You shouldn't remove your kitchen door: to do so means there will be no protected escape route you can use to escape in the event of a fire through the front door from any other room in the property.
If your existing kitchen door is a fire door, you can only replace it with another fire door.
You might want to consider fitting a heat detector in your kitchen: this differs from a smoke detector in that it only activates when it detects a rapid rise in temperature and isn’t triggered by steam or smoke. All of your alarms ideally should be interlinked through your property so that you can hear them wherever you are.
If your kitchen is open plan and there's an exposed staircase leading to it you will have to have a heat detector and you may need to take additional measures - your local building control team will be able to advise what's required.