What are the energy-saving methods for small boilers?

1. Thermal recovery and utilization of coal slag； 2. Recovery and reuse of steam condensate ；

The soda water system uses a hydraulic coupler for speed control, while the air and flue gas system employs frequency conversion devices to regulate air volume. If space permits, additional heat exchange surfaces can be added to the rear heating surface.

Small boilers generally have a higher carbon content in their ash and slag, as well as greater heat losses from the exhaust gases. . If constrained by combustion conditions, it is generally difficult to reduce the carbon content in the ash; however, by properly adjusting the air supply to the boiler, it is possible to lower the oxygen content in the exhaust gases to some extent, thereby reducing heat losses from the exhaust gases. . For boilers with high flue gas temperatures, it is possible to consider installing economizers, air preheaters, etc. Furthermore, for small boilers, due to the low slag discharge volume, a slag heat recovery system is not cost-effective. Of course, proper coal preparation and blending can also ensure that the boiler operates in good condition.

The energy-saving upgrades for small boilers generally do not yield significant benefits; attention must be paid to economic considerations to ensure that the costs are not greater than the advantages.

Recycling of distillation condensate water, maintaining feedwater temperature, and reducing wastewater discharge

　　① Add fuel； 　　The hydrocarbons processed by the fuel energy saver undergo changes in their molecular structure: there are more small molecules, the distance between molecules increases, and the viscosity of the fuel decreases. As a result, the degree of atomization and refinement of the fuel before combustion is greatly improved; it burns fully upon entering the combustion chamber under conditions of low oxygen levels. This allows the air supply required for the combustion equipment to be reduced by 15% to 20%, preventing heat from being carried away through the flue gases, and resulting in a decrease in flue gas temperature by 5°C to 10°C. After the fuel for combustion equipment is treated by an economizer, the combustion efficiency improves, allowing for a fuel savings of 4.87% to 6.10%. Moreover, the flame becomes brighter and more intense, black smoke disappears, and the furnace chamber becomes clear and transparent. Thoroughly remove coking from the combustion nozzles and prevent re-coking. It eliminates the accumulation of residues on the furnace walls caused by incomplete combustion of fuel, thereby achieving environmental protection and energy savings. **It reduces the pollution of the air caused by the exhaust gases emitted from combustion equipment; harmful components in these exhaust gases such as carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC) are significantly reduced, with the emission of harmful exhaust gases being cut by more than 50%. At the same time, the dust content in the exhaust gas can be reduced by 30%–40%. Installation location: Installed between the oil pump and the combustion chamber or nozzle; the ambient temperature should not exceed 360°C. 　　② Install an energy saver for condensing gas boilers ； 　　The exhaust gas from gas boilers contains up to 18% water vapor; the large amount of latent heat contained in it goes unutilized, resulting in high exhaust gas temperatures and significant losses of sensible heat. After burning, natural gas still emits pollutants such as nitrogen oxides and a small amount of sulfur dioxide. Reducing fuel consumption is the best way to cut costs. The condensing gas boiler economizer can be installed directly in the flue of existing boilers to recover energy from the hot exhaust gases, thereby reducing fuel consumption with significant economic benefits. At the same time, the condensation of water vapor helps to absorb pollutants such as nitrogen oxides and sulfur dioxide from the exhaust gases, reducing pollutant emissions and thus playing an important role in environmental protection. 　　③ Adopt condensing waste heat recovery boiler technology ； 　　In traditional boilers, the flue gas temperature is generally between 160 and 250°C; the water vapor in the flue gas remains in a superheated state, so it cannot condense into liquid water and release its latent heat of vaporization. As is well known, the thermal efficiency of a boiler is calculated based on the lower heating value of the fuel, without taking into account the heat losses associated with the latent heat of vaporization in the higher heating value of the fuel. Therefore, the thermal efficiency of conventional boilers generally only reaches 87%–91%. Condensing waste heat recovery boilers reduce the flue gas temperature to 50–70°C, fully recovering the sensible heat in the flue gas as well as the latent heat of vaporization of water vapor, thereby improving thermal efficiency ； Condensate water can also be recycled. 　　④ Heat pipe waste heat recovery technology is used at the rear of the boiler ； 　　Waste heat is the energy that remains unused in energy utilization equipment under certain economic and technical conditions; in other words, it is excess or discarded energy. It includes seven types: waste heat from high-temperature exhaust gases, waste heat from cooling media, waste heat from exhaust gases and wastewater, waste heat from high-temperature products and slag, waste heat from chemical reactions, waste heat from combustible exhaust gases, liquids and wastes, as well as the residual pressure of high-pressure fluids. According to surveys, the total waste heat resources in various industries account for approximately 17% to 67% of their total fuel consumption, and the waste heat resources that can be recovered make up about 60% of the total waste heat resources. 　　Superconducting heat pipes are the main heat conduction elements in heat pipe waste heat recovery systems, and they differ fundamentally from ordinary heat exchangers. The heat exchange efficiency of a heat pipe waste heat recovery unit can exceed 98%, a level that no ordinary heat exchanger can achieve. The heat pipe waste heat recovery unit is compact, accounting for only 1/3 the size of a regular heat exchanger. Its working principle is as shown in the figure: the left side is the flue gas channel, the right side is the clean air (water or other medium) channel, with a partition in the middle to keep them separate and prevent interference. The hot flue gas is discharged through the left channel; as it is expelled, it flows over the heat pipes. When the temperature of the flue gas exceeds 30°C, the heat pipes become active and transfer heat to the right side automatically. At this point, the left side of the heat pipes absorbs heat, and the temperature of the hot flue gas drops as it passes through these heat pipes; the heat is then absorbed by the heat pipes and transferred to the right side. At room temperature, clean air (water or other media), driven by a blower, flows in the opposite direction along the right channel to wash over the heat pipe; at this point, heat is released on the right side of the heat pipe, heating the clean air (water or other media). The temperature of the air rises as it passes through the heat pipe. A waste heat recovery device composed of several heat pipes is installed at the boiler’s exhaust outlet; it absorbs the heat from the flue gases and transfers it rapidly to the other end, thereby reducing the exhaust temperature to near the dew point and minimizing heat loss. The heated clean air can be used to dry materials or fed back into the boiler for reuse. Improve the thermal efficiency of boilers and industrial furnaces, reduce fuel consumption, and achieve energy savings. 　 　　When designing and manufacturing industrial fuel, gas, and coal-fired boilers, in order to prevent corrosion of the heat-exchanging surfaces at the rear of the boiler as well as ash buildup, the exhaust gas temperature under standard conditions is generally not lower than 180°C, and can reach up to 250°C. The emission of hot flue gases not only results in significant waste of thermal energy but also causes environmental pollution. 　 　　A heat pipe waste heat recovery unit can recover the heat from flue gas; the recovered heat can be used to heat water for use as make-up water in boilers and for domestic purposes, or to heat air for use as combustion air in boilers or for drying materials. It saves fuel costs, reduces production expenses, cuts exhaust emissions, and achieves both energy conservation and environmental protection. The investment in renovation pays off within 3-10 months, yielding significant economic benefits. 　　⑤ Adopt scale prevention and removal technologies ； 　　By using boiler descalers and electronic scale preventers, optimizing the water and steam circulation system, and properly controlling the boiler’s blowdown rate, scale can be reduced and the boiler’s thermal efficiency improved. 　　⑥ Adopt fuel additive technology ； 　　Additives are incorporated into the fuel to optimize it, thereby reducing soot formation and improving thermal efficiency ； 　　⑦ Adopt new fuel ； 　　New eco-friendly fuel oils are used to reduce fuel costs. 　　⑧ Oxygen-enriched combustion technology is employed ； 　　The oxygen content in the air is ≤21%. The combustion in industrial boilers also takes place under such air conditions. Practice has shown that when the oxygen content in the gas burned in the boiler exceeds 25%, energy savings of up to 20% can be achieved ； The boiler’s startup heating time is reduced by 1/2–2/3. Oxygen enrichment, on the other hand, involves using physical methods to extract oxygen from air, resulting in an oxygen content in the resulting gas of 25%–30%. Oxygen-enriched combustion assistance is a cutting-edge energy-saving and environmental protection technology. Over the past decade or so, driven by increasing environmental regulations and the need to save energy, oxygen-enriched combustion has emerged as a new combustion technology that has seen rapid development around the world. Nowadays, some developed countries in the West require that all new industrial furnaces and boilers use oxygen-enriched air instead of ordinary air for combustion. 　　⑨ Adopting swirl combustion boiler technology ； 　　As is well known, traditional boilers have two major drawbacks: first, smoke and dust are emitted during combustion, serving as a significant source of pollution ； Second, the coal cinders are not burned fully, resulting in extremely severe energy waste. Compared with traditional industrial boilers, the new pure smokeless and energy-saving swirl combustion boiler technology has absolute advantages. It saves 30%~35% more coal compared to hand-fired boilers, and 25% more coal compared to chain-type automated boilers. Thanks to the use of PID frequency conversion and ABM power-saving systems, the pure smoke-free energy-saving combustion technology enables a 40% reduction in energy consumption compared to traditional boilers. It allows for more than 90% combustion and utilization of volatile substances, whereas traditional boilers achieve only around 78% combustion efficiency for such substances, with 22% of the emissions ending up in the atmosphere. The pure smoke-free energy-saving swirl combustion technology achieves a ash combustion efficiency of 97%, while traditional boilers have an ash combustion efficiency of only around 80%. It is for these reasons that this technology allows the furnace temperature to be increased from 1200°C to around 1500°C, thereby improving combustion efficiency, saving fuel, and meeting customers’ needs. 　　⑩ Replace with air-source heat pump hot water unit technology ； 　　Replace the existing fuel (gas) hot water boiler with an air-source heat pump hot water unit ； Energy consumption can be reduced by 30% to 50%. ⑾ Coal-fired boilers can be converted into fuel (gas) boilers ； 　　Total heat recovery technology for flue gas from fuel and gas boilers I. Overview Generally, the average thermal efficiency of domestic fuel (diesel) and gas boilers is around 87%; approximately 10% of the thermal energy is released into the atmosphere through the boiler’s flue gas. The temperature of this flue gas ranges from 180°C to 250°C, which not only results in significant waste of energy but also causes serious environmental thermal pollution. 　　In a normal gas boiler, to produce 1 ton of steam, it is necessary to consume around 80 Nm3 of natural gas, resulting in 1300 Nm3 of flue gas, of which 15% to 19% is steam that is in a superheated state. This steam cannot condense into liquid water in the high-temperature flue ducts, thereby preventing the release of its latent heat of vaporization. The amount of latent heat in the flue gas is enormous, reaching over 56,000 kcal, which accounts for about 6% of the lower heating value of natural gas; this represents an astonishing level of waste. 　　II. Energy-saving Measures Recycling the waste heat from boiler flue gas is an important way to save energy in boilers. The calorific value of flue gas is high; merely the latent heat of vaporization of water vapor is sufficient to preheat the boiler feed water to above 100°C. This preheated water can be used for feeding the boiler, and any excess hot water can also be utilized to heat water for domestic use. 　　The heat loss due to flue gas emission from fuel and gas boilers is approximately 8%–16%, the heat loss due to waste discharge is about 1%, heat loss through the boiler body itself is 1%–2%, and incomplete combustion accounts for 1%. The effective utilization rate of heat is around 80%–91%. The flue gas consists of 68% N2, 11% CO2, 16% H2O, 4% O2, 2 ppm of SO2, and 80 ppm of NOx. If the flue gas temperature is 200°C, it can be reduced to below 70°C (or even to 45°C) using a high-efficiency total heat recovery exchanger. This allows the boiler feed water at 20°C to be raised to 85°C, resulting in significant energy savings. Moreover, since oil and gas contain very little sulfur, the SO2 content in the flue gas is low; most of this sulfur gets dissolved in the flue gas condensate and is thus removed from the exhaust gases. Additionally, the flue gas waste heat recovery units are made of stainless steel, ensuring reliable corrosion resistance. As a result, the service life of the entire system is 5 to 6 years or more. 　　III. Total Heat Recovery Exchanger The total heat recovery exchanger is made of stainless steel plates; it can be used alone or, as needed, multiple units can be installed in parallel within one housing. The exchanger has an inlet for water, a drain outlet for condensate at the bottom, and it can also be disassembled for cleaning. As the high-temperature flue gas passes through the heat exchanger, it heats the boiler water, causing the temperature of the flue gas to drop below the dew point. This allows for the maximum absorption of the sensible heat contained in the flue gas. At the same time, the water vapor in the flue gas is condensed into water, releasing a large amount of latent heat; this process enables full heat recovery. The heat recovery resulting from vapor condensation is a phase-change heat transfer process, and the heat transfer efficiency in such processes is very high. 　　Dew forms in the total heat recovery heat exchanger for flue gas; it condenses into water and, at the same time, absorbs some of the CO2 and NOx present in the flue gas, thereby purifying the flue gas and contributing to environmental protection. The condensate water is discharged into the neutralization tank through guide pipes, where it reacts with the alkaline lime water in the tank before being released. 　　The flue gas resistance of flue gas heat recovers is generally below 200 Pa, with some systems having a resistance of only 100 Pa. The volume and weight of such heat exchangers are 1/10 to 1/5 or more smaller than those of conventional heat exchangers, making them highly suitable for use in small boiler rooms in urban areas. The service life of these devices is 5 to 6 years. 　　IV. Energy-saving and environmental protection benefits of this technology: 1. The thermal efficiency of the boiler increases by more than 10%; calculated based on the lower heating value of gas, the boiler’s thermal efficiency can even exceed 100%. 　　2. Harmful components in the flue gas, such as CO2 and NOX, are absorbed by the condensate water, which is beneficial for environmental protection.

Heat pipe waste heat recovery technology is used at the rear of the boiler； - N9 {2 E8 I& i* l4 H0 Y8 y 　　Waste heat is the energy that remains unused in energy utilization equipment under certain economic and technical conditions; in other words, it is excess or unused energy. It includes seven types: waste heat from high-temperature exhaust gases, waste heat from cooling media, waste heat from exhaust gases and wastewater, waste heat from high-temperature products and slag, waste heat from chemical reactions, waste heat from combustible exhaust gases, liquids and wastes, as well as the residual pressure of high-pressure fluids. According to surveys, the total waste heat resources in various industries account for approximately 17% to 67% of their total fuel consumption, and the waste heat resources that can be recovered make up about 60% of the total waste heat resources. - x' l0 `0 U. _) ? Superconducting heat pipes are the main heat conduction elements in heat pipe waste heat recovery systems, and they differ fundamentally from ordinary heat exchangers. The heat exchange efficiency of a heat pipe waste heat recovery unit can exceed 98%, a level that no ordinary heat exchanger can achieve. The heat pipe waste heat recovery unit is compact, accounting for only 1/3 the size of a regular heat exchanger. Its working principle is as shown in the figure: the left side is the flue gas channel, the right side is the clean air (water or other medium) channel, with a partition in the middle to keep them separate and prevent interference. The hot flue gas is discharged through the left channel; as it is expelled, it flows over the heat pipes. When the temperature of the flue gas exceeds 30°C, the heat pipes become active and transfer heat to the right side automatically. At this point, the left side of the heat pipes absorbs heat, and the temperature of the hot flue gas drops as it passes through these heat pipes; the heat is then absorbed by the heat pipes and transferred to the right side. At room temperature, clean air (water or other media), driven by a blower, flows in the opposite direction along the right channel to wash over the heat pipe; at this point, heat is released on the right side of the heat pipe, heating the clean air (water or other media). The temperature of the air rises as it passes through the heat pipe. A waste heat recovery device composed of several heat pipes is installed at the boiler’s exhaust outlet; it absorbs the heat from the flue gases and transfers it rapidly to the other end, thereby reducing the exhaust temperature to near the dew point and minimizing heat loss. The heated clean air can be used to dry materials or fed back into the boiler for reuse. Improve the thermal efficiency of boilers and industrial furnaces, reduce fuel consumption, and achieve energy savings. 　 6 f: L5 x7 F$ h/ j) b! E" g In the design and manufacture of industrial fuel, gas, and coal-fired boilers, in order to prevent corrosion and ash deposition on the heated surfaces at the back of the boiler, the exhaust gas temperature under standard conditions is generally not lower than 180°C, and can reach up to 250°C. The emission of hot flue gases not only results in significant waste of thermal energy but also causes environmental pollution. 　) Q% L' U' \8 t7 B The heat pipe waste heat recovery unit can recover the heat from flue gas; the recovered heat can be used to heat water for use as make-up water in boilers and for domestic purposes, or to heat air for use as combustion air in boilers or for drying materials. It saves fuel costs, reduces production expenses, cuts exhaust emissions, and achieves both energy conservation and environmental protection. The investment in renovation pays off within 3-10 months, yielding significant economic benefits. We now often use this method for boiler modifications. Success.

Based on practical experience, the most effective measures include: 1. Installing a steam recovery unit; 2. Changing the coal feeding system to enable layered combustion; 3. Modifying the economizer (water-wrapped type); 4. Ensuring proper insulation; 5. Using variable frequency drives for water supply and fans; 6. Installing steam flow meters to evaluate the operator’s performance; 7. Checking the condition of the boiler, such as the presence of scale and the condition of the furnace arch