Comprehensive natural gas processing

Abstract

The present invention related to a process and an apparatus for efficient and cost-effective comprehensive processing of natural gas, including the removal of moisture and the recovery of the higher hydrocarbons components (C2+). The said apparatus comprises the following major components: an integrated natural gas processor with a dehydration section and a higher hydrocarbons absorption section; a heat transport medium cooler; an absorbent cooler; a fractional distiller for separating the light oil from the heavy oil absorbent; an inhibitor regenerator; and a refrigeration unit. The present invention provides a low-cost natural gas comprehensive processorprocessing that is universally applicable to both terrestrial and off-shore natural gas exploitation. The said apparatus also provides an efficient and cost-effective natural gas dehydrator when the dehydration section is used independently without incorporating the absorption section.

Description

BACKGROUND OF INVENTION[0001]The reduction of CO2 emission is one of the greatest concerns in combating the catastrophic “global warming” trend. As a result, the world puts much emphasis on the exploitation of “clean energy” with less or non-emission for both industrial and domestic uses. Natural gas (hereafter abbreviated as “NG”), as compared with coal and petroleum, is considered the most economic “clean” fuel that is used on a large, industrial scale at present and in the near future. In addition, the discovery of huge amount of ocean-bed gas-hydrates increases the recoverable resources of NG substantially. It is expected that, in the long run, the global NG consumption may eventually exceeds all other fossil fuels.[0002]NG is a mixture of hydrocarbon gases, consisting of mainly methane (C1) and a smaller fraction of heavier gaseous hydrocarbons (i.e., ethane, C2; propane, C3; butane, C4; pentane and higher, C5+; sometimes C3+ is called “light oil” as a whole. However, the econo...

AI Technical Summary

Benefits of technology

[0006]Accordingly, it is an objective of the present invention to provide a comprehensive NG process and a processor, based on the refrigeration dehydration and absorption technologies, for efficient and cost-effective comprehensive processing of NG. The said processor could simultaneously perform the removal of moisture and the recovery of the higher hydrocarbons (C2+) in a single piece of equipment, thus substantially reducing the capital and operational costs of the NG processing plant.

[0007]Another objective of the present invention is to provide an energy-saving comprehensive NG process and a processor that, when processing high pressure NG, does not need external energy for refrigeration.

[0009]With regard to the above and other objectives, the present invention provides a comprehensive NG process and a processor to simultaneously perform refrigeration dehydration and refrigeration absorption of higher hydrocarbon gases with maximum recovery rate at minimum energy consumption. The final product is a gaseous mixture enriched in higher hydrocarbons with minimum residual methane.

Problems solved by technology

It is expected that, in the long run, the global NG consumption may eventually exceeds all other fossil fuels.

The state-of-the-art NG processing plants generally work on a cryogenic process for efficiently separating the higher hydrocarbon gases In this process, a huge volume of NG is cooled down by expansion to a very low cryogenic temperature around −150° F. Such a process is extremely energy-consuming, and the facility usually comprises many pieces of expensive equipment, notably the molecular-sieve dehydrator, the multiple-flow finned-plate heat exchanger, and the turbo expander-compressor.

High capital and operational costs are thus resulted.

As a consequence, only a limited fraction of the NG could be processed before consumed as a fuel.

Most of the valuable higher hydrocarbon contents was improperly used.

However, most of these patents only proposed some specific improvements to the same cryogenic process.

No substantial break-through in NG processing technology has ever been proposed.

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