WO2013131364A1

WO2013131364A1 - Treatment system for tail gas generated during acid-water conversion in cold rolling acid-washing acid regeneration process

Info

Publication number: WO2013131364A1
Application number: PCT/CN2012/081854
Authority: WO
Inventors: 崔海东; 刘江伟; 刘道献; 李大量; 伍永锐; 初国君; 李飞; 曲长伟; 张甲远; 石振伟; 李占江
Original assignee: 唐山建龙实业有限公司
Priority date: 2012-03-09
Filing date: 2012-09-24
Publication date: 2013-09-12
Also published as: CN102586793A; CN102586793B

Abstract

Provided is a treatment system for tail gas generated during acid-water conversion in cold rolling acid-washing acid regeneration process, which belongs to the technical field of acid regeneration device of cold rolling acid-washing in metallurgy industry. The technical solution comprises: a bypass pipeline is additionally arranged by the side of an acid charge regulating valve (10) of a pre-concentration device, on which a regulating valve (11) is provided. Without being controlled by an acid operation mode or a water operation mode, the regulating valve can be randomly opened or closed, and the regulating valve is opened when the system carries out the conversion in advance and is closed in the normal acid operation mode or rinsing water operation mode. The treatment system carries out acid and water conversion in advance，and directly converts a new water operation into an acid operation, thus it solves the atmosphere pollution problem caused by the iron ions-containing tail gas generated during acid-water conversion during acid regeneration process. During conversion, the waste acid returns to a waste acid pot so as to be saved, thus the acid pollution is avoided; and in addition, because of the acid regeneration process, discharging of the acid-including waste water into the water treatment is reduced, thus water treatment cost is reduced.

Description

Treatment system for converting tail acid from acid and water in cold rolling pickling acid regeneration process

The invention relates to a treatment system for converting tail acid from acid and water in a cold rolling pickling acid regeneration process, and belongs to the technical field of cold rolling pickling acid regeneration equipment in the metallurgical industry.

Background technique

At present, the waste acid produced by the pickling unit in the metallurgical industry is all in the acid regeneration process. The acid regeneration device works independently of the pickling unit. The principle is that the acid washed waste acid is calcined, dedusted, cooled, absorbed, and then the free acid is returned to the pickling unit, and the iron oxide powder is obtained. The process flow is shown in FIG. The process is divided into four modes of operation: 1. New water operation mode: After the pressurized water is pressurized, it is controlled by the valve, directly enters the spray gun, and the roaster is completely cleaned. 2. Rinsing water operation mode: The rinsing water enters the system through the liquid level control of the preconcentrator through a pneumatic valve. The rinsing water enters the circulating pump of the preconcentrator from the water collecting tank of the preconcentrator, and a part of the rinsing water flow enters The feed pump pipe of the roaster is supplied to the spray gun of the roaster, and enters the roasting furnace to clean or cool the roaster. 3. Acid operation mode: The amount of waste acid corresponding to the temperature control loop enters the system through the liquid level controller of the preconcentrator, and the concentrated waste acid is transferred from the water collection tank of the preconcentrator to the circulating pump of the preconcentrator, wherein A part of the concentrated waste acid is separated, and the feeding pump of the charging furnace is supplied to the blasting gun of the roaster; the washing water and the rinsing water of the washing tower are used as the absorbing water of the absorption tower, and the hydrogen chloride is absorbed to obtain the regenerated acid having a concentration of 18%, and is flowed to the regenerative acid tank. . 4. Water operation acid transfer operation or acid operation water transfer operation mode: During the water operation of the unit, when the acid operation condition is available, press the acid operation switch button, the unit automatically switches to the acid operation mode, and the liquid level of the preconcentrator is The set value is automatically decreased. At this time, the roaster is still in the water operation. When the liquid level of the preconcentrator drops to the set value, the preconcentrator inlet acid valve is automatically set at the operating position to realize the operation from water operation to acid operation. Switching; The procedure for the acid operation to the water operation mode is reversed. BACKGROUND OF THE INVENTION The problem is: when the liquid level of the preconcentrator drops to a set value (the program is automatically given no operation), the acid inlet valve of the preconcentrator is automatically set at the operating position, and the acid solution is added to the preconcentrator; Although the system is switched to the acid operation at this time, the liquid sprayed in the baking furnace is still water, or a mixed liquid of acid and water; the amount of waste acid added to the preconcentrator is constant because the amount of liquid supplied to the roasting is constant It is also constant. In the initial stage of acid operation, the liquid in the preconcentrator is a mixture of less acid and more water. HCL and iron ions are contained in the combustion hot gas of the roaster, and the HCL content in the preconcentration circulating liquid is low, and the iron ions in the combustion hot gas cannot be absorbed. , or iron ions are not soluble in the acid and water mixture, although the combustion hot gas containing iron ions is blocked by the absorption tower and the packing of the washing tower, but the iron ions that cannot be completely absorbed are discharged into the atmosphere with the exhaust gas through the bacon. Due to the high concentration of iron ions, the exhaust gas emitted is red, which seriously pollutes the environment. The system acid operation continues, the liquid in the preconcentrator is gradually replaced by water into acid, and the iron ions in the tail gas are gradually reduced until a certain amount of time is required until the preconcentrator is fed to the preconcentrator. During the time when the liquid is completely replaced by acid, the color of the exhaust gas is viewed from the outside, which is a process of gradually changing from red to white. The red exhaust gas containing a large amount of iron ions discharged in this process seriously pollutes the environment and is in urgent need of treatment.

Summary of the invention

The object of the present invention is to provide a treatment system for converting tail gas between acid and water in a cold rolling pickling acid regeneration process, so that the discharged tail gas contains almost no iron ions, does not emit red smoke, reduces environmental pollution, and reduces production cost. The above problems in the background art are solved.

The technical solution of the present invention is:

A treatment system for converting tail acid from acid and water in a cold rolling pickling acid regeneration process, comprising a baking furnace, a preconcentrator, an absorption tower, a fan, a washing tower, a waste acid tank, a regenerative acid tank and a rinsing water tank, and is acid The washed waste acid is calcined, dedusted, cooled, absorbed, and then free acid is produced, and iron oxide powder is obtained at the same time; the cold rolling pickling acid regeneration process is divided into four operation modes: new water operation mode, rinsing water operation mode, acid operation Mode, water operation acid transfer operation or acid operation water transfer operation mode; there is a rinse water regulating valve between the preconcentrator and the rinse water tank, the valve can be opened under the control of the system water operation mode; the preconcentrator and the waste An acid regulating valve is arranged between the acid tanks, and the valve can be opened under the control of the acid operation mode of the system; the special feature is that a bypass pipe is installed beside the acid regulating valve of the preconcentrator, the bypass pipe The regulating valve is arranged on the upper; the regulating valve is not controlled by the acid operation mode and the water operation mode, and can be opened or closed at any time, and the regulating valve is opened when the system is replaced in advance, the normal sour operation Turns off when in mode or rinse water mode. If the pre-concentrator's acid inlet valve is abnormal, use this regulator to replenish the preconcentrator. Install the hand valve on the front of the regulating valve to avoid the phenomenon that the regulating valve is not tightly closed or leaking, and add a fuse to the regulating valve.

The top of the roasting furnace is provided with a concentrated acid filter and a spray gun, and a manual sewage discharge valve is installed at the end of the spray pipe, and the sewage valve and the spray gun pipe are connected with the sewage pipe of the top of the roasting furnace. A drain valve is installed behind the connection point between the sewage valve and the sewage pipe at the top of the roasting furnace. Between the installed drain valve and the drain valve, a new pipe with a valve is installed, and the outlet of the new pipe is connected to the inlet of the waste acid tank. Behind the valve of the new pipe, a backwashing water pipe is provided, and a backflushing valve is arranged on the backflushing pipe.

The sewage valve, the sewage valve and the pipeline provided by the invention are connected with the sewage pipeline at the top of the roasting furnace. When an abnormality occurs, the acid liquid in the nozzle pipe of the roasting furnace can be discharged to avoid crystallization of the spray gun pipeline.

The new piping and valves provided by the present invention are connected to the waste acid tank inlet to return the spent acid at the time of replacement to the spent acid tank. The backwash water pipe on the new pipe is set to clean the concentrated waste acid in the new pipe in time after the replacement, to prevent crystallization of the new pipe.

The invention has the beneficial effects that: acid and water replacement are carried out in advance, and the operation is directly converted into acid by the operation of fresh water; and the problem that the tail gas contains iron ions in the acid regeneration and the atmospheric pollution is caused by the acid regeneration is solved. The waste acid at the time of replacement returns to the waste acid tank to save waste acid and avoid acid pollution. Acid regeneration reduces the acid-containing wastewater discharged to the water treatment, reducing the cost of water treatment; installing new pipelines and backwash water pipelines , timely flushing to prevent crystallization of new pipes.

DRAWINGS

1 is a schematic view of a background process flow;

Figure 2 is a schematic view of an embodiment of the present invention;

Figure 3 is a schematic view showing the top of a baking furnace according to an embodiment of the present invention;

In the figure: roaster 1, preconcentrator 2, absorption tower 3, fan 4, washing tower 5, waste acid tank 6, regenerative acid tank 7, rinsing water tank 8, inlet and rinse water regulating valve 9A. Acid regulating valve 10B regulating valve 11C sewage valve 12, spray gun 13, spray pipe 14, sewage pipe 15, sewage valve 16, pit 17, new pipe 18, valve 19, backwash water pipe 20, backwash water pipe valve 21 , chimney 22.

detailed description The present invention will be further described by way of embodiments with reference to the accompanying drawings.

In an embodiment, a treatment system for converting tail acid between acid and water in a cold rolling pickling acid regeneration process, comprising a roaster 1, a preconcentrator 2, an absorption tower 3, a fan 4, a washing tower 5, and a waste acid tank 6 , the regenerative acid tank 7 and the rinsing water tank 8, the acid washed waste acid is calcined, dusted, cooled, absorbed, and then the free acid is obtained, and the iron oxide powder is obtained at the same time; the cold rolling pickling acid regeneration process is divided into four operation modes. : a new water operation mode, a rinsing water operation mode, an acid operation mode, a water operation acid conversion operation or an acid operation water conversion operation mode; an inlet rinsing water regulating valve 9 is provided between the preconcentrator 2 and the rinsing water tank 8, the valve It can be opened under the control of the system water operation mode; the acid adjustment valve 10 is provided between the preconcentrator 2 and the waste acid tank 6, and the valve can be opened under the control of the system acid operation mode; A bypass pipe is arranged beside the acid regulating valve 10 of the concentrator, and the regulating valve 11 is arranged on the bypass pipe; the regulating valve is controlled by the acid operation mode and the water operation mode, and can be turned on or off at any time. Regulating valve is opened when the system is replaced in advance, off normal operation mode or the rinsing water an acid mode of operation.

If the acid inlet valve of the preconcentrator is abnormal, use this regulator valve 11 to supply acid to the preconcentrator. Install the hand valve on the front of the regulating valve to avoid the phenomenon that the regulating valve is not tightly closed or leaking, and add a fuse to the regulating valve.

A roasting furnace top is provided with a concentrated acid filter and a spray gun 13. A manual drain valve 12 is installed at the end of the spray gun pipe 14, and the drain valve and the spray gun pipe are connected to the sewage pipe 15 at the top of the roasting furnace. A sewage valve 16 is installed behind the connection point of the sewage pipe and the sewage pipe at the top of the roasting furnace; between the installed sewage valve and the sewage valve, a new pipe 18 with a valve 19 is provided, and the outlet of the new pipe is The inlet of the waste acid tank 6 is connected; behind the valve of the new pipe, a backwash water pipe 20 is provided, and the back flushing pipe 21 is provided on the back flush pipe.

The specific four modes of operation of the present invention are switched: the rinsing water operation mode is first executed, and the new water operation mode is switched when the various operating parameters of the system reach the acid operation mode condition; the preconcentrator 2 is manually closed by the rinsing water regulating valve 9; The feeding pump of the roaster 1 is in normal operation, controlling the operating parameters in the acid operation mode, the pressure gauge and the flow meter installed on the feeding pump pipe, the displayed parameters are in the controllable range, the sewage valve 12 is opened, and the sewage valve 16 is closed. , open the valve 19 on the new pipe 18; when the liquid level of the pre-concentrator drops to the acid and water conversion value, the regulating valve 11 opened into the pre-concentrator supplies acid to the pre-concentrator to ensure the pre-preservation The operation of the concentrator is stable, and the opening range of the regulating valve 11 is adjusted; the system performs a new water operation mode, and the rinsing water in the preconcentrator 2 is replaced with acid in advance, and the liquid in the preconcentrator is completely replaced by water as the replacement time is extended. The acid, pre-concentrator circulation pump outlet pressure gradually increases from the pressure in the water operation mode, and the pressure replacement to the acid operation mode ends; the liquid level of the control preconcentrator is slightly higher than that in the normal acid operation mode. The preconcentrator regulating valve 11 is closed, the drain valve 12 is closed, the drain valve 16 is opened, and the valve 19 on the new line 18 is closed; the system switches to the acid operating mode after switching to the rinsing water operation mode, and the acid operation mode is continued.

Precautions for replacement: 1. Pre-concentrator into the rinsing water regulating valve 9 When the replacement is not tight or there is an internal leakage, the hand valve in front of the rinsing water regulating valve 9 must be closed. 2. Switch to the rinse water operation mode and then quickly switch to the acid operation mode. Do not switch to the rinse water operation mode and then perform the rinse water operation mode. This purpose is to prevent the liquid in the preconcentrator from being converted from acid to water. 3. During the replacement process, the parameters of the system should be guaranteed in the acid operating mode. 4. Regulating valve 11 There must be no internal leakage or tight closing. 5. Observe the effect of displacement, and extend the acid reflux time by 30 minutes, or observe the pressure when the outlet pressure of the pre-concentrator circulation pump reaches the acid operation mode. 6. Adjust the opening range of the drain valve according to the actual flow rate of the feed pump, and basically control the flow rate in the normal acid operation mode. 7. When the system replacement is switched to the acid operation mode, the drain valve and the valve on the new pipe must be closed to open the drain valve. The blowdown valve is open during normal production and the valve on the new pipe is closed. 8. When the system replacement is over to the acid operation mode, pay close attention to the crusher and rotary valve at the bottom of the roasting furnace to avoid blockage of the crusher and rotary valve.

Claims

WO 2013/131364 Claim PCT/CN2012/081854

1. A treatment system for converting tail acid from acid and water in a cold rolling pickling acid regeneration process, comprising a baking furnace (1), a preconcentrator (2), an absorption tower (3), a fan (4), a washing tower ( 5), waste acid tank (6), regenerative acid tank (7) and rinsing water tank (8), the acid washed waste acid is calcined, dusted, cooled, absorbed, and then free acid is produced, and iron oxide powder is obtained at the same time; The cold-rolled pickling acid regeneration process is divided into four operating modes: new water operation mode, rinse water operation mode, acid operation mode, water operation acid transfer operation or acid operation water transfer operation mode; preconcentrator (2) and rinse water There is a flushing water regulating valve (9) between the tank (8), which can be opened under the control of the system water operation mode; the acid adjustment between the preconcentrator (2) and the waste acid tank (6) Valve (10), which can be opened under the control of the system acid operation mode; characterized in that: a bypass pipe is arranged beside the acid inlet regulating valve (10) of the preconcentrator, and a regulating valve is arranged on the bypass pipe (11); regulating valve is not operated by acid Type and mode of operation to control the water, can be opened or closed at any time, the regulating valve is opened when the system is replaced in advance, the acid mode of operation turn off the normal mode of operation or the rinsing water.

2. A treatment system for converting tail gas from acid to water in a cold rolling pickling acid regeneration process according to claim 1, wherein the top of the baking furnace is provided with a concentrated acid filter and a spray gun (13) in the spray gun pipe (14). A manual drain valve (12) is installed at the end, and the drain valve and the gun pipe are connected to the sewage pipe (15) at the top of the roasting furnace. A drain valve (16) is installed behind the connection point between the sewage valve and the sewage pipe at the top of the roasting furnace. A new pipe (18) with a valve (19) is installed between the installed sewage valve and the sewage valve. The outlet of the new pipe is connected to the inlet of the waste acid tank (6); behind the valve of the new pipe, a backwash water pipe (20) is arranged, and a back flush valve (21) is arranged on the backflush pipe.

3. The treatment system for converting tail acid from acid and water in the cold rolling pickling acid regeneration process according to claim 1 or 2, characterized in that the four operation modes are switched: the rinsing water operation mode is first executed, and the operation of the system is performed. Switch to the new water operation mode when the parameter reaches the acid operation mode condition; manually turn off the preconcentrator (2) into the rinse water regulating valve (9); the feed pump of the baking furnace (1) is operating normally, and is controlled in the acid operation mode. Operating parameters, open the drain valve (12), close the drain valve (16), open the valve (19) on the new pipe (18); when the liquid level of the pre-concentrator drops to the acid and water conversion value, open the pre-concentration The regulator valve (11) supplies acid to the preconcentrator to ensure stable operation of the preconcentrator and adjust the opening range of the regulating valve (11). The system performs a new water operation mode and replaces the preconcentrator (2) with acid in advance. Rinsing water, As the replacement time is extended, the liquid in the preconcentrator is completely replaced by water, the pressure of the circulating pump outlet of the preconcentrator is gradually increased by the pressure in the water operation mode, and the pressure replacement in the acid operation mode is ended; the preconcentrator is controlled; The liquid level is slightly higher than the liquid level in the normal acid operation mode, and the preconcentrator control valve is closed.

(11), close the drain valve (12), open the drain valve (16), close the valve (19) on the new pipe (18); quickly switch to the acid operation mode after the system switches to the rinse water operation mode, continue the acid operation mode.

4. A treatment system for converting tail gas from acid to water in a cold rolling pickling acid regeneration process according to claim 1 or 2, characterized in that a bypass pipe is installed beside the acid regulating valve (10) of the preconcentrator. The bypass pipe is provided with a regulating valve (11) and a hand valve; a waste acid recovery pipe (18) and a valve (19) for roasting the top of the furnace; a backwash water pipe (20) and a valve (21).