Calcium formate crystallization production line and working method thereof
By integrating feeding, reaction, separation, and impurity removal systems, continuous production of calcium formate and complete removal of impurities have been achieved, solving the problems of discontinuous production, high energy consumption, and environmental pollution in traditional production, and improving product quality and equipment efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG TIANTAI YUANYANG FOOD TECH CO LTD
- Filing Date
- 2026-05-26
- Publication Date
- 2026-07-03
AI Technical Summary
Traditional calcium formate production equipment suffers from problems such as discontinuous production process, incomplete impurity treatment, high energy consumption, and serious environmental pollution, resulting in low output, poor product quality, and serious material loss.
The integrated design of the feeding system, reaction system, separation system, impurity removal system and mother liquor circulation system enables continuous production and complete removal of impurities. The design of multiple reactors in series and a double-reactor structure with a stirred tank, combined with a settling tank and an evaporation tank, reduces material loss and energy consumption.
This technology enables continuous production of calcium formate, improves product quality, reduces energy consumption and environmental pollution, minimizes material loss, and enhances equipment utilization and production efficiency.
Smart Images
Figure CN122321764A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of calcium formate production technology, specifically to a calcium formate crystallization production line and its operating method. Background Technology
[0002] The main method for producing calcium formate is to react formic acid solution with calcium carbonate to produce calcium formate product solution. After filtration to remove insoluble matter from the product solution, the filtrate is concentrated, crystallized, centrifuged, and dried to obtain calcium formate product.
[0003] Patent CN119285460A discloses a method for efficient evaporation crystallization of calcium formate, comprising the following steps: S1, a mixed reaction using a first reactor, a second reactor, and a third reactor. Formic acid solution and calcium carbonate powder are continuously added to the first reactor and stirred until homogeneous for reaction. The reactants at the bottom of the first reactor are pressurized into the second reactor from the bottom. The reactants at the top of the second reactor overflow into the third reactor. The generated high-concentration calcium formate material accumulates at the bottom of the third reactor, while water-insoluble impurities float at the top of the third reactor; S2, impurity removal: the synthesis liquid is discharged into a purification vessel. First, it is heated to 900°C at 101.325 kPa to remove calcium carbonate from the synthesis liquid. Then, after the synthesis liquid cools down, the calcium carbonate is prepared... Heavy metal capture microspheres precipitate and remove heavy metals from the synthesis solution; S3, Evaporation and Crystallization: A triple-effect evaporator crystallizes the filtered trihydroxy condensate through multiple stages of dehydration. The triple-effect evaporator removes some water from the trihydroxy condensate, the second-effect evaporator concentrates the trihydroxy condensate to saturation, and the first-effect evaporator controls the crystallization of calcium formate, ensuring that 80%–90% of the calcium formate by mass precipitates as crystals; S4, Centrifugal Drying: The material from the first-effect evaporator is sent to a centrifuge for solid-liquid separation. The liquid enters the sedimentation process, while the crystals are conveyed to an airflow dryer via a screw feeder. The airflow contacts the crystals and evaporates the moisture, before entering the packaging process; S5, Cooling and Packaging: In the packaging process, the crystals are first cooled in a cooler, then conveyed to a cooling cyclone separator to lower the crystal temperature to 40°C, ensuring uniform product particle size for packaging. Its disadvantage is the high energy consumption due to the use of triple-effect evaporation.
[0004] Traditional calcium formate production equipment is a batch 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 ensure a complete reaction. Feeding is stopped after the appropriate liquid level is reached according to the reactor volume. The reactants continue to react in the reactor for approximately 2.5 hours. After the reaction liquid composition meets the standards, the product solution is pumped to a scraper centrifuge. After centrifugation, the material is conveyed to a dryer, and the dried finished product is conveyed to a silo by a scraper conveyor, packaged according to specifications, and sold.
[0005] The aforementioned traditional calcium formate production equipment has the following problems: First, in traditional equipment, there are time intervals between feeding, reaction, and discharge in the production process, which means that the reaction process cannot be carried out continuously. From the start of feeding into the reactor to the cessation of the reaction, the total time to complete one reactor reaction is about 4 hours, which is time-consuming, resulting in low equipment output, low production, and high energy consumption.
[0006] Secondly, the water-insoluble content of calcium formate is a core indicator for calcium formate products. Incomplete removal of impurities affects the whiteness of the product, hindering market development. Water-insoluble matter mainly originates from impurities in the calcium carbonate raw material. These impurities accumulate in the reactor along with the calcium carbonate, resulting in poor crystallization and small crystal size. In traditional equipment, to reduce the water-insoluble content, the product solution needs to be allowed to settle in the reactor for about 0.5 hours to remove the upper layer of water-insoluble matter and impurities. This disrupts the continuous reaction process, is time-consuming, and the discharge of water-insoluble matter and impurities can easily lead to the loss of calcium formate product, resulting in significant material waste. Furthermore, when restarting the stirring device after the product solution has settled in the reactor, impurity deposits often cause difficulty in starting the stirring device, potentially burning out the motor.
[0007] Third, the water introduced into the system by the formic acid and the water produced by the reaction will cause the mother liquor to be in excess. In traditional equipment, the mother liquor needs to be discharged intermittently according to the liquid level. The discharge of excess water can also easily cause the loss of calcium formate product in the mother liquor. Some manufacturers also use evaporation to treat the excess mother liquor, but the evaporation volume is large, the energy consumption is high, and the steam after evaporation also contains formic acid, which causes great environmental pollution. Summary of the Invention
[0008] To solve the above-mentioned technical problems, the present invention provides a calcium formate crystallization production line and its working method, which realizes continuous production, thorough impurity treatment, minimal material loss, low environmental pollution, and improved product quality.
[0009] The technical solution adopted in this invention is as follows.
[0010] A calcium formate crystallization production line includes a feeding system, a reaction system, a separation system, a purification system, a mother liquor circulation system, and a hot air system.
[0011] The feeding system includes a material pool, a first conveying device, a crushing and screening device, a second conveying device, and a high-level silo connected in sequence; the material pool contains calcium carbonate granules.
[0012] The reaction system includes a formic acid tank and several reaction groups. Each reaction group includes a weighing tank, a reaction vessel, and a heated stirring vessel connected in sequence by pipelines. Each reaction vessel is connected to the formic acid tank by pipelines. Each weighing tank is connected to a high-level chamber. Each reaction vessel is equipped with a first stirrer and a heating device.
[0013] The separation system includes a transfer tank and a centrifuge. Each insulated stirring vessel, transfer tank, and centrifuge is connected in sequence through pipelines.
[0014] The impurity removal system includes a filter, a settling tank, an evaporator, and an absorption tower. The filter is connected to the liquid outlet of the centrifuge via a pipeline. The top of the settling tank is connected to the filter via a pipeline. An overflow hole is provided at a certain height on the side wall of the settling tank. The overflow hole, the evaporator, and the absorption tower are connected in sequence via pipelines. A slag discharge door is provided on the bottom surface of the settling tank. An overflow port is provided at a certain height on the side wall of each reactor. Each overflow port is connected to the evaporator via a pipeline.
[0015] The mother liquor circulation system includes a high-level tank, which is connected to each reactor via pipelines; the bottom of the side wall of the settling tank is provided with a liquid outlet, which is connected to the material pool via pipelines and to the high-level tank via pipelines.
[0016] The hot air system includes a hot air furnace and a drying device located on the first conveying device, with the hot air furnace connected to the drying device.
[0017] Its beneficial effects are as follows.
[0018] 1. The feeding system provides continuous conveying and allows multiple reactors to react simultaneously. It employs a dual-reactor continuous reaction structure consisting of a reactor and a heated stirred tank. Formic acid solution and calcium carbonate are continuously and gradually fed into the reactor according to the real-time reaction ratio. After stirring and mixing, the mixture is immediately conveyed to the heated stirred tank for further reaction. Each heated stirred tank alternately feeds material to the transfer tank. The continuous stirring in the transfer tank eliminates the time intervals between feeding, reaction, and discharging in traditional intermittent production, avoiding the inefficiency of long reaction times in a single reactor that prevents continuous production, and eliminating the time intervals in intermittent production.
[0019] 2. By allowing the liquid rich in light impurities flowing out of the reactor overflow port to flow into the evaporator, product quality is improved and product whiteness is guaranteed; the filter removes the mother liquor, and the method of overflowing floating impurities from the settling tank and regularly cleaning the bottom sediment thoroughly removes impurities from the reused mother liquor.
[0020] 3. The production process involves constant stirring, eliminating the need for traditional sedimentation and waiting steps. This avoids the difficulties in starting the stirring device and the risk of motor burnout caused by impurities or crystallization.
[0021] 4. Part of the mother liquor from the settling tank is circulated to the reactor from the high-level tank, while the rest of the feed tank participates in the reaction, reducing material loss from the discharge of excess mother liquor; the overflowing liquid with suspended impurities is concentrated in the evaporator, and the steam is treated by the absorption tower. Compared with the traditional evaporation of a large amount of mother liquor, the energy consumption is lower, and the pollution of formic acid vapor to the environment is reduced.
[0022] 5. Calcium carbonate granules are dried with hot air during the conveying process, which reduces the moisture brought into the system, helps control the amount of mother liquor, and reduces the energy consumption of subsequent evaporation and the risk of material loss.
[0023] As a preferred technical solution, each pipeline is equipped with a liquid pump.
[0024] As a preferred technical solution, the reactor and the weighing tank are connected by a first feeding auger.
[0025] As a preferred technical solution, the first conveying device includes a mesh conveyor belt, and the drying device is equipped with a hot air duct with several nozzles. The hot air furnace is connected to the hot air duct via heat pipes. When the calcium carbonate granules move on the conveyor belt, the hot air sprayed through the nozzles vertically penetrates the calcium carbonate granule layer to evaporate the moisture.
[0026] As a preferred technical solution, the second conveying device includes a suction pipe and a pump connected to the suction pipe. The pump is installed at the top of the high-level silo, and the suction pipe is connected to the discharge port of the crushing and screening device.
[0027] As a preferred technical solution, each insulated stirring vessel is equipped with a third stirrer.
[0028] As a preferred technical solution, each weighing trough is connected to the bottom of the high-level silo, and each weighing trough is located below the high-level silo; the bottom of the high-level silo is provided with a high-level silo outlet, which is connected to the bottom of the second feeding auger, and the top of the second feeding auger is connected to the powder temporary storage silo; the top of each weighing trough is connected to the powder temporary storage silo through a third feeding auger; each weighing trough is located above each reaction vessel.
[0029] As a preferred technical solution, the formic acid tank is located above each reaction vessel.
[0030] As a preferred technical solution, the transfer tank is located below each reactor.
[0031] The operating method of any of the above-mentioned calcium formate crystallization production lines includes the following steps.
[0032] Step 1: Calcium carbonate granules are conveyed from the material pool to the crushing and screening device through the first conveying device. During the conveying process, the hot air furnace is started, and the calcium carbonate granules in the first conveying device are dried by the drying device. Step 2: The dried calcium carbonate granules are crushed into calcium powder by a crushing and screening device, and then transported to a high-level silo for temporary storage by a second conveying device. Step 3: Calcium powder in the high-level silo is quantitatively transferred to the corresponding weighing tank for weighing and then gradually fed into the reaction vessel. Formic acid from the formic acid tank is gradually fed into the reaction vessel to react and generate a calcium formate mixture. The first stirrer is always working during the process. Step 4: After the reaction is complete, the calcium formate mixture is discharged from the bottom of the reactor into a heat-insulated stirred tank to continue the reaction; after the liquid in each heat-insulated stirred tank has completed the reaction, it is supplied to the transfer tank one by one, and the second stirrer in the transfer tank stirs the mixture continuously; the mixture in the transfer tank is transported to a centrifuge for solid-liquid separation, the separated solid calcium formate crude product enters the subsequent drying process, and the separated liquid is sent to a filter to filter insoluble impurities; Step 5: The filtered liquid is sent to a settling tank for settling. When the sediment at the bottom of the settling tank accumulates to a certain amount, it is discharged from the slag outlet. During the settling process, impurities with a density lower than water gather on the liquid surface and overflow from the overflow hole on the side wall of the settling tank into the evaporator for evaporation and concentration. The steam generated by evaporation is sent to the absorption tower for tail gas treatment. Step 6: In the settling tank, part of the mother liquor is transferred to the high-level tank and then flows into each reaction vessel for recycling; the remainder is transferred to the material pool to react with the calcium carbonate particles. Step 7: Repeat the above steps. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of a preferred embodiment of the calcium formate crystallization production line of the present invention.
[0034] Figure 2 yes Figure 1 A magnified view of part A.
[0035] Figure 3 yes Figure 1 A magnified view of part B.
[0036] Figure 4 yes Figure 1 A magnified view of part C.
[0037] Figure 5 yes Figure 4 A magnified view of part D.
[0038] Figure 6 yes Figure 5 A magnified view of part G.
[0039] Figure 7 yes Figure 5 A magnified view of part H.
[0040] Figure 8 yes Figure 5 A magnified view of part I.
[0041] Figure 9 yes Figure 4 A magnified view of part E.
[0042] Figure 10 yes Figure 4 A magnified view of part F.
[0043] Wherein: material pool-1; first conveying device-11; conveyor belt-111; crushing and screening device-12; second conveying device-13; suction pipe-131; material and liquid pump-132; High-level storage -14; Calcium carbonate granules -15; Formic acid tank-2; First feeding auger-20; Weighing tank-21; Reactor-22; Insulated stirring vessel-221; Third pipeline-222; Third pump-223; Third stirrer-224; Ninth liquid pump - 23; Ninth pipeline - 24; First agitator - 25; Second feeding auger - 26; Powder temporary storage bin - 27; Third feeding auger - 28; Overflow port - 29; Fourth pipeline - 210; Fourth liquid pump - 211; Transfer tank-3; Centrifuge-31; First pipeline-32; Second stirrer-33; First pump-34; Second pipeline-35; Second pump-36; Tenth pipeline-37; Tenth pump-38; Filter-4; Settling tank-41; Evaporator-42; Absorption tower-43; Eleventh pump-44; Overflow hole-45; Fifth pipeline-46; Slag outlet-47; Filter outlet-48; Sixth pump-49; Sixth pipeline-410; Seventh pipeline-411; Seventh pump-412; Fifth pump-413; Eleventh pipeline-414; High-level tank-5; Eighth pump-51; Eighth pipeline-52; Hot air furnace-6; Drying device-61; Hot air duct-62; Spray nozzle-63; Heat pipe-64. Detailed Implementation
[0044] The present invention will now be further described in conjunction with the accompanying drawings and embodiments.
[0045] Example 1. As... Figure 1-8 As shown, a calcium formate crystallization production line includes a feeding system, a reaction system, a separation system, a purification system, a mother liquor circulation system, and a hot air system.
[0046] The feeding system includes a material pool 1, a first conveying device 11, a crushing and screening device 12, a second conveying device 13, and a high-level silo 14 connected in sequence; the material pool 1 contains calcium carbonate granules 15.
[0047] The reaction system includes formic acid tank 2 and several reaction groups.
[0048] Each reaction group includes a weighing tank 21, a reaction vessel 22, and a heated stirring vessel 221 connected in sequence by pipelines. Each reaction vessel 22 is connected to the formic acid tank 2 by pipelines; each weighing tank 21 is connected to the high-level chamber 14; each reaction vessel 22 is equipped with a first stirrer 25 and a heating device.
[0049] The separation system includes a transfer tank 3 and a centrifuge 31. Each insulated stirring vessel 221, transfer tank 3, and centrifuge 31 are connected in sequence through pipelines.
[0050] The impurity removal system includes a filter 4, a settling tank 41, an evaporator 42, and an absorption tower 43. The filter 4 is connected to the liquid outlet of the centrifuge 31 via a pipeline. The top of the settling tank 41 is connected to the filter 4 via a pipeline. An overflow hole 45 is provided at a certain height on the side wall of the settling tank 41. The overflow hole 45, the evaporator 42, and the absorption tower 43 are connected in sequence via pipelines. A slag discharge door 47 is provided on the bottom surface of the settling tank 41. An overflow port 29 is provided at a certain height on the side wall of each reaction vessel 22. Each overflow port 29 is connected to the evaporator 42 via a pipeline. The filter 4 is used to filter the mother liquor coming out of the centrifuge 31 and remove impurities that do not react with formic acid.
[0051] The mother liquor circulation system includes a high-level tank 5, which is connected to each reactor 22 via pipelines; the bottom of the side wall of the settling tank 41 is provided with a liquid outlet 48, which is connected to the material pool 1 via pipelines, and the liquid outlet 48 is connected to the high-level tank 5 via pipelines.
[0052] The hot air system includes a hot air furnace 6 and a drying device 61 located on the first conveying device 11. The hot air furnace 6 is connected to the drying device 61.
[0053] The reaction system includes formic acid tank 2 and two reaction groups. In another example, the reaction system includes three or more reaction groups.
[0054] Each pipeline is equipped with a liquid pump.
[0055] like Figure 4 As shown, the transfer tank 3 is connected to the centrifuge 31 through the second pipeline 35, and the second pipeline 35 is equipped with a second liquid pump 36.
[0056] like Figure 5 As shown, the high-level tank 5 is connected to each reaction vessel 22 through the eighth pipeline 52; the eighth pipeline 52 is equipped with the eighth liquid pump 51.
[0057] like Figure 6 As shown, each overflow port 29 is connected to the evaporator 42 via a fourth pipe 210, and each fourth pipe 210 is equipped with a fourth liquid pump 211. Each reaction vessel 22 is connected to the formic acid tank 2 via a ninth pipe 24; the ninth pipe 24 is equipped with a ninth liquid pump 23.
[0058] like Figure 7-8 As shown, the bottom of each insulated stirring vessel 221 is connected to the transfer tank 3 via a first pipeline 32, and a first liquid pump 34 is provided on each first pipeline 32. The top of each insulated stirring vessel 221 is connected to the reaction vessel 22 via a third pipeline 222, and a third liquid pump 223 is provided on the third pipeline 222.
[0059] like Figure 9 As shown, the overflow hole 45, the evaporator 42, and the absorption tower 43 are connected in sequence through the fifth pipeline 46; a fifth liquid pump 413 is provided on the fifth pipeline 46 between the overflow hole 45 and the evaporator 42.
[0060] The outlet 48 of the settling tank is connected to the material pool 1 through the sixth pipeline 410; the sixth pipeline 410 is equipped with a sixth pumping pump 49.
[0061] The outlet 48 of the settling tank is connected to the high-level tank 5 through the seventh pipeline 411; the seventh pipeline 411 is equipped with a seventh pump 412.
[0062] Each reactor 22 is equipped with a thermometer.
[0063] like Figure 2-3 As shown, the first conveying device 11 includes a mesh conveyor belt 111, and the drying device 61 is equipped with a hot air duct 62. The hot air duct 62 has several nozzles 63. When the calcium carbonate granules 15 move on the conveyor belt, the hot air sprayed through the nozzles 63 vertically penetrates the layer of calcium carbonate granules 15 to evaporate moisture. The hot air furnace 6 is connected to the hot air duct 62 via a heat pipe 64. The mesh conveyor belt and the vertical nozzle design allow the hot air to penetrate the calcium carbonate granule layer evenly, achieving all-around drying of the granules. Compared with traditional surface drying methods, this method has higher drying efficiency. It can reduce the moisture content of the calcium carbonate granules and reduce the excess mother liquor in the reaction system.
[0064] like Figure 3 As shown, the second conveying device 13 includes a suction pipe 131 and a pump 132 connected to the suction pipe 131. The pump 132 is installed at the top of the high-level silo 14, and the suction pipe 131 is connected to the discharge port of the crushing and screening device 12. The pump 132 conveys calcium carbonate powder to the high-level silo 14 through vacuum pumping.
[0065] like Figure 5 As shown, the reactor 22 and the weighing tank 21 are connected by the first feeding auger 20.
[0066] like Figure 7-8 As shown, each insulated stirring vessel 221 is equipped with a third stirrer 224.
[0067] like Figure 3-5As shown, each weighing trough 21 is connected to the bottom of the high-level silo 14, and each weighing trough 21 is located below the high-level silo 14. The bottom of the high-level silo 14 is provided with a high-level silo outlet 141, which is connected to the bottom of the second feeding auger 26. The top of the second feeding auger 26 is connected to the powder temporary storage silo 27. The top of each weighing trough 21 is connected to the powder temporary storage silo 27 through a third feeding auger 28. Each weighing trough 21 is located above each reactor 22. By setting the powder temporary storage silo as an intermediate buffer unit, the feeding rhythm from the high-level silo to each weighing trough can be balanced, avoiding insufficient or excessive feeding of a single reactor due to fluctuations in the discharge from the high-level silo. The third feeding auger is independently connected to each weighing trough, and combined with the metering function of the weighing trough, the amount of calcium carbonate fed into each reactor can be accurately controlled. The weighing trough is located above the reactor, and gravity can be used to achieve direct feeding of materials.
[0068] Formic acid tank 2 is located above each reactor 22. The formic acid tank's location above each reactor allows for the use of gravitational potential energy to assist in formic acid transport, reducing the operating energy consumption of the ninth pump. Under gravity, the formic acid droplet acceleration rate is stable, which is beneficial for the uniform mixing of formic acid and calcium carbonate within the reactor.
[0069] The transfer tank 3 is located below each reactor 22.
[0070] like Figure 4 As shown, the transfer tank 3 is connected to the centrifuge 31 through the second pipeline 35, and the second pipeline 35 is equipped with a second liquid pump 36.
[0071] like Figure 9 As shown, a fifth liquid pump 413 is installed on the fifth pipeline 46 between the overflow hole 45 and the evaporator 42.
[0072] like Figure 6 , Figure 10 As shown, each reactor 22 has an overflow port 29 at a certain height on its side wall. The overflow port 29 is 3 cm above the top of the reactor 22.
[0073] like Figure 4 As shown, centrifuge 31 and filter 4 are connected via a tenth pipe 37, and a tenth pump 38 is installed on the tenth pipe 37. Figure 9 As shown, the filter 4 is connected to the settling tank 41 through the eleventh pipeline 414, and the eleventh pipeline 414 is equipped with an eleventh liquid pump 44.
[0074] By setting up second and tenth pumps and corresponding valves, stable material transport can be achieved from the transfer tank to the centrifuge, from the centrifuge to the filter, etc. The fifth and fourth pumps can promptly transport the overflow liquid from the settling tank and the overflow liquid from the reaction vessel to the evaporation vessel for treatment, thus avoiding material accumulation.
[0075] The operating method of the calcium formate crystallization production line is characterized by including the following steps: Step 1: Calcium carbonate granules are conveyed from the material pool to the crushing and screening device through the first conveying device. During the conveying process, the hot air furnace is started, and the calcium carbonate granules in the first conveying device are dried by the drying device.
[0076] Step 2: The dried calcium carbonate particles are crushed into calcium powder by a crushing and screening device, and then transported to a high-level silo for temporary storage by a second conveying device.
[0077] Step 3: Calcium powder from the high-level silo is quantitatively transferred to the corresponding weighing tank, weighed, and then gradually fed into the reaction vessel. Formic acid from the formic acid tank is gradually fed into the reaction vessel, reacting to produce a calcium formate mixture. The first stirrer operates continuously throughout the process; the first stirrer speed is 60 r / min, and the reaction temperature is 60 degrees Celsius. The weight ratio of calcium carbonate to formic acid is approximately 1:0.83.
[0078] Step 4: After the reaction is complete, the calcium formate mixture is discharged from the bottom of the reactor into a heated stirred tank to continue the reaction. After the liquid in each heated stirred tank has completed the reaction, it is successively supplied to the transfer tank, where the second stirrer continuously stirs the mixture. The mixture in the transfer tank is then transported to a centrifuge for solid-liquid separation. The separated crude solid calcium formate enters the subsequent drying process, while the separated liquid is sent to a filter to remove insoluble impurities. The mixture is stirred in the heated stirred tank for 15–60 minutes. This process helps the crystals grow fully, forming uniform, free-flowing "flowing sand" calcium formate crystals. The stirrer speed is 60 r / min.
[0079] Step 5: The filtered liquid is sent to a settling tank for settling. When the sediment at the bottom of the settling tank accumulates to a certain amount, it is discharged from the slag outlet. During the settling process, impurities with a density lower than water gather on the liquid surface and overflow from the overflow hole on the side wall of the settling tank into the evaporator for evaporation and concentration. The steam generated by evaporation is sent to the absorption tower for tail gas treatment.
[0080] Step 6: In the settling tank, part of the mother liquor is transferred to the high-level tank and then flows into each reactor for recycling. The remainder is transferred to the material pool to react with the calcium carbonate particles.
[0081] Step 7: Repeat the above steps.
[0082] Its beneficial effects are as follows.
[0083] 1. The feeding system provides continuous conveying, allowing multiple reactors 22 to react simultaneously. It employs a dual-reactor continuous reaction structure consisting of reactor 22 and a heated stirring vessel 221. Formic acid solution and calcium carbonate are continuously and gradually fed into reactor 22 according to the real-time reaction ratio. After stirring and mixing, the mixture is immediately conveyed to the heated stirring vessel 221 to complete the deep reaction. Each heated stirring vessel 221 takes turns conveying materials to the transfer tank 3. The continuous stirring in the transfer tank 3 eliminates the time intervals between feeding, reaction, and discharging in traditional intermittent production, avoiding the inefficiency of long reaction times in a single reactor that prevents continuous production, and eliminating the time intervals in intermittent production.
[0084] 2. By using the method of allowing the liquid rich in light impurities flowing out of the overflow port 29 of the reaction vessel 22 to flow into the evaporation vessel 42, the product quality is improved and the whiteness of the product is guaranteed; the filter 4 filters the mother liquor, and combined with the overflow discharge of floating impurities from the settling tank 41 and the regular cleaning of the bottom sediment, the impurities in the reused mother liquor are thoroughly removed.
[0085] 3. The production process involves continuous stirring, eliminating the need for traditional sedimentation and waiting steps. This avoids the difficulties in starting the stirring device and the risk of motor burnout caused by impurities depositing or crystallizing.
[0086] 4. Approximately 25% of the mother liquor from the settling tank 41 is returned to the high-level tank 5 and circulated to the reactor 22, while the remainder is sent to the feeding tank 1 to participate in the reaction, reducing material loss from the discharge of excess mother liquor; the overflowing liquid with suspended impurities is concentrated in the evaporation reactor 42, and the steam is treated by the absorption tower 43. Compared with the traditional evaporation of a large amount of mother liquor, the energy consumption is lower, and the pollution of formic acid vapor to the environment is reduced.
[0087] 5. Calcium carbonate granules are dried with hot air during transportation, which reduces the moisture carried into the system, helps control the amount of mother liquor, and reduces the energy consumption of subsequent evaporation and the risk of material loss.
Claims
1. A calcium formate crystallization production line, characterized in that: It includes a feeding system, a reaction system, a separation system, a purification system, a mother liquor circulation system, and a hot air system; the feeding system includes a material pool, a first conveying device, a crushing and screening device, a second conveying device, and a high-level silo connected in sequence; the material pool contains calcium carbonate granules; The reaction system includes a formic acid tank and several reaction groups. Each reaction group includes a weighing tank, a reaction vessel, and a heated stirring vessel connected in sequence by pipelines. Each reaction vessel is connected to the formic acid tank by pipelines. Each weighing tank is connected to a high-level storage tank. Each reaction vessel is equipped with a first stirrer and a heating device. The separation system includes a transfer tank and a centrifuge. Each heated stirring vessel, transfer tank, and centrifuge is connected in sequence by pipelines. The impurity removal system includes a filter, a settling tank, an evaporator, and an absorption tower. The filter is connected to the liquid outlet of the centrifuge by pipelines. The top of the settling tank is connected to the filter by pipelines. An overflow hole is provided at a certain height on the side wall of the settling tank, and the overflow hole, evaporator, and absorption tower are connected in sequence by pipelines; a slag discharge door is provided on the bottom surface of the settling tank; an overflow port is provided at a certain height on the side wall of each reactor, and each overflow port is connected to the evaporator by pipelines; the mother liquor circulation system includes a high-level tank, which is connected to each reactor by pipelines; a liquid outlet is provided at the bottom end of the side wall of the settling tank, which is connected to the material pool by pipelines, and the liquid outlet is connected to the high-level tank by pipelines; the hot air system includes a hot air furnace and a drying device located on the first conveying device, and the hot air furnace is connected to the drying device.
2. The calcium formate crystallization production line as described in claim 1, characterized in that: Each pipeline is equipped with a liquid pump.
3. The calcium formate crystallization production line as described in claim 1, characterized in that: The reactor and the weighing tank are connected by the first feeding auger.
4. The calcium formate crystallization production line as described in claim 1, characterized in that: The first conveying device includes a mesh conveyor belt, the drying device is equipped with a hot air duct, the hot air duct is equipped with several spray holes, and the hot air furnace is connected to the hot air duct through a heat pipe.
5. The calcium formate crystallization production line as described in claim 1, characterized in that: The second conveying device includes a suction pipe and a pump connected to the suction pipe. The pump is installed at the top of the high-level silo, and the suction pipe is connected to the discharge port of the crushing and screening device.
6. The calcium formate crystallization production line as described in claim 1, characterized in that: Each insulated mixing vessel is equipped with a third agitator.
7. The calcium formate crystallization production line as described in claim 1, characterized in that: Each weighing trough is connected to the bottom of the high-level silo and is located below the high-level silo. The bottom of the high-level silo is provided with a high-level silo outlet, which is connected to the bottom of the second feeding auger. The top of the second feeding auger is connected to the powder temporary storage silo. The top of each weighing trough is connected to the powder temporary storage silo through a third feeding auger. Each weighing trough is located above each reaction vessel.
8. The calcium formate crystallization production line as described in claim 1, characterized in that: The formic acid tank is located above each reaction vessel.
9. The calcium formate crystallization production line as described in claim 1, characterized in that: The transfer tank is located below each reactor.
10. The working method of the calcium formate crystallization production line according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Calcium carbonate granules are conveyed from the material pool to the crushing and screening device through the first conveying device. During the conveying process, the hot air furnace is started, and the calcium carbonate granules in the first conveying device are dried by the drying device. Step 2: The dried calcium carbonate granules are crushed into calcium powder by a crushing and screening device, and then transported to a high-level silo for temporary storage by a second conveying device. Step 3: Calcium powder in the high-level silo is quantitatively transferred to the corresponding weighing tank for weighing and then gradually fed into the reaction vessel. Formic acid from the formic acid tank is gradually fed into the reaction vessel to react and generate a calcium formate mixture. The first stirrer is always working during the process. Step 4: After the reaction is complete, the calcium formate mixture is discharged from the bottom of the reactor into a heat-insulated stirred tank to continue the reaction; after the liquid in each heat-insulated stirred tank has completed the reaction, it is supplied to the transfer tank one by one, and the second stirrer in the transfer tank stirs the mixture continuously; the mixture in the transfer tank is transported to a centrifuge for solid-liquid separation, the separated solid calcium formate crude product enters the subsequent drying process, and the separated liquid is sent to a filter to filter insoluble impurities; Step 5: The filtered liquid is sent to a settling tank for settling. When the sediment at the bottom of the settling tank accumulates to a certain amount, it is discharged from the slag outlet. During the settling process, impurities with a density lower than water gather on the liquid surface and overflow from the overflow hole on the side wall of the settling tank into the evaporator for evaporation and concentration. The steam generated by evaporation is sent to the absorption tower for tail gas treatment. Step 6: In the settling tank, part of the mother liquor is transferred to the high-level tank and then flows into each reactor for recycling. The remainder is transferred to the material pool to react with the calcium carbonate particles. Step 7: Repeat the above steps.