Natural gas (methane) is transported through a 20 in. sch 40 commercial steel pipeline at a rate of $30,000 \mathrm{scfm}$. The gas enters the line from a compressor at $100 \mathrm{psia}$ and $70^{\circ} \mathrm{F}$. Identicalcompressor stations are located every 10 miles along the line, and at each station the gas is recompressed to $100 \mathrm{psia}$ and cooled to $70^{\circ} \mathrm{F}$.

(a) Determine the suction pressure at each compressor station.

(b) Determine the horsepower required at each station if the compressors are $80 %$ efficient.

(c) How far apart could the compressor stations be located before the flow in the pipeline becomes choked?