KR101777697B1 - Partial regenerating apparatus for selective catalytic reduction reactor - Google Patents

Abstract

The present invention relates to a catalyst regeneration apparatus for a selective catalytic reduction reaction, and more particularly to a regeneration apparatus for partially regenerating a catalyst, comprising a selective catalytic reduction reactor in which a plurality of catalyst module stages are charged and two regeneration heating apparatuses Characterized in that the first regenerative heating device is connected to the tubes in fluid communication with the reactor inlet and the intermediate zone and the second regenerative heating device is connected to the tubes in fluid communication with the reactor intermediate zone and the outlet To a catalyst partial regeneration system for selective catalytic reduction.

Description

BACKGROUND ART [0002] Partial regenerating apparatus for selective catalytic reduction reactor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst regeneration apparatus for a selective catalytic reduction reaction, and more particularly to an apparatus for partially regenerating a catalyst.

A selective catalytic reduction (SCR) system for nitrogen oxide control, which is generally emitted from systems in the fields of industrial, utility boilers, engines and furnaces, is being utilized. The SCR system is used to reduce emissions of nitrogen oxides from the exhaust of boilers, engines and furnaces. In this system, ammonia is injected into the exhaust stream of the boiler equipped with the catalyst. Ammonia converts a large amount of nitrogen oxides from exhaust gases to water and nitrogen. The catalytically active material used in the SCR system is supported on a refractory inorganic material or a metal carrier. The carrier on which the catalytically active substance is supported is referred to as a unit catalyst body for convenience. These unit catalysts are assembled in the required number and are embedded in the case to form a catalyst module, and the catalyst modules are charged into the reactor of the SCR system in various stages to remove a large amount of nitrogen oxides from the exhaust gas using the ammonia reducing agent as described above Reduce to harmless water and nitrogen.

1A schematically shows a conventional SCR system reactor and a regeneration heating apparatus. In FIG. 1, the four-stage catalyst modules are charged in series in the SCR system reactor, and the exhaust gas from the engine is converted into harmless water and nitrogen through the reactor. However, the unit catalyst of the SCR system, BiSulfate) and SOF (Soluble Organic Fraction) are accumulated and the performance is degraded. As shown in FIG. 1B, the catalyst for deactivation as described above can be regenerated by heating the entire SCR system reactor using a normal regenerating heater.

Applicants have confirmed that the catalyst module on the upstream side of the SCR system reactor is more inactive than the downstream catalyst module. It has been found through this confirmation that it is advantageous from the viewpoint of fuel efficiency improvement and process efficiency to partially regenerate the catalyst module by heating only the front end catalyst module rather than heating the entire catalyst module composed of a plurality of in-line stages.

The present invention relates to a catalyst regeneration system for selective catalytic reduction, comprising a selective catalytic reduction reactor in which a plurality of catalyst module stages are charged in series and two regeneration heating apparatuses, And the second regenerative heating device is connected to the tubes in fluid communication with the reactor intermediate zone and the outlet. The present invention includes, but is not limited to, the following features. The selective catalytic reduction reactor may be a single reactor, but may be a combination of reactors in which two or more reactors are physically connected in series. Herein, the heating device may be referred to as a heater for regeneration. A catalyst for high-density selective catalytic reduction reaction is built in between the inlet of the reactor and a middle zone, and a catalyst for low-density selective catalytic reduction reaction is installed between the middle zone and the outlet of the reactor. .

The present invention also relates to a catalyst regeneration method for selective catalytic reduction, comprising a selective catalytic reduction reactor in which a plurality of catalyst module stages are charged in series and two regeneration heating apparatuses, The second regenerative heating device being connected to the tubes in fluid communication with the reactor intermediate zone and the outlet, wherein in the catalyst regeneration system for selective catalytic reduction reaction, the first regenerative heating And driving the apparatus to regenerate the catalyst modules charged between the reactor inlet and the intermediate zone. The present invention is characterized in that the first regeneration heating device is driven to regenerate the catalyst modules loaded between the inlet and the middle zone of the reactor, followed by driving the second regeneration heating device to charge the intermediate zone of the reactor and the outlet Regenerated catalyst modules.

In the catalyst regeneration system and method for selective catalytic reduction according to the present invention, when only regenerating catalyst modules are periodically regenerated, only the modules in the reactor zones having a high degree of inactivation are partially regenerated, And the process efficiency such as shortening the regeneration time can be improved.

1 shows a schematic view of a conventional SCR system reactor and regeneration heating device and a SCR operation (a) and regeneration (b) path.
FIG. 2 is a graph showing deactivation progress between catalyst terminals by a conventional SCR system reactor and a regeneration heater.
FIG. 3 is a schematic view of the SCR system reactor and the regeneration heating apparatus according to the present invention and the SCR operation (a) and partial regeneration; (b) and
FIG. 4 illustrates the entire regeneration path of the SCR system reactor according to the present invention.

The unit catalyst body used in the SCR system is usually manufactured in a honeycomb structure. Briefly, a carrier of the type having fine parallel gas flow passages extending from the inlet or outlet face of the honeycomb structure through it is used to form a unitary catalyst body. The passage is open so that the exhaust gas flows. Wherein the substantially straight path from the inlet to the outlet is defined by the inner wall of the catalytically active material coated as a washcoat such that the exhaust gas flowing through the passageway contacts the catalytic material. The flow path of the unit catalyst body may be any suitable cross-sectional shape and size such as a trapezoid, a rectangle, a square, a sine curve, a hexagon, an ellipse, a circle, and the like. Such a structure may have from about 10 to about 900 gas inlet openings (i.e., channels) per square inch of cross-section. These unit catalyst bodies are combined and surrounded by a case to form a catalyst module.

1 shows a schematic view of a conventional SCR system reactor and regeneration heating device and a SCR operation (a) and regeneration (b) path. In detail, in FIG. 1, the four-stage catalyst modules are charged in series in the SCR system reactor, and the exhaust gas from the engine is converted into harmless water and nitrogen through the reactor. However, Therefore, ABS (Ammonium BiSulfate) and SOF (Soluble Organic Fraction) accumulate and the performance is deteriorated. Thus, as shown in FIG. 1B, the entire catalyst reactor of the SCR system was heated to about 430 ° C. by using the normal regeneration heater to regenerate the deactivated catalyst body. Means that the catalyst stages are arranged in a line in the engine exhaust gas flow direction, which is different from a reactor charged in parallel.

However, various studies have confirmed that the catalyst module on the upstream side of the SCR system reactor is more deactivated than the downstream catalyst module. 2, the performance of the first-stage catalyst module ()) is significantly lowered over time than the second-stage catalyst module (△), and the second-stage catalyst module (△) *), And the performance of the third-stage catalyst module (*) was lower than that of the fourth-stage catalyst module (+) over time. Therefore, the present inventors have found that it is advantageous from the viewpoint of fuel efficiency improvement and process efficiency to partially regenerate the catalyst module by heating only the front end catalyst module rather than heating the entire catalyst module composed of a plurality of stages.

The present invention relates to a system and method for regenerating a catalyst for selective catalytic reduction, the system comprising a selective catalytic reduction reactor charged with a plurality of catalyst module stages and a plurality of regenerative heating apparatuses. It will be appreciated that embodiments of the present invention will now be described in the context of a catalyst regeneration system having two regenerative heating devices illustratively, although three or more heating devices may be connected to the selective catalytic reduction reactor.

Referring to FIG. 3, in the catalyst regeneration system for selective catalytic reduction reaction of the present invention, the system includes a selective catalytic reduction reactor charged with a plurality of catalyst module stages and a plurality of regeneration heating apparatuses. Specifically, the reactor is divided into a plurality of sections, and each section is charged with the catalyst module end (s). One regeneration heating device is connected to one section. The heating device includes a tube connecting the inlet and the outlet of each section, and may be a conventional heating device, which can usually be heated to 400 DEG C or higher. For example, supposing a reactor consisting of two sections, a first regenerative heating device is connected to the tubes in fluid communication with the reactor inlet and the middle zone, and a second regenerative heating device is connected to the reactor intermediate zone and the outlet And is connected to the communicating tubes. The selective catalytic reduction reactor according to the present invention may be a single reactor, but may be a combination of reactors in which two or more reactors are physically connected in series. In the case of a reactor consisting of three sections, three heating devices are connected in parallel with the reactor, the first heating device being connected to the tubes communicating with the reactor inlet and flow area in the direction of fluid flow, The apparatus is connected to the third section of the reactor in the fluid flow direction and to the tubes communicating with the second section of the reactor in the fluid flow direction and the third heating apparatus is connected to the second section of the reactor and the outlet of the reactor in the fluid flow direction Lt; / RTI > Herein, the heating device may be referred to as a heater for regeneration. Also, a catalyst for high-density selective catalytic reduction reaction is built in between the inlet of the reactor and the middle zone, and a catalyst for low-density selective catalytic reduction reaction is installed between the middle zone and the outlet of the reactor. can do.

Referring again to FIG. 3, the present invention relates to a catalyst regeneration method for selective catalytic reduction reaction, comprising a selective catalytic reduction reactor charged with a plurality of catalyst module stages and two regeneration heating apparatuses, Wherein the heating device is connected to the tubes in fluid communication with the reactor inlet and the intermediate section and the second regeneration heater is connected to the tubes in fluid communication with the reactor intermediate section and the outlet, 1 regeneration heater to regenerate the catalyst modules charged between the reactor inlet and the intermediate zone. 4, the first regeneration heating device is driven to regenerate the catalyst modules loaded between the inlet and the middle zone of the reactor, and then the second regeneration heating device is driven, And regenerating the catalyst modules loaded between the zone and the outlet.

According to the present invention, the SCR catalyst can be partially regenerated by sectioning the reactor and constituting a separate heating device for each section. This partial regeneration was realized by confirming that the deactivation of each stage was different in our multi-stage catalytic reactors. That is, not all the catalysts are affected in the same way but the activity is lowered intensively from the front, so that the regeneration of the front portion is required and the regeneration is mainly performed by heat (temperature rise) Partial regeneration can improve the fuel efficiency of the whole system by increasing the heat efficiency.

Claims (4)

A catalyst regeneration system for a selective catalytic reduction reaction comprising: a selective catalytic reduction reactor in which a plurality of catalytic module stages are charged in series and two regeneration heating devices, wherein a first regeneration heating device comprises a reactor inlet and an intermediate zone And the second regenerative heating device is connected to the tubes in fluid communication with the reactor intermediate zone and the outlet and the first regenerative heating device is driven independently of the second regenerative heating device A catalyst for a high density selective catalytic reduction reaction is charged between the inlet and the middle of the reactor and a catalyst for a low density selective catalytic reduction reaction is charged between the intermediate zone and the outlet of the reactor, The second regeneration heater is stopped and only the catalyst for high-density selective catalytic reduction reaction Minute regenerated catalyst regeneration system for selective catalytic reduction reaction. delete A catalyst partial regeneration method for selective catalytic reduction reaction comprising: a selective catalytic reduction reactor in which a plurality of catalytic module stages are charged in series and two regeneration heating apparatuses, wherein a first regeneration heating apparatus comprises a reactor inlet and an intermediate zone And a second regenerative heating device is connected to the tubes in fluid communication with the reactor intermediate zone and the outlet and a catalyst for high density selective catalytic reduction reaction is charged between the reactor inlet and the middle zone, Wherein a catalyst for a low-density selective catalytic reduction reaction is charged between the intermediate zone and the outlet of the reactor, wherein in the catalyst regeneration system for selective catalytic reduction, only the first regeneration heating apparatus is driven, And regenerating only the catalyst for the selective catalytic reduction reaction Is a partial catalyst regeneration method for a selective catalytic reduction reaction. delete

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