Sieve plate type carbonizer for carbonation in sodium carbonate production

Abstract

The utility model discloses a sieve plate type carbonization tower for carbonization in soda ash production. The sieve plate type carbonization tower sequentially comprises a lower end cooling section, a middle crystallization section and an upper absorption section, the middle crystallization section and the upper absorption section are of sieve plate structures and comprise a plurality of layers of sieve plates, and a plurality of sieve holes are formed in the sieve plates; at least one layer of non-perforated sieve plate is arranged at the top of the carbonization tower, and a hydrocyclone separation device is arranged on the non-perforated sieve plate and is used for separating and recycling fog drops in the tail gas. The non-perforated sieve plate is additionally arranged at the top of the carbonization tower, and the cyclone hydraulic separation device is arranged on the sieve plate, so that fog drops in tail gas can be separated and recycled, scar blocks can be effectively prevented from falling onto the sieve plate tower plate and blocking sieve holes during tower falling, and the situation that when the liquid level in the tower is lower than the first sieve plate, the gas velocity of the sieve holes is high, and the fog drops are carried in discharged gas can be prevented; compared with a cap different-diameter carbonization tower, the production capacity is improved by at least 60%-85%, the sieve plate efficiency is improved by about 20%, the resistance is reduced by about 30%, and the manufacturing cost is reduced by about 30%.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical production equipment. Specifically, it particularly relates to a sieve-plate carbonation tower for soda ash production carbonation. Background Technique

[0002] The carbonation process is the heart of soda ash production, and the carbonation tower (also known as the carbonating tower) is the key equipment in the carbonation process. Once the type of carbonation tower is determined, it directly affects the completion of various indicators of future soda ash production, the level of consumption, the quality of the product, and even the level of investment.

[0003] When the carbonation tower is used in soda ash production, the three processes of mass transfer, crystallization, and heat transfer occur simultaneously in the tower, and there are gas, liquid, and solid phases. There are many factors affecting the working quality and production capacity. The requirements for the structure of the carbonating tower are: on the premise of meeting high utilization rate of sodium chloride, good NaHCO3 crystallization quality (large and uniform crystal grains), high CO2 utilization rate, and easy production automatic control operation, strive to have a large production capacity.

[0004] Due to the existence of gas, liquid, and solid phases in the carbonation process, it is required that the gas-liquid two phases have good contact in terms of structure, and the produced solid will not sink and block the gas-liquid channels, and a large amount of reaction heat should be removed in time to ensure the most suitable removal temperature. At present, major domestic soda ash plants generally use a cast iron mushroom cap structure variable-diameter carbonation tower (φ3000 / φ3400×~29895), such as Figure 1 As shown, the lower cooling section mainly includes a base 1', a gas distributor 2', a cooling water tank 4', a cooling water tank mushroom cap 3', a middle section air inlet tower ring 5', a middle section air box 6', etc.; the middle absorption section mainly includes a variable-diameter φ3000 / φ3400 tower ring 7' (H = 900), a φ3400 tower ring 9' (H = 700), a φ3400 mushroom cap 8'; the upper absorption section mainly includes a φ3000 tower ring 10' (H = 550), a φ3000 mushroom cap 11', and the tower top is composed of 2 pieces of φ3000 tower rings 12' (H = 1000) and a tower cover 13'.

[0005] At present, soda ash users require reducing the iron content in soda ash to improve the whiteness of soda ash. However, the existing cast iron mushroom cap carbonation tower has poor corrosion resistance, which increases the iron content in soda ash and affects the product whiteness. In addition, due to certain corrosion of the cast iron material, especially the corrosion of the mushroom cap inside the tower, the ammonia brine inlet position at the top, and the gas-liquid coexistence part at the tower top is serious, resulting in a short equipment life, a large amount of maintenance work usually, and problems such as low absorption rate, fine crystallization, serious corrosion, and red soda ash. In addition, there is a problem of mist droplets in the tail gas of the current mainstream cast iron mushroom cap carbonation tower, which affects the treatment of the carbonation tail gas by subsequent equipment; and the carbon dioxide in the tail gas is at a relatively high level (the content reaches about 8%), and the carbonation absorption efficiency is not high.

[0006] The single - unit production capacity of the traditional cast - iron bacteria - cap carbonating tower is about 230 tons per day. At present, the development trend of soda ash enterprises in China towards large production capacity is very obvious. The production scale of the ammonia - soda process is basically over one million tons per year. Large production capacity necessarily requires high - production - capacity equipment to match it. The carbonating tower is the core equipment for soda ash production, and there is an urgent need for new high - production - capacity equipment. Summary of the Utility Model

[0007] The utility model aims to provide a sieve - plate type carbonating tower for soda ash production. By adding a layer of non - perforated sieve plate at the top of the carbonating tower and arranging a hydro - cyclone separation device on the sieve plate, the fog droplets in the tail gas can be separated and recovered. At the same time, it can effectively prevent scale blocks from falling onto the sieve - plate tower plates during tower inversion and blocking the sieve holes.

[0008] To achieve the above - mentioned purpose, the utility model provides a sieve - plate type carbonating tower for soda ash production, which sequentially includes a lower cooling section, a middle crystallization section, and an upper absorption section; the middle crystallization section and the upper absorption section are of sieve - plate structures. The middle crystallization section and the upper absorption section include several layers of sieve plates, and a plurality of sieve holes are arranged on the sieve plates; at least one layer of non - perforated sieve plate is arranged at the top of the carbonating tower, and a hydro - cyclone separation device is arranged on the non - perforated sieve plate for separating and recovering the fog droplets in the tail gas.

[0009] In a preferred embodiment of the utility model, the hydro - cyclone separation device includes a bottom plate and a hydro - cyclone barrel. The bottom plate is connected to the tower body, the hydro - cyclone barrel is arranged at the middle position of the bottom plate, and a hydro - cyclone liquid return channel to the lower layer is arranged in the hydro - cyclone barrel. The hydro - cyclone barrel solves the problem of liquid entrainment by the gas by changing the gas flow rate and flow direction at this position.

[0010] In a preferred embodiment of the utility model, 90 - 150 sieve holes are arranged on each sieve plate in the tower rings of the middle crystallization section and the upper absorption section, and the hole - opening rate of the sieve plate is 1.0% - 2.8%.

[0011] In a preferred embodiment of the utility model, a plurality of sieve holes are arranged in a triangular shape on the sieve plate.

[0012] In a preferred embodiment of the utility model, the diameter size φ of the sieve holes is 14 - 45 mm, and the distance between sieve plates is 550 - 1000 mm.

[0013] In a preferred embodiment of the utility model, the overall height H of the sieve - plate type carbonating tower is 28800 - 30500 mm; the diameter of the tower ring at the upper absorption section is φ2800 - φ3400 mm, and the diameter of the middle crystallization section is φ3000 - φ3600 mm.

[0014] In a preferred embodiment of the present utility model, the middle crystallization section includes multiple cooling water tanks arranged vertically, and a cooling water tank cap is provided at the upper end of each cooling water tank; a middle section intake tower ring is arranged between the cooling water tanks, and the middle section air box is clamped between the middle section intake tower ring and the adjacent cooling water tank.

[0015] In a preferred embodiment of the present utility model, the tower bodies of the middle crystallization section and the upper absorption section are made of 316L stainless steel composite plate material or TA1 composite plate material.

[0016] In a preferred embodiment of the present utility model, the sieve plate type carbonization tower further includes a gas distributor arranged between the base and the cooling water tank.

[0017] In a preferred embodiment of the present utility model, the sieve plate type carbonization tower further includes a downcomer arranged at the eccentric position of each sieve plate. The diameter of the downcomer is φ = 500 - 750 mm, and the height of the liquid seal liquid level H1 = 180 - 350 mm.

[0018] In a preferred embodiment of the present utility model, the lower cooling section includes 8 cooling water tanks, and the upper absorption section and the middle crystallization section are integrally formed and are flange - connected to the lower cooling section.

[0019] The beneficial effects of the present utility model are as follows:

[0020] 1) By adding an unperforated sieve plate at the top of the carbonization tower and arranging a hydro - cyclone separator on the sieve plate, the present utility model can separate and recover the droplets existing in the tail gas. At the same time, it can effectively prevent scale blocks from falling onto the sieve plates of the sieve plate tower when the tower is inverted, blocking the sieve holes, and can also prevent the gas from carrying droplets when the liquid level in the tower is lower than the first sieve plate due to the high gas velocity through the sieve holes.

[0021] 2) The sieve plate structure with a low hole - opening rate is adopted in the middle - upper part tower ring of the carbonization tower. For example, the hole - opening rate of the sieve plate is 1.0% - 2.8%, which can improve the absorption efficiency of the carbonization tower, effectively reduce the carbon dioxide content in the tail gas, and is beneficial to the subsequent treatment of the carbonization tail gas by subsequent equipment, greatly reducing the impact of the discharged tail gas on the environment.

[0022] 3) To address the problems of low absorption rate and fine crystallization, the present utility model uses a sieve plate structure to replace the cast iron bacteria cap structure in the absorption section tower ring of the variable-diameter carbonization tower. A sieve plate structure with sieve holes is used in the upper absorption section tower ring, and the structure and dimensions of the carbonization tower are adjusted. Through analysis and design, the middle crystallization section, the tower body diameter, height, internal component spacing, and internal component type of the upper absorption section of the carbonization tower are redesigned and arranged. The internal components adopt a sieve plate structure, and important technical parameters such as the sieve plate opening rate, opening size and position arrangement, downcomer opening size and position arrangement, and liquid seal liquid level height are designed and improved. As a result, the absorption rate is increased, the crystallization effect is better, and the daily output of the entire tower is increased to 400 tons. Compared with the bacteria cap variable-diameter carbonization tower, the production capacity of the entire tower is increased by at least 60% - 85%, the plate efficiency is about 20% higher, the resistance is about 30% smaller, the cost is reduced by about 30%, and it is easy to install and clean. At the same time, the operation cycle of a single tower is extended.

[0023] 4) The carbonization tower with a sieve plate structure has good foaming of the two phases, a large gas-liquid contact surface, good absorption efficiency, the reaction zone moves upward, and the CO2 content in the tail gas is high; the sieve plate can effectively inhibit axial backmixing; the radial mixing on the sieve plate is good, providing conditions for a lower supersaturation for the precipitation of NaHCO3 crystals and larger crystal sizes in production; thus solving the problems of low absorption rate and fine crystallization in the bacteria cap type carbonization tower, increasing the absorption rate, and making the crystallization effect better.

[0024] 5) To address the problem that the corrosion of the bacteria cap in the tower increases the iron content and affects the whiteness of the product, the present utility model changes the bacteria cap of the cooling section water tank to 316L stainless steel material or TA2 material. At the same time, the internal components of the upper absorption section and the middle crystallization section are changed to a sieve plate structure and are also made of 316L stainless steel material or TA2 material; the shell material is selected as 316L stainless steel explosion composite plate material (which ensures both the strength of the equipment and that the part in contact with the material is made of 316L stainless steel material or TA2 material), thereby improving the corrosion resistance, effectively reducing the iron content in the alkali, and increasing the whiteness of the soda ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a cast iron bacteria cap variable-diameter carbonization tower in the prior art;

[0026] Figure 2 is a schematic structural diagram of the sieve plate type carbonization tower of the present application;

[0027] Figure 3 is a schematic position structure diagram of the cooling water tank and the cooling water tank bacteria cap of the present application;

[0028] Figure 4 is a schematic diagram of the sieve hole structure arranged in a triangular shape in the sieve plate type carbonization tower of the present application;

[0029] Figure 5 It is a schematic structural diagram of the hydrocyclone separation device of the present application. Specific Embodiments

[0030] The following will further elaborate on the present utility model in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative and explanatory purposes of the present utility model, and should not be construed as limiting the protection scope of the present utility model. All technologies implemented based on the above content of the present utility model are covered within the scope intended to be protected by the present utility model.

[0031] As Figure 2 shown, the present utility model provides a sieve-plate type carbonation tower for soda ash production carbonation, which successively includes a lower cooling section, a middle crystallization section, and an upper absorption section; the middle crystallization section and the upper absorption section are of sieve-plate structures, and the middle crystallization section and the upper absorption section include several layers of sieve plates 7, and a plurality of sieve holes are arranged on the sieve plates 7. Among them, at least one layer of non-perforated sieve plates is provided at the top of the carbonation tower, and a hydrocyclone separation device is provided on the non-perforated sieve plates for separating and recovering the droplets existing in the tail gas.

[0032] By adding one layer of non-perforated sieve plates at the top of the carbonation tower and arranging a hydrocyclone separation device on the sieve plates, the present utility model can separate and recover the droplets existing in the tail gas, and at the same time can effectively prevent scale blocks from falling onto the sieve plates of the sieve-plate tower when the tower is reversed, blocking the sieve holes, and can prevent the gas from carrying droplets when the liquid level in the tower is lower than the first sieve plate due to the high gas velocity through the sieve holes.

[0033] As Figure 5 shown, the hydrocyclone separation device 8 includes a bottom plate 81 and a cyclone barrel 82. The bottom plate 81 is connected to the tower body, the cyclone barrel 82 is arranged at the middle position of the bottom plate 81, and a cyclone liquid return channel to the lower layer is arranged in the cyclone barrel 82. The cyclone barrel solves the problem of gas carrying liquid by changing the gas flow velocity and flow direction at this position.

[0034] As Figure 4 shown, the sieve hole structure in the sieve-plate type carbonation tower can be arranged in a triangular shape.

[0035] Preferably, 90 - 150 sieve holes are arranged on each of the sieve plates 7 in the tower rings of the middle crystallization section and the upper absorption section, and the hole opening rate of the sieve plates is 1.0% - 2.8%.

[0036] The sieve-plate structure with a low hole opening rate is adopted for the middle and upper tower rings of the carbonation tower, which can improve the absorption efficiency of the carbonation tower, effectively reduce the carbon dioxide content in the tail gas, and at the same time is beneficial to the subsequent equipment for treating the carbonation tail gas, greatly reducing the impact of the discharged tail gas on the environment.

[0037] Preferably, the size of the sieve holes φ = 14 - 45 mm, and the sieve plate spacing is 550 - 1000 mm.

[0038] Controlling the size of the sieve holes within the above range can ensure that the gas is in full contact with the liquid during the flow from the lower part to the upper part and reacts, while maintaining the gas-liquid balance in the tower to reach the optimal reaction state, effectively reducing energy consumption and improving efficiency. If the sieve hole size is too large, it is easy to cause insufficient gas-liquid contact and short residence time of the gas in the tower, reducing the reaction efficiency of the entire tower; conversely, if the sieve hole size is too small, it is easy to cause an increase in the resistance in the tower, and it is easy to cause the sieve plate holes to be blocked due to scarring during the reaction process, resulting in a shortened operation cycle of the entire tower.

[0039] The present utility model controls the spacing of the sieve plates within the above range, mainly considering that a suitable hole spacing can ensure the formation of a stable gas cushion layer below the sieve plate, which is beneficial to the reaction in the tower.

[0040] Preferably, a plurality of sieve holes are preferably arranged in a triangular shape on the sieve plate 7, which is beneficial to the uniform contact of the gas with the liquid.

[0041] Such as Figure 2 shown, the overall height H of the sieve plate type carbonization tower is preferably 28800 - 30500 mm. The tower body diameter at the upper absorption section is φ3000 - φ3400 mm, and the diameter of the middle crystallization section is φ3000 mm - φ3600 mm.

[0042] For example, in a specific embodiment, the overall height of the sieve plate type carbonization tower is H = 29765 mm, the diameter of the middle crystallization section is φ = 3000 mm; the diameter of the tower ring 8 at the upper absorption section is φ = 3000 mm; the height of each tower ring 8 is h = 945 mm.

[0043] The present utility model redesigns and arranges the height, internal part spacing, and internal part type of the carbonization tower. The internal part adopts a sieve plate structure, and important technical parameters such as the sieve plate opening ratio, opening size and position, downcomer opening size and position, and liquid seal liquid level height are designed and arranged for improvement to meet the process requirements of the gas-liquid reaction in the tower.

[0044] Such as Figure 2 and 3 shown, the middle crystallization section of the sieve plate type carbonization tower includes a plurality of vertically arranged cooling water tanks 3, and a cooling water tank cap 6 is provided at the upper end of each cooling water tank 3; a middle section intake tower ring 4 is arranged between the cooling water tanks 3, a middle section gas box 5 is clamped between the middle section intake tower ring 4 and the adjacent cooling water tank 3, and a gas distributor 2 is arranged between the base 1 and the cooling water tank 3.

[0045] In the present utility model, the bacterium cap of the cooling section water tank is changed to 316L stainless steel material or TA2 material. Meanwhile, the internal components of the upper absorption section and the middle crystallization section are changed to sieve plate structures and are also made of 316L stainless steel material or TA2 material; the shell material is selected as 316L stainless steel explosion composite plate material. The design of this structure can not only improve the manufacturing efficiency of the equipment itself and reduce production costs, but also greatly improve the service life of the entire equipment.

[0046] Compared with the existing cast iron bacterium cap structure variable diameter carbonization tower, the present utility model changes the bacterium cap structure of the absorption crystallization section to an overflow tube type sieve plate, and the advantages are as follows:

[0047] 1) The foaming of the two phases on the sieve plate is good, there is a large gas-liquid contact surface, the absorption efficiency is good, the reaction zone moves upward, and the CO2 content in the tail gas is high;

[0048] 2) The sieve plate can effectively inhibit the axial backmixing;

[0049] 3) The radial mixing on the sieve plate is good, providing conditions for a relatively low supersaturation for the precipitation of NaHCO3 crystals, and the produced crystal grains are larger, thus solving the problems of low absorption rate and fine crystals in the bacterium cap type carbonization tower, improving the absorption rate, having a good crystallization effect, and increasing the output of the whole tower by at least 15% - 20%.

[0050] For the entire carbonization process, since the CO2 content in the tail gas of the sieve plate carbonization tower is high, a carbonization tail gas scrubbing tower can also be set in the process. The tail gas of the soda making and cleaning tower is used to deeply pre-carbonize the carbonated ammonium brine pumped out of the cleaning tower, which can increase the CO2 concentration in the liquid phase of the carbonated ammonium brine.

[0051] Preferably, the sieve plate type carbonization tower further includes a downcomer, which is arranged at the eccentric position of each layer of sieve plate, thus forming a gas flow channel with sieve plate holes and a liquid flow channel with the downcomer, and ensuring the formation of a gas cushion layer below the sieve plate, so that the gas and liquid in the tower are fully contacted to realize chemical reactions.

[0052] Preferably, the diameter size of the downcomer is φ = 500 - 750; the liquid seal liquid level height H1 = 180 - 350 mm. By controlling the downcomer size and the liquid seal surface height within the above ranges, it can better meet the process reaction conditions of the materials in the tower and ensure the gas-liquid balance in the tower.

[0053] The middle crystallization section and the upper absorption section of the sieve plate type carbonization tower of the present utility model are produced and installed as a whole, and are only connected to the lower cooler by a pair of equipment flanges, which greatly facilitates the on-site installation of the equipment. At the same time, the middle crystallization section and the upper absorption section as a whole also effectively avoid problems such as leakage at the flange position that may occur in the original multi-flange connection.

[0054] In the present utility model, the top and the middle part are fabricated as a whole and made of 316L material, effectively avoiding the corrosion problem caused by severe gas-liquid erosion at the nozzle of the connecting pipe, and at the same time completely solving the serious corrosion problem of the tower body caused by the gas-liquid alternation at the top of the tower, greatly improving the service life of the whole tower.

[0055] Compared with the bubble-cap carbonating tower with different diameters of the mushroom cap, the sieve-plate carbonating tower of the present utility model has a production capacity of up to 400 tons per day, an increase of at least 60% - 85%, a plate efficiency about 20% higher, a resistance about 30% smaller, a cost reduction of about 30%, and is easy to install and clean. At the same time, the operation cycle of a single tower is increased, and the crystal size and output of NaHCO3 can be effectively improved.

[0056] Embodiment 1

[0057] As Figure 2 shown, a sieve-plate carbonating tower includes a lower cooling section, a middle crystallization section and an upper absorption section; a layer of non-perforated sieve plate is provided at the top of the carbonating tower, and a hydrocyclone separator is provided on the non-perforated sieve plate. The overall height H of the carbonating tower is 30500 mm, the diameter of the tower ring at the upper absorption section is φ3400 mm, and the diameter of the middle crystallization section is φ3400 mm.

[0058] The middle crystallization section and the upper absorption section are made of 316L stainless steel composite plate material, including several layers of sieve plates. 110 sieve holes are arranged on the sieve plates of the middle crystallization section and the upper absorption section, arranged in a triangular shape. The hole opening rate of the upper absorption section is 1.6%, and the hole opening rate of the middle crystallization section is 2.0%. The diameter size of the sieve holes is φ = 16 - 35 mm, and the sieve plate spacing is 800 mm. The diameter size of the downcomer is φ = 500; the height of the liquid seal liquid level is H1 = 180 - 350 mm.

[0059] The absorption conversion rate of the sieve-plate carbonating tower is 75%, the crystallization effect is good and the average crystal size is 120 um. The output of the whole tower is increased by at least 85%, the sieve plate efficiency is about 20% higher, the resistance is about 30% smaller, and the cost is reduced by about 30%.

[0060] The above describes the embodiments of the present utility model. However, the present utility model is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A sieve-plate carbonation tower for soda ash production carbonation, characterized in that It successively includes a lower cooling section, a middle crystallization section, and an upper absorption section; the middle crystallization section and the upper absorption section are sieve plate structures. The middle crystallization section and the upper absorption section include several layers of sieve plates (7), and a plurality of sieve holes are arranged on the sieve plates (7); at least one layer of non-perforated sieve plate is provided at the top of the carbonation tower, and a hydrocyclone separator (8) is provided on the non-perforated sieve plate, configured to separate and recover the droplets present in the tail gas.

2. The sieve plate type carbonation tower for soda ash production carbonation according to claim 1, wherein, The hydrocyclone separator (8) includes a bottom plate (81) and a hydrocyclone barrel (82). The bottom plate (81) is connected to the tower body. The hydrocyclone barrel (82) is arranged at the middle position of the bottom plate (81). A swirling liquid return to the lower layer channel is arranged in the hydrocyclone barrel (82). The hydrocyclone barrel solves the problem of liquid entrainment by the gas by changing the flow rate and flow direction of the gas at this position.

3. The sieve plate type carbonation tower for soda ash production carbonation according to claim 1, characterized in that, 90 to 150 sieve holes are arranged on each of the sieve plates (7) in the tower rings of the middle crystallization section and the upper absorption section, and the opening ratio of the sieve plates is 1.0% to 2.8%.

4. The sieve-plate carbonation tower for soda ash production carbonation according to claim 1, characterized in that, The diameter size φ of the sieve holes is 14 to 45 mm, and the sieve plate spacing is 550 to 1000 mm.

5. The sieve plate type carbonation tower for soda ash production carbonation according to claim 1, characterized in that, The overall height H of the sieve plate type carbonation tower is 28800 to 30500 mm; The diameter of the tower ring at the upper absorption section is φ = 2800 to 3400 mm, and the diameter of the middle crystallization section is φ = 3000 to 3600 mm.

6. The sieve-plate carbonation tower for soda ash production carbonation according to claim 1, characterized in that, The middle crystallization section includes multiple vertically arranged cooling water tanks (3). A cooling water tank cap (6) is provided at the upper end of each cooling water tank (3); a middle section inlet tower ring (4) is arranged between the cooling water tanks (3), and a middle section gas box (5) is clamped between the middle section inlet tower ring (4) and the adjacent cooling water tank (3).

7. The sieve-plate carbonation tower for soda ash production carbonation according to claim 1, characterized in that, It also includes a gas distributor (2) arranged between the base (1) and the cooling water tank (3).

8. The sieve-plate carbonation tower for soda ash production carbonation according to claim 1, characterized in that, The sieve plate type carbonation tower also includes a downcomer arranged at the eccentric position of each layer of sieve plate. The diameter size of the downcomer is φ = 500 to 750 mm, and the liquid seal liquid level height H1 = 180 to 350 mm.

9. The sieve-plate carbonation tower for soda ash production carbonation according to any one of claims 1 to 8, characterized in that, The lower cooling section includes 8 cooling water tanks (3), and the upper absorption section and the middle crystallization section are integrally formed and are connected to the lower cooling section by flanges.

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