A variable operating condition operation simulation method and system for energy hub

Abstract

The present invention discloses a method and system for simulating the variable operating condition operation of an energy hub, comprising: obtaining the electricity load within a simulation period; determining the power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler based on the electricity load; bringing the electricity load, power generation efficiency conversion coefficient, and heating efficiency conversion coefficient into a pre-constructed energy conversion equation to simulate the variable operating condition operation of the energy hub within the simulation period; the energy hub comprises: a gas turbine and a waste heat boiler. When simulating the energy hub, the present invention changes the energy conversion coefficient with the operating condition, overcoming the problem that the commonly used energy hub model can only reflect the output characteristics of the energy station under the rated working state, and can reflect the actual performance of the energy hub under the operating state.

Description

Technical Field

[0001] The present invention relates to the field of energy hub operating condition simulation, and in particular to a method and system for simulating the variable operating condition operation of an energy hub. Background Art

[0002] The concept of energy hubs plays a key role in the study of multi-energy systems and the energy internet. Current research on multi-energy systems and the energy internet based on energy hubs focuses on two aspects: first, the optimal configuration of energy hubs; second, the optimal operation of energy hubs. The key to the optimal configuration of energy hubs is what equipment should be used in the energy hub and what capacity of equipment should be used to achieve the goal of both meeting energy demand and minimizing costs. Existing research has discussed the configuration of energy hubs in detail for different types of energy users (such as schools, office buildings, hotels, etc.) and usage scenarios. The optimal operation of energy hubs mainly involves the selection of optimization objectives. Based on different optimization objectives, researchers have proposed different evaluation systems to evaluate the operating status of energy hubs.

[0003] However, existing models still have limitations. Existing energy hub models consider equipment operation based on steady-state models, and the energy conversion efficiency of equipment is mostly static. This modeling approach is feasible and reliable for designing the configuration and optimal operating conditions of multi-energy systems, but it cannot simulate multi-energy systems under varying operating conditions. Summary of the Invention

[0004] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a variable operating condition operation simulation method for an energy hub, comprising:

[0005] Obtain the power load during the simulation period;

[0006] Determining a power generation efficiency conversion coefficient of the gas turbine and a heating efficiency conversion coefficient of the waste heat boiler based on the power load;

[0007] The power load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient are introduced into the pre-built energy conversion equation to simulate the variable operating conditions of the energy hub within the simulation period;

[0008] The energy hub includes: a gas turbine and a waste heat boiler.

[0009] Preferably, the determining of the power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler based on the power load includes:

[0010] Based on the power load and a pre-built gas turbine model, obtaining a power generation curve and an exhaust gas temperature curve under variable operating conditions;

[0011] Fitting the power generation efficiency curve to determine constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation;

[0012] Determining a power generation efficiency conversion coefficient of the gas turbine based on a power generation efficiency conversion equation for determining constant parameter values ​​of the gas turbine;

[0013] Based on the exhaust gas temperature curve and a pre-built waste heat boiler model, obtaining variable operating parameters of the waste heat boiler;

[0014] Determining constant parameter values ​​of the waste heat boiler in a heating efficiency conversion equation based on the variable operating condition parameters of the waste heat boiler;

[0015] Based on a heating efficiency conversion equation for determining constant parameter values ​​of the waste heat boiler, a heating efficiency conversion coefficient of the waste heat boiler is determined.

[0016] Preferably, obtaining the power generation curve and the exhaust gas temperature curve under variable operating conditions based on the power load and the pre-built gas turbine model includes:

[0017] setting an initial operating condition for the gas turbine model based on the variable operating condition characteristics of each part of the gas turbine;

[0018] The flue gas flow rate is adjusted based on the power load and the shaft power balance condition in the gas turbine model, and the variable operating conditions of the gas turbine intermediate compressor, combustion chamber and turbine are continuously iterated to solve. When the power generation power of the gas turbine matches the power load, the iterative calculation is terminated to obtain the power generation efficiency curve and the gas turbine exhaust temperature curve under the variable operating conditions.

[0019] Preferably, the construction of the gas turbine model includes:

[0020] Based on the variable operating characteristics of the gas turbine, the compressor, combustion chamber and turbine in the gas turbine are respectively constructed, and the corresponding compressor sub-model, combustion chamber sub-model and turbine sub-model are constructed;

[0021] Constructing a gas turbine model based on the compressor sub-model, the combustion chamber sub-model and the turbine sub-model;

[0022] The shaft power balance condition is constructed for the gas turbine model based on the working principle of the gas turbine.

[0023] Preferably, obtaining the variable operating parameters of the waste heat boiler based on the exhaust gas temperature curve and a pre-built waste heat boiler model includes:

[0024] Taking the exhaust gas temperature curve of the gas turbine under rated operating conditions as the design operating conditions of the waste heat boiler model, and obtaining the waste heat boiler parameters under the design operating conditions;

[0025] Calculating the variable operating condition parameters of the waste heat boiler based on the waste heat boiler parameters under the design operating condition and the heat exchange equations in the waste heat boiler model;

[0026] The variable operating parameters of the waste heat boiler include superheated steam temperature and superheated steam flow rate.

[0027] Preferably, the construction of the waste heat boiler model includes:

[0028] Construct heat transfer equations for the economizer, evaporator and superheater in the waste heat boiler respectively;

[0029] Construct constraints for each heat transfer equation based on the heat transfer process;

[0030] A waste heat boiler model is constructed based on the heat exchange equations and the constraints.

[0031] Preferably, the energy conversion equation is as shown below:

[0032]

[0033] Where: L e : Power load; L h : Heating supply of energy hub; c ge : Power generation efficiency conversion coefficient; c gh : Heating efficiency conversion coefficient; P g : The heat released by the complete combustion of natural gas input per unit time.

[0034] Preferably, the power generation efficiency conversion equation is as shown below:

[0035]

[0036] Where: c ge : Power generation efficiency conversion coefficient; θ1: The first constant parameter of the gas turbine; θ2: The second constant parameter of the gas turbine; θ3: The third constant parameter of the gas turbine; N e,0 : Rated power generation of the gas turbine.

[0037] Preferably, the heating efficiency conversion equation is as shown below:

[0038]

[0039] Where: c gh : Heating efficiency conversion coefficient; β1: The first constant parameter of the waste heat boiler; β2: The second constant parameter of the waste heat boiler; β3: The third constant parameter of the waste heat boiler; β4: The fourth constant parameter of the waste heat boiler; N e,0 : Rated power generation of the gas turbine.

[0040] Based on the same inventive concept, the present invention also provides a variable operating condition operation simulation system for an energy hub, comprising:

[0041] An acquisition module is used to obtain the power load during the simulation period;

[0042] A calculation module, for determining a power generation efficiency conversion coefficient of the gas turbine and a heating efficiency conversion coefficient of the waste heat boiler based on the power load;

[0043] A simulation module, configured to introduce the electricity load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient into a pre-built energy conversion equation to simulate the variable operating conditions of the energy hub within a simulation period;

[0044] Among them, the energy hub includes: gas turbines and waste heat boilers.

[0045] Preferably, the calculation module includes:

[0046] A gas turbine calculation unit, configured to obtain a power generation curve and an exhaust gas temperature curve under variable operating conditions based on the power load and a pre-built gas turbine model;

[0047] a gas turbine constant parameter determination unit, configured to fit the power generation efficiency curve and determine constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation;

[0048] a power generation efficiency conversion coefficient calculation unit, configured to determine a power generation efficiency conversion coefficient of the gas turbine based on a power generation efficiency conversion equation for determining constant parameter values ​​of the gas turbine;

[0049] A waste heat boiler calculation unit, configured to obtain variable operating parameters of the waste heat boiler based on the exhaust gas temperature curve and a pre-built waste heat boiler model;

[0050] A waste heat boiler constant parameter determination unit, configured to determine a constant parameter value of the waste heat boiler in a heating efficiency conversion equation based on a variable operating condition parameter of the waste heat boiler;

[0051] The heating efficiency conversion coefficient calculation unit is used to determine the heating efficiency conversion coefficient of the waste heat boiler based on a heating efficiency conversion equation for determining a constant parameter value of the waste heat boiler.

[0052] Preferably, the system further comprises: a construction module for constructing an energy conversion equation;

[0053] The energy conversion equation is shown below:

[0054]

[0055] Where: L e: Power load; L h : Heating supply of energy hub; c ge : Power generation efficiency conversion coefficient; c gh : Heating efficiency conversion coefficient; P g : The heat released by the complete combustion of natural gas input per unit time.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The technical solution provided by the present invention obtains the electricity load within a simulation cycle; determines the power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler based on the electricity load; and introduces the electricity load, power generation efficiency conversion coefficient, and heating efficiency conversion coefficient into a pre-constructed energy conversion equation to simulate the variable operating conditions of the energy hub within the simulation cycle; the energy hub includes: a gas turbine and a waste heat boiler. During the simulation cycle, the operating conditions of the energy hub model change with changes in the electricity load. Under variable operating conditions, the power generation efficiency conversion coefficient and the heating efficiency conversion coefficient in the energy conversion equation also change. Therefore, the limitations of existing energy hub models are overcome and variable operating condition simulation of the energy hub model can be performed.

[0058] The power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler in the energy hub model constructed by the present invention change with the operating conditions, overcoming the problem that the commonly used energy hub model can only reflect the output characteristics of the energy station under the rated working state. It can provide the output characteristics of the energy hub during operation and can also be used to guide the operation optimization of the energy network interconnected by multiple energy hubs. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the compressor characteristic curve of the present invention;

[0060] Figure 2 The present invention is a flow chart of the calculation of variable operating conditions of a gas turbine;

[0061] Figure 3 Schematic diagram of power generation efficiency and fuel consumption of the gas turbine under variable operating conditions of the present invention;

[0062] Figure 4 Schematic diagram of exhaust gas temperature and exhaust gas pressure of a gas turbine under variable operating conditions of the present invention;

[0063] Figure 5 Schematic diagram of the waste heat boiler of the present invention;

[0064] Figure 6 This is a heat exchange flow chart of the waste heat boiler of the present invention;

[0065] Figure 7A schematic diagram of a general model of an energy hub of the present invention;

[0066] Figure 8 This is a schematic diagram of the cogeneration energy hub of the present invention;

[0067] Figure 9 This is a schematic diagram of the distribution of power generation and heating power of the energy hub throughout the day of the present invention;

[0068] Figure 10 This is a schematic diagram of the distribution of power generation efficiency and heating efficiency of the energy hub throughout the day of the present invention;

[0069] Figure 11 This is a flow chart of the variable operating condition operation simulation method of the energy hub of the present invention. DETAILED DESCRIPTION

[0070] In order to better understand the present invention, the present invention is further described below with reference to the accompanying drawings and examples.

[0071] Example 1

[0072] The present invention relates to an energy hub comprising a gas turbine and a waste heat boiler. The variable operating characteristics of the gas turbine and waste heat boiler are studied as follows:

[0073] 1. Gas turbine modeling

[0074] The gas turbine is a very complex aerodynamic thermodynamic system. When building a gas turbine model using a modular modeling approach, some assumptions are inevitably made. These assumptions include:

[0075] 1) The airflow in the gas turbine is one-dimensional along the axial direction of the gas turbine, and it is assumed that the gas parameters on the same cross section of the gas turbine are uniform and are uniformly represented by the total parameters of the cross section;

[0076] 2) Ignore the viscosity and inertial forces of the gas in the gas dynamics equation;

[0077] 3) Ignore the effects of combustion delay in gas turbines, thermal inertia and component channel volume dynamics;

[0078] 4) Assume that the thermodynamic and kinetic equations of gases in the rotating parts of the gas turbine are all one-dimensional and steady-state equations;

[0079] 5) The "air standard assumption" is often used to simplify the gas dynamic cycle, assuming that the working fluid has the same thermodynamic properties as air.

[0080] 1.1 Thermal cycle design

[0081] Due to confidentiality concerns regarding actual gas turbine design information and technical details, the various parameters of existing gas turbines are unavailable. Therefore, this paper first performed thermodynamic cycle calculations on a 30MW single-shaft gas turbine. The primary objective of this thermodynamic cycle calculation is to determine the basic characteristics of the 30MW gas turbine under design conditions, including flow rate, specific power, efficiency, and fuel consumption, as well as performance parameters at various characteristic interfaces. The selected parameters for the thermodynamic cycle calculation are shown in Table 1.

[0082] Table 1 Selected parameters in the thermal calculation process

[0083]

[0084]

[0085] According to the parameters selected in Table 1, the basic characteristics of the 30MW gas turbine are calculated and shown in Table 2.

[0086] Table 2 Performance parameters of 30MW gas turbine

[0087]

[0088] By comparing the reported parameters with those of actual gas turbines, it is found that the magnitude of the parameters of the 30MW-class gas turbine designed in the present invention is basically consistent with that of existing gas turbines of similar levels, proving that the thermodynamic cycle calculation is reliable as the basis for subsequent modeling.

[0089] A gas turbine consists of three components: the compressor, the combustion chamber, and the turbine. The variable operating conditions of the gas turbine are related to all three components, so these three components are modeled separately.

[0090] 1.2 Compressor modeling

[0091] The variable operating characteristics of a compressor can be described using a compressor characteristic curve. In the self-modeling region, the principle of similarity can be applied without requiring the Reynolds number to be equal. Therefore, the relationship between the compressor's pressure ratio and efficiency and similarity parameters can be constructed as the compressor characteristic curve. The similarity parameters here are the axial and circumferential Mach numbers. These two parameters are not always convenient to use, so parameters proportional to these similarity parameters—i.e., similar flow rate and similar speed—are used when plotting the characteristic curve.

[0092] In addition, when drawing the characteristic curve, the reduced parameter is used, that is, the ratio of the actual parameter to the rated operating parameter. In this invention, the subscript "0" represents the rated operating parameter, and the superscript "*" represents the reduced parameter. In summary, the characteristic curve of the compressor can be expressed as a functional relationship:

[0093]

[0094] Where:

[0095]

[0096]

[0097]

[0098] The proper selection of the parameters in the formula requires a lot of engineering experience. For a single-shaft gas turbine, the following parameters are selected:

[0099] m=1.06, p=0.36, c4=0.3 (5)

[0100] Where: is the reduced pressure ratio of the compressor, is the reduced efficiency of the compressor, is the compressor equivalent speed, is the equivalent similar flow rate of the compressor, m, p, c4 are empirical parameters.

[0101] From the above, we can get the characteristic curve of the compressor, such as Figure 1 As shown in the characteristic curve, each iso-similar speed line reaches a maximum pressure ratio as the similar flow rate decreases. This operating point is the critical control point of the compressor operation. If the compressor operating point is to the left of this point, there is a surge risk in the compressor operation. Therefore, the compressor should always operate to the right of the critical point.

[0102] 1.3 Combustion chamber modeling

[0103] The combustion chamber is a key component of a gas turbine. Fuel burns in the combustion chamber, producing high-temperature flue gas. While constant-pressure heating is ideal for heating the combustion chamber, pressure loss occurs in the actual cycle. This paper uses the pressure recovery coefficient of the combustion chamber to represent this pressure loss.

[0104] P b,out =σ b P b,in (6)

[0105] Where, P b,out Represents the combustion chamber outlet pressure, P b,in represents the combustion chamber inlet pressure, σ b Indicates the pressure recovery coefficient of the combustion chamber. The flue gas flow in the combustion chamber is equal to the sum of the air flow and the fuel flow in the compressor.

[0106] 1.4 Turbine Modeling

[0107] A turbine is a device that converts the thermal energy of high-temperature flue gas into mechanical energy. The operating characteristics of a turbine are described in a similar manner to those of a compressor. The variable operating characteristic curve of a turbine can also be obtained using polynomial fitting. Based on the principle of similarity, a single operating condition can also be determined using two parameters: the equivalent similar flow rate and the equivalent similar speed. Therefore, the expression for the turbine characteristic curve is shown in Equation (7). This invention assumes that the turbine does not reach a critical state under both the design operating condition and the variable operating condition. The relationship between the turbine flow rate and the expansion ratio can be expressed using the Flügel formula.

[0108]

[0109]

[0110] Where: is the reduced pressure ratio of the turbine, is the turbine's reduced efficiency, π t,0 is the rated pressure ratio of the turbine, is the reduced similar flow of the turbine, P t,in is the turbine inlet pressure, P t,in,0 is the rated inlet pressure of the turbine, is the reduced similar speed of the turbine, and α and t4 are empirical parameters.

[0111] 1.5 Calculation of Gas Turbine Variable Operating Conditions

[0112] Single-shaft gas turbines typically operate at a constant speed to directly drive a generator for power generation. Therefore, when the electrical load changes, the gas turbine output is controlled by adjusting the flue gas flow rate and fuel consumption to match the load. The shaft power of the gas turbine should meet the balance condition shown in the following formula:

[0113] W t -W c -W f -N e =0

[0114] Where W t is the output power of the turbine, W c is the power consumption of the compressor, W f is the mechanical loss of rotating parts, N e For the power generation.

[0115] Figure 2 The figure shows the process of calculating the variable operating condition of a gas turbine. First, the initial operating condition of the gas turbine is set to the design operating condition. Then, the user's electrical load is input. The flue gas flow rate is adjusted by judging whether the shaft power balance condition is met. The variable operating condition of each component of the gas turbine is solved iteratively. Finally, the power generation of the gas turbine is matched with the user's electrical load, thus completing the variable operating condition calculation. Figure 3 and Figure 4 As shown in the figure, as the operating point deviates further from the operating point, the unit efficiency becomes lower and lower, the fuel consumption also decreases with the decrease of output power, and the exhaust temperature and exhaust pressure increase with the decrease of output power.

[0116] 2. Waste Heat Boiler Modeling

[0117] The exhaust gas of a gas turbine is usually still at a high temperature of about 600℃, so the utilization of waste heat from the gas turbine can greatly improve the energy efficiency of the system. The waste heat boiler is the main equipment for waste heat recovery in the power cycle. The waste heat boiler can produce hot water or steam through waste heat recovery to supply other sections, realizing the cascade utilization of energy in the power cycle. The waste heat boiler involved in the present invention is a single-pressure superheated steam waste heat boiler, such as Figure 5 As shown, it includes three heat exchange units: economizer, evaporator and superheater.

[0118] In a single-pressure superheated steam waste heat boiler, the economizer and superheater are single-phase medium heat exchange units, while the evaporator is a phase change heat exchange unit. Therefore, the heat exchange flow diagram is as follows: Figure 6 shown.

[0119] 2.1 Basic equations of each unit

[0120] Each heat exchange unit of a single-pressure superheated steam waste heat boiler is subject to the constraints of the mass balance and energy balance equations during the heat exchange process, as shown in formula (9):

[0121]

[0122] Wherein, the subscript “in” represents the inlet parameters of the flue gas or water / steam, the subscript “out” represents the outlet parameters of the flue gas or water / steam, the subscript “g” represents the flue gas side, the subscript “w” represents the water / steam side, i represents the enthalpy value, κ represents the heat transfer coefficient, A represents the heat transfer area, and ΔT represents the heat transfer temperature difference.

[0123] The model used in the present invention includes the following assumptions:

[0124] The temperature difference of the evaporator unit varies greatly and the logarithmic mean temperature difference is used to calculate the heat transfer;

[0125] The temperature difference between the economizer unit and the superheater unit does not change much, so the arithmetic mean temperature difference is used to calculate the heat transfer;

[0126] The heat transfer coefficient is a constant;

[0127] Don’t remember sewage discharge.

[0128] In summary, according to Figure 6 The heat exchange process of each heat exchange unit shown in FIG. 1 is combined with the basic equation shown in formula (9) to obtain the heat exchange equation of each heat exchange unit.

[0129] Superheater:

[0130]

[0131] Evaporator:

[0132]

[0133] Economizer:

[0134]

[0135] In the above formula, Respectively represent the insulation coefficients of superheater, evaporator and economizer, which are considered as constants in this invention and are taken as 0.99; c p,g 、c p,s 、c p,w Represent the constant pressure specific heat capacity of flue gas, water vapor and water respectively; κ s , κ v , κ e Respectively represent the convection heat transfer coefficients of superheater, evaporator and economizer; A s 、A v 、A e Represent the heat exchange areas of the three heat exchange units respectively.

[0136] 2.2 Calculation of variable operating conditions of waste heat boiler

[0137] In the present invention, the exhaust gas temperature and flue gas flow rate of the gas turbine under rated operating conditions as described above are used as the design operating conditions of the waste heat boiler. The waste heat boiler parameters under the design operating conditions are shown in Table 3.

[0138] Table 3 Waste heat boiler design operating parameters

[0139]

[0140] To prevent the economizer unit from generating steam, the water at the economizer outlet should be unsaturated water with a certain amount of under-enthalpy. The temperature difference between the water temperature at the economizer outlet and the saturated water temperature at the corresponding pressure is called the approach point temperature difference, which is generally designed to be 10 to 20 degrees Celsius.

[0141] Based on the design operating parameters, the variable operating parameters of the HRSG can be calculated using Equations (10-12). The HRSG outlet steam parameters can be considered as functions with the gas turbine outlet flue gas flow rate and temperature as independent variables. Table 4 shows the parameters of superheated steam produced by the HRSG under different operating conditions.

[0142] Table 4 Variable operating parameters of waste heat boiler

[0143]

[0144] 3 Energy hub variable operating condition model

[0145] like Figure 7 The figure shows a general model of a multi-input multi-output energy hub. The energy conversion process of the multi-input multi-output energy hub can be implemented by a single device or by multiple devices. However, the specific structure inside the energy hub is not considered during modeling, and the energy hub is treated as a whole.

[0146] right Figure 7 The general model of the energy hub shown in FIG is modeled, and the energy conversion equation of the energy hub is shown in Equation (13).

[0147]

[0148] Where: vector L represents output energy, vector P represents input energy, and matrix C is called the energy hub coupling matrix. The input and output of various energy forms can be divided into two steps: energy distribution and energy transmission or conversion. Energy distribution refers to the allocation of various energy sources to different energy transmission or conversion devices in a certain proportion. Energy transmission or conversion refers to the conversion of energy input to the device through mechanical, chemical, or other means, with a certain conversion efficiency. Therefore, each element in matrix C represents the product of the distribution factor and efficiency factor for each energy source.

[0149] The schematic diagram of the combined heat and power energy hub consisting of a gas turbine and waste heat boiler is as follows: Figure 8 A combined heat and power (CHP) energy hub is a single-input, multi-output (SIO) energy hub that consumes natural gas from the upstream natural gas pipeline network and provides both electricity and heat to downstream energy users.

[0150] According to the mathematical model of the general energy hub model shown in formula (13), we can write Figure 8 The energy conversion equation for the combined heat and power energy hub is shown as:

[0151]

[0152] Where, L e is the user's electrical load, N e,0 is the rated power generation of the gas turbine; P g The heat released by the complete combustion of natural gas input per unit time.

[0153] The power generation efficiency conversion equation constructed in the present invention is used to calculate the power generation efficiency conversion coefficient c ge , as shown below:

[0154]

[0155] Where: cge : Power generation efficiency conversion coefficient; θ1: The first constant parameter of the gas turbine; θ2: The second constant parameter of the gas turbine; θ3: The third constant parameter of the gas turbine; N e,0 : Rated power generation of the gas turbine.

[0156] The present invention constructs a heating efficiency conversion equation for calculating the heating efficiency conversion coefficient, as shown in the following formula:

[0157]

[0158] Where: c gh : Heating efficiency conversion coefficient; β1: The first constant parameter of the waste heat boiler; β2: The second constant parameter of the waste heat boiler; β3: The third constant parameter of the waste heat boiler; β4: The fourth constant parameter of the waste heat boiler; N e,0 : Rated power generation of the gas turbine.

[0159] First of all, Figure 3 Fit the power generation efficiency curve in to determine the constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation:

[0160]

[0161] In this embodiment, after fitting, the value of the first constant parameter θ1 of the gas turbine is 14.183; the value of the second constant parameter θ2 of the gas turbine is 50.296; and the value of the third constant parameter θ3 of the gas turbine is 9.3945.

[0162] The cogeneration energy hub of the present invention adopts an operation mode of determining heat by electricity, that is, the heat output is determined according to the power supply load, which is equivalent to treating the generated heat as a by-product of power supply, and the heat absorbed by the working fluid water in the waste heat boiler is used to represent the heat supply of the cogeneration energy hub.

[0163] According to the variable operating characteristics of the waste heat boiler, the constant parameter values ​​of the waste heat boiler in the heating efficiency conversion equation are determined:

[0164]

[0165] In this embodiment, after fitting, the value of the first constant parameter β1 of the waste heat boiler is 37.921; the value of the second constant parameter β2 of the waste heat boiler is 125.81; the value of the third constant parameter β3 of the waste heat boiler is 109.55; and the value of the fourth constant parameter β4 of the waste heat boiler is 10.243.

[0166] The characteristics of the variable operating condition model of the energy hub constructed in this paper are mainly reflected in the change of the energy conversion coefficient in formula (14) with the operating condition. The energy conversion coefficient includes the power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler.

[0167] When the user's electricity load changes, the operating conditions of the energy hub model will also change. That is, the present invention considers the all-day changes in the electricity demand of energy users to examine the variable operating characteristics of the energy hub. Figure 9 The power generation capacity of the Central Energy Hub is determined by the electricity load of energy users, while the heating capacity is calculated using the hub's variable operating condition model. When the electricity load is low, the gas turbine generator set is less efficient, the exhaust temperature is higher, the exhaust flow is lower, and the available waste heat is greater. In this case, the waste heat boiler (HRSG) provides a higher heating capacity. As the electricity load approaches the rated power of the gas turbine generator set, the gas turbine generator set's power generation efficiency increases, the available waste heat decreases, and the HRSG's heating capacity decreases. Figure 10 This demonstrates the daily variations in power generation and heating efficiency within the energy hub. Gas turbine power generation efficiency is positively correlated with electrical load. However, the variable operating characteristics of the waste heat boiler's heating efficiency are much more complex than those of the gas turbine. The waste heat boiler's heating efficiency initially increases and then decreases with increasing gas turbine load, reaching its maximum value when the user's electrical load is approximately 60% of the gas turbine's rated power.

[0168] In summary, if Figure 11 As shown, the present invention provides a variable operating condition operation simulation method for an energy hub, comprising:

[0169] Step S1, obtaining the power load within the simulation period;

[0170] Step S2: determining a power generation efficiency conversion coefficient of the gas turbine and a heating efficiency conversion coefficient of the waste heat boiler based on the power load;

[0171] Step S3: Substitute the power load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient into a pre-constructed energy conversion equation to simulate the variable operating conditions of the energy hub within a simulation period;

[0172] The energy hub includes: a gas turbine and a waste heat boiler.

[0173] The present invention conducts equipment-level and system-level modeling for the cogeneration energy hub and constructs a variable operating condition model of the energy hub, including:

[0174] 1) If the device-level model based on physical modeling is directly used to model the energy system or energy network, it is quite complicated. Therefore, the device-level model is simplified and the variable operating characteristics of the equipment are described in the form of fitting equations.

[0175] 2) The energy hub operates in a heat-to-electricity mode, with the gas turbine's power generation matching the user's electricity load. The energy hub's power generation efficiency is positively correlated with the user's electricity load.

[0176] 3) The thermal power output by the waste heat boiler is a by-product of power generation in the energy hub. Its heating efficiency first increases and then decreases with the increase of user electricity load, and reaches the maximum value when the user electricity load is about 60% of the rated load of the gas turbine.

[0177] Example 2

[0178] Based on the same inventive concept, this embodiment also provides a variable operating condition operation simulation system for an energy hub, including:

[0179] An acquisition module is used to obtain the power load during the simulation period;

[0180] A calculation module, for determining a power generation efficiency conversion coefficient of the gas turbine and a heating efficiency conversion coefficient of the waste heat boiler based on the power load;

[0181] A simulation module, configured to introduce the electricity load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient into a pre-built energy conversion equation to simulate the variable operating conditions of the energy hub within a simulation period;

[0182] Among them, the energy hub includes: gas turbines and waste heat boilers.

[0183] In an embodiment, the calculation module includes:

[0184] A gas turbine calculation unit, configured to obtain a power generation curve and an exhaust gas temperature curve under variable operating conditions based on the power load and a pre-built gas turbine model;

[0185] a gas turbine constant parameter determination unit, configured to fit the power generation efficiency curve and determine constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation;

[0186] a power generation efficiency conversion coefficient calculation unit, configured to determine a power generation efficiency conversion coefficient of the gas turbine based on a power generation efficiency conversion equation for determining constant parameter values ​​of the gas turbine;

[0187] A waste heat boiler calculation unit, configured to obtain variable operating parameters of the waste heat boiler based on the exhaust gas temperature curve and a pre-built waste heat boiler model;

[0188] A waste heat boiler constant parameter determination unit, configured to determine a constant parameter value of the waste heat boiler in a heating efficiency conversion equation based on a variable operating condition parameter of the waste heat boiler;

[0189] The heating efficiency conversion coefficient calculation unit is used to determine the heating efficiency conversion coefficient of the waste heat boiler based on a heating efficiency conversion equation for determining a constant parameter value of the waste heat boiler.

[0190] In an embodiment, the system further comprises: a construction module for constructing an energy conversion equation;

[0191] The energy conversion equation is shown below:

[0192]

[0193] Where: L e : Power load; L h : Heating supply of energy hub; c ge : Power generation efficiency conversion coefficient; c gh : Heating efficiency conversion coefficient; P g : The heat released by the complete combustion of natural gas input per unit time.

[0194] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0195] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0196] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0197] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0198] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A variable operating condition operation simulation method for an energy hub, characterized in that: include: Obtain the power load during the simulation period; Determining a power generation efficiency conversion coefficient of a gas turbine and a heating efficiency conversion coefficient of a waste heat boiler based on the power load includes: Based on the power load and the pre-built gas turbine model, a power generation curve and an exhaust gas temperature curve under variable operating conditions are obtained, including: setting an initial operating condition for the gas turbine model based on the variable operating condition characteristics of each part of the gas turbine; adjusting the flue gas flow rate based on the power load and the shaft power balance condition in the gas turbine model, and continuously iteratively solving the variable operating conditions of the gas turbine's intermediate compressor, combustor, and turbine. When the power generation power of the gas turbine matches the power load, the iterative calculation is terminated to obtain a power generation efficiency curve and a gas turbine exhaust temperature curve under the variable operating conditions; Fitting the power generation efficiency curve to determine constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation; Determining a power generation efficiency conversion coefficient of the gas turbine based on a power generation efficiency conversion equation for determining constant parameter values ​​of the gas turbine; Based on the exhaust gas temperature curve and a pre-built waste heat boiler model, obtaining variable operating parameters of the waste heat boiler; Determining constant parameter values ​​of the waste heat boiler in a heating efficiency conversion equation based on the variable operating condition parameters of the waste heat boiler; Determining a heating efficiency conversion coefficient of the waste heat boiler based on a heating efficiency conversion equation for determining constant parameter values ​​of the waste heat boiler; The power load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient are introduced into the pre-built energy conversion equation to simulate the variable operating conditions of the energy hub within the simulation period; The energy hub includes: a gas turbine and a waste heat boiler.

2. The method according to claim 1, wherein The construction of the gas turbine model includes: Based on the variable operating characteristics of the gas turbine, the compressor, combustion chamber and turbine in the gas turbine are respectively constructed, and the corresponding compressor sub-model, combustion chamber sub-model and turbine sub-model are constructed; Constructing a gas turbine model based on the compressor sub-model, the combustion chamber sub-model and the turbine sub-model; The shaft power balance condition is constructed for the gas turbine model based on the working principle of the gas turbine.

3. The method according to claim 1, wherein The step of obtaining the variable operating parameters of the waste heat boiler based on the exhaust gas temperature curve and the pre-built waste heat boiler model includes: Taking the exhaust gas temperature curve of the gas turbine under rated operating conditions as the design operating conditions of the waste heat boiler model, and obtaining the waste heat boiler parameters under the design operating conditions; Calculating the variable operating condition parameters of the waste heat boiler based on the waste heat boiler parameters under the design operating condition and the heat exchange equations in the waste heat boiler model; The variable operating parameters of the waste heat boiler include superheated steam temperature and superheated steam flow rate.

4. The method according to claim 3, wherein The construction of the waste heat boiler model includes: Construct heat transfer equations for the economizer, evaporator and superheater in the waste heat boiler respectively; Construct constraints for each heat transfer equation based on the heat transfer process; A waste heat boiler model is constructed based on the heat exchange equations and the constraints.

5. The method according to claim 1, wherein The energy conversion equation is shown below: Where: L e : Power load; L h : Heating supply of energy hub; c ge : Power generation efficiency conversion coefficient; c gh : Heating efficiency conversion coefficient; P g : The heat released by the complete combustion of natural gas input per unit time.

6. The method according to claim 5, wherein The power generation efficiency conversion equation is shown below: Where: c ge : Power generation efficiency conversion coefficient; θ1: The first constant parameter of the gas turbine; θ2: The second constant parameter of the gas turbine; θ3: The third constant parameter of the gas turbine; N e,0 : Rated power generation of the gas turbine.

7. The method according to claim 5, wherein The heating efficiency conversion equation is shown below: Where: c gh : Heating efficiency conversion coefficient; β1: The first constant parameter of the waste heat boiler; β2: The second constant parameter of the waste heat boiler; β3: The third constant parameter of the waste heat boiler; β4: The fourth constant parameter of the waste heat boiler; N e,0 : Rated power generation of the gas turbine.

8. A variable operating condition operation simulation system for an energy hub, characterized in that: include: An acquisition module is used to obtain the power load during the simulation period; The calculation module is used to determine the power generation efficiency conversion coefficient of the gas turbine and the heating efficiency conversion coefficient of the waste heat boiler based on the power load, including: A gas turbine calculation unit, configured to obtain a power generation curve and an exhaust gas temperature curve under variable operating conditions based on the power load and a pre-built gas turbine model; a gas turbine constant parameter determination unit, configured to fit the power generation efficiency curve and determine constant parameter values ​​of the gas turbine in the power generation efficiency conversion equation; The power generation efficiency conversion coefficient calculation unit is used to determine the power generation efficiency conversion coefficient of the gas turbine based on the power generation efficiency conversion equation for determining the constant parameter value of the gas turbine, including: setting an initial operating condition for the gas turbine model based on the variable operating condition characteristics of each part of the gas turbine; adjusting the flue gas flow rate based on the power load and the shaft power balance condition in the gas turbine model, and continuously iteratively solving the variable operating conditions of the gas turbine's intermediate compressor, combustor, and turbine. When the power generation power of the gas turbine matches the power load, the iterative calculation is terminated to obtain a power generation efficiency curve and a gas turbine exhaust temperature curve under the variable operating conditions; A waste heat boiler calculation unit, configured to obtain variable operating parameters of the waste heat boiler based on the exhaust gas temperature curve and a pre-built waste heat boiler model; A waste heat boiler constant parameter determination unit, configured to determine a constant parameter value of the waste heat boiler in a heating efficiency conversion equation based on a variable operating condition parameter of the waste heat boiler; a heating efficiency conversion coefficient calculation unit, configured to determine a heating efficiency conversion coefficient of the waste heat boiler based on a heating efficiency conversion equation for determining a constant parameter value of the waste heat boiler; A simulation module, configured to introduce the electricity load, power generation efficiency conversion coefficient, and heat supply efficiency conversion coefficient into a pre-built energy conversion equation to simulate the variable operating conditions of the energy hub within a simulation period; Among them, the energy hub includes: gas turbines and waste heat boilers.

9. The system according to claim 8, wherein The system further comprises: a construction module for constructing an energy conversion equation; The energy conversion equation is shown below: Where: L e : Power load; L h : Heating supply of energy hub; c ge : Power generation efficiency conversion coefficient; c gh : Heating efficiency conversion coefficient; P g : The heat released by the complete combustion of natural gas input per unit time.

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