Rentech Nitrogen Partners, L.P., a spin-off of clean energy firm Rentech's nitrogen fertilizer business, filed on Friday with the SEC to raise up to $250 million in an initial public offering. The Los Angeles, CA-based company, which was founded in 1965 and booked $152 million in sales for the 12 months ended March 31, 2011, plans to list on the NYSE under the symbol RNF. It is following the footsteps of CVR Partners (UAN), which went public in early April 2011 and has generated a 38% return for investors to date. Morgan Stanley and Credit Suisse are the lead underwriters on the deal. No pricing terms were disclosed.