I. Preface

As an important symbol of the modern construction industry, more and more high-rise buildings are dotted with large and medium-sized cities lined up in the building complex. In order to create a comfortable working and living environment in medium and high-rise buildings, centralized air-conditioning technology is widely used. With the rapid increase in the proportion of high-rise buildings in modern urban buildings, the use of central air-conditioning units have also been rapidly popularized.

Central air conditioning is a high input and high efficiency equipment, the overall structure of the multi-metal, effect performance is very sensitive device. Usually the air conditioning unit cooling water device using open cooling mode, cold water system using closed circulation. Due to the cooling water evaporation and concentration and a large number of bacterial and algal reproduction, the system is easy to produce scale and biological slime, especially the host condenser, evaporator part, very easy to scale failure, resulting in a decline in heat transfer efficiency, cooling water, cold water import and export temperature increases, exhaust pressure rises, a substantial increase in power consumption, so that the air conditioning system efficiency declines, the operating costs rise. Therefore, in order to make the central air conditioning system to maintain a normal and efficient working condition, it is necessary to regularly clean and descale the air conditioning cooling water system. Northern regions due to winter heating, cooling water system will also be scaled, also need to clean and descale, restore the system heat exchange performance.

To date, the central air conditioning cleaning are used acid cleaning method, the use of inorganic strong acid descaling process exists on the air conditioning system, especially the host part of the corrosion damage, cleaning waste liquid toxic, emission pollution of the environment and other drawbacks, in particular, acid cleaning in addition to the air conditioning system of the metal produces a very strong chemical corrosion, on the host condenser, evaporator and fan coils of the copper tube will produce a serious selective Intercrystalline corrosion, the metal surface activated by the acid is also prone to many types of corrosion damage in subsequent operation, shortening the service life of the equipment and leading to early retirement of the host.

In order to solve the problem of corrosion and toxic contamination of the air conditioning system of the acid cleaning technology, scientists and technologists began to study the non-corrosive, non-corrosive, non-polluting chemical cleaning technology, Qufu Tianlan Cleaning Services Co., Ltd. after a few years of scientific and technological research, the successful launch of a completely non-acid, non-corrosive, automatic descaling net series of central air-conditioning cleaner, maintenance agent, from the laboratory trial to the application of actual air-conditioning units Obtained a lot of data to prove that the central air-conditioning cleaner completely solved the acid cleaning method of corrosion of metals and toxic waste discharge serious pollution of the environment, technical products since the introduction of tens of thousands of domestic units using automatic descaling net series of central air-conditioning system cleaning and descaling, water quality treatment, have achieved good results, well received by the user welcome.

At the same time the automatic descaling net series cleaner, can be cleaned and descaled in the operation of the equipment, solving the problem of downtime cleaning.

Second, automatic descaling net cleaning principle

According to the ligand field theory, the D orbitals of metal ions can be split under the influence of electrostatic field of some ligand compounds to form orbitals with different energies, when the ligand gives the lone pair of electrons with the center of the metal element to form σ-bonds, if there is an empty π molecular orbitals or an empty p-d molecular orbitals in the molecules of the ligand, and symmetry is appropriate, the lone pair on the d orbit of the center element is not a good choice. The lone pair of electrons in the d-orbital of the central element can form a feedback π-bond with the ligand, thus forming a stable coordination compound.

Based on the above principles, the use of "GR-943B" can make Ca2+, Mg2+ d orbitals to split the energy level, and compounds with π molecular orbitals as the π-accepting ligand, when these compounds and calcium (magnesium) salts, can be formed with Ca2+, Mg2 + stable coordination compounds, thus destroying the molecular structure of the scaling compounds. This destroys the molecular structure of the scaling compound and removes it by dissolution.

For the biological sludge in the dirt, the biological inactivation component in the automatic descaling net reacts with it to eliminate or reduce the viscosity. The inactivated sludge can be easily detached from the scale layer or metal surface, dispersed and dissolved in water and removed.

Three, the central air-conditioning system common operational faults and causes

Central air-conditioning due to the daily operation of its water system often scaling, corrosion and biological sludge, etc., serious impact on the normal operation of the central air-conditioning system, increase operating costs, shorten the normal service life of the equipment, leading to early retirement of the equipment. These failures are mainly caused by the following reasons:

1, air-conditioning system water are generally used untreated tap water containing a large number of Ca2 +, Mg2 + and other scale ions, these scale ions in the water temperature or evaporation of the concentration of the water is very easy to saturate precipitation from the water deposited in the condenser, the evaporator tube metal surfaces and the formation of scale.

2, most of the cooling water system to take the open cooling, the atmosphere of the sediment and a variety of bacteria and algae microorganisms can enter the cooling water system through the cooling tower, and the cooling water temperature is very suitable for microbial growth and reproduction, so that the system will inevitably produce a large number of bacteria and algae. Bacteria and algae are very easy to form microbial slime, attached to the cooling tower filler and host heat exchanger tube, mixed with scale to form biological dirt.

3, dissolved oxygen and salts in the water on the air-conditioning system of metal materials produce oxygen corrosion and chemical corrosion. As the central air conditioning system is composed of a variety of materials, in the water containing a large number of electrolyte salts, different metals between the formation of galvanic coupling and corrosion battery, thus generating galvanic corrosion of the system metal. Scaling and biological slime can also lead to metal to produce sub-scale corrosion and microbial corrosion.

4. A customary understanding is that the raw water after softening, the pH value of the water increased, and thus the corrosiveness of the water is also reduced. In fact, the boiler steel in the raw water and softened water corrosion rate are very large, according to the boiler corrosion standards, all belong to the accidental corrosion level. Moreover, softened water is more corrosive than raw water. Raw water contains natural corrosion inhibitor calcium bicarbonate, which is an anodic corrosion inhibitor, when the steel surface with the cathodic reaction product of hydroxide ions meet, that is, the generation of calcium carbonate precipitation and cover the cathodic surface. As the cathodic process is inhibited, the corrosion rate of steel is reduced. When the raw water is softened, with the hardness component is removed, the original natural corrosion inhibitor in the water does not exist, and thus the corrosive properties of water increased. At the same time, the corrosion products cover the metal surface and become a scale situation has become serious. Therefore, the use of softened water system, it is more necessary to take anti-corrosion measures.

Four, scaling and corrosion hazards

1, a substantial increase in energy consumption, operating costs: air-conditioning system scaling and biological slime, so that the host condenser and evaporator heat transfer efficiency decreased, the circulating water circulation area becomes smaller, the circulation resistance increases, cooling water and chilled water inlet and outlet temperatures rise, the exhaust pressure increases, leading to a substantial increase in energy consumption, so that operating costs Increase.

2, the system efficiency decline, affecting cooling and heating: air conditioning system scaling will cause the host to work less efficiently, chilled water outlet temperature rises, affecting the normal supply of cold air. When the scaling and slime failure is serious, it will lead to the host high pressure protection and interruption of operation. Fan cooling pipe scaling will also make the winter heating efficiency decline, the room temperature is low.

3, shorten the service life of the equipment, increase the cost of equipment maintenance: scaling and slime failure affects the normal operation of the system, the need for periodic cleaning and overhaul, thus substantially increasing the cost of overhauling and cleaning equipment. This cost is much higher than the normal maintenance costs of the system. Due to corrosion, so that the air-conditioning water system metal material damage, this damage will shorten the service life of the equipment and piping, resulting in air-conditioning water piping and end equipment festering leakage, direct damage to the room decorative materials, increased maintenance and decorating costs, and in severe cases lead to the host system scrapped in advance.

Fifth, the central air conditioning cleaning market technology status

To date, the domestic and foreign central air conditioning water system scaling are used after strong corrosive acid cleaning descaling, strong acidic cleaning of air conditioning system is very harmful;

1, corrosion of metal, damage to the host, shorten the service life of the air conditioning, resulting in the early retirement of the equipment; acid cleaning technology is a strong corrosive acid with the help of the central air conditioning system in the dirt dissolved. Dirt in the system. As the central air conditioning water system is a multi-material system, acid has a strong chemical corrosion of metal, thus making the central air conditioning system life greatly shortened. The reasons are as follows:

(1) acid (such as hydrochloric acid) itself can be with the main materials of the equipment (such as steel, copper) chemical reaction, so that the steel, copper in the form of ions dissolved in the water, corrosion of the metal, even if the addition of corrosion inhibitors, can not be completed to prevent the reaction from occurring, the equipment will still cause harm. If the cleaning time is prolonged, produce a large number of oxidizing Fe3 + ions, the equipment will cause greater corrosion.

(2) After adding the acid, the acid itself can be ionized in the water, producing a large number of anions and cations, greatly increasing the conductivity of the aqueous solution, accelerating the microelectrochemical reaction, accelerating the corrosion of the equipment.

(3) in the cleaning, equipment (mainly heat exchanger expansion tube) is prone to the following four kinds of hazardous corrosion: interstitial corrosion, pitting, galvanic corrosion, intergranular corrosion. Which in the copper tube and steel plate expansion, in the manufacture of equipment itself there is a small size gap (on both sides of the expansion), it is very easy to cause interstitial corrosion. In the copper tube protrusion, the general scale is thicker, easy to cause corrosion under the scale (due to the role of the concentration of the battery), after adding a large number of C1-ions, due to the C1- has a more prominent accelerated pitting effect, there is a possibility of localized pitting corrosion of the equipment perforation. In the expansion joint, due to the equipment itself is a dissimilar metal (steel, copper) contact, there is a potential difference (steel potential is higher than copper), the solution conductivity increases, will accelerate the galvanic coupling corrosion. Finally C1 - has a clear role in accelerating intergranular corrosion, due to the intergranular geometry is extremely small (a few microns), corrosion occurs, the naked eye is not easy to find, which is more dangerous for stainless steel heat exchanger, it is likely to appear on the surface of the stainless steel has not seen corrosion, but due to intergranular corrosion, has made the stainless steel plate etched through the phenomenon.

(4)Copper tube and steel plate generally take the expansion joint, embedded amount of only a few silk (a few millimeters), easier to corrosion perforation.

(5) Once corrosion, causing leakage, water will enter the Freon: Freon meets water (even if it is water in the air), the reaction occurs, generating HCI (hydrochloric acid), HF (hydrofluoric acid), hydrochloric acid is a strong acid, corrosive, hydrofluoric acid corrosive, corrosive, general metal can be quickly corroded (including general stainless steel, only high chromium-nickel molybdenum stainless steel, with the exception of). Once the corrosion perforation (even pinhole), generating HCI, HF, the two acids will in turn corrode the perforation, increasing the hole diameter, increasing the amount of water leakage, generating more HCI, HF, resulting in a vicious cycle. For lithium bromide units, the requirements of the higher airtight, lithium bromide with water or air will greatly increase its corrosiveness, resulting in serious corrosion of the unit, or even scrapped.

(6) because of trace leakage will cause a vicious circle, and tiny leakage in the pressure airtightness test is more difficult to find (cleaning is generally not done after the airtightness test), to do the vacuum test, the vacuum drop is not obvious, it is also difficult to find.

Central air conditioning host condenser, evaporator tube wall is very thin, strong corrosive acid cleaning solution is easy to corrode its perforation, damage is serious, can make the host then scrap. In recent years, there have been a number of domestic due to improper pickling led to the value of nearly ten million dollars of central air conditioning system washed that is scrapped cleaning accident. In summary, due to the central air conditioning equipment and refrigerant specificity, should not use traditional cleaning technology.

2, damage to indoor decoration materials, increase equipment maintenance costs; due to pickling is very easy to cause metal corrosion damage to the central air conditioning system, even if it is mild damage, many times after pickling air conditioning system after running for a period of time, but also due to corrosion damage and frequent maintenance and replacement of damaged parts, thus greatly increasing the system maintenance costs. More problematic is that, hotels, hotels, high-grade office buildings of the central air conditioning system, if the pickling is not appropriate will cause corrosion of the pipeline leakage, leakage of the pickling solution will damage the interior decoration, maintenance of the leaking pipeline or replacement of damaged parts will lead to the redecoration of the indoor environment, and its direct consequence is that air conditioning users not only have to pay for the damage to the part of the equipment repair and replacement costs, but also have to pay for the indoor redecoration of the cost of more! , affecting normal business and office. These costs and losses are sometimes often several times or even more than ten times the amount of the acid washing project.

3, low cleaning efficiency, scale removal is not complete; pickling can only remove carbonate scale in the central air-conditioning system, sulfate and siliceous dirt can not be dissolved, so after cleaning the system remains a large number of insoluble scale, air conditioning equipment, cleaning rate is low, cleaning, it is difficult to effectively restore the central air-conditioning cooling efficiency and winter heating efficiency.

4, generally need to stop the cleaning, and need to change its operating parameters.

5, the drainage can not meet the national environmental requirements, poisonous organisms, pollution of the environment; pickling solution contains a large number of highly toxic and corrosive chemicals, COD, BOD value exceeds the national environmental protection indicators hundreds or even thousands of times, the waste liquid on the flowers, plants and aquatic organisms have a strong toxicity and harm. Currently around the cleaning companies and water treatment companies to reduce engineering costs, pickling waste liquid are not treated and directly discharged, thus causing great damage and harm to the ecological environment.

Sixth, the central air-conditioning chemical cleaning technology development trend

In view of the strong corrosive pickling technology on the central air-conditioning equipment and the ecological environment of the high polluting, domestic and foreign countries are actively researching and developing safe, non-polluting cleaning technology. Due to the water treatment and chemical cleaning of the central air conditioning system safety, normal operation has a great impact, in recent years, improper pickling caused by ten million dollars worth of central air conditioning system serious corrosion or even scrapped pickling accidents occur from time to time. Therefore, some domestic provinces and regions of the technical regulatory agencies have begun to central air-conditioning cleaning to implement strict cleaning safety supervision. The State Environmental Protection Administration has also listed the acid washing technology as one of the nine major sources of pollution, will be restricted and governance. Some areas of the country has been strictly prohibited acid washing central air conditioning and other heat exchange equipment.

With the national environmental protection legislation and law enforcement efforts to increase the use of efficient, safe, non-polluting chemical cleaning technology to replace the current use of acid cleaning technology will become the inevitable trend of the development of central air conditioning cleaning technology. Neutral acid-free cleaning technology successfully applied in the field of central air-conditioning cleaning, is undoubtedly a twenty-first century central air-conditioning chemical cleaning and water treatment technology development must be the way.

Seven, the purpose of chemical cleaning of central air conditioning

Scaling and microbial slime and the resulting corrosion failures, the system's safe, normal and low-cost operation of the great impact of the need to regularly carry out chemical cleaning, safe and effective chemical cleaning can be achieved for the following purposes:

1, the complete removal of cooling water and chilled water system within the scale, microbial slime and corrosion products, to ensure the safe and normal operation of the system, and to ensure the safe and normal operation of the system, and to ensure the safe and normal operation of the system. Corrosion products, to ensure the safe and normal operation of the system, significantly improve the cooling efficiency and heating efficiency;

2, reduce operating costs, substantial energy savings, cleaning can make the system power consumption or oil (gas) consumption reduced by 20-30%;

3, to protect the metal and the tower filler, to eliminate corrosion hazards, prolong the service life of equipment.

Eight, the central air-conditioning chemical maintenance purposes

As the central air-conditioning water system operation is prone to corrosion, scaling and slime failure, in order to ensure that the system is stable, efficient, safe and low-cost long-cycle operation, it is necessary to carry out effective routine maintenance of the water system. Maintenance can be achieved through the maintenance of the following purposes:

1, effective inhibition of bacterial and algal growth and reproduction, to prevent the production of a large number of biological slime, to prevent the rise of system resistance, to prevent the water system scaling;

2, to eliminate the dissolved oxygen in the water, microorganisms and other hazardous substances on the metal material corrosion of metals to protect the system from damage to a variety of materials, to extend the service life of equipment;

3, to ensure that the system process is normal, so that the equipment to maintain good heat transfer efficiency;

4, to reduce operating costs, substantial energy savings, good water quality can make the system power consumption or fuel consumption by 20-30%;

nine, GR-943 GREE neutral acid-free cleaning technology features

In order to solve the acid washing central air conditioning system due to corrosive damage caused by leakage or even scrapped, as well as acid washing central air-conditioning system, the system will not be used. Leakage or even scrapped and pickling waste liquid serious pollution of the environment, Lanzhou Institute of Corrosion Inhibition Technology after many years of scientific and technological research, research success automatically eliminates the scale net acid-free, non-polluting chemical cleaning technology to fill the gaps in the domestic and foreign central air-conditioning and industrial equipment, neutral acid-free green cleaning technology, its products are non-corrosive, environmentally friendly and non-polluting and various components of the scale can be effectively removed the technical performance, a complete solution to the corrosion of equipment that has been plaguing the chemical cleaning industry for many years, and to solve the problem. To plague the chemical cleaning industry over the years, equipment corrosion problems, sulfate insoluble scale can not be cleaned problems and production equipment can not run cleaning and pickling waste liquid serious pollution of the environment and other interlocking problems, and completely realize the industrial chemical cleaning from the process to the results of the formation of a completely virtuous cycle. Acid-free and safe neutral cleaning technology with its excellent technical performance in the domestic industrial chemical cleaning industry has created a series of records, through the national expert technical appraisal of acid-free and safe neutral chemical cleaning technology, authorized by the State Administration of Quality Supervision and Inspection of the Chinese Boiler Water Treatment Association registered and certified by the acid-free and safe neutral chemical cleaning technology, by the State Bureau of Technical Supervision review of the record of the acid-free and safe neutral chemical cleaning technology, by the National Water Association commissioned by the National Technical Supervision Bureau of the boiler pressure equipment owned by the competent institutions - pot inspection, special inspection of its descaling, anti-scaling and anti-corrosion performance of the running test proved that it is a truly efficient acid-free safety neutral chemical cleaning technology products. Compared with the current use of acidic technology, with automatic descaling net acid-free cleaning technology central air conditioning has the following technical characteristics:

1, neutral non-corrosive, safe and reliable. Descaling process cleaning solution pH value to remain neutral, corrosion rate of 0.1g/m2-h, lower than the corrosion rate of neutral water on metal, cleaning process of equipment metal without any corrosion damage, will not cause damage to the system leakage and shorten the service life of air-conditioning equipment, cleaning can be formed on the surface of the metal anticorrosive properties of the protective film, to ensure that the central air-conditioning system cleaning safety, normal and high-quality operation.

2, green and non-polluting, does not hurt the flowers and plants. Identified by the health department neutral cleaning agent is non-toxic, cleaning waste liquid without treatment that can meet national emission standards, waste liquid on the human body, flowers and plants without any impact on the environment is not polluting, is a green environmental protection products, the real realization of the central air conditioning and industrial equipment, green cleaning.

3, high cleaning efficiency, thorough descaling. Can effectively clean all types of scale and algae microbial slime, especially for acid washing technology can not remove sulfate, silica compounds and other insoluble dirt can also be thoroughly cleaned, descaling rate of 95% or more, after cleaning can effectively restore and improve the cooling and heating efficiency of the central air conditioning system.

4, no downtime, can be in the central air conditioning and other heat exchange equipment under normal operating conditions, thoroughly remove all kinds of dirt in the water system, does not affect the production and use.

5, anti-scaling and anti-corrosion. Add a small amount of neutral in the daily operation of the equipment, can prevent the equipment water system scaling and corrosion.

6, good economic performance, GR943 cleaning costs only "EDTA" method of 1/2 ~ 1/10. excellent cost performance.

7, energy-saving effect is remarkable, reduce operating costs. After the use of this technology, cleaning, central air conditioning power consumption (fluorine) or oil consumption (bromine) decreased significantly, saving electricity costs up to 30% or more. Due to the thorough descaling, cleaning process of no damage to the equipment, cleaning can ensure that the equipment is safe and effective, long cycle operation, so that the air-conditioning system maintenance costs and water treatment costs have dropped significantly, to the user to bring tangible economic benefits.

Ten, the central air-conditioning maintenance agent working principle

1, central air-conditioning cooling water operation maintenance agent, the maintenance agent selection can be combined with the metal ions in the water scaling ligand, and the water Ca2 +, Mg2 + metal ions chelating reaction, the formation of stable soluble chelates, which effectively prevents the water scaling deposits. The maintenance agent also contains bactericidal alga component, can effectively prevent the propagation of various bacteria and algae in the water and the production of biological slime, to maintain a clean system. Central air-conditioning cooling water operation and maintenance agent contains unique corrosion inhibition and anti-corrosion components, can effectively protect the system from damage to a variety of metals, to extend the service life of the equipment. Due to the above performance to ensure that the air conditioning cooling water system to maintain the best working condition, can significantly reduce power consumption and cleaning costs.

2, the central air-conditioning cooling water operation and maintenance agent is used for the daily operation and maintenance of the central air-conditioning chilled water system maintenance agent, the maintenance agent contains a variety of highly effective composite corrosion inhibitor, the system of steel, copper, stainless steel and other types of metal materials play a good role in protecting. The protective agent contains a unique deoxidizer, which can effectively remove dissolved oxygen in the water, eliminating the corrosion damage of dissolved oxygen on the equipment to avoid corrosion under the scale. Central air-conditioning cooling water operation and maintenance agent 2 contains metal ions that can inhibit the survival of microorganisms, which can reduce the corrosion of microorganisms on the equipment to ensure the safe operation of the equipment and extend the service life of the equipment.

Qufu Tianlan Cleaning Service Co., Ltd. developed a chelating green chemical cleaning agent - "automatic descaling net" series, to replace the current widespread use of acid cleaning technology. From now on, the boiler, central air conditioning and other heat exchange equipment chemical cleaning without acid, no corrosion, no stop and high descaling effect has become a reality.

Qufu Tianlan Cleaning Service Co., Ltd. specializes in boilers, central air-conditioning, silicon iron furnaces, smelting furnaces, cold storage