System and method for removing benzene in natural gas

Abstract

The invention relates to a system and a method for removing benzene in natural gas. The system comprises a storage tank for storing an absorbent, an absorbent delivery pump for providing powder to the absorbent, an absorption tower, a natural gas input pipe for inputting the natural gas containing benzene into the inside of a shell, a natural gas output pipe for outputting the natural gas without benzene, a heat exchanger for precooling the absorbent and an absorbent outputting pipe for outputting the benzene-absorbing absorbent, wherein the absorption tower includes a liquid distributor and a packing layer; the heat exchanger is respectively connected with the absorbent delivery pump and the absorbent outputting pipe so that the absorbent is cooled by utilizing the cold amount of the benzene-absorbing absorbent delivered by the absorbent outputting pipe, and the cooled absorbent is output through the cooling outputting pipe of the heat exchanger; and the cooling outputting pipe enters into the inside of the shell from the shell top of the absorption tower so as to connect the liquid distributor, so that the cooled absorbent flows from up to down inside the shell. By the system and method provided by the invention, the removal efficiency of benzene in the natural gas can be improved, and the equipment investment of the system can be reduced.

Description

technical field [0001] The invention relates to the technical field of removing benzene from natural gas, in particular to a system and method for removing benzene in natural gas. Background technique [0002] Natural gas is a multi-component mixed gas, its main component is alkanes, of which methane accounts for the vast majority, and there are a small amount of ethane, propane and butane, etc. In addition, natural gas usually contains acid gases such as hydrogen sulfide and carbon dioxide , benzene and water vapor, and trace amounts of inert gases (such as helium and argon, etc.). [0003] At present, one of the ways to utilize natural gas is to use liquefied natural gas. First, the natural gas extracted from the gas field is liquefied, and then transported to the location of the user of natural gas by ocean-going transport ship or tank truck, and then used after gasification. Before liquefying natural gas, it must be purified to remove acid gases, benzene, water vapor, e...

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Problems solved by technology

[0008] Depend on figure 1 It can be seen that in the prior art, part of the isopentane that has absorbed benzene is mixed with external fresh isopentane in the mixer 103, and then returned to the shell 1041 to continue the removal of benzene, which inevitably exists The back-mixing phenomenon of isopentane reduces the removal efficiency of isopentane to benzene in natural gas. At the same time, the absorption tower must use more theoretical plates to make the natural benzene content reach the standard. Therefore, the absorption tower Equipment investment is also large

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