CN112307635B - Steam system energy expansion transformation optimization method, electronic equipment and storage medium - Google Patents
Steam system energy expansion transformation optimization method, electronic equipment and storage medium Download PDFInfo
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Abstract
The invention discloses a steam system energy expansion transformation optimization method, electronic equipment and a storage medium, wherein the method comprises the following steps: acquiring design variables of the existing steam system; based on design variables, constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam header pipe and a temperature and pressure reducer of the steam system to be modified of the existing steam system; establishing a capacity constraint condition; establishing a dosage constraint condition; establishing an objective function; and solving an objective function to obtain design variables of a newly added boiler, a newly added temperature and pressure reducer, a newly added turbine and a newly added steam header pipe of the steam system to be modified. On the premise of meeting the steam requirements of various production devices of an enterprise under different production loads, the invention fully utilizes the capability of the existing equipment to reduce newly-added equipment investment, and on the premise of ensuring the safety and stability of the steam system in the actual operation process, automatically obtains the modification scheme with the lowest comprehensive cost of the existing steam system through system optimization, thereby being beneficial to improving the economic competitiveness of the enterprise.
Description
Technical Field
The invention relates to the technical field related to a chemical process transformation optimization method, in particular to a steam system expansion transformation optimization method, electronic equipment and a storage medium.
Background
The steam system is used as one of the main energy sources required by petrochemical enterprises to provide power for driving equipment to operate and heat for heating materials for the production device. On the one hand, as market demands change and new processes of enterprises develop, production capacity of some devices is often required to be enlarged, or some new devices are added under existing steam systems. These factors lead to the structure and operating parameters of the steam system being in and out of the original design. If it cannot be judged in advance whether the existing steam system can adapt to different production loads of various devices of an enterprise or the steam requirements after the newly built expansion device is put on, the steam system is likely to become a bottleneck factor for limiting the effective release of the productivity of various devices of the enterprise. On the other hand, the steam usage is closely related to the operating load of the production plant. The operating load of existing units often needs to be adjusted due to changes in the market supply and demand of the feedstock and product, catalyst activity decay, changes in feedstock properties. After the production load of the device is adjusted, the required power and heat are changed, and the steam consumption or the steam yield is determined to be changed.
The existing steam system optimization method is focused on optimizing design of a newly built enterprise steam system structure such as configuration optimization of steam grade, boiler load and steam turbine capacity, or optimizing operation parameters of the existing steam system such as equipment operation load and pipeline flow of a boiler, a turbine and the like by assuming that the enterprise steam system structure is fixed so as to obtain lower operation cost. Different from the design optimization of a new enterprise steam system, the expansion transformation of the steam system needs to fully utilize the existing equipment capacity, thereby reducing the investment cost of the new equipment as much as possible. Unlike the existing steam system operating parameter optimization, steam system retrofit optimization, while also optimizing existing system operating parameters, also considers new equipment to meet the steam needs of process plant expansion or new plant.
Currently, many businesses tend to experience simply taking the sum of the maximum steam usage of all devices as a basis for selection of equipment and plumbing capacity. Because the steam consumption is the largest when most devices are started and stopped, the sum of the maximum steam flows of all the devices is taken as the capacity selection basis of the equipment and the pipelines, so that not only can the unnecessary investment cost be increased, but also the equipment and the pipelines can be caused to operate in a low-load zone when the devices are normally operated, the efficiency is lower, the energy loss is larger, and potential safety hazards can also exist. Therefore, global analysis and system optimization of steam system expansion reformulation are extremely important.
Disclosure of Invention
Based on the foregoing, it is necessary to provide a steam system expansion transformation optimization method, an electronic device and a storage medium, aiming at the technical problems that the prior art steam system expansion transformation lacks global analysis and system optimization.
The invention provides a steam system energy expansion transformation optimization method, which comprises the following steps:
obtaining design variables of a boiler, a temperature and pressure reducer, a turbine and a steam main pipe of the existing steam system;
based on the design variables, constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam manifold and a temperature and pressure reducer of the existing steam system;
based on the existing steam system, taking design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe as solving values, constructing a steam system to be modified, and constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam header pipe and the temperature and pressure reducer of the steam system to be modified;
establishing capacity constraint conditions, wherein the capacity constraint conditions are the maximum capacity of a boiler, a turbine and a temperature and pressure reducer existing in the existing steam system and the upper and lower limit constraint of the flow of a pipeline;
establishing a usage constraint condition, wherein the usage constraint condition is the usage and the yield of steam under the maximum operation load of each device using the output energy of the steam system and the usage and the yield of steam under the minimum operation load of each device;
Establishing an objective function for minimizing the sum of annual investment cost and operation cost of a newly added boiler, a newly added temperature and pressure reducer, a newly added turbine and a newly added steam header pipe;
and solving the objective function based on the mass balance formula, the energy balance formula, the capacity constraint condition and the consumption constraint condition to obtain design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe of the steam system to be modified.
Further, based on the design variables, constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam manifold and a temperature and pressure reducer thereof of the existing steam system, wherein the mass balance formula and the energy balance formula specifically comprise:
constructing a mass balance formula of steam flow of a steam manifold entering and exiting the existing steam system:
constructing an energy balance formula of steam flow of a steam manifold into and out of an existing steam system:
wherein F represents steam flow, h represents specific enthalpy of the stream, subscript b represents a b-th boiler of the existing steam system, subscript h represents a h-th steam header of the existing steam system, subscript t represents a t-th turbine of the existing steam system, subscript d represents a d-th temperature and pressure reducer of the existing steam system, subscript u represents a u-th device using output energy of the steam system, F r,loss Indicating the leakage loss of the (r) th steam header,for the h-stage steam usage of unit u, +.>Is a dressH stage steam yield of u, subscript b ′ The b ' th boiler is added, the subscript t ' is added, the t ' th turbine is added, the subscript d ' is added, the d ' th temperature and pressure reducer is added, and the subscript r ' is added, the r ' th steam header is added;
wherein is sigma r F b,r +∑ r′ F b,r′ +∑ t F b,t +∑ t′ F b,t′ ＝F b And F b (h STM -h BFW )＝η b F b,f h f ；
In the formula, h STM Indicating the specific enthalpy of steam produced by the boiler, h BFW Represents the specific enthalpy, eta of boiler feed water b Indicating the thermal efficiency of boiler b, F b,f Indicating the amount of fuel consumed by boiler b, h f Representing the low heating value of the fuel;
and constructing a mass balance formula of inlet and outlet steam of a turbine of the existing steam system: sigma (sigma) b F b,t +∑ b′ F b′,t +∑ r F r,t +∑ r′ F r′,t ＝∑ r F t,r +∑ r′ F t,r′ ；
Constructing an energy balance formula of inlet and outlet steam of a turbine of the existing steam system: sigma (sigma) b F b,t h b,t +∑ b′ F b′,t h b′,t +∑ r F r,t h r,t +∑ r′ F r′,t ＝∑ r h t,r F t,r +∑ r′ F t,r′ h t,r′ +W t Wherein W is t The work output by the turbine t to the outside is represented;
constructing a mass balance formula of a temperature and pressure reducer of the existing steam system: sigma (sigma) r F r,d +∑ r′ F r′,d +F d,w ＝∑ r F d,r +∑ r′ F d,r′ ；
Constructing an energy balance formula of a temperature and pressure reducer of the existing steam system: sigma (sigma) r F r,d h r +∑ r′ F r′,d h r′ +F w,d h w ＝h d (∑ r F d,r +∑ r′ F d,r′ ) Wherein F is w,d Represents the water supplementing quantity h of the temperature and pressure reducer d w Indicating the specific enthalpy of the boiler water, h d Indicating the specific enthalpy of the steam after depressurization and temperature reduction.
Further, the construction of the mass balance formula and the energy balance formula of each turbine, each stage of steam header pipe and the temperature and pressure reducing device thereof of the steam system to be modified specifically comprises the following steps:
Constructing a mass balance formula of steam flow of an newly added steam header pipe entering and exiting a steam system to be modified:
constructing an energy balance formula of steam flow of a newly added steam header pipe of an existing steam system:
wherein is sigma r F b′,r +∑ r′ F b′,r′ +∑ t F b′,t +∑ t′ F b′,t′ ＝F b′ And F b′ (h STM -h BFW )＝η b′ F b′,f h f ；
In eta b′ Indicating the thermal efficiency of the newly added boiler b', F b′,f Representing the amount of fuel consumed by the newly added boiler b', F r’,loss Indicating the leakage loss of the newly added r' steam header pipe;
constructing a mass balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified:
∑ b F b,t′ +∑ b′ F b′,t′ +∑ r F r,t′ +∑ r′ F r′,t′ ＝∑ r F t′,r +∑ r′ F t′,r′ ；
constructing an energy balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified:
∑ b F b,t′ h b,t′ +∑ b′ F b′,t′ h b′,t′ +∑ r F r,t′ h r,t′ +∑ r′ F r′,t′ ＝∑ r h t′,r F t′,r +∑ r′ F t′,r′ h t′,r′ +W t′ ，
in which W is t′ Representing the work output by the newly added turbine t' to the outside;
constructing a mass balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified: sigma (sigma) r F r,d′ +∑ r′ F r′,d′ +F d′,w ＝∑ r F d′,r +∑ r′ F d′,r′ ；
Constructing an energy balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified: sigma (sigma) r F r,d′ h r +∑ r′ F r′,d′ h r′ +F w,d′ h w ＝h d′ (∑ r F d′,r +∑ r′ F d′,r′ ) Wherein F is w,d′ Represents the water supplementing quantity h of the new temperature-increasing and reducing device d d′ Indicating the specific enthalpy of the steam after depressurization and temperature reduction.
Still further, the establishing the capability constraint condition specifically includes:
defining steam flow rate produced by each boilerWherein F is b For the steam flow of boiler b>Is the maximum capacity of the boiler b;
defining steam flow for each turbine Wherein F is b,t Representing the inlet flow of the t turbine connected with the b boiler, F b,t Represents the outlet air flow of the t turbine connected with the r steam header pipe,maximum allowable steam flow for the t turbine;
defining steam flow for each desuperheaterWherein F is d,r For the steam flow of the d-th desuperheater connected to the r-th steam header,/v>Maximum allowable steam flow for the d-th desuperheater;
defining steam flow between nodes p and q in a steam pipe network in an existing steam systemAnd->Wherein (1)>Representing the lowest safe flow between node p and node q in the existing steam pipe network,/>Representing the highest safe flow between node p and node q in the existing steam pipe network.
Still further, in the defining the existing steam system, the steam flow between the node p and the node q in the steam pipe network further includes:
the steam flow between nodes in the steam pipe network where no connection exists is set to 0.
Further, the establishing the usage constraint condition specifically includes:
limitingAnd->
Wherein,for the steam usage at maximum operating load of the ith unit connected to the h steam header,for the steam production of the (u) th device connected to the (h) th steam header at maximum operating load, is provided >For the steam quantity of the (u) th device connected to the (h) th steam header at minimum operating load, (-)>For the steam production at minimum operating load of the u-th device connected to the h-th steam header, x is a binary variable which can only take on a value of 0 or 1.
Further, the objective function of minimizing the sum of annual investment cost and operation cost of the newly added boiler, the newly added temperature and pressure reducer, the newly added turbine and the newly added steam header pipe is established, and specifically comprises the following steps:
establishing an objective function: min A (Sigma) b′ C b′ F b′ +∑ d′ C d′ F d′ +∑ t′ C t′ F t′ +∑ r′ C r′ F r′ )+τ(∑ b P f F b,f +∑ b′ P f F b′,f +P e (W-∑ t W t -∑ t′ W t′ ))；
Wherein A is the annual equipment investment costThe degree factor, C represents the equipment investment cost coefficient, tau represents the annual operating time, P f Indicating the unit price of fuel, W indicates the total electricity consumption of the existing device and the newly built device when all steam turbines are not started, and P e The electricity price is represented by the subscript b 'for the newly added b' boiler, the subscript t 'for the newly added t' turbine, the subscript d 'for the newly added d' desuperheater and the subscript r 'for the newly added r' steam header.
Still further, the annual factor
Where i represents the annual rate of funds and n represents the depreciated years of the device.
The invention provides a steam system energy expansion transformation optimization electronic device, which comprises:
At least one processor; the method comprises the steps of,
a memory communicatively coupled to at least one of the processors; wherein,
the memory stores instructions executable by at least one of the processors to enable the at least one processor to perform a steam system retrofit optimization method as previously described.
The present invention provides a storage medium storing computer instructions that, when executed by a computer, are operable to perform all the steps of a steam system expansion retrofitting optimization method as described above.
Aiming at the steam and power demand change brought by the expansion transformation of the existing device and the newly-built device of the petrochemical enterprise, the invention fully utilizes the capability of the existing equipment to reduce the investment of newly-added equipment on the premise of meeting the steam demand of each production device of the enterprise under different production loads, and automatically obtains the transformation scheme with the lowest comprehensive cost of the existing steam system through system optimization on the premise of ensuring the safety and stability of the actual operation process of the steam system, thereby being beneficial to improving the economic competitiveness of the enterprise.
Drawings
FIG. 1 is a flow chart of a steam system expansion improvement optimization method according to an embodiment of the present invention;
FIG. 2 is a schematic illustration of a steam system expansion improvement optimization method according to an embodiment of the present invention;
FIG. 3 is a block diagram of a steam system of a petrochemical enterprise;
fig. 4 is a schematic hardware structure diagram of a steam system energy expansion transformation optimization electronic device according to an embodiment of the invention.
Detailed Description
The invention will now be described in further detail with reference to the drawings and to specific examples.
Example 1
FIG. 1 is a flow chart of a steam system expansion improvement optimization method according to an embodiment of the present invention, including:
step S101, obtaining design variables of a boiler, a temperature and pressure reducer, a turbine and a steam header pipe of the existing steam system;
step S102, based on the design variables, constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam manifold and a temperature and pressure reducer thereof of the existing steam system;
step S103, on the basis of the existing steam system, constructing a steam system to be modified by taking design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe as solving values, and constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam header pipe and the temperature and pressure reducer of the steam system to be modified;
Step S104, establishing capacity constraint conditions, wherein the capacity constraint conditions are the maximum capacities of a boiler, a turbine and a temperature and pressure reducer existing in the existing steam system and the upper and lower limit constraints of the flow of a pipeline;
step S105, establishing a consumption constraint condition, wherein the consumption constraint condition is the consumption and the output of the steam under the maximum operation load of each device using the output energy of the steam system and the consumption and the output of the steam under the minimum operation load of each device;
step S106, establishing an objective function for minimizing the sum of annual investment cost and operation cost of the newly added boiler, the newly added temperature and pressure reducer, the newly added turbine and the newly added steam header pipe;
and step S107, solving the objective function based on the mass balance formula, the energy balance formula, the capacity constraint condition and the consumption constraint condition to obtain design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe of the steam system to be modified.
Specifically, in step S101, design variables of the existing steam system structure, including the number of boilers, the steam production pressure and the maximum steam production of each boiler, the steam manifold grade, the pressure and the temperature range of each grade steam manifold, the type, the number and the operation characteristics of turbines, the position and the design capacity of the temperature and pressure reducer, and the like, are collected. In petrochemical industry steam system, the boiler utilizes the chemical energy of fuel to heat water and produce steam, and the turbine is with the external acting of feeding high pressure steam drive for device power and low pressure steam, thereby the steam pipe is concentrated and to reduce the steam pipeline quantity of large-scale enterprise by a wide margin to simplify the pipeline arrangement, and the pressure reducer can be with high pressure high temperature steam decompression cooling in order to satisfy the demand of device, and chemical industry device utilizes heat and power that the steam provided to realize that the raw materials turn into product and material transport.
Then, step S102 and step S103 construct mass balance formulas and energy balance formulas of the existing steam system and each turbine of the steam system to be modified, each stage of steam manifold and the temperature and pressure reducing device thereof. Step S104 establishes the maximum capacity of the boiler, turbine, desuperheater and pressure reducer and the upper and lower limits of the pipeline flow existing in the existing steam system. Step S105 analyzes the steam and power requirements of each grade of the device under different production conditions, and determines the steam usage and yield under the maximum operation load and the steam usage and yield under the minimum operation load of each device. Finally, step S106 establishes an objective function for steam network flexibility improvement. The model aims at minimizing the sum of annual investment cost and operation cost of newly added boilers, temperature and pressure reducers, turbines and pipelines. Step S107, obtaining a steam system which can adapt to each production working condition by solving the objective function, and finishing transformation optimization. And setting the flow between connection nodes which do not exist in the existing pipe network to be zero to determine the existing pipe network connection structure. The optimization model considers all possible connections between the newly-added equipment and the existing equipment pipelines and between the newly-added equipment and other newly-added equipment, and through solving an objective function, if the connection flow between the two equipment in the solving result is zero, the connection between the two equipment is not present, and otherwise, the connection is present.
Aiming at the steam and power demand change brought by the expansion transformation of the existing device and the newly-built device of the petrochemical enterprise, the invention fully utilizes the capability of the existing equipment to reduce the investment of newly-added equipment on the premise of meeting the steam demand of each production device of the enterprise under different production loads, and automatically obtains the transformation scheme with the lowest comprehensive cost of the existing steam system through system optimization on the premise of ensuring the safety and stability of the actual operation process of the steam system, thereby being beneficial to improving the economic competitiveness of the enterprise.
Example two
FIG. 2 is a flow chart showing a steam system expansion improvement optimization method according to an embodiment of the present invention, including:
step S201, obtaining design variables of a boiler, a temperature and pressure reducer, a turbine and a steam header pipe of the existing steam system;
step S202, constructing a mass balance formula of steam flow of a steam manifold entering and exiting the existing steam system:
step S203, constructing an energy balance formula of steam flow into and out of a steam manifold of the existing steam system:
wherein F represents steam flow, h represents specific enthalpy of the material flow, and subscript b represents currentA b-th boiler with a steam system, the subscript r denotes a r-th steam header of the existing steam system, the subscript t denotes a t-th turbine of the existing steam system, the subscript d denotes a d-th temperature and pressure reducer of the existing steam system, the subscript u denotes a u-th device using output energy of the steam system, F r,loss Indicating the leakage loss of the (r) th steam header,for r-stage steam usage of unit u, +.>For r-stage steam production of unit u, subscript b 'represents the newly added b' th boiler, subscript t 'represents the newly added t' th turbine, subscript d 'represents the newly added d' th desuperheater and subscript r 'represents the newly added r' th steam header;
wherein is sigma r F b,r +∑ r′ F b,r′ +∑ t F b,t +∑ t′ F b,t′ ＝F b And F b (h STM -h BFW )＝η b F b,f h f ；
In the formula, h STM Indicating the specific enthalpy of steam produced by the boiler, h BFW Represents the specific enthalpy, eta of boiler feed water b Indicating the thermal efficiency of boiler b, F b,f Indicating the amount of fuel consumed by boiler b, h f Representing the low heating value of the fuel;
step S204, constructing a mass balance formula of inlet and outlet steam of a turbine of the existing steam system: sigma (sigma) b F b,t +∑ b′ F b′,t +∑ r F r,t +∑ r′ F r′,t ＝∑ r F t,r +∑ r′ F t,r′ ；
Step S205, constructing an energy balance formula of inlet and outlet steam of a turbine of the existing steam system: sigma (sigma) b F b,t h b,t +∑ b′ F b′,t h b′,t +∑ r F r,t h r,t +∑ r′ F r′,t ＝∑ r h t,r F t,r +∑ r′ F t,r′ h t,r′ +W t Wherein W is t The work output by the turbine t to the outside is represented;
step S206, constructing a mass balance formula of the temperature and pressure reducer of the existing steam system: sigma (sigma) r F r,d +∑ r′ F r′,d +F d,w ＝∑ r F d,r +∑ r′ F d,r′ ；
Step S207, constructing an energy balance formula of a temperature and pressure reducer of the existing steam system: sigma (sigma) r F r,d h r +∑ r′ F r′, d h r′ +F w,d h w ＝h d (∑ r F d,r +∑ r′ F d,r′ ) Wherein F is w,d Represents the water supplementing quantity h of the temperature and pressure reducer d w Indicating the specific enthalpy of the boiler water, h d Indicating the specific enthalpy of the steam after depressurization and temperature reduction.
Step S208, on the basis of the existing steam system, constructing a steam system to be modified by taking design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe as solving values, and constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam header pipe and the temperature and pressure reducer of the steam system to be modified;
Constructing a mass balance formula of steam flow of an newly added steam header pipe entering and exiting a steam system to be modified:
constructing an energy balance formula of steam flow of a newly added steam header pipe of an existing steam system:
wherein is sigma r F b′,r +∑ r′ F b′,r′ +∑ t F b′,t +∑ t′ F b′,t′ ＝F b′ And F b′ (h STM -h BFW )＝η b′ F b′,f h f ；
In eta b′ Indicating the thermal efficiency of the newly added boiler b', F b′,f Representing the amount of fuel consumed by the newly added boiler b', F r’,loss Indicating the leakage loss of the newly added r' steam header pipe;
constructing a mass balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified: sigma (sigma) b F b,t′ +∑ b′ F b′,t′ +∑ r F r,t′ +∑ r′ F r′,t′ ＝∑ r F t′,r +∑ r′ F t′,r′ ；
Constructing an energy balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified: sigma (sigma) b F b,t′ h b,t′ +∑ b′ F b′,t′ h b′,t′ +∑ r F r,t′ h r,t′ +∑ r′ F r′,t′ ＝∑ r h t′,r F t′,r +∑ r′ F t′,r′ h t′,r′ +W t′ Wherein W is t′ Representing the work output by the newly added turbine t' to the outside;
constructing a mass balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified: sigma (sigma) r F r,d′ +∑ r′ F r′,d′ +F d′,w ＝∑ r F d′,r +∑ r′ F d′,r′ ；
Constructing an energy balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified: sigma (sigma) r F r,d′ h r +∑ r′ F r′,d′ h r′ +F w,d′ h w ＝h d′ (∑ r F d′,r +∑ r′ F d′,r′ ) Wherein F is w,d′ Represents the water supplementing quantity h of the new temperature-increasing and reducing device d d′ Representing the steam ratio after decompression and temperature reductionEnthalpy of the heart.
Step S209, establishing capacity constraint conditions, wherein the capacity constraint conditions are the maximum capacities of a boiler, a turbine and a temperature and pressure reducer existing in the existing steam system and the upper and lower limit constraints of the flow of a pipeline;
the establishment of the capacity constraint condition specifically comprises the following steps:
Defining steam flow rate produced by each boilerWherein F is b For the steam flow of boiler b>Is the maximum capacity of the boiler b;
defining steam flow for each turbineWherein F is b,t And F b′,t Respectively represents the inlet steam flow of the t turbine connected with the existing b-th boiler and the newly added b' -th boiler, F r,t And F r′,t Respectively representing the outlet air flow of the t turbine connected with the existing r-th steam main pipe and the newly added r' -th steam main pipe,/the outlet air flow of the t turbine>Maximum allowable steam flow for the t turbine;
defining steam flow for each desuperheaterWherein F is d,r And F d,r′ The steam flow of the d-th temperature and pressure reducing device connected with the existing r-th steam main pipe and the newly added r' -th steam main pipe is thatMaximum allowable steam flow of the d-th desuperheater;
defining nodes p and nodes in a steam pipe network in an existing steam systemSteam flow between qAnd->Wherein (1)>Representing the lowest safe flow between node p and node q in the existing steam pipe network,/>Representing the highest safe flow between a node p and a node q in the existing steam pipe network;
in one embodiment, the defining the steam flow between the node p and the node q in the steam pipe network further includes:
The steam flow between nodes in the steam pipe network where no connection exists is set to 0.
Step S210, establishing a consumption constraint condition, wherein the consumption constraint condition is the consumption and the output of steam under the maximum operation load of each device using the output energy of the steam system and the consumption and the output of steam under the minimum operation load of each device;
the establishment of the consumption constraint condition specifically comprises the following steps:
limitingAnd->
Wherein,for the steam usage at maximum operating load of the (u) th device connected to the (r) th steam header,for the steam production of the (u) th device connected to the (r) th steam header at maximum operating load, is provided>For the steam quantity of the (u) th device connected to the (r) th steam header at minimum operating load, (-)>For the steam yield of the (u) th device connected with the (r) th steam header pipe under the minimum operating load, x is a binary variable which can only take on a value of 0 or 1;
step S211, establishing an objective function min A (Sigma) for minimizing the sum of annual investment cost and operation cost of the newly added boiler, the newly added temperature and pressure reducer, the newly added turbine and the newly added steam header pipe b′ C b′ F b′ +∑ d′ C d′ F d′ +∑ t′ C t′ F t′ +∑ r′ C r′ F r′ )+τ(∑ b P f F b,f +∑ b′ P f F b′,f +P e (W-∑ t W t -∑ t′ W t′ ))；
Wherein A is an annual factor of equipment investment cost, C is an equipment investment cost coefficient, τ is annual operation time, and P f Indicating the unit price of fuel, W indicates the total electricity consumption of the existing device and the newly built device when all steam turbines are not started, and P e The electricity price is represented by the subscript b 'for the newly added b' boiler, the subscript t 'for the newly added t' turbine, the subscript d 'for the newly added d' desuperheater and the subscript r 'for the newly added r' steam header. The method comprises the steps of carrying out a first treatment on the surface of the
In one embodiment, the annual factor
Wherein i represents annual rate of funds and n represents depreciated years of the device;
and step S212, solving the objective function based on the mass balance formula, the energy balance formula, the capacity constraint condition and the consumption constraint condition to obtain design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe of the steam system to be modified.
Specifically, the invention provides a reconstruction optimization method for improving the capacity of the existing steam system of a petrochemical enterprise, which fully utilizes the capacity of the existing equipment to reduce newly-added equipment investment on the premise of meeting the steam demand of a production device, considers the constraints of safety, stability, economy, equipment characteristics and the like in the actual operation process of the steam system, and simultaneously automatically obtains the expansion reconstruction optimization scheme of the steam system with the lowest cost through system optimization. The method is based on thermodynamic principles such as mass conservation, energy conservation and the like and a steam system super-structure model, and according to actual production data of enterprises, a scheme with the lowest cost is obtained by solving a steam system transformation optimization model.
Aiming at the newly increased steam power demand of petrochemical enterprises caused by newly built devices and device expansion, the invention can obtain the existing steam system modification scheme with the lowest newly increased equipment investment and operation cost, and fully considers the steam power demand change of the devices in the normal operation range.
The method comprises the following specific steps:
1. the design variables of the existing steam system structure are collected, and the design variables comprise basic data such as the number of boilers, the steam production pressure and the maximum steam production of each boiler, the grade of a steam main pipe, the pressure and the temperature range of the steam main pipe of each grade, the types, the number and the operation characteristics of turbines, the position and the design capacity of a temperature and pressure reducer and the like.
2. And constructing mass balance and energy balance of each turbine, each stage of steam header pipe and a temperature and pressure reducer of each turbine. The steam flow into and out of the existing and newly added steam header should satisfy mass and energy balances
Wherein F represents flow rate, kg/h; h represents the specific enthalpy of the material flow, kJ/kg; subscripts b, r, t, d and u represent respectively a boiler, a steam header, a turbine, a temperature and pressure reducer and a device; f (F) r,loss The leakage loss of the steam header pipe is shown as kg/h. Note that, unlike mass balance and energy balance of a general steam system optimization model, the h-stage steam usage (or production) of device u (or->) Decision variables that are not determined by the optimization model. Their values are related to the actual operating load of the device, and they are invariable constant values in the case of a certain device load.
The steam flow of the device is the steam flow necessary for the process under a certain production load, and the adjustable steam consumption such as the steam flow of the switchable device and the temperature and pressure reducer is not included. This is to avoid that there may be a temperature and pressure reducer between different levels of steam inside the device, resulting in uncertainty in the amount of steam used for each level.
Steam defining existing and newly added boiler production is supplied to each stage of steam pipe network and turbine
∑ r F b,r +∑ r′ F b,r′ +∑ t F b,t +∑ t′ F b,t′ ＝F b
Wherein the energy of the steam generated by the boiler is derived from fuel
F b (h STM -h BFW )＝η b F b,f h f
Wherein h is STM Represents the specific enthalpy, kJ/kg, of the steam produced by boiler b; h is a BFW Represents the specific enthalpy of boiler feed water, kJ/kg; η (eta) b Indicating the thermal efficiency of boiler b; f (F) b,f Representing the consumption of boiler bFuel amount, kg/h; h is a f Indicating the low heating value of the fuel.
The inlet and outlet steam limiting the existing and newly added turbines should satisfy mass balance and energy balance
∑ b F b,t +∑ b′ F b′,t +∑ r F r,t +∑ r′ F r′,t ＝∑ r F t,r +∑ r′ F t,r′
∑ b F b,t h b,t +∑ b′ F b′,t h b′,t +∑ r F r,t h r,t +∑ r′ F r′,t
＝∑ r h t,r F t,r +∑ r′ F t,r′ h t,r′ +W t
In which W is t The work output by the turbine t to the outside is shown as kJ/h.
The existing and newly added temperature and pressure reducers are limited to meet the conservation of mass and energy
∑ r F r,d +∑ r′ F r′,d +F d,w ＝∑ r F d,r +∑ r′ F d,r′
∑ r F r,d h r +∑ r′ F r′,d h r′ +F w,d h w ＝h d (∑ r F d,r +∑ r′ F d,r′ )
Wherein F is w,d The water supplementing amount of the temperature and pressure reducer d is expressed as kg/h; h is a w Indicating the specific enthalpy of boiler water, kJ/h; h is a d The specific enthalpy of the steam after depressurization and temperature reduction is shown as kJ/kg.
3. The maximum capacity of the boiler, the turbine and the temperature and pressure reducer and the upper and lower limit constraints of the pipeline flow existing in the existing steam system are established.
The steam production of the existing boiler should not exceed the maximum capacity
The newly added boiler has no capacity limitation.
The inlet steam flow and the outlet steam flow of the turbine are in the design range
The flow rate of the existing temperature and pressure reducing device should not exceed the maximum capacity
The maximum capacity of the new temperature and pressure reducer is determined by model optimization.
The flow rate of each pipe section is in a reasonable range
In the method, in the process of the invention,representing the lowest safe flow between a node p and a node q in the existing steam pipe network; />Representing the highest safe flow between node p and node q in the existing steam pipe network.
Setting connection traffic that is not actually present in the steam network to zero
(if a connection between nodes p and q does not exist)
5. Analyzing the steam and power demands of each grade of the device under different production conditions, and respectively determining the steam consumption under the maximum operation load of each deviceAnd yield->And steam usage at minimum operating load +. >And yield ofIn order for the steam network to have sufficient operating flexibility, it should be satisfied that
Where x is a binary variable that can only take on a value of 0 or 1.
6. And establishing an objective function for steam network flexibility transformation. The aim of the model is to minimize the sum of annual investment costs and operating costs of newly added boilers, desuperheaters, turbines and pipelines, i.e
min A(∑ b′ C b′ F b′ +∑ d′ C d′ F d′ +∑ t′ C t′ F t′ +∑ r′ C r′ F r′ )+τ(∑ b P f F b,f +∑ b′ P f F b′,f +P e (W-∑ t W t -∑ t′ W t′ ))；
Wherein A is an annual factor of equipment investment cost, and is considered on the basis of linear depreciationThe time value of the funds is considered; c represents the equipment investment cost coefficient, namely the equipment investment cost under the unit flow, in order to reduce the solving difficulty of the method and not lose the investment cost difference of different types of equipment, the equipment investment cost is assumed to be in direct proportion to the flow of the equipment investment cost, and the equipment investment cost can be obtained according to the ratio of the equipment investment cost of the same type to the flow of the equipment investment cost; τ represents annual run time, h/year; p (P) f Indicating fuel unit price, yuan/kg; w represents the total electricity consumption of the existing and newly-built devices when all steam turbines are not started, and kJ/h; p (P) e Representing electricity price, yuan/kJ; subscripts b ', d', t ', r' respectively represent a newly added boiler, a newly added temperature and pressure reducer, a newly added steam turbine and a newly added steam pipeline. Note that the investment cost of existing plants is not an objective function of the retrofit optimization due to the retrofit of existing steam pipe networks.
The calculation formula of the annual factor of the equipment investment cost is as follows
Where i represents the annual rate of funds and n represents the depreciated years of the device.
The method takes the sum of annual operation cost and annual equipment investment cost as an optimization target, and simultaneously considers the constraint of operation flexibility, so that a steam system transformation optimization scheme which takes both economy and operation flexibility into consideration can be obtained. In general, the larger the pipeline size and the capacity of the desuperheater and the steam turbine, the higher the flexibility of operation, and of course the equipment investment costs are accompanied by the higher water heave, so that a proper trade-off between equipment investment and steam pipe network flexibility is required. On the other hand, given that the investment costs for steam turbines at equal flows are generally much greater than those for the desuperheater, it would be advantageous to choose the desuperheater rather than the steam turbine if the investment of equipment alone were considered. However, the steam turbine can effectively recover the steam with higher pressure to the steam with lower pressure to replace the motor to apply work or directly generate electricity, so that the electric power is saved, and the operation cost of the steam system can be greatly reduced compared with a temperature and pressure reducer. Therefore, the method provided by the invention considers the equipment investment cost and the operation cost at the same time, takes the minimum sum of the annual equipment investment cost and the operation as the optimization target, and can obtain a scheme which meets the operation flexibility requirement and has better economic competitiveness. The equipment investment cost of the method is calculated by adopting a relative capacity method, so that the relative size of different equipment investments is fully considered, and the complexity of a model and the solving difficulty are reduced.
7. Solving the optimization model to automatically obtain a steam system which can adapt to each production working condition, and finishing transformation and optimization.
An example of a specific implementation of a modification and optimization method for improving the operation flexibility of a steam system of a petrochemical enterprise is described in detail below.
As shown in FIG. 3, the structure of a steam system of a petrochemical enterprise is shown by solid lines and added devices and apparatuses are shown by broken lines.
1. And collecting the structure and basic design data of the existing steam pipe network of the enterprise. In this example, there are 1 steam boiler, 2 back pressure turbines t1,3 grade steam manifolds HS, MS, LS,3 desuperheaters d1, d2, d3. The capabilities of the individual devices and pipes are shown in the table below.
2. And constructing mass balance and energy balance of each turbine, each stage of steam header pipe and a temperature and pressure reducer of each turbine. The steam flow into and out of each grade steam header should satisfy mass balance and energy balance
Wherein F represents flow rate, kg/h; h represents specific enthalpy, kJ/kg; subscripts b, r, t, d and u represent respectively a boiler, a steam header, a turbine, a temperature and pressure reducer and a device; fr, loss represents the steam header leakage loss, kg/h. Note that, unlike mass balance and energy balance of a general steam system optimization model, the r-stage steam usage (or production) of device u (or->) Decision variables that are not determined by the optimization model. Their values are related to the actual operating load of the device, and they are invariable constant values in the case of a certain device load.
Wherein, the steam system to be reformed comprises a new temperature-increasing and pressure-reducing device d4, a turbine t3 and a device u4.
The inlet and outlet steam of the turbine should satisfy the mass balance and the energy balance
∑ b F b,t +∑ b′ F b′,t +∑ r F r,t +∑ r′ F r′,t ＝∑ r F t,r +∑ r′ F t,r′
∑ b F b,t h b,t +∑ b′ F b′,t h b′,t +∑ r F r,t h r,t +∑ r′ F r′,t
＝∑ r h t,r F t,r +∑ r′ F t,r′ h t,r′ +W t
In which W is t The work output by the turbine to the outside is shown as kJ/h.
The temperature and pressure reducer should meet the mass balance and energy balance
∑ r F r,d +∑ r′ F r′,d +F d,w ＝∑ r F d,r +∑ r′ F d,r′
∑ r F r,d h r +∑ r′ F r′,d h r′ +F w,d h w ＝h d (∑ r F d,r +∑ r′ F d,r′ )
Wherein F is w,d The water supplementing amount of the temperature and pressure reducer d is expressed as kg/h; h is a w Represents the specific enthalpy of boiler water, kJ/kg; h is a d The specific enthalpy of the steam after depressurization, kJ/kg.
3. And establishing the maximum capacity constraint of the boiler, the turbine and the temperature and pressure reducer, and the maximum flow and minimum flow constraint of the pipeline. The steam yield of the boiler should not exceed the maximum capacity
∑ r F b,r +∑ r′ F b,r′ +∑ t F b,t +∑ t′ F b,t′ ≤180000
The inlet steam flow and the outlet steam flow of the turbine are in the design range
∑ b F b,t1 +∑ r F r,t1 +∑ r′ F r′,t1 ≤150000
∑ b F b,t2 +∑ r F r,t2 +∑ r′ F r′,t2 ≤60000
The flow rate of the temperature and pressure reducer should not exceed the maximum capacity
∑ r F d1,r +∑ r′ F d1,r′ ≤120000
∑ r F d2,r +∑ r′ F d2,r′ ≤100000
∑ r F d3,r +∑ r′ F d3,r′ ≤60000
The flow rate of each pipe section is within a reasonable range
F r1 ≤220000
F r2 ≤90000
F r3 ≤80000
4. The connection traffic that is not actually present in the existing steam network is set to zero. In this example, except for steamingF in the steam network with exactly-connected pipes b1,d1 ，F b1,t1 ，F r1,u1 ，F r1,d2 ，F r1,t2 ，F u2,r1 ，F d2,r2 ，F u1,r2 ，F r2,d3 ，F r2,u3 ，F r2,u4 ，F d3,r3 ，F t3,r3 ，F u3,r3 ，F r3,u4 In addition, other flow without pipeline connection in the steam network energy expansion transformation optimization model is set to zero, such as F r1,u3 =0, etc.
5. The steam flow for the four devices operating at baseline design conditions, maximum load, and minimum load is shown in the following table, with device u4 being the new device.
6. And (5) establishing a steam system operation energy expansion transformation optimization model. The optimization objective of the model is that the annual total cost is minimum. .
7. Solving the optimization model to obtain an optimal transformation scheme. In order to meet the steam requirements of each grade of the newly-built device u4, a medium-pressure steam pipeline with the flow rate of 32000kg/h is required to be newly built, 1 steam turbine is additionally added to feed high-pressure steam back pressure to produce low-pressure steam, the low-pressure steam requirement of the newly-built device is met, and meanwhile, the residual pressure energy of steam is fully recovered, so that the running cost of the device is reduced.
Example III
Fig. 4 is a schematic diagram of a hardware structure of a steam system energy expansion transformation optimization electronic device according to the present invention, including:
at least one processor 401; the method comprises the steps of,
a memory 402 communicatively coupled to at least one of the processors 401; wherein,
the memory 402 stores instructions executable by at least one of the processors 401, the instructions being executable by at least one of the processors 401 to enable at least one of the processors 401 to perform a steam system expansion retrofitting optimization method as previously described.
One processor 401 is illustrated in fig. 4.
The electronic device may further include: an input device 403 and a display device 404.
The processor 401, memory 402, input device 403, and display device 404 may be connected by a bus or other means, which is illustrated as a bus connection.
The memory 402 is used as a non-volatile computer readable storage medium, and may be used to store a non-volatile software program, a non-volatile computer executable program, and modules, such as program instructions/modules corresponding to the steam system expansion improvement optimization method in the embodiment of the present application, for example, a method flow shown in fig. 1. The processor 401 executes various functional applications and data processing by running non-volatile software programs, instructions and modules stored in the memory 402, i.e. implements the steam system expansion improvement optimization method in the above-described embodiments.
Memory 402 may include a storage program area that may store an operating system, at least one application program required for functionality, and a storage data area; the storage data area may store data created according to the use of steam system expansion optimization methods, etc. In addition, memory 402 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 402 optionally includes memory remotely located with respect to processor 401, which may be connected via a network to a device performing the steam system power retrofit optimization method. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The input device 403 may receive input user clicks and generate signal inputs related to user settings and function control of the steam system expansion improvement optimization method. The display 404 may include a display device such as a display screen.
The steam system expansion optimization method of any of the method embodiments described above is performed when the one or more modules are stored in the memory 402 and when executed by the one or more processors 401.
Aiming at the steam and power demand change brought by the expansion transformation of the existing device and the newly-built device of the petrochemical enterprise, the invention fully utilizes the capability of the existing equipment to reduce the investment of newly-added equipment on the premise of meeting the steam demand of each production device of the enterprise under different production loads, and automatically obtains the transformation scheme with the lowest comprehensive cost of the existing steam system through system optimization on the premise of ensuring the safety and stability of the actual operation process of the steam system, thereby being beneficial to improving the economic competitiveness of the enterprise.
An embodiment of the invention provides a storage medium storing computer instructions that, when executed by a computer, perform all the steps of a steam system expansion retrofitting optimization method as described above.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (8)
1. A steam system energy expansion transformation optimization method, comprising:
obtaining design variables of a boiler, a temperature and pressure reducer, a turbine and a steam main pipe of the existing steam system;
based on the design variables, constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam manifold and a temperature and pressure reducer of the existing steam system;
based on the existing steam system, taking design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe as solving values, constructing a steam system to be modified, and constructing a mass balance formula and an energy balance formula of each turbine, each stage of steam header pipe and the temperature and pressure reducer of the steam system to be modified;
Establishing capacity constraint conditions, wherein the capacity constraint conditions are the maximum capacity of a boiler, a turbine and a temperature and pressure reducer existing in the existing steam system and the upper and lower limit constraint of the flow of a pipeline;
establishing a usage constraint condition, wherein the usage constraint condition is the usage and the yield of steam under the maximum operation load of each device using the output energy of the steam system and the usage and the yield of steam under the minimum operation load of each device;
establishing an objective function for minimizing the sum of annual investment cost and operation cost of a newly added boiler, a newly added temperature and pressure reducer, a newly added turbine and a newly added steam header pipe;
solving the objective function based on the mass balance formula, the energy balance formula, the capacity constraint condition and the consumption constraint condition to obtain design variables of a new boiler, a new temperature and pressure reducer, a new turbine and a new steam header pipe of the steam system to be modified;
based on the design variables, a mass balance formula and an energy balance formula of each turbine, each stage of steam manifold and a temperature and pressure reducer thereof of the existing steam system are constructed, and the mass balance formula and the energy balance formula specifically comprise:
constructing a mass balance formula of steam flow of a steam manifold entering and exiting the existing steam system:
；
Constructing an energy balance formula of steam flow of a steam manifold into and out of an existing steam system:
；
wherein F represents steam flow, h represents specific enthalpy of the stream, subscript b represents a b-th boiler of the existing steam system, subscript r represents a r-th steam manifold of the existing steam system, subscript t represents a t-th turbine of the existing steam system, and subscript d represents the existing steamThe d-th attemperator of the steam system, subscript u denotes the u-th device using the output energy of the steam system, F r,loss Indicating the leakage loss of the (r) th steam header,for r-stage steam usage of unit u, +.>For the r-stage steam yield of unit u, subscript +.>Represents the newly added b' th boiler and subscript +.>Indicate the added->Individual turbines, subscripts->D' th temperature and pressure reducer and subscript for new addition>Representing an added r' th steam header pipe;
wherein the method comprises the steps ofAnd (2) and；
in the method, in the process of the invention,indicating the specific enthalpy of the steam produced by the boiler, +.>Indicating the specific enthalpy of boiler feed water, +.>Indicating the thermal efficiency of boiler b, +.>Indicating the amount of fuel consumed by boiler b, +.>Representing the low heating value of the fuel;
and constructing a mass balance formula of inlet and outlet steam of a turbine of the existing steam system:
；
constructing an energy balance formula of inlet and outlet steam of a turbine of the existing steam system: Wherein->The work output by the turbine t to the outside is represented;
constructing a mass balance formula of a temperature and pressure reducer of the existing steam system:
；
constructing an energy balance formula of a temperature and pressure reducer of the existing steam system:
wherein->Represents the water supplement quantity of the temperature and pressure reducer d, < ->Indicating the specific enthalpy of the boiler water, +.>Representing the specific enthalpy of the steam after decompression and temperature reduction;
the objective function for minimizing the sum of annual investment cost and operation cost of a newly added boiler, a newly added temperature and pressure reducer, a newly added turbine and a newly added steam header pipe is established, and specifically comprises the following steps:
establishing an objective function:
；
wherein A is an annual factor of equipment investment cost, C is an equipment investment cost coefficient, τ is annual operation time, and P f Indicating the unit price of fuel, W indicates the total electricity consumption of the existing device and the newly built device when all steam turbines are not started, and P e Indicating electricity price, subscriptRepresents the newly added b' th boiler and subscript +.>Indicate the added->Individual turbines, subscripts->D' th temperature and pressure reducer and subscript for new addition>Representing the newly added r' th steam header.
2. The method for optimizing the energy expansion transformation of the steam system according to claim 1, wherein the construction of the mass balance formula and the energy balance formula of each turbine, each stage of steam manifold and the temperature and pressure reducer thereof of the steam system to be transformed specifically comprises the following steps:
Constructing a mass balance formula of steam flow of an newly added steam header pipe entering and exiting a steam system to be modified:
；
constructing an energy balance formula of steam flow of a newly added steam header pipe of an existing steam system:
；
wherein the method comprises the steps ofAnd (2) and；
in the middle ofRepresenting new boiler->Is>Representing new boiler->The amount of fuel consumed, F r’,loss Indicating the leakage loss of the newly added r' steam header pipe;
constructing a mass balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified:
；
constructing an energy balance formula of inlet and outlet steam of a newly added turbine of a steam system to be modified:
wherein->Representing a new turbine->Work output to the outside;
constructing a mass balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified:
；
constructing an energy balance formula of a new temperature-increasing and reducing pressure reducer of a steam system to be modified:
in which, in the process,indicating the new temperature-increasing and reducing pressure reducer->Is added with water>Indicating the specific enthalpy of the steam after depressurization and temperature reduction.
3. The steam system expansion transformation optimization method according to claim 1, wherein the establishment of capacity constraint conditions specifically comprises:
defining steam flow rate produced by each boilerWherein->For the steam flow of boiler b>Is the maximum capacity of the boiler b;
Defining steam flow for each turbineWhereinRepresenting the inlet flow of the t turbine connected with the b boiler, F r,t Represents the outlet flow of the t turbine connected to the r steam header, the +.>Maximum allowable steam flow for the t turbine;
defining steam flow for each desuperheaterWherein->For the steam flow of the d-th desuperheater connected to the r-th steam header,/v>Maximum allowable steam flow for the d-th desuperheater;
defining steam flow between nodes p and q in a steam pipe network in an existing steam systemAnd (2) andwherein->Representing the lowest safe flow between node p and node q in the existing steam pipe network,representing the highest safe flow between node p and node q in the existing steam pipe network.
4. A steam system expansion retrofitting optimization method according to claim 3 and wherein said defining steam flow between node p and node q in a steam pipe network in an existing steam system further comprises:
the steam flow between nodes in the steam pipe network where no connection exists is set to 0.
5. The steam system expansion transformation optimization method according to claim 1, wherein the establishing the usage constraint condition specifically comprises:
LimitingAnd->；
Wherein,for the steam quantity of the (u) th device connected to the (r) th steam header at maximum operating load, (-)>For the steam production of the (u) th device connected to the (r) th steam header at maximum operating load, is provided>For the steam quantity of the (u) th device connected to the (r) th steam header at minimum operating load, (-)>For the steam production at minimum operating load of the u-th device connected to the r-th steam header, x is a binary variable which can only take on a value of 0 or 1.
6. The steam system expansion revamping optimization method of claim 1, wherein the annual factor；
Where i represents the annual rate of funds and n represents the depreciated years of the device.
7. A steam system energy expansion retrofit optimization electronic device, comprising:
at least one processor; the method comprises the steps of,
a memory communicatively coupled to at least one of the processors; wherein,
the memory stores instructions executable by at least one of the processors to enable the at least one of the processors to perform the steam system expansion optimization method of any of claims 1-6.
8. A storage medium storing computer instructions which, when executed by a computer, are adapted to perform all the steps of the steam system expansion revamping optimization method according to any one of claims 1-6.
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