This study discusses the heat exchange optimization of a 450 kW water heater operating with natural gas (NG) and in cofiring mode burning solid pulverized rumen and NG. The rumen material is a byproduct from cattle slaughter processes. consisting of the waste contained in the cow stomachs and intestines. In NG mode. https://danddcollectiblers.shop/product-category/manicure-tool-sets/