Concentrating method for preparing acetylene by partially oxidizing natural gas

Abstract

The invention discloses a concentrating method for preparing acetylene by partially oxidizing natural gas. The method comprises a process for treating cracked gas with a pre-washing tower and a desorbing tower, and is characterized in that: a set of heating device is arranged between the pre-washing tower and the desorbing tower; and a gas carrying solvent discharged from the pre-washing tower is subjected to heating treatment and enters the desorbing tower. Due to adoption of the method, the temperature of the gas carrying solvent is raised before entering the desorbing tower, so that benzene and naphthalene in the gas carrying solvent are not crystalized in the desorbing tower, the problem of scaling of the desorbing tower is solved radically, the block resistance of the gas carrying solvent desorbing tower is greatly increased, pollution on the entire system is lowered, the running period of the entire concentrating device is increased, and the production load is prevented from being lowered.

Description

technical field [0001] The invention relates to a process for preparing acetylene by partial oxidation of natural gas, in particular to a method for enriching acetylene by partial oxidation of natural gas. Background technique [0002] The partial oxidation of natural gas to acetylene process is the reaction of natural gas and oxygen at high temperature to generate cracked gas. The cracked gas is selectively absorbed by solvent (N-methylpyrrolidone) and separated into three gas mixtures in the packed tower: ( h 2 , CO, etc.), crude acetylene, higher alkyne gas (HA), among which higher alkyne gas mainly contains: M-C 3 h 4 , P-C 3 h 4 、C 4 h 2 、C 4 h 4 、C 4 h 6 、C 6 h 6 、C 10 h 8 and other macromolecular hydrocarbons. Since most of the higher alkyne molecules are in C 4 Above, it is very easy to generate polymer (exist in the system in the form of solid state) under the change of pressure and temperature. Cracked gas contains aromatic hydrocarbons such as ben...

AI Technical Summary

Problems solved by technology

The heat of dissolution generated during the dissolution process is removed through a heat exchanger, and the solvent after removal of the heat of dissolution enters the lower part of the pre-washing tower to contact the cracked gas countercurrently, and finally saturates benzene, naphthalene and higher alkynes in the solvent, which Partially absorbed benzene, naphthalene and higher alkyne saturated solvent is sent to the middle of the desorption tower, passes through two layers of packing and is in countercurrent contact with the stripping gas from the bottom of the tower, acetylene and a small part of higher alkyne gas are removed from the solvent, accompanied by What affects the desorption process is that the temperature of the solvent drops, and the benzene and naphthalene in the solvent crystallize at low temperature. At the same time, under the influence of the polymerization of higher alkynes, the individual voids of random packing in the desorption tower become fouled, and the gap between the individual packing and the individual The spaces are also connected due to fouling, and a large number of random packings are connected together to form a "hardening" phenomenon. The void ratio and specific surface area of ​​the compacted packings are sharply reduced, the flow rate of the whole tower is seriously reduced, and "tower plugging" occurs. "Phenomenon, the solvent cannot reach the bottom of the tower

However, those skilled in the art generally believe that the clogging of the desorption tower is due to the polymerization of higher alkynes in the desorption tower, and the inventors have found in practice that it is mainly due to the crystallization of benzene and naphthalene in the solvent at low temperatures. Higher Alkyne Polymerization Leads to Blockage of Desorber

[0004] Therefore, the traditional method to solve the packing compaction of the desorption tower and improve its anti-blocking performance is to change the packing of the desorption tower, replace the Pall ring packing of the original tower with a new type of packing, and increase the flow rate of the desorption tower. The anti-clogging performance has been relatively improved, and this solution has increased the operating cost, and the above-mentioned problems of benzene, naphthalene crystallization and higher alkyne polymerization fouling still exist

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