The parameter qxps.render.recycle.interval defined in ServerApp.properties in QuarkXPress Server is used to recycle all sub-renderers once after 24 hours. This helps relieve any hanged request with QuarkXPress Server.
The default value for this parameter is 24 Hours. Decimal values are permitted in this setting as well. So, you can set the time in minutes as follows:
To set the value to 30 Minutes: 30/60 = 0.5
qxps.render.recycle.interval = 0.5