JP5388199B2 - Method and apparatus for producing carbon monoxide gas - Google Patents

Description

  The present invention relates to a method and apparatus suitable for producing carbon monoxide gas by a formic acid dehydration reaction using an aqueous sulfuric acid solution.

It is well known that carbon monoxide gas (CO) and water (H ₂ O) are produced by the dehydration reaction of formic acid (HCOOH) introduced into an aqueous solution of sulfuric acid (H ₂ SO ₄ ). Is represented by:
HCOOH → CO + H ₂ O

  Conventionally, a carbon monoxide gas is produced by a batch method by heating a reactor charged with formic acid and a sulfuric acid aqueous solution. In this case, the aqueous sulfuric acid solution is gradually diluted with water produced by the dehydration reaction, and the reaction rate is lowered, so that productivity is lowered. Therefore, the diluted sulfuric acid aqueous solution is discarded after neutralizing with alkali. In addition, residual formic acid that has not been used in the dehydration reaction is a deleterious substance, and treatment for preventing an increase in chemical oxygen demand (COD) is required when the aqueous sulfuric acid solution is discarded.

  In order to eliminate the waste of sulfuric acid aqueous solution, carbon monoxide gas and water are continuously generated by dehydration reaction by continuously introducing formic acid into the heated sulfuric acid aqueous solution in the reactor. A method has been proposed in which an aqueous sulfuric acid solution diluted with prepared water is concentrated and reused. In this conventional continuous production method, the sulfuric acid aqueous solution diluted with the water produced by the dehydration reaction is discharged from the reactor together with the produced carbon monoxide gas, and then separated from the carbon monoxide gas. Then, it is concentrated by heating under reduced pressure in a concentration vessel, and then returned to the reactor (see Patent Document 1).

JP-A-6-247707

  In the conventional method of continuously producing carbon monoxide gas, in order to use all formic acid introduced into the sulfuric acid aqueous solution in the reactor for the dehydration reaction, it is necessary to limit the introduction rate of formic acid into the sulfuric acid aqueous solution. is there. However, if the introduction rate of formic acid is limited, the productivity of carbon monoxide gas decreases. Therefore, when carbon monoxide gas is produced industrially, the formic acid introduction rate becomes higher than the decomposition rate of formic acid, and residual formic acid that is not subjected to dehydration reaction is generated. Then, the residual formic acid flows out of the reaction system together with the carbon monoxide gas as a vapor, and there is a problem that recovery becomes difficult. Furthermore, if the reaction temperature is increased to improve productivity, the amount of evaporation of residual formic acid increases. An object of this invention is to provide the manufacturing method and manufacturing apparatus of carbon monoxide gas which can solve the subject of such a prior art.

The method of the present invention is a process for producing carbon monoxide gas comprising a step of generating carbon monoxide gas and water by dehydration reaction of formic acid continuously introduced into a heated reaction solution containing at least an aqueous sulfuric acid solution in the reactor. In the method, water vapor generated by heating the reaction liquid in the reactor and residual formic acid together with the generated carbon monoxide gas in the azeotropic apparatus disposed in the outflow path of the carbon monoxide gas from the reactor And the boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic apparatus, and is substantially located downstream of the boiling region of the azeotropic mixture in the flow of carbon monoxide gas. From the step of heating the azeotropic apparatus, the step of introducing water into the azeotropic apparatus, and the azeotropic apparatus so as to maintain a single boiling region of water in which no formic acid is mixed. Monoacid flowing out with water vapor And a step of isolating the carbon gas, the introduction flow rate of water into the azeotropic equipment, downstream position of the boiling area of the co-mixture of water and formic acid in the interior of the boiling equipment, substantially formate and setting as contaminating water single no boiling region occurs.
According to the present invention, the carbon monoxide gas produced by the dehydration reaction of formic acid introduced into the aqueous sulfuric acid solution contains water produced by the dehydration reaction in the reactor and residual formic acid that has not been subjected to the dehydration reaction. Together with water vapor and formic acid vapor generated by heating the liquid, it is introduced into the azeotropic apparatus.
The inside of the azeotropic apparatus can maintain the boiling region of the azeotropic mixture of water and formic acid by heating with the heating device, and is downstream in the flow of the carbon monoxide gas from the boiling region of the azeotropic mixture having the maximum azeotropic point. A substantially single water boiling region can be maintained in position. Further, the internal temperature of the azeotropic apparatus naturally decreases as the carbon monoxide gas flows from upstream to downstream. Therefore, the water vapor and formic acid vapor introduced to the azeotropic apparatus at a temperature exceeding the azeotropic point of the azeotropic mixture of water and formic acid creates a boiling region of the mixture of water and formic acid due to a temperature drop in the azeotropic apparatus.
Furthermore, water vapor is generated by boiling water introduced into the azeotropic apparatus. It is preferable to introduce water into the azeotropic apparatus continuously or intermittently. By appropriately setting the flow rate of water introduced into the azeotropic apparatus, the ratio of formic acid vapor to water vapor introduced into the azeotropic apparatus is larger than the ratio of formic acid to water in the azeotropic mixture. Creating a boiling region of the mixture of formic acid and water from all the formic acid vapor and water vapor introduced into the azeotropic apparatus and producing a substantially single boiling region of water downstream of the boiling region of the mixture. Can do.
Thus, the formic acid vapor is prevented from flowing downstream by the azeotropic apparatus. Carbon monoxide gas flows out of the azeotrope with water vapor and is then isolated. Note that formic acid may be slightly mixed in a single boiling region of water due to reasons such as it is actually difficult to complete gas-liquid contact in an azeotropic apparatus. In order to prevent the water from flowing out of the reaction system, it is only necessary that the boiling area of the single water is maintained downstream from the boiling area of the azeotrope.
In addition, when the azeotropic apparatus is disposed above the reactor, a part of the mixture of formic acid and water in the azeotropic apparatus is formic acid water close to the composition of the azeotropic mixture, and the inner surface of the azeotropic apparatus by gravity. Flows downward along the path and flows out of the azeotropic apparatus. A part of the formic acid water flowing out from the azeotropic apparatus is converted into water vapor and formic acid vapor to be introduced again into the azeotropic apparatus, while the remainder flows toward the reactor. That is, residual formic acid can be recovered and returned to the reaction system.

The apparatus of the present invention is produced by a reactor for storing a heated reaction solution containing at least a sulfuric acid aqueous solution, a formic acid introduction path capable of continuously introducing formic acid into the reaction solution in the reactor, and a dehydration reaction of formic acid. A carbon monoxide gas manufacturing apparatus comprising an outflow passage for causing the carbon monoxide gas to flow out of the reactor, and water vapor and residual gas that are disposed in the outflow passage and are generated by heating the reaction liquid in the reactor The azeotropic apparatus in which the formic acid vapor is introduced together with the carbon monoxide gas, the water vapor and the residual formic acid vapor introduced into the azeotropic apparatus, and the azeotropic point of the azeotropic mixture of water and formic acid before the introduction. A heating device for heating to a temperature higher than that, and a boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic device, and at a position downstream of the boiling region of the azeotropic mixture in the flow of carbon monoxide gas. substantially formic acid is mixed So as to maintain the water single boiling region not, a heating device for heating the azeotropic equipment, and a liquid inlet for introducing water to the azeotropic equipment, from the azeotropic equipment An isolator for isolating the carbon monoxide gas flowing out together with the water vapor, and the flow rate of water introduced into the azeotropic apparatus is downstream of the boiling region of the mixture of water and formic acid inside the azeotropic apparatus. It is characterized in that a single boiling region of water substantially free of formic acid is generated at the position.
According to the apparatus of the present invention, the method of the present invention can be carried out.

  In the method of the present invention, it is preferable that condensed water of water vapor flowing out from the azeotropic apparatus is used as the water introduced into the azeotropic apparatus. In this case, the apparatus of the present invention preferably includes a condenser for water vapor flowing out from the azeotropic apparatus, and a liquid reflux path for leading condensed water from the condenser to the liquid inlet. Thereby, the water produced | generated by a dehydration reaction can be used effectively.

  In the apparatus of the present invention, the azeotropic apparatus 20 is constituted by a packed tower or a plate tower having a lower end inlet 20a and an upper end outlet 20b, and between the lower end inlet 20a and the upper end outlet 20b. The liquid inlet 20c is preferably arranged. Thereby, each boiling area | region can be produced easily.

  According to the present invention, when producing carbon monoxide gas by a continuous dehydration reaction of formic acid using an aqueous sulfuric acid solution, residual formic acid not subjected to the reaction is prevented from flowing out of the reaction system. It can contribute to the industrial production of carbon oxide gas.

Configuration explanatory diagram of a carbon monoxide gas production apparatus according to an embodiment of the present invention

  FIG. 1 shows a carbon monoxide gas production apparatus 1 according to an embodiment of the present invention. The production apparatus 1 includes a reactor 2 that stores a reaction solution containing at least a sulfuric acid aqueous solution, and a heating device 3 that heats the sulfuric acid aqueous solution in the reactor 2. The heating device 3 is constituted by, for example, a heater capable of controlling the heating temperature, and is attached to the reactor 2.

  A formic acid introduction path 4 for continuously introducing formic acid into the reaction solution in the reactor 2 is provided. One end of the formic acid introduction path 4 is connected to the formic acid supply source 5, and the other end is disposed in the reaction liquid in the reactor 2, and liquid formic acid is transferred to the reaction liquid in the reactor 2 through the formic acid introduction path 4. It is introduced at a preset flow rate via a flow rate controller (not shown) such as a flow rate control valve. Thereby, carbon monoxide gas and water are produced by a dehydration reaction of formic acid introduced into the sulfuric acid aqueous solution.

  The initial concentration of the aqueous sulfuric acid solution stored in the reactor 2 is not particularly limited. However, when the dehydration reaction is started quickly, it is preferably 70% by weight or more. The temperature of the sulfuric acid aqueous solution in the reactor 2 is preferably 140 to 220 ° C. At 140 ° C. or lower, productivity decreases, and at 220 ° C. or higher, the amount of formic acid that evaporates before being subjected to the dehydration reaction increases. The reaction liquid stored in the reactor 2 is a sulfuric acid aqueous solution until formic acid is introduced from the formic acid introduction path 4, and is a mixture of residual formic acid and sulfuric acid aqueous solution that has not been subjected to a dehydration reaction after the introduction of formic acid. The concentration of formic acid is not particularly limited, but is preferably 50% by weight or more, and more preferably 70% by weight or more from an industrial standpoint. The introduction rate of formic acid into the sulfuric acid aqueous solution may be experimentally set to an appropriate value so that carbon monoxide gas can be efficiently produced according to the reaction temperature or the like.

  An outflow path 6 is provided for allowing carbon monoxide gas generated by the dehydration reaction of formic acid to flow out of the reactor 2. One end of the outflow path 6 is connected to the reactor 2, extends upward from one end, and the other end is connected to one end of the discharge pipe 7. The carbon monoxide gas generated in the reactor 2 flows upward in the outflow path 6.

  A gas-liquid contact device 10 and an azeotropic device 20 are disposed in the outflow path 6. The gas-liquid contact device 10 and the azeotropic device 20 are arranged in series, and the gas-liquid contact device 10 is located upstream of the azeotropic device 20 in the flow of carbon monoxide gas. In the present embodiment, the gas-liquid contact device 10 and the azeotropic device 20 are each constituted by a packed tower. The packing packed in each packed tower is not particularly limited, and for example, Raschig ring can be used. Each of the gas-liquid contact devices 10 and 20 is not limited to a packed tower, and may be any one that can contact a flowing gas and a liquid. For example, a plate tower such as a bubble bell tower or a perforated plate tower. You may comprise by.

  A circulation device 11 that circulates the reaction solution between the gas-liquid contact device 10 and the reactor 2 and a heating device 12 that heats the reaction solution in the gas-liquid contact device 10 are provided. The circulation device 11 has a pipe 11 a that connects the inside of the reactor 2 and the upper region of the gas-liquid contact device 10 in the outflow path 6, and a pump 11 b that can control the discharge flow rate arranged in the middle of the pipe 11 a. The reaction liquid in the reactor 2 sent to the upper side of the gas-liquid contact device 10 via the pipe 11a by the pump 11b is dropped by gravity and introduced into the gas-liquid contact device 10 from the upper end outlet 10b. Reflux to reactor 2. Thereby, the reaction liquid circulates between the gas-liquid contact device 10 and the reactor 2. The heating device 12 is composed of, for example, a heater capable of controlling the heating temperature, and is built in a jacket that covers the outer periphery of the gas-liquid contact device 10, and heats the reaction liquid in the gas-liquid contact device 10 from the outside. It is preferable that the temperature of the reaction liquid in the gas-liquid contact apparatus 10 is set to a temperature equal to or higher than the temperature of the reaction liquid in the reactor 2 and equal to or lower than 220 ° C. by heating by the heating device 12. It is preferable that the height of the gas-liquid contact device 10 is set so as to exhibit a performance of 3 to 6 stages in terms of the number of theoretical stages.

  Since carbon monoxide gas is continuously generated by the dehydration reaction of formic acid in the reactor 2, a flow of carbon monoxide gas from the reactor 2 toward the outflow path 6 occurs. Thereby, the carbon monoxide gas is introduced into the gas-liquid contact device 10 from the lower end inlet 10a together with the water vapor generated by heating the reaction liquid in the reactor 2. Further, residual formic acid vapor is generated by heating the reaction liquid in the reactor 2, and the residual formic acid vapor is also introduced into the gas-liquid contact device 10 from the lower end inlet 10 a together with the carbon monoxide gas. In the gas-liquid contact device 10, water vapor generated by heating the reaction liquid in the gas-liquid contact device 10 and the residual formic acid vapor are mixed with the carbon monoxide gas introduced into the gas-liquid contact device 10. Carbon monoxide gas and the reaction solution are contacted. In the gas-liquid contact device 10, the reaction liquid flows downward and the carbon monoxide gas flows upward, so that the contact between the reaction liquid and the carbon monoxide gas is countercurrent contact. The carbon monoxide gas introduced into the gas-liquid contact device 10 flows out from the upper end outlet 10b together with the vapor of water vapor and residual formic acid.

  Thereby, even if the water vapor contained in the carbon monoxide gas is not saturated between the reactor 2 and the gas-liquid contact device 10, the water vapor contained in the carbon monoxide gas is increased in the gas-liquid contact device 10. In addition, the carbon monoxide gas can be saturated with water vapor. On the other hand, the concentration of the sulfuric acid aqueous solution is maintained at a value that balances the amount of water produced by the dehydration reaction and the amount of water flowing out with the carbon monoxide gas as water vapor. Therefore, the sulfuric acid contained in the reaction liquid in the gas-liquid contact device 10 is increased even if the amount of water vapor generated relative to the amount of carbon monoxide gas is reduced by increasing the formic acid introduction rate to improve productivity. The aqueous solution can be concentrated. That is, the concentration of the sulfuric acid aqueous solution can be suppressed without being heated at a high temperature, and the sulfuric acid aqueous solution can be continuously used without being discarded, thereby improving productivity when industrially producing carbon monoxide gas. . Further, since the concentration of the sulfuric acid aqueous solution in the gas-liquid contact device 10 is higher than that of the sulfuric acid aqueous solution in the reactor 2, the vapor of residual formic acid introduced into the gas-liquid contact device 10 comes into contact with the sulfuric acid aqueous solution. In the contact device, formic acid is decomposed at a faster rate than in the reactor 2, and the productivity of carbon monoxide gas can be improved.

  Carbon monoxide gas flowing out from the gas-liquid contact device 10 is introduced into the azeotropic apparatus 20 together with water vapor and residual formic acid vapor. That is, steam and residual formic acid vapor generated by heating of the reaction liquid in the reactor 2 and water vapor and residual formic acid vapor generated by heating of the reaction liquid in the gas-liquid contact device 10 are produced by the generated carbon monoxide gas. At the same time, it is introduced into the azeotropic apparatus 20 from the lower end inlet 20a.

  The temperature of the water vapor and the residual formic acid vapor introduced from the lower end inlet 20a into the azeotropic apparatus 20 is heated by the heating apparatuses 3 and 12 before the introduction, so that the azeotropic point of the azeotropic mixture of water and formic acid is obtained. A value exceeding At standard atmospheric pressure, the boiling point of water alone is 100 ° C., and the boiling point of formic acid alone is 100.8 ° C. On the other hand, the mixture of water and formic acid becomes an azeotrope when the composition of water is 25.5% by weight, and the azeotropic point is 107.7 ° C. at standard atmospheric pressure.

  The boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic apparatus 20, and is located at a position downstream of the boiling region of the azeotropic mixture having the maximum azeotropic point in the flow of carbon monoxide gas (this embodiment). In the upper position, a heating device 21 for heating the azeotropic device 20 is provided so that a substantially single boiling region of water can be maintained. The heating device 21 is constituted by, for example, a heater capable of controlling the heating temperature, and is built in a jacket that covers the outer periphery of the azeotropic device 20. The upper end outlet 20b of the azeotropic apparatus 20 communicates with the atmosphere, which is a non-heating region. In this embodiment, the heating temperature by the heating apparatus 21 is constant, so that the internal temperature of the azeotropic apparatus 20 is increased. Is assumed to decrease from upstream to downstream of the flow of carbon monoxide gas. When the temperature of the water vapor and formic acid vapor introduced from the lower end inlet 20a to the azeotropic apparatus 20 is sufficiently higher than the azeotropic point, the inside of the azeotropic apparatus 20 is maintained even if the heating temperature by the heating device 21 is less than the azeotropic point. The boiling point of the azeotropic mixture of water and formic acid can be maintained above the azeotropic point that can be maintained. In order to maintain a substantially single boiling region of water, the temperature at the upper end outlet 20b of the azeotropic apparatus 20 may be set to the boiling point of water. What is necessary is just to obtain | require experimentally the specific value of the heating temperature of the azeotropic apparatus 20 by the heating apparatus 21. FIG. It is preferable that the height of the azeotropic apparatus 20 is set so that the performance is 5 or more in terms of the number of theoretical plates.

  A liquid inlet 20c through which water can be continuously introduced into the azeotropic apparatus 20 is provided. The other end of the liquid introduction path 22 connected at one end to the tank 23 is connected to the liquid introduction port 20c. The liquid inlet 20c is disposed between the lower end inlet 20a and the upper end outlet 20b of the azeotropic apparatus 20. Thereby, the liquid inlet 20c is disposed at a downstream position in the flow of the carbon monoxide gas with respect to the position where the water vapor and residual formic acid vapor are introduced into the azeotropic apparatus 20. Water stored in the tank 23 is introduced into the azeotropic apparatus 20 via the liquid inlet 20c by a pump 24 that can control the discharge flow rate disposed in the middle of the liquid introduction path 22.

The introduction flow rate of water through the liquid inlet 20c to the azeotropic apparatus 20 is such that the boiling area of the single water is substantially at the downstream position of the boiling area of the mixture of water and formic acid inside the azeotropic apparatus 20. The flow rate required to occur is set.
If the ratio of formic acid vapor to the water vapor introduced from the lower end inlet 20a of the azeotropic apparatus 20 is smaller than the ratio of formic acid to water in the azeotropic mixture, a part of the water vapor and the formic acid vapor are used for azeotropy. A temperature drop in apparatus 20 creates a boiling region of the water and formic acid mixture, and the remainder of the water vapor produces a substantially single water boiling region at a location downstream of the boiling region of the water and formic acid mixture.
However, if water is not introduced from the liquid inlet 20c and the ratio of formic acid vapor to water vapor introduced from the lower end inlet 20a of the azeotropic apparatus 20 is greater than the ratio of formic acid to water in the azeotropic mixture, A part of the water vapor and formic acid vapor causes a boiling region of the mixture of water and formic acid due to a temperature drop in the azeotropic apparatus 20, and the remainder of the formic acid vapor is formed at a position downstream of the boiling region of the mixture due to a further temperature drop. A single boiling region is produced.
On the other hand, when the ratio of formic acid vapor to the water vapor introduced from the lower end introduction port 20a of the azeotropic apparatus 20 is larger than the ratio of formic acid to water in the azeotropic mixture, water is introduced from the liquid introduction port 20c. Thus, since the introduced water becomes water vapor in the azeotropic apparatus 20, a boiling region of a mixture of formic acid and water is generated from all the formic acid vapor and water vapor introduced into the azeotropic apparatus 20, A substantially single water boiling region can be created downstream of the boiling region of the mixture. In this case, the flow rate of water introduced from the liquid inlet 20c is higher than the value necessary for all the formic acid vapor introduced from the lower end inlet 20a to form an azeotrope from the water vapor in the azeotropic apparatus 20. A large value is set, and the specific set value may be obtained experimentally. As a result, the rate of introduction of formic acid into the sulfuric acid aqueous solution for the production of industrial carbon monoxide gas is large, and the ratio of formic acid vapor to water vapor introduced from the lower end inlet 20a of the azeotropic apparatus 20 is azeotropic. When it is larger than the ratio of formic acid to water in the mixture, formic acid vapor can be prevented from flowing downstream from the azeotropic apparatus 20. Note that the composition of the mixture of water and formic acid that constitutes the boiling region in the azeotropic apparatus 20 varies depending on, for example, fluctuations in the amount of residual formic acid vapor and water vapor, but the composition of the azeotrope or azeotrope A composition close to the composition is maintained. This prevents formic acid from flowing out of the reaction system.
Further, the gas-liquid contact device 10 is disposed above the reactor 2, and the azeotropic device 20 is disposed above the gas-liquid contact device 10, so that one of the mixture of formic acid and water in the azeotropic device 20 is obtained. The portion flows downward as a formic acid solution having a composition close to that of the azeotropic mixture, along the inner surface of the azeotropic apparatus 20 due to gravity, and flows out from the lower end inlet 20a of the azeotropic apparatus 20. A part of the formic acid water flowing out from the azeotropic apparatus 20 is converted into water vapor and formic acid vapor and introduced into the azeotropic apparatus 20 again, but the remainder flows toward the reactor 2. Formic acid constituting the formic acid water flowing toward the reactor 2 is decomposed by contacting with the sulfuric acid aqueous solution in the gas-liquid contact device 10, thereby generating carbon monoxide gas. Furthermore, a part of the formic acid water passes through the gas-liquid contact device 10 and is recovered in the reactor 2. That is, residual formic acid can be recovered and returned to the reaction system.
The introduction of water into the azeotropic apparatus 20 is not limited to the liquid inlet 20c, but instead of the liquid inlet 20c, or together with the liquid inlet 20c, from the lower end inlet 20a and / or the upper end outlet 20b. It may be introduced.

  The carbon monoxide gas that has flowed out of the gas-liquid contact device 10 together with water vapor and residual formic acid vapor flows out of the azeotropic device 20 together with water vapor, and is then isolated by the isolation device 30. The isolation device 30 of the present embodiment includes a condenser 30a connected to the outflow passage 6, and a gas-liquid separator 30b connected to the condenser 30a. The water vapor flowing out together with the carbon monoxide gas is condensed in the condenser 30a, and the carbon monoxide gas is separated from the condensed water in the gas-liquid separator 30b. The isolated carbon monoxide gas is recovered at atmospheric pressure. Thereby, the pressure in the reactor 2, the gas-liquid contact apparatus 10, and the azeotropic apparatus 20 is also made atmospheric pressure.

  A gas reflux path 31 is provided in the reactor 2 for refluxing part of the isolated carbon monoxide gas so as to contact the reaction solution. A part of the isolated carbon monoxide gas is refluxed so as to come into contact with the reaction liquid in the gas-liquid contact device 10 instead of the reactor 2, so that the gas reflux path 31 'is shown as indicated by a broken line in the figure. May be provided. Further, both reflux paths 31, 31 'may be provided.

  The water separated from the carbon monoxide gas in the gas-liquid separator 30b is introduced into the tank 23. Thereby, the liquid introduction path 22 also serves as a liquid reflux path that guides the water condensed by the condenser 30a to the liquid introduction port 20c. In addition, you may introduce | transduce water into the apparatus 20 for azeotropy via the liquid inlet 20c instead of the condensed water by the condenser 30a from a separate independent water source. Further, by providing a water intake 20d with an open / close cock leading to the boiling region of water in the vicinity of the upper end outlet 20b of the azeotropic apparatus 20, not only water is taken out from the upper end outlet 20b in a vapor state, but also a liquid You may make it take out also in this state. The water taken out from the water intake 20d may be refluxed from the liquid inlet 20c to the azeotropic apparatus 20.

The following experiment was conducted using the manufacturing apparatus 1 of the above embodiment.
The volume of the reactor 2 was 2000 ml, and 1000 g of sulfuric acid aqueous solution having a concentration of 96% by weight was stored as an initial reaction solution and heated to 180 ° C.
To the heated reaction liquid in the reactor 2, formic acid having a purity of 100% was continuously introduced at a flow rate of 100 g / min. As a result, carbon monoxide gas and water are generated by dehydration reaction of formic acid, and water vapor and residual formic acid vapor generated by heating the reaction liquid in the reactor 2 are supplied to the gas-liquid contact device 10 together with the carbon monoxide gas. It introduced from the lower end inlet 10a. The formic acid introduction rate is increased so that the ratio of formic acid vapor to the water vapor introduced from the lower end inlet 20a of the azeotropic apparatus 20 is larger than the ratio of formic acid to water in the azeotropic mixture.
The gas-liquid contact device 10 was constituted by a glass column having an inner diameter of 10 cm and a length of 20 cm, and was filled with a magnetic Raschig ring having a diameter of 6 mm, a length of 6 mm, and a thickness of 0.4 mm.
The reaction solution was circulated between the reactor 2 and the gas-liquid contact device 10 at a flow rate of 60 ml / min by the circulation device 11.
The reaction liquid in the gas-liquid contact device 10 was heated at 200 ° C. by the heating device 12 so as to be equal to or higher than the temperature of the reaction liquid in the reactor 2.
The carbon monoxide gas and the reaction liquid are brought into contact with each other in the gas-liquid contact apparatus 10, the water vapor generated by heating the reaction liquid in the gas-liquid contact apparatus 10 and the residual formic acid vapor are mixed with the carbon monoxide gas, and an azeotropic apparatus. 20 and steam of residual formic acid were introduced from the lower end inlet 20a together with carbon monoxide gas.
The azeotropic apparatus 20 was constituted by a glass column having an inner diameter of 10 cm and a length of 100 cm, and the same magnetic Raschig ring as that charged in the gas-liquid contact apparatus 10 was filled therein.
The azeotropic apparatus 20 is heated from the outside at about 110 ° C. by the heating apparatus 12, and the boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic apparatus 20, more than the boiling region of the azeotropic mixture. A substantially single boiling region of water can be maintained at a downstream position in the carbon monoxide gas flow, and the internal temperature of the gas-liquid contact device 10 decreases as it goes from upstream to downstream of the carbon monoxide gas flow. .
The liquid inlet 20c of the azeotropic apparatus 20 was provided at a position 20 cm above the lower end inlet 20a. Water in the tank 23 was continuously introduced into the azeotropic apparatus 20 from the liquid inlet 20c. The flow rate of water introduced from the liquid inlet 20c is 200 ml / min so that a boiling region of water is substantially formed at a position downstream of the boiling region of the mixture of water and formic acid inside the azeotropic apparatus 20. Set to.
Vapor flowing out together with carbon monoxide gas from the upper end outlet 20b of the azeotropic apparatus 20 was condensed by circulating cold water at about 5 ° C. in a Liebig condenser used as the condenser 30a. The carbon monoxide gas was isolated by separating the condensed liquid and carbon monoxide gas in the gas-liquid separator 30b. The condensed liquid was introduced into the tank 23.
As a result of continuous operation of the production apparatus 1 for about 5 hours, the average increase rate of the condensed liquid is 38.4 g / min, and the average increase rate of the carbon monoxide gas is 47.1 liters / min in the standard dry volume. The carbon monoxide gas yield was 96.7%. The condensed liquid was 0.16% by weight of formic acid and the rest was water.

The same experiment as in Example 1 was performed except for the following conditions.
Heating temperature of reaction solution in reactor 2: 200 ° C
Flow rate of formic acid introduced into the reaction liquid in the reactor 2: 50 g / min Heating temperature of the reaction liquid in the gas-liquid contact device 10: 210 ° C
Circulation flow rate of reaction solution: 50 ml / min,
Flow rate of water introduction from the liquid introduction port 20c: 30 ml / min The others were the same as in Example 1.
As a result of continuous operation of the production apparatus 1 for about 5 hours, the average increase rate of the condensed liquid is 19.4 g / min, and the average increase rate of the carbon monoxide gas is 23.3 liters / min in the standard dry volume. The yield of carbon monoxide gas was 95.7%. The condensed liquid was 0.09 wt% formic acid and the rest was water.

The same experiment as in Example 1 was performed except for the following conditions.
The external heating temperature of the azeotropic apparatus 20 was set to about 80 ° C., and a part of the water taken out intermittently from the intake port 20d through the open / close cock was introduced into the azeotropic apparatus 20 from the liquid inlet 20c.
Others were the same as in Example 1.
As a result of continuous operation of the production apparatus 1 for about 5 hours, the average increase rate of the condensed liquid is 38.1 g / min, and the average increase rate of the carbon monoxide gas is 46.8 liters / minute in the dry volume in the standard state. The yield of carbon monoxide gas was 96.1%. The condensed liquid was 0.05% by weight of formic acid and the rest was water.

  From the above examples, carbon monoxide gas can be produced in high yield under conditions suitable for industrial production without discarding the sulfuric acid aqueous solution, and formic acid is substantially prevented from flowing out of the reaction system. You can confirm that you can. In the above examples, formic acid slightly flows out of the reaction system, but this is based on the fact that it is practically difficult to complete gas-liquid contact in the azeotropic apparatus. Yes, if the azeotropic apparatus is lengthened, the outflow amount to the outside of the reaction system can be made almost zero.

  The present invention is not limited to the above embodiments and examples. For example, the gas-liquid contact device 10 is not an essential component of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus of carbon monoxide gas, 2 ... Reactor, 3 ... Heating apparatus, 4 ... Formic acid introduction path, 6 ... Outflow path, 10 ... 1st gas-liquid contact apparatus, 11 ... Circulation apparatus, 12 ... Heating apparatus, DESCRIPTION OF SYMBOLS 20 ... Apparatus for azeotropy, 20c ... Liquid inlet, 21 ... Heating device, 22 ... Liquid introduction path ( liquid reflux path ) , 30 ... Isolation apparatus, 30a ... Condenser, 31 ... Gas reflux path

Claims (5)

In a method for producing carbon monoxide gas comprising a step of generating carbon monoxide gas and water by a dehydration reaction of formic acid continuously introduced into a heated reaction solution containing at least a sulfuric acid aqueous solution in a reactor,
Steam generated by heating of the reaction liquid in the reactor and residual formic acid vapor are generated together with the generated carbon monoxide gas to the azeotropic apparatus disposed in the outflow path of the carbon monoxide gas from the reactor. Introducing the process;
The boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic apparatus, and the formic acid is not substantially mixed in the downstream position in the flow of carbon monoxide gas from the boiling region of the azeotropic mixture. Heating the azeotropic apparatus so that a single boiling region of water can be maintained;
Introducing water into the azeotropic apparatus;
Isolating carbon monoxide gas flowing out from the azeotropic apparatus together with water vapor,
The flow rate of water introduced into the azeotropic apparatus is a single boiling area of water substantially free of formic acid at the downstream position of the boiling area of the mixture of water and formic acid inside the azeotropic apparatus. It sets so that it may arise, The manufacturing method of carbon monoxide gas characterized by the above-mentioned.   The method for producing carbon monoxide gas according to claim 1, wherein condensed water of water vapor flowing out from the azeotropic apparatus is used as water introduced into the azeotropic apparatus. A reactor for storing a heated reaction solution containing at least an aqueous sulfuric acid solution, a formic acid introduction path capable of continuously introducing formic acid into the reaction solution in the reactor, and carbon monoxide gas produced by a dehydration reaction of formic acid An apparatus for producing carbon monoxide gas comprising an outflow passage for causing the reactor to flow out of the reactor,
An azeotropic apparatus that is disposed in the outflow passage and into which water vapor generated by heating the reaction liquid in the reactor and vapor of residual formic acid are introduced together with carbon monoxide gas;
A heating device for heating the steam of steam and residual formic acid introduced into the azeotropic apparatus to a temperature exceeding the azeotropic point of the azeotropic mixture of water and formic acid before the introduction;
The boiling region of the azeotropic mixture of water and formic acid can be maintained inside the azeotropic apparatus, and the formic acid is not substantially mixed in the downstream position in the flow of carbon monoxide gas from the boiling region of the azeotropic mixture. A heating device for heating the azeotropic apparatus so as to maintain a single boiling region of water;
A liquid inlet for introducing water into the azeotropic apparatus;
An isolation device for isolating carbon monoxide gas flowing out together with water vapor from the azeotropic device,
The flow rate of water introduced into the azeotropic apparatus is such that a single boiling region of water substantially free of formic acid is mixed at a position downstream of the boiling region of the mixture of water and formic acid inside the azeotropic device. An apparatus for producing carbon monoxide gas, which is set so as to occur.
  The azeotropic apparatus is constituted by a packed tower or a plate tower having a lower end inlet and an upper end outlet, and the liquid inlet is disposed between the lower end inlet and the upper end outlet. Item 4. A carbon monoxide gas production apparatus according to Item 3. A condenser of water vapor flowing out of the azeotropic apparatus;
The apparatus for producing carbon monoxide gas according to claim 3, further comprising a liquid reflux path that guides the condensed water from the condenser to the liquid inlet.

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