Cleaning agent for plate heat exchanger

Abstract

The invention relates to a plate heat exchanger cleaning agent which comprises the following components in parts by mass: 5-40 parts of orthophosphoric acid, 3-12 parts of hydroxyethylidene diphosphonic acid, 0.2-1.5 parts of sodium alkyl benzene sulfonate, 0.2-1.5 parts of sodium dodecyl benzene sulfonate, 0.1-1 part of OP-10 emulsifier, 1-5 parts of corrosion inhibitor and the balance of water, and the sum of the mass ratios of all the components is 100. The cleaning agent can quickly decompose easily-soluble scale in the scale, so that the scale is loosened and falls off, rust removal and scale removal cleaning are quickly completed, the cleaned stainless steel heat exchanger is bright as new, and meanwhile, the cleaning agent is weakly acidic, free of pungent smell, non-toxic, non-flammable, non-explosive and pollution-free to the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and particularly to a cleaning agent for plate heat exchangers. Background Art

[0002] At present, condensers and plate heat exchangers have been widely adopted by heating enterprises. However, scaling, corrosion, and biological slime may occur in their water circulation systems. In severe cases, it will affect the normal operation of the system, increase the operation cost, shorten the normal service life of the equipment, and lead to early scrapping of the equipment. The reasons for these failures include but are not limited to: 1. The water used in the system generally adopts tap water containing a large amount of scaling ions such as Ca2 + , Mg2 + etc. These scaling ions are extremely likely to precipitate from the water saturated when the water temperature rises or evaporates and concentrates, and deposit on the metal surface in the heat exchanger and pipe network to form scale; 2. After some sediment and various algal and microbial organisms enter the water system, due to the suitable temperature for the growth and reproduction of microorganisms, a large amount of microbial slime is generated in the system, which adheres to the inside of the heat exchanger tube and mixes with the scale to form biological scale; 3. Dissolved oxygen and salts in the water will cause oxygen corrosion and chemical corrosion to the metal materials of the heating system. Since the system is composed of multiple materials, in water containing a large amount of electrolyte salts, electric couples and corrosion cells are formed between different metals, thus causing electrochemical corrosion to the metals in the system. Scaling and biological slime will also cause under-deposit corrosion and microbial corrosion to the metal.

[0003] So far, after scaling in heating systems at home and abroad, strongly corrosive pickling has been used to remove scale. Strong acid cleaning is very harmful to heating equipment, and it corrodes metals, shortens the service life of the equipment, and leads to early scrapping of the equipment. At the same time, the cleaning efficiency is low and the scale removal is not thorough. Pickling can only wash out the carbonate scale in the heating system, but cannot dissolve the sulfate and siliceous scale. Therefore, a large amount of insoluble scale will remain in the system after cleaning, the cleaning rate of heating equipment is low, and it is difficult to effectively restore the heat transfer efficiency of the heat exchanger and the heating efficiency in winter after cleaning. Summary of the Invention

[0004] The object of the present invention is to provide a cleaning agent for plate heat exchangers, which solves the problem that electric couples are formed among them due to the electrode potential difference in the pickling solution, resulting in galvanic corrosion and intergranular damage to the heat exchanger.

[0005] To achieve the above object, the technical solution protected by the present invention is: a cleaning agent for plate heat exchangers, and its technical key points are: the mass ratio range of each component of the cleaning agent is: orthophosphoric acid 5 - 40, hydroxyethylidene diphosphonic acid 3 - 12, alkyl benzene sulfonic acid 0.2 - 1.5, sodium dodecyl benzene sulfonate 0.2 - 1.5, OP-10 emulsifier 0.1 - 1, corrosion inhibitor 1 - 5, and water is added to 100.

[0006] Preferably, the mass ratio of each component is as follows: orthophosphoric acid 12, hydroxyethylidene diphosphonic acid 4, alkyl benzene sulfonate 1.5, dodecyl benzene sulfonate 1.5, OP-10 emulsifier 1, corrosion inhibitor 1, and water 100.

[0007] Preferably, the preparation method of the plate heat exchanger cleaning agent is as follows:

[0008] S1: Add water into the reaction tank, and then sequentially add orthophosphoric acid with a mass ratio of 12, hydroxyethylidene diphosphonic acid with a mass ratio of 4, alkyl benzene sulfonate with a mass ratio of 1.5, dodecyl benzene sulfonate with a mass ratio of 1.5, OP-10 emulsifier with a mass ratio of 1, and corrosion inhibitor with a mass ratio of 1 into the reaction tank to obtain a mixed solution.

[0009] S2: Stir the mixed solution obtained in S1 for 15 minutes. After all components are completely dissolved, the preparation of the plate heat exchanger cleaning agent is completed.

[0010] The advantages and beneficial effects of the present invention are as follows: The plate heat exchanger cleaning agent protected by the present invention can be applicable to the cleaning and descaling of important equipment such as stainless steel materials, pipelines, and containers. After cleaning, it has no erosive effect on the surface of stainless steel. At the same time, it is less affected by acid-base, hard and soft water, and seawater, has strong decontamination ability and good cleaning effect. It also has the characteristics of simple and convenient use, high descaling rate, no corrosion, and non-toxicity. The heat exchanger plates after cleaning are brand new, can be recycled and reused, reduce pollution, and lower the cleaning cost.

[0011] The present invention is a degradable and highly efficient environmental protection cleaning product, mainly used for removing the most stubborn calcium and magnesium carbonate salts, sulfate scale, and rust precipitates generated in water-using equipment. It is safe, non-toxic, non-flammable, pollution-free, non-corrosive, and degradable. It not only has no harm to people, equipment, and the environment, but also automatically identifies different metal materials after entering the system. While dissolving, decomposing, penetrating, and peeling off the scale, it protects different metals, such as carbon steel, copper, stainless steel, glass, plastic, rubber, ceramic, aluminum, and aluminum alloy, etc. The heat exchanger cleaning agent has the following advantages:

[0012] 1. Safe and environmentally friendly: The heat exchanger cleaning agent is non-toxic, harmless, non-corrosive, and degradable, and can be directly in contact with the human skin without causing significant impact.

[0013] 2. Fast and effective: Special wetting agents, penetrants, and dispersants in the heat exchanger cleaning agent formula can effectively decompose complex scale in the sediment and directly clean it to the original metal surface of the equipment. At the same time, the special corrosion inhibitor complex in the product after cleaning can form a pre-film layer on the metal surface, which can not only protect the metal material from medium corrosion but also delay the secondary formation of scale. Usually, the equipment can be cleaned within 2 - 4 hours.

[0014] 3. Simple operation: The heat exchanger cleaning agent product is easy to operate and can be achieved without special tools and professionally trained personnel. Its cleaning process can consider methods such as circulation and soaking according to the actual situation. TLXS-2 can be diluted with water in proportion according to the scale situation in the equipment.

[0015] 4. Low cost: The special penetration and dispersion functions of this product can loosen the scale, and through wiping, flushing, circulation, etc., these scales can be easily peeled off from the metal surface, thus shortening the cleaning time and reducing the dosage of the cleaning agent. Therefore, the benefits brought by the rapidity, thoroughness, non-corrosiveness, safety, environmental protection, biodegradability, and reusability of TLXS-2 heat exchanger cleaning agent to users are very obvious.

[0016] 6. Wide application: The heat exchanger cleaning agent can be widely applied to industrial manufacturing enterprises, marine industries and transportation, commercial central air conditioners and automobile water tanks, household water heaters, and various condensers, exchangers, compressors, vacuum pumps, cooking vessels, air-cooled machines, chemical scrubbers, filters, etc. Specific implementation manners

[0017] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0018] Embodiment 1:

[0019] The mass ratio of each component of the cleaning agent is: orthophosphoric acid 12, hydroxyethylidene diphosphonic acid 4, alkyl benzene sulfonate 1.5, dodecyl benzene sulfonate 1.5, OP-10 emulsifier 1, corrosion inhibitor 1, water 100.

[0020] Its preparation method is as follows:

[0021] S1: Add water with a mass ratio of 100 into the reaction tank, and then successively add orthophosphoric acid with a mass ratio of 12, hydroxyethylidene diphosphonic acid with a mass ratio of 4, alkyl benzene sulfonate with a mass ratio of 1.5, dodecyl benzene sulfonate with a mass ratio of 1.5, OP-10 emulsifier with a mass ratio of 1, and corrosion inhibitor with a mass ratio of 1 into the reaction tank to obtain a mixed solution;

[0022] S2: Stir the mixed solution obtained in S1 for 15 minutes. After all components are completely dissolved, the preparation of the plate heat exchanger cleaning agent is completed.

[0023] In the above embodiments, a reasonable mass ratio is applied, so that the obtained plate heat exchanger cleaning agent can quickly remove and dissolve scale, rust and other deposits in various heat exchange devices.

[0024] Embodiment Two:

[0025] The mass ratio of each component of the cleaning agent is as follows: orthophosphoric acid 5, hydroxyethylethylenediphosphonic acid 3, alkylbenzene sulfonic acid 0.5, sodium dodecylbenzene sulfonate 0.5, OP-10 emulsifier 0.6, corrosion inhibitor 1, and water is added to 100.

[0026] The preparation method of the plate heat exchanger cleaning agent is the same as that in Embodiment One.

[0027] In the above embodiments, the mass fractions of each substance are changed. The present invention can form a protective film on the metal surface while removing scale, preventing metal corrosion and the rapid formation of scale.

[0028] Embodiment Three:

[0029] The mass ratio of each component of the cleaning agent is as follows: orthophosphoric acid 20, hydroxyethylethylenediphosphonic acid 6, alkylbenzene sulfonic acid 0.8, sodium dodecylbenzene sulfonate 0.8, OP-10 emulsifier 0.6, corrosion inhibitor 2, and water is added to 100.

[0030] In the above embodiments, by changing the mass fractions of each substance, the surface of the product has a gloss and does not turn dull after cleaning, and has no erosive effect on the surface of stainless steel.

[0031] In the prior art, the applicant wants to emphasize that the scaling and corrosion of heat exchangers are relatively common phenomena, and their harms include but are not limited to the following points:

[0032] First, it will cause a significant increase in energy consumption and an increase in operating costs; after scale and biological slime are formed in the system, the heat transfer efficiency of the heat exchanger decreases, the circulation area of the circulating water becomes smaller, and the circulation resistance increases, thereby resulting in a significant increase in energy consumption and an increase in costs.

[0033] Second, it will cause the system working efficiency to decline and affect heating: after the system is scaled, the efficiency of the heat exchanger decreases, the hot water outlet temperature decreases, the return water temperature increases, and the temperature difference between the inlet and outlet water decreases. As a result, the heating efficiency in winter decreases and the room temperature decreases.

[0034] Thirdly, it is easy to shorten the service life of the equipment and increase the equipment maintenance cost: Scaling and slime faults affect the normal operation of the system, and periodic cleaning and maintenance are required, thus greatly increasing the maintenance and cleaning costs of the equipment. Such costs are much higher than the usual maintenance costs. Due to corrosion, the metal materials of the heating water system are damaged, and this damage will shorten the service life of equipment such as heat exchangers and pipelines.

[0035] In this application, the plate heat exchanger cleaning agent protected by this application is a cleaning agent for TLXS-2 plate heat exchangers, which is composed of components such as organic chelating agents, promoters, surfactants and inorganic auxiliaries. Using such an original all-organic chelating cleaning technology, the cleaning agent is weakly acidic, has no pungent smell, is non-toxic, is not flammable or explosive, has no pollution to the environment, is simple to operate, and saves labor and time. At the same time, the cleaning agent can quickly decompose the easily soluble scale in the scale, make the scale loose and fall off, quickly complete rust removal and scale removal cleaning, and the stainless steel heat exchanger after cleaning is as bright as new.

[0036] Plate heat exchangers exchange heat through thin rectangular channels formed between various plates. Long-term operation will cause the flow channels of the heat exchanger to be blocked by scale and adhesives, resulting in a decrease in the heat transfer efficiency of the heat exchanger, a shortening of the heat transfer cycle, an increase in energy consumption, and affecting the normal operation of the heat exchanger. Since the scale on the plates is firmly combined with the heat transfer plates and it is difficult to remove it by physical methods, the acid cleaning method in chemical cleaning is selected to remove scale. Some problems that occur in the traditional acid-based chemical cleaning of plates not only cannot completely remove deposits such as scale, but also cause corrosion to the stainless steel plates. When neutralization is not good, the residual acid will cause secondary corrosion or under-scale corrosion to the material, shortening the service life of the plates. Moreover, the cleaning waste liquid cannot be directly discharged, and a certain amount of funds need to be invested in wastewater treatment. Therefore, whether it is possible to find a highly efficient, environmentally friendly and safe chemical cleaning agent that not only has good cleaning effect but also has no corrosion to the equipment is the pursuit goal of every engineer for many years.

[0037] The selection of chemical cleaning agents is the most crucial issue in chemical cleaning. During chemical cleaning, the cleaning medium should be selected according to the metal material, structural characteristics, chemical composition of the deposits (scale), deposition state of the scale and the amount of scale of the equipment to be cleaned, and the process conditions of the selected medium should be determined to achieve the two purposes of removing deposits and protecting the equipment from corrosion.

[0038] In order to ensure that the chemical cleaning agent has both the purpose of removing deposits and protecting the equipment from corrosion, the selection principles are as follows:

[0039] First of all, the cleaning agent must be easy to chemically react with the deposits to be cleaned, and a sufficient reaction rate is required during the reaction. The reaction products must be easily soluble in water and have good chemical stability.

[0040] Secondly, when the cleaning agent comes into contact with metal materials, it shall not cause changes in various properties of the metal materials. For example, stainless steel materials cannot be cleaned with hydrochloric acid cleaning media, otherwise there will inevitably be a risk of stress corrosion cracking of stainless steel.

[0041] At the same time, the cleaning agent must have a good coordination effect with other agents such as corrosion inhibitors to ensure that the corrosion rate value of the metal during the cleaning process is within the range specified in the regulations.

[0042] Furthermore, the cleaning agent itself should have as weak a corrosiveness to metals as possible, so that the equipment has higher safety. The toxicity of the cleaning agent should be as small as possible to facilitate the discharge and treatment of cleaning waste liquid.

[0043] Moreover, the price of the cleaning agent should be as economical as possible to help reduce the cleaning cost. The application process of the cleaning agent is simple and the capital investment is small.

[0044] At present, condensers and plate heat exchangers have been widely adopted by heating enterprises. However, the problems of fuel waste, equipment damage, reduced heating efficiency, and increased heating costs caused by scaling in condensers and plate stainless steel heat exchangers have become a major concern for enterprises. In view of the actual situation that condensers and plate heat exchangers are made of precious materials, have high construction costs, are difficult to clean, and are prone to corrosion and leakage, the TLXS-2 plate heat exchanger cleaning agent independently developed in this application has the characteristics of convenient use, high scale removal rate, no corrosion, and non-toxicity. After cleaning, the heat exchanger plates are brand new.

[0045] The pickling technology dissolves the dirt in the heating system by means of strongly corrosive acids. Since the heating water system is a multi-material system, acids not only have strong chemical corrosion on metals, but also different metals form galvanic couples with each other due to the electrode potential difference in the acid cleaning solution, resulting in galvanic corrosion and intergranular damage of the heat exchanger, thus greatly shortening the service life of the heating equipment. Since the metal wall of the heat exchanger is very thin, the strongly corrosive acid cleaning solution is easy to corrode and perforate it. When the damage is serious, the equipment to be cleaned can be scrapped in advance. In recent years, cleaning accidents have occurred frequently in China where expensive heat exchanger equipment has been scrapped immediately after pickling due to improper pickling.

[0046] The pickling technology can only remove carbonate scale in the heating system and cannot dissolve sulfate and siliceous dirt. Therefore, a large amount of insoluble scale remains in the system after cleaning, the cleaning rate of the heating equipment is low, and it is difficult to effectively restore the heat transfer efficiency of the heat exchanger and the winter heating efficiency after cleaning.

[0047] In the prior art, fouling, microbial slime, and the associated corrosion failures have a great impact on the safe, normal, and low-cost operation of the system. Chemical cleaning needs to be carried out regularly. Through safe and effective chemical cleaning, the following purposes can be achieved: First, it can thoroughly clean various water scale, microbial slime, and corrosion products in the water system, ensure the safe and normal operation of the system, and significantly improve the heating efficiency. Second, it can reduce the operating cost, save a large amount of energy, and after descaling, the coal consumption or (gas) consumption of the system can be reduced by 20 - 30%. Finally, it can achieve the effect of protecting metals, eliminate corrosion hazards, and extend the service life of heat exchangers and pipeline equipment.

[0048] In summary, the present invention can quickly remove and dissolve water scale, rust scale, and other deposits in various heat exchange devices. At the same time, this product is less affected by acids and alkalis, hard and soft water, and seawater, has strong decontamination ability, good cleaning effect, is not flammable, and the cleaning agent is simple and convenient to use, with high descaling rate, no corrosion, and non-toxic characteristics. After cleaning, the heat exchanger plates are brand new, and it can also be recycled and reused, reducing pollution and lowering the cleaning cost.

[0049] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention.

[0050] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A plate heat exchanger cleaning agent, characterized in that: The mass ratio range of each component of the cleaning agent is as follows: orthophosphoric acid 5 - 40, hydroxyethylidene diphosphonic acid 3 - 12, alkyl benzene sulfonate 0.2 - 1.5, dodecyl benzene sulfonate 0.2 - 1.5, OP-10 emulsifier 0.1 - 1, corrosion inhibitor 1 - 5, water added to 100.

2. The plate heat exchanger cleaning agent according to claim 1, characterized in that: The mass ratio of each component is: orthophosphoric acid 12, hydroxyethylidene diphosphonic acid 4, alkyl benzene sulfonate 1.5, dodecyl benzene sulfonate 1.5, OP-10 emulsifier 1, corrosion inhibitor 1, water 100.

3. A preparation method of the plate heat exchanger cleaning agent according to any one of claims 1 - 2, characterized in that: The specific steps are as follows: S1: Add water into the reaction tank, and then sequentially add orthophosphoric acid with a mass ratio of 12, hydroxyethylidene diphosphonic acid with a mass ratio of 4, alkyl benzene sulfonate with a mass ratio of 1.5, dodecyl benzene sulfonate with a mass ratio of 1.5, OP-10 emulsifier with a mass ratio of 1, and corrosion inhibitor with a mass ratio of 1 into the reaction tank to obtain a mixed solution; S2: Stir the mixed solution obtained in S1 for 15 min. After all components are completely dissolved, the preparation of the plate heat exchanger cleaning agent is completed.