阅读说明：本技术 一种燃气能量计量流量计 (Gas energy metering flowmeter ) 是由 李诗华 任海军 徐荣华 王文军 刘金勇 于 2020-11-19 设计创作，主要内容包括：本发明涉及一种燃气能量计量流量计,其特征在于,包括体积流量测量单元,用于测量得到天然气的体积流量Q_n；热值检测单元,用于检测天然气单位发热量H,包括光学传感模块、声速传感模及计算模块；计算单元,用于计算得到天然气的能量E,E＝Q_n×H。本发明提供的一种流量计所采用的计算能量E的计算方法较为简单,因此可以实现对天然气能量E快速、准确的计量。(The invention relates to a gas energy metering flowmeter which is characterized by comprising a volume flow measuring unit for measuring and obtaining the volume flow Q of natural gas n (ii) a The heat value detection unit is used for detecting the unit heating value H of the natural gas and comprises an optical sensing module, a sound velocity sensing module and a calculation module; a calculating unit for calculating and obtaining the energy E, E ═ Q of the natural gas n XH. The method for calculating the energy E adopted by the flowmeter is simple, so that the energy E of the natural gas can be quickly and accurately measured.)

1. A gas energy metering flowmeter, comprising:

a volume flow measuring unit for measuring the volume flow Q of the natural gas_n；

The heat value detection unit is used for detecting the unit calorific capacity H of the natural gas and comprises an optical sensing module, a sound velocity sensing module and a calculation module, wherein:

the optical sensing module is used for detecting the optical heat value H of the obtained natural gas_O，H_O＝H_T-X, wherein H_TRepresenting theoretical calorific value, X representing optical impurity interference;

the sound velocity sensing module is used for detecting and obtaining the heat conduction calorific value H of the natural gas_hc，H_hc＝H_T-Y, wherein H_TExpressing theoretical heat value, Y expresses heat conduction impurity interference, Y is equal to aX, and a is a constant coefficient;

the calculation module obtains the unit heating value H of the natural gas through the following formula (1):

H＝H_O-(H_O-H_hc)÷(1-a) (1)

a calculating unit for calculating and obtaining the energy E, E ═ Q of the natural gas_n×H。

2. The gas energy meter according to claim 1, wherein the volume flow measuring unit comprises a volume flow measuring module and a correction module, wherein:

volumetric flow measurementThe module being arranged to measure an uncorrected volume flow Q_g；

The correction module is based on the following formula (2) to the volume flow Q_gCorrecting to obtain the volume flow Q_n：

In the formula (2), P_gIndicating the absolute pressure, P, of the natural gas measured by the correction module_nDenotes standard atmospheric pressure, T_nDenotes the absolute temperature, T, of the natural gas at standard conditions_gIndicating the absolute temperature, Z, of the natural gas measured by the correction module_nDenotes the medium compression factor, Z, in the natural gas standard state_gThe medium compression coefficient under the natural gas working condition is shown.

3. A gas energy metering flowmeter as set forth in claim 2 wherein said computing unit is integrated into said correction module.

4. The gas energy metering flowmeter as recited in claim 3, wherein said calorific value detection unit sends the obtained unit calorific value H of said natural gas to said correction module through a data line, and said correction module outputs said energy E.

5. The gas energy metering flowmeter of claim 4, further comprising an inlet unit, a gas filtering unit and a pressure reducing unit, wherein the natural gas enters the gas filtering unit through the inlet unit, impurities in the natural gas are filtered by the gas filtering unit, and the filtered natural gas is reduced in pressure to a target pressure value through the pressure reducing unit and then is sent to the heat value detecting unit and the volume flow measuring module.

Technical Field

The invention relates to a flowmeter for measuring natural gas energy, belonging to flowmeters.

Background

With the continuous increase of natural gas consumption scale in China, the dependence of natural gas on the outside is continuously increased, and the sources of natural gas tend to be diversified after natural gas pipe network facilities are independently opened, so that the contradiction disputes caused by the mixed transportation of natural gas from different sources in the same pipe network are increasingly prominent due to the non-uniform metering units.

Among the many ways of measuring trade, energy measurement is the most popular way of trading settlement for natural gas internationally. Most countries internationally settle accounts by adopting an energy metering mode, and relevant laws and regulations, energy policies and price policies of natural gas energy metering are established. While natural gas in China is mainly measured by volume, the dependence of natural gas on foreign matters is gradually improved along with the development of domestic economy, the types of related gas sources of a natural gas pipe network are more and more, the components of different types of natural gas are different, and the energy generation amount per unit volume is greatly different. Therefore, the conversion of the natural gas metering mode from volume metering to energy metering is urgent. Meanwhile, the volume metering mode is not beneficial to the connection of China with international convention in the international trade of natural gas.

Taking Xiqidong defeated Shaanjing first line and Shaanjing second line as examples, the former volume energy generation can reach 8500 kilocalories, while the latter is 7900 kilocalories, the difference of the volume energy generation is 600 kilocalories, and the use of the volume metering mode easily causes the quality of the gas used by the user to have great difference.

Compared with volume metering, energy metering can fully reflect the real value of natural gas as fuel, and more stable products and services can be provided for users. Moreover, the energy metering is an effective means for reducing the supply and sale rate of the natural gas. Along with the continuous increase of gas consumption in China, the difference between the gas intake amount and the gas sales amount is also increased, so that the benefits of consumers are damaged, and the loss of natural gas companies is also caused. The energy metering can realize scientific and fair accurate metering of the natural gas, and is the key for reducing the common sale difference rate of the natural gas.

Disclosure of Invention

The invention aims to: provided is a meter device capable of realizing natural gas energy metering.

In order to achieve the above object, the present invention provides a gas energy metering flowmeter, including:

a volume flow measuring unit for measuring the volume of the obtained natural gasFlow rate Q_n；

The heat value detection unit is used for detecting the unit calorific capacity H of the natural gas and comprises an optical sensing module, a sound velocity sensing module and a calculation module, wherein:

the optical sensing module is used for detecting the optical heat value H of the obtained natural gas_O，H_O＝H_T-X, wherein H_TRepresenting theoretical calorific value, X representing optical impurity interference;

the sound velocity sensing module is used for detecting and obtaining the heat conduction calorific value H of the natural gas_hc，H_hc＝H_T-Y, wherein H_TExpressing theoretical heat value, Y expresses heat conduction impurity interference, Y is equal to aX, and a is a constant coefficient;

the calculation module obtains the unit heating value H of the natural gas through the following formula (1):

H＝H_o-(H_o-H_hc)÷(1-a) (1)

a calculating unit for calculating and obtaining the energy E, E ═ Q of the natural gas_n×H。

Preferably, the volume flow measurement unit includes a volume flow measurement module and a correction module, wherein:

the volume flow measurement module is used for measuring and obtaining uncorrected volume flow Q_g；

The correction module is based on the following formula (2) to the volume flow Q_gCorrecting to obtain the volume flow Q_n：

In the formula (2), P_gIndicating the absolute pressure, P, of the natural gas measured by the correction module_nDenotes standard atmospheric pressure, T_nDenotes the absolute temperature, T, of the natural gas at standard conditions_gIndicating the absolute temperature, Z, of the natural gas measured by the correction module_nDenotes the medium compression factor, Z, in the natural gas standard state_gThe medium compression coefficient under the natural gas working condition is shown.

Preferably, the calculation unit is integrated in the correction module.

Preferably, the calorific value detection unit sends the obtained unit calorific value H of the natural gas to the correction module through a data line, and the correction module outputs the energy E.

Preferably, the natural gas flow meter further comprises an air inlet unit, a gas filtering unit and a decompression unit, wherein the natural gas enters the gas filtering unit through the air inlet unit, impurities in the natural gas are filtered by the gas filtering unit, and the filtered natural gas is decompressed to a target pressure value through the decompression unit and then is sent to the heat value detection unit and the volume flow measurement module.

The method for calculating the energy E adopted by the flowmeter is simple, so that the energy E of the natural gas can be quickly and accurately measured.

Drawings

FIG. 1 is a schematic illustration of a gas energy metering flow meter as disclosed in the examples;

FIG. 2 is a schematic internal structure diagram of the gas energy metering flowmeter disclosed in the embodiment;

fig. 3 is a schematic diagram of a heat value meter in the example, in which:

1-a flow meter, 2-a volume corrector, 3-an air inlet joint, 4-an air inlet valve, 5-a filter, 6-a pressure reducing valve, 7-a heat value meter, 8-a one-way valve, 9-RS485 communication cables, 10-an LED light source, 11-a plane mirror, 12-a convex mirror, 13-interference fringes, 14-a prism, 15-a parallel mirror, 16-a sound source, 17-a receiver, 18-a fuel gas inlet and 19-a fuel gas outlet.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

As shown in fig. 1 and fig. 2, the gas energy metering flowmeter disclosed in this embodiment includes a volume corrector 1 (the EVC intelligent volume corrector is adopted in this embodiment), a flowmeter 2, an air inlet joint 3, an air inlet valve 4, a filter 5, a pressure reducing valve 6, a heat value meter 7, a check valve 8, and an RS485 communication cable 9.

The air inlet joint 3 is connected with the shell of the flowmeter 2, and after the natural gas enters the flowmeter 2, the natural gas also enters the filter 5 through the air inlet joints 3 and 4. Filtering gas impurities in the natural gas by a filter 5, decompressing the filtered natural gas to 2-10KPa by a decompression valve 6, and entering a heat value instrument 7, wherein the heat value instrument 7 measures to obtain the unit heating value H (the unit is MJ/Nm) of the natural gas³). The heat value meter 7 performs data communication through a modbus protocol (including RS485 and RS232), and transmits the unit heating value H of the natural gas to the volume corrector 1. The volume corrector 1 simultaneously outputs the volume flow Q according to the flowmeter 2_gAnd calculating the energy E (unit is MJ) of the natural gas, and displaying the calculated result on a liquid crystal screen.

In principle, the energy E of natural gas is the product of the volumetric flow rate of natural gas and the unit calorific value. That is, the energy of natural gas depends on two factors: natural gas volume flow and unit heating value. The energy flow metering of the natural gas is completed by two unrelated measurements, namely measurement of volume or mass flow and measurement of volume or mass calorific value, and the two measurements are synthesized to calculate the energy of the natural gas, as shown in the following formula (1):

E＝Q_n×H (1)

in the formula (1), Q_nVolume flow or mass flow in Nm of natural gas standard state³Or kg.

Volume flow rate Q of natural gas_nThe measurement is carried out by adopting a gas waist wheel flowmeter, a gas turbine flowmeter or a gas ultrasonic flowmeter. This embodiment is illustrated as a gas roots meter.

With the flow of gas, a differential pressure is generated at the inlet and outlet of the meter, and the differential pressure acts on a waist wheel connected through a high-precision synchronous gear to generate a torque. This torque in turn acts on a pair of lumbar wheels causing them to rotate. There is no contact between the housing and the lumbar. The metering chamber thus formed between the housing and the lumbar wheel is periodically filled and emptied. The number of revolutions of the lumbar wheel is proportional to the volume of gas passing through the meter. The number of revolutions of the rotor is converted into a pulse signal by a magnetoelectric conversion device.

In the embodiment, a corrector 1 is configured on the basis of a precision manufacturing mechanical watch, and the corrector 1 consists of a temperature and pressure detection channel and a processing unit and is provided with an input interface and an output interface. The processing unit in the corrector 1 performs volume conversion according to a gas equation and automatically performs compression factor correction, wherein the gas equation is shown as the following formula (2):

in the formula (2), P_gRepresenting the absolute pressure of the natural gas measured by the correction module in kPa;

P_nindicating standard atmospheric pressure, 101.325 kPa;

T_nrepresents the absolute temperature in the standard state of natural gas, 293.15K (20 ℃);

T_grepresenting the absolute temperature of the natural gas measured by the correction module;

Z_nrepresenting the medium compression coefficient of the natural gas in a standard state;

Z_gthe medium compression coefficient under the natural gas working condition is shown.

Note: for natural gas Z_n/Z_g＝(FZ)²FZ is a super compression factor and is calculated according to a formula in a standard SY/T6143-1996 of China oil and gas general company.

As shown in fig. 3, the heat value meter 7 in the present embodiment employs a combined calculation method of optical heat value detection and thermal conduction heat value detection. The disturbance of the impurity component to the optical heat value detection and the disturbance of the impurity component to the heat conduction heat value detection have an approximate constant a, then:

optical calorific value H obtained by optical calorific value detection_O，H_O＝H_T-X, wherein H_TRepresenting the theoretical calorific value and X representing the optical impurity interference.

Heat conduction calorific value H obtained by heat conduction calorific value detection_hc，H_hc＝H_T-Y, wherein H_TRepresents the theoretical calorific value, Y represents the thermal conduction impurity interference, and Y ═ aX.

Final work-up gives the following formula (3):

H＝H_O-(H_O-H_hc)÷(1-a) (3)

the volume corrector 1 calculates the energy E of the natural gas by using the above formulas (1), (2) and (3), and displays the energy E on the liquid crystal screen.