A system for melting contaminant-laden solids that have been separated from a hydrocarbon-containing vapor stream in a hydrocarbon distillation tower, comprising at least one plate positioned where the solids form within the hydrocarbon distillation tower, hollow tubing forming an integral part of each of the at least one plate, and a heating medium disposed to flow through the hollow tubing at a higher temperature than a temperature of the solids to at least partially melt the solids.

To provide a process for separating hydrocarbons capable of recovering ethane or propane, including improved cold heat recovery enabling a reduction in compressor power. A process for separating hydrocarbons, in which a residual gas enriched with methane or ethane and a heavy fraction enriched with a lower volatile hydrocarbon are separated, includes: a) partially condensing the feed gas by cooling using the residual gas and another refrigerant as a refrigerant, followed by vapor-liquid separation; b) depressurizing and supplying the liquid obtained from step (a) to the distillation column; c) expanding a part or all of the gas obtained from step (a) by an expander to cause partial condensation, followed by vapor-liquid separation; d) feeding the liquid obtained from step (c) to the distillation column after using it as the further refrigerant in step (a); e) feeding a part or all of the gas obtained from step (c) to the distillation column; and f) obtaining the residual gas from the top of the distillation column and the heavy fraction from the bottom of the distillation column.

The invention relates to a method for separating air by cryogenic distillation in a set of columns including a first column operating at a first pressure, a second column operating at a second pressure which is lower than the first pressure, and a third column operating at a third pressure, which is lower than the second pressure, wherein the third column includes first and second evaporator-condensers, and nitrogen from a cold compressor is sent to one of the evaporator-condensers.

Provided are an apparatus and a method for separation and recovery of propane and heavier hydrocarbons from LNG. The apparatus has, from the upstream side toward the downstream side of LNG supply, first column (3) equipped with first column overhead condenser (2), first column bottom reboiler (4) and side reboiler (5), and second column (14) equipped with second column overhead condenser (11) and second column bottom reboiler (15). The first column (3) separates methane and a part of ethane as an overhead vapor and separates remaining ethane and C3 or higher hydrocarbons as a bottom liquid. The second column (14) separates ethane as an overhead vapor and separates C3 or higher hydrocarbons as a bottom liquid.

A system for melting contaminant-laden solids that have been separated from a hydrocarbon-containing vapor stream in a hydrocarbon distillation tower, comprising at least one plate positioned where the solids form within the hydrocarbon distillation tower, hollow tubing forming an integral part of each of the at least one plate, and a heating medium disposed to flow through the hollow tubing at a higher temperature than a temperature of the solids to at least partially melt the solids.

A reboiler in fluid communication with a fractionator column in an offshore low temperature process removing carbon dioxide from natural gas has a vessel volume. A carbon steel tubing bundle is disposed within the vessel volume. Each tube in the bundle has an outer surface with a porous granular metal layer deposited thereon. The granular metal layer comprises a pore size distribution which promotes bubble nucleation during vaporization of a nearly pure liquid carbon dioxide stream.

An improved method for separating hydrocarbons for separating feed LNG into product LNG and a liquid fraction enriched in C3+ components is provided. Feed LNG is heated and partially vaporized by a heat exchanger to obtain a vapor-liquid two-phase stream; the whole or a liquid phase of the vapor-liquid two-phase stream is separated into first overhead vapor enriched in methane and first bottom liquid enriched in ethane and C3+ components at a first distillation column; the first bottom liquid is separated into second overhead vapor enriched in ethane and second bottom liquid enriched in C3+ components by the second distillation column; the second overhead vapor is cooled and wholly or partially condensed to obtain condensed liquid; one of two or more streams obtained by dividing the condensed liquid is mixed with the first overhead vapor; the mixed stream is totally condensed to obtain a liquid stream by heat exchange with feed LNG by the heat exchanger; the whole or a part of the liquid stream is discharged as product LNG; another of the divided streams is refluxed to the second distillation column; and the second bottom liquid is discharged as the liquid fraction enriched in C3+ components.

The power required to recover C.sub.3+ hydrocarbons from crude carbon dioxide comprising C.sub.1+ hydrocarbons and hydrogen sulfide may be reduced by distilling the crude carbon dioxide to produce carbon dioxide-enriched overhead vapor and C.sub.3+ hydrocarbon-enriched bottoms liquid such that the hydrogen sulfide is rejected with the overhead vapor. Power consumption reductions may be achieved by incorporating a heat pump cycle using carbon dioxide vapor as working fluid to provide at least a part of the refrigeration duty and using a side reboiler to reduce the bottom reboiler duty. Where the bottoms liquid is further processed to produce lighter and heavier hydrocarbon fractions, the process enables optimization of upgrading crude oil on the basis of API gravity, Reid Vapor pressure and/or viscosity.

In a process for separating at least one heavy impurity such as hydrogen sulfide from crude carbon dioxide comprising significant quantities of at least one light impurity such as non-condensable gases, involving at least one heat pump cycle using carbon dioxide-containing fluid from the process as the working fluid, the light impurity is removed from the crude carbon dioxide and carbon dioxide is subsequently recovered from the removed light impurity, thereby improving overall carbon dioxide recovery and efficiency in terms of energy consumption.

Helium can be recovered from nitrogen-rich natural gas at high pressure with low helium loss by cryogenic distillation of the natural gas after pre-treatment of the gas to remove incompatible impurities and then recovery of natural gas liquid (NGL) from the pre-treated gas by distillation. Overall power consumption may be reduced, particularly if the feed to the helium recovery column system is at least substantially condensed by indirect heat exchange against a first portion of nitrogen-enriched bottoms liquid at first pressure, and a second portion of nitrogen-enriched bottoms liquid at a second pressure that is different from the first pressure.