Gasification to meet refinery hydrogen, electricity and steam demands: Availability vs Costs GTC Annual Conference 4-7 October 2009 Colorado Springs S. Arienti Process Director Foster Wheeler Italiana - Power Division 1
The feasibility study case IGCC plant as only source to co-produce electricity, steam and hydrogen for a refinery: 250 MW electric energy (refinery back up electricity available for emergency only) 400 t/h HP steam @ 40 barg 400 C 60,000 Nm3/h hydrogen @ 28 barg Feedstock is pet coke from the refinery Natural gas available as back up fuel for the gas turbines Slurry feed, quench type gasifiers 120 MW nominal gas turbines Location: far east hot and humid atmospheric conditions Unitary prices considered for economics: pet coke natural gas hydrogen electric energy 20 /t 0.14 /Nm3 (5 $/MM BTU) 0.17 /Nm3 0.08 /kwh HP steam 15.55 /t 2
IGCC Block flow Diagram - Base Case Configuration 3
IGCC performance data Pet coke Hydrogen to HP steam to from refinery refinery refinery Gross Power Output Aux. Loads Net power to refinery t/h Nm 3 /h t/h MWe MWe MWe 160 60,000 400 380 130 250 4
IGCC availability assessment the concepts The spare equipment is provided for all the items whose shutdown causes the IGCC shutdown or significant capacity reduction: PUMPS & COMPRESSORS Few main IGCC sections require extensive scheduled d maintenance and can have significant unplanned shut downs: in particular GASIFIERS and GAS TURBINES IGCC maintenance program is established as an appropriate combination of the maintenance programs of these major critical components: other sections are in shadow E.g.: GT maintenance program IGCC unplanned shut downs: evaluation based on statistical data of FWI in-house data base FWI data base includes real results from Italian operating IGCCs FWI was involved in 5
IGCC availability assessment the basis Gasification: availability of each train 90% provided by Licensor based on existing solid gasifiers ASU: availability 98%; becomes 99.5% by adding 12 h oxygen storage SRU: 3x50% trains to avoid impact on IGCC availability Hydrogen plant: Membranes and PSA constituted by several modules in parallel Permeate e eate compressor is spared Gas turbines and associated HRSG: 95% availability Steam turbine: 97% availability 6
IGCC availability assessment methodology states definition STATE A Gasifier 1 B Gasifier 2 C Gasifier 3 D Gasifier 4 Capacity Probability A Gasifier 1 B Gasifier 2 C Gasifier 3 D Gasifier 4 1 1 1 1 1 100.00% 00% 65.61% 61% 90.00% 00% 90.00% 00% 90.00% 00% 90.00% 00% 2 1 1 1 0 100.00% 7.29% 90.00% 90.00% 90.00% 10.00% 3 1 1 0 1 100.00% 7.29% 90.00% 90.00% 10.00% 90.00% 4 1 0 1 1 100.00% 7.29% 90.00% 10.00% 90.00% 90.00% 5 0 1 1 1 100.00% 7.29% 10.00% 90.00% 90.00% 90.00% 6 1 1 0 0 66.66% 0.81% 90.00% 90.00% 10.00% 10.00% 7 1 0 1 0 66.66% 0.81% 90.00% 10.00% 90.00% 10.00% 8 0 1 1 0 66.66% 0.81% 10.00% 90.00% 90.00% 10.00% 9 0 0 1 1 66.66% 0.81% 10.00% 10.00% 90.00% 90.00% 10 1 0 0 1 66.66% 0.81% 90.00% 10.00% 10.00% 90.00% GASIFIER A 11 0 1 0 1 66.66% 0.81% 10.00% 90.00% 10.00% 90.00% 33% 12 1 0 0 0 33.33% 0.09% 90.00% 10.00% 10.00% 10.00% 13 0 1 0 0 33.33% 0.09% 10.00% 90.00% 10.00% 10.00% 14 0 0 1 0 33.33% 0.09% 10.00% 10.00% 90.00% 10.00% 15 0 0 0 1 33.33% 0.09% 10.00% GASIFIER 10.00% B 10.00% 90.00% 16 0 0 0 0 0.00% 0.01% 10.00% 33% 10.00% 10.00% 10.00% PETCOKE HYDROGEN Example: 4 x 33% Gasifiers GASIFIER C 33% GASIFIER D 33% 7
IGCC availability assessment methodology availability calculation Example: 4 x 33% Gasifiers Capacity levels and probabilities STATE Probability (Pk) (%) Duration (hours/year) Capacity (Ck) (%) I 94.77% 8301.9 100.00% II 4.86% 425.7 66.66% 66% III 0.36% 31.5 33.33% IV 0.01% 0.9 0.00% Total 100.00% 8760.0 - Equivalent Availability: ratio between actual syngas produced during a year and the syngas which could be produced during the year if operating all time at full capacity EA = 100% - (100%-66.66%)x4.86% - (100%-33.33%)x0.36% - (100%-0%)x0.01% = 98.10% 8
The study case Availability Block Diagram of base case GASIFIER 33% PETCOKE GASIFIER 33% 5% 95% H 2 PRODUCTION 100% HYDROGEN HP STEAM GASIFIER 33% GAS TURBINE & HRSG BYPASS 50% ELECTRIC ENERGY NATURAL GAS GAS TURBINE & HRSG 50% STEAM TURBINE 100% 9
The study case - availability and costs for different gasifier and GT numbers Alternative BASE - - A B - - C D Number of Gasifiers G G G G+1 G+1 G+1 G+2 G+2 G+2 Number of Gas Turbines GT GT+1 GT+2 GT GT+1 GT+2 GT GT+1 GT+2 Syngas from gasifiers 90.00% 90.00% 90.00% 98.10% 98.10% 98.10% 99.70% 99.70% 99.70% H2 (priority) 90.67% 90.67% 90.67% 98.26% 98.26% 98.26% 99.72% 99.72% 99.72% Syngas to GT 90.05% 90.05% 90.05% 98.14% 98.14% 98.14% 99.70% 99.70% 99.70% Export Steam 95.00% 99.63% 99.98% 95.00% 99.63% 99.98% 95.00% 99.63% 99.98% Export EE 94.37% 98.97% 99.32% 94.37% 98.97% 99.32% 94.37% 98.97% 99.32% Power Island NG operation (y/h) 823 863 866 154 161 162 25 26 26 Investment cost (M ) 951 1,053 1,155 1,002 1,104 1,206 1,053 1,155 1,257 Revenues (M /y) 303 314 314 310 321 322 312 322 323 Costs (M /y) 72 77 82 69 77 79 70 75 80 delta (M /y) 231 236 232 241 244 243 242 247 243 Payback (y) 4.1 4.5 5.0 4.2 4.5 5.0 4.4 4.7 5.2 10
Hydrogen availability versus plant investment cost (GT+1 configuration) 11
Electric Energy availability versus plant investment cost (G+1 configuration) 12
Investment payback versus products availability (G+1;GT+2) (G+2;GT+1) (G+1;GT+1) (G;GT+1) GT+1) (G+1;GT+1) (G+1;GT) 13
Investment payback versus EE availability: operating cost sensitivity (G+1 configuration) 15.0 13.0 Pay Back time [years s] 11.0 9.0 7.0 5.0 3.0 94.00% 95.00% 96.00% 97.00% 98.00% 99.00% 100.00% EE Availability Natural Gas at 5.0 US$/MMBTU Natural Gas at 3.0 US$/MMBTU 14
Investment Payback versus EE availability: Electric Energy price sensitivity (G+1 configuration) 15
IGCC Block Flow Diagram - Alternative Configuration (CO Shift) Syngas split: 50% CO Shift for the syngas fed to H2 production H2 production based on PSA Note (1): Number refers to base case (no spare) Higher flexibility in H2/EE production Higher investment cost (+15%) 16
Conclusions IGCC plant is flexible in producing the three main products: Hydrogen, Electric Energy and Steam. Membrane + PSA scheme for hydrogen production is normally applied. Higher flexibility for hydrogen production is got in the alternative configuration with CO shift, but at higher investment cost (+15%). This scheme is also adequate for CCS by limited additional facilities. The study confirms that the products availability strongly depends on the number of spare main equipment (gasifiers and gas turbines). 17
Conclusions A spare gasifier is basic in order to ensure very good hydrogen availability (98.3%) and to restrain back-up fuel consumption of the gas turbines, with a favourable payback time. A spare gas turbine is useful to increase electric energy availability to about 99%, and steam availability to 99.6%, with a reasonable investment payback time. Double sparing for main equipment (gasifiers and gas turbines) implies higher investment payback time: it may be justified only in case of specific request of extremely high availability of products. The greater the difference between product and feedstock prices, the greater the incentive to add spare components. 18
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