Multi-channel sampling trapping and grading tar removal synergistic method for biomass gasification poly-generation device

Abstract

The invention discloses a multi-channel sampling trapping and grading tar removal synergistic method for a biomass gasification poly-generation device, and relates to the technical field of biomass gas sampling analysis and purification control, and the method comprises the following steps: establishing a heating sampling pipeline with temperature control, a multi-channel sampling manifold, a constant distribution analysis channel, a trapping channel and a safety channel flow; the main gas path is sequentially subjected to high-temperature filtration and multi-stage condensation, and condensate is collected in different bins; the sampling channel is used for trapping tar through parallel adsorption tubes / sampling bottles and is periodically switched by adopting a multi-way valve; synchronously feeding the sample gas into a micro GC to obtain components such as H / CO / CH / CO, calibrating a sensor on line by using standard gas, and constructing soft measurement results of a calorific value and a tar index; when the tar index, the pressure difference or the CO leakage reaches a threshold value, the gas supply ratio of the condensing medium, the bypass catalytic cracking bed and the reactor is adjusted in a linkage manner, and inerting release and isolation are triggered. According to the method, sampling representativeness and tar removal are integrated and coordinated, the risk of dew formation and blockage is reduced, and the safe and stable operation capacity of a distributed system is improved.

Description

Technical Field

[0001] This invention relates to the field of biomass gas sampling, analysis, purification, and operational safety control technology, specifically providing a multi-channel sampling and collection method and graded tar removal synergistic method for biomass gasification combined production units. Background Technology

[0002] Biomass gasification has significant resource utilization value in heating, drying, and distributed energy scenarios. However, the gasified fuel typically contains dust, water vapor, and tar. Tar condensation at the cold end can clog sampling pipelines and purification equipment, leading to inaccurate monitoring, equipment downtime, and safety risks. Meanwhile, accurate online analysis of fuel composition / calorific value often relies on expensive analytical instruments, which are difficult and costly to maintain in rural areas.

[0003] Existing technologies typically design "sampling analysis" and "tar removal and purification" as two separate systems: the sampling system is prone to failure due to condensation; the purification system lacks a dynamic adjustment strategy based on the actual tar level, making it difficult to balance purification effectiveness and energy consumption. Therefore, there is an urgent need for a method that can coordinate multi-channel representative sampling, tar classification and collection, and online calibration control to achieve long-term stable and safe operation. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a multi-channel sampling and collection method for graded tar removal in a biomass gasification polygeneration device. Through a process of "heated sampling - constant flow distribution - parallel collection - graded condensation - online calibration - linkage control - safety interlock", the representativeness of sampling and purification control form a closed loop.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-channel sampling and trapping method for staged tar removal in a biomass gasification polygeneration unit, comprising: establishing a heated sampling pipeline and a multi-channel sampling manifold connected to the gasification outlet, and constantly distributing the flow rate of each channel; performing staged condensation on the main gas path through a condensation and tar removal control unit and collecting the condensate in separate compartments; performing parallel adsorption and trapping of tar and light hydrocarbons in the sampling channel through a multi-channel sampling / trapping unit, and sending the sample gas from another channel into a micro gas chromatograph for component analysis; periodically calibrating the online sensor based on the micro gas chromatograph analysis results to obtain soft measurement results of calorific value and tar index; when the tar index or pressure difference exceeds the threshold, adjusting the flow rate of the condensing medium, the temperature of the bypass catalytic cracking bed, and the ratio of the reactor gasifying agent in linkage, and cutting off the sampling and main gas path to achieve inerting and venting when triggering safety thresholds such as backfire or CO leakage.

[0006] In a preferred embodiment, the heated sampling pipeline uses a heating cable and a temperature sensor to control the pipeline temperature at 20-40°C above the sample gas dew point, and a high-temperature resistant filter is installed at the sampling inlet to reduce particulate matter contamination of downstream valves and analyzers.

[0007] In a preferred embodiment, the constant distribution is achieved by using a critical orifice plate or a mass flow controller in conjunction with manifold pressure feedback, and the flow ratio of the analysis channel, the collection channel and the safety channel is controlled to be (0.2~0.5):(0.3~0.6):(0.1~0.3).

[0008] In a preferred embodiment, the parallel adsorption and trapping is periodically switched between the A / B trapping branches via a multi-port valve, so that online trapping and desorption regeneration alternate, and timestamps are recorded to form a tar trapping dataset.

[0009] In a preferred embodiment, the staged condensation is provided with at least three condensation sections, with condensation temperature windows of T1=120~220℃, T2=30~90℃, and T3=-5~15℃, and the temperature of each condensation section or the flow rate of the cooling medium is dynamically adjusted according to the tar index.

[0010] In a preferred embodiment, the periodic calibration involves injecting a standard mixed gas or zero gas every 1 to 6 hours, and updating the online sensor calibration coefficients using a weighted least squares method based on the results of micro gas chromatography analysis, thereby reducing errors caused by drift and cross-interference.

[0011] The technical solution provided by this invention has the following beneficial effects: (1) The sampling and tar removal purification are designed in a coordinated manner, and the representativeness is improved by using heated sampling and constant flow distribution, and the condensation and blockage are reduced; (2) By using parallel trapping and multi-way valve switching, sampling can be carried out without interruption and a tar trapping dataset can be formed, which is convenient for diagnosis and maintenance; (3) Utilize micro GC and standard gas for online calibration to construct a soft measurement system for calorific value and tar index, thereby reducing the cost of online monitoring; (4) Based on the linkage adjustment of condensation and cracking based on tar index / pressure difference threshold, a balance between purification effect and energy consumption is achieved; (5) Rapid isolation and inerting are achieved through safety interlocks such as backfire and CO leakage, thereby improving system safety. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a multi-channel sampling and collection method for graded tar removal in a biomass gasification polygeneration unit according to the present invention. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention. Example

[0015] like Figure 1 As shown in the figure, the multi-channel sampling and collection and graded tar removal synergistic method for a biomass gasification polygeneration unit provided in this embodiment includes the following steps: S1: Establishment and constant flow distribution of the heating sampling pipeline.

[0016] Connect the sampling probe to the vaporization outlet and install a high-temperature resistant filter at the sampling inlet; use a heating tape and temperature sensor to control the temperature of the sampling pipeline at 20-40°C above the dew point; achieve multi-channel constant flow distribution through a critical orifice plate or mass flow controller, so that the flow ratio of the analysis channel, the collection channel and the safety channel is controlled at (0.2-0.5):(0.3-0.6):(0.1-0.3).

[0017] S2: Main gas path staged condensation and condensate collection in separate compartments.

[0018] The main gas path passes through a high-temperature filtration section and at least three condensation sections in sequence, with condensation temperature windows of T1=120~220℃, T2=30~90℃, and T3=-5~15℃, respectively. The condensate at each stage is collected independently and the mass flow rate is recorded as the basis for subsequent tar index calculation and condensation parameter optimization.

[0019] S3: Parallel adsorption and trapping and multi-way valve cycle switching.

[0020] At least two adsorption tube groups are set up in the collection channel as A / B collection branches. The multi-port valve switches them at a preset cycle of t=5 to 30 minutes, so that one branch collects online while the other branch desorbs, regenerates or replaces. The switching time is timestamped to form a tar collection dataset containing temperature, flow rate and collection amount.

[0021] S4: Micro GC online analysis, periodic calibration and soft measurement.

[0022] The sample gas from the analysis channel was fed into a micro gas chromatograph to obtain H2 / CO / CH4 / CO2 and light hydrocarbon components. A standard mixed gas or zero gas was injected into the manifold every 1–6 hours. The online sensor calibration coefficients were updated using a weighted least squares method based on the micro GC results. The tar index TI was calculated based on the condensate mass flow rate m_cond, the adsorption tube weight gain m_ads, and the filtration pressure difference ΔP_filter. The calorific value and safety margin were then estimated in conjunction with the component analysis.

[0023] S5: Interlocking control and safety interlock.

[0024] When TI exceeds the threshold TI_H or the pressure difference is abnormal, at least one control action will be executed in conjunction with the action: increase the reactor bed temperature by 10–50°C or decrease the feed rate by 5–20%; increase the flow rate of the cooling medium in the primary condenser section by 10–40%; open the catalytic cracking bypass and control the cracking bed temperature at 650–850°C. When the pressure difference ΔP_samp in the sampling pipeline is detected to be ≥3 kPa, the pressure difference ΔP_main in the main gas path is detected to be ≥5 kPa, the CO leakage concentration in the gas pipeline is ≥50 ppm, the outlet oxygen content is ≥2.0%, or a backfire signal is detected, the safety interlock will be triggered: the sampling valve will be closed and the sampling pipeline and the main gas path will be inerted and purged, while the gas will be switched to the safety burner or flare.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention; any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-channel sampling and collection method for combined staged tar removal in a biomass gasification polygeneration unit, characterized in that, include: Establish a heated sampling pipeline and a multi-channel sampling manifold connected to the gasification outlet, and distribute the flow rate of each channel at a constant level; The main gas path is subjected to staged condensation through condensation and impurity removal and tar control unit, and the condensate is collected in separate compartments. The tar and light hydrocarbons are adsorbed and captured in parallel in the sampling channel by a multi-channel sampling / collection unit, and the sample gas in another channel is sent to a micro gas chromatograph for component analysis. The online sensor was periodically calibrated based on the results of micro gas chromatography analysis to obtain soft measurement results of calorific value and tar index. When the tar index or pressure difference exceeds the threshold, the flow rate of the condensing medium, the temperature of the bypass catalytic cracking bed, and the ratio of the gasifying agent in the reactor are adjusted in a coordinated manner. When safety thresholds such as backfire or CO leakage are triggered, the sampling and main gas path are cut off to achieve inerting and release.

2. The method according to claim 1, characterized in that, The heated sampling pipeline uses a heating cable and a temperature sensor to control the pipeline temperature at 20-40°C above the sample gas dew point, and a high-temperature resistant filter is installed at the sampling inlet to reduce the content of particulate matter with a particle size >5μm to a preset threshold.

3. The method according to claim 1, characterized in that, The constant distribution includes: setting a critical orifice plate or mass flow controller in each channel, and controlling the flow ratio of the analysis channel, the collection channel and the safety channel to (0.2~0.5):(0.3~0.6):(0.1~0.3) in combination with manifold pressure feedback, and maintaining the total sampling flow rate at 1~5 L / min.

4. The method according to claim 1, characterized in that, The parallel adsorption and capture includes: setting at least two adsorption tube groups as A / B capture branches, switching them at a preset period of t=5 to 30 minutes through a multi-port valve, so that while one branch captures online, the other branch is desorbed, regenerated or replaced, and the switching time is timestamped to form a tar capture dataset.

5. The method according to claim 1, characterized in that, The staged condensation includes at least three condensation sections with condensation temperature windows of T1=120~220℃, T2=30~90℃, and T3=-5~15℃, respectively. T1, T2, and T3 are dynamically corrected based on the gas flow rate and the tar index obtained by soft measurement to ensure that the residual tar at the outlet of the condensation section is lower than a preset threshold.

6. The method according to claim 1, characterized in that, The periodic calibration includes: injecting a standard mixed gas or zero gas into the sampling manifold every 1 to 6 hours, using the components obtained by micro gas chromatography as a reference, and updating the zero point, range, and cross-interference coefficient of the online sensor using the weighted least squares method.

7. The method according to claim 1 or 5, characterized in that, The tar index is calculated by comprehensively considering the condensate mass flow rate, adsorption tube weight gain, and sample gas temperature-pressure-flow parameters. The calculation formula is: TI = w1·m_cond + w2·m_ads + w3·ΔP_filter, where w1, w2, and w3 are preset weights.

8. The method according to claim 7, characterized in that, When TI exceeds the threshold TI_H, at least one of the following controls is executed: Increase the bed temperature of the reaction unit by 10–50°C or reduce the feed rate by 5–20% to prolong the residence time; Increase the flow rate of the cooling medium in the primary condensation section by 10-40%; Open the catalytic cracking bypass and control the cracking bed temperature at 650–850℃.

9. The method according to claim 1, characterized in that, The safety thresholds include at least the following: sampling pipeline pressure difference ΔP_samp ≥ 3 kPa, main gas line pressure difference ΔP_main ≥ 5 kPa, CO leakage concentration in the gas pipeline ≥ 50 ppm, outlet oxygen content ≥ 2.0%, or detection of a backfire signal; when any safety threshold is met, the sampling valve is closed and the sampling pipeline and main gas line are purged with inerting gas, and the gas is switched to a safety burner or flare.

10. The method according to claim 1, characterized in that, The method also includes batch-wise association of micro gas chromatography, sensor, differential pressure and condensate fractionation yield data to generate a traceable operation data package for equipment maintenance and carbon accounting.

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