JPS6249936A - Infrared laser reactor - Google Patents

Abstract

PURPOSE:To improve the productivity of isotope sepn. by improving the utilizing efficiency of light. CONSTITUTION:A hollow IR waveguide 3 which is mounted with a cooling jacket 5 and is connected at the other end part 8 thereof to a gaseous raw material circulator 10 via a lead wire 9 is installed in a gas vessel 1. The waveguide 3 is so positioned that the condensed incident IR laser light from a window of a long focus lens 2 for an IR laser provided to the vessel 1 is transmitted in the waveguide. As a result, even the laser of low output is satisfactorily usable and since the economicity of the laser is improved, the total cost of the device is reduced. The cooling of the waveguide 3 only is required and the ratio at which the waveguide 3 occupies in the vessel 1 is small. The economicity of the cooling is thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a reactor for causing a chemical reaction using an infrared laser.

[Prior art]

Chemical reactions using infrared lasers are being applied to the isotopic separation of 'lC and JO8i, and are replacing conventional separation methods using chemical exchange and electromagnetic methods.

The most important problem with such laser-based isotope separation methods is how to improve productivity, and in order to solve this problem, various improvements have been made to the laser light source, the reaction system, etc.

For example, a pulsed laser is used as the laser,
Efforts are being made to achieve higher output, higher repetition rate, and shorter pulses.

In addition, in reaction systems, the search for separation work materials with excellent separation efficiency is underway.

Compared to these, the development of reactors has lagged behind, and infrared laser reactors require a beam of light with high energy density for the reaction, and since normal lasers do not have enough power, the light must be focused.

Therefore, usually a long focal length lens is used or the light is further reflected.

However, such light focusing methods have poor light utilization efficiency;
A considerable amount of light was wasted, and a more efficient reactor was desired.

[Purpose of the invention]

An object of the present invention is to provide an infrared laser reactor that dramatically improves the productivity of isotope separation by increasing the efficiency of light utilization.

[Structure of the invention]

The infrared laser reactor of the present invention which achieves the above object has a gas container provided with a window consisting of a long focal length lens for infrared laser, and a hollow space provided with a cooling jacket such that the opening end is located near the focal point of the lens. The present invention is characterized in that an infrared waveguide is installed within the container, and the other end of the hollow infrared waveguide is connected to a source gas circulation device provided within the gas container.

The basic configuration of the infrared laser reactor of the present invention will be explained below with reference to the drawings.

In FIG. 1, a gas container 1 is provided with a window for a long focal length lens 2 for an infrared laser.

Here, as the gas container 1, one that can withstand high vacuum is used, and after being evacuated in advance to below 1 O-3), the raw material gas is supplied and adjusted to a predetermined operating pressure.

The operating pressure varies depending on the reaction, but is usually 0.1 to several 1
00 Torr, which prevents side reactions due to air inclusion.

In general, the lower the pressure inside the gas container 1, the better the separation coefficient (expressed by equation (2) described below) will be, but the yield will be lower.
The operating pressure is determined by taking both into consideration.

On the other hand, a hollow infrared waveguide 3 is installed inside the gas container 1,
The opening end 4 is located near the focal point of the lens 2.

This open end portion 4 becomes a light receiving portion for an infrared laser.

As a result, the infrared laser focused at the focal point is guided into the hollow infrared waveguide 3 from the open end 4.

Here, as the hollow waveguide 3, a glass tube or a metal tube with a high reflectivity for infrared laser is suitable, and waveguides made of lead glass, copper, or stainless steel are preferred because they are currently easily available.

The inner diameter of the waveguide 3 is selected depending on the laser output and the type of reaction system, but it is usually about several mm, while the length of the waveguide is long in order to increase the light utilization efficiency. It is more preferable, and about 1 to several meters is appropriate.

In addition, in order to reduce the incidence loss of infrared laser light,
It is preferable that the opening end portion 4 has a conical shape that gradually expands outward, so that the light receiving rate of incident light can be increased.

A cooling jacket 5 is attached to the hollow infrared waveguide 3, and a refrigerant inlet pipe 6 and a refrigerant discharge pipe 7 are provided to penetrate the gas container 1.

Cooling of the waveguide is performed by circulating a coolant, and the cooling temperature should be as low as the vapor pressure of the raw material gas allows, in particular as long as the raw material gas can exist in a gaseous state. (shown in equation (2)) can be increased.

The other end 8 of the hollow infrared waveguide 3 is connected to a source gas circulation device 10 via a lead pipe 9, and an outlet 11 of this circulation device 10 opens into the gas container 1.

The source gas circulation device 10 is one that can operate at low pressure and does not contaminate the reaction system, such as a diaphragm pump.

Such a circulation device 10 has the advantage of being able to forcibly draw the raw material gas supplied into the gas container into the waveguide and discharge it, thereby improving reaction efficiency.

Further, the gas container 1 includes a gas introduction pipe 12 for introducing raw material gas and a gas discharge pipe 13 for discharging reactants.
are provided for each.

Next, the functions of the infrared laser reactor of the present invention will be described.

In FIG. 1, a laser 15 oscillated from a laser oscillator 14 is focused near a focal point F by a window 2 of a long focal length lens for infrared laser, and enters a hollow infrared waveguide 3 from an open end 4. The light is guided and transmitted to the other end 9 while being repeatedly reflected within this waveguide.

On the other hand, a raw material gas is introduced into the gas container 1 from a gas introduction pipe 12, and a chemical reaction occurs with this raw material gas in the hollow infrared waveguide 3 by an infrared laser.

The reactants are discharged from the gas discharge pipe 13.

〔Effect of the invention〕

As described above, in the infrared laser reactor of the present invention, a hollow infrared waveguide is installed in a gas container, and light is incident and focused through the window of a long focal length lens for infrared laser provided in the gas container. The structure is extremely simple, as the infrared laser beam is simply transmitted through a hollow waveguide.

Moreover, since the focused laser is transmitted through a hollow infrared waveguide, high laser density is maintained, and the reaction yield can be improved by 5 to 10 times compared to the conventional focusing method. can.

In conventional isotope separation using laser light, efforts have been made primarily to improve laser performance, as described above, in order to improve productivity.

However, increasing the output, increasing the repetition rate, and shortening the pulse length are technically difficult, and even if they were achieved, high costs and shortened device life could not be avoided.

In contrast, in the reactor using the hollow infrared waveguide of the present invention, a low-output laser can be used, making it possible to increase the economic efficiency of the laser, thereby significantly reducing the total cost of the device. can.

In addition, even in cooling, which has a large effect on isotope separation efficiency, only the hollow infrared waveguide needs to be cooled, and
Since the hollow infrared waveguide occupies a small proportion of the gas container, the economic efficiency of cooling can also be improved.

Currently, chemical reactions using lasers are mostly limited to isotope separation, but in the future, their uniqueness will open up many applications such as purification of high-purity gases and synthesis of metals, ceramics, and ultrafine particles. are expected, and the reactor of the present invention can be used for these purposes as well.

Furthermore, the reactor of the present invention can be used in other wavelength ranges by selecting the material of the hollow infrared waveguide, for example, a waveguide with an aluminum or silicon carbide interior can be used in the ultraviolet range, and its application is possible. It is expected that the range will expand in the future.

Examples of the present invention will be shown below.

〔Example〕

Using the reactor shown in FIG. 1, C isotope separation was performed using a carbon dioxide gas pulse laser.

The specific contents of the reactor are as follows.

Capacity and material of the gas container: It is made of 60mm steel and has a lid on the top.

Window: Barium fluoride lens with a diameter of 40 mm and a focal length of 700 mm.

Hollow infrared waveguide...Made of lead glass (Nippon Electric Glass L)
29), length 600 mm, the light receiving part has a conical shape with an inner diameter of 8 mm at the tip and an inner diameter III+ at the rear end, and the outer wall of the tube is covered with aluminum foil.

Cooling jacket: Made of copper, cooled by ethanol circulation.The rear end of the hollow infrared waveguide is connected to the suction port of the diaphragm pump by a pressure tube.

The laser is a lateral atmospheric pressure type carbon dioxide gas pulse laser.
(DD-300, manufactured by Gentec, Canada), and irradiation was performed at an incident energy of 0.25 Joule/pulse, a pulse width of 125 nanoseconds, and a pulse repetition rate of 10 Hz.

As the raw material gas, difluoromonochloromethane (CH
F, CI, and Guiflon 22) manufactured by Daikin Industries were used.

The absorption of this gas is caused by C molecules (CHPCI) of 9.3~
9.4 μm, and 130 molecules are ~0.2 μm below that.
It is on the m long wavelength side.

Therefore, when irradiated with a laser wavelength of around 9.6 μm, C molecules react according to formula (1) and are separated and concentrated in the form of tetrafluoroethylene CF.

2 CHP, CI-CP, CF, + 2 HCI
(1) hv(9,6μff1) The boiling point of the produced C FiCF2 is -76.3°C, which is significantly different from -40.8°C of the raw material CllF2C1, so it can be separated by distillation.

In this example, the yield was determined directly by gas chromatography and the separation factor was determined by mass spectrometry.

Here, the separation coefficient β is defined by the following equation (2).

β= C13C/”C) After concentration/(”C/”C) Before concentration (2) The oscillation line of the carbon dioxide laser is 9P (22
) line (wavelength: 9.57 μm) to 9P (30) line (wavelength: 9.64 μm) and measured the yield and separation coefficient. The results are shown in FIGS. 2A and B.

That is, CHF, CI, and 50 Torr are sealed in a gas container,
Irradiation was performed at 10 Hz for 10 minutes at the above wavelength and an energy of 0.25 Joule/pulse.

The waveguide temperature at this time was -16°C.

Figure 2A shows the case with a waveguide, and Figure 2B shows the case where the waveguide is removed and focused.
2B) When irradiated with radiation (wavelength 9.62 μm), the separation factor is 60.
The yield of CP-YCF2 is 1 compared to the case without waveguide.
It is more than 0 times.

It is thought that the separation coefficient can be further improved by increasing the energy density and homogeneity of the laser beam.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic configuration of the infrared laser reactor of the present invention, Figure 2A is a diagram showing the relationship between the yield of CF and CF2 and the separation coefficient in the reactor of the present invention, and Figure 2B is a diagram showing the relationship between the yield and separation coefficient of CF and CF2 in the reactor of the present invention. cp□C when the hollow infrared waveguide is removed from the reactor of the present invention
It is a figure showing the relationship between the yield of F. and the separation coefficient. l・-gas container, 2-long focus lens for infrared laser,
3-.Hollow infrared waveguide, 4-.-Open end, 5-cooling jacket, 10-.-Source gas circulation device. Patent applicant Tatsu Todoroki, Director of the Agency of Industrial Science and Technology Designated agent Ryozo Hayami, Director of the Osaka Industrial Technology Research Institute, Agency of Industrial Science and Technology Figure 2 A CO, Laser oscillation line Figure 2 B CO, Laser oscillation line

Claims (1)

[Claims] A window made of a long focal length lens for infrared laser is provided in the gas container, and a hollow infrared waveguide having a cooling jacket is installed in the container so that the open end is located near the focal point of the lens, and the An infrared laser reactor, characterized in that the other end of the hollow infrared waveguide is connected to a source gas circulation device provided in the gas container.