... could be the pressure of steam, electricity, coal, oil, natural gas, LPG and other combustible materials.6. Control requirements: the way to ... steam, or steam + electricity, or any kinds of fuel (diesel, natural gas, liquefied petroleum gas or coal, etc.), or solid fuel ... steam, or steam + electricity, or any kinds of fuel (diesel, natural gas, liquefied petroleum gas or coal, etc.), or solid fuel ...