Resource comprehensive utilization system for removing nitrogen from salt lake brine by using ammonia evaporation calcium liquid

Abstract

This invention discloses a comprehensive resource utilization system for denitrification of salt lake brine using ammonia-calcium stripping solution. The system includes a reaction device, a clarification device, a filter press, an ammonia-calcium stripping solution storage device, and a nitrate-rich brine storage device. The outlets of both the ammonia-calcium stripping solution storage device and the nitrate-rich brine storage device are connected to the inlet of the reaction device via pipelines. The outlet of the reaction device is connected to the inlet of the clarification device, and the purified brine outlet of the clarification device is connected to the inlet of the crude brine tank of the salt lake and / or salt production system. The calcium sulfate turbidity outlet of the clarification device is connected to the inlet of the filter press. This invention enables the recovery and utilization of salt and water resources from the ammonia-calcium stripping solution, while simultaneously improving the quality of the salt lake brine and achieving sustainable utilization of salt lake resources.

Description

Technical Field

[0001] This utility model relates to a resource comprehensive utilization system, and in particular to a resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate. Background Technology

[0002] my country is a major country with salt lake resources. In recent years, due to factors such as continuous drought and highway construction, the brine water level in many lake areas has been declining year by year. If this continues, it will affect the production of recycled salt and sun-dried salt. Reasonable and effective replenishment of salt lakes is imperative.

[0003] Using the ammonia-soda process for alkali production, approximately 3.6 million cubic meters of ammonia-soaked calcium chloride solution are discharged annually in the Jilantai area of ​​Inner Mongolia alone. Each cubic meter of calcium chloride solution contains 920-950 kg of water, 125-135 kg of calcium chloride, and 55-65 kg of sodium chloride. Currently, the treatment method for this ammonia-soaked calcium chloride solution involves constructing large-scale calcium chloride ponds, discharging the solution into these ponds for natural evaporation through sun exposure, recovering the precipitated sodium chloride crystals, and using a nearby calcium chloride plant to produce calcium chloride products from the concentrated calcium chloride solution. However, a significant amount of water cannot be recovered.

[0004] In addition, the rock salt deposit has been mined for many years. The mining process only extracts rock salt from the deposit, while associated minerals such as sodium sulfate and magnesium sulfate have not been mined. As a result, calcium, magnesium and sulfate ions are relatively enriched in the brine, the quality of the intercrystalline brine has declined year by year, and the sulfate content in the crystallized regenerated salt exceeds the standard, which has seriously affected the product quality. Utility Model Content

[0005] The purpose of this invention is to provide a comprehensive resource utilization system for denitrification of salt lake brine using ammonia-calcium stripping solution. This system can recover and utilize the salt and water resources in the ammonia-calcium stripping solution, while improving the quality of salt lake brine and realizing the sustainable utilization of salt lake resources.

[0006] This utility model is implemented by the following technical solution: a resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium stripping solution, comprising a reaction device, a clarification device, a filter press, an ammonia-calcium stripping solution storage device, and a nitrate-rich brine storage device; the outlets of the ammonia-calcium stripping solution storage device and the nitrate-rich brine storage device are both connected to the inlet of the reaction device via pipelines; the outlet of the reaction device is connected to the inlet of the clarification device, and the purified brine outlet of the clarification device is connected to the inlet of the crude brine tank of the salt lake and / or salt production system; the calcium sulfate turbidity outlet of the clarification device is connected to the inlet of the filter press.

[0007] Specifically, the clarification device includes at least two clarification pools, with a sand filter dam between two adjacent clarification pools and a height difference between them; the outlet of the reaction device is connected to the inlet of the highest clarification pool; the lowest clarification pool is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system; and the calcium sulfate turbid liquid outlet of each clarification pool is connected to the inlet of the filter press device.

[0008] Specifically, the sand filter dam includes two side slope masonry layers and a middle sand filter layer. The side slope masonry layers are constructed by staggered joints of several woven bags filled with coarse sand. The sand filter layer is formed by filling the space between the two side slope masonry layers with fine sand.

[0009] Specifically, the bottom and walls of the clarification tank are covered with polyvinyl chloride geomembrane, and adjacent polyvinyl chloride geomembranes are laid in a staggered manner and welded together; several clay bricks are placed at intervals above the polyvinyl chloride geomembrane laid on the bottom of the tank.

[0010] Specifically, a clear liquid tank is provided between the lowest clarification tank and the salt lake, and the lowest clarification tank and the clear liquid tank are connected by a pipeline; the clear liquid tank is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system.

[0011] Specifically, the reaction device is a reaction tank or a reactor.

[0012] Specifically, the filter press is a desulfurized gypsum belt filter or a vacuum belt filter.

[0013] Specifically, the ammonia-diluted calcium solution storage device is a calcium solution buffer tank.

[0014] Specifically, the resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate also includes a freezing tank, the salt lake is connected to the inlet of the freezing tank, the nitrate-rich brine outlet of the freezing tank is connected to the inlet of the nitrate-rich brine storage device, and the nitrate-poor brine overflow outlet of the freezing tank is connected to the inlet of the coarse brine tank of the salt production system through an overflow pipe.

[0015] Advantages of this utility model:

[0016] (1) This utility model involves adding salt lake nitrate-rich brine and ammonia-calcium stripping solution to a reaction device to react the SO4 in the salt lake nitrate-rich brine. 2- With the calcium in the ammonia-calcium solution 2+ The calcium sulfate produced is then filtered and used to fill the mined-out areas of the salt lake; the calcium sulfate solution is used to remove calcium. 2+ The resulting clear liquid can be used for salt lake replenishment, enabling the recycling of salt and water resources from the ammonia-calcium distillate, while also improving the quality of the salt lake brine and achieving sustainable utilization of salt lake resources.

[0017] (2) Utilize natural conditions to carry out calcium solution recovery and salt lake brine purification projects. Based on science and environmental protection, gradually reduce the sulfate impurity content in the salt lake water, improve the quality of raw salt crystallization, and effectively reduce the cost of salt and alkali products as well as the consumption of medicines. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of a comprehensive resource utilization system for denitrification of salt lake brine using ammonia-calcium distillate.

[0020] Figure 2 This is a schematic diagram of the cross-sectional structure of a sand filter dam.

[0021] 1. Reaction device; 2. Clarification device; 2.1. Clarification tank; 2.2. Sand filter dam; 2.3. Slope masonry layer; 2.4. Sand filter layer; 3. Filter press device; 4. Nitrate-rich brine storage device; 5. Clear liquid tank; 6. Frozen nitrate tank; 7. Ammonia-calcium solution storage device. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] A comprehensive resource utilization system for denitrification of salt lake brine using ammonia-calcium distillate, such as... Figure 1As shown, it includes a reaction device 1, a clarification device 2, a filter press 3, a calcium ammonia stripping solution storage device 7, and a nitrate-rich brine storage device 4; the outlets of the calcium ammonia stripping solution storage device 7 and the nitrate-rich brine storage device 4 are both connected to the inlet of the reaction device 1 via pipelines; the outlet of the reaction device 1 is connected to the inlet of the clarification device 2, and the purified brine outlet of the clarification device 2 is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system; the calcium sulfate turbid liquid outlet of the clarification device 2 is connected to the inlet of the filter press 3. The ammonia-calcium stripping solution in storage device 7 and the nitrate-rich brine in storage device 4 are added to reaction device 1. This allows SO42- in the nitrate-rich brine of the salt lake to combine with Ca2+ in the ammonia-calcium stripping solution to form calcium sulfate precipitate. After the reaction, the reaction solution is sent to clarification device 2. After multi-stage filtration in clarification device 2, calcium sulfate is removed. The remaining clarified brine meets the standards for high-quality intercrystalline brine and is either discharged into the waterway via the brine discharge ditch, or pumped to dynamically replenish the salt lake; or pumped into the crude brine tank of the salt production system for salt production. The calcium sulfate is dehydrated by pressure filtration device 3 and then used for backfilling and storage in the mined-out area.

[0024] In one specific embodiment, the clarification device 2 includes at least two clarification pools 2.1. The number of clarification pools 2.1 is determined based on the final clarified brine indicators obtained after filtration reaching the high-quality intercrystalline brine indicators. A sand filter dam 2.2 is provided between two adjacent clarification pools 2.1, and there is a height difference between the two adjacent clarification pools 2.1. This allows the brine in the clarification pools 2.1 to utilize the hydraulic gradient difference, flowing from the higher clarification pool 2.1 through the sand filter dam 2.2 and into the lower clarification pool 2.1, achieving the filtration purpose. The outlet of the reaction device 1 is connected to the inlet of the highest clarification pool 2.1; the lowest clarification pool 2.1 is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system; the calcium sulfate turbid liquid outlet of each clarification pool 2.1 is connected to the inlet of the filter press device 3. The clarification pools 2.1 can be constructed using the mined-out areas near the salt lake, reducing construction costs, making reasonable use of land resources, and facilitating the subsequent filling and storage of calcium sulfate in the mined-out areas.

[0025] In one specific implementation, such as Figure 2 As shown, the sand filter dam 2.2 includes two side slope masonry layers 2.3 and a middle sand filter layer 2.4. The slope masonry layers 2.3 are constructed by staggered joints of several woven bags filled with coarse sand; the sand filter layer 2.4 is formed by filling the spaces between the two side slope masonry layers 2.3 with fine sand. The slope masonry layers 2.3 ensure that brine can pass through and achieve primary filtration while reinforcing the dam body, while the sand filter layer 2.4 is used to filter calcium sulfate precipitates. The sand filter dam 2.2 is 1.5 meters wide at the top, 2.5 meters wide at the bottom, and 1.2 meters high, while the width of the slope masonry layers 2.3 is less than 0.5 meters.

[0026] In one specific embodiment, the bottom and walls of the clarification tank 2.1 are both covered with two layers of polyvinyl chloride geomembrane for seepage prevention. The thickness of a single layer of membrane is 0.5 mm. Adjacent polyvinyl chloride geomembranes are laid in a staggered manner and welded together. Several clay bricks are placed at intervals above the polyvinyl chloride geomembrane laid on the bottom of the tank for pressing the membrane.

[0027] In one specific embodiment, a clear liquid tank 5 is provided between the lowest clarification tank 2.1 and the salt lake to store clarified brine that meets the standards for high-quality intercrystalline brine. The lowest clarification tank 2.1 and the clear liquid tank 5 are connected by a pipeline; the clear liquid tank 5 is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system.

[0028] In one specific embodiment, the reaction device 1 can be a reaction tank or a reactor. The total volume of the reaction tank is greater than 600 m³, ensuring that the residence time of the reaction liquid is greater than 40 min.

[0029] In one specific embodiment, the filter press 3 is a desulfurized gypsum belt filter or a vacuum belt filter.

[0030] In one specific embodiment, the ammonia-free calcium solution storage device 7 is a calcium solution buffer tank.

[0031] In one specific embodiment, it also includes a freezing tank 6, with the salt lake connected to the inlet of the freezing tank 6. The outlet of the rich brine in the freezing tank 6 is connected to the inlet of the rich brine storage device 4. The overflow outlet of the lean brine in the freezing tank 6 is connected to the inlet of the crude brine tank of the salt-making system via an overflow pipe. In winter, the rich brine in the salt lake is first pumped into the freezing tank 6. Taking advantage of the low winter temperature, sodium sulfate crystallizes and precipitates. The lean brine after sodium sulfate precipitation flows out through the overflow outlet and is pumped to the crude brine tank of the salt-making system for salt production. The remaining concentrated sodium sulfate is pumped to the rich brine storage device 4 to react with the ammonia-calcium stripping solution, removing calcium ions from the ammonia-calcium stripping solution and recovering the water from the ammonia-calcium stripping solution for salt lake replenishment. In other seasons, the rich brine in the salt lake is directly pumped into the rich brine storage device 4 for purifying and recovering the ammonia-calcium stripping solution.

[0032] By utilizing sodium sulfate, an impurity in the salt lake brine, to remove calcium ions from the ammonia-calcium stripping solution, the brine is purified while being recycled. The purified brine is then reused. By processing sodium sulfate and ammonia-calcium stripping solution at a 1:1 ratio, the sodium sulfate produced can process approximately 95,000 m³ of ammonia-calcium stripping solution annually. This significantly reduces the discharge of ammonia-calcium stripping solution, alleviates pressure on the calcium solution storage, extends the operating cycle of the calcium solution pool, and meets the environmental protection requirements of green mining.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A comprehensive resource utilization system for denitrification of salt lake brine using ammonia-calcium distillate, characterized in that, It includes a reaction device, a clarification device, a filter press, a calcium ammonia stripping solution storage device, and a nitrate-rich brine storage device; the outlets of the calcium ammonia stripping solution storage device and the nitrate-rich brine storage device are both connected to the inlet of the reaction device via pipelines; the outlet of the reaction device is connected to the inlet of the clarification device, the purified brine outlet of the clarification device is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system; the calcium sulfate turbidity outlet of the clarification device is connected to the inlet of the filter press.

2. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 1, characterized in that, The clarification device includes at least two clarification tanks, with a sand filter dam between two adjacent clarification tanks and a height difference between them; the outlet of the reaction device is connected to the inlet of the highest clarification tank; the lowest clarification tank is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system; the calcium sulfate turbid liquid outlet of each clarification tank is connected to the inlet of the filter press device.

3. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 2, characterized in that, The sand filter dam includes two side slope masonry layers and a middle sand filter layer. The side slope masonry layers are constructed by staggered joints of several woven bags filled with coarse sand. The sand filter layer is formed by filling the space between the two side slope masonry layers with fine sand.

4. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 2, characterized in that, The bottom and walls of the clarification tank are covered with polyvinyl chloride geomembrane. Adjacent polyvinyl chloride geomembranes are laid in a staggered manner and welded together. Several clay bricks are placed at intervals above the polyvinyl chloride geomembrane laid on the bottom of the tank.

5. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to any one of claims 2-4, characterized in that, A clear liquid tank is provided between the lowest clarification tank and the salt lake, and the lowest clarification tank and the clear liquid tank are connected by a pipeline; the clear liquid tank is connected to the inlet of the crude brine tank of the salt lake and / or the salt production system.

6. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 1, characterized in that, The reaction device is a reaction tank or reactor.

7. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 1, characterized in that, The filter press is a desulfurized gypsum belt filter or a vacuum belt filter.

8. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 1, characterized in that, The storage device for the ammonia-diluted calcium solution is a calcium solution buffer tank.

9. The resource comprehensive utilization system for denitrification of salt lake brine using ammonia-calcium distillate solution according to claim 1, characterized in that, It also includes a frozen nitrate pool, the salt lake is connected to the inlet of the frozen nitrate pool, the nitrate-rich brine outlet of the frozen nitrate pool is connected to the inlet of the nitrate-rich brine storage device; the nitrate-poor brine overflow outlet of the frozen nitrate pool is connected to the inlet of the coarse brine tank of the salt production system through an overflow pipe.

Images