DE2905585A1 - PROCESS FOR SEPARATION OF THE HYDROGEN ISOTOPES H, D, T IN ORDER TO SELECTIVELY REMOVE INDIVIDUAL ISOTOPES FROM A MIXTURE - Google Patents

Description

Gebr. Sulzer AG P 5303 / Sd / hj

Process for the separation of the hydrogen isotopes H, D, T in order to selectively remove individual isotopes from a mixture.

The invention relates to a method for separating the hydrogen isotopes H, D, T, to selectively remove individual isotopes from a mixture, the separation by a catalytic Exchange between oxides of the hydrogen isotopes and the gaseous hydrogen isotopes with subsequent low-temperature distillation is brought about.

The above occurs when operating nuclear facilities Problem with tritium or hydrogen from those used in such systems as a moderator or coolant heavy water needs to be removed.

From FR-PS 1,526,867 it is known, for example, for work-up of heavy water containing tritium and hydrogen, that heavy water with a worked up deuterium gas in the gas phase in the presence of a catalyst in chemical reaction, with tritium and hydrogen out of their oxides to a certain extent through exchange in the deuterium gas. The deuterium gas is then by cryogenic distillation into the individual Components separated.

This procedure has the following major disadvantage:

The hydrogen isotope oxides are found in the isotope exchange and the hydrogen isotopes mixed with one another in the gas phase and can only go through the reaction phase in cocurrent be moved.

After the exchange has taken place in the reaction zone, the hydrogen isotope oxides become separated from the hydrogen isotopes by condensation.

The exchange reaction between the hydrogen isotope oxides and hydrogen isotopes can optionally be carried out several times in succession, after each Exchange zone again a phase separation must take place. In this way, a countercurrent can be achieved overall. This arrangement of several stages is extremely complex in terms of both apparatus and process technology. For example, the The proportion of hydrogen and tritium in heavy water only increases 1/3 will be lowered. A decrease to 1/10 or 1/100 would be desirable in many cases, but is justifiable Effort not possible.

In this case, the hydrogen oxides leave the treatment process as processed heavy water, while that enriched with tritium and hydrogen in the exchange stages Deuterium stream is broken down into its hydrogen isotopes in a low-temperature distillation plant. The separated one Deuterium is returned to the isotope exchange process and deuterium is lost through the addition of fresh deuterium added.

In another known method relating to the invention, as is known e.g. from CA-PS 1,014,525

909042/0622

290 ^ 585

the liquid hydrogen isotope oxides for exchange in countercurrent to the gaseous hydrogen isotopes via a water-insensitive, Two-phase countercurrent enabling catalyst to be performed. Such a catalyst is for example known from US-PS 3,981,976.

A major disadvantage of such a process, however, is that at the lower end of the exchange column high T content a large part of the hydrogen to be processed isotoponoxide by suitable methods, e.g. by electrolytic decomposition, which has to be broken down into hydrogen isotopes. Disadvantageous for this with the countercurrent exchange process coupled electrolytic decomposition process are the required large operating content of the plant as well as high requirements in terms of material technology. Another disadvantage is that at the top of the exchange column a large part of the hydrogen isotopes again must be converted into oxides in order to be fed back into the countercurrent exchange process.

The invention is based on the object of avoiding the above-mentioned disadvantages of the known methods described above, i.e. in a more economical way than previously in a procedural manner Respect to enable a separation of the hydrogen isotopes H, D, T, with the aim of a mixture selectively remove individual isotopes.

The solution to this problem is, according to the invention, that the catalytic exchange in the presence of an opposite resistant to the liquid oxides of the hydrogen isotopes Catalyst takes place in countercurrent between liquid oxides of the hydrogen isotopes and the gaseous hydrogen isotopes.

909842/0622

BATH ORIGINAL

The catalyst used can advantageously be a hydrophobic catalyst such as that used, for example, from that already mentioned U.S. Patent 3,981,976 is known.

The invention is explained below with reference to an embodiment shown schematically in a flow diagram.

A plant (not shown), e.g. a nuclear reactor, is converted into a hydrogen isotope oxide to be worked up through a line 1, E.g. heavy water containing tritium is introduced into an isotope exchange tower 2. This one contains one hydrophobic catalyst in solid form. In countercurrent to this, a gaseous hydrogen isotope flow, e.g. from an other hydrogen isotopes depleted deuterium exist can, fed through a line 3 in the exchange tower. The hydrogen isotope gas stream is enriched with tritium. The hydrogen isotope oxide depleted in the hydrogen isotope, e.g. heavy water depleted in tritium is returned through a line 4, e.g. to a nuclear reactor. The one in the isotope exchange tower Enriched hydrogen isotope gas stream is from the top of the tower through a line 5 into a cryogenic distillation plant 6 known execution initiated. In the column there is a separation of the lighter and less volatile hydrogen isotopes. For example, will at the top of the column hydrogen through a line 7 and on Tritium removed from the bottom through a line 8. The radioactive tritium is then stored or in a manner not shown fed to another further use.

The hydrogen isotope freed from the remaining hydrogen isotopes, e.g. Deuterium, is fed into the exchange tower through line 3 2 returned. The back to exchange tower 2

909842/0622

BATH ORIGINAL

outgoing depleted deuterium is supplemented by supplying fresh depleted deuterium through a line 9 to the extent that how easily and hardly volatile fractions are withdrawn from the cycle.

With the invention, for example, the content of tritium in a heavy water stream can be reduced to 1/10 to 1/100.

9098 ^ 2/0622

Claims (1)

Gebr. Sulzer AG P 5303 / Sd / hj Claim Process for the separation of the hydrogen isotopes H ,. D, T, um
selectively remove individual isotopes from a mixture,
the separation by a catalytic exchange between oxides of the hydrogen isotopes and the gaseous ones
Hydrogen isotopes is brought about with subsequent low-temperature distillation, 'characterized in that the catalytic exchange under
The presence of a catalyst which is resistant to the liquid oxides of the hydrogen isotopes takes place in countercurrent between liquid oxides of the hydrogen isotopes and the gaseous hydrogen isotopes.