阅读说明：本技术 一种减压炉连弩控制系统及方法 (Decompression furnace repeating crossbow control system and method ) 是由 李全善 王文新 徐开慧 于 2020-12-22 设计创作，主要内容包括：本发明涉及一种减压炉连弩控制系统,包括：一个或多个支路进料流量控制模块FB-i,经配置以控制支路进料流量FSV-i；一个或多个支路出口温度控制模块TB-i,经配置以控制支路进料流量的变化量TC-i；炉膛温度控制模块T-(CF),用于控制进入的燃料气流量FC-G；以及出口温度控制模块T-C,出口温度指的是多个支路出口温度的平均温度,其与所述炉膛温度控制模块T-(CF)组成串级控制回路。本发明还涉及一种减压炉连弩控制方法,有效减少减压炉运行过程及常压塔液位调整过程中的支路温度的波动,提高减压炉整体运行的平稳性。(The invention relates to a decompression furnace repeating crossbow control system, which comprises: one or more branch feed flow control modules FB i Configured to control the bypass feed flow FSV i (ii) a One or more branch outlet temperature control modules TB i A variable quantity TC configured to control the bypass feed flow i (ii) a Hearth temperature control module T CF For controlling the incoming fuel gas flow FC G (ii) a And an outlet temperature control module T C The outlet temperature refers to the average temperature of the outlet temperatures of a plurality of branches, and is connected with the furnace temperature control module T CF Forming a cascade control loop. The invention also relates to a repeating crossbow control method for the pressure reducing furnace, which effectively reduces the fluctuation of branch temperature in the operation process of the pressure reducing furnace and the liquid level adjustment process of the normal pressure tower and improves the overall operation stability of the pressure reducing furnace.)

1. A decompression furnace repeating crossbow control system comprising:

one or more branch feed flow control modules FB_iConfigured to control the bypass feed flow FSV_i；

One or more branch outlet temperature control modules TB_iA variable quantity TC configured to control the bypass feed flow_i；

Hearth temperature control module T_CFFor controlling the incoming fuel gas flow FC_G(ii) a And

outlet temperature control module T_CWith said furnace temperature control module T_CFForming a cascade control loop.

2. The system of claim 1, wherein the one or more branch outlet temperature control modules TB_iIncluding one or more branch outlet temperatures T_OUTi。

3. The system of claim 1, further comprising a calculation module configured and arranged to calculate one or more leg feed adjustment delta and STC_HPDAnd decrement and STC_HPR，

Wherein the increment is

Wherein the decrement is

4. The system of claim 3 further comprising a limit STC for each leg adjustment_DREWherein STC_DRE＝min(STC_HPD,abs(STC_HPR))；

The delta and STC_HPDFurther comprising a delta coefficient C_HPDIn which C is_HPD＝STC_DRE/STC_HPD；

The decrement and STC_HPRFurther comprises a decrement coefficient C_HPRIn which C is_HPR＝STC_DRE/STC_HPR。

5. The system of claims 1 and 4 wherein the limit STC for each leg adjustment amount_DREThe single maximum increment or maximum decrement is DSV;

wherein, a single maximum adjustment increment or maximum adjustment decrement DF is also included_BLAnd a single adjustment coefficient C_BL；DF_BL＝min(STC_DRE,DSV)，C_BL＝DF_BL/STC_DRE；

Wherein, the method also comprises the single adjustment DFSV of branch feeding quantity_i，

Said by-pass feed flow FSV_i＝FSV_i+DFSV_i。

6. The system of claim 5, further comprising a reduced pressure furnace Load Setpoint (LSV) output by the atmospheric tower level controller, the bypass feed flow rate

7. The system of claim 1, the outlet temperature control module T_CThe temperature control range of (1) is 300-450 ℃.

8. A decompression furnace repeating crossbow control method comprises the following steps:

control bypass feed flow FSV_i；

Variable TC for controlling branch feeding flow_i；

Controlling incoming fuel gas flow FC_G(ii) a And forming a cascade control loop.

9. The method of claim 7, calculating one or more bypass feed adjustmentsVolume increment and STC_HPDAnd decrement and STC_HPR，

Wherein the increment is

Wherein the decrement is

10. The method of claim 8 further comprising a limit STC for each leg adjustment_DREWherein STC_DRE＝min(STC_HPD,abs(STC_HPR))；

The delta and STC_HPDFurther comprising a delta coefficient C_HPDIn which C is_HPD＝STC_DRE/STC_HPD；

The decrement and STC_HPRFurther comprises a decrement coefficient C_HPRIn which C is_HPR＝STC_DRE/STC_HPR。

Technical Field

The invention relates to the field of petrochemical industry, in particular to a system and a method for controlling a repeating crossbow of a decompression furnace.

Background

In the production process of the oil refining device, the decompression furnace is a key device for influencing the fractionation effect of a target product, so that the efficient and stable operation of the decompression furnace is very important. The decompression furnace is generally a tubular heating furnace, which utilizes high-temperature flame and flue gas generated when fuel is combusted in a hearth as heat sources, and the material flowing at high speed in the decompression furnace reaches the temperature required by a subsequent decompression tower. In order to reduce the pressure drop of the furnace tubes and save energy, the raw materials are heated uniformly, the pressure reducing furnace is designed by adopting a plurality of paths of furnace tubes, but the phenomenon of 'biased fire' often occurs due to the imbalance of the fuel of each burner, the air supply quantity and the like, so that the outlet temperature of each group of furnace tubes is unbalanced, the possibility of coking of the furnace tubes is increased, and the service life of the furnace tubes is shortened. The temperature of the branch furnace tube needs to be balanced and controlled, so that the temperature difference of each branch of the pressure reducing furnace is minimum and is close to the temperature of the outlet of the furnace. Meanwhile, the load of the pressure reducing furnace is influenced by the liquid level of the upstream high-pressure tower, the liquid level controller of the normal-pressure tower and the feeding flow controllers of all branches of the pressure reducing furnace are in cascade connection, and the flow of all branches of the pressure reducing furnace needs to be adjusted at any time to ensure the stable liquid level of the normal-pressure tower, so that the operating characteristics of the pressure reducing furnace are changed, the temperature of an outlet and the temperature of the branches are disturbed, and the factor needs to be considered in the temperature control of the pressure reducing.

Therefore, the invention provides a decompression furnace repeating crossbow control system and method with a brand-new concept, and the repeating crossbow control concept is from a weapon which is manufactured by Zhuge Liang in the three kingdoms and can be used for issuing a plurality of arrows at the same time. The invention introduces the idea that the crossbow emits a plurality of arrows at the same time into the control scheme of the decompression furnace, and establishes the decompression furnace crossbow control system.

The load change of the pressure reducing furnace is influenced by the liquid level change of the normal pressure tower, and the liquid level controller of the normal pressure tower is cascaded with the feed flow controllers of the branches of the pressure reducing furnace. Based on the principle of heat transfer, the temperature of each branch is taken as a measured value, the temperature of the furnace outlet is taken as a set value, a branch temperature controller is established, the output of the branch temperature controller is taken as the raw material flow adjustment required by the branch, and the cascade adjustment of the branch flow by the atmospheric tower is considered. The branch balancing and load adjustment is simultaneously carried out on each branch, the branch with high branch temperature increases the feeding amount, the branch with low branch temperature decreases the feeding amount, the feeding amount is increased or decreased simultaneously along with the liquid level adjustment of the atmospheric tower on each branch, and the load adjustment is realized on the premise of ensuring the branch balancing.

Disclosure of Invention

Aiming at the problems in the prior art, the invention discloses a decompression furnace repeating crossbow control system, which comprises: one or more branch raw material feed flow control modules FB_iIs configured to control the branchWay feed flow FSV_i(ii) a Liquid level control module L of atmospheric tower_CWith one or more branch raw material feed flow control modules FB_iForming a cascade control loop; one or more branch outlet temperature control modules TB_iA variable quantity TC configured to control the bypass feed flow_i(ii) a Hearth temperature control module T_CFFor controlling the incoming fuel gas flow FC_G(ii) a And an outlet temperature control module T_CThe outlet temperature refers to the average temperature of the outlet temperatures of a plurality of branches, and is connected with the furnace temperature control module T_CFForming a cascade control loop.

Further, the repeating crossbow control system, wherein the one or more branch outlet temperature control modules TB_iCorresponding to one or more branch outlet temperatures T_OUTi。

Further, the repeating crossbow control system further comprises a calculation module configured to calculate one or more branch feed adjustment increment and STC_HPDAnd decrement and STC_HPRWherein the increment isWherein the decrement is

Furthermore, the repeating crossbow control system also comprises limit values STC of the adjustment quantity of each branch_DREWherein STC_DRE＝min(STC_HPD,abs(STC_HPR) ); the delta and STC_HPDFurther comprising a delta coefficient C_HPDIn which C is_HPD＝STC_DRE/STC_HPD(ii) a The decrement and STC_HPRFurther comprises a decrement coefficient C_HPRIn which C is_HPR＝STC_DRE/STC_HPR。

Further, the repeating crossbow control system, wherein the limit value STC of each branch adjusting quantity_DREThe single maximum increment or maximum decrement is DSV; wherein, the method also comprises a single maximum adjustment increment or maximum adjustment decrement DF_BLAnd a single adjustment coefficient C_BL；DF_BL＝min(STC_DRE,DSV)，C_BL＝DF_BL/STC_DRE(ii) a Wherein, the method also comprises the single adjustment DFSV of branch feeding quantity_i，Said by-pass feed flow FSV_i＝FSV_i+DFSV_i。

Further, the repeating crossbow control system also comprises a pressure reducing furnace load set value LSV output by the normal-pressure tower liquid level controller, and the branch feeding flow rate

Further, the repeating crossbow control system comprises an outlet temperature control module T_CThe temperature control range of (1) is 300-450 ℃.

The invention discloses a method for controlling a repeating crossbow of a decompression furnace, which comprises the following steps: control bypass feed flow FSV_i(ii) a Variable TC for controlling branch feeding flow_i(ii) a Controlling incoming fuel gas flow FC_G(ii) a And forming a cascade control loop.

Further, the repeating crossbow control method calculates the feed adjustment increment of one or more branches and STC_HPDAnd decrement and STC_HPRWherein the increment isWherein the decrement is

Further, the repeating crossbow control method also comprises limit STC of each branch adjusting quantity_DREWherein STC_DRE＝min(STC_HPD,abs(STC_HPR) ); the delta and STC_HPDFurther comprising a delta coefficient C_HPDIn which C is_HPD＝STC_DRE/STC_HPD(ii) a The decrement and STC_HPRAlso comprisesDecrement coefficient C_HPRIn which C is_HPR＝STC_DRE/STC_HPR。

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a block diagram of a decompression furnace repeating crossbow control system according to one embodiment of the present invention;

fig. 2 is a structural diagram of a decompression furnace repeating crossbow control operation module according to an embodiment of the invention;

fig. 3 is a schematic structural diagram of a decompression furnace repeating crossbow control system according to another embodiment of the invention;

FIG. 4 is a graph of temperature operation of the decompression furnace with crossbow control before implementation, in accordance with the embodiment of the present invention shown in FIG. 3;

FIG. 5 is a graph of temperature operation after the implementation of the decompression furnace crossbow control in accordance with the embodiment of the present invention shown in FIG. 3;

fig. 6 is a flowchart of a method for controlling a repeating crossbow in a decompression furnace according to an embodiment of the present invention.

Reference numerals:

101-a decompression furnace; 102-a repeating crossbow control module;

103-first branch feed flow; 103' -ith branch feed flow;

104-a first branch feed flow control module; 104' -the ith branch feed flow control module;

105-a first branch outlet temperature control module; 105' -the ith branch outlet temperature control module;

106-first branch outlet temperature; 106' -ith branch outlet temperature;

107-outlet temperature control module; 108-furnace temperature control module;

109-fuel gas flow; 110-atmospheric tower liquid level control module;

201-a decompression furnace repeating crossbow controller; 301-vacuum furnace;

302-repeating crossbow controller; 303-outlet temperature controller;

304-furnace temperature controller; 305-atmospheric tower liquid level controller;

331-first branch outlet temperature controller; 332-second branch outlet temperature controller;

338-eighth branch outlet temperature controller; 311-first branch flow controller;

312-a second branch flow controller; 318-eighth branch flow controller.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof and in which is shown by way of illustration specific embodiments of the application. In the drawings, like numerals describe substantially similar components throughout the different views. Various specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to practice the teachings of the present application. It is to be understood that other embodiments may be utilized and structural, logical or electrical changes may be made to the embodiments of the present application.

The technical solution of the present invention is further illustrated by a specific example. It should be understood by those skilled in the art that the following descriptions are only for convenience in understanding the technical solutions of the present invention and should not be used to limit the scope of the present invention.

FIG. 1 is a schematic view ofThe structure of the decompression furnace repeating crossbow control system in one embodiment of the invention. As shown in the figure, the feeding flow of the depressurization furnace has n groups, and the depressurization furnace 101 crossbow control system comprises a crossbow control module 102, a first branch feeding flow 103, an ith branch feeding flow 103', a first branch feeding flow control module 104, an ith branch feeding flow control module 104', a first branch outlet temperature control module 105, an ith branch outlet temperature control module 105', a first branch outlet temperature 106, an ith branch outlet temperature 106', an outlet temperature control module 107, a hearth temperature control module 108 and a fuel gas flow 109. Wherein, the first branch feed flow control module 104 and the ith branch feed flow control module 104' are one or more branch feed flow control modules FB in the illustrated embodiment_iConfigured to control the corresponding branch feed flow FSV_iNamely the first branch feed flow 103 and the ith branch feed flow 103'.

The input of the outlet temperature control module is connected with an outlet temperature measuring instrument; the input of the feed flow control module is connected with a flow measuring instrument, and the output of the feed flow control module is sent to a branch flow regulating valve; the input of the hearth temperature control module is connected with a fuel gas pressure measuring instrument, and the output of the hearth temperature control module is sent to a fuel gas flow regulating valve. The temperature measuring instrument can be of a contact type or a non-contact type, and comprises but is not limited to a thermal resistor, a thermocouple and the like; flow meters include, but are not limited to, differential pressure flow meters, rotameters, electromagnetic flow meters, and the like.

As shown in fig. 1, the repeating crossbow control system of the decompression furnace 101 according to one embodiment of the present invention includes a first branch outlet temperature control module 105 and an ith branch outlet temperature control module 105' which are one or more branch outlet temperature control modules TB_iA variable quantity TC configured to control the bypass feed flow_i. 101 hearth temperature control module T of pressure reducing furnace_CB108 for controlling the fuel gas flow FC into the decompression furnace 101_G109. Decompression furnace 101 outlet temperature control module T_C107 which forms a cascade control loop with a furnace temperature control module PC108 of the decompression furnace 101. Regulation of fuel gas flow FC by furnace temperature control module PC108_G109 to effect regulation of the outlet temperature.

105, 105' one or more branch outlet temperature control modules TB as shown in FIG. 1_iCorrespondingly comprising 106, 106' one or more branch outlet temperatures T_OUTi. The adjusting method of repeating crossbow control comprises the steps of increasing feeding flow of branches with high branch temperature and reducing feeding flow of branches with low branch temperature. For a single branch, in order to keep the heat balance of the single branch before and after adjustment, the heat of the branch before and after adjustment is consistent, according to the heat conservation principle and the heat transfer rate equation, the following expression is given:

Q＝Cp×FSV_i×(T_OUTi-T_C)＝Cp×TC_i×(T_C-T_INi) (1)

in the formula, TC_iVariation of branch feed flow, FSV, to be adjusted for the ith branch_iFor this branch the feed flow 103', Q represents the sum of the heat transferred before and after the regulation, T_INiIs the inlet temperature, T, of the ith branch of the pressure reducing furnace_OUTiIs the outlet temperature 106' of the ith branch of the decompression furnace and the outlet temperature control module T of the decompression furnace_C 107。

The repeating crossbow control system further comprises a calculating module, wherein the calculating module is used for calculating increment and decrement sum of one or more branch feeding adjusting amount, and the following expressions are provided:

in the formula, STC_HPDRepresents the incremental sum, STC, of the branch feed adjustments_HPRRepresenting the decrement sum of the bypass feed adjustment.

According to the feeding amount, the limit value of the adjustment amount of each branch can be further calculatedAnd corresponding STC_HPDDelta coefficient of delta sum, STC_HPRThe decrement coefficient of the decrement sum is specifically as follows:

STC_DRE＝min(STC_HPD,abs(STC_HPR)) (5)

C_HPD＝STC_DRE/STC_HPD (6)

C_HPR＝STC_DRE/STC_HPR (7)

STC_DRElimiting the adjustment of each branch, C_HPDAs a branch increment factor, C_HPRIs the branch decrement coefficient.

Wherein, the limit value STC of each branch adjusting quantity in the repeating crossbow control system is set_DREThe single maximum increment or maximum decrement is DSV, and the allocation relationship is as follows:

DF_BL＝min(STC_DRE,DSV) (8)

C_BL＝DF_BL/STC_DRE (9)

DF in formula_BLFor single maximum adjustment increments or maximum adjustment decrements, C_BLIs a single adjustment factor. Single adjustment of each branch feeding DFSV_iComprises the following steps:

final adjusted branch feed flow FSV for each branch_i103' is:

FSV_i＝FSV_i+DFSV_i (11)

the total load of the vacuum furnace is the output LSV of the liquid level controller of the atmospheric tower, and the feeding flow FSV of each branch_i103' is calculated as:

according to one embodiment of the invention, the outlet temperature control module T of the decompression furnace_C107 in the temperature control range300℃-450℃。

Fig. 2 is a structural diagram of a decompression furnace repeating crossbow control operation module according to an embodiment of the invention. As shown, the decompression furnace repeating crossbow controller 201 is used for reading the inlet temperature T of the decompression furnace branch_INiOutlet temperature T_OUTiAnd a bypass feed flow FV_iEach branch adjusts the single maximum increment or maximum decrement DSV of the flow, the total load value QSV;

setting single branch single maximum adjustment increment and STC (coefficient of performance) as shown in figures 1 and 2_HPDWith maximum adjustment decrement and STC_HPR. According to the control principle of the repeating crossbow of the decompression furnace, a repeating crossbow control module 102 is developed on DCS, and is loaded and debugged in a control system. And the repeating crossbow control module calculates and obtains the adjustment DFSV of each branch. Reading the load value LSV of the total load set value of the decompression furnace, and calculating to obtain the set value FSV of the branch flow controller according to the repeating crossbow control module 102_i。

Compared with the traditional control method, the control method of the repeating crossbow of the decompression furnace has the following advantages that: aiming at the problem that the branch outlet temperature has deviation in the normal operation process of the pressure reducing furnace and the liquid level adjustment process of the normal pressure tower, the heat balance before and after adjustment is kept based on the principle of heat balance, the repeating crossbow control method of the pressure reducing furnace is provided, the feeding quantity of each branch is adjusted at the same time, the purpose of reducing the temperature fluctuation of the branch is realized, the fluctuation of the branch temperature in the operation process of the pressure reducing furnace and the liquid level adjustment process of the normal pressure tower is effectively reduced, and the overall operation stability of the pressure reducing furnace is improved.

Fig. 3 is a schematic structural diagram of a decompression furnace repeating crossbow control system according to another embodiment of the invention. As shown, the depressurization furnace 301 has eight branches of feed, including a repeating crossbow control module 302, an outlet temperature control module 303, and a furnace temperature control module 304.

Fig. 4 is a graph showing temperature operation before the implementation of the decompression furnace crossbow control according to the embodiment of the present invention shown in fig. 3, and fig. 5 is a graph showing temperature operation after the implementation of the decompression furnace crossbow control according to the embodiment of the present invention shown in fig. 3.

As shown in fig. 3, 4, and 5, the repeating crossbow control module 302 is used to control the temperature difference of each branch due to the non-uniform combustion temperature distribution in the decompression furnace. Wherein the furnace inlet feed is provided with a first branch flow meter 311, a second branch flow meter 312, … … and an eighth branch flow meter 318 respectively. A first branch outlet temperature controller 331, a second branch outlet temperature controller 332, … …, and an eighth branch outlet temperature controller 338. In order to control the temperature difference of the branch circuits, a pressure reducing furnace crossbow control module is developed and is installed and implemented in a DCS system, so that the aim of reducing the temperature difference of the branch circuits is fulfilled.

As shown in fig. 4 and 5, before the repeating crossbow control of the decompression furnace is implemented, the outlet temperature of the decompression furnace and the feeding of eight branches fluctuate within a certain range. After the repeating crossbow control is implemented, the operation curves of the furnace outlet temperature and the eight branch temperature are stable, and the whole stable operation of the decompression furnace is facilitated.

Fig. 6 is a flowchart of a method for controlling a repeating crossbow in a decompression furnace according to an embodiment of the present invention.

In step 610, the bypass feed flow is controlled. As previously described, according to embodiments of the present invention, controllability of the flow volume is achieved using one or more bypass feed flow control modules.

In step 620, the amount of change in the bypass feed flow is controlled. And the quantification of branch feeding flow temperature data is realized through one or more branch outlet temperature control modules.

In step 630, the incoming fuel gas flow is controlled. As previously described, the fuel gas flow rate is regulated using a furnace temperature controller.

In step 640, a cascade control loop is formed. A cascade control loop can be formed by the outlet temperature control module and the hearth temperature control module.

The above embodiments are provided for illustrative purposes only and are not intended to limit the present invention, and various changes and modifications may be made by those skilled in the relevant art without departing from the scope of the present invention, and therefore, all equivalent technical solutions should fall within the scope of the present disclosure.