JP5008237B2 - (Meth) acrylic acid and / or its ester transfer pipe installation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of attaching a bypass pipe in a (meth) acrylic acid and / or ester transfer pipe facility, and more specifically, when the bypass pipe is attached to a main pipe, the bypass pipe is transferred (meta The present invention relates to a method for attaching a bypass pipe which is prevented from being blocked by acrylic acid and / or its ester .
[0002]
[Prior art and problems]
Conventionally, in a transfer piping facility for easily polymerizable compounds, a flow meter, a control valve, and the like are incorporated in the middle of the main piping.
At this flow meter or control valve part, polymerization of the polymerizable compound occurs, or a polymerization inhibitor contained in the polymerizable compound is deposited to block these devices. Was inevitable.
[0003]
In order to enable continuous operation without discontinuing the production plant for easily polymerizable compounds even during disassembly and cleaning of these devices, a bypass pipe is attached to the main piping across devices such as flow meters and control valves. Things have been done.
Conventionally, this bypass pipe has been branched and attached to the same horizontal position or a lower position with respect to the main pipe.
While the easily polymerizable compound is passing through the main pipe, solid substances of the easily polymerizable compound may gradually accumulate and adhere to the same horizontal or lower position of the bypass pipe and block the inside of the bypass pipe. There was a drawback that the original purpose of attaching the bypass pipe could not be achieved.
[0004]
[Means for solving the problems]
The present invention provides an attachment method of a bypass pipe in a transfer pipe facility for (meth) acrylic acid and / or its ester , and provides an attachment method of the bypass pipe that prevents blockage due to generation of a polymer in the bypass pipe. To do. That is, the gist of the present invention is as follows.
(1) (meth) In the transfer plumbing acrylic acid and / or esters thereof, when additionally provided a bypass pipe to the main pipe is provided at least a portion rises above the main pipe position of the bypass pipe At least one of the branching part or the connecting part of the bypass pipe is a method for attaching the bypass pipe, wherein the slope angle α rises from 3 to 90 ° above the main pipe .
(2) The bypass pipe attaching method according to (1) above, wherein at least a part of the bypass pipe is provided at a position rising above a flow meter or a control valve incorporated in the middle of the main pipe. .
(3) The bypass pipe attachment method according to (2) above, wherein a bypass pipe is provided across the flow meter or the control valve.
(4) The above-described (1) to (1), wherein one of the bypass pipes is branched from the same height position as the main pipe, and a closing valve is incorporated in a portion of the bypass pipe located at the same height. This is a method of attaching the bypass pipe of 3).
[0005]
DETAILED DESCRIPTION OF THE INVENTION
A method for attaching a bypass pipe in a transfer piping facility for easily polymerizable compounds of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view of a process flow for producing acrylic acid, which is an easily polymerizable compound, FIGS. 2 to 6 are schematic views of each method for attaching a bypass pipe of the present invention, and FIG. 7 is an attachment of each conventional bypass pipe. FIG.
[0006]
First, the outline of the process flow for producing the acrylic acid of FIG. 1 will be described.
A is an acrylic acid collection tower, and acrylic acid-containing reaction gas is supplied from the acrylic acid-containing reaction gas supply line 1 to the acrylic acid collection tower A.
B is a distillation column, and an acrylic acid aqueous solution is supplied to the distillation column B through the acrylic acid aqueous solution extraction line 2 from the bottom of the acrylic acid collecting column A.
C is a high-boiling separation column, and crude acrylic acid is supplied to the high-boiling separation column C from the bottom of the distillation column B via the crude acrylic acid extraction line 3.
The crude acrylic acid supplied to the high-boiling separation column C is purified to become high-purity purified acrylic acid, and is extracted from the top of the column by purified acrylic acid extraction lines 5 and 6.
D is a high boiling cracking reactor, and a high boiling point substance is supplied to the high boiling cracking reactor D from the bottom of the high boiling separation tower C via the high boiling separation tower extraction line 7.
High boilers are separated and removed from the bottom of the high boiling cracking reactor D via the high boiling cracking reactor discharge line 8.
In addition, 9 is an acrylic acid collection water supply line, 10 is a reflux line, and 11 is a polymerization inhibitor supply line.
[0007]
Next, a method for attaching a bypass pipe according to the present invention will be described with reference to FIGS.
In FIG. 2, 13 is a horizontal main pipe, and the main pipe 13 may be either a line connecting the devices shown in FIG. 1 or a line sent out of the system. A high-purity acrylic acid extraction line 6 extracted from the top of the boiling separation column C or an extraction line 8 of the high-boiling decomposition reactor D may be used.
A drain pipe 15 is connected in the middle of the horizontal main pipe 13 and a control valve CV is incorporated.
Reference numeral 14 denotes a bypass pipe. The bypass pipe 14 is branched from a main pipe 13 horizontally arranged, rises upward at a gradient angle α, and is connected to the main pipe 13 again at a gradient angle α across the control valve CV. This is a bypass pipe for the control valve CV.
[0008]
In the example of FIG. 3, the bypass pipe 14 is a control valve that is a pipe that branches in the horizontal direction via a stop valve SV at a distance L from the branch portion of the main pipe 13 and is connected to the main pipe 13 at a gradient angle α again. This is a bypass pipe for CV.
The main pipe 13 is bent downward from the branch part of the bypass pipe 14 and then horizontally piped. A drain pipe 15 is connected to the horizontal pipe part and a control valve CV incorporated in the pipe part is provided. This is an example in which it is connected to the bypass pipe 14 after being interposed.
[0009]
In the example of FIG. 4, the bypass pipe 14 is branched from the main pipe 13, rises upward at a gradient angle α, is then horizontally piped, and again the main pipe 13 is interposed via a shut-off valve SV incorporated in the horizontal pipe portion. This is a bypass pipe for the flow meter FM with a pipe connected to the pipe.
The main pipe 13 is an example in which the main pipe 13 is piped horizontally from the branch portion of the bypass pipe 14 and then bent vertically upward, and is connected to the bypass pipe 14 after interposing a flow meter FM incorporated in the vertical pipe portion. is there. Reference numeral 15 denotes a drain pipe connected to the main pipe 13.
[0010]
In the example of FIG. 5, the flow meter FM and the control valve CV are incorporated in the middle of the main pipe 13, and the bypass tube 14-1 for the flow meter FM and the adjustment are provided in each of the flow meter FM and the control valve CV. This is an example in which a bypass pipe 14-2 for the valve CV is provided.
Then, the bypass pipe 14-2 for the control valve CV is a pipe branched in the horizontal direction via a stop valve SV at a distance L from the branch portion of the main pipe 13 and again connected to the main pipe 13 at a gradient angle α. It is. Reference numeral 15 denotes a drain pipe connected to the main pipe 13.
[0011]
The example of FIG. 6 is also an example in which the flow meter FM and the control valve CV are incorporated in the middle of the main pipe 13, and the bypass pipe 14 is provided across the flow meter FM and the control valve CV. Reference numeral 15 denotes a drain pipe connected to the main pipe 13.
In each of the above examples, an orifice type flow meter can be used instead of the control valve CV.
[0012]
The slope angle α between the bypass pipe 14 rising from the main pipe 13 and the main pipe 13 may be set to 3 to 90 ° on the acute angle side. If the gradient angle α deviates from the specified value, the effect of the present invention may not be sufficiently obtained.
Further, when the bypass pipe 14 is provided by branching horizontally from the main pipe 13 with the stop valve SV interposed, the distance L from the branch portion of the main pipe 13 to the stop valve SV is set within 50 cm, preferably within 30 cm. Good.
When this distance is short, circulation occurs in the branching part due to the flow of liquid in the main pipe and the temperature difference, and the liquid is updated. However, when the distance L of the branching part is long, the liquid stays for a long time and is not updated. Since this is in a state, polymerization is likely to occur and clogging tends to occur, which is not preferred, so the L should be within 50 cm.
[0013]
FIG. 7 shows an example of a conventional bypass pipe installation method.
In FIG. 7, reference numeral 13 denotes a main pipe that is horizontally piped. A drain pipe 15 is connected to the main pipe 13 and a control valve CV is incorporated therein.
Reference numeral 14 denotes a bypass pipe which branches downward from the main pipe 13 on the upstream side of the control valve CV as shown by a solid line, is further bent horizontally, and is adjusted via a shut-off valve SV incorporated in the horizontal portion. It is the prior art example of the attachment method used as the bypass pipe for the control valve CV reconnected to the main piping 13 across the valve CV.
In addition, as shown by a dotted line, the conventional example of the attachment method by which the bypass pipe 14 was piped horizontally and used as the bypass pipe for the control valve CV is also seen.
[0014]
The easily polymerizable compound in the present invention means a compound that is easily polymerized to form a polymer upon handling such as reaction or distillation, and typical examples thereof include (meth) acrylic acid and esters thereof, such as Mention may be made of methyl, ethyl, butyl, isobutyl, tertiary butyl, 2-ethylhexyl, 2-hydroxyethyl, 2-hydroxypropyl, methoxyethyl and the like.
[0015]
【Example】
Example 1
The example of an acrylic acid manufacturing process is shown.
In FIG. 5, the bypass pipe 14-1 for the flow meter FM is branched from the horizontal portion of the main pipe 13 on the inflow side of the flow meter FM and has a rising angle of α = 90 ° and an intervening stop valve SV. The main pipe 13 on the outflow side of the flow meter FM was connected at a right angle.
On the other hand, the bypass pipe 14-2 for the control valve CV branches horizontally from the horizontal part of the main pipe 13 on the inflow side of the control valve CV, and a closing valve SV is interposed in the horizontal part of L = 30 cm from the branch part. Subsequently, the bypass pipe 14-2 was dropped and connected to the horizontal portion of the main pipe 13 on the outflow side of the control valve CV at a gradient angle α = 90 °.
The extraction composition of the high boiling separator C was 60% by weight of acrylic acid, 25% by weight of acrylic acid dimer, 8% by weight of maleic anhydride, and the temperature was 80 ° C.
After the operation for 3 months, the flowmeter FM was clogged. Therefore, the operation was continued through the extracted liquid through the bypass pipe 14-1 during the replacement work. After the flowmeter FM was restored, the operation could be continued for a total of 6 months.
[0016]
Example 2
The example of the manufacturing process of butyl acrylate is shown.
In FIG. 3, the shut-off valve SV incorporated in the horizontal part of the bypass pipe 14 is installed 30 cm from the branch part of the bypass pipe 14, and then the bypass pipe 14 is perpendicular to the main pipe 13 (gradient angle α = 90 °).
The composition extracted from the high boiling decomposition reactor D is 7% by weight of acrylic acid (excluding acrylic acid dimer), 68% by weight of butyl butoxypropionate, 11% by weight of butyl acrylate, and others (polymer, inhibitor, etc.) The weight was 14% by weight and the temperature was 140 ° C.
After 5 months of operation, the control valve CV was clogged, so that the operation was continued through the bypass pipe 14 during the replacement operation. After the control valve CV was restored, the operation could be continued for a total of 10 months.
[0017]
Comparative Example 1
As shown by the solid line in FIG. 7, the bypass pipe 14 for the control valve CV was attached below the horizontal of the main pipe 13, and the operation was performed in the same manner as in Example 1.
After three months of operation, the control valve CV was clogged. Therefore, during the replacement work, when the operation was conducted through the bypass pipe 14, the bypass pipe 14 was clogged and the operation had to be stopped. There wasn't.
[0018]
【Effect of the invention】
If the method for attaching a bypass pipe of the present invention is used, in piping equipment for transferring easily polymerizable substances such as (meth) acrylic acid, occurrence of clogging in the bypass pipe is effectively prevented and the pipe is installed in the transfer piping equipment. Since the operation can be continued even when the devices such as the flowmeter and the control valve are closed, the production volume is prevented from decreasing and the industrial production is extremely profitable.
[Brief description of the drawings]
FIG. 1 is a schematic view of a process flow for producing acrylic acid which is an easily polymerizable compound.
FIG. 2 is a schematic diagram of Example 1 of a method for attaching a bypass pipe according to the present invention.
FIG. 3 is a schematic diagram of Example 2 of the method for attaching a bypass pipe of the present invention.
FIG. 4 is a schematic diagram of Example 3 of a method for attaching a bypass pipe according to the present invention.
FIG. 5 is a schematic diagram of Example 4 of the method for attaching a bypass pipe according to the present invention.
FIG. 6 is a schematic diagram of Example 5 of the method for attaching a bypass pipe of the present invention.
FIG. 7 is a schematic view of a conventional example of a conventional bypass pipe attaching method.
[Explanation of symbols]
A ... Acrylic acid collection tower B ... Distillation tower C ... High boiling separation tower D ... High boiling decomposition reactor FM ... Flow meter CV ... Control valve 13 ... Main piping 14, 14-1, 14-2 ... Bypass piping 15 ... Drain pipe α ... Rise angle of the bypass pipe

Claims (2)

(Meth) acrylic acid and / or its ester transfer piping equipment, a method of attaching a bypass pipe to the main pipe ,
The bypass pipe is provided with a closing valve,
At least one of the branch part or the connection part of the bypass pipe rises above the main pipe with a gradient angle α of 3 to 90 ° ,
When there is the branch part or the connection part that does not satisfy the condition, the shutoff valve is provided in the bypass pipe at a distance within 50 cm from the branch part or the connection part . Attached method.   The bypass pipe installation method according to claim 1, wherein a bypass pipe is provided across the flow meter or the control valve.

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