Systems and processes for cracking hydrocarbons to produce olefins herein includes heating a hydrocarbon feedstock or a mixture comprising steam and hydrocarbons to a first temperature to form a preheated feed, and also include heating steam to a second, higher, temperature in a turbomachine to form a superheated reaction steam. The preheated feed is then mixed with the superheated reaction steam to form a reaction mixture at a cracking temperature, thereby cracking the hydrocarbons to form olefins, producing a reaction effluent. The reaction effluent is then quenched and separated effluent to recover the olefins.

A method for producing N-vinylacetamide includes a feeding step of feeding a raw material containing N-(1-methoxyethyl)acetamide (MEA) to an evaporator, an evaporation step of evaporating, by the evaporator, the raw material, to form a vaporized raw material, a superheating step of feeding the vaporized raw material to a superheater, and superheating the vaporized raw material such that a superheating temperature of the vaporized raw material is equal to or more than a temperature higher by 5 C. than a boiling point of the N-(1-methoxyethyl)acetamide (MEA) under an inner pressure of the superheater and equal to or less than 200 C., and a thermal decomposition step of feeding the superheated vaporized raw material to a thermal decomposition reactor, to thermally decompose the superheated vaporized raw material, and a content of the N-(1-methoxyethyl)acetamide in the raw material is from 80 to 100 mass %.