An emulsion and system for catalytic pyrolysis can include a mixture of 100 parts by weight heavy oil, 5 to 100 parts by weight water, and 1 to 20 parts by weight solid catalyst particulates, which can include an oxide or acid addition salt of a Group 3-16 metal on a mineral support, such as ferric chloride on bentonite. Also, a pyrolysis system can include a charge of the emulsion, a transfer line to supply the emulsion to a pyrolysis chamber, a combustion gas source to supply a combustion gas to heat the pyrolysis chamber, a control system to maintain the pyrolysis chamber at a temperature, pressure and residence time to form a pyrolyzate vapor phase, and a vapor line to receive the pyrolyzate vapor phase from the pyrolysis chamber.