Production system for co-production of phosphorus pentoxide and hot-process phosphoric acid

Abstract

The utility model discloses a production system for co-production of phosphorus pentoxide and hot-process phosphoric acid, and belongs to the technical field of phosphorus chemical industry. The system comprises a phosphoric acid production device and a phosphorus pentoxide production device, the phosphoric acid production device comprises a yellow phosphorus storage tank, a settling tank, a first phosphorus combustion tower, a hydration structure and a first tail gas treatment structure, and the phosphorus pentoxide production device comprises a rotary vibration sieve, a second phosphorus combustion tower, a cooling tower, a settling tower and a second tail gas treatment structure. The first phosphorus combustion tower and the second phosphorus combustion tower are both provided with steam pockets, heaters are arranged in the yellow phosphorus storage tank and the settling tank, the hydration structure comprises two stages of hydration mechanisms, and the hydration mechanism comprises a hydration tower, a heat exchanger and a circulating tank; a feeding hole of the rotary vibration sieve is connected with a discharging hole in the bottom of the cooling tower, a coarse material outlet of the rotary vibration sieve is connected with a circulating groove of the primary hydration mechanism through a conveying structure, and a wastewater outlet of the second tail gas treatment structure is connected with a circulating groove of the secondary hydration mechanism; a feeding hole of the second phosphorus burning tower is connected with the yellow phosphorus storage tank; and the steam pocket is connected with the heater.

Description

Technical Field

[0001] The utility model belongs to the technical field of phosphorus chemical industry, and particularly relates to a production system for phosphorus pentoxide co-producing thermal phosphoric acid. Background Art

[0002] Both thermal phosphoric acid and phosphorus pentoxide can be obtained by burning yellow phosphorus. The preparation processes of thermal phosphoric acid and phosphorus pentoxide can be found in the following patents:

[0003] The patent with application number CN202120468720.6 discloses a compact phosphorus pentoxide production system, including a cooling water supply device, an exhaust gas treatment device, and a phosphorus burning tower, a cooling device, a settling device and a storage bin connected in sequence, wherein the cooling device includes a plurality of cooling towers connected in series in sequence, and the settling device includes a plurality of settling towers connected in series in sequence and a conveying structure for delivering the phosphorus pentoxide output from the settling tower to the storage bin, and a cooling jacket is provided on the cooling tower, and the cooling jacket is connected to the cooling water supply device through a pipeline; the system also includes a four-layer platform, and the phosphorus burning tower, the cooling device and the settling device are respectively arranged at the front, middle and rear of the four-layer platform, and a plurality of The cooling towers are arranged side by side on the left and right, the phosphorus burning tower is located in front of the first cooling tower, and multiple sedimentation towers are distributed in multiple columns side by side on the left and right, each column is composed of at least two sedimentation towers arranged side by side front and back, and the storage bin is located at the rear and lower side of the sedimentation device; the phosphorus burning tower and the cooling tower are arranged on the bottom to the third floor of the four-story platform, the sedimentation tower is arranged on the first and second floors of the four-story platform, the storage bin is arranged on the bottom floor of the four-story platform, the cooling water supply device is arranged on the third floor of the four-story platform, the conveying structure is arranged on the first floor of the four-story platform and its output end is to the bottom floor of the four-story platform, and the exhaust gas treatment device is connected to the last sedimentation tower through a pipeline and is arranged on the fourth floor of the four-story platform.

[0004] For example, the patent with application number CN201420317868.X discloses a polyphosphoric acid production system, including a refined molten phosphorus tank, a precipitated molten phosphorus tank, a combustion tower, a primary hydration structure, a secondary hydration structure, a dearsenicization reactor, a sedimentation tank, a plate and frame filter, a desorption reactor, a filter and a finished product storage tank connected in sequence by pipelines, the flue gas outlet of the secondary hydration structure is connected to a waste gas treatment system, the primary hydration structure and the secondary hydration structure are both self-circulating structures composed of pipelines, a hydration tower, a shell-and-tube heat exchanger, a circulation pump and a circulation pool, the circulation pool is provided with a detection port, and the circulation pump is electrically connected to an electric control box. That is, the existing phosphoric acid production system includes a first hydration structure, a second hydration structure and a circulating water supply structure, etc. The first hydration structure includes a first heat exchanger, a first hydration tower and a first circulation pool connected end to end, and the second hydration structure includes a second heat exchanger, a second hydration tower and a second circulation pool connected end to end. The exhaust port of the first hydration tower is connected to the air inlet of the second hydration tower through a pipeline. The first hydration tower and the second hydration tower are provided with cooling jackets outside, and the cooling jackets are connected to the circulating water supply structure through pipelines.

[0005] The applicant found the following problems when preparing phosphorus pentoxide:

[0006] (1) Phosphorus pentoxide is easy to adhere to the inner wall of the cooling tower. The vibration structure (such as air hammer, etc.) on the cooling tower shakes the phosphorus pentoxide on the inner wall off, resulting in a small amount of agglomerates in the phosphorus pentoxide output from the cooling tower. A rotary vibrating screen is needed to separate the agglomerates (customers usually require powdered phosphorus pentoxide, which is more active). Although the amount of separated phosphorus pentoxide is small, it is difficult to handle;

[0007] (2) The tail gas treatment process will produce wastewater, usually dilute acid, which needs to be treated. Summary of the invention

[0008] In order to solve the above problems, the embodiment of the utility model provides a production system of phosphorus pentoxide co-production of thermal phosphoric acid, in which the wastewater and phosphorus pentoxide agglomerates generated by the phosphorus pentoxide production device are sent to the phosphoric acid production device for utilization, no wastewater is generated, and the utilization rate of phosphorus is high. The technical solution is as follows:

[0009] The utility model provides a production system of phosphorus pentoxide co-production of thermal phosphoric acid, the system comprising a phosphoric acid production device and a phosphorus pentoxide production device, the phosphoric acid production device comprising a yellow phosphorus storage tank, a settling tank, a first phosphorus burning tower, a hydration structure and a first tail gas treatment structure connected in sequence, the phosphorus pentoxide production device comprising a second phosphorus burning tower, a cooling tower, a settling tank and a second tail gas treatment structure connected in sequence, the first phosphorus burning tower and the second phosphorus burning tower are both provided with a steam drum, the yellow phosphorus storage tank and the settling tank are both provided with a heater, the hydration structure comprises a two-stage hydration mechanism connected in series, the hydration mechanism comprises a hydration tower, a heat exchanger and a circulation tank connected end to end; it is characterized in that the phosphorus pentoxide production device also comprises a rotary vibrating screen, the feed inlet of the rotary vibrating screen is connected to the discharge port at the bottom of the cooling tower and the coarse material outlet thereof is connected to the circulation tank of the primary hydration mechanism through a conveying structure, the wastewater outlet of the second tail gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline; the feed inlet of the second phosphorus burning tower is connected to the yellow phosphorus storage tank through a pipeline, and the steam drum is connected to the heater through a pipeline.

[0010] Among them, the mesh aperture of the rotary vibrating screen in the embodiment of the utility model is 2.0-3.5mm.

[0011] Among them, the second exhaust gas treatment structure in the embodiment of the utility model includes a cyclone separator, a packed spray tower, a first cyclone spray tower, a second cyclone spray tower, a fiber dust collector and a fan which are connected in sequence through pipelines. The air inlet of the cyclone separator is connected to the air outlet of the sedimentation tower through a pipeline, and the wastewater outlets of the cyclone separator, the packed spray tower, the first cyclone spray tower, the second cyclone spray tower and the fiber dust collector are all connected to the wastewater main pipe, and the wastewater main pipe is connected to the circulation tank of the secondary hydration mechanism.

[0012] Furthermore, the phosphoric acid production device in the embodiment of the utility model also includes a first trough, and the phosphorus pentoxide production device also includes a second trough, the first trough is arranged next to the first phosphorus burning tower and is provided with a heater therein, the second trough is arranged next to the second phosphorus burning tower and is provided with a heater therein, and the first trough and the second trough are both closed troughs; the discharge port of the first trough is connected to the feed port of the first phosphorus burning tower through a pipeline, which is lower than the sedimentation tank, and its feed port is connected to the sedimentation tank through a pipeline; the discharge port of the second trough is connected to the feed port of the second phosphorus burning tower through a pipeline, and its feed port is connected to the yellow phosphorus storage tank through a pipeline.

[0013] Furthermore, the circulation tank of the secondary hydration mechanism in the embodiment of the utility model is connected to the circulation tank of the primary hydration mechanism through a pipeline, and the wastewater outlet of the first tail gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline.

[0014] Furthermore, the phosphorus pentoxide production device in the embodiment of the utility model also includes a spiral conveying structure, a coarse material silo, a powder material silo and a packaging structure at the bottom of the powder material silo, the spiral conveying structure is arranged between the discharge port of the cooling tower and the feed port of the rotary vibrating screen, the rotary vibrating screen is higher than the coarse material silo and the powder material silo, the coarse material outlet and the fine material outlet of the rotary vibrating screen are respectively connected to the top of the coarse material silo and the powder material silo through chutes, and the discharge port at the bottom of the coarse material silo is connected to the circulation groove of the primary hydration mechanism through the conveying structure.

[0015] Furthermore, the production system of phosphorus pentoxide co-production of thermal phosphoric acid in the embodiment of the utility model also includes a cooling water supply device, and the first phosphorus burning tower, the second phosphorus burning tower, the cooling tower, the powder silo and the hydration tower are all provided with cooling jackets, and the hot water outlets of the cooling jackets of the first phosphorus burning tower and the second phosphorus burning tower are connected to the corresponding steam drums through pipelines, and the cooling water supply device is connected to the cooling jackets and the heat exchanger through pipelines.

[0016] Furthermore, the production system of phosphorus pentoxide co-production of thermal phosphoric acid in the embodiment of the utility model also includes a phosphorus burning tower air supply device and a phosphorus burning gun air supply device, the phosphorus burning tower air supply device is connected to the air inlet of the first phosphorus burning tower and the second phosphorus burning tower through a pipeline, and the phosphorus burning gun air supply device is connected to the compressed air inlet of the spray gun on the first phosphorus burning tower and the second phosphorus burning tower through a pipeline.

[0017] The beneficial effects of the technical solution provided by the embodiment of the utility model are:

[0018] (1) The wastewater and phosphorus pentoxide agglomerates generated by the phosphorus pentoxide production device are sent to the phosphoric acid production device for utilization, no wastewater is generated, and the utilization rate of phosphorus is high.

[0019] (2) Sharing the yellow phosphorus storage tank, cooling water supply device, phosphorus burning tower gas supply device and phosphorus burning gun gas supply device can reduce costs.

[0020] (3) According to the production characteristics, yellow phosphorus is precipitated to separate mud phosphorus when phosphoric acid is produced; when phosphorus pentoxide is produced, no precipitation is performed and the impurities are discharged with the exhaust gas after combustion.

[0021] (4) Both the phosphorus pentoxide production unit and the phosphoric acid production unit produce steam as a by-product, which can be uniformly allocated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a principle block diagram of a production system for phosphorus pentoxide co-producing thermal phosphoric acid in an embodiment of the utility model;

[0023] Figure 2 is a principle block diagram of the second tail gas treatment structure;

[0024] Figure 3is the output schematic diagram of the cooling water supply device;

[0025] Figure 4 It is a schematic diagram of the output of the phosphorus burning tower gas supply device and the phosphorus burning gun gas supply device. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings.

[0027] See also Figure 1-4 The embodiment of the utility model provides a production system for phosphorus pentoxide co-production of thermal phosphoric acid, which includes a phosphoric acid production device, a phosphorus pentoxide production device, a cooling water supply device, a phosphorus burning tower air supply device, and a phosphorus burning gun air supply device. Among them, the cooling water supply device is used to supply cooling water, and the cooling water is desalted water. The phosphorus burning tower air supply device is used to supply dry air for reacting with yellow phosphorus. The phosphorus burning gun air supply device is used to supply compressed air for atomizing the liquid yellow phosphorus sprayed from the spray gun.

[0028] Among them, the phosphoric acid production device includes a yellow phosphorus storage tank, a sedimentation tank, a first trough, a first phosphorus burning tower, a hydration structure and a first tail gas treatment structure, etc. The yellow phosphorus storage tank, the sedimentation tank, the first trough, the first phosphorus burning tower, the hydration structure and the first tail gas treatment structure are connected in sequence through pipelines. The hydration structure includes two-stage hydration mechanisms (a primary hydration mechanism and a secondary hydration mechanism) connected in series through pipelines, and the hydration mechanism includes a hydration tower, a heat exchanger and a circulation tank connected end to end. The air inlet at the top of the hydration tower of the primary hydration mechanism is connected to the exhaust port at the top of the first phosphorus burning tower through a pipeline, the air inlet at the top of the hydration tower of the secondary hydration mechanism is connected to the exhaust port at the bottom of the hydration tower of the primary hydration mechanism through a pipeline, and the exhaust port at the bottom of the hydration tower of the secondary hydration mechanism is connected to the first tail gas treatment structure (specifically a venturi sprayer) through a pipeline. The circulation tank of the secondary hydration mechanism is connected to the circulation tank of the primary hydration mechanism through a pipeline with a pump to deliver dilute acid (concentration of about 30%) to the circulation tank of the primary hydration mechanism, and the wastewater outlet of the first exhaust gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline with a pump to deliver wastewater (concentration less than 10%) to the circulation tank of the secondary hydration mechanism.

[0029] Among them, the phosphorus pentoxide production device includes a second ground trough, a second phosphorus burning tower, a cooling tower (multiple cooling towers connected in series), a settling tower (multiple settling towers connected in series), a second tail gas treatment structure, a rotary vibrating screen, a spiral conveying structure, a coarse material silo, a powder material silo and a packaging structure at the bottom of the powder material silo. The yellow phosphorus storage tank, the second ground trough, the second phosphorus burning tower, the cooling tower, the settling tower and the second tail gas treatment structure are connected in sequence through pipelines. The spiral conveying structure is arranged between the discharge port at the bottom of the cooling tower and the feed port of the rotary vibrating screen (with a hose provided thereon). The rotary vibrating screen is higher than the coarse material silo and the powder material silo. The coarse material outlet and the fine material outlet of the rotary vibrating screen are respectively connected to the top of the coarse material silo and the powder material silo through a chute. The discharge port (outputting particulate matter) at the bottom of the coarse material silo is connected to the circulation trough of the primary hydration mechanism through a conveying structure (specifically a screw conveyor). The powder output from the powder material silo is sold as a product, and the powder output from the settling tower is also sold as a product. The wastewater outlet of the second tail gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline to send wastewater (concentration less than 10%) to the circulation tank of the secondary hydration mechanism. In this patent, phosphorus pentoxide reacts with water to release heat violently, so the phosphorus pentoxide output from the coarse material silo needs to be slowly added to the circulation tank of the primary hydration mechanism. The amount of phosphorus pentoxide is very small and can be achieved. When adding phosphorus pentoxide, the corresponding cooling jacket and heat exchanger are preferably operated close to full load.

[0030] Among them, heaters are provided in the yellow phosphorus storage tank, sedimentation tank, first trough and second trough, and heating jackets are provided on the corresponding pipelines. The first phosphorus burning tower and the second phosphorus burning tower are both provided with steam drums (described in application number CN201420318761.7), and the steam drums are connected to the heaters and heating jackets through pipelines (steam network).

[0031] Among them, the first phosphorus burning tower, the second phosphorus burning tower, the cooling tower, the powder silo and the hydration tower are all equipped with cooling jackets. The hot water outlets of the cooling jackets of the first phosphorus burning tower and the second phosphorus burning tower are connected to the corresponding steam drum (located above the corresponding phosphorus burning tower, which is an existing structure) through pipelines. The cooling water supply device is connected to the cooling jacket and the heat exchanger through pipelines to form a circulating cooling structure. The cooling water supply device includes a cooling water tower and a circulating tank, etc.

[0032] Furthermore, the phosphorus burning tower air supply device is connected to the air inlet of the first phosphorus burning tower and the second phosphorus burning tower through a pipeline, and the phosphorus burning gun air supply device is connected to the compressed air inlet of the spray gun on the first phosphorus burning tower and the second phosphorus burning tower through a pipeline. The phosphorus burning tower air supply device and the phosphorus burning gun air supply device can refer to the patent description with application number CN202120468716.X.

[0033] Among them, see Figure 2The second tail gas treatment structure in the embodiment of the utility model includes a cyclone separator, a packed spray tower, a first cyclone spray tower, a second cyclone spray tower, a fiber dust collector and a fan, etc., which are connected in sequence through pipelines. The air inlet of the cyclone separator is connected to the air outlet of the settling tower (the last one) through a pipeline. The wastewater outlets of the cyclone separator, the packed spray tower, the first cyclone spray tower, the second cyclone spray tower and the fiber dust collector are all connected to the wastewater main pipe, and the wastewater main pipe is connected to the circulation tank of the secondary hydration mechanism. The cyclone separator, the packed spray tower, the first cyclone spray tower and the second cyclone spray tower are all provided with nozzles, and the spray liquid is water. For the specific structure, please refer to the description of application number CN202120468714.0.

[0034] Among them, the structure of the first exhaust gas treatment structure in this embodiment can refer to the description of application number CN201720404492.X.

[0035] Among them, the mesh aperture of the rotary vibrating screen in the embodiment of the utility model is 2.0-3.5mm, specifically 2.5mm.

[0036] Among them, the first trough in the embodiment of the utility model is arranged next to the first phosphorus burning tower and is lower than the sedimentation tank, the second trough is arranged next to the second phosphorus burning tower, the sedimentation tank is a closed tank, and the yellow phosphorus storage tank, the first trough and the second trough are all closed tanks.

[0037] The "first" and "second" in this embodiment are only used for distinction and have no other special meaning. In this embodiment, a pump, a fan, a valve or a flow meter etc. are arranged on the pipelines between the structures as required.

[0038] 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 system for phosphorus pentoxide co-production of thermal phosphoric acid, the system comprising a phosphoric acid production device and a phosphorus pentoxide production device, the phosphoric acid production device comprising a yellow phosphorus storage tank, a settling tank, a first phosphorus burning tower, a hydration structure and a first tail gas treatment structure connected in sequence, the phosphorus pentoxide production device comprising a second phosphorus burning tower, a cooling tower, a settling tower and a second tail gas treatment structure connected in sequence, the first phosphorus burning tower and the second phosphorus burning tower are both provided with a steam drum, the yellow phosphorus storage tank and the settling tank are both provided with a heater, the hydration structure comprises a two-stage hydration mechanism connected in series, the hydration mechanism comprises a hydration tower, a heat exchanger and a circulation tank connected end to end; characterized in that The phosphorus pentoxide production device also includes a rotary vibrating screen, the feed port of the rotary vibrating screen is connected to the discharge port at the bottom of the cooling tower and the coarse material outlet is connected to the circulation tank of the primary hydration mechanism through a conveying structure, the waste water outlet of the second tail gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline; the feed port of the second phosphorus burning tower is connected to the yellow phosphorus storage tank through a pipeline, and the steam drum is connected to the heater through a pipeline.

2. The production system of phosphorus pentoxide co-production of thermal phosphoric acid according to claim 1, characterized in that: The mesh size of the rotary vibrating screen is 2.0-3.5 mm.

3. The production system of phosphorus pentoxide co-production of thermal phosphoric acid according to claim 1, characterized in that: The second exhaust gas treatment structure includes a cyclone separator, a packed spray tower, a first cyclone spray tower, a second cyclone spray tower, a fiber dust collector and a fan which are connected in sequence through pipelines. The air inlet of the cyclone separator is connected to the air outlet of the sedimentation tower through a pipeline. The wastewater outlets of the cyclone separator, the packed spray tower, the first cyclone spray tower, the second cyclone spray tower and the fiber dust collector are all connected to the wastewater main pipe, and the wastewater main pipe is connected to the circulation tank of the secondary hydration mechanism.

4. The production system of phosphorus pentoxide co-production of thermal phosphoric acid according to claim 1, characterized in that: The phosphoric acid production device also includes a first trough, and the phosphorus pentoxide production device also includes a second trough. The first trough is arranged next to the first phosphorus burning tower and is provided with a heater therein, and the second trough is arranged next to the second phosphorus burning tower and is provided with a heater therein. The first trough and the second trough are both closed troughs; the discharge port of the first trough is connected to the feed port of the first phosphorus burning tower through a pipeline, and the first trough is lower than the sedimentation tank, and its feed port is connected to the sedimentation tank through a pipeline; the discharge port of the second trough is connected to the feed port of the second phosphorus burning tower through a pipeline, and its feed port is connected to the yellow phosphorus storage tank through a pipeline.

5. The production system of phosphorus pentoxide and thermal phosphoric acid according to claim 1, characterized in that: The circulation tank of the secondary hydration mechanism is connected to the circulation tank of the primary hydration mechanism through a pipeline, and the wastewater outlet of the first tail gas treatment structure is connected to the circulation tank of the secondary hydration mechanism through a pipeline.

6. The production system of phosphorus pentoxide and thermal phosphoric acid according to claim 1, characterized in that: The phosphorus pentoxide production device also includes a spiral conveying structure, a coarse material silo, a powder material silo and a packaging structure at the bottom of the powder material silo. The spiral conveying structure is arranged between the discharge port of the cooling tower and the feed port of the rotary vibrating screen. The rotary vibrating screen is higher than the coarse material silo and the powder material silo. The coarse material outlet and the fine material outlet of the rotary vibrating screen are respectively connected to the top of the coarse material silo and the powder material silo through chutes, and the discharge port at the bottom of the coarse material silo is connected to the circulation groove of the primary hydration mechanism through the conveying structure.

7. The production system of phosphorus pentoxide and thermal phosphoric acid according to claim 6, characterized in that: The production system also includes a cooling water supply device. The first phosphorus burning tower, the second phosphorus burning tower, the cooling tower, the powder silo and the hydration tower are all provided with cooling jackets. The hot water outlets of the cooling jackets of the first phosphorus burning tower and the second phosphorus burning tower are connected to the corresponding steam drums through pipelines. The cooling water supply device is connected to the cooling jackets and the heat exchanger through pipelines.

8. The production system of phosphorus pentoxide and thermal phosphoric acid according to claim 1, characterized in that: The production system also includes a phosphorus burning tower air supply device and a phosphorus burning gun air supply device. The phosphorus burning tower air supply device is connected to the air inlet of the first phosphorus burning tower and the second phosphorus burning tower through a pipeline, and the phosphorus burning gun air supply device is connected to the compressed air inlet of the spray gun on the first phosphorus burning tower and the second phosphorus burning tower through a pipeline.

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