A method for compensating for gas flow rate, humidity, and density

Abstract

This invention discloses a method for compensating for the humidity and density of coal gas flow rate, belonging to the field of metallurgical automation. The steps include: (1) calculating the humidity coefficient based on the coal gas pressure, temperature, and maximum water vapor pressure in the coal gas; (2) calculating the density coefficient based on pressure and temperature changes; and (3) comparing the density coefficient and humidity coefficient to determine the correction coefficient. Compared with the prior art, this invention can accurately and comprehensively measure the coal gas volume.

Description

Technical Field

[0001] This invention relates to a metallurgical automation method, and more particularly to a method for compensating for gas flow rate, humidity, and density. Background Technology

[0002] Blast furnace gas and converter gas contain a large amount of water vapor. During gas transmission, changes in temperature and humidity cause a significant amount of water to be released and drained through the gas drainer. However, the amount of water drained is not measured, resulting in a large discrepancy between the gas quantity measured on the supply side and the corresponding gas consumption. Therefore, compensation measures are needed to improve the accuracy of actual gas flow measurement. Flow compensation refers to the correction of systematic errors in the flow meter readings.

[0003] Traditional gas metering often uses differential pressure or thermal mass meters. Differential pressure meters measure (Nm³) 3 The formula ( / h) only considers the three main factors affecting the gas flow rate: temperature, pressure, and differential pressure, and only provides compensation for temperature and pressure. While water in the gas is also effectively measured, this water is discharged along the pipeline as temperature and pressure decrease, resulting in significant differences in gas metering between upstream and downstream sides, which cannot effectively guide production. Summary of the Invention

[0004] The technical objective of this invention is to address the shortcomings of the prior art by providing a method for compensating for the humidity and density of gas flow rate. This method calculates the drainage volume during gas transmission and incorporates humidity and density corrections into the gas metering process, thereby achieving accurate gas measurement.

[0005] The technical solution of this invention to solve its technical problem is: a method for compensating for gas flow rate, humidity, and density, characterized by comprising the following steps:

[0006] (1) Calculate the humidity coefficient based on the gas pressure, temperature, and maximum water vapor pressure in the gas:

[0007]

[0008] In the formula: q v1 q v2 ------ These represent the volumetric flow rates of wet gas in states "1" and "2", respectively, in Nm³. 3 / h;

[0009] p1 and p2 represent the absolute pressures in states "1" and "2" respectively, in Pa.

[0010] T1 and T2 represent the thermodynamic temperatures, in K, of state "1" and state "2", respectively.

[0011] φ1 and φ2 represent the relative humidity of the gas in states "1" and "2" respectively, in %;

[0012] p s1max p s1max -------- These represent the maximum possible pressures of water vapor in states "1" and "2", respectively, in Pa;

[0013] Z1 and Z2 represent the gas compressibility coefficients for states "1" and "2" respectively.

[0014] (2) Calculate the density coefficient based on changes in pressure and temperature:

[0015]

[0016] In the formula: ρ1 and ρ2 represent the densities of state "1" and state "2" respectively, in kg / m³. 3 ;

[0017] p1 and p2 represent the absolute pressures in states "1" and "2" respectively, in Pa.

[0018] T1 and T2 represent the thermodynamic temperatures, in K, of state "1" and state "2", respectively.

[0019] (3) Compare the density coefficient and humidity coefficient to determine the correction factor:

[0020] Density coefficient < Humidity coefficient → No correction required for now

[0021] Density coefficient > Humidity coefficient → Correction factor = 1 + (Density correction factor - Humidity correction factor).

[0022] Furthermore, in step (3), the gas generating side deducts the humidity and density influence from state "1" to state "2" in the program; the gas consuming side adds the humidity and density influence from state "1" to state "2" in the program.

[0023] Compared with existing technologies, this invention provides a method for compensating for the flow rate, humidity, and density of coal gas, encompassing temperature and pressure compensation, humidity compensation, and density compensation, thereby accurately and comprehensively measuring the coal gas volume. The improved accuracy of coal gas flow rate measurement can effectively guide production, reduce heat energy waste, and provide assurance for enterprises in energy conservation, emission reduction, and cost accounting. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments.

[0025] For the purposes of the following detailed description, it should be understood that the invention may take various alternative variations and sequences of steps unless explicitly stated otherwise. Furthermore, except in any operational instance or where otherwise indicated, all figures representing quantities of ingredients as used, for example, in the specification and claims, should in all cases be understood to be modified by the term “about.” At least, and without attempting to limit the application of the principle of equivalents to the scope of the claims, each numerical parameter should be understood at least according to the number of significant figures reported and by applying common rounding techniques.

[0026] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​described in the specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement.

[0027] It should also be understood that any range of values ​​stated herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0028] In this application, unless otherwise specified, the use of the singular includes the plural and the plural encompasses the singular. Additionally, in this application, unless otherwise expressly stated, the use of "or" means "and / or," even if "and / or" may be explicitly used in certain circumstances. Furthermore, in this application, unless otherwise specified, the use of "a" or "an" means "at least one / a." For example, "an" first material, "an" coating composition, etc., refer to one or more of any of these items.

[0029] This invention includes a method for compensating for the humidity and density of gas flow rate. It incorporates humidity and density calculation formulas into the conventional temperature and pressure compensation calculation program to ensure that the measurement data is true and accurate.

[0030] 1. Calculate the humidity coefficient based on the gas pressure, temperature, and maximum water vapor pressure in the gas:

[0031]

[0032] In the formula: q v1 q v2 ------ These represent the volumetric flow rates of wet gas in states "1" and "2", respectively, in Nm³. 3 / h;

[0033] p1 and p2 represent the absolute pressures in states "1" and "2" respectively, in Pa.

[0034] T1 and T2 represent the thermodynamic temperatures, in K, of state "1" and state "2", respectively.

[0035] φ1 and φ2 represent the relative humidity of the gas in states "1" and "2" respectively, in %;

[0036] p s1max p s1max -------- These represent the maximum possible pressures of water vapor in states "1" and "2", respectively, in Pa;

[0037] Z1 and Z2 represent the gas compressibility coefficients for states "1" and "2" respectively.

[0038] 2. Calculate the density coefficient based on changes in pressure and temperature:

[0039] Based on the Clapeyron equation (ideal gas equation) PV=nRT, V=m / ρ, the density coefficient is derived as follows:

[0040]

[0041] In the formula: ρ1 and ρ2 represent the densities of state "1" and state "2" respectively, in kg / m³. 3 ;

[0042] p1 and p2 represent the absolute pressures in states "1" and "2" respectively, in Pa.

[0043] T1 and T2 represent the thermodynamic temperatures, in K, of state "1" and state "2", respectively.

[0044] 3. Compare the density coefficient and humidity coefficient to determine the correction factor:

[0045] Density coefficient < Humidity coefficient → No correction required for now

[0046] Density coefficient > Humidity coefficient → Correction factor = 1 + (Density correction factor - Humidity correction factor)

[0047] In the optimization scheme, the humidity and density effects of states "1" to "2" are deducted from the program on the gas generating side; the humidity and density effects of states "1" to "2" are added to the program on the gas consuming side.

[0048] The invention will be further illustrated below with reference to application examples.

[0049] On February 10, 2022, the company built a new 450m³ unit. 2The sintering denitrification project requires blast furnace gas as fuel. Before commissioning, a Barrel flow meter was installed on the equipment pipeline as a gas consumption meter. However, the gas flow rate of this meter is affected by changes in humidity and density due to temperature and pressure variations from the TRT generator set outlet to the sintering machine desulfurization equipment section, which can lead to inaccurate gas consumption measurement. Therefore, at the request of the energy management unit, the humidity and density influence coefficient from the TRT generator set outlet to the sintering machine desulfurization equipment section should be calculated using process accounting methods to compensate for the meter reading.

[0050] The specific calculation process is as follows:

[0051] 1. Data statistics and query:

[0052]

[0053] 2. Substitute into formula (1) to calculate the humidity coefficient.

[0054] Humidity coefficient, which is the coefficient of gas consumption after adding humidity correction and gas consumption without adding humidity correction.

[0055]

[0056] The result,

[0057] 3. Substitute into formula (2) to calculate the density coefficient.

[0058]

[0059] The result,

[0060] 4. Comparison of the effects of humidity and density changes

[0061] Basis: Density coefficient > Humidity coefficient;

[0062] Therefore: Correction factor = 1 + (density correction factor - humidity correction factor) = 1 + (0.96165 - 0.88283) = 1.07882.

[0063] 5. According to the correction principle, multiply the metering end of the denitrification equipment by 1.07882 to obtain the actual gas consumption from the TRT outlet to the user end after the influence of humidity and density changes.

[0064] It should be noted that the specific embodiments of the present invention have been described in detail. For those skilled in the art, various obvious changes made to it without departing from the spirit and scope of the present invention are within the protection scope of the present invention.

Claims

1. A method of gas flow humidity, density compensation for coal gas, characterized in that: The method comprises the following steps: (1) According to the coal gas pressure, temperature and maximum water vapor pressure in the coal gas, the humidity coefficient is calculated: where: q v1 , q v2 --- represent the volumetric flow rate of wet gas in states "1" and "2", respectively, Nm 3 / h; p1, p2----respectively the absolute pressure of state "1" and state "2", Pa; T1, T2----respectively represent the thermodynamic temperature of state "1" and state "2", K; φ1, φ2----respectively represent the relative humidity of state "1" and state "2", %; p s1max 、p s1max -------- maximum possible pressure of water vapor in state "1" and state "2", respectively, Pa; Z1, Z2----respectively represent the gas compression coefficient of state "1" and state "2"; (2) According to the pressure and temperature change, the density coefficient is calculated: wherein: p1, p2— denote the densities of the states "1" and "2", respectively, kg / m3 3 ; p1, p2----respectively the absolute pressure of state "1" and state "2", Pa; T1, T2----respectively represent the thermodynamic temperature of state "1" and state "2", K; (3) The density coefficient and the humidity coefficient are compared to determine the correction coefficient: Density coefficient < humidity coefficient → no correction for the time being Density coefficient > humidity coefficient → correction coefficient = 1 + (density coefficient - humidity coefficient); Multiply the correction coefficient at the metering end as the real amount of coal gas consumption after the influence of humidity and density change; The coal gas generation side deducts the humidity and density influence amount from state "1" to state "2" in the program; the coal gas consumption side adds the humidity and density influence amount from state "1" to state "2" in the program.

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