System for co-producing urea by using propane dehydrogenation propylene preparation device
By combining the hydrogen-rich gas of the propane dehydrogenation device with nitrogen in the air, and using the carbon dioxide exhaust gas of the propane dehydrogenation device for urea production, the problems of waste of hydrogen resources and carbon dioxide emissions are solved, and the deep utilization of hydrogen and carbon dioxide is achieved, improving the improvement of Product added value and corporate profits.
Patent Information
- Application Number
- CN202323321372.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2033-12-06
AI Technical Summary
The high-concentration hydrogen resources produced by the existing propane dehydrogenation and propylene device are difficult to effectively utilize, and due to the safety risks, the process is complicated and resources are wasted.
Design a system for co-production of urea using propane dehydrogenation device, and use the hydrogen-rich gas produced in the propane dehydrogenation device to be used as raw material for synthesis of ammonia through the propane dehydrogenation device separation system and nitrogen gas in the air separation device as the raw material for synthesis of ammonia, and use the propane dehydrogenation device reaction system in the propane dehydrogenation device The carbon dioxide exhaust gas is purified and used for urea production.
It has achieved in-depth utilization of hydrogen resources, avoided the risk of hydrogen explosion, increased product added value, effectively solved the problem of carbon dioxide emissions, and increased corporate profits.
Smart Images
Figure CN222111765U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of urea production, in particular to a system for co-producing urea by utilizing a propane dehydrogenation propylene production device. Background Art
[0002] Propane dehydrogenation to propylene (PDH unit) is one of the main propylene production technologies at present. Currently, the world's mature technology providers are UOP and Lummus, and the process names are Oleflex and Catofin respectively. There are many industrial units around the world. Many PDH units in China are supported by the technology of these two companies. In addition to the main product propylene, these two different production processes will produce a large amount of hydrogen resources as a by-product, and the amount of by-product hydrogen is relatively large. As we all know, due to the high storage and transportation costs of hydrogen (i.e., the long-distance transportation cost is low), domestic companies using PDH units generally use hydrogen as fuel gas and transport it to the boiler through pipelines for combustion to achieve the purpose of by-product steam. The hydrogen produced in the PDH unit has a high concentration, so it needs to be pretreated before being sent to the boiler (to prevent the risk of explosion). Not only is the process cumbersome, but it also causes a waste of hydrogen resources. Utility Model Content
[0003] The purpose of the utility model is to provide a backwashing filtration system to solve the problems raised in the above background technology.
[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0005] A system for co-producing urea by using a propane dehydrogenation to produce propylene device comprises a propane dehydrogenation device, wherein a byproduct hydrogen-rich gas pipeline in a propane dehydrogenation device separation system in the propane dehydrogenation device is connected to a PSA hydrogen extraction device, a hydrogen outlet of the PSA hydrogen extraction device is connected to an ammonia synthesis device, a nitrogen inlet of the ammonia synthesis device is connected to a nitrogen outlet in an air separation device, a product outlet of the ammonia synthesis device is connected to an ammonia synthesis inlet of a urea synthesis device; a carbon dioxide unit is connected to a carbon dioxide inlet of a urea synthesis device, and the urea synthesis device is connected to a urea storage tank.
[0006] The beneficial effects of the utility model are as follows: the utility model utilizes the hydrogen-rich gas produced in the separation system of the propane dehydrogenation device as a basis, purifies the hydrogen-rich gas and uses it together with the nitrogen from the air separation device as a raw material for producing synthetic ammonia, so as to achieve deep utilization of hydrogen resources and avoid the defect that hydrogen needs to be pretreated before combustion in the boiler to prevent explosion; further, the synthetic ammonia produced in the utility model is combined with carbon dioxide to produce urea, so as to achieve the characteristic of increasing the added value of the product.
[0007] Preferably, the nitrogen outlet of the air separation unit is connected to the nitrogen inlet of the synthetic ammonia unit through a first valve, and the hydrogen outlet of the PSA hydrogen extraction unit is connected to the synthetic ammonia unit through a second valve.
[0008] Preferably, a first flow meter is provided between the nitrogen outlet of the air separation device and the first valve, and a second flow meter is provided between the hydrogen outlet of the PSA hydrogen extraction device and the second valve.
[0009] Preferably, the carbon dioxide unit is a carbon dioxide storage tank and / or a self-produced carbon dioxide part of a propane dehydrogenation device.
[0010] Preferably, the self-produced carbon dioxide unit includes a propane dehydrogenation unit reaction system in the propane dehydrogenation unit, the exhaust gas outlet of the heating furnace in the propane dehydrogenation unit reaction system is connected to the carbon dioxide purification device through a pretreatment unit, and the outlet of the carbon dioxide purification device is connected to the carbon dioxide inlet of the urea synthesis device.
[0011] Preferably, the pretreatment unit comprises a cooling heat exchanger connected to the exhaust gas outlet of the heating furnace, and a dryer connected to the outlet of the cooling heat exchanger.
[0012] Preferably, a third valve is provided between the product outlet of the synthetic ammonia device and the synthetic ammonia inlet of the urea synthesis device, and a fourth valve is provided between the carbon dioxide unit and the carbon dioxide inlet of the urea synthesis device.
[0013] Preferably, a third flow meter is provided between the product outlet of the synthetic ammonia device and the third valve, and a fourth flow meter is provided between the carbon dioxide unit and the fourth valve.
[0014] A system for co-producing urea by using a propane dehydrogenation to produce propylene device is manufactured according to the above scheme. The utility model uses the hydrogen-rich gas produced in the separation system of the propane dehydrogenation device as a basis to purify the hydrogen-rich gas and use it together with the nitrogen from the air separation device as a raw material for producing synthetic ammonia, so as to achieve deep utilization of hydrogen resources; further, utilizing the characteristic that the tail gas in the heating furnace in the reaction system of the propane dehydrogenation device contains a large amount of carbon dioxide, the tail gas is treated and purified, and it is combined with synthetic ammonia for producing urea. The above method can not only solve the technical problems of hydrogen explosion risk and large-scale carbon dioxide emissions, but also achieve deep utilization of hydrogen resources and carbon dioxide resources, so as to achieve the characteristics of turning waste into treasure and increasing corporate profits. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of the structure of the utility model.
[0016] Figure 2 This is another structural schematic diagram of the utility model.
[0017] In the figure: 1. propane dehydrogenation unit; 2. propane dehydrogenation unit separation system; 3. PSA hydrogen extraction unit; 4. ammonia synthesis unit; 5. air separation unit; 6. urea synthesis unit; 7. urea storage tank; 8. carbon dioxide storage tank; 9. propane dehydrogenation unit reaction system; 10. heating furnace; 11. carbon dioxide purification unit; 12. cooling heat exchanger; 13. dryer; 14. first valve; 15. second valve; 16. third valve; 17. fourth valve; 18. first flow meter; 19. second flow meter; 20. third flow meter; 21. fourth flow meter. DETAILED DESCRIPTION
[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0019] See also Figure 1-2The utility model is a system for co-producing urea by using a propane dehydrogenation to produce propylene device, comprising a propane dehydrogenation device 1, a by-product hydrogen-rich gas pipeline in a propane dehydrogenation device separation system 2 in the propane dehydrogenation device 1 is connected to a PSA hydrogen extraction device 3, a hydrogen outlet of the PSA hydrogen extraction device 3 is connected to an ammonia synthesis device 4, a nitrogen inlet of the ammonia synthesis device 4 is connected to a nitrogen outlet in an air separation device 5, a product outlet of the ammonia synthesis device 4 is connected to an ammonia synthesis inlet of a urea synthesis device 6; a carbon dioxide unit is connected to a carbon dioxide inlet of the urea synthesis device 6, and the urea synthesis device 6 is connected to a urea storage tank 7. The hydrogen-rich gas produced by the separation system 2 of the propane dehydrogenation device described in the utility model enters the PSA hydrogen extraction device 3 through the by-product hydrogen-rich gas pipeline for pressure swing adsorption to achieve the purpose of recovering hydrogen and improving purity. The hydrogen after pressure swing adsorption is used as a raw material to enter the synthetic ammonia device 4, and the nitrogen obtained by air separation in the air separation device 5 enters the synthetic ammonia device 4 at the same time. The above two raw materials produce synthetic ammonia in the synthetic ammonia device 4, and further use the synthetic ammonia as a raw material to enter the urea synthesis device 6 together with the carbon dioxide from the carbon dioxide unit for urea synthesis; the above method can prevent the risk of hydrogen explosion, and can realize the deep utilization of hydrogen resources to improve its added value and enhance the competitiveness of the enterprise; it should be noted that the carbon dioxide in the carbon dioxide unit described in the utility model can be purchased from outside, or carbon dioxide produced in other sections; the propane dehydrogenation device 1 described in the utility model includes a dehydrogenation reactor, a chloride processor, a deethanizer, a depropanizer, a product separation tower, etc. , but not limited to the above equipment, which is the prior art so it will not be repeated; the propane dehydrogenation device separation system 2 includes a cold combined feed heat exchanger, a high-pressure separator, a high-pressure turbine expander, a medium-pressure separator, a low-pressure turbine expander, a low-pressure separator, a dry gas cooler, etc., but not limited to the above equipment, which is the prior art so it will not be repeated; the PSA hydrogen extraction device 3 includes several adsorption towers, a raw gas compressor, etc., but not limited to the above equipment, which is the prior art so it will not be repeated; the synthetic ammonia device 4 includes an ammonia synthesis tower, an ammonia synthesis water cooler, an ammonia washing tower, a waste heat boiler, etc., but not limited to the above equipment, which is the prior art so it will not be repeated; the air separation device 5 includes an air compressor, an air cooling tower, an evaporative cooling tower, a molecular sieve adsorption tower, etc., but not limited to the above equipment, which is the prior art so it will not be repeated; the urea synthesis device 6 includes a urea synthesis tower, a CO2 compressor, an ammonia preheater, a decomposition tower, an absorption tower, etc., but not limited to the above equipment, which is the prior art so it will not be repeated.
[0020] Furthermore, the nitrogen outlet of the air separation device 5 is connected to the nitrogen inlet of the synthetic ammonia device 4 through the first valve 14, and the hydrogen outlet of the PSA hydrogen extraction device 3 is connected to the synthetic ammonia device 4 through the second valve 15. The first valve 14 and the second valve 15 can be used to adjust the flow ratio between hydrogen and nitrogen to achieve smooth operation of the synthetic ammonia device 4 system.
[0021] Furthermore, a first flowmeter 18 is provided between the nitrogen outlet of the air separation device 5 and the first valve 14, and a second flowmeter 19 is provided between the hydrogen outlet of the PSA hydrogen extraction device 3 and the second valve 15. The first flowmeter 18 can be used to monitor the flow rate of nitrogen, and the second flowmeter 19 is used to monitor the flow rate of hydrogen. The first flowmeter 18 and the second flowmeter 19 can provide a basis for adjusting the opening of the first valve 14 and the second valve 15.
[0022] Further, see Figure 1-2 The carbon dioxide unit is the carbon dioxide storage tank 8 and / or the self-produced carbon dioxide part of the propane dehydrogenation device. The carbon dioxide in the carbon dioxide storage tank 8 described in the utility model can be purchased from outside or produced in other sections; it can also be carbon dioxide from the propane dehydrogenation device.
[0023] Further, see Figure 2 The self-produced carbon dioxide unit includes a propane dehydrogenation device reaction system 9 in a propane dehydrogenation device 1. The tail gas outlet of the heating furnace 10 in the propane dehydrogenation device reaction system 9 is connected to a carbon dioxide purification device 11 through a pretreatment unit, and the outlet of the carbon dioxide purification device 11 is connected to the carbon dioxide inlet of the urea synthesis device 6. The carbon dioxide in the propane dehydrogenation device described in the utility model comes from the tail gas of the heating furnace 10. By utilizing the tail gas of the heating furnace 10, the emission of carbon dioxide can be reduced to meet the environmental protection requirements. The carbon dioxide purification device 11 is used to increase the concentration of carbon dioxide to not less than 98% to meet the requirements of urea production; the propane dehydrogenation device reaction system 9 includes a heat combined feed heat exchanger, a heating furnace, a dehydrogenation reactor, etc., but is not limited to the above equipment, which is a prior art and therefore will not be repeated; the carbon dioxide purification device 11 includes a desulfurization tower, a light removal tower, an ice machine, etc., but is not limited to the above equipment, which is a prior art and therefore will not be repeated.
[0024] Furthermore, the pretreatment unit includes a cooling heat exchanger 12 connected to the exhaust gas outlet of the heating furnace 10, and a dryer 13 connected to the outlet of the cooling heat exchanger 12. The above arrangement can cool the exhaust gas and remove moisture from the exhaust gas after cooling, laying the foundation for the subsequent purification using the carbon dioxide purification device 11. The pretreatment unit described in the utility model is mainly used to cool the exhaust gas and remove moisture.
[0025] Furthermore, a third valve 16 is provided between the product outlet of the synthetic ammonia device 4 and the synthetic ammonia inlet of the urea synthesis device 6, and a fourth valve 17 is provided between the carbon dioxide unit and the carbon dioxide inlet of the urea synthesis device 6. The third valve 16 and the fourth valve 17 can be used to adjust the flow ratio between the synthetic ammonia and the carbon dioxide to achieve the smooth operation of the urea synthesis device 6 system.
[0026] Furthermore, a third flowmeter 20 is provided between the product outlet of the synthetic ammonia device 4 and the third valve 16, and a fourth flowmeter 21 is provided between the carbon dioxide unit and the fourth valve 17. The third flowmeter 20 and the fourth flowmeter 21 are provided to monitor the flow rates of synthetic ammonia and carbon dioxide, respectively, and can provide a basis for adjusting the opening of the third valve 16 and the fourth valve 17.
[0027] The working principle of the utility model is as follows: the propane dehydrogenation device 1 is in operation for producing propylene, the propane dehydrogenation device separation system 2 and the propane dehydrogenation device reaction system 9 are in operation at the same time, the hydrogen-rich gas produced by the propane dehydrogenation device separation system 2 enters the PSA hydrogen extraction device 3 through the byproduct hydrogen-rich gas pipeline for pressure swing adsorption to achieve the purpose of recovering hydrogen and improving the purity (the purity of the hydrogen after passing through the PSA hydrogen extraction device 3 is above 99.9%), the hydrogen after pressure swing adsorption is used as a raw material to enter the synthetic ammonia device 4, and the nitrogen obtained by air separation in the air separation device 5 (the nitrogen purity is above 99.9%) is ) enter the synthetic ammonia device 4 at the same time, the above two raw materials produce synthetic ammonia in the synthetic ammonia device 4, the heating furnace 10 in the propane dehydrogenation device reaction system 9 produces tail gas, the tail gas enters the cooling heat exchanger 12 through the tail gas outlet for heat exchange, the tail gas temperature after heat exchange is 40-60°C, the tail gas after heat exchange enters the dryer 13 to remove moisture (the moisture content in the tail gas after passing through the dryer 13 is reduced to less than 0.1%), and finally enters the carbon dioxide purification device 11 for purification (the purity of the purified carbon dioxide is more than 99.9%), the purified carbon dioxide and the above synthetic ammonia are used as raw materials to enter the urea synthesis device 6 for production The urea product enters the urea storage tank 7 for temporary storage and then is sold. In the utility model, the flow meter and the corresponding valve are used to cooperate to achieve the stable operation of the whole system. Specifically, the first flow meter 18 is set to monitor the flow of nitrogen, and the second flow meter 19 is used to monitor the flow of hydrogen. The opening of the first valve 14 and the second valve 15 is controlled by setting the flow data in the first flow meter 18 and the second flow meter 19, so as to adjust the ratio between hydrogen and nitrogen. The third flow meter 20 is set to monitor the flow of synthetic ammonia, and the fourth flow meter 21 is set to monitor the flow of carbon dioxide. The flow data in the fourth flow meter 21 is used to control the opening of the third valve 16 and the fourth valve 17, thereby controlling the ratio between synthetic ammonia and carbon dioxide. The utility model uses the by-product hydrogen as the raw material of synthetic ammonia and further uses the synthetic ammonia for the production of urea, which can solve the defect of hydrogen being explosive and realize the deep utilization of hydrogen resources. At the same time, the utility model can also effectively solve the problem that the exhaust gas discharged by the heating furnace 10 in the reaction system 9 of the alkane dehydrogenation device contains a large amount of carbon dioxide. It has the characteristics of reasonable design, safety and environmental protection, and realizes the deep utilization of hydrogen and carbon dioxide, so as to achieve the goal of turning waste into treasure and increasing corporate profits.
[0028] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A system for co-producing urea by using a propane dehydrogenation to propylene device, comprising a propane dehydrogenation device (1), characterized in that: The by-product hydrogen-rich gas pipeline in the propane dehydrogenation device separation system (2) in the propane dehydrogenation device (1) is connected to the PSA hydrogen extraction device (3), the hydrogen outlet of the PSA hydrogen extraction device (3) is connected to the synthetic ammonia device (4), the nitrogen inlet of the synthetic ammonia device (4) is connected to the nitrogen outlet of the air separation device (5), and the product outlet of the synthetic ammonia device (4) is connected to the synthetic ammonia inlet of the urea synthesis device (6); the carbon dioxide unit is connected to the carbon dioxide inlet of the urea synthesis device (6), and the urea synthesis device (6) is connected to the urea storage tank (7).
2. The system for co-producing urea by using a propane dehydrogenation to propylene unit according to claim 1, characterized in that: The nitrogen outlet of the air separation unit (5) is connected to the nitrogen inlet of the ammonia synthesis unit (4) through a first valve (14), and the hydrogen outlet of the PSA hydrogen extraction unit (3) is connected to the ammonia synthesis unit (4) through a second valve (15).
3. The system for co-producing urea by using a propane dehydrogenation to propylene unit according to claim 2, characterized in that: A first flow meter (18) is provided between the nitrogen outlet of the air separation device (5) and the first valve (14), and a second flow meter (19) is provided between the hydrogen outlet of the PSA hydrogen extraction device (3) and the second valve (15).
4. A system for co-producing urea by using a propane dehydrogenation to propylene unit according to any one of claims 1 to 3, characterized in that: The carbon dioxide unit is a carbon dioxide storage tank (8) and / or a self-produced carbon dioxide part of a propane dehydrogenation device.
5. The system for co-producing urea by using a propane dehydrogenation to propylene device according to claim 4, characterized in that: The self-produced carbon dioxide unit comprises a propane dehydrogenation device reaction system (9) in a propane dehydrogenation device (1), wherein the tail gas outlet of a heating furnace (10) in the propane dehydrogenation device reaction system (9) is connected to a carbon dioxide purification device (11) through a pretreatment unit, and the outlet of the carbon dioxide purification device (11) is connected to a carbon dioxide inlet of a urea synthesis device (6).
6. The system for co-producing urea by using a propane dehydrogenation to propylene unit according to claim 5, characterized in that: The pretreatment unit comprises a cooling heat exchanger (12) connected to the tail gas outlet of the heating furnace (10), and a dryer (13) connected to the outlet of the cooling heat exchanger (12).
7. The system for co-producing urea by using a propane dehydrogenation to propylene unit according to claim 1, characterized in that: A third valve (16) is provided between the product outlet of the synthetic ammonia device (4) and the synthetic ammonia inlet of the urea synthesis device (6), and a fourth valve (17) is provided between the carbon dioxide unit and the carbon dioxide inlet of the urea synthesis device (6).
8. The system for co-producing urea by using a propane dehydrogenation to propylene unit according to claim 7, characterized in that: A third flow meter (20) is provided between the product outlet of the synthetic ammonia device (4) and the third valve (16), and a fourth flow meter (21) is provided between the carbon dioxide unit and the fourth valve (17).