A method of operating, during an at least partial shutdown of a refrigerant distribution subsystem in a natural gas liquefaction facility, can include: draining down at least a portion of a mixed refrigerant in one or more components of the refrigerant distribution subsystem into a high-pressure holding tank of a drain down subsystem, wherein draining down to the high-pressure holding tank is achieved by pumping the mixed refrigerant from the refrigerant distribution subsystem to the high-pressure holding tank or backfilling the refrigerant distribution subsystem with a backfill gas; and optionally, transferring at least a portion of the mixed refrigerant into a low-pressure drum from the high-pressure holding tank.

An instrument air system and method is disclosed herein. The instrument air system includes a shaft-driven air compressor configured to generate instrument air by compressing atmospheric air, a power take off configured to derive drive torque from a driven rotary shaft of the process, wherein the power take off may include a concentrically-mounted clamping collar adapted to frictionally engage the driven rotary shaft, a torque-transfer assembly configured to transfer the drive torque derived by the power take off to the shaft-driven air compressor, wherein the torque-transfer assembly comprises a set of interoperating gears including a ring gear operably coupled to the clamping collar, and an instrument-air pathway configured to supply the instrument air generated by the shaft-driven air compressor to the pneumatic process-control subsystem. The instrument air system and method is useful for reducing hydrocarbon emissions of a process using a pneumatic process-control subsystem.

A process for producing one or more olefins is proposed in which a reaction input containing one or more paraffins is formed and in which a portion of the paraffin(s) present in the reaction input is converted by oxidative dehydrogenation into the olefin(s) to obtain a process gas, wherein the process gas contains at least the olefin(s), the unconverted paraffin(s), oxygen and carbon monoxide and wherein at least a portion of the process gas is subjected to a low temperature separation in which at an operating pressure level one or more gas fractions enriched in oxygen and carbon monoxide compared to the process gas are formed. It is provided that in the low temperature separation in the formation and/or for the conduction of the or at least one of the gas fractions one or more containers and/or one or more conduits having a burst pressure of at least ten times the operating pressure level are used and that the container or at least one of the containers via the or at least one of the conduits is connected to one or more heat exchangers, wherein a total length of the or of the at least one conduit between the or the at least one container and the heat exchanger(s) is not more than fifty times the internal diameter of said conduit. A corresponding plant (100) likewise forms part of the subject matter of the invention.

An equipment safety management device for managing safety of equipment capable of holding fluid is provided. The equipment safety management device includes: a safety means configured to be in fluid communication with an outlet of the equipment, the safety means being brought into a released state when pressure of the equipment reaches a previously set pressure, the safety means delivering the fluid to a flare pipe, which is fluidly communicated; and, as the flare pipe, at least one first flare pipe allowing a low-temperature fluid to flow therethrough and at least one second flare pipe allowing an aqueous fluid to flow therethrough. The safety means can deliver the fluid to both the first flare pipe and the second flare pipe.

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment not specified for such temperatures by opening and closing valves and stopping pumps. At least one interlock affects streams heated in the cold box. At least one interlock affects the streams cooled in the cold box. The interlocks are activated due to temperature determinations of process lines by temperature sensors and automatically send a signal to predetermined controllers depending on the process line with the low temperature in order to prevent exposure of equipment to low temperatures while preventing the shutdown of the cold box.

An optimized arrangement of a modularized liquefied natural gas production unit is disclosed. The arrangement comprises a cold box integral with the refrigerant fluid closed thermodynamic refrigeration cycle module.

In a process for the cryogenic separation of a methane-rich feed stream containing between 3 and 35% of oxygen and also nitrogen, the feed stream is cooled in order to produce a cooled stream, at least one portion of the cooled stream is sent to a distillation column, a bottom stream is withdrawn from the distillation column, the bottom stream being enriched in methane compared to the feed stream, a stream enriched in oxygen compared to the feed stream is withdrawn from the distillation column, and a nitrogen-rich stream is sent to the column.

The invention relates to a control system which comprises: a plurality of flow valves on channels of reaction fluid, which are i) in a closed position or ii) in an open position; a plurality of control pipes connected to a source of control fluid and to a respective control pipe, all or part of the flow valves switching to the closed position when the pressure of the control fluid in the control pipe drops below a predetermined threshold; a discharge pipe connected to the control pipes, in order to discharge the control fluid from the control pipes; a safety device connected i) to each control pipe and ii) to the discharge pipe and configured to have, selectively: i) a service configuration, wherein the control fluid flows to each control pipe, thus opening each flow valve, and ii) a safety configuration, wherein the control fluid is discharged through the discharge pipe, thus closing each flow valve.

An instrument air system and method is disclosed herein. The instrument air system includes a shaft-driven air compressor configured to generate instrument air by compressing atmospheric air, a power take off configured to derive drive torque from a driven rotary shaft of the process, wherein the power take off may include a concentrically-mounted clamping collar adapted to frictionally engage the driven rotary shaft, a torque-transfer assembly configured to transfer the drive torque derived by the power take off to the shaft-driven air compressor, wherein the torque-transfer assembly comprises a set of interoperating gears including a ring gear operably coupled to the clamping collar, and an instrument-air pathway configured to supply the instrument air generated by the shaft-driven air compressor to the pneumatic process-control subsystem. The instrument air system and method is useful for reducing hydrocarbon emissions of a process using a pneumatic process-control subsystem.

In a method for cooling a flow containing at least 35% carbon dioxide and at least 0.2 ?g/Nm.sup.3 of mercury, the mercury being in liquid and/or gas form, the flow is cooled in a first brazed aluminum plate-fin heat exchanger from a first temperature to a second temperature higher than ?38.6? C. to form a cold flow at the second temperature, and the flow cooled to the second temperature is cooled in a second heat exchanger, which is a tube and shell heat exchanger, to a third temperature lower than ?38.6? C.