Method for the Absorption of a Gas in a Liquid and an Apparatus for This

Abstract

A process for producing a solution of a gas in a liquid in which the gas is soluble, the solution having a predetermined concentration up to saturation. The gas and the liquid are brought together under controlled supply in a proportion corresponding to the predetermined concentration of the solution, and the gas and the liquid are caused to form a stream passing through a common conduit. The gas and the liquid in the stream are caused to intermix under the action of gravity, and the intermixing is repeated before the gas and the liquid have separated, so that the gas is substantially absorbed in the liquid, forming a gas-liquid solution of the predetermined concentration. The stream may be brought into turbulence for intensifying the intermixing of the gas and the liquid. An apparatus for performing the process comprises a conduit including a continuous tubular coil formed with a plurality of upwardly and downwardly directed sections. Suitably, elements generating turbulence are disposed within the tubular coil, as is also a pressure-sustaining valve which maintains a predetermined overpressure in the conduit is provided. Suitably, the tubular coil is shaped as a horizontal helix

Description

The invention will now be described in greater detail with reference to the accompanying drawing, which illustrates the principle of a preferred apparatus for performing the absorption.

Absorption of a gas in a liquid takes place through a controlled supply of gas, such as chlorine gas, to a conduit A and of liquid, such as water, to a conduit B in a conduit system. During the course of the absorption, a constant proportion between the gas flow rate and the liquid flow rate can be maintained in the system by means of a restrictor device 2 for the gas and a restrictor device 4 for the liquid. Pressures can be measured in the system by means of a number of pressure indicators (P1), and the flow rates can be measured by means of a number of flow indicators (F1) in the conduits. The streams of gas and liquid meet, whereupon dispersive admixing of the gas with the liquid takes place and the liquid is caused to proceed in the system under a certain overpressure through a continuous tubular coil 5 formed with a plurality of upwardly and downwardly extending tubular parts, which form a horizontal helix or a similarly shaped structure. As the gas and the liquid proceed through the turns of the coil 5, they are repeatedly mixed so that a favourable contact area between the gas and the liquid is constantly maintained. To intensify the intermixing, the tubular coil 5 suitably is provided with elements, not shown in the drawing, such as folds, for causing turbulence in the flowing stream and thereby making the absorption more efficient. The number of turns of the tubular coil 5 may also be varied to optimize the absorption. Moreover, the tubular coil 5 may be provided with packing bodies, which favour the absorption so that a shorter tubular coil 5 can be used. An overpressure (P4) is maintained in the apparatus by means of a pressure-sustaining valve 6 to speed up the process. The gas-liquid mixture exits the conduit system through a connector C.

For safety reasons, it may be important to prevent reverse flow in the gas conduit A and in the liquid conduit B. To that end, ordinary check valves are not adequate, and it is preferred to monitor the pressures in these conduits. The condition to satisfy is that the pressures P1>P2>P3, and if that condition is not satisfied, the valves 1 and 3 are automatically closed to prevent reverse flow. It is also possible to monitor and control the flow rates q₁ and q₂ to prevent reverse flow.

The invention provides a number of important advantages in comparison with prior art processes. These advantages may be summarised as follows.

• • The absorption is effective within a wide range of flow rates because the intermixing of gas and liquid takes place only with the aid of gravity and is repeated for each turn of the coil, as contrasted with, for example, a static mixer or similar apparatus, where adequate turbulence is obtained only within a narrow range of flow rates.
  • The absorption can be made more efficient by means of folds or packing bodies in the tubular coil, which permit increased turbulence and improved contact between the gas and the liquid.
  • The absorption can also be speeded up by placing the system under a suitable predetermined overpressure. The expensive materials which are often required in corrosive environments, such as chlorine, call for a compact material-saving unit.
  • There is no need for separate disposal of gas, because the liquid flow rate is adjusted for dissolution of the gas.
  • When chlorine is processed, the system contains less chlorine than is otherwise possible, and thus less chlorinated water has to be processed. As a result, there is less danger of leakage and, accordingly, an improved environment and an improved personal safety.
  • There is no need for a circulating quantity of liquid, that is, there is only a “single” flow path.
  • A compact construction is possible, which permits the tubular coil and, possibly, the entire system to be housed in a pressure-proof enclosure if particularly stringent demands with respect to environment and safety have to be met.
  • The apparatus is believed to be less costly than existing systems, because its components and/or parts can have small dimensions.

Claims

1.-10. (canceled)

11. A process for producing a solution of a gas in a liquid in which the gas is soluble, the solution having a predetermined concentration of the gas up to saturation, the process comprising: contacting the gas and the liquid in a proportion corresponding to the predetermined concentration of the solution and forming a stream of the gas and the liquid which passes through a common conduit whereby the gas and the liquid repeatedly intermix under the action of gravity before the gas and the liquid separate so that the gas is substantially absorbed in the liquid thereby forming the solution having the predetermined concentration.

12. The process of claim 11, wherein the stream is subjected to turbulent flow for intensifying the intermixing of the gas and the liquid.

13. The process of claim 12, wherein the intermixing is conducted a pressure above atmospheric pressure.

14. The process of claim 13, wherein the gas comprises chlorine and the liquid comprises water.

15. The process of claim 11, wherein the intermixing is conducted at a pressure above atmospheric pressure.

16. The process of claim 15, wherein the gas comprises chlorine and the liquid comprises water.

17. The process of claim 11, wherein the gas comprises chlorine and the liquid comprises water.

18. An apparatus for conducting the process of claim 1, wherein the apparatus comprises a continuous tubular coil formed with a plurality of upwardly and downwardly directed tubular parts.

19. The apparatus of claim 18, wherein elements producing turbulence are provided in the continuous tubular coil.

20. The apparatus of claim 19, wherein a pressure sustaining valve which maintains a predetermined overpressure is located in the common conduit and the common conduit is connected to the continuous tubular coil.

21. The apparatus of claim 20, wherein at least the continuous tubular coil is installed in a protective pressure-proof enclosure.

22. The apparatus of claim 21, wherein continuous tubular coil is provided with at least one of packing bodies and folds.

23. The apparatus of claim 21, wherein the continuous tubular coil is a horizontal helix.

24. The apparatus of claim 18, wherein a pressure sustaining valve which maintains a predetermined overpressure is located in the common conduit and the common conduit is connected to the continuous tubular coil.

25. The apparatus of claim 18, wherein at least the continuous tubular coil is installed in a protective pressure-proof enclosure.

26. The apparatus of claim 19, wherein continuous tubular coil is provided with at least one of packing bodies and folds.

27. The apparatus of claim 18, wherein the continuous tubular coil is a horizontal helix.