NOVELTY - A reaction product quenching wastewater is used by subjecting wastewater to solid-liquid separation, and enabling separated first purified quenching water to return to quencher after passing through a quenching water intermediate tank; and concentrating separated first catalyst-containing quenching wastewater, recycling concentrated second purified quenching water, and subjecting the concentrated second catalyst-containing quenching wastewater to densification treatment for obtaining third catalyst-containing quenching wastewater.    USE - Method for utilizing reaction product quenching wastewater during preparation of isobutylene by dehydrogenation of isobutane (claimed).    DETAILED DESCRIPTION - Utilizing reaction product quenching wastewater during preparation of isobutylene by dehydrogenation of isobutane, comprises:    (A) subjecting the reaction product quenching wastewater to solid-liquid separation, enabling the separated first purified quenching water to return to quencher after passing through a quenching water intermediate tank for recycling the water, and feeding the separated first catalyst-containing quenching wastewater to the next step;    (B) concentrating the separated first catalyst-containing quenching wastewater, recycling concentrated second purified quenching water, and subjecting the concentrated second catalyst-containing quenching wastewater to densification treatment for obtaining third catalyst-containing quenching wastewater; and    (C) with a drying manner, recovering the catalyst from the densified third catalyst-containing quenching wastewater in a solid form.    An INDEPENDENT CLAIM is included for a device for comprehensively utilizing reaction product quenching wastewater during preparation of isobutylene by dehydrogenation of isobutane.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the device for comprehensively utilizing reaction product quenching wastewater.    Cooler (20)    Water pump (31)    Clarifier (40)    Wastewater inlet (41)    Wastewater outlet (43)