The effect of methanol additive on n-decane cracking and coking over TiN coating

•The metal active sites of metal tube will catalyze methanol cracking and coking.•TiN coating can effectively inhibit metal-catalyzed coking during methanol cracking.•Methanol inhibits the chain transfer process of n-decane cracking, but the total heat sink doesn’t decrease.•Methanol inhibits small molecule free radicals from forming coking precursors by donating hydrogen.•When the mass fraction of methanol is 5%, the inhibition effect on coking is the best.