Optimization calculation method for pipeline thermal insulation layer of steam pipe network

Abstract

The invention discloses a steam pipe network thermal insulation layer optimization calculation method, which comprises a parameter acquisition module, a pipeline operation calculation module and a thermal insulation layer optimization module. The parameter acquisition module is responsible for deploying a sensor at the starting end of a target pipeline so as to acquire parameters such as pressure, temperature and flow of a pipeline inlet, and the measured parameters and related design parameters of the target pipeline serve as input values of an optimization calculation method; the pipeline operation calculation module is used for calculating operation parameters of a target pipeline, performing thermal-hydraulic coupling calculation by combining the input values with related design parameters of the target pipeline to obtain the operation parameters of the pipeline, and providing a basis for setting a thermal insulation layer; and the thermal layer optimization module is used for performing optimization calculation on the thermal insulation layer of the target pipeline, and performing optimization calculation on the thermal insulation layer through the operating parameters obtained by the steam thermal power-hydraulic power coupling calculation model by iterating the thickness of the thermal insulation layer based on the life cycle model of the steam pipe network. By means of the method, the heat preservation structure can be optimized according to needs. The thermal insulation material and the thermal insulation structure are adjusted according to different steam heat supply network application scenes, accurate optimization is achieved, thermal insulation material loss and pipeline investment cost are reduced, and the energy utilization rate is effectively increased.

Description

Technical Field

[0001] This patent relates to the field related to steam pipe network insulation design, specifically a method for optimizing the calculation of the steam pipe network insulation layer. Background Art

[0002] Steam pipe networks are an integral part of industrial production and life. Their insulation design offers significant energy-saving potential. Improper design not only results in significant heat loss but also leads to higher primary energy consumption. Traditional steam pipe insulation is applied in a crude manner, primarily to reduce heat loss during operation. This often results in excessively thick insulation, failing to achieve the goals of low cost and low energy consumption throughout the pipe network's lifecycle. Summary of the Invention

[0003] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0004] To address the above shortcomings, the present invention aims to provide a steam pipe network insulation layer optimization calculation method. The method optimizes the pipe network insulation thickness with the goal of minimizing total cost, thereby achieving the lowest total cost over the life cycle.

[0005] The present invention provides a method for optimizing and calculating the thermal insulation layer of a steam pipe network, comprising: a parameter acquisition module, a pipeline operation calculation module, and an insulation layer optimization module. The parameter acquisition module measures the pipe inlet parameters based on a sensor provided at the starting end of a target pipe, and uses the measured parameters and the relevant design parameters of the target pipe as input values ​​for the optimization calculation method; the pipe operation calculation module calculates the operating parameters of the target pipe, performs a thermodynamic-hydraulic coupling calculation based on each input value combined with the relevant design parameters of the target pipe, obtains the pipe operating parameters, and provides a basis for setting the insulation layer; the insulation layer optimization module optimizes the insulation layer of the target pipe, and performs an insulation layer optimization calculation based on the steam pipe network life cycle model, iterates the insulation layer thickness, and uses the operating parameters obtained from the steam thermodynamic-hydraulic coupling calculation model to perform the insulation layer optimization calculation.

[0006] The beneficial effects of the above-mentioned technical prevention are as follows: a parameter acquisition module is set up to collect data at the inlet of the target pipeline, and the relevant design parameters of the target pipeline are used as input values, and the pipeline operation parameters are calculated according to the steam thermal-hydraulic coupling model; the insulation layer optimization module relies on the steam pipeline life cycle model to comprehensively analyze the initial investment cost and pipeline operation cost of the target pipeline. At the same time, according to the actual operating conditions, the insulation thickness is iteratively optimized, and the pipeline insulation layer structure is simulated and calculated when the optimal insulation thickness, that is, the optimal economic thickness, is achieved, thereby optimizing the pipeline network insulation structure, meeting the heat transmission demand while reducing energy consumption.

[0007] Furthermore, the target pipeline related design parameters include pipeline inclination, pipeline diameter, pipeline length, pipeline operating life, and pipeline annual operating hours.

[0008] Furthermore, the pipeline operation calculation module is based on the steam thermal-hydraulic coupling model, which combines the energy, momentum and continuity equations, takes into account the influence of condensed water in the steam pipeline, and the influence of the thermal-hydraulic effect of the pipeline network on the pipeline temperature and pressure.

[0009] Furthermore, the calculation equation of the method for calculating pipeline operation parameters of the steam thermal-hydraulic coupling model is as follows:

[0010]

[0011] Where: ρ is the steam density, kg / m 3 ; v is the steam velocity, m / s; P is the steam pressure, Pa; g is the acceleration due to gravity, g = 9.8 m / s 2 ; θ is the angle between the pipe and the horizontal plane, (°); λ is the friction resistance coefficient; D is the inner diameter of the pipe, m; h is the specific enthalpy, J / kg; K is the heat transfer coefficient of the pipe, W / (m 2 ·K); T is steam temperature, ℃; T0 is steam temperature, ℃; m c is the steam drainage mass loss (kg / (m3·s)); Z is the pipe height, m.

[0012] Furthermore, the pipeline life cycle model calculates the initial investment cost of the target pipeline using the following equation:

[0013] C n1 =C gsg ((d1+2δ+2δ1) 2 -(d+2δ) 2 )πL / 4τ

[0014]

[0015] C n =C n1 +C n2

[0016] Where: C n1 、C n2 The corresponding investment cost of insulation layer construction and civil construction cost, RMB; C gsg The cost of insulation layer per cubic meter, RMB / m3; C S is the civil construction cost per unit volume, RMB / kg; H is the buried depth of the pipeline center, m; d1 is the inner diameter of the steam pipeline, m; δ is the thickness of the steam pipeline, m; δ i is the thickness of the i-th insulation layer. Considering that in actual production, the insulation thickness is manufactured according to certain specifications, δ i Take 5 or multiples of 5, m; τ is the operation life of the pipeline network, years; L is the length of the pipeline, m; C n is the initial investment cost, yuan.

[0017] Furthermore, the pipeline life cycle model calculates the target pipeline operating cost using the following equation:

[0018]

[0019] Where: C r is the annual heat loss cost of the steam pipe network, RMB; C s is the annual condensate loss cost of the steam pipe network, RMB; h l is the corresponding steam enthalpy value, KJ / kg; h s is the corresponding saturated steam enthalpy, KJ / kg; M l is the condensation water loss in the pipe network, KW; Q l is the heat loss of the pipe network, KW.

[0020] Furthermore, the pipeline life cycle model uses the P1-P2 method to calculate the total life cycle cost of the steam pipeline network. The calculation equation is as follows:

[0021] Z=P1C r +P2C n

[0022]

[0023] minZ=P1C r +P2C n

[0024] Where: P1 is the present value factor, which takes into account the impact of interest rates and inflation on the future life cycle heat loss cost; P2 is the additional investment coefficient, which is the ratio of the life cycle expenditure generated by the additional investment to the initial investment. The insulation layer does not consider maintenance and transfer price, and its value is 1; d is the interest rate; i is the inflation rate; M s is the ratio of maintenance cost to initial cost; R Fis the ratio of resale price to initial cost; minZ represents the objective function of the life cycle cost of the steam pipeline network.

[0025] Furthermore, the insulation layer optimization module insulation layer calculation optimization process is as follows:

[0026] S1 obtains the inlet data measured by the target pipeline sensor and other target pipeline design parameters as input values ​​for the calculation module.

[0027] S2 sets the maximum iteration thickness of the i-th insulation layer to δ imax , set the initial iterative thickness δ of the i-th insulation layer i,0 =0.

[0028] S3 loads the input values ​​and calculates the momentum, energy, and continuity equations based on the steam thermodynamic-hydraulic coupling model to obtain the pipeline outlet pressure P2 and outlet temperature T2.

[0029] S4 calculates the pipeline outlet enthalpy value h2 based on the pipeline outlet pressure P2 and outlet temperature T2.

[0030] S5 Calculate the initial investment cost C of the pipeline based on the pipeline life cycle model n , pipeline operating cost C r , the total investment cost of the pipeline C t .

[0031] S6 determines the thickness δ of the i-th insulation layer i Is it greater than setting the maximum iteration thickness of the i-th insulation layer to δ? imax If it is less than, then the thickness of the i-th insulation layer δ i After adding 1mm, return to S3.

[0032] S7 determines the thickness of the insulation layer δ after the i-th iteration. i,i Total investment cost C t Is it the minimum? If not, set the maximum iteration thickness of the i-th insulation layer to δ imax After adding 10mm, return to S2.

[0033] S7 obtains the optimal insulation thickness δ of the i-th layer i , and the initial investment cost C of the pipeline under the insulation thickness n , pipeline operating cost C r , the total investment cost of the pipeline C t , output the result. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a steam pipe network insulation layer optimization calculation method provided by the present invention;

[0035] Figure 2The present invention provides a flow chart of a steam pipe network insulation layer optimization calculation method.

[0036] Figure 3 A comparison chart of calculation results of a steam thermal-hydraulic coupling model and field results for a steam pipe network insulation layer optimization calculation method provided by the present invention;

[0037] Figure 4 The present invention provides a diagram of the optimal insulation thickness of different insulation material combinations for a steam pipe network insulation layer optimization calculation method;

[0038] Figure 5 The present invention provides a minimum investment cost diagram of different insulation material combinations for an optimization calculation method of a steam pipe network insulation layer; DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, ordinary people in this field can make the following inventions without creative work.

[0040] like Figure 1 As shown, this method includes: a parameter acquisition module, a pipeline operation calculation module, and an insulation layer optimization module. The parameter acquisition module measures parameters by installing sensors at the starting end of the target pipeline, and combines these with relevant design parameters of the target pipeline as input values ​​for the optimization calculation method. The pipeline operation calculation module performs thermal-hydraulic coupling calculations on these input values ​​to obtain pipeline operation parameters, which provide a basis for setting the insulation layer. The insulation layer optimization module calculates parameters based on the steam pipeline life cycle model and iterates the insulation layer thickness to calculate the optimal insulation layer thickness and the total pipeline investment cost for this thickness.

[0041] like Figure 1 As shown, the parameter acquisition module includes sensors to measure pipeline inlet parameters and pipeline design parameters. Its main purpose is to collect the input values ​​required by the method as input values ​​of the pipeline operation calculation module.

[0042] like Figure 1 As shown, the core model of the pipeline operation calculation module is the steam thermodynamic-hydraulic coupling model, which consists of the continuity equation, the energy equation, and the momentum equation. The target pipeline operation parameters are calculated by combining the three equations to obtain the target pipeline outlet enthalpy value.

[0043] like Figure 1As shown, the core of the insulation layer optimization module is to calculate the initial investment cost and pipeline operating cost of the pipeline. Through the output target pipeline outlet enthalpy value, the total cost of the steam pipeline life cycle is calculated based on the P1-P2 method, so as to find the optimal insulation structure of the pipeline.

[0044] like Figure 2 As shown, the specific operation process of the steam pipe network insulation layer optimization calculation method is as follows:

[0045] S1 collects the target pipeline operating parameters of the steam network, including the operating parameters of pressure and temperature that change with the transportation distance, as the calculation result control group of the pipeline operation calculation module.

[0046] like Figure 3 As shown in the figure, the calculation results of the pipeline operation calculation module show that the error between the calculated and actual operating parameters is 0.309%, the error in the calculated enthalpy value is 0.1114%, and the error in the simulated heat loss value is 4.6%. Therefore, based on these results, it can be concluded that the results of the pipeline operation calculation module for calculating pipeline operating parameters are reliable.

[0047] S2 This embodiment takes the double-layer insulation structure of the buried pipeline, i.e., the inner and outer layers of the laying material as an example, and selects aerogel, glass wool, and aluminum silicate as the insulation materials. The calculation formula of the aerogel thermal conductivity is as follows:

[0048] λ1=0.018+2e-8T 2 +5e-5T

[0049] The calculation formula of thermal conductivity of glass wool is as follows:

[0050] λ2=0.046+0.00017(T-70)

[0051] The calculation formula of thermal conductivity of aluminum silicate is as follows:

[0052] λ3=0.044+0.0002(T m -70)

[0053] Where λ is the thermal conductivity of the material, W / (m·K); T is the material temperature, K.

[0054] The main heat transfer processes from steam in the steam pipe to the outside are as follows: 1) heat convection from the flowing steam to the inner wall of the pipe; 2) heat conduction from the pipe and the insulation layer; 3) heat conduction from the insulation layer to the soil. Therefore, the heat transfer coefficient K can be expressed as

[0055]

[0056] Where h mis the convective heat transfer coefficient of the flowing steam to the inner wall of the pipe, K is the heat transfer coefficient, W / (m·K), r1 is the inner diameter of the pipe, mm; r2 is the inner diameter of the inner insulation layer, mm; r3 is the outer diameter of the inner insulation layer, mm; r4 is the outer diameter of the outer insulation layer, mm; λ1 is the thermal conductivity of the inner insulation material, which is the thermal conductivity of aerogel in this case, W / (m·K); λ2 is the thermal conductivity of the outer insulation material, which is the thermal conductivity of glass wool in this case, W / (m·K); Rg is the ambient thermal resistance, K / W, which is the thermal resistance of the soil in this case.

[0057] S3 sets the initial iterative thickness δ of the inner insulation layer 1，0 , maximum iteration thickness δ 1，max ; Set the initial iterative thickness of the outer insulation layer δ 2，0 , set the maximum iterative thickness of the outer insulation layer δ 2，max Based on Matlab, the insulation layer optimization module is built for iterative calculation, and the initial investment cost and operating cost of the pipeline are iteratively calculated to obtain the total investment cost of the pipeline.

[0058] Find the minimum total investment cost of the pipeline, at which point the insulation structure is the best insulation structure. Under the conditions set in this embodiment, when the inlet temperature is 473K and the inlet flow rate is 100t / h, aerogel, aluminum silicate, and glass wool are combined to form a double-layer insulation structure. The optimal insulation thickness of the pipeline and the minimum total investment cost are as follows: Figure 3 and Figure 4 shown.

[0059] S4 ends the optimization calculation of the thermal insulation layer, records the optimal thermal insulation layer structure under the working condition, adjusts the thermal insulation material and inlet working condition, and performs the next optimization calculation.

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A steam pipe network pipe insulation layer optimization calculation method, characterized in that: It includes parameter acquisition module, pipeline operation calculation module, and insulation layer optimization module. The parameter acquisition module is configured to measure pipeline inlet parameters based on sensors provided at the starting end of the target pipeline, and use the measured parameters and relevant design parameters of the target pipeline as input values ​​for the optimization calculation method. The pipeline operation calculation module is configured to calculate the target pipeline operation parameters, perform a thermodynamic-hydraulic coupling calculation based on the input values ​​in combination with the relevant design parameters of the target pipeline, obtain the pipeline operation parameters, and provide a basis for setting the insulation layer. The insulation layer optimization module is configured to optimize the insulation layer of the target pipeline, and perform an insulation layer optimization calculation based on the steam network life cycle model, iteratively calculate the insulation layer thickness, and use the operating parameters obtained from the steam thermodynamic-hydraulic coupling calculation model to perform the insulation layer optimization calculation.

2. The parameter acquisition module according to claim 1, characterized in that Pressure, temperature and flow sensors are installed at the inlet of the target pipeline to measure the pressure, temperature and flow at the inlet of the target pipeline and obtain the operating parameters of the target pipeline.

3. The pipeline operation calculation module according to claim 1, characterized in that The measured parameters in claim 2 are used as input values, and the relevant design parameters of the target pipeline, including the pipeline inclination and pipeline diameter, are incorporated into the calculation process.

4. The thermal insulation layer optimization module according to claim 1, characterized in that The measured parameters in claim 2 are used as input values, and the relevant design parameters of the target pipeline, including pipeline length, pipeline operating years, and pipeline annual operating hours, are incorporated into the calculation process.

5. The steam thermodynamic-hydraulic coupling model according to claim 1, characterized in that Taking into account the influence of pipeline condensate, integrating energy, momentum, and continuity equations, and considering the thermal and hydraulic effects of the pipeline network on pipeline temperature and pressure, it more accurately reflects the pipeline operating conditions than traditional single hydraulic or thermal models.

6. The steam network life cycle model according to claim 1, characterized in that The initial investment cost and pipeline operating cost of the target pipeline are considered, and the total life cycle cost of the steam pipeline network is calculated using the P1-P2 method.

7. The thermal insulation layer optimization module according to claim 4, characterized in that The heat transfer coefficient of the insulation layer of different materials and the heat transfer coefficient of the soil are taken into consideration to calculate the comprehensive heat transfer coefficient of the pipeline.

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