Biomass gasifier applied to ardealite calcination process

Abstract

The utility model discloses a biomass gasification furnace applied to an ardealite calcination process, relates to the field of ardealite production and calcination, and aims to solve the problem that the temperature in the existing biomass gasification furnace is unstable and cannot meet the requirement of the ardealite calcination temperature. A feeding pipe is arranged in the furnace body, a pyrolysis and gasification cavity is formed in the furnace body and communicated with the feeding pipe, a movable material bed is arranged in the pyrolysis and gasification cavity, an inclined supporting frame is fixedly connected to the lower portion of the movable material bed, one end of the movable material bed is located under the feeding pipe, and a fire guide pipe is arranged on the side edge of the other end of the movable material bed; the biomass gasification furnace has the advantages that through innovation of the furnace body structure and the movable material bed, multi-parameter cooperative control and process adaptive transformation, the stability of the temperature in the biomass gasification furnace is improved, and the requirements of phosphogypsum calcination can be met.

Description

Technical Field

[0001] This utility model relates to the field of calcination technology for phosphogypsum production, and in particular to a biomass gasification furnace applied to the calcination process of phosphogypsum. Background Technology

[0002] As a byproduct of the phosphate chemical industry, the resource utilization of phosphogypsum is key to achieving the industry's green transformation. Traditional pulverized coal furnaces have shortcomings in terms of energy cost and environmental pollution, while biomass gasification furnaces, although inexpensive and carbon-neutral, suffer from uneven internal temperature leading to excessive thermal nitrogen oxides (NOx) and are difficult to meet the precise temperature control requirements for phosphogypsum calcination.

[0003] Biomass gasification furnaces primarily use waste agricultural and forestry materials such as straw, stalks, sawdust, and wood shavings, compressed into biomass pellets as fuel. The pellets undergo pyrolysis and gasification to produce carbon monoxide, hydrogen, and small amounts of methane and hydrocarbons. After secondary, rationally distributed air combustion, the gasification process improves thermal efficiency, saving over 20% more energy than traditional stoker combustion. The smoke and waste generated during combustion meet relevant national air emission standards. This effectively saves energy, enables the efficient and environmentally friendly utilization of waste resources, helps maintain atmospheric CO2 balance, mitigates the global greenhouse effect, and significantly promotes the construction of a resource-saving society.

[0004] Existing biomass gasifiers have low pyrolysis and gasification of raw materials, and uneven temperature in the combustion zone within the furnace. Phosphogypsum calcination requires maintaining a stable temperature field at 880-920℃, but the temperature fluctuation range within existing biomass gasifiers reaches ±100℃. The localized high temperature inside leads to the generation of thermal nitrogen oxides, polluting the environment. Utility Model Content

[0005] In view of the above situation and to overcome the defects of the prior art, this utility model provides a biomass gasification furnace for the calcination process of phosphogypsum. This design effectively solves the problem that the internal temperature of the existing biomass gasification furnace is unstable and cannot meet the calcination temperature requirements of phosphogypsum.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention includes a feed pipe, a furnace body is fixedly connected below the feed pipe, a pyrolysis gasification chamber is provided inside the furnace body, the pyrolysis gasification chamber is connected to the feed pipe, a movable material bed is provided inside the pyrolysis gasification chamber, an inclined support frame is fixedly connected below the movable material bed, one end of the movable material bed is located directly below the feed pipe, a fire guide pipe is provided on the side of the other end of the movable material bed, and a temperature control component and an airflow control component are provided inside the furnace body;

[0007] The temperature control component includes: a multi-zone temperature sensor array set in the pyrolysis gasification chamber, and the temperature sensor array is connected to the central controller;

[0008] The airflow control components include: variable frequency fan unit, wind speed sensor and dynamic air pressure regulating valve, which form a closed-loop control circuit;

[0009] The central controller is based on the calcination temperature requirements of phosphogypsum and establishes a three-dimensional control model of temperature, wind speed, and wind pressure.

[0010] Preferably, the pyrolysis gasification chamber includes a bottom oxidation zone, a middle reduction zone, and an upper drying zone. The furnace body is provided with air supply channels that are respectively connected to the three zones, and the air supply channels realize temperature gradient control for the three zones.

[0011] Preferably, the variable frequency fan unit includes multiple fans with different power outputs, the dynamic air pressure regulating valve is connected to a pressure feedback device, and the wind speed sensor is a thermal anemometer.

[0012] Preferably, the bottom oxidation zone is connected to a secondary air supply system.

[0013] Preferably, the upper end of the feed pipe is connected to a hopper, the feed pipe is provided with an upper feed chamber and a lower feed chamber, the furnace body is provided with a slag outlet, and the slag outlet is located below the end of the movable material bed.

[0014] Preferably, an adjustment gate is provided between the upper feeding chamber and the lower feeding chamber, and the adjustment gate is used to adjust the feeding rate.

[0015] Compared with the prior art, the outstanding advantages of this utility model are:

[0016] This invention features an inclined movable bed of materials inside the pyrolysis gasification chamber. The movable bed moves the upper biomass material downwards, and the biomass in the upper drying zone is transferred to the lower bottom oxidation zone, allowing for timely replenishment of materials in the bottom drying zone and ensuring a stable temperature supply to the ignition tube from the bottom drying zone.

[0017] This invention includes a temperature control component, an airflow control component, and a three-dimensional control model installed inside the furnace. By controlling the temperature, wind speed, and wind pressure, the temperature inside the furnace is kept within the range that meets the requirements for phosphogypsum calcination, thus ensuring the quality of phosphogypsum calcination. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall front cross-sectional structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the structure on the right side of this utility model.

[0020] Figure 3 This is a top view of the structure of this utility model.

[0021] The following are labeled in the diagram: 1. Feed pipe; 2. Furnace body; 3. Pyrolysis gasification chamber; 4. Movable material bed; 5. Inclined support frame; 6. Fire guide pipe; 7. Air supply channel; 8. Slag outlet. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see the appendix Figure 1-3 This embodiment describes a biomass gasification furnace applied to the calcination process of phosphogypsum: it includes a feed pipe 1, a furnace body 2 fixedly connected below the feed pipe 1, a pyrolysis gasification chamber provided inside the furnace body 2, the pyrolysis gasification chamber communicating with the feed pipe 1, a movable material bed 4 provided inside the pyrolysis gasification chamber, an inclined support frame 5 fixedly connected below the movable material bed 4, one end of the movable material bed 4 located directly below the feed pipe 1, and a fire guide pipe 6 provided on the side of the other end of the movable material bed 4. The furnace body 2 is provided with a temperature control component and an airflow control component.

[0024] Feed pipe 1 is located on one side above furnace body 2. Feed pipe 1 and furnace body 2 are two relatively independent structures. The adjustment gate installed inside feed pipe 1 is used to regulate the amount of plastic fed into furnace body 2. The adjustment gate is made of high-temperature resistant alloy material and is driven by a servo motor to achieve stepless adjustment of the feeding rate within the range of 5-20 kg / min. The pyrolysis gasification chamber is divided into three temperature control zones: bottom oxidation zone: located at the bottom 1 / 3 height of furnace body 2, equipped with a combustion chamber built of refractory bricks; middle reduction zone: located at the middle 1 / 3 height of furnace body 2, equipped with a porous baffle to promote gas mixing; upper drying zone: located at the top 1 / 3 height of furnace body 2. The temperature of the above three zones is controlled in a gradient, with the upper drying zone having the lowest temperature: controlled at 400-600℃; the middle reduction zone: maintained at 700-800℃. Bottom oxidation zone: Maintaining a high temperature of 850-950℃, the movable bed 4 is placed obliquely in the pyrolysis gasification chamber. The movable bed 4 guides the movement of biomass fuel, gradually transporting the biomass fuel from the upper drying zone to the bottom oxidation zone below, thus ensuring that there is enough biomass fuel to replenish the bottom oxidation zone. This keeps the temperature in the pyrolysis gasification chamber constant. The heat from combustion is connected to the phosphogypsum calcining furnace through the ignition pipe 6. This stable heat is used to calcine the phosphogypsum, overcoming the problem of uneven heat distribution in traditional biomass fuels, which prevents their application in phosphogypsum calcination.

[0025] The temperature control component is equipped with a multi-zone temperature sensor array in the pyrolysis gasification chamber, including three K-type thermocouples in the bottom oxidation zone, evenly distributed on the side wall of the combustion chamber; two platinum resistance thermometers in the middle reduction zone, located above and below the porous partition; and one infrared thermometer in the upper drying zone, positioned 0.5m below the feed inlet. All temperature data are transmitted to the central controller via a 4-20mA signal. The controller uses a Siemens S7-1500 series PLC with a built-in fuzzy PID control algorithm.

[0026] The variable frequency fan unit within the airflow control module consists of two centrifugal fans with rated powers of 15kW and 7.5kW respectively, and their speeds are adjusted via a frequency converter. The air pressure regulating valve is installed in the main air duct and is equipped with a pressure sensor (range 0-2000Pa, accuracy ±1%) and an electric actuator. The wind speed sensor is a thermal anemometer, installed at the end of each air supply branch pipe, with a measurement range of 0-5m / s.

[0027] The central controller has a built-in three-dimensional control model and uses the LabVIEW software platform to achieve the following functions: real-time display and historical data storage of temperature, wind speed and wind pressure parameters; expert system database stores the optimal process parameters of five common biomass materials such as Juncao, corn stalks and sawdust; remote monitoring interface supports TCP / IP protocol, and control strategies can be adjusted through a host computer.

[0028] When this system is used for phosphogypsum calcination, the initial stage involves setting the feed rate to 10 kg / min using an adjustable gate valve, activating the liquefied gas ignition device in the bottom oxidation zone, preheating the furnace body 2, and maintaining it at a specific temperature for a period of time. During operation, the target temperature in the bottom oxidation zone is 900℃, and the main air volume is adjusted to 1200 m³ / h using a variable frequency fan unit. The target temperature in the middle reduction zone is 750℃, air is injected through the ducts in the secondary air supply system, and the target temperature in the upper drying zone is 500℃. A zirconia oxygen analyzer is installed in the bottom oxidation zone to monitor the oxygen content in real time and maintain it at a specific level. When the oxygen content is lower than the standard value, the main air supply is increased; when it is higher than the standard value, the air supply is reduced. Additionally, the NOx concentration needs to be detected and controlled. When the NOx concentration exceeds 100 ppm, the following operations are performed:

[0029] Reduce the air supply to the bottom oxidation zone;

[0030] Increase the temperature in the central reduction zone to 780℃;

[0031] Adjust the jet angle of the air duct in the secondary air supply system to increase the air supply to the middle reduction zone and decrease the air supply to the bottom oxidation zone, thereby rapidly increasing the temperature in the middle reduction zone.

[0032] Termination stage: After calcination is completed, gradually reduce the speed of the variable frequency fan unit to 300m³ / h; maintain the negative pressure in the furnace at -50Pa, and discharge the residual gas into the alkaline washing tower for treatment by the induced draft fan, and discharge the calcination residue of biomass from the slag outlet 8.

[0033] Furthermore, to ensure that the biomass gasification furnace can provide a stable temperature for phosphogypsum calcination, this application is equipped with a three-level alarm mechanism, namely, abnormal temperature gradient warning, abnormal air supply pressure warning, and oxygen content deviation warning.

[0034] Temperature gradient anomaly

[0035] When the temperature difference between adjacent temperature zones exceeds the set value by 20% (e.g., the temperature difference between the bottom oxidation zone and the middle reduction zone > 200℃), the central controller triggers a yellow alarm and automatically performs the following measures:

[0036] The test gate closes the channel between the upper and lower feed chambers, pausing feeding for 5 minutes;

[0037] Increase the air supply to the central reduction zone by 10%;

[0038] Record abnormal data to the fault log.

[0039] abnormal air supply pressure

[0040] When the air pressure regulating valve detects that the pressure has been continuously below 300Pa for more than 5 minutes, a red alarm is triggered and the following actions are taken:

[0041] Switch to standby fan (7.5kW);

[0042] Close the regulating gate;

[0043] Notify maintenance personnel via SMS module.

[0044] Oxygen content deviation

[0045] When the oxygen content deviates from the set range of ±1.5 vol% for more than 10 minutes, an orange alarm is triggered and a compensation procedure is initiated.

[0046] Adjust the air volume distribution ratio between the main air duct and the secondary air supply system duct;

[0047] If the problem persists after compensation, reduce the feed rate to 8 kg / min.

[0048] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A biomass gasification furnace used in the calcination process of phosphogypsum, characterized in that: The furnace includes a feed pipe (1), a furnace body (2) is fixedly connected below the feed pipe (1), a pyrolysis gasification chamber is provided inside the furnace body (2), the pyrolysis gasification chamber is connected to the feed pipe (1), a movable material bed (4) is provided inside the pyrolysis gasification chamber, an inclined support frame (5) is fixedly connected below the movable material bed (4), one end of the movable material bed (4) is located directly below the feed pipe (1), a fire guide pipe (6) is provided on the side of the other end of the movable material bed (4), and a temperature control component and an airflow control component are provided inside the furnace body (2). The temperature control component includes: a multi-zone temperature sensor array set in the pyrolysis gasification chamber, and the temperature sensor array is connected to the central controller; The airflow control components include: variable frequency fan unit, wind speed sensor and dynamic air pressure regulating valve, which form a closed-loop control circuit; The central controller is based on the calcination temperature requirements of phosphogypsum and establishes a three-dimensional control model of temperature, wind speed, and wind pressure.

2. A biomass gasification furnace for use in the calcination process of phosphogypsum according to claim 1, characterized in that: The pyrolysis gasification chamber includes a bottom oxidation zone, a middle reduction zone and an upper drying zone. The furnace body (2) is provided with air supply channels (7) that are connected to the three zones respectively. The air supply channels (7) achieve temperature gradient control for the three zones.

3. A biomass gasification furnace for use in the calcination process of phosphogypsum according to claim 1, characterized in that: The variable frequency fan unit includes multiple fans with different power outputs. A pressure feedback device is connected to the dynamic air pressure regulating valve, and the wind speed sensor is a thermal anemometer.

4. A biomass gasification furnace applied to the calcination process of phosphogypsum according to claim 2, characterized in that: The bottom oxidation zone is connected to a secondary air supply system.

5. A biomass gasification furnace for use in the calcination process of phosphogypsum according to claim 1, characterized in that: The feed pipe (1) is connected to a hopper at the upper end. The feed pipe (1) is provided with an upper feed chamber and a lower feed chamber. The furnace body (2) is provided with a slag outlet (8). The slag outlet (8) is located below the end of the movable bed (4).

6. A biomass gasification furnace for use in the calcination process of phosphogypsum according to claim 5, characterized in that: An adjustment gate is provided between the upper feeding chamber and the lower feeding chamber, and the adjustment gate is used to adjust the feeding rate.

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