Please, add ‘text-center’ (without quotation marks) to the extra class name of the column settings to center align the button.
As far as we can see, the social icons are added to the description with the help of the Visual Composer element. You can delete the row with the module and remove the icons.
Yes, they can be removed with the CSS code, but it’ll remove the social share icons on the whole site.
To remove them only on the portfolio page, please, modify the code and add it to the Custom CSS field: