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.
Solution:

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