比福尔 is a phonetic rendering with
比 (bǐ) for 'be/bi-',
福 (fú) for '-for-', and
尔 (ěr) for the trailing '-r' — the latter is the standard final character for any English '-r' sound (compare
彼得尔 'Peter',
福尔摩斯 'Holmes'). The 72 demons of the Ars Goetia include Bifrons, often transliterated this way in occult literature.