The purge stream may be used to replace a portion of the methane burned in the reformer. Assuming that the purge gas is at 35°C and that it is fed directly to the reformer burners with 5% excess air at 300°C, how much heat would be released per 100 kmol of purge gas? Estimate the savings ($ per kmol of purge gas) if the purge stream is used in place of natural gas for fuel. (Take $3 per million Btu as the approximate cost of natural gas.)