Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B27/00—Rolls, roll alloys or roll fabrication; Lubricating, cooling or heating rolls while in use
  • B21B27/06—Lubricating, cooling or heating rolls
  • B21B27/10—Lubricating, cooling or heating rolls externally
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone

Definitions

• the present invention relates to a roll cooling method for a cold rolling mill, and particularly to a method for maintaining the friction between a rolling roll surface and a rolled material surface during rolling in a cold rolling at an appropriate value and reducing the pressure.
• the present invention relates to a process for preventing slime formation of roll cooling water for cooling a roll and a material to be rolled to a predetermined temperature or lower.
• the friction between the surface of the rolling roll and the surface of the material to be rolled during rolling is maintained at an appropriate value, and the rolling roll and the material to be rolled are cooled to a predetermined temperature or less. There is a need to.
• a recirculation method there are two types of cooling methods for this purpose, a recirculation method and a direct method.
• rolling oil is added to cooling water to form an emulsion liquid, which is circulated and supplied in large quantities to the rolling roll and the material to be rolled to simultaneously perform lubrication and cooling.
• a direct method as shown in Fig. 1, rolling oil is applied to the metal strip (1), which is the material to be rolled, and the rolling oil header (2) Injecting oil to cool the work roll (3) and the metal strip Water is injected into the work outlet (3) by nozzles in the roll cooling water header ( 4 ) to cool it.
• the cooling water and rolling oil after injection are collected in a drainage tank ( 5 ), and after removing impurities such as oil and iron powder by a water purification device (6), the cooling tower (cooler) (7) ), Is supplied with fresh water from the fresh water supply pipe (8), and is supplied to the cooling water header ( 4 ) via the pipe 0 by the pump ( 9 ) and used for circulation.
• the oil separated by the water purification device (6) is regenerated in the regenerator ⁇ , temporarily stored in the rolling oil tank, where new oil is replenished as necessary, Is supplied to the rolling oil header (2) through the rolling oil supply pipe (2) and is used for circulation.
• the method (i) has a problem that the water consumption is large, and the method ( 2 ) has an adverse effect on the surface quality of the metal strip by increasing the chlorine concentration in the cooling water during circulation.
• problems such as high drug costs.
• the present invention has the effect that ozone has a higher bactericidal effect than conventionally used chlorine and has no effect on metal strip since it is decomposed into oxygen in a relatively short time and does not accumulate and remain. Injecting ozone into the roll cooling water based on the recognition of.
• the present invention by setting the ozone concentration of the cooling water to 0.1 ⁇ m or more, the generation of slime in the cooling water supply pipe is prevented, and the quality of the metal strip is improved.
• the required ozone concentration can be maintained by setting the cycle of injecting ozone into the cooling water within 48 hours, and the time required for injecting ozone into the cooling water supply pipe can be reduced. Adherent organisms can be completely removed and suppressed.
• the present invention by setting the duration of injecting ozone into the cooling water to 1 minute or more, it is possible to completely remove and suppress the creatures attached to the slim on the inner wall of the cooling water supply pipe. .
• a plurality of locations are provided in the middle of the water supply pipe, for example, at two places at the outlet side of the cooling tower and at an intermediate position of the water supply pipe. Injecting the required amount of cooling water into the cooling water to maintain the required ozone concentration in the cooling water by making the injected ozone concentration and amount much lower than when only one is injected at the outlet of the cooling tower. Can be done.
• the ozone half-life can be extended, and the amount of injected ozone can be reduced.
• the ozone concentration in the cooling water is stabilized by controlling the flow rate of the cooling water in the water supply pipe to stabilize the residence time of ozone, and thereby the roll cooling at the end of the water supply pipe is performed.
• a predetermined ozone concentration value can be maintained in the water header.
• Fig. 1 is a system diagram of a rolling oil and a roll cooling water by a direct method of a conventional cold rolling mill
• Fig. 2 shows a roll cooling method of a cold rolling mill according to an embodiment of the present invention
• Fig. 3 is a block diagram of a water treatment system to be described
• Fig. 3 is a block diagram of an ozone generation supply device
• Fig. 4 is a block diagram of a water treatment system to explain another embodiment of the present invention.
• Fig. 5 is a graph showing the relationship between the number of installed ozone generating and supplying devices and the required amount of ozone injection
• Fig. 6 is a graph showing the relationship between dwelling time and ozone concentration after ozone injection.
• FIG. 1 is a system diagram of a rolling oil and a roll cooling water by a direct method of a conventional cold rolling mill
• Fig. 2 shows a roll cooling method of a cold rolling mill according to an embodiment of the present invention.
• Fig. 3 is
• FIG. 7 is a system block diagram of a water treatment system for explaining still another embodiment of the present invention
• FIG. 8 is a diagram of cooling water in which cooling water PH concentration is used as a parameter.
• Graph showing changes over time in ozone concentration Fig. 9 shows the relationship between the PH concentration of cooling water and the half-life of ozone in cooling water
• Fig. 10 shows the required target ozone concentration at the end of the water supply pipe.
• FIG. 11 is a graph showing the relationship between the amount of ozone injected and the PH concentration of the cooling water required to secure the temperature
• FIG. 11 is a system block diagram of a water treatment system illustrating still another embodiment of the present invention
• FIG. This is a graph showing the relationship between the flow rate of cooling water in the water supply pipe and the ozone concentration.
• FIG. 2 shows an example in which the present invention is applied to a cooling system of a direct-type cold rolling mill.
• the cooling water in the cooling water supply pipe 0 is provided at the outlet of the water supply pump (9).
• Ozone is injected from the ozone generation and supply device ⁇ by the ejector ⁇ .
• the ejector ⁇ is provided at the outlet side of the water supply pump (9) in the ozone injection pipe ⁇ w connected in parallel with the cooling water supply pipe 0, and the cooling water is supplied from the supply pipe (from the high pressure) by the ejector pump 8). Ejector ⁇ .
• the ozone generation and supply device ⁇ raises the pressure of the oxygen supplied from the oxygen supply device 9 ) by the circulation blower ⁇ )) and sends it to the ozone generator ⁇ , and a part of the supplied oxygen is converted to ozone. Converted to produce ozone containing gas.
• the ozone generator for example, an AC or high voltage is applied between electrodes between dielectrics such as a glass plate to generate a silent discharge, and oxygen is caused to flow between the dielectrics and the electrodes. Generates ozone-containing gas.
• Oxygen supplied from the oxygen supply device ⁇ should have a purity of 99.9% or more and an atmospheric pressure equivalent dew point of -50 ⁇ or less.
• the ozone concentration in the ozone-containing gas generated by the ozone generator ⁇ is around 4%, and the remaining 96% by weight is oxygen, which is low. Therefore, if the ozone-containing gas generated by the ozone generator ⁇ is used as it is, the consumption of oxygen will increase, so the ozone adsorption tower ⁇ , which temporarily stores ozone, is connected to the ozone generator ⁇ via the valve ⁇ . Provided.
• the ozone adsorption tower ⁇ has an adsorbent that preferentially adsorbs ozone in the ozone-containing gas sent from the ozone generator ⁇ , and an ozone adsorber to increase the ozone adsorption capacity for a certain volume of this adsorbent.
• the cooling fin ⁇ through which cold gas from the refrigerator ⁇ is passed to cool the ozone adsorption tower ⁇ at the time, and the temperature raising fin to facilitate desorption of ozone saturated and adsorbed on the adsorbent ⁇ And are provided.
• a heating medium is sent from a brine tank through a pipe ⁇ by a pump ⁇ and circulated, and the heating tank is heated in a A heater (not shown) is provided to control the temperature-raising medium so as to always keep it at a predetermined temperature.
• oxygen is boosted from the oxygen supply device 9 ) shown in Fig. 3 by the circulation blower ⁇ and sent to the ozone generator ⁇ to generate this ozone.
• a part of the supplied oxygen is converted to ozone in the reactor, and the generated ozone-containing gas is sent to the ozone adsorption tower ⁇ via the control valve ⁇ .
• the adsorbent in the ozone adsorption tower ⁇ is cooled by a refrigerator, so that the ozone in the ozone-containing gas is adsorbed by the adsorbent.
• Oxygen from the ozone adsorption tower is sent again to the ozone generator ⁇ by the circulation blower.
• the above-mentioned ozone adsorption work is repeated, and when the required ozone is adsorbed, the circulation blower 3 ⁇ 4, the ozone generator ⁇ ⁇ and the refrigerator ⁇ are stopped, and the control valve ⁇ ⁇ ⁇ is closed.
• the temperature raising brine pump is operated and the heating medium in the brine tank ⁇ is moved into the ozone adsorption tower ⁇ ). Into the heating fin.
• ozone desorption starts when the temperature in the tower reaches about 0 ⁇ .
• the ejector pump 8 is started, and after the ejector enters normal operation, the control valve 0 ⁇ in the ozone delivery pipe from the ozone adsorption tower ⁇ to the ejector is opened.
• the ejector reacts and mixes the ozone-containing gas with the treated water.
• the ozone concentration in the ozone-containing gas at the time of injection into the ejector 6 is about 35 weight or more. Repeat the above operation This makes it possible to inject ozone intermittently into the treated water at the required ozone concentration.
• the ozone injection concentration is controlled by controlling the above-mentioned ozone adsorption time.
• the ozone adsorption time is about 2 hours to 48 hours, and the ozone injection time is completed in 1 minute to several minutes. Both are performed by appropriately setting the timer, and the injection cycle and the injection time are, of course, dependent on the properties of the target treated water.
• the treated water containing ozone flows in the cooling water supply pipe 0) and is washed up to the roll cooling water header ( 4 ) to prevent the generation of slime.
• the ozone concentration in the roll cooling water header ( 4 ) must be at least O.ln ⁇ Z or higher, and there is no effect on the metal strip due to residual ozone I checked.
• the ozone injection concentration was set to 5 ⁇ ⁇ ⁇ £, the injection duration was kept constant for 5 minutes, and the ozone injection cycle was changed in the range of 5 hours to 72 hours. The presence / absence of a film attachment was examined. The results are shown in Table 1. Table 1
• the ozone injection concentration was 5 m / 3 ⁇ 4, the ozone injection cycle was constant at 24 hours, and the ozone injection duration was changed in the range of 10 seconds to 10 minutes. The presence of slime on the wall was examined. The results are shown in Table 2.
• Example 3 Ozone injection period as the 2 4 hours, a constant ozone injection duration 5 minutes, in the ozone injection concentration change 0.0 7 Ozon concentration in header one to roll cooling m ⁇ ⁇ 2 .3 m ⁇ of range The presence or absence of slime adhered to the inner wall of the cooling water supply pipe end was examined. Table 3 shows the results.
• the concentration By setting the concentration to 0.1 ppm or more, it is possible to completely remove and control slime and other attached organisms on the inner wall of the cooling water supply pipe. This is because ozone has a strong bactericidal effect, and if it is within a certain cycle, a sufficient slimming effect can be obtained by intermittent injection, and there is no need for continuous injection, so small ozone generation
• the required ozone concentration can be maintained by generating ozone by using a vessel, storing a predetermined amount of ozone in the adsorption tower, and injecting it into cooling water at regular intervals. It goes without saying that ozone injection may be performed continuously. In the case of continuous injection, the ozone concentration at the cooling water injection section may be 0 or more.
• the present inventor when performing roll cooling by the direct method, injects ozone into the cooling water and adjusts the ozone concentration in the cooling water at the cooling water injection section to the roll to a predetermined value. It has been confirmed that the generation of slime can be suppressed by setting preferably 0.1 ppm or more.
• Ozone not only has a higher bactericidal effect than conventional chlorine, but also has the advantage that it is decomposed into oxygen in a relatively short time and has no effect on metal strips. Ozone poses a new problem due to its ability to decompose into oxygen in a short period of time, that is, its lifetime (half-life).
• the cooling water for cooling the roll ( 3 ) of the cold rolling mill is supplied to the roll cooling water.
• ozone treatment is applied to the cooling water injected from the nozzles of the nozzle to the rolls, ozone is injected into the cooling water at several points along the water supply pipe 0) that supplies the cooling water to the roll cooling water header ( 4 ). It is characterized by maintaining the ozone concentration of the cooling water in the water supply pipe at Ol ppm or more by injection.
• an ozone generating / supplying device is used to supply ozone into cooling water in two places at the outlet of the cooling tower (7) and at an intermediate position of the water supply pipe 0). It is configured to inject from each of (15A) by ejector 6 ) and C16A).
• the ejectors 6 ) and (16A) are provided in the ozone injection pipes C17A) connected in parallel to the water supply pipes ⁇ ), respectively.
• the ejector pumps (18) and (18A) supply cooling water from the water supply pipes 0) with high pressure. Ejector ⁇ , C16A).
• the ozone generation / supply device ⁇ , C15A can be of the same structure.
• the nozzle of the roll cooling water header (4) which is the end of the water supply pipe (W), has an ozone concentration of Ol ppm or more required to prevent the adhesion of the slime to the inner wall of the water supply pipe.
• the amount of ozone injected necessary to maintain the injected cooling water is one ozone generation supply provided only at one location on the outlet side of the cooling tower (7).
• Ki de be reduced to about LZ 6 the amount of raw material oxygen likewise can be reduced to about 1/6, required to install multiple ozone generator feeder Even if the initial costs are taken into account, more economical ozone water treatment is possible.
• the present inventor has found that the half-life of ozone is greatly affected by the PH concentration of the cooling water, and as shown in FIGS. 8 and 9, the ozone half-life becomes shorter as the PH concentration becomes higher.
• PH 7.3 has a half-life of 100 seconds
• pH 7.8 to 8.0 has a half-life reduced to 25 seconds and 14
• another embodiment according to the present invention will be described. I do.
• the ozone is supplied from the ozone generating and supplying equipment to the cold water supplied to the roll cooling water header by the water supply pipe 0).
• the ozone treatment is performed by injecting the water from the acid solution tank through the control valve ⁇ through the control valve ⁇ in conjunction with the ozone injection operation by the ejector ⁇ Adjust PH concentration of cooling water by injecting acid into cooling water.
• the P H concentration of the cooling water be at least P H 6 in consideration of the effect on the rolled material and equipment.
• an ozone injection pipe ⁇ connected in parallel to the water supply pipe 0) was provided at the outlet of the cooling tower (7), and the water supply pipe was connected by the ejector pump 08). 0), the cooling water is passed through the ejector ⁇ at a high pressure.
• sulfuric acid is passed through the control valve ⁇ by the acid injection pump ⁇ linked to the operation of the ejector 6), that is, the operation of the ejector pump).
• the PH concentration of the cooling water in the water supply pipe is measured by a PH meter ⁇ at the discharge side of the water supply pump ( 9 ), and the opening of the control valve ⁇ of the acid injection pump ⁇ 1) is adjusted to the target PH concentration. Adjustment controls the injection volume.
• the cooling water by adjusting the cooling water to have a lower PH concentration, the ozone half-life can be increased, and the amount of injected ozone can be reduced.
• the first 0 Figure diameter 600 ⁇ , the cooling water in the water supply piping of length 500m supplied at a flow rate of 1800 m 3 / Hr, the water supply pipe by injecting ozone into the cooling water in the first end of the feed water pipe Fig. 10 shows the relationship between the PH value of the cooling water and the ozone injection amount when ozone treatment was performed so that the ozone concentration at the terminal reached the target value of 0.25 ppm.
• the injection amount can be reduced to about 1Z70 compared to the case of PH 7.5.
• the target ozone concentration of the cooling water supplied by the long water supply pipe is secured at the end of the water supply pipe. Therefore, the amount of injected ozone required for this purpose can be reduced, so that the amount of oxygen used as a raw material can be reduced, the ozone generation and supply device needs to be small, and the amount of electricity and other running costs can be reduced.
• the length of the water supply piping 0) is often very long. Therefore, when supplying ozone upstream of the water supply pipe 0, the time required for the roll cooling water injected with ozone to reach the end roll cooling water header 1 ( 4 ) from the ozone supply position, i.e. As the time increases, the residence time also depends on the flow rate of the roll cooling water. In general, the flow rate of roll cooling water in a cold rolling mill is controlled in accordance with the rolling speed, so that the flow rate of cooling water flowing through header pipes (0) through header (4) fluctuates.
• an ozone generating and supplying device is used for cooling water supplied to a roll cooling water header ( 4 ) by a water supply pipe do) ⁇
• a water supply pipe do ⁇
• the flow rate of cooling water during the residence time is controlled to be constant.
• ozone injection pipe 7 is connected in parallel to the water supply pipe at the outlet side of the cooling tower (7), and the ozone generator ⁇ ⁇ Ozone is connected to the ozone injection pipe?)
• the ejector ⁇ By the ejector ⁇ , and cooling water is passed through the ejector at high pressure from the water supply pipe 0) by the ejector pump ⁇ .
• a cooling water outlet pipe ⁇ is connected to the feedwater pipe 0) upstream of the end of the feedwater pipe, preferably near the header (4), and the outlet pipe ⁇ is connected to the drainage tank ( 5)
• Control the opening of the flow control valve ⁇ to maintain the ozone residence time in the water supply pipe ⁇ , that is, to keep the flow rate of the cooling water constant between the ozone injection point A and the branch connection point B of the extraction pipe ⁇ .
• the amount of water in the roll cooling water header can be performed economically and stably without being affected by water.
• the present invention it is possible to prevent the generation of slime in the cooling water supply pipe and improve the quality of the metal strip.
• the maintenance cost can be reduced by reducing the maintenance, and further, the amount of fresh water replenishment can be reduced and the running cost can be reduced.
• the present invention is applicable to a process for preventing slime formation of roll cooling water of a cold rolling mill.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)

Applications Claiming Priority (8)

Publications (1)

Family

ID=27479038

Family Applications (1)

Country Status (2)

Citations (6)

Family Cites Families (1)

• 1985
  • 1985-12-24 DE DE19853590663 patent/DE3590663T1/de not_active Ceased
  • 1985-12-24 WO PCT/JP1985/000703 patent/WO1986003698A1/ja active Application Filing

Patent Citations (6)

Also Published As

Similar Documents

Legal Events