Flue gas dehydration and heat recovery device

Abstract

The utility model relates to the technical field of flue gas treatment, in particular to a flue gas dehydration and heat recovery device. Comprising a dehydrating tower, a first-section circulating pump, a first-section circulating cooler, a second-section circulating pump and a second-section circulating cooler, the dehydrating tower is provided with two dehydrating sections including a primary dehydrating condensation section and a deep dehydrating condensation section, the primary dehydrating condensation section is located below the deep dehydrating condensation section, and an oil collecting tank is arranged between the two dehydrating condensation sections; a first feeding hole is formed in one side of the bottom of the dehydrating tower and is used for receiving denitrated flue gas, a first discharging hole is formed in the top of the dehydrating tower, and the first discharging hole is connected with a downstream gypsum process desulfurization unit. The dehydrating tower is arranged, so that moisture and heat in the flue gas can be recovered at the same time, and the temperature of the flue gas before desulfurization is greatly reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to flue gas treatment technical field especially, it is a kind of flue gas dehydration and heat recovery device. BACKGROUND

[0002] A large amount of high-temperature flue gas will be generated during the operation of a boiler, and the flue gas contains not only N2, water and other main components, but also harmful components such as SO2 and nitrogen oxides, as well as a large amount of dust. Direct discharge will not only cause great harm to the environment, but also cause the moisture and heat in the flue gas to be lost to the environment. The mainstream process usually adopts SCR denitration technology and wet desulfurization technology in combination with dust removal technology to purify and treat the flue gas, so as to ensure that the treated flue gas meets the emission standard. The operation sequence of denitration first and then desulfurization is usually adopted.

[0003] Coal itself contains about 10% moisture, and new moisture is generated during the combustion process. The water content in the flue gas can reach up to 18%. After desulfurization, a large amount of water in a saturated state is discharged with the flue gas and lost to the atmosphere. At the same time, the flue gas encounters cold at the outlet of the chimney and forms white smoke plume. In addition, the temperature of the flue gas after denitration is still as high as 160-180℃. The excessively high temperature leads to a decrease in the subsequent SO2 absorption efficiency, which is not conducive to the desulfurization process and requires that the desulfurization tower must increase the circulation amount for flue gas cooling.

[0004] Therefore, it is necessary to develop a process system to optimize the existing flue gas treatment process, recover the moisture and heat carried out by flue gas emission, eliminate white smoke plume, and reduce the temperature of flue gas before desulfurization to improve the desulfurization efficiency.

[0005] Chinese patent publication No. CN110575735A discloses a flue gas dehydration and white elimination system, which is provided with a dehydration tower. The dehydration tower is used to adsorb the moisture in the flue gas by installing a 3A molecular sieve filler layer and an activated carbon filler layer in the dehydration tower according to the adsorption principle, so as to realize flue gas dehydration. The adsorbent is regenerated by using a vacuum desorption device, and the adsorbed moisture is recovered.

[0006] Chinese patent publication No. CN211411555U discloses a flue gas dehydration and white elimination system, which is provided with an evaporator and a cooler above the desulfurization tower according to the principle of indirect heat exchange. The evaporator is used to absorb the heat of flue gas and condense saturated water vapor at the same time, so that the water vapor condenses into low-temperature water droplets and falls freely. The coolant after heat absorption is pressurized and heated and then enters the cooler. In the cooler, the coolant releases heat to heat the low-temperature flue gas, so as to increase the unsaturation degree of the moisture in the flue gas and achieve the effect of eliminating white smoke plume.

[0007] The above-mentioned patents all reduce the water content in the flue gas by different principles, and to some extent, realize the recovery of moisture. However, the effect of flue gas cooling is not obvious, and there are problems such as the need to regenerate the adsorbent and low dehydration efficiency in the adsorption and indirect heat exchange process. The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0008] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0009] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0010] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0011] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0012] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0013] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0014] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0015] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0016] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0017] The utility model discloses a kind of smoke dehydration and heat recovery devices, which are characterized by the following technical solutions.

[0018] 1. The utility model discloses overcome the current device moisture loss big, high temperature flue gas leads to low desulfurization efficiency etc. shortcoming, adopt direct heat exchange technical means, set up dehydration tower, recovered the moisture and heat in flue gas, eliminated white smoke plume, reduced the flue gas temperature after denitration simultaneously, improved the follow-up desulfurization efficiency.

[0019] 2. The utility model discloses through one section circulating pump, one section circulating cooler, two section circulating pump and two section circulating cooler constitute the circulating heat exchange system of the circulation, can effectively take out the heat of absorption liquid absorption. High temperature absorption liquid is cooled in circulating cooler, and the heat of absorption can be according to actual demand to reuse, play the role of energy saving and water saving, improved the energy utilization efficiency of whole device, reduced energy waste, met the requirement of energy saving and emission reduction.

[0020] 3. The utility model discloses through setting liquid distributor above every section bower ring filler, ensured the uniform distribution of absorption liquid in filler layer, made gas-liquid contact more uniform and stable, avoided the situation of uneven heat exchange or low mass transfer efficiency, guaranteed the stability and reliability of whole dehydration tower operation.

[0021] 4. The utility model discloses two stage dehydration tower design, combines direct heat exchange principle, in primary dehydration condensation section, flue gas and absorption liquid first contact heat exchange, a large amount of heat is taken away by absorption liquid, and flue gas temperature reduces significantly, and part of water vapor begins to condense. Further depth treatment in depth dehydration condensation section makes flue gas final temperature can be reduced to the range suitable for desulfurization greatly, effectively solved the problem that flue gas temperature is too high before desulfurization in traditional process influences desulfurization efficiency, and can realize higher dehydration efficiency, reduce the water content in flue gas, reduce the possibility of white smoke plume formation. DRAWINGS

[0022] Figure 1 It is the structure schematic drawing of the utility model.

[0023] Reference signs

[0024] 1-dehydration tower, 2-liquid distributor, 3-oil collecting tank, 4-third discharge port, 5-first discharge port, 6-one section circulating pump, 7-one section circulating cooler, 8-two section circulating pump, 9-two section circulating cooler, 10-first feed port, 11-second discharge port, 12-second feed port, 13-third feed port. DETAILED DESCRIPTION

[0025] The utility model will be further described in the following in conjunction with the drawings and through specific embodiment, the following embodiment is only descriptive, is not limitative, can not be defined the protection scope of the utility model with this.

[0026] The device for flue gas dewatering and heat recovery comprises a dewatering tower 1, a first circulating pump 6, a first circulating cooler 7, a second circulating pump 8 and a second circulating cooler 9, the dewatering tower 1 is provided with two-stage dewatering structure and is divided into a primary dewatering condensing section and a deep dewatering condensing section, the primary dewatering condensing section is located below the deep dewatering condensing section, and an oil collecting tank 3 is arranged between the primary dewatering condensing section and the deep dewatering condensing section; a first feeding port 10 is arranged at the bottom of the dewatering tower 1 and is used for receiving flue gas after denitration, and a first discharging port 5 is arranged at the top of the dewatering tower 1 and is connected with a downstream gypsum method desulfurization unit;

[0027] A second feeding port 12 is further arranged at the middle section of the dewatering tower 1, a second discharging port 11 is arranged at the bottom of the dewatering tower 1 and is connected with the inlet end of the first circulating pump 6, the first outlet end of the first circulating pump 6 is connected with the inlet end of the first circulating cooler 7, and the outlet end of the first circulating cooler 7 is connected with the second feeding port 12, so that the cooled absorption liquid is returned to the primary dewatering condensing section;

[0028] A third feeding port 13 is arranged at the top of the dewatering tower 1, a third discharging port 4 is arranged at the middle section of the dewatering tower 1 and is connected with the inlet end of the second circulating pump 8, the outlet end of the second circulating pump 8 is connected with the inlet end of the second circulating cooler 9, and the first outlet end of the second circulating cooler 9 is connected with the third feeding port 13, so that part of the cooled absorption liquid is returned to the deep dewatering condensing section.

[0029] The second outlet end of the second circulating cooler 9 is connected with the second feeding port 12.

[0030] The second outlet end of the first circulating pump 6 is used for water recovery.

[0031] Pall ring fillers are arranged in the primary dewatering condensing section and the deep dewatering condensing section, in the dewatering tower 1, flue gas flows from bottom to top, absorption liquid is uniformly distributed through a liquid distributor 2, the uniform distribution of the absorption liquid on the pall ring fillers is ensured, and gas-liquid two-phase is fully contacted and heat-exchanged in the pall ring fillers.

[0032] In the embodiment of the utility model, the absorption liquid and the flue gas are directly heat-exchanged and absorbed, on one hand, the flue gas temperature is reduced, which is more conducive to the subsequent desulfurization process, on the other hand, the water content in the flue gas is reduced, the water in the flue gas is recovered, the role of water saving is played, and the low-temperature heat carried in the recovered water can be used for heating, preheating and the like.

[0033] After being treated by the dewatering tower 1, the flue gas after denitration is reduced from 170 DEG C to 40 DEG C, which is more conducive to the subsequent desulfurization process, and the water content in the flue gas is reduced from 13% to below 5%, not only a large amount of hot water is recovered, but also the white smoke plume is eliminated.

[0034] Working principle:

[0035] The 170℃ flue gas after denitration (about 13% water content) enters the primary dewatering condensing section of the dewatering tower through the first feed port on the bottom side. In the primary dewatering condensing section, the rising flue gas is in countercurrent contact with the absorption liquid uniformly distributed on the Pall ring packing from the top through the liquid distributor. The heat in the flue gas is rapidly transferred to the absorption liquid, the temperature of the absorption liquid is increased, the temperature of the flue gas is greatly reduced, and the water vapor in the flue gas begins to condense into liquid water in large quantities, realizing the primary gas-water separation.

[0036] The high-temperature absorption liquid absorbing the heat converges to the bottom under the action of gravity and flows out through the second discharge port, is extracted by the primary circulating pump, and is partially transported to the primary circulating cooler and the other part is used to recover the water in the flue gas. In the primary circulating cooler, the absorption liquid exchanges heat with the circulating water and is cooled to a suitable temperature (about 45℃). The cooled absorption liquid returns to the primary dewatering condensing section through the second feed port and continues to participate in the heat exchange process with the flue gas, so as to repeatedly circulate and absorb the heat of the flue gas and timely remove the heat by the circulating water.

[0037] The flue gas after the primary dewatering condensing section continues to rise and enters the deep dewatering condensing section. In this section, the flue gas is also in countercurrent contact with the absorption liquid uniformly distributed on the Pall ring packing from the top through the liquid distributor. Since the temperature of the absorption liquid in this section is relatively low (cooled by the secondary circulating cooler), the flue gas is further condensed.

[0038] Finally, the low-temperature flue gas after dewatering (about 40℃) is discharged through the first discharge port at the top and sent to the downstream gypsum desulfurization unit for subsequent treatment; and the water condensed and recovered in the tower bottom and the circulating process can be collected, purified and used for heating or preheating of other process materials, realizing the effective recovery and utilization of the heat and water in the flue gas, greatly reducing the temperature of the flue gas before desulfurization and improving the comprehensive benefits of the entire flue gas treatment system.

[0039] Although the embodiments and drawings of the utility model are disclosed for the purpose of illustration, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the utility model and the appended claims, therefore, the scope of the utility model is not limited to the content disclosed in the embodiments and drawings.

Claims

1. A flue gas dehumidification and heat recovery device, characterized by: The device comprises a dehydration tower, a first circulation pump, a first circulation cooler, a second circulation pump and a second circulation cooler, the dehydration tower is provided with two dehydration sections, which are a primary dehydration condensing section and a deep dehydration condensing section, the primary dehydration condensing section is located below the deep dehydration condensing section, and an oil collection tank is arranged between the two dehydration condensing sections; a first feeding port is arranged on one side of the bottom of the dehydration tower for receiving flue gas after denitration, a first discharging port is arranged on the top of the dehydration tower, and the first discharging port is connected with a downstream gypsum method desulfurization unit; a second feeding port is further arranged on the middle section of the dehydration tower, a second discharging port is arranged on the bottom of the dehydration tower, the second discharging port is connected with the inlet end of the first circulation pump, the first outlet end of the first circulation pump is connected with the inlet end of the first circulation cooler, and the outlet end of the first circulation cooler is connected with the second feeding port, so that the cooled absorption liquid is returned to the primary dehydration condensing section; a third feeding port is arranged on one side of the top of the dehydration tower, a third discharging port is arranged on the middle section of the dehydration tower, the third discharging port is connected with the inlet end of the second circulation pump, the outlet end of the second circulation pump is connected with the inlet end of the second circulation cooler, and the outlet end of the second circulation cooler is connected with the third feeding port, so that the cooled absorption liquid is returned to the deep dehydration condensing section.

2. The flue gas dehydrating and heat recovering device according to claim 1, characterized in that: The second outlet end of the first circulation pump is used for extracting water.

3. The flue gas dehydrating and heat recovering device according to claim 1, characterized in that: The second outlet end of the second circulation cooler is connected with the second feeding port.

4. The flue gas dehydrating and heat recovering device according to claim 1, characterized in that: Pall ring fillers are arranged in the primary dehydration condensing section and the deep dehydration condensing section.

5. The flue gas dehydrating and heat recovering device according to claim 4, characterized in that: Liquid distributors are arranged above each section of the Pall ring fillers for uniformly distributing the absorption liquid.

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