Abstract: A process is disclosed for treating carbon dioxide-containing gas streams, such as a natural gas, to selectively remove hydrogen sulfide. The process employs an absorption-stripping sequence in which hydrogen sulfide and carbon dioxide are removed from the feed gas. The net overhead vapor of the stripping column is compressed and dried and passed into a fractionation column. Relatively high purity hydrogen sulfide is withdrawn from the bottom of the fractionation column, and the net overhead vapor of the fractionation column is recycled back to the absorption zone.

Abstract: Apparatus for controlling the rate of flow of a powdered solid material such as flour, comprising a load cell supporting an inclined plate onto which the flour particles impinge after falling through an inclined gate valve. The output of the load cell is fed to a control circuit including a direct proportional control section and an integrated error section with a monitor circuit sensitive to excessive integrated errors. The control circuit acts on an electric motor controlling the opening of the gate valve to maintain a predetermined rate of flow.

Abstract: Mercury present in liquid effluents, for example, the effluent from a caustic-chlorine plant using a flowing mercury cathode, is removed by first converting the mercury to a metallic or soluble form and thereafter contacting the solution with tin-coated iron strips having tin-iron interfaces in contact with the solution. The invention also is applicable to the recovery of mercury from existing accumulations in water body sediment.

Abstract: Bilateral converters are disclosed which translate direct current voltages at one level to direct current voltages at another level. The same converter can also be used to translate direct current voltages at the second level back to direct current voltages at the first level. The converter is bilateral in the sense of converting direct current energy in both directions from a higher to a lower voltage level and from the lower to the higher level.A switching signal interrupts the direct current at the first voltage level and a transformer is used to step up or step down the voltage level. The output voltage is rectified to provide direct current power at the second voltage level. The same action takes place in the opposite direction in response to nothing more than a change in the loading placed on the system.