why not:

• loop over the keys
• split multi-words into a list
• if that list contains more than one word:
  delete single words in that list,

Hint: you can also delete hash slices.

update

OK I see the problem, this is only partially solving your case:

use strict;
use warnings;
use Data::Dump qw/pp dd/;


my %hash = (
            'rendition' => '3',
            'automation' => '2',
            'saturation' => '3',
            'mass creation' => 2,
            'automation technology' => 2,            
            # why did you post broken code with a missing comma?
            'automation technology process' => 3
           );


delete @hash{ map { split / / } grep{/ /} keys %hash };

print pp \%hash;
[download]

{
  "automation technology" => 2,
  "automation technology process" => 3,
  "mass creation" => 2,
  "rendition" => 3,
  "saturation" => 3,
}
[download]

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