A waste heat recovery device for urea hydrolysis heating steam condensation

Abstract

The application discloses a urea hydrolysis heating steam and water drain waste heat recovery device, which comprises a waste heat recovery mechanism, a hydrolysis reaction part, a first recovery part arranged on the hydrolysis reaction part, a second recovery part arranged on the first recovery part, a booster part arranged on the first recovery part and an auxiliary heating part arranged on the second recovery part. The urea hydrolysis heating steam and water drain waste heat recovery device can recover the hydrolysis heater steam and water drain and the secondary air heater water drain for preheating cold dilution air, can save the secondary air heater auxiliary steam consumption and can reduce the operation cost of the unit. The urea hydrolysis system is provided with a first air heater for preheating cold dilution air, the heat source is steam and water drain, the dilution air temperature entering the secondary air heater is increased, the auxiliary steam consumption is reduced, the operation economy of the unit is improved, and the steam discharge tank can be prevented from discharging steam after the water drain waste heat is recovered and utilized.

Description

Technical Field

[0001] This invention relates to the technical field of urea hydrolysis, and more particularly to a waste heat recovery device for urea hydrolysis heating steam. Background Technology

[0002] Urea hydrolysis typically involves injecting a urea solution with a mass concentration of approximately 50% into a hydrolysis reactor, heating it to a certain temperature and pressure, and then hydrolyzing it to produce NH3, CO2, and water vapor. The product gas generated by hydrolysis enters an ammonia-air mixer, mixes with hot dilution air, and is then sent to an ammonia injection grid. The hot dilution air can be obtained by heating cold dilution air using a steam heater.

[0003] The heating of the urea hydrolysis reactor is usually achieved by using high-temperature and high-pressure steam from the power plant, which is then converted into heating steam at 180°C and 1MPa through a desuperheating and depressurization device. This method consumes a large amount of steam, and the steam condensate temperature is about 95°C. Directly collecting the steam into the condensate tank will cause steam leakage, and the heat from the condensate cannot be effectively recovered and utilized. In addition, the hot dilution air in the boiler area can be obtained by heating the cold dilution air using a steam heater. The heat source for the heater is the auxiliary steam of the unit. After heating, the heater will also generate a large amount of high-temperature condensate. If the heat from the condensate in both of these parts can be recovered and utilized, it will generate considerable economic benefits. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned urea hydrolysis heating steam hydrophobic waste heat recovery device, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a waste heat recovery device for urea hydrolysis heating steam condensate, which aims to recover and utilize the heat from the steam condensate and the high-temperature condensate generated by the heater.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0007] The waste heat recovery mechanism includes a hydrolysis reaction section, a primary recovery section disposed on the hydrolysis reaction section, a secondary recovery section disposed on the primary recovery section, a pressurization section disposed on the primary recovery section, an auxiliary heating section disposed on the secondary recovery section, a hot air section disposed on the secondary recovery section, and a mixing section disposed on the hot air section.

[0008] The heating mechanism includes a hydrolysis section disposed between the hydrolysis reaction section and the mixing section, and a heating section disposed on the hydrolysis reaction section.

[0009] As a preferred embodiment of the urea hydrolysis heating steam condensate waste heat recovery device of the present invention, the hydrolysis reaction section includes a hydrolysis reactor, a coil disposed in the hydrolysis reactor, and a steam condensate pipe disposed on the coil, with one end of the coil connected to one end of the steam condensate pipe.

[0010] As a preferred embodiment of the urea hydrolysis heating steam condensate waste heat recovery device of the present invention, the primary recovery unit includes a primary recovery pipe disposed on the steam condensate pipe, a primary air heater disposed on the primary recovery pipe, a cold dilution air duct disposed on the primary air heater, and a drain pipe disposed on the primary air heater. One end of the primary recovery pipe is connected to the other end of the steam condensate pipe, and the other end of the primary recovery pipe is connected to the water inlet of the primary air heater. One end of the cold dilution air duct is connected to the air inlet of the primary air heater, and one end of the drain pipe is connected to the water outlet of the primary air heater.

[0011] As a preferred embodiment of the urea hydrolysis heating steam condensate waste heat recovery device of the present invention, the secondary recovery unit includes a secondary air heater, a waste heat air duct disposed between the secondary air heater and the primary air heater, one end of the waste heat air duct being connected to the air outlet of the primary air heater, the other end of the waste heat air duct being connected to the air inlet of the secondary air heater, a secondary recovery pipe disposed between the steam condensate pipe and the secondary air heater, the secondary recovery pipe being connected to the steam condensate pipe via a three-way valve, and one end of the secondary recovery pipe being connected to the water outlet of the secondary air heater.

[0012] As a preferred embodiment of the urea hydrolysis heating steam condensate waste heat recovery device of the present invention, the pressurization unit includes a check valve disposed on the steam condensate pipe and a booster pump disposed on the primary recovery pipe, wherein the output end of the booster pump is connected to the water inlet end of the primary heater through the primary recovery pipe.

[0013] As a preferred embodiment of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention, the auxiliary heating section includes an auxiliary steam pipe disposed on the secondary air heater, an auxiliary steam flow meter disposed on the auxiliary steam pipe, and an auxiliary steam regulating valve disposed on the auxiliary steam pipe.

[0014] As a preferred embodiment of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention, the hot air section includes a hot dilution air duct disposed on the secondary air heater, a hot air pressure gauge disposed on the hot dilution air duct, a hot air temperature gauge disposed on the hot dilution air duct, and a hot air flow meter disposed on the hot dilution air duct.

[0015] As a preferred embodiment of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention, the mixing section includes an ammonia-air mixer disposed on the hot dilution air duct and a denitrification reaction tube disposed on the ammonia-air mixer.

[0016] As a preferred embodiment of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention, the hydrolysis section includes a hydrolysis pipe disposed on the hydrolysis reactor and connected to the ammonia-air mixer, a hydrolysis regulating valve disposed on the hydrolysis pipe, and a hydrolysis flow meter disposed on the hydrolysis pipe.

[0017] As a preferred embodiment of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention, the heating section includes a desuperheating and pressure reducing steam pipe, one end of which is connected to the air inlet of the coil, a steam pressure gauge, a steam temperature gauge, a steam regulating valve, a steam flow meter, and two steam ball valves.

[0018] The beneficial effects of this invention are: by recycling the condensate from the hydrolyzer heating steam and the condensate from the secondary heater for preheating the cold dilution air, the consumption of auxiliary steam for the secondary heater can be reduced, thus lowering the operating cost of the unit.

[0019] The urea hydrolysis system adds a primary air heater for preheating cold dilution air. The heat source is steam condensate, which increases the temperature of the dilution air entering the secondary air heater, reduces auxiliary steam consumption, and improves the economic efficiency of unit operation. After the waste heat from the condensate is recovered and utilized, the temperature decreases, which can eliminate the steam leakage phenomenon in the condensate tank. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0021] Figure 1 This is a schematic diagram of the overall structure of the urea hydrolysis heating steam hydrophobic waste heat recovery device of the present invention. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0026] Example 1

[0027] Reference Figure 1 This is the first embodiment of the present invention, which provides a waste heat recovery device for urea hydrolysis heating steam, the device comprising,

[0028] The waste heat recovery mechanism 100 includes a hydrolysis reaction section 101, a primary recovery section 102 disposed on the hydrolysis reaction section 101, a secondary recovery section 103 disposed on the primary recovery section 102, a pressurization section 104 disposed on the primary recovery section 102, an auxiliary heating section 105 disposed on the secondary recovery section 103, a hot air section 106 disposed on the secondary recovery section 103, and a mixing section 107 disposed on the hot air section 106.

[0029] The heating mechanism 200 includes a hydrolysis section 201 disposed between the hydrolysis reaction section 101 and the mixing section 107, and a heating section 202 disposed on the hydrolysis reaction section 101.

[0030] During use, a urea solution with a mass concentration of about 50% is injected into the hydrolysis reaction section 101. The product gas generated by the hydrolysis in the hydrolysis reaction section 101 enters the mixing section 107 and is mixed with the hot dilution air before being sent to the ammonia injection grid. The cold dilution air is preheated by the primary recovery section 102 and then enters the secondary recovery section 103. Finally, it enters the mixing section 107 through the hot air section 106. The steam condensate from the hydrolysis reaction section 101 and the secondary recovery section 103 is collected and pressurized by the pressurization section 104 before entering the primary recovery section 102. The condensate from the outlet of the primary recovery section 102 is recovered to the condensate tank.

[0031] Example 2

[0032] Reference Figure 1This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the hydrolysis reaction section 101 includes a hydrolysis reactor 101a, a coil 101b disposed in the hydrolysis reactor 101a, and a steam trap 101c disposed on the coil 101b. One end of the coil 101b is connected to one end of the steam trap 101c.

[0033] Preferably, the hydrolysis reactor 101a is responsible for heating the urea solution to a certain temperature and pressure to promote the hydrolysis reaction of urea and generate NH3, CO2 and water vapor. The coil 101b is used to heat or cool the urea solution to maintain the temperature required for the hydrolysis reaction.

[0034] The primary recovery unit 102 includes a primary recovery pipe 102d installed on a steam trap 101c, a primary air heater 102a installed on the primary recovery pipe 102d, a cold dilution air duct 102b installed on the primary air heater 102a, and a drain pipe 102c installed on the primary air heater 102a. One end of the primary recovery pipe 102d is connected to the other end of the steam trap 101c, and the other end of the primary recovery pipe 102d is connected to the water inlet of the primary air heater 102a. One end of the cold dilution air duct 102b is connected to the air inlet of the primary air heater 102a, and one end of the drain pipe 102c is connected to the water outlet of the primary air heater 102a.

[0035] Preferably, adding a primary heater 102a can improve the heat exchange efficiency of the entire system and reduce energy waste. In addition, the addition of the primary heater 102a may also help reduce the start-up time and preheating cycle of the equipment, and improve the response speed and flexibility of the device.

[0036] Furthermore, by adding a primary air heater 102a and using steam condensate as a heat source, the temperature of the dilution air entering the secondary air heater 103b can be increased. The denitrification dilution air is preheated by using urea hydrolysis to heat the steam condensate. This process not only reduces the need for an additional heat source, but also increases the temperature of the dilution air entering the secondary air heater 103b, which helps to reduce the auxiliary steam consumption of the secondary air heater 103b, thereby reducing energy consumption and operating costs.

[0037] Furthermore, by recovering waste heat, the temperature of the condensate is reduced, which helps to reduce energy waste and environmental problems. Through effective waste heat recovery, the temperature of the condensate is reduced after it is utilized, thereby reducing steam leakage in the condensate tank. This not only reduces energy waste but also reduces environmental impact and reduces the safety risks that may be caused by high-temperature condensate.

[0038] Furthermore, the reduced temperature of the hydrophobic material after utilization can decrease evaporation in the hydrophobic tank. Heat transfer: In waste heat recovery systems, the hydrophobic material is used to preheat other media, such as cold dilution air. During this process, the heat in the hydrophobic material is transferred to other media, causing the hydrophobic material itself to cool down. Reduced evaporation: As the hydrophobic temperature decreases, its evaporation rate decreases. High-temperature water evaporates more easily, producing steam, but as the temperature decreases, evaporation decreases, thus reducing evaporation in the hydrophobic tank. Thermal energy reuse: Through waste heat recovery, the thermal energy in the hydrophobic material is effectively utilized instead of simply being released into the environment. This reduces thermal energy waste and lowers the amount of thermal energy carried by the hydrophobic material, further reducing evaporation. Reduced thermal pollution: The reduced temperature of the hydrophobic material reduces thermal pollution to the surrounding environment when released into the environment, helping to maintain environmental temperature balance. Reduced greenhouse gas emissions: The reduced temperature of the hydrophobic material may reduce water vapor released into the atmosphere due to evaporation, helping to reduce the greenhouse effect.

[0039] Furthermore, high-temperature hydrophobic condensate may cause burns when it comes into contact with personnel; this risk is significantly reduced as the temperature decreases. Prolonged exposure to high-temperature hydrophobic condensate may lead to aging and damage to equipment and piping materials, increasing maintenance costs and safety risks. Reducing the amount of hydrophobic condensate can extend the lifespan of the equipment. High-temperature hydrophobic condensate may accelerate the corrosion process of certain materials, reducing equipment lifespan and safety. The presence of high-temperature hydrophobic condensate may require additional safety measures, such as thermal insulation, which may increase operational complexity and costs. Lowering the temperature can reduce operational complexity and costs. Through effective waste heat recovery, not only can energy waste and environmental impact be reduced, but the safety risks that may be caused by high-temperature hydrophobic condensate can also be reduced, improving the safety and sustainability of the entire system.

[0040] The secondary recovery unit 103 includes a secondary air heater 103b, a waste heat air duct 103c disposed between the secondary air heater 103b and the primary air heater 102a, one end of the waste heat air duct 103c being connected to the air outlet of the primary air heater 102a, the other end of the waste heat air duct 103c being connected to the air inlet of the secondary air heater 103b, a secondary recovery pipe 103a disposed between the steam trap pipe 101c and the secondary air heater 103b, the secondary recovery pipe 103a being connected to the steam trap pipe 101c via a three-way valve, and one end of the secondary recovery pipe 103a being connected to the water outlet of the secondary air heater 103b.

[0041] Preferably, the urea hydrolysis heating steam condensate and the steam condensate from the secondary heater 103b are uniformly recycled and reused. This takes into account the waste heat that may be generated during the entire urea hydrolysis process and uses it to preheat the cold dilution air. By simultaneously recycling the urea hydrolysis heating steam condensate and the condensate generated by the secondary heater 103b, comprehensive waste heat recovery is achieved, which not only improves energy utilization efficiency but also reduces energy waste and helps to lower the overall energy cost.

[0042] Furthermore, heating requirements are reduced: by preheating the cold dilution air using the primary air heater 102a, the air temperature entering the secondary air heater 103b is increased. This means that the secondary air heater 103b does not need to consume excessive steam to reach the required temperature, thus reducing the steam flow through it. Steam distribution is optimized: after reducing the steam demand of the secondary air heater 103b, steam resources can be reallocated, allocating more steam to the hydrolysis reactor 101a. This increases the steam supply to the hydrolysis reactor 101a, thereby improving steam flow efficiency. The reaction temperature is increased: more steam is used for the hydrolysis reaction... The presence of a heat exchanger 101a may increase the temperature inside the hydrolysis reactor 101a, thereby accelerating the hydrolysis reaction rate of urea and improving the efficiency of the entire hydrolysis process. It also reduces heat loss: when the preheated dilution air enters the secondary air heater 103b, the required heating amount is reduced, thus reducing the heat loss of the secondary air heater 103b. This can improve the thermal efficiency of the entire system and indirectly improve the operating efficiency of the hydrolysis reactor 101a. Therefore, utilizing the waste heat from the hydrophobic layer not only saves on the auxiliary steam consumption of the secondary air heater 103b but also improves the steam flow efficiency of the hydrolysis reactor 101a, contributing to the economy and efficiency of the entire urea hydrolysis system.

[0043] Both the primary air heater 102a and the secondary air heater 103b use 316L stainless steel plate heat exchangers.

[0044] Preferably, since urea solution is involved, the material of the heat exchanger needs to have good corrosion resistance to prevent chemical corrosion. At the same time, the heat exchanger needs to have high thermal efficiency in order to effectively recover heat from the phlegm. 316L stainless steel contains molybdenum, which provides higher corrosion resistance than ordinary stainless steel and is suitable for handling potentially corrosive fluids such as urea solution. Plate heat exchangers are known for their high thermal efficiency, and their compact design allows for a larger heat exchange area in a smaller space, which helps to improve the efficiency of heat recovery.

[0045] The booster unit 104 includes a check valve 104a installed on the steam trap 101c and a booster pump 104b installed on the primary recovery pipe 102d. The output end of the booster pump 104b is connected to the inlet end of the primary heater 102a through the primary recovery pipe 102d.

[0046] Preferably, by using the check valve 104a and the secondary recovery pipe 103a, auxiliary gas can be used to backflush the primary heater 102a and the secondary heater 103b to remove deposits or blockages inside the primary heater 102a and the secondary heater 103b. The check valve 104a is used to prevent fluid from flowing backward. During the cleaning process, the check valve can ensure that steam does not enter areas that should not be cleaned.

[0047] Furthermore, the check valve 104a ensures unidirectional flow of steam or gas, prevents possible backflow, and protects system safety. The use of the check valve 104a improves system safety, prevents equipment damage or operational accidents that may be caused by backflow, and also helps reduce pressure fluctuations in the system and maintain a stable operating environment.

[0048] Furthermore, by using a booster pump 104b to collect the two types of condensate and introduce them into a primary air heater 102a for preheating the cold dilution air, not only is thermal efficiency improved, but dependence on external heat sources is also reduced. At the same time, thermal pollution to the environment is reduced because the recycled condensate reduces the amount of heat directly emitted into the environment. This also reduces the need for external heat sources, which helps to reduce overall energy consumption and operating costs.

[0049] Furthermore, the use of booster pump 104b ensures that the condensate can be effectively transported and utilized, improving the system's operating efficiency. Through booster pump 104b, the condensate can be effectively collected and transported to the primary heater 102a. This step not only ensures that the condensate is fully utilized but also improves the thermal efficiency and stability of the entire device. The use of booster pump 104b has the following effects: Increased condensate pressure: Booster pump 104b can increase the condensate pressure, allowing the originally low-pressure condensate to be effectively transported to where it is needed. Since the pressure of the condensate usually decreases after releasing heat, without booster pump 104b, this low-pressure condensate may not be able to be transported over long distances or circulate within the device; Ensured continuous flow: Booster pump 104b ensures continuous flow of condensate in the system, which is crucial for maintaining the continuous operation of the entire waste heat recovery system. Continuous flow helps maintain the stability and efficiency of the device. Optimized heat exchange: Through the booster pump 104b, the condensate can enter the primary air heater 102a at a higher pressure and flow rate, which improves heat exchange efficiency. The faster flow rate means a shorter heat exchange time, thereby reducing heat loss and improving the utilization efficiency of thermal energy. Maximized heat utilization: The use of the booster pump 104b allows for precise control of the condensate flow rate and pressure, thereby optimizing the heat exchange process and maximizing heat utilization. This control capability is crucial for improving the overall thermal efficiency of the device. Reduced heat loss: Since the booster pump 104b can maintain the flow and pressure of the condensate, it can reduce heat loss in the system. Maintaining the condensate flow at a higher pressure can reduce heat loss due to pressure drop. Improved system reliability: The use of the booster pump 104b improves the reliability of the device because it ensures that the condensate can be effectively transported and utilized even under different operating conditions. This reliability is crucial for ensuring the long-term stable operation of the device; Environmental adaptability: Booster pump 104b can adapt to different environmental conditions and operating requirements, enabling the system to operate efficiently under various conditions, whether under high or low back pressure; Flexibility and expandability: Booster pump 104b provides flexibility to the device, allowing adjustment of the condensate flow rate and pressure according to actual needs to adapt to different operating conditions or future system expansion; In these ways, the use of booster pump 104b not only ensures that the condensate can be fully utilized, but also improves the thermal efficiency and stability of the entire system.

[0050]

[0051]

[0052] The SPI is calculated as follows, taking into account factors such as heat recovery rate, preheating efficiency, system energy consumption, and condensate flow rate:

[0053]

[0054] k and d are constants determined according to the experimental design;

[0055] A is the working pressure of the booster pump.

[0056] According to the table above, the SPI index reaches its peak when the booster pump's operating pressure A is 1.9 MPa, indicating that the waste heat recovery system performs best at this operating pressure.

[0057] The auxiliary heating unit 105 includes an auxiliary steam pipe 105a installed on the secondary air heater 103b, an auxiliary steam flow meter 105b installed on the auxiliary steam pipe 105a, and an auxiliary steam regulating valve 105c installed on the auxiliary steam pipe 105a.

[0058] Preferably, the temperature of the urea hydrolysis product gas is generally between 130 and 160°C, and the temperature of the hot dilution air is usually not lower than 140°C. The auxiliary steam flow rate can be adjusted in real time using the auxiliary steam regulating valve 105c to ensure that the temperature of the hot dilution air meets the standard.

[0059] Preferably, by setting up the auxiliary steam flow meter 105b and the auxiliary steam regulating valve 105c, the device has the ability to dynamically adjust the auxiliary steam flow to adapt to different operating conditions, ensure that the temperature of the hot dilution air meets the requirements, and can dynamically adjust the auxiliary steam flow according to real-time monitoring data to ensure that the temperature of the hot dilution air is always kept within the optimal operating range. This intelligent adjustment mechanism improves the system's response speed and control accuracy, and helps to maintain the stability and efficiency of the urea hydrolysis process.

[0060] Furthermore, by dynamically adjusting the auxiliary steam flow rate, the device can ensure that the temperature of the hot dilution air is always kept within the optimal operating range, which is crucial for the efficiency of the urea hydrolysis reaction and the selectivity of the products.

[0061] By precisely controlling the auxiliary steam flow, the system can avoid unnecessary energy waste and achieve more economical operation;

[0062] Maintaining the operating temperature within the optimal range can reduce the environmental impact caused by excessively high or low temperatures, such as reducing heat loss and preventing the formation of harmful byproducts.

[0063] Enhanced operational flexibility: The intelligent adjustment mechanism provides operational flexibility, allowing operators to quickly adjust operating parameters according to actual needs to cope with various situations that may occur during the production process;

[0064] The auxiliary steam flow rate is dynamically adjusted based on real-time monitoring data, and the intelligent adjustment mechanism helps maintain the stability and efficiency of the urea hydrolysis process.

[0065] The hot air section 106 includes a heat dilution air duct 106a installed on the secondary air heater 103b, a hot air pressure gauge 106b installed on the heat dilution air duct 106a, a hot air temperature gauge 106c installed on the heat dilution air duct 106a, and a hot air flow meter 106d installed on the heat dilution air duct 106a.

[0066] The mixing section 107 includes an ammonia-air mixer 107a disposed on a hot dilution air duct 106a, and a denitrification reaction pipe 107b disposed on the ammonia-air mixer 107a.

[0067] Preferably, the NH3, CO2 and water vapor generated by hydrolysis are mixed with hot dilution air and then enter the ammonia-air mixer 107a, ready to be sent to the denitrification reactor.

[0068] The remaining structure is the same as that in Example 1.

[0069] During operation, a urea solution with a mass concentration of approximately 50% is injected into the hydrolysis reactor 101a. The product gas generated by the hydrolysis in the hydrolysis reactor 101a enters the ammonia-air mixer 107a through the hydrolysis section 201. The steam condensate in the hydrolysis reactor 101a enters the primary air heater 102a through the steam condensate pipe 101c and the primary recovery pipe 102d. The steam condensate in the primary air heater 102a heats the cold dilution air in the cold dilution air pipe 102b, while the cold dilution air cools the steam condensate. The cooled steam condensate enters the condensate drain tank through the drain pipe 102c. The preliminarily heated cold dilution air passes through the waste heat air pipe 103c. Entering the secondary air heater 103b, auxiliary steam further heats the cold dilution air through auxiliary steam pipe 105a, thereby heating the cold dilution air to the standard hot dilution air. At the same time, the condensate from the secondary air heater 103b enters the primary recovery pipe 102d through the secondary recovery pipe 103a. The booster pump 104b is started to pressurize the steam condensate and the condensate from the secondary air heater 103b to a certain water pressure and deliver them to the primary air heater 102a, thereby recovering the waste heat of the condensate from the secondary air heater 103b. The hot dilution air enters the ammonia-air mixer 107a through the hot dilution air pipe 106a. The ammonia-air mixer 107a mixes the hot dilution air and the hydrolysis product gas and then sends it into the ammonia injection grille.

[0070] Example 3

[0071] Reference Figure 1 This is the third embodiment of the present invention. The difference between this embodiment and the second embodiment is that the hydrolysis section 201 includes a hydrolysis pipe 201a disposed on the hydrolysis reactor 101a and connected to the ammonia-air mixer 107a, a hydrolysis regulating valve 201b disposed on the hydrolysis pipe 201a, and a hydrolysis flow meter 201c disposed on the hydrolysis pipe 201a.

[0072] Preferably, the hydrolysis regulating valve 201b is used to control the flow rate of gases such as ammonia produced after hydrolysis to meet the needs of the denitrification reactor or other downstream equipment, and the hydrolysis flow meter 201c is used to ensure the accuracy and consistency of gas supply.

[0073] The heating unit 202 includes a desuperheating and pressure reducing steam pipe 202a, one end of which is connected to the air inlet of the coil 101b. A steam pressure gauge 202b, a steam temperature gauge 202c, a steam regulating valve 202d, a steam flow meter 202e, and two steam ball valves 202f are installed on the desuperheating and pressure reducing steam pipe 202a.

[0074] Preferably, two steam ball valves 202f are provided, serving as dual regulating valves to provide finer control and ensure that the temperature and pressure of the steam are within a stricter range. The two steam ball valves 202f can provide system redundancy; if one regulating valve fails, the other can serve as a backup, ensuring continuous system operation. When maintenance or repair is required on one steam ball valve 202f, the other can remain operational, reducing system downtime. The steam ball valve 202f provides a tight shut-off mechanism to prevent high-temperature steam leakage, while also being able to withstand the high temperature and pressure of the steam.

[0075] Preferably, the steam regulating valve 202d focuses on precisely controlling the temperature and pressure of steam to meet the needs of subsequent processes, while the steam flow meter 202e monitors the steam flow rate to ensure that the system provides adequate heat energy.

[0076] The remaining structure is the same as that in Example 2.

[0077] During operation, the hydrolysis product gas generated by heating and hydrolysis in the hydrolysis reactor 101a enters the ammonia-air mixer 107a through the hydrolysis pipe 201a. The flow rate of the hydrolysis product gas into the ammonia-air mixer 107a is controlled by the hydrolysis regulating valve 201b. The steam ball valve 202f on the desuperheating and pressure reducing steam pipe 202a leading to the hydrolysis reactor 101a is opened. The steam pressure gauge 202b and steam temperature gauge 202c are observed to detect the steam temperature and pressure. The steam temperature and pressure are adjusted by the steam regulating valve 202d to ensure that they reach the specific parameters required for the hydrolysis reaction. The steam flow path in the coil 101b is opened, and the desuperheating and pressure reducing steam is used to preheat the hydrolysis reactor to achieve a suitable reaction temperature.

[0078] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0079] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0080] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A waste heat recovery device for urea hydrolysis heating steam, characterized in that: include, Waste heat recovery mechanism (100) includes a hydrolysis reaction section (101), a primary recovery section (102) disposed on the hydrolysis reaction section (101), a secondary recovery section (103) disposed on the primary recovery section (102), a pressurization section (104) disposed on the primary recovery section (102), an auxiliary heating section (105) disposed on the secondary recovery section (103), a hot air section (106) disposed on the secondary recovery section (103), and a mixing section (107) disposed on the hot air section (106). The heating mechanism (200) includes a hydrolysis section (201) disposed between the hydrolysis reaction section (101) and the mixing section (107), and a heating section (202) disposed on the hydrolysis reaction section (101). The hydrolysis reaction section (101) includes a hydrolysis reactor (101a), a coil (101b) disposed in the hydrolysis reactor (101a), and a steam trap (101c) disposed on the coil (101b). The primary recovery unit (102) includes a primary recovery pipe (102d) disposed on the steam trap (101c), a primary air heater (102a) disposed on the primary recovery pipe (102d), a cold dilution air duct (102b) disposed on the primary air heater (102a), and a drain pipe (102c) disposed on the primary air heater (102a). One end of the primary recovery pipe (102d) is connected to the water inlet of the primary air heater (102a), and one end of the drain pipe (102c) is connected to the water outlet of the primary air heater (102a). The secondary recovery unit (103) includes a secondary air heater (103b), a waste heat air duct (103c) disposed between the secondary air heater (103b) and the primary air heater (102a), and a secondary recovery pipe (103a) disposed between the steam trap (101c) and the secondary air heater (103b). The secondary recovery pipe (103a) and the steam trap (101c) are connected by a three-way valve. One end of the secondary recovery pipe (103a) is connected to the water outlet of the secondary air heater (103b).

2. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 1, characterized in that: The pressurization unit (104) includes a check valve (104a) installed on the steam trap (101c) and a booster pump (104b) installed on the primary recovery pipe (102d). The output end of the booster pump (104b) is connected to the inlet end of the primary heater (102a) through the primary recovery pipe (102d).

3. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 2, characterized in that: The auxiliary heating unit (105) includes an auxiliary steam pipe (105a) installed on the secondary air heater (103b), an auxiliary steam flow meter (105b) installed on the auxiliary steam pipe (105a), and an auxiliary steam regulating valve (105c) installed on the auxiliary steam pipe (105a).

4. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 3, characterized in that: The hot air section (106) includes a heat dilution air duct (106a) installed on the secondary air heater (103b), a hot air pressure gauge (106b) installed on the heat dilution air duct (106a), a hot air temperature gauge (106c) installed on the heat dilution air duct (106a), and a hot air flow meter (106d) installed on the heat dilution air duct (106a).

5. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 4, characterized in that: The mixing section (107) includes an ammonia-air mixer (107a) disposed on the hot dilution air duct (106a) and a denitrification reaction tube (107b) disposed on the ammonia-air mixer (107a).

6. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 5, characterized in that: The hydrolysis unit (201) includes a hydrolysis pipe (201a) disposed on the hydrolysis reactor (101a) and connected to the ammonia-air mixer (107a), a hydrolysis regulating valve (201b) disposed on the hydrolysis pipe (201a), and a hydrolysis flow meter (201c) disposed on the hydrolysis pipe (201a).

7. The urea hydrolysis heating steam hydrophobic waste heat recovery device according to claim 6, characterized in that: The heating unit (202) includes a desuperheating and pressure reducing steam pipe (202a), a steam pressure gauge (202b) installed on the desuperheating and pressure reducing steam pipe (202a), a steam temperature gauge (202c) installed on the desuperheating and pressure reducing steam pipe (202a), a steam regulating valve (202d) installed on the desuperheating and pressure reducing steam pipe (202a), a steam flow meter (202e) installed on the desuperheating and pressure reducing steam pipe (202a), and a steam ball valve (202f) installed on the desuperheating and pressure reducing steam pipe (202a). There are two steam ball valves (202f). One end of the desuperheating and pressure reducing steam pipe (202a) is connected to the air inlet end of the coil (101b).

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