A preparation method of 1,4-butynediol
By adjusting the reaction temperature and exhaust exhaust gas volume and controlling the acetylene content in the exhaust gas and circulating gas, the problem of acetylene concentration drop in the preparation of 1,4-butyne glycol by acetylene alkaldehyde is solved, and the efficient utilization and environmental protection of acetylene are achieved.
Patent Information
- Application Number
- CN202310831404.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-07
- Publication Date
- 2025-08-29
- Estimated Expiration
- 2043-07-07
AI Technical Summary
In the prior art, during the preparation of 1,4-butynylene glycol by alkynaldehyde, the decrease in acetylene concentration leads to waste of resources and environmental pollution, and the outer displacement of acetylene is high, resulting in incomplete combustion and high operating costs.
By adjusting the reaction temperature and/or the emission of the exhaust exhaust gas, the acetylene content in the exhaust gas and circulating gas is controlled to keep it within an appropriate range, and the circulating gas returns to the reaction system to reduce exhaust gas emissions and improve acetylene utilization.
While maintaining the reaction efficiency, the exhaust emissions are reduced, the utilization rate of acetylene is improved, the emissions of acetylene are reduced, and environmental pollution and resource waste are avoided.
Smart Images
Figure CN116854563B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to 1,4-butynediol, and in particular to a preparation method of 1,4-butynediol capable of reducing acetylene emissions. Background Art
[0002] The existing technology generally uses the acetylene-aldehyde method to prepare 1,4-butynediol (BYD). For example, acetylene and formaldehyde are used as the reaction raw materials in the presence of a copper-based catalyst to prepare 1,4-butynediol through a continuous process. During the reaction, a portion of the gas containing acetylene in the system (recycled gas) is discharged, mixed with new acetylene raw materials and continued to be used in the reaction, while the remaining gas is discharged (tail gas). However, since the new acetylene raw materials will introduce inert gases (gases that do not participate in the reaction) such as nitrogen, propadiene, and carbon dioxide, inert carbon dioxide will also be generated during the reaction (for example, using sodium carbonate to adjust the pH), and the recycling of the recycle gas will lead to the accumulation of inert gases. These factors will cause the acetylene concentration in the gas after the reaction to continue to decrease.
[0003] To ensure reaction efficiency, the acetylene concentration in the post-reaction gas must be controlled within a certain range. Therefore, the inert gas must be continuously exhausted, and the acetylene is also discharged along with it. If the acetylene content in the exhaust gas is high, it will waste resources and increase unit consumption. Furthermore, the exhausted acetylene is often flared or incinerated, which can lead to incomplete combustion, environmental pollution, acetylene waste, and high operating costs. Therefore, it is important to reduce acetylene emissions while ensuring reaction efficiency. Summary of the Invention
[0004] To overcome at least one of the above-mentioned drawbacks of the prior art, one embodiment of the present invention provides a method for preparing 1,4-butynediol, comprising preparing 1,4-butynediol by an acetylene-aldehyde process, wherein the raw material of the acetylene-aldehyde process comprises acetylene; the gas discharged from the acetylene-aldehyde process reaction system comprises a circulating gas and an exhaust gas, and the circulating gas is returned to the reaction system to continue participating in the reaction as a raw material;
[0005] The acetylene content in the tail gas and the circulating gas is controlled by adjusting the reaction temperature and / or the emission amount of the tail gas during the reaction.
[0006] The preparation method of 1,4-butynediol according to one embodiment of the present invention can maintain the acetylene content in tail gas and circulating gas within a certain range, making the circulating gas suitable for returning to the reaction system for reuse, thereby reducing tail gas emissions while maintaining reaction efficiency. The reduction in tail gas emissions allows more acetylene-containing gas to be reused in the form of circulating gas, thereby improving the utilization rate of acetylene. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The accompanying drawings are only used to illustrate specific embodiments and are not to be considered as limiting the present invention.
[0008] Figure 1 The present invention is a partial structural diagram of a device for preparing 1,4-butynediol according to an embodiment of the present invention. DETAILED DESCRIPTION
[0009] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention is capable of various variations in different embodiments without departing from the scope of the present invention, and the descriptions herein are intended to be illustrative rather than limiting.
[0010] One embodiment of the present invention provides a method for preparing 1,4-butynediol, particularly a continuous method for preparing 1,4-butynediol, comprising preparing 1,4-butynediol by an acetylene-aldehyde process, for example, using acetylene and formaldehyde as raw materials to prepare 1,4-butynediol; dividing the gas (including acetylene gas) discharged from the acetylene-aldehyde process reaction system into two parts, one part of which is returned to the reaction system in the form of circulating gas (circulating acetylene) to continue participating in the reaction as a raw material; and the other part is discharged as tail gas (exhaust tail gas, referred to as "tail gas");
[0011] The acetylene content in the tail gas and the circulating gas (or the acetylene content in the gas discharged from the reaction system) is controlled by adjusting the reaction temperature and / or the emission rate of the tail gas during the reaction.
[0012] In one embodiment, the acetylene content in the recycle gas is the same as the acetylene content in the tail gas.
[0013] In one embodiment, the total amount of gas discharged from the reaction system is maintained at a substantially constant value, that is, the amount of tail gas emissions is reduced and the amount of recycle gas is increased.
[0014] The method for preparing 1,4-butynediol according to one embodiment of the present invention controls the reaction temperature and / or the amount of exhaust gas discharged, thereby maintaining the acetylene content in the exhaust gas and recycle gas within a certain range. This allows the recycle gas to be returned to the reaction unit for reuse as a reaction raw material, thereby maintaining reaction efficiency while allowing more acetylene-containing gas to be used as recycle gas. This reduces exhaust gas emissions, improves acetylene utilization, and reduces acetylene emissions, thereby avoiding or reducing the occurrence of subsequent problems caused by acetylene emissions. Specifically, the raw acetylene contains impurities such as propyne, propadiene, carbon dioxide, nitrogen, and other inert gases. Furthermore, the use of sodium carbonate / sodium hydroxide buffer to adjust the pH during the reaction also produces carbon dioxide. The presence of these gases causes impurities in the post-reaction gas, which reduces the acetylene concentration (or content) in the post-reaction gas materials (recycle gas and exhaust gas). By adjusting the exhaust gas discharge amount and / or the reaction temperature during the recycling process, the acetylene consumption during the reaction can be changed, thereby maintaining the acetylene content in the recycle gas and exhaust gas.
[0015] In one embodiment, a set value for the acetylene content in the tail gas is provided; when the acetylene content in the tail gas is higher than the set value, the tail gas emission is reduced or the reaction temperature is increased to reduce the acetylene content in the tail gas; when the acetylene content in the tail gas is lower than the set value, the tail gas emission is increased or the reaction temperature is lowered to increase the acetylene content in the tail gas.
[0016] In one embodiment, when the acetylene content in the tail gas is higher than a set value, the emission of the tail gas is adjusted first; when the acetylene content in the tail gas is lower than a set value, the reaction temperature is adjusted first.
[0017] In one embodiment, when the acetylene content in the tail gas is higher than a set value, the exhaust gas emission is reduced to reduce the acetylene content in the tail gas; if the exhaust gas emission reaches the lower limit of the adjustable range and the acetylene content in the tail gas is still higher than the set value, the acetylene content in the tail gas is further reduced by increasing the reaction temperature.
[0018] In one embodiment, when the acetylene content in the tail gas is lower than a set value, the reaction temperature is lowered to increase the acetylene content in the tail gas; if the acetylene content in the tail gas is still lower than the set value when the reaction temperature reaches the lower limit of the adjustable range, the acetylene content in the tail gas is increased by increasing the tail gas emission rate.
[0019] In one embodiment, the set value of the acetylene content in the tail gas can be limited according to the reaction system, equipment, actual needs, etc. For example, the set value of the acetylene content in the tail gas can be 50-60 vol%.
[0020] In one embodiment, the acetylene content in the tail gas is detected by an online acetylene concentration detector; the online acetylene concentration detector may be an existing device.
[0021] In one embodiment, the acetylene content in the tail gas can be detected by near infrared spectroscopy.
[0022] In one embodiment, the measurement interval of the acetylene content in the tail gas is no more than 10 minutes to ensure timely feedback; further, it can be 1 second to 10 minutes, preferably no more than 1 minute, for example, 2 seconds, 5 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 2 minutes, 5 minutes, 6 minutes, and 8 minutes; the measurement error can be less than 0.5%, preferably less than 0.1%.
[0023] In one embodiment, the adjustment range of the reaction temperature T (unit: ° C.) is determined by the reaction load F (%) and the catalyst operation time Th (unit: day), and the calculation formula is:
[0024] 90+(F-100)×0.1+(Th-90)×0.08≤T≤95+(F-100)×0.08+(Th-90)×0.05
[0025] The reaction load F ranges from 30 to 100, such as 40, 50, 60, 70, 80, and 90. The value of F is determined based on the amount of formaldehyde. For example, the full formaldehyde feed load is 18.8 t / h, and the minimum feed load is 6 t / h. Here, F = real-time formaldehyde feed flow rate / 18.8 × 100. The operation time Th ranges from 0 to 120, such as 1, 2, 10, 20, 30, 50, 60, 80, and 100. The above formula only represents the relationship between the numerical values of F, T, and Th, and does not include the corresponding relationship between units.
[0026] In one embodiment, the adjustment range of the reaction temperature T is 75.8-96.5°C. When the reaction load F=30 and the operating time Th=0, the lowest reaction temperature is 75.8°C; when the reaction load F=100 and the operating time Th=120, the highest reaction temperature is 96.5°C.
[0027] In one embodiment, the reaction load F=100, Th=120, and the reaction temperature T is adjusted in the range of 92.4-96.5°C.
[0028] In one embodiment, the acetylene content in the tail gas is adjusted in the range of 40-64 vol%, preferably 53-58 vol%, such as 45 vol%, 50 vol%, 55 vol%, 56 vol%, and 60 vol%.
[0029] In one embodiment, the adjustable range of tail gas emissions at 100% load can be 20-200 kg / h, such as 30 kg / h, 50 kg / h, 60 kg / h, 80 kg / h, 100 kg / h, 120 kg / h, 140 kg / h, and 150 kg / h; the adjustable range of tail gas emissions at 80% load can be 20-120 kg / h, such as 30 kg / h, 50 kg / h, 60 kg / h, 80 kg / h, 100 kg / h, and 110 kg / h; the adjustable range of tail gas emissions at 60% load can be 20-90 kg / h, such as 30 kg / h, 50 kg / h, 60 kg / h, and 80 kg / h; the adjustable range of tail gas emissions at 40% load can be 20-70 kg / h, such as 30 kg / h, 50 kg / h, and 60 kg / h. The above values are obtained based on the actual operating data of the device.
[0030] In one embodiment, a control relationship between the reaction temperature and / or the amount of exhaust gas discharged and the acetylene content in the exhaust gas is achieved through a logic control module to achieve automated operation of the regulation.
[0031] In one embodiment, a logic control module can be added to the DCS system to cascade the exhaust gas emission volume and the acetylene content in the exhaust gas to achieve automatic control of exhaust gas emissions and reduce fluctuations; the control logic is to reduce the exhaust gas emission volume when the acetylene content in the exhaust gas is high, and to increase the exhaust gas emission volume when the acetylene content in the exhaust gas is low.
[0032] In one embodiment, cascade control of the acetylene content in the tail gas and the reaction temperature can be achieved through a logic control module. The reaction temperature is controlled according to the acetylene content in the tail gas. The control logic is that when the acetylene content in the tail gas is high, the reaction temperature is increased, and when the acetylene content in the tail gas is low, the reaction temperature is reduced.
[0033] In one embodiment, a selection control module, which serves as a selection controller, may be added. The judgment logic is based on the difference between the current acetylene content in the exhaust gas and a set value. If the difference is greater than 0 (high acetylene content in the exhaust gas), the exhaust gas emissions are reduced according to the above description. If the acetylene content in the exhaust gas is still higher than the set value when the exhaust gas emissions drop to the lowest value of the adjustable range, the reaction temperature is increased within the adjustable temperature range. If the difference is less than 0 (low acetylene content in the exhaust gas), the reaction temperature is lowered until the acetylene content in the exhaust gas reaches the set value according to the above description. If the acetylene content in the exhaust gas is still lower than the set value when the reaction temperature drops to the lowest value of the adjustable temperature range, the exhaust gas emissions are increased.
[0034] In one embodiment, the preparation process of 1,4-butynediol can adopt the existing acetylene aldehyde method, and acetylene and formaldehyde are reacted in the presence of a catalyst. The catalyst can be a copper-based catalyst, such as unsupported basic copper carbonate / basic bismuth carbonate, supported CuO / Mg2SiO3, CuO / Al2O3, etc.
[0035] In one embodiment, the preparation process of 1,4-butynediol includes a process for reacting acetylene with formaldehyde, a process for washing the acetylene, and a process for recycling the recycle gas to the feed port for recycling. The acetylene washing process includes washing the acetylene raw material before it is introduced into the reactor and washing the gas discharged from the reactor (including the recycle gas and the tail gas).
[0036] In one embodiment, the newly added acetylene feedstock and the recycled acetylene can be used as reactants in the acetylene-aldehyde process; the concentration of acetylene in the acetylene feedstock is not less than 60 vol%, preferably 95-100 vol%.
[0037] In one embodiment, the formaldehyde raw material may be an aqueous solution of formaldehyde, wherein the concentration of formaldehyde is 30 to 56 wt %, preferably 40 to 55 wt %.
[0038] In one embodiment, the 1,4-butynediol production device may be an existing device.
[0039] In one embodiment, reference Figure 1 As shown, the preparation device of 1,4-butynediol includes a reactor 10, an online acetylene concentration detector (AIC) 20, a temperature controller (TIC) 30, and a first flow controller (FIC) 41; wherein, the online acetylene concentration detector 20 is used to detect the acetylene content in the exhaust gas; the temperature controller 30 is used to adjust the temperature inside the reactor 10, and the first flow controller 41 is used to adjust the exhaust gas emission.
[0040] In one embodiment, the preparation device of 1,4-butynediol includes a first flow valve 51 and a second flow valve 52, and the first flow valve 51 and the second flow valve 52 are both arranged on the exhaust gas emission pipeline to control the emission of exhaust gas, wherein the adjustment range of the first flow valve 51 can be 0 to 1000 kg / h, for example, 1kg / h, 10kg / h, 100kg / h, 200kg / h, 500kg / h, 800kg / h, which is used to regulate large-scale exhaust gas emissions during the catalyst activation process; the adjustment range of the second flow valve 52 can be 0 to 300 kg / h, for example, 1kg / h, 10kg / h, 20kg / h, 50kg / h, 100kg / h, 150kg / h, 200kg / h, 250kg / h, which is used to regulate exhaust gas emissions during normal reaction.
[0041] In one embodiment, the 1,4-butynediol production apparatus includes a second flow controller 42 disposed on the formaldehyde feed line. Furthermore, a third flow valve 53 is disposed on the formaldehyde feed line. The second flow controller 42 and the third flow valve 53 control the flow of the formaldehyde feed.
[0042] In one embodiment, the online acetylene concentration detector 20 can transmit the detected acetylene content information of the exhaust gas to the control module, and the control module can issue corresponding instructions to the temperature controller 30 and / or the first flow controller 41 according to the acetylene content of the exhaust gas to achieve the regulation of the acetylene content in the exhaust gas. Figure 1 The dotted part represents the corresponding relationship between the signals or instructions between the control module and the corresponding components during the reaction process, and is not an entity structure.
[0043] A method for preparing 1,4-butynediol according to one embodiment of the present invention controls the acetylene content in the tail gas and the circulating gas by adjusting the reaction temperature and / or the emission amount of the exhaust gas, thereby reducing acetylene emissions by more than 20%, improving the utilization rate of acetylene, and reducing environmental pollution caused by acetylene emissions.
[0044] In the preparation method of 1,4-butynediol according to one embodiment of the present invention, as the operating time increases, the activity of the catalyst used in the synthesis reaction of 1,4-butynediol decreases, and the reaction raw materials acetylene and formaldehyde undergo polymerization side reactions, resulting in the optimal reaction temperature varying with the use time and load of the catalyst; when the reaction temperature is too high, the catalyst activity is also high, but the polymerization reaction of acetylene and the disproportionation reaction of formaldehyde increase, and there are too many side reactions, resulting in a low yield; when the reaction temperature is too low, the catalyst activity is poor, and the conversion rate of the raw materials decreases. One embodiment of the present invention can determine a preferred reaction temperature range based on the operating time and load of the catalyst, and further adjust the reaction temperature and tail gas emissions in a timely manner based on the acetylene content in the tail gas, thereby achieving optimal reaction efficiency.
[0045] Adjusting the reaction temperature and / or tail gas emissions by human operation has a hysteresis, and the acetylene content in the tail gas and the exhaust volume of the tail gas fluctuate greatly, with a large variance, and human operation may lead to unnecessary exhaust. A method for preparing 1,4-butynediol according to one embodiment of the present invention controls the reaction temperature and / or exhaust gas emissions by a control module, which can overcome the drawbacks of human operation, reduce the fluctuation of the exhaust gas exhaust volume, and ultimately achieve a reduction in the acetylene exhaust volume in the tail gas. The control module may include a logic control module, or include a logic control module and a selection control module.
[0046] The following further describes the preparation method of 1,4-butynediol according to one embodiment of the present invention with reference to the accompanying drawings and specific examples. Unless otherwise specified, all raw materials used are commercially available.
[0047] Example 1
[0048] Fresh raw acetylene and recycled acetylene are pressurized by a compressor and passed into a scrubber. After organic matter is scrubbed from the recycled acetylene, the acetylene enters reactor 10, where it reacts with formaldehyde over a catalyst to produce 1,4-butynediol. The remaining gas is discharged from the top of reactor 10 and, after passing through the outlet scrubber, a portion enters the compressor inlet as recycled acetylene (recycle gas). The remaining gas (tail gas) passes through the tail gas scrubber and is flared. The acetylene content in the tail gas and the recycled gas is the same.
[0049] Among them, under 100% load, when the catalyst is operated for 10 days, the feed rate of formaldehyde solution (formaldehyde content is 50.5wt%) is 20t / h, the feed rate of new acetylene raw material (acetylene content is 99vol%) is 4458t / h, and after entering the reactor 10, acetylene and formaldehyde react in the presence of copper bismuth catalyst to produce 1,4-butynediol, and the flow rate of circulating acetylene is approximately 5813t / h. During the reaction, the acetylene content and exhaust gas emissions are cascade controlled by the control module, and the control logic is as described above. The set value of the acetylene content in the exhaust gas is 55vol%, the reaction temperature is maintained at 90°C, and the adjustable range of the exhaust gas emissions is 20-200kg / h. During the process, the acetylene content of the exhaust gas is controlled at 53-58vol% (average value is 55vol%), and the average exhaust gas discharge is 90kg / h.
[0050] Example 2
[0051] This example uses the same raw materials and process as Example 1 to prepare 1,4-butynediol, with the only difference being that during the reaction, the acetylene content, the exhaust gas emissions, and the reaction temperature are cascade-controlled by a control module, and the control logic is as described above; the reaction temperature is controlled by the acetylene content, and the adjustment range of the reaction temperature is 89.5 to 91°C (the average value is 90.5°C); the set value of the acetylene content in the exhaust gas is 55 vol%, the adjustable range of the exhaust gas emissions is 20 to 200 kg / h, and the adjustment range of the acetylene content in the exhaust gas is 54 to 56 vol% (the average value is 55 vol%); and the average exhaust gas discharge during the process is 80 kg / h.
[0052] Example 3
[0053] This example uses the same raw materials and process as Example 1 to prepare 1,4-butynediol, with the only difference being that during the reaction, the acetylene content and reaction temperature are controlled in cascade, the set value for the acetylene content in the tail gas is 55 vol%, the reaction temperature is gradually adjusted to 91°C, and the adjustment range of the reaction temperature is 90-91°C. When the reaction temperature is adjusted to the end of the adjustment range, the tail gas emission rate is manually adjusted to adjust the acetylene content in the tail gas.
[0054] Due to the manual adjustment of the exhaust gas emission volume during the process, the exhaust gas emission volume fluctuates within the range of 60 to 120 kg / h, with poor stability. The average exhaust gas emission volume is 95 kg / h.
[0055] Comparative Example 1
[0056] This example uses the same raw materials and process as Example 1 to prepare 1,4-butynediol, except that: no control module is used, and the acetylene content of the tail gas during the reaction is manually adjusted by personnel, and no temperature adjustment is performed, and the reaction temperature is maintained at 90°C; wherein, the acetylene content in the tail gas fluctuates between 53 and 58 vol%, and the acetylene emissions in the tail gas fluctuate between 90 and 120 kg / h; the average acetylene content in the tail gas is maintained at 55 vol%, and the average tail gas emissions are 105 kg / h.
[0057] From the description of the embodiments and comparative examples of the present invention, it can be seen that in Example 1, the acetylene content in the exhaust gas is adjusted by cascade controlling the acetylene content and the exhaust gas emissions through a control module, so that the acetylene content in the exhaust gas is controlled at about 55 vol%, and the average exhaust gas emission volume is 90 kg / h; compared with Comparative Example 1, the exhaust gas emission volume is greatly reduced, thereby reducing the acetylene emissions.
[0058] Based on Example 1, Example 2 further adds cascade control of acetylene content and reaction temperature. By adjusting the reaction temperature and exhaust gas emissions, the exhaust gas emissions are further reduced compared to Example 1 (the average value is 80 kg / h).
[0059] Compared with Example 1, Example 3 adopts cascade control of acetylene content and reaction temperature, and the exhaust gas emission is manually adjusted. The manual adjustment causes large fluctuations in the exhaust gas emission and poor stability. The exhaust gas emission is increased compared with Example 1 (the average value is 95 kg / h), but is still lower than that of Comparative Example 1 (the average value is 105 kg / h).
[0060] Unless otherwise defined, the terms used in the present invention have the same meanings as those commonly understood by those skilled in the art.
[0061] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above-mentioned embodiments, but is only limited by the claims.
Claims
1. A method for preparing 1,4-butynediol, comprising preparing 1,4-butynediol by an acetylene-aldehyde process, wherein the raw material of the acetylene-aldehyde process comprises acetylene; the gas discharged from the acetylene-aldehyde process reaction system comprises a circulating gas and an exhaust gas, and the circulating gas is returned to the reaction system as a raw material to continue participating in the reaction; in, During the reaction process, the acetylene content in the tail gas and the circulating gas is controlled by adjusting the reaction temperature and / or the emission amount of the tail gas, and the control relationship between the reaction temperature and / or the emission amount of the tail gas and the acetylene content in the tail gas is achieved through a control module; providing a set value for the acetylene content in the tail gas, and when the acetylene content in the tail gas is higher than the set value, reducing the exhaust gas emission; and thereafter, if the exhaust gas emission reaches a lower limit of an adjustment range and the acetylene content in the tail gas is still higher than the set value, increasing the reaction temperature; When the acetylene content in the tail gas is lower than the set value, the reaction temperature is lowered; thereafter, if the acetylene content in the tail gas is still lower than the set value when the reaction temperature reaches the lower limit of the adjustment range, the emission of the tail gas is increased; The set value is 50-60 vol%; the adjustment range of the reaction temperature T is determined by the following formula: 90+(F-100)×0.1+(Th-90)×0.08≤T≤95+(F-100)×0.08+(Th-90)×0.05 F is the reaction load, and the value of F is 30~100; Th is the operating time, and the value of Th is 0~120, and the unit of T is ℃.
2. The method according to claim 1, wherein The reaction temperature is 80-95°C.
3. The method according to claim 1, wherein The measurement interval of the acetylene content in the tail gas is no more than 10 minutes; and / or, The acetylene content in the tail gas is measured by an online acetylene concentration detector.
4. The method according to claim 1, wherein The acetylene content in the circulating gas is the same as the acetylene content in the tail gas.
5. The method according to claim 1, wherein The raw materials of the acetylene-aldehyde method include acetylene and formaldehyde, and acetylene and formaldehyde react under the action of a catalyst, and the catalyst is a copper-based catalyst.