using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var test = "L'impianto {impianto} ha {n_fermate} fermate da definire";

        foreach (Match match in Regex.Matches(test, @"{(\w+)}"))

        {

            Console.WriteLine(Regex.Replace(match.Value, @"[{}]", ""));

        }

        Console.WriteLine(test);

    }

}