JP2014024708A - Piping used for heat exchange system and heat exchange system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means to rapidly avoid failure which is produced by contamination of a heat transfer medium composed of a molten salt by a process fluid in a heat exchange system.SOLUTION: Piping 7: is used in a heat exchange system to conduct heat exchange between a process fluid, which includes at least one of hydrogen chloride and chlorine, and a heat transfer medium, which is composed of a molten salt and circulates in a heat transfer medium flow channel, without directly bringing them into contact with each other; has an inner diameter of 70 mm or more; and makes a gas phase in the heat transfer medium flow channel and the atmosphere communicate with each other.

Description

  The present invention relates to a pipe used in a heat exchange system between a process fluid and a heat medium, and more particularly to a pipe useful when mixing of a process fluid on the heat medium side is detected. Moreover, this invention relates to the heat exchange system provided with the said piping.

  A system for producing chlorine by using hydrogen chloride gas as a raw material and reacting it with oxygen in the gas phase in the presence of a catalyst (hydrochloric acid oxidation system), for example, a raw material gas containing hydrogen chloride and oxygen in the presence of a catalyst. A reactor to be reacted, a quenching tower for obtaining chlorine by absorbing unreacted hydrogen chloride by removing it by water or hydrochloric acid water by bringing the reaction gas after the reaction into contact with water or hydrochloric acid water, and the like are provided. The reaction in the reactor is usually carried out under high pressure and high temperature and is exothermic.

  The hydrochloric acid oxidation system heats the raw material gas in advance, removes reaction heat generated from the reaction gas in the reactor, and cools the reaction gas after the reaction. A heat exchange system is provided for heating, removing heat or cooling a process fluid (raw gas, reaction gas during reaction, reaction gas after reaction) containing hydrogen chloride or chlorine.

  In such a heat exchange system for heating, heat removal or cooling, heat exchange is usually performed through a heat conductor without directly contacting the process fluid and the heat medium. As the heat medium, for example, molten salt, steam, hot water, cold water, or the like is used according to the temperature of the process fluid.

  In such a heat exchange system, when a problem occurs in the flow path through which the process fluid flows and the process fluid is mixed into the heat medium side, it is necessary to quickly detect this. Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-83833) describes a method for detecting mixing of a process fluid by detecting a gas component generated by contact between a heat medium and the mixed process fluid. Yes. Patent Document 2 (Japanese Patent Laid-Open No. 2012-47616) describes detecting the mixing of a process fluid on the heat medium side by detecting oxygen gas at a gas phase portion in the heat medium flow path. .

JP 2003-83833 A JP 2012-47616 A

  In the heat exchange system, when the process fluid is mixed into the heat medium side, the pressure in the gas phase part in the heat medium flow path increases, or a gas containing hydrogen chloride or chlorine is present in the gas phase part in the heat medium flow path. The problem of being included occurs.

  An object of the present invention is to provide means capable of quickly avoiding problems caused by mixing of a process fluid on the heat medium side made of molten salt in a heat exchange system. And Moreover, it aims at providing the heat exchange system provided with the means which can avoid this malfunction rapidly.

  The present invention is used for a heat exchange system in which heat exchange is performed without direct contact between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt that circulates in the heat medium flow path. The piping has an inner diameter of 70 mm or more and can communicate the gas phase portion in the heat medium flow path with the atmosphere.

  The present invention also provides a heat exchange system for exchanging heat without directly contacting between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt that circulates in the heat medium flow path. This is a pipe that can communicate with a gas phase portion in a heat medium flow path and a harmless facility that renders hydrogen chloride and / or chlorine harmless.

  The detoxification facility is preferably configured to detoxify hydrogen chloride and / or chlorine and release it into the atmosphere. Moreover, it is preferable that the said piping which can connect the gaseous-phase part in a heat-medium flow path and the harmless installation has the internal diameter of 70 mm or more.

  The present invention also relates to a heat exchange system for exchanging heat without directly contacting between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt, and circulating the heat medium A heat exchange system including a heat medium flow path and a pipe having an inner diameter of 70 mm or more and capable of communicating a gas phase portion in the heat medium flow path with the atmosphere.

  Further, the present invention is a heat exchange system for performing heat exchange between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt without directly contacting the heat transfer medium. The heat exchange system includes a heat medium flow path, a gas phase portion in the heat medium flow path, and a pipe capable of communicating with a harmless facility that renders hydrogen chloride and / or chlorine harmless.

  According to the present invention, in the heat exchange system, even if the process fluid is mixed into the heat medium side made of the molten salt, the pressure increase in the gas phase portion in the heat medium flow path, the hydrogen chloride or It is possible to quickly avoid problems such as containing gas containing chlorine.

It is the schematic which shows the heat exchange system which is one Embodiment of this invention. It is a figure which shows the simulation result of the time-dependent change of the pressure of the gaseous-phase part of a molten salt storage drum when a malfunction arises in the heat exchange system shown in FIG.

  The present invention relates to a heat exchange system for performing heat exchange without direct contact between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of a molten salt that circulates in the heat medium flow path, and The present invention relates to a pipe used in the heat exchange system and capable of communicating a gas phase portion in a heat medium flow path and the atmosphere.

  The process fluid means a gas or liquid subjected to a heat exchange process with a heat medium or a mixture thereof. The heat exchange process in the present invention may be accompanied by a reaction of the process fluid as well as heat exchange between the process fluid and the heat medium, or may be a process in which only heat exchange is performed. In the former case, the process fluid is a raw material, intermediate, product, by-product of the reaction, or a mixture of two or more thereof.

  The heat exchanger used in the heat exchange process between the process fluid and the heat medium is not particularly limited as long as the process fluid and the heat medium exchange heat through a partition such as a tube or a flat plate. Heat exchange reactors such as multitubular catalyst-filled reactors when the heat exchange process involves reaction of process fluids, multitubular cylindrical heat exchangers that are simply bulkhead heat exchangers that perform heat exchange, plate type A heat exchanger, a spiral heat exchanger, a block heat exchanger, etc. are mentioned. Examples of the heat exchange reactor include a multi-tube fixed bed catalyst reactor including a plurality of reaction tubes filled with an oxidation catalyst and performing a gas phase oxidation reaction with the fixed bed catalyst.

The process fluid is not particularly limited as long as it contains at least one of hydrogen chloride and chlorine. As a preferred example of the process fluid involving a reaction, chlorine is produced by oxidizing hydrogen chloride gas with oxygen gas. Reaction shown in 1) (hydrochloric acid oxidation reaction):
2HCl + 1 / 2O ₂ → Cl ₂ + H ₂ O + 58.6 kJ / mol Formula (1)
And process fluids.

  The process fluid involving the reaction of Formula (1) is a raw material gas containing hydrogen chloride gas and oxygen gas; a chlorine gas as a product, and a product gas containing hydrogen chloride gas and oxygen gas as unreacted raw materials; or these Can be a mixture of The process fluid may contain an inert gas such as nitrogen, carbon dioxide, or argon in addition to the raw material gas and the product gas. In the reaction of formula (1), the theoretical molar amount of oxygen with respect to 1 mol of hydrogen chloride is 0.25 mol, but the oxygen gas exceeds the theoretical amount with respect to hydrogen chloride gas (for example, 0 mol with respect to 1 mol of hydrogen chloride). It is usual to use more than 25 moles and 2 moles or less. The hydrochloric acid oxidation reaction of formula (1) is an equilibrium reaction. In order to increase the hydrogen chloride conversion rate and increase the chlorine production rate, it is better that the reaction temperature is low, and the reaction heat is removed by a heat medium in order to bring out the performance of the catalyst used in the reaction.

In the present invention, the heat medium is composed of a molten salt (HTS), and a preferable molten salt is selected according to the temperature of the target process fluid. The molten salt (HTS) preferably contains nitrite (NaNO _{2 and the} like) and / or nitrate (NaNO ₃ , KNO _{3 and the} like), and from the viewpoint of handleability, the melting point thereof is preferably about 100 to 200. ° C. Specific examples of the molten salt preferably used include a composition (melting point 142 ° C.) composed of NaNO ₂ (40% by mass), NaNO ₃ (7% by mass) and KNO ₃ (53% by mass); NaNO ₂ (34% by mass) , NaNO ₃ (13 mass%) and KNO ₃ (53 mass%) (melting point 152 ° C.); NaNO ₂ (50 mass%) and KNO ₃ (50 mass%) (melting point 139 ° C.) It is.

Among them, as a heat medium used for heat exchange with the process fluid in the hydrochloric acid oxidation reaction, a molten salt composed of NaNO ₂ (50% by mass) and KNO ₃ (50% by mass) from the viewpoint of the reaction temperature of the process fluid, etc. Is preferably used.

  The heat medium flow path through which the heat medium flows includes a heat medium flow path (so-called jacket or the like) provided in a heat exchanger that performs heat exchange between the process fluid and the heat medium, and a heat medium tank that stores the heat medium; A heat exchanger (heater and / or cooler) for heating and / or cooling the medium; disposed between the heat exchanger in which heat exchange between the process fluid and the heat medium takes place and the heat medium tank; A buffer tank that performs fine adjustment of the heat medium temperature; a heater and / or cooler that adjusts the temperature of the heat medium in the buffer tank; a pipe that connects these devices; a pump that circulates the heat medium, etc. A heat medium circulation channel that is connected to the heat medium flow channel, and a pipe for introducing an inert gas such as nitrogen, carbon dioxide, and argon into the heat medium circulation flow channel and the heat medium flow channel. It connects the phase portion and the atmosphere or detoxification facilities, including a pipe for discharging the gas phase of the gaseous heating medium flow path to the outside.

  In the present invention, by providing a pipe for discharging the gas in the gas phase portion in the heat medium flow path to the outside, even if the process fluid is mixed into the heat medium, the mixed process fluid is exposed to the outside. Thus, it is possible to quickly avoid problems such as an increase in pressure in the heat medium flow path and hydrogen chloride or chlorine contained in the gas phase portion in the heat medium flow path. Even when the process fluid is mixed in the heat medium, from the viewpoint of preventing an increase in pressure in the heat medium flow path, the gas phase portion in the heat medium flow path and the atmosphere or detoxification equipment in the present invention Is preferably 70 mm or more, and more preferably 80 mm or more. In the case where a detoxification facility is provided, it is preferable that hydrogen chloride and / or chlorine be detoxified and released to the atmosphere. With such a configuration, even when the process fluid is mixed into the heat medium, hydrogen chloride and / or chlorine contained in the process fluid can be rendered harmless and released to the atmosphere.

The sealing of the heat medium flow path by introduction of the inert gas prevents the heat medium from deteriorating and the reaction of the following formula (2) due to the presence of air in the heat medium flow path:
NaNO ₂ + 1 / 2O ₂ → NaNO ₃ +111.7 kJ / mol Formula (2)
To prevent the occurrence of

When the reaction of the formula (2) occurs, NaNO ₃ is generated, whereby the melting point of the molten salt rises to about 300 ° C. or more, and there is a possibility that it is blocked at a low temperature part. Even if the gas phase part of the heat medium flow path is sealed with an inert gas such as nitrogen gas, the process fluid used in the hydrochloric acid oxidation reaction contains oxygen gas. There is a possibility that the reaction of the formula (2) occurs. In the hydrochloric acid oxidation reaction, the pressure of the process fluid is usually operated higher than the pressure of the molten salt. There is a possibility that the reaction of formula (2) occurs by mixing into the salt side and coming into contact with the molten salt. Furthermore, since the process fluid contains hydrogen chloride gas and / or chlorine gas, when the process fluid is mixed into the molten salt side, the chemical reaction of the following formula (3) and / or formula (4):
NaNO ₂ + HCl + 1 / 4O ₂ → NaCl + 1 / 2H ₂ O + NO ₂ +47.9 kJ / mol Formula (3)
NaNO ₂ + 1 / 2Cl ₂ → NaCl + NO ₂ +19.3 kJ / mol Formula (4)
May occur.

  In addition, when using a commercially available molten salt as a molten salt, what does not contain an organic anti-caking agent etc. is normally employ | adopted. Hereinafter, the present invention will be described in more detail by showing specific embodiments.

[Heat exchange system]
FIG. 1 is a schematic diagram showing a heat exchange system according to an embodiment of the present invention. In the heat exchange system shown in FIG. 1, chlorine is produced by oxidizing hydrogen chloride with oxygen. The heat exchange system shown in FIG. 1 includes a multitubular fixed bed catalyst reactor 1 that is a heat exchanger and a molten salt storage drum 4 that stores molten salt. The multitubular fixed bed catalyst reactor 1 includes a plurality of reaction tubes (not shown) that are process fluid flow paths and a jacket (not shown) that is a heat medium flow path. The molten salt storage drum 4 includes a gas phase portion 42 and a liquid phase portion 41 made of a molten salt.

  In the heat exchange system shown in FIG. 1, the process fluid flow path includes a pipe 21, a process fluid flow path in the multi-tube fixed bed catalyst reactor 1, and a pipe 22. The raw material gas is guided to the multitubular fixed bed catalyst reactor 1 through the pipe 21, and the hydrochloric acid oxidation reaction in the process fluid and the heat exchange between the process fluid and the heat medium are performed in the multitubular fixed bed catalyst reactor 1. Thereafter, the reaction product gas is led to the outside of the multitubular fixed bed catalyst reactor 1 through the pipe 22 and sent to the next step.

  The heat medium flow path of the heat exchange system shown in FIG. 1 includes a first circulation path, a second circulation path, and a third flow path. The first circulation path includes a molten salt storage drum 4, a pipe 31 and a pipe 32 that connect the molten salt storage drum 4 and the multitubular fixed bed catalyst reactor 1, and heat in the multitubular fixed bed catalyst reactor 1. It is comprised from the medium flow path and the piping 33 which connects the multitubular fixed bed catalyst reactor 1 and the molten salt storage drum 4. The pipe 31 includes a pump 8 for circulating the molten salt. In the first circulation path, when the pump 8 is operated, the molten salt in the molten salt storage drum 4 is guided to the heat medium flow path in the multitubular fixed bed catalyst reactor 1 through the pipe 31 and the pipe 32. After the heat exchange in the multitubular fixed bed catalyst reactor 1, the pipe is guided to the molten salt storage drum 4 through the pipe 33.

  The second circulation path includes the molten salt storage drum 4, the pipe 31, and the pipe 34 including the cooler 6. In the second circulation path, when the pump 8 is operated, the molten salt in the molten salt storage drum 4 flows through the pipe 31 and the pipe 34 and is led to the molten salt storage drum 4 again. In the pipe 34, the molten salt in the pipe 34 is cooled by the cooler 6. Accordingly, it is possible to adjust the temperature of the molten salt by cooling the molten salt whose temperature has been increased by heat exchange in the first circulation path through the second circulation path.

  Although the configuration of the cooler 6 is not particularly limited, the cooler 6 shown in FIG. 1 is supplied with water via a pipe 61, and water is changed to steam by recovering the heat of the molten salt. Steam generator from which steam is discharged. The steam discharged from the cooler 6 can be used, for example, for heating a process fluid supplied to the reaction.

  The third flow path is composed of a pipe 7 capable of communicating the gas phase part 42 of the molten salt storage drum 4 with a detoxification facility for detoxifying hydrogen chloride and / or chlorine. Gas is sent to the outside. By having the piping 7, even when the process fluid is mixed in the heat medium, it is possible to prevent the pressure in the gas phase portion in the heat medium flow path from increasing, and hydrogen chloride or chlorine It is possible to prevent the occurrence of a problem that gas containing gas is contained. In addition, since the pipe 7 is connected to the detoxification facility, even when the process fluid is mixed into the heat medium, hydrogen chloride and chlorine contained in the process fluid can be detoxified and discharged.

  The pipe 7 is preferably provided so as to be able to communicate with the gas phase portion 42 and the atmosphere, and therefore, the detoxification facility is preferably connected to the atmosphere. It is further preferable that the pipe 7 has a configuration in which the gas phase portion 42 and the atmosphere are always in communication. Therefore, when the pipe 7 includes a valve, the valve is always open, and the harmless equipment is always in the atmosphere. The open state is preferred. The inner diameter of the pipe 7 is preferably 70 mm or more, and more preferably 80 mm or more. When the inner diameter of the pipe 7 is 70 mm or more, even if a process fluid is mixed in the heat medium flow path, it is possible to suppress an increase in pressure in the gas phase portion in the heat medium flow path.

The heat medium flow path includes a gas detector 5 in the molten salt storage drum 4 for detecting gas in a gas phase portion in the heat medium flow path. Although the configuration of the gas detector 5 is not limited, for example, oxygen gas or NO _x gas generated by the reactions of the formulas (3) and (4) is detected, thereby mixing the process gas into the heat medium. It is preferable that the configuration be detectable.

  The process fluid supplied to the multi-tube fixed bed catalyst reactor 1 through the pipe 21 contains hydrogen chloride gas and oxygen gas, or when recycling unreacted oxygen to the reaction system, hydrogen chloride gas, oxygen gas and chlorine. Contains gas. On the other hand, the process fluid coming out of the multi-tube fixed bed catalyst reactor 1 contains chlorine gas, hydrogen chloride gas, oxygen gas, and water vapor. In particular, the hydrochloric acid oxidation reaction process is operated under conditions that prevent water vapor from condensing and hydrogen chloride gas from becoming hydrochloric acid water.

  The material of the equipment used in the heat exchange system of FIG. 1 is not particularly limited, but nickel is usually used for a portion in contact with the process gas, for example, a reaction tube of the multi-tubular fixed bed catalytic reactor 1, and molten salt Usually, carbon steel is used for the portion in contact with, for example, the jacket of the multi-tubular fixed bed catalytic reactor 1 and the molten salt storage drum. The reaction temperature is preferably controlled and the reaction heat is removed so that the reaction temperature does not exceed about 450 ° C. Note that when the process fluid is cooled to condense the hydrochloric acid water, tantalum, Teflon (registered trademark), carbon, or the like is used for the portion in contact with the hydrochloric acid water.

  Examples of the catalyst used in the hydrochloric acid oxidation reaction process include, but are not limited to, a ruthenium oxide catalyst and a chromium oxide catalyst. In the hydrochloric acid oxidation reaction process, a measuring means for constantly measuring the temperature of the catalyst layer may be provided, and the temperature of the catalyst layer can be controlled by such a measuring means so that the optimization of the reaction and the temperature runaway can be detected at an early stage. The reaction temperature, reaction pressure, and catalyst layer temperature control method in the multitubular fixed bed catalyst reactor 1 are not particularly limited.

  In the following experiment, in the hydrochloric acid oxidation process performed using the heat exchange system shown in FIG. 1, a simulation is performed when the process fluid is mixed into the molten salt side, and the gas phase portion 42 in the molten salt storage drum 4 in the simulation is obtained. The change with time of the pressure was determined. In this simulation, a plurality of types of pipes 7 having different inner diameters were used for the pipes 7 that connect the gas phase part 42 of the molten salt storage drum 4 and the detoxifying equipment.

  In this simulation, the configuration and conditions of each element were determined on the assumption that the chlorine production process is 100,000 tons of chlorine per year. The number of reaction tubes of the multi-tubular fixed bed catalyst reactor 1 is proportional to the chlorine production amount. In this simulation, the number of reaction tubes is set to 10,000, which is a normal number when the chlorine production amount is 100,000 tons per year. The inner diameter of the reaction tube of the multitubular fixed bed catalyst reactor 1 is usually 18 mm to 25 mm, and the length of the reaction tube is 4 m to 6 m. These values are constant regardless of the chlorine production. In this simulation, the inner diameter of each reaction tube was 21 mm and the length was 5.7 m.

The capacity of the molten salt storage drum 4 is proportional to the amount of chlorine produced. In this simulation, the capacity of the molten salt storage drum 4 is within the range of conditions normally employed when the chlorine production is 100,000 tons per year. the capacity 2.94m ^3, the capacity of the gas phase portion was 0.8m ^3. The pressure of the raw material gas and the pressure of the reaction product gas are substantially constant without depending on the chlorine production amount. Usually, the pressure of the raw material gas is 0.2 to 0.5 MPaG, and the pressure of the reaction product gas is 0.1 to 0.4 MPaG. In this simulation, the pressure of the process fluid was 0.413 MPaG.

  The initial pressure on the molten salt side, that is, the pressure before the process fluid is mixed into the molten salt side, is usually almost constant regardless of the chlorine production. Usually, the pressure of the molten salt entering the jacket of the multitubular fixed bed catalyst reactor 1 is 0.1 MPaG, and the pressure of the molten salt exiting from the jacket of the multitubular fixed bed catalyst reactor 1 is 0.05 MPaG. In this simulation, the initial pressure of the molten salt in the jacket of the multitubular fixed bed catalyst reactor 1 was 0.063 MPaG.

  The inner diameter and length of the pipe 33, which is a molten salt flow path, are substantially proportional to the chlorine production. In this simulation, when the chlorine production amount is 100,000 tons per year, the condition is normally used, that is, the inner diameter of the pipe 33 is 400 mm and the length is 40 m. Further, in FIG. 1, the length of the pipe 7 connecting the gas phase portion 42 of the molten salt storage drum 4 and the detoxification equipment for detoxifying hydrogen chloride gas and chlorine gas is substantially proportional to the chlorine production amount. In the simulation, it was set to 60 m, which is within the range of conditions normally employed when the chlorine production is 100,000 tons per year. The pressure loss of the detoxification equipment is almost proportional to the chlorine production, and was set to 0.05 MPa in this simulation.

  There are various possible causes for the mixing of the process fluid on the molten salt side. In this simulation, one hole or multiple holes are generated in the reaction tube, and the total area of the generated holes is the inner diameter area of one reaction tube. Assuming the case where the same problem occurs. For example, a case where one reaction tube is cut perpendicular to the wall surface is also included in the problem assumed here. The jetting speed of the process fluid from the generated hole to the molten salt side was 370 m / s, which is the speed of sound.

  Usually, in the hydrochloric acid oxidation reaction, 1 mol of oxygen is supplied to 2 mol of hydrogen chloride, and the conversion rate of hydrogen chloride is 85%. In this case, the composition of the process fluid at the inlet and outlet of the multi-tube fixed bed catalytic reactor 1 is as shown in Table 1 below.

  In this simulation, the following composition, which is an average value of the composition at the reactor inlet and the composition at the reactor outlet, was used as the composition of the process fluid mixed on the molten salt side.

Hydrogen chloride concentration (mol%) = 40,
Oxygen concentration (mol%) = 20,
Chlorine concentration (mol%) = 20,
Water vapor concentration (mol%) = 20.

  Further, when the process gas is mixed on the molten salt side, the reaction rate of the reactions of the above formulas (2), (3), and (4) is considered as the reaction between the molten salt and the process gas.

  FIG. 2 shows the molten salt storage drum 4 in the case where a hole is formed in the reaction tube due to a malfunction as described above (elapsed time 0 seconds from the occurrence of mixing), and the process fluid continues to be mixed into the molten salt side from the generated hole. 1A and 1B, when the pipe 7 is not provided in the heat exchange system of FIG. 1 (A), the inner diameter of the pipe 7 of the heat exchange system of FIG. 1 is 25 mm (B), 40 mm (C ), 50 mm (D), 80 mm (E), and 100 mm (F).

  As shown in FIG. 2, when the pipe 7 is not provided (A), that is, when the molten salt storage drum 4 is sealed, the pressure of the gas phase portion 42 of the molten salt storage drum 4 is 1 MPaG in 23 seconds. Rose to. On the other hand, it was found that when the inner diameter of the pipe 7 was 80 mm or 100 mm, there was almost no pressure increase in the gas phase part 42 of the molten salt storage drum 4.

  1 multi-tube fixed bed catalyst reactor, 21, 22 piping, 31, 32, 33, 34 piping, 4 molten salt storage drum, 5 gas detector, 6 cooler, 61, 62 piping, 7 piping, 8 pump.

Claims (6)

Used in a heat exchange system that performs heat exchange without direct contact between a process fluid containing at least one of hydrogen chloride and chlorine, and a heat medium that is circulated in the heat medium flow path and is made of a molten salt;
A pipe having an inner diameter of 70 mm or more and capable of communicating the gas phase portion in the heat medium flow path with the atmosphere. Used in a heat exchange system that performs heat exchange without direct contact between a process fluid containing at least one of hydrogen chloride and chlorine, and a heat medium that is circulated in the heat medium flow path and is made of a molten salt;
A pipe capable of communicating the gas phase portion in the heat medium flow path with the detoxifying equipment for detoxifying the hydrogen chloride and / or the chlorine.   The piping according to claim 2, wherein the detoxification facility detoxifies the hydrogen chloride and / or the chlorine and releases it to the atmosphere.   The piping according to claim 2 or 3, wherein the inner diameter is 70 mm or more. A heat exchange system for performing heat exchange without directly contacting between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt,
A heat medium flow path for circulating the heat medium;
A heat exchange system having an inner diameter of 70 mm or more and a pipe capable of communicating a gas phase portion in the heat medium flow path with the atmosphere. A heat exchange system for performing heat exchange without directly contacting between a process fluid containing at least one of hydrogen chloride and chlorine and a heat medium made of molten salt,
A heat medium flow path for circulating the heat medium;
A heat exchange system comprising a gas phase section in the heat medium flow path and piping capable of communicating with the hydrogen chloride and / or detoxification equipment for detoxifying the chlorine.

Images