Gas purification apparatus and process

Abstract

Apparatus useful for purifying a gas stream comprises a heat exchanger, a monolithic supported catalyst system whose downstream end is connected in fluid communication with an inlet of the heat exchanger, a shell-and-tube heat exchanger, a catalyst system comprising a catalyst supported on a monolithic unitary support having passages therethrough, the support having a length and upstream and downstream ends at opposite ends of the length, wherein the diameter of said support is from one-half to two times the diameter of the shell of the heat exchanger, and wherein the downstream end of said support is connected in fluid communication with the inlets of said tubes by a passageway whose length does not exceed the length of the support and whose diameter is at no point less than the smaller of the diameter of said support and the diameter of said shell.

Description

[0001] This application is a division of our copending application Ser. No. 09 / 930,219, filed Aug. 16, 2001.FIELD OF THE INVENTION [0002] The present invention relates to purification of industrial gases such as carbon dioxide, helium and argon, and especially to removal of hydrocarbon and / or oxygen by catalytically assisted techniques. BACKGROUND OF THE INVENTION [0003] Industrial gases are often required to meet purity specifications. In order to meet these specifications, various impurities must be removed from the gases. Catalytic combustion plays a role in the removal of many impurities. The use of a catalyst allows the combustion to proceed at temperatures lower than would otherwise be necessary, although a temperature of as high as 1000° F. may still be required. [0004] There are numerous examples of catalytic combustion applications in gas purification. It is used to remove hydrocarbon contamination from CO2. Hydrocarbons removed in this manner include ethane, benzene, metha...

AI Technical Summary

Benefits of technology

The present invention is about a device and method for purifying a gas stream. It includes a heat exchanger with tubes and a support, a catalyst system with a support, and a source of gas to be purified. The gas passes through the heat exchanger and the catalyst system, where the catalyst system removes contaminants from the gas. The technical effect of this invention is to provide a device and method for purifying gas streams that can effectively remove contaminants.

Problems solved by technology

Hydrogen is removed from helium by this technique because the two gases are difficult to separate by other means such as distillation.

Because oxygen and argon are difficult to separate by distillation, hydrogen is added to the argon stream and combusted with the oxygen over a catalyst to form water.

The process would not be economical if energy had to be expended to heat the CO2 to these temperatures.

Because of inefficiencies in gas-to-gas heat transfer, it is impossible to recover all the heat from the purified air leaving the catalyst bed into the incoming contaminated air.

If the CO2 contains enough combustible contaminants, its temperature will rise to such a degree that the incoming gas is preheated to too great a temperature.

Complete oxygen removal is not possible over this catalyst because the temperature rise due to combustion would be too great and the catalyst would be destroyed.

Because the cost of heating the inlet gas for a catalytic combustion system can be so expensive, heat integration of these systems has been reported in the literature.

While effective for heat recovery, this method is likely to add additional expense to the system.

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