JP2796117B2 - Local repair method for glass lining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention repairs a locally damaged portion generated in a lining glass layer of glass lining equipment used in a chemical industry, a pharmaceutical industry, a food industry, and the like. About the method.

(Conventional technology) Glass lining with a continuous glassy coating with a thickness of about 1 mm formed on the base metal surface of equipment that comes into contact with corrosive gas and liquid by repetition of fusion by high-temperature firing in a furnace The device may cause local damage to the lining glass layer due to mishandling or the like during use in the above technical field. As the corrosion of the base metal progresses rapidly from the damaged part, it is perfect to detect the damage early and send the equipment to a glass lining contractor to rebuild the glass lining, but the production line process was interrupted during that time Therefore, it is desirable to be able to perform satisfactory local repairs by a simple method that can be performed at the installation site.

Prior art local repair methods for this purpose include: (a) a method using a corrosion-resistant tantalum metal cap, bolt, or the like, and sealing the gap between the lining glass surface with Teflon packing.

(B) A method in which an organic corrosion-resistant resin such as an epoxy resin or an adhesive is applied to the damaged portion and cured.

(C) A method of spraying a corrosion-resistant metal such as Hastelloy on a damaged portion (Japanese Patent Publication No. 58-25740).

(D) A method in which a powder of a low melting point lead glass or vanadin hydrochloride glass is applied to a damaged portion and softened and fused by local heating (Japanese Patent Laid-Open No. 59-102835).

(E) A method of applying and heating a silicon alkoxide-based coating agent (JP-A-63-76887).

(Problems to be Solved by the Invention) Large-scale repair equipment is not required to enable local repair at the installation site of glass lining equipment, and a normal lining glass layer near the damaged part during repair work It is necessary to be able to repair according to the location, shape and area of the damaged part, and to obtain satisfactory repair results, no defects such as cracks and pinholes occur in the repair material layer It must have excellent chemical resistance, excellent penetration resistance, no toxicity, good adhesion to the repair area, no liquid penetration, and the repair equipment must be able to withstand the thermal cycle during actual use. is there.

In this respect, the tantalum repair method (a) of the prior art may not be able to conform to the shape of the damaged portion, and penetration may occur due to deterioration of the Teflon packing. The epoxy resin repairing method (b) has poor solvent resistance and causes water vapor diffusion in the material. In the thermal spraying method (c), the thermal sprayed layer becomes porous, and large-scale thermal spraying equipment is required. The low-melting glass method (d) has a risk of thermally damaging a nearby normal glass lining at a working temperature of about 600, and lead and vanadium are toxic. In the silicon alkoxide coating method (e), an organic substance and a carbon component in the material remain, and if an epoxy resin is used in combination, the silicon alkoxide coating method cannot withstand a heat cycle at the time of using a repair device. Therefore, it is difficult to obtain a satisfactory repair result by the conventional local repair method.

(Means for Solving the Problems) An object of the present invention is to correct the difficulties in the construction of the various local repair methods according to the prior art and the deficiencies in the construction results of the broken portion of the lining glass layer on the surface of the glass lining equipment. It was done.

In order to achieve the above object, in the present invention, a sol-gel glass repair agent is applied to a damaged portion of the lining glass layer to form an inorganic repair portion.In this case, the thermal expansion coefficient is lower than that of silicon alkoxide alone as the repair agent. Multi-component sol-gel glass, which can be made almost the same as glass lining equipment glass, iron substrate, especially
A sol-gel glass composed of sodium alkoxide, silicon alkoxide and zirconium chloride forming a Na ₂ O—ZrO ₂ —SiO ₂ multi-component glass is used. This is applied to the damaged part, and is heat-treated to a temperature below the transition of the lining glass to be reacted and solidified to form a repaired part.

The sol-gel glass repair agent remarkably shrinks when it solidifies by reaction to form glass, and this causes voids to be formed. However, the repair agent to be repeatedly applied is impregnated into the voids to fill it. The thermal expansion coefficient of the repaired part thus formed is adjusted, so that the thermal shock resistance is improved. In terms of the coefficient of thermal expansion, an inorganic filler, preferably glass powder having the same thermal expansion coefficient as that of the lining glass and preferably having the same coefficient of thermal expansion, can be used as a mixture with the above-mentioned repairing agent. The repairing agent reacts and solidifies while being impregnated into the gaps between the fillers of the inorganic powder. The water resistance and alkali resistance of the repaired part can be simultaneously improved by selecting the above-mentioned repairing agent component.

And when importance is attached to the iron base of the damaged part,
Only the first layer of the repaired portion can be repaired with a repairing agent that forms a phosphate glass instead of the repairing agent.

In sum of these solutions, the method for locally repairing glass-lined equipment according to the present invention comprises, as a configuration, a method for repairing a locally damaged portion generated in a lining glass layer of a glass-lined device with an inorganic material, so that the vicinity of the damaged portion is repaired. Na ₂ O-Zr whose thermal expansion coefficient is almost the same as that of the normal lining glass layer of
Using a sol-gel glass aqueous solution of sodium alkoxide, silicon alkoxide and zirconium chloride to form an O ₂ —SiO ₂ multi-component glass as a starting material, using a repair agent optionally mixed with an inorganic filler before gelation, And applying a heat treatment to a temperature lower than the transition point of the lining glass after the application to cause the reaction to solidify to form a repair layer.

Further, the present invention provides a modified embodiment of the sol-gel glass repair agent which uses an aqueous solution of a metal alkoxide as a starting material to form a phosphate glass having excellent adhesion to an iron substrate prior to the repair work using the repair agent. The construction method of forming the first repair layer using the method is included.

Hereinafter, in order to further clarify the gist of the method of the present invention, the steps will be generally described in detail in accordance with typical examples with reference to the accompanying drawings. However, the present invention is not limited by these examples.

[I] repairing agent adjustments (I-1) forming a basic repair agent A damaged portion of the most comparable normal lining glass layer and the thermal expansion coefficient near Na ₂ O-ZrO ₂ -SiO ₂ system multicomponent glass The following components and composition ratios are selected and adjusted in consideration of the corrosion resistance of the basic repair agent A to be used.

Sodium ethoxide [Na-OEt] silicon tetraethoxide [Si- (OEt) _4] zirconium chloride oxide octahydrate [ZrCl ₂ O-8H ₂ O] ethanol [Et OH] [H ₂ O] water [H ₂ O The adjustment is performed by putting ethanol and water into a glass beaker, adding other ingredients, and stirring and mixing with a stirrer at 25 ° C. for 30 minutes to obtain a transparent basic repair agent A.

(I-2) Repair by mixing a basic repair agent A with an inorganic filler powder, preferably a glass powder of the same or equivalent quality as the lining glass, or a ceramic powder having no difference in thermal expansion coefficient and corrosion resistance or equivalent. Agent A1.

(I-3) When the method of the present invention is carried out in a modified mode, an organometallic compound represented by a metal alkoxide and an alkali phosphoric acid are separately placed in an aqueous phosphoric acid solution, and the mixture is distilled while being heated and stirred, and the viscous transparent repair is performed. Agent B is prepared.

[II] Repairing process (II-1) The damaged portion is polished and shaped by a grinder or the like to expose the metal base and is cleaned with an organic solvent or the like.

(II-2) A repair agent A1 is applied to the damaged portion. The first layer may be coated with a repair agent B.

(II-3) After air drying for 10 minutes, 350 ° C using an electric heater
For 10 minutes to solidify the reaction and form one repair layer.

(II-4) The steps II-2 and II-3 are repeated until the repaired part has a predetermined thickness.

(II-5) A repair agent A is applied to the repair layer to impregnate the lower layer, and a heat treatment equivalent to II-3 is performed. This process is repeated about five times.

In this manner, as shown in FIG. 1, the lower repair layer (3) which is in close contact with the iron base material at the damaged portion of the normal lining glass layer (2) on the base metal (1) of the glass lining equipment, and has a thicker layer thereon. Na ₂ O consisting of the upper repair layer (4)
Forming a -ZrO ₂ -SiO ₂ system multicomponent glass repair unit.

(Action) In the present invention, the lower repair layer (3) of the repair portion is formed by the repair agent A-
In the case of forming by using No. 1, a film having good adhesion is formed in which a hydroxyl group (-OH group) on the surface of iron oxide slightly formed on the surface of iron and others and a highly hydrophilic alkoxide solution are chemically bonded. You. The same applies to the case where the repair material A containing no filler is used, and the repair material B is used to simultaneously form a chemically reactive layer of iron phosphate at the interface with the iron substrate, thereby further strengthening the bonding of the lower repair layer (3). It can also be done.

The upper repair layer (4) following the lower repair layer (3) is constructed with the repair material A-1 in which the filler powder is compounded.
The repair material A solution impregnates and solidifies a small gap portion of the filler particles, and the gap created by the solidification shrinkage is additionally filled with the repair agent A by repeated impregnation and solidification. Obtained as an excellent thick film.

A metal alkoxide alone, for example, a silicon alkoxide alone can produce only silica glass having low alkali resistance, but the Na ₂ O--ZrO ₂ --SiO ₂ multi-component glass formed according to the present invention also has excellent alkali resistance, If a material having corrosion resistance and desired characteristics required for a glass lining device is selected, a repaired part having excellent corrosion resistance in general and having desired characteristics is formed.

Also the Na ₂ O-ZrO ₂ -SiO ₂ multi-component glass system repair portion is much higher 100 × 10 ^-7 ° C. of about ^-1 compared to 5 × 10 ^-7 ° C. ^-1 silica glass repair unit thermal expansion coefficient You can get close to that of iron-based material. Generally, in glass lining equipment,
As can be seen from the thermal expansion curve comparison diagram in FIG. 2, the lining glass layer has a compressive stress remaining at room temperature due to a difference in thermal expansion, and the composite is strengthened. However, when reheated for repair work, the compressive stress decreases. When the temperature exceeds the 350 ° C transition point, tensile stress acts. In the present invention, since the heat treatment is performed to near the transition point temperature in order to strengthen the bonding force of the repairing agents A-1 and A, the bonding force is enhanced and the coefficient of thermal expansion is adjusted to be close to that of the iron base material. Therefore, even during a thermal cycle when using the repair equipment, the repair part expands and contracts following the iron base material well, and also has excellent heat cycle resistance and thermal shock resistance.

(Example) (I) Example I for peelability test The coefficient of thermal expansion (100 × 10 ⁻⁷ ) is slightly smaller than iron of the base metal.
° C. Na ₂ are components adjusted so as to have a ^-1) O-ZrO ₂ -SiO ₂
Repair agent A was prepared with the formulation in Table 1 below to form a multi-component glass.

Table 1 repairing agent A formulation (unit gr) of sodium ethoxide [Na-OEt]: 0.5 zirconium chloride oxide octahydrate [ZrCl ₂ O-8H ₂ O]: 1.0 silicon tetraethoxide [Si- (OEt) _4] : 8.5 ethanol [Et OH] [H ₂ O]: 10.0 water [H ₂ O]: 8.0 adjusted first put ethanol and water in a glass beaker
The other raw materials in the table were charged and stirred with a stirrer at 25 ° C. for 30 minutes to obtain a transparent basic repairing agent A.

The repair agent A is mixed with a filler of glass powder or ceramic powder having good corrosion resistance and a thermal expansion coefficient similar to that of the normal lining glass portion around the repair portion.
1 was obtained.

After producing a test piece of 2.5 × 100 × 100 mm in size with glass lining corresponding to JIS R 4201 on SS41 iron base, the lining glass layer in the center part was removed with a grinder, and a broken part with a diameter of 40 mm was simulated. It was produced in a typical manner.

The exposed damaged portion of the iron base was degreased with ethanol, and then wiped off with a dry cloth.

 The repair agent A-1 was applied to the iron base.

After air-drying for 10 minutes, it was heat-treated at 350 ° C. for 10 minutes using an electric heater.

The above operation is repeated a required number of times to form a repair layer having a required thickness.

Further, the operation of applying and impregnating the above-mentioned layer with the repairing agent A and performing the same heat treatment as described above was repeated 5 times.

Note it was confirmed that the separately above series of operations by 4φ × 20mm prefabricated to 100 × 10 ^-7 ° C. was measured and the thermal expansion coefficient of the rod-like sample of healing agent ^-1. This coefficient of thermal expansion is slightly smaller than that of the iron base material. Therefore, the compression pressure remains in the repaired portion at room temperature and the composite portion is reinforced.

Using the evaluation test apparatus according to JIS R4201, the above-mentioned repair test piece was subjected to a peeling test by repeating a heat cycle of 5 hours in boiling water and cooling to room temperature and 5 hours.

After 6 months, no peeling of the repair glass layer and no cracks in the repair glass layer were observed.

(II) Example II for permeability test A test piece was prepared by carrying out the method of the present invention in the same manner as in Example I.

The permeability test was carried out in the same manner as in Example I except that 0.1 N hydrochloric acid was used instead of water in the peeling test, and the other conditions were the same.

After 6 months, the acid solution and the repaired portion did not turn brown, and it was judged that there was no corrosion of the iron substrate due to the permeation of the hydrochloric acid solution.

(III) Example III for Water Resistance Test A test piece was prepared by carrying out the method of the present invention in the same manner as in Example I for a base metal of 2 × 100 φmm SUS 304 stainless steel plate.

In a one week test, the corrosion thickness was less than 0.5 mm / year.

(IV) Example IV for Adhesion Test with Iron Substrate IV Example 1 Using SS41 Steel Sheet of Dimensions 6 × 80 × 80 mm as Base Metal
A test piece was prepared by carrying out the method of the present invention in the same manner as described above.

An adhesion test was performed according to JIS R4201. That is,
A steel ball having a diameter of 36.51 φmm (weight about 200 gr) was naturally dropped vertically from a height of 45 cm, and the state of peeling of the coating was examined. As a result, no crack reaching the iron base was observed at the repaired portion according to the method of the present invention.

(V) Example V for Actual Can Body Test An open tank made of glass lining with a capacity of about 100 tons shown in JIS R 4201 was prototyped, and the lining glass layer on the inner surface of the tank was polished and removed over an area of about 100 cm ^2. Thus, a simulated damaged portion having a large area was prepared, and repaired by the method of the present invention in the same manner as in Example I.

Cracks and the like did not occur in the lining glass layer around the repaired part.

(VI) Example VI for Actual Can Body (Example of a Location Where Repair is Difficult) Repair of a convex round portion having a radius of curvature of 6 Rmm of the flange portion of the tank of Example V was performed in the same manner as Example V.

No cracks or the like occurred in the normal lining glass layer around the repaired part.

In addition, the corrected portion was subjected to the same adhesion test with an iron base material as in Example IV, and as a result, no crack or the like was found in the repaired portion.

(Effects of the Invention) As described above, according to the method of the present invention, a locally damaged portion generated in a lining glass layer of a glass lining device used for chemically and thermally severe environmental conditions is provided. Sound repair can be easily performed at low cost.

In particular, the condition required for the repair material, chemical resistance, immersion resistance, adhesion, and heat cycle resistance are excellent, so that the soundness of the repaired portion is maintained over a long use period of the device. In addition, a filler and an impregnated repair agent of a desired material can be selected, for example, by adjusting a coefficient of thermal expansion to improve thermal shock resistance, so that the applicable range is wide. In addition, the repair can be carried out economically using relatively simple tools at the installation site of the glass lining equipment. In addition, there are almost no restrictions on application due to the form of the repaired part.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a local portion schematically showing a lining glass layer according to the method of the present invention, and FIG. 2 is an example of the relationship between the temperature of the horizontal axis of the iron base material and the lining glass layer and the material elongation on the vertical axis. FIG. (1) ... base metal, (2) ... lining glass layer,
(3) ... lower repair layer, (4) ... upper repair layer.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23D 13/00 C03C 8/00

Claims (2)

(57) [Claims] In order to repair a locally damaged portion generated in a lining glass layer of a glass lining device with an inorganic material, Na ₂ O— having almost the same thermal expansion coefficient as a normal lining glass layer around the damaged portion is used. Using a sol-gel glass aqueous solution of sodium alkoxide, silicon alkoxide and zirconium chloride forming a ZrO ₂ -SiO ₂ multi-component glass as a starting material, and using a repair agent optionally mixed with an inorganic filler before the gelation, Local repair of glass lining equipment characterized by applying a process of applying a heat treatment to a temperature not higher than the transition point of the lining glass after application to form a repair layer by applying a heat treatment to a temperature lower than a transition point of the lining glass, and performing a repetitive construction. Method. 2. A first repair using a sol-gel glass repair agent starting from an aqueous solution of a metal alkoxide which forms a phosphate glass having excellent adhesion to an iron substrate prior to the repair work using the repair agent. 2. The method according to claim 1, wherein the layer is formed.