US1977063A - Process of preparing dry carbon dioxide - Google Patents

Description

Oct. 16, 1 934. R. T. HOWES 1,977,063

PROCESS OF PREPARING DRY CARBON DIOXIDE Filed Nov. 18, 1950 Patented Oct. 16, 1934 warren STATES PROCESS OF PREPARING DRY CARBON DIOXIDE Raymond Thayer Howes, Long Beach, Calif assignor, by mesne assignments, to Hewhngs Mumper and Lewis Cruickshank, Los Angeles,

Calif.

Application November 18, 1930, Serial No. 496,416

4 Claims.

This invention relates to a process and apparatus for the manufacture or carbon dioxide gas and is especially applicable to its recovery in a substantially anhydrous form.

The principal object of the invention is to provide a means in the manufacture of carbon dioxide, wherein steam is a factor, for the complete separation or" steam, or water vapor, from carbon dioxide gas whereby the latter is recovered in a pure anhydrous condition.

The invention is also directed to an improvement on the co-pending applications of Norris Goodwin, Serial No. 405,048, filed November 5, 1929, and Serial No. 450,155, filed May 6, 1930.

By referring to the drawing, wherein Fig. 1 is an elevation, partly in section, and- Fig. 2 shows a manifolding arrangement, and as shown in said co-pending applications, an autoclave 10 is filled to a predetermined level with a mixture of a magnesium carbonate and silica, said mixture being formed as a slurry of the finely ground materials and water.

A steam spray pipe 11 is adapted to agitate the slurry in autoclave 10 while holding the autoclave under a pressure running as high as 500 pounds per square inch, or more, and at a corresponding temperature. Such pressure is held by a valve 12 in a gas discharge pipe 13 which is connected to the upper part of a steam condenser 14 of a well known type, having a plurality of tubes 15 for the passage of gases and a discharge head 16 suitably jacketed at 17 to permit the flow of cooling water from supply 18 to pass therearound and fiow through pipe 19 and around tubes 15. Valve 12 is adapted to be suitably connected in a well known manner with one, or more, containers 20 for dry carbon dioxide gas through a pipe 21, and a pipe 22 connects autoclave 10 with the lower part of condenser 14.

A conduit 24, controlled by valve 25, is provided for the discharge of the treated material from autoclave 10, and discharge head 16, which forms a reflux condenser section, is provided with a perforated circular plate supporting a bi-metallic thermostat 27 (or other equivalent heat responsive device) which actuates a valve 28 adapted to open and close an orifice 29 placed in an otherwise tight closing plate 30. The thermostat 27 is placed in reflux condenser 16 at a critical point therein, that is, a point where normally said condenser would have all the water condensed out of the passing gas at a given rate of flow, the passage of gas containing steam causing thermostat 27 and valve 28 to close orifice 29.

In this manner it will be seen that a control, distant from the actuating thermostat, is provided whereby the passage of steam into container 20 is prevented.

The operation is as follows:

Autoclave 10 being supplied with the slurry containing the raw material, which, may be pumped in through conduit 24, valves 12, 23a, and 25 are closed and steam at the desired temperature is admitted through pipe 11 until a desired pressure is reached and CO2 is started to be evolved. Valve 23 is thenopened and valve 121s opened sufliciently only. to -maintain the desired pressure and steam and carbon dioxide gas will commence to pass into condenser 14 The reaction in autoclave 10is according to the equation,-

MgCO3+SiO2- magnesium silicate-l-COz The exact formula for the magnesium silicate is unknown at present, but the reaction is complete from left to right to provide a magnesium silicate having valuable bleaching and other properties.

The steam and CO2 pass into condenser 14 and thence the pure CO2 passes through head 16 and pipe 21 into container 20, there being maintained a temperature differential whereby all the steam is condensed in condenser 14 and below the critical point of head 16 by the reduction of temperature provided by the cooling water, the condensed steam being continuously withdrawn through pipe 26.

The rate of flow is governed by the thermostat 27 which serves to open or close the valve 28 in proportion to the increase or decrease of temperature in head 16 at the critical point therein, to the end that in the upper part of head 16 there is nothing but anhydrous carbon dioxide gas, which passes under autogenous pressure to fill container 20.

Such filling will continue until a desired pressure has been reached in container 20 when the stream of gas may be diverted to another similar container, it being understood that a pressure difierential is maintained between container 20 and pipe 13.

The carbon dioxide gas thus obtained is in a pure state and suitable for the manufacture of dry ice and other uses.

Upon the completion of the reaction in autoclave 10, the valve 12 may be closed and the 11.

magnesium silicate thereby forced out through conduit 24 for use in various arts.

It is to be understood that there are many different ways of producing a mixture of carbon dioxide and Water vapor up to the temperature of steam for which the described apparatus can be used to good efiect, it being desirable to so arrange the condenser that sufiicient length of reflux condenser be provided to condense out all the water vapor by using low enough tempera tures in the cooling water. The position of plate 30 is approximately illustrated and preferably forms a discharge point from portion 16 which may, or may not, be subject to any artificial cooling.

I claim as my invention:

1. A process of producing dry carbon dioxide which comprises: treating a mixture or magnesium carbonate and silica under superatmospheric pressure with steam to produce a mixture of carbon dioxide and steam, passing a stream of said mixture into a zone of condensation wherein complete separation of water vapor from the carbon dioxide is normally effected, and permitting the carbon dioxide to flow from said zone while the temperature in said zone is at or below a point at which the water vapor is substantially completely separated, and preventing the flow of carbon dioxide from said zone if the temperature rises above said point.

2. A process of producing dry carbon dioxide which comprises: treating a mixture of magnesium carbonate and silica under superatmospheric pressure with steam to produce a mixture or" carbon dioxide and steam, passing a stream of said mixture 'into a zone of condensation wherein complete separation of water vapor from the carbon dioxide is normally effected, and permitting the carbon dioxide to flow from said zone while the temperature at a critical point in said zone is at or below a point at which the water vapor is substantially completely separated, and preventing the flow of carbon dioxide from said zone if the temperature rises above said point.

3. A process of producing dry carbon dioxide .which comprises: treating a mixture of magnesium carbonate and silica under super atmospheric pressure with steam to produce a mixture of carbon dioxide and steam, passing a stream of said mixture into a zone of condensation wherein complete separation of water vapor from the carbon dioxide is normally eirected under superatmospheric pressure, and permitting the carbon dioxide to flow from said zone while the temperature in said zone is at or below a point at which the water vapor is substantially completely separated, and preventing the flow of carbon dioxide from said zone if the temperature rises above said point.

4. A process of producing dry carbon dioxide which comprises: treating a mixture of magnesium carbonate and silica under superatmospheric pressure with steam to produce a mixture of carbon dioxide and steam, passing a stream of said mixture into a zone of condensation wherein complete separation of water vapor from the carbon dioxide is normally eiiected, and permitting the carbon dioxide to flow from said zone while the temperature at a critical point in said zone is at or below a point at which the water vapor is substantially completely separated, and preventing the flow of carbon dioxide from said zone ii the temperature rises above said point: such control being efifective at a place in said zone more distant from the place of origin of said mixture than said critical point.

RAYMOND THAYER HOWES.

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