A system for measuring and profiling process conditions within a reactor vessel wherein said system comprises: said reactor vessel that defines a reaction zone , wherein within said reaction zone is a catalyst bed , comprises catalyst particles, and said catalyst bed is characterized as having a height; an array of sensor-enabled RFID tags , wherein each sensor-enable RFID tag of said array is placed at a known height within said catalyst bed; a first RFID reader/transceiver antenna wirelessly linked to each said sensor-enabled RFID tag of said array and that is capable of transmitting a first interrogation signal and receiving a first RFID transponder signal that is transmitted responsive to said first interrogation signal; and a second RFID reader/transceiver antenna wirelessly linked to each said sensor-enabled RFID tag of said array and that is capable of transmitting a second interrogation signal and receiving a second RFID transponder signal that is transmitted responsive to said second interrogation signal; wherein each sensor-enabled RFID tag of said array is encoded with a unique non-variable identification code, and wherein each sensor-enabled RFID tag is capable of sensing a reaction condition within said reaction zone, receiving said first interrogation signal, said second interrogation signal, and, responsive to said first interrogation signal, transmitting said first RFID transponder signal, and, responsive to said second interrogation signal, transmitting said second RFID transponder signal; whereby conditions at specific locations and said known heights within said reaction zone may be determined and profiled. said reactor vessel that defines a reaction zone , wherein within said reaction zone is a catalyst bed , comprises catalyst particles, and said catalyst bed is characterized as having a height; an array of sensor-enabled RFID tags , wherein each sensor-enable RFID tag of said array is placed at a known height within said catalyst bed; a first RFID reader/transceiver antenna wirelessly linked to each said sensor-enabled RFID tag of said array and that is capable of transmitting a first interrogation signal and receiving a first RFID transponder signal that is transmitted responsive to said first interrogation signal; and a second RFID reader/transceiver antenna wirelessly linked to each said sensor-enabled RFID tag of said array and that is capable of transmitting a second interrogation signal and receiving a second RFID transponder signal that is transmitted responsive to said second interrogation signal; wherein each sensor-enabled RFID tag of said array is encoded with a unique non-variable identification code, and wherein each sensor-enabled RFID tag is capable of sensing a reaction condition within said reaction zone, receiving said first interrogation signal, said second interrogation signal, and, responsive to said first interrogation signal, transmitting said first RFID transponder signal, and, responsive to said second interrogation signal, transmitting said second RFID transponder signal; whereby conditions at specific locations and said known heights within said reaction zone may be determined and profiled. <EOS>