Liquid level control in gas-liquid mixing operations
AssigneeUnion Carbide Industrial Gases Technology Corporation
InventorsLawrence M. Litz, Mark K. Weise, David A. Haid
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Abstract
A gas-liquid mixing vessel utilizes an axial flow, down-pumping impeller in a draft tube to create vortex development so as to draw gas from the overhead in a body of recirculating liquid. A surge tank is used to accommodate volume changes in the vessel, and a liquid level control feature, in which the gas phase pressures in the mixing vessel and the surge tank are adjusted, is used to maintain the liquid level in the mixing vessel at a desired level for proper vortex development.
Claims13
In a process for mixing a gas and a liquid in a mixing vessel having a hollow draft tube with an axial flow, down-pumping impeller means positioned therein for vortex development and the ingestion of gas from an overhead space within the mixing vessel into the body of liquid therein, said gas-liquid mixing operation resulting in liquid volume changes within the mixing vessel, the improvement comprising:
- (a) maintaining a secondary volume capacity, within or external to said body of liquid within the mixing vessel, for the accommodation of said liquid volume changes during the course of the gas-liquid mixing operation, with communication being provided between said body of liquid in the mixing vessel and said secondary volume capacity so that liquid can be passed from said body of liquid in the mixing vessel to said secondary volume capacity;
- (b) monitoring the liquid level of said body of liquid in the mixing vessel throughout the course of the gas-liquid mixing operation;
- and
- (c) modulating the pressure in the gas space of said secondary volume capacity in response to changes in the liquid level that occur with respect to said body of liquid in the mixing vessel so as to maintain the desired liquid level of the body of liquid for vortex development and gas ingestion while the total volume of liquid is changing over the course of said gas-liquid mixing operation, whereby the secondary volume capacity is effectively utilized to accommodate volume changes that occur throughout the gas-liquid mixing operation so that the desired liquid level can be maintained for proper vortex development and gas ingestion from the overhead gas space in said mixing vessel.
In an apparatus for mixing a gas and a liquid in a mixing vessel having a hollow draft tube with an axial flow, down-pumping impeller means positioned therein for vortex development and the ingestion of gas from an overhead gas space within the mixing vessel into the body of liquid therein, said gas-liquid mixing operation resulting in liquid volume changes within the mixing vessel, the improvement comprising:
- (a) a secondary volume capacity, within or external to said body of liquid within the mixing vessel, for the accommodation of said liquid volume changes during the course of the gas-liquid mixing operation;
- (b) communication means between the body of liquid in the mixing vessel and said secondary volume capacity so that liquid can be passed from said body of liquid in the mixing vessel to said secondary volume capacity;
- (c) means to monitor the liquid level in said body of liquid in the mixing vessel throughout the course of the gas-liquid mixing operation;
- and
- (d) conduit means for passing gas to or from the gas space of said secondary volume capacity in response to changes in the liquid level that occur with respect to said body of liquid in the mixing vessel so as to maintain the desired liquid level of the body of liquid for vortex development and gas ingestion while the total volume of liquid is changing over the course of said gas-liquid mixing operation, whereby the secondary volume capacity is effectively utilized to accommodate volume changes that occur throughout the gas-liquid operation so that the desired liquid level can be maintained for proper vortex development and gas ingestion from the overhead gas space in said mixing vessel.
Dependencies are inferred from the claim text.