KR20120129246A - Integral vertical silicon carbide reactor for decomposing sulfuric acid and Pressurized decomposition method of sulfuric acid using the same - Google Patents

Abstract

PURPOSE: A vertically integrated silicon carbide reactor for decomposing sulfuric acid, an apparatus for decomposing sulfuric acid using the same, and a method for decomposing sulfuric acid using the same are provided to bear high temperatures and pressures and to improve corrosion resistance to acid. CONSTITUTION: A vertically integrated silicon carbide reactor includes a silicon carbide-based bell-shaped upper tube, a silicon carbide-based bell-shaped lower tube, a silicon carbide-based center connecting part(24), and a stainless steel-based fastening part(25). The center connecting part connects the upper tube and the lower tube. The fastening part includes an aluminum liner. The center connecting part includes a sulfuric acid inlet, a sulfuric acid decomposed gas outlet, a supplying path, a discharging path, and one or more gas ascending flow path. The sulfuric acid inlet is connected to the supplying path. The sulfuric acid decomposed gas outlet is connected to the discharging path.

Description

Integral vertical silicon carbide reactor for decomposing sulfuric acid and Pressurized decomposition method of sulfuric acid using the same}

The present invention relates to a vertically integrated silicon carbide sulfate decomposition reactor, and more particularly, to withstand the corrosiveness of strongly acidic sulfuric acid and decomposition products (SO ₃ , SO ₂ , O ₂ , H ₂ O) and can be applied to high temperature, high pressure conditions The present invention relates to a vertically integrated silicon carbide sulfate reaction reactor made of a silicon carbide tube, a sulfate decomposition device including the same, and a sulfuric acid decomposition method.

Hydrogen is attracting attention as a future energy medium to replace fossil fuel, which is the main energy source of modern society, as a raw material of fuel cell or hydrogen engine. Hydrogen can be obtained by electrolysis of water, but the energy efficiency of hydrogen production is low. A more energy efficient method is thermochemical water splitting, which combines several chemical reactions to stage the decomposition of water into hydrogen and oxygen.

Sulfuric acid decomposition is the most energy-efficient method of thermochemical hydrolysis hydrogen production. Hydrogen hydrolysis is carried out by the SI thermochemical water splitting cycle or thermochemical-electrochemical cycle. One of the key reactions of the thermochemical-electrochemical hybrid water splitting cycle is the decomposition of sulfuric acid into sulfur trioxide (SO ₃ ), sulfur dioxide (SO ₂ ), oxygen (O ₂ ) and water (H ₂ O) at high temperatures. For example, the sulfur-iodine thermochemical cycle is composed of sulfuric acid decomposition, Bunsen reaction, HI decomposition reaction and the like as shown below.

H₂SO₄ → H₂O + SO₃ (One)

H₂O + SO₃ → H₂O + SO₂ + 1/2 O₂ (2)

2 H₂O + SO₂ + x I₂ → H₂SO₄ + 2 HI_x (3)

2 HI_x → xI₂ + H₂ (4)

Equations (1) and (2) are sulfuric acid decomposition reactions, and Equation (1) is an endothermic reaction with pyrolysis that proceeds as sulfuric acid evaporates and proceeds as the temperature increases. The reaction is an endothermic reaction in which SO ₃ produced in Equation (1) is decomposed into SO ₂ on a catalyst at a high temperature of 800 to 950 ° C., and the Bunsen reaction of Equation (3) is exothermic, resulting in 80-120 reaction without a catalyst. It proceeds at ℃, the HI decomposition reaction of the formula (4) is an endothermic reaction proceeds by the catalytic reaction at 400-450 ℃.

As such, the sulfuric acid decomposition reaction uses the heat of the highest temperature in the sulfur-iodine thermochemical cycle, and it is necessary to develop a reactor that can be used under high temperature and high pressure conditions and has high corrosion resistance under strong acid conditions.

Quartz (quartz) material can be used for high-temperature sulfuric acid decomposition, but when the pressure is applied at a high temperature, such as general glass, that is, it is difficult to apply to pressurized conditions because it is easily broken under high temperature, high pressure conditions.

Silicon carbide (SiC) is a compound made of silicon (Si) and carbon (C). It has a high compressive strength, little deformation even at high temperatures, and has a mixture of ceramic and metal properties with good thermal conductivity. It is a material with excellent corrosion resistance. Silicon carbide can be manufactured in various forms, but once fired, it is not easy to rebond and process. However, it resists not only organic compounds but also highly corrosive acids or alkali compounds, does not corrode at high temperatures, and has excellent mechanical strength and abrasion resistance. Therefore, heat exchange of high temperature acid exhaust gases emitted from wafer holders, acid-resistant pump bearing materials, and chemical plants in semiconductor processes It is used as a base material.

As such, the silicon carbide material can be applied to an acidic atmosphere of high temperature and has a certain mechanical strength, so that it can be applied to high pressure conditions. Therefore, it can be used as a reactor material of sulfuric acid decomposition reaction that proceeds on a catalyst of 750 ℃ or higher.

Accordingly, the first problem to be solved by the present invention is to provide a vertically integrated sulfuric acid decomposition reactor of a silicon carbide material capable of stable sulfate decomposition even under conditions of strong acidity, high temperature, and high pressure.

The second problem to be solved by the present invention is to provide a sulfuric acid decomposition device including the vertical integrated sulfuric acid decomposition reactor.

The third problem to be solved by the present invention is to use a vertically integrated silicon carbide sulfate reactor to allow a series of sulfuric acid decomposition processes such as sulfuric acid evaporation, preheating, pyrolysis, catalytic decomposition at a high temperature, pressure to occur in a single device It is to provide a sulfuric acid decomposition method for producing sulfur trioxide (SO ₃ ), water (H ₂ O), and further sulfur dioxide (SO ₂ ) and oxygen (O ₂ ) by decomposing sulfuric acid stably.

The present invention to achieve the first object,

Silicon carbide bell-shaped upper tube, silicon carbide bell-shaped lower tube, silicon carbide center connecting portion connecting the upper tube and the lower tube and aluminum liner for fastening the upper tube and the lower tube and the central connection portion A vertically integrated silicon carbide sulfate reactor comprising a fastening part of stainless steel equipped with

The central connection portion includes a sulfuric acid inlet, a sulfuric acid cracking outlet, a supply passage, an outlet passage, and one or more gas ascending passages, wherein the sulfuric acid inlet is connected to the supply passage, and the sulfated gas outlet is connected to the outlet passage. It provides a vertically integrated silicon carbide sulfuric acid decomposition reactor, characterized in that connected.

According to one embodiment of the present invention, the sulfate decomposition reactor comprises an upper inner tube and a lower inner tube, both ends of which are drilled in the respective tubes of the upper tube and the lower tube, respectively. It further includes, one end of the upper inner tube is connected to the discharge passage, one end of the lower inner tube may be connected to the supply passage.

According to an embodiment of the present invention, the sulfuric acid decomposition gas outlet is located on the upper side of the central connecting portion, the sulfuric acid inlet is located on the lower side of the central connecting portion, the discharge passage is composed of a vertical discharge passage and a horizontal discharge passage The vertical discharge passage is connected to the horizontal discharge passage downwardly from the center of the upper surface of the central connection portion along the central axis of the central connection portion, and the horizontal discharge passage is horizontally directed toward the central axis direction from the sulfuric acid decomposition gas outlet. The supply passage is connected to the vertical discharge passage, the supply passage consists of a vertical supply passage and a horizontal supply passage, the vertical supply passage and the horizontal supply passage toward the top along the central axis of the central connecting portion from the center of the lower surface of the central connecting portion; The horizontal feed passage is connected to the sulfuric acid inlet And the horizontal supply passage is connected horizontally in the direction of the central axis to the vertical supply passage, wherein the one or more gas rise passages are located at a position farther from the central axis than the vertical supply passage and the vertical discharge passage. The central connection part may be vertically penetrated so as not to meet the flow path.

According to an embodiment of the present invention, the upper tube further includes a granular sulfate decomposition catalyst layer, wherein the granular sulfate decomposition catalyst layer is installed inside the upper end of the upper inner tube, or the upper inner tube and the upper tube Can be installed in between.

According to an embodiment of the present invention, the sulfuric acid inlet and the sulfuric acid cracking gas outlet are metal tubes lined with precious metals such as platinum (Pt) and gold (Au) so as to be connected to the sulfuric acid inlet pipe and the decomposition gas discharge pipe, respectively. Can be tightened.

According to an embodiment of the present invention, since the upper inner tube and the lower inner tube are not affected by pressure, the material may be quartz or silicon carbide.

According to an embodiment of the present invention, between the upper tube and the upper inner tube, a piece of quartz tube or ceramic tube in the form of a Raschig ring may be filled.

The present invention to achieve the second technical problem,

It is to provide a sulfuric acid decomposition device for producing sulfur dioxide and oxygen by decomposing sulfuric acid, including the vertically integrated sulfuric acid decomposition reactor.

According to one embodiment of the invention, the sulfuric acid decomposition device may be connected to the vertical integrated sulfuric acid decomposition reactor in a plurality of bundles.

According to one embodiment of the present invention, the upper tube and the lower tube of the sulfuric acid decomposition reactor may further include a heating furnace capable of heating to a different temperature, respectively.

According to an embodiment of the present invention, the pressure in the sulfuric acid decomposition reactor by adjusting the sulfuric acid supply pump and the rate of sulfuric acid decomposition gas discharged from the sulfuric acid decomposition reactor to control the sulfuric acid supply rate supplied to the sulfuric acid decomposition reactor It may further include a pressure control valve.

According to an embodiment of the present invention, the sulfuric acid solution trap for capturing SO ₃ and H ₂ O discharged from the sulfuric acid decomposition reactor to separate gases SO ₂ and O ₂ , and the amount of SO ₂ generated in the sulfuric acid decomposition reactor is measured. SO _{2 to} A KI / I ₂ aqueous solution trap for collecting may be further included.

The present invention to achieve the third technical problem,

In the sulfuric acid decomposition method for producing sulfur dioxide and oxygen using the sulfuric acid decomposition device, (a) sulfuric acid solution is supplied to the lower tube through the lower inner tube, and the sulfuric acid is heated by heating the temperature of the lower tube to 350-700 ℃ Pyrolysing with SO ₃ and H ₂ O while evaporating; (b) heating the temperature of the upper tube to 700-1000 ℃ pyrolysis and the undissolved sulfate in the step (a) with additional SO ₃ and H ₂ O, the SO ₃ and H ₂ O in the catalyst layer provided on the upper tube Decomposing into SO ₂ and O ₂ ; And (c) discharging the decomposed SO ₂ and O ₂ through an upper inner tube.

According to an embodiment of the present invention, the step (a) may further comprise the step of adjusting the rate of supply of sulfuric acid solution, the sulfuric acid solution may be supplied at 5.0-15.0 g / min.

According to an embodiment of the present invention, the step (c) may further include adjusting the pressure of the sulfate decomposition reactor by adjusting the discharge rate of the decomposed SO ₂ and O ₂ , the pressure of the sulfate decomposition reactor May be 0.2-5.0 atmospheres.

The vertically integrated silicon carbide sulfate decomposition reactor according to the present invention can withstand high temperature and high pressure and has excellent corrosion resistance against acid to perform pressurized sulfate decomposition reaction which is difficult to realize with conventional glass (pyrex) or quartz, and bell type silicon carbide. It is an integrated reactor in which two tubes are connected vertically to separate sulfuric acid evaporation, preheating, pyrolysis and catalytic decomposition to secure a large heat transfer area and efficiently supply heat for sulfuric acid evaporation, preheating, pyrolysis and catalytic decomposition. Sulfuric acid decomposition conversion rate can be maintained. In addition, a plurality of vertically integrated sulfuric acid decomposition reactors may be arranged in a row, or such a serial arrangement may be arranged in a row to constitute a mass production process of SO ₂ and O ₂ .

1 is a schematic view showing a pressurized sulfuric acid decomposition device and a sulfuric acid decomposition method including a vertically integrated silicon carbide reactor according to an embodiment of the present invention.
2 is an assembly view of a vertically integrated silicon carbide reactor for pressurized sulfuric acid decomposition.
Figure 3 is a detailed view of the silicon carbide tube used in the vertically integrated silicon carbide reactor for pressure sulfate decomposition.
Figure 4 is a detailed view showing the silicon carbide center connection used in the vertically integrated silicon carbide reactor for sulfuric acid decomposition and the silicon carbide or quartz inner tube connected thereto.
5 is a view showing a granular catalyst layer installation method for sulfuric acid decomposition.
6 is a conceptual diagram of a large-capacity pressurized sulfuric acid decomposition apparatus in which several integrated silicon carbide reactors are connected.

Hereinafter, the present invention will be described in more detail with reference to the reference numerals.

The present invention can be used to prepare sulfur trioxide (SO ₃ ), water (H ₂ O), further sulfur dioxide (SO ₂ ) and oxygen (O ₂ ) by evaporation, preheating, pyrolysis and catalytic cracking of sulfuric acid under high temperature and high pressure conditions. A vertically integrated sulfuric acid reactor in which one end of a closed bell tube of silicon carbide (SiC) is suitable for high temperature sulfuric acid reaction, and two bell silicon carbide tubes are placed vertically above and below the silicon carbide center connection. It is characterized in that the vertically integrated sulfuric acid decomposition reactors connected to each other and installed in the inner tube with both ends in each tube.

The vertical integrated sulfuric acid decomposition reactor according to the present invention will be described with reference to FIGS. 2, 3, 4 and 5.

As shown in FIG. 2, the vertically integrated silicon carbide reactor for sulfuric acid decomposition according to the present invention includes two bell-shaped silicon carbide tubes 21 at which one end of a silicon carbide material suitable for high temperature decomposition reaction is blocked. It is a vertically integrated sulfuric acid reactor in which a silicon carbide intermediate connector 24 is connected up and down, and inner tubes 22 of quartz or silicon carbide, both ends of which are drilled at both upper and lower silicon carbide tubes, are installed.

While heating the upper and lower silicon carbide tubes with two heating furnaces at different temperatures, the raw sulfuric acid solution is introduced into the silicon carbide center connector 24 so that sulfuric acid flows down along the lower inner tube and the lower silicon carbide tube Heated and evaporated at 21, the generated gas is preheated as it rises, and the preheated gas is heated to a high temperature in the upper silicon carbide tube as it moves up to the upper tube along the gas rise passage of the central connection 24, Pyrolysates to sulfur trioxide (SO ₃ ) and water (H ₂ O), which are heated again to a higher temperature, rising again and catalyzed by sulfur dioxide (SO ₂ ) and oxygen (O ₂ ) as they pass through the sulfuric acid decomposition catalyst layer (23). After the reaction, the mixed gas containing SO ₂ and O ₂ is lowered along the inner tube 22 in the upper silicon carbide tube and discharged to the outside along the flow path of the central connection portion 24. It is characterized by producing a SO ₂ , O ₂ from sulfuric acid through a series of processes.

As described above, the vertically integrated sulfuric acid reactor according to the present invention, in which two bell-type silicon carbide tubes are connected vertically and vertically, performs evaporation, preheating, pyrolysis, and catalytic decomposition of sulfuric acid, thereby providing a heat transfer area of one bell-type silicon carbide tube. By more than doubling, sulfur dioxide production rates can be nearly doubled in the same horizontal space.

In addition, by using a silicon carbide lower tube connected to the lower portion of the silicon carbide intermediate connection as the sulfuric acid evaporator, preheating unit and a silicon carbide upper tube connected to the upper portion as the sulfuric acid decomposition reaction unit, and maintaining the temperature of the silicon carbide upper tube and the lower tube different By dispersing the large temperature gradient that one silicon carbide tube must undergo in two, it is possible to reduce the possibility of thermal shock damage of the silicon carbide tube.

Vertically integrated sulfuric acid decomposition reactor combining two bell-shaped silicon carbide tube according to the present invention uses a bell-shaped silicon carbide tube as an outer tube, and the inner tube 22 having both ends of quartz or silicon carbide material is installed therein. By doubling the flow length of the fluid to increase the heat transfer area is characterized in that the heat transfer time is increased.

In addition, the high temperature heat required for evaporation of sulfuric acid and the preheat decomposition reaction is transferred from the outside to the inside through the silicon carbide tube wall, a piece of quartz tube in the form of a Raschig ring between the silicon carbide tube and the inner tube, or Filling a piece of ceramic tube ensures that the high temperature heat transferred inside the silicon carbide tube is well transferred to the fluid flowing between the silicon carbide tube and the inner tube.

In the vertically integrated sulfuric acid reactor according to the present invention, a catalyst is charged in the sulfate decomposition catalyst layer 23 installed at the upper end of the upper silicon carbide tube and heated to a high temperature of 800-1000 ° C. so that sulfuric acid is decomposed into SO ₂ and O ₂ . It is characterized by inducing.

At this time, the sulfuric acid decomposition catalyst layer 23 may be installed between the upper silicon carbide tube and the inner tube as shown in Figure 5 or may be installed 44 above the inner tube.

In the case of installing 45 between the upper silicon carbide tube and the inner tube, as shown in FIG. 5, a ring-shaped catalyst layer support 46 is inserted into the outer wall of the inner tube, and the catalyst is filled therein. In order to prevent the catalyst from flowing inside, paste the paper on the upper part of the inner tube to close the hole and fill the granular catalyst. When the integrated reactor with the catalyst filling is installed vertically and heated to a high temperature, the paper blocking the upper hole of the inner tube is burned out to secure a flow path through which gas can flow.

In the case of installing the catalyst 44 on the upper part of the inner tube, a quartz plate or quartz wool having a wide opening and a plurality of narrow holes in the narrowest part can be expanded to fill the upper part of the inner tube as shown in FIG. 5. To support the catalyst particles.

3 shows a silicon carbide tube used in a vertically integrated silicon carbide reactor for pressurized sulfuric acid decomposition according to the present invention, wherein the jaw sloped at 45 ° at the end of the upper silicon carbide tube and the lower silicon carbide tube is skirted (34). The graphite gasket is put on the surface in contact with the silicon carbide center connection, and the chin inclined in the skirt shape is fastened with the stainless steel metal holder (25) shown in FIG. . The silicon carbide skirt and the metal holder 25 and the metal bolts fixing them have different coefficients of thermal expansion, and as the temperature increases, the thermal expansion of the metal increases, and the force to tighten the upper and lower silicon carbide tubes to the silicon carbide center connection becomes loose. The airtightness is inferior. In order to prevent this, a thin ring-shaped aluminum liner 30 is inserted between the silicon carbide inclined surface and the metal holder. The inclined ring-shaped aluminum liner expands more than the metal holder at higher temperatures, while tightening the upper and lower silicon carbide tube skirts to maintain airtightness.

The silicon carbide center connecting portion 24, in which two silicon carbide tubes are connected up and down and at the same time, an inner tube installed in the silicon carbide tube, is assembled, is provided with sulfuric acid supplied from the outside, as shown in FIGS. A supply flow passage is installed at the center to flow through the inner tube, and a half moon gas rise passage 38 is installed to transfer the SO ₃ and H ₂ O gas generated at the lower portion thereof, and decomposed and generated by the catalyst at the upper portion thereof. A discharge passage is installed at the center so that SO ₂ , O ₂ and unreacted gas are discharged to the outside along the upper inner tube.

After reacting with the sulfuric acid inlet 28 of the silicon carbide central connection, the sulfuric acid decomposition gas outlet 29 has a graphite gasket containing a precious metal lining tube 26 lining the inside with precious metals such as platinum (Pt) and gold (Au). Connect using to connect with sulfuric acid input pipe and gas discharge pipe.

When the sulfuric acid is decomposed using the sulfuric acid decomposition reactor according to the present invention, the evaporation and pyrolysis temperature of sulfuric acid may vary depending on the internal pressure of the sulfuric acid reactor, but sulfuric acid evaporation and preheating occur and thermal decomposition of SO ₃ and H ₂ O occurs. The starting lower silicon carbide tube maintains its internal temperature in the range 350-700 ° C, while the upper silicon carbide tube undergoes additional pyrolysis and catalytic decomposition to SO ₂ , O ₂ , maintains the internal temperature at 700-1000 ° C. .

The present invention provides a sulfuric acid decomposition device including the vertical integrated sulfuric acid decomposition reactor.

Figure 1 is a schematic diagram showing a process of a sulfuric acid decomposition process and a pressurized sulfuric acid decomposition device comprising a vertically integrated silicon carbide reactor.

The sulfuric acid solution supplied from the sulfuric acid storage tank (1) to the sulfuric acid supply pump (2) is preheated down through the inner tube at the bottom of the vertical integrated sulfuric acid decomposition reactor (3), and again ascends between the bell-shaped silicon carbide lower tube and the inner tube. More heated to evaporate and partially pyrolyze into SO ₃ and H ₂ O, further heated to pyrolyze as it rises between the bell-shaped silicon carbide top tube and the inner tube through the silicon carbide central connection, and is placed on top of the granular catalyst layer 4 Catalyzed into SO ₂ and O ₂ while passing through, and after the decomposition, the mixture containing SO ₂ and O ₂ descends through the inner tube, and then is discharged to the outside through the flow path of the silicon carbide center to decompose sulfuric acid. ₂ and O ₂ will be prepared.

At this time, a temperature difference occurs between the fluid passing through the inner tube and the fluid passing between the inner tube and the silicon carbide tube, so that heat exchange occurs through the inner tube wall. It has a cooling effect.

In addition, in the sulfuric acid cracking apparatus according to the present invention, the sulfuric acid cracking gas gas after the reaction contains SO ₂ and O ₂ generated by decomposition in the reaction and SO ₃ and H ₂ O which are not decomposed in the reaction, but SO ₃ and H ₂ O is cooled and removed by recombination with sulfuric acid in the liquid phase, and gases SO ₂ and O ₂ are fed to the Bunsen reactor of the next stage. In the experiment of the present invention, SO ₃ and H ₂ O are passed through a sulfuric acid cracking gas through a gas-liquid separator (6) and a pressure regulating valve (7), through a dilute sulfuric acid trap (8) containing a dilute sulfuric acid solution having a weight ratio of 30-40%. Recombination with sulfuric acid to capture and remove, and through the three-way valve (9) through an alkali aqueous solution trap (12) containing an aqueous alkali solution such as KOH or NaOH to remove SO ₂ and to discharge only O ₂ harmless to the environment By measuring the flow rate, the rate of decomposition of sulfuric acid into SO ₂ , O ₂ is monitored.

In the sulfuric acid cracking device according to the present invention, in order to precisely investigate the decomposition rate of sulfuric acid into SO ₂ , O ₂ , the flow path is intermittently changed using a three-way valve 9 to pass through the KI / I ₂ aqueous solution trap 10. SO ₂ is collected and only O ₂ is passed through the dry gas meter (11) and discharged to the atmosphere.

At this time, KI / I ₂ solution of SO ₂ captured the KI / I ₂ solution of the trap 10 in the proper KI / I ₂ solution by calculating the concentration changes by KI SO ₂ generated by estimating the quantity and simultaneously measuring the amount of O ₂ that has passed through the dry gas meter (11) To estimate the amount, the SO ₂ measured in two ways: The quantities actually represent similar values to each other.

In particular, in the sulfuric acid cracking apparatus according to the present invention, the supply rate of sulfuric acid is controlled by the sulfuric acid supply pump (2), the temperature of the upper and lower silicon carbide tube of the vertically integrated sulfuric acid decomposition reactor (3) is heated outside thereof The pressure of the sulfuric acid decomposition, that is, the pressure in the sulfuric acid decomposition reactor 3 may be adjusted to a specific pressure by controlling the discharge rate of sulfuric acid decomposition gas by the pressure regulating valve 7.

The present invention provides a sulfuric acid decomposition device in which the vertical integrated sulfuric acid decomposition reactor is connected to a plurality of bundles.

The bell-shaped silicon carbide tube requires a molding and heat treatment process, so the length that can be manufactured is limited. Thus, SO ₂ and O ₂ can be produced using one vertically integrated sulfuric acid reactor. The amount is bound to be limited. Therefore, there is a need for a method of increasing the amount of sulfuric acid decomposition by connecting several integrated sulfuric acid decomposition reactors in a bundle.

6 is a conceptual diagram of a large-capacity pressurized sulfuric acid cracking device in which several vertically integrated silicon carbide sulfate decomposition reactors are connected, and the sulfuric acid solution is dispersed and supplied to each integrated reactor 51 through one sulfuric acid solution inlet 54, The mixed gas discharged after the reaction in the individual reactors is collected in one sulfuric acid decomposition gas outlet 55 and supplied to the Bunsen reaction part of the next step.

In the vertical integrated sulfuric acid reactor 51 composed of a bundle, an upper heating block 52 for heating the upper tube and a lower heating block 53 for heating the lower tube may be installed in each individual reactor, or several may be simultaneously heated. It is also possible to use a heating block made of large blocks. In addition, when the amount of sulfuric acid decomposition increases, the reactor installation space may be minimized by installing parallel sulfuric acid reactors connected in a row in a manner as illustrated in FIG. 6.

The present invention provides a sulfuric acid decomposition method for producing sulfur dioxide and oxygen using the sulfuric acid decomposition device, the sulfuric acid decomposition method according to the present invention supplies a sulfuric acid solution to the lower tube through the lower inner tube, the temperature of the lower tube Evaporation of sulfuric acid by heating to 350-700 ° C. and pyrolysis of SO ₃ and H ₂ O, heating the temperature of the upper tube to 700-1000 ° C. to further disintegrate the undissolved sulfuric acid into SO ₃ and H ₂ O Pyrolysing, decomposing SO ₃ and H ₂ O into SO ₂ and O ₂ in a catalyst layer installed on the upper tube and discharging the decomposed SO ₂ and O ₂ through the upper inner tube. .

The catalyst layer is not limited thereto, but a catalyst for sulfuric acid decomposition may be formed of a granular catalyst supported by a noble metal or a metal oxide granular catalyst such as CuFeO _x or CuCrO _x , and preferably, alumina in which platinum is supported by 0.5-1% by weight. It is characterized by consisting of a granular catalyst (0.5-1 wt% Pt / Al ₂ O ₃ ).

In addition, a means for adjusting the rate of supplying sulfuric acid solution, characterized in that for supplying the sulfuric acid solution at 5-35 g / min, by adjusting the discharge rate of the decomposed SO ₂ and O ₂ Sulfate decomposition reactor Means for adjusting the pressure of, characterized in that for adjusting the pressure of the sulfuric acid decomposition reactor to 0.2-5 atm.

The sulfuric acid solution feed rate is controlled by feeding the metering pump in consideration of the amount of heat transferred through the silicon carbide tube and the amount of heat required for evaporation, preheating, pyrolysis, and catalytic decomposition per unit weight of sulfuric acid. Sulfuric acid solution (weight ratio 95-97% sulfuric acid) can be supplied at 2-10 g / min when using 56-inch bell-shaped silicon carbide tubes at 2-20 g / min. However, since the filling amount of the catalyst is limited in the actual size of the silicon carbide tube currently available for purchase, it is preferable to supply at a level of 40-50% of the amount.

The lower tube responsible for the evaporation of sulfuric acid solution, partial gas heating and pyrolysis is heated to 350-700 ° C., preferably 500-600 ° C., and the upper tube responsible for pyrolysis and catalytic decomposition of sulfuric acid vapor is 700-1000. Preference is given to heating to a temperature of preferably 850-900 ° C.

Hereinafter, a sulfuric acid decomposition method using a sulfuric acid decomposition apparatus including a vertically integrated sulfuric acid decomposition reactor according to the present invention will be described in more detail. It will be apparent, however, to those skilled in the art that these embodiments are for further explanation of the present invention and that the scope of the present invention is not limited thereby.

<Examples>

&Lt; Example 1 >

Pressurized sulfate decomposition experiments were performed using a vertically integrated silicon carbide sulfate reactor according to the present invention.

As shown in FIG. 2, the integrated sulfuric acid decomposition reactor has two bell-shaped silicon carbide tubes of 28 inches (712 mm) long, 38 mm outer diameter, and 25.5 mm inner diameter up and down at the center connection of the silicon carbide material. 4, a quartz tube (outer diameter of 9.5 mm, inner diameter of 6.4 mm) or silicon carbide tube (outer diameter of 3/8 inch, inner diameter of 1/4 inch) inside each silicon carbide tube with a screw thread 43 at the end as shown in FIG. Phosphorus upper inner tube (41) and lower inner tube (42) were inserted into the silicon carbide center connecting portion (35). The inner tube installed in the upper part of the vertical reactor is an alumina granular catalyst (1 wt% Pt / Al ₂ O ₃ granular catalyst, 1/8 in diameter, loaded with 1% platinum by weight) as a catalyst for sulfuric acid decomposition at the top of the reactor. Inch, 2-2.5 mm) was used to fill 30.6 g (˜27 cc), and the catalyst bed temperature was adjusted to 860 ° C. based on the silicon carbide tube outer wall temperature. The sulfuric acid solution as a raw material used a reagent grade having a sulfuric acid concentration of 97% by weight. The sulfuric acid solution was supplied at a rate of 8.5 g per minute, and the reaction pressure was controlled at an exhaust gas rate to maintain 2.5 atm. Gas of sulfuric acid decomposition gas discharged from a sulfuric acid decomposition reactor by passing a dilute sulfuric acid solution trap to remove unreacted sulfuric acid and water, and discharged for a period of time in a dry gas meter to remove the SO ₂ was passed through a KI / I ₂ solution traps O ₂ The volume of was measured and the value was converted into reference conditions (25 degreeC, normal pressure). The sulfuric acid decomposition rate (%) measured experimentally was calculated according to the following [Formula 1] and [Formula 2].

[Formula 1]

Volume of O ₂ produced by 100% decomposition of sulfuric acid (L / h, 25 ° C, atmospheric pressure)

= (Sulfate solution input, g / min) × 0.97 / 98 (H ₂ SO ₄ molecular weight, g / gmol) × 22.4 (L / gmol) / 2 × 60 (min / h)

[Formula 2]

Laboratory sulfuric acid decomposition rate (%)

= 100 × {Temperature calibrated volume of experimental measurement O ₂ (L / h, 25 ° C, atmospheric pressure)} / {Volume of O ₂ produced by 100% sulfuric acid decomposition (L / h, 25 ° C, atmospheric pressure)}

When the sulfuric acid solution is added at 8.5 g / min, the amount of O ₂ produced assuming 100% conversion of sulfuric acid is 56.54 L / h based on the condition of 25 ℃ and atmospheric pressure. The amount of O ₂ produced through sulfuric acid decomposition experiment (25 ° C, atmospheric pressure) was measured at 43.8 ± 1.3 L / h, and the decomposition rate of H ₂ SO ₄ to SO ₂ , O ₂ was calculated to be 77.5 ± 2.3%. Thermodynamically predicted equilibrium conversion of H ₂ SO ₄ to SO ₂ , O ₂ at 860 ° C. and 2.5 atmospheres (barometric pressure) was 77.79%, and the average value measured in the experiment approached the equilibrium conversion value. This result shows that when sulfuric acid solution is added at 8.5 g / min, the contact reaction time with the catalyst is sufficient, and the heat transfer through the silicon carbide tube wall is sufficient to provide sufficient heat for evaporation, preheating, pyrolysis and catalytic decomposition of sulfuric acid solution. It can be seen that it was supplied.

<Examples 2 to 4>

The sulfuric acid decomposition reaction was carried out at 855-860 ° C. and 2.5 atm (atmospheric pressure) in the same manner as in Example 1, except that the sulfuric acid solution feed rate was changed to 12.5-35.0 g / min. To the decomposition conversion of the production rate of O ₂ and H ₂ SO ₄ to SO _2, O ₂ for each feed rate of the sulfuric acid solution are summarized in Table 1.

As the feed rate of sulfuric acid solution increased, the rate of O ₂ formation and the rate of decomposition conversion of H ₂ SO ₄ to SO ₂ and O ₂ decreased proportionally, and when supplied at a rate of 35.0 g / min, H ₂ SO ₄ The degradation conversion was calculated to be 42.6 ± 0.6%, reaching 55% of the equilibrium conversion (77.79%). This suggests that as the sulfuric acid solution supply speed increases, the amount of heat transfer through the silicon carbide tube wall is less than the amount of heat required for evaporation, preheating, pyrolysis, and catalytic decomposition of sulfuric acid solution.

<Examples 5 to 7>

The sulfuric acid solution feed rate was fixed at 35.0 g / min, and the catalytic reaction temperature was changed to 900 ° C. at a reaction pressure of 2.5 atm (Example 5) and at 860-900 at a reaction pressure of 5 atm (atmospheric pressure). The sulfuric acid decomposition reaction was performed about the case where it changed to ° C (Examples 6 and 7). The conversion rate to decompose to SO _2, O ₂ production rate of the O ₂ and H ₂ SO ₄ for each case are summarized in Table 1.

As in Example 5, when the reaction temperature was increased to 900 ° C. at a reaction pressure of 2.5 atm (atmospheric pressure), the equilibrium conversion rate was increased to 83.23% by thermodynamic calculation, and SO ₂ of H ₂ SO ₄ due to the catalytic decomposition reaction measured in the experiment. ₂ , O ₂ also increased to 58.3 ± 0.5%.

As in Example 6, when the reaction pressure is increased to 5 atm (gauge), the thermodynamic equilibrium conversion rate is 72.64% at the reaction temperature of 860 ° C., and 78.98% at 900 ° C., and the conversion rate of 4-5% decreases with increasing pressure. . In the experimental results of Examples 6 and 7, a reduction of 5-7% conversion was also investigated. It can be seen that the increase in the reaction temperature of the catalyst layer induces an improvement in the reaction rate and greatly influences the increase in the rate of sulfuric acid conversion.

Example Catalytic reaction temperature
(℃) pressure
(atmospheric pressure) Sulfuric acid solution
Feed rate
(g / min) 100% conversion standard O ₂ generation rate
(L / h) * Laboratory
O ₂ production rate
(L / h) * H ₂ SO ₄ decomposition
Conversion rate
(%) One 860 2.5 8.5 56.54 43.8 ± 1.3 77.5 ± 2.3 2 860 2.5 12.5 83.14 58.8 ± 0.5 70.7 ± 0.6 3 857 2.5 25.0 166.29 80.4 ± 0.8 48.3 ± 0.5 4 855 2.5 35.0 232.80 99.1 ± 1.3 42.6 ± 0.6 5 903 2.5 35.0 232.80 135.8 ± 1.2 58.3 ± 0.5 6 857 5.0 35.0 232.80 86.9 ± 0.9 37.3 ± 0.4 7 903 5.0 35.0 232.80 120.6 ± 1.1 51.8 ± 0.5

* Volume correction value of exhaust gas (25 ℃, atmospheric pressure)

<Comparative Examples 1 to 8>

One bell-type silicon carbide tube of 28 inches (712 mm), 38 mm in diameter, and 25.5 mm in inner diameter used in Example 1 was connected to the upper portion of the silicon carbide material, and screwed on the inside thereof. A quartz tube (outer diameter of 9.5 mm, inner diameter of 6.4 mm) or silicon carbide tube (outer diameter of 3/8 inch, inner diameter of 1/4 inch) is inserted into the top of the silicon carbide center connection, and the top end thereof is sulfuric acid as in Example 1 30.6 g (˜27 cc) of 1 wt% Pt / Al ₂ O ₃ granular catalyst (diameter 1/8 inch, 2-2.5 mm in length), which is a decomposition catalyst, was charged. In the lower part of the silicon carbide center connection, instead of the bell-shaped silicon carbide tube, the plate-shaped silicon carbide lid 2 mm lower than the rim fastening part is fastened to prevent the sulfuric acid solution from being injected into the plate and the upper silicon carbide along the flow path of the silicon carbide center connection. After the liquid rises toward the tube and the sulfuric acid solution is heated in the upper tube and evaporated, preheated, pyrolyzed and catalyzed, the mixed gas descends through the inner tube after the reaction and is discharged in the same path as in Example 1 along the central connection outlet. It was made. Only the upper silicon carbide tube was heated to 850-880 ℃ based on the outer wall temperature, sulfuric acid solution was supplied at a rate of 7.7-35.0 g per minute, and the reaction pressure was controlled to the exhaust gas rate to maintain 0-3 atm. . After passing the gas discharged from the sulfuric acid decomposition reactor through the dilute sulfuric acid solution trap and the KI / I ₂ aqueous solution trap in the same manner as in Example 1, the volume of the gas O ₂ discharged for a predetermined time using a dry gas meter was measured and the reference conditions ( The sulfuric acid decomposition rate (%) was calculated by the volume of 25 degreeC, normal pressure). The conversion rate to decompose to SO _2, O ₂ in the production rate of the O ₂ measured in each of the reaction conditions and the H ₂ SO ₄ are shown in Table 2.

Comparative example Catalysis
Temperature
(℃) pressure
(atmospheric pressure) Sulfuric acid solution
Feed rate
(g / min) 100% conversion criteria O ₂ Generation speed
(L / h) * Laboratory
O ₂ Generation speed
(L / h) * H ₂ SO ₄ decomposition
Conversion rate
(%) One 847 0.2 7.7 51.22 36.7 71.6 2 866 0.2 7.7 51.22 38.7 75.6 3 874 0.2 17.0 113.07 66.3 ± 1.0 58.6 ± 0.9 4 873 0.2 35.0 232.80 58.2 36.6 5 873 1.0 35.0 232.80 73.3 ± 1.2 31.5 ± 0.5 6 877 2.0 14.0 93.12 35.5 38.1 7 877 2.5 14.0 93.12 19.8 21.3 8 877 3.0 14.0 93.12 12.4 ± 0.2 13.3 ± 0.2

* Volume correction value of exhaust gas (25 ℃, atmospheric pressure)

Comparative Examples 1 to 4 were to investigate the decomposition conversion rate of H ₂ SO ₄ to SO ₂ , O ₂ when the sulfuric acid solution supply rate was changed while maintaining the reaction pressure at 0.2 atm (air pressure), and the feed rate was 7.7 g. When the temperature is lower than / min, the decomposition conversion rate is 71.6% and 75.6% depending on the temperature, which is close to the equilibrium conversion rate of 84.46% (0.2 atm and 850 ° C) and 86.68% (0.2 atm and 870 ° C). High value.

However, as the feed rate of sulfuric acid solution increased, the rate of sulfuric acid decomposition conversion drastically decreased. In particular, the sulfuric acid decomposition conversion rate was very low because the sulfuric acid evaporation did not proceed smoothly under high pressure. Although the conditions of Comparative Example 7 were closer to Example 2 than those between Examples 2 and 3, the sulfuric acid decomposition conversion rate was 21.3%, which was much lower than the median value of 70.7% of Example 2 and 48.3% of Example 3. Seemed. This is because one silicon carbide tube alone lacks the heat exchange area of the integrated reactor to cope with the evaporation, preheating, pyrolysis, and catalytic decomposition of sulfuric acid. In Examples 1 to 7, the sulfuric acid solution supplied in the lower silicon carbide tube was added immediately. In the case of Comparative Examples 1 to 8, in the case of Comparative Examples 1 to 8, after the sulfuric acid solution was accumulated at the silicon carbide center connection part and the lower part of the silicon carbide tube, evaporation occurred only when the temperature of the entire solution had risen to the evaporation temperature. It can be seen that it is lower than the evaporation temperature and the solution continues to accumulate.

1: sulfuric acid reservoir 2: sulfuric acid supply pump
3: vertically integrated silicon carbide sulfate reactor
4: granular catalyst layer
5: sulfate cracking furnace 6: gas-liquid separator
7: Pressure regulating valve 8: Dilute sulfuric acid trap
9: three-way valve 10: HI / I ₂ solution trap
11: dry gas meter 12: alkaline aqueous solution trap
13: vent 14: pressurized zone
21: Silicon Carbide Tube
22: inner tube (silicon carbide or quartz material)
23: sulfuric acid decomposition catalyst layer 24: silicon carbide central connection
25: Tube and central connector fastener (metal)
26: Precious Metal Lining Tube 27: Precious Metal Lining Tube Fastener
28: sulfuric acid inlet 29: sulfuric acid decomposition gas outlet
30: ring type aluminum liner
31: Bell type silicon carbide tube 32: Silicon carbide tube outer diameter
33: Silicon carbide tube bore 34: Silicon carbide tube skirt
35: silicon carbide center connection 36: sulfuric acid inlet
37: sulfuric acid decomposition gas outlet 38: gas rising path
39: Inner tube connector (threaded)
41: upper inner tube (silicon carbide or quartz material)
42: lower inner tube (silicon carbide or quartz material)
43: inner tube thread
44: sulfuric acid decomposition catalyst layer installed in the inner tube
45: sulfate decomposition catalyst layer installed outside the inner tube
46: catalyst bed support (silicon carbide material)
51: Bundle of vertically integrated silicon carbide sulfate reactor
52: upper heating block 53: lower heating block
54: sulfuric acid inlet 55: sulfuric acid decomposition gas outlet

Claims (16)

Bell-shaped upper tube made of silicon carbide;
Bell-shaped lower tube made of silicon carbide;
A center connection part of silicon carbide material connecting the upper tube and the lower tube; And
A vertically integrated silicon carbide sulfate decomposition reactor comprising: a fastening portion of a stainless steel material having an aluminum liner for fastening the upper tube and the lower tube to the central connection portion.
The central connection portion includes a sulfuric acid inlet, a sulfuric acid cracking outlet, a supply passage, an outlet passage, and one or more gas ascending passages, wherein the sulfuric acid inlet is connected to the supply passage, and the sulfated gas outlet is connected to the outlet passage. Vertically integrated silicon carbide sulfuric acid decomposition reactor, characterized in that connected. The method of claim 1,
The sulfuric acid decomposition reactor further includes an upper inner tube and a lower inner tube, each of which is open at both ends in the tubes of the upper tube and the lower tube, respectively.
One end of the upper inner tube is connected to the discharge passage, one end of the lower inner tube is vertically integrated silicon carbide sulfate decomposition reactor, characterized in that connected to the supply passage. The method of claim 2,
The sulfuric acid decomposition gas outlet is located at an upper side of the central connection, and the sulfuric acid inlet is located at a lower side of the central connection;
The discharge passage includes a vertical discharge passage and a horizontal discharge passage, wherein the vertical discharge passage is connected to the horizontal discharge passage from the center of the upper surface of the central connection portion toward the lower side along the central axis of the central connection portion. Connected to the vertical discharge passage from the sulfuric acid decomposition gas outlet toward the center axis in a horizontal direction;
The supply passage includes a vertical supply passage and a horizontal supply passage, wherein the vertical supply passage is connected to the horizontal supply passage from the center of the lower surface of the center connection portion toward the upper side along the central axis of the central connection portion. Connected to the vertical feed channel from the sulfuric acid inlet to the central axis in a horizontal direction;
The at least one gas rise passage penetrates the central connection portion vertically so as not to meet the horizontal discharge passage and the horizontal supply passage at a position farther from the central axis than the vertical supply passage and the vertical discharge passage. Sulfuric Acid Reactor. The method of claim 2,
The upper portion of the upper tube further comprises a granular sulfate decomposition catalyst layer, wherein the granular sulfate decomposition catalyst layer is installed inside the upper end of the upper inner tube, or between the upper inner tube and the upper tube vertical Integrated Silicon Carbide Sulfuric Acid Reactor. The method of claim 1,
And the sulfuric acid inlet and the sulfuric acid decomposition gas outlet are connected to a sulfuric acid inlet pipe and a decomposition gas discharge pipe, respectively. The method of claim 2,
Vertically integrated silicon carbide sulfate decomposition reactor, characterized in that the material of the upper inner tube and the lower inner tube is quartz or silicon carbide. The method of claim 2,
And a piece of a quartz tube or a piece of ceramic tube filled with a Raschig ring in between the upper tube and the upper inner tube. The method of claim 2,
And a piece of a quartz tube or a piece of ceramic tube filled with a Raschig ring in between the lower tube and the lower inner tube. Sulfuric acid decomposition apparatus for producing sulfur dioxide and oxygen by decomposing sulfuric acid, including the vertically integrated sulfuric acid decomposition reactor according to claim 1. The method of claim 9,
The sulfuric acid decomposition device is a sulfuric acid decomposition device characterized in that the vertical integral sulfuric acid decomposition reactor connected to a plurality of bundles. The method of claim 9,
And a heating furnace capable of heating the upper tube and the lower tube of the sulfate decomposition reactor to different temperatures. The method of claim 9,
A sulfuric acid supply pump for controlling the supply rate of sulfuric acid supplied to the sulfuric acid decomposition reactor and a pressure control valve for controlling the pressure in the sulfuric acid decomposition reactor by adjusting the discharge rate of the sulfuric acid decomposition gas discharged from the sulfuric acid decomposition reactor Sulfuric acid decomposition device. The method of claim 9,
And a rare sulfuric acid solution trap for trapping SO ₃ and H ₂ O discharged from the sulfate decomposition reactor to separate gases SO ₂ and O ₂ from SO ₃ and H ₂ O. In the sulfuric acid decomposition method for producing sulfur dioxide and oxygen using the sulfuric acid decomposition device according to claim 9,
(a) supplying a sulfuric acid solution to the lower tube through the lower inner tube, heating the temperature of the lower tube to 350-700 ° C. to evaporate the sulfuric acid and pyrolyze into SO ₃ and H ₂ O;
(b) heating the temperature of the upper tube to 700-1000 ℃ pyrolysis and the undissolved sulfate in the step (a) with additional SO ₃ and H ₂ O, the SO ₃ and H ₂ O in the catalyst layer provided on the upper tube Decomposing into SO ₂ and O ₂ ; And
(C) sulfuric acid decomposition method comprising the step of discharging the decomposed SO ₂ and O ₂ through the upper inner tube. 15. The method of claim 14,
The step (a) further comprises the step of adjusting the rate of supplying sulfuric acid solution, sulfuric acid decomposition method characterized in that for supplying the sulfuric acid solution at 5-35 g / min. 15. The method of claim 14,
The step (c) further comprises the step of adjusting the pressure of the sulfuric acid decomposition reactor by controlling the discharge rate of the decomposed SO ₂ and O ₂ , the pressure of the sulfuric acid decomposition reactor is characterized in that the sulfuric acid is 0.2-5 atmosphere Decomposition method.

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