Tar incineration device and biomass raw material gasification system

Abstract

The application discloses a tar incineration device and a biomass raw material gasification system. The tar incineration device comprises a tar pool, a condensed water evaporator, a tar direct combustion furnace and an air heat exchanger. The tar is incinerated in the tar direct combustion furnace after passing through the tar pool and the condensed water evaporator. The tar direct combustion furnace generates flue gas. The flue gas passes through the air heat exchanger and the condensed water evaporator to realize the cascade utilization of heat. The biomass raw material gasification system comprises the tar incineration device and a gasification furnace. The tar direct combustion furnace is provided with a dual-fuel combustor. The closed loop process of tar pool mixing and viscosity reduction, condensed water evaporator quality improvement and tar direct combustion furnace high-temperature incineration realizes the harmless treatment and heat energy recovery of the tar. The dual-fuel combustor supports flexible switching of multiple fuels and can meet different requirements of multiple working conditions. The system constructs a closed loop energy chain of 'biomass raw material - synthesis gas + tar - heat energy recovery', maximizes the recovery of biomass energy and reduces the dependence on external fuels.

Description

Technical Field

[0001] This application relates to the field of tar treatment technology, and in particular to a tar incineration device and a biomass feedstock gasification system. Background Technology

[0002] Biomass gasification technology, as a highly efficient renewable energy conversion method, converts biomass feedstocks (such as straw and sawdust) into syngas (mainly composed of CO, H2, and CH4) through a thermochemical process, and is widely used in power generation, heating, and chemical raw material production. However, during the gasification process, incomplete pyrolysis of biomass feedstocks under oxygen-deficient or oxygen-deficient conditions generates tar (a viscous byproduct composed of complex hydrocarbons such as benzene, phenols, and polycyclic aromatic hydrocarbons). The presence of tar not only reduces the quality of syngas and causes coking and corrosion in downstream equipment (such as gas turbines and catalysts), but its direct emissions also cause serious environmental pollution, threatening the ecological environment and human health.

[0003] Existing tar treatment technologies have the following drawbacks:

[0004] 1. Each gasifier is independently equipped with an incineration or catalytic unit, which leads to a surge in equipment investment and operation and maintenance costs, and poor economic efficiency for small and medium-sized systems;

[0005] 2. During centralized treatment, tar is prone to solidification and blockage in pipelines due to its high viscosity (>1000cP), requiring frequent maintenance, and the accumulation of volatile organic compounds (VOCs) can cause safety hazards;

[0006] 3. Traditional incineration requires a large amount of diesel / natural gas for combustion, and low-temperature combustion also produces pollutants such as CO and polycyclic aromatic hydrocarbons (PAHs). Waste heat utilization is low, resulting in significant energy waste. Existing improvement solutions (such as heat tracing and insulation, and dilution and viscosity reduction) are limited by energy consumption, cost, or separation difficulties, making large-scale application challenging.

[0007] Therefore, there is an urgent need for a tar treatment technology that balances low cost, anti-clogging, and efficient and clean incineration. Summary of the Invention

[0008] The purpose of this application is to overcome the shortcomings of the existing technology and provide a tar incineration device and a biomass feedstock gasification system.

[0009] This application provides a tar incineration device, characterized in that it comprises: a tar pool for storing tar, wherein the tar can mix with condensate in the tar pool to form a first mixture that is convenient to flow in a pipeline; a condensate evaporator connected to the tar pool, wherein after the first mixture enters the condensate evaporator, the condensate therein is evaporated into water vapor, and the water vapor mixes with the tar to form a second mixture; a tar direct-fired furnace connected to the condensate evaporator, wherein the second mixture enters the tar direct-fired furnace and is incinerated to generate hot flue gas; an air heat exchanger connected to the tar direct-fired furnace, wherein the hot flue gas enters the air heat exchanger as a heat source for the air heat exchanger, wherein the hot flue gas can preheat air, and the obtained hot air can be used as a gasifying agent in a gasifier; and the flue gas, after passing through the air heat exchanger and completing one heat exchange, flows to the condensate evaporator as a heat source for the condensate evaporator.

[0010] Furthermore, the tar tank is equipped with: a temperature control mechanism for regulating the temperature of the first mixture in the tar tank to maintain the first mixture at 60-80°C; and / or a density sensor for monitoring the density of the first mixture to infer the ratio of tar to water; and / or a viscometer for monitoring the viscosity of the first mixture to ensure it meets the conveying requirements; and / or a stirrer for stirring the first mixture to prevent tar from settling and caking.

[0011] Furthermore, the tar incineration device also includes a first condenser, which is located on the heat source discharge pipeline of the condensate evaporator and is used to condense water vapor in the flue gas passing through the condensate evaporator to obtain condensate, which can be returned to the tar pool.

[0012] Furthermore, the tar incineration device also includes a second condenser, which is located on the heat exchanger discharge pipe of the condensate evaporator. The second condenser is used to condense the water vapor in the second mixture discharged through the condensate evaporator to obtain condensate, which can be returned to the tar pool. By diverting the flow through the second condenser, the proportion of water vapor in the second mixture can also be reduced, thereby preventing water vapor from interfering with the combustion of tar.

[0013] Furthermore, in the tar pool, the ratio of tar to water is 1:1 to 1:3; after the water vapor is diverted through the second condenser, it enters the second mixture in the tar direct-fired furnace, where the ratio of tar to water vapor is 2:1 to 3:1.

[0014] Furthermore, the tar incineration device also includes a water replenishment mechanism, which is used to increase the proportion of water in the first mixture; the water replenishment mechanism includes: a water preparation tank for supplying softened ordinary water; and a heater for preheating the ordinary water so that the temperature of the ordinary water is close to the temperature of the tar in the tar pool.

[0015] Furthermore, a heat tracing layer is provided outside the tar pool and / or the pipe connecting the tar pool to the condensate evaporator; the heat tracing layer is connected to the heat source discharge pipe of the condensate evaporator; the flue gas discharged from the condensate evaporator enters the heat tracing layer, which can maintain the temperature of the first mixture.

[0016] This application also provides a biomass feedstock gasification system, including the above-mentioned tar incineration device, and a gasifier. The gasifier can convert biomass feedstock into syngas through a high-temperature thermochemical reaction, and generate tar and water vapor as a byproduct. The tar direct-fired furnace is equipped with a dual-fuel burner, which can not only burn natural gas or diesel, but also burn the syngas generated by the gasifier and a second mixture.

[0017] Furthermore, the biomass feedstock gasification system also includes a third condenser, which is located on the gasifier's discharge pipeline and is used to cool the gasification products discharged from the gasifier, so that the tar and water vapor in the gasification products are condensed into liquid; the condensed tar and condensate enter the tar pool.

[0018] Furthermore, the condensation temperature of the third condenser is 80-150℃ to separate the syngas from the gasification products and to condense the tar and water vapor into a liquid state; the temperature of the first mixture in the tar pool is maintained at 60-80℃ to prevent the tar from solidifying and to ensure the fluidity of the first mixture; the operating temperature of the condensate evaporator is 100-120℃ to ensure that the water in the first mixture is completely evaporated and that some of the light components in the tar are vaporized, while the heavy components remain liquid; the combustion temperature of the tar direct-fired furnace is 1000-1200℃; the temperature of the hot flue gas discharged from the tar direct-fired furnace is 600-800℃, the hot flue gas enters the air heat exchanger, and after one heat exchange, it is cooled to 400-500℃, the air is preheated to 300-450℃, and the cooled flue gas enters the condensate evaporator, and after a second heat exchange, it is cooled to 80-150℃.

[0019] This application provides a tar incineration device, including a tar pool, a condensate evaporator, a tar direct-fired furnace, and an air heat exchanger. Tar passes sequentially through the tar pool and the condensate evaporator before finally entering the tar direct-fired furnace for incineration. The tar direct-fired furnace generates flue gas, which passes sequentially through the air heat exchanger and the condensate evaporator, achieving cascaded energy utilization through heat exchange. The tar incineration device provided by this application mixes tar and condensate to form a first mixture with better fluidity, avoiding pipe blockage and pumping difficulties caused by the high viscosity of tar, thus ensuring the stability of system operation. The condensate evaporator evaporates the water in the first mixture to form a second mixture that is easily atomized. Combined with the high-temperature incineration process of the tar direct-fired furnace, this improves combustion efficiency and reduces emissions of pollutants such as black smoke and polycyclic aromatic hydrocarbons, achieving clean incineration. At the same time, the hot flue gas sequentially exchanges heat with the air and the first mixture twice, utilizing waste heat in a cascaded manner, reducing external energy consumption and improving the system's energy efficiency. Furthermore, the tar incineration device provided in this application can be used in conjunction with gasifiers, carbonization furnaces, etc., enabling centralized tar treatment, reducing equipment investment and maintenance costs, and enhancing compatibility with multiple equipment scenarios.

[0020] This application also provides a biomass feedstock gasification system, including the aforementioned tar incineration device and a gasifier, wherein the direct-fired tar furnace is equipped with a dual-fuel burner. By integrating the tar incineration device and the dual-fuel burner, the system effectively solves the problems of difficult tar treatment, poor fuel adaptability, and high dependence on external energy in traditional biomass gasification. The system achieves harmless treatment and heat recovery of tar through a closed-loop process of tar pool mixing and viscosity reduction, condensate evaporator upgrading, and high-temperature combustion in the direct-fired tar furnace, avoiding tar blockage of pipelines and environmental pollution. The dual-fuel burner supports natural gas, diesel, and synthetic fuels. The system allows for flexible switching between multiple fuels, including biomass gas and tar, to meet the diverse needs of various operating conditions, such as startup, low load, and normal operation. Simultaneously, the dual-fuel burner utilizes the high reactivity of syngas to promote tar cracking and improve combustion efficiency through multi-fuel syngas co-combustion, further cleaning residual impurities during syngas combustion. The system constructs a closed-loop energy chain of "biomass feedstock → syngas + tar → heat recovery," maximizing biomass energy recovery, reducing dependence on external fuels, and lowering overall energy consumption through waste heat cascade utilization, thus achieving a stable, environmentally friendly, and economical biomass gasification process. Attached Figure Description

[0021] Figure 1 A schematic diagram of a biomass feedstock gasification system provided in this application;

[0022] Figure 2 A schematic diagram of a gasification product processing flow provided in this application;

[0023] Figure 3 This is a schematic diagram of a cascade utilization of flue gas waste heat provided for this application. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] This application provides a tar incineration device, comprising: a tar pool 1 for storing tar, wherein the tar can mix with condensate in the tar pool 1 to form a first mixture that is convenient to flow in a pipeline; a condensate evaporator 2 connected to the tar pool 1, wherein after the first mixture enters the condensate evaporator 2, the condensate in the evaporator 2 is evaporated into water vapor, and the water vapor and tar form a second mixture; a tar direct-fired furnace 3 connected to the condensate evaporator 2, wherein the second mixture enters the tar direct-fired furnace 3 and is incinerated to generate hot flue gas; an air heat exchanger 4 connected to the tar direct-fired furnace 3, wherein the hot flue gas enters the air heat exchanger 4 as a heat source for the air heat exchanger 4, wherein the hot flue gas can preheat air, and the obtained hot air can be used as a gasifying agent in a gasifier; and the flue gas, after completing one heat exchange in the air heat exchanger 4, flows to the condensate evaporator 2 as a heat source for the condensate evaporator 2.

[0026] Specifically, tar pool 1 is used to hold tar and water. The water is primarily condensate, which is a liquid formed when water vapor contained in high-temperature gas condenses below its dew point during the cooling process. In this application, the high-temperature gas is generated by a gasification system, specifically flue gas and syngas. Therefore, the condensate in this application is a product of the gasification system and can be recycled. In actual use, when the amount of condensate is insufficient, the water can also be other liquids that are easy to mix with tar and can improve the fluidity of the tar (such as deionized water, softened water, etc.).

[0027] The tar incineration device provided in this application can be used in conjunction with equipment that produces tar, such as gasifiers and carbonization furnaces, or it can be set up independently for the purpose of treating tar.

[0028] Figure 1 In the illustrated embodiment, the tar incineration device is used in conjunction with at least one set of gasifiers. After the gasifiers process the biomass feedstock, they produce tar, which is then fed into tar tank 1 and mixed with water to form a first mixture.

[0029] It's important to explain that coal tar has a high viscosity at room temperature (reaching over 1000 mPa·s), resulting in extremely poor flowability. Direct pumping of this tar can easily clog pipelines. Mixing tar with water allows the water to act as a diluent, reducing the viscosity of the tar (e.g., a 1:1 mixture of tar and water can reduce viscosity by over 50%). Simultaneously, the presence of water helps the first mixture form an "oil-in-water" dispersion system within the pipeline, reducing direct adhesion between the tar and the pipe walls. Furthermore, the addition of water lowers the ignition point of the tar (from 580°C to 480°C), shortening preheating time before combustion and saving energy.

[0030] In tar pool 1, condensate is preferably mixed with tar.

[0031] This is because the condensate originates from the cooling and condensation of water vapor in the syngas or flue gas within the system (details below), and its composition is naturally compatible with tar. Since the condensate often contains trace amounts of tar components (such as benzene, toluene, and other light aromatics) during its formation, it is more likely to form a homogeneous and stable solution with tar through intermolecular forces, rather than the traditional oil-water emulsion, thus reducing the risk of stratification. This homogeneity also helps maintain the stability of the first mixture in tar pool 1 and the pipelines over a long period, avoiding pump blockage or uneven evaporation caused by stratification.

[0032] Secondly, the temperature characteristics of the condensate are highly compatible with those of the tar. The condensate temperature in the system is typically 80~150℃ (e.g., the condensate discharged from the third condenser 7 is about 80℃, and the condensate returning from the second condenser 6 is about 100℃), which is close to the 60~80℃ temperature range maintained in the tar pool 1. This avoids the phenomenon of localized sudden condensation and solidification of tar caused by excessive temperature differences in traditional makeup water (e.g., 20℃ ambient temperature tap water), ensuring a smooth and stable mixing and transportation process.

[0033] Furthermore, condensate, as a system byproduct, can be directly used to dilute tar without additional treatment. This avoids the introduction of minerals such as calcium and magnesium ions from external water sources, whose hardness is typically >100 ppm. If these ions react with phenolic acidic substances in the tar, they will form insoluble precipitates such as calcium phenolate, which can easily clog pipes and valves over time. Condensate hardness <5 ppm eliminates the risk of scaling at the source.

[0034] The preferred method of mixing condensate and tar not only utilizes the natural compatibility of resources within the system, but also addresses the shortcomings of traditional water replenishment methods through temperature matching and water quality optimization.

[0035] In the gasification system provided in this application, the condensate mainly comes from three sources: first, the water vapor in the gasification products generated by the gasifier is cooled by the third condenser 7 and condenses into liquid water as the temperature drops below the dew point; second, the water vapor in the high-temperature flue gas generated by the tar direct combustion furnace 3 is condensed and precipitated after passing through the first condenser 5; and third, the excess water vapor that does not enter the tar direct combustion furnace 3 and participates in combustion is condensed after being cooled by the second condenser 6 through the condensate evaporator 2 (see below for details).

[0036] This allows the condensate to flow into tar pool 1, mix with tar, and form a first mixture, thus realizing the recycling of water resources within the system.

[0037] Continue to refer to Figure 1 The condensate evaporator 2 is connected to the tar tank 1 via a pipeline. A centrifugal pump is installed on the pipeline, which, driven by mechanical energy, transports the first mixture in the tar tank 1 to the condensate evaporator 2. The condensate evaporator 2 heats the first mixture by heat exchange at a temperature higher than 100°C, causing the water in the first mixture to evaporate into water vapor, and the tar and water vapor to form a second mixture.

[0038] It needs to be explained that the first mixture is not directly burned because untreated tar has high viscosity and complex composition (containing heavy components such as polycyclic aromatic hydrocarbons). Direct combustion results in poor atomization and incomplete combustion due to uneven mixing, producing black smoke and pollutants such as polycyclic aromatic hydrocarbons. After the water is evaporated by the condensate evaporator 2, the tar viscosity is further reduced, and the second mixture formed by mixing with water vapor has a smaller particle size, which facilitates contact with oxygen (increased specific surface area), thereby improving combustion efficiency.

[0039] Secondly, the evaporation process can separate some of the light acidic components (such as phenol) from the tar, while consuming the carbon in the tar through the water-gas reaction (C+H2O→CO+H2), reducing carbon deposit formation and extending equipment life.

[0040] Furthermore, water vapor can act as a gasifying agent in high-temperature reactions, breaking down heavy components in tar (such as asphaltenes) into small-molecule combustible gases such as CO and H2, increasing the calorific value of combustion. Simultaneously, the dilution effect of water vapor helps control the combustion temperature at around 1000℃, inhibiting NO2 production. X The generation of .

[0041] Furthermore, the evaporation of liquid water requires the absorption of 2260 kJ / kg of latent heat of vaporization. If water-containing tar is directly burned, this heat must be provided by the direct-fired tar furnace 3. After the water evaporates using the waste heat of the flue gas through the condensate evaporator 2, the water vapor participates in combustion in gaseous form, avoiding the additional energy consumption of the direct-fired tar furnace 3. At the same time, gaseous water vapor mixes more easily with tar, which can reduce the fluctuation of combustion temperature and avoid the sudden drop in furnace temperature caused by the rapid evaporation of liquid water (e.g., the evaporation of 1 kg of water can cool 1000℃ flue gas by about 200℃), thus ensuring the stability of combustion.

[0042] In one embodiment, the condensate evaporator 2 adopts a shell-and-tube heat exchanger structure, including a tube side, a shell side, and auxiliary components. The tube side is used for the flow of the first mixture and adopts a multi-pass design (such as 2-4 passes). The pipe material is 316L stainless steel (resistant to tar corrosion), the pipe diameter is Φ25×2.5mm, and the flow velocity inside the pipe is 0.5-1m / s to ensure uniform heating of the first mixture. The shell side is used for the flow of flue gas. The shell side is covered outside the tube side, and the flue gas inside the shell side can flow along the outside of the tube bundle. The shell material is Q345R carbon steel, and baffles (spaced 300-500mm) are installed inside. The baffles can guide the flue gas to laterally scour the tube bundle, enhance the turbulence effect, and improve the heat transfer coefficient.

[0043] During operation, the flue gas transfers heat to the first mixture inside the pipe through the pipe wall, causing the moisture in the mixture to evaporate into water vapor.

[0044] Continue to refer to Figure 1 The tube-side outlet of the condensate evaporator 2 is connected to the tar direct-fired furnace 3 via a heat exchanger discharge pipe, and the second mixture can be transported to the tar direct-fired furnace 3 along the heat exchanger discharge pipe. The tar direct-fired furnace 3 is equipped with a dual-fuel burner 3a and an oxygen supplement fan, and the second mixture can be mixed with oxygen in the tar direct-fired furnace 3 and completely burned at a high temperature of about 1000°C.

[0045] In one specific embodiment, the direct-fired tar furnace 3 includes an insulated furnace chamber, which consists of a refractory inner layer (made of corundum bricks, with a temperature resistance of 1790℃ and a thickness of 230mm), an insulation layer (made of lightweight high-alumina bricks, with a thickness of 114mm), and a steel outer shell, which can effectively reduce heat loss (outer wall temperature < 60℃). The furnace chamber is cylindrical, with an inner diameter of 1.2-2m and a height of 3-5m, and a slag discharge port at the bottom.

[0046] During operation, the second mixture enters the insulated furnace, where it undergoes pyrolysis and combustion reactions at a high temperature of approximately 1000℃. Inside the furnace, the high-temperature flue gas generated by combustion has a residence time of >2 seconds, ensuring the complete decomposition of harmful substances such as dioxins. The ash produced by combustion (containing minerals such as potassium and sodium) is deposited at the bottom of the furnace and is periodically discharged.

[0047] Continue to refer to Figure 1The flue gas outlet of the tar direct-fired furnace 3 is connected to the air heat exchanger 4 via a pipe. The air heat exchanger 4 is equipped with a blower. After the hot flue gas generated by combustion enters the air heat exchanger 4, it can exchange heat with the cold air once, thereby preheating the air and giving it an initial temperature so that the hot air can enter the gasifier as a gasifying agent.

[0048] In one specific embodiment, the air heat exchanger 4 is a plate-fin heat exchanger. The air heat exchanger 4 is composed of aluminum alloy or stainless steel (aluminum alloy is suitable for flue gas temperatures below 500℃, and stainless steel is suitable for flue gas temperatures between 600-800℃) fin bundles. Baffles are installed within the fin bundles to form flue gas and air channels. The fin thickness is 0.2-0.5mm, and the spacing is 2-5mm. In the plate-fin heat exchanger, the shell side corresponds to a flow channel with a larger cross-sectional area and wider fin spacing; the tube side corresponds to a flow channel with a smaller cross-sectional area and denser fin spacing.

[0049] During operation, flue gas flows through the shell side, while cold air flows through the tube side, with the two flows in counter-current or cross-current configurations. Hot flue gas (600-800℃) transfers heat to the cold air (room temperature 20℃) through fins and baffles, preheating the air to 300-450℃. Finally, the hot air flows through the tube-side outlet of air heat exchanger 4 towards the gasifier; the cooled flue gas, after one heat exchange, flows through the shell-side outlet of air heat exchanger 4 towards the shell-side inlet of condensate evaporator 2. The hot air can be used as a gasifying agent in the gasifier, and the flue gas can be used as a heat source for condensate evaporator 2.

[0050] In summary, the tar passes sequentially through tar pool 1 and condensate evaporator 2 before finally entering the tar direct-fired furnace 3 for incineration. The tar direct-fired furnace 3 produces flue gas, which passes sequentially through air heat exchanger 4 and condensate evaporator 2, achieving cascaded energy utilization through heat exchange.

[0051] It's worth noting that the reason for separating the syngas from the gasification products in biomass gasification systems is that syngas, as a high-value product (containing combustible components such as CO and H2), is often prioritized for power generation and heating. In these scenarios, direct combustion of the gasification products would contaminate the syngas with impurities such as ash and tar, reducing its calorific value and increasing pipeline resistance, thus affecting the stability and lifespan of subsequent equipment. By separating the syngas from the gasification products, ensuring its tar content is <1g / m³, it becomes beneficial for the syngas to be used independently as a clean fuel.

[0052] Secondly, for multiple gasifiers, carbonization furnaces and other tar-generating equipment, the tar is collected centrally to tar pool 1 for unified treatment, which can avoid the problems of excessive system complexity and high cost caused by decentralized treatment.

[0053] Furthermore, tar exists as a highly viscous liquid or semi-solid at room temperature. If mixed with syngas during transportation, it is prone to solidification and deposition in pipelines and valves, causing blockages. Separating syngas and tar can reduce transportation resistance. After being upgraded by the condensate evaporator 2 (temperature 100-120℃, viscosity reduced to 300-400 cP), the tar's fluidity is significantly improved, making it more suitable for centralized incineration.

[0054] Furthermore, when syngas needs to be combusted and cleaned to facilitate the emission of gasification products, the presence of tar in the syngas reduces its calorific value and affects combustion stability. Simultaneously, tar combustion requires additional energy (e.g., evaporating 1 kg of water requires 600 kJ of energy) and is prone to producing pollutants such as black smoke and polycyclic aromatic hydrocarbons due to incomplete combustion. After separation and treatment, the syngas can be stably burned as clean fuel in the dual-fuel burner 3a, while the tar is incinerated at high temperature in the tar direct-fired furnace 3, achieving the dual goals of efficient pollutant degradation and energy recovery.

[0055] The tar incineration device provided in this application mixes tar and condensate to form a first mixture with better fluidity, avoiding pipe blockage and pumping difficulties caused by the high viscosity of tar, thus ensuring the stability of system operation. The condensate evaporator 2 evaporates the water in the first mixture, forming a second mixture that is easily atomized. Combined with the high-temperature incineration process of the tar direct-fired furnace 3, this improves combustion efficiency and reduces emissions of pollutants such as black smoke and polycyclic aromatic hydrocarbons, achieving clean incineration. Simultaneously, the hot flue gas sequentially exchanges heat with the air and the first mixture twice, utilizing waste heat in a cascade manner, reducing external energy consumption and improving system energy efficiency. Furthermore, the tar incineration device provided in this application can be used in conjunction with gasifiers, carbonization furnaces, etc., enabling centralized tar treatment, reducing equipment investment and maintenance costs, and enhancing compatibility with multiple equipment scenarios.

[0056] Optionally, the tar pool 1 is equipped with a temperature control mechanism, which is used to regulate the temperature of the first mixture in the tar pool 1 so that the first mixture is maintained at 60-80°C.

[0057] At low temperatures (e.g., <50℃), tar viscosity increases and it solidifies easily, which can lead to blockages in pipelines or pumping equipment. Conversely, excessively high temperatures (>100℃) cause light components in the tar, such as benzene and toluene, to volatilize, increasing environmental and safety risks. Furthermore, temperature fluctuations may cause tar and condensate to separate, affecting subsequent processing.

[0058] Maintaining the first mixture at 60-80°C helps maintain its low viscosity (<500 cP), preserves its fluidity, and avoids volatilization and stratification issues.

[0059] In one embodiment, the temperature control mechanism employs electric heat tracing. Specifically, an electric heat tracing cable, such as a self-regulating heating cable or a mineral-insulated heating cable, is installed on the outer wall of the tar pool 1 and the outside of the pipe connecting the tar pool 1 to the condensate evaporator 2. The target temperature (e.g., 70°C) is set by a constant temperature controller, and the electric heat tracing cable can automatically adjust its heat output according to temperature changes to achieve precise temperature control within ±0.5°C.

[0060] In another embodiment, the temperature control mechanism uses steam tracing. Specifically, a spiral steam coil is arranged on the outer wall of the tar tank 1, and high-temperature steam (which can be supplied by an independent external device or replaced by flue gas at a suitable temperature) is introduced to indirectly heat the tar tank 1.

[0061] In another embodiment, the outer wall of the tar tank 1 is wrapped with insulation materials such as rock wool and polyurethane to form an insulation layer. The insulation layer has a thickness of 80-150 mm and a thermal conductivity of <0.04 W / (m·K), and is covered with an aluminum foil reflective layer and a color steel plate protective layer. The insulation layer can reduce heat exchange between the tank and the outside environment, thus reducing heat loss. The insulation layer is usually used in conjunction with electric heating or steam heating to further maintain temperature stability.

[0062] Optionally, the tar pool 1 is equipped with a density sensor to monitor the density of the first mixture, thereby inferring the ratio of tar to water therein.

[0063] For example, density sensors employ vibration density meters (such as Coriolis mass flow meters) to calculate density by detecting the vibration frequency of the mixture.

[0064] Specifically, assuming the tar volume percentage is x, then the density ρ = 1.2x + 1.0(1−x), and x can be calculated by measuring the density.

[0065] During operation, when the density sensor detects a deviation in the ratio (e.g., tar:water > 1:1), the control system can increase the condensate return flow or activate the water replenishment mechanism to add water to the tar tank 1 until the density returns to the set range.

[0066] Optionally, the tar tank 1 is equipped with a viscometer, which is used to monitor the viscosity of the first mixture to ensure that it meets the conveying requirements;

[0067] For example, a rotary viscometer is used, in which a paddle rotor is immersed in the first mixture, and the torque is measured at a speed of 20 rpm and converted into a viscosity value.

[0068] During operation, when the viscometer detects a viscosity greater than the preset value (e.g., >500 cP), the control system can adjust the temperature, add water, or remind workers to intervene, thereby ensuring that the first mixture in the system can flow smoothly.

[0069] Optionally, the tar tank 1 is equipped with a stirrer for stirring the first mixture, thereby preventing the tar from settling and caking.

[0070] For example, the agitator uses an anchor or frame-type agitator (with a diameter of 0.6-0.8 times the pool diameter) and rotates at 5-10 rpm to generate radial and axial mixed flow.

[0071] During operation, the agitator blades remain close to the bottom of the tank, and low-speed stirring prevents tar particles from settling. The stirring also improves the mixing efficiency of tar and water. Equipped with a viscometer, when the viscosity of the first mixture is detected to be higher than a preset value, stirring can further improve the fluidity of the first mixture.

[0072] Optionally, the tar incineration device provided in this application further includes a first condenser 5, which is located on the heat source discharge pipeline of the condensate evaporator 2 and is used to condense water vapor in the flue gas passing through the condensate evaporator 2 to obtain condensate, which can be returned to the tar pool 1.

[0073] For details, please refer to Figure 1 In the illustrated embodiment, the shell-side outlet of the condensate evaporator 2 is provided with a heat source discharge pipe, and a first condenser 5 is provided on the heat source discharge pipe. The hot flue gas discharged from the tar direct-fired furnace 3 passes through the air heat exchanger 4 and the condensate evaporator 2, and then enters the first condenser 5 along the heat source discharge pipe. The water vapor contained in the flue gas is condensed into liquid water, and the condensate is returned to the tar pool 1.

[0074] In one embodiment, the first condenser 5 is a shell-and-tube condenser equipped with spiral baffles. Flue gas flows through the shell side, while a cooling medium (such as cooling water or air) flows through the tube side. After two heat exchanges, the flue gas enters the first condenser 5 and exchanges heat with the cooling medium (such as circulating water, temperature 20-30°C) in the tube side, reducing the flue gas temperature to 60-80°C. The water vapor in the flue gas condenses into liquid water because its temperature is below the dew point. The condensate adheres to the surface of the tube bundle and collects in the bottom collection tank, eventually being discharged through a drain valve and flowing back to the tar pool 1 along the pipeline. In the tar pool 1, a stirrer ensures that the condensate and tar are uniformly mixed, reducing the viscosity of the first mixture and maintaining its fluidity. A density sensor monitors the density of the first mixture in real time and feeds it back to the water replenishment mechanism, dynamically adjusting the water replenishment amount to ensure a stable tar-to-water ratio.

[0075] In other embodiments, the first condenser 5 can be a heat source-dependent device such as a dryer or a waste heat boiler, thus enabling further utilization of flue gas waste heat.

[0076] Optionally, the tar incineration apparatus provided in this application further includes a second condenser 6, which is located on the heat exchange discharge pipe of the condensate evaporator 2 and is used to condense the water vapor in the second mixture discharged through the condensate evaporator 2 to obtain condensate. The condensate can be returned to the tar pool 1. By diverting the flow through the second condenser 6, the proportion of water vapor in the second mixture can also be reduced, thereby preventing water vapor from interfering with the combustion of tar.

[0077] For details, please refer to Figure 1 In the illustrated embodiment, the tube-side outlet of the condensate evaporator 2 is connected to a heat exchanger discharge pipe that leads to the tar direct-fired furnace 3. The heat exchanger discharge pipe branches into two branches. The first branch connects to the tar direct-fired furnace 3, and the second branch has a second condenser 6 and connects to the tar pool 1. After the first mixture passes through the condensate evaporator 2, the condensate is evaporated into water vapor, while the tar remains liquid. The gas-liquid two-phase flow composed of gaseous water vapor and liquid tar exhibits a significant density difference (water vapor density ≈ 0.6 kg / m³, tar droplet density ≈ 1000 kg / m³). Therefore, a certain stratification phenomenon naturally occurs in the heat exchanger discharge pipe—water vapor, due to its lower density, accumulates upwards, while tar droplets, due to their higher density, settle downwards. Utilizing this characteristic, the end of the heat exchanger discharge pipe is designed as two branches branching upwards and downwards. The upper branch is the second branch, used to supply gaseous water vapor. After the water vapor flows through the second condenser 6, it is condensed into liquid water and returned to the tar pool 1 for recycling. The lower branch is the first branch, used to transport liquid tar and entrained water vapor into the tar direct combustion furnace (3) for combustion.

[0078] The configuration and usage of the second condenser 6 are similar to those of the first condenser 5, and will not be described in detail here.

[0079] Optionally, a humidity sensor is installed on the first branch to monitor the volume percentage of water vapor in the second mixture; an electrically operated valve is installed on the second branch, which can automatically adjust the valve opening based on the signal fed back by the humidity sensor: when the water vapor content in the second mixture is greater than a preset value, the opening of the electrically operated valve is increased so that more water vapor is condensed and recovered; when the water vapor content in the second mixture is less than the preset value, the opening of the electrically operated valve is decreased to retain an appropriate amount of water vapor.

[0080] By controlling the amount of water vapor condensation, the ratio of tar to water vapor in the second mixture entering the tar direct-fired furnace 3 is maintained at a preset value. This avoids excessive water dilution of combustion efficiency while retaining an appropriate amount of water vapor to participate in the water-gas reaction and promote complete combustion.

[0081] Optionally, a high-pressure atomizing nozzle is installed on the first branch. Before entering the tar direct-fired furnace 3, the tar and water vapor flow through the high-pressure atomizing nozzle and are broken into micron-sized droplets. This increases the specific surface area of ​​the tar, making it easier to contact oxygen and improving combustion efficiency. At the same time, a high-speed turbulent boundary layer is formed on the droplet surface, which promotes the diffusion of water vapor molecules into the droplet interior. The surface tension of the tiny droplets generated by atomization is reduced, decreasing the tendency for droplet aggregation and making it easier for water vapor to encapsulate the droplets to form a stable gas-liquid dispersion system. Therefore, the tar and water vapor are mixed more uniformly. Uniform mixing causes water vapor to form a "gasifying agent shell" on the surface of the tar droplets, and the water-gas reaction occurs preferentially on the droplet surface, which can further improve combustion efficiency. The H2 and CO produced by gasification, as intermediate products, can also lower the pyrolysis activation energy of the tar, making the heavy components in the tar easier to decompose, thereby promoting complete combustion.

[0082] Optionally, the tar direct-fired furnace 3 is equipped with a swirl burner, which can enhance the turbulence of the airflow and promote the full mixing of the second mixture with oxygen.

[0083] In one embodiment, a high-pressure atomizing nozzle is used in conjunction with a swirl burner. The tangential velocity component from the swirl burner generates a centrifugal force field in the gas-liquid two-phase system, which promotes thorough mixing of the second mixture with oxygen and prolongs the residence time of the second mixture in the furnace, thus promoting secondary mixing in incompletely mixed areas. Simultaneously, in the high-temperature environment within the furnace, the expansion of water vapor inside the droplets triggers micro-explosions, breaking the tar into smaller particles and further improving combustion efficiency.

[0084] Optionally, in the tar pool 1, the ratio of tar to water is 1:1 to 1:3; after the water vapor is diverted through the second condenser 6, it enters the second mixture in the tar direct-fired furnace 3, where the ratio of tar to water vapor is 2:1 to 3:1.

[0085] It should be explained that tar is a high-viscosity liquid or semi-solid at room temperature. If left untreated, its high viscosity will result in high flow resistance in pipelines, easily clogging them and seriously affecting the normal operation of the system. By mixing tar and water in a ratio of 1:1 to 1:3 in tar tank 1, the viscosity of the tar can be reduced by the dilution effect of water, thereby improving its fluidity and facilitating pumping and pipeline transportation.

[0086] Experiments show that when the water content is >50%, the fluidity of tar is significantly improved, but at the same time, it is necessary to avoid excessive water content leading to a surge in energy consumption for subsequent evaporation and incineration.

[0087] Generally, high-viscosity tar (such as coal tar) requires a higher water content (1:2-1:3), while low-viscosity tar (such as biomass tar) can be reduced to 1:1. In industrial incineration systems, tar and condensate are often mixed at a 1:2 ratio (66% water content) to balance flowability and evaporation economy. In practical applications, the ratio can be further optimized in real time using online monitoring (such as viscometers and flow meters) to ensure system efficiency and stability.

[0088] It should also be explained that if the water vapor content in the second mixture entering the tar direct-fired furnace 3 is too high, it will have adverse effects such as incomplete combustion, producing harmful substances such as black smoke and polycyclic aromatic hydrocarbons. It will also cause flame instability, which may lead to flameout or fluctuations. In addition, excessive water vapor will absorb a large amount of heat, lower the furnace temperature, and lead to incomplete combustion of tar, generating CO and unburned carbon particles.

[0089] By setting up a second condenser 6 to divert steam, the ratio of tar to steam in the second mixture entering the tar direct-fired furnace 3 is controlled to be 2:1-3:1. An appropriate amount of steam promotes the water-gas reaction, cracking the heavy components of the tar into combustible gases and improving combustion efficiency. Simultaneously, the negative effects of excessive steam (e.g., tar:steam <1:1) are avoided, maintaining the temperature inside the direct-fired furnace at a relatively high level (1000-1200℃), effectively improving combustion efficiency and reducing pollutant emissions.

[0090] In one embodiment, the tar tank 1 is equipped with a density sensor, which can infer the ratio of tar to condensate by monitoring the density of the first mixture. The tar tank 1 is also equipped with a viscometer, which can detect whether the viscosity of the first mixture meets the conveying standards. The heat exchanger discharge pipe of the condensate evaporator 2 branches into two branches. The first branch connects to the tar direct-fired furnace 3, and the second branch is equipped with a second condenser 6 and connects to the tar tank 1. The first branch is equipped with a humidity sensor, and the second branch is equipped with an electrically operated valve. The humidity sensor and the electrically operated valve work together to regulate the ratio of tar to water vapor in the second mixture entering the tar direct-fired furnace 3.

[0091] Specifically, when the density of the first mixture deviates from the set range, it indicates a change in the ratio of tar to condensate. Simultaneously, the viscosity of the first mixture is confirmed using a viscometer, as tar viscosity decreases significantly with increasing water content; viscosity data helps determine if the ratio is appropriate. If the viscosity does not meet the conveying standards or the ratio deviates, the condensate return flow rate can be increased, or ordinary water can be added. During water replenishment, the amount of water replenished is precisely controlled through real-time feedback from the density sensor and viscometer, ensuring the fluidity of the mixture and the effectiveness of subsequent processing.

[0092] Meanwhile, a humidity sensor monitors the water vapor content in the second mixture in real time. When the water vapor content is detected to be too high, causing the ratio of tar to water vapor in the second mixture entering the tar direct-fired furnace 3 to deviate from the set range (e.g., tar: water vapor < 2:1), more water vapor can be cooled and refluxed by increasing the opening of the electric valve.

[0093] Density sensors, viscometers, humidity sensors, and electric valves work together to feed real-time monitoring data back to the control system. The control system can dynamically adjust the water replenishment and water vapor diversion operations of tar tank 1 based on this data, thereby achieving precise control of the ratio of tar to condensate and tar to water vapor in the entire system and ensuring stable system operation.

[0094] As mentioned above, the gasification system provided in this application has three main sources of condensate (third condenser 7, first condenser 5, and second condenser 6). As the gasification process continues, excessive condensate may occur in the system. Therefore, bypasses and drain valves can be installed on the condensate return pipelines related to the first condenser 5 and the second condenser 6 to discharge excess condensate as needed. Alternatively, the tar incineration device may also include a condensate recovery chamber, with the first condenser 5 and the second condenser 6 connected to it. The condensate obtained from condensation can be discharged into the condensate recovery chamber and then either discharged again or used to replenish water in the tar pool 1 as needed.

[0095] Optionally, the tar incineration apparatus provided in this application further includes a water replenishment mechanism, which is used to increase the proportion of water in the first mixture; the water replenishment mechanism includes: a water preparation tank for supplying softened ordinary water; and a heater for preheating the ordinary water so that the temperature of the ordinary water is close to the temperature of the tar in the tar pool 1.

[0096] Specifically, the backup water tank is connected to tar tank 1 via a pipe, and is equipped with a heater and control valve. The backup water tank also contains a softening resin tank or a reverse osmosis membrane device to remove calcium and magnesium ions and impurities from the water, preventing scaling; alternatively, the backup water tank may store deionized water. The heater can be a shell-and-tube heat exchanger or an electric heating rod.

[0097] Ordinary water is first softened (e.g., through ion exchange) to remove scale-forming ions such as calcium and magnesium, preventing them from reacting with acidic substances in the tar to form precipitates that could clog pipes or equipment. A heater heats the softened water to 60-80°C, matching the temperature of the tar in tar tank 1, before slowly injecting the water into tar tank 1 through pipes. During mixing, the temperature difference between the water and tar is less than 5°C, preventing the tar from solidifying due to a sudden temperature drop.

[0098] Optionally, a temperature sensor is also installed in the water tank to detect the water temperature and ensure that the temperature of the liquid used for replenishment is close to the temperature of the tar in the tar pool 1.

[0099] When the condensate in the system is insufficient, the water replenishment mechanism starts as a backup water source. The preheated temperature of the softened water used for replenishment is close to the temperature of the return condensate to avoid disrupting the system's temperature chain.

[0100] Specifically, when the density sensor in tar tank 1 detects that the ratio of tar to water deviates from the set lower limit, and / or the viscometer detects that the viscosity of the first mixture does not meet the conveying requirements, the control system starts the water replenishment mechanism. The control valve of the water replenishment mechanism opens, and the preheated softened water in the water preparation tank is replenished into tar tank 1 until the viscosity of the first mixture returns to normal.

[0101] Optionally, a heat tracing layer is provided outside the tar pool 1 and / or the pipe connecting the tar pool 1 to the condensate evaporator 2 to maintain the temperature of the first mixture.

[0102] In one embodiment, a heat tracing layer is provided on the outer wall of the tar tank 1 and on the outside of the pipe connecting the tar tank 1 to the condensate evaporator 2. The heat tracing layer is filled with insulation material, such as ceramic fiber cotton or aerogel felt. The insulation material can block the heat transfer path through its low thermal conductivity. The insulation layer is 100mm thick. A reflective layer (aluminum foil) is provided on the outside of the insulation layer. The reflective layer is 0.1mm thick and has a reflectivity greater than 95%, which can reduce radiative heat loss. The outer wall of the heat tracing layer is made of stainless steel sheet with a thickness of 1.5mm, or carbon steel with powder coating with a thickness of 2mm, which can prevent the insulation material from getting damp or mechanically damaged. The insulation layer thickness is uniformly distributed, which can avoid tar solidification caused by localized cold spots.

[0103] In another embodiment, only the pipe connecting the tar tank 1 to the condensate evaporator 2 is provided with a heat tracing layer. The heat tracing layer adopts a heating pad or an electric heat tracing structure.

[0104] For example, a heating patch is wrapped around the outer wall of the pipe and fixed with pressure-sensitive adhesive. When the heating patch is working, it converts electrical energy into heat energy to maintain the pipe temperature at all times and prevent the first mixture from condensing during pipe transportation. At this time, a heating rod is provided in the tar tank 1 to maintain the temperature of the first mixture in the tank, while the heating patch is used to maintain the temperature of the first mixture during transportation.

[0105] In another embodiment, the heat tracing layer is connected to the heat source discharge pipe of the condensate evaporator 2; the flue gas discharged from the condensate evaporator 2 enters the heat tracing layer, which can maintain the temperature of the first mixture and prevent tar from condensing at low temperature.

[0106] Specifically, the heat tracing layer wraps around the outer wall of the tar pool 1 and also covers the outside of the conveying pipe between the tar pool 1 and the condensate evaporator 2, forming a jacket structure. The heat tracing layer is connected to the heat source discharge pipe of the condensate evaporator 2. The hot flue gas discharged from the tar direct-fired furnace 3 enters the heat tracing layer after passing through the air heat exchanger 4 and the condensate evaporator 2, indirectly heating the conveying pipe between the tar pool 1 and the first mixture. At this time, the flue gas in the heat tracing layer can also serve as a heat source for heating the first mixture (thus eliminating the need for an additional temperature control mechanism).

[0107] More specifically, the pipe wall of the heat tracing layer is designed with a sandwich structure, and the sandwich is filled with insulation material to reduce heat loss.

[0108] This application also provides a biomass feedstock gasification system, including the above-mentioned tar incineration device, and a gasifier. The gasifier can convert biomass feedstock into syngas through a high-temperature thermochemical reaction, with tar and water vapor as a byproduct. The tar direct-fired furnace 3 is equipped with a dual-fuel burner 3a, which can not only burn natural gas or diesel, but also burn the syngas produced by the gasifier and a second mixture.

[0109] In one specific embodiment, the dual-fuel burner 3a adopts a multi-channel design, including: a central channel for conveying a second mixture; a middle channel for conveying syngas; an outer channel for conveying backup fuels such as natural gas and diesel; a swirling air channel surrounding the central channel, middle channel, and outer channel to provide tangential airflow and enhance the mixing effect; and an ignition system capable of simultaneously igniting multiple fuel combinations.

[0110] The dual-fuel burner 3a includes four fuel mode switching logics.

[0111] Mode 1: Backup fuel.

[0112] During startup or when the system is under low load, natural gas or diesel is fed into the dual-fuel burner 3a and ignited by an electronic igniter to maintain the furnace temperature.

[0113] Mode 2: Second mixture.

[0114] Once the tar pool 1 and the condensate evaporator 2 are running stably, the second mixture (tar to water vapor ratio of 2:1-3:1) is fed into the dual-fuel burner 3a through the central channel and burned directly at the high temperature inside the furnace without the need for additional ignition.

[0115] Mode 3: Syngas.

[0116] The syngas produced by the gasifier is fed into the dual-fuel burner 3a through the middle layer channel, where it is mixed with air for combustion. At this time, the tar direct-fired furnace 3 can also clean the syngas.

[0117] Mode 4: Syngas and second mixture.

[0118] Syngas and the second mixture are simultaneously fed into the dual-fuel burner 3a. The high reactivity of the syngas promotes tar combustion, thereby achieving synergistic efficiency of the two fuels.

[0119] A multi-source fuel complementary technology system is constructed through the dual-fuel burner 3a, which is compatible with various fuels such as natural gas, diesel, syngas, and tar to cope with different operating conditions of the gasification system. After the system is operating normally, the tar direct-fired furnace 3 can burn self-produced fuels such as syngas and tar, reducing dependence on external energy and maximizing the recovery of biomass energy.

[0120] The biomass gasification system provided in this application effectively solves the problems of difficult tar treatment, poor fuel adaptability, and high dependence on external energy in traditional biomass gasification by integrating a tar incinerator and a dual-fuel burner 3a. The system achieves harmless treatment of tar and heat recovery through a closed-loop process of tar mixing and viscosity reduction in a tar pool 1, quality improvement in a condensate evaporator 2, and high-temperature combustion in a direct-fired tar furnace 3, avoiding tar blockage of pipelines and environmental pollution. The dual-fuel burner 3a supports flexible switching between multiple fuels such as natural gas, diesel, syngas, and tar, and can meet different needs under various operating conditions, including start-up, low load, and normal operation. Simultaneously, the dual-fuel burner 3a utilizes the high reactivity of syngas to promote tar cracking and improve combustion efficiency through multi-fuel syngas co-combustion, and can further clean and treat residual impurities during syngas combustion. The system constructs a closed-loop energy chain of "biomass feedstock → syngas + tar → heat recovery", maximizing the recovery of biomass energy, reducing dependence on external fuels, and reducing overall energy consumption through the cascade utilization of waste heat, thus achieving a stable, environmentally friendly and economical biomass gasification process.

[0121] Optionally, the biomass feedstock gasification system provided in this application also includes a third condenser 7, which is located on the discharge pipeline of the gasifier and is used to cool the gasification products discharged from the gasifier, so that the tar and water vapor in the gasification products are condensed into liquid; the condensed tar and condensate enter the tar pool 1.

[0122] For details, please refer to Figure 1 In the illustrated embodiment, the gasifier outlet is provided with a gasification product discharge pipeline, and a third condenser 7 is provided on the gasification product discharge pipeline. The third condenser 7 can separate the gasification products, so that the tar and water vapor therein are condensed into liquid and flow to the tar pool 1, while the synthesis gas flows to the tar direct combustion furnace 3.

[0123] The structure and usage of the third condenser 7 are similar to those of the first condenser 5, and will not be described in detail here.

[0124] It needs to be explained that the water vapor in the gasification products mainly comes from two sources. One is the moisture contained in the biomass raw material itself, which evaporates into water vapor during the high-temperature thermochemical reaction in the gasifier (such as the dry distillation and pyrolysis process at 600-900℃). The other is the water generated by the gasification reaction, such as the combination of hydrogen and oxygen elements in the biomass to form H2O during the reaction, or the moisture brought in by the gasifying agent (such as air or water vapor) that has not fully participated in the reaction and remains there.

[0125] The water vapor in the gasification products condenses together with the tar to form a preliminary first mixture. After entering the tar pool 1, the system can adjust the ratio of tar to water to ensure the fluidity of the first mixture.

[0126] It also needs to be explained that after the gasification products enter the third condenser 7, they are cooled to below the dew point temperature (e.g., 80-150℃) by a cooling medium (such as circulating cooling water or air). The water vapor in the condenser releases latent heat due to the temperature drop and condenses from a gaseous state into liquid water. The tar (with a higher boiling point, typically >200℃) also condenses from a gaseous or aerosol state into a liquid state due to the temperature drop, forming a mixture with the liquid water. Due to the significant density difference, the mixture and the uncondensed syngas naturally separate. The mixture, with its higher density, settles to the bottom of the third condenser 7 and then flows into the tar pool 1 through a pipe; while the syngas, with its lower density, floats and is transported through another pipe to the tar direct-fired furnace 3 or other utilization units.

[0127] The third condenser 7 is usually equipped with components such as baffles and wire mesh demisters. By changing the airflow direction or increasing the gas-liquid contact area, it can enhance the droplet coalescence and gas-liquid separation effect, ensuring that the tar content in the synthesis gas is reduced to below 1g / m³, so as to meet the needs of subsequent combustion or utilization.

[0128] By using temperature control and physical separation mechanisms, the tar, water and syngas in the gasification products are separated and treated separately. This not only avoids tar from entering the combustion system with the syngas and causing blockage or pollution, but also provides the prerequisite for the centralized recovery and resource utilization of tar.

[0129] Optionally, a cyclone separator is also installed on the gasification product discharge pipeline, located upstream of the third condenser 7. The gasification products enter the cyclone separator tangentially at a speed of 15-25 m / s, generating centrifugal force, causing coarse tar and ash particles to impact the wall and fall along the cone wall.

[0130] The cyclone separator separates coarse tar particles from ash, reducing the load on the subsequent third condenser 7, preventing large amounts of coarse impurities from entering, minimizing the risk of blockage in components such as baffles and heat exchange tubes, and extending equipment maintenance cycles. It also allows for early separation, preventing the formation of a high-viscosity slurry from the high-viscosity, impurity-laden coarse tar mixed with condensate, thus reducing pumping resistance. Furthermore, alkaline metal compounds such as potassium and sodium in the ash, if introduced into the direct-fired tar furnace 3, can easily melt and adhere to the furnace or heat exchange tube surfaces at high temperatures, forming slag and affecting combustion efficiency and heat transfer. Early separation of ash reduces the amount of these substances entering the incineration system, lowering the risk of equipment corrosion and slag formation, while also improving the cleanliness of tar combustion and reducing pollutant emissions in fly ash.

[0131] Optionally, a gas-liquid separator is also installed on the gasification product discharge pipeline, located downstream of the third condenser 7. After condensation, the flow velocity of the syngas and the mixed liquid drops sharply to 0.1-0.3 m / s after entering the separator. Due to the density difference, the mixed liquid settles to the bottom and is discharged into the tar pool 1 through the liquid level control valve.

[0132] In one specific embodiment, refer to Figure 2 The gasification product discharge pipeline is sequentially equipped with a cyclone separator, a third condenser 7, and a gas-liquid separator. The cyclone separator pre-treats the gasification products, separating coarse tar particles and ash residue to prevent large amounts of impurities from entering subsequent equipment. Next, the third condenser 7 cools the gasification products after the cyclone separator treatment, condensing the tar and water vapor into liquid, achieving preliminary separation of syngas from liquid tar and water, laying the foundation for subsequent utilization of syngas and recovery of tar. Finally, the gas-liquid separator further separates the mixture from the third condenser, accurately separating syngas from tar and water based on density differences, ensuring the purity of the syngas and enabling more efficient use of it for heating, power generation, etc., ensuring a smooth entire gasification product treatment process.

[0133] Optionally, the gasification product discharge pipeline is equipped with an insulation or heat tracing system (see the heat tracing layer mentioned above) to control the temperature inside the pipeline to be greater than 150°C and prevent residual tar from condensing and clogging it.

[0134] Optionally, the inner wall of the gasification product discharge pipeline is provided with an oleophobic coating (such as a nano-ceramic composite with a coating thickness of 50-100μm) to reduce tar adhesion.

[0135] In one specific embodiment, the condensation temperature of the third condenser 7 is 80-150°C to separate the synthesis gas from the gasification products and to condense the tar and water vapor into a liquid state; the temperature of the first mixture in the tar pool 1 is maintained at 60-80°C to prevent the tar from solidifying and to ensure the fluidity of the first mixture; the operating temperature of the condensate evaporator 2 is 100-120°C to ensure that the water in the first mixture is completely evaporated and that some of the light components in the tar are vaporized, while the heavy components remain liquid; the combustion temperature of the tar direct-fired furnace 3 is 1000-1200°C; the temperature of the hot flue gas discharged from the tar direct-fired furnace 3 is 600-800°C, the hot flue gas enters the air heat exchanger 4, and after one heat exchange, it is cooled to 400-500°C, the air is preheated to 300-450°C, and the cooled flue gas enters the condensate evaporator 2, and after a second heat exchange, it is cooled to 80-150°C.

[0136] Typical components of tar include benzene (boiling point 80℃), toluene (boiling point 110℃), naphthalene (boiling point 218℃), and polycyclic aromatic hydrocarbons (boiling point > 250℃). Utilizing the boiling point difference between tar and syngas (mainly composed of CO and H2, boiling point -191 to 252℃), the gasification products are cooled to 80-150℃ via a third condenser 7. Without affecting the gaseous state of the syngas, only a small amount of light components in the tar (such as benzene and toluene) may remain in a gaseous state, while most components are condensed into a liquid state, facilitating tar separation and collection. During this process, water vapor in the gasification products is liquefied along with the tar, forming a preliminary first mixture for subsequent processing.

[0137] Maintaining the temperature of the first mixture in tar tank 1 at 60-80℃ can reduce the viscosity of the tar and meet the pumping requirements of the centrifugal pump.

[0138] The condenser evaporator 2 evaporates the water in the first mixture, thus upgrading the tar. At 100-120℃ (slightly above the boiling point of water), the water is completely evaporated, and the light components in the tar, such as benzene and toluene (boiling point <120℃), vaporize with the water vapor, while the heavy components, such as naphthalene and polycyclic aromatic hydrocarbons, remain liquid, forming a second mixture containing light tar vapor, heavy tar droplets, and water vapor. This mixture reduces tar viscosity, improves atomization, and allows for more complete combustion, thereby reducing CO emissions and increasing combustion efficiency. The upgraded second mixture has stable flowability, allowing for long-distance transport and enhancing the system's flexibility and reliability.

[0139] Reference Figure 3The tar direct-fired furnace 3 operates at a temperature greater than 1000℃ to achieve complete combustion of tar. The tar direct-fired furnace 3 discharges high-temperature flue gas at 600-800℃, which enters the air heat exchanger 4 to preheat the air used as a gasifying agent, raising the air to 300-450℃, which meets the temperature requirements of the gasifying agent. After one heat exchange, the high-temperature flue gas is cooled to 400-500℃.

[0140] Continue to refer to Figure 3 The medium-temperature flue gas discharged from the air heat exchanger 4 at 400-500℃ enters the condensate evaporator 2, so that the heat exchange temperature of the condensate evaporator 2 reaches 100-120℃, so as to evaporate the water in the first mixture; the medium-temperature flue gas is cooled to 80-150℃ after secondary heat exchange.

[0141] The low-temperature flue gas of 80-150℃ discharged from the condensate evaporator 2 can be directly discharged through the chimney, or it can be fed into the dryer or waste heat boiler for reuse of waste heat.

[0142] After the flue gas passes through the condensate evaporator 2 and is cooled to 80-150℃ through secondary heat exchange, the low-temperature flue gas just meets the heat tracing requirements of the tar pool 1. At this time, the low-temperature flue gas can also be introduced into the heat tracing layer to use the residual heat of the flue gas to maintain the temperature in the tar pool 1 at 60-80℃, ensuring that the tar remains in a liquid state.

[0143] By utilizing waste heat in a gradient manner, the originally emitted low-temperature flue gas is converted into a heat source for tar pool 1, which not only avoids additional energy consumption (such as adding a temperature control mechanism) but also prevents tar from solidifying and clogging pipes, thus maximizing the system's energy efficiency.

[0144] Optionally, the low-temperature flue gas enters the heat tracing layer to heat or maintain the temperature of the first mixture. After three heat exchanges, the low-temperature flue gas is further cooled, becoming cold flue gas. The cold flue gas can be returned to the tar direct-fired furnace 3 to regulate the combustion temperature, or to regulate the temperature of the high-temperature flue gas discharged from the tar direct-fired furnace 3. The cold flue gas that does not participate in the return flow is discharged through the chimney.

[0145] By dynamically mixing cold flue gas and high-temperature flue gas, precise control of hot flue gas temperature is achieved, which can avoid thermal stress damage to subsequent equipment such as air heat exchanger 4 due to excessive temperature, and ensure stable system operation and waste heat recovery efficiency.

[0146] If necessary, the cold flue gas can also be mixed into the air heat exchanger 4 to regulate the temperature of the medium-temperature flue gas, so as to meet the usage requirements of the condensate evaporator 2.

[0147] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A tar incineration apparatus characterized by comprising: The tar pool (1) is used for storing tar, and the tar can be mixed with condensed water in the tar pool (1) to form a first mixture which is convenient to flow in the pipeline; the condensed water evaporator (2) is communicated with the tar pool (1), and the condensed water in the first mixture is evaporated into water vapor after the first mixture enters the condensed water evaporator (2), and the water vapor forms a second mixture with the tar; the tar direct combustion furnace (3) is communicated with the condensed water evaporator (2), and the second mixture is burned after entering the tar direct combustion furnace (3) to generate hot flue gas; the air heat exchanger (4) is communicated with the tar direct combustion furnace (3), and the hot flue gas enters the air heat exchanger (4) as a heat source of the air heat exchanger (4), and the hot flue gas can preheat air, and the obtained hot air can be used as a gasification agent of a gasification furnace; the flue gas after completing the heat exchange in the air heat exchanger (4) flows to the condensed water evaporator (2) as a heat source of the condensed water evaporator (2); the tar burning device further comprises a first condenser (5) and a second condenser (6); the first condenser (5) is arranged on a heat source discharge pipeline of the condensed water evaporator (2), and is used for condensing water vapor in flue gas passing through the condensed water evaporator (2) to obtain condensed water, and the condensed water can flow back to the tar pool (1); the second condenser (6) is arranged on a heat exchange object discharge pipeline of the condensed water evaporator (2), and is used for condensing water vapor in the second mixture discharged through the condensed water evaporator (2) to obtain condensed water, and the condensed water can flow back to the tar pool (1); by means of the second condenser (6), the proportion of water vapor in the second mixture can be reduced, so that the water vapor can avoid interfering with the burning of the tar. The tar pool (1) is configured with: a temperature control mechanism for adjusting the temperature of the first mixture in the tar pool (1) so that the first mixture is maintained at 60-80 DEG C; and / or a density sensor for monitoring the density of the first mixture so as to deduce the proportion of tar and water therein; and / or a viscometer for monitoring the viscosity of the first mixture to ensure that it meets the delivery requirements; and / or a stirrer for stirring the first mixture to prevent the tar from being deposited and hardened. The proportion of tar and water in the tar pool (1) is 1:1-1:3; after the water vapor is shunted by the second condenser (6), the proportion of tar and water vapor in the second mixture entering the tar direct combustion furnace (3) is 2:1-3:

1. Further comprising a water supplementing mechanism, the water supplementing mechanism is used for increasing the proportion of water in the first mixture; the water supplementing mechanism comprises: a water storage bin for supplying ordinary water which has been subjected to softening treatment; a heater for preheating the ordinary water so that the temperature of the ordinary water approaches the temperature of the tar in the tar pool (1). The heat exchange object discharge pipeline branches into two branches, a first branch is communicated with the tar direct combustion furnace (3), and a second branch is provided with the second condenser (6) and is communicated with the tar pool (1). ​ ​ ​ ​ ​ 2. The tar incineration device according to claim 1, characterized in that ​ ​ ​ ​ ​ 3. The tar incineration device according to claim 1, characterized in that ​ ​ 4. The tar incineration device according to claim 1, characterized in that, ​ ​ ​ ​ 5. The tar incineration device according to claim 1, characterized in that, ​ The first branch is provided with a humidity sensor, which is used to monitor the water vapor volume ratio in the second mixture; The second branch is provided with an electric opening degree valve, which can automatically adjust the valve opening degree according to the signal feedback of the humidity sensor; When the water vapor content in the second mixture is greater than the preset value, the opening degree of the electric opening degree valve is increased, so that more water vapor is condensed and recovered; When the water vapor content in the second mixture is less than the preset value, the opening degree of the electric opening degree valve is reduced to retain an appropriate amount of water vapor.

6. The tar incineration device according to claim 1, characterized in that A bypass and a drain valve are arranged on the condensate return pipeline related to the first condenser (5) and the second condenser (6) to discharge excess condensate as needed; Alternatively, the tar incineration device further comprises a condensate recovery bin, the first condenser (5) and the second condenser (6) are connected with the condensate recovery bin, and the condensed condensate can be discharged into the condensate recovery bin and then discharged or supplemented to the tar pool (1) as needed.

7. The tar incineration device according to any one of claims 1 to 6, characterized in that A heating layer is arranged outside the pipeline connecting the tar pool (1) and / or the condensate evaporator (2); The heating layer is connected with the heat source discharge pipeline of the condensate evaporator (2); The flue gas discharged from the condensate evaporator (2) enters the heating layer, which can maintain the temperature of the first mixture.

8. A biomass feedstock gasification system, characterized by, The tar incineration device according to any one of claims 1-7 further comprises a gasification furnace, which can convert biomass raw materials into synthesis gas through high-temperature thermochemical reaction, and generate tar and water vapor as by-products; The tar direct combustion furnace (3) is provided with a dual-fuel burner (3a), which can not only burn natural gas or diesel oil, but also burn synthesis gas generated by the gasification furnace and the second mixture.

9. The biomass feedstock gasification system of claim 8, wherein, A third condenser (7) is further included, which is arranged on the discharge pipeline of the gasification furnace and used to cool the gasification products discharged from the gasification furnace, so that the tar and water vapor in the gasification products are condensed into liquid state; The condensed tar and condensate enter the tar pool (1).

10. The biomass feedstock gasification system of claim 9, wherein, The condensation temperature of the third condenser (7) is 80-150℃, so as to separate the synthesis gas in the gasification products and condense the tar and water vapor into liquid state; The temperature of the first mixture in the tar pool (1) is maintained at 60-80℃, so as to prevent tar solidification and ensure the fluidity of the first mixture; The working temperature of the condensate evaporator (2) is 100-120℃, so as to facilitate the complete evaporation of water in the first mixture and gasification of part of the light components in the tar, while the heavy components remain in liquid state; The combustion temperature of the tar direct combustion furnace (3) is 1000-1200℃. The temperature of the hot flue gas discharged by the tar direct combustion furnace (3) is 600-800 ℃, the hot flue gas enters the air heat exchanger (4), is cooled to 400-500 ℃ after one heat exchange, and the air is preheated to 300-450 ℃, the cooled flue gas enters the condensate evaporator (2), and is cooled to 80-150 ℃ after two heat exchanges.

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