CN103912884A - Biomass carbonization furnace tail gas treatment device - Google Patents

Abstract

The invention discloses a biomass carbonization furnace tail gas treatment device, which comprises a shunt pipe, an air distribution port, a steady flow cover, a heat-resistant insulating seat, a high-temperature resistant wire, a resistance wire, an energy-saving net, a burner wall, a flame detector, etc. The preheating ignition zone composed of resistance wire and energy-saving net can fully burn the tail gas generated by the biomass carbonization furnace, achieving energy saving, high efficiency, clean and environmental protection. It can further cooperate with steam generators and batteries to realize energy recovery and reduce fossil energy input. The invention also provides an operation method for using the equipment to treat tail gas, including the steps of voltage regulation, power supply, and power cutoff.

Description

A biomass carbonization furnace tail gas treatment device

technical field

The invention relates to the field of agricultural machinery, in particular to a biomass carbonization furnace tail gas treatment device.

Background technique

my country is a large agricultural country, and the total resources of crop straw alone have exceeded 700 million tons, nearly half of which were discarded or burned on the spot, which not only caused a serious waste of biomass resources, but also destroyed the soil structure and made the cultivated land productive The decline in capacity has also led to serious environmental pollution, threatening transportation and people's production and living safety. If these discarded biomass resources can be prepared into biochar through carbonization technology and returned to the soil, it will be an effective way to increase soil input and improve soil quality, and it will be of great significance to promote the sustainable development of agricultural cycles.

Biomass carbonization, specifically referring to the process of converting biomass into biochar, is one of the comprehensive utilization methods of low-value agricultural and forestry waste resources such as straw (Chen Wenfu, et al. Research on Biochar Application Technology. China Engineering Science. 2011, 13(2 ): 83-89; Meng Jun, et al. The Development and Prospect of Carbonization and Returning Agricultural and Forestry Wastes. Journal of Shenyang Agricultural University. 2011, 42(4): 387-392). But in the carbonization process, only about 30% of the material is finally converted into biochar, and about 30% of the material is discharged in the form of gas. These gases not only contain H ₂ O and CO ₂ , but also combustible gases such as CO, CH ₄ and H ₂ , which may cause air pollution if not handled properly.

In the traditional gasification process, combustible gas is the main target product, and the gas is of good quality and easy to use. But this is at the cost of reducing the carbon content of the solid product, that is, the reaction of H ₂ O and CO ₂ with C to generate H ₂ and CO. In the carbonization process whose main goal is to obtain biochar, in order to ensure that the biochar has a high carbon content, the H ₂ O and CO ₂ of the combustible gas are relatively high, which is not easy to ignite.

In order to solve the pollution problem of biomass carbonization furnace tail gas, there are two common methods at present. One is to add gas purification equipment to remove water vapor, and then ignite it with an open flame. The disadvantage of this method is that the equipment cost is high, and it is unstable due to the type of biomass raw material. The second is to add a burner with liquefied petroleum gas or other high-purity combustible gas as the ignition device at the end of the carbonization equipment, and keep it lit during the production process to ensure the combustion of the carbonization furnace tail gas. The disadvantage of this method is that non-renewable fossil energy is used, which increases production input and production cost of biochar, and there are certain safety hazards.

Contents of the invention

The invention provides a biomass carbonization furnace tail gas treatment device with resistance wire preheating as the key technology, and its purpose is to solve the problems existing in the prior art such as high input of fossil energy, potential safety hazards, and difficulty in handling tail gas with low combustible gas content.

The invention provides a biomass carbonization furnace tail gas treatment device, the tail gas treatment device includes a shunt pipe 3, an air distribution port 4, a steady flow cover 5, a heat-resistant insulating seat 6, a resistance wire 8, an energy-saving net 9 and a burner wall 10;

The shunt pipe 3 is connected with the exhaust gas of the carbonization furnace. The flow stabilization hood 5 is covered on the shunt pipe, and the upper end is narrowed to form a neck. The neck of the flow stabilization hood is divided into three layers, and two layers of resistance wires 8 and 1 are distributed from bottom to top. Layer energy-saving net 9, resistance wire 8 is placed on the heat-resistant insulating seat 6; the bottom of the steady flow cover 5 is sealed and connected with the bottom of the burner wall 10, the diameter of the bottom of the burner wall is greater than the diameter of the bottom of the steady flow cover, and the bottom of the burner wall 10 is set There is a distribution outlet 4.

Preferably, the upper end surface of the distribution pipe 3 is closed, and air holes are opened on the peripheral wall of the pipe, and the total area of the air holes is larger than the cross-sectional area of the exhaust gas outlet pipe 1 . The upper portion of the burner wall 10 is provided with an air distribution port 11 . The neck of the burner wall 10 is provided with a flame detector 12 .

The method of using the above-mentioned device is to connect the resistance wire before starting the carbonization furnace, and start the carbonization furnace after the resistance wire turns red, so that the tail gas of the carbonization furnace enters the tail gas treatment device, and the combustible gas with extremely low content is heated in the high temperature of the resistance wire. The surface and the high-temperature surface of the energy-saving net are ignited, and no flame can be formed at this time. When the content of combustible gas in the exhaust gas of the carbonization furnace increases, after passing through the heating zone formed by two layers of resistance wire and the energy-saving net, the combustible gas is ignited by the high-temperature surface A flame is formed. At this time, turn off the power supply of the resistance wire. When the flame is extinguished, turn off the power supply of the resistance wire, preheat and ignite again. This reciprocating cycle ensures that the exhaust gas of the biomass carbonization furnace is fully burned.

The tail gas treatment device provided by the present invention has a cylindrical shape as a whole, including a shunt pipe 3, an air distribution port 4, a steady flow cover 5, a heat-resistant insulating seat 6, a high-temperature resistant wire 7, a resistance wire 8, an energy-saving net 9, a burner wall 10, Composed of a flame detector 12, it is connected with the exhaust gas outlet 1 of the biomass carbonization furnace through an elbow 2 with a flange.

In order to reduce the gas velocity and stabilize the gas flow, the upper end surface of the splitter pipe 3 is closed, and a number of air holes are opened on the wall around the pipe. The total area of the air holes is larger than the cross-sectional area of the tail gas outlet pipe 1 .

In order to stabilize the air flow, a steady flow cover 5 is set, which is cylindrical, and the upper end is narrowed to form a neck.

In order to preheat and ignite the exhaust gas, the neck of the swirl cover 5 is divided into three layers. From bottom to top, there are two layers of resistance wires 8 and one layer of energy-saving net 9, forming a preheating and ignition zone.

In order to prevent leakage, the resistance wire 8 is placed on the heat-resistant insulating seat 6, and connected to the voltage regulator through the high-temperature resistant wire 7.

In order to increase the contact area between the heat source and the combustible gas to achieve sufficient surface combustion or ignition, the energy-saving net 9 is placed on the top of the neck of the stabilizing hood.

In order to keep warm and insulate, set the burner wall 10, which is cylindrical, connected to the bottom of the swirl cover 5 and sealed.

In order to fully burn the combustible gas with oxygen, the lower part of the burner wall 10 is provided with an air distribution port 4, and the upper part is provided with an air distribution port 11. The height of the upper part of the air distribution port is not lower than the energy-saving net 9 to prevent cooling.

In order to mix air and combustible gas evenly, the upper end of the burner wall 10 is narrowed to form a neck, forming a turbulent flow zone.

In order to detect combustible gas combustion conditions, the neck of the burner wall 10 is provided with a flame detector 12, and its probe is installed on the wall of the burner neck, and is aligned with the vertical line of the center of the energy-saving net 9.

After the tail gas of the biomass carbonization furnace enters the shunt pipe 3, it enters the inside of the steady flow cover 5 through the vent hole, and the flow velocity decreases and stabilizes, and then passes through two layers of resistance wires 8 and energy-saving nets 9 in sequence. When the concentration of combustible gas is low, the gas burns in a small area on the high-temperature surface of the resistance wire and the energy-saving net; when the concentration of combustible gas is high, the gas can be directly ignited by the resistance wire and the high-temperature surface of the energy-saving net after preheating to form an open flame, thereby Achieve exhaust gas treatment goals.

The present invention further provides a method for using the above tail gas treatment device.

Before starting the carbonization furnace, adjust the output voltage of the voltage regulator to a safe voltage of 36V and connect the resistance wire. Start the carbonization furnace after the resistance wire turns red, and allow the exhaust gas of the carbonization furnace to enter the exhaust gas treatment device. At this time, the exhaust gas is mainly water vapor, and the combustible gas with extremely low content is ignited on the high-temperature surface of the resistance wire and the high-temperature surface of the energy-saving net. No flames can form at this time. When the content of combustible gas in the exhaust gas of the carbonization furnace is high, it can be ignited by the high-temperature surface to form a flame after passing through the heating zone formed by two layers of resistance wire and energy-saving net. At this time, the power supply of the resistance wire can be turned off, and the flame detector can be used to detect the combustion condition. When the gas is unstable and the flame is extinguished, the flame detector sends out a signal to close the power supply of the resistance wire, and then preheat and ignite again. Such a reciprocating cycle can ensure that the tail gas of the biomass carbonization furnace is fully burned.

Compared with tail gas treatment devices that require complex purification equipment and tail gas combustion devices driven by fossil energy, the biomass carbonization furnace tail gas treatment device provided by the present invention has the following advantages:

1. Replace traditional fossil energy such as natural gas or liquefied petroleum gas with renewable electric energy. The electric energy used in the present invention is provided by accumulators during the start-up stage of the equipment; when the tail gas is combustible, the steam generator driven by it energizes the resistance wires and charges the accumulators at the same time. The excess electric energy can be used to drive other devices of the carbonization equipment.

2. High security. The resistance wire works at a safe voltage of 36V, which will not cause harm to the human body. However, when using natural gas or liquefied petroleum gas, it is necessary to pay attention to anti-leakage and explosion-proof, and there are potential safety hazards.

3. High efficiency. In the initial stage of biomass carbonization, the content of combustible gas in the tail gas is low, and it is difficult for ordinary purification equipment to purify it to the extent that it can be ignited, and it is difficult to treat it by combustion. The present invention oxidizes the surface of the resistance wire and the energy-saving net at high temperature, that is, burns in a small area on the high-temperature surface, thereby improving the exhaust gas purification efficiency. Because of this, the equipment is less affected by the type of raw materials, and the tail gas treatment effect is stable.

Description of drawings

Fig. 1 is a schematic structural diagram of a biomass carbonization furnace tail gas treatment device according to the present invention.

Among them: 1) exhaust gas outlet pipe, 2) elbow, 3) shunt pipe, 4) air distribution port, 5) steady flow cover, 6) heat-resistant insulating seat, 7) high-temperature resistant wire, 8) resistance wire, 9) energy saving Net, 10) burner wall, 11) distribution outlet, 12) flame detector.

Fig. 2 is the real picture of the biomass carbonization furnace tail gas treatment device of the present invention

Detailed ways

The biomass carbonization furnace tail gas treatment device provided by the present invention can be connected to the tail gas outlet of the biomass particle carbonization furnace for use, such as the semi-closed particle carbonization furnace described in the Chinese invention patent whose patent number is ZL200710086505.4, or the patent number is A combined biomass particle carbonization furnace described in the Chinese invention patent of ZL201110073104.1.

The biomass may be one or a mixture of corn cobs, straw, peanut husks, rice husks, discarded mushroom trays for production, etc., but is not limited thereto.

The tail gas treatment device of the present invention, as shown in Figure 1, includes a tail gas outlet pipe 1, an elbow 2, a shunt pipe 3, an air distribution port 4, a steady flow cover 5, a heat-resistant insulating seat 6, a high-temperature resistant wire 7, a resistance Wire 8, energy-saving net 9, burner wall 10, air distribution port 11, flame detector 12, etc.

The exhaust gas outlet pipe 1, elbow 2, shunt pipe 3, air distribution port 4, steady flow cover 5, burner wall 10, etc. can be made of various types of ordinary carbon steel or stainless steel plates or pipes, preferably 304 stainless steel Manufactured, the thickness is not less than 1mm.

The diameter of the shunt pipe 3 is 8-13.3cm, the upper end surface is closed, and the height is 20-40cm, preferably 30cm; the pipe circumference wall has a number of air holes with a diameter of 1-2cm, preferably 1cm; the total area of the air holes should be greater than the exhaust gas outlet pipe 1 of cross-sectional area.

The diameter of the air distribution port 4 is 3-5 cm, and the end is equipped with a ball valve or a butterfly valve to control the air distribution volume, preferably a butterfly valve.

The diameter of the bottom of the described steady flow hood 5 is 20-30cm, preferably 25cm; the diameter at the top end is 10-20cm, preferably 15cm; the height of the steady flow hood is 30-50cm, preferably 40cm; the height of the neck of the steady flow hood is 10-20cm , preferably 15cm. Two layers of heat-resistant insulating seats 6 are established at the lower end and the middle of the neck, 4-6 of each layer; energy-saving net 9 is installed at the top of the neck.

The heat-resistant insulating seat 6 is a cuboid with a length of 3 cm, a width of 2 cm, and a height of 2 cm. The upper surface has a semicircular depression with a depth of 1 cm to embed the resistance wire. It can be made of any refractory insulating material, such as high-temperature-resistant ceramics or refractory cement. In order to facilitate processing into a central depression for fixing the resistance wire, it is preferably made of refractory cement.

The high-temperature-resistant wire 7 is a copper core, an insulating layer composed of mica tape and glass fiber braiding, and the rated temperature is above 500°C. It is preferably a high-temperature-resistant wire with a pure nickel core and is covered with a ceramic tube to prevent leakage.

The resistance wire 8 is made of iron-chromium-aluminum or nickel-chromium electric heating alloy, preferably nickel-chromium electric heating alloy resistance wire.

The energy-saving net 9 is a mesh structure wound with stainless steel wires or resistance wires, preferably a 20-mesh mesh structure, and is not energized.

The flame detector is an infrared flame detector, an ultraviolet flame detector or a visible light flame detector.

Pressure regulators are commonly used equipment in this field and are not listed in Figure 1.

Resistance wires, voltage regulators, high temperature resistant wires, and flame detectors are all commonly used equipment, which are available in electronic markets, and those skilled in the art can freely choose according to known knowledge.

The size of the tail gas treatment device can be adjusted according to the exhaust gas emission of the carbonization furnace.

Example 1 Biomass carbonization furnace tail gas treatment device

The device is composed of a shunt pipe 3, an air distribution port 4, a steady flow cover 5, a heat-resistant insulating seat 6, a high-temperature resistant wire 7, a resistance wire 8, an energy-saving net 9 and a burner wall 10. The tail gas outlet of the biomass carbonization furnace is connected to 1; the diversion pipe 3 has a diameter of 8cm, the upper end surface is closed, and the height is 30cm. The surrounding wall of the pipe has vent holes with a diameter of 1cm. The vent holes are 10 layers, 8 in each layer, and are evenly distributed; The end is equipped with a ball valve to control the air volume; the lower part of the flow stabilization cover 5 has a diameter of 25cm and a height of 30cm, and the neck has a diameter of 15cm and a height of 15cm; the neck of the flow stabilization cover 5 is equipped with two layers of heat-resistant insulating seats 6, 4 for each layer; heat-resistant insulation The seat 6 is made of refractory cement, 3cm long, 2cm wide, and 2cm high, with a central depression on the upper surface and a depth of 1cm; the high-temperature-resistant wire 7 is a copper core, mica tape, and glass fiber wire braid to form an insulating layer, and the rated temperature is above 500 ° C. Outer jacket ceramic tube; resistance wire 8 is a nickel-chromium electric heating alloy resistance wire, single power 2KW; energy-saving net 9 is a 20-mesh mesh structure wound by stainless steel wire; the lower part of the burner wall 10 has a diameter of 40cm, a height of 50cm, and a neck The diameter is 25cm, the height is 10cm, and 30 air distribution holes with a diameter of 1cm are opened at a distance of 45cm from the bottom surface; the pressure regulator is a single-phase TDGC2 pressure regulator 5KVA; the upper half of the burner wall has an observation window with a width of 20cm and a height of 12cm; The distribution pipe 3, the air distribution port 4, the swirl cover 5 and the burner wall 10 can be made of 3mm thick carbon steel plates and pipes, but are not limited thereto.

Example 2 Biomass carbonization furnace tail gas treatment device

This embodiment is substantially the same as Embodiment 1, except that a Honeywell C7927 cured ultraviolet flame detector is installed on the neck of the burner wall 10 for automatic control of the resistance wire power switch. Automatic control parts are well known to those skilled in the art and are not listed in the description.

Example 3 Exemplary Production Method of Biomass Carbonization Furnace Tail Gas Treatment Device

This example is based on Example 1, combined with the use method of a combined biomass particle carbonization furnace described in the Chinese invention patent No. ZL201110073104.1, and exemplarily describes the use of the biomass carbonization furnace provided by the present invention The use of the tail gas treatment device includes steps such as voltage regulation, power supply, and power cutoff, but is not limited thereto.

Voltage regulation: Before starting the carbonization furnace, connect the voltage regulator to an external power supply or a steam generator, and adjust the voltage to below the safe voltage of 36V.

Power supply: turn on the resistance wire power supply, start the carbonization furnace when the resistance wire turns red, and let the carbonization furnace exhaust gas enter the exhaust gas treatment device.

Power cut: cut off the resistance wire power supply when the exhaust gas burns to form a flame.

When the flame is extinguished, the power is supplied again, and the reciprocating operation is performed.

When the carbonization is completed, before the charcoal is discharged, the power is turned off, and the voltage regulator is turned off to cut off the power supply.

Example 4 Exemplary Production Method of Biomass Carbonization Furnace Tail Gas Treatment Device

This example is based on Example 2, combined with the use method of a combined biomass particle carbonization furnace described in the Chinese invention patent No. ZL201110073104.1, and exemplarily describes the use of the biomass carbonization furnace provided by the present invention The use of the tail gas treatment device includes steps such as voltage regulation, power supply, and power cutoff, but is not limited thereto.

Voltage regulation: Before starting the carbonization furnace, connect the voltage regulator to an external power supply or a steam generator, and adjust the voltage to below the safe voltage of 36V.

Power supply: turn on the resistance wire power supply, start the carbonization furnace when the resistance wire turns red, and let the carbonization furnace exhaust gas enter the exhaust gas treatment device.

Power-off: Automatically control the opening and closing of the resistance wire power supply according to the electrical signal provided by the flame detector.

When the carbonization is completed, before the charcoal is discharged, the power is turned off, and the voltage regulator is turned off to cut off the power supply.

Example 5 Technical Effect of Biomass Carbonization Furnace Tail Gas Treatment Device

This example demonstrates the effect of biomass carbonization furnace exhaust gas treatment in Example 3, see accompanying drawing 2 of the description. It can be seen that the exhaust gas is completely combusted at the outlet of the device. In order to facilitate the observation of the exhaust gas treatment effect, the turbulent projection of the hot air is marked with a circle in Figure 2, indicating that the exhaust gas treatment is complete.

The above embodiments are only used to explain the present invention, and should not be construed as specific limitations to the present invention.

Claims (4)

1. A biomass carbonization furnace tail gas treatment device is characterized in that the tail gas treatment device comprises a shunt pipe (3), an air distribution port (4), a steady flow cover (5), a heat-resistant insulating seat (6), a resistance wire ( 8), energy-saving net (9) and burner wall (10); The shunt pipe (3) is connected to the exhaust gas of the carbonization furnace. The flow stabilization cover (5) is covered on the flow distribution pipe, and the upper end is narrowed to form a neck. The neck of the flow stabilization cover is divided into 3 layers, and 2 layers of resistance are distributed from bottom to top. Wire (8) and 1 layer of energy-saving mesh (9), the resistance wire (8) is placed on the heat-resistant insulating seat (6); the bottom of the steady flow cover (5) is sealed with the bottom of the burner wall (10), and The bottom diameter is greater than the bottom diameter of the steady flow cover, and the lower part of the burner wall (10) is provided with an air distribution port (4). 2. The device according to claim 1, characterized in that: the upper end surface of the shunt pipe (3) is closed, and air holes are opened on the wall around the pipe, and the total area of the air holes is larger than the cross-sectional area of the exhaust gas outlet pipe (1). 3. The device according to any one of claims 1-3, characterized in that: the neck of the burner wall (10) is provided with a flame detector (12). 4. The use method of any one of claims 1-4, before the carbonization furnace starts, connect the resistance wire, start the carbonization furnace after the resistance wire turns red, and allow the carbonization furnace tail gas to enter the described tail gas treatment device, the content The extremely low combustible gas is ignited on the high-temperature surface of the resistance wire and the high-temperature surface of the energy-saving net, and no flame can be formed at this time. After the zone, the combustible gas is ignited by the high-temperature surface to form a flame. At this time, turn off the power supply of the resistance wire. When the flame is extinguished, turn off the power supply of the resistance wire, and preheat and ignite again. This reciprocating cycle ensures that the exhaust gas of the biomass carbonization furnace is fully burned.