Cooling apparatus and method for ammonia-based decarbonation

Abstract

A cooling apparatus and method for ammonia-based decarbonation. The cooling apparatus uses a first circulating liquid to cool the process gas to T gas a first stage cooling zone that may cool the process gas to a temperature of T gas a second stage cooling zone, which may cool the process gas to a temperature of T gas a third stage cooling functional zone for cooling the first circulating liquid to a temperature of T3; a first cold source for cooling the first circulating liquid; a second cold source for cooling the second circulating liquid; and a third cold source for cooling the third circulating liquid; gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas when it enters the first stage cooling function zone, and the three cold sources can be different. The device and method of the present invention respectively use circulating water or closed cooling tower or air cooler, low temperature process gas, cooling liquid or cooling equipment for staged cooling to make full use of low-energy cold and reuse of cold of process gas, save investment costs and reduce energy consumption.

Description

[Technical field]

[0001] The present invention belongs to the technical field of environmental protection, and in particular to a pre-cooling device and method for stepwise cooling of process gas before ammonia-based decarbonation. [Background technology]

[0002] In recent years, the greenhouse effect has gradually become one of the most serious problems facing mankind. 2 ) is the most important greenhouse gas, and the use of fossil energy is its main source. China's total CO 2 China's carbon emissions rank first in the world, and the situation in which China's energy structure is dominated by coal will continue for some time, so coal energy will still be the basis of the new energy peak regulations and energy security. China has committed to reaching the peak of carbon emissions by 2030 and reaching carbon neutrality by 2060. CO in exhaust gas 2 Capture, storage and resource recovery of greenhouse gases are crucial to controlling and reducing greenhouse gas emissions and combating the greenhouse effect and global warming.

[0003] At present, the organic amine-based method is the most widely used carbon capture technology in the world. However, it has problems such as high running costs, large amounts of three waste materials discharged outside the system, and difficult processing. New decarbonation technologies have also been actively researched at home and abroad. Compared with the organic amine-based method, the ammonia-based method has the advantages of easy regeneration, low running costs, and the by-product of decarbonation is ammonium bicarbonate, an important fertilizer.

[0004] Ammonium bicarbonate is a nitrogen fertilizer and CO 2 It is a typical compound fertilizer that can simultaneously supply plants with CO. It is particularly suitable for modern agriculture with soilless cultivation and greenhouse plant growth. 2To truly realize resource utilization of the current level, achieve carbon circulation, and reduce secondary pollution and CO emissions that may be caused by underground carbon storage. 2 It also avoids environmental accidents. Compared to decarboxylation with organic amines, ammonia is 2 and the product ammonium bicarbonate is more easily regenerated, significantly reducing the cost of decarbonation.

[0005] Ammonia-based decarbonation technology is a research focus and a method to manage greenhouse gases. However, ammonia is volatile and ammonia leakage increases. If left unchecked, large amounts of ammonia leakage not only increase the cost of decarbonation but also cause secondary pollution. To address this issue, lowering the temperature of decarbonation can be used to reduce ammonia leakage.

[0006] China Patent Application No. 201210410873.0 discloses a multi-stage cooling tower system with multiple cooling towers, in which the outlet water of the preceding cooling tower is used as the inlet water of the succeeding cooling tower to perform multi-stage cooling. This device only performs multi-tower cooling with the same cooling gradient to improve cooling efficiency, and uses the same cold source.

[0007] Chinese Patent Application No. 200880122376.2 discloses a multi-stage CO2 ion exchange method for treating a flue gas stream. 2 A removal system and method is disclosed in which an absorption vessel is used to contact a flue gas stream with an ionic solution containing ammonia at a low temperature between 0-20° C., while the solution in the first absorption stage has a higher temperature and a lower ammonia to carbon ratio than the solution in the third absorption stage. By controlling the ionic solution at a low temperature and the ionic solution in the third stage at an even lower temperature, ammonia leakage can be reduced, but the patent is silent as to how to reduce the temperature in an efficient and energy-saving manner.

[0008] It is desirable to provide a multi-stage cooling apparatus and method for wet ammonia-based decarbonation, which can stepwise cool the desulfurized gas in the cooling tower through different cold sources, thus saving investment costs and reducing energy consumption. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] China Patent Application No. 201210410873.0 [Patent Document 2] Chinese Patent Application No. 200880122376.2 Summary of the Invention

[0010] The present invention achieves the above objectives through the following technical solutions: In a first aspect, the present invention provides a pre-cooling apparatus for ammonia-based decarbonation, the pre-cooling apparatus comprising: a first circulating liquid for cooling a process gas to T gas 1 A first stage cooling zone that cools the process gas to a temperature of T gas 2 A second cooling zone is used to cool the process gas to a temperature of T gas 3 a third cooling function zone for cooling the first circulating liquid to a temperature of T; a first cold source for cooling the first circulating liquid; a second cold source for cooling the second circulating liquid; and a third cold source for cooling the third circulating liquid; gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas when it enters the first stage cooling function zone, and the three cold sources are different, providing a pre-cooling device.

[0011] In a second aspect, the present invention provides a method for cooling a process gas, the method comprising: cooling the process gas to a temperature of T using a first circulating liquid. gas 1 A first stage cooling zone that cools the process gas to a temperature of Tgas 2 A second cooling zone is used to cool the process gas to a temperature of T gas 3 a third stage cooling functional zone for cooling the process gas to a temperature of T; cooling the first circulating liquid using a first cold source; cooling the second circulating liquid using a second cold source; and cooling the third circulating liquid using a third cold source; gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas as it enters the first stage cooling function zone, and the three cold sources provide different methods.

[0012] Preferably, the first cold source is circulating cooling water or cooling water from a closed cooling tower, and the first circulating liquid is cooled by a first heat exchanger, or the first cold source is air, and the first circulating liquid is cooled directly by an air cooler. Preferably, the second cold source is decarbonated low-temperature process gas, and the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger, or the second circulating liquid is cooled by direct heat exchange via cross-spraying of the spray liquid. Preferably, the third cold source is a cooling liquid, and preferably, the cooling liquid is obtained by a cooling device, and the third circulating liquid is cooled by a third heat exchanger, or the third circulating liquid is cooled directly by the cold source of the cooling device.

[0013] The apparatus and method of the present invention respectively use circulating cooling water or closed cooling tower or air cooler, low temperature process gas, cooling liquid as cold source, and cool the process gas by spraying the circulating liquid, making full use of low energy cold and reuse of cold of the process gas, saving investment cost and reducing energy consumption. In addition, the apparatus and method of the present invention allows the temperature of the process gas to be reduced to a lower level, for example, 10-30°C, which can significantly reduce ammonia leakage in the subsequent decarbonation process. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 shows a pre-cooling device before ammonia-based decarbonation according to the first embodiment. [Diagram 2] FIG. 2 shows a pre-cooling device before ammonia-based decarbonation according to the second embodiment. [Diagram 3] FIG. 3 shows a pre-cooling device before ammonia-based decarbonation according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In a first aspect, the present invention provides a pre-cooling apparatus for ammonia-based decarbonation, the pre-cooling apparatus comprising: a first circulating liquid for cooling a process gas to T gas 1 A first stage cooling zone that cools the process gas to a temperature of T gas 2 A second cooling zone is used to cool the process gas to a temperature of T gas 3 a third cooling function zone for cooling the first circulating liquid to a temperature of T; a first cold source for cooling the first circulating liquid; a second cold source for cooling the second circulating liquid; and a third cold source for cooling the third circulating liquid; gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas when it enters the first stage cooling function zone, and the three cold sources are different, providing a pre-cooling device.

[0016] In one embodiment, the first cold source is circulating cooling water or cold water from a closed cooling tower, and the first circulating liquid is cooled by a first heat exchanger.

[0017] In one embodiment, the first cold source is air and the first circulating liquid is cooled directly by an air cooler.

[0018] In one embodiment, the second cold source is a decarbonated cold process gas and the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger or the second circulating liquid is cooled by direct heat exchange via cross-spray of atomized liquid.

[0019] In one embodiment, the third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device and the third circulating liquid is cooled by a third heat exchanger or the third circulating liquid is directly cooled by the cold source of the cooling device.

[0020] The first and third heat exchangers are liquid-liquid heat exchangers, preferably plate heat exchangers, and the second heat exchanger is a gas-liquid heat exchanger, preferably a shell-and-tube heat exchanger.

[0021] In one embodiment, a gas-only passing device or component is provided between the cooling functional zones.

[0022] In one embodiment, at least one layer of liquid distributor is provided for each cooling functional zone.

[0023] The liquid distributor may be a trough distributor or a spray distributor.

[0024] In one embodiment, the three functional zones may be combined into one tower or may exist as multiple towers.

[0025] When the three functional zones are combined into one tower, i.e., a cooling tower, the cooling device of the present invention includes a cooling tower and a cold source. The cooling tower includes, from bottom to top, a first stage cooling functional zone, a second stage cooling functional zone, and a third stage cooling functional zone, each of which may be arranged as described herein.

[0026] In one embodiment, T gas 0 is in the range of 40 to 80°C, and / or T gas 1is in the range of 35 to 48°C, and / or T gas 2 is in the range of 15 to 40°C, and / or T gas 3 The range is 10 to 30 degrees Celsius.

[0027] In one embodiment, the temperature of the first circulating liquid when it enters the column is T liquid 1 and the temperature of the first circulating liquid when it leaves the column is T liquid 1’ and T liquid 1 <T liquid 1’ and T gas 0 -T liquid 1’ = ΔT 1 and the temperature of the second circulating liquid when it enters the tower is T liquid 2 and the temperature of the second circulating liquid when it leaves the column is T liquid 2’ and T liquid 2 < Tliquid 2’ and T gas 1 -T liquid 2’ = ΔT 2 and the temperature of the third circulating liquid when it enters the tower is T liquid 3 and the temperature of the third circulating liquid when it leaves the column is T liquid 3’ and T liquid 3 <T liquid 3’ and T gas 2 -T liquid 3’ = ΔT 3 and ΔT 1 , ΔT 2 and ΔT 3 are each independently 1°C or higher, preferably 2 to 15°C, and more preferably 2 to 5°C.

[0028] In one embodiment, T liquid 1 is in the range of 10 to 40°C, and T liquid 1’ is in the range of 15 to 50°C, and / or T liquid 2 is in the range of 15 to 36°C, and T liquid 2’ is in the range of 20 to 45°C, and / or T liquid 3 is in the range of 0 to 25°C, and T liquid 3’ The range is 10 to 40 degrees Celsius.

[0029] In one embodiment, the temperature of the first cold source is Tsource 1 After heat exchange, Tsource 1’ and T source 1 <T source 1’ and the temperature of the second cold source is T source 2 After the heat exchange, T source 2’ and T source 2 <T source 2’ The temperature of the third cold source is T source 3 After the heat exchange, T source 3’ and T source 3 <T source 3’ It is.

[0030] In one embodiment, T source 1 is in the range of 5 to 35°C, and T source 1’ is in the range of 10 to 45°C, and / or T source 2 is in the range of 10 to 30°C, and T source 2’ is in the range of 15 to 40°C, and / or T source 3 is in the range of -17 to 10°C, and T source 3’ The range is 0 to 30 degrees Celsius.

[0031] In one embodiment, the cooling device is part of an ammonia-based desulfurization and decarbonation system, the upstream of the cooling device is connected to the desulfurization device, the downstream of the cooling device is connected to the decarbonation device, and the process gas comes from the desulfurization device and enters the decarbonation device after being cooled by the cooling device.

[0032] Preferably, the process gas is a desulfurized process gas from a desulfurization unit. The process gas has a temperature of 40 to 80° C., preferably 40 to 60° C. The desulfurization process comprises removing SO 2 from the process gas. 2 As a result, the desulfurized process gas contains mainly CO 2 and a small amount of H 2 Contains O.

[0033] In a second aspect, the present invention provides a method for cooling a process gas, the method comprising: cooling the process gas to a temperature of T using a first circulating liquid. gas 1A first stage cooling zone that cools the process gas to a temperature of T gas 2 A second cooling zone is used to cool the process gas to a temperature of T gas 3 a third stage cooling functional zone for cooling the process gas to a temperature of T; cooling the first circulating liquid using a first cold source; cooling the second circulating liquid using a second cold source; and cooling the third circulating liquid using a third cold source; gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas as it enters the first stage cooling function zone, and the three cold sources provide different methods.

[0034] In one embodiment, the first cold source is circulating cooling water or cooling water from a closed cooling tower, and the first circulating liquid is cooled by a first heat exchanger.

[0035] In one embodiment, the first cold source is air and the first circulating liquid is cooled directly by an air cooler.

[0036] In one embodiment, the second cold source is a decarbonated cold process gas and the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger or the second circulating liquid is cooled by direct heat exchange via cross-spray of atomized liquid.

[0037] In one embodiment, the third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device, and the third circulating liquid is cooled by a third heat exchanger, or the third circulating liquid is directly cooled by the cold source of the cooling device.

[0038] In one embodiment, T gas 0 is in the range of 40 to 80°C, and / or T gas 1 is in the range of 35 to 48°C, and / or T gas 2is in the range of 15 to 40°C, and / or T gas 3 The range is 10 to 30 degrees Celsius.

[0039] In one embodiment, the temperature of the first circulating liquid when it enters the column is T liquid 1 and the temperature of the first circulating liquid when it leaves the column is T liquid 1’ and T liquid 1 <T liquid 1’ and T gas 0 -T liquid 1’ = ΔT 1 and the temperature of the second circulating liquid when it enters the tower is T liquid 2 and the temperature of the second circulating liquid when it leaves the column is T liquid 2’ and T liquid 2 <T liquid 2’ and T gas 1 -T liquid 2’ = ΔT 2 and the temperature of the third circulating liquid when it enters the tower is T liquid 3 and the temperature of the third circulating liquid when it leaves the column is T liquid 3’ and T liquid 3 <T liquid 3’ and T gas 2 -T liquid 3’ = ΔT 3 and ΔT 1 , ΔT 2 and ΔT 3 are each independently 1°C or higher, preferably 2 to 15°C, and more preferably 2 to 5°C.

[0040] In one embodiment, T liquid 1 is in the range of 10 to 40°C, and T liquid 1’ is in the range of 15 to 50°C, and / or T liquid 2 is in the range of 15 to 36°C, and T liquid 2’ is in the range of 20 to 45°C, and / or T liquid 3 is in the range of 0 to 25°C, and T liquid 3’ The range is 10 to 40 degrees Celsius.

[0041] In one embodiment, the temperature of the first cold source is T source 1 After the heat exchange, T source 1’ and Tsource 1 <T source 1’ and the temperature of the second cold source is T source 2 After the heat exchange, T source 2’ and T source 2 <T source 2’ The temperature of the third cold source is T source 3 After the heat exchange, T source 3’ and T source 3 <T source 3’ It is.

[0042] In one embodiment, T source 1 is in the range of 5 to 35°C, and T source 1’ is in the range of 10 to 45°C, and / or T source 2 is in the range of 10 to 30°C, and T source 2’ is in the range of 15 to 40°C, and / or T source 3 is in the range of -17 to 10°C, and T source 3’ The range is 0 to 30 degrees Celsius.

[0043] In one embodiment, the method is part of an ammonia-based desulfurization and decarbonation method. Upstream of the cooling method is a desulfurization process. Downstream of the cooling method is a decarbonation process. Process gas comes from the desulfurization process and enters the decarbonation process after being cooled by the cooling method.

[0044] In the apparatus and method of the present invention, the circulating liquid may be water. Components entrained in the process gas during circulation may be mixed into the circulating liquid, and as a result, the circulating liquid may contain components such as ammonium sulfate.

[0045] In one embodiment, the ammonium sulfate content in the cooling circulating liquid is in the range of 0-5 wt.%, the ammonium sulfate content in the first stage is greater than the ammonium sulfate content in the second stage, and the ammonium sulfate content in the second stage is greater than the ammonium sulfate content in the third stage.

[0046] Preferably, the method of cooling a process gas of the present invention is performed by a cooling apparatus as described herein. Preferably, the cooling apparatus of the present invention is an apparatus used to perform the method of cooling a process gas as described herein. Various features described herein with respect to the cooling apparatus are also applicable to the method and vice versa. EXAMPLES

[0047] The following examples are provided to illustrate the present invention without limiting the scope of the present invention. Example 1 is a cooling device according to the present invention, which is shown in FIG. 1. Example 2 is a cooling device according to the present invention, which is shown in FIG. 2. A comparative example is shown in FIG. 3. The difference between FIG. 1 and FIG. 2 is mainly in the cold source and cooling mode. In FIG. 1, the first stage cooling and the second stage cooling are respectively that the circulating cooling water 5-1 cools the circulating liquid through the heat exchanger 4-1, and the low temperature process gas 9 cools the circulating liquid through the heat exchanger 4-2. In FIG. 2, the first stage cooling and the second stage cooling are respectively that the circulating liquid is cooled by the air cooler 4-4, and the circulating liquid is cooled by spray contact with the low temperature process gas 9. In FIG. 3, the cooling tower cools the circulating liquid only with the cold water 5-2 through the heat exchanger 4-3.

[0048] Example 1 As shown in Figure 1, process gas 1 (893,837 Nm3) was desulfurized by the ammonia-based method. 3 / h, 50°C) entered the first stage cooling zone 2-1 of the decarbonation cooling tower 2. The circulating liquid was pumped by the circulating pump 3-1 of the first stage cooling zone into the cooling tower for spraying and contacting with the process gas to cool the process gas to 42°C. The circulating liquid piping was provided with a heat exchanger 4-1, and the circulating liquid was cooled by the circulating cooling water 5-1. The temperature of the circulating liquid when it entered the tower was 38°C, and the temperature of the circulating liquid when it left the tower was 48°C. The temperature of the circulating cooling water when it entered the heat exchanger was 30°C, and the temperature of the circulating cooling water when it left the heat exchanger was 40°C.

[0049] The process gas after the first stage cooling entered the second stage cooling zone 2-2 through a liquid collector. The process gas was cooled to 39 ° C by spraying. The circulating liquid reached the gas heat exchanger 4-2 for heat exchange with the decarbonated process gas to reduce the temperature, and then returned to the second stage cooling zone 2-2 to cool the process gas. The temperature of the circulating liquid when it entered the tower was 30 ° C, and the temperature of the circulating liquid when it left the tower was 40 ° C. The temperature of the decarbonated process gas increased from 20 ° C to 31 ° C.

[0050] Then, the process gas after the second stage cooling entered the third stage cooling zone 2-3 through the liquid collector. The circulating liquid was cooled by the cold water 5-2 through the heat exchanger 4-3 and entered the tower for spraying to cool the process gas to 25 ° C. The temperature of the circulating liquid when it entered the tower was 20 ° C, and the temperature of the circulating liquid when it left the tower was 37 ° C. The temperature of the cold water when it entered the heat exchanger 4-3 was 7 ° C, and the temperature of the cold water when it left the heat exchanger 4-3 was 17 ° C.

[0051] The process gas was cooled in a cooling tower and then discharged to a decarbonation tower 7 via a flue 6, and the circulating liquid was brought into contact with the process gas via a circulation pump 8 to absorb carbon dioxide. The decarbonated process gas entered an ammonia leakage control system 12 via a flue 9, and a gas heat exchanger 4-2 was provided in the flue 9. The circulating liquid in the ammonia leakage control system was washed by a circulation pump 10 and brought into contact with the process gas to absorb free ammonia, and the process gas 11 after the ammonia removal was discharged via a process gas outlet.

[0052] The circulating cooling water consumption was 1890 t / h and the chilled water consumption was 1894 t / h.

[0053] The main process parameters of the cooling treatment in Example 1 are shown in Table 1.

[0054] [Table 1]

[0055] Example 2 As shown in Figure 2, process gas 1 (893,837 Nm3) was desulfurized by the ammonia-based method. 3 / h, 50°C) entered the first stage cooling zone 2-1 of the decarbonation cooling tower 2. The circulating liquid was pumped by the circulating pump 3-1 of the first stage cooling zone into the cooling tower for spraying and contacting with the process gas to cool the process gas to 42°C. An air cooler 4-4 was provided in the circulating liquid piping, and the circulating liquid was directly cooled by the air cooler 4-4. The temperature of the circulating liquid when it entered the tower was 38°C, and the temperature of the circulating liquid when it left the tower was 48°C.

[0056] The process gas after the first stage cooling reached the second stage cooling zone 2-2 through the liquid collector. The process gas was cooled to 32°C by spraying, and the circulating liquid reached the ammonia leakage control system 12 for heat exchange with the decarbonated process gas by spraying to reduce the temperature, and then returned to the second stage cooling zone 2-2 to cool the process gas. The temperature of the circulating liquid when it entered the cooling tower was 25°C, and the temperature of the circulating liquid when it left the cooling tower was 40°C. The temperature of the decarbonated process gas increased from 20°C to 35°C.

[0057] Then, the process gas after the second stage cooling enters the third stage cooling zone 2-3 through the liquid collector, and the circulating liquid is cooled by the cold water 5-2 through the heat exchanger 4-3 and enters the tower for spraying to cool the process gas to 25 ° C. The temperature of the circulating liquid when it enters the tower is 20 ° C, and the temperature of the circulating liquid when it leaves the tower is 30 ° C. The temperature of the cold water when it enters the heat exchanger 4-3 is 7 ° C, and the temperature of the cold water when it leaves the heat exchanger 4-3 is 17 ° C.

[0058] The process gas was cooled in the cooling tower and then discharged to the decarbonation tower 7 through the flue 6, and the circulating liquid was brought into contact with the process gas through the circulating pump 8 to absorb carbon dioxide. The decarbonated process gas entered the ammonia leakage control system 12 through the flue 9. The circulating liquid in the ammonia leakage control system was washed by the circulating pump 10 and brought into contact with the process gas to absorb free ammonia, and the process gas 11 after ammonia removal was discharged through the process gas outlet.

[0059] The chilled water consumption was 818 t / h.

[0060] The main process parameters for the cooling treatment in Example 2 are shown in Table 2.

[0061] [Table 2]

[0062] Comparative Example As shown in Figure 3, the process gas 1 (893,837 Nm3) desulfurized by the ammonia-based method 3 / h, 50 °C) entered the decarbonation cooling tower 2. The circulating liquid was cooled by cold water 5-2 via heat exchanger 4-3 and entered the tower for spraying to cool the process gas to 25 °C. The temperature of the circulating liquid when it entered the tower was 20 °C, and the temperature of the circulating liquid when it left the tower was 48 °C. The temperature of the cold water when it entered the heat exchanger 4-3 was 7 °C, and the temperature of the cold water when it left the heat exchanger 4-3 was 17 °C.

[0063] The chilled water consumption was 4267t / h.

[0064] Table 3 shows the main process parameters of the cooling treatment in the comparative example.

[0065] [Table 3]

[0066] The present invention further relates to the following embodiments. 1. A pre-cooling device before ammonia-based decarbonation, The first circulating liquid is used to circulate the process gas to T gas 1 a first stage cooling functional zone for cooling to a temperature of A second circulating liquid is used to circulate the process gas to T gas 2 a second stage cooling functional zone for cooling the first stage to a temperature of A third circulating liquid is used to circulate the process gas to T gas 3 a third cooling functional zone for cooling the mixture to a temperature of a first cold source for cooling a first circulating liquid; a second cold source for cooling the second circulating liquid; a third cold source for cooling the third circulating liquid; T gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas upon entering the first stage cooling zone, preferably T gas 0 is in the range of 40 to 80°C, and / or T gas 1 is in the range of 35 to 48°C, and / or T gas 2 is in the range of 15 to 40°C, and / or T gas 3 The pre-cooling device has three different cold sources, ranging from 10 to 30 degrees Celsius.

[0067] 2. The first cold source is circulating cooling water or cooling water from a closed cooling tower, and the first circulating liquid is cooled by a first heat exchanger, or the first cold source is air, and the first circulating liquid is cooled directly by an air cooler, and / or the second cold source is a decarbonated cold process gas and the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger, or the second circulating liquid is cooled by direct heat exchange via cross-spraying of the atomized liquid; and / or The pre-cooling device according to embodiment 1, wherein the third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device, and the third circulating liquid is cooled by a third heat exchanger, or the third circulating liquid is directly cooled by the cold source of the cooling device.

[0068] 3. A device or component that allows only gas to pass is provided between the cooling functional zones, and / or At least one layer of liquid distributor is provided in each cooling functional zone, the liquid distributor may be a trough distributor or a spray distributor; and / or The three functional zones may be combined in one tower or may exist as multiple towers; and / or 3. The pre-cooling device of embodiment 1 or 2, wherein the cooling device is part of an ammonia-based desulfurization and decarbonation system, an upstream of the cooling device is connected to the desulfurization device, and a downstream of the cooling device is connected to the decarbonation device, and the process gas comes from the desulfurization device and enters the decarbonation device after being cooled by the cooling device.

[0069] 4. The temperature of the first circulating liquid when it enters the tower is T liquid 1 and the temperature of the first circulating liquid when it leaves the column is T liquid 1’ and T liquid 1 <T liquid 1’ and T gas 0 -T liquid 1’ = ΔT 1 and preferably T liquid 1 is in the range of 10 to 40°C, and T liquid 1’ is in the range of 15 to 50°C, The temperature of the second circulating liquid when it enters the column is T liquid 2 and the temperature of the second circulating liquid when it leaves the column is T liquid 2’ and T liquid 2 <T liquid 2’ and T gas 1 -T liquid 2’ = ΔT 2 and preferably T liquid 2 is in the range of 15 to 36°C, and T liquid 2’ is in the range of 20 to 45°C, and The temperature of the third circulating liquid when it enters the column is T liquid 3 and the temperature of the third circulating liquid when it leaves the column is T liquid 3’ and T liquid 3 <T liquid 3’ and T gas 2 -T liquid 3’ = ΔT 3 and preferably T liquid 3 is in the range of 0 to 25°C, and T liquid 3’ is in the range of 10 to 40°C, ΔT 1 , ΔT 2 and ΔT 3 Each of the above is, independently of one another, 1°C or higher, preferably 2 to 15°C, and more preferably 2 to 5°C.

[0070] 5. The temperature of the first cold source is T before the heat exchange. source 1 After heat exchange, Tsource 1’ and T source 1 <T source 1’ and preferably T source 1 is in the range of 5 to 35°C, and T source 1’ is in the range of 10 to 45°C, The temperature of the second cold source is T source 2 After heat exchange, the temperature is T source 2’ and T source 2 <T source 2’ and preferably T source 2 is in the range of 10 to 30°C, and T source 2’ is in the range of 15 to 40°C, and The temperature of the third cold source is T source 3 After heat exchange, the temperature is T source 3’ and T source 3 <T source 3’ and preferably T source 3 is in the range of -17 to 10°C, and T source 3’ The pre-cooling device according to any one of embodiments 1 to 4, wherein the temperature is in the range of 0 to 30°C.

[0071] 6. A method for cooling a process gas, comprising: cooling the process gas to a temperature of 1000° C. using a first circulating liquid; gas 1A first cooling zone is used to cool the process gas to a temperature of T gas 2 A second cooling zone is used to cool the process gas to a temperature of T gas 3 and a third stage cooling functional zone for cooling the process gas to a temperature of Cooling a first circulating liquid using a first cold source; cooling the second circulating liquid using a second cold source; and cooling the third circulating liquid using a third cold source; T gas 3 <T gas 2 <T gas 1 <T gas 0 and T gas 0 is the initial temperature of the process gas upon entering the first stage cooling zone, preferably T gas 0 is in the range of 40 to 80°C, and / or T gas 1 is in the range of 35 to 48°C, and / or T gas 2 is in the range of 15 to 40°C, and / or T gas 3 The temperatures range from 10 to 30 degrees Celsius, and the three cold sources have different methods.

[0072] 7. The first cold source is circulating cooling water or cooling water from a closed cooling tower, and the first circulating liquid is cooled by a first heat exchanger, or the first cold source is air, and the first circulating liquid is cooled directly by an air cooler, and / or the second cold source is a decarbonated cold process gas and the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger, or the second circulating liquid is cooled by direct heat exchange via cross-spraying of the atomized liquid; and / or The method according to embodiment 6, wherein the third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device, and the third circulating liquid is cooled by a third heat exchanger, or the third circulating liquid is directly cooled by the cold source of the cooling device.

[0073] 8. The temperature of the first circulating liquid when it enters the tower is T liquid 1 and the temperature of the first circulating liquid when it leaves the column is T liquid 1’ and T liquid 1 <T liquid 1’ and T gas 0 -T liquid 1’ = ΔT 1 and preferably T liquid 1 is in the range of 10 to 40°C, and T liquid 1’ is in the range of 15 to 50°C, The temperature of the second circulating liquid when it enters the column is T liquid 2 and the temperature of the second circulating liquid when it leaves the column is T liquid 2’ and T liquid 2 <T liquid 2’ and T gas 1 -T liquid 2’ = ΔT 2 and preferably T liquid 2 is in the range of 15 to 36°C, and T liquid 2’ is in the range of 20 to 45°C, and The temperature of the third circulating liquid when it enters the column is T liquid 3 and the temperature of the third circulating liquid when it leaves the tower is T liquid 3’ and Tliquid 3 <T liquid 3’ and T gas 2 -T liquid 3’ = ΔT 3 and preferably T liquid 3 is in the range of 0 to 25°C, and T liquid 3’ is in the range of 10 to 40°C, ΔT 1 , ΔT 2 and ΔT 3 Each of the above is, independently of each other, 1°C or higher, preferably 2 to 15°C, more preferably 2 to 5°C.

[0074] 9. The temperature of the first cold source is T before the heat exchange. source 1 After the heat exchange, T source 1’ and T source 1 <T source 1’ and preferably T source 1 is in the range of 5 to 35°C, and T source 1’ is in the range of 10 to 45°C, The temperature of the second cold source is T source 2 After heat exchange, the temperature is T source 2’ and T source 2 <T source 2’ and preferably T source 2 is in the range of 10 to 30°C, and T source 2’ is in the range of 15 to 40°C, and The temperature of the third cold source is T source 3 After heat exchange, the temperature is T source 3’ and T source 3 <T source 3’ and preferably T source 3 is in the range of -17 to 10°C, and T source 3’ The method according to any one of embodiments 6 to 8, wherein the temperature is in the range of 0 to 30°C.

[0075] 10. The method according to any one of embodiments 6 to 9, wherein the cooling method is part of an ammonia-based desulfurization and decarbonation method, the upstream of the cooling method is a desulfurization process, and the downstream of the cooling method is a decarbonation process, the process gas comes from the desulfurization process and enters the decarbonation process after being cooled by the cooling method, and / or the ammonium sulfate content in the cooling circulation liquid is in the range of 0-5 wt.%, the ammonium sulfate content in the first stage is greater than the ammonium sulfate content in the second stage, and the ammonium sulfate content in the second stage is greater than the ammonium sulfate content in the third stage.

[0076] Although specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely examples, and that the scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes and modifications to these embodiments without departing from the principles and spirit of the present invention, and all such changes and modifications are included within the scope of the present invention. Furthermore, it should be understood by those skilled in the art that features described herein with respect to one or more embodiments may be combined with other embodiments, unless such combination is inconsistent with the purpose of the present invention. [Explanation of symbols]

[0077] In the drawings, the various reference symbols have the following meanings: Process Gas 1 Decarboxylation cooling tower 2 First stage cooling zone 2-1 (of a cooling tower) Second stage cooling zone 2-2 Third stage cooling zone 2-3 Circulation pump (for the first stage cooling zone of the cooling tower) 3-1 Circulation pump 3-2 (for the second stage cooling zone of the cooling tower) Circulation pump 3-3 (for the third stage cooling zone of the cooling tower) Heat exchanger 4-1 (in the first stage cooling zone of a cooling tower) Heat exchanger 4-2 (in the second stage cooling zone of a cooling tower) Heat exchanger 4-3 (in the third stage cooling zone of a cooling tower) Air cooler 4-4 Circulating cooling water 5-1 cold water 5-2 Process gas exhaust line (for cooling towers) 6 Decarbonation absorption tower 7 Circulation pump (for decarbonation absorption tower) 8 Process gas exhaust line (from the carbon dioxide absorber) 9 Circulation pump (for the water wash zone of the ammonia leak control system) 10. Process gas exhaust 11 Ammonia Leak Control System 12

Claims

1. A pre-cooling device before ammonia-based decarbonation, The first circulating liquid is used to circulate the process gas to T ｇａｓ １ a first stage cooling functional zone for cooling to a temperature of A second circulating liquid is used to circulate the process gas to T ｇａｓ ２ a second stage cooling functional zone for cooling to a temperature of A third circulating liquid is used to circulate the process gas to T ｇａｓ ３ a third cooling functional zone for cooling the water to a temperature of a first cold source for cooling the first circulating liquid; a second cold source for cooling the second circulating liquid; a third cold source for cooling the third circulating liquid; T ｇａｓ ３ <T ｇａｓ ２ <T ｇａｓ １ <T ｇａｓ ０ and T ｇａｓ ０ is the initial temperature of the process gas upon entering the first stage cooling functional zone; The three cold sources are different, a pre-cooling device.

2. the first cold source is circulating cooling water or cooling water from a closed cooling tower; and 2. The pre-cooling device of claim 1, wherein the first circulating liquid is cooled by a first heat exchanger.

3. the first cold source is air; and 2. The pre-cooling device of claim 1, wherein the first circulating liquid is directly cooled by an air cooler.

4. the second source of cold is a decarbonated low temperature process gas; and 2. The pre-cooling device of claim 1, wherein the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger, or the second circulating liquid is cooled by direct heat exchange via cross-spray of a spray liquid.

5. The third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device; and The pre-cooling device according to claim 1 , wherein the third circulating liquid is cooled by a third heat exchanger, or the third circulating liquid is directly cooled by a cold source of the cooling device.

6. A pre-cooling device according to any one of claims 1 to 5, wherein a device or component that allows only gas to pass is provided between the cooling functional zones.

7. At least one layer of liquid distributor is provided in each cooling functional zone; A pre-cooling device according to any one of claims 1 to 6, wherein the liquid distributor may be a trough distributor or a spray distributor.

8. A pre-cooling device according to any one of claims 1 to 7, wherein the three functional zones may be combined in one tower or may be present as several towers.

9. T ｇａｓ ０ is in the range of 40 to 80° C., and / or T ｇａｓ １ is in the range of 35 to 48° C., and / or T ｇａｓ ２ is in the range of 15 to 40° C., and / or T ｇａｓ ３ The pre-cooling device according to any one of claims 1 to 8, wherein the temperature is in the range of 10 to 30°C.

10. The temperature of the first circulating liquid when it enters the column is T ｌｉｑｕｉｄ １ and The temperature of the first circulating liquid when it leaves the column is T ｌｉｑｕｉｄ １’ and T ｌｉｑｕｉｄ １ <T ｌｉｑｕｉｄ １’ and T ｇａｓ ０ -T ｌｉｑｕｉｄ １’ = ΔT １ and The temperature of the second circulating liquid when it enters the column is T ｌｉｑｕｉｄ ２ and The temperature of the second circulating liquid when it leaves the column is T ｌｉｑｕｉｄ ２’ and T ｌｉｑｕｉｄ ２ <T ｌｉｑｕｉｄ ２’ and T ｇａｓ １ -T ｌｉｑｕｉｄ ２’ = ΔT ２ and The temperature of the third circulating liquid when it enters the column is T ｌｉｑｕｉｄ ３ and The temperature of the third circulating liquid when it leaves the column is T ｌｉｑｕｉｄ ３’ and T ｌｉｑｕｉｄ ３ <T ｌｉｑｕｉｄ ３’ and T ｇａｓ ２ -T ｌｉｑｕｉｄ ３’ = ΔT ３ and ΔT １ , ΔT ２ and ΔT ３ Each of the above, independently of each other, is 1° C. or higher, preferably 2-15° C., more preferably 2-5° C.

11. T ｌｉｑｕｉｄ １ is in the range of 10 to 40° C., and T ｌｉｑｕｉｄ １’ is in the range of 15 to 50° C., and / or T ｌｉｑｕｉｄ ２ is in the range of 15 to 36°C, and T ｌｉｑｕｉｄ ２’ is in the range of 20 to 45° C., and / or T ｌｉｑｕｉｄ ３ is in the range of 0 to 25°C, T ｌｉｑｕｉｄ ３’ The pre-cooling device according to claim 10, wherein the temperature is in the range of 10 to 40°C.

12. The temperature of the first cold source is T ｓｏｕｒｃｅ １ After the heat exchange, T ｓｏｕｒｃｅ １’ And T ｓｏｕｒｃｅ １ <T ｓｏｕｒｃｅ １’ and The temperature of the second cold source is T ｓｏｕｒｃｅ ２ After the heat exchange, T ｓｏｕｒｃｅ ２’ And T ｓｏｕｒｃｅ ２ <T ｓｏｕｒｃｅ ２’ and The temperature of the third cold source is T3 before the heat exchange and T4 after the heat exchange. ｓｏｕｒｃｅ ３’ And T ｓｏｕｒｃｅ ３ <T ｓｏｕｒｃｅ ３’ The pre-cooling device according to any one of claims 1 to 11,

13. T ｓｏｕｒｃｅ １ is in the range of 5 to 35°C, and T ｓｏｕｒｃｅ １’ is in the range of 10 to 45° C., and / or T ｓｏｕｒｃｅ ２ is in the range of 10 to 30° C., and T ｓｏｕｒｃｅ ２’ is in the range of 15 to 40° C., and / or T ｓｏｕｒｃｅ ３ is in the range of −17 to 10° C., and T ｓｏｕｒｃｅ ３’ The pre-cooling device according to claim 12, wherein the temperature is in the range of 0 to 30°C.

14. the cooling device is part of an ammonia-based desulfurization and decarbonation system; The upstream of the cooling device is connected to a desulfurization device, The downstream of the cooling device is connected to a decarbonation device; and A pre-cooling unit according to any one of claims 1 to 13, wherein the process gas comes from the desulfurization unit and enters the decarbonation unit after being cooled by the cooling unit.

15. 1. A method for cooling a process gas, the method comprising: The first circulating liquid is used to circulate the process gas to T ｇａｓ １ a first stage cooling functional zone for cooling to a temperature of A second circulating liquid is used to circulate the process gas to T ｇａｓ ２ a second stage cooling functional zone for cooling to a temperature of A third circulating liquid is used to circulate the process gas to T ｇａｓ ３ a third stage cooling functional zone for cooling the process gas to a temperature of cooling the first circulating liquid using a first cold source; cooling the second circulating liquid using a second cold source; and cooling the third circulating liquid using a third cold source; T ｇａｓ ３ <T ｇａｓ ２ <T ｇａｓ １ <T ｇａｓ ０ and T ｇａｓ ０ is the initial temperature of the process gas upon entering the first stage cooling functional zone; The three cold sources are different.

16. the first cold source is circulating cooling water or cooling water from a closed cooling tower; and 16. The method of claim 15, wherein the first circulating liquid is cooled by a first heat exchanger.

17. the first cold source is air; and 16. The method of claim 15, wherein the first circulating liquid is cooled directly by an air cooler.

18. the second source of cold is a decarbonated low temperature process gas; and 16. The method of claim 15, wherein the second circulating liquid is cooled by indirect heat exchange via a second heat exchanger, or the second circulating liquid is cooled by direct heat exchange via cross-spray of atomized liquid.

19. The third cold source is a cooling liquid, preferably the cooling liquid is obtained by a cooling device; and 16. The method of claim 15, wherein the third circulating liquid is cooled by a third heat exchanger or the third circulating liquid is cooled directly by a cold source of the cooling device.

20. T ｇａｓ ０ is in the range of 40 to 80° C., and / or T ｇａｓ １ is in the range of 35 to 48° C., and / or T ｇａｓ ２ is in the range of 15 to 40° C., and / or T ｇａｓ ３ The method according to any one of claims 15 to 19, wherein the temperature is in the range of 10 to 30°C.

21. The temperature of the first circulating liquid when it enters the column is T ｌｉｑｕｉｄ １ and the temperature of the first circulating liquid when it leaves the column is T ｌｉｑｕｉｄ １’ And T ｌｉｑｕｉｄ １ <T ｌｉｑｕｉｄ １’ and T ｇａｓ ０ -T ｌｉｑｕｉｄ １’ = ΔT １ and The temperature of the second circulating liquid when it enters the column is T ｌｉｑｕｉｄ ２ and the temperature of the second circulating liquid when it leaves the column is T ｌｉｑｕｉｄ ２’ And T ｌｉｑｕｉｄ ２ <T ｌｉｑｕｉｄ ２’ and T ｇａｓ １ -T ｌｉｑｕｉｄ ２’ = ΔT ２ and The temperature of the third circulating liquid when it enters the column is T ｌｉｑｕｉｄ ３ and the temperature of the third circulating liquid when it leaves the column is T ｌｉｑｕｉｄ ３’ And T ｌｉｑｕｉｄ ３ <T ｌｉｑｕｉｄ ３’ and T ｇａｓ ２ -T ｌｉｑｕｉｄ ３’ = ΔT ３ and ΔT １ , ΔT ２ and ΔT ３ Each of the above is, independently of each other, 1° C. or higher, preferably 2-15° C., more preferably 2-5° C.

22. T ｌｉｑｕｉｄ １ is in the range of 10 to 40° C., and T ｌｉｑｕｉｄ １’ is in the range of 15 to 50° C., and / or T ｌｉｑｕｉｄ ２ is in the range of 15 to 36° C., and T ｌｉｑｕｉｄ ２’ is in the range of 20 to 45° C., and / or T ｌｉｑｕｉｄ ３ is in the range of 0 to 25° C., and T ｌｉｑｕｉｄ ３’ The method according to claim 21, wherein the temperature is in the range of 10 to 40°C.

23. The temperature of the first cold source is Tsource1 before the heat exchange and T ｓｏｕｒｃｅ １’ And T ｓｏｕｒｃｅ １ <T ｓｏｕｒｃｅ １’ and The temperature of the second cold source is T ｓｏｕｒｃｅ ２ After the heat exchange, T ｓｏｕｒｃｅ ２’ And T ｓｏｕｒｃｅ ２ <T ｓｏｕｒｃｅ ２’ and The temperature of the third cold source before the heat exchange is T ｓｏｕｒｃｅ ３ After heat exchange, T ｓｏｕｒｃｅ ３’ And T ｓｏｕｒｃｅ ３ <T ｓｏｕｒｃｅ ３’ The method according to any one of claims 15 to 22, wherein

24. T ｓｏｕｒｃｅ １ is in the range of 5 to 35°C, and T ｓｏｕｒｃｅ １’ is in the range of 10 to 45° C., and / or T ｓｏｕｒｃｅ ２ is in the range of 10 to 30° C., and T ｓｏｕｒｃｅ ２’ is in the range of 15 to 40° C., and / or T ｓｏｕｒｃｅ ３ is in the range of −17 to 10° C., and T ｓｏｕｒｃｅ ３’ The method of claim 23, wherein the temperature is in the range of 0 to 30° C.

25. The cooling method is part of an ammonia-based desulfurization and decarbonation method, Upstream of the cooling method is a desulfurization process; Downstream of the cooling process is a decarbonation process, The method according to any one of claims 15 to 24, wherein the process gas comes from the desulfurization process and enters the decarbonation process after being cooled by the cooling method.

26. The ammonium sulfate content in the cooling circulating liquid is in the range of 0 to 5% by weight; 25. The method of any one of claims 15 to 24, wherein the ammonium sulfate content in the first stage is greater than the ammonium sulfate content in the second stage, and the ammonium sulfate content in the second stage is greater than the ammonium sulfate content in the third stage.

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