A method for improving ammonium sulfate production efficiency

Abstract

The present invention provides a method for improving the production efficiency of ammonium sulfate, comprising the following steps: a) transporting ammonium sulfate slurry to a crystallizer to establish a liquid level; starting a vacuum pump to establish negative pressure; starting a crystallization circulation pump to establish circulation; then controlling the temperature of the crystallizer to be 52°C to 55°C, the ammonium sulfate slurry is concentrated in the crystallizer, crystallization occurs, and after the solid content reaches 10%, the crystallization discharge pump is turned on; b) sequentially turning on a packaging machine and a centrifuge, opening a process from the crystallization discharge pump to a cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters a centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters a packaging machine for packaging to obtain an ammonium sulfate product. Compared with the prior art, the method for improving the production efficiency of ammonium sulfate provided by the present invention adopts specific process steps, conditions and parameters to achieve overall good interaction, and can increase the ammonium sulfate output by 20% under the condition that the quality of the ammonium sulfate product is qualified.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonium sulfate crystallization, and more specifically, to a method for improving the production efficiency of ammonium sulfate. Background Art

[0002] A centrifuge is a mechanical device that uses centrifugal force to separate liquids from solid particles or components in a liquid-liquid mixture. A centrifuge has a cylinder that rotates at high speed around its own axis, called a drum, which is usually driven by an electric motor. After the suspension (or emulsion) is added to the drum, it is quickly driven to rotate at the same speed as the drum. Under the action of centrifugal force, the components are separated and discharged separately. Generally, the higher the drum speed, the better the separation effect.

[0003] There are two working principles of centrifuges: centrifugal filtration and centrifugal sedimentation. Centrifugal filtration is to make the centrifugal pressure generated by the suspension in the centrifugal field act on the filter medium, so that the liquid passes through the filter medium to become filtrate, while the solid particles are trapped on the surface of the filter medium, thereby achieving liquid-solid separation; centrifugal sedimentation is to use the principle that the components of the suspension (or emulsion) with different densities quickly settle and stratify in the centrifugal field to achieve liquid-solid (or liquid-liquid) separation.

[0004] Industrial centrifuges can be divided into three categories according to their structure and separation requirements: filter centrifuges, sedimentation centrifuges and separators. Filter centrifuges and sedimentation centrifuges mainly rely on increasing the drum diameter to expand the working surface on the drum circumference; separators have additional working surfaces in addition to the drum circumference, such as the disc of a disc separator and the inner cylinder of a chamber separator, which significantly increase the sedimentation working surface.

[0005] An important indicator for measuring the separation performance of a centrifuge is the separation factor. It indicates the ratio of the centrifugal force to the gravity of the separated material in the drum. The larger the separation factor, the faster the separation and the better the separation effect. Another factor that determines the processing capacity of a centrifuge is the working area of ​​the drum. The larger the working area, the greater the processing capacity.

[0006] The finer the solid particles in the suspension, the more difficult it is to separate them, and the fine particles carried away in the filtrate or separated liquid will increase. In this case, the centrifuge needs to have a higher separation factor to effectively separate; when the viscosity of the liquid in the suspension is high, the separation speed slows down; the density difference between the components of the suspension or emulsion is large, which is beneficial to centrifugal sedimentation, while centrifugal filtration of the suspension does not require the components to have a density difference.

[0007] At present, the production efficiency of ammonium sulfate in the existing technology is low, the system energy consumption is high, and its centrifugal separation process is one of the main influencing factors. Summary of the invention

[0008] In view of this, the object of the present invention is to provide a method for improving the production efficiency of ammonium sulfate, by optimizing the process of ammonium sulfate evaporation and crystallization, using a high-efficiency centrifuge, improving the production efficiency of ammonium sulfate products, and reducing system energy consumption.

[0009] The present invention provides a method for improving the production efficiency of ammonium sulfate, comprising the following steps:

[0010] a) transporting the ammonium sulfate slurry to the crystallizer to establish the liquid level; starting the vacuum pump to establish negative pressure; starting the crystallization circulation pump to establish circulation; then controlling the crystallizer temperature to 52° C. to 55° C., the ammonium sulfate slurry is concentrated in the crystallizer, crystals appear, and after the solid content reaches 10%, the crystallization discharge pump is started;

[0011] b) starting the packaging machine and the centrifuge in sequence, opening the process from the crystallization discharge pump to the cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters the centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters the packaging machine for packaging to obtain an ammonium sulfate product.

[0012] Preferably, the total salt content flow rate of the ammonium sulfate slurry in step a) is 300,000 mg / l to 500,000 mg / l.

[0013] Preferably, the liquid level established in step a) is 1 m to 3 m.

[0014] Preferably, the negative pressure established in step a) is -0.09 MPa to -0.1 MPa.

[0015] Preferably, the method of controlling the crystallizer temperature in step a) is steam heating; the steam consumption is 1 t / h to 2 t / h.

[0016] Preferably, the pressure of the cyclone in step b) is 0.04 MPa to 0.08 MPa.

[0017] Preferably, the centrifuge in step b) is a spiral unloading centrifuge; the mesh size of the spiral unloading centrifuge is 0.07 mm to 0.09 mm, the rotation speed is 500 r / min to 2000 r / min, and the drum diameter of the concentration stage centrifuge is 500 mm to 600 mm.

[0018] Preferably, the centrifugal process in step b) is specifically as follows:

[0019] The ammonium sulfate slurry flows into the centrifuge by gravity, and the slurry undergoes a process of sedimentation filtration and then centrifugal separation in the centrifuge to obtain ammonium sulfate after centrifugation.

[0020] Preferably, the water content of the ammonium sulfate after centrifugation in step b) is less than 1%.

[0021] Preferably, the particle size of the ammonium sulfate product in step b) is 0.05 mm to 0.25 mm.

[0022] The present invention provides a method for improving the production efficiency of ammonium sulfate, comprising the following steps: a) conveying ammonium sulfate slurry to a crystallizer to establish a liquid level; starting a vacuum pump to establish negative pressure; starting a crystallization circulation pump to establish circulation; then controlling the temperature of the crystallizer to be 52°C to 55°C, the ammonium sulfate slurry is concentrated in the crystallizer, crystallization occurs, and after the solid content reaches 10%, the crystallization discharge pump is turned on; b) sequentially turning on a packaging machine and a centrifuge, opening a process from the crystallization discharge pump to a cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters a centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters a packaging machine for packaging to obtain an ammonium sulfate product. Compared with the prior art, the method for improving the production efficiency of ammonium sulfate provided by the present invention adopts specific process steps, conditions and parameters to achieve overall good interaction, and can increase the ammonium sulfate output by 20% under the condition that the quality of the ammonium sulfate product is qualified.

[0023] In addition, the present invention adopts a spiral unloading centrifuge, which does not need to continue to dry the product, and can meet the quality requirements of the ammonium sulfate product, and the cost per ton of ammonium sulfate product is reduced by 198.3 yuan / ton. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A process flow chart of a method for improving the production efficiency of ammonium sulfate provided in Example 1 of the present invention;

[0025] Figure 2 The process flow chart of the method for improving the production efficiency of ammonium sulfate provided in Comparative Example 3. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The present invention provides a method for improving the production efficiency of ammonium sulfate, comprising the following steps:

[0028] a) transporting the ammonium sulfate slurry to the crystallizer to establish the liquid level; starting the vacuum pump to establish negative pressure; starting the crystallization circulation pump to establish circulation; then controlling the crystallizer temperature to 52° C. to 55° C., the ammonium sulfate slurry is concentrated in the crystallizer, crystals appear, and after the solid content reaches 10%, the crystallization discharge pump is started;

[0029] b) starting the packaging machine and the centrifuge in sequence, opening the process from the crystallization discharge pump to the cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters the centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters the packaging machine for packaging to obtain an ammonium sulfate product.

[0030] The present invention firstly transports ammonium sulfate slurry to a crystallizer to establish a liquid level; starts a vacuum pump to establish negative pressure; starts a crystallization circulation pump to establish circulation; then controls the temperature of the crystallizer to be 52° C. to 55° C., the ammonium sulfate slurry is concentrated in the crystallizer, crystallization occurs, and after the solid content reaches 10%, starts a crystallization discharge pump.

[0031] In the present invention, the total salt content flow rate of the ammonium sulfate slurry is preferably 300000 mg / l to 500000 mg / l, more preferably 360000 mg / l to 380000 mg / l. The present invention has no special restrictions on the source of the ammonium sulfate slurry, and the ammonium sulfate slurry drawn from the bottom of the desulfurization tower into the slurry tank well known to those skilled in the art can be used.

[0032] The present invention delivers the ammonium sulfate slurry to the crystallizer to establish a liquid level; the height of the established liquid level is preferably 1m to 3m, more preferably 1m to 1.3m. The present invention has no special restrictions on the type and source of the crystallizer, and a commercially available evaporation crystallizer well known to those skilled in the art can be used; the delivery device is preferably a feed pump well known to those skilled in the art.

[0033] After a certain liquid level is established, the present invention turns on the vacuum pump to establish negative pressure; the pressure for establishing the negative pressure is preferably -0.09 MPa to -0.1 MPa, and more preferably -0.091 MPa to -0.097 MPa.

[0034] Afterwards, the crystallization circulation pump is turned on to establish a circulation so that the slurry circulates in the crystallizer; the temperature of the crystallizer is then controlled to be 52°C to 55°C to heat the slurry; the method of controlling the temperature of the crystallizer is preferably steam heating; the steam consumption is preferably 1t / h to 2t / h, and more preferably 1.4t / h to 1.6t / h.

[0035] On this basis, the ammonium sulfate slurry is concentrated in the crystallizer, and crystallization occurs (the slurry concentration in the crystallizer is 50%, reaching a saturated state and a crystal product is precipitated). After the solid content reaches 10%, the crystallization discharge pump is turned on.

[0036] Afterwards, the present invention starts the packaging machine and the centrifuge in sequence, opens the crystallization discharge pump (the flow rate from the crystallization discharge pump to the cyclone is controlled at about 200L / min), and transports the concentrated slurry to the cyclone. The ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters the centrifuge for centrifugation. The ammonium sulfate after centrifugation falls into the packaging machine for packaging to obtain an ammonium sulfate product.

[0037] In the present invention, the pressure of the cyclone is preferably 0.04MPa-0.08MPa, more preferably 0.05MPa-0.07MPa; on this basis, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters the centrifuge for centrifugation.

[0038] In the present invention, the centrifuge is preferably a spiral unloading centrifuge; the mesh gap of the spiral unloading centrifuge is preferably 0.07mm-0.09mm, more preferably 0.08mm, the rotation speed is preferably 500r / min-2000r / min, more preferably 1000r / min-1500r / min, and the drum diameter of the concentration section centrifuge is preferably 500mm-600mm, more preferably 550mm. The present invention adopts the above-mentioned spiral unloading centrifuge to improve the production efficiency of ammonium sulfate, and the process is simple, reliable, intuitive, practical, and highly instructive, which is conducive to improving the production efficiency of ammonium sulfate and reducing system energy consumption; experimental results show that the method provided by the present invention can increase the ammonium sulfate output by 20% under the condition of meeting the quality of ammonium sulfate products; and, by adopting the spiral unloading centrifuge, there is no need to continue to dry the product to meet the quality of ammonium sulfate products; the cost per ton of ammonium sulfate products is reduced by 198.3 yuan / ton.

[0039] In the present invention, the centrifugal process is preferably specifically as follows:

[0040] The ammonium sulfate slurry flows into the centrifuge by gravity, and the slurry undergoes a process of sedimentation filtration and then centrifugal separation in the centrifuge to obtain ammonium sulfate after centrifugation.

[0041] In the present invention, the density of the ammonium sulfate slurry entering the centrifuge by gravity meets 1200 kg / m 3 ~1350kg / m 3 The viscosity meets the 1.76mPa.s index, preferably 2.5m 3 / h~6.5m 3 / h flow rate enters the centrifuge.

[0042] In the present invention, the water content of the ammonium sulfate after centrifugation is preferably less than 1%, and more preferably less than or equal to 0.8%.

[0043] In the present invention, the ammonium sulfate after centrifugation passes through the ammonium sulfate product drying equipment from the centrifuge outlet, enters the intermediate warehouse through a spiral conveyor, is packaged by a packaging machine, and is stored. In the present invention, the particle size of the ammonium sulfate product is preferably 0.05 mm to 0.25 mm, and more preferably 0.08 mm to 0.2 mm.

[0044] In view of the problems of high energy consumption and low ammonium sulfate output in the existing ammonium sulfate evaporation and crystallization system, the present invention provides a method for improving the production efficiency of ammonium sulfate, which mainly includes the above-mentioned evaporation and crystallization process and the solid-liquid separation process. The production of qualified ammonium sulfate is the premise, and the water content of the ammonium sulfate product can be lower than 0.8% by the centrifuge alone, which meets the index of qualified ammonium sulfate by optimizing the process flow of the evaporation and crystallization system and improving the centrifugal efficiency of the centrifuge; the centrifuge export product can be directly packaged for takeout across the fluidized bed; in actual production, through process modification, the centrifuge export product can be directly delivered to the finished product warehouse across the fluidized bed, thereby increasing the output of ammonium sulfate and reducing the energy consumption of the crystallization system. In the actual production process, the present invention, on the one hand, increases the output of ammonium sulfate, which is beneficial to reducing the total salt of the desulfurization tower slurry and maintaining environmental protection emissions; on the other hand, it achieves a reduction in energy consumption of the crystallization system.

[0045] The present invention provides a method for improving the production efficiency of ammonium sulfate, comprising the following steps: a) conveying ammonium sulfate slurry to a crystallizer to establish a liquid level; starting a vacuum pump to establish negative pressure; starting a crystallization circulation pump to establish circulation; then controlling the temperature of the crystallizer to be 52°C to 55°C, the ammonium sulfate slurry is concentrated in the crystallizer, crystallization occurs, and after the solid content reaches 10%, the crystallization discharge pump is turned on; b) sequentially turning on a packaging machine and a centrifuge, opening a process from the crystallization discharge pump to a cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters a centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters a packaging machine for packaging to obtain an ammonium sulfate product. Compared with the prior art, the method for improving the production efficiency of ammonium sulfate provided by the present invention adopts specific process steps, conditions and parameters to achieve overall good interaction, and can increase the ammonium sulfate output by 20% under the condition that the quality of the ammonium sulfate product is qualified.

[0046] In addition, the present invention adopts a spiral unloading centrifuge, which does not need to continue to dry the product, and can meet the quality requirements of the ammonium sulfate product, and the cost per ton of ammonium sulfate product is reduced by 198.3 yuan / ton.

[0047] In order to further illustrate the present invention, the method for increasing the ammonium sulfate yield and reducing the energy consumption of the crystallization system provided by the present invention is described in detail by the following examples. The detailed process parameters of the crystallization system used in the following examples of the present invention are shown in Table 1.

[0048] Table 1

[0049] project Process data Fresh ammonium sulfate salt 370000mg / l Crystallization temperature 52℃～55℃ Crystallization pressure -0.091MPa~-0.097MPa Cyclone pressure 0.05MPa~0.07MPa Steam consumption 1.4t / h~1.6t / h Centrifuge speed 2000rpm(max) Centrifuge frequency conversion 50％～100％ Ammonium sulfate products contain water ≤0.8％ Ammonium sulfate production 1.5t / h~2t / h

[0050] Example 1

[0051] See the process flow chart of the method for improving the production efficiency of ammonium sulfate provided in this embodiment. Figure 1 As shown, the specific steps are as follows:

[0052] (1) Ammonium sulfate slurry with a total salt content of 370,000 mg / l is extracted from the bottom of the desulfurization tower at a flow rate of 4 t / h and enters the slurry tank. The liquid level of the slurry tank is established at 2m to 2.2m.

[0053] (2) Turn on the crystallization feed pump, maintain the pressure at 0.35MPa to 0.4MPa, and deliver the slurry in step (1) to the crystallizer. The crystallizer establishes a liquid level and maintains it at 1 to 1.3m. Turn on the vacuum pump and the upper condenser of the crystallizer, establish a negative pressure in the crystallizer, and control the pressure at -0.091 to -0.097MPa. Turn on the crystallization circulation pump, circulate the slurry in the crystallizer, and introduce steam into the crystallization heater to control the crystallizer temperature at 52 to 55°C.

[0054] (3) Turn on the crystallization discharge pump and control the pressure to 0.3MPa-0.4MPa. The slurry in step (2) is circulated through the cyclone sub-line to increase the concentration; under the joint action of the crystallization circulation pump, heater and vacuum pump, the slurry concentration in the crystallizer gradually increases. Sampling and testing are carried out at regular intervals. When the solid content reaches 10%, the slurry is transferred to the cyclone.

[0055] (4) Open the slurry inlet valve of the hydrocyclone, close the hydrocyclone secondary valve, and transfer the slurry in step (3) to the hydrocyclone. Control the hydrocyclone inlet pressure to 0.05-0.07 MPa. After the hydrocyclone, the solid content of the slurry reaches 40%, and the supernatant of the hydrocyclone returns to the slurry tank.

[0056] (5) Turn on the centrifuge, and control the frequency conversion of the centrifuge to 40% to 60%. The ammonium sulfate slurry in step (4) flows into the centrifuge by gravity, and the slurry undergoes a process of sedimentation filtration and then centrifugal separation in the centrifuge. The centrifuge filter mesh gap is selected to be 0.08 mm, the speed of the centrifuge is controlled to be 1000 r / min, and the diameter of the centrifuge drum in the concentration stage is 550 mm. The water content of the exported ammonium sulfate product is less than 0.8%, and the particle size of the ammonium sulfate product is 0.08 to 0.2 mm, which meets the requirements of qualified ammonium sulfate products.

[0057] (6) The ammonium sulfate product in step (5) is directly sent to the ammonium sulfate storage bin across the vibrating fluidized bed and its ancillary equipment, and then the product is packaged and sold out through the ammonium sulfate packaging line, with an ammonium sulfate output of 1.5 to 2 t / h.

[0058] Comparative Example 1

[0059] The method for improving the production efficiency of ammonium sulfate provided in Example 1 is adopted; the difference is that: in step (4), the pressure of the cyclone inlet is controlled to be 0.1-0.15 MPa, and the solid content of the ammonium sulfate slurry at the cyclone outlet is more than 50%.

[0060] Comparative Example 2

[0061] The method for improving the production efficiency of ammonium sulfate provided in Example 1 is adopted; the difference is that: in step (4), the mesh gap of the centrifuge filter is selected to be 0.08 mm, the rotation speed of the centrifuge is controlled to be 1500 r / min, and the drum diameter of the centrifuge in the concentration stage is 550 mm.

[0062] Comparative Example 3

[0063] The method for improving the production efficiency of ammonium sulfate provided in Example 1 is adopted; the difference is that: in step (4), the mesh gap of the centrifuge filter is selected to be 0.08 mm, the speed of the centrifuge is controlled to be 700 r / min, the drum diameter of the centrifuge in the concentration stage is 550 mm, and in order to obtain an ammonium sulfate product with the same purity as in Example 1, a vibrating fluidized bed device is turned on (see Figure 2 shown).

[0064] The methods for improving the production efficiency of ammonium sulfate provided in Example 1 and Comparative Examples 1 to 3 were used to test the data of ammonium sulfate production and energy consumption. The results are shown in Table 2.

[0065] Table 2

[0066] parameter Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ammonium sulfate production 1.7t / h 1.4t / h 1.4t / h 1.7t / h Crystallization system power consumption 146.5Kw 146.5Kw 157.8Kw 246.8Kw Crystallization steam consumption 1.4t / h 1.4t / h 1.4t / h 1.7t / h Ammonium sulfate products contain water 0.8％ 0.77％ 0.75％ 0.8％

[0067] The experimental results show that the method provided by Example 1 of the present invention is simple in process, low in cost, pollution-free, and can operate stably for a long time; and the prepared ammonium sulfate product has a water content of less than 0.8%, and the product quality is stable; in addition, the ammonium sulfate output of the method provided by the present invention is increased by more than 20% compared with the traditional process, and the ton cost of ammonium sulfate is reduced by 198.3 yuan / t; low energy consumption and high efficiency production of ammonium sulfate is achieved, the economic value of the product is improved, and the operation has more advantages.

[0068] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the production efficiency of ammonium sulfate, comprising the following steps: a) transporting the ammonium sulfate slurry to the crystallizer to establish the liquid level; starting the vacuum pump to establish negative pressure; The crystallization circulation pump is turned on to establish circulation; then the temperature of the crystallizer is controlled to be 52° C. to 55° C., the ammonium sulfate slurry is concentrated in the crystallizer, crystallization occurs, and after the solid content reaches 10%, the crystallization discharge pump is turned on; b) starting the packaging machine and the centrifuge in sequence, opening the process from the crystallization discharge pump to the cyclone, the ammonium sulfate slurry is further concentrated in the cyclone, and after the solid content reaches 40%, it enters the centrifuge for centrifugation, and the ammonium sulfate after centrifugation enters the packaging machine for packaging to obtain an ammonium sulfate product.

2. The method for improving the production efficiency of ammonium sulfate according to claim 1, wherein: The total salt content flow rate of the ammonium sulfate slurry in step a) is 300,000 mg / l to 500,000 mg / l.

3. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The liquid level established in step a) is 1 m to 3 m.

4. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The negative pressure established in step a) is -0.09 MPa to -0.1 MPa.

5. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The method of controlling the crystallizer temperature in step a) is steam heating; the steam consumption is 1t / h to 2t / h.

6. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The pressure of the cyclone in step b) is 0.04 MPa to 0.08 MPa.

7. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The centrifuge in step b) is a spiral unloading centrifuge; the mesh gap of the spiral unloading centrifuge is 0.07mm-0.09mm, the rotation speed is 500r / min-2000r / min, and the drum diameter of the concentration stage centrifuge is 500mm-600mm.

8. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The centrifugal process in step b) is specifically as follows: The ammonium sulfate slurry flows into the centrifuge by gravity, and the slurry undergoes a process of sedimentation filtration and then centrifugal separation in the centrifuge to obtain ammonium sulfate after centrifugation.

9. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The water content of the ammonium sulfate after centrifugation in step b) is less than 1%.

10. The method for improving the production efficiency of ammonium sulfate according to claim 1, characterized in that: The particle size of the ammonium sulfate product in step b) is 0.05 mm to 0.25 mm.

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