Evaporation system with dry type vacuum suction device for urea production
By using a dry vacuum pump to replace the steam jet in the urea production device, a series-connected vacuum pump and condenser system is built, the problem of high steam consumption in urea production is solved, and energy saving and cost reduction are achieved.
Patent Information
- Application Number
- CN202311192273.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-15
- Publication Date
- 2025-07-11
AI Technical Summary
The existing urea production equipment consumes a large amount of steam during the evaporation process, resulting in waste of energy and high production costs, and there is no precedent for dry vacuum pump application.
A dry vacuum pump is used to replace the steam jet, and an evaporation system for urea production is formed through a series of dry vacuum pumps and condensers, including a first-stage evaporation separator, a second-stage evaporation separator, a dry vacuum pump and a condenser to realize vacuum suction.
It greatly saves energy consumption and reduces production costs, while having no impact on the original production system. It can switch back to the original system to operate, suitable for enterprises with high gas prices and low electricity prices.
Smart Images
Figure CN120285598A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of urea production, and more specifically, it relates to an evaporation system for urea production with a dry vacuum pumping device. Background Art
[0002] In a urea production plant, as Figure 1 shown, the outlet of the urea synthesis tower is a five-component gas-liquid mixture composed of NH3, CO2, NH4COONH2, CO(NH2)2, and H2O. After most of the unreacted substances are separated and recovered in the unreacted substance decomposition and recovery system, the material is called urine, and its components are approximately: Ur: 68% (wt), H2O: 29% (wt), NH3: 1.5% (wt), CO2: 0.5% (wt), which enters the urine tank. The urine in the urine tank is pressurized by a urine pump and sent into the evaporation system to complete the separation of water in the urine, and the urine is concentrated to 99.7% (wt) and sent to a granulator for granulation.
[0003] In the above urea production, in order to evaporate water and control the generation of side reactions during the evaporation process, it is required that the evaporation temperature be as low as possible and the evaporation time be as short as possible. Therefore, the existing process generally adopts a two-stage vacuum evaporation process or an inert gas stripping process.
[0004] In Figure 1 , the booster, the first-stage ejector, the first ejector of the second stage, and the second ejector of the second stage are all steam jet-type structures. Using the steam jet as the power, the purpose of sucking the inside of the second-stage evaporation separator, the first-stage evaporation condenser, the first condenser of the second stage, and the second condenser of the second stage to be in a vacuum is achieved, and a large amount of steam is consumed during use.
[0005] During the actual production process, it is detected that the inside of the ejector and its connected pipes are all very clean and there is no scaling. Therefore, if a dry vacuum pump can be used to replace the ejector of the original system, a large amount of steam consumed by the jet can be replaced by electric energy, greatly saving energy consumption and reducing production costs at the same time.
[0006] After inquiry, there is no precedent for using a dry vacuum pump to suck vacuum in this type of production device at present.
[0007] In view of the above technical problems, the applicant has invented an evaporation system for urea production with a dry vacuum pumping device. Summary of the Invention
[0008] The purpose of the present invention is to provide an evaporation system for urea production with a dry vacuum pumping device, which solves the technical problems mentioned in the background art.
[0009] The above technical object of the present invention is achieved through the following technical solutions: An evaporation system for urea production with a dry vacuum pumping device, comprising a first-stage evaporation separator and a second-stage evaporation separator connected in series, and a first-stage evaporation condenser and a second-stage condensation mechanism are respectively provided at the gas outlet ends of the first-stage evaporation separator and the second-stage evaporation separator; a first-stage vacuum pump and a second second-stage vacuum pump are respectively provided at the gas outlet ends of the first-stage evaporation condenser and the second-stage condensation mechanism, and both the first-stage vacuum pump and the second second-stage vacuum pump are dry vacuum pumps.
[0010] The present invention is further provided as follows: The second-stage condensation mechanism includes a boost vacuum pump, a second first-stage condenser, a second second-stage condenser, and a second first-stage vacuum pump; the gas outlet end of the second-stage evaporation separator is connected to the intake end of the boost vacuum pump, and the gas outlet end of the boost vacuum pump is connected to the intake end of the second first-stage condenser; the gas outlet end of the second first-stage condenser is connected to the intake end of the second first-stage vacuum pump, the gas outlet end of the second first-stage vacuum pump is connected to the intake end of the second second-stage condenser, and the gas outlet end of the second second-stage condenser is connected to the intake end of the second second-stage vacuum pump.
[0011] The present invention is further provided as follows: The boost vacuum pump and the second first-stage vacuum pump are dry vacuum pumps.
[0012] In summary, the beneficial effects of the present invention are:
[0013] 1. This system uses a dry vacuum pump to replace the steam jet in the prior art, and can use a small amount of electric energy to replace a large amount of steam consumed on site, generating energy-saving benefits;
[0014] 2. This system has no impact on the original production system. This transformation is in a parallel relationship with the original jet device and does not change the original system at all. If any problems occur in the newly added part, it can be switched to the original system operating state by disconnecting the valve. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a schematic structural diagram of the existing urea production evaporation system in the background art of the present invention;
[0016] Figure 2 is a schematic structural diagram of an evaporation system for urea production with a dry vacuum pumping device in an embodiment of the present invention.
[0017] In the figure: 1. First-stage evaporation separator; 2. Second-stage evaporation separator; 3. Boost vacuum pump; 4. Second first-stage condenser; 5. Second first-stage vacuum pump; 6. Second second-stage condenser; 7. Second second-stage vacuum pump; 8. First-stage vacuum pump; 9. First-stage evaporation condenser. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] The following combines the attached Figure 1A further detailed description of the present invention will be given below.
[0019] Embodiment: An evaporation system for urea production with a dry vacuum pumping device, as Figure 1 shown, which includes a first-stage evaporation separator 1 and a second-stage evaporation separator 2 connected in series. The gas outlets of the first-stage evaporation separator 1 and the second-stage evaporation separator 2 are respectively connected to a first-stage evaporation condenser 9 and a second-stage condensation mechanism; a first-stage vacuum pump 8 and a second-stage second vacuum pump 7 are respectively installed at the gas outlets of the first-stage evaporation condenser and the second-stage condensation mechanism, both of which are dry vacuum pumps.
[0020] Preferably in this embodiment, the second-stage condensation mechanism includes a booster vacuum pump 3, a second-stage first condenser 4, a second-stage second condenser 6 and a second-stage first vacuum pump 5; the gas outlet of the second-stage evaporation separator 2 is connected to the intake end of the booster vacuum pump 3, and the gas outlet of the booster vacuum pump 3 is connected to the intake end of the second-stage first condenser 4; the gas outlet of the second-stage first condenser 4 is connected to the intake end of the second-stage first vacuum pump 5, the gas outlet of the second-stage first vacuum pump 5 is connected to the intake end of the second-stage second condenser 6, and the gas outlet of the second-stage second condenser 6 is connected to the intake end of the second-stage second vacuum pump 7.
[0021] Preferably in this embodiment, the first-stage vacuum pump 8, the second-stage second vacuum pump 7, the booster vacuum pump 3 and the second-stage first vacuum pump 5 are dry vacuum pumps.
[0022] In this embodiment, the internal parameters of the first-stage evaporation separator and the second-stage separator of the evaporation system are fixed, so the parameters of the dry vacuum pump are also fixed. When there are on-site operating parameters, configure the vacuum pump while maintaining the original parameters (vacuum degree and temperature) of the first-stage evaporator, the second-stage evaporator, the first-stage evaporation condenser, the second-stage first condenser 4, and the second-stage second condenser 6. When the original parameters are incomplete, configure the vacuum pump according to the parameters in the following table.
[0023]
[0024]
[0025] After the transformation, the calculation method of the transformation benefit is as follows:
[0026] The generated energy-saving benefit = the cost of live steam consumed by the steam jet at each position before the technical transformation - the power consumption cost required by the vacuum pump at each position after the technical transformation.
[0027] The cost of consuming steam = steam flow * steam price
[0028] The power consumption cost = power consumption * electricity price
[0029] Among them, the steam consumption can be directly obtained by reading the calibrated steam flowmeter in the system. For individual systems without a flowmeter or where it is not easy to install a flowmeter, the original system design data can be queried to estimate the steam volume.
[0030] The electricity consumption should be obtained by installing an ammeter and an integrating timer in the power distribution cabinet for reading.
[0031] The steam price and electricity price should be determined according to the actual situation of each unit. The steam price must be obtained by querying the enthalpy-entropy table with the actual pressure to get the enthalpy value, and then the actual price is converted according to the enthalpy value.
[0032] In this embodiment, the following effects have been achieved by this transformation method:
[0033] 1. A small amount of electric energy is used to replace the steam consumed by the original system's jet. Taking this project as an example, before the technical transformation of this project, 12 t / h of 0.4 MPa live steam was consumed. After the transformation to a vacuum pump, no steam is consumed. The total power consumption of each vacuum pump is 600 kW / h. The steam price of this factory is 180 yuan / t, and the electricity price is 0.4 yuan / kW·h. Before the technical transformation, the energy consumption cost was 2160 yuan / h, and after the technical transformation, the energy consumption cost was 240 yuan / h, saving 89% of the energy consumption cost. This transformation method is applicable to enterprises with a relatively high steam price, a low electricity price, or less steam production and more electricity production. The energy-saving benefit also varies with the steam-electricity settlement price of each enterprise.
[0034] 2. It has no impact on the original production system. This transformation belongs to an additional parallel transformation and does not change the original system at all. If any problems occur in the new part, the original system operation state can be switched through the valve.
[0035] This specific embodiment is only an explanation of the present invention and is not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.
Claims
1. An evaporation system for urea production with a dry vacuum pumping device, characterized in that: It includes a first-stage evaporation separator (1) and a second-stage evaporation separator (2) connected in series. A first-stage evaporation condenser (9) and a second-stage condensation mechanism are respectively provided at the gas outlets of the first-stage evaporation separator (1) and the second-stage evaporation separator (2); a first-stage vacuum pump (8) and a second second-stage vacuum pump (7) are respectively provided at the gas outlets of the first-stage evaporation condenser and the second-stage condensation mechanism. Both the first-stage vacuum pump (8) and the second second-stage vacuum pump (7) are dry vacuum pumps.
2. The evaporation system for urea production with a dry vacuum pumping device according to claim 1, characterized in that: The second-stage condensation mechanism includes a booster vacuum pump (3), a first second-stage condenser (4), a second second-stage condenser (6) and a first second-stage vacuum pump (5); the gas outlet of the second-stage evaporation separator (2) is connected to the inlet of the booster vacuum pump (3), and the gas outlet of the booster vacuum pump (3) is connected to the inlet of the first second-stage condenser (4); the gas outlet of the first second-stage condenser (4) is connected to the inlet of the first second-stage vacuum pump (5), the gas outlet of the first second-stage vacuum pump (5) is connected to the inlet of the second second-stage condenser (6), and the gas outlet of the second second-stage condenser (6) is connected to the inlet of the second second-stage vacuum pump (7).
3. The evaporation system for urea production with a dry vacuum suction device according to claim 2, characterized in that: Both the booster vacuum pump (3) and the first second-stage vacuum pump (5) are dry vacuum pumps.