Biomass boiler

                                                                      Biomass boiler

The material boiler is a kind of boiler, that is, the boiler using biomass energy as fuel is called biomass boiler, which is divided into biomass steam boiler, biomass hot water boiler, biomass hot air furnace, biomass heat transfer oil furnace, vertical biomass boiler, horizontal biomass boiler, etc.
Classification of biomass boilers: horizontal biomass boilers, vertical biomass boilers. Biomass gas heat transfer oil furnace, biomass steam boiler, biomass hot water boiler, biomass heat transfer oil furnace.

Boiler features
The boiler adopts the most suitable combustion equipment for biomass fuel combustion ---- reciprocating grate. In the structural design of the boiler, compared with the traditional boiler, the furnace space is larger, and the secondary air is arranged reasonably, which is conducive to the full combustion of a large amount of volatile released instantaneously during the combustion of biomass fuel.
The boiler can be equipped with oil (gas) ignition burner to realize ignition automation. The feeding, combustion, slag removal, water supply and ignition of the boiler can be controlled automatically, which is very convenient to operate. The boiler is equipped with an automatic ash removal device, which can timely remove the accumulated ash on the heating surface of the boiler and ensure the efficient and stable operation of the boiler. Economizers are arranged at the tail of the boiler, and air preheaters can also be arranged according to the needs of users. Compared with the traditional boiler, the boiler has higher efficiency and lower exhaust gas temperature.
High efficiency thermal insulation material is adopted, the boiler surface temperature is low, and the heat dissipation loss can be ignored. It is produced in strict accordance with Chinese national specifications and standards, and all pressure parts are made of high-quality boiler steel. Each boiler shall undergo strict inspection and test before leaving the factory, including hydrostatic test and X-ray inspection. There are manholes, inspection doors, fire observation holes, etc., which are very convenient for maintenance. Biomass boilers are characterized by energy saving, environmental protection and easy installation and use.
Fuel supply
The fuel of the boiler is BMF fuel. The fuel is sent to the furnace top silo by the conveyor, and then sent to the furnace by the screw feeder, which is evenly scattered on the grate.
Combustion process
The fuel is sent into the furnace by the screw feeder, where it is gradually preheated, dried, ignited and burned due to the action of high-temperature flue gas and primary air. During this process, a large amount of volatile matter is released, and the combustion is intense. The generated high-temperature flue gas washes the main heating surface of the boiler, enters the economizer and air preheater of the heating surface at the tail of the boiler, then enters the dust collector, and finally is discharged into the atmosphere through the chimney. The UN gasified fuel moves towards the rear of the grate until it is burnt out, and finally a small amount of ash and slag will fall into the slag removal port behind the grate.
Environmental emission
The ash produced by BMF combustion accounts for about 1.5% of the fuel. In order to facilitate ash discharge, a spiral slag extractor is arranged at the rear of the boiler to realize continuous ash removal. The flue at the tail of the boiler is equipped with a dust collector to ensure that the smoke emission meets the environmental protection requirements.
Boiler efficiency
Generally, the efficiency of biomass boilers is more than 80%. The larger the boiler model, the more sufficient the combustion, the higher the efficiency of the boiler. The highest reached 88.3%, 15% higher than the average efficiency of coal-fired boilers.

Constant pressure mode
Scope: in heating system
Constant pressure mode in biomass boiler heating system: in the high-temperature hot water supply system, since the water temperature is higher than the saturation temperature of atmospheric water, the pressure in the system should adhere to the saturation pressure higher than the corresponding water supply temperature, so as to avoid hot water vaporization and water impact. Water is an irrepressible fluid, which will depressurize in case of leakage; On the contrary, water heating will shrink the volume. If the pressure cannot be stabilized, the equipment in the heating system will be destroyed. Therefore, in order to avoid pressure reduction, vaporization, contraction and pressure rise, the high-temperature hot water system must stabilize the pressure in the system, which is called constant pressure. The pressure setting methods of hot water heating system are as follows:
1) Elevated water tank constant pressure mode
The constant pressure point of this method is set at the inlet of the hot water circulating pump or on the return main line. It is only an elevated water tank. It has simple structure, stable and reliable operation, can stabilize the system pressure, and can meet the overflow and make-up requirements of the system network. In this system, the height of the water tank device must meet the requirement that the highest point in the system is not vaporized. Therefore, the device position is high. This constant pressure mode is applicable to low-temperature water heating systems with small heating range.
2) The constant pressure mode of make-up water pump is adopted
When the pressure of the heating system is high, the high-grade water tank can not guarantee the pressure required by the system. At this time, the constant pressure mode of the make-up water pump should be adopted. This constant pressure mode was widely used in the Soviet hot water boiler heating system. The constant pressure of make-up water pump can be divided into two modes: continuous water supply constant pressure and continuous water supply constant pressure. The constant pressure installation of the biomass boiler consists of a make-up water tank, a make-up water pump, a pressure regulator, etc. When the system operates normally, the pressure regulator regulates the make-up water pump to continuously make up water and make it comply with the leakage of the system, so as to maintain the stability of the system pressure. When the circulating water pump stops, the stop valve in front of the pressure regulator can be closed. The make-up water pump still makes up water continuously to maintain the static pressure required by the system. This constant pressure mode does not need to shrink the water tank, so the equipment cost is low. In addition, the make-up water pump makes up water and sets the pressure. The water pump power is small and the operation cost is small. Therefore, this method is widely used in hot water heating system in China. The biggest drawback of this constant pressure mode is that if the system suddenly loses power, the make-up water pump will lose its constant pressure function. In order to avoid water shortage and vaporization of the boiler at this time, the system adopts the pressure water feeding auxiliary installation. When the circulating water pump is running, due to the water feeding auxiliary installation, the circulating water will not be poured back into the pressure rising system. When the circulating water pump and make-up water pump are shut down due to sudden power failure, the pressure feed water system will be put into operation immediately, the check valve will be opened automatically, and the pressure water will flow through the hot water boiler and be discharged from the gas collecting tank, thus preventing the boiler water from vaporizing due to the waste heat in the boiler room. At the same time, the main valve of the heat supply and return pipe should be closed to isolate the heat source from the heat supply network. The continuous water supply and constant pressure of the biomass boiler make-up water pump is controlled by the electric contact pressure gauge. The inlet pressure of the circulating water pump can be maintained within a certain range. When the pressure is lower than this range, the electric contact pressure gauge acts and connects the motor circuit of the make-up water pump. The make-up water pump operates and makes up water. When the inlet pressure of the hot water circulating pump rises and exceeds a certain range, the pressure gauge of the hot water boiler is to cut off the power supply of the make-up water pump, The make-up water pump stopped. With this reciprocating action, the make-up water pump continuously replenishes water and maintains the system pressure within a certain range. In this way, the constant pressure mode of the system saves electric energy compared with the continuous water replenishment mode, but its conditioning and constant pressure quality are worse than the continuous water replenishment mode. There are also defects such as large pressure fluctuation, frequent action of pressure gauge contacts and easy damage.
Fold and edit boiler environmental protection in this section
At present, there are about 500000 industrial boilers in China, and the annual coal consumption is about 1/3 of the total national coal consumption. The environmental pollution caused by coal-fired industrial boilers is very serious, and a large number of industrial boilers must be replaced with clean energy. According to the conditions of biomass resources in China, the use of agricultural and forestry residues as boiler fuel is environmentally friendly and renewable. The research on biomass combustion technology of industrial boilers and the development of biomass fuel boilers are of positive significance for saving conventional energy, optimizing China's energy structure and reducing environmental pollution.
Due to the restrictions of power, natural gas supply and gas pipelines, it is impossible to change all coal-fired boilers in China into electric or gas-fired boilers. The low price and low operating cost of biomass boilers make it easier for users to accept and promote, which just fills this gap. Biomass pellet fuel is made of straw, rice straw, fuel wood, sawdust, peanut shell, melon seed shell, beet meal, bark and other waste crops by crushing, mixing, extrusion and drying, and finally made into granular fuel. In China, its raw materials are widely distributed and its processing technology is advanced. Biomass pellet is known as green coal and is a kind of clean energy. As the fuel of the boiler, it has long combustion time, high temperature in the intensified combustion furnace, and is economical. At the same time, it has no pollution to the environment. It has zero emission of CO and so. It is a renewable energy, which can be recycled and can replace wood, coal and natural gas. The operating cost is only half of that of gas. A large number of agricultural raw materials in China provide a strong material guarantee for the promotion of biomass boilers. It can not only solve the problem of straw burning by farmers, but also make full use of resources. The burned ash is a very good fertilizer, which is a move to kill many birds with one stone. Hengyang Dacheng believes that biomass boilers will reduce PM2.5 emissions, effectively promote the development of environmental protection, and are an important part of China's new energy strategy.
The air emission standard for biomass boilers shall strictly comply with the air pollutant emission standard for boilers formulated by the national environmental protection department
type
Biomass boilers biomass boilers can be roughly divided into two types according to their uses: one is biomass thermal boilers, and the other is biomass electric boilers.
In fact, the principles of the two are basically the same. Both of them obtain energy by burning biomass fuel, but the first directly obtains heat energy, and the second converts heat energy into electric energy. Of the two types of boilers, the first one is the most widely used one with mature technology.
If we continue to subdivide, the first boiler, biomass heat boiler, can also be divided into three categories:
Class I: small biomass heat boiler. The boiler uses solidified or gasified biomass fuel to provide heat energy in the form of hot water. Its advantages are small size, simple structure and low price; The disadvantage is that the energy consumption is large, the fuel consumption is large, and the heat energy supply is low, which can not meet the needs of users with large heat energy demand. The goal of this boiler is to supply heating and domestic hot water for a single rural household.
Class II: medium biomass heat boiler. Such boilers mainly use solidified biomass fuel to provide hot water or steam. Its advantages are that the technology is mature, the energy loss is small, and the heat energy supply capacity is strong; The disadvantage is that some boiler fuels are coking and the supporting design is unreasonable.
Class III: large biomass heat boiler. This kind of boiler has no actual products, mainly because the existing technology is not perfect, and the national policy for biomass to replace coal is not perfect. Therefore, it only stays in the concept. What it emphasizes is a kind of heat energy project with centralized management and control. The boiler is only one of the equipment to ensure the normal operation of the whole biomass heat energy project. Therefore, it has high requirements for fuel, combustion technology, supporting technology and relevant policies.
classification system
Feeding system
The feeding system consists of a silo, a vibrating feeder, a screw feeder, a screw feeding pipe and other components. BMF fuel processed in the factory is transferred to the bunker by belt conveyor, and then BMF fuel in the bunker is fed to the burner for combustion by screw feeder. In order to ensure the stability of continuous feeding and material conveying, a vibrating feeder is connected between the silo and the screw feeder.
Folding combustion system
The combustion system is composed of burner, fan, igniter and other components. Biomass fuel first has a preheating process in the burner, and then the fuel is delivered to the furnace for combustion through the fan. BMF fuel contains high volatile. When the temperature in the furnace reaches its volatile emission temperature, the fuel can be ignited and burned quickly when the igniter is started under the condition of air supply. The temperature control of the burner is based on the internal temperature of the furnace, which is related to the amount of gas supplied during fuel gasification. The adjustment of boiler load is controlled by the adjustment of feeding amount. After combustion, the flue gas enters the convection flue through the furnace for heat exchange, then enters the dust collector for purification, and finally discharges to complete the whole combustion and heat transfer process.
Soot blowing system
The boiler is equipped with a full-automatic soot blowing device, which can regularly purge the furnace and flue gas pipe, so as to ensure that there is no dust on the flue gas pipe surface, so as to realize the safe and efficient operation of the boiler.
Smoke and air system
Air supply system: the boiler air supply system is integrated with the burner, and the air is sent to the furnace through the burner through the blower to achieve the function of fuel delivery and combustion support.
Induced draft and dust removal system: under the action of induced draft fan, the high-temperature flue gas generated after combustion enters the dust collector for purification through convection heat exchange in the flue pipe, and finally is discharged from the chimney through the induced draft fan.
Automatic control system
The control system (see the figure below) adopts high brightness and full Chinese display, with the famous brand PLC control system as the central control unit; Exchange information with boiler users through man-machine dialogue to realize full-automatic operation of BMF boiler.
Fuel analysis
1. The sulfur content of biomass fuel is mostly less than 0.2%. When it is extinguished, gas desulfurization installation is not required, which reduces the cost and is conducive to environmental maintenance;
2. The biomass boiler extinguishing equipment can be used to reduce the biomass resources in a large scale, make them harmless and apply them as resources as soon as possible, and the cost is low. Therefore, the biomass direct extinguishing technology has good economy and development potential.
3. The carbon dioxide released by biomass extinction is roughly equivalent to the carbon dioxide absorbed by its growth through photocatalysis, so it can be regarded as zero emission of carbon dioxide, which helps to alleviate the greenhouse effect;
4. The extinguishment products of biomass are widely used, and ash can be comprehensively applied;
advantage
Biomass boilers need green new energy. Compared with other boilers, biomass boilers mainly have the following four advantages:
1。 A multi-purpose stove can be used for cooking, boiling water and bathing while heating.
2。 Super conversion system, low starting heat transfer temperature and fast heat transfer speed.
3。 Low installation cost and safe heating: the equipment is universal without changing the original heating equipment. Pipes and radiators are universal. Water circulation is used to achieve a wide range of sources of heating materials, which can never be exhausted and can be taken anywhere (such as chaff, corn stalk, rice straw and wheat)
4。 Safety and environmental protection: low working pressure, cooking, boiling water, bathing, heating, etc. at the same time, it is also suitable for boiler burning, greenhouse heating, large-area heating, small and medium-sized hotels. It is not limited by seasons and can be used all year round.
Extinction process
Because the fuel characteristics of biomass boilers are different from fossil fuels, the extinction mechanism of biomass fuels in the extinction process is caused. The reaction speed and the composition of extinction products are also quite different from fossil fuels, showing different extinction characteristics from fossil fuels. As shown in the above figure, the extinction process of biomass fuel is mainly divided into two independent stages: volatile emission and extinction. The extinction and burnout of coke, the former accounting for about 10% of the extinction time and the latter accounting for 90%. The detailed extinction process is as follows: after the fuel is sent into the extinction chamber, the fuel is heated and moisture is separated out under the action of high temperature heat. Subsequently, as the temperature of the fuel continues to rise, about 250 degrees Celsius, thermal synthesis begins, volatiles are released and coke is formed. Gaseous volatiles mixed with surrounding high-temperature air are first ignited and extinguished. Under normal conditions, the coke is surrounded by volatile matter, and the oxygen in the quenching chamber is not easy to soak into the coke surface. As long as the volatile matter is about to be extinguished, the temperature of the coke and its surroundings is very high, and the oxygen in the air may also contact the coke surface, the coke begins to extinguish, and ashes are generated from time to time.
Maintenance method
In order to make biomass boilers operate safely and economically for a long time, it is necessary to strengthen the maintenance of biomass boilers in daily use.
Timely eliminate running, emitting, dripping and leakage.
Regularly add oil to the exposed valves, locking bolts and other movable parts to prevent biting.
The fallen insulation layer shall be repaired in time.
Conduct internal and external inspection on biomass boilers once a year.
Safety common sense
Boiler is a heat energy equipment with high temperature and high pressure. It is one of the special equipment. It is widely used in organs, public institutions and all walks of life. It is a dangerous and special equipment. Once an accident occurs, involving public safety, it will cause huge losses to the country and people's lives and property. For the sake of public safety, people's lives and property safety, according to the regulations on safety supervision of special equipment issued by the State Council, the following items shall be paid attention to when using boilers:
matters needing attention
1. When the boiler leaves the factory, it shall be attached with "design documents required by safety technical specifications, product quality certificate, safety and use and maintenance instructions, supervision and inspection certificate (safety performance supervision and inspection certificate)".
2. Installation, maintenance and transformation of boiler. Units engaged in boiler installation, maintenance and transformation shall obtain the qualification certificate for installation and maintenance of special equipment issued by the Provincial Bureau of quality and technical supervision before engaging in boiler installation, maintenance and transformation. Before construction, the construction unit shall inform the special equipment safety supervision and Management Department of the municipality directly under the central government or the jurisdiction in writing of the proposed installation, maintenance and transformation, and submit the commencement notice to the local county-level Bureau of quality and technical supervision for filing. Construction can be started after notification.
3. Acceptance of boiler installation, maintenance and transformation. After the completion of construction, the construction unit shall apply to the special equipment inspection office of the Bureau of quality and technical supervision for the hydraulic test and installation supervision and inspection of the boiler. After passing the inspection, the quality and Technical Supervision Bureau, the special equipment inspection institute and the county quality and Technical Supervision Bureau shall participate in the overall acceptance.
4. Registration of boilers. After the boiler is accepted, the user must fill in the boiler (census) registration form according to the regulations of the management rules for registration and use of special equipment, register with the Bureau of quality and technical supervision, and apply for the registration certificate for safe use of special equipment.
5. Boiler operation. The boiler must be operated by qualified personnel who have received training and obtained the special equipment operator certificate. The operating procedures, eight systems and six records must be strictly observed during use.
6. Boiler inspection. The boiler shall be subject to regular inspection once a year, and the boiler without regular safety inspection shall not be used. The safety accessories and safety valves of the boiler shall be regularly inspected once a year, and the pressure gauge shall be verified once a half year. The safety accessories without regular inspection shall not be used.
7. It is forbidden to install atmospheric pressure boiler as pressure boiler. It is strictly prohibited to use boilers with incomplete water level gauge, safety valve and pressure gauge.
                                                                     Shijiazhuang Jingjin mechanical equipment installation Co., Ltd