$re = '/(?x) (?<!\d) (\d{5} | K\d{4}) (?!\d)/';
$str = '(1) | 1 | 2018/ID11298 00000012345 PersoNR: 889899 Bridgestone BNPN
(2) | 3 | Kompo 32280EP ###Baukasten### 3789936690 ID PFK Carbon0
(3) | 2 | 20613, 20614, Mietop Antragsnummer C300Coup IVS 33221 ABF
(4) | 2 | Q21009 China lokal produzierte Derivate f/Radverbund 991222 VV
(5) | 6 | ID:61953 F-Pace Enfantillages (Machine arriere) VvSKPMG Lyon09
(6) | 2 | 2017/22222 22222 21895 Einzelkostenprob. 28932 ZürichMP KOS
(7) | K | ID:K1245 Panamera Nitsche Radlager Derivativ Bayreumion PwC
(8) | 7 | LaunchSupport QBremsen BBG BFG BBD 70142,70119 KK 70142';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php