Integrated process for producing light olefins

An integrated process for producing light olefins comprising:

• passing a syngas stream to a methanol synthesis reactor to provide a reactor effluent comprising methanol;
• separating the reactor effluent into a vapor stream and a liquid stream comprising methanol;
• passing the liquid stream comprising methanol to a methanol purification section comprising a first distillation column and a second distillation column to provide a methanol product stream;
• and
• passing at least a portion of the methanol product stream to an oxygenate conversion unit comprising a separation section for separating light olefins to provide an effluent comprising olefins,
• wherein heat to said first distillation column and the second distillation column is provided from a water stream taken from the separation section.

An integrated process for producing light olefins comprising:

• passing a syngas stream to a methanol synthesis reactor to provide a reactor effluent comprising methanol;
• separating the reactor effluent into a vapor stream and a liquid stream comprising methanol;
• passing the liquid stream comprising methanol to a methanol purification section comprising a first distillation column and a second distillation column to provide a methanol product stream;
• and
• wherein a first reboiling stream of the first distillation column is heated in a reboiler of the first distillation column with a product water stream taken from the separation section and a second reboiling stream of the second distillation column is heated in a reboiler of the second distillation column with a stripped water stream of the separation section.