ZA200503931B - Apparatus for producing carbon monoxide by a chemical reaction process - Google Patents

Description

THIS INVENTION relates to apparatus for producing carbon monoxide by a chemical reaction process. The invention extends also to a method of carrying out the chemical reaction process in conjunction with the apparatus.

It is known to produce carbon monoxide both by a combustion process and by a chemical reaction process. The combustion process results in the production of relatively low quality, i.e. impure, carbon monoxide and where higher quality carbon monoxide is required, an expensive purification process is necessary. A known chemical reaction, which employs a chemical reaction between sulphuric acid and formic acid, produces relatively high quality carbon monoxide, but its use industrially for producing large quantities of carbon monoxide, as opposed to its use in a laboratory, has proven to be extremely difficult, particularly also because of the toxic qualities of carbon monoxide.

It is thus an object of this invention to provide apparatus that permits the production of carbon monoxide industrially in a cost effective manner by using the above chemical reaction process, the sulphuric acid and the formic acid used in the process hereinafter being collectively referred to as the reaction acids.

According to a first aspect of the invention there is provided apparatus for producing carbon monoxide by a chemical reaction process that includes a reaction between reaction acids in the form of sulphuric acid and formic acid, which includes a reactor defining a chamber having a plurality of relatively shallow reaction vessels located therein, one above the other, to permit the overflow of reaction acids consecutively from operatively higher reaction vessels to operatively lower reaction vessels, and defining a collection space for collecting overflow liquid from the lowermost reaction vessel; a first feed arrangement for feeding the reaction acids separately and in a controlled manner into the reactor and onto the operatively uppermost reaction vessel; a second feed arrangement for feeding carbon monoxide produced in a controlled manner from the reactor to an accumulator; a discharge arrangement for discharging liquid collected in the collection space defined within the chamber defined by the reactor; pressure monitoring means for monitoring the gas pressure in the reactor; and control means for controlling the operation of the first feed arrangement and of the second feed arrangement in response to gas pressures in the reactor as monitored by the pressure monitoring means.

The reactor typically comprises a cylindrical tank-type structure, operatively disposed in an axially upright configuration, within which the chamber is defined.

Each reaction vessel may define a depth that increases from the outer perimeter of the vessel towards the centre of the vessel. As such, each reaction vessel may define a shallow conical configuration. The number of reaction vessels particularly is determined such that following overflow of reaction acids from the operative uppermost reaction vessel to the operative lowermost reaction vessel and from the lowermost reaction vessel, during which the chemical reaction process occurs, the chemical reaction between the reaction acids is substantially exhausted. Typically, the reactor includes four reaction vessels. Each reaction vessel may thus define an overflow arrangement that will provide for overflow from the respective reaction vessels.

The chamber defined by the reactor particularly may define an operative upper region, within which the reaction vessels are positioned, while the collection space is defined in the operative lower region of the chamber.

The reactor of the apparatus of the invention also may include an inspection arrangement including at least one window that permits inspection into the chamber for monitoring at least one of the chemical reaction between the reaction acids while contained within the reaction vessels, the feed of the reaction acids onto the operative uppermost reaction vessel and the level of overflow liquid contained within the collection space defined within the reactor.

The first feed arrangement of the apparatus may include a first feed tank for containing sulphuric acid, a second feed tank for containing formic acid and feed conduits leading from the respective feed tanks into the reactor to permit displacement of the reaction acids onto the operative uppermost reaction vessel, each feed conduit having located in line therewith liquid displacement means for displacing a reaction acid from its feed tank to the operative uppermost reaction vessel and a closure valve that must be opened to permit the displacement of the reaction acid from its feed tank. Each feed conduit also may have a control valve located in line therewith between the liquid displacement means and the reactor for controlling the flow rate of a reaction acid into the reactor during operation of its liquid displacement means. The liquid displacement means typically is a suitable liquid pump.

The second feed arrangement of the apparatus of the invention may include a feed conduit leading from the reactor to an accumulator and a gas displacement means located in line therewith, which is operable for displacing carbon monoxide from the chamber defined by the reactor to the accumulator, to be stored therein under pressure.

The gas displacement means may be any suitable gas displacement means of which the inlet side and the outlet side are connected to the reactor and the accumulator respectively.

The second feed arrangement also may include a diversion arrangement that leads from its feed conduit at a location between the gas displacement means and the accumulator, for diverting the flow of carbon monoxide produced from the feed conduit to a location where the carbon monoxide can be released to the atmosphere.

Still further according to the invention, the feed conduit of the second feed arrangement may include, in line therewith, at least one of a moisture trap, an oil trap and a container filled with potassium hydroxide flakes, through which carbon monoxide produced must pass for drying and/or purification purposes.

The discharge arrangement of the apparatus may comprise a discharge conduit connected to the reactor in the operative base region thereof to provide communication with the operative lower region of the collection space, and a control valve located in line with the discharge conduit and that can be opened for permitting the discharge of overflow liquid collected in the collection space via the discharge conduit.

The pressure monitoring means of the apparatus may include a pressure gauge that can serve to measure and monitor the gas pressure within the chamber defined by the reactor and to communicate with the control means to provide gas pressure information to the control means to permit the control of the operation of the apparatus.

The control means of the apparatus may comprise a control arrangement that can control the operation of the first feed arrangement and thereby control the feed of reaction acids into the reactor and the operation of the second feed arrangement for controlling the displacement of carbon monoxide from the reactor. The control means may be operatively linked to the pressure monitoring means to provide for the operation of the first feed arrangement and of the second feed arrangement at least partially in response to pressure sensed by the pressure monitoring means.

The control means particularly may provide for either one or both of manual and automatic control of the apparatus of the invention and, as such, insofar as automated control is provided for, the control means may include a programmed logic controller that is suitably programmed to control the operation of the apparatus.

The apparatus of the invention also may include a venting arrangement that provides communication between the chamber defined by the reactor and the atmosphere and that includes a safety valve operable to release carbon monoxide from the chamber in response to a predetermined maximum pressure being sensed within the chamber.

Still further, the apparatus may include cooling means for cooling at least one of the reaction acids prior to being fed into the reactor and thereby controlling the temperature within the reactor during the production of carbon monoxide within the reactor.

According to a second aspect of the invention there is provided a method of producing carbon monoxide by a chemical reaction process and in conjunction with the apparatus of the present invention, the method including the steps of: feeding reaction acids in the form of sulphuric acid and formic acid separately into the reaction chamber of the apparatus and onto the operative uppermost reaction vessel in a ratio of approximately two thirds sulphuric acid to one third formic acid and thereby inducing a chemical reaction process by the reaction of the formic acid with the sulphuric acid for producing carbon monoxide and, while the feed of reaction acids into the reactor continues, providing for overflow of reaction acids from the operative uppermost reaction vessel consecutively onto operative lower reaction vessels, resulting in the chemical reaction process to be substantially exhausted; and displacing carbon monoxide produced within the reactor to an accumulator while maintaining the pressure within the reactor between zero and a negative pressure in the order of 40 kPa by displacing the carbon monoxide from the reactor at a rate faster than the rate at which the carbon monoxide is produced, each time the said negative pressure is reached interrupting the displacement until the pressure within the reactor again reaches approximately zero, when displacement is continued.

It will thus be understood that pressures existing within the apparatus of the invention, except within the accumulator, will remain very low, thereby enhancing safety in relation to the operation of the apparatus, insofar as the possibility of carbon monoxide “leaking” from the apparatus is largely eliminated.

Insofar as the method of the invention can be carried out also in conjunction with alternative configuration apparatus, the invention extends also to the above method as is carried out in conjunction with such alternative configuration apparatus.

The method of the invention may provide for venting carbon monoxide from the reactor if the pressure within the reactor exceeds a predetermined maximum pressure level.

The method also may provide for venting of carbon monoxide displaced from the reactor following initiation of the process, in order to dispose of possibly contaminated carbon monoxide.

The method of the invention also may include exposing the carbon monoxide produced to a purification and/or drying process by passing the carbon monoxide through at least one of a moisture trap, an oil trap and a tank containing potassium hydroxide.

Still further, the method of the invention may include discharging final overflow liquid from the reaction vessels and as collected within the collection space defined within the reactor, from the reactor.

Still further, the method of the invention may include cooling at least one of the reaction acids prior to being fed into the reactor, to thereby maintain the reaction temperature within the reactor below approximately 20°C.

The method of the invention is described in more detail hereafter with reference to an example of apparatus for producing carbon monoxide, in accordance with the invention, which is described hereafter with reference to the accompanying diagrammatic drawing.

The drawing illustrates schematically the configuration of apparatus for producing carbon monoxide, in accordance with the invention.

Referring to the drawing, apparatus for producing carbon monoxide, in accordance with the invention, is designated generally by the reference numeral 10. The apparatus 10 includes a reactor 12 that defines an enclosed chamber 14, the chamber having four shallow, conical reaction vessels 16 located therein, one above the other, to permit the overflow of reaction acids, as hereafter described, consecutively from operatively higher reaction vessels to operatively lower reaction vessels. The reactor 12 also defines a collection space 18 in the base region thereof, where overflow liquid from the lowermost reaction vessel 16.4 can be collected.

The reactor 12 also has pressure sensing means associated with a pressure gauge 20 located thereon, permitting the pressure within the chamber 14 defined by the reactor to be continuously monitored. Still further, a safety valve 22 is connected in communication with the chamber 14, the valve having a venting pipe 24 extending therefrom. This arrangement permits venting of gases from the chamber 14 when the gas pressure within the chamber exceeds a predetermined maximum level, as hereafter described.

The reactor 12 also is associated with a discharge line 26 via a control valve 28, providing for the discharge of liquid from the collection space 18 when required and as described hereafter.

Still further, the reactor is associated with two inspection windows 30 which permit inspection into the chamber 14, for purposes described in more detail hereafter.

The apparatus 10 includes further two feed tanks 32 for containing sulphuric acid and from which sulphuric acid can be displaced into the chamber 14 defined by the reactor 12, particularly onto the operative uppermost reaction vessel 16.1. A liquid displacement pump 34 provides for the required displacement of the sulphuric acid, while a control valve 36 controls the particular flow rate of the sulphuric acid onto the reaction vessel 16.1. A further feed tank 38 is provided for containing formic acid and is also associated with a liquid displacement pump 40 and a control valve 42, to provide for the controlled feed of formic acid onto the reaction vessel 16.1. During the feed of reaction acids into the chamber 14, valves 44 and 46 will be open, while these valves will be shut when the apparatus 10 is not in use.

The apparatus 10 includes still further an accumulator 48 within which carbon monoxide produced is collected, it being particularly envisaged that carbon monoxide can be charged into the accumulator to be contained therein at a pressure of up to approximately 10 bars. The accumulator 48 is connected in gas communication with the chamber 14 via a gas feed line 50, a compressor 52 providing for the displacement of gas produced from the chamber 14 to the accumulator 48. A moisture trap 54, an oil trap 56 and a container 58 containing potassium hydroxide flakes are provided in line with the feed line 50, in order to remove impurities from carbon monoxide produced and to dry the carbon monoxide produced.

A diversion line 60 for diverting carbon monoxide produced from the feed line 50 also is provided, the diversion line 60 being connected in line with the vent pipe 24, again to permit carbon monoxide to be released to the atmosphere when required, as described hereafter. The control valves 62 particularly serve to either divert carbon monoxide produced or to permit the feed of the carbon monoxide produced to the accumulator, as is clear from the drawing.

The control over the operation of the apparatus 10 either is manual, partially manual and partially automated, or fully automated. When automated, a suitable programmed logic controller is provided that can control opening and closing of the various valves as is described hereafter, as well as operation of the pumps and the compressor, in order to control the production of carbon monoxide within the reactor, particularly also in response to pressures sensed by the pressure sensing means associated with the pressure gauge 20.

The method of producing carbon monoxide particularly is initiated by opening the valve 44 and the valve 36 and activating the pump 34, in order to provide for feed of sulphuric acid into the reaction vessel 16.1 at a controlled rate. Once the reaction vessel 16.1 is approximately two thirds filled, the valves 46 and 42 are opened and the pump 40 is activated, in order to provide for the feed of formic acid into the sulphuric acid contained within the reaction vessel 16.1 By suitable control of the valves 36 and 42, provision particularly is made for the continued feed of sulphuric acid and formic acid into the reaction vessel 16.1 in a ratio of approximately two thirds to one third.

By the feed of formic acid into the reaction vessel 16.1, a chemical reaction process is initiated that provides for the production of carbon monoxide.

When the operative uppermost reaction vessel 16.1 is fully filled with the reaction acids, overflow from this vessel into the vessel 16.2 will occur, each reaction vessel 16 being associated with a suitable weir arrangement that will provide for overflow from a higher reaction vessel into a lower reaction vessel. The chemical reaction process will continue as the reaction acids pass from one reaction vessel to the other, the chemical reaction process becoming effectively exhausted at the time when liquid overflow from the operative lowermost reaction vessel 16.4 into the collection space 18 in the base region of the reactor 12 occurs.

Carbon monoxide produced by the chemical reaction process is displaced from the chamber 14 by the operation of the compressor 52, the first carbon monoxide produced being diverted from the feed line 50 and vented to the atmosphere, insofar as this carbon monoxide may still be contaminated. After a predetermined period of time the diversion will discontinue and further carbon monoxide produced will be fed to the accumulator 48, particularly via the moisture trap 54, the oil trap 56 and the tank 58, ensuring that carbon monoxide reaching the accumulator 48 is substantially pure and dry. Insofar as this purification and drying is essentially conventional and additional or alternative filtering means also can be provided for, this is not described in further detail herein.

Referring again to the reaction process and the pressures sensed within the chamber 14, it is envisaged that the rate at which gas is displaced from the chamber 14 will be greater than the rate at which carbon monoxide is produced through the reaction process, the displacement of carbon monoxide initially continuing until a negative pressure in the order of 40 kPa is sensed within the chamber 14. At that stage the compressor is deactivated, allowing carbon monoxide to be produced by the process until the pressure within the vessel reaches approximately zero. At that time the compressor is again activated and this process is continued for as long as carbon monoxide is produced. When the pressure within the accumulator reaches approximately 10 bar, the overall process is discontinued, through suitable deactivation of the pumps and the compressor and operation of the valves as described above.

It will be understood that the discharge arrangement provided by the discharge line 26 and the control valve 28 will permit the discharge of liquid collected within the collection space 18.

Failure of the proper operation of the process as above described which results in the pressure within the chamber exceeding a predetermined limit, will result in the safety valve 22 opening in order to provide for the release of carbon monoxide to the atmosphere. Thereby, the inherent dangers associated with the toxicity of carbon monoxide is effectively dealt with, rendering the chemical reaction process in association with the use of the apparatus extremely safe. It is envisaged in this regard also that the location of the apparatus may be associated with various sensor means that will shut down the apparatus in response to the existence of carbon monoxide externally of the apparatus being sensed. Once again, it will be understood that various safety procedures and precautions can be taken in order to enhance the safe use of the apparatus 10.

In order to maintain the reactor temperature at a level at which particularly the formic acid will not evaporate and contaminate carbon monoxide produced, either one or both of the reaction acids will be cooled down prior to being fed into the reactor 12, typically to a level at which the reactor temperature will remain below 20°C. The apparatus clearly includes any suitable cooling means (not shown in detail) for this purpose.

It will be understood also that the particular process as above described can be varied in various different respects while still producing carbon monoxide in the manner described. The invention extends also to such variations, not only in relation to the method, but also in relation to the apparatus as described. It is believed that the apparatus and the method described provide an extremely cost effective means for producing carbon monoxide of a high grade food quality and that will permit use of the carbon monoxide within a food treatment process. Carbon monoxide collected within accumulators as above described can thus be used for this, or any other purpose.

Claims (1)

1. Apparatus for producing carbon monoxide by a chemical reaction process that includes a reaction between reaction acids in the form of sulphuric acid and formic acid, which includes a reactor defining a chamber having a plurality of relatively shallow reaction vessels located therein, one above the other to permit the overflow of reaction acids consecutively from operatively higher reaction vessels to operatively lower reaction vessels, and defining a collection space for collecting overflow liquid from the lowermost reaction vessel; a first feed arrangement for feeding the reaction acids separately and in a controlled manner into the reactor and onto the operative uppermost reaction vessel; a second feed arrangement for feeding carbon monoxide produced in a controlled manner from the reactor to an accumulator; a discharge arrangement for discharging liquid collected in the collection space defined within the chamber defined by the reactor; pressure monitoring means for monitoring the gas pressure in the reactor; and control means for controlling the operation of the first feed arrangement and of the second feed arrangement in response to gas pressures in the reactor as monitored by the pressure monitoring means.

14 . 9005/039%%

2. Apparatus as claimed in Claim 1, in which the reactor comprises a cylindrical tank- type structure, operatively disposed in an axially upright configuration, within which the chamber is defined.

3. Apparatus as claimed in Claim 1 or Claim 2, in which each reaction vessel defines a depth that increases from the outer perimeter of the vessel towards the centre of the vessel.

4. Apparatus as claimed in any one of Claims 1 to 3, in which each reaction vessel defines an overflow arrangement that will provide for overflow from the respective reaction vessels.

5. Apparatus as claimed in any one of the preceding claims, in which the chamber defined by the reactor defines an operative upper region, within which the reaction vessels are positioned, while the collection space is defined in the operative lower region of the chamber.

6. Apparatus as claimed in any one of the preceding claims, in which the reactor includes an inspection arrangement including at least one window that permits inspection into the chamber for monitoring at least one of the chemical reaction between the reaction acids while contained within the reaction vessels, the feed of the reaction acids onto the operative uppermost reaction vessel and the level of overflow liquid contained within the collection space defined within the reactor.

7. Apparatus as claimed in any one of the preceding claims, in which the first feed arrangement includes a first feed tank for containing sulphuric acid, a second feed tank for containing formic acid and feed conduits leading from the perspective feed tanks into the reactor to permit displacement of the reaction acids onto the operative uppermost reaction vessel, each feed conduit having located in line therewith liquid displacement means for displacing a reaction acid from its feed tank to the operative uppermost reaction vessel and a closure valve that must be opened to permit the displacement of the reaction acid from its feed tank.

8. Apparatus as claimed in Claim 7, in which the feed conduits each have a control valve located in line therewith between its liquid displacement means and the reactor for controlling the flow rate of a reaction acid into the reactor during operation of its liquid displacement means.

9. Apparatus as claimed in any one of the preceding claims, in which the second feed arrangement includes a feed conduit leading from the reactor to an accumulator and a gas displacement means located in line therewith which is operable for displacing carbon monoxide from the chamber defined by the reactor to the accumulator, to be stored therein under pressure.

10. Apparatus as claimed in Claim 9, in which the second feed arrangement includes a diversion arrangement that leads from its feed conduit at a location between the gas displacement means and the accumulator, for diverting the flow of carbon monoxide produced from the feed conduit to a location where the carbon monoxide can be released to the atmosphere.

11. Apparatus as claimed in Claim 9 or Claim 10, in which the feed conduit of the second feed arrangement includes, in line therewith, at least one of a moisture trap, an oil trap and a container filled with potassium hydroxide flakes, through which carbon monoxide produced must pass for drying and/or purification purposes.

12. Apparatus as claimed in any one of the preceding claims, in which the discharge arrangement comprises a discharge conduit connected to the reactor in the operative base region thereof to provide communication with the operative lower region of the collection space, and a control valve located in line with the discharge conduit and that can be opened for permitting the discharge of overflow liquid collected in the collection space via the discharge conduit.

13. Apparatus as claimed in any one of the preceding claims, in which the pressure monitoring means includes a pressure gauge that can serve to measure and monitor the gas pressure within the chamber defined by the reactor and to communicate with the control means to provide gas pressure information to the control means to permit its control of the operation of the apparatus.

14. Apparatus as claimed in any one of the preceding claims, in which the control means includes a control arrangement that can control the operation of the first feed arrangement and thereby control the feed of reaction acids into the reactor and the operation of the second feed arrangement for controlling the displacement of carbon monoxide from the reactor.

15. Apparatus as claimed in claimed in Claim 14, in which the control means is operatively linked to the pressure monitoring means to provide for the operation of the first feed arrangement and of the second feed arrangement at least partially in response to pressures sensed by the pressure monitoring means.

16. Apparatus as claimed in any one of the preceding claims, in which the control means includes a programmed logic controller that is suitably programmed to control the operation of the apparatus.

17. Apparatus as claimed in any one of the preceding claims, which includes a venting arrangement that provides communication between the chamber defined by the reactor and the atmosphere and that includes a safety valve operable to release carbon monoxide from the chamber in response to a predetermined maximum gas pressure being sensed within the chamber.

18. Apparatus as claimed in any one of the preceding claims, which includes cooling means for cooling at least one of the reaction acids prior to being fed into the reactor and thereby controlling the temperature within the reactor during the production of carbon monoxide within the reactor.

19. A method of producing carbon monoxide by a chemical reaction process and in conjunction with the apparatus as claimed in Claim 1, the method including the steps of: feeding reaction acids in the form of sulphuric acid and formic acid separately into the reaction chamber of the apparatus and onto the operative uppermost reaction vessel in a ratio of approximately two thirds sulphuric acid to one third formic acid and thereby inducing a chemical reaction process by the reaction of the formic acid with the sulphuric acid for producing carbon monoxide and, while the feed of reaction acids into the reactor continues, providing for overflow of reaction acids from the operative uppermost reaction vessel consecutively onto operative lower reaction vessels, resulting in the chemical reaction process to be substantially exhausted; and displacing carbon monoxide produced within the reactor to an accumulator while maintaining the pressure within the reactor between zero and a negative pressure in the order of 40 kPa by displacing the carbon monoxide from the reactor at a rate faster than the rate at which the carbon monoxide is produced, each time the said negative pressure is reached interrupting the displacement until the pressure within the reactor again reaches approximately zero, when displacement is continued.

20. A method as claimed in Claim 19, which includes venting carbon monoxide from the reactor if the pressure within the reactor exceeds a predetermined maximum pressure level.

21. A method as claimed in Claim 19 or Claim 20, which includes exposing the carbon monoxide produced to a purification and drying process by passing the carbon monoxide through at least one of a moisture trap, an oil trap and a tank containing potassium hydroxide.

22. A method as claimed in anyone of Claims 19 to 21, which includes discharging final overflow liquid from the reaction vessels and as collected within the collection space defined within the reactor, from the reactor.

23. A method as claimed in any one of Claims 19 to 22, which includes cooling at least one of the reaction acids prior to being fed into the reactor, to thereby maintain the reaction temperature within the reactor below approximately 20°C.

24. Apparatus for producing carbon monoxide by a chemical reaction process substantially as described in the specification with reference to and as illustrated in the accompanying diagram.

25. A method of producing carbon monoxide by a chemical reaction process substantially as described in the specification. DATED THIS 13™ DAY OF MAY 2005 ADAMS & ADAMS APPLICANTS PATENT ATTORNEYS