Steam quality is an important indicator for measuring the overall quality of a gas-fired steam boiler. This is because many companies purchase gas-fired steam boilers directly using steam. If the steam quality is not high, it is likely to affect the entire production of the project. Process and the quality of the final manufactured item. So, how do enterprise users choose a gas-fired steam boiler with good enough steam quality?

1. Cleanliness of gas steam boiler
       There may be rust and carbonate deposits in the steam pipeline, and there may be residual welding slag and sealing material fragments during installation. These impurities will cause blockage and damage to valves and equipment, and will also increase pipeline wear. The way to improve cleanliness is to equip gas steam boilers with pipe filters to deal with these impurities in real time.

2.Dryness of gas steam boiler
       Factors such as improper water treatment for gas-steam boiler water treatment, irrational boiler level control, and excessively high peak loads for a short period of time will cause the phenomenon of co-transpiration of the boiler, causing the boiler outlet to carry boiler water. When the steam moves in the pipe, the heat dissipation of the pipe will cause a part of the steam to condense, adding condensed water in the pipe. Adding a steam-water separator is a useful way to improve steam dryness. An efficient steam-water separator can improve steam dryness to 98%.

3.Purity of gas steam boiler
       There will be air in the steam system. This is because the steam generated in the boiler still inevitably contains a small amount of air. In addition, there will also be air when the pipes and equipment are started. When the system and equipment are stopped, the air is sucked in due to the internal vacuum.

Air has a low thermal conductivity and is a poor conductor of heating. The steam system contains air, which will reduce the production capacity of steam equipment, and also increase the corrosion of pipelines, valves and equipment. The most useful way to eliminate non-condensable gases such as air in the steam system and improve the purity of the steam is to install an automatic air exhaust device in the system.

From a professional perspective, the capacity of a steam boiler is called "tonnage," and the capacity of a hot water boiler is called "power." Learn to switch between power and tonnage, you can quickly and easily understand the parameters of the boiler.

For hot water boilers, the boiler power is expressed in MW (1MW = 1000kW) or million kcal / hour (ten thousand kcal / h).

For a steam boiler, its power is also called the evaporation capacity, which is the amount of water converted into steam per hour: ton / hour (T / h) or kilogram / hour (kg / h). Of course, it can also be expressed in MW or KW.

In China, the correspondence between evaporation and power is:
       1T / h = 1000kg / h = 0.7MW = 720kW = 600 thousand kcal / h = 600Mcal / h.
       Units of power are also horsepower (Hp) and boiler horsepower (BHp).
       1Hp = 0.745kw, 1BHp = 9.81kw

In some European and American regions, the steam boiler evaporation capacity is often marked with "at 212", which means that its evaporation capacity refers to the evaporation of 212 degrees Fahrenheit of water to 212 degrees Fahrenheit, which means that the water evaporation at 100 ° C Amount of steam at 100 ° C. In this way, 1kg of evaporation is equivalent to 540kcal of heat. We call it "equivalent evaporation", that is: 1T / h = 540,000 kcal / h. It can also be deduced from this that the relationship between boiler horsepower and "equivalent evaporation" is: 1BHp = 15.62kg / h.

In boiler equipment, these parameters also have corresponding conversion relationships.
       1 ton / hour (t / h) ≈ 60 × 104 kilocalories (kcal) / hour (kcal / h) ≈ 0.7 megawatt (MW) ≈ 720K kilowatt (KW)
       2. Boiler evaporation and boiler horsepower 1 ton / hour (t / h) ≈ 71.1 boiler horsepower (BHP);
       3. Boiler pressure engineering unit and international unit of measurement 1 MPa (Mpa) ≈ 10 kgf / cm2 (kgf / cm2);
       4. Megapascals and Pascals 1 Megapascal (Mpa) = 106 Pa (pa) 1 Pa (pa) = 0.01mbar (mbar) ≈ 10-5 kgf / cm² (engineering atmospheric pressure) (kgf / cm2) 1 pa (Pa) ≈0.1 millimeter water column (mmH2O);
       5. Force and gravity 1 kgf (kgf) = 9.81 Newton (N);
       6. Calories 1 kcal (kcal) = 4.187 kilojoules (KJ);
       7. Volume (volume) 1 cubic meter (m3) = 1000 liters (L) 1 liter (L) = 1000 milliliters (ML).

Industrial boilers are generally steam boilers used for power generation or gas supply. For example, in a chemical fertilizer plant, steam can be vaporized, coal is used as raw materials, and synthetic fertilizers. This is a typical industrial boiler. As an important thermal power equipment, industrial boilers have propped up the sky of manufacturing.

According to different structures, industrial boilers can be divided into three types: fire tube type, fire tube type and water tube type.

1.Fire tube boiler
       It was an early boiler. There were only one or two fire pots in the pot for heating the pot water. There were burning devices in the fire pots. Due to the low thermal efficiency, large volume and steel consumption of fire tube boilers, production has basically ceased since the 1960s.

2.Fire tube boiler
       In addition to a fire tube, a number of smoke pipes are installed in a vertical or horizontal pot shell. The high-temperature flue gas generated by the combustion of fuel in the combustion chamber passes through these smoke pipes to heat the boiler water, and then is discharged into the chimney. Compared with the fire tube boiler, due to the large number of smoke pipes, the heating area is increased, the exhaust temperature is lower, the thermal efficiency is higher, the steel consumption and the boiler volume are smaller. The evaporation capacity of fire tube boilers is generally not more than 15 tons / hour, the working pressure is generally not more than 1.6 MPa, the thermal efficiency of coal-fired boilers is generally about 70%, and the more intelligent fuel gas boilers, the thermal efficiency can reach 85% -98 %about.

3.Water tube boiler
       Water tube boilers are mostly used in industrial industries with large capacity and high pressure requirements. They are divided into natural circulation and once-through boilers according to the different circulation methods. Natural circulation water tube boilers have single and double drums. After the convection tube bundle of the double-boiler water tube boiler, an energy saver is generally provided, and an air preheater is sometimes provided to reduce the exhaust temperature. The efficiency can reach 80% when burning coal, and it will be higher if it is fuel gas. There is no drum in the once-through industrial boiler, and the heating surface is composed of a tube coiled on the inner wall of the furnace and a convection tube bundle at the back. Feed water enters from one end of the pipe and steam exits from the other. Once-through industrial boilers are small in size and generally have a steam-water separator and an automatic control device.

Heating and heating boilers belong to the category of civilian life boilers. With the improvement of people's safety awareness and the popularization of centralized heating, since 2000, buildings have been heated with hot water as the heat medium, and steam boilers are not allowed. Generally speaking, the heating boilers we refer to are hot water boilers.

There are many types of heating and heating boilers, and their classification is mainly divided according to the type of fuel. They can be divided into electric heating boilers, oil heating boilers, gas heating boilers, coal-fired heating boilers, and biomass heating boilers. Oil-fired heating boilers and gas-fired heating boilers are the more common types of heating boilers.

Everyone needs to determine the boiler parameters according to their own needs. It must not be too small and the boiler supply cannot meet their own needs, and it must not be too large and cause waste of resources. Zhengzhou Fangkuai Boiler Co., Ltd. sorts out methods for determining parameters of steam boilers and hot water boilers for some industries that use boilers widely.

Most of the boilers required by industrial and mining enterprises for production are steam boilers, and the steam output by the boilers is mostly used in production that requires a certain amount of heat to meet the production process requirements, such as textile printing and dyeing, food sugar, rubber paper, Petrochemical and other industries. Therefore, according to the requirements of the production process, determine the saturated steam parameters of the boiler, and accurately determine the parameters of the saturated steam to ensure that the temperature required for production is constant.

Generally speaking, the pressure of the boiler is always higher than the saturated steam pressure required for production. The reason is to overcome the pressure loss in the pipeline or pipe network. Many users have also found that the pressure on the boiler nameplate is much greater than the pressure required for production. For example, many users have purchased a 13-pressure boiler, but in fact only use 5 gauge pressure or 6 gauge pressure operating pressure. Operating at such low pressures has an adverse effect on steam quality. Because the pressure decreases, the specific volume of the steam increases, and the flow velocity at the outlet greatly increases, which causes the phenomenon of steam carrying water to rise. The pressure required for general production plus the pressure drop required to overcome all pipeline resistance, plus a pressure margin of 25% to 30% is sufficient.

For hot water boilers required for heating and heating, the commonly used temperature parameters are the supply and return water temperatures of 95/70 ° C. At present, there are three types of domestic urban heating; thermal power plants, regional boiler rooms, and scattered small-capacity boiler rooms. The former two are centralized heating, and the district boiler room heating is the development direction. At present, the majority are scattered small capacity boiler rooms. For district heating, the high temperature hot water boiler, supply and return water temperatures will develop 130/70 parameters. At present, three grades of 95/70, 115/70, and 130/70 are available for selection in hot water boiler products. The operating pressure of hot water boilers in actual use is mostly lower than the design pressure, which is mainly limited by the original pipe network system.

How to determine the capacity of a boiler when choosing an industrial boiler is an important issue. Generally speaking, the output or capacity of the boiler should be determined according to the steam consumption or heating area in the production process and the heat supply required for domestic hot water. First of all, the user must find out the total load range; second is the peak situation, including the peak load duration, the frequency of the peak, that is, the periodicity of the peak, such as the number of monthly peaks, weekly, monthly, and winter and summer in a year The difference. After understanding the demand and peak of the boiler load, you can consider the equipment capacity and number of units. In the selection, we must also consider the problem of the amount of emergency shutdown.

The reserve capacity generally refers to a standby boiler. The standby boiler does not need to be started when the original boiler is working normally. If the original boiler fails and is shut down, the standby boiler must be started immediately. This needs to be determined according to the importance of the user itself. If the continuity requirements in production and use are high, the issue of standby equipment must be carefully considered.

The economic load of a general boiler is more than 75% of the rated load, so the actual load of the boiler in use should always be more than 50% of the rated load of the unit itself, which means that the equipment provided by the manufacturer is between 50% and 100% of the rated output. It should be stable and efficient. In the past, users often purchased too much margin for safety reasons, which caused the equipment to operate under low load for a long time, which was very uneconomical. Generally, for boiler rooms with a total capacity of 8 tons / hour or a thermal power of more than 6 megawatts (MW), three units are more suitable. Due to the difference between winter and summer, you can choose different output equipment. However, it is more convenient and economical to choose the same equipment for new boiler rooms in terms of operation, maintenance, and management. Such auxiliary arrangement of auxiliary equipment of boiler room can be reasonably arranged. If you consider the high and low peaks and the big differences between winter and summer, you can also choose two big and one small equipment. According to the needs of the new boiler room, you can choose more equipment than three, but it should not be too much. Instead of using many equipment, choose a higher capacity equipment. In the current situation of domestic equipment quality, it is necessary to consider standby units.

Enabling the operation of energy saving and emission reduction of industrial boilers can save a large amount of investment costs for enterprise units, and it can also save the tedious inspection of environmental protection departments.

For industrial boilers, whether they can achieve energy conservation and emission reduction depends on these measures. Zhengzhou Fangkuai Boiler Company will come to explain one by one for you.

1. Reconstruction of fuel supply device
       For oil-fired gas boilers, it is necessary to effectively control the ratio of fuel and air to achieve sufficient combustion. There should be neither too much nor too little fuel.

2.Transformation of combustion system
       The traditional industrial boiler combustion method is diffusion combustion. Such a combustion method is likely to cause uneven combustion temperature inside the boiler furnace, which may easily cause insufficient combustion of fuel, resulting in waste of fuel energy. Zhengzhou Fangkuai Boiler Co., Ltd. changed the combustion system of the industrial boiler to full premixed combustion. This type of combustion uses fuel and air to be mixed in advance, and then close to the combustion device, which can ensure that the temperature in the furnace is uniform throughout and avoid fuel combustion. Non-uniformity occurs.

3. Rebuild the overall structure of the boiler
       Many industrial boilers do not adopt a reasonable design structure when they are manufactured, which will also lead to a reduction in the thermal efficiency of the boiler and ultimately fail to achieve the purpose of energy saving.

4. Reconstruction of boiler auxiliary machine
       The frequency conversion combustion technology can be used to achieve dynamic and intelligent combustion of the boiler, which not only saves the trouble of the boiler worker every time adding fuel, but also makes the boiler and fuel delivery more compatible.

5. The automatic control system is adopted to adjust the output heat of the boiler in real time to achieve the purpose of energy saving.

6.Recovery condensate from boiler operation
       The industrial boiler can increase the operating efficiency by more than 10% after adding condensing technology, which is very energy efficient. However, such a boiler will also generate a lot of condensed water after operation. If the user does not use this part of condensed water, it will also cause energy waste. The temperature of the condensed water is generally around 100 ° C, which is very low compared to the boiler temperature, but there is also a lot of heat. You can recover this part of the condensed water and participate in the boiler for reuse.

7.Boiler replacement, replacement of old boilers with new boilers
       If the operation efficiency of the original boiler is very low, or the pollutants emitted are seriously exceeded, and the service life is long, we do not recommend that you continue to use or rebuild the original boiler. After all, the cost of such a boiler reconstruction It is also very high, and it is better to directly purchase a new fuel-gas industrial boiler that has high energy efficiency and low nitrogen emissions.

Performing a water pressure test before the boiler is officially started can grasp the problems existing in the boiler early and deal with them in a timely manner. Take oil-fired gas boilers for example.

The hydraulic pressure test of oil-fired gas boilers is generally divided into a hydraulic pressure test and a super-hydraulic test of rated working pressure. The overpressure test pressure of the boiler body is 1.25 times of the rated working pressure of the boiler shell or the rated pressure plus 0.4 MPa.

If one of the following situations occurs, our oil-fired gas boiler also needs to perform an overpressure water pressure test.
       1. Before the newly installed boiler starts trial operation;
       2. After the boiler's pressure parts have undergone major transformation or replacement;
       3. The boiler in operation is performed every six years (combined with overhaul).

If one of the following situations occurs, our oil-fired gas boiler needs to perform a working pressure and hydraulic test.
       1. Generally, after large or small repairs or rush repairs, the hydraulic pressure test of the working pressure is performed after the repairs;
       2. If the furnace is shut down for more than 30 days, a hydraulic pressure test of working pressure must be performed before ignition.

Previously we said that it was better to perform a hydraulic test for the sake of safety. However, whether it is a steam boiler or a hot water boiler, after the boiler is installed, a hydraulic pressure test (that is, water pressure) must be performed. After long-distance transportation, loading, unloading, and installation, collision and damage are unavoidable. Boiler defects can be found through hydraulic tests, and appropriate measures can be taken in time to ensure the safe operation of the boiler.

Full water is a certain danger for the steam boiler in operation. Once the steam boiler is full of water, the output steam will bring a large amount of water, or the water hammer in the steam pipeline will occur. To reduce the steam quality, it will also affect the normal gas supply of the boiler. In addition, if the consequences are very serious, it is the fouling of the superheater in the steam boiler, which causes damage to the boiler. If the boiler operators do not find and solve in time, the boiler is likely to have more dangerous accidents. So, when the steam boiler is full of water, how do you quickly solve it? Listen to the technical lecturer from Zhengzhou FANGKUAI Boiler Co., Ltd. to explain in detail for everyone, how to deal with steam boilers full of water quickly to minimize damage.

In order to keep the steam boiler away from water-filled accidents, we must first start from Sheung Shui.

For steam boilers, the hardness of the feed water is mainly required, which should be within 0.03 mmol / liter. In addition, in order to avoid the full water accident of the steam boiler, the standards on the superheater must be strictly in accordance with the requirements, etc., to carry out specific operations in this regard.

In a steam boiler, if there is a superheater, it can produce dry steam. However, if the condition inside the boiler deteriorates, it can only be saturated with steam.

For the various situations that the steam boiler will encounter during operation, the technicians of Fangkuai Boiler just gave a brief introduction to everyone from the situation of full water. I hope that it can help everyone to improve their knowledge and understanding of the steam boiler. We can apply what we have learned from time to time to avoid safety accidents in the boiler.

It is believed that many user units need to use boilers as a source of heat to drive the demand for heat production in the factory or in the living. But if you want to make the boiler work better for us, you need to pay special attention to the installation problem. Because even if the boiler is better, if there is any problem in the installation, the operating efficiency of the boiler will be greatly reduced.

There are a lot of issues that we need to consider before installing the boiler. The first is the consideration of the installation location. Because the boiler is used to provide thermal energy, the surface temperature is very high, so it should be avoided to contact the human body when installing the boiler. The choice of the installation location should be as far as possible at the corner or on the side, so as not to hinder the passage of people, this is the first consideration when installing.

Another problem to be noticed is ventilation, because the boiler will generate a lot of fumes during use. Even if each boiler has a special exhaust facility, it is still necessary to pay attention to ventilation during installation. Attention to ventilation has two advantages, the first is to facilitate the emission of smoke, the second is to maintain the temperature inside the boiler room, so that the temperature is too high, making people feel uncomfortable.

The horizontal steam boiler is a relatively classic type in the current boiler market. It adopts the horizontal design structure. The arched tube plate and the threaded pipe form a drum. The heat transfer efficiency is high, the pressure is fast, the output is sufficient, and the load is overloaded. Strong ability, not easy to accumulate in the pipe.

The welding joint of the horizontal steam boiler is treated by large-scale machining and special processing in the high-temperature zone tube bundle. The manufacturer will also carry out flaw detection treatment in the later stage to ensure that the weld is 100% qualified before the boiler can be shipped, which greatly guarantees the boiler. safety.

The horizontal steam boiler has a compact structure, small size and size, saves capital investment, and is easy to install. It can be operated by connecting valves, water and electricity and pipelines. Stable operation, convenient adjustment, unique anti-leakage design, long sealing time.

The dust, sulfur and nitrogen oxides contained in the flue gas of horizontal steam boilers are all pollutants that pollute the atmosphere. When not purified, the emission index can reach several times to several tens of times of the environmental protection regulations. Measures to control the discharge of these substances include pre-combustion treatment, improved combustion technology, dust removal, desulfurization and denitrification. The use of high chimneys only reduces the concentration of pollutants in the atmosphere near the chimney.

In the current boiler market, there are more and more types of gas-fired boilers using energy-saving technologies, and condensation technology is one of them. By adding a condenser at the end of the boiler, a large amount of latent heat is released when the high-temperature flue gas passes through the condenser, and is supplied to the boiler for reuse.

Condensed water refers to liquid water formed by water vapor (ie, gaseous water) during condensation, which is a physical change. Today, Fangfang Boiler will unveil the treatment of condensate for you!

1. There are two main reasons why gas boilers produce flue gas condensation water.
       (1) The water vapor in the flue gas condenses into water when it is below the dew point temperature;
       (2) The boiler has high thermal efficiency and low exhaust gas temperature. The exhaust temperature of the boiler under the rated load is slightly higher than the dew point temperature of the flue gas. Under the condition of long-term operation with low load, the flue gas temperature is lower than the flue gas dew point temperature, and condensed water will flow out from the tail heating surface of the boiler. , the boiler is discharged from the rear smoke box.

2. What are the components of gas boiler flue gas condensate?
       The gas boiler generates condensed water during operation. The main components of the condensed water include: water produced by natural gas combustion, sulfur oxides formed by combustion of sulfur in natural gas impurities, acidic substances formed in water, and nitrogen in the air under high temperature conditions. The nitrogen oxides formed by the oxygen in the air are dissolved in the acidic substances generated by the water.

3. There are too many condensed water in the gas boiler. How to deal with it?
       When the gas boiler is in operation, especially when the cold furnace is started, the flue gas condensed water is often generated at the heating surface of the boiler tail and the rear smoke box, so that the furnace worker mistakenly believes that the boiler leaks.
       The condensed water generated by the gas boiler during operation should be discharged out of the boiler in time, because if the condensed water accumulates too much, it will affect the normal operation of the boiler, which will cause water leakage at the connection between the rear smoke box door cover and the rear smoke box flange.
       Specific measures include:
       (1) The boiler is provided with a condensate drain at the rear smoke box
       In order to enable the condensed water to be discharged in time, the discharge port is generally not provided with a valve, and a water seal should be provided to prevent the flue gas from escaping from the tube.
       (2) Smoke box outlet setting takeover
       After the boiler flue gas exits the smoke box and enters the chimney, since the heat dissipation of the chimney is still cooling, the water vapor in the flue gas is still condensed on the chimney wall, forming small water droplets flowing down the chimney wall, so it should be in the smoke box. The outlet is set to allow the condensate to drain into the trench or any drainage system.
       Excessive condensate of gas boiler flue gas should cause concern. Although condensed water production is unavoidable, excessive condensed water is generated, which will inevitably affect the safe operation of the boiler.

4. Does the flue gas condensate of the gas boiler have any pollution problems? Do you need special treatment? According to the composition analysis of the condensed water, we can know that the condensed water is acidic. The pH value of condensed water is mainly related to the sulfur content of natural gas. At present, domestic natural gas is mainly from four atmospheric fields, and the sulfur content is unknown. If you are interested, you can buy some PH test paper to measure the PH value of the boiler condensate.
       In general, the condensate pH of a cast aluminum heat exchanger is slightly higher than that of stainless steel (equivalent conditions).
       But although the condensate has a certain acidity, it has little effect on the environment. Do not believe that the condensate is collected in a bucket, added with alkaline substances and then poured into the sewer.

Because the condensate is somewhat acidic, it is diluted very lightly after entering the sewer system, and its effect is minimal. Moreover, today's residential sewers are made of plastic pipes, and even condensed water that has not been diluted will not affect the pipeline.

So we can ignore the environmental impact of this condensate. There is no need for special handling.

Controlling boiler operating costs is a particular concern for units using gas boilers. In the operation of gas boilers, enterprise users can control the production cost by improving the combustion efficiency and thermal efficiency of the boiler. One of the key factors is that we must choose a powerful boiler manufacturer to purchase a boiler with excellent performance and advanced technology, and then reduce production by reducing the fuel consumption of the gas boiler without affecting the use effect. The purpose of the cost. The following are the recommendations given by the engineers of FANGKUAI Boiler.

1. Flue gas condensation heat recovery system: This system mainly reduces the heat generated by the gas boiler during the smoke exhaustion, and reduces the gas consumption without affecting the boiler's own thermal efficiency.

2. Climate compensation system: This system is adjusted according to indoor and outdoor temperature changes, so that the overall heating, heat release and building of the gas boiler are consistent, preventing excessive temperature difference between indoor and outdoor.

3. Heating system hydraulic balance: the average heating quality of all users, using this system, can directly save about 10% of energy.

4. Heating centralized control system: install the number of boilers according to the required heat load, and evenly distribute the heat load between the gas boilers, so that all boilers can reach the optimal state. The technology in this area is not mature enough in China. If you want better results, you can use imported boilers.

As a manufacturer specializing in the production of gas boilers and electric boilers, FANGKUAI Boiler has gone through more than 20 years of development. The energy-saving gas-fired boiler produced by the company adopts the technology of first pre-expansion and then full-welding, and finally re-expanding, which not only prevents the pipe gap corrosion, but also enhances the welding strength; uses a high heat transfer coefficient thread pipe to enhance the convective heat transfer effect. Reduce the exhaust gas temperature and improve the thermal efficiency of the boiler. With the industry-leading gas boiler products and perfect after-sales service, FangFeng Boiler is recognized and trusted by many gas boiler users.

If you have any requirements for gas boilers, please call the National Express 24-hour service telephone number 0371-60922096 directly, we will arrange professional engineers to answer your questions in the first time.