How can i limit outgoing emails in postfix server

I gave up on using postfix to solve this problem. Instead, I found a relatively clean way to solve the problem using MH, which is the mailer I have been using for over 15 years:

1. An outgoing mail that should be delayed by N hours is composed in the MH "draft folder" +delayN.

2. When I have finished composing the mail, to ensure that I leave the mail in the folder instead of sending it, I have a modified whatnow program that treats send as a synonym for quit if the message is stored in a folder whose name has the form delayNNN, where NNN is a nonempty sequence of digits.

3. My hourly cron job checks all relevant folders and ships files that are old enough (details elided):

   for path in $MAIL/delay*[0-9]
   do
     minutes=...
     for outgoing in $(find $path -mmin +$minutes -name '[0-9]*')
     do
       folder=... 
       msg=...
       send -draftfolder +$folder -draftmessage $msg
     done
   done
   

I hope you followed the instructions mentioned in the documentation: http://wiki.policyd.org/quotas

What you show in your question doesn't even look similar to the documentation.