DE3022924A1 - METHOD FOR REMOVING BOILER - Google Patents

Description

The invention relates to a method for removing in aqueous systems »e.g. boiler water systems» cooling water systems and the like » seasoned and from used Water-derived scale.

It is extremely common »that in aqueous systems» e.g. boiler water systems, cooling water systems and the like. » Operational malfunctions, e.g. impairment of the thermal efficiency or local corrosion »due to scale and / or sludge deposition. These disturbances occur in particular on the heating surfaces of such aqueous systems. The reason why scale or sludge is formed is obviously to be seen in that impurities contained in the water, e.g. calcium »magnesium» silicic acid and the like, are concentrated and consequently on surfaces in contact with the water, especially heating surfaces, calcium carbonate, hydroxyapatite » Magnesium silicate and the like are deposited.

In addition, medium and low pressure boilers are becoming more and more compact and powerful. Pollich rise at These boilers compared to conventional boilers the evaporation rate on the heating surfaces and the heat load the firing is extraordinarily strong. As a result of such an increased heat load on the heating surface, the in the water Contained impurities even more concentrated, so that a stronger scale deposition takes place than usual. Even a small scale deposit causes the

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Risk of accidents due to expansion and bursting of evaporation pipes. For these reasons, an effective prevention of scale formation or scale * - more and more attention should be paid to the distance.

Scale usually consists of calcium carbonate, hydroxyapatite Magnesium silicate, iron oxide and the like. Scale containing these substances is in most cases inorganic Acids »e.g. hydrochloric or sulfuric acid» soluble. In view of this, the scale removal has been carried out so far by temporarily switching off the boiler to lower the temperature and then cleaning it with a Inorganic acids such as hydrochloric acid and the like. The disadvantage of this acid cleaning, however, is that the system takes a long time is exposed to strong acid attack. Furthermore, there are also general possible dangers when handling acids. Finally, cumbersome precautions are required to safely drain the acid solution after cleaning.

In view of this, chelating agents such as nitrilotriacetic acid salts have already been used to eliminate the disadvantages mentioned. used, although these are inferior to inorganic acids in terms of dissolving scale are. Such chelating agents have a pungent odor, corrosive metals, make it difficult to control the boiler operation and the like. In addition, when using such chelating agents, not even all of the usual ones can be used Eliminate the disadvantages inherent in the process »i.e. even when using such chelating agents, boiler operation must be intermittent interrupted »to drain the total amount of boiler water.

A process has also already been developed in which the boiler scale can be removed without stopping the boiler operation of a polyacrylate is removed. With the help of the polyacrylate

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can be composed of calcium carbonate and / or calcium silicate Certainly remove scale to a certain extent »the disadvantage of the polyacrylate is, however, that hardly consists mainly of hydroxyapatite Limescale, as it occurs most frequently in boilers, can be removed.

The invention was based on the object of providing a method that can be carried out without stopping the operation of the system Removal of calcium carbonate, hydroxyapatite, magnesium silicate and the like. Existing and in aqueous systems, e.g. boiler or cooling water systems, in particular other Heating surfaces to develop deposited scale.

The invention therefore relates to a process for the removal of substances in contact with aqueous systems Surface deposited scale, which is characterized in that it gives the aqueous system an effective Amount of an itaconic acid polymer having 75 to 100 mol # of itaconic acid units (A), 0 to 25 mol # of units a further unsaturated carboxylic acid (B) and / or unsaturated monomer units, which differ from the unsaturated Differentiate carboxylic acid (C), adds.

In the itaconic acid polymer which can be used according to the invention it is a question of homopolymers or copolymers of itaconic acid, including its anhydride or its water soluble salts. Itaconic acid homopolymers or copolymers are, for example, those with 75 to 100 mol # of itaconic acid units and 0 to 25 mol% of further unsaturated monomer units.

Unsaturated monomers, the units of which can be contained in itaconic acid polymers which can be used according to the invention, are for example -unsaturated carboxylic acids, including their anhydrides, e.g. monoethylenically unsaturated

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te homo- or polycarboxylic acids, such as (meth) acrylic acid (ie acrylic acid or methacrylic acid) »maleic acid» maleic anhydride »fumaric acid and the like» unsaturated sulfonic acids such as aliphatic or aromatic vinyl sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, vinyl toluene sulfonic acid, styrene sulfonic acid and the like. Monomers containing hydroxy groups, for example monoethylenically unsaturated alcohols such as (meth) allyl alcohol, monoethylenically unsaturated ethers or esters of polyols such as alkylene glycols, glycerol, polyoxyalkylene polyols, hydroxyalkyl (meth) acrylates, for example hydroxyethyl (meth) acrylate, hydroxypropyl (meth ) acrylate, triethylene glycol (meth) acrylate, hydroxyethyl itaconate, etc., polyethylene glycol mono- (meth) allyl ether, monomers containing amide groups, for example (meth) acrylamide, 3J-alkyl (meth) acrylamides, such as N-methylacrylamide and N-hexylacrylamide , N, N-dialkyl (methacrylamides, such as N, N-dimethylacrylamide and N, N-di-n-propylacrylamide, N-hydroxyalkyl- (meth) acrylamides, such as N-methylol- (meth) acrylamide and N-hydroxyethylr ( meth) acrylamide »N, N-dihydroxyalk yl (meth) acrylamides, such as N »N-dihydroxyethyl (meth) acrylamide, vinyl lactams, for example N-vinylpyrrolidone, unsaturated carboxylic acid esters, for example alkyl (C.-C ₁ g) esters of monoethylenically unsaturated carboxylic acids, such as (methacrylic acid, Maleic acid, fumaric acid, itaconic acid and the like. For example methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like, esters of monoethylenically unsaturated 'Alcohols, e.g. vinyl esters and (meth) allyl esters, such as vinyl acetate or (meth) allyl acetate, unsaturated nitriles, e.g. acrylonitrile, aromatic vinyl compounds such as styrene and the like. Preference is given to unsaturated dicarboxylic acids and unsaturated sulfonic acids, especially vinylsulfonic acid, styrene sulfonic acid, (meth) acrylic acid and maleic acid including their anhydrides.

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The amount of itaconic acid units (A) in the itaconic acid polymer in the case of the presence of unsaturated carboxylic acid units (B) is generally 75 mol # or more »expediently 80 mol # or more, preferably 90 mol # or more (in each case based on the total monomer units). The remainder consists of monomer units (B) in the case of the presence of other unsaturated monomer units (C) as unsaturated carboxylic acid units, the amount of itaconic acid units (A) is 75 mol # or more, expediently more than 90 mol-56 (e.g. 91 mol- # or more), preferably 95 mol # or more (based in each case on the total monomer units). The rest consists of Monomer units (C).

The amount of the unsaturated carboxylic acid units (B) in the itaconic acid polymer or its water-soluble one Salt is 25 mol # or less, preferably 10 mol # Or less.

The amount of unsaturated monomer units (C) other than unsaturated carboxylic acid units is 25 moles-96 or less »suitably less than 10 mole #, for example 9 mole # or less, in particular 5 mol% or less.

In the case of the simultaneous presence of unsaturated monomer units (B) and (C), the amount of itaconic acid units (A) is 95 mol # or more. The rest exists then from unsaturated monomer units (B) plus (C). In this case, the amount of unsaturated monomer units is (C) preferably less than 10 mole #.

The molecular weight of itaconic acid polymers which can be used is generally 1,000 to 200,000, preferably 3,000 up to 50,000.

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^::: V; fr 3022824

The Itaconsaurepolymerisate are obtained for example by polymerizing itaconic acid and, if necessary other so misehpolymerisierbarer monomers at a temperature of 40 to 15O ⁰ Ct preferably from 50 to 90 ⁰ C, in the presence of a conventional polymerization initiator of the peroxide type "eB benzoyl peroxide, azo-type, such as azobis -isobutyronitrile »of the persulfate type, such as sodium persulfate, etc. The polymerization can be carried out, for example, in aqueous solution.

In the itaconic acid polymers which can be used according to the invention it can also be their water-soluble salts, e.g. alkali metal salts such as sodium, potassium or lithium salts, Ammonium salts, amine salts such as triethanolamine salts, and the like. as well as mixed salts. The alkali metal salts are preferred. The water-soluble salts of itaconic acid polymers is obtained either by polymerizing the previously salted monomer or by converting the previously polymerized monomers into a salt. The water-soluble salts of the itaconic acid polymers are according to the invention the latter preferred.

The process according to the invention for removing scale can be carried out with the itaconic acid polymer or its water-soluble Salt alone can be used, but better results are obtained using it together with an acrylic acid polymer "or its water-soluble Salt.

Acrylic acid polymers which can be used according to the invention are homopolymers or copolymers of (meth) acrylic acid or their water-soluble salts. Further monomers which can be polymerized with the (meth) acrylic acid are already named monomers copolymerizable with itaconic acid and itaconic acid or its water-soluble salts.

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The molar ratio of (meth) acrylic acid or its water-soluble The salt to the other monomers can be chosen as desired, the amount of (meth) acrylic acid or its water-soluble Salt is usually greater than 50 molar g, preferably more than 70 mol # (based on the acrylic acid polymer). The acrylic acid polymers which can be used according to the invention generally have a molecular weight of 1,000 to 100,000, preferably 2,000 to 50,000. Water-soluble Salts of acrylic acid polymers are the same like the water-soluble itaconic acid polymer salts. The alkali metal salts are also preferred here.

The amount of in the process according to the invention The scale remover that can be used depends somewhat on the composition of the scale or scale scale-forming components of the water, the amount of scale deposited and the like., from. Usually amounts to this amount 1 to 1000 mg / l.

The mixing ratio of itaconic acid polymer or water-soluble Salt of the same to acrylic acid polymer or the water-soluble salt thereof, depending on the composition the scale deposited in the special system, especially the amounts of calcium carbonate and hydroxyapatite, can be varied within wide limits. Per 100 parts by weight of the itaconic acid polymer or the water-soluble salt of the same, the amount of acrylic acid polymer or water-soluble salt thereof is usually 5 to 1000, expediently 10 to 200, preferably 20 to 50 parts. The costs can be reduced without lowering the operating efficiency, in particular if the amount of Acrylic acid polymer or the water-soluble salt thereof is 5 to 1000 parts by weight. The amount of itaconic acid (Salt) in the sum of itaconic acid polymer and aoryl acid polymer is generally 20 mol #, preferably 40 to 90 mol-Ji.

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In the case that the _f Itaconsäurepolymerisat wasserlöelicheB or its salt is used in combination with the acrylic acid polymer or its water-soluble salt, both components can be premixed and then incorporated together to be treated aqueous system, or added separately in a suitable quantity.

The aqueous systems to be treated according to the invention are systems in which scale is formed e.g. boiler water systems, cooling water circulation systems, multi-water evaporation systems, Systems for the concentration of waste liquids, aqueous systems that act as dust collectors the exhaust gas cleaning are used and the like. Such systems can best be treated with those with heating surfaces are in contact, e.g. boiler feed water systems and the like.

The method according to the invention is carried out in such a way that beyond the tolerable limit on with the Boiler and other equipment surfaces in contact with water Point in time at which cleaning is required) at an elevated temperature, for example at the operating temperature the system with the water contained therein with the scale removal agent that can be used according to the invention is treated.

In the case that the scale removal method according to the invention is for removing scale from a boiler is used, you can of course also temporarily stop the boiler operation and then the boiler scale remove in the usual known manner. Most beneficial, however, is the scale removal process of the present invention to remove without stopping boiler operation. In other words, when the operating

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Borrowed boiler is ready to be cleaned, the usable according to the invention Scale remover added to the boiler feed water for a while while the boiler continued to operate will. As a result, the vapor formed does not have any pungent odor caused by the admixture of chemicals and that mainly consists of calcium carbonate, iron oxide, calcium silicate, hydroxyapatite and the like the scale removal agent used is completely removed. The scale removed in this way will be removed from the System removed along with the drained water.

The point in time at which the scale removing agent used in the invention is added depends on the Type of system and the like. Preferably it should be added at a time when the scale is up to a height of 0.01 mm or more, in particular 0.05 now up to 0.5 dim, is deposited.

The treatment temperature when using the scale remover normally corresponds to the operating temperature of the plant. If the treatment is carried out after the shutdown of the plant, as it can be carried out as the operating temperature of the plant, for example at a temperature in the range of 10 ° to 200 ⁰ C, or at the same or a different temperature. The treatment time when using the scale removal agent according to the invention depends on the treatment temperature and the amount of scale deposited, normally it lasts from 10 days to 60 days.

Usually boilers are cleaned once a year. This also applies in cases in which for this purpose the invention usable scale removal agent is used. Preferably, the scaling is removed more often, for example once a month or once in several *) existing scale

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Months. In this case the scale removal is more effective » since the amount of deposited boiler is small.

In addition, the scale removal can also be performed periodically Boiler repair or maintenance work is carried out.

The same of course also applies to the removal of scale formed in cooling water systems and the like.

The scale removal process according to the invention is suitable for removing scale in aqueous systems » who do not have a scale inhibitor or at least one scale inhibitor in the form of an acrylic acid polymer »maleic acid polymer, Amide polymer, a phosphorus compound or one for the formation of polyvalent metal ions was added in water-capable polyvalent metal compounds. Usable acrylic acid polymers »phosphorus compounds and polyvalent metal compounds are, for example, from DE-OS 26 43 422, maleic acid polymers GB-PS 1 414 918 or 772 775 and US-PS 2 723 956 and amide polymers from US-PS 3 928 186 and 3 692 673 known.

Within the scope of the scale removal process according to the invention, it is also usually possible in boilers and cooling water systems chemicals used, e.g. alkaline agents such as sodium hydroxide, potassium hydroxide, morpholine, cyclohexylamine and the like, corrosion inhibitors such as phosphates, hydrazine, triethanolamine, organic acid salts, chelating agents such as Ethylenediaminetetraacetic acid and the like. " and bactericides such as hypochlorous acid and the like may be present.

With the aid of the scale removal process according to the invention, hydroxyapatite,

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Calcium carbonate »Remove magnesium silicate and similar existing scale * without stopping the respective system must become. Rather, the operation can be safely continued without impairing the thermal efficiency.

The following examples are intended to illustrate the invention in more detail.

example 1

The scale removal process according to the invention is carried out using an internally heated autoclave with a steam outlet » a water supply and an electric heating pipe tested for its performance.

The autoclave is operated for 3 days under the following conditions:

Concentration multiple: 10. Pressure: 981 kPa.

Feed water: Tap water from Yokohama with 200 mg / 1 sodium hydroxide .

pH value of the water in the autoclave: 11.5 to 11 »7.

After 3 days, the heating tube is removed from the autoclave for observation. It can be seen that the entire surface of the heating tube is covered with hard scale * uf 65 % calcium carbonate, 15% calcium silicate and 8% magnesium silicate.

Then the autoclave is filled with softened Yokohama tap water for 2 days as feed water and 100 mg / 1 of the scale remover mentioned in Tables I to III below

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medium operated. The degree of scale removal is calculated is derived from the following equation:

Amount of boiler removed - percentage scale in g

Stone removal rate _amount ^ g _{at ela} g _he tem boiler

_g g seistein in g

This scale removal test is carried out with the various scale removal agents [in each case in the same way .

The degree of scale removal achieved in each case is also given in Tables I to III.

Table I contains the results using itaconic acid homopolymers and blank tests and the usual ones Scale removal process »Table II contains the results when using itaconic acid copolymers, Table III contains the results when itaconic acid and acrylic acid polymers are used together.

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TABLE I.

Boiler removal means Amount of discharged Amount of removed percentage

ω
ο
ο
σ>

Blank sample

Sodium tripolyphosphate
(Comparative experiment;

Sodium polyacrylate

a molecular weight of 4,500

(Comparison test)

Itaconic acid homopolymer with a molecular weight of 2,000

Itaconic acid homopolymer with a molecular weight of 3,000

Itaconic acid homopolymer with a molecular weight of 4,500

Itaconic acid homopolymer with a molecular weight of 50,000

Itaconic acid homopolymer with a molecular weight of 100,000 gertem scale in g

7.25

7.12

tem scale
in g

0.07

l degree of scale removal

0.98

7.31 5.50 75.2 7.38 5.70 77.2 7.19 6.85 95.3 7.23 7.22 99.9 7.29 6.91 94.8 7.34 5.58 76.0

Scale removers
Monomer (A) Monomer (B) Maleic acid
anhydride TABLE II MoI-Jt
(AWAY) Amount of ab
stored boiler
stone in g Itaconic acid Vinyl acetate 25:75
50:50
75: 25 * 7.18
7.09
7.15 Itaconic acid Acrylamide 25:75
50:50
75: 25 *
91: 9 * 7.20
7.24
7.26
7.40 0300 Itaconic acid Acrylic acid 25:75
50:50
75: 25 * 7.19
7.11
7.18 σ>
* ^
O Itaconic acid Styrene 25:75
50:50
75: 25 *
90:10 * 7.30
7.25
7.19
7.20 709 Itaconic acid Styrene sulfone
acid 25:75
50:50
75: 25 * 7.19
7.08
7.27 Itaconic acid 25:75
50:50
75: 25 *
91: 9 * 7.19
7.18
7.22
7.20

Amount of scale removed in g

3.76
3.55
6.87

2.52
4.08
6.27
7.35

2.31

3.4

6.31

3.72
3.90
7.11
7.20

2.24
3.23
6.38

2.96
3.73
6.99
7.20

scale removal percentage

52.4 50.1 96.1

35.0 56.3 86.4 99.3

32.1 47.9 87.9

51.0

53.8

98.9

100.0

31.2 45.6 87.8

41.2

51.9

96.8

100.0

co O K)

♦ according to the invention

K)

TABLE III Scale removing agents

Qi O OT • P- ^ »O -4 O CD

Itaconic acid homopolymer with a molecular weight of 4,500 (I): Sodium polyacrylate with a molecular weight of 4,500 (II) = 3: 1

(I): (II) = 1: 1

(I): Acrylic acid (90) »- methacrylic acid (10) copolymer a molecular weight of 10,000 = 3: 1

Itaconic acid (95) -acrylic acid ^ copolymer a molecular weight of 6000 (I ') (II) = 3: 1

(Ι ·) :( ΙΙ) = 2: 1 amount of dump- amount of de- percentage fermented boiler- remote boiler- boiler stone in g stone in g removal-

Degree

* The numbers in brackets "denote the molar ratios

7.38 skills 7.30 98.9 ι 7.26 6.47 89.1 VO
I. 7.19 6.94 96.5 7.41 7.39 99.7 7.19 6.89 95.8 OJ
CD
NJ
NJ
CD
NJ

From the tables it follows that with the help of the invention Scale removal process consisting essentially of calcium carbonate and calcium silicate Removes scale far better than a conventional scale removal process using sodium polyacrylate.

example

The scale removal process of the invention is similar to Example 1, with the exception that the 100 mg / l trisodium phosphate are also added to the feed water, examined for its performance.

In this case, it appears that a hard scale from 67 $> hydroxyapatite, 13% magnesium silicate and the like is formed..

The results of scale removal using appropriate scale removal agents such as they were used in Example 1 can be seen from the following Tables IV to VI. '

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TABLE IV

Kes stone remover

Blank sample

Sodium tripolyphosphate
(Comparison test)

Sodium polyacrylate with a molecular weight of 4,500 (comparative experiment)

Itaconic acid homopolymer with a molecular weight of 2000

Itaconic acid homopolymer with a molecular weight of 3000

Itaconic acid homopolymer with a molecular weight of 4500

Itaconic acid homopolymer with a molecular weight of 50,000

Itaconic acid homopolymer with a molecular weight of 100,000

Amount of scale deposited in g

2.88 2.75 2.64 3.04 2.75 3.04 3.12

2.75

Amount of de-percentage scale removed in g degree of distance

0.01
0.40
1.18
2.18
2.48
2.33
1.01

0.4 15.2 38.8

79.3 81.6 74.7 36.7

TABLE V

Scale removers
Monomer (A) Monomer (B) Maleic acid
anhydride MoI-Ji
(AWAY) Amount of ab
stored boiler
stone in g Amount of ent
distant boiler
be in g percentage
Kesselsteinent
distance degree Itaconic acid Vinyl acetate 25:75
50:50
75: 25 * 2.98
2.94
2.98 0.75
0.84
2.29 25.2
28.6
76.8 Itaconic acid Acrylic acid 25:75
50:50
75: 25 *
91: 9 * 2.82
2.91
2.96
3.02 0.31
0.45
2.10
2.44 11.0
15.5
70.9
80.8 Itaconic acid Styrene sulfone
acid 25:75
50:50
75: 25 *
90:10 * 3.19
3.00
2.97
3.11 0.48
0.54
2.32
2.80 15.0
18.0
78.1
90.0 Itaconic acid 25:75
50:50
75: 25 *
91: 9 * 3.02
2.90
2.91
2.83 0.41
0.48
2.25
2.53 13.6
16.6
77.3
89.4

* according to the invention

TABLE VI

Scale removers

Amount of dumped amount of de- percentage removed boiler scale in g stone in g distance

Degree

approx
ο
ο

Itaconic acid homopolymer with a molecular weight of 4,500 (I):
Sodium polyacrylate with a molecular weight s of 4,500 (II) = 3: 1

(I): (II) = 1: 1

(I): Acrylic acid (90) * - methacrylic acid (10) copolymer a molecular weight of 10,000 = 3: 1

Itaconic acid (90) -acrylic acid (10) copolymer with a molecular weight of 6000
(I »): (II) = 3: 1

(I "): (II) = 2: 1

2.55
2.70

2.05

2.41
2.55

97.7 86.5

93 »6

96.0 90.7

♦ The numbers in brackets indicate the molar ratios

The results show * that this is commonly used Sodium polyacrylate is nearly ineffective in removing hydroxyapatite-type scale. With With the aid of the itaconic acid derivatives which can be used according to the invention, acceptable degrees of scale removal can be achieved.

example

A water tube boiler previously treated with phosphate

2
Heating area of 178 m is cleaned according to the invention.

First, the boiler operation is temporarily stopped before cleaning in order to inspect the inside of the boiler. This shows that the entire inner wall surface is covered with a milk-white scale. The thickness of the scale, determined with the aid of a scale thickness meter, is 0.5 to 1.1 mm on the upper drum and 0.2 to 0.7 mm on the lower drum. An analysis of the constituents shows that this scale contains mainly 66 μl of hydroxyapatite and 13 % of calcium silicate.

After restarting the boiler, an itaconic acid homopolymer is continuously added to the feed water Molecular weight of 4,500 supplied in an amount of 35 mg / l.

Operation continues for over a month and then stopped again to examine the inside of the boiler. Here It is found that there is a small amount of scale remaining near the water supply pipe of the upper drum is that the scale on the lower drum wall is completely removed.

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Example 4

ρ A fire-heated boiler with a heating surface of 37 »5 m becomes

freed from scale according to the invention.

This boiler has not been treated with any chemicals for three years. Then the boiler operation becomes temporary set to unlock the boiler. It can be seen »that the entire inner wall surface with 0.6 to 1.7 mm thick, covered with white scale.

Analysis of the scale shows that it consists of 45% of calcium carbonate, 35 fi of calcium silicate, 15% and 5 $ Magnesiumsiliat other constituents.

The boiler is now started up again, with 75 mg / l of a scale remover consisting of 75 μl of sodium polyacrylate and 25% of sodium polyacrylate being continuously fed into the feed water. The boiler operation is maintained for 1 month if this condition is maintained.

Thereafter, the boiler operation is interrupted and the boiler is unlocked in order to examine its interior. On the drum no more scale can be detected in the heating pipes and the smoke pipes of the boiler.

The scale removal process of the present invention can also be used with locked kettles with excellent results carry out. In view of this, the progressiveness of the method according to the invention lies in the Hand.

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Claims (20)

PATENT CLAIMS 1. Process for the removal of on with aqueous systems in Contact standing surfaces of deposited scale, characterized in that one of the aqueous system effective "amount of an itaeonic acid polymer with 75" to 100 mol # itaconic acid units (A), 0 to 25 mol # units a further unsaturated carboxylic acid (B) and / or unsaturated monomer units, which differ from the unsaturated Differentiate carboxylic acid (C), adds. 2. The method according to claim 1, characterized in that an itaconic acid polymer is used in which the amount on the units (C) is below 10 mol #. 3. The method according to claim 1, characterized in that an itaconic acid polymer is used as units (B) (meth) acrylic acid, maleic acid, maleic anhydride and / or contains pumaric acid units. 4. The method according to any one of claims 1 or 2, characterized in that an Itaconsäurepolymerieat is used, 0300Θ4 / 0709 the sulfonic acid units unsaturated as units (C) contains. 5. The method according to claim 4ι, characterized in that an itaconic acid polymer is used as units (C) vinylsulphonic acid and / or (meth) acrylsulphonic acid units contains. 6. The method according to claim 1 »characterized» that the itaconic acid polymer in the form of a water-soluble Brings salt to use. 7. The method according to claim 6 »characterized» that * one is an alkali metal salt of itaconic acid polymer used. 8. The method according to claim 1, characterized in that an itaconic acid polymer having a molecular weight of about 1,000 to 200,000 is used. 9. The method according to claim 1, characterized in that one itaconic acid polymer together with an acrylic acid polymer or its water-soluble salt is used as a scale removing agent. 10. The method according to claim 9, characterized in that one is an acrylic acid polymer or its water-soluble Salt used containing essentially 50 to 100 (meth) acrylic acid units and 0 to 50 mol # of others Contains unsaturated monomer units. 11. The method according to claim 9 »characterized in that the itaconic acid polymer and the acrylic acid polymer or its water-soluble salt in a weight ratio 100: 5 tie 1000 to use. 030064/0709 'V: - ""! Γ: - 3022324 12. The method according to claims 1 or 9t, characterized in that »that the aqueous system 1 to 1000 mg / 1 Scaling agent added. 13. The method according to claims 1 or 9 »characterized» that the scale-removing smock is added after the scale has become tolerable Exceeded the limit. 14. The method according to claims 1 or 9 »characterized in that the scale removing agent an aqueous system without scale inhibitor or with at least one scale inhibitor »consisting from an acrylic acid polymer, a maleic acid polymer, an amide polymer, a phosphoric acid e-compound, a phosphonic acid compound or one for the formation of polyvalent metal ions (in water) capable polyvalent metal salt added. 15. The method according to claims 1 or 9 »characterized in that the scale removing agent adds at suitable intervals. 16. The method according to claim 15 »characterized» adding the scale removing agent once a month to once a year. 17. The method according to claims 1 to 9 »characterized» that the scale removing agent can be used clogs the aqueous system prior to (the necessary) periodic repair work. 18. The method according to claims 1 or 9 »characterized» that the scale is removed without stopping the system. 030064/0709 19. The method according to claims 1 or 9 »characterized» that the aqueous system is a boiler water system "a closed cooling water system" a salj water evaporation system to a waste water concentrate ion system or an aqueous system for the collection of exhaust dust. 20. The method according to claims 1 or 9 »characterized) that it is primarily around the scale
Calcium carbonate Iron oxide »Calcium silicate» Magnesium silicate and / or hydroxyapatite. 030064/0709