Flue gas waste heat utilization and carbon capture integrated system
Technical Field
The invention relates to the technical field of flue gas pollutant purification treatment, in particular to a flue gas waste heat utilization and carbon capture integrated system.
Background
The mature carbon dioxide trapping technology applied in China is mainly a method for trapping after combustion, is more suitable for modifying and upgrading the existing boiler, and can treat a large amount of flue gas. Chemical absorption methods are the most widely used method in post-combustion trapping technology, depending on the trapping effect and the complexity of the process. The method realizes the separation of carbon dioxide by the chemical reaction of the absorbent and the carbon dioxide in the flue gas, and then realizes the release of the carbon dioxide and the regeneration of the absorbent by the reverse reaction. The technology is mature and reliable, and the purity of the extracted carbon dioxide is high. The rich liquor in the process needs to be heated, the lean liquor needs to be cooled, and the high-temperature regeneration gas needs to be cooled. Since the release of carbon dioxide and the regeneration of the absorbent require a large amount of steam, there is a problem of high energy consumption and low economy, and the prior art has not solved the problem for a while, which causes a certain resistance to the popularization of the carbon dioxide capture technology.
Disclosure of Invention
The invention aims to provide an integrated system for flue gas waste heat utilization and carbon capture, which can realize waste heat recovery and utilization during carbon dioxide capture recovery, is energy-saving and environment-friendly and reduces energy consumption of carbon dioxide capture.
The invention provides a flue gas waste heat utilization and carbon capture integrated system, which comprises an absorption tower, a lean-rich liquid heat exchanger, a regeneration tower, a reboiler and a first-stage first-class absorption heat pump;
the absorption tower comprises: a first inlet of the absorption tower, which is arranged at the lower part of the absorption tower; a second inlet of the absorption tower, which is arranged at the lower part of the absorption tower; the first outlet of the absorption tower is arranged at the lower part of the absorption tower;
the lean-rich liquid heat exchanger comprises: the first outlet of the lean-rich liquid heat exchanger is arranged at the upper part of the lean-rich liquid heat exchanger; the first inlet of the lean-rich liquid heat exchanger is arranged at the lower part of the lean-rich liquid heat exchanger; the second outlet of the lean-rich liquid heat exchanger is arranged at the lower part of the lean-rich liquid heat exchanger; the second inlet of the lean-rich liquid heat exchanger is arranged at the upper part of the lean-rich liquid heat exchanger;
the regeneration tower comprises: a regeneration tower first inlet arranged at the lower part of the regeneration tower; the first outlet of the regeneration tower is arranged at the upper part of the regeneration tower; the second inlet of the regeneration tower is arranged at the upper part of the regeneration tower; the second outlet of the regeneration tower is arranged at the lower part of the regeneration tower;
the reboiler comprises: a reboiler outlet and a reboiler inlet;
the first-stage absorption heat pump comprises: the first inlet of the first-stage first-type absorption heat pump, the first outlet of the first-stage first-type absorption heat pump and the second inlet of the first-stage first-type absorption heat pump;
the first inlet of the absorption tower is used for introducing flue gas, the first outlet of the absorption tower is connected with the first inlet of the lean-rich liquid heat exchanger, the second inlet of the absorption tower is connected with the first outlet of the first-stage first absorption heat pump, the first outlet of the lean-rich liquid heat exchanger is connected with the first inlet of the first-stage first absorption heat pump, the second outlet of the lean-rich liquid heat exchanger is connected with the first inlet of the regeneration tower, the second inlet of the lean-rich liquid heat exchanger is connected with the first outlet of the regeneration tower, the second inlet of the regeneration tower is connected with the outlet of the reboiler, the second outlet of the regeneration tower is connected with the inlet of the reboiler, and the second inlet of the first-stage first absorption heat pump is used for heat source entering.
Preferably, the regeneration tower further comprises a third outlet of the regeneration tower, the first-stage first-type absorption heat pump further comprises a third inlet of the first-stage first-type absorption heat pump and a third outlet of the first-stage first-type absorption heat pump, the third outlet of the regeneration tower is connected with the third inlet of the first-stage first-type absorption heat pump, and the third outlet of the first-stage first-type absorption heat pump is used for discharging regenerated gas.
Preferably, the first-stage first-type absorption heat pump further comprises a first-stage first-type absorption heat pump fourth inlet and a first-stage first-type absorption heat pump fourth outlet, the first-stage first-type absorption heat pump fourth inlet is used for heat supply network backwater, and the first-stage first-type absorption heat pump fourth outlet is used for heat supply network water supply.
Preferably, the absorption tower further comprises an absorption tower second outlet, the absorption tower second outlet is connected with the absorption tower first inlet, the absorption tower first outlet is connected to a pipeline between the absorption tower first outlet and the lean-rich liquid heat exchanger first inlet, and the absorption tower second inlet is used for a heat source to enter.
Preferably, the second-stage first-type absorption heat pump further comprises a second-stage first-type absorption heat pump third inlet and a second-stage first-type absorption heat pump third outlet, the second-stage first-type absorption heat pump third inlet is used for heat supply network backwater, and the second-stage first-type absorption heat pump third outlet is used for heat supply network water supply.
Preferably, the absorption tower further comprises a high-temperature flue gas heat exchanger and a heat exchanger, wherein the heat exchanger is arranged on a pipeline between the second outlet of the lean and rich liquid heat exchanger and the first inlet of the regeneration tower, and the high-temperature flue gas heat exchanger is used for recovering heat of high-temperature flue gas before entering the absorption tower and transferring the heat of the high-temperature flue gas to the heat exchanger for heating the part of heat of the rich liquid to be heated.
Preferably, the heat source is one or more of steam, gas and high temperature hot water.
Preferably, a third outlet of the first-stage absorption heat pump is connected with a carbon dioxide capture device.
Preferably, the reboiler is connected to a water supply line.
Preferably, a chimney is connected to the top of the absorption tower and used for discharging the treated flue gas.
Has the advantages that:
the invention combines the utilization of the waste heat of the flue gas and the capture of the carbon dioxide together, utilizes the high-temperature heat in the flue gas to heat the pregnant solution entering the regeneration tower so as to reduce the steam consumption of the regeneration tower, utilizes the first type of absorption heat pump to cool the barren solution entering the absorption tower and the regenerated gas at the outlet of the regeneration tower, not only meets the capture of the carbon dioxide, but also recovers the waste heat of the flue gas and reduces the emission of pollutants, and the heat of the flue gas is taken as a waste heat source to be introduced into the first type of absorption heat pump, and is transferred to a medium with the requirement of useful heat through the first type of absorption heat pump. And the heat is planned in a unified way, so that the energy conservation and the consumption reduction of the integrated system are realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic structural diagram of an integrated system for flue gas waste heat utilization and carbon capture in the invention.
Description of the reference numerals: 1-absorption tower, 101-first inlet of absorption tower, 102-second inlet of absorption tower, 111-first outlet of absorption tower, 112-second outlet of absorption tower, 2-barren and rich liquor heat exchanger, 211-first outlet of barren and rich liquor heat exchanger, 201-first inlet of barren and rich liquor heat exchanger, 212-second outlet of barren and rich liquor heat exchanger, 202-second inlet of barren and rich liquor heat exchanger, 3-regeneration tower, 301-first inlet of regeneration tower, 311-first outlet of regeneration tower, 302-second inlet of regeneration tower, 312-second outlet of regeneration tower, 313-third outlet of regeneration tower, 4-reboiler, 401-reboiler inlet, 411-reboiler outlet, 5-first class first absorption heat pump, 501-first class first inlet of first absorption heat pump 511-a first-stage first-type absorption heat pump first outlet, 502-a first-stage first-type absorption heat pump second inlet, 503-a first-stage first-type absorption heat pump third inlet, 513-a first-stage first-type absorption heat pump third outlet, 504-a first-stage first-type absorption heat pump fourth inlet, 514-a first-stage first-type absorption heat pump fourth outlet, 6-a second-stage first-type absorption heat pump, 601-a second-stage first-type absorption heat pump first inlet, 611-a second-stage first-type absorption heat pump first outlet, 602-a second-stage first-type absorption heat pump second inlet, 603-a second-stage first-type absorption heat pump third inlet, 613-a second-stage first-type absorption heat pump third outlet, 7-high-temperature flue gas heat exchanger, and 8-heat exchanger.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1
A flue gas waste heat utilization and carbon capture integrated system is shown in figure 1 and comprises an absorption tower 1, a lean rich liquor heat exchanger 2, a regeneration tower 3, a reboiler 4 and a first-stage first-type absorption heat pump 5; the first inlet 101 of the absorption tower is used for introducing flue gas, the first outlet 111 of the absorption tower is connected with the first inlet 201 of the lean-rich liquid heat exchanger, the second inlet 102 of the absorption tower is connected with the first outlet 511 of the first-stage first absorption heat pump, the first outlet 211 of the lean-rich liquid heat exchanger is connected with the first inlet 501 of the first-stage first-type absorption heat pump, the second outlet 212 of the lean-rich liquid heat exchanger is connected with the first inlet 301 of the regeneration tower, the second inlet 202 of the lean-rich liquid heat exchanger is connected with the first outlet 311 of the regeneration tower, the second inlet 302 of the regeneration tower is connected with the outlet 411 of the reboiler, the second outlet 312 of the regeneration tower is connected with the inlet reboiler 401, and the second inlet 502 of the first-stage first-type absorption heat pump is used for heat source entering. The regeneration tower 3 further comprises a third regeneration tower outlet 313, the first-stage first-type absorption heat pump 5 further comprises a third first-stage first-type absorption heat pump inlet 503 and a third first-stage first-type absorption heat pump outlet 513, the third regeneration tower outlet 313 is connected with the third first-stage first-type absorption heat pump inlet 503, and the third first-stage first-type absorption heat pump outlet 513 is used for discharging regeneration gas. The first-stage first-type absorption heat pump 5 further comprises a first-stage first-type absorption heat pump fourth inlet 504 and a first-stage first-type absorption heat pump fourth outlet 514, the first-stage first-type absorption heat pump fourth inlet 504 is used for heat supply network water return, and the first-stage first-type absorption heat pump fourth outlet 514 is used for heat supply network water supply. The flue gas waste heat utilization and carbon capture integrated system further comprises a second-stage first-class absorption heat pump 6, the second-stage first-class absorption heat pump 6 comprises a first inlet 601 of the second-stage first-class absorption heat pump, a first outlet 611 of the second-stage first-class absorption heat pump, a second inlet 602 of the second-stage first-class absorption heat pump, the absorption tower further comprises a second outlet 112 of the absorption tower, the second outlet 112 of the absorption tower is connected with the first inlet 601 of the second-stage first-class absorption heat pump, the first outlet 611 of the second-stage first-class absorption heat pump is connected to a pipeline between the first outlet 111 of the absorption tower and the first inlet 201 of the lean-rich liquid heat exchanger, and the second inlet 602 of the second-stage first-class absorption heat pump is used for heat source entering. The second-stage first-type absorption heat pump 6 further comprises a second-stage first-type absorption heat pump third inlet 603 and a second-stage first-type absorption heat pump third outlet 613, the second-stage first-type absorption heat pump third inlet 603 is used for heat supply network water return, and the second-stage first-type absorption heat pump third outlet 613 is used for heat supply network water supply. The absorption tower further comprises a high-temperature flue gas heat exchanger 7 and a heat exchanger 8, wherein the heat exchanger 8 is arranged on a pipeline between the second outlet 212 of the lean-rich liquid heat exchanger and the first inlet 301 of the regeneration tower, the high-temperature flue gas heat exchanger 7 is used for recovering heat of high-temperature flue gas before entering the absorption tower 1, and the heat of the high-temperature flue gas is transferred to the heat exchanger 8 to be used for heating the part of heat of the rich liquid needing to be heated. The heat source is steam, fuel gas and high-temperature hot water, the third outlet 513 of the first-stage first-class absorption heat pump is connected with a carbon dioxide compressor, the reboiler 4 is connected with a water supply pipe, the top of the absorption tower 1 is connected with a chimney, and the chimney is used for discharging the treated flue gas.
The working and using processes are as follows:
the method comprises the following steps of arranging a high-temperature flue gas heat exchanger 7 between a boiler and an absorption tower 1, recovering high-temperature flue gas heat in front of the absorption tower 1, transferring the part of heat to the heat exchanger for heating rich liquid needing to be heated in carbon dioxide capture to reduce steam consumption of a regeneration tower 3, cooling flue gas by the absorption tower 1, raising the temperature of a circulating medium after passing through the absorption tower 1, recovering the heat of the flue gas after cooling the flue gas by the circulating medium of the absorption tower 1, dividing the circulating medium into two paths after absorbing the flue gas heat by the absorption tower 1, taking one path as a waste heat source to enter a second-stage first-class absorption heat pump 6, extracting the heat by the second-stage absorption heat pump 6, then entering the regeneration tower 3 through a lean rich liquid heat exchanger 2, and performing a carbon dioxide release process according to process requirements; and the other path of the carbon dioxide passes through a lean-rich liquid heat exchanger 2 and then enters a regeneration tower 3, and the release process of the carbon dioxide is carried out according to the process requirement. The lean solution to be cooled and the regenerated gas to be cooled are directly introduced into an absorber and a condenser of the first-class absorption heat pump 5, the lean solution after being cooled enters the absorption tower 1 after passing through the first-class absorption heat pump 5, and the regenerated gas after being cooled enters a subsequent trapping device. The process saves the space for placing the equipment, simplifies the process flow and improves the system efficiency. The first-class absorption heat pump 5 extracts the heat of the flue gas, the heat of the lean solution to be cooled and the heat of the regenerated gas to be cooled, and the heat is transferred to return water of a heat supply network, process water, domestic water or other media to be heated, which enter an absorber of the first-class absorption heat pump 5 and a condenser, through self operation, so that the waste heat utilization is realized, and the integral energy consumption of the integrated system is saved. After the flue gas passes through the absorption tower 1, the flue gas is cooled by the low temperature circulating medium, and the flue gas can produce certain condensation phenomenon, and in the condensation process, pollutants such as a certain amount of smoke and dust, sulfur dioxide can be taken away by the condensate water in the flue gas, and flue gas pollutant index can obviously be less than the emission index of not using the integration system.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.