초록 ▼

A method of treating a gaseous hydrocarbon contained in waste gas by using adsorbent layers of single-tower or multi-tower configuration is characterized in that (1) double-cylinder type or multi-cylinder type adsorption apparatus, in which each adsorbent layer is indirectly cooled by cooling water,

A method of treating a gaseous hydrocarbon contained in waste gas by using adsorbent layers of single-tower or multi-tower configuration is characterized in that (1) double-cylinder type or multi-cylinder type adsorption apparatus, in which each adsorbent layer is indirectly cooled by cooling water, are employed as adsorption apparatus; (2) each adsorbent layer is a packed layer of one or more kinds of materials selected from activated carbon, synthetic zeolites and hydrophobic silica gel; (3) swing time required for switching between adsorption and desorption processes is set to 1 to 15 minutes; (4) each adsorbent layer is evacuated under vacuum while being purged by using part of clean gas evacuated from each adsorbent layer and/or air in the desorption process; and (5) the gaseous hydrocarbon is recovered from outflow purge gas. This method makes it possible to prevent abnormal temperature increase within each adsorbent layer and enhance the safety of the apparatus. It also makes it possible to decrease the residual gaseous hydrocarbon content of the waste gas released into the atmosphere down to 1 vol % or less.

대표청구항 ▼

[ What is claimed is:] [1.] A method of treating or recovering a gaseous hydrocarbon contained in waste gas employing a pair of adsorption apparatus which alternately performs adsorption and desorption processes, in which the waste gas containing the gaseous hydrocarbon is passed through one of the

[ What is claimed is:] [1.] A method of treating or recovering a gaseous hydrocarbon contained in waste gas employing a pair of adsorption apparatus which alternately performs adsorption and desorption processes, in which the waste gas containing the gaseous hydrocarbon is passed through one of the adsorption apparatus so that the gaseous hydrocarbon is adsorbed by adsorbent layers, enabling the adsorption apparatus to release the treated waste gas containing substantially no gaseous hydrocarbon, while at the same time the other adsorption apparatus is switched to the desorption process, the gaseous hydrocarbon adsorbed by the adsorbent is drawn by a vacuum pump to separate the gaseous hydrocarbon from said adsorbent layers, and the gaseous hydrocarbon is recovered from separated outflow purge gas, said method being characterized in that:(1) double-cylinder or multi-cylinder adsorption apparatus, in which each adsorbent layer is indirectly cooled by cooling water, are employed as said adsorption apparatus;(2) adsorbent layers include a first layer employing the hydrophobic silica gel placed on an upstream side and a second layer employing the activated carbon placed on a downstream side as said adsorbent layers;(3) swing time required for switching between the adsorption and desorption processes is set to 1 to 15 minutes;(4) each adsorbent layer is evacuated under vacuum while being purged by using part of clean gas evacuated from each adsorbent layer and/or air in the desorption process; and(5) the gaseous hydrocarbon is recovered from the outflow purge gas.