Production device of food-grade potassium chloride

Abstract

The utility model provides a production device of food-grade potassium chloride. The production device comprises a feeding unit, a hot melting and purifying unit, an evaporative crystallization unit, a thickening and dehydrating unit, a drying and packaging unit, a steam system for providing steam for the hot melting and purifying unit and the evaporative crystallization unit, and a condensate water system for providing condensate water for the hot melting and purifying unit, which are arranged in sequence, the production device of the food-grade potassium chloride is reasonable in process design, complete in process line, low in investment, low in energy consumption, low in production cost and stable in operation, and can produce the food-grade potassium chloride which is high in purity, good in quality, moderate in crystal granularity and approximately consistent with the granularity of edible salt through reasonable process control; when being used as a compound raw material of low-sodium salt, the low-sodium salt can be uniformly mixed with edible salt and is not easy to layer.

Description

Technical Field

[0001] The utility model belongs to the technical field of food-grade potassium chloride production, in particular to a production device for food-grade potassium chloride. Background Art

[0002] Potassium chloride is mainly used to make agricultural potassium fertilizers, and can also be used in food and medical fields. Food-grade potassium chloride is mainly concentrated in related industries such as food industry ingredients and additives, such as salt substitutes, nutritional supplements, gelling aids, yeast nutrients, etc. With the improvement of people's living standards, the demand for low-sodium salt products, condiments and other products in my country is also increasing rapidly, which will drive the steady growth of the consumption of upstream food-grade potassium chloride and other ingredients.

[0003] Food-grade potassium chloride products are generally made of industrial potassium chloride and other raw materials through processes such as dissolution, purification, crystallization, centrifugal separation, and drying. Industrial potassium chloride and other raw materials have high soluble and insoluble impurities, dark color, and poor appearance, so they must be further refined to produce food-grade potassium chloride. At present, when most manufacturers use industrial potassium chloride as raw materials to refine food-grade potassium chloride, their production line structure design is unreasonable, the purification and impurity removal effect is poor, and the crystallization process mostly uses cooling crystallization or flash crystallization, resulting in large investment and high energy consumption. The particle size uniformity of the food-grade potassium chloride produced is poor, the particle size is generally small, the fluidity is poor, and it is easy to agglomerate. Especially when used as a raw material for low-sodium salt, it has poor compatibility with edible salt when compounded, and it is easy to stratify and uneven mixing occurs. Summary of the invention

[0004] In view of this, in order to solve the above technical problems, the utility model proposes a production device for food-grade potassium chloride with reasonable structural design, low investment, low energy consumption, low production cost and stable operation. Through reasonable process control, food-grade potassium chloride with high purity, good quality and moderate crystal size, which is roughly consistent with the particle size of edible salt, can be produced. When used as a compound raw material for low-sodium salt, it can be evenly mixed with edible salt and is not easy to stratify.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A food-grade potassium chloride production device comprises a steam system, a condensed water system, and a feeding unit, a hot melt purification unit, an evaporation crystallization unit, a thickening and dehydration unit, and a drying and packaging unit which are arranged in sequence;

[0007] The discharge end of the feeding unit is connected to the feed end of the hot melt purification unit, and the feeding unit is used to feed the raw material potassium chloride into the hot melt purification unit for thermal dissolution;

[0008] The hot melt purification unit is used to heat dissolve the raw potassium chloride into a saturated potassium chloride solution at a certain temperature, and purify and remove impurities from the saturated potassium chloride solution after heat dissolution. The discharge end of the hot melt purification unit is connected to the feed end of the evaporation crystallization unit, and the purified and impurity-free potassium chloride solution is fed into the evaporation crystallization unit;

[0009] The evaporation and crystallization unit is used to evaporate and crystallize the purified and impurity-removed potassium chloride solution into potassium chloride slurry. The discharge end of the evaporation and crystallization unit is connected to the feed end of the thickening and dehydration unit to feed the potassium chloride slurry into the thickening and dehydration unit.

[0010] The thickening and dehydration unit is used to thicken and dehydrate the potassium chloride slurry. The discharge end of the thickening and dehydration unit is connected to the feed end of the drying and packaging unit to feed the thickened and dehydrated wet potassium chloride into the drying and packaging unit.

[0011] The drying and packaging unit is used to dry the thickened and dehydrated potassium chloride and package it into a food-grade potassium chloride product;

[0012] The steam system is used to provide the required steam to the hot melt purification unit and the evaporation crystallization unit;

[0013] The condensed water system is used to provide the required condensed water to the hot melt purification unit.

[0014] The raw potassium chloride is sent to the hot melt purification unit by the feeding unit. The condensed water system provides condensed water to the hot melt purification unit to dissolve the raw potassium chloride and prepare a saturated potassium chloride solution. After the saturated potassium chloride solution is purified and impurities are removed, it is sent to the evaporation and crystallization unit for evaporation and crystallization. The steam required for evaporation and crystallization is provided by the steam system. The obtained potassium chloride slurry is sent to the thickening and dehydration unit for further thickening and dehydration to obtain wet potassium chloride, and then sent to the drying and packaging unit for drying, screening and packaging to obtain a food-grade potassium chloride product.

[0015] Furthermore, the loading unit includes a crane and a bag unpacker. The crane lifts the ton bag of raw potassium chloride, and the bag unpacker opens the ton bag, and the raw potassium chloride falls into the feed end of the hot melt purification unit.

[0016] Furthermore, the hot melt purification unit includes a hot melt tank, a reagent tank, a clarification barrel, a filter, a filter press, and a refined brine barrel; the feed end of the hot melt tank corresponds to the discharge end of the loading unit, receives the raw potassium chloride provided by the loading unit, and the condensed water system provides condensed water for dissolving the raw potassium chloride to the hot melt tank; the discharge end of the hot melt tank is connected to the feed end of the clarification barrel through a raw brine pump; the clear liquid discharge end of the clarification barrel is connected to the feed end of the filter through a brine conversion pump, and the sludge discharge end of the clarification barrel is connected to the feed end of the filter press through a sludge pump; the liquid outlet end of the filter and the liquid outlet end of the filter press are connected to the feed end of the refined brine barrel; the refined brine barrel provides the evaporation and crystallization unit with the purified and impurity-removed potassium chloride solution through a feed pump; the reagent tank includes a potassium hydroxide reagent tank and a potassium carbonate reagent tank for adding reagents into the hot melt tank, and a hydrochloric acid reagent tank for adding reagents into the refined brine barrel.

[0017] Furthermore, the hot melt purification unit also includes a recovery system; an insulation pipe is provided on the refined brine barrel, the steam inlet of the insulation pipe is connected to the steam system, the steam system provides insulation steam for the refined brine barrel, the condensate outlet of the insulation pipe is connected to the recovery system, and the condensed water generated by the steam insulation is sent to the recovery system.

[0018] Furthermore, the filter is a membrane filter; the filter press is a plate and frame filter press; a stirring device is provided in the clarification barrel, the bottom of the inner cavity is an inclined bottom, the clear liquid discharge end of the clarification barrel is located on the side with a higher inclined bottom, and the sludge discharge end of the clarification barrel is located on the side with a lower inclined bottom.

[0019] Further, the evaporation crystallization unit includes a first-effect evaporation crystallization system, a second-effect evaporation crystallization system, a third-effect evaporation crystallization system, a salt slurry barrel and a mixed condensation system;

[0020] The single-effect evaporation crystallization system comprises a single-effect evaporation crystallization tank, a single-effect heating chamber, a single-effect circulation pump, a single-effect lower circulation pipe, a single-effect upper circulation pipe, and a single-effect salt foot; the single-effect salt foot is arranged at the conical bottom of the single-effect evaporation crystallization tank; the discharge port of the single-effect evaporation crystallization tank is connected to the feed port of the single-effect circulation pump through the single-effect lower circulation pipe; the discharge port of the single-effect circulation pump is connected to the feed port of the single-effect heating chamber, and the discharge port of the single-effect heating chamber is connected to the feed port of the single-effect evaporation crystallization tank through the single-effect upper circulation pipe;

[0021] The two-effect evaporation crystallization system comprises a two-effect evaporation crystallization tank, a two-effect heating chamber, a two-effect circulation pump, a two-effect lower circulation pipe, a two-effect upper circulation pipe, and a two-effect salt foot; the two-effect salt foot is arranged at the conical bottom of the two-effect evaporation crystallization tank; the discharge port of the two-effect evaporation crystallization tank is connected to the feed port of the two-effect circulation pump through the two-effect lower circulation pipe; the discharge port of the two-effect circulation pump is connected to the feed port of the two-effect heating chamber, and the discharge port of the two-effect heating chamber is connected to the feed port of the two-effect evaporation crystallization tank through the two-effect upper circulation pipe;

[0022] The triple-effect evaporation crystallization system comprises a triple-effect evaporation crystallization tank, a triple-effect heating chamber, a triple-effect circulation pump, a triple-effect lower circulation pipe, a triple-effect upper circulation pipe, and a triple-effect salt foot; the triple-effect salt foot is arranged at the conical bottom of the triple-effect evaporation crystallization tank; the discharge port of the triple-effect evaporation crystallization tank is connected to the feed port of the triple-effect circulation pump through the triple-effect lower circulation pipe; the discharge port of the triple-effect circulation pump is connected to the feed port of the triple-effect heating chamber, and the discharge port of the triple-effect heating chamber is connected to the feed port of the triple-effect evaporation crystallization tank through the triple-effect upper circulation pipe;

[0023] The bottom of the first-effect salt foot is provided with a salt slurry outlet, the upper outer side of the first-effect heating room is provided with a steam inlet, the upper part of the first-effect lower circulation pipe is provided with a potassium chloride solution inlet, and the top of the first-effect evaporation crystallization tank is provided with a secondary steam outlet; the bottom of the second-effect salt foot is provided with a salt slurry outlet, the upper outer side of the second-effect heating room is provided with a steam inlet, the upper part of the second-effect lower circulation pipe is provided with a potassium chloride solution inlet, the bottom of the second-effect lower circulation pipe is provided with a slurry transfer inlet, and the top of the second-effect evaporation crystallization tank is provided with a secondary steam outlet; the bottom of the triple-effect salt foot is provided with a salt slurry outlet, the upper outer side of the triple-effect heating room is provided with a steam inlet, the upper part of the triple-effect lower circulation pipe is provided with a potassium chloride solution inlet, the bottom of the triple-effect lower circulation pipe is provided with a slurry transfer inlet, and the top of the triple-effect evaporation crystallization tank is provided with a secondary steam outlet;

[0024] The steam system is connected to the steam inlet of the first-effect heating chamber to supply steam to the first-effect heating chamber, the secondary steam outlet of the first-effect evaporation crystallization tank is connected to the steam inlet of the second-effect heating chamber, the secondary steam outlet of the second-effect evaporation crystallization tank is connected to the steam inlet of the third-effect heating chamber, and the secondary steam outlet of the third-effect evaporation crystallization tank is connected to the mixed condensation system;

[0025] The discharge end of the refined brine barrel is connected to the potassium chloride solution inlet of the first effect lower circulation pipe, the potassium chloride solution inlet of the second effect lower circulation pipe, and the potassium chloride solution inlet of the third effect lower circulation pipe through a feed pump; that is, the saturated potassium chloride solution first enters the lower circulation pipe of each effect evaporation crystallization system, and then is pumped to the heating chamber of each effect by the circulation pump of each effect to heat the material, and then enters the evaporation crystallization tank of each effect through the upper circulation pipe of each effect to evaporate and precipitate potassium chloride crystals;

[0026] The salt slurry outlet of the first-effect salt foot is connected to the slurry transfer inlet of the second-effect lower circulation pipe, so that when a certain amount of solid potassium chloride crystals are produced in the first-effect evaporation crystallization tank, they can be transferred to the second-effect evaporation crystallization system at a certain solid-liquid ratio for circulation crystallization; the salt slurry outlet of the second-effect salt foot is connected to the slurry transfer inlet of the third-effect lower circulation pipe, so that when a certain amount of solid potassium chloride crystals are produced in the second-effect evaporation crystallization tank, they can be transferred to the third-effect evaporation crystallization system at a certain solid-liquid ratio for circulation crystallization; the salt slurry outlet of the third-effect salt foot is connected to the feed end of the salt slurry barrel for discharging the salt slurry; the slurry outlet end of the salt slurry barrel is connected to the feed end of the thickening and dehydration unit through a transfer pump.

[0027] Furthermore, the outlet ends of the first-effect upper circulation pipe, the second-effect upper circulation pipe, and the third-effect upper circulation pipe are all trumpet-shaped, and respectively extend into the interior of their corresponding evaporation crystallization tanks to realize an axial feeding method, which can ensure the smooth operation of the evaporation crystallization device of the device, uniform steam intensity, and facilitate the control of the size and uniformity of the crystallized particles.

[0028] Furthermore, the thickening and dehydration unit includes a thickener and a centrifuge; the salt slurry feed end of the thickener is connected to the slurry outlet end of the salt slurry barrel through a transfer pump, the salt slurry outlet end on the bottom side of the thickener is connected to the feed end of the centrifuge, the wet potassium discharge end of the centrifuge is connected to the feed end of the drying and packaging unit, and the mother liquor outlet of the centrifuge is connected to the recovery port of the refined brine barrel for collecting the removed mother liquor.

[0029] Furthermore, the inner cavity of the thickener is provided with a stirring device to prevent the potassium chloride slurry from clogging the salt slurry outlet and ensure stable operation of the device; a weighing sensor device is arranged under the outer leg to facilitate material weight measurement; a mother liquor brine outlet is arranged on the top side, and a clean potassium chloride solution inlet is arranged on the bottom; the mother liquor brine outlet of the thickener is connected to the recovery port of the salt slurry barrel, and the salt slurry barrel receives the mother liquor brine overflowed from the top side of the thickener; the clean potassium chloride solution inlet of the thickener is connected to the discharge end of the refined brine barrel, and the refined brine barrel supplies clean potassium chloride solution into the thickener to prevent the potassium chloride slurry from clogging the salt slurry outlet.

[0030] Furthermore, the drying and packaging unit includes a vibrating feeder, a drying system, a vibrating screen, a belt conveyor, a finished product silo and a packaging machine which are connected in sequence; the feed end of the vibrating feeder receives the thickened and dehydrated wet potassium chloride provided by the thickening and dehydration unit, the discharge end of the vibrating feeder is connected to the feed end of the drying system, the discharge end of the drying system is connected to the feed end of the vibrating screen, the discharge end of the vibrating screen is connected to the feed end of the belt conveyor, the discharge end of the belt conveyor is connected to the feed end of the finished product silo, and the discharge end of the finished product silo is connected to the feed end of the packaging machine.

[0031] Compared with the prior art, the production device of food-grade potassium chloride described in the utility model has the following advantages:

[0032] (1) The production process of food-grade potassium chloride described in the utility model is reasonably designed, the process line is complete, the investment is small, the energy consumption is low, the production cost is low, and the operation is stable. Through reasonable process control, food-grade potassium chloride with high purity, good quality, moderate crystal size, and substantially the same crystal size as edible salt can be produced. When used as a composite raw material for low-sodium salt, it can be evenly mixed with edible salt and is not easy to separate;

[0033] (2) The food-grade potassium chloride production device described in the utility model heat-dissolves the raw potassium chloride in a hot dissolving tank, adds reagents for reaction and clarification, and then sends it into a clarification tank for full reaction and clarification. The precipitate is fully reacted and deposited at the bottom, which reduces the burden of the subsequent filtration system. The upper clarified brine enters the filter for impurity removal again, and a pure saturated potassium chloride solution can be obtained to ensure that a food-grade potassium chloride product with high purity, potassium chloride content ≥99.6%, good quality, and white product color can be obtained later;

[0034] (3) The production device of food-grade potassium chloride described in the utility model adopts a single-effect, double-effect, and triple-effect evaporation and crystallization system. The pure saturated potassium chloride solution is divided into three streams and enters three evaporation tanks at the same time, which is evaporated and concentrated and crystallized to precipitate crystals. The secondary steam is reused multiple times, which saves energy and reduces consumption. The steam consumption per ton of potassium chloride product is not higher than 0.8 tons. The yield of potassium chloride in this device is high, which effectively reduces the production cost. Through reasonable process control, the transfer of slurry between tanks is used as a seed crystal, etc., and a food-grade potassium chloride product with a particle size roughly consistent with that of edible salt can be obtained. The particle distribution satisfies D10: 0.2mm, D90: 0.5mm, and the majority of the particles are 0.4-0.45mm. When used as a compound raw material for low-sodium salt, it can be well mixed with edible salt, is not easy to stratify, and has stable product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0036] Figure 1 This is a schematic diagram of the structure of a production device for food-grade potassium chloride according to an embodiment of the utility model;

[0037] Figure 2 This is a production flow chart of the production device of food-grade potassium chloride described in the embodiment of the utility model.

[0038] Description of reference numerals:

[0039] 1-traveling crane; 2-unpacking machine; 3-hot dissolving tank; 4-raw brine pump; 5-potassium hydroxide reagent tank; 6-potassium carbonate reagent tank; 7-clarification tank; 8-brine transfer pump; 9-sludge pump; 10-membrane filter; 11-plate and frame filter press; 12-fine brine barrel; 13-hydrochloric acid reagent tank; 14-feeding pump; 15-first-effect evaporation crystallization tank; 16-second-effect evaporation crystallization tank; 17-third-effect evaporation crystallization tank; 18-salt slurry barrel; 19-transfer pump; 20-thickener; 21-centrifuge; 22-vibrating feeder; 23-drying system; 24-vibrating screen; 25-belt conveyor; 26 -Finished product silo; 27-Packaging machine; 28-Weighing sensor device; 29-Mixed condensation system; 30-Steam system; 31-Condensate system; 32-Recovery system; 33-First-effect heating chamber; 34-First-effect circulation pump; 35-First-effect lower circulation pipe; 36-First-effect upper circulation pipe; 37-First-effect salt foot; 38-Second-effect heating chamber; 39-Second-effect circulation pump; 40-Second-effect lower circulation pipe; 41-Second-effect upper circulation pipe; 42-Second-effect salt foot; 43-Triple-effect heating chamber; 44-Triple-effect circulation pump; 45-Triple-effect lower circulation pipe; 46-Triple-effect upper circulation pipe; 47-Triple-effect salt foot. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are 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 device or element referred to 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.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0043] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0044] like Figure 1 As shown, a food-grade potassium chloride production device includes a steam system 30, a condensed water system 31, and a feeding unit, a hot melt purification unit, an evaporation crystallization unit, a thickening and dehydration unit, and a drying and packaging unit arranged in sequence;

[0045] The loading unit includes a crane 1 and a bag unpacker 2. The crane 1 lifts the ton bag of raw material potassium chloride, and the bag unpacker 2 unpacks the ton bag.

[0046] The hot melt purification unit includes a hot melt tank 3, a reagent tank, a clarification barrel 7, a membrane filter 10, a plate and frame filter press 11, a refined brine barrel 12 and a recovery system 32; the feed end of the hot melt tank 3 corresponds to the discharge end of the unpacking machine 2, receives the raw potassium chloride after unpacking, and the condensed water system 31 provides condensed water for dissolving the raw potassium chloride to the hot melt tank 3; the discharge end of the hot melt tank 3 is connected to the feed end of the clarification barrel 7 through the raw brine pump 4, and a stirring device is provided in the hot melt tank 3; the clear liquid discharge end of the clarification barrel 7 is connected to the feed end of the membrane filter 10 through the brine conversion pump 8, and the sludge discharge end of the clarification barrel 7 is connected to the feed end of the plate and frame filter press 11 through the sludge pump 9, and a stirring device is provided in the clarification barrel 7, the bottom of the inner cavity is an inclined bottom, and the clear liquid discharge end of the clarification barrel 7 is located at On the side with a high sloping bottom, the sludge discharge end of the clarification barrel 7 is located on the side with a low sloping bottom; the liquid outlet end of the membrane filter 10 and the liquid outlet end of the plate and frame filter press 11 are connected to the feed end of the refined brine barrel 12; the refined brine barrel 12 provides the purified and impurity-removed potassium chloride solution to the evaporation crystallization unit through the feed pump 14, and the refined brine barrel 12 is provided with an insulation pipe, the steam inlet of the insulation pipe is connected to the steam system 30, the steam system 30 provides insulation steam for the refined brine barrel 12, and the condensate outlet of the insulation pipe is connected to the recovery system 32, and the condensed water generated by the steam insulation is sent to the recovery system 32; the reagent tank includes a potassium hydroxide reagent tank 5 and a potassium carbonate reagent tank 6 for adding reagents to the hot melt tank 3, and a hydrochloric acid reagent tank 13 for adding reagents to the refined brine barrel 12;

[0047] The evaporation crystallization unit includes a first-effect evaporation crystallization system, a second-effect evaporation crystallization system, a third-effect evaporation crystallization system, a salt slurry barrel 18 and a mixed condensation system 29;

[0048] The single-effect evaporation crystallization system comprises a single-effect evaporation crystallization tank 15, a single-effect heating chamber 33, a single-effect circulation pump 34, a single-effect lower circulation pipe 35, a single-effect upper circulation pipe 36, and a single-effect salt foot 37; the single-effect salt foot 37 is arranged at the cone bottom of the single-effect evaporation crystallization tank 15; the discharge port of the single-effect evaporation crystallization tank 15 is connected to the feed port of the single-effect circulation pump 34 through the single-effect lower circulation pipe 35; the discharge port of the single-effect circulation pump 34 is connected to the feed port of the single-effect heating chamber 33, and the discharge port of the single-effect heating chamber 33 is connected to the feed port of the single-effect evaporation crystallization tank 15 through the single-effect upper circulation pipe 36;

[0049] The two-effect evaporation crystallization system comprises a two-effect evaporation crystallization tank 16, a two-effect heating chamber 38, a two-effect circulation pump 39, a two-effect lower circulation pipe 40, a two-effect upper circulation pipe 41, and a two-effect salt foot 42; the two-effect salt foot 42 is arranged at the cone bottom of the two-effect evaporation crystallization tank 16; the discharge port of the two-effect evaporation crystallization tank 16 is connected to the feed port of the two-effect circulation pump 39 through the two-effect lower circulation pipe 40; the discharge port of the two-effect circulation pump 39 is connected to the feed port of the two-effect heating chamber 38, and the discharge port of the two-effect heating chamber 38 is connected to the feed port of the two-effect evaporation crystallization tank 16 through the two-effect upper circulation pipe 41;

[0050] The triple-effect evaporation crystallization system comprises a triple-effect evaporation crystallization tank 17, a triple-effect heating chamber 43, a triple-effect circulation pump 44, a triple-effect lower circulation pipe 45, a triple-effect upper circulation pipe 46, and a triple-effect salt foot 47; the triple-effect salt foot 47 is arranged at the conical bottom of the triple-effect evaporation crystallization tank 17; the discharge port of the triple-effect evaporation crystallization tank 17 is connected to the feed port of the triple-effect circulation pump 44 through the triple-effect lower circulation pipe 45; the discharge port of the triple-effect circulation pump 44 is connected to the feed port of the triple-effect heating chamber 43, and the discharge port of the triple-effect heating chamber 43 is connected to the feed port of the triple-effect evaporation crystallization tank 17 through the triple-effect upper circulation pipe 46;

[0051] The outlet ends of the first-effect upper circulation pipe 36, the second-effect upper circulation pipe 41, and the third-effect upper circulation pipe 46 are all trumpet-shaped and extend into the interior of the corresponding evaporation crystallization tanks respectively; the bottoms of the first-effect salt foot 37, the second-effect salt foot 42, and the third-effect salt foot 47 are all provided with salt slurry outlets; the upper outer parts of the first-effect heating chamber 33, the second-effect heating chamber 38, and the third-effect heating chamber 43 are all provided with steam inlets; the upper parts of the first-effect lower circulation pipe 35, the second-effect lower circulation pipe 40, and the third-effect lower circulation pipe 45 are all provided with potassium chloride solution inlets; the tops of the first-effect evaporation crystallization tank 15, the second-effect evaporation crystallization tank 16, and the third-effect evaporation crystallization tank 17 are all provided with secondary steam outlets; the bottoms of the second-effect lower circulation pipe 40 and the third-effect lower circulation pipe 45 are all provided with slurry transfer inlets;

[0052] The steam system 30 is connected to the steam inlet of the first-effect heating chamber 33 to supply steam to the first-effect heating chamber 33, the secondary steam outlet of the first-effect evaporation crystallization tank 15 is connected to the steam inlet of the second-effect heating chamber 38, the secondary steam outlet of the second-effect evaporation crystallization tank 16 is connected to the steam inlet of the third-effect heating chamber 43, and the secondary steam outlet of the third-effect evaporation crystallization tank 17 is connected to the mixed condensation system 29;

[0053] The discharge end of the refined brine barrel 12 is connected to the potassium chloride solution inlet of the first effect lower circulation pipe 35, the potassium chloride solution inlet of the second effect lower circulation pipe 40, and the potassium chloride solution inlet of the third effect lower circulation pipe 45 respectively through the feed pump 14;

[0054] The salt slurry outlet of the first-effect salt foot 37 is connected to the slurry transfer port of the second-effect lower circulation pipe 40, the salt slurry outlet of the second-effect salt foot 42 is connected to the slurry transfer port of the third-effect lower circulation pipe 45, and the salt slurry outlet of the third-effect salt foot 47 is connected to the feed end of the salt slurry barrel 18; the slurry outlet end of the salt slurry barrel 18 is connected to the feed end of the thickening and dehydration unit through the transfer pump 19;

[0055] The thickening and dehydration unit includes a thickener 20 and a centrifuge 21; the inner cavity of the thickener 20 is provided with a stirring device, a weighing sensor device 28 is arranged under the outer leg, a mother liquor brine outlet is arranged on the top side, and a clean potassium chloride solution inlet is arranged on the bottom; the salt slurry feed end of the thickener 20 is connected to the slurry outlet end of the salt slurry barrel 18 through a transfer pump 19, the salt slurry outlet end on the bottom side of the thickener 20 is connected to the feed end of the centrifuge 21, the mother liquor brine outlet of the thickener 20 is connected to the recovery port of the salt slurry barrel 18, and the clean potassium chloride solution inlet of the thickener 20 is connected to the discharge end of the refined brine barrel 12; the wet potassium discharge end of the centrifuge 21 is connected to the feed end of the drying and packaging unit, and the mother liquor outlet of the centrifuge 21 is connected to the recovery port of the refined brine barrel 12;

[0056] The drying and packaging unit includes a vibrating feeder 22, a drying system 23, a vibrating screen 34, a belt conveyor 35, a finished product silo 36 and a packaging machine 27 which are connected in sequence; the feed end of the vibrating feeder 22 receives the wet potassium chloride provided by the centrifuge 21, the discharge end of the vibrating feeder 22 is connected to the feed end of the drying system 23, the discharge end of the drying system 23 is connected to the feed end of the vibrating screen 24, the discharge end of the vibrating screen 24 is connected to the feed end of the belt conveyor 25, the discharge end of the belt conveyor 25 is connected to the feed end of the finished product silo 26, and the discharge end of the finished product silo 26 is connected to the feed end of the packaging machine 27.

[0057] like Figure 2 As shown, the process of preparing food-grade potassium chloride by the production device of food-grade potassium chloride described in this embodiment is as follows:

[0058] S1. Purchase high-quality raw material potassium chloride (usually 62% potassium as raw material (in terms of K2O)) and put it into a hot melt tank, and add 90°C condensed water to prepare a saturated potassium chloride solution with a mass percentage concentration of 33%, and then successively add a prepared potassium hydroxide solution with a mass percentage concentration of 10% and a potassium carbonate solution with a mass percentage concentration of 15%;

[0059] S2. The saturated potassium chloride solution after heat dissolution is pumped into a clarification barrel by a raw brine pump, stirred and reacted for 4 hours in a clarification barrel with a bottom inclination angle of 2°, and then the stirring was stopped and the solution was allowed to stand for 2 hours;

[0060] S3. The clarified saturated potassium chloride solution in the upper part of the clarification barrel enters the membrane filter through the brine transfer pump for filtration and impurity removal again before entering the refined brine barrel; after the two batches of hot-dissolved saturated potassium chloride solutions are deposited in the clarification barrel, the sludge at the bottom is regularly discharged to the plate and frame filter press for treatment through the sludge pump, and the filtrate of the plate and frame filter press enters the refined brine barrel;

[0061] S4. A half pipe with a diameter of 50mm and a spacing of 500mm is set on the outside of the refined brine barrel as an insulation pipe, and steam is introduced for insulation. The amount of steam introduced is to control the temperature of the potassium chloride solution in the refined brine barrel to 85°C, and the generated condensed water is used in the recovery system for comprehensive utilization; hydrochloric acid is added dropwise to the saturated potassium chloride solution in the refined brine barrel to adjust the pH value, and then divided into three streams of materials and simultaneously fed to the first-effect evaporation crystallization system, the second-effect evaporation crystallization system, and the third-effect evaporation crystallization system;

[0062] S5, the saturated potassium chloride solution first enters the lower circulation pipe of each effect evaporation crystallization system, and then is pumped to each effect heating chamber by each effect circulation pump to heat the material, and enters each effect evaporation crystallization tank in the form of axial feeding through each effect upper circulation pipe to evaporate and precipitate potassium chloride crystals; each effect circulation pump adopts frequency conversion regulation, and its speed is controlled to be 800 rpm; the total effective volume of the first, second and third effect evaporation crystallization tanks is 5 times the hourly feed amount of potassium chloride solution in the refined brine barrel;

[0063] When the salt slurry crystallized in the first-effect evaporation crystallization tank reaches 10%, it is transferred to the second-effect evaporation crystallization system as a seed for cyclic crystallization. When the salt slurry crystallized in the second-effect evaporation crystallization tank reaches 25%, it is transferred to the third-effect evaporation crystallization system as a seed for cyclic crystallization; wherein the first-effect heating chamber is heated by steam from the same source as the refined brine barrel, the temperature of the steam entering the first-effect heating chamber is controlled at 120°C, the secondary steam generated by the first-effect evaporation crystallization tank enters the second-effect heating chamber for heating, the steam temperature of the second-effect heating chamber is controlled at 90°C, the secondary steam generated by the second-effect evaporation crystallization tank enters the third-effect heating chamber for heating, the steam temperature of the third-effect heating chamber is controlled at 60°C, and the secondary steam generated by the third-effect evaporation crystallization tank enters the mixed condensation system for condensation treatment;

[0064] S6. After the slurry crystallized by the triple-effect evaporation crystallization system is discharged into the salt slurry barrel, it is sent to the thickener by the transfer pump, and the stirring speed is controlled to be 2 rpm. The thickened potassium chloride slurry enters the centrifuge for solid-liquid separation; the saturated potassium chloride solution from the refined brine barrel is passed into the thickener for washing, and the volume of the potassium chloride solution passed is 0.01 times the total effective volume of the slurry in the thickener; the overflow liquid generated by the thickener is returned to the salt slurry barrel; the mother liquor after dehydration in the centrifuge is returned to the refined brine barrel for recycling;

[0065] S7. Dry, screen and package the wet potassium chloride after centrifugal dehydration to obtain a food-grade potassium chloride product.

[0066] After testing: the process method consumes 0.79 tons of steam for each ton of potassium chloride product; the crystal particle size of the potassium chloride product is roughly consistent with that of edible salt, and the particle distribution meets D10: 0.2mm, D90: 0.5mm, with 0.4-0.45mm being the majority. When used as a compound raw material for low-sodium salt, it can be evenly mixed with edible salt and is not easy to stratify. The product quality is stable, the entire device is not easy to scale and clog, and the device runs stably and efficiently.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A production device for food-grade potassium chloride, characterized in that: It includes a steam system, a condensed water system, and a feeding unit, a hot melt purification unit, an evaporation crystallization unit, a thickening and dehydration unit, and a drying and packaging unit arranged in sequence; The discharge end of the feeding unit is connected to the feed end of the hot melt purification unit; The hot melt purification unit is used to thermally dissolve the raw potassium chloride into a saturated potassium chloride solution and purify and remove impurities. The discharge end of the hot melt purification unit is connected to the feed end of the evaporation crystallization unit; The evaporation and crystallization unit is used to evaporate and crystallize the purified and impurity-removed potassium chloride solution into potassium chloride slurry, and the discharge end of the evaporation and crystallization unit is connected to the feed end of the thickening and dehydration unit; The thickening and dehydration unit is used to thicken and dehydrate the potassium chloride slurry, and the discharge end of the thickening and dehydration unit is connected to the feed end of the drying and packaging unit; The drying and packaging unit is used to dry and package the thickened and dehydrated potassium chloride; The steam system is used to provide steam to the hot melt purification unit and the evaporation crystallization unit; The condensed water system is used to provide condensed water to the hot melt purification unit.

2. The production device of food grade potassium chloride according to claim 1, characterized in that: The loading unit includes a crane and a bag unpacker. The crane lifts the ton bag of raw potassium chloride, and the bag unpacker opens the ton bag, and the raw potassium chloride falls into the feeding end of the hot melt purification unit.

3. The production device of food grade potassium chloride according to claim 1, characterized in that: The hot melt purification unit includes a hot melt tank, a reagent tank, a clarification tank, a filter, a filter press, and a brine tank; The feed end of the hot melt tank corresponds to the discharge end of the loading unit, and the condensed water system provides condensed water for dissolving raw potassium chloride to the hot melt tank; the discharge end of the hot melt tank is connected to the feed end of the clarification barrel through a raw brine pump; the clear liquid discharge end of the clarification barrel is connected to the feed end of the filter through a brine conversion pump, and the sludge discharge end of the clarification barrel is connected to the feed end of the filter press through a sludge pump; the liquid outlet end of the filter and the liquid outlet end of the filter press are connected to the feed end of the refined brine barrel; the refined brine barrel provides the evaporation and crystallization unit with purified and impurity-free potassium chloride solution through a feed pump; the reagent tank includes a potassium hydroxide reagent tank and a potassium carbonate reagent tank for adding reagents into the hot melt tank, and a hydrochloric acid reagent tank for adding reagents into the refined brine barrel.

4. The production device of food grade potassium chloride according to claim 3, characterized in that: The hot melt purification unit also includes a recovery system; the refined brine barrel is provided with an insulation pipe, the steam inlet of the insulation pipe is connected to the steam system, and the condensate outlet of the insulation pipe is connected to the recovery system.

5. The production device of food grade potassium chloride according to claim 3, characterized in that: The filter is a membrane filter; the filter press is a plate and frame filter press; a stirring device is provided in the clarification barrel, the bottom of the inner cavity is an inclined bottom, the clear liquid discharge end of the clarification barrel is located on the side with a higher inclined bottom, and the sludge discharge end of the clarification barrel is located on the side with a lower inclined bottom.

6. The production device of food-grade potassium chloride according to any one of claims 3 to 5, characterized in that: The evaporation crystallization unit comprises a first-effect evaporation crystallization system, a second-effect evaporation crystallization system, a third-effect evaporation crystallization system, a salt slurry barrel and a mixed condensation system; The single-effect evaporation crystallization system comprises a single-effect evaporation crystallization tank, a single-effect heating chamber, a single-effect circulation pump, a single-effect lower circulation pipe, a single-effect upper circulation pipe, and a single-effect salt foot; the single-effect salt foot is arranged at the conical bottom of the single-effect evaporation crystallization tank; the discharge port of the single-effect evaporation crystallization tank is connected to the feed port of the single-effect circulation pump through the single-effect lower circulation pipe; the discharge port of the single-effect circulation pump is connected to the feed port of the single-effect heating chamber, and the discharge port of the single-effect heating chamber is connected to the feed port of the single-effect evaporation crystallization tank through the single-effect upper circulation pipe; The two-effect evaporation crystallization system comprises a two-effect evaporation crystallization tank, a two-effect heating chamber, a two-effect circulation pump, a two-effect lower circulation pipe, a two-effect upper circulation pipe, and a two-effect salt foot; the two-effect salt foot is arranged at the conical bottom of the two-effect evaporation crystallization tank; the discharge port of the two-effect evaporation crystallization tank is connected to the feed port of the two-effect circulation pump through the two-effect lower circulation pipe; the discharge port of the two-effect circulation pump is connected to the feed port of the two-effect heating chamber, and the discharge port of the two-effect heating chamber is connected to the feed port of the two-effect evaporation crystallization tank through the two-effect upper circulation pipe; The triple-effect evaporation crystallization system comprises a triple-effect evaporation crystallization tank, a triple-effect heating chamber, a triple-effect circulation pump, a triple-effect lower circulation pipe, a triple-effect upper circulation pipe, and a triple-effect salt foot; the triple-effect salt foot is arranged at the conical bottom of the triple-effect evaporation crystallization tank; the discharge port of the triple-effect evaporation crystallization tank is connected to the feed port of the triple-effect circulation pump through the triple-effect lower circulation pipe; the discharge port of the triple-effect circulation pump is connected to the feed port of the triple-effect heating chamber, and the discharge port of the triple-effect heating chamber is connected to the feed port of the triple-effect evaporation crystallization tank through the triple-effect upper circulation pipe; The steam system is connected to the steam inlet of the first-effect heating chamber, the secondary steam outlet of the first-effect evaporation crystallization tank is connected to the steam inlet of the second-effect heating chamber, the secondary steam outlet of the second-effect evaporation crystallization tank is connected to the steam inlet of the third-effect heating chamber, and the secondary steam outlet of the third-effect evaporation crystallization tank is connected to the mixed condensation system; The discharge end of the refined brine barrel is connected to the potassium chloride solution inlet of the first effect lower circulation pipe, the potassium chloride solution inlet of the second effect lower circulation pipe, and the potassium chloride solution inlet of the third effect lower circulation pipe respectively through a feed pump; The salt slurry outlet of the first-effect salt foot is connected to the slurry transfer inlet of the second-effect lower circulation pipe, the salt slurry outlet of the second-effect salt foot is connected to the slurry transfer inlet of the third-effect lower circulation pipe, the salt slurry outlet of the third-effect salt foot is connected to the feed end of the salt slurry barrel, and the slurry outlet end of the salt slurry barrel is connected to the feed end of the thickening and dehydration unit through a transfer pump.

7. The production device of food grade potassium chloride according to claim 6, characterized in that: The outlet ends of the first-effect upper circulation pipe, the second-effect upper circulation pipe and the third-effect upper circulation pipe are all trumpet-shaped and extend into the interior of the corresponding evaporation crystallization tanks respectively.

8. The production device of food grade potassium chloride according to claim 7, characterized in that: The thickening and dehydration unit includes a thickener and a centrifuge; the salt slurry feed end of the thickener is connected to the slurry outlet end of the salt slurry barrel through a transfer pump, the salt slurry outlet end on the bottom side of the thickener is connected to the feed end of the centrifuge, the wet potassium discharge end of the centrifuge is connected to the feed end of the drying and packaging unit, and the mother liquor outlet of the centrifuge is connected to the recovery port of the refined brine barrel.

9. The production device of food grade potassium chloride according to claim 8, characterized in that: The inner cavity of the thickener is provided with a stirring device, a mother liquor brine outlet is provided on the top side, and a clean potassium chloride solution inlet is provided at the bottom; the mother liquor brine outlet of the thickener is connected to the recovery port of the salt slurry barrel; the clean potassium chloride solution inlet of the thickener is connected to the discharge end of the refined brine barrel.

10. The production device of food-grade potassium chloride according to claim 1, characterized in that: The drying and packaging unit comprises a vibrating feeder, a drying system, a vibrating screen, a belt conveyor, a finished product silo and a packaging machine which are connected in sequence; the feeding end of the vibrating feeder receives the thickened and dehydrated wet potassium chloride provided by the thickening and dehydration unit.

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