阅读说明：本技术 回收塔再沸器热源控制系统 (Heat source control system of reboiler of recovery tower ) 是由 陆玲 李大伟 王帅 霍宝胜 刘俊凯 金娜 吴楠 王振兴 杨忠祥 于 2019-09-05 设计创作，主要内容包括：本发明涉及一种回收塔再沸器热源控制系统,包括:再沸器热源主管(1),连接回收塔再沸器；再沸器热源支管(2),并联在所述再沸器热源主管(1)上；所述再沸器热源支管(2)上设有流量调节阀(201)；还包括:回收塔温控器(3),监测回收塔内温度,将测得温度与阈值进行比较后输出至所述流量调节阀(201)；所述流量调节阀(201)与所述回收塔温控器(3)串级调节。本发明能满足系统小范围流量控制需要,并能实现高精度调节热源流量。(The invention relates to a heat source control system of a reboiler of a recovery tower, which comprises a reboiler heat source main pipe (1) connected with the reboiler of the recovery tower; a reboiler heat source branch pipe (2) connected in parallel to the reboiler heat source main pipe (1); a flow regulating valve (201) is arranged on the reboiler heat source branch pipe (2); the recovery tower temperature controller (3) is used for monitoring the temperature in the recovery tower, comparing the measured temperature with a threshold value and outputting the temperature to the flow regulating valve (201); and the flow regulating valve (201) and the recovery tower temperature controller (3) are in cascade regulation. The invention can meet the small-range flow control requirement of the system and can realize high-precision adjustment of the flow of the heat source.)

1. A recovery column reboiler heat source control system comprising:

a reboiler heat source main pipe (1) connected with the recovery tower reboiler;

a reboiler heat source branch pipe (2) connected in parallel to the reboiler heat source main pipe (1);

a flow regulating valve (201) is arranged on the reboiler heat source branch pipe (2);

the recovery tower temperature controller (3) is used for monitoring the temperature in the recovery tower, comparing the measured temperature with a threshold value and outputting the temperature to the flow regulating valve (201);

and the flow regulating valve (201) and the recovery tower temperature controller (3) are in cascade regulation.

2. The system for controlling the heat source of the reboiler of a recovery column according to claim 1, wherein a flow meter (101) for measuring the total amount of the heat source steam required for the reboiler of the recovery column is provided in the reboiler heat source main pipe (1).

3. The recovery tower reboiler heat source control system according to claim 1, wherein the reboiler heat source main pipe (1) is further provided with a DCS manual switching valve (102) for controlling a flow rate of the heat source steam in the reboiler heat source main pipe (1).

4. The recovery column reboiler heat source control system according to claim 1, wherein a heat source steam flow in the reboiler heat source main (1) is larger than a heat source steam flow in the reboiler heat source branch (2).

5. The recovery column reboiler heat source control system of claim 4, wherein the ratio of the heat source steam flow in the reboiler heat source branch pipe (2) to the heat source steam flow in the reboiler heat source main pipe (1) is between 1:5 and 1: 2.2.

6. The recovery column reboiler heat source control system of claim 5, wherein the ratio of the heat source steam flow in the reboiler heat source branch pipe (2) to the heat source steam flow in the reboiler heat source main pipe (1) is between 1:4 and 1: 2.3.

7. The recovery column reboiler heat source control system according to claim 6, wherein the ratio of the heat source steam flow in the reboiler heat source branch pipe (2) to the heat source steam flow in the reboiler heat source main pipe (1) is 1: 4.

Technical Field

The invention relates to the field of acrylonitrile production, in particular to a heat source control system of a reboiler of a recovery tower.

Background

The production technology of acrylonitrile in the world mainly adopts propylene and ammoxidation methods. In recent decades, with the continuous updating of catalysts and the continuous improvement of process flows, the process technology route for preparing acrylonitrile by propylene and ammoxidation still keeps the leading position.

The process flow of the acrylonitrile main device comprises a reaction part, a recovery part, a refining part and a four-effect evaporation part. The recovery column of the refining section is an extractive distillation column using water as a solvent, and functions to recover and separate acrylonitrile, hydrocyanic acid, and acetonitrile from an absorption liquid (rich water). Acrylonitrile and hydrocyanic acid were distilled off from the column top, a liquid containing acetonitrile was taken out from the side line of the column, and water taken out from the first tray was used as absorption water and solvent water (referred to as lean water). A reboiler at the tower bottom of the recovery tower takes low-pressure steam as a heat source, and the flow rate of the low-pressure steam and the temperature of a sensitive point of the tower are adjusted in a cascade mode.

In the prior art, the caliber of the switch type valve can be very large, for example, more than 1 meter; the regulating valve is affected by flow characteristics, and a large-diameter valve is difficult to manufacture, so that the production cost is greatly increased. And the large-diameter regulating valve can only adopt butterfly valves with approximate equal percentage, and the flow change caused by the tiny change of the valve opening is large, the regulating precision is low, thereby affecting the product index of the tower and even causing the unstable operation of the whole device.

Disclosure of Invention

The invention aims to solve the problems and provides a heat source control system for a reboiler of a recovery tower.

In order to achieve the above object, the present invention provides a heat source control system for a reboiler of a recovery column, comprising:

the reboiler heat source main pipe is connected with the recovery tower reboiler;

a reboiler heat source branch pipe connected in parallel to the reboiler heat source main pipe;

a flow regulating valve is arranged on the heat source branch pipe of the reboiler;

the temperature controller of the recovery tower is used for monitoring the temperature in the recovery tower, comparing the measured temperature with a threshold value and outputting the temperature to the flow regulating valve;

and the flow regulating valve and the temperature controller of the recovery tower are in cascade regulation.

According to one aspect of the invention, a flow meter for metering the total amount of heat source steam required by the reboiler of the recovery tower is arranged on the heat source main pipe of the reboiler.

According to one aspect of the invention, a DCS manual switch valve for controlling the flow of the heat source steam in the reboiler heat source main pipe is further arranged on the reboiler heat source main pipe.

According to an aspect of the invention, the heat source steam flow in the reboiler heat source main is greater than the heat source steam flow in the reboiler heat source branch.

According to an aspect of the invention, the ratio of the heat source steam flow in the reboiler heat source branch conduit to the heat source steam flow in the reboiler heat source main conduit is between 1:5 and 1: 2.2.

According to an aspect of the invention, the ratio of the heat source steam flow in the reboiler heat source branch conduit to the heat source steam flow in the reboiler heat source main conduit is between 1:4 and 1: 2.3.

According to an aspect of the invention, the ratio of the heat source steam flow in the reboiler heat source branch pipe to the heat source steam flow in the reboiler heat source main pipe is 1: 4.

According to one scheme of the invention, the flow regulating valve arranged on the heat source branch pipe of the reboiler is a small-caliber regulating valve, and can completely replace a large-caliber regulating valve by matching with a DCS manual switch valve, and the function of regulating the flow of the heat source with high precision can be realized.

According to one scheme of the invention, the reboiler heat source branch pipe is connected in parallel with the reboiler heat source main pipe, and only a small part of heat source steam flows through the reboiler heat source branch pipe, so that the requirement of controlling the flow of the system in a small range is met.

According to one scheme of the invention, the temperature controller of the recovery tower, which is arranged at the temperature sensitive point of the recovery tower, can accurately monitor the temperature at the sensitive point in the recovery tower, compares the measured temperature with a threshold value and outputs the temperature to the flow regulating valve, so that cascade regulation with the flow regulating valve is realized, and the regulation precision is further improved.

Drawings

FIG. 1 is a block diagram schematically illustrating a recovery column reboiler heat source control system in accordance with one embodiment of the present invention.

Detailed Description

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 will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.

FIG. 1 is a block diagram schematically illustrating a recovery column reboiler heat source control system in accordance with one embodiment of the present invention. As shown in fig. 1, the recovery tower reboiler heat source control system according to the present invention comprises a reboiler heat source main pipe 1, a reboiler heat source branch pipe 2, and a recovery tower temperature controller 3. The reboiler heat source main pipe 1 is connected with a recovery tower reboiler 4, the recovery tower reboiler 4 is provided with a material channel communicated with a material outlet 501 and a material inlet 502 on the recovery tower 5, so that the material channel can exchange heat with steam introduced into the recovery tower reboiler 4 from the reboiler heat source main pipe 1.

According to an embodiment of the invention, a flowmeter 101 is arranged on the reboiler heat source main pipe 1 and used for metering the total amount of heat source steam required by the recovery tower reboiler 4; the reboiler heat source branch pipe 2 is connected in parallel to the reboiler heat source main pipe 1, and is provided with a flow regulating valve 201. According to the concept of the present invention, the heat source steam flow rate in the reboiler heat source main pipe 1 should be greater than the heat source steam flow rate in the reboiler heat source branch pipe 2. The ratio of the heat source steam flow in the reboiler heat source branch pipe 2 to the heat source steam flow in the reboiler heat source main pipe 1 may be from 1:5 to 1:2.2, preferably from 1:4 to 1: 2.3.

According to one embodiment of the present invention, the ratio of the heat source steam flow in the reboiler heat source branch pipe 2 to the heat source steam flow in the reboiler heat source main pipe 1 is 1:4, i.e., 80% flow is passed through the reboiler heat source main pipe 1 and 20% flow is passed through the reboiler heat source branch pipe 2. In the present embodiment, the recovery tower temperature controller 3 is disposed at a temperature sensitive point of the recovery tower 5, and is adjusted in series with the flow regulating valve 201. The small fluctuation of the flow regulating valve 201 causes a large fluctuation in the temperature of the sensitive point of the recovery tower 5, and therefore the flow regulating valve 201 with good regulation performance should be selected to ensure the precision. The regulation performance of the flow regulating valve 201 has a direct relation with the valve type, and when the caliber is DN200 or below, a GLOBE regulating valve with equal percentage characteristics can be selected, so that the best regulation capacity is achieved. The cascade regulation is specifically that the temperature of a sensitive point of the recovery tower 5 is monitored by the recovery tower temperature controller 3, the measured temperature is compared with a threshold value and then is output to the flow regulating valve 201, then the flow regulating valve 201 regulates the flow of heat source steam in the reboiler heat source branch pipe 2, and the temperature of the sensitive point is controlled to be within a specified range, so that the flow is regulated within 20% of the total amount of the steam, the requirement of small-range flow control of the system is met, and high-precision regulation is realized.

According to an embodiment of the present invention, the reboiler heat source main pipe 1 is further provided with a DCS manual on-off valve 102 to control the flow rate of the heat source steam in the reboiler heat source main pipe 1.

According to the above embodiment of the present invention, the flow control valve 201 provided in the reboiler heat source branch pipe 2 is a small-diameter control valve, and can be used in combination with the DCS manual switching valve 102 to completely replace a large-diameter control valve, and can realize a function of highly accurately controlling the flow of the heat source. And the reboiler heat source branch pipe 2 is connected in parallel with the reboiler heat source main pipe 1, wherein only a small part of heat source steam flows, thereby meeting the requirement of the small-range flow control of the system. And the recovery tower temperature controller 3 that the temperature sensitive point department of recovery tower 5 set up can accurate monitoring recovery tower 5's sensitive point temperature to output to flow control valve 201 after will surveying temperature and threshold value and comparing, realize with flow control valve 201's cascade control, thereby further improve the regulation precision.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.