1. Design issues of Membrane Reformer
ECN
P.O. Box 1
NL 1755 ZG Petten
The Netherlands
Design issues of Membrane Reformer
M. Sarić, Y.C.van Delft, A. de Groot
Background
The (petro) chemical industry in the Netherlands is responsible for one sixth of the total energy use. A substantial part is used to produce industrial hydrogen. This takes place in huge reformer units where methane reacts with steam to become H2 and CO. By selective removal of H2 from the reaction zone in the membrane reformer energy efficiency of the process can be considerably increased.
Membrane reformer designs
Figure 5 Design 1
Figure 1 The membrane reformer concept
Figure 6. Design 2
Objective
System and sensitivity studies for front-end of NH3 plant
Membrane reformer design
System studies
Results: Design 1
Table 1. Number of reformer tubes required for
different heat transfer coefficients
(dt=11cm,L=9m)
U [W/m2/K]
# tubes
1001
312
301
1041
4 2
7811
1 –Branan, C.R.,2002
2- Design 1
Figure 7. Dependency of Amem ,tube lenght and Δp on different parameters
Figure 2. Conventional front –end
Figure 3. Membrane front –end
Results system and sensitivity studies
Optimum: pfeed= 30 bar, ppermeate= 5.5 bar, T= 650 ºC, counter-current mode , S/C = 3.21
Energy savings in NL
is 7.5 PJ/y.
membrane area
Amem = 6000 m2
Conclusions
Mass transfer resistance is in catalyst bed and membrane.
Coupling of the mass and heat transfer area lead to:
1. 10 x higher catalyst requirement
2. Installing 4x more heat transfer area then required => overdimensioned membrane reformer
Designing of cost effective membrane reformer requires that different processes such as mass, heat transfer, reaction rate and permeance rate are well-matched in the reactor design.
Figure 4. Compressor duty (MUG) and Amem vs. ppermeate for T= 600 ºC
We gratefully acknowledge our partners for their contribution in this project and the Dutch
Ministry of Economic Affairs for the financial support within the EOS LT programme.