Put all lines in a text file. Then try
/play #channel messages.txt 2000
This should send all messages to your channel with a 2 second = 2000 ms delay between lines.
If this works, then put in a timer to do this every 30 minutes:
/timer.#channelmessage 0 1800 play #channel messages.txt 2000
If that works (it will wait 30 minutes == 1800 seconds before starting) then you can do it automatically when you join the channel, put this in remotes (alt-r alt-r) at the top or in a new script file:
on me:*:JOIN:#channel:timer.#channelmessage 0 1800 play #channel messages.txt 2000
on me:*:PART:#channel:timer.#channelmessage off
