By Marianna Parraga HOUSTON (Reuters) – U.S. producers of liquefied natural gas (LNG) boosted exports to Europe in September even as a plant outage kept overall shipments below the average for the first eight months of 2022, Refinitiv Eikon data showed on Monday. A June fire at the United States’ second-largest exporter Freeport LNG has the country’s output below its full processing capacity even as demand and prices for the superchilled gas soar on European buyers seeking alternatives to Russian gas. A total of 87 cargoes departed from U.S. ports last month carrying 6.3 million tonnes (mt) of…