| 摘要 |
PROBLEM TO BE SOLVED: To reduce an equipment cost, to improve energy efficiency, and to reduce a running cost by a method wherein since heat-exchange is effected between a pipe for heating and pressure atmosphere gas in a long substance running pipe, atmosphere pressure heating gas is fed in the pipe for heating and circulated. SOLUTION: A long substance running pipe 3 through which pressure atmosphere gas is circulated is arranged as an outer pipe and two pipes of one being a pipe 6a for heating for an outbound passage for atmosphere pressure heating gas and the other being a pipe 6b for heating a return passage are arranged as an inner pipe in a long substance running pipe 3. The outbound and return pipes 6a and 6b for heating communicate together through a communicating pipe 6c. An atmospheric pressure and heating gas circulation system 7 to feed atmosphere pressure and heating gas in the heating pipes 6a and 6b for heating for circulation has a combustion furnace 10 to burn, for example, city gas and LNG in an air fuel ratio of 1 or less. A circulation blower 11 is provided to feed combustion gas, generated in the combustion furnace 10, in the long substance running pipe 3 for circulation. |
