Minimizing mixing in a pressure exchanger

A pressure exchanger comprising:

• a rotor configured to rotate to exchange pressure between a first fluid at a first pressure and a second fluid at a second pressure, wherein the rotor forms ducts that are routed from a first distal end of the rotor to a second distal end of the rotor;
• and
• inserts disposed in the ducts to provide a length to diameter ratio of about 5 to about 10;
• and
• a first end cover disposed at the first distal end of the rotor, wherein the first end cover forms a high pressure in (HPIN) port configured to provide the first fluid at the first pressure in a substantially axial direction into the ducts, and wherein the first end cover forms a low pressure out (LPOUT) port configured to receive the first fluid from the ducts at a third pressure that is lower than the first pressure;
• and
• a second end cover disposed at the second distal end of the rotor, wherein the second end cover forms a low pressure in (LPIN) port configured to provide the second fluid at the second pressure into the ducts and forms a high pressure out (HPOUT) port configured to receive the second fluid from the ducts at a fourth pressure that is higher than the second pressure, wherein one or more first end cover radial sidewalls are offset relative to one or more second end cover radial sidewalls, and wherein the one or more first end cover radial sidewalls are associated with a same duct as the one or more second end cover radial sidewalls.