阅读说明：本技术 一种降低丁二烯装置溶剂自聚物的方法 (Method for reducing solvent autopolymer of butadiene device ) 是由 王展 张延涛 杨东旭 郝春波 武天希 于 2019-09-05 设计创作，主要内容包括：本发明属于乙腈法制取丁二烯技术领域,具体涉及一种通过加入阻聚剂降低丁二烯装置溶剂自聚物的方法。该方法通过在溶剂解析塔底部再沸器物料入口管线和釜液泵入口同时注入协同阻聚剂,使阻聚剂全方位无死角地进入溶剂中,有效地抑制乙腈溶剂中的各类含氧化合物在塔底及再沸器管程发生自聚反应,形成二聚物、多聚物等杂质,起到净化溶剂并延长再沸器使用周期的目的,实现装置安全、稳定、长周期、满负荷、优质运行。(The invention belongs to the technical field of butadiene preparation by an acetonitrile method, and particularly relates to a method for reducing solvent self-polymerization of a butadiene device by adding a polymerization inhibitor. The method simultaneously injects the synergistic polymerization inhibitor into a reboiler material inlet pipeline and a kettle liquid pump inlet at the bottom of the solvent analysis tower, so that the polymerization inhibitor enters the solvent in an all-around dead angle-free manner, effectively inhibits various oxygen-containing compounds in the acetonitrile solvent from generating self-polymerization at the tower bottom and a reboiler pipe side to form impurities such as dimer, polymer and the like, achieves the purposes of purifying the solvent and prolonging the service cycle of the reboiler, and realizes safe, stable, long-cycle, full-load and high-quality operation of the device.)

1. a method for reducing butadiene unit solvent autopolymer is characterized by comprising the steps of injecting a synergistic polymerization inhibitor into an inlet of a liquid pump of a desorption tower kettle, and circulating the polymerization inhibitor in a system together with a solvent; and injecting a synergistic polymerization inhibitor into a material inlet of a reboiler at the bottom of the desorption tower so that the polymerization inhibitor can inhibit the self-polymerization of materials in the reboiler in an all-around and dead-angle-free manner.

2. The method according to claim 1, wherein when the production load of the butadiene unit is 20t/h, the operating pressure of the desorption column is 0.43MPa, the temperature of the bottom of the column is controlled between 139 ℃ and 143 ℃, the amount of the polymerization inhibitor injected at the inlet of the liquid pump of the bottom of the column is 10.5g/min, and the amount of the polymerization inhibitor injected at the inlet of the reboiler at the bottom of the column is 1.5 g/min.

Technical Field

The invention belongs to the technical field of butadiene preparation by an acetonitrile method, and particularly relates to a method for reducing solvent self-polymerization of a butadiene device by adding a polymerization inhibitor.

Background

In the production process of extracting butadiene by using an acetonitrile method, a small amount of carbon dioxide, oxygen-containing compounds and other hydrocarbon impurities continuously enter a system along with the raw material carbon four, so that the oxygen-containing compounds, dimers and polymers are continuously generated in the butadiene extraction process, more and more impurities are contained in the solvent acetonitrile, if the impurities are not prevented in time, the quality of the solvent is reduced, the extraction and rectification effects are influenced, and equipment and pipelines are blocked and corroded more seriously. In the actual operation process of the device, a synergistic polymerization inhibitor and sodium nitrite are added at the solvent extraction pump inlet of the solvent desorption tower and the extraction tower, but a reboiler of the solvent desorption tower becomes a dead angle, and due to continuous formation and accumulation of impurities, a tube pass is seriously blocked, even the effect that the butadiene device must be stopped and cleaned once every half year is achieved, and the long-period, safe and high-quality operation of the butadiene device is directly influenced. The technical analysis shows that in the actual production process, acetonitrile at the tower bottom of the solvent analysis tower contains a very small amount of four carbon components (10ppm), and butadiene contains unsaturated bonds and has very high activity, so that a place with higher diene concentration is easy to polymerize through a free radical chain reaction to cause polymer generated by a tower tray and a reboiler structure to deposit on the reboiler to influence the heat transfer of the reboiler, and therefore, a trace amount of polymerization inhibitor needs to be injected into the reboiler to reduce equipment blockage and prolong the service cycle of the reboiler.

Disclosure of Invention

Technical problem to be solved

The invention provides a method for reducing solvent autopolymer of a butadiene device, which aims to solve the technical problems that the heat exchange effect is reduced and the long-period operation of the device is hindered because the bottom reboiler at the bottom is blocked by dimer formed by materials at the bottom of a solvent analysis tower of the butadiene device.

(II) technical scheme

In order to solve the technical problem, the invention provides a method for reducing butadiene device solvent self-polymerization, which comprises the steps of injecting a synergistic polymerization inhibitor at an inlet of a liquid pump of a desorption tower, and circulating the polymerization inhibitor in a system along with a solvent; and injecting a synergistic polymerization inhibitor into a material inlet of a reboiler at the bottom of the desorption tower so that the polymerization inhibitor can inhibit the self-polymerization of materials in the reboiler in an all-around and dead-angle-free manner.

Further, when the production load of the butadiene device is 20t/h, the operating pressure of the desorption tower is 0.43MPa, the temperature of the tower kettle is controlled between 139 ℃ and 143 ℃, the injection amount of the polymerization inhibitor at the inlet of a kettle liquid pump is 10.5g/min, and the injection amount of the polymerization inhibitor at the material inlet of a reboiler at the tower bottom is 1.5 g/min.

(III) advantageous effects

The method for reducing the solvent autopolymer of the butadiene device provided by the invention has the advantages that the synergistic polymerization inhibitor is simultaneously injected into a reboiler material inlet pipeline and a kettle liquid pump inlet at the bottom of the solvent analysis tower, so that the polymerization inhibitor can enter the solvent in an all-around dead angle-free manner, various oxygen-containing compounds in the acetonitrile solvent can be effectively inhibited from undergoing a self-polymerization reaction at the bottom of the tower and in a reboiler pipe side to form impurities such as dimers, polymers and the like, the purposes of purifying the solvent and prolonging the service cycle of the reboiler are achieved, and the safe, stable, long-cycle, full-load and high-.

The invention can inhibit the blockage of the reboiler serving as a dead angle to form the autopolymer in the tube side, and the cleaning period of the reboiler is prolonged from once in half a year to once in one year and half a year, thereby improving the running quality of the device and reducing the parking loss by about 100 ten thousand yuan.

Drawings

FIG. 1 is a schematic diagram of a method for reducing solvent autopolymer in a butadiene plant according to an embodiment of the invention.

Detailed Description

In order to make the objects, contents and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.

This example presents a method for reducing solvent autopolymers in a butadiene plant, which is directed to a butadiene plant as shown in FIG. 1. Wherein, the mixed material of the crude butadiene and the acetonitrile sent from the extractive distillation tower enters the desorption tower T-102 from the feeding plate. The crude butadiene is evaporated from the top of the desorption tower T-102 and then enters a second extraction tower through a pipeline; the lower part of the T-102 tower is provided with a carbon-four alkyne enrichment area, gas-phase alkyne-containing materials are extracted from a side line in the area, and a part of the alkyne-containing materials is used as a heat source of the extractive distillation tower and then is sent to the alkyne removing tower. The other part is controlled by flow, and enters together with the material which is used as the heat source of the extraction and rectification tower and has recovered heat after being mixed at the inlet of the alkyne removing tower through a bypass; acetonitrile and water which are obtained from the bottom of the T-102 tower and do not contain hydrocarbon are added with a synergistic polymerization inhibitor through an inlet of a kettle pump P-105 and enter an acetonitrile circulating system after being pressurized. Wherein, two reboilers E-108A and E-108B which take 1.0MPa steam as a heat source are arranged at the bottom of the desorption tower T-102.

To prevent the extractive distillation column from forming an autopolymer, the method of this example employs two approaches to reduce butadiene plant solvent autopolymers, including:

1. At the inlet 1 of the stripping column liquid pump P105, a synergistic polymerization inhibitor was injected, and this polymerization inhibitor was circulated in the system together with the solvent. When the production load of the device is 20T/h, the operating pressure of the desorption tower T-102 is 0.43MPa, the temperature of the tower kettle is controlled between 139 ℃ and 143 ℃, and the adding amount of the polymerization inhibitor is 10.5 g/min.

2. Two synergistic polymerization inhibitor injection lines are added at material inlets 2 and 3 of reboilers E-108A and E-108B at the bottoms of the desorption tower, so that the polymerization inhibitor can inhibit self-polymerization of materials in the reboilers in an all-around and dead-angle-free manner. When the production load of the device is 20T/h, the operating pressure of the desorption tower T-102 is 0.43MPa, the temperature of the tower kettle is controlled between 139 ℃ and 143 ℃, and the injection amount of the polymerization inhibitor is 1.5 g/min.

When only the first means is adopted, after two weeks of operation, the content of the dimer in the solvent acetonitrile is sampled and analyzed to be 0.265% (the design index is less than 1%), which shows that the polymerization inhibition effect can be achieved, and the operation period of the reboilers E-108A and E-108B is 6 months.

When the two measures are adopted simultaneously, after the operation is carried out for two weeks, the content of the dimer in the solvent acetonitrile is sampled and analyzed to be 0.147 percent, thereby showing that the two measures are adopted simultaneously to achieve better polymerization inhibition effect, and the operation period of the reboilers E-108A and E-108B is 18 months.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.