Classification and definition of industrial cleaning

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Definition and classification of 1. cleaning agent industry

(1) Cleaning agent industry definition

Industrial cleaning is the surface of the object by physical, chemical or biological action and the formation of the pollution layer or coating called dirt, remove these pollutants or coating and restore the original surface condition of the process called cleaning.
(2) Cleaning agent industry product classification

1) Classification according to the requirements of fineness

General industrial cleaning agent, precision industrial cleaning agent, ultra-precision industrial cleaning agent

General industrial cleaning agents, including vehicles, ships, aircraft surface cleaning, can only remove the relatively large dirt;
2. Precision industrial cleaning agents include cleaning in the processing of various products, cleaning of various materials and equipment surfaces, etc., characterized by the ability to remove tiny dirt particles;
Ultra-precision industrial fine lotion includes ultra-precision cleaning of mechanical parts, electronic components, optical components, etc. in the process of precision industrial production to eliminate extremely tiny dirt particles.
2) Classification of physical cleaning and chemical cleaning by cleaning method
1. Physical cleaning is the use of mechanics, acoustics, optics, electricity, thermal principles, relying on the role of external energy, such as mechanical friction, ultrasonic, negative pressure, high pressure, impact, ultraviolet light, steam, etc. to remove dirt on the surface of objects without changing the cleaning method of dirty components. That is, the method does not change the original chemical molecular composition.

① Mechanical cleaning method: sweeper and scraper cleaning method, drill pipe cleaning method, shot blasting cleaning method.

② Hydraulic cleaning method: low pressure hydraulic cleaning (the pressure of low pressure cleaning is 196-68 6千帕, about 2-7

Kilogram force/square centimeter, equal to 0.2-0.7Mpa).

③ high pressure hydraulic cleaning: high pressure cleaning pressure of 4900 kPa, about 50 kgf/square centimeter, equal to 5Mpa. This method is also called high pressure water jet method, high pressure cleaning machine.
Chemical cleaning is a method that relies on chemical reactions and uses chemicals or other solvents to remove dirt on the surface of objects. Such as the use of a variety of inorganic or organic acids to remove the surface of the object of rust, scale, with an oxidant to remove the surface of the object of color. The use of chemical agents to make the surface pollution or coating (such as scale layer) and chemical reaction to be removed, such as the scale layer of pickling, alkali washing, etc. In order to prevent the substrate from being corroded in chemical cleaning or to control the corrosion rate within the allowable range, the appropriate amount of corrosion inhibitor and additives for activation, penetration and wetting are usually added to the chemical cleaning solution. Methods: soaking method, circulation method, cleaning method in operation is also called non-stop chemical cleaning method.
3. Electronic cleaning method anti-scaling, descaling principle is: the use of high frequency electric field to change the molecular structure of water, so that the anti-scaling and descaling. When the water through the high-frequency electric field, its molecular physical structure has changed, the original association chain macromolecules, broken into a single water molecule, water salts of positive and negative ions are surrounded by a single water molecule, the movement speed is reduced, the number of effective collisions is reduced, the electrostatic attraction is reduced, can not be in the heated wall tube surface structure, so as to achieve the purpose of anti-scaling. At the same time, due to the increase of the dipole moment of water molecules, the positive and negative ions of salt (the absorption capacity of scale molecules increases, so that the scale on the heating surface or tube wall becomes soft and easy to fall off, resulting in the effect of descaling.
4. Electrostatic anti-scaling, descaling and electronic descaling, but also by changing the state of water molecules to achieve anti-scaling, descaling purposes. Only the latter is the use of electrostatic field, rather than the role of electrons. The mechanism is that water molecules have polarity (also known as dipoles), and when a water dipole passes through an electrostatic field, each water dipole will press positive and negative.

arranged in an orderly succession. If the water contains dissolved salts, its positive and negative ions will be surrounded by water dipoles, and they will also be arranged in the water dipole group in positive and negative order. They cannot move by themselves, so they cannot be close to the tube (device) wall, and then deposit on the tube (device) wall to form scale. At the same time, the oxygen released in the water can produce a very thin layer of oxide layer on the pipe wall, which can prevent the corrosion of the pipe (device) wall.
3) according to the cleaning medium classification of wet cleaning and dry cleaning
Generally, cleaning in a liquid medium is called wet cleaning, and most of the traditional cleaning methods are wet cleaning.
2. Cleaning in gas medium is called dry cleaning, such as laser cleaning, ultraviolet cleaning, plasma cleaning, dry ice cleaning, etc,
Corrosion inhibitor is in the corrosive medium, adding a small amount of a substance, can make the metal corrosion rate is greatly reduced, this substance is called corrosion inhibitor. This method of protecting metals is called the corrosion inhibitor protection law.
classification of corrosion inhibitors:

The mechanism of action is divided into: anode, cathode, mixed type. The characteristics of the protective film: oxidation type, adsorption type, precipitation type. Other classifications: ① organic and inorganic corrosion inhibitors ② liquid phase, gas phase and solid phase corrosion inhibitors ③ steel, copper and aluminum corrosion inhibitors ④ acidic, alkaline and neutral corrosion inhibitors.
4) Classification according to the state of cleaning objects

Cleaning before production, cleaning without stopping production and cleaning for maintenance

Cleaning before production: chemical cleaning and passivation treatment must be carried out before the new chemical equipment is put into production. It has been proved that chemical cleaning and passivation before start-up are of great significance to the safety and economic benefits of production. The economic benefits are enormous.

Purpose of cleaning and passivation before production

The raw materials of the equipment of the system, such as steel pipes, steel plates, stainless steel, etc., will form rolled skin during rolling; during the manufacturing, storage, transportation and installation of the equipment, rust, welding slag and oily rust inhibitor coated on the steel for corrosion protection will form, dust, Impurities such as sand, cement, and thermal insulation materials will also be mixed into the equipment. Due to the increase in equipment capacity from the steel pipe, steel plate factory, equipment manufacturing, storage and transportation, installation to the final production of the time required to become longer, the equipment of the weld increased, the heating surface increased, the above-mentioned rolling skin, rust, welding slag, rust inhibitor and sediment and other impurities of the total amount increased.
After cleaning, a dense layer of chemical passivation film is formed on the clean metal surface, which can effectively prevent the recurrence of dirt and effectively protect the equipment. Protect equipment from corrosion or other chemical damage
Non-stop cleaning: In the production process of chemical equipment, some equipment cannot be stopped for maintenance and cleaning. Therefore, the non-stop cleaning technology came into being. Domestic non-stop cleaning technology is relatively perfect, can be in the state of equipment operation for chemical cleaning and passivation technology. So as to ensure the safety and efficiency of the operation of the equipment.
3. Shutdown maintenance and cleaning: Shutdown maintenance is the cleaning operation in which all equipment is shut down for maintenance during the annual planned maintenance time of chemical enterprises. Relatively speaking, the shutdown maintenance is to carry out cyclic chemical cleaning or high-pressure water jet cleaning operation for a single equipment.
(3) product composition and decontamination mechanism dirt
Scale is a deposit on the surface (or interior) of a substrate that is undesirable and reduces the use function of the substrate or changes the clean image of the substrate.
Types of Dirt

(1) Classification according to the shape of dirt

① granular dirt such as solid particles, microbial particles.

Membrane dirt such as grease, polymer compounds or inorganic precipitates on the surface of the substrate to form a film-like material, the film can be solid, may also be semi-solid. Some dirt is between particles and films, and some are dispersed in the solvent in suspension.
(2) According to the classification of the chemical composition of the dirt, the dirt can be divided into two categories: inorganic and organic.
Inorganic dirt such as scale, rust, dirt, from the chemical composition, they belong to metal or non-metal oxides and hydrates or inorganic salts.
A, sulfate work with calcium sulfate, magnesium sulfate (CaSO4,MgSO4), because calcium sulfate is not dissolved in common commonly used acid, so can not be directly washed with acid (such as hydrochloric acid or nitric acid). However, the solubility product of calcium sulfate is greater than that of calcium carbonate, so in the presence of a sufficient amount of carbonate, the sulfate (e. g. calcium sulfate) can be converted into the corresponding carbonate, and then washed with hydrochloric acid, etc. Therefore, boilers containing a large amount of sulfate scale need to be boiled with alkali (sodium carbonate in lye) before pickling.
B. Carbonate is mainly calcium carbonate and magnesium carbonate (CaSO4,MgSO4). Carbonate scale is easily dissolved and removed during pickling.
C, phosphate and calcium phosphate [Ca(PO4)2], this salt scale content is not high. The water body of the hydrothermal converter contains less phosphate, and a part of it comes from the pickling aid, so the phosphate should not be used as the cleaning aid in excess.
D, silicate is calcium silicate, magnesium silicate (CaSiO3, MgSiO3), silicate is not easy to be commonly used acid, (HCL,H2SO4) dissolved, only hydrofluoric acid on silicate scale has a special dissolution cleaning function.
E, oxide scale in addition to containing a large number of inorganic salts, there are a large number of oxides (such as FeO,Fe2O3,Fe3O4,Fe(OH)2, etc.). F, hydroxide area has Mg(OH)2, Fe(OH)2, Fe(OH)3 vein, etc.

The above oxides or hydroxides can be dissolved and removed with acid. In the use of industrial cleaning agents, the company can only better and more effectively use the role of industrial cleaning agents in order to truly solve the problems in production and processing.