Patent Application
20220362706
This application claims priority under 35 U.S.C. § 119 of Chinese Patent Application No. 202110510852.5, filed on May 11, 2021, which is hereby incorporated in its entirety herein.
The disclosure relates to the technical field of environmental protection, and in particular, relates to apparatus and methods for removal of sulfur oxides and CO2 using ammonia.
Gas species in the air, such as CO2 and methane, may let shortwave solar radiation pass through, but can block longwave radiation from the earth surface to the cosmic space. With the increase of concentration of greenhouse gases such as CO2, the incident energy is greater than the escaping energy, leading to a temperature increase in the earth atmosphere, which is referred to as the greenhouse effect.
Carbon dioxide is the most important greenhouse gas, and the use of fossil fuels is a main discharge source thereof. The total CO2 discharge in China has ranked No. 1 in the world. Moreover, the energy structure in China with coal as the main source will continue for a while, and coal energy will still be the foundation for peak shaving with new energy and for energy security. China has promised to the world that it will peak carbon emissions by 2030 and achieve carbon neutrality by 2060. The capture, storage, and utilization of CO2 in flue gas play an important role in the control and reduction of greenhouse gas emission and in addressing the greenhouse effect and global warming issues.
At present, the mainstream carbon capture technology adopted is the amine method. Possible issues with amine method are high operating cost, and high discharge of wastes that is difficult to treat. New decarbonization technologies have been actively studied both in China and in other countries. Compared with the amine method, the ammonia method provides easy regeneration and low operating cost, and a decarbonization byproduct is ammonium bicarbonate fertilizer. Alternatively, part of the decarbonization circulating fluid may be regenerated to obtain CO2, which can be used for the production of downstream products such as urea, soda ash, polycarbonate, etc., and for enhanced oil recovery, beverage production, and welding, and injected back directly underground or into oceans. Ammonium bicarbonate is a typical compound multi-nutrient fertilizer that can provide nitrogen and CO2 to plants at the same time, which is particularly suitable for modern agriculture with soilless culture and plant growth in a greenhouse, providing CO2 reclamation and carbon recycling, and avoiding potential secondary pollution and environmental accidents caused by underground carbon storage. Compared with decarbonization using the amine method, ammonia provides high CO2 absorption efficiency, and the decarbonization product, ammonium bicarbonate, is easier to regenerate, which greatly lower the decarbonization cost.
However, ammonia is volatile, and decarbonization needs to take place under alkaline conditions, which increases ammonia slip (ammonia or one or more ammonia/amine bearing species that are derived from ammonia or ammonia/amine bearing species that were added to the gas flow, and that escape with the exhaust of the gas flow). Without solving these problems, ammonia slip may lead to higher decarbonization cost and secondary pollution.
Patent CN104707451A discloses a method for ammonia-based carbon capture and chemical synthesis from flue gas, which is implemented in a flue gas absorption and synthesis apparatus. The flue gas absorption and synthesis apparatus has a flue gas pipeline, an absorbing tower and a carbonization tower that are connected in parallel, an ammonia removing tower, and a solid-liquid separating device. Ammonia is used as an absorbing agent to capture CO2 in the flue gas, sodium sulfate is used as a transforming medium to produce chemical products such as sodium carbonate and sodium bicarbonate. For the ammonia-containing tail gas after decarbonization, a simple water washing method is used to remove ammonia, which leads to large ammonia slip.
CN201110039363.2 discloses a system and a process of using an ammonia-based process to capture and absorb sulfur dioxide and carbon dioxide under normal pressure, wherein desulfurization is performed first, followed by decarbonization, and a plurality of heat exchangers are provided in the desulfurization and decarbonization units to control the absorption temperature. At the same time, concentrated aqueous ammonia is used first for desulfurization and decarbonization, and dilute aqueous ammonia is then used for desulfurization and decarbonization. After the decarbonization, the gas is discharged directly. Absorption using ammonia at only low temperature and low concentration cannot satisfactorily reduce ammonia slip. In addition, aqueous ammonia of low concentration bring in a large amount of water, which inhibits the crystallization of ammonium sulfate and ammonium bicarbonate.
CN104874272A discloses an apparatus and a method of integrated desulfurization and carbon dioxide capture, wherein the SO2 in the flue gas is removed first in an ammonia desulfurization device, and then the flue gas is cooled in a direct contact cooling device before entering a decarbonization tower. After the decarbonization, the gas enters an ammonia washing tower that uses water for washing. After the washing, the flue gas enters a direct contact heating device, where some ammonia is removed in the spraying contact heating process. The aqueous solution discharged from the direct contact cooling tower is used as the spraying contact solution, and the solution after the direct contact spraying is cooled by the cooling tower and used for direct contact cooling spraying. The ammonia solution in the water washing tower enters the decarbonization tower for decarbonization or enters a stripping tower for ammonia removal. An acidic reagent, sulfuric acid, is added in the regeneration contact tower to enhance the ammonia washing. This method may have the following problems. Returning the water after direct water washing to decarbonization adds a lot of water into the decarbonization system, increasing the capital and operating cost. Further washing of ammonia consumes sulfuric acid. The process requires separate arrangements of a contact cooling device and a contact re-heating device, which leads to high capital and operating costs.
Therefore, it may be desirable to provide technology having features such as:
1. Good washing efficiency that is achieved by the use of acidic desulfurization absorbing fluid to wash ammonia-containing process gas;
2. The use of desulfurization circulating fluid to remove ammonia in the process gas after decarbonization and the direct use of the desulfurization circulating fluid after the washing for desulfurization, simplifying the process and realizing integrated desulfurization and decarbonization;
3. After ammonia washing, the direct use of ammonia-containing washing water as makeup water for desulfurization particulate scrubbing, to reduce desulfurization makeup water;
4. No need to separately provide a contact cooling device, which simplifies the process;
5. Condensate water that is circulated for use after membrane separation and purification, eliminating wastewater discharge;
6. Ammonium sulfate and ammonium bicarbonate fertilizers that are recovered, and decarbonization circulating fluid that may be regenerated, partially or wholly, to obtain Co2. The Co2 can be used for beverage production, enhanced oil recovery, welding, and the production of urea, soda ash, sodium bicarbonate, polycarbonate, polyurethane, food-grade CO2, CO2 gas fertilizer, potassium bicarbonate, and the like, which eliminates the need to inject all the Co2 back to underground for sequestration, truly realizing carbon emission reduction; and
7. Eliminating a need to control SO2 concentration at the outlet of a desulfurization functional area to be ≤2 ppm and removing sulfur oxides that are not removed in the desulfurization functional area in a decarbonization apparatus, lowering capital and operating cost of a desulfurization apparatus.
The objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
In
Apparatus and methods for ammonia-based desulfurization and decarbonization are provided. The apparatus and methods may use ammonia to remove sulfur oxides and CO2 to produce ammonium sulfate and ammonium bicarbonate fertilizers. The apparatus may include one or more of an ammonia-based desulfurization functional area, an ammonia-based decarbonization functional area, an ammonia washing functional area, an ammonium sulfate post-processing system, and an ammonium bicarbonate post-processing system. Ammonia may be used as a desulfurizing agent and a decarbonizing agent. A gas may first enter the desulfurization functional area for desulfurization to produce ammonium sulfate fertilizer. At least part of the desulfurization may be performed in a tower associated with the desulfurization functional area. The desulfurized gas may enter the decarbonization functional area for removal of carbon dioxide for the production of ammonium bicarbonate fertilizer. At least part of the decarbonization may be performed in a tower associated with the decarbonization functional area. The decarbonized gas may include free ammonia. The decarbonized gas may enter the ammonia washing functional area for washing with an ammonium sulfate solution for desulfurization, and then with water. At least part of the washing may be performed in a tower associated with the ammonia washing functional area. After the washing, the ammonia-containing ammonium sulfate solution and aqueous solution may be returned to the desulfurization functional area, where they may serve as an absorbing agent for desulfurization. The above functional areas may be combined in one tower or more than one tower. The above functional areas may be disposed in one tower or more than one tower. The above functional areas may include towers, such as a desulfurization tower associated with the desulfurization functional area, a decarbonization tower associated with the decarbonization functional area, and an ammonia washing tower associated with the ammonia washing functional area. The desulfurization functional area may be divided into a plurality of segments. The segments may include one or more of a cooling and concentrating segment, an absorbing segment, and a particulate removing segment. Each segment may be provided with at least one spraying layer. A device/part may be arranged between segments to allow a gas to pass. The particulate removing segment may be divided into two parts: for spray washing in the first part, an ammonium sulfate-containing concentrated solution may be used for circulated washing. An ammonium sulfate-containing dilute solution may be used in the second part for circulated washing. A device/part may be arranged between the two parts to allow a gas to pass. The concentration of the concentrated ammonium sulfate solution in the first part may be controlled at 5-40%, preferably 10-30%, and the pH may be controlled at 3-7, preferably 3-5.5. The concentration of the dilute ammonium sulfate solution in the second part may be controlled at 0.02-10%, preferably 0.03-5%, and the pH may be controlled at 3-7.
An ammonia-based desulfurization and decarbonization method may include the following steps, which may be performed in the order below:
1) using a desulfurization circulating fluid to remove part of SO2 in the process gas;
2) using a decarbonization circulating fluid to remove part of CO2 in the process gas; and
3) using a desulfurization circulating fluid to remove part of free ammonia in the process gas, and returning the desulfurization circulating fluid to a desulfurization apparatus.
Step 1) and step 2) may be followed by production of ammonium sulfate and ammonium bicarbonate fertilizers.
The CO2 removal efficiency in step 2) may be in the range 30-98%.
Part of the decarbonization circulating fluid may be sent to an ammonium bicarbonate post-processing apparatus to produce ammonium bicarbonate fertilizer, and/or part of the decarbonization circulating fluid may be sent to a CO2 regeneration apparatus to obtain gaseous CO2. The CO2 regeneration apparatus may include a regeneration tower. Part of the CO2 may be used for one or more of beverage production, enhanced oil recovery, and welding. Part of the CO2 may be used for production of one or more downstream products including urea, soda ash, sodium bicarbonate, polycarbonate, polyurethane, food-grade CO2, CO2 gas fertilizer, potassium bicarbonate, and the like.
The methods may include performing, between step 2) and step 3), a step 4) that may use process water to remove some or all of the free ammonia that may be present in the process gas. The methods may include performing, after step 3), a step 5) that may use process water to remove some or all of the free ammonia that may be present in the process gas.
The desulfurization circulating fluid may have a concentrated circulating fluid and an absorbing circulating fluid. The concentrated circulating fluid may have a pH of 1-6. The concentrated circulating fluid may have a pH of 2-4.5. The concentrated circulating fluid may have an ammonium sulfite concentration of 0-0.2%. The concentrated circulating fluid may have an ammonium sulfate concentration of 10-60%. The absorbing circulating fluid may have a pH of 4.5-6.5. The absorbing circulating fluid may have a pH of 4.8-6.2. The absorbing circulating fluid may have an ammonium sulfite concentration of 0.1-3%. The absorbing circulating fluid may have an ammonium sulfate concentration of 10-38%.
The decarbonization circulating fluid may have a pH of 7-13. The decarbonization circulating fluid may have a pH of 7.5-11. The decarbonization circulating fluid may have a pH of 8-9.5. The decarbonization circulating fluid may have an ammonium bicarbonate concentration of 3-40%. The decarbonization circulating fluid may have an ammonium bicarbonate concentration of 10-22%. The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 0.6-4. The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 1.2-3. The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 2-2.5.
The desulfurization absorption temperature may be in the range 5-55° C. The desulfurization absorption temperature may be in the range 15-50° C. The desulfurization absorption temperature may be in the range 20-40° C. The decarbonization absorption temperature may be in the range 0-45° C. The decarbonization absorption temperature may be in the range 5-40° C. The decarbonization absorption temperature may be in the range 10-30° C. A heat pump refrigeration technology may be used to provide cooling for cooling the decarbonization circulating fluid and the desulfurization circulating fluid. The temperature of the chilled water obtained by the heat pump may be in the range 3-25° C. The temperature of the chilled water obtained by the heat pump may be in the range 5-10° C.
Power for the heat pump may include one or more of hot water, steam, and electricity. Circulating water or desalted water may be used as a cold source. When desalted water is used, the desalted water after heat exchange may be sent to a low-temperature coal economizer to lower coal consumption per ton of steam.
The desulfurization functional area may be provided with a cooling apparatus to control the temperature of desulfurized flue gas in the range 5-55° C. The range may be 20-40° C. The ranges may meet temperature requirements for subsequent decarbonization. The cooling apparatus may be arranged on the circulating pipeline for the desulfurization circulating fluid to cool the desulfurization circulating fluid. After the cooling, the cooled desulfurization circulating fluid may further cool the desulfurized flue gas. A plurality of cooling apparatus may be provided, for example, on the circulating and absorbing pipeline in the absorbing segment and the particulate removing segment. Cooling apparatus may be provided on the water washing pipeline in the particulate removing segment. The washing condensate may be purified through membrane separation. The concentrated solution may enter the desulfurization absorbing area. The clean water may be used as makeup water for ammonia washing or may be used externally.
The cooling apparatus may be arranged in the process gas pipeline, at the inlet, inside of, or at the outlet of the desulfurization functional area. The circulating water or chilled water may be used as a cooling agent, which may be used individually or may be combined. The desulfurization circulating solution for ammonia washing may be taken from the circulating washing solution of the desulfurization tower and, after the ammonia washing, may be returned to the ammonia-based desulfurization functional area for desulfurization. The pH of the ammonium sulfate washing solution may be controlled at 2.5-7.5. The pH of the ammonium sulfate washing solution may be controlled at 3-5.5.
The pH for washing the process water may be controlled at 3-7. Part of the water solution absorbed during the ammonia washing circulation may enter, as makeup water, the circulating fluid for the particulate removing segment of the desulfurization tower. The ammonium sulfate concentration in the circulating solution may be controlled at 0-5%. The ammonium sulfate concentration in the circulating solution may be controlled at 0.02-2%.
Part of the water washing circulating solution may be pumped out and sent to a purification membrane separation apparatus. The produced purified water may be used as makeup water for the desulfurization and washing functional areas to control the ammonia concentration in the washing water and the concentration of the dilute ammonium sulfate solution for desulfurization and washing. The concentrated solution may enter the desulfurization absorption area.
The decarbonization functional area and the ammonia washing functional area may include one or a combination of a sprayer, a plate, and packed and floating-valve absorption columns.
The ammonium sulfate slurry produced from desulfurization may enter an ammonium sulfate post-processing system. After solid-liquid separation, wet ammonium sulfate may be dried and packed into an ammonium sulfate product. A wet ammonium sulfate product may be output directly. Solution from the solid-liquid separator may be returned to the desulfurization functional area. If an ammonium sulfate solution is produced, the solution may be evaporated and crystallized to form an ammonium sulfate slurry before entering the solid-liquid separation apparatus.
The ammonium bicarbonate slurry produced from the decarbonization tower may enter the solid-liquid separation apparatus. The solution may be returned to the decarbonization functional area. The wet ammonium bicarbonate may be dried and packed into a product. A wet ammonium bicarbonate product may be output directly. Part of the ammonium bicarbonate produced from the decarbonization may be heated to produce CO2 and an ammonia solution. The ammonia-containing solution may be returned to the decarbonization functional area for further use.
Main parameters of the desulfurization functional area may include:
Main parameters of the decarbonization functional area may include:
Main parameters of the ammonia washing functional area may include:
A strong acid, such as sulfuric acid, nitric acid, or hydrochloric acid, may be added into the desulfurization functional area and/or the ammonia washing functional area to adjust the pH of the circulating fluid.
The apparatus may include a heat pump system. Heat pump refrigeration technology may be used to provide cooling capacity for cooling the decarbonization circulating fluid and the desulfurization circulating fluid. The temperature of the chilled water obtained by the heat pump may be in the range 3-25° C. The temperature of the chilled water obtained by the heat pump may be in the range 5-10° C. The chilled water inlet/return pipelines may be connected with some or all chilling heat exchangers.
The apparatus may include a CO2 regeneration tower in which regeneration of decarbonization circulating fluid proceeds. CO2 regeneration tower operating parameters may include:
The apparatus may include one or more of a solution heat exchanger, a reboiler, a circulating water cooler, a chilled water cooler, a CO2 buffer tank, and a CO2 compressor.
The circulating pump for the decarbonization tower may output a part of the decarbonization circulating solution to a solution heat exchanger for heat exchange. The solution may then enter the CO2 regeneration tower. After the tower bottom is heated by steam from the reboiler, CO2 gas may be collected at the top of the tower. The gas may be subjected to two-stage cooling by the circulating water cooler and the chilled water cooler. The gas may then be sent to the CO2 buffer tank. After a certain period of buffering, the gas may be sent out for compression by the CO2 compressor. Condensate may be taken out from the bottom of the reboiler.
Process water may be added to an upper part of the CO2 regeneration tower.
After the CO2 obtained from regeneration is subjected to gas-liquid separation, part of the gas may be used for production of downstream products or enhanced oil recovery. The downstream products may include one or more of urea, soda ash, sodium bicarbonate, polycarbonate, food-grade CO2, CO2 gas fertilizer, potassium bicarbonate, and the like. Part of the gas may be used for one or more of enhanced oil recovery, beverage production, and welding. Part of the gas may be used for marine sequestration or underground sequestration. Separation liquid from the gas-liquid separation may be returned to the CO2 regeneration tower.
The apparatus and methods may include interaction between decarbonization and desulfurization processes. The apparatus and methods may include using an acidic desulfurization circulating fluid to wash ammonia. This may help achieve a high ammonia washing efficiency, and may reduce or eliminate ammonia slip during the decarbonization process. Ammonium bicarbonate output, the amount of sequestered CO2, and the output of CO2 downstream products may be flexibly adjusted.
By-product ammonia may be used in the process, thereby realizing treating wastes with wastes and a circular economy. Comparison between (a) the apparatus and methods; and (b) the calcium-based desulfurization/sodium-based desulfurization method+amine-based decarbonization+carbon sequestration device (also referred to as the “other approaches”):
The operating cost of the integrated desulfurization and decarbonization technology may be 50-60% lower than those of the calcium-based desulfurization+alkaline desulfurization+amine-based decarbonization.
Comparison between (a) ammonia-based desulfurization and decarbonization technology and (b) the calcium-based desulfurization+alkaline desulfurization+amine-based decarbonization technology
Technical metrics of the apparatus and methods may include:
Apparatus and methods for ammonia-based desulfurization and decarbonization are provided. The ammonia may be used to remove sulfur oxides and CO2 in process gas. The process gas may be fed into a desulfurization apparatus.
The methods may include (1) removing, using desulfurization circulating fluid, SO2 from the process gas. The methods may include (2) removing, using a decarbonization circulating fluid, CO2 from the process gas. The methods may include (3) removing, using desulfurization circulating fluid, free ammonia from the process gas. The methods may include returning the desulfurization circulating fluid to a desulfurization apparatus. The methods may include performing two or more of the aforementioned steps in the order presented.
The methods may include producing fertilizer. The fertilizer may include ammonium sulfate. The fertilizer may include ammonium bicarbonate.
The removing of CO2 may be performed such that a CO2 removal efficiency from 30-98% is achieved.
The methods may include producing from the decarbonization circulating fluid ammonium bicarbonate fertilizer. The methods may include regenerating gaseous CO2 from the decarbonization circulating fluid. The regenerating may be performed in a regeneration system that includes a CO2 regeneration tower having a tower bottom and a tower top.
An operating temperature at the tower bottom may be in a range from 90-150° C. The range may be from 100-130° C.
An operating temperature at the tower top may be in a range from 6-100° C. The range may be from 70-90° C.
A regeneration pressure at the tower bottom may be in a range from 0.2-0.7 MPa. The range may be from 0.3-0.5 MPa.
The methods may include flowing gas in the tower at a gas velocity in a range from 0.2-3 m/s. The range may be from 0.3-2 m/s.
The methods may include producing from the decarbonization circulating fluid ammonium bicarbonate fertilizer. The methods may include producing, from gaseous CO2 removed from the process gas, a downstream product.
The downstream product may include urea. The downstream product may include soda ash. The downstream product may include sodium bicarbonate. The downstream product may include polycarbonate. The downstream product may include CO2 gas fertilizer. The downstream product may include potassium bicarbonate. The downstream product may include food-grade CO2.
The methods may include enhanced oil recovery, with gaseous CO2 removed from the process gas.
The methods may include sequestering gaseous CO2 removed from the process gas. The sequestering may include performing marine sequestration. The sequestering may include performing underground sequestration.
The methods may include, between step 2 and step 3, removing, using process water, free ammonia from the process gas. The methods may include, after step 3, removing, using process water, free ammonia from the process gas.
The desulfurization circulating fluid may include a concentrated circulating fluid. The desulfurization circulating fluid may include an absorbing circulating fluid. The concentrated circulating fluid may have ammonium sulfite at a concentration of 0-0.2%. The concentrated circulating fluid may have ammonium sulfate at a concentration of 10-60%. The absorbing circulating fluid may have ammonium sulfite at a concentration of 0.1-3%. The absorbing circulating fluid may have ammonium sulfate at a concentration of 10-38%.
The concentrated circulating fluid may have a pH of 1-6. The concentrated circulating fluid may have a pH of 2-4.5.
The absorbing circulating fluid may have a pH of 4.5-6.5. The absorbing circulating fluid may have a pH of 4.8-6.2.
The decarbonization circulating fluid may have a pH of 7-13. The decarbonization circulating fluid may have a pH of 7.5-11. The decarbonization circulating fluid may have a pH of 8-9.5.
The decarbonization circulating fluid may have ammonium bicarbonate at a concentration of 340%. The decarbonization circulating fluid may have ammonium bicarbonate at a concentration of 10-22%.
The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 0.6-4. The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 1.2-3. The decarbonization circulating fluid may have an NH3/CO2 molar ratio of 2-2.5.
The desulfurization may include absorbing SO2 at a temperature in a range from 5-55° C. The desulfurization may include absorbing SO2 at a temperature in a range from 15-50° C. The desulfurization may include absorbing SO2 at a temperature in a range from 20-40° C.
The decarbonization may include absorbing CO2 at a temperature in a range from 0-45° C. The decarbonization may include absorbing CO2 at a temperature in a range from 5-40° C. The decarbonization may include absorbing CO2 at a temperature in a range from 10-30° C.
The apparatus may be configured to perform one or more steps of the methods.
The apparatus may include an ammonia-based desulfurization functional area that may be configured to apply a desulfurizing agent to a process gas. The desulfurization functional area may include a desulfurization tower. The apparatus may include an ammonia-based decarbonization functional area that may be configured to apply a decarbonizing agent to the process gas. The decarbonization functional area may include a decarbonization tower. The apparatus may include an ammonia washing functional area. The ammonia washing functional area may include an ammonia washing tower. The apparatus may include an ammonium sulfate post-processing system. The apparatus may include an ammonium bicarbonate post-processing system.
The desulfurizing agent may include ammonium. The decarbonizing agent may include ammonium. The desulfurization functional area may be configured to receive the process gas. The desulfurization functional area may be configured to desulfurize the process gas. The decarbonization functional area may be configured to receive the process gas after the process gas exits the desulfurization functional area. The decarbonization functional area may be configured to remove carbon dioxide from the process gas. The decarbonization functional area may be configured to produce an ammonium bicarbonate-containing material. The material may include a solution. The material may include a slurry. The ammonia washing functional area may be configured to receive process gas after the process gas exits the decarbonization functional area. The ammonia washing functional area may be configured to wash the process gas with a desulfurization circulating fluid. The ammonia washing functional area may be configured to wash the process gas with process water. The ammonia washing functional area may be configured to wash the process gas with process water after the ammonia washing functional area washes the process gas with a desulfurization circulating fluid. The ammonia washing functional area may be configured to wash the process gas with a desulfurization circulating fluid after the ammonia washing functional area washes the process gas with process water.
The desulfurization functional area may be configured to receive the process gas after the process gas exits the ammonia washing functional area. The desulfurization functional area may be configured to receive the process water after the process water exits the ammonia washing functional area. The desulfurization functional area may be configured to spray the process gas and the process water as an absorbing agent for desulfurization. The desulfurization functional area may be configured to receive ammonium sulfate-containing ammonium bicarbonate solution after the ammonium bicarbonate solution exits the decarbonization functional area.
The ammonia washing functional area may be configured to wash the process gas with the process water before washing the process gas with the desulfurization circulating fluid.
The ammonia-based desulfurization functional area, the ammonia-based decarbonization functional area, and the ammonia washing functional area may be disposed in a tower.
The desulfurization functional area may include a cooling and concentrating segment that may include a first spraying layer. The desulfurization functional area may include an absorbing segment. The absorbing segment may include a second spraying layer. The absorbing segment may be in fluid communication with the cooling and concentrating segment via a first device. The first device may be configured to allow gas to pass. The desulfurization functional area may include a particulate removing segment. The particulate removing segment may be in fluid communication with the absorbing segment via a second device. The second device may be configured to allow gas to pass. Each of the segments may include at least one spraying layer. Each of the segments may include a device that may be configured to allow gas to pass between the segments.
The apparatus may include, in the particulate removing segment, a first washing part configured to wash with concentrated, circulating ammonium sulfate-containing solution. The apparatus may include, in the particulate removing segment, a second washing part. The second washing part may be configured to wash with dilute, circulating ammonium sulfate-containing solution. The second washing part may be in fluid communication with the first washing part via a device that allows gas to pass.
The first part may be configured to maintain an ammonium sulfate concentration of the concentrated ammonium sulfate-containing solution in a range that is 10-38%. The first part may be configured to maintain an ammonium sulfate concentration of the concentrated ammonium sulfate-containing solution in a range that 12-30%. The first part may be configured to maintain a pH of the concentrated ammonium sulfate-containing solution in a range that is 2.5-7.5. The first part may be configured to maintain a pH of the concentrated ammonium sulfate-containing solution in a range that is 3-5.5.
The second part may be configured to maintain an ammonium sulfate concentration of the dilute ammonium sulfate-containing solution in a range that is 0-5%. The second part may be configured to maintain an ammonium sulfate concentration of the dilute ammonium sulfate-containing solution in a range that is 0.02-2%. The second part may be configured to maintain a pH of the dilute ammonium sulfate-containing solution in a range that is 3-7.
The desulfurization functional area may include a cooling apparatus. The cooling apparatus may be configured to maintain a temperature of process gas in a range that is 5-55° C. The range may be 15-50° C. The range may be 20-40° C.
The decarbonization functional area may include a cooling apparatus. The cooling apparatus may be configured to maintain a temperature of process gas in a range that is 0-45° C. The range may be 5-40° C. The range may be 10-30° C.
The apparatus may include a circulating pipeline. The circulating pipeline may be configured to transport desulfurization circulating fluid. The cooling apparatus may be arranged on the circulating pipeline. The cooling apparatus may be configured to cool spraying fluid. The cooling apparatus may be configured to cool circulating desulfurization fluid. The cooling apparatus may be configured to cool the process gas. The cooling apparatus may be configured to circulate water as a coolant.
The apparatus may include a process gas conduit. The cooling apparatus may be arranged on the process gas conduit. The cooling apparatus may be configured to cool the process gas.
The ammonia washing functional area may be configured to receive desulfurization fluid from the ammonia-based desulfurization functional area. The ammonia washing functional area may be configured to, using the desulfurization fluid, absorb ammonia from post-decarbonization process gas. The ammonia washing functional area may be configured to, after absorbing the ammonia, return the desulfurization fluid to the desulfurization functional area. The ammonia washing functional area may be configured to collect aqueous solution during ammonia washing. The ammonia washing functional area may be configured to provide the aqueous solution to the desulfurization functional area. The desulfurization functional area may be configured to use the returned desulfurization fluid to desulfurize the process gas. The desulfurization functional area may be configured to use the provided aqueous solution for particle removal. A pH of ammonium sulfate washing solution may be controlled at 2.5-7.5. The pH may be a pH of the solution in a washing part of the particulate removing segment. The washing part may be a first washing part. For example, the pH may be a pH of the solution in a desulfurization circulating tank of the desulfurization functional area, a washing circulating pump of the particulate removing segment of the desulfurization functional area, or any other suitable location.
An ammonia concentration in an ammonia washing circulating solution in the ammonia washing functional area may be controlled at 0-5%. An ammonia concentration in an ammonia washing circulating solution in the ammonia washing functional area may be controlled at 0-1%.
The apparatus may include a purification membrane separation apparatus. The apparatus may include a conduit. The particulate removing segment may be configured to provide dilute ammonium sulfate solution. The purification membrane separation apparatus may be configured to receive the dilute ammonium sulfate solution. The purification membrane separation apparatus may be configured to produce purified water from the dilute ammonium sulfate solution. The conduit may be configured to convey a fraction of the purified water to the ammonia washing functional area.
The ammonia washing functional area may be configured to use the purified water to replenish circulating washing water in the ammonia washing functional area.
The ammonia washing functional area may be configured to use the purified water to control a concentration of ammonia in the washing water.
The ammonia washing functional area may be configured to use the purified water to control a concentration of ammonium sulfate solution for return to the desulfurization functional area.
The conduit may include a first conduit. The fraction may include a first fraction. The apparatus may include a second conduit. The second conduit may be configured to convey concentrated solution to a desulfurization absorption area of the desulfurization functional area.
The apparatus may include an ammonium bicarbonate post-processing system. The decarbonization functional area may be configured to produce an ammonium bicarbonate slurry. The ammonium bicarbonate post-processing system may be configured to remove solution from the slurry. The ammonium bicarbonate post-processing system may be configured to pack the slurry into a product. The ammonium bicarbonate post-processing system may be configured to return the solution to the decarbonization functional area.
The apparatus may include a CO2 regeneration system. The CO2 regeneration system may be configured to heat ammonium bicarbonate from the decarbonization functional area to produce CO2. The CO2 regeneration system may be configured to heat ammonium bicarbonate from the decarbonization functional area to produce an ammonia solution. The CO2 regeneration system may be configured to provide the ammonia solution to the decarbonization functional area.
The ammonia-based desulfurization functional area may be configured to control a gas velocity at 0.5-5 m/s. The ammonia-based desulfurization functional area may be configured to control a gas velocity at 2-4 m/s. The ammonia-based desulfurization functional area may be configured to control a circulating fluid spraying density for a spray layer at 4-100 m3/m2-h. The ammonia-based desulfurization functional area may be configured to control a circulating fluid spraying density for a spray layer at 8-80 m3/m2-h. The ammonia-based desulfurization functional area may be configured to control a circulating fluid temperature at 5-55° C. The ammonia-based desulfurization functional area may be configured to control a circulating fluid temperature at 20-40° C. The ammonia-based desulfurization functional area may be configured to control a circulating fluid pH at 1-7. The gas velocity may be an empty tower gas velocity.
The ammonia-based decarbonization functional area may be configured to control a gas velocity at 2-4 m/s. The ammonia-based decarbonization functional area may be configured to control a gas temperature at 5-40° C. The ammonia-based decarbonization functional area may be configured to control a gas temperature at 10-30° C. The ammonia-based decarbonization functional area may be configured to control circulating fluid pH at 7-11. The gas velocity may be an empty tower gas velocity.
The ammonia washing functional area may be configured to control a velocity at 0.25-5 m/s. The ammonia washing functional area may be configured to control a gas temperature at 0-50° C. The ammonia washing functional area may be configured to control a temperature at 3-40° C. The ammonia washing functional area may be configured to control a circulating fluid pH at 3-10.
The apparatus may include a heat pump system. The heat pump system may be configured to receive water, at a temperature from 3-25° C., from a chilled water cooler that may be in thermal communication with the CO2. The heat pump system may be configured to receive water, at a temperature from 5-10° C., from a chilled water cooler that may be in thermal communication with the CO2. The heat pump system may be configured to return the chilled water to the chilled water cooler.
The apparatus may include a CO2 regeneration tower. The CO2 regeneration tower may be configured to extract CO2 from the process gas.
The CO2 regeneration tower may be configured to maintain a temperature of the process gas at a bottom of the tower at 90-150° C. The CO2 regeneration tower may be configured to maintain a temperature of the process gas at a bottom of the tower at 100-130° C.
The CO2 regeneration tower may be configured to maintain a temperature of the process gas at atop of the tower at 6-100° C. The CO2 regeneration tower may be configured to maintain a temperature of the process gas at a top of the tower at 70-90° C.
The CO2 regeneration tower may be configured to maintain a pressure of the process gas at a bottom of the tower at 0.2-0.7 MPa. The CO2 regeneration tower may be configured to maintain a pressure of the process gas at a bottom of the tower at 0.3-0.5 MPa.
The CO2 regeneration tower may be configured to maintain a gas velocity in the tower at 0.2-3 m/s. The CO2 regeneration tower may be configured to maintain a gas velocity in the tower at 0.3-2 m/s.
The apparatus may include a process water inlet. The inlet may be disposed on an upper part of the CO2 regeneration tower.
The apparatus may include a solution heat exchanger. The apparatus may include a reboiler. The apparatus may include a circulating water cooler. The apparatus may include a chilled water cooler in fluid communication with the circulating water cooler. The apparatus may include a CO2 buffer tank. The apparatus may include a CO2 compressor.
The decarbonization circulating pump may provide a fraction of the bicarbonate-containing material, via the solution heat exchanger, to the CO2 regeneration tower. The chilled water cooler may be configured to receive CO2, via the circulating water cooler, from the top of the tower. The CO2 compressor may be configured to receive CO2, via the CO2 buffer tank, from the chilled water cooler. The CO2 compressor may be configured to compress the CO2. The CO2 compressor may be configured to discharge the CO2.
The absorbing fluid and/or process gas may be cooled during desulfurization to prepare it for decarbonization. After the decarbonization, a desulfurization circulating fluid may be used for absorption of ammonia from the ammonia-containing process gas. After the absorption, the circulating fluid may be returned to a desulfurization functional area for desulfurization, thereby reducing the amount of ammonia added for desulfurization. After the decarbonization, fresh water may be used to wash the gas. Resultant ammonia-containing washing water may be returned, after the washing, to the desulfurization functional area to replenish washing water that is used to remove desulfurized particulates. Condensate produced from the particulate removing segment may be purified through membrane separation. Clean water may be used as makeup water for ammonia washing. Excess water may be discharged from the apparatus for external use.
Illustrative embodiments of apparatus and methods in accordance with the principles of the invention will now be described with reference to the accompanying drawings, which forma part hereof. It is to be understood that other embodiments may be utilized and that structural, functional and procedural modifications, additions or omissions may be made, and features of illustrative embodiments, whether apparatus or method, may be combined, without departing from the scope and spirit of the present invention.
All ranges and parameters disclosed herein shall be understood to encompass any and all subranges subsumed therein, every number between the endpoints, and the endpoints.
For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more (e.g. 1 to 6.1), and ending with a maximum value of 10 or less (e.g., 2.3 to 9.4, 3 to 8, 4 to 7), and finally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range.
Unless stated otherwise, %-concentrations are volume percentages for gas and weight percentages for liquid.
The ammonia-based desulfurization system may provide liquid that is sent to the tail gas washing system. The tail gas washing system may provide liquid that is sent to the ammonia-based desulfurization system.
The ammonia-based desulfurization system may provide ammonium sulfate.
The ammonia-based decarbonization system may exchange material with a CO2 regeneration system. The ammonia-based decarbonization system may provide ammonium bicarbonate.
The CO2 regeneration system may provide CO2 to a CO2 compressor. The CO2 compressor may provide CO2 to downstream products or processes. The CO2 compressor may provide CO2 to a pipe network.
In the apparatus shown in
Post-desulfurization tail gas 12 may enter the ammonia-based decarbonization system of decarbonization functional area 102 (shown in
Post-decarbonization tail gas 23 may enter the tail gas washing system of ammonia washing functional area 103 (shown in
In the apparatus shown schematically in
Process water 53 may be added to the upper part of CO2 regeneration tower 41. The apparatus may include heat pump system 50. The heat pump system may produce chilled water. Chilled water supply 54 may be sent to heat exchangers including desulfurization heat exchanger 4, desulfurization heat exchanger 11 (shown in
A coal-fired boiler flue gas (process gas) containing sulfur oxides and CO2 was introduced into an integrated desulfurization and decarbonization apparatus.
Process gas 1, which contained sulfur oxides and CO2, entered desulfurization tower 2 of desulfurization functional area 101. Desulfurization circulating pump 5 was used for spraying and circulation, by which the process gas was cooled while the ammonium sulfate solution was concentrated. The concentrated ammonium sulfate slurry with solid precipitation was sent via ammonium sulfate discharge pump 6 to ammonium sulfate solid-liquid separator 31. The solid was dried in the ammonium sulfate dryer 32, and packed in the ammonium sulfate packing machine 33 to obtain ammonium sulfate product 34. Circulating pump 3 in desulfurization functional area 101 and desulfurization circulating tank 13 were used for absorption spraying and circulation to absorb sulfur oxides (sulfur dioxide and sulfur trioxide) in the process gas, and the desulfurization heat exchanger 4 was used to control the desulfurization temperature. Desulfurization circulating pump 10 and desulfurization circulating water tank 9 were used for washing spraying and circulation, and desulfurization heat exchanger 11 was used to control the washing temperature and the temperature of the post-desulfurization tail gas 12. Flue gas condensate 14 was processed by membrane separation apparatus 15. Concentrated solution 16 obtained from membrane separation was returned to desulfurization tower 2. Purified water was obtained from the membrane separation. Part 18 of the purified water was used as makeup water for ammonia washing tower 25, and part 17 of the purified water was discharged. Ammonia 8 was metered and provided to desulfurization circulating tank 13 for ammonia addition. Oxidation air 7 was provided to desulfurization circulating tank 13 for oxidizing the solution.
Post-desulfurization tail gas 12 entered decarbonization tower 19 of decarbonization functional area 102. Decarbonization circulating pump 21 was used for absorption spraying and circulation, and a resulting slurry was sent by decarbonization discharge pump 22 to ammonium bicarbonate solid-liquid separator 37. The resulting solid was dried in ammonium bicarbonate drier 38, and packed in ammonium bicarbonate packing machine 39 to obtain ammonium bicarbonate product 40. Ammonia 24 was metered and provided to decarbonization tower 19 for ammonia addition. Part of the ammonium sulfate-containing ammonium bicarbonate solution was returned to desulfurization functional area 101.
Post-decarbonization tail gas 23 entered ammonia washing tower 25 of ammonia washing functional area 103. Ammonia washing tower circulating pump 26 was used for first-stage washing. First-stage washing fluid coming from acidic desulfurization fluid 35 of particulate washing circulating pump 20 of desulfurization circulating tank 13 was continuously added to ammonia washing tower 25. Desulfurization fluid 36, having absorbed ammonia, was returned to desulfurization circulating tank 13. Circulating pump 27 for the ammonia washing functional area 103 and circulating water tank 28 for the ammonia washing functional area 103 were used for second-stage washing. Second-stage washing fluid came from purified water 18. After the washing, wash drainage liquid 29 was returned to desulfurization functional area 101. After the washing, clean flue gas 30 was discharged.
99.6% anhydrous ammonia was used as an absorbing agent for desulfurization and decarbonization. Process gas (boiler flue gas) parameters are given in the table below:
The main parameters of the desulfurization system are given in the table below:
The main parameters of the decarbonization tower are given in the table below:
The main parameters of the tail gas after treatment by the ammonia washing tower are given in the table below:
A coal-fired boiler flue gas (process gas) containing sulfur oxides and CO2 was entered into an integrated desulfurization and decarbonization apparatus.
Process gas 1 containing sulfur oxides and CO2 entered desulfurization tower 2 of desulfurization functional area 101. Desulfurization circulating pump 5 was used for spraying and circulation, which cooled the process gas while concentrating the ammonium sulfate solution. The resulting concentrated ammonium sulfate slurry with solid precipitate was sent via ammonium sulfate discharge pump 6 to ammonium sulfate solid-liquid separator 31. The solid was dried in ammonium sulfate drier 32, and packed in ammonium sulfate packing machine 33 to obtain ammonium sulfate product 34. Circulating pump 3 in desulfurization functional area 101 and desulfurization circulating tank 13 were used for absorption spraying and circulation to absorb sulfur oxides (sulfur dioxide and sulfur trioxide) in the process gas, and desulfurization heat exchanger 4 was used to control the desulfurization temperature. Desulfurization circulating pump 10 and desulfurization circulating water tank 9 were used for washing spraying and circulation. Desulfurization heat exchanger 11 was used to control the washing temperature and the temperature of post-desulfurization tail gas 12. Flue gas condensate 14 was processed by membrane separation apparatus 15. Concentrated solution 16 obtained from membrane separation was returned to desulfurization tower 2. Purified water was obtained from the membrane separation. Part 18 of the purified water was used as makeup water for ammonia washing tower 25, and part 17 of the purified water was discharged. Ammonia 8 was metered and then provided to desulfurization circulating tank 13 as ammonia addition. Oxidation air 7 was provided to desulfurization circulating tank 13 for oxidizing the solution.
Post-desulfurization tail gas 12 entered decarbonization tower 19 of decarbonization functional area 102. Decarbonization circulating pump 21 was used for absorption spraying and circulation, and a resulting slurry was sent by decarbonization discharge pump 22 to ammonium bicarbonate solid-liquid separator 37. The resulting solid was dried in ammonium bicarbonate drier 38, and packed in ammonium bicarbonate packing machine 39 to obtain ammonium bicarbonate product 40. Ammonia 24 was metered and then provided to decarbonization tower 19 as ammonia addition. Part of the ammonium sulfate-containing ammonium bicarbonate solution was returned to desulfurization functional area 101.
Post-decarbonization tail gas 23 entered ammonia washing tower 25 of ammonia washing functional area 103. Circulating pump 26 for ammonia washing tower 25 was used for first-stage washing. First-stage washing fluid coming from acidic desulfurization fluid 35 of particulate washing circulating pump 20 of desulfurization circulating tank 13 was continuously added to ammonia washing tower 25. Desulfurization fluid 36, having-absorbed ammonia, was returned to desulfurization circulating tank 13. Circulating pump 27 for ammonia washing functional area 103 and circulating water tank 28 for ammonia washing functional area 103 were used for second-stage washing. Second-stage washing fluid came from purified water 18. After the washing, wash drainage liquid 29 was returned to desulfurization functional area 101. After the washing, clean flue gas 30 was discharged.
The apparatus included CO2 regeneration tower 41 in which the decarbonization circulating fluid was regenerated. Operating parameters of CO2 regeneration tower 41 were: 100-130° C. at tower bottom, 60-90° C. at tower top, an operating pressure of 0.3-0.4 MPa at tower bottom, and a gas velocity of 0.6-0.8 m/s.
The apparatus included solution heat exchanger 42, reboiler 43, circulating water cooler 44, chilled water cooler 45, CO2 buffer tank 46, and CO2 compressor 47.
Solution extracted at the outlet of decarbonization circulating pump 21 was sent to solution heat exchanger 42 before entering CO2 regeneration tower 41. The solution at the bottom of tower 41 was heated by steam in reboiler 43, and CO2 gas was collected at the top of tower 41. The gas was cooled in two-stage cooling by circulating water cooler 44 and chilled water cooler 45, before being sent to CO2 buffer tank 46. CO2 from buffer tank 46 was compressed by CO2 compressor 47, and subsequently 10% thereof was sent to CO2 downstream production apparatus 49 for production of polycarbonate, 5% was loaded into bottles or into tanker 48, and 85% was sent for sequestration.
Condensate 52 was taken out from the bottom of reboiler 43.
Process water 53 was added to the upper part of CO2 regeneration tower 41.
The apparatus included heat pump system 50. Heat pump system 50 produced chilled water. Chilled water supply 54 was sent to heat exchangers including chilled water cooler 45, desulfurization heat exchanger 4 and desulfurization heat exchanger 11 for the cooling of CO2 gas and circulating fluids. Chilled water return 55 was returned to heat pump system 50.
99.6% anhydrous ammonia was used as an absorbing agent for flue gas desulfurization and decarbonization for a 600 MW unit. Process gas (boiler flue gas) parameters are given in the table below:
The main parameters of the desulfurization system are given in the table below:
The main parameters of the decarbonization tower are given in the table below:
The main parameters of the tail gas after treatment by the ammonia washing tower are given in the table below:
The main parameters of the CO2 gas after regeneration by the CO2 regeneration tower and the two-stage cooling are given in the table below:
1. An ammonia desulfurization and decarbonization method using ammonia to remove sulfur oxides and CO2 in process gas, characterized in that the method sequentially comprises the following steps:
2. The method according to selected embodiment 1, characterized by at least one of the following:
3. The method according to selected embodiment 1, characterized in that the steps further comprise:
4. The method according to selected embodiment 1, characterized in that part of the gaseous CO2 is used for production of downstream products or oil displacement, the downstream products comprising urea, soda ash, sodium bicarbonate, polycarbonate, food CO2, CO2 gas fertilizer, potassium bicarbonate, and the like, and/or part of the CO2 is used for marine sequestration or underground sequestration.
5. The method according to selected embodiment 1, characterized in that the method further comprises step 4) between step 2) and step 3) in which process water is used to remove part of free ammonia in the process gas, and/or further comprises step 5) after step 3) in which the process water is used to further remove part of free ammonia in the process gas.
6. The method according to selected embodiment 1, characterized in that the desulfurization circulating fluid comprises a concentrated circulating fluid and an absorbing circulating fluid,
7. The method according to selected embodiment 1, characterized in that the decarbonization circulating fluid has a pH of 7-13, preferably 7.5-11, and more preferably 8-9.5, ammonium bicarbonate at a concentration of 3-40% and preferably 10-22%, and an NH3/CO2 molar ratio of 0.6-4, preferably 1.2-3, and more preferably 2-2.5.
8. The method according to selected embodiment 1, characterized in that the desulfurization absorption temperature is 5-55° C., preferably 15-50° C., and more preferably 20-40° C.; and the decarbonization absorption temperature is 0-45° C., preferably 5-40° C., and more preferably 10-30° C.
9. An apparatus for implementing the method according to any one of selected embodiments 1-8, characterized in that an ammonia desulfurization functional area, an ammonia decarbonization functional area, an ammonia washing functional area, an ammonium sulfate post-processing system, and an ammonium bicarbonate post-processing system are provided; ammonium is used as a desulfurizing and decarbonizing agent; process gas first enters the desulfurization functional area for desulfurization to produce an ammonium sulfate fertilizer; the desulfurized process gas enters the decarbonization functional area to remove carbon dioxide in the process gas and produce an ammonium bicarbonate-containing solution/slurry; the decarbonized process gas contains free ammonia and enters the ammonia washing functional area for washing with a desulfurization circulating fluid and then with the process water; after the washing, the ammonia-containing desulfurization solution and process water solution are returned to the desulfurization functional area and serve as an absorbing agent for desulfurization; and part of the ammonium sulfate-containing ammonium bicarbonate solution is returned to the desulfurization functional area.
10. The apparatus according to selected embodiment 9, characterized in that the ammonia washing functional area further comprises washing with the process water before washing with the desulfurization circulating fluid, and the ammonia desulfurization functional area, the ammonia decarbonization functional area, and the ammonia washing functional area are combined in one tower or multiple towers.
11. The apparatus according to selected embodiment 9, characterized in that the desulfurization functional area is divided into a plurality of segments, comprising a cooling and concentrating segment, an absorbing segment, and a particulate removing segment, each segment being provided with at least one spraying layer, and a device/part allowing gas to pass through being arranged between the segments.
12. The apparatus according to selected embodiment 11, characterized in that the particulate removing segment is divided into two parts; for spray washing in the first part, an ammonium sulfate-containing concentrated solution is used for circulated washing; an ammonium sulfate-containing dilute solution is used in the second part for circulated washing; and a device/part allowing gas to pass through is arranged between the two parts; the concentration of the concentrated ammonium sulfate solution in the first part is controlled at 10-38%, preferably 12-30%, and the pH is controlled at 2.5-7.5, preferably 3-5.5; and the concentration of the dilute ammonium sulfate solution in the second part is controlled at 0-5%, preferably 0.02-2%, and the pH is controlled at 3-7.
13. The apparatus according to selected embodiment 11, characterized in that the desulfurization functional area is provided with a cooling apparatus to control the temperature of desulfurized flue gas at 5-55° C., preferably 15-50° C., and more preferably 20-40° C.
14. The apparatus according to selected embodiment 11, characterized in that the decarbonization functional area is provided with a cooling apparatus to control the temperature of decarbonized flue gas at 0-45° C., preferably 5-40° C., and more preferably 10-30° C.
15. The apparatus according to selected embodiment 13, characterized by at least one of the following: the cooling apparatus is arranged on the circulating pipeline for the desulfurization circulating fluid to cool the spraying and circulating desulfurization fluid and to further cool the desulfurized flue gas; or the cooling apparatus is arranged on the process gas pipe/flue in the desulfurization functional area to directly cool the gas; and circulating water and/or chilled water is used as a cooling agent.
16. The apparatus according to selected embodiment 9, characterized by at least one of the following:
17. The apparatus according to selected embodiment 12, characterized in that part of the dilute ammonium sulfate solution is pumped out and sent to a purification membrane separation apparatus, the produced purified water is used as replenishing water for the deamination and washing functional area and the excess part is for external use to control the ammonia concentration in the washing water and the concentration of the dilute ammonium sulfate solution for desulfurization and washing, and the concentrated water enters a desulfurization absorption area.
18. The apparatus according to selected embodiment 9, characterized by at least one of the following:
19. The apparatus according to selected embodiment 9, characterized in that main parameters of the ammonia desulfurization functional area are as follows:
20. The apparatus according to selected embodiment 9, characterized in that main parameters of the decarbonization functional area are as follows:
21. The apparatus according to selected embodiment 9, characterized in that main parameters of the ammonia washing functional area are as follows:
22. The apparatus according to selected embodiment 9, further comprising a heat pump system, wherein the heat pump system provides the chilled water required for cooling, and the temperature of the chilled water obtained by the heat pump is 3-25° C., preferably 5-10° C.
23. The apparatus according to selected embodiment 9, further comprising a CO2 regeneration tower having a tower top and a tower bottom, wherein regeneration of the decarbonization circulating fluid proceeds in the CO2 regeneration tower.
24. The apparatus according to selected embodiment 23, characterized in that the operating parameters are as follows: the regeneration temperature is 90-150° C. and preferably 100-130° C. at tower bottom, and 6-100° C. and preferably 70-90° C. at tower top; the regeneration pressure is 0.2-0.7 MPa and preferably 0.3-0.5 MPa at tower bottom; and the regeneration tower gas velocity is 0.2-3 m/s and preferably 0.3-2 m/s.
25. The apparatus according to selected embodiment 23, characterized in that a process water inlet is provided on an upper part of the regeneration tower.
26. The apparatus according to selected embodiment 23, characterized in that the gaseous CO2 obtained by the regeneration tower is partially used for production of downstream products comprising urea, soda ash, sodium bicarbonate, polycarbonate, food CO2, CO2 gas fertilizer, potassium bicarbonate, and the like, partially used for oil displacement, beverage production, and gas welding, and partially used for marine sequestration or underground sequestration.
27. The apparatus according to selected embodiment 23, further comprising a solution heat exchanger, a reboiler, a circulating water cooler, a chilled water cooler, a CO2 buffer tank, and a CO2 compressor, wherein the decarbonization circulating pump outputs a part of the solution to the solution heat exchanger for heat exchange, the solution then enters the CO2 regeneration tower, the CO2 gas collected at the top of the tower is cooled by the coolers, then sent to the CO2 buffer tank, and is sent out after compression by the CO2 compressor.
Thus, apparatus and methods for desulfurization and decarbonization have been provided. Persons skilled in the art will appreciate that the present invention may be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation. The present invention is limited only by the claims that follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110510852.5 | May 2021 | CN | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17688091 | Mar 2022 | US |
| Child | 17709945 | US |
