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Questions and answers
Questions about maintenance of heat exchange equipment.
Conventional chemical cleaning methods often fail to effectively remove insoluble deposits because they are limited to chemical reactions. These methods dissolve or soften deposits, but can leave particles stuck to the surface. CPR technology solves these problems by combining pulsed hydrodynamic action with chemical cleaning, creating a synergy that breaks down and removes even the most stubborn insoluble deposits.
Cleaning heat exchange equipment with high-pressure jets can be effective, but there is also a risk of damaging the heat exchanger elements.
The main causes of such damage are:
Water jet pressure too high
If the pressure exceeds that allowed for the heat exchanger materials, it may cause:
Using a jet that is too concentrated or the wrong angle of water supply can create a point load on the surface and cause mechanical damage.
Material fatigue
Heat exchangers that have already suffered corrosion, erosion or loss of wall thickness due to service are particularly vulnerable to high pressure. Damaged areas can be destroyed even at relatively low pressures.
Destructive effect of abrasive particles
If abrasive particles (such as sand or sludge residue) are present in the water, they can act as abrasive material and damage the surface of the heat exchanger.
The main causes of such damage are:
Water jet pressure too high
If the pressure exceeds that allowed for the heat exchanger materials, it may cause:
- Deformation or perforation of tubes or plates.
- Formation of microcracks, which over time can become a source of leaks.
Using a jet that is too concentrated or the wrong angle of water supply can create a point load on the surface and cause mechanical damage.
Material fatigue
Heat exchangers that have already suffered corrosion, erosion or loss of wall thickness due to service are particularly vulnerable to high pressure. Damaged areas can be destroyed even at relatively low pressures.
Destructive effect of abrasive particles
If abrasive particles (such as sand or sludge residue) are present in the water, they can act as abrasive material and damage the surface of the heat exchanger.
Heat exchange equipment is an important component of heating and hot water supply systems. However, the accumulation of scale and contaminants on its surfaces significantly reduces the efficiency of these systems. The article discusses the consequences of insufficient coolant preparation, their impact on economic costs and ways to prevent scale formation.
The effect of scale on the efficiency of heat exchange equipment. Contamination of heat exchanger surfaces with scale leads to the following consequences:
- Reduction of heat transfer coefficient. The growth of the scale layer in the range from 0.1 to 1 mm reduces heat transfer by 2-2.5 times, depending on the type of equipment.
- Overconsumption of fuel and electricity. To compensate for thermal energy losses, the coolant consumption increases, which leads to increased resource consumption.
- Increasing temperature pressure. This can cause underheating of the coolant and overheating of the heating surfaces.
Scale on heat exchangers can vary in composition and physical properties:
- Silicate scale. It has low thermal conductivity (0.06–0.23 W/(m K)).
- Gypsum scale. It shows higher thermal conductivity (0.6–2.9 W/(m K)).
- Carbonate scale. The most common, with a thermal conductivity coefficient of up to 7.0 W/(m·K).
General informationHeat exchangers are an integral part of heat and energy supply systems, such as boiler houses, hot water supply systems and large-scale industrial processes. One of the key components of their operation is the flow regime of the coolant, in particular its turbulence.
What is turbulence? Turbulence is an unsteady state of motion of a liquid or gas, characterized by a chaotic change in the speed and direction of the flow. The Reynolds number (Re) is used to measure turbulence, which is determined by the correlation of the flow speed, the density of the coolant and the diameter of the pipeline.
Effect of turbulence on heat transfer Increasing flow turbulence has a positive effect on the efficiency of the heat exchanger due to the following factors:
- Improving heat transfer. The chaotic flow movement provides better mixing of coolants and also removes heat from the surface faster.
- Reducing thermal draft. In turbulent mode, the appearance of "static" heat-insulating layers close to the heating surface is reduced.
- Increased hydrodynamic drag. Turbulence increases pressure differences, which may require increased energy to pump the coolant.
- Depreciation of materials. Strong turbulence leads to faster wear of pipe surfaces and equipment elements.
Scale formation in heat exchangers is a serious issue that affects equipment efficiency and can lead to premature failure. Scale forms due to the precipitation of hardness salts from water when it is heated. The main components of scale are calcium carbonate (CaCO₃) and magnesium carbonate (MgCO₃), along with other mineral deposits.
Scale Formation Process
Scale Formation Process
- Supersaturation with Minerals – Water contains dissolved calcium and magnesium salts, which are in equilibrium with their ionic forms. When heated, the solubility of these salts decreases, leading to precipitation.
- Nucleation (Crystal Formation) – When the ion concentration reaches a critical level, microscopic crystals start forming on the heat exchanger surface or within the water.
- Agglomeration and Crystal Growth – Small crystals merge to form larger structures, gradually growing into solid deposits.
- Adhesion to the Heat Exchange Surface – The formed crystals attach to the heat exchanger surface through electrostatic interactions, mechanical adhesion, and other physicochemical processes.
- Formation of a Solid Layer – Over time, crystal layers densify, forming a hard, poorly soluble deposit that significantly reduces heat transfer efficiency.
- Water Hardness – High concentrations of calcium and magnesium salts in water contribute to the formation of insoluble deposits when heated.
- Temperature Factor – The higher the water heating temperature, the more intensively salts precipitate as solid deposits.
- Operating Duration – The longer a heat exchanger operates without cleaning, the more scale accumulates.
- Water Chemistry – The presence of silicate, sulfate, or iron compounds in water promotes the formation of harder and more difficult-to-remove deposits.
Deviation from the nominal (design) pressure can lead to various negative consequences, reducing the efficiency of the equipment and increasing the risk of its damage. Let's consider the main aspects of this impact.
1. Reducing the coolant pressure
Reduced pressure can occur due to leaks in the system, clogged pipelines, or improper operation of pumping equipment. This has the following consequences:
Excessive pressure is usually caused by improperly sized pumps, clogged valves, or other hydraulic problems. This can lead to the following problems:
Frequent changes in coolant pressure negatively affect the durability and efficiency of the heat exchanger:
To avoid the negative impact of deviations from the nominal pressure, it is necessary to:
Deviation from the nominal pressure of the coolant is a serious factor that can affect the performance and durability of the heat exchanger. To ensure stable and efficient operation of the system, it is important to regularly monitor pressure parameters, eliminate malfunctions in a timely manner and carry out preventive maintenance. This will avoid unforeseen costs, ensure optimal efficiency of the equipment and extend its service life.
1. Reducing the coolant pressure
Reduced pressure can occur due to leaks in the system, clogged pipelines, or improper operation of pumping equipment. This has the following consequences:
- Reduced heat transfer efficiency. At low pressure, the speed of the coolant movement decreases, which leads to uneven heat distribution. As a result, the outlet temperature does not meet the design parameters.
- Cavitation: Low pressure can cause the formation of gas bubbles (cavitation) that destroys the internal surfaces of the heat exchanger, particularly in areas with high flow rates.
- Overheating of system components. If the heat exchanger is used for cooling, a pressure drop can cause components to not cool enough and overheat.
Excessive pressure is usually caused by improperly sized pumps, clogged valves, or other hydraulic problems. This can lead to the following problems:
- Equipment damage. Excessive pressure places additional stress on welds, seals, and heat exchanger materials, increasing the risk of failure.
- Tube and plate warping. Plate heat exchangers can experience plate warping, which impairs contact between them and reduces heat transfer efficiency.
- Increased energy consumption. Excessive pressure can cause additional energy consumption for pump operation, which increases operating costs.
Frequent changes in coolant pressure negatively affect the durability and efficiency of the heat exchanger:
- Water hammer. Sudden pressure drops create shock waves that damage the internal components of the heat exchanger.
- Wear of elements. Constant pressure fluctuations accelerate wear of moving and sealing elements of the system.
- Decreased system accuracy. Unstable pressure makes it difficult to maintain set temperature and heat output parameters.
To avoid the negative impact of deviations from the nominal pressure, it is necessary to:
- Regularly check the system for leaks. Timely detection and elimination of leaks will help maintain the required pressure.
- Monitor the condition of filters and pipelines. Clogging significantly affects pressure and flow rate.
- Adjust pumping equipment. Ensuring adequate pump performance will help avoid both pressure surges and pressure drops.
- Install safety valves. These devices allow you to automatically relieve excess pressure, preventing accidents.
- Regularly diagnose heat exchangers. Preventive maintenance will help identify potential problems at an early stage.
Deviation from the nominal pressure of the coolant is a serious factor that can affect the performance and durability of the heat exchanger. To ensure stable and efficient operation of the system, it is important to regularly monitor pressure parameters, eliminate malfunctions in a timely manner and carry out preventive maintenance. This will avoid unforeseen costs, ensure optimal efficiency of the equipment and extend its service life.
When choosing heat exchange equipment, the question often arises: which is better - a shell-and-tube or plate heat exchanger? The answer depends on many factors: temperature, pressure, operating conditions, and maintenance costs.
Shell and tube heat exchangers
This classic type of design consists of a bundle of pipes located inside a casing.
✅ Advantages:
These devices consist of thin plates between which coolants move.
✅ Advantages:
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Shell and tube heat exchangers
This classic type of design consists of a bundle of pipes located inside a casing.
✅ Advantages:
- Withstands high temperatures and pressures (up to 100 bar and above).
- Less prone to clogging when working with dirty or viscous liquids .
- Durable – lasts for decades with proper maintenance.
- Bulky and heavy , takes up a lot of space.
- Higher production and installation costs .
- Difficulties with cleaning – you need to disassemble the structure .
These devices consist of thin plates between which coolants move.
✅ Advantages:
- Compactness – takes up 3-5 times less space than a shell-and-tube system.
- High efficiency – transfers heat more efficiently due to the large contact area.
- Easy cleaning – collapsible models are quickly disassembled and washed.
- Flexibility – you can increase capacity by adding plates.
- Limited working pressure and temperature (up to 25-30 bar).
- Sensitive to contamination – can quickly become clogged when working with suspensions.
- Periodic replacement of seals in collapsible models is required.
- For high temperatures and pressures → Shell and tube
- For compactness and high efficiency → Plate
- For aggressive environments → Shell-and-tube made of corrosion-resistant materials
- For flexibility and easy maintenance → Plate-type
📞 Contacts : +380672940777
📧 E-mail : info@imp-trade.com
🌐 Website : imp-trade.com
Heat exchangers play a key role in heating, cooling, and industrial processes. Their contamination leads to reduced efficiency, increased energy costs, and premature failure. Let's examine why regular heat exchanger cleaning is economically more beneficial than major repairs or equipment replacement.
1. Reduced Energy Costs
Deposits inside heat exchangers impair heat transfer, forcing equipment to operate under increased load. Studies show that even a small layer of scale (just 1 mm) can increase energy consumption by 10–15%. Regular maintenance prevents these losses.
2. Extended Equipment Lifespan
Without timely cleaning, scale and corrosion destroy heat exchange surfaces. As a result, there is a risk of leaks, leading to expensive repairs or replacement of units. Preventive cleaning extends the operational life of heat exchangers by 30–50%.
3. Minimization of Unplanned Downtime
A heat exchanger breakdown during the peak heating season or a critical production process can cause serious financial losses. Preventive maintenance helps identify problem areas in advance and address them without disrupting enterprise operations.
4. Lower Repair Costs
Scheduled cleaning is several times cheaper than major repairs or replacing a heat exchanger. Moreover, the use of specialized chemical reagents and hydropulse technology allows the procedure to be carried out without dismantling, saving time and resources.
5. Environmental Safety
Contaminated heat exchangers increase CO2 emissions due to inefficient fuel combustion. Regular cleaning reduces environmental impact and helps comply with ecological regulations.
Conclusion
Preventive maintenance of heat exchangers is not just a precaution but a real cost-saving measure. Regular cleaning reduces energy costs, extends equipment lifespan, prevents unplanned shutdowns, and lowers repair expenses. Modern technologies, such as hydropulse chemical cleaning, enable effective maintenance of heat exchangers without significant financial investment. By investing in prevention, companies save on repairs and enhance the overall efficiency of their engineering systems.
1. Reduced Energy Costs
Deposits inside heat exchangers impair heat transfer, forcing equipment to operate under increased load. Studies show that even a small layer of scale (just 1 mm) can increase energy consumption by 10–15%. Regular maintenance prevents these losses.
2. Extended Equipment Lifespan
Without timely cleaning, scale and corrosion destroy heat exchange surfaces. As a result, there is a risk of leaks, leading to expensive repairs or replacement of units. Preventive cleaning extends the operational life of heat exchangers by 30–50%.
3. Minimization of Unplanned Downtime
A heat exchanger breakdown during the peak heating season or a critical production process can cause serious financial losses. Preventive maintenance helps identify problem areas in advance and address them without disrupting enterprise operations.
4. Lower Repair Costs
Scheduled cleaning is several times cheaper than major repairs or replacing a heat exchanger. Moreover, the use of specialized chemical reagents and hydropulse technology allows the procedure to be carried out without dismantling, saving time and resources.
5. Environmental Safety
Contaminated heat exchangers increase CO2 emissions due to inefficient fuel combustion. Regular cleaning reduces environmental impact and helps comply with ecological regulations.
Conclusion
Preventive maintenance of heat exchangers is not just a precaution but a real cost-saving measure. Regular cleaning reduces energy costs, extends equipment lifespan, prevents unplanned shutdowns, and lowers repair expenses. Modern technologies, such as hydropulse chemical cleaning, enable effective maintenance of heat exchangers without significant financial investment. By investing in prevention, companies save on repairs and enhance the overall efficiency of their engineering systems.
