Waste heat boiler waste water comprehensive utilization system

Abstract

The utility model discloses a waste heat boiler waste water comprehensive utilization system which comprises a waste water collecting tank, a reaction tank, a sedimentation tank, a buffer tank, ultrafiltration membrane equipment and a deaerator which are communicated in sequence, a heat preservation jacket is arranged outside the waste water collecting tank in a sleeved mode, a spiral heat exchange water pipe is arranged in the heat preservation jacket, and the heat exchange water pipe is tightly attached to the outer wall of the waste water collecting tank; a sludge outlet of the sedimentation tank is connected with a sludge thickening tank through a first slurry pump, the sludge thickening tank is communicated with a plate-and-frame filter press through a second slurry pump, and a water outlet of the plate-and-frame filter press and a water outlet of the sludge thickening tank are both communicated with the sedimentation tank. On one hand, the boiler waste water is subjected to waste heat recovery, the temperature of softened water entering the boiler is increased, and fuel consumption is reduced; and on the other hand, the boiler wastewater is deeply treated, so that secondary utilization of the wastewater is realized, wastewater discharge and environmental pollution are reduced, purified water is saved, waste of water resources is reduced, and dual effects of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater utilization, in particular to a comprehensive utilization system for waste heat boiler wastewater. Background Art

[0002] During the daily operation of the waste heat boiler, in order to ensure the quality of the boiler water, continuous blowdown and regular blowdown are required. Continuous blowdown is also called surface blowdown. This blowdown method continuously discharges the boiler water with the highest concentration from the surface layer of the water in the steam drum. Its function is to reduce the salt content and alkalinity in the boiler water and prevent the boiler water concentration from being too high and affecting the steam quality. Regular blowdown is also called intermittent blowdown or bottom blowdown, and its function is to remove the water slag accumulated at the lower part of the boiler and the soft precipitate formed after phosphate treatment. The rated evaporation capacity of the waste heat boiler in our factory is 25t / h, the continuous blowdown rate is 2% of the rated evaporation capacity, and the regular blowdown rate is 1% of the rated evaporation capacity. Through the daily operation evaporation capacity of the waste heat boiler, it can be calculated that the blowdown volume of a waste heat boiler in one day is 18t. There are currently two waste heat boilers of the same model in operation in our factory, and the blowdown volume in one day is about 36t. The discharged water is all collected in the cooling well. In the early stage of project construction, the recovery and reuse of the fixed drainage volume of the waste heat boiler were not considered, and no corresponding equipment for recovering the fixed drainage was designed to recover the fixed drainage generated by the waste heat boiler, resulting in waste of water resources, increasing the operating cost of the enterprise, and also causing a burden on the environment. With the enhancement of environmental awareness and the increasing tension of resources, how to effectively recover and utilize the fixed drainage of the boiler has become an important technical challenge. Therefore, it is urgent to develop an efficient and reliable system for recovering and reusing the fixed drainage of the boiler. Summary of the Invention

[0003] The purpose of the utility model is to provide a comprehensive utilization system for waste heat boiler wastewater to solve the problems in the above background art.

[0004] To achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A comprehensive utilization system for waste heat boiler wastewater includes a wastewater collection tank, a reaction tank, a sedimentation tank, a buffer tank, an ultrafiltration membrane device, and a deaerator connected in sequence. The outside of the wastewater collection tank is sleeved with a heat preservation jacket, and a spiral heat exchange water pipe is arranged in the heat preservation jacket and is closely attached to the outer wall of the wastewater collection tank; the sludge outlet of the sedimentation tank is connected to a sludge thickening tank through a first slurry pump, the sludge thickening tank is connected to a plate and frame filter press through a second slurry pump, and the water outlet of the plate and frame filter press and the water outlet of the sludge thickening tank are both connected to the sedimentation tank.

[0006] Compared with the prior art, the utility model has the following beneficial effects:

[0007] On the one hand, the waste water comprehensive utilization system of the utility model recovers the waste heat of the boiler waste water, improves the temperature of the softened water entering the boiler, and reduces the fuel consumption; on the other hand, through the deep treatment of the boiler waste water, not only the secondary utilization of the waste water is realized, the waste water discharge and environmental pollution are reduced, but also the purified water is saved, the waste of water resources is reduced, and the dual effects of energy conservation and emission reduction are achieved. Brief Description of the Drawings

[0008] Figure 1 It is a structural schematic diagram of the utility model.

[0009] In the figure, #1 - waste water collecting tank, #101 - heat preservation jacket, #102 - heat exchange water pipe, #2 - reaction tank, #3 - sedimentation tank, #4 - buffer tank, #5 - ultrafiltration membrane equipment, #6 - deaerator, #7 - first slurry pump, #8 - sludge thickening tank, #9 - plate and frame filter press, #10 - second slurry pump, #11 - first water supply pump, #12 - agitator, #13 - second water supply pump, #14 - reflux pump. Detailed Embodiment

[0010] The following further explains and illustrates the utility model in conjunction with the drawings and specific embodiments.

[0011] As Figure 1 shown, a waste heat boiler waste water comprehensive utilization system includes a waste water collecting tank #1, a reaction tank #2, a sedimentation tank #3, a buffer tank #4, an ultrafiltration membrane equipment #5 and a deaerator #6 connected in sequence. A heat preservation jacket #101 is sleeved outside the waste water collecting tank #1, and a spiral heat exchange water pipe #102 is arranged in the heat preservation jacket #101, and the heat exchange water pipe #@02 is closely attached to the outer wall of the waste water collecting tank #1; a first water supply pump #11 is connected between the waste water collecting tank #1 and the reaction tank #2. One of the sludge outlets of the sedimentation tank #3 is connected to the reaction tank #2 through a reflux pump #14, and on the other hand, it is connected to the sludge thickening tank #8 through a first slurry pump #7. The sludge thickening tank #8 is connected to the plate and frame filter press #9 through a second slurry pump #10. The water outlet of the plate and frame filter press #9 and the water outlet of the sludge thickening tank #8 are both connected to the sedimentation tank #3; an overflow port is arranged at the top of the sedimentation tank #3, and the supernatant overflows into the buffer tank #4 through the overflow port for temporary storage. At the same time, to ensure that the water entering the ultrafiltration membrane equipment #5 from the buffer tank #4 has sufficient pressure, a second water supply pump #13 is also connected between the buffer tank #4 and the ultrafiltration membrane equipment #5.

[0012] The specific working process of the utility model is as follows:

[0013] The boiler wastewater first enters the wastewater collecting tank 1 for centralized storage. While storing water, the valve of the softened water pipe connected to the hot water exchange pipe 102 is opened to fill the hot water exchange pipe 102 with the softened water to be fed into the boiler. The waste heat of the wastewater in the wastewater collecting tank 1 is used to increase the temperature of the softened water entering the boiler, so as to reduce the fuel consumption of the boiler. When the temperature of the wastewater in the wastewater collecting tank 1 drops below 40°C, the heat exchange is completed, and the first water feed pump 10 is started to pressurize the wastewater from the wastewater collecting tank 1 and send it into the softening treatment device. The softening treatment device consists of three parts: a reaction tank 2, a sedimentation tank 3 and a buffer tank 4.

[0014] The softening process is as follows: the boiler wastewater first enters the reaction tank 2, alkali and soda ash are added to the reaction tank 2, and the pH value of the wastewater in the tank is adjusted to 11-12. At this time, the Ca in the wastewater 2+ Mg 2+ The reaction produces CaCO3, Mg(OH)2, and MgCO3 flocculent precipitates, and then the wastewater flows from the reaction tank 2 into the sedimentation tank 3 for separation and precipitation. Most of the substances such as CaCO3, Mg(OH)2, and MgCO3 are precipitated and removed, and the supernatant flows into the buffer tank 4 from the overflow hole at the top of the sedimentation tank 3. The wastewater in the buffer tank 4 then enters the ultrafiltration membrane equipment 5 through the second water supply pump 13 for filtration and then discharges the water. After deoxygenation by the deaerator 6 (to prevent oxygen corrosion of the waste heat boiler tube wall), the water is pumped into the boiler together with the preheated softened water in the heat exchange water pipe 102 for secondary utilization.

[0015] Part of the precipitated sludge produced in the sedimentation tank 3 is returned to the reaction tank 2 through the reflux pump 14 for secondary reaction, so that the excess reagents in the precipitate can fully react and reduce the consumption of reagents; the rest of the sludge enters the sludge thickening tank 8 through the first mud pump 7 for concentration treatment, and the concentrated sludge is pumped into the plate and frame filter press 9 through the second mud pump 10 for further dehydration. The dehydrated sludge is transported out for treatment.

[0016] The supernatant in the sludge thickening tank 8 flows out from the upper effluent weir and is returned to the sedimentation tank 3 together with the filtrate produced by the plate and frame filter press 9 for further treatment.

[0017] During the above working process, a temperature sensor is also installed on the top of the water collection tank 1 to monitor the temperature of the waste liquid in the tank; a stirrer 12 is also installed on the reaction tank 2, which can stir and mix the reaction between the wastewater and the reagent to improve the reaction efficiency; the sedimentation tank 3 adopts an inclined tube sedimentation tank with high removal efficiency, short processing time and small footprint; the ultrafiltration membrane equipment 5 adopts a tubular alkali-resistant ultrafiltration membrane and adopts cross-flow filtration for filtration. The cross-flow filtration method makes the filter surface flow rate high, not easy to scale and clog, and has strong anti-pollution ability, and has high compatibility with the water quality requirements of the precipitated water.

[0018] In summary, the waste water comprehensive utilization system of the utility model can not only recover the waste heat in the waste water, but also realize the secondary utilization of the waste water, reduce the waste water discharge, save the purified water, reduce the waste of water resources and fuel consumption, and has the dual effects of energy conservation and emission reduction.

Claims

1. An integrated utilization system for waste heat boiler wastewater, characterized in that, It includes a wastewater collection tank (1), a reaction tank (2), a sedimentation tank (3), a buffer tank (4), an ultrafiltration membrane device (5) and a deaerator (6) which are connected in sequence. A heat preservation jacket (101) is sleeved outside the wastewater collection tank (1), and a spiral heat exchange water pipe (102) is arranged inside the heat preservation jacket (101), and the heat exchange water pipe (102) is closely attached to the outer wall of the wastewater collection tank (1); the sludge outlet of the sedimentation tank (3) is connected to a sludge thickening tank (8) through a first slurry pump (7), the sludge thickening tank (8) is communicated with a plate and frame filter press (9) through a second slurry pump (10), and the water outlets of the plate and frame filter press (9) and the sludge thickening tank (8) are both communicated with the sedimentation tank (3).

2. The comprehensive utilization system for waste heat boiler wastewater according to claim 1, wherein A first water supply pump (11) is connected between the wastewater collection tank (1) and the reaction tank (2).

3. The comprehensive utilization system for waste heat boiler wastewater according to claim 1, wherein, A reflux pump (14) is also connected between the sludge outlet of the sedimentation tank (3) and the reaction tank (2).

4. The comprehensive utilization system for waste heat boiler wastewater according to claim 1, characterized in that, A stirrer (12) is also installed on the reaction tank (2).

5. The comprehensive utilization system for waste heat boiler wastewater according to claim 1, wherein A second water supply pump (13) is connected between the buffer tank (4) and the ultrafiltration membrane device (5).

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