CN212157144U - Biomass low nitrogen gasification device - Google Patents

Abstract

The utility model discloses a biomass low-nitrogen gasification device, which comprises a gasifier, a burner and a boiler. The gas outlet of the gasifier is connected with the fuel inlet of the burner through a pipeline, and the burner is installed in the On the boiler, the boiler is provided with two smoke exhaust ports which are connected to the flue gas side and the chimney of the two regenerative heat exchangers in turn through pipes; the preheating air pipes are respectively connected to the air sides of the two regenerative heat exchangers. Afterwards, they are respectively connected with auxiliary mixing chambers. The auxiliary mixing chamber is provided with a first outlet and is connected with the first inlet of the mixer. The inlet is connected, and the outlet of the mixer is connected with the first inlet of combustion-supporting air of the burner; the chimney is connected with the flue gas inlet of the gasifier and the second inlet of the mixer through pipes and fans. The beneficial effects of the utility model are as follows: the energy is effectively saved, the biomass gas conversion rate is improved, up to 70-78%; the combustion is sufficient, the NOx emission can be effectively reduced, and the NOx emission can be controlled at 80-150mg.

Description

Biomass low nitrogen gasification device

technical field

The utility model relates to the field of biomass gasifiers and boiler systems, in particular to a biomass low-nitrogen gasification device.

Background technique

Fossil fuels are becoming increasingly scarce, and the environmental problems caused by them are becoming more and more serious. As one of the alternative energy sources, bioenergy has received more and more attention. Biomass energy has unique advantages: renewable, low pollution, widely distributed and abundant in total. The development and utilization of biomass energy and other environmentally friendly, renewable and resource-rich clean energy resources are the main strategic measures to solve China's oil and coal shortages, ensure national energy security, protect the ecological environment, and improve my country's sustainable development capabilities.

Bioenergy has high oxygen content, low sulfur content, low ash content, and low emission concentrations of sulfur oxides and nitrogen oxides after combustion. Although the N content of biomass is lower than that of coal, due to the low calorific value of biomass, the N content of biomass is on the same order of magnitude as that of coal, and the nitrogen oxide emissions of biomass combustion products should not be underestimated.

At present, biomass fuels have two combustion methods in heating systems: one is direct combustion in biomass boilers; the other is combustion after gasification. Due to the problem of the structure of the boiler body, the direct combustion cannot meet the environmental protection emission requirements due to the fact that the dust and NOx far exceed the standard; while the post-gasification combustion method also has problems such as low gasification rate (generally lower than 60%) and serious NOx exceeding the standard. Awaiting improvement. At present, the method of gasification and then transportation is often used for combustion, but the process is more complicated, the investment is also large, and there are still problems such as low gasification rate and serious NOx exceeding the standard.

Utility model content

The purpose of the present invention is to provide a biomass low-nitrogen gasification device that can improve the conversion rate of biomass gas and effectively reduce the emission of NOx, aiming at the shortcomings of the existing gasification technologies mentioned above.

In order to achieve the above purpose, the present utility model provides the following technical solutions: a biomass low-nitrogen gasification device, which includes a gasifier, a burner and a boiler, and the gas outlet of the gasifier is connected to the fuel of the burner through a pipeline. Inlet connection, the burner is installed on the boiler, and the boiler is provided with two smoke exhaust ports respectively connected to the inlet of the flue gas side of the regenerative heat exchanger, and the flue gas side of the regenerative heat exchanger is The outlet is connected to the chimney through a pipe, and the flue gas is discharged through the chimney; the preheating air duct is respectively connected to the air side interface of the two regenerative heat exchangers and then connected to the auxiliary mixing chamber, and the auxiliary mixing chamber is provided with a first outlet It is connected with the first inlet of the mixer, the auxiliary mixing chamber is provided with a second outlet and is connected with the high temperature air inlet of the gasifier and the second inlet of the combustion-supporting air of the burner, and the outlet of the mixer is connected with the first inlet of the combustion-supporting air of the burner. The inlet is connected; the chimney is connected with the flue gas inlet of the gasifier and the second inlet of the mixer through pipes and fans.

Control valves are provided on both the flue gas side inlet pipe and the flue gas side outlet pipe of the regenerative heat exchanger.

Control valves are provided on both the air-side inlet pipe and the air-side outlet pipe of the regenerative heat exchanger.

The regenerative heat exchanger includes a shell and a heat storage medium arranged in the shell, and the heat storage medium absorbs the heat of the high-temperature flue gas and is used to heat the incoming low-temperature combustion-supporting air.

The heat storage medium is arranged in three layers in the casing, and three layers are arranged in sequence from the inlet of the flue gas side to the outlet of the flue gas side. And fill the third layer of regenerative cast iron balls.

The porous phase-change ceramic ball is composed of a porous ceramic shell and sodium sulfate encapsulated in the inner cavity of the shell. The average outer diameter of the porous phase-change ceramic ball is 30-50 mm, and the inner diameter of the inner cavity is 20 mm.

The height ratio of the first layer, the second layer and the third layer in the inner space of the casing is 1:2:2.

The burner includes an intake pipe, an outer combustion chamber and an inner combustion chamber, the intake pipe is provided with a first opening to communicate with the combustion outer chamber, and the intake pipe is provided with a second opening in tangential communication with the combustion inner chamber; the combustion The outer cavity is arranged in the jacket space outside the combustion inner cavity, and the end of the combustion outer cavity communicates with the end of the combustion inner cavity.

A premixing cavity is arranged between the combustion outer cavity and the first opening, an air equalizing plate is arranged between the premixing cavity and the combustion outer cavity, and the premixing cavity is communicated with the first opening. The provision of an air uniform plate distributes the biomass gas evenly in the combustion outer cavity, so that the combustion is more uniform and the combustion efficiency is improved.

The air equalizing plate may be a perforated plate.

Compared with the prior art, the beneficial effects of the utility model are: the energy can be effectively saved, the conversion rate of biomass gas can be improved, and the conversion rate can reach 70-78%; Below the national standard, NOx emissions can be controlled at 80-150mg.

Description of drawings

1 is a schematic diagram of the system architecture of the biomass low-nitrogen gasification device of the present invention;

Fig. 2 is the axial sectional schematic diagram of the burner in the biomass low nitrogen gasification device of the present invention;

Fig. 3 is the left side schematic diagram of the burner in the biomass low nitrogen gasification device of the present invention;

4 is a cross-sectional view of a regenerative heat exchanger in the biomass low nitrogen gasification device of the present invention.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

A biomass low nitrogen gasification device, as shown in Figure 1, includes a gasifier 1, a burner 2 and a boiler 3, and the gas outlet of the gasifier 1 is connected to the fuel inlet of the burner 2 through a pipeline , the burner 2 is installed on the boiler 3, and the boiler 3 is provided with two smoke exhaust ports respectively connected to the flue gas side inlets of the regenerative heat exchangers (41, 42). The flue gas side outlets of the heaters (41, 42) are connected to the chimney 5 through pipes, and the heat-exchanged flue gas is discharged through the chimney 5. The preheating air duct is provided with branch pipes respectively connected to the air side interfaces of the two regenerative heat exchangers (41, 42) and then connected to the auxiliary mixing chamber 7 respectively. The heated air is collected in the auxiliary mixing chamber 7, the purpose is to balance the preheated air temperature of the two regenerative heat exchangers (41, 42), and to ensure that the mixer 8 always has the amount of hot air, which can continuously supply and mix device 8. The auxiliary mixing chamber 7 may be a cavity for storing and buffering preheated air. The auxiliary mixing chamber 7 is provided with a first outlet to be connected to the first inlet of the mixer 8, and the chimney 5 is provided with a pipeline to be connected to the second inlet of the mixer 8 through the fan 6 for introducing part of the flue gas and high-temperature combustion air. Mixing takes place in mixer 8 . The mixer 8 is preferably a gas mixer. The outlet of the mixer 8 is connected to the first inlet 28 of the combustion air of the burner 2 . The auxiliary mixing chamber 7 is provided with a second outlet connected to the high-temperature air inlet of the gasifier 1 and the second inlet 29 of the combustion-supporting air of the burner 2. Using high-temperature air for gasification can increase the gasification temperature, thereby increasing the biomass gas. the combustion temperature, thereby effectively improving the gasification efficiency. The chimney 5 is connected to the flue gas inlet of the gasifier 1 through a pipeline and a fan 6, and uses the waste heat of the flue gas to preheat the biomass in the gasifier 1, thereby effectively reducing the emission of nitrogen oxides.

Wherein, a control valve 9 is provided on both the flue gas side inlet pipe and the flue gas side outlet pipe of the regenerative heat exchanger (41, 42). The air side inlet pipe and the air side outlet pipe of the regenerative heat exchanger (41, 42) are both provided with control valves 9, through which the flow direction of flue gas or combustion-supporting air can be regulated. The control valve 9 is preferably a solenoid valve.

The regenerative heat exchanger (41, 42) is shown in FIG. 4, which includes a shell and a heat storage medium arranged in the shell, and the shell is provided with a flue gas side inlet 48 and a flue gas side outlet 49 , an air side inlet 47 and an air side outlet 46 . The heat storage medium absorbs the heat of the high temperature flue gas, and is then used to heat the incoming low temperature combustion air. Wherein, the heat storage medium is arranged in layers in the shell, so as to improve the heat exchange efficiency. The heat storage medium is arranged in three layers in the shell, from the flue gas side inlet 48 to the flue gas side outlet 49 are sequentially provided with three layers, which are respectively the first layer filled with porous phase change ceramic balls, and the first layer filled with heat storage ceramic balls. The second layer and the third layer filled with regenerative cast iron balls. The first layer of porous phase-change ceramic balls has refractory function, high heat capacity and fast heat transfer. The waste heat of flue gas can be stored in the phase-change medium in the ceramic ball as a heat storage body, and the melting of the phase-change medium Absorb the waste heat of the high-temperature flue gas, and release heat through the solidification of the phase change medium to heat the low-temperature combustion-supporting air; the flue gas after the first heat exchange passes through the heat-storage ceramic balls with relatively small heat storage in turn, and then passes through the heat-storage ceramic ball with a smaller heat storage capacity. The cast iron balls are used for heat exchange, which can effectively absorb the waste heat of the flue gas and improve the heat exchange efficiency. The porous phase-change ceramic ball is composed of a porous ceramic shell and sodium sulfate encapsulated in the inner cavity of the shell. After the sodium sulfate absorbs heat, phase-change heat storage is generated in the inner cavity of the shell, and the heat storage is very high. The average outer diameter of the porous phase change ceramic ball is 30-50mm, and the inner diameter of the inner cavity is about 20mm. Among them, the height ratio of the first layer, the second layer and the third layer in the inner space of the shell is 1:2:2, which can maximize the heat exchange with the flue gas, absorb the waste heat of the flue gas, and also maximize the heat exchange with the flue gas. The air exchanges heat and heats the air.

As shown in Figures 2-3, the burner includes an intake pipe 21, a combustion outer cavity 25 and a combustion inner cavity 26. The intake pipe 21 is provided with a first opening 22 to connect with the combustion outer cavity 25 to connect part of the biomass gas Input the combustion outer cavity 25 for combustion; the intake pipe 21 is provided with a second opening 27 that is tangentially connected to the combustion inner cavity 26, and the remaining biomass gas is input into the combustion inner cavity 26 for rotary combustion; The double flame is superimposed, and the combustion is more complete, which can effectively improve the combustion efficiency and reduce the emission of NOx. The outer combustion chamber 25 is arranged in the jacket space formed by the outer combustion chamber 26 and the casing, and the end of the outer combustion chamber 25 communicates with the end of the inner combustion chamber 26, so that the flames of the inner and outer layers burn at the exit. Superimposed to further improve combustion efficiency. A premixing chamber 23 is arranged between the outer combustion chamber 25 and the first opening 22 , an air equalizing plate 24 is arranged between the premixing chamber 23 and the outer combustion chamber 25 , and the premixing chamber 23 is connected to the first opening 22 In the same way, the biomass gas is evenly distributed in the combustion outer cavity 25 by the air equalizing plate 24, so that the combustion is more uniform and the combustion efficiency is improved. A guide block 30 is provided at the first opening 22 for evenly overflowing the fuel in the air uniform plate 24 under the guidance of the guide block, so as to achieve the purpose of evenly distributing the fuel. Wherein, the air equalizing plate 24 may be a perforated plate. The combustion outer cavity 25 is provided with a first combustion air inlet 28 , and the combustion air first inlet 28 and the combustion outer cavity 25 may be tangentially connected. The first inlet 28 of combustion-supporting air refers to a mixture of high-temperature air and flue gas, which can effectively improve the combustion efficiency. The combustion inner cavity 26 is provided with a second combustion air inlet 29 , and the combustion air second inlet 29 is connected to the combustion inner cavity 26 . The combustion-supporting air second inlet 29 refers to high-temperature air, which can effectively increase the combustion temperature to ensure stable ignition of the fuel, and overlap with the flame of the combustion outer cavity 25 to effectively reduce nitrogen oxide emissions.

The two discharge ports of the boiler of the utility model are respectively connected with the air inlets of the regenerative heat exchangers (41, 42), and the air exhaust ports of the two regenerative heat exchangers (41, 42) are connected to the chimney 5, Discharge the treated exhaust gas. During operation, when the boiler exhaust gas enters the chimney 5 from the first regenerative heat exchanger 41, the combustion-supporting air enters the auxiliary mixing chamber 7 after passing through the second regenerative heat exchanger 42; The regenerative heat exchanger 42 enters the chimney 5, and the combustion-supporting air enters the auxiliary mixing chamber 7 after passing through the first regenerative heat exchanger 41. The two regenerative heat exchangers (41, 42) perform switching heat exchange, to improve heat exchange efficiency. The flue gas discharged from the boiler passes through the heat storage medium and is output to the chimney 5 from the exhaust port, and the high temperature flue gas heats the heat storage medium to 700°C-800°C when passing through the heat storage medium in the heat storage heat exchanger (41, 42). . After the set time, the switch is controlled by the control valve 9, the intake control valve 9 of the current regenerative heat exchanger (41, 42) is closed, the combustion air pipe control valve 9 is opened, and another regenerative heat exchanger (41, 42) is opened. 41, 42) Intake control valve 9, and close its control valve 9; the temperature of exhaust gas is reduced to 100°C-150°C after heat absorption by the heat storage medium in the regenerative heat exchanger (41, 42), It is then discharged into the chimney 5 while heating the heat storage medium in the regenerative heat exchangers (41, 42). The combustion-supporting air is heated by the heat storage medium in the regenerative heat exchangers (41, 42), and then the temperature rises to 650°C-750°C and then enters the auxiliary mixing chamber 7 . In the switching of flue gas emission, the residual heat of the flue gas after combustion is fully utilized to preheat the combustion-supporting air, which can effectively save energy and improve the treatment effect.

The gasifier of the utility model is in accordance with NY/T2907-2016 "Technical Conditions for Biomass Atmospheric Pressure Fixed Bed Gasifier", NY/T1417-2007 "Technical Specification for Quality Evaluation of Straw Gasifier" and GB/T10180-2017 The standard test method of "Experimental Regulations on Thermal Performance of Industrial Boilers" shows that the gasification efficiency is over 70%, the gas calorific value is 4.48MJ/Nm3, and the gas yield is 2.5m3/kg.

The flue gas emission of the biomass low nitrogen gasification device of the utility model refers to HJ57-2017 "Fixed Pollution Source Waste Gas-Determination of Sulfur Dioxide-Constant Potential Electrolysis", GB/13271-2047 "Boiler Air Pollutant Emission Standard", GB/T16157- 1996 "Sampling Methods for Particulate Matter and Gaseous Pollutants in Exhaust from Stationary Pollution Sources", GB/T10180-2017 "Experimental Regulations on Thermal Performance of Industrial Boilers", GB/5468-1991 "Test Methods for Boiler Smoke and Dust" The data obtained by the standard test are, nitrogen The oxide is controlled between 80-150mg/m3, the average detection value is generally 130mg/m3, and the oxygen content is 5.1-5.4%.

The above are only preferred embodiments of the present invention, and should not limit the scope of implementation of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the description of the new model are all It still falls within the scope of the new patent.

Claims (10)

1. a biomass low nitrogen gasification device, it is characterized in that, it comprises gasifier, burner and boiler, the gas outlet of described gasifier is connected with the fuel inlet of described burner by pipeline, described burner Installed on the boiler, the boiler is provided with two smoke exhaust ports connected to the chimney through pipes; a regenerative heat exchanger is respectively installed between the smoke exhaust port and the chimney, and the preheating air duct is respectively connected with the two storage tanks. After the thermal heat exchanger is connected, it is respectively connected with the auxiliary mixing chamber. The auxiliary mixing chamber is provided with a first outlet and is connected with the inlet of the mixer. The second inlet of combustion-supporting air is connected, the outlet of the mixer is connected to the first inlet of combustion-supporting air of the burner; the chimney is connected to the flue gas inlet of the gasifier through pipes and fans. 2 . The biomass low nitrogen gasification device according to claim 1 , wherein a control valve is provided in the flue gas inlet pipe and the flue gas outlet pipe of the regenerative heat exchanger. 3 . 3 . The biomass low nitrogen gasification device according to claim 2 , wherein the preheated air outlet pipe and the preheated air outlet pipe of the regenerative heat exchanger are both provided with control valves. 4 . 4 . The biomass low nitrogen gasification device according to claim 3 , wherein the regenerative heat exchanger comprises a shell and a heat storage medium arranged in the shell. 5 . 5 . The biomass low nitrogen gasification device according to claim 4 , wherein the heat storage medium is arranged in three layers in the casing, and three layers are arranged in sequence from the inlet of the flue gas side to the outlet of the flue gas side, 6 . They are the first layer filled with porous phase change ceramic balls, the second layer filled with heat storage ceramic balls and the third layer filled with heat storage cast iron balls. 6. A biomass low-nitrogen gasification device according to claim 5, wherein the porous phase-change ceramic ball is composed of a porous ceramic shell and sodium sulfate encapsulated in the inner cavity of the shell, and the porous phase-change ceramic ball averages The outer diameter is 30-50mm, and the inner diameter of the inner cavity is 20mm. 7 . The biomass low nitrogen gasification device according to claim 6 , wherein the height ratio of the first layer, the second layer and the third layer in the inner space of the shell is 1:2:2. 8 . 8 . The biomass low nitrogen gasification device according to claim 3 , wherein the burner comprises an intake pipe, an outer combustion chamber and an inner combustion chamber, and the intake pipe is provided with a first opening and an outer combustion chamber. 9 . Connected and communicated, the intake pipe is provided with a second opening in tangential communication with the combustion inner cavity; the combustion outer cavity is arranged in the jacket space outside the combustion inner cavity, and the end of the combustion outer cavity is communicated with the combustion inner cavity. . 9 . The biomass low-nitrogen gasification device according to claim 8 , wherein a premixing cavity is provided between the combustion outer cavity and the first opening, and a premixing cavity is provided between the premixing cavity and the combustion outer cavity. 10 . an air equalizing plate, the premixing cavity is communicated with the first opening, and the air equalizing plate is arranged to evenly distribute the biomass gas in the combustion outer chamber. 10 . The biomass low-nitrogen gasification device according to claim 9 , wherein the air equalizing plate is a porous plate. 11 .

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