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[procengsas]

Gooday,

I am currently designing the piping network around a high temperature reactor. The reactor operates at 450 deg.C, at 1.42bara and uses hydrogen (370kg/hr) as a feed gas to this fluidised bed.The reactor is 10 inches in diameter.
Upon sizing the outlet pipe, I realised that the specific volume of hydrogen for this temperature is huge and the pipe size for a suitable pressure drop (<0.5psi/100ft) and velocity is in the region of an 8inch pipe.

Does this seem practical to size a 10inch reactor with a 8inch outlet pipe. If I go to a 6"outlet pipe my velocity of gas is 105m/s ( a bit too high with pressure drop <0.5psi/100ft). Is there any experienced people out there who can guide me as i seem to be lost. Additionally, this system needs to be designed for a low pressure drop as i need the gas to flow through coolers and then to the compressor suction.

Any assistance will be greatly appreciated.

Thanking you in advance.

[kkala]

I am currently designing the piping network around a high temperature reactor. The reactor operates at 450 deg.C, at 1.42bara and uses hydrogen (370kg/hr) as a feed gas to this fluidised bed.The reactor is 10 inches in diameter.
Upon sizing the outlet pipe, I realised that the specific volume of hydrogen for this temperature is huge and the pipe size for a suitable pressure drop (<0.5psi/100ft) and velocity is in the region of an 8inch pipe.
Does this seem practical to size a 10inch reactor with a 8inch outlet pipe. If I go to a 6"outlet pipe my velocity of gas is 105m/s ( a bit too high with pressure drop <0.5psi/100ft). Is there any experienced people out there who can guide me as i seem to be lost. Additionally, this system needs to be designed for a low pressure drop as i need the gas to flow through coolers and then to the compressor suction. Any assistance will be greatly appreciated.

There are long tubular reactors connected to the same diameter inlet / outlet piping; 10" reactor connected to 8" does not look incompatible. Check calculations or give more information on reactor (and reaction), so that somebody familiar with it could give a specific opinion.
Situation may be caused by: low operating pressure (1.42 bara) in the reactor; high reactor length/diameter ratio in order to approach plug flow conditions (minimize radial dispersion). Are these parameters usual as adopted? ΔP(max)=0.5 psi /100 ft seems in the ball park for hydrocarbon gas lines of mentioned pressure, so the reactor may be the issue. If not, downstream pipe size would be left 8" according to first para above.
Not being experienced in the field, this is only an opinion.

Edited by kkala, 16 May 2010 - 10:55 AM.