The calculated distance (air line) between Schwalbach am Taunus and Duisburg is approximately 118 miles respectively 189 kilometers.
By car or train, the actual journey to Duisburg is certainly longer, as only the direct route (as the crow flies) between Schwalbach am Taunus and Duisburg has been calculated here.
Air line (approximately)
189 kilometers
102 nautical miles