System for realizing dynamic monitoring of dendritic steam pipe network through soft measurement

Abstract

The invention discloses a system for achieving dynamic monitoring of a dendritic steam pipe network through soft measurement. The method comprises the steps that 1, flow meters are arranged at the head end and the tail end of a main pipe of the dendritic steam pipe network respectively; a pressure sensor is arranged on each steam utilization node of the dendritic steam pipe network; 2, forming a pressure vector according to the detection pressure of each steam utilization node and the assignment of the pressure of each intermediate node; 3, the flow of each pipe section is obtained through calculation according to the pressure vectors; 4, changing the assignment of the pressure of each intermediate node, and continuously iterating until an iteration termination condition is reached, so as to obtain a monitoring flow value of each pipe section; compared with an existing system, the installation number of the steam flow meters is greatly reduced, and due to the fact that the steam flow meters are high in price, the installation cost and the equipment cost are greatly reduced after the installation number is reduced; according to the invention, the low-price pressure sensor and a small number of flowmeters are used for detecting the flow through modeling, so that the reliable and comprehensive monitoring of the whole system is realized.

Description

Technical Field

[0001] The invention belongs to the field of dynamic monitoring of a dendritic steam pipe network, and in particular relates to a system for realizing dynamic monitoring of a dendritic steam pipe network through soft measurement. Background Art

[0002] Soft measurement technology organically combines production process knowledge, applies computer technology to important variables that are difficult to measure or temporarily unmeasurable, selects other easily measurable variables, and infers or estimates them by forming certain mathematical relationships, thereby replacing the functions of hardware with software.

[0003] Real-time monitoring of steam systems generally requires attention to parameters such as steam temperature, pressure, and flow at the collection points. Temperature and pressure sensors are relatively inexpensive and can be installed wherever needed. However, flow meters, used for steam flow collection, are generally very expensive and cannot be installed in large numbers in real projects, unlike temperature and pressure sensors. When monitoring the flow status of the entire steam system, nodes without flow meters are considered blind spots, preventing a complete understanding of the steam system's status.

[0004] The dynamic monitoring of the existing steam pipeline network is achieved based on the meter sensors installed in the pipeline network. To ensure the safe and efficient operation of the steam system, the existing real-time monitoring of the steam system is achieved by comprehensively installing meter sensors, which increases the cost of system construction. In addition, the current meter monitoring system does not meter the parameters of non-critical nodes in the pipeline network, and this part of the data is missing. Summary of the Invention

[0005] The purpose of the present invention is to provide a system for dynamic monitoring of branched steam pipe networks through soft measurement, so as to solve the problems of high cost caused by comprehensive installation of meter sensing devices for dynamic monitoring of existing steam pipe networks, and the lack of meter sensing devices for parameters of non-critical nodes of the pipe network, which leads to the loss of data in this part.

[0006] The present invention adopts the following technical solution: a system for realizing dynamic monitoring of a branched steam pipe network through soft measurement, comprising:

[0007] Step 1: Flow meters are installed at the head end and tail end of the main pipe of the branched steam pipe network; and pressure sensors are installed at each steam consumption node of the branched steam pipe network; the pressure sensors are used to detect the pressure at the corresponding position;

[0008] Step 2: A pressure vector is formed based on the detected pressure of each steam-using node and the pressure of each intermediate node;

[0009] Step 3: Calculate the flow rate of each pipe section based on the pressure vector;

[0010] Step 4: Change the pressure assigned to each intermediate node and iterate continuously until the iteration termination condition is reached to obtain the monitored flow value of each pipe section.

[0011] Furthermore, the flow rate of each pipe section in step 3 is calculated as follows:

[0012]

[0013] Where G n is the flow rate of the nth pipe section; d n is the diameter of the nth pipe section; n is the resistance coefficient of the nth pipe section; l n is the length of the nth pipe segment; g is the acceleration due to gravity, which is 9.8 kg / s 2 ;ΔP n It is the difference between the starting pressure and the ending pressure of the nth pipe segment.

[0014] Furthermore, the iterative method in step 4 is:

[0015]

[0016] Among them, P i-1 It is the pressure vector composed of the detection pressure of each steam node and the pressure assignment of each intermediate node; i The pressure vector is composed of the pressure assigned to each intermediate node and the detection pressure of each steam-consuming node;

[0017] Among them, Q1 i-1 =∑f x (P i-1 ); x is the number of the user node.

[0018] Furthermore, the iteration termination condition in step 4 is:

[0019] (Q m -Q a ) / Q a ≤5%

[0020] Where Q m Iteratively calculate the flow value of the end user node, Q a It is the actual flow value measured by the flow meter at the end user node.

[0021] The beneficial effects of the present invention are:

[0022] Compared with existing systems, the present invention significantly reduces the number of steam flow meters installed. Since these steam flow meters are expensive, the installation cost and equipment cost are significantly reduced after the number of installations is reduced. The present invention uses low-cost pressure sensors and a small number of flow meters to detect flow through modeling, achieving reliable and comprehensive monitoring of the entire system.

[0023] The monitoring system of the existing technology generally only installs flow meters, thermometers, pressure gauges and other sensors at the user's location and some key points, and does not install them at other remaining nodes, resulting in the lack of monitoring parameters in these areas and the inability to fully grasp the operating status of the entire system. The present invention achieves more comprehensive and complete monitoring efficiency through modeling methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the branched steam pipe network of Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The present invention discloses a system for realizing dynamic monitoring of a branched steam pipe network through soft measurement, comprising:

[0027] Step 1: Flow meters are installed at the head end and tail end of the main pipe of the branched steam pipe network; and pressure sensors are installed at each steam consumption node of the branched steam pipe network; the pressure sensors are used to detect the pressure at the corresponding position;

[0028] Step 2: A pressure vector is formed based on the detected pressure of each steam-using node and the pressure of each intermediate node;

[0029] Step 3: Calculate the flow rate of each pipe section based on the pressure vector;

[0030] Step 4: Change the pressure assigned to each intermediate node and iterate continuously until the iteration termination condition is reached to obtain the monitored flow value of each pipe section.

[0031] The calculation formula for the flow rate of each pipe section in step 3 is:

[0032]

[0033] Where G n is the flow rate of the nth pipe section; d n is the diameter of the nth pipe section; n is the resistance coefficient of the nth pipe section; l n is the length of the nth pipe segment; g is the acceleration due to gravity, which is 9.8 kg / s 2 ;ΔP n It is the difference between the starting pressure and the ending pressure of the nth pipe segment.

[0034] The iterative method in step 4 is:

[0035] P i =P i-1 -Q1 i-1 / Qi-1 1 ’ ;

[0036] Among them, P i-1 It is the pressure vector composed of the detection pressure of each steam node and the pressure assignment of each intermediate node; i The pressure vector is composed of the pressure assigned to each intermediate node and the detection pressure of each steam-consuming node;

[0037] Among them, Q1 i-1 =∑f x (P i-1 ); x is the number of the user node.

[0038] The iteration termination condition in step 4 is:

[0039] (Q m -Q a ) / Q a ≤5%

[0040] Where Q m Iteratively calculate the flow value of the end user node, Q a It is the actual flow value measured by the flow meter at the end user node.

[0041] Example 1

[0042] The schematic diagram of the branched steam pipe network in this embodiment is as follows Figure 1 As shown, ① is the node number; 1 is the pipe segment number; there are m nodes and n pipe segments in total.

[0043] Node ① is the steam supply point, and the temperature, pressure, and flow parameters of this node are recorded as T1, P1, and Q1;

[0044] Nodes ③, ⑤, ⑦, ... The temperature, pressure and flow rate of the nodes are recorded as T3, P3, Q3, T5, P5, Q5, T7, P7, Q7, ... T m 、P m , Q m ,

[0045] Nodes ②, ④, ⑥, etc. are intermediate nodes, and the temperature, pressure, and flow rate of the nodes are recorded as T2, P2, Q2, T4, P4, Q4, T6, P6, Q6, etc. respectively;

[0046] The flow rates of pipe sections 1, 2, 3, ...n are recorded as G1, G2, G3, ...G n ;

[0047] Flow meter: Q1 is the flow meter for the steam node at the head end, Q a The flow meter for the final steam node;

[0048] Pressure sensor: P1, P3, P5, P7, ...P m Representing nodes ①, ③, ⑤, ⑦, etc. The pressure sensor monitors the pressure;

[0049] The diameters d of pipe sections 1, 2, 3, ...n in the pipe network are recorded as: d1, d2, d3, ...d n ;

[0050] The lengths l of pipe sections 1, 2, 3, ...n in the pipe network are denoted as: l1, l2, l3, ...l n ;

[0051] The resistance coefficient of pipe section n is λ n , the pressure loss is ΔP n ,have:

[0052]

[0053] but:

[0054]

[0055] Known operating data of the pipeline network at a certain time:

[0056] Flow rate: Q1, Q a

[0057] Pressure: P1, P3, P5, P7, ...P m ;

[0058] Data to be solved:

[0059] Flow rate: Q3, Q5, Q7…Q m , the intermediate node traffic Q2, Q4, Q6... is 0;

[0060] Pressure: P2, P4, P6, ...;

[0061] According to the mass conservation equation: Q1=Q3+Q5+Q7+…+Q m

[0062] All node pressures P1, P2, P3, ... P m Forming a pressure vector P,

[0063] Assign the initial value of P2 to each unknown pressure P2, P4, P6, ... 0 、P4 0 、P6 0 ,…, vector P is denoted as P 0 ;

[0064] There is: G3=f3(P 0), G5=f5(P 0 ), G7=f7(P 0 ),…G m =f m (P 0 );

[0065] For steam pipe section: G3 = Q3, G5 = Q5, G7 = Q7, ...G m =Q m ;

[0066] Then: Q1 0 =f3(P 0 )+f5(P 0 )+f7(P 0 )+…+f m (P 0 );

[0067] To G n =f(P) to find the derivative,

[0068] Q 0 1 ’ =f3 ’ (P 0 )+f5 ’ (P 0 )+f7 ’ (P 0 )+…+f m, (P 0 );

[0069] Let P 1 The value of unknown pressure P2, P4, P6, ... is P2 1 、P4 1 、P6 1 ,…;

[0070] Author: P 1 =P 0 -Q1 0 / Q 0 1 ’ , calculate P2 1 、P4 1 、P6 1 ,…,

[0071] Perform iterative calculation in the above manner. Assume that after iterating i times, (Q m -Q a ) / Q a ≤5%, calculation ends.

[0072] The last calculation results in data P2 i 、P4 i 、P6i ,…, substitute into formula G n =f(P), calculate Q3 i 、Q5 i 、Q7 i …Q m i ;

[0073] The above calculation data P2 i 、P4 i 、P6 i ,…,Q3 i 、Q5 i 、Q7 i …Q m i The data is transmitted to the monitoring system to complete the online soft measurement of steam network flow.

[0074] The above description is only 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 in the scope of protection of the present invention.

Claims

1. A system for dynamic monitoring of a branched steam pipe network by soft measurement, characterized in that: include: Step 1: flow meters are respectively installed at the head end and tail end of the main pipe of the branch steam pipe network; A pressure sensor is provided at each steam-using node of the branch-shaped steam pipe network; the pressure sensor is used to detect the pressure at the corresponding position; Step 2: A pressure vector is formed according to the detected pressure of each steam-using node and the pressure of each intermediate node; Step 3: Calculate the flow rate of each pipe section according to the pressure vector; Step 4: Change the pressure assigned to each intermediate node and iterate continuously until the iteration termination condition is reached to obtain the monitored flow value of each pipe section.

2. A system for dynamic monitoring of a branched steam pipe network by soft measurement according to claim 1, characterized in that: The calculation formula for the flow rate of each pipe section in step 3 is: In the formula, G n is the flow rate of the nth pipe section; d n is the diameter of the nth pipe section; n is the resistance coefficient of the nth pipe section; l n is the length of the nth pipe segment; g is the acceleration due to gravity, which is 9.8 kg / s 2 ; ΔP n It is the difference between the starting pressure and the ending pressure of the nth pipe segment.

3. The system for realizing dynamic monitoring of branched steam pipe network by soft measurement according to claim 1, characterized in that: The iterative method in step 4 is: P i =P i-1 -Q1 i-1 / Q i-1 1 ’ ; Among them, P i-1 It is a pressure vector composed of the detection pressure of each steam node and the pressure of each intermediate node; i The pressure vector is composed of the pressure assigned to each intermediate node and the detected pressure of each steam-using node; Among them, Q1 i-1 =∑f x (P i-1 ); x is the number of the user node.

4. The system for realizing dynamic monitoring of branched steam pipe network by soft measurement according to claim 1, characterized in that: The iteration termination condition in step 4 is: (Q m -Q a ) / Q a ≤5% In the formula, Q m Iteratively calculate the flow value of the end user node, Q a It is the actual flow value measured by the flow meter at the end user node.

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