Water replenishing method for drainage heating deaerator of glass production waste heat boiler

Abstract

The invention discloses a water replenishing method for a glass production waste heat boiler drainage heating deaerator, and relates to an energy-saving method for realizing waste heat boiler drainage heat recovery and heating deaerator water replenishing by arranging a heat exchanger to replace a traditional blowdown flash tank. The heat exchanger is provided with heat source medium inlets matched with the glass production lines in number, and steam drum continuous blowdown of the waste heat boiler serves as a shell pass of a heat source medium passing through the heat exchanger; inlet water of the water supplementing mother pipe serves as a cold source medium to flow through the tube pass of the heat exchanger and serves as supplemented water to flow into a deaerator of the glass production line after being heated. The system is simple and effective in design, solves the problem of waste of heat energy and water resources, achieves the purposes of reducing cost and increasing efficiency by recovering heat to improve power generation efficiency and reduce water consumption, and can be popularized and used in a glass kiln waste heat power generation system.

Description

Technical Field

[0001] The invention belongs to the technical field of glass kiln waste heat power generation, and in particular relates to a method for replenishing water for a deaerator for heating waste heat boiler water in glass production. Background Art

[0002] The waste heat boiler of glass kiln is mainly used to recover most of the heat energy in the medium and low temperature waste flue gas discharged by glass kiln. Through the furnace tube heat exchanger, the water is heated to a certain temperature to generate superheated steam, which is finally sent to the steam turbine generator set for continuous output of power generation load. In order to maintain a certain salt content and conductivity of boiler water and prevent excessive salt concentration from affecting steam quality and electrochemical corrosion of the inner wall of the heat exchange tube, the waste heat boiler of glass industry adopts boiler continuous pipe to continuously draw saturated water with high salt content from the steam drum, and discharge it into the "continuous expansion tank" to form steam and enter the deaerator (the deaerator needs 200℃ heating steam. After heating by the deaerator, the dissolved oxygen content in the water is about 9mg / L at normal temperature and pressure. After thermal deoxidation, the dissolved oxygen content in the water can be lower than 15ug / L. The water with reduced oxygen content after the deaerator is returned to the waste heat boiler to supplement water; the other part of the water entering the "continuous expansion tank" forms a drain of nearly 100℃ and is discharged into the ditch. This part of the discharge will cause a lot of heat and water resources. Waste water.

[0003] In the existing technology, the recycling methods for continuous drainage wastewater include introducing the continuous drainage water into the external heating network for use, and the mainstream recycling method is to recover the steam through the continuous drainage expansion tank to the deaerator for heating, and the drainage is directly discharged or recycled into circulating water for use. Figure 1 , the waste hot water from the continuous discharge of the steam drum is discharged into the "continuous expansion tank", and the unqualified water is separated into secondary steam and drain water (waste hot water) by means of pressure reduction and expansion. Since the secondary steam generated by the continuous expansion tank contains a certain amount of heat, about 200°C, it is introduced into the top of the deaerator, and this part of the heat can be used to heat the feed water entering the deaerator. This existing process has the following shortcomings: (1) The separated waste hot water still retains a relatively high temperature but is directly discharged or recycled into the circulating water pool, and there is still a large amount of heat energy loss. (2) Direct discharge of waste water will also cause a waste of water resources. If it is recycled into the circulating water pool, it will affect the cooling effect of the circulating water. (3) It is necessary to control the liquid level of the continuous expansion tank, which increases the difficulty of operation and the workload of operation. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for replenishing water in a deaerator for heating waste heat boiler drainage in glass production, thereby solving the problems in the above-mentioned background technology.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a method for heating deaerator water replenishment by waste heat boiler water for glass production is provided, wherein a heat exchanger is set to recover the heat of waste heat boiler water and use it to heat deaerator replenishment water; the heat exchanger is provided with heat source medium inlets matching the number of glass production lines, and the continuous blowdown of the steam drum of the waste heat boiler is used as the heat source medium to pass through the shell side of the heat exchanger; the inlet water of the water replenishment main pipe is used as the cold source medium to pass through the tube side of the heat exchanger, and after being heated, it flows into the deaerator of the glass production line as replenishment water.

[0006] In a preferred embodiment of the present invention, the continuous blowdown of the steam drum of the waste heat boiler is cooled by a heat exchanger and then recovered to the desulfurization process water tank.

[0007] In a preferred embodiment of the present invention, each heat exchanger is adapted to two glass production lines, and each glass production line is provided with a waste heat boiler.

[0008] In a preferred embodiment of the present invention, a tee is welded between the primary valve and the secondary valve of the continuous blowdown pipeline of the steam drum of the two glass production lines, and the pipelines are respectively led to the heat source medium inlet of the heat exchanger.

[0009] In a preferred embodiment of the present invention, the water supply main pipe is connected to the water inlet pipeline and the return pipeline of the heat exchanger in sequence, the water inlet pipeline and the return pipeline are respectively provided with isolation valves, and the water supply main pipe is provided with a straight-through valve between the connection points of the water inlet pipeline and the return pipeline.

[0010] In a preferred embodiment of the present invention, the heat exchanger is provided with two heat source medium inlets, a heat source medium outlet, a cold source medium inlet and a cold source medium outlet.

[0011] In a preferred embodiment of the present invention, the heat source medium inlet is provided with a pressure measuring point, and the cold source medium inlet and the cold source medium outlet are provided with temperature measuring points.

[0012] In a preferred embodiment of the present invention, the heat exchanger includes a stainless steel heat exchange tube and a shell, and the heat exchange area of ​​the stainless steel heat exchange tube is not less than 20 m2.

[0013] In a preferred embodiment of the present invention, the waste heat boiler is used in a glass kiln waste heat power generation system.

[0014] Compared with the background technology, this technical solution has the following advantages:

[0015] The present invention solves the problem that waste heat cannot be completely recovered in traditional recovery processes (the waste heat discharge of traditional recovery methods is still nearly 100°C, while the present invention can reduce the waste water temperature to below 50°C). In the system of the present invention, the make-up water is heated by heat exchange and then added to the deaerator, which can reduce the amount of steam transported from the steam drum to the deaerator, thereby increasing the steam intake of the steam turbine and increasing the power generation load of the generator; the waste hot water is greatly cooled by heat exchange and then discharged and recovered to the "desulfurization process water tank" for use, reducing the water consumption of the desulfurization process and achieving the technical effect of saving water and electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of heat recovery from existing continuous wastewater.

[0017] Figure 2 This is the process flow chart of waste heat power generation with boilers connected.

[0018] Figure 3 This is a schematic diagram of a system using a blowdown expansion tank;

[0019] Figure 4 is a schematic diagram of a system using a heat exchanger;

[0020] Figure 5 is the structural diagram of the heat exchanger;

[0021] Figure 6 This is one of the cross-sectional views of the heat exchanger;

[0022] Figure 7 This is the second cross-sectional view of the heat exchanger;

[0023] Figure 8 This is a physical picture of the heat exchanger on site.

[0024] Among them, ①7-line heat source medium inlet, ②8-line heat source medium inlet, ③cold source medium inlet, ④cold source medium outlet, ⑤stainless steel heat exchange tube, ⑥heat source medium outlet, ⑦thermometer interface, ⑧pressure gauge interface. DETAILED DESCRIPTION

[0025] In combination with the accompanying drawings and embodiments, a waste heat wastewater heat recovery system is set up by taking our factory's "Zhangbo 7#, 8# glass production line" as an example, and the technical solution of the present invention is described in detail by comparing the sewage expansion tank and the heat exchanger system.

[0026] Each production line in our factory has a corresponding waste heat boiler. The 7# and 8# production lines (because the two boilers are adjacent, if they are set up separately, it will increase the construction cost and increase the workshop space) share a "heat exchanger". After the combined use, the operation of the heat exchanger will not be affected by the water replenishment or sewage discharge interruption of one of the boilers, and one heat exchanger can be saved. It is not considered that three or more float glass production lines share a "heat exchanger" because the continuous pipes and water replenishment pipes introduced into the boiler of the third production line are too long, the pipe resistance is large, the water pump power consumption is increased, and the long-distance temperature drop loss is not economical.

[0027] like Figure 3 Before the implementation of the scheme of the present invention, Zhangbo 7# and 8# glass production lines used blowdown expansion tanks. The 32°C make-up water was directly passed from the make-up water main pipe and then branched into two routes to the 7-line deaerator and 8-line deaerator respectively. The two deaerators were heated by 180°C steam input from the drum to maintain the temperature of the deaerator water tank at 146°C. The 7-line drum and the 8-line drum continuously discharged wastewater at a rate of 0.5t / h each, and the internal saturated water temperature was 180°C, which flowed directly to the "blowdown expansion tank" to exhaust steam to the air and drain water to the ground.

[0028] The amount of water added depends on the design capacity of the boiler. The total amount of water added for the boilers of our factory's 7# glass production line and 8# glass production line is 16t / h. Figure 2 The drum of the waste heat boiler is connected to an economizer, an evaporator and a superheater. The superheater is connected to a steam turbine for supplying energy to a generator. The exhaust steam of the steam turbine is connected to a condenser through a pipeline. The condensate pipeline of the condenser is connected to a deaerator. The deaerator is connected to the economizer through a water supply pipeline. The dissolved oxygen content in water is about 9 mg / L at normal temperature and pressure. After thermal deoxidation by the deaerator, the dissolved oxygen content in water can be lower than 15 ug / L. The water with reduced oxygen content flows to the boiler body water, and then to the "economizer", "steam drum" and each "evaporator" in turn to achieve waste heat reuse, which can be adapted to the glass kiln waste heat power generation system.

[0029] Example

[0030] This embodiment provides a method for heating deaerator water replenishment by waste heat boiler drainage in glass production, by setting a heat exchanger to replace the original blowdown expansion tank, recovering the heat of waste heat boiler drainage and using it to heat deaerator water replenishment. The heat exchanger is provided with a heat source medium inlet matching the number of glass production lines, and the continuous blowdown of the drum of the waste heat boiler is used as the heat source medium to pass through the shell side of the heat exchanger; the water inlet of the water replenishment main pipe is used as the cold source medium to pass through the tube side of the heat exchanger, and after being heated, it flows into the deaerator of the glass production line as replenishment water.

[0031] In this embodiment, the continuous discharge of the steam drum of the waste heat boiler is cooled by the heat exchanger and then recovered to the desulfurization process water tank, which is specifically used for high-pressure atomized water in an environmentally friendly semi-dry desulfurization tower. It has no actual impact, will not affect the desulfurization effect, and will not increase the calcium-sulfur ratio.

[0032] Each heat exchanger is adapted to two glass production lines, and each glass production line is equipped with a waste heat boiler. Tees are welded between the primary valve and the secondary valve of the continuous blowdown pipeline of the steam drum of the two glass production lines, and the pipelines are respectively connected to the heat source medium inlet of the heat exchanger. The water supply main pipe is connected to the water inlet and return pipes of the heat exchanger in turn. The water inlet and return pipes are respectively provided with isolation valves, and the water supply main pipe is provided with a straight-through valve between the connection points of the water inlet and return pipes.

[0033] The heat exchanger is provided with two heat source medium inlets ① and ②, and also provided with a heat source medium outlet ⑥, a cold source medium inlet ③ and a cold source medium outlet ④. The heat source medium inlets ① and ② are provided with pressure measuring points and a pressure gauge interface ⑧; the cold source medium inlet ③ and the cold source medium outlet ④ are provided with temperature measuring points and a thermometer interface ⑦.

[0034] The heat exchanger comprises a stainless steel heat exchange tube ⑤ and a shell, and the heat exchange area of ​​the stainless steel heat exchange tube ⑤ is not less than 20 m2. The stainless steel heat exchange tube ⑤ is made of S304 stainless steel, and the remaining materials are Q345R.

[0035] like Figure 4 As shown, 32℃ make-up water flows from the make-up water main pipe bypassing the straight-through valve to the heat exchanger, the make-up water temperature is increased to 60℃, and then flows back to the make-up water main pipe and branches into two routes to the 7-line deaerator and the 8-line deaerator respectively. The 180℃ heating steam delivered to the deaerator by the two drums is adjusted to reduce by 0.4t / h, and the temperature of the deaerator water tank is maintained at 146℃; the 7# line drum and the 8# line drum continuously discharge wastewater at 0.5t / h each, and the internal saturated water temperature is 180℃. It is redirected to the heat exchanger through a three-way pipeline, cooled to 47.2℃ by heat exchange, and recycled to the "desulfurization process water tank", and the desulfurization system reduces the tap water make-up amount by 1t / h.

[0036] Table 1

[0037]

[0038] Benefit calculation: The steam supply for drum heating is saved by about 0.4t / h. According to the steam consumption rate of the generator set of 5.8kg / kW.h, the excess steam is used for power generation, which can increase the power generation load by 69KW. The wastewater is recycled after the temperature drops, saving 24t of water per day. Annual income = 69*24*365*0.52+24*365*3.2 = 342,300 yuan.

[0039] The investment cost of this case is only 89,000 yuan, which solves the problem of waste of heat energy and water resources, improves power generation efficiency and reduces water consumption by recovering heat to achieve the goal of reducing costs and increasing efficiency. This design and process solution can be promoted and adopted in glass kiln waste heat power generation systems.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for replenishing water in a deaerator for heating waste heat boiler drainage in glass production, characterized in that: A heat exchanger is provided to recover the waste heat boiler drainage heat and use it to heat the deaerator make-up water; the heat exchanger is provided with heat source medium inlets matching the number of glass production lines, and the waste heat boiler drum continuous discharge is used as the heat source medium to pass through the shell side of the heat exchanger; the inlet water of the make-up water main pipe is used as the cold source medium to pass through the tube side of the heat exchanger, and after being heated, it flows into the deaerator of the glass production line as make-up water.

2. A method for replenishing water in a waste heat boiler for heating a deaerator for producing glass according to claim 1, characterized in that: The continuous blowdown from the steam drum of the waste heat boiler is cooled by the heat exchanger and then recovered to the desulfurization process water tank.

3. The method for replenishing water for a deaerator for heating waste heat boiler water for producing glass according to claim 1, characterized in that: Each heat exchanger is adapted to two glass production lines, and each glass production line is equipped with a waste heat boiler.

4. A method for replenishing water in a deaerator for heating waste heat boiler water for producing glass according to claim 3, characterized in that: Tees are welded between the primary valve and the secondary valve of the continuous blowdown pipelines of the drums of the two glass production lines, and the pipelines are respectively led to the heat source medium inlet of the heat exchanger.

5. The method for replenishing water for deaerator of waste heat boiler for glass production according to claim 1, characterized in that: The water supply main pipe is connected to the water inlet pipeline and the return pipeline of the heat exchanger in turn. The water inlet pipeline and the return pipeline are respectively provided with isolation valves. The water supply main pipe is provided with a straight-through valve between the connection points of the water inlet pipeline and the return pipeline.

6. The method for replenishing water for a deaerator for heating waste heat boiler water in glass production according to claim 1, characterized in that: The heat exchanger is provided with two heat source medium inlets, a heat source medium outlet, a cold source medium inlet and a cold source medium outlet.

7. A method for replenishing water in a deaerator for heating waste heat boiler water for producing glass according to claim 6, characterized in that: The heat source medium inlet is provided with a pressure measuring point, and the cold source medium inlet and the cold source medium outlet are provided with temperature measuring points.

8. A method for replenishing water in a deaerator for heating waste heat boiler water for producing glass according to claim 6, characterized in that: The heat exchanger includes a stainless steel heat exchange tube and a shell, and the heat exchange area of ​​the stainless steel heat exchange tube is not less than 20 m2.

9. The method for replenishing water for a deaerator for heating waste heat boiler water in glass production according to claim 1, characterized in that: The waste heat boiler is used in a glass kiln waste heat power generation system.

10. A method for replenishing water in a deaerator for heating waste heat boiler water for producing glass according to claim 9, characterized in that: In the glass kiln waste heat power generation system, the steam drum of the waste heat boiler is connected to an economizer, an evaporator and a superheater; the superheater is connected to a steam turbine for supplying energy to the generator, the exhaust steam of the steam turbine is connected to a condenser through a pipeline, the condensate pipeline of the condenser is connected to a deaerator, and the deaerator is connected to the economizer through a feed water pipeline.

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