Biomass gas heat metering system

Abstract

The utility model discloses a biomass gas heat metering system, include: main gas pipeline, branch gas pipeline, purification subassembly, calorific value analyzer and controller, be provided with main flowmeter on main gas pipeline, branch gas pipeline with main gas pipeline intercommunication, be provided with the flowmeter before purification and the flowmeter after purification on branch gas pipeline, and the flowmeter before purification and the flowmeter after purification are placed respectively in the gas inlet end and the gas outlet end of branch gas pipeline, purification subassembly is located on branch gas pipeline between the flowmeter before purification and the flowmeter after purification, and purification subassembly is used for purifying the gas in branch gas pipeline, and calorific value analyzer is located in the gas outlet end of branch gas pipeline, and main flowmeter, the flowmeter before purification, the flowmeter after purification, calorific value analyzer all are connected with controller. The heat metering system in the utility model can improve the accuracy and reliability of heat metering.

Description

Technical Field

[0001] This utility model relates to the field of energy metering technology, and more specifically to a biomass gas heat metering system. Background Technology

[0002] With the widespread application of renewable energy, biomass gas, as a clean and low-carbon fuel, has received increasing attention in industrial kilns, power generation equipment, and other fields. The accuracy of its heat measurement is crucial for energy efficiency assessment, cost accounting, and emission control. However, existing biomass gas heat measurement methods have some problems and urgently need improvement.

[0003] Currently, the mainstream method for metering the heat of biomass gas generally adopts the calculation model of "flow rate × calorific value". In practical applications, biomass gas inevitably carries a large amount of impurities such as water vapor, tar, and dust during its generation process. Specifically, biomass gas has the following characteristics: water vapor content in the gas reaches 15%-35% (volume ratio), and tar droplet concentration is 50-1500 mg / Nm³. 3 The particulate matter content is 300-1500 mg / Nm³. 3 The presence of these impurities introduces inherent flaws into the measurement process.

[0004] On the one hand, sensors used for flow measurement (such as vortex flow meters and ultrasonic flow meters) directly measure the total volumetric flow rate of wet gas containing impurities, where the volume occupied by water vapor, tar, and dust particles is not separated. On the other hand, calorific value analysis equipment (such as gas chromatographs and infrared spectrometers) must first purify the gas to avoid contamination or damage from impurities. This involves removing dust, tar, and moisture through processes such as filtration, condensation, and drying, and only testing the calorific value of the clean, dry gas. This inconsistency between the test samples of "impurity-containing flow rate" and "clean calorific value" means that their product cannot accurately reflect the actual effective heat of biomass gas. For example, when the volumetric moisture content of the gas reaches 20%, the calorific value calculated using traditional methods will be about 20% higher than the actual value, seriously affecting the reliability of the measurement results.

[0005] Therefore, developing a biomass gas heat metering system that can accurately separate impurity volume and unify flow rate and calorific value detection conditions is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] In view of this, the present invention provides a biomass gas heat metering system that can accurately separate the volume of impurities and achieve unified flow and calorific value detection conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A biomass gas heat metering system, comprising:

[0009] The main gas pipeline is equipped with a main flow meter.

[0010] The gas distribution pipeline is connected to the main gas pipeline; the gas distribution pipeline is equipped with a pre-purification flow meter and a post-purification flow meter, which are respectively located at the inlet and outlet of the gas distribution pipeline.

[0011] A purification component is located on the gas distribution pipeline between the pre-purification flow meter and the post-purification flow meter; the purification component is used to purify the gas in the gas distribution pipeline.

[0012] A calorific value analyzer, wherein the calorific value analyzer is located at the outlet end of the gas distribution pipeline;

[0013] The controller is connected to the main flow meter, the pre-purification flow meter, the post-purification flow meter, and the calorific value analyzer.

[0014] The beneficial effect of adopting the above technical solution is that by setting up flow meters before and after purification, the volumetric flow difference between the impure gas and the clean gas can be directly measured, thereby accurately calculating the volume ratio of impurities and avoiding the measurement error caused by not considering the influence of impurities in traditional methods.

[0015] Preferably, the purification assembly includes a filter, a cooler, a dust collector, a tar remover, and a water remover arranged sequentially along the gas flow direction. The sequentially arranged filter, cooler, dust collector, tar remover, and water remover effectively remove various impurities such as dust, tar, and water vapor from the gas, ensuring that the gas entering the calorific value analyzer is clean and dry, thus improving the accuracy of calorific value measurement.

[0016] Preferably, the cooling pipe of the cooler is sleeved outside the gas distribution pipeline, and an inlet and an outlet are respectively provided at both ends of the cooling pipe. Efficient cooling of the gas is achieved by circulating cooling water within the cooling pipe, which can quickly reduce the gas temperature from 80-100℃ to below 40℃.

[0017] Preferably, the portion of the gas distribution pipe located between the main gas pipe and the filter screen is inclined. This inclined design allows impurities such as moisture, dust, and tar, which have undergone preliminary purification by the cooler and filter screen, to flow smoothly back to the main gas pipe, preventing the accumulation of impurities in the gas distribution pipe and reducing the risk of pipe blockage.

[0018] Preferably, the range ratio of the pre-purification flow meter to the post-purification flow meter is ≥1.5:1.

[0019] Preferably, the diameter of the gas distribution pipeline is 1 / 10 to 1 / 5 of the diameter of the main gas pipeline, the connection point of the gas distribution pipeline and the main gas pipeline is located downstream of the main flow meter, and the distance between the connection point and the main flow meter is 1 to 2 times the diameter of the gas distribution pipeline.

[0020] As can be seen from the above technical solution, compared with the prior art, this utility model discloses a biomass gas heat metering system, the beneficial effects of which are:

[0021] (1) By directly measuring the volume difference between impurity-containing and clean gas through dual flow meters, the indirect measurement error of the traditional humidity compensation method is avoided. Tests show that the measurement error can be controlled within ±1.5% in the range of 10%-30% of impurity volume, which is better than the ±2.5% required by the national standard.

[0022] (2) The purification components adopt multi-stage processing units, which can be flexibly adjusted according to the specific composition of biomass gas (such as tar content and dust particle size distribution). It can also be applied to gas metering from different sources such as straw gasification and landfill gas. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 The attached figure is a schematic diagram of the heat metering system provided by this utility model;

[0025] Figure 2 The attached figure is a structural schematic diagram of the connection between the cooler and the gas distribution pipeline provided by this utility model.

[0026] In the figure,

[0027] 1-Main gas pipeline; 2-Main flow meter; 3-Branch gas pipeline; 4-Flow meter before purification; 5-Flow meter after purification; 6-Calorific value analyzer; 7-Controller; 8-Filter screen;

[0028] 9-Cooler;

[0029] 91-Cooling pipe; 92-Water inlet; 93-Water outlet;

[0030] 10-Dust collector; 11-Tar remover; 12-Water remover. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] Example 1:

[0033] This utility model discloses a biomass gas heat metering system, including:

[0034] Main gas pipeline 1, with a main flow meter 2 installed on the main gas pipeline 1;

[0035] The gas distribution pipeline 3 is connected to the main gas pipeline 1. The gas distribution pipeline 3 is equipped with a pre-purification flow meter 4 and a post-purification flow meter 5, which are respectively located at the inlet and outlet of the gas distribution pipeline 3.

[0036] The purification component is located on the gas distribution pipeline 3 between the pre-purification flow meter 4 and the post-purification flow meter 5; the purification component is used to purify the gas in the gas distribution pipeline 3.

[0037] Calorific value analyzer 6 is located at the gas outlet end of the gas distribution pipeline 3;

[0038] The controller 7, main flow meter 2, pre-purification flow meter 4, post-purification flow meter 5, and calorific value analyzer 6 are all connected to the controller 7.

[0039] To further optimize the above technical solution, the main flow meter 2 can be an ultrasonic flow meter, a V-cone flow meter, a bend flow meter, etc., and is used to measure the total volumetric flow rate Q1 of the impurity-containing gas flowing through the main gas pipeline 1 in real time. The main flow meter 2 has a wide range ratio and anti-dust adhesion function, and can be used when the impurity (dust + tar) content is ≤50g / Nm³. 3 To work stably in an environment.

[0040] To further optimize the above technical solution, the model of the pre-purification flow meter 4 is the same as that of the main flow meter 2. Ultrasonic flow meters, V-cone flow meters, and bent-tube flow meters can be selected to measure the volumetric flow rate q1 of the untreated sampled gas containing impurities. The pre-purification flow meter 4 is made of stainless steel to enhance its wear resistance and corrosion resistance.

[0041] To further optimize the above technical solution, the purified flow meter 5 can be an orifice plate flow meter, ultrasonic flow meter, etc. This flow meter has a wide range of choices. Because it measures clean gas, there is no need to consider the influence of impurities. It is used to measure the volumetric flow rate q2 of clean sample gas after being treated by the purification component. The accuracy class of this flow meter is ≥0.5 and it is suitable for clean gas metering.

[0042] To further optimize the above technical solution, the calorific value analyzer 6 can be equipped with a chromatographic analyzer, a spectrometer, an infrared analyzer, etc. The calorific value analyzer 6 is used to measure the calorific value H (unit: kJ / Nm³) of clean fuel gas. 3 The calorific value analyzer 6 has a built-in automatic calibration function, which calibrates the instrument with a standard gas sample every 2 hours.

[0043] To further optimize the above technical solution, controller 7 adopts an industrial-grade PLC (generally a PLC that can be directly connected to the gasification system), with a built-in data processing program, which receives Q1, q1, q2, and H signals in real time, and calculates the actual effective heat of biomass gas according to the following steps:

[0044] Calculate the volume percentage of impurities (water, tar, dust) in the sampled gas: η=(q1-q2) / q1×100% Correct the effective gas volume flow rate of main gas pipeline 1: Q=Q1×(1-η)

[0045] Calculate the actual effective heat: E = Q × H.

[0046] To further optimize the above technical solution, the purification component includes a filter screen 8, a cooler 9, a dust collector 10, a tar remover 11, and a water remover 12 arranged sequentially along the gas flow direction.

[0047] To further optimize the above technical solution, the filter screen 8 has a precision of 50μm and can intercept dust particles with a diameter ≥50μm. The filter screen 8 is made of stainless steel sintered mesh and can be cleaned by backflushing online.

[0048] To further optimize the above technical solution, the cooler 9 adopts a water-cooled jacket design. The temperature of the biomass gas drops from 80-100℃ to below 40℃ after passing through the cooler, causing the water vapor in the biomass gas to condense into liquid. The tar and dust mix with the large water droplets and fall back into the main gas pipeline 1 under the action of gravity.

[0049] To further optimize the above technical solution, the dust collector 10 can be a small bag filter to remove the fine dust (particle size ≥1μm) remaining after cooling, with a dust removal efficiency ≥99%.

[0050] To further optimize the above technical solution, the tar remover 11 can be a packed tower absorption device, which adopts oil washing circulation spray to absorb the residual tar droplets in the gas, with a tar removal rate of ≥95%.

[0051] To further optimize the above technical solution, the water remover 12 can be a molecular sieve dryer, which removes water vapor from the fuel gas through an adsorbent, so that the outlet gas dew point is ≤4℃, which meets the gas inlet requirements of the calorific value analyzer 6.

[0052] To further optimize the above technical solution, the cooling pipe 91 of the cooler 9 is sleeved outside the gas distribution pipeline 3, and the two ends of the cooling pipe 91 are respectively provided with a water inlet 92 and a water outlet 93. The water inlet 92 and the water outlet 93 allow water to circulate inside the cooling pipe 91, thereby cooling the biomass gas.

[0053] To further optimize the above technical solution, the portion of the gas pipeline 3 located between the main gas pipeline 1 and the filter screen 8 is inclined. The inclination angle is 60°. This inclined design ensures that the water, dust, tar, and other impurities initially purified by the cooler 9 and filter screen 8 can flow back to the main gas pipeline 1, preventing blockage of the cooler 9.

[0054] To further optimize the above technical solution, the range ratio of the pre-purification flow meter 4 and the post-purification flow meter 5 is ≥1.5:1.

[0055] To further optimize the above technical solution, the diameter of the gas distribution pipeline 3 is 1 / 10 to 1 / 5 of the diameter of the main gas pipeline 1. The connection point between the gas distribution pipeline 3 and the main gas pipeline 1 is located downstream of the main flow meter, and the distance between the connection point and the main flow meter 2 is 1 to 2 times the diameter of the gas distribution pipeline 3. The connection position between the gas distribution pipeline 3 and the main gas pipeline 1 ensures that the sampled gas is representative.

[0056] Working principle:

[0057] The biomass fuel gas containing impurities flows from the main gas pipeline 1 through the main flow meter 2, and a portion of the gas is diverted to the purification components through the branch gas pipeline 3. Before purification, the flow meter 4 first measures the volumetric flow rate q1 of the sampled gas containing impurities. Subsequently, the gas passes through the filter screen 8 to remove large dust particles, the cooler 9 to condense tar and moisture, the dust collector 10, the tar remover 11, and the water separator 12 for deep purification, resulting in clean, dry fuel gas. After purification, the flow meter 5 measures its volumetric flow rate q2. Since impurities are removed during the purification process, q2 must be less than q1, and the difference between the two is the volumetric flow rate of impurities in the sampled gas. Through proportional conversion, the volume ratio η of impurities in the main gas pipeline 1 can be obtained. Then, the volume of ineffective impurities is subtracted from the total volumetric flow rate Q1 to obtain the effective fuel gas volume Q corresponding to the calorific value H, and finally, the accurate calorific value E can be calculated.

[0058] Example 2:

[0059] A straw gas metering scenario at a biomass gasification plant, with the following gas parameters:

[0060] The main gas pipeline flow rate Q1 = 1000 Nm 3 / h (volume flow rate including impurities, temperature 80℃, pressure 2kPa)

[0061] For gas pipelines with a diameter of DN50, a bend-tube flow meter (range 0-200Nm) should be selected before purification. 3 / h), q1 = 50 Nm was measured. 3 / h;

[0062] Purification component operating parameters: filter pressure differential ≤100Pa, cooler outlet temperature 35℃, electrostatic precipitator pressure differential ≤200Pa, oil wash circulation rate 2m³ / h. 3 / h, molecular sieve dryer switching cycle 8h;

[0063] After purification, an orifice plate flow meter (range 0-150 Nm) is selected. 3 / h), q2 = 40 Nm was measured. 3 / h; the calorific value of the clean gas measured by the calorific value analyzer is H = 6000 kJ / Nm³. 3

[0064] Calculation process:

[0065] Impurity volume percentage: η = (50-40) / 50 × 100% = 20%

[0066] Effective gas volume: Q = 1000 × (1 - 20%) = 800 Nm 3 / h

[0067] Actual effective heat: E = 800 × 6000 = 4800,000 kJ / h = 1333 kW

[0068] Comparative Test:

[0069] When using a traditional single flowmeter (without deducting impurities), the calculated heat is 1000 × 6000 = 6000,000 kJ / h, which deviates by 25% compared to the result of this invention. After deducting 20% ​​of the impurity volume using this system, the error between the measurement result and the actual combustion test data (4,800,000 kJ / h) is only 0.69%, significantly improving the measurement accuracy.

[0070] Maintenance points:

[0071] Check the filter pressure differential weekly, and activate the backflushing device when the pressure differential exceeds 500Pa.

[0072] The cooler is chemically cleaned monthly to remove scale buildup on the pipe walls;

[0073] The zero points of the pre-purification flow meter and the post-purification flow meter are calibrated quarterly to ensure flow measurement accuracy.

[0074] When the controller detects that q1-q2 continuously exceeds 30% of q1, it issues a purification component blockage alarm, prompting the replacement of the tar removal packing or molecular sieve.

[0075] In summary, this invention constructs a complete metering system of "impurity flow detection - impurity separation - clean flow calibration - calorific value matching calculation" through real-time monitoring by dual flow meters and multi-stage purification treatment. It fundamentally solves the problem of inconsistent flow and calorific value detection conditions in biomass gas metering, and has significant engineering application value and economic benefits.

[0076] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0077] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biomass gas heat metering system, characterized in that, include: The main gas pipeline is equipped with a main flow meter. The gas distribution pipeline is connected to the main gas pipeline; the gas distribution pipeline is equipped with a pre-purification flow meter and a post-purification flow meter, which are respectively located at the inlet and outlet of the gas distribution pipeline. A purification component is located on the gas distribution pipeline between the pre-purification flow meter and the post-purification flow meter; the purification component is used to purify the gas in the gas distribution pipeline. A calorific value analyzer, wherein the calorific value analyzer is located at the outlet end of the gas distribution pipeline; The controller is connected to the main flow meter, the pre-purification flow meter, the post-purification flow meter, and the calorific value analyzer.

2. The biomass gas heat metering system according to claim 1, characterized in that, The purification assembly includes a filter, a cooler, a dust collector, a tar remover, and a water remover arranged sequentially along the gas flow direction.

3. The biomass gas heat metering system according to claim 2, characterized in that, The cooling pipe of the cooler is sleeved outside the gas distribution pipeline, and the two ends of the cooling pipe are respectively provided with a water inlet and a water outlet.

4. The biomass gas heat metering system according to claim 2, characterized in that, The portion of the gas distribution pipeline located between the main gas pipeline and the filter screen is inclined.

5. The biomass gas heat metering system according to claim 1, characterized in that, The range ratio of the pre-purification flow meter to the post-purification flow meter is ≥1.5:

1.

6. The biomass gas heat metering system according to claim 1, characterized in that, The diameter of the gas distribution pipeline is 1 / 10 to 1 / 5 of the diameter of the main gas pipeline. The connection between the gas distribution pipeline and the main gas pipeline is located downstream of the main flow meter, and the distance between the connection and the main flow meter is 1 to 2 times the diameter of the gas distribution pipeline.

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