First, sign in to blogger and at the top right corner, click on settings (gear icon),
Second, Click on user settings.
Third, Deselect Google+ profile and choose a blogger profile.
Fourth, Switch to a limited blogger profile
Fifth, Save the settings.
To ensure your posts gets published on Google +, use a scheduling tool such as Ifttt to publish blogger posts to your Google plus profile. By disconnecting your blogger profile from Google+, you will unable to use the Google+ commenting system, but you can use the Intense debate commenting system, a powerful tool that allows your readers to connect from facebook, blogger or wordpress profiles.