$0.0 $0.2 $0.4 $0.6 $0.8 $1.0 $1.2 $1.4 $1.6 $1.8 $2.0
$3.5
$3.0
$2.5
$2.0
$1.5
$1.0
$0.5
$0.0
GO hydrotreater
Hydrocracker
Diesel hydrotreater
Naphtha hydrotreater
Catalytic reformer
I somerisation unit
95% 99% 99.9% Grey H
Blue H production cost
95% 99% 99.9% Grey H production cost
production cost
and purification of this stream would not be impossible, it would be expensive via membrane separation in all but a green H2 environment with >$8/kg H2 costs. Refineries interested in H₂ recovery from the FCC are encouraged to look at membrane separation options if they plan to transi - tion to green H₂ soon. These lower-pressure ROG streams would need H2 permeate recompression after the separation due to their lower feed pressures. However, to compare the pure sep - aration costs with the hydrotreaters and hydrocracker the same analysis was still conducted. For the case of the cat - alytic reformer purified to 99.9% purity, Table 3 shows that the estimated cost to produce fresh grey H2 from the SMR plant has already been exceeded. For this reason, this case would not be considered unless the refinery was utilising blue or green produced H₂ at higher costs. Assuming there is available H2 recycle compressor capac - ity, the recompression costs of getting the H2 stream back up to feed pressure can be considered. Again, H2 recovery over the life of a membrane unit (five years) will be reviewed Figure 1 Hydrotreater and hydrocracker recovery costs vs grey H₂ production, including recompression to feed pressures
with an assumed unit uptime of 95% (to be conservative) with total H2 production. The cost of H2 separation is then compared back to the cost to produce new H2 via a grey H2 SMR process (with an estimated price per kg of $1.80) to find the breakeven point. With these bespoke processing units, all options show a positive ROI except for the 99.9% purity case from the catalytic reformer (see Table 4 ). Again, they are highly var - iable depending on the conditions of the streams and the required purities. The ROG from the catalytic reformer is well positioned for H2 recovery from existing PSA technology. However, membrane separation could prove a better option if there is flexibility in the final purity of the H₂ product. The total H₂ recovery values vs the amount spent on membrane system Capex and compression Opex is still significant in all other cases. The isomerisation (unit 95% purity case recovers more than $22M in H2 value with only a $1.7M Capex investment and $900K in compression costs over the membrane life. The catalytic reformer 95% purity case recovers more than $74M in H2 value with only Figure 2 Isomerisation unit and catalytic reformer recovery costs vs grey H₂ production, including recompression to feed pressures
Stream
Feed
Feed Permeate
Fibre type
Feed purity
Permeate Recovery
Total
Lifetime
Flow rate pressure pressure
purity
module separation
(NM 3 /hr)
(bar)
(bar)
cost
cost ($/kg)
Catalytic reformer
20,000
20
4
High throughput
60%
95.32%
91.83%
$3.1M
$0.076
95% purity
– single stage
Catalytic reformer
20,000
20
8
High purity
60%
99.16%
92.04% $36.8M
$0.890
99% purity
– single stage
Catalytic reformer
20,000
20
6
Balanced and high purity
60%
99.91%
87.15% $78.0M
$1.991
99.9% purity
– two stage
Isomerisation unit
6,000
22
6.5
High throughput – single stage
60%
95.15%
92.39%
$1.1M
$0.090
95% purity
Isomerisation unit
6,000
22
8
High purity
60%
99.42%
91.74%
$8.8M
$0.711
99% purity
– single stage
Isomerisation unit
6,000
22
4
High throughput and high purity – two stage
60%
99.90%
87.77%
$9.7M
$0.818
99.9% purity
Table 3 Isomerisation unit and catalytic reformer analysis – no compression
17
PTQ Q3 2024
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