NO123749B - - Google Patents

Description

Method for separating difficult-to-separate liquid mixtures.

As is known, mixtures of substances can

with a small difference in boiling point, e.g.

mixtures of homologous coal water substances

or isotopic mixtures or azeotropic

mixtures of substances with different chemical properties difficult or not separated by distillation.

It was now found that one can separate

such liquid mixtures in a simple way by

partial evaporation or partial condensation or by a combination of both

processes, when performing this operation

in the presence of layers of such solid bodies as

have large surfaces, whose infrared spectral space bands intersect the infrared spectral bands of only one of the components of

the liquid mixture.

In the presence of such a solid body

that component of the liquid mixture is held

which have infrared spectrum bands which

intersects the bands for the solid body in the increment

degree in the vapor state, regardless of the boiling points, i.e. during the evaporation operation it evaporates in a larger quantity and at

the condensation operation is condensed

it in less quantity than is the case without it

presence of the solid body.

It is particularly advantageous to carry out both

the partial evaporation and the partial

condensation in the presence of suitable solids

bodies. For this purpose, the liquid mixture is directed over large surfaces of layers

of such a solid body, whose infrared spectral band crosses the infrared spectral spatial band of the liquid component which

must be separated, whereby the liquid mixture

evaporates partially (and then relatively

large part of the component to be separated

f i-a). The vaporized part is then directed over large surfaces of layers of another solid body whose infrared spectrum band crosses the infrared spectrum band of the other (which is not to be separated) liquid component, whereby the components to be separated are condensed to a relatively greater degree.

The transport of the liquid vapors can also be carried out using a chemically inert carrier gas.

Example 1.

A current of 10 cmVmin. water of 18° C, i.e. a mixture of approx. 7000 parts H20 [oscillation band 1550—1700 cm—i (max. 1596 cm-' + 1650 cm-i) and 3700—3800 cm-i (max. 3756 cm-')] and 1 part D20 [oscillation band 1150—1250 cm -i (max. 1180 cm-1 + 1220 cm-i) and 2500—2800

cm-i (max. 2512 cm-1 + 2784 cm~i)]

is led from a tube (A in the drawing) with a diameter of 0.3 cm through a Jena glass frit GH (E in the drawing), which has the following oscillation band: 1000—1200 cm—'

(max. 1050 cm-') with 1 cm thickness and 6.5 cm cross-section at a temperature of 20° C. At the same time, 2.1 l/min is led in from pipe B. air with 12 percent relative humidity and 20° C. The non-evaporated liquid is withdrawn at D. The vapor-air mixture exits at C.

By cooling the steam-air mixture that emerges at C, a condensate with a deuterium oxide content of 1.1% by weight is obtained.

In order to also apply the principle according to the invention during condensation, the steam-air mixture emerging at C is led from below into a vertical metal pipe G of 2 cm cross-section and 30 cm long, which is filled with Basalt grains of 0.1-1 .0 mm cross-

section (oscillation bands 950—1150 cm-' and 3000—5000 cm-') and is heated by means of a heating jacket H to 95° C. The steam-air mixture that emerges at F contains during the first 100 minutes of running time practically spoken only H20. The water that settles on the solid body that forms the pipe inlet

held, contains the total D20 of the introduced vapor mixture. Then lead at approx. 110° C a chemically inert gas through the tube G and the existing HaO-D^O mixture which is located here for-

steamed. These vapors are condensed without

for pipe G. The liquid thus obtained consists of approx. 25 weight percent. of D20.

The deuterium oxide content was determined

according to Houben-Weil, Methoden der Orga-

nichen Chemie (1955), Volume III, Part 1, page 869, at ca. 4 ^ in infrared spectrum.

Example 2.

On a coarse-pored Jena glass frit was

filled with a 1 cm thick layer of quartz sand [oscillation band 1000—1400 cm— in (max.

about. 1250 cm-i) and 2400—2800 cm-i]. Re-

nom this layer is conducted at 70° C several times in succession 200 ems/min. water and 2.1

l/min. air. then again several times in succession 50 cm^/min. water and 2.1 l/min.

air. With a total throughput, you get

quantity of 2000 cm» of water with a deuterium oxide content of 0.28 g from steam mix-

the thing. (at C) 5.1 ems condensate with a deuterium oxide content of 5% = 0.25 g.

0.25

The dividend therefore amounts to = 90 per cent of

0.28

the deuterium oxide present.

It thus appears that enrichment fac-

tors in the first step of over 350, which is thus more than a power of ten above the factors achieved so far.

Example 3.

In an apparatus, such as is described

know in example 2, a 1 cm high layer of quartz sand is placed. To this is added 30 ems of a dioxane-water mixture with the azeotropic composition of 80 per cent dioxane and 20 per cent

water at 60° C.

[Oscillation band quartz sand: 1000—

1400 and 2400—2800 cm-i; oscillation band

dioxane: 1050-1150 cm-i (max. 1120

cm-i) and 1250—1300 cm-i (max. 1260

cm-'); oscillation band water: 1550—1700

cm-i (max. 1596—1650 cm-i) and 3700—

3800 cm-i (max. 3756 cm-')].

Through this moistened quartz sand layer

nitrogen is passed at 45° C with a flow rate of 2.1 l/min. Then con-

the gas stream passed through is condensed by the liquid part that has evaporated on the solid body during the first 30 seconds

there in a first cooling device and in the following 120 sec. in another refrigerating

nothing.

The compositions of the liquid fractions obtained (starting mixture, re-

bypass, condensate from the first cooling device

ning, condensate from other cooling equipment)

was determined over the refractive index. They beg-

voted values are indicated in the following table.

Before the measurement, the samples were heated to

boiling to expel dissolved gases.

This shows the division of azotro-

whipping mixtures according to this procedure

manner. In the passage, the water is enriched approx.

7 percent calculated on the original amount of water,

while the amount of dioxane in cooling trap 1

has gained approx. 5 percent calculated on the up-

flowable dioxane proportion.

Claims (3)

1. Procedure for the separation of difficult-to-separate liquid mixtures by means of partial evaporation or partial or condensation or by means of a combination of these processes, characterized in that the evaporation and/or condensation is carried out in the presence of solid bodies with a large surface, whose infrared spectrum band crosses the infrared spectrum bands for only one of the components in the liquid mixture. 2. Method according to claim 1 for the separation of isotopic and azeotropic liquid mixtures, characterized in that the liquid mixture is passed through layers with a large surface of solid bodies whose infrared spectrum bands cross the infrared spectrum bands of the first component of the liquid mixture, as it is partially vaporized, and that the thus obtained liquid vapor is led through layers with a large surface area of another solid body, whose infrared spectrum band crosses the infrared spectrum band for the second component, as the liquid vapor is partially condensed. 3. Method according to claims 1 and 2, characterized in that the transport of liquid vapor is carried out using a chemically inert carrier gas.