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Design Group. Vincent Piepiora Suzanne Rapp Pablo Celestino. Synthesis to covert syngas to EtOH and HA. Synthesis to convert syngas to EtOH and HA. Main Processes: Intermediary process: Catalysts for: Direct Synthesis Methanol synthesis Direct synthesis F-T synthesis F-T synthesis
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Design Group Vincent Piepiora Suzanne Rapp Pablo Celestino
Synthesis to convert syngas to EtOH and HA Main Processes:Intermediary process:Catalysts for: Direct Synthesis Methanol synthesis Direct synthesis F-T synthesis F-T synthesis Methanol Homologation Methanol homologation ENSOL process ENSOL process Focus on: MoS2-based catalyst F-T synthesis/Direct synthesis
Homogenous More selective to EtOH Expensive Separation and recirculation is difficult Heterogeneous Suitaible for continuos process Low yield and selectivity to EtOH Catalysts
Noble metals-based Primarily supported by Rh catalyst Expensive and limited amount Non-noble metals-based Used in MeOH synthesis, F-T synthesis and Direct synthesis Produce mixture of C1-C6 alcohols High selectivity toward MeOH and isobutOH Little selectivity toward EtOH Heterogeneous
Alkali promoters • They play a significant role in activity, selectivity toward HA and lifetime of the catalysts. • Addition of alkali promoters increase the higher alcohol production in the order of Li<Na<K<Cs>Rb • Helps to suppress the formation of HC • Catlayst doping with a small amount of alkali usually increases the reaction rate. • F-T synthesis catalyst and MoS2-based catalyst - optimum alkali loading of 10 wt% and 20 wt% respectively to achieve a max selectivity for EtOH and HA.
MoS2-based catalyst- Pos. compared to other cat. • Sulphur resistant • Less severe coke deposition - even with a syngas having a low H2/CO ratio • Favours the formation of linear alcohols with a high selectivity to EtOH • Less sensitive to CO2 in the syngas stream compared to other alcohol synthesis catalysts • Requires a sulphur content (H2S) of 50-100ppm
MoS2-based catalyst • Without alkali-doping: primarily CH4 in product. • With alkali-doping: the selectivity will be shifted toward alcohols. • Ni promoted MoS2-based catalyst decreases the MeOH selectivity and increases the selectivity toward C2+ higher alcohols, especially EtOH. - HC formation, due to Ni addition, could be suppressed by modifying the catalyst with La.
Catalyst K2CO3NiMoS2 MoS2 (Dow Chemical Company) Temperature [oC] 320 or 280 295 Pressure [psig] 1160 1050 Space velocity [1/h] 2500 1300 H2/CO 1 1 Carbon selectivity to EtOH [%] 15.4 or 27.2 40.7 Carbon selectivity to MeOH [%] 6.2 or 10.8 22.7 MoS2-based catalyst
Catalyst Nanosized MoS2 patented by PowerEnterCat., Inc. Temperature [oC] 200-300 Pressure [psig] 500-3000 Space time [mg/(g cat h)] 400 Requirements Small amount of sulfur in the syngas stream or directly added to the reactor vessel Pilot plant planned[gal/d] 500 Ecalene HAS process
Direct synthesis of syngas to EtOH and HA • 2CO(g) + 4H2(g) => CH3CH2OH(g) + H2O(g) • Water-gas shift reaction: CO(g) + H2O(g) => CO2(g) + H2(g) • Side reactions, formation of: - CH4 - C2-C5 alkanes and olefins - ketones, aldehydes, esters and acetic acid • Methanation reaction: CO(g) + 3H2(g) => CH4(g) + H2O(g)