Summit Agricultural Group, Iowa businessman Bruce Rastetter’s firm, plans a $100 million expansion of its FS Bioenergia corn ethanol plant in Brazil’s Mato Grosso area. The expansion will more than double production, to 140 million gallons by early next year. With this expansion, FS Bioenergia will process over 50 million bushels of corn a year. In addition to the ethanol, the plant will make 14,000 tons of corn oil and 400,000 tons of feed. Rastetter, founder and CEO of Summit Agricultural Group, said there is high potential for corn ethanol in Brazil, a country known previously for ethanol made of sugar cane. Brazil can grow two corn crops a year. Alden-based Summit built the plant in a partnership with a Brazilian company. The plant opened last year.