Hydrochemical cleaning of boilers. Flushing of boilers and heat exchangers: technology, chemicals

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Chemical flush gas boilers and heat exchangers

An essential condition for high performance and full-fledged functioning of boiler equipment is regular flushing. Chemical washing is usually applied to both household and industrial boilers. Minimize the corrosive effect on metal parts possible only with proper monitoring of the state of the boiler unit. If you neglect regular cleaning of the system, the heating capacity of the boiler will decrease, and scale will form on its inner surface.

Chemical washing is the most effective way cleaning, allowing you to maintain the performance of the boiler at the proper level.

Estimated cost of services

The cost of work is formed based on the model of the boiler, location, heat exchange surface area, water volume and degree of contamination.

The cost of work is formed based on the heat exchanger model, location, heat exchange surface area, water volume.

What explains the need to flush the boiler and heat exchange equipment chemicals?

In practice, the quality of water for heating networks does not correspond to established standards. Failure to comply with the regulations when putting the system into operation starts the process of sedimentation of excess salt and other impurities on the surface of the pipes. Concerning hydraulic mode is disturbed, the useful volume of networks is reduced, which leads to a complete imbalance and threatens the integrity of the system. It is not possible to carry out mechanical cleaning of pipes and equipment due to the lack of technical capacity, so chemical flushing becomes almost the only and most effective method cleaning the system.

Stages of flushing boiler equipment:

1. Preliminary inspection of the inner surface and heating elements.
2. Determining the level of contamination and selection chemical reagents.
3. Direct washing of boiler equipment under the strict supervision of specialists.
4. Drawing up a report on the work done.

Chemical flushing of the boiler with a sludge level of more than 1500 g/m3 or with a content of silicic acid (sulphates) in sediments above 10% is carried out in two stages with preliminary alkalization before the acid stage.
If the amount of sludge working surface boiler unit is more than 3000 - 4000 g / m, an alternation of acid and alkaline treatment stages is required.
In certain cases, acid flushing of the boiler must be preceded by mechanical (hydrodynamic) flushing of sludge-laden areas, which makes it possible to get rid of porous and non-cemented deposits. In this case, the duration of cleaning and the amount of chemicals needed for effective flushing is significantly reduced.

Basic requirements for the chemical washing process:
- the use of safe detergents to avoid damage to the surfaces of the boiler;
- possibility efficient removal deposits without the formation of insoluble compounds.

Flushing of heat exchangers

Regular flushing will not only increase the performance of the heat exchanger and reduce the risk of defects on the working surfaces, but also prevent premature equipment failure.
Chemical flushing is necessary to clean the internal surfaces of the heat exchanger from harmful deposits that reduce the thermal conductivity of the system. Excessive pollution interferes with the productive operation of the heat exchanger and makes it necessary to take measures to artificially adjust the temperature regime. Regular flushing helps to avoid unforeseen accidents and damage to heat exchange equipment.

Chemical flushing of the heat exchanger is carried out in several stages:

1. The introduction of a solution with active substances into the heat exchanger, which, when reacting with deposits on internal surfaces split them and remove them from the unit.
2. Washing the plates of heat exchange equipment with water in order to remove the residual reagent. In case of inefficient flushing, active substances can react with the coolant, which will lead to damage to the equipment.
3. Alkaline washing of internal surfaces.
4. Hydraulic tests of the newly commissioned heat exchange equipment.

Examples of contamination of boiler surfaces

Samples of the maximum pollution extracted from the water part of the heating surfaces of the boiler

Boiler water path - scale deposits before and after boiler flushing

Smoke tubes

Connection of flame tube and tube plate

BOILER ERROR

Chemical flushing and cleaning of heating boilers should be carried out regularly, since the gradual accumulation of scale, deposits, as well as corrosion of the internal surfaces of pipes and elements of water heating boilers during their operation will inevitably lead to a decrease in the efficiency of the boiler, and consequently, the entire system as a whole. Moreover, it may cause instability or decrease in thermal conductivity, damage pipes, or cause equipment malfunction. And, of course, all this is followed by an inevitable increase in energy costs in order to maintain a given temperature regime. Therefore, chemical flushing is a guarantee of their long and uninterrupted operation, prevents malfunctions in the operation of equipment and greatly reduces the material costs of maintaining their performance.

If during operation heating equipment all operating regulations are fully observed, then deposits are usually formed from iron oxides. If, for some reason, the regulations are violated, then other elements may also be included in the sediments - compounds of phosphates, copper, silicon, and also carbonates.

Chemical flushing and cleaning of boilers consists of several stages:

1. flushing network water internal surfaces of boilers.
2. Alkalinization of boilers.
3. Thorough flushing of boilers with technical liquids.
4. Filling the acid wash solution and circulating it inside the boiler.
5. Subsequent flush.
6. Passivation and neutralization after chemical cleaning.
7. Precleaning process water boilers.
8. Final flushing of the internal surfaces of the boilers with clean running water.

If on the inner surfaces of the water heating elements accumulated a large number of deposits, then boilers should be carried out in two stages. In this case, it is recommended to carry out intermediate alkalization between acid stages or before treatment with chemical solutions. In particular advanced cases several alternations of alkaline and acid treatments may be required.

There may also be situations when, before starting chemical cleaning, it would be advisable to perform a mechanical flushing of the most contaminated boiler elements, which will help remove loose, loose deposits, thus reducing sludge, and reducing the number of required boiler cleaning stages and the consumption of chemical detergents. In addition, it is imperative to organize timely chemical control over certain operations, which usually consists in measuring the pH level and the concentration of chemical acid, iron content, soda ash or caustic soda (when alkalizing the boiler).

Obviously, in an efficient and long work any heating boiler importance has a heat exchanger. Rust, scale and other harmful deposits significantly reduce the efficiency of heat exchange processes, increase material costs and increase the amount of harmful emissions into the environment. However, many problems can be avoided at an early stage if heating boilers are carried out in time.

It should be noted that untimely chemical cleaning of boilers, and moreover, a complete refusal to carry out these actions will entail not only a constant increase in energy costs to maintain the desired temperature, but also significant costs for restoring the equipment’s operability, and in some cases for restoration work due to occurrence emergency. Moreover, it absolutely does not depend on the type of boiler used (whether brazed, shell-and-tube or lamellar). equally detrimental effect on the work of each of them. To date, there are endless disputes among specialists about which manufacturers have water heating equipment that works better and more efficiently. But the reasons for the decline in performance or failure remain common to almost all boilers.

There are two types of descaling from the boiler heat exchanger - cleaning of corrosive deposits from the system and the main heat exchanger of the boiler and cleaning of solid deposits.

A flushing station is connected to the heating system with a tank in which Chemical substance, which is mixed with water of the required concentration and distributed through the heating system. The pump distributes these chemicals at high speed through the boiler heat exchanger. This dirty liquid is pumped out of the return at high speed and replaced with fresh water to ensure sufficient chemical flow. This mixture is in turn drained and replaced with new water and corrosion inhibitor. The whole process takes several hours.

Scale in the boiler heat exchanger is removed when the heat exchanger accumulates a significant thickness of calcium on its surface, and it isolates the water from the heat source, thereby reducing performance.

This effect occurs only in the heat exchanger in which there is tap water. AT closed systems there is a large content of large amounts of calcium. There are always two ways out, either it is necessary to replace the old heat exchanger with a new one, or to remove scale with acid. Descaling with acid is considered a simpler and cheaper procedure.

Why is it necessary to flush the boiler heat exchanger?

Boiler flushing is effective way removing sediment and dirt, and what builds up inside your heating system over time. If you notice a gradual decrease in the efficiency of the boiler, this sludge envelops the internal pipelines and reduces the circulation of the heat carrier in the heating system.

Sludge and scale are formed mainly in old boilers or when replacing an old boiler with a new one in older systems. If you have replaced the old boiler with a new one, dirt still remains in the heating system, and when starting up, all the dirt can get into the new boiler, which will reduce its efficiency and service life.

Some problems that can be avoided by flushing:

• Cold Radiators
• Problems with coolant circulation
• Pipe blockages
• Internal corrosion
• Blockage of the entire system
• Noise during boiler operation
• Double-circuit boilers cannot provide a constant hot water at a stable temperature
• Permanent failure circulation pump
• A sharp increase in the pressure of the heating system
• Leaks in connections and heating radiators
• The heating system in the house is slowly heating up

As a result of washing the boiler, you will receive:

• Fuel economy when heating the boiler up to 25%
• Extended boiler and pump life
• Full heat transfer from heating radiators
• High efficiency heating system that will reduce gas costs
• Cleaning the boiler heat exchanger will remove unpleasant noises and extend the life of the boiler
• When cleaning the system from contaminated water, it will help to avoid internal corrosion of the heating system

What causes scale to form on the boiler heat exchanger

The heating system includes a boiler, radiators, and connecting pipes. This system is filled with water, which is heated in a boiler and circulated by means of a pump through the radiators. Water carries dissolved oxygen, which reacts with metal in radiators and pipes as metal oxide. This water may also high level calcium and other minerals that come from the plumbing. Over time, the levels of these impurities can increase and cause problems for the entire heating system. These contaminants can form deposits inside radiators, which can reduce or shut off flow. hot water to these radiators. These impurities can form a layer on the inside of boiler heat exchangers and reduce the efficiency of such boilers. If this is not stopped and the heat exchanger is not flushed, the layer will grow and the boiler will begin to make noise when it is working.

Contact our office and we will flush the boiler heat exchanger at affordable prices.

The price of flushing the boiler heat exchanger

№	Name	Unit.	Price, rub
1	Chemical flushing of a wall-mounted boiler - one circuit of a bithermic heat exchanger. (Additionally paid: reagent (500 ₽/liter), neutralizer (300 ₽/liter, ~1 liter required for every 25 kW)	PCS	4500
2	Chemical flushing of wall-mounted boiler - heat exchanger heating system. (Additionally paid: reagent (500 ₽/liter), neutralizer (300 ₽/liter, ~1 liter required for every 25 kW)	PCS	4500
3	Chemical washing of a wall-mounted boiler - hot water heat exchanger. (Additionally paid: reagent (500 ₽/liter), neutralizer (300 ₽/liter, ~1 liter required for every 25 kW)	PCS	2850
4	Chemical flushing of the floor boiler. (Additionally paid: reagent (500 ₽/l), neutralizer (300 ₽/l, you need ~ 1 liter for every 25 kW), it is desirable to have an organized drain into the sewer and an inspection hole)
4.1	Boilers from 30 to 49 kW	PCS	14000
4.2	Boilers from 50 to 99 kW	PCS	17000
4.3	Boilers from 100 to 149 kW	PCS	23000
4.4	Boilers from 150 to 199 kW	PCS	30000
4.5	Boilers with power from 200 to 250 kW	PCS	36000
4.6	Boilers from 300 to 499 kW	PCS	58000
4.7	Boilers from 500 to 999 kW	PCS	76000
4.8	Boilers from 1 to 2.4 MW	PCS	120000

The company "ASGARD-Service" carries out chemical washing of boilers of various types:

• Steam, hot water (by type of heat carriers);
• Gas, solid fuel, diesel (according to the type of fuel);
• Boiler equipment.

Figure 1. Boilers

The problem with boiler fouling is a periodic and inevitable phenomenon, corresponding to the fuel used, the type of heat carrier, and water treatment. When using diesel fuel, the pollution of the furnace space occurs 3 to 4 times faster than when using gas. Using solid fuel(wood/coal) boilers may be contaminated according to an even tighter schedule. The space filled with coolant is distinguished by other types of pollution (salts, rust, etc.). The occurrence of such situations affects the deterioration of the economic component of the enterprise and can lead to considerable losses.

Figure 2 and 3. Pollution on boilers.

Procedure for chemical washing of boilers

This method of cleaning boilers and boiler equipment is the simplest and most reliable. When performing it, specialists use acidic reagents that contribute to quick and high-quality loosening, removal of deposits, scale and other types of deposits from the walls of boilers. Each boiler manufacturer develops its own recommendations for the selection of cleaning agents. Therefore, guided by their recommendations, the necessary solution for washing is selected. The actions of our specialists are fully consistent with the documents of manufacturers, working documentation.

Figure 3. The result of cleaning.

All work on cleaning boilers is carried out by our specialists in accordance with RD 34.37.402-96 " standard instruction on operational chemical cleaning of hot water boilers. This document states that all types of deposits can be cleaned using the following detergents: hydrochloric acid, sulfuric acid, as well as sulfuric acid with ammonium hydrofluoride, sulfamic acid, low molecular weight acid concentrate (NMA).

With specific detergent our specialists are determined after agreement with the customer and identifying the degree of contamination of the equipment that needs cleaning. It should be noted that the use of any acidic solution is made in combination with a corrosion inhibitor to protect the metal of the boiler.

The cleaning procedure includes:

• Calculation required amount reagent corresponding to the volume of the boiler;
• Filling the reagent inside the boiler;
• Creation closed circuit to circulate the solution.

During circulation, all types of deposits are separated, passing into solution and settling in an intermediate tank included in the flushing system. A few hours of work are enough to completely clean the boiler and prepare for work.

The time of the cleaning procedure corresponds to the degree of contamination of the boiler and can be either several hours or several days (for complete completion chemical reaction). These parameters are used to calculate the cost of work taking place at a particular facility.

Flushing of boilers must be carried out carefully and systematically. The use of hard water leads to the formation of scale and sediment. If the cleaning procedure is neglected, the boiler may fail prematurely. To understand how pollution occurs, you can imagine an ordinary kettle that heats water several times every day. After some time, scale forms on the walls of the kettle, which leads to a slower heating of the water. The same goes for the boiler.

Flushing the boiler from scale: the consequences of ignoring

Modern highways use ordinary hard water, which quickly leads to the fact that the equipment is covered with scale from the inside. Flushing of boilers must be carried out on a regular basis. If cleaning is not done on time. The consequences can be the most unpredictable, but definitely unpleasant.

If the boilers are not flushed from time to time, they will start to overheat during operation.

The device of the gas boiler is such that the coolant coming from the return line cools the cavities of the heating elements located inside. The coolant cannot effectively cool the elements if they are covered with a thick layer of scale. If the boiler constantly overheats, then soon it will stop working altogether.

What will ignoring flushing lead to:

• Scale consists of mineral deposits that do not contribute to thermal conductivity. Scale causes the water to heat up slowly, which takes a lot of more electricity. A thick layer of scale leads to an increase in gas consumption, which increases the price for using the boiler.
• Scale can lead to boiler failure due to the difficult passage of the coolant. This increases the load on the circulation pump, which leads to its early breakdown.

Before flushing the boiler, it is important to pay attention to what liquid flows through the line. The need for frequent flushing will be due to very hard and contaminated water. In order to reduce the frequency of cleaning, it is necessary to use antifreeze - it is important that it is not expired.

Options: how to clean the boiler from scale

If purified water is used in the main, then the boiler can be flushed once every four years. Using the normal running water may cause damage to the boiler, as such water is too hard. The efficiency of the boiler decreases if cleaning is not carried out for a long time.

The easiest and most effective cleaning method is manual washing - you can do it yourself.

To carry out a simple cleaning of the heat exchanger, it is necessary to dismantle the boiler. Cleaning can be done in several ways: mechanical and washing. When dismantling the boiler, you need to be careful and accurate.

Options for cleaning the boiler from scale:

• Mechanical. Allows you to remove plaque and other mechanical particles using a vacuum cleaner, scraper or metal brushes.
• Flushing. Plaque coating of heat exchanger parts can be soaked in a special solution. This method is good for cleaning boilers with two circuits, as they become dirty very quickly and intensively.

The most effective type of purification is considered to be pre-treatment of water. The boiler can be protected against scale formation by installing scale filters. If extraneous sounds are detected in the heating system, it is necessary to check whether mechanical impurities have appeared in the boiler.

How to descale the boiler: flushing methods

Impurities definitely negatively affect the working condition of the boiler. Too hard water always leads to the formation of scale, which can disable the entire system. Usually, users install a strainer, which should protect the boiler from scale formation.

Too much potassium and magnesium in the water leads to the formation of impurities, which, during crystallization, settle on the inner walls of the equipment.

Particles formed from the water as a result of its heating move through the pipes, causing noise. Usually, equipment is installed in houses and apartments that has a relatively small size. Drainage of particles that pollute the system does not occur, which ultimately leads to bad job equipment or damage.

Descale options:

• Use of reagent acids. Using strong acids is an effective way to get rid of scale. They easily remove iron deposits and carbonate scale.
• To remove silicate scale, it is necessary to use substances that contain a lot of alkali.
• To flush the boiler from scale, you can use a collapsible or non-collapsible cleaning method.

The non-separable cleaning method involves the use of reagents, the use of which does not require the process of dismantling the boiler. Most often, the method of this cleaning involves the use of three-component boosters, which perfectly clean boiler equipment. The booster consists of three blocks: a reagent tank, a heating tank and a pump.

Chemical cleaning of boilers from scale

The chemical cleaning method will help to clean the boiler quickly and effectively, which involves a preliminary determination of the composition of scale and its nature. This method is considered the simplest, fastest and most effective. Before cleaning it is necessary to take a scale sample from different places, and then deal with the definition of the average sample.

Dry cleaning involves cleaning the walls of the boiler by exposing it to acids: hydrochloric, sulfuric or alkalis: soda, soda, trinatophosphate.

Carbonic acid contributes to the rapid dissolution of carbonate and phosphate deposits. Hydrochloric acid interacts with carbon scale, forming chloride compounds of calcium, magnesium and carbon dioxide, which dissolve easily. Descaling of phosphate and silicate scales is more difficult, but efficiency can be improved by adding fin acid to the cleaner.

Types of acids for cleansing:

• Salt;
• sulfuric;
• Sulfamic;
• sorrel;
• Lemon.

When choosing acids, it is important to pay attention to their availability, cost, efficiency and environmental friendliness. Clean the boiler by chemical means you can do it yourself, but you need to be extremely careful. The most popular in the West are reagents that belong to the class of chemical acids. Chemical cleaning- the most reliable and efficient view descaling, if all reagents are selected correctly.

Flushing heating boilers (video)

Availability gas boiler says that there are no problems in the house in order to heat the water. The problem of a gas boiler and heating can be pipe contamination, which has direct influence for boiler operation. The only way to protect your equipment from scale is through regular cleaning. The cleaning scheme should be thought out taking into account how polluted the water in the line is. chemical agent to combat scale is considered the most effective. Protecting the boiler from pollution means extending its service life by long years forward. You can also make a booster with your own hands for washing boilers.