Tubular reactor
The tubular reactor addresses thermal decomposition and explosion risks in ammonium nitrate production by integrating ammonia supplementation and cooling solution supply, achieving stable temperature and pH control through optimized flow distribution and heat transfer.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- OTKRYTOE AKTSIONERNOE OBSHCHESTVO KRASNOJARSKIJ ZAVOD TSVETNYKH METALLOV IMENI V N GULIDOVA
- Filing Date
- 2025-06-05
- Publication Date
- 2026-05-15
AI Technical Summary
Existing tubular reactors for producing ammonium nitrate lack effective cooling systems and ammonia supplementation, leading to potential thermal decomposition and explosion risks due to increased temperature and acidification.
A tubular reactor design incorporating chambers for reagent mixing, additional ammonia feeding, and a cooling solution supply, along with optimized flow distribution and temperature control, using a recycled ammonium nitrate solution for cooling, ensures stable temperature and pH levels, reducing thermal decomposition risks.
The design effectively maintains safe temperature and pH levels, significantly reducing the risk of ammonium nitrate thermal decomposition and explosion by ensuring uniform media distribution and efficient heat transfer.
Smart Images
Figure RU2025050165_15052026_PF_FP_ABST
Abstract
Description
[0001] MTIK BOU 19 / 26
[0002] Tubular reactor
[0003] Field of technology
[0004] The utility model relates to a tubular reactor that can be used for the production of ammonium nitrate.
[0005] State of the art
[0006] From patent EP0272974B1, published on 15.09.1993, a tubular reactor for neutralizing acids with ammonia is known, comprising a reagent injection zone, a reaction zone, and an outlet pipe for finished products, characterized in that said reactor includes a first converging-expanding nozzle located in the reaction zone immediately after the reagent injection zone, and a converging-expanding nozzle at the outlet from the reaction zone immediately before the outlet pipe for finished products.
[0007] A disadvantage of the known technical solution is the lack of possibility for additional supply of ammonia and the ability to cool the reactor, which can lead to acidification of the environment and an increase in temperature, which contributes to the thermal decomposition of ammonium nitrate with a subsequent explosion.
[0008] As the closest analogue, one can choose the technical solution disclosed in patent RU2146557C1, published on 20.03.2000, which discloses a reactor for the production of ammonium salts, containing a tubular reaction chamber, at least a first ammonia feeder and at least one acid feeder, located in the first front or upstream part of this reactor, characterized in that it contains a second part, located in the continuation of its first part and containing in the direction from top to bottom along the flow a narrowing section, a cylindrical section and an expanding section, a second ammonia feeder, which goes into this second part or into the vicinity of this second part located upstream.
[0009] A drawback of the known technical solution is the lack of a reactor cooling system, which can lead to an increase in ambient temperature, leading to the thermal decomposition of ammonium nitrate and subsequent explosion.
[0010] The objective of the claimed utility model and its technical result is to increase the safety of the process of obtaining ammonium nitrate, which is achieved by reducing the possibility (risk) of thermal decomposition of ammonium nitrate and the associated danger of explosion.
[0011] In order to solve the above problem and achieve the stated technical result, a tubular reactor for the production of ammonium nitrate is proposed, comprising: a chamber I for introducing reagents, to which a pipe A for feeding nitric acid and a pipe B for feeding ammonia are connected, a chamber II for mixing reagents, a chamber III for feeding additional components, to which a pipe C is connected for additional feeding of ammonia, an outlet chamber IV, characterized in that a pipe D for feeding a cooling solution is connected to chamber III for feeding additional components.
[0012] A cooling solution is a solution that allows the temperature of the reaction mixture in the mixing chamber to be reduced, for example, water or an aqueous solution of ammonium nitrate having a mass concentration lower than the concentration of the ammonium nitrate solution at the outlet of the outlet chamber.
[0013] A chamber is a hollow space bounded by a lateral surface (e.g., a cylindrical shape (circular, elliptical, etc.)). Typically, a chamber has at least one inlet and outlet.
[0014] A branch pipe is a small piece of pipe connected to a tank (chamber).
[0015] Ammonia supplementation refers to the addition of additional ammonia to the tubular reactor to improve the dosing accuracy of the starting components and achieve an optimal pH value for the reaction mixture. The aforementioned design of the tubular reactor, along with the presence of a D-port for supplying a cooling solution, allows for the addition of a cooling solution to the reactor and, by evaporating the water introduced with the solution, maintains a stable temperature in the reactor, thereby reducing the risk of thermal decomposition of ammonium nitrate and subsequent explosion.
[0016] The above combination of features is sufficient to achieve the stated technical result. Furthermore, the following features, inherent in specific embodiments, enable the stated technical result to be achieved most effectively and further reduce the risk of thermal decomposition of ammonium nitrate and subsequent explosion.
[0017] In a preferred embodiment, in the tubular reactor, the cooling solution is a recycled ammonium nitrate solution obtained during the purification stage of the juice vapor formed in the tubular reactor.
[0018] Juice steam refers to the steam formed by the evaporation of water from an ammonium nitrate solution.
[0019] The use of recycled ammonium nitrate solution, obtained during the purification stage of the juice steam generated in the tubular reactor, as a cooling solution ensures effective cooling of the reaction zone, maintaining the temperature at a safe level, which further reduces the possibility of thermal decomposition of ammonium nitrate and subsequent explosion.
[0020] In a preferred embodiment, in a tubular reactor, chamber III for feeding additional components contains means for distributing ammonia and a cooling solution.
[0021] The ammonia distributor (distributor) ensures a more uniform flow of ammonia into the reaction zone and efficient mixing of the components, thereby achieving optimal pH regulation within a safe range, which further reduces the risk of thermal decomposition of ammonium nitrate and explosion.
[0022] In a preferred embodiment, the means for distributing ammonia and cooling solution in a tubular reactor is an annular gap. The use of an annular gap allows ammonia and cooling solution to be evenly distributed throughout the reactant mixing chamber. This further helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0023] In a preferred embodiment, in a tubular reactor, an annular gap is located between the side surface of chamber III for feeding additional components and the side surface of chamber II for mixing reagents.
[0024] The above-mentioned annular gap arrangement allows ammonia and cooling solution to be evenly distributed throughout the reagent mixing chamber. This further helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0025] In a preferred embodiment, in a tubular reactor the width of the annular gap L g is in the range of 3-60 mm, preferably 5-50 mm.
[0026] The above-mentioned annular gap width is optimal for the most efficient distribution of ammonia and cooling solution, which further helps to reduce the possibility of thermal decomposition of ammonium nitrate and the occurrence of an explosion.
[0027] In a preferred embodiment, in a tubular reactor, the reactant mixing chamber II is located inside the chamber III for feeding additional components.
[0028] The above-mentioned mutual arrangement of the reagent mixing chamber and the chamber for feeding additional components ensures the presence of an annular gap with a width of L g for ammonia and cooling solution, which further helps reduce the possibility of thermal decomposition of ammonium nitrate and the occurrence of an explosion.
[0029] In a preferred embodiment, the tubular reactor has an additional chamber Ha for mixing reagents, located between chamber III for feeding additional components and the outlet chamber IV.
[0030] The additional reagent mixing chamber forms the optimal volume of the reaction zone, ensuring the completeness of the neutralization reaction, which additionally helps maintain the pH within a safe range, reduce the possibility of thermal decomposition of ammonium nitrate and explosion. In the preferred embodiment, in a tubular reactor, the ratio (z / A1b + b2a) of the length of chamber III for feeding additional components to the sum of the lengths of chamber II for mixing reagents and the additional chamber Pa for mixing reagents is in the range of 0.2-1.2, where z is the length of chamber III for feeding additional components, l is the length of chamber II for mixing reagents, and l is the length of the additional chamber Pa for mixing reagents.
[0031] The above ratio is optimal for effective mixing of the incoming media and complete neutralization reaction while maintaining a safe pH and temperature level, which further helps reduce the possibility of thermal decomposition of ammonium nitrate and the occurrence of an explosion.
[0032] In a preferred embodiment, in a tubular reactor, the branch pipe D for feeding the cooling solution has a tangential arrangement relative to the chamber III for feeding additional components.
[0033] This ensures the distribution of the gas-liquid flow and effective interaction of the incoming media, allowing them to be uniformly supplied to the reagent mixing chamber and ensuring temperature and pH control within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0034] In a preferred embodiment, in a tubular reactor, the angle a between the axis of the branch pipe D for supplying the cooling solution and the axis of the branch pipe C for additional supply of ammonia is 120-240°.
[0035] This ensures the distribution of the gas-liquid flow and effective interaction of the incoming media, allowing them to be uniformly supplied to the reagent mixing chamber and ensuring temperature and pH control within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0036] In a preferred embodiment, in a tubular reactor, the branch pipe C for additional supply of ammonia has a tangential arrangement relative to the chamber III for supplying additional components.
[0037] This ensures the distribution of the gas-liquid flow and effective interaction of the incoming media, allowing them to be uniformly supplied to the reagent mixing chamber and ensuring temperature and pH control within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0038] In a preferred embodiment, in a tubular reactor, the internal diameter ch of the reagent mixing chamber II is less than the internal diameter di of the reagent input chamber I.
[0039] This ensures an optimal level of flow turbulence in the mixing chamber, promoting more intense and efficient mass and heat transfer between the media. This maintains the temperature and pH within a safe range and further helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0040] In a preferred embodiment, in a tubular reactor, the internal diameter d2 of the reactant mixing chamber II is smaller than the internal diameter of the outlet chamber IV.
[0041] This ensures an optimal level of flow deceleration, creating vortices that intensify mass and heat transfer. This maintains the temperature and pH within a safe range and further helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0042] In a preferred embodiment, the tubular reactor has an expanding section at the inlet to the outlet chamber IV.
[0043] This ensures an optimal level of flow deceleration, creating vortices that intensify mass and heat transfer. This maintains the temperature and pH within a safe range and further helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0044] In a preferred embodiment, in a tubular reactor, the ratio dz / di of the internal diameters of the reagent mixing chamber II and the reagent input chamber I is in the range of 0.40-0.85.
[0045] This ensures an optimal level of flow turbulence in the mixing chamber, which facilitates more intense and efficient mass and heat transfer between the media. This also helps maintain temperature and pH within a safe range and reduces the risk of thermal decomposition of ammonium nitrate and explosion. In the preferred embodiment, in the tubular reactor, the cooling solution supply port D is located at a distance LD equal to 0.1 - 0.5L2 from the flange F connecting the reactant inlet chamber I and the reactant mixing chamber II, where LD is the length of the reactant mixing chamber II.
[0046] This ensures the distribution of the gas-liquid flow and effective interaction of the incoming media, allowing them to be uniformly supplied to the reagent mixing chamber and ensuring temperature and pH control within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0047] In a preferred embodiment, in a tubular reactor, the branch pipe C for additional supply of ammonia is located at a distance Lc equal to 0.1-0.51 l from the flange F connecting the chamber I for introducing reagents and the chamber II for mixing reagents, where 1 l is the length of the chamber II for mixing reagents.
[0048] This ensures the distribution of the gas-liquid flow and effective interaction of the incoming media, allowing them to be uniformly supplied to the reagent mixing chamber and ensuring temperature and pH control within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0049] In a preferred embodiment, in a tubular reactor the ratio (1l + 1la) / (12) of the sum of the length 1l of chamber II for mixing reagents and the length 1la of the additional chamber Pa for mixing reagents to the internal diameter ch of chamber II for mixing reagents is in the range of 7-20
[0050] This ratio ensures an optimal level of flow turbulence in the mixing chamber, which promotes more intense and efficient mass and heat transfer between the media and creates an optimal reaction zone volume to ensure the complete neutralization reaction. This also helps maintain the temperature and pH within a safe range and helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0051] In the preferred embodiment, the tubular reactor's nitric acid inlet A is equipped with a converging section. The converging section of the nitric acid inlet increases the flow velocity. This high velocity helps further turbulent the mixing process due to the kinetic energy of the nitric acid stream entering the mixing chamber, which promotes more efficient reaction and helps maintain the temperature and pH within a safe range. This also helps reduce the risk of thermal decomposition of ammonium nitrate and explosion.
[0052] Brief description of the drawings
[0053] The drawings are presented for a better understanding of the utility model, however, it will be obvious to a person skilled in the art that the disclosed utility model is not limited to the variant shown in them.
[0054] Fig. 1 shows a schematic representation of a tubular reactor according to the present utility model.
[0055] Fig. 2 shows a cross-section of a tubular reactor, reflecting the relative position of the pipe C for additional supply of ammonia and the pipe D for supplying the cooling solution.
[0056] All figures show diagrams and are not drawings.
[0057] Designations:
[0058] I - reagent input chamber,
[0059] II - reagent mixing chamber,
[0060] Pa - additional reagent mixing chamber,
[0061] III - chamber for feeding additional components,
[0062] IV - outlet chamber,
[0063] A - branch pipe for supplying nitric acid,
[0064] B - ammonia supply pipe,
[0065] C - branch pipe for additional supply of ammonia,
[0066] D - branch pipe for supplying cooling solution,
[0067] F is the flange connecting chamber I for the reagent input and chamber II for mixing reagents, di is the inner diameter of the reagent input chamber, dz is the inner diameter of the reagent mixing chamber,
[0068] L2 - length of the reagent mixing chamber,
[0069] Ьга – length of additional reagent mixing chamber, з – length of chamber for feeding additional components,
[0070] Lc is the distance from the flange F to the branch pipe C,
[0071] LD - distance from flange F to branch pipe D,
[0072] L g - the width of the annular gap, a - the angle between the axis of the branch pipe D and the axis of the branch pipe C.
[0073] Implementation of a utility model
[0074] The described embodiment examples are provided for illustrative purposes only. Those skilled in the art will readily recognize that other embodiments are possible without altering the essence of the utility model.
[0075] All units of the claimed device are interconnected by assembly operations and are in functional and structural unity.
[0076] Fig. 1 shows a schematic representation of a tubular reactor.
[0077] The tubular reactor contains a chamber I for introducing reagents, a chamber II for mixing reagents, an additional chamber Pa for mixing reagents, a chamber III for feeding additional components, and an outlet chamber IV.
[0078] Chamber I for introducing reagents has an internal diameter di and is connected to an axial pipe A for feeding nitric acid and a tangential pipe B for feeding ammonia.
[0079] Chamber II for mixing reagents has an internal diameter d2 and a length r. At the entrance to chamber II for mixing reagents there is a narrowing section.
[0080] Chamber III for feeding additional components has a length of z and is connected to a tangential pipe C for feeding additional ammonia and a tangential pipe D for feeding a cooling solution. Chamber II for mixing reagents is located inside chamber III for feeding additional components. Between the side surface of chamber II for mixing reagents and the side surface of chamber III for feeding additional components, there is an annular gap of width L for distributing ammonia and the ammonium nitrate cooling solution. g .
[0081] Pipe C is located at a distance Lc from flange F, which connects chamber I for introducing reagents and chamber II for mixing reagents. Pipe D is located at a distance LD from flange F. The angle between the axis of pipe D and the axis of pipe C is a (see Fig. 2).
[0082] Between the reagent mixing chamber II and the outlet chamber IV, there is an additional mixing chamber Pa with a length of 1 a. An expanding section is installed at the entrance to the outlet chamber IV.
[0083] The reactor chambers are connected to each other by flanges and welding. Pipes A, B, C, and D are welded into the reactor vessel.
[0084] The claimed device operates as follows.
[0085] A stream of nitric acid with a concentration of 45-60% by weight and a temperature of 35-80°C is introduced into chamber I, where the reactants are injected, through port A. A gaseous stream of ammonia at a temperature of 100-125°C is introduced through port B. The ratio between the nitric acid and ammonia flows is close to stoichiometric. In chamber II, where the reactants are mixed, the nitric acid solution is mixed with gaseous ammonia, and a neutralization reaction occurs, forming an ammonium nitrate solution and releasing a large amount of heat. The heat of the exothermic reaction increases the temperature of the ammonium nitrate solution and produces juice vapor.
[0086] Next, additional ammonia is introduced through port C to more accurately maintain the required nitric acid to ammonia flow ratio and ensure the neutralization reaction proceeds completely. The amount of ammonia introduced through port C is regulated so that the juice vapor released during the neutralization reaction in regent mixing chamber II has a base pH of 8.5-9.5.
[0087] Next, at a temperature of 175-185 °C, an aqueous solution of ammonium nitrate with a concentration of 75-82 wt.% and juice steam from reagent mixing chamber II are sent to an additional reagent mixing chamber Ila, and then to the outlet chamber IV of the tubular reactor and then to the separator.
[0088] The outlet temperature of the tubular reactor is maintained at a level not exceeding 190°C by automatically regulating the flow of recirculated ammonium nitrate solution 5. A cooling ammonium nitrate solution with a concentration of 15-35% by weight, obtained during the purification of the juice vapor generated in the tubular reactor, is fed through pipe D into the reactant mixing chamber II of the tubular reactor. Thus, the recirculated ammonium nitrate solution cools the reaction mixture by evaporating the water supplied with the incoming solution and reduces the possibility of thermal decomposition of ammonium nitrate and the associated explosion hazard.
[0089] The test results of the claimed device are presented in the table below.
[0090] Table 1
[0091]
[0092] Thus, the claimed device ensures an increase in the safety of the process of obtaining ammonium nitrate, which is achieved by reducing the possibility (risk) of thermal decomposition of ammonium nitrate and the associated danger of explosion.
Claims
Utility model formula 1. A tubular reactor for the production of ammonium nitrate, comprising: a chamber I for introducing reagents, to which a pipe A for feeding nitric acid and a pipe B for feeding ammonia are connected, a chamber II for mixing reagents, a chamber III for feeding additional components, to which a pipe C for additionally feeding ammonia is connected, an outlet chamber IV, characterized in that a pipe D for feeding a cooling solution is connected to chamber III for feeding additional components.
2. A tubular reactor according to claim 1, wherein the cooling solution is a recirculated ammonium nitrate solution obtained at the stage of purifying the juice vapor formed in the tubular reactor.
3. A tubular reactor according to claim 1, in which chamber III for feeding additional components contains means for distributing ammonia and a cooling solution.
4. A tubular reactor according to paragraph 3, in which the means for distributing ammonia and cooling solution is an annular gap.
5. A tubular reactor according to I.4, in which the annular gap is located between the side surface of chamber III for feeding additional components and the side surface of chamber II for mixing reagents.
6. A tubular reactor according to claim 5, in which the width of the annular gap L g is in the range of 3-60 mm, preferably 5-50 mm.
7. A tubular reactor according to claim 1, in which the reactant mixing chamber II is located inside the chamber III for feeding additional components.
8. A tubular reactor according to claim 1, in which there is an additional chamber Pa for mixing reagents, located between chamber III for feeding additional components and the outlet chamber IV.
9. A tubular reactor according to item 8, in which the ratio (zDT + bga) of the length of chamber III for feeding additional components to the sum of the lengths of chamber II for mixing reagents and the additional chamber Pa for mixing reagents is in the range of 0.2-1.2, where z is the length of chamber III for feeding additional components, L2 is the length of chamber II for mixing reagents, ha is the length of the additional chamber Pa for mixing reagents.
10. A tubular reactor according to claim 1, in which the branch pipe D for feeding the cooling solution has a tangential arrangement relative to the chamber III for feeding additional components.
11. A tubular reactor according to claim 1, in which the angle a between the axis of the branch pipe D for supplying the cooling solution and the axis of the branch pipe C for additional supply of ammonia is 120-240°.
12. A tubular reactor according to claim 1, in which the branch pipe C for additional supply of ammonia has a tangential arrangement relative to the chamber III for supplying additional components.
13. A tubular reactor according to claim 1, in which the internal diameter d2 of the reagent mixing chamber II is less than the internal diameter di of the reagent input chamber I.
14. A tubular reactor according to claim 1, in which the internal diameter d2 of the reagent mixing chamber II is smaller than the internal diameter of the outlet chamber IV.
15. A tubular reactor according to claim 1, in which there is an expanding section at the inlet to the outlet chamber IV.
16. A tubular reactor according to claim 1, in which the ratio d2 / di of the internal diameters of the reagent mixing chamber II and the reagent input chamber I is in the range of 0.40-0.
85.
17. A tubular reactor according to claim 1, in which the branch pipe D for feeding the cooling solution is located at a distance LD equal to 0.1-0.51 from the flange F connecting the chamber I for introducing the reactants and the chamber II for mixing the reactants, where L2 is the length of the chamber II for mixing the reactants.
18. A tubular reactor according to claim 1, in which the branch pipe C for additional supply of ammonia is located at a distance Lc equal to 0.1-0.5L2 from the flange F connecting the chamber I for introducing reagents and the chamber II for mixing reagents, where L2 is the length of the chamber II for mixing reagents.
19. A tubular reactor according to claim 8, in which the ratio (L2 + L2a) / d2 of the sum of the length L2 of chamber II for mixing reagents and the length ha of the additional chamber Ha for mixing reagents to the internal diameter d2 of chamber II for mixing reagents is in the range of 7-20.
20. A tubular reactor according to claim 1, in which the pipe A for feeding nitric acid is equipped with a tapering section.