An oxygen-free medium-temperature downdraft pyrolysis device

Abstract

The present invention discloses an oxygen-free medium-temperature downdraft pyrolysis device, including a pyrolysis furnace, a grate is arranged in the pyrolysis furnace, a feed port is arranged at the pyrolysis furnace above the grate, a closed feeder is arranged at the feed port, a discharge port is arranged at the pyrolysis furnace below the grate, a closed discharger is arranged at the discharge port, and an oxygen-free medium-temperature gas source mechanism is arranged outside the pyrolysis furnace and supplies flue gas to the pyrolysis furnace, the oxygen-free medium-temperature gas source mechanism includes a burner, and the pyrolysis furnace is provided with a combustible gas collector below the grate to form a downdraft structure; the combustible gas collector is guided outward to the outside of the pyrolysis furnace through a gas collection pipeline. The present invention forms a medium-temperature temperature field in the pyrolysis furnace, which can effectively control the precipitation temperature, ensure that the biomass in the pyrolysis furnace is at the optimal precipitation temperature for precipitating combustible gas, and thus ensure the precipitation effect of the combustible gas.

Description

Technical Field

[0001] The invention relates to the technical field of biomass pyrolysis, and in particular to an anaerobic medium-temperature downdraft pyrolysis device. Background Art

[0002] Biomass gasification is a process in which, under certain thermodynamic conditions, with the help of part of the air (or oxygen) and water vapor, the polymers of biomass undergo pyrolysis, oxidation, and reduction reforming reactions, and are ultimately converted into combustible gases such as carbon monoxide, hydrogen, and low molecular weight hydrocarbons.

[0003] The key to biomass gasification lies in the gasifier. Currently used gasifiers include updraft, downdraft, open and fluidized bed. The reaction process of different biomass is also different. Common gasifier reactions can be divided into oxidation layer, reduction layer, cracking layer and drying layer:

[0004] 1) Oxidation layer: The main reaction of biomass in the oxidation layer is oxidation reaction. The gasifier is introduced from the lower part of the grate and enters the oxidation layer after absorbing heat in the ash layer. Here, a combustion reaction occurs through the high-temperature carbon to generate a large amount of carbon dioxide and release heat at the same time. The temperature can reach 1000~1300 degrees Celsius. The combustion in the oxidation layer is an exothermic reaction. This part of the reaction heat is the reduction reaction of the reduction layer, and provides a heat source for the cracking and drying of the material.

[0005] 2) Reduction layer: The carbon dioxide and carbon generated in the oxidation layer undergo reduction reaction with water vapor.

[0006] 3) Cracking layer: The hot gas generated by the oxidation layer and the reduction layer passes through the cracking layer during the upward process, heating the biomass and causing the biomass in the cracking zone to undergo cracking reaction.

[0007] 4) Drying layer. The gas products from the oxidation layer, reduction layer and cracking layer rise to this zone, heating the biomass raw materials, evaporating the water in the raw materials, absorbing heat, and reducing the generated temperature. The outlet temperature of the biomass gasifier is generally 100~300℃

[0008] The above-mentioned oxidation layer and reduction layer are collectively referred to as the gasification zone, where the gasification reaction mainly takes place; the cracking layer and drying layer are collectively referred to as the fuel preparation zone.

[0009] For example, the invention disclosed in announcement number CN110484306A discloses a composite biomass graded gasification furnace, including a furnace body, a grate is fixed on the lower side wall inside the furnace body, the space below the grate is a slag chamber, an ash discharge port is arranged on the side wall of the furnace body corresponding to the slag chamber, a filter is also fixed on the inner wall of the furnace body, the filter is located above the grate, and a pyrolysis chamber is formed between the filter and the grate, a fine filter is fixed on the top wall inside the furnace body, a feeding mechanism is fixed on the outer side of the furnace body, a primary filtering mechanism is fixed on the feeding mechanism, the primary filtering mechanism is connected to the feeding mechanism through a feeding pipe, and the primary filtering mechanism is connected to the upper side wall of the furnace body and the fine filtering mechanism through air pipe one and air pipe two, respectively.

[0010] For example, the invention disclosed in announcement number CN110452736A discloses a downdraft carbon-gas co-production gasifier, whose main structures from top to bottom are respectively a feed hopper, a silo, a gasification reaction chamber, a double-stage bucket-shaped water-cooling jacket, a tilting grate, and a settling chamber. A carbon outlet auger is provided at the bottom of the settling chamber, a cone-shaped material extraction plate is provided on the lower inner side of the silo, and a cone-shaped ash plate is superimposed on the upper inner side of the double-stage bucket-shaped water-cooling jacket; the biomass fuel first undergoes a high-temperature cracking and gasification reaction in the gasification reaction chamber to generate combustion gas, and the combustion gas is discharged downward at the combustion gas outlet on the side wall of the settling chamber; the biomass fuel that has not completely reacted to generate combustion gas in the gasification reaction chamber is carbonized and falls into the settling chamber and is cooled to form biomass carbon, thereby allowing the biomass fuel to simultaneously achieve carbon-gas co-production.

[0011] For example, the invention with announcement number CN107083257B provides a biomass gasification system, including: a gasification furnace, which includes a furnace body and a material-dropping pipe, the furnace body includes an air outlet, a grate, and a feed port, the air outlet is arranged on the side wall of the furnace body, the grate is arranged at the bottom of the furnace body, an air inlet is arranged thereon, and the material-dropping pipe is arranged at the top of the furnace body corresponding to the feed port; the feeding device includes a storage bin, a feeding pipe, a material-pickling mechanism, a first sealing door, a second sealing door, and a sealing assembly, the feeding pipe is arranged at the top of the storage bin, the first sealing door is arranged on the feeding pipe, the material-pickling mechanism is installed at the bottom of the storage bin, the second sealing door is arranged corresponding to the material-dropping pipe, a driving rod is arranged thereon, a sealing cover is arranged on the driving rod, the sealing cover includes an upper end face and a side wall, and a small hole is opened on the upper end face; the sealing assembly includes a water tank arranged on the storage bin, a channel for passing the driving rod is arranged in the water tank, the channel is tubular, and the sealing cover covers the outside of the channel.

[0012] The above technical solutions all adopt the conventional gasification furnace layout of oxidation layer, reduction layer, cracking layer and drying layer. However, it is found in application that since the gasifying agent is generally oxygen-containing room temperature air, which is introduced into the gasification zone from the lower part of the grate, the combustion reaction is difficult to control, and the temperature is often too high (generally at 1000°C) and exceeds the optimal precipitation temperature of the biomass combustible gas, which ultimately affects the precipitation effect of the combustible gas; and the conventional gasifier requires a high-power fan to extract the gas continuously, which consumes a lot of energy. Summary of the invention

[0013] The object of the present invention is to provide an oxygen-free medium-temperature downdraft pyrolysis device.

[0014] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0015] An oxygen-free medium-temperature downdraft pyrolysis device comprises a pyrolysis furnace, a grate is arranged in the pyrolysis furnace, a feed port is arranged at the pyrolysis furnace above the grate, a closed feeder is arranged at the feed port, a discharge port is arranged at the pyrolysis furnace below the grate, a closed discharger is arranged at the discharge port,

[0016] The invention also includes an oxygen-free medium-temperature gas source mechanism which is arranged outside the pyrolysis furnace and supplies flue gas to the pyrolysis furnace. The oxygen-free medium-temperature gas source mechanism includes a burner. The inlet of the burner is connected to an input pipeline for supplying gas to the burner. The gas burns in the burner to produce flue gas. The outlet of the burner is connected to a flue gas output pipeline. The flue gas delivery pipeline is introduced into the pyrolysis furnace and is located above the grate and adjacent to the top of the pyrolysis furnace.

[0017] The pyrolysis furnace is provided with a combustible gas collector below the grate to form a downdraft structure; the combustible gas collector is guided outward to the outside of the pyrolysis furnace through a gas collecting pipeline.

[0018] The gas collection pipeline is sequentially connected with a dust collector, a cooler and a conveying fan.

[0019] The cooler is provided with multiple stages, and the multiple stages of coolers are sequentially connected in series on the gas collection pipeline to form a multi-stage cooling mechanism.

[0020] The burner is connected with an air supply fan.

[0021] The grate is an active grate, which includes a plurality of furnace rollers arranged horizontally and side by side. The furnace rollers are adjacent to each other and are grouped in pairs. The two furnace rollers in the same group rotate towards each other and rotate away from each other alternately.

[0022] The surface of the furnace roller is provided with material shifting teeth arranged along the circumferential direction.

[0023] The closed feeder includes a feed barrel connected to a feed port, the cross section of the feed barrel is a rectangular structure, two horizontally arranged feed rollers are arranged tangentially up and down in the feed barrel, the feed rollers are matched with the feed barrel and sealed, and axially extending feed grooves are arranged circumferentially on the feed rollers.

[0024] The enclosed discharger is a screw conveyor connected to the discharge port and arranged horizontally.

[0025] A distributor is provided in the pyrolysis furnace below the feed inlet.

[0026] The temperature of the flue gas produced by combustion in the burner is 570-600°C.

[0027] The beneficial effects of the present invention are:

[0028] 1. The oxygen-free medium-temperature flue gas with a temperature of about 570-600°C generated by the burner of the present invention provides an oxygen-free medium-temperature heat source for the pyrolysis furnace, and forms a medium-temperature (570-600°C) temperature field in the pyrolysis furnace, which can effectively control the precipitation temperature, ensure that the biomass in the pyrolysis furnace is at the optimal precipitation temperature for the precipitation of combustible gas, and thus ensure the precipitation effect of the combustible gas. Since the medium-temperature (570-600°C) temperature field is formed in the pyrolysis furnace, the temperature of the precipitated combustible gas is relatively low, reducing the difficulty of subsequent cooling treatment.

[0029] The flue gas conveying pipeline is introduced into the pyrolysis furnace and is located above the grate. The pyrolysis furnace is provided with a combustible gas collector below the grate, thereby forming a downdraft structure. Under the suction of the combustible gas collector, the raw material is gradually oxygen-free and medium-temperature thermally decomposed from top to bottom to separate the volatile combustible gas. At the same time, the precipitated gas enters the gas collecting pipeline from the combustible gas collector 7 under the suction of the conveying fan and is discharged to the outside of the pyrolysis furnace, and is subjected to dust removal and cooling treatment in turn.

[0030] And because pyrolysis is a pressure-boosting process, the conveying fan suction power requirement is relatively small, which reduces energy consumption and improves work efficiency. At the same time, the conveying fan suction power is relatively small, and the precipitated combustible gas carries less dust when it is discharged to the outside, reducing the difficulty of subsequent purification treatment.

[0031] At the same time, since the pyrolysis furnace is provided with an oxygen-free medium-temperature heat source, the carbon in the biomass basically does not participate in the reaction, the calorific value of the combustible gas released is high, and the slag after the combustible gas is released is a carbon slag, which falls from the grate to the discharge port and is discharged through a closed discharger and can be reused.

[0032] 2. The grate of the present invention adopts an active grate, which includes a plurality of furnace rollers arranged horizontally side by side. The furnace rollers are adjacent to each other in pairs and rotate towards and away from each other alternately in time, which can realize active discharge and ensure the uniformity of discharge.

[0033] 3. In the present invention, a closed feeder is provided at the feed inlet, and a closed discharger is provided at the discharge outlet, thereby ensuring the sealing effect in the pyrolysis furnace.

[0034] 4. In the present invention, a cooler is provided on the gas collection pipeline, and the cooler is provided with multiple stages. The multiple coolers are sequentially connected in series on the gas collection pipeline to form a multi-stage cooling mechanism. After cooling by the cooler, dry combustible gas at about 80° C. is obtained for standby use. Meanwhile, during the cooling process, the chemical substances in the combustible gas are dissolved in the liquid to form chemical products such as wood vinegar. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic diagram of the present invention;

[0036] Figure 2 is a schematic diagram of a closed feeder in the present invention;

[0037] Figure 3 It is a schematic diagram of the active grate in the present invention rotating towards each other;

[0038] Figure 4 It is a schematic diagram of the active grates in the present invention rotating in opposite directions. DETAILED DESCRIPTION

[0039] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, an oxygen-free medium-temperature downdraft pyrolysis device of the present invention comprises a pyrolysis furnace 1, a grate 2 is arranged in the pyrolysis furnace 1, a feed port is arranged at the pyrolysis furnace 1 above the grate 2, a closed feeder 3 is arranged at the feed port, a slag bin 4 is formed at the pyrolysis furnace 1 below the grate 2, a discharge port is arranged downwardly in the slag bin, and a closed discharger 5 is arranged at the discharge port.

[0041] like Figure 2 As shown, in this embodiment, the closed feeder 3 includes a feed barrel 31 connected to the feed port, the cross section of the feed barrel 31 is a rectangular structure, and two horizontally arranged feed rollers 32 are tangentially arranged in the feed barrel 31, and the feed rollers 32 match and seal the feed barrel 31. Axially extending material grooves 33 are arranged circumferentially on the feed rollers 31, and the feed barrel 31 is connected to a feed hopper 34 upward, thereby realizing closed feeding. A distributor 35 is provided below the feed port in the pyrolysis furnace 1 to achieve uniform material distribution.

[0042] In this embodiment, the closed discharger 5 is a screw conveyor connected to the discharge port and arranged horizontally.

[0043] The cooperation of the closed feeder 3 and the closed discharger 4 in the present invention ensures the sealing effect in the pyrolysis furnace.

[0044] like Figure 3 and Figure 4 As shown, the grate 2 is an active grate, which includes a plurality of furnace rollers arranged horizontally side by side. The surfaces of the furnace rollers 21 are provided with material-selecting teeth 22 arranged circumferentially. The furnace rollers 21 are arranged in groups of two adjacent to each other, and the two furnace rollers in the same group rotate towards and away from each other alternately in time.

[0045] Taking six furnace rollers as an example, they are divided into three groups and form five discharge gaps. When the two furnace rollers rotate towards each other, the discharge gaps one, three and five discharge materials downward, and the discharge gaps two and four turn materials upward; when the two furnace rollers rotate away from each other, the discharge gaps one, three and five turn materials upward, and the discharge gaps two and four discharge materials downward. This alternating process realizes active discharge and ensures uniformity of discharge.

[0046] The present invention also includes an oxygen-free medium-temperature gas source mechanism that is arranged outside the pyrolysis furnace 1 and supplies flue gas to the pyrolysis furnace 1. The oxygen-free medium-temperature gas source mechanism includes a burner 6. The inlet of the burner 6 is connected to an input pipeline 61 for supplying gas to the burner. The burner is also connected to an air supply fan 63. The gas burns in the burner 6 to produce oxygen-free medium-temperature flue gas (the flue gas temperature is 570-600°C, preferably about 600°C). The outlet of the burner 6 is connected to a flue gas output pipeline 62. The flue gas delivery pipeline 62 is introduced into the pyrolysis furnace and is located above the grate 2 and adjacent to the top of the pyrolysis furnace 1. In this embodiment, the end of the flue gas delivery pipeline 62 is located below the top indicator line 11 of the material layer in the pyrolysis furnace 1.

[0047] The pyrolysis furnace 1 is provided with a combustible gas collector 7 below the grate, forming a downdraft structure. The combustible gas collector 7 is led out to the outside of the pyrolysis furnace 1 through a gas collecting pipe 71, and the gas collecting pipe is sequentially connected with a dust collector 8, a cooler 9 and a conveying fan 10. The precipitated gas enters the gas collecting pipe 71 from the combustible gas collector 7 under the suction force of the conveying fan 10 and is discharged to the outside of the pyrolysis furnace 1, and is subjected to dust removal and cooling treatment in sequence.

[0048] In this embodiment, the cooler 9 is a shell-and-tube cooler, and the cooler 9 is provided with four stages. The four-stage coolers are sequentially connected in series on the gas collection pipeline to form a multi-stage cooling mechanism.

[0049] The working principle of the present invention is as follows: biomass (garbage, sludge, rubber, etc.) enters the pyrolysis furnace 1 from the closed feeder 3, and the material layer indicator line formed is as follows: Figure 1 As shown in Figure 11.

[0050] The oxygen-free medium-temperature flue gas with a temperature of about 570-600°C generated by the burner 6 provides an oxygen-free medium-temperature heat source for the pyrolysis furnace 1, and forms a medium-temperature (570-600°C) temperature field in the pyrolysis furnace 1, which can effectively control the precipitation temperature, ensure that the biomass in the pyrolysis furnace is at the optimal precipitation temperature for the precipitation of combustible gas, and thus ensure the precipitation effect of the combustible gas. Since a medium-temperature (570-600°C) temperature field is formed in the pyrolysis furnace 1, the temperature of the precipitated combustible gas is also relatively low (about 300°C), reducing the difficulty of subsequent cooling treatment.

[0051] Due to the down-suction structure, under the suction of the combustible gas collector 7, the raw material is gradually decomposed from top to bottom without oxygen and at a medium temperature to remove the volatile components of the combustible gas. At the same time, the precipitated gas enters the gas collection pipeline 71 from the combustible gas collector 7 under the suction of the conveying fan 10 and is discharged to the outside of the pyrolysis furnace 1, and is subjected to dust removal and cooling treatment in turn. The precipitated gas is cooled by the cooler 9 to obtain a dry combustible gas at about 80°C for standby use. At the same time, during the cooling process, the chemical substances in the combustible gas are dissolved in the liquid to form chemical products such as wood vinegar.

[0052] And because pyrolysis is a pressure-boosting process, the conveying fan 10 has a smaller suction power requirement, which reduces energy consumption and improves work efficiency. At the same time, the conveying fan has a smaller suction power, and the precipitated combustible gas carries less dust when it is discharged to the outside, reducing the difficulty of subsequent purification treatment.

[0053] And because the pyrolysis furnace 1 is provided with an oxygen-free medium-temperature heat source, the carbon in the biomass basically does not participate in the reaction, the calorific value of the combustible gas released is high, and the slag after the combustible gas is released is carbon slag, which falls through the grate to the discharge port and is discharged through the closed discharger 5 for reuse.

[0054] The present invention is completely different from the conventional gasification furnace layout and principle, and effectively ensures that the biomass in the pyrolysis furnace is at the optimal precipitation temperature for precipitating combustible gas, thereby ensuring the precipitation effect of the combustible gas and realizing comprehensive resource processing.

[0055] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0056] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "front", "rear", "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the protection content of the present invention.

Claims

1. An oxygen-free medium-temperature downdraft pyrolysis device, comprising a pyrolysis furnace, a grate is arranged in the pyrolysis furnace, a feed port is arranged at the pyrolysis furnace above the grate, a closed feeder is arranged at the feed port, a discharge port is arranged at the pyrolysis furnace below the grate, a closed discharger is arranged at the discharge port, and the characteristics are: The invention also includes an oxygen-free medium-temperature gas source mechanism which is arranged outside the pyrolysis furnace and supplies flue gas to the pyrolysis furnace. The oxygen-free medium-temperature gas source mechanism includes a burner. The inlet of the burner is connected to an input pipeline for supplying gas to the burner. The gas burns in the burner to produce flue gas. The outlet of the burner is connected to a flue gas output pipeline. The flue gas delivery pipeline is introduced into the pyrolysis furnace and is located above the grate and adjacent to the top of the pyrolysis furnace. The temperature of the flue gas produced by combustion in the burner is 570-600°C; the pyrolysis furnace is provided with a combustible gas collector below the grate to form a downdraft structure; The combustible gas collector is led out to the outside of the pyrolysis furnace through a gas collection pipeline; The grate is an active grate, which includes a plurality of furnace rollers arranged horizontally side by side, the furnace rollers are adjacent to each other in a group of two, and the two furnace rollers in the same group rotate towards each other and rotate away from each other alternately; A distributor is provided in the pyrolysis furnace below the feed inlet.

2. The anaerobic medium-temperature downdraft pyrolysis device according to claim 1 is characterized in that: The gas collection pipeline is sequentially connected with a dust collector, a cooler and a conveying fan.

3. The anaerobic medium-temperature downdraft pyrolysis device according to claim 2 is characterized in that: The cooler is provided with multiple stages, and the multiple stages of coolers are sequentially connected in series on the gas collection pipeline to form a multi-stage cooling mechanism.

4. The anaerobic medium-temperature downdraft pyrolysis device according to claim 1, characterized in that: The burner is connected with an air supply fan.

5. The anaerobic medium-temperature downdraft pyrolysis device according to claim 1, characterized in that: The surface of the furnace roller is provided with material shifting teeth arranged along the circumferential direction.

6. The anaerobic medium-temperature downdraft pyrolysis device according to claim 1, characterized in that: The closed feeder includes a feed barrel connected to a feed port, the cross section of the feed barrel is a rectangular structure, two horizontally arranged feed rollers are arranged tangentially up and down in the feed barrel, the feed rollers are matched with the feed barrel and sealed, and axially extending feed grooves are arranged circumferentially on the feed rollers.

7. The anaerobic medium-temperature downdraft pyrolysis device according to claim 1, characterized in that: The enclosed discharger is a screw conveyor connected to the discharge port and arranged horizontally.

Images