One or more specific embodiments disclosed herein includes a method for separating hydrogen from an olefin hydrocarbon rich compressed effluent vapor stream, employing a integrated heat exchanger, multiple gas-liquid separators, external refrigeration systems, and a rectifier attached to a liquid product drum.

A method to recover hydrocarbonfractions from refineries gas streams involves a pre-cooled heat refinery fuel gas stream mixed with a pre-cooled and expanded supply of natural gas stream in an inline mixer to condense and recover at least C.sub.3.sup.+ fractions upstream of a fractionator. The temperature of the gas stream entering the fractionator may be monitored downstream of the in-line mixer. The pre-cooled stream of high pressure natural gas is sufficiently cooled by flowing through a gas expander that, when mixed with the pre-cooled refinery fuel gas, the resulting temperature causes condensation of heavier hydrocarbon fractions before entering the fractionator. A further cooled, pressure expanded natural gas reflux stream is temperature controlled to maintain fractionator overhead temperature. The fractionator bottoms temperature may be controlled by a circulating reboiler stream.

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment or piping not specified for such temperatures by opening and closing valves and starting 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 by temperatures of process lines to prevent exposure of equipment and piping to low temperatures while preventing the shutdown of the cold box. An override controller including a predictive failure capability is also provided.

A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C.sub.2 (or C.sub.3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. A portion of the outlet vapor from the processing assembly is compressed to higher pressure, cooled and substantially condensed in a heat exchange means inside the processing assembly, then expanded to lower pressure and supplied to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.

This process comprises quenching and washing with water a gas stream derived from pyrolysis, and separating an aqueous phase from a washed gas stream; compressing, then cooling a washed gas stream; washing the compressed gas stream under pressure; passing the washed gas stream through at least one acid removal unit; drying the acid-depleted gas stream; passing the dry gas stream through at least one impurity removal unit; and feeding the purified gas stream into a cryogenic absorption unit and supplying the cryogenic absorption unit with a hydrocarbon cryogenic solvent to obtain a light gas residue, and a fraction of C.sub.2.sup.+ hydrocarbons.

A method to recover olefins and C.sub.2.sup.+ fractions from refineries gas streams. The traditional recovery methods employed at refineries are absorption with solvents and cryogenic technology using compression and expansion aided by external refrigeration systems. In contrast to known methods, there is provided first a pre-cooling heat exchanger on a feed line feeding the gas stream to a in-line mixer, secondly by injecting and mixing a stream of LNG to condense the C.sub.2.sup.+ fractions upstream of the fractionator. The temperature of the gas stream entering the fractionator is monitored downstream of the in-line mixer. A LNG stream is temperature controlled to flow through the injection inlet and mix with the feed gas at a temperature which results in the condensation of the C.sub.2.sup.+ fractions before entering the fractionator. A LNG reflux stream is temperature controlled to maintain fractionator overhead temperature. The fractionator bottoms temperature is controlled by a circulating reboiler stream.

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment or piping not specified for such temperatures by opening and closing valves and starting 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 by temperatures of process lines to prevent exposure of equipment and piping to low temperatures while preventing the shutdown of the cold box. An override controller including a predictive failure capability is also provided.

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment or piping not specified for such temperatures by opening and closing valves and starting 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 by temperatures of process lines to prevent exposure of equipment and piping to low temperatures while preventing the shutdown of the cold box. An override controller including a predictive failure capability is also provided.

A liquefaction system is capable of sequentially or simultaneously liquefying multiple feed streams of hydrocarbons having different normal bubble points with minimal flash. The liquefying heat exchanger has separate circuits for handling multiple feed streams. The feed stream with the lowest normal boiling point is sub-cooled sufficiently to suppress most of the flash. Feed streams with relatively high normal boiling points are cooled to substantially the same temperature, then blended with bypass streams to maintain each product near its normal bubble point. The system can also liquefy one stream at a time by using a dedicated circuit or by allocating the same feed to multiple circuits.

A system for processing liquified natural gas can include: a natural gas feed; a cold box; one or more natural gas cooling components; and a storage tank configured to store a refrigerant, wherein the one or more natural gas cooling components and the storage tank are located within the cold box. The cold box can be a methane cold box and the refrigerant can be propane, ethane, or ethylene. The system can also include a propane refrigerant cycle and/or an ethylene refrigerant cycle. Refrigerant stored in the methane cold box can be used to replenish refrigerant lost in the propane/ethylene cycles. The cold box can be an ethylene cold box of the ethylene refrigerant cycle. Propane can be stored in the ethylene cold box. A second storage tank can be located within a methane cold box and store ethane or ethylene.