into the second reactor from the bottom of the second reactor by pressure, and the reaction material at the top of the second reactor overflows into the third reactor;

[0027] The bottom reaction material is taken out from the bottom of the third reactor, and the crude calcium formate and the mother liquor are separated from the bottom reaction material, and the mother liquor is returned to the first reactor and / or the second reactor and / or the third reactor, and the crude calcium formate is dried and sieved to obtain the calcium formate product; the upper reaction material overflows from the upper part of the third reactor, and the water-insoluble matter entrained in the upper reaction material is separated from the upper reaction material to obtain a liquid phase, and the liquid phase is mixed with the mother liquor and returned to the first reactor and / or the second reactor and / or the third reactor, or the liquid phase is evaporated and concentrated and returned to the second reactor.

[0028] Optionally, the concentration of the formic acid solution used is 85-95%, the purity of calcium carbonate is greater than 95%, the weight ratio of the formic acid solution added to the first reactor to the calcium carbonate powder is (1.03-1.15):1, preferably 1.08:1; the material temperature in each reactor is 30-50°C, preferably 40°C; the pH value in each reactor is 3.5-4.

[0029] The calcium formate continuous production device and process provided by the present invention optimize the calcium formate production device and process and achieve the following beneficial effects:

[0030] (1) The positions of the feed port and the discharge port of each reactor are reasonably set, and a multi-stage continuous reaction mode is adopted in which the first reactor and the second reactor are connected in series to transport materials at the bottom, and the third reactor is discharged from the top and bottom respectively. The reaction materials are transported from the first reactor to the second reactor by using the pressure of the reaction materials themselves. After the reaction materials enter the second reactor, they are transported from the bottom to the top and overflow from the top to the third reactor, and finally taken out from the bottom of the third reactor, which fully prolongs the reaction time and ensures a thorough reaction;

[0031] (2) according to the required reaction time, the volume of the reaction materials in the reactor, the feeding rate of the formic acid solution and calcium carbonate, the discharge rate of the reaction materials, the reaction temperature and the pH value are reasonably determined, so that the circulation amount of the reaction materials in the system is increased, the solid-liquid ratio that the system can withstand is increased, the reaction is thorough and sufficient, and the particle size of the calcium formate product obtained is uniform;

[0032] (3) After solid-liquid separation and filtration, a portion of the liquid phase obtained from the upper discharge of the third reactor can be evaporated and concentrated to discharge the excess water in the system, effectively separating water-insoluble impurities and improving product purity. The liquid phase after evaporation and concentration can be returned to the second reactor with a higher concentration for continued crystallization, effectively recovering the calcium formate product in the upper discharge, thereby improving product yield;

[0033] (4) A stirrer is provided in the reactor to stir the reaction materials, which can not only make the materials mixed evenly and react fully, but also avoid the problem of accumulation of the reaction materials containing calcium formate in the reactor or clogging of the pipeline due to poor fluidity, thereby ensuring that the reaction can be carried out continuously; the stirrer in the third reactor is only provided with stirring blades at the bottom to stir and boost the reaction materials at the bottom, thereby avoiding stirring the reaction materials at the top and affecting the floating overflow effect of the water-insoluble substances in the reaction materials at the top, thereby improving the product purity;

[0034] (5) The mother liquor returns to each reactor through the pipeline to flush and boost the materials at the bottom of the reactor, allowing the materials to circulate smoothly in the system and prevent sedimentation and aggregation; in particular, the mother liquor returns to the first reactor and can also play a role in adjusting the solid-liquid ratio of the system materials.

[0035] In summary, the calcium formate continuous production device and process provided by the present invention have simple overall process, high production efficiency, good product quality, reduced production cost and labor intensity, easy to realize large-scale continuous production, and suitable for wide promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0037] Figure 1 A schematic diagram of the structure of a continuous production device for calcium formate provided in the present application;

[0038] Figure 2 A schematic diagram of the structure of an impurity separation device in a continuous calcium formate production device provided in the present application;

[0039] Figure 3 for Figure 2 Left view of

[0040] Figure 4 A schematic structural diagram of a first baffle and a second baffle in an impurity separation device in a calcium formate continuous production device provided by the present invention;

[0041] Figure 5 A three-dimensional schematic diagram of a partial structure of an impurity separation device in a calcium formate continuous production device provided in the present application;

[0042] Figure 6 A schematic diagram of the layout of the impurity separation equipment and the third reactor in the calcium formate continuous production device provided in the present application;

[0043] In the figure, 110, the first reactor; 120, the second reactor; 130, the third reactor; 140, the first connecting pipe; 150, the second connecting pipe; 160, the first overflow port; 170, the second overflow port; 101, the heating coil; 102, the agitator; 200, the centrifuge; 300, the mother liquor tank; 400, the impurity separation equipment; 410, the shell; 420, the first baffle; 430, the second baffle; 440, the baffle port; 450, the water inlet; 460, the flushing port; 500, the filter press; 600, the evaporator; 700, the dryer; 800, the first buffer tank; 900, the second buffer tank. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail in conjunction with the accompanying drawings in the following content. However, it should be pointed out that the following specific embodiments only provide specific operation examples of the present invention in an exemplary manner, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention is limited only by the claims. It is obvious to those skilled in the art that various other improvements and replacements can be made to the embodiments of the present invention within the protection scope defined by the claims of the present invention, and the same technical effects can still be achieved, thereby achieving the ultimate technical purpose of the present invention.

[0045] like Figure 1 As shown in, on the one hand, the present invention provides a calcium formate continuous production device, including a first reactor 110, a second reactor 120, a third reactor 130, an impurity separation device 400, a filter press 500, an evaporator 600, a centrifuge 200 and a mother liquid tank 300;

[0046] The bottom of the first reactor 110 is connected to the bottom of the second reactor 120 through the first connecting pipe 140, the upper part of the second reactor 120 is connected to the middle and lower part of the third reactor 130 through the second connecting pipe 150, the bottom of the third reactor 130 is connected to the feed port of the centrifuge 200 through a pipeline, and the upper part of the third reactor 130 is connected to the upper part of the impurity separation device 400 through the first overflow port 160;

[0047] The upper part of the impurity separation device 400 is also connected to the feed port of the filter press 500 through the second overflow port 170, and the bottom of the impurity separation device 400 is connected to the third reactor 130;

[0048] The liquid outlet of the centrifuge 200 is connected to the mother liquid tank 300 through a pipeline;

[0049] The liquid outlet of the filter press 500 is connected to the liquid inlet of the evaporator 600 and / or the mother liquid tank 300 through a pipeline, and the liquid outlet of the evaporator 600 is connected to the second reactor 120 through a pipeline;

[0050] Furthermore, the installation positions of the first reactor 110, the second reactor 120, and the third reactor 130 are successively lowered, and the first connecting pipe 140 between the first reactor 110 and the second reactor 120 and the second connecting pipe 150 between the second reactor 120 and the third reactor 130 are tilted downward downstream in the flow direction of the reaction material, so that the reaction material can be smoothly transported between the reactors in sequence. The specific production process is: formic acid solution and calcium carbonate powder are added into the first reactor 110 to start the reaction, and the reaction material in the first reactor 110 contains unreacted formic acid and calcium carbonate, calcium formate generated by the reaction, water brought in by the formic acid solution and the by-product of the reaction, and impurities brought in by the calcium carbonate powder. The reaction material continues to react while being pressed into the second reactor 120 from the bottom of the first reactor 110 by the liquid level difference. After entering the second reactor 120, the reaction material flows from bottom to top and overflows from the upper part of the second reactor 120 into the third reactor 130. The chemical reaction in the third reactor 130 has been basically completed, and the generated high-concentration calcium formate material is gathered at the bottom of the third reactor 130 , and the water-insoluble impurities float on the upper part of the third reactor 130 .

[0051] The bottom reaction material in the third reactor 130 is transported to the centrifuge 200 by the centrifuge 200 feeding pump, and the solid material obtained by centrifugation is a crude calcium formate. The centrifuge obtained by centrifugation enters the mother liquor tank 300 to be sent back to the reactor. The upper reaction material in the third reactor 130 overflows from the first overflow port 160 and enters the impurity separation device 400. In the impurity separation device 400, some water-insoluble impurities in the upper reaction material are separated and collected and enter the filter press 500. After the filter press 500 is filtered and impurities are removed, a part of the liquid phase obtained by the filter press 500 is directly collected in the mother liquor tank 300, and a part of it is sent to the second reactor 120 after the excess water is evaporated by the evaporator 600. It can be understood that the mother liquor contains formic acid, water and a small amount of calcium formate.

[0052] In order to effectively separate the water-insoluble impurities in the upper reaction material in the third reactor 130 from the mother liquor and discharge the surplus water in the upper reaction material, as Figure 2-Figure 5 As shown in , the impurity separation device 400 provided by the present application includes a shell 410, in which first baffles 420 and second baffles 430 are vertically alternately arranged, and the left and right sides of the first baffles 420 and the second baffles 430 are fixedly connected to the side wall of the shell 410, and the bottom sides of the first baffles 420 and the second baffles 430 are spaced from the bottom wall of the shell 410;

[0053] The first baffle 420 and the second baffle 430 are both provided with a baffle opening 440 at the top, the baffle opening 440 on the first baffle 420 and the baffle opening 440 on the second baffle 430 are arranged alternately, the position of the second overflow opening 170 is lower than the position of the first overflow opening 160, and the position of the first overflow opening 160 is lower than the top of the first baffle 420 and the second baffle 430.

[0054] After the upper reaction material overflows into the shell 410, it will flow to the lower second overflow port 170. During the flow process, calcium formate with high density gradually settles to the bottom of the shell 410, and water-insoluble impurities with low density float to the upper part. The arrangement of the first baffle 420 and the second baffle 430 can make the material flow in an S shape at the upper part of the shell 410, prolonging the flow time of the material and improving the separation effect. Water-insoluble impurities with low density overflow from the second overflow port 170 with the upper water and enter the filter press 500 for separation, and the resulting liquid phase enters the evaporator 600 to evaporate the excess water.

[0055] The number of the first baffle plate 420 and the second baffle plate 430 can be adjusted according to actual conditions. Figure 2 and Figure 5 The number of the first baffles 420 and the second baffles 430 shown in FIG. 4 is three in total.

[0056] In the shell 410 , calcium formate will settle to the bottom of the shell 410 . In order to gather calcium formate for easy cleaning and reduce dead corner accumulation in the shell 410 , in one embodiment, the bottom wall of the shell 410 is arranged obliquely downward toward the third reactor 130 .

[0057] Furthermore, in order to clean out the calcium formate accumulated at the bottom of the shell 410, in another embodiment, a water inlet 450 and a flushing outlet 460 are provided at the lower portion of the shell 410, the water inlet 450 is connected to a mother liquid at a certain pressure, and the flushing outlet 460 is connected to the bottom of the third reactor 130. During production, a high-pressure jet mother liquid is introduced into the shell 410 through the water inlet 450, and the mother liquid impacts the bottom of the shell 410, flushing the calcium formate and discharging it from the flushing outlet 460 into the third reactor 130, and then discharged from the third reactor 130 for centrifugal separation to obtain a crude calcium formate product.

[0058] Usually, if Figure 6 As shown in , the shell 410 is arc-shaped as a whole, and the shell 410 is wrapped around the 1 / 4 arc of the third reactor 130 . A plurality of overflow ports are opened on the upper part of the first reactor 110 to communicate with the shell 410 .

[0059] The liquid outlet of the filter press 500 is connected to the liquid inlet of the evaporator 600 and / or the mother liquid tank 300 through a pipeline. The liquid phase discharged from the filter press 500 has a high water content. A part of it is directly collected in the mother liquid tank 300, and a part of it is sent to the second reactor 120 after the excess water is evaporated by the evaporator 600. After the mother liquid is evaporated and concentrated, it returns to the second reactor 120 with a higher concentration to allow the calcium formate in the mother liquid to continue to crystallize. The mother liquid returns from the mother liquid tank 300 to each reactor through a pipeline to flush and boost the materials in the reactor, so that the materials can circulate smoothly in the system to prevent deposition and aggregation. In particular, the mother liquid returned to the first reactor 110 can also play a role in adjusting the solid-liquid ratio in the system materials.

[0060] Furthermore, the discharge port of the evaporator 600 is connected to the bottom of the second reactor 120 through a pipeline, and the liquid phase enters the second reactor 120 from the bottom of the second reactor 120 after being concentrated. The mother liquor tank 300 is connected to the bottom of the first reactor 110 and / or the second reactor 120 and / or the third reactor 130 through a pipeline, and the mother liquor enters the bottom of the reactor to focus on flushing the bottom material in the reactor.

[0061] Furthermore, a heating coil 101 is provided in the first reactor 110 , the second reactor 120 and the third reactor 130 , and an agitator 102 is provided in the first reactor 110 , the second reactor 120 , the third reactor 130 and the mother liquid tank 300 .

[0062] Specifically, steam is introduced into the heating coil 101 to control the reaction temperature in the reactor.

[0063] The use of the agitator 102 in the reactor can not only make the materials mixed evenly and fully react, but also promote the material transportation, solve the problem that the system cannot be smoothly produced due to high solid content, prevent material deposition or pipeline blockage, avoid shutdown for cleaning, and realize continuous production of feeding and discharging. The agitator 102 in the third reactor 130 is only provided with stirring blades at the bottom to stir and boost the reaction materials at the bottom, and the stirring speed should not be too fast to avoid stirring the upper reaction materials and affecting the floating overflow effect of the water-insoluble matter in the upper reaction materials, thereby improving the purity of the product.

[0064] The agitator 102 is installed in the mother liquid tank 300 to prevent the material from settling and accumulating, so that the material can be returned to the reactor for recycling, promote the continuous reaction, and reduce the difficulty of cleaning the mother liquid tank 300.

[0065] In a preferred embodiment, the calcium formate continuous production device provided by the present application further includes a first buffer tank 800 and / or a second buffer tank 900, the upper part of the first buffer tank 800 is connected to the second overflow port on the impurity separation device 400 through a pipeline, the lower part of the first buffer tank 800 is connected to the feed port of the filter press 500 through a pipeline, the upper part of the second buffer tank 900 is connected to the discharge port of the filter press 500 through a pipeline, and the lower part of the second buffer tank 900 is connected to the liquid inlet of the evaporator 600 through a pipeline, and the first buffer tank 800 and / or the second buffer tank 900 are provided with a stirrer 102 for stirring the material in the tank. The first buffer tank 800 is used to collect the clear liquid discharged from the impurity separation device 400, and the second buffer tank 900 is used to collect the discharge of the filter press 500.

[0066] In another embodiment, the calcium formate continuous production device provided by the present application further includes a dryer 700, which is used to dry the calcium formate solid discharged from the centrifuge 200. The bottom reaction material in the third reactor 130 is transported to the centrifuge 200 by the centrifuge 200 feeding pump, and the centrifuged material is transported to the dryer 700. The dried finished product is transported to the silo by a scraper conveyor and packaged according to specifications for sale.

[0067] The centrifuge 200 is preferably a pusher centrifuge 200 that can work continuously; the filter press 500 is preferably a membrane filter press 500 that can effectively separate water-insoluble impurities; and the evaporator 600 is preferably an MVR evaporator 600.

[0068] On the other hand, the present invention also provides a continuous production process of calcium formate, which uses a first reactor 110, a second reactor 120 and a third reactor 130, and continuously adds formic acid solution and calcium carbonate powder into the first reactor 110 and stirs them evenly to react, and the reaction material at the bottom of the first reactor 110 is pressed into the second reactor 120 from the bottom of the second reactor 120 by pressure, and the reaction material at the top of the second reactor 120 overflows into the third reactor 130;

[0069] The upper reaction material overflows from the upper part of the third reactor 130, and the bottom reaction material is taken from the bottom of the third reactor 130. The bottom reaction material mainly contains calcium formate, formic acid, and water. The crude calcium formate and mother liquor are separated from the bottom reaction material. The crude calcium formate is dried and sieved to obtain the calcium formate product. The upper reaction material mainly contains formic acid, water, a small amount of calcium formate, and floating water-insoluble impurities. The entrained water-insoluble impurities are separated from the upper reaction material to obtain a liquid phase. A portion of the liquid phase is returned to the first reactor and / or the second reactor and / or the third reactor, and a portion of the liquid phase is returned to the second reactor after evaporation and concentration.

[0070] The number of reactors is not limited to three, and can be increased according to the flow principle of the reaction materials in the present invention and the required reaction time and yield.

[0071] Furthermore, the concentration of the formic acid solution used is 85-95%, the purity of calcium carbonate is greater than 95%, the weight ratio of the formic acid solution added to the first reactor 110 to the calcium carbonate powder is (1.03-1.15):1, preferably 1.08:1; the material temperature in each reactor is 30-50°C, preferably 40°C; the pH value in each reactor is 3.5-4.

[0072] In order to more clearly explain the overall concept of the present application, a detailed description will be given below in the form of specific embodiments.

[0073] Embodiment 1:

[0074] The mass concentration of the formic acid solution used is 85%, the mass purity of the calcium carbonate powder used is 98%, and the height of the reactor is 3 meters.

[0075] The specific production process is:

[0076] (1) At the beginning of the reaction, 6 m 3 The mother liquor, formic acid solution at a rate of 2.1 tons / hour, and calcium carbonate at a rate of 2 tons / hour are continuously added, and the reaction is stirred until the liquid level rises to 2 / 3 of the reactor height, and the first connecting pipe 140 is opened to press the reaction materials containing unreacted formic acid and calcium carbonate, calcium formate generated by the reaction, water brought in by the formic acid solution and reaction by-products, and impurities brought in by the calcium carbonate powder into the second reactor 120, and at the same time, formic acid solution and calcium carbonate powder are continuously added to the first reactor 110; when feeding, accurate feeding is achieved through measuring instruments, and the addition amount of formic acid solution and calcium carbonate powder is strictly controlled, so that the feeding weight ratio per unit time is formic acid: calcium carbonate = 1.08:1. In order to ensure the impact of feeding deviation, feeding interval metering measures are taken to correct the deviation in time.

[0077] (2) After the reaction materials enter the second reactor 120, they flow upward from the upper part of the second reactor 120 and overflow into the third reactor 130. The upper reaction materials in the third reactor 130 overflow from the first overflow port 160 and enter the impurity separation device 400. In the impurity separation device, water-insoluble impurities float and overflow with the liquid phase, and after being collected, they enter the filter press 500. After being filtered and impurities are removed by the filter press 500, the obtained liquid phase is collected and directly enters the mother liquid tank 300 or is sent to the second reactor 120 after the excess water is evaporated by the evaporator 600. The evaporated wastewater is sent to the sewage station.

[0078] The bottom reaction material in the third reactor 130 is transported to the centrifuge 200 by the centrifuge 200 feeding pump, and the solid material obtained by centrifugation is a crude calcium formate, which is dried at 105° C. in a dryer 700 to obtain a calcium formate product. The centrifuged liquid is sent to the mother liquid tank 300 to be sent back to the reactor for reaction.

[0079] During the reaction, the amount of mother liquor returned to the reactor is controlled so that the solid-liquid ratio of the centrifuge 200 is about 30%. pH and other detection instruments are added to control the amount of formic acid solution added so that the pH value in the reactor is 3.5-4.

[0080] In the above steps, the stirring speed of the agitator 102 in the first reactor 110 and the second reactor 120 is usually 60r / min, and the stirring speed in the third reactor 130 is 40-60r / min. The stirring speed in the third reactor 130 is appropriately reduced, and the temperature of the steam introduced into the heating coil 101 is controlled so that the reaction temperature in each stage of the reactor reaches 35-50°C.

[0081] The performance indicators and yield indicators of the calcium formate product prepared in Example 1 are shown in Table 1 below.

[0082] Table 1

[0083] Calcium formate purity wt% Yield Calcium formate 60 mesh aperture pass rate % Product Appearance Example 1 99.8％ 90 tons / day 99.9％ Uniform white Traditional batch process 99％ 30 tons / day 90％ Poor chromaticity, uneven

[0084] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0085] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] The above specific implementation manner cannot be used as a limitation on the protection scope of the present invention. For those skilled in the art, any substitution, improvement or change made to the implementation manner of the present invention falls within the protection scope of the invention.

[0087] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A continuous production device for preparing calcium formate using formic acid and calcium carbonate as raw materials, characterized in that: It includes a first reactor, a second reactor, a third reactor, an impurity separation device, a filter press, an evaporator, a centrifuge and a mother liquid tank; The bottom of the first reactor is connected to the bottom of the second reactor through a first connecting pipe, the upper part of the second reactor is connected to the middle and lower part of the third reactor through a second connecting pipe, the bottom of the third reactor is connected to the feed port of the centrifuge through a pipeline, and the upper part of the third reactor is connected to the upper part of the impurity separation device through a first overflow port; The upper part of the impurity separation device is also connected to the feed port of the filter press through the second overflow port, and the bottom of the impurity separation device is connected to the third reactor; The liquid outlet of the centrifuge is connected to the mother liquid tank through a pipeline; The liquid outlet of the filter press is connected to the liquid inlet and / or the mother liquid tank of the evaporator through a pipeline, and the liquid discharge port of the evaporator is connected to the second reactor through a pipeline; The mother liquor tank is also connected to the first reactor and / or the second reactor and / or the third reactor through a pipeline.

2. The continuous production device according to claim 1, characterized in that: The impurity separation device comprises a shell, in which a first baffle and a second baffle are vertically and alternately arranged, the left and right sides of the first baffle and the second baffle are fixedly connected to the side wall of the shell, and the bottom sides of the first baffle and the second baffle are spaced a certain distance from the bottom wall of the shell; The first baffle and the second baffle are both provided with baffle openings at the top, the baffle openings on the first baffle and the baffle openings on the second baffle are arranged alternately, the position of the second overflow opening is lower than the position of the first overflow opening, and the position of the first overflow opening is lower than the top of the first baffle and the second baffle.

3. The continuous production device according to claim 2, characterized in that: The bottom wall of the shell is arranged obliquely downward toward the direction close to the third reactor.

4. The continuous production device according to claim 2, characterized in that: A water inlet and a flushing outlet are provided at the lower part of the shell, the water inlet is communicated with a mother liquid at a certain pressure, and the flushing outlet is communicated with the bottom of the third reactor.

5. The continuous production device according to claim 1, characterized in that: The liquid discharge port of the evaporator is connected to the bottom of the second reactor through a pipeline, and the mother liquid tank is connected to the bottom of the first reactor and / or the second reactor and / or the third reactor through a pipeline.

6. The continuous production device according to claim 1, characterized in that: The first reactor, the second reactor and the third reactor are provided with heating coils, and the first reactor, the second reactor, the third reactor and the mother liquid tank are provided with a stirrer.

7. The continuous production device according to claim 1, characterized in that: It also includes a first buffer tank and / or a second buffer tank, the upper part of the first buffer tank is connected to the second overflow port on the impurity separation device through a pipeline, the lower part of the first buffer tank is connected to the feed port of the filter press through a pipeline, the upper part of the second buffer tank is connected to the discharge port of the filter press through a pipeline, and the lower part of the second buffer tank is connected to the liquid inlet of the evaporator through a pipeline, and an agitator is arranged in the first buffer tank and / or the second buffer tank.

8. The continuous production device according to claim 1, characterized in that: The centrifuge is a pusher type centrifuge, and the filter press is a diaphragm filter press.

9. A continuous production process of calcium formate, characterized in that: A first reactor, a second reactor and a third reactor are used, formic acid solution and calcium carbonate powder are continuously added into the first reactor and stirred evenly for reaction, the reaction material at the bottom of the first reactor is pressed into the second reactor from the bottom of the second reactor by pressure, and the reaction material at the top of the second reactor overflows into the third reactor; The bottom reaction material is taken out from the bottom of the third reactor, and the crude calcium formate and the mother liquor are separated from the bottom reaction material, and the mother liquor is returned to the first reactor and / or the second reactor and / or the third reactor, and the crude calcium formate is dried and sieved to obtain the calcium formate product; the upper reaction material overflows from the upper part of the third reactor, and the water-insoluble matter entrained in the upper reaction material is separated from the upper reaction material to obtain a liquid phase, and the liquid phase is mixed with the mother liquor and returned to the first reactor and / or the second reactor and / or the third reactor, or the liquid phase is evaporated and concentrated and returned to the second reactor.

10. The continuous production process of calcium formate according to claim 9, characterized in that: The concentration of the formic acid solution used is 85-95%, the purity of calcium carbonate is greater than 95%, the weight ratio of the formic acid solution added to the first reactor to the calcium carbonate powder is (1.03-1.15):1, the material temperature in each reactor is 30-50°C, and the pH value in each reactor is 3.5-4.

Images