Catalyst bed reactor for the online removal of coke from catalyst in the reforming of coke oven gas

摘要

A catalytic reactor was developed that removes byproduct coke powder from the catalyst bed in steam reforming or cracking. This 'reciprocating bed' reactor has a simple construction, with permeable plates for the catalyst retainers, an elevating device which can withstand temperatures up to 800?C, and a device actuator located outside the heated reactor. The catalyst beds are raised and lowered intermittently by the elevating device. As a result of friction between the sides of the catalyst beds and the inner wall of the reactor, the up and down movement causes velocity distribution and shear stress in the catalyst bed, and the relative positions among the catalysts are altered in each cycle. Thus, byproduct coke powder, which can fill up the space between catalysts and thereby increase the flow resistance on the working gas through the catalyst bed, is removed during the reciprocating cycle. Because this coke removal mechanism is based on shear stress between catalysts, the required bed elevation speed is less than 10 mm/s. On the other hand, conventional coke removal methods require higher speeds along with steps such as hammering the reactor wall or shaking the reactor, which can subsequently damage reactor equipment under the high reaction temperatures. In the reciprocating cycles in the currently developed method, the filling factor in the catalyst bed varied, with the filling factor increasing during the ascending stroke and decreasing during descending stroke. However, the average filling factor subsequently remains constant after the first several cycles.