The invention provides steam thermal 
cracking simulating experiment apparatus and a technology. The apparatus comprises a 
raw material inlet device, a 
cracking furnace, a product quick cooling deviceand a product separation and 
recovery device, wherein the 
raw material inlet device, the 
cracking furnace, the product quick cooling device and the product separation and 
recovery device are connectedsequentially, the product quick cooling device comprises a direct cooling 
system and an indirect quick cooling device, an operation method of the direct cooling 
system comprises the following steps:a quick-cooling water injecting 
pipe is inserted vertically into a material outlet of a cracking furnace 
pipe, the end part of an inserted end is in the shape of a 
circular cone, water injecting holesare uniformly arranged in the bottom surface circumference of the end part of the 
circular cone shape, quick cooling water is directly sprayed into the cracking furnace 
pipe through the water injecting holes, and high-temperature 
pyrolysis gases subjected to quick cooling through the quick cooling water enter the indirect quick cooling device. The apparatus has the advantages that the novel product quick cooling device is adopted, thus quick cooling of the high-temperature 
pyrolysis gases is facilitated, pressure loss of the 
pyrolysis gases in the furnace pipe is reduced, coking near the quick-cooling water injecting holes is effectively prevented, smooth operation of the simulating apparatus is guaranteed, and at the same time 
simulation effect accuracy of the cracking furnace is improved.