Justinus A. Satrio

Influence of inorganic salts on the primary pyrolysis products of cellulose

Processing bio-oil with the help of currently existing petroleum refinery infrastructure has been considered as a promising alternative to produce sustainable fuels in the future. The feasibility of bio-oil production and upgrading processes depend upon its chemical composition which in turn depends on the biomass composition and the process conditions of the fast pyrolysis reactions. The primary goal of this paper was to investigate the effect of mineral salts including mixtures of salts in the form of switchgrass ash on the chemical speciation resulting from primary pyrolysis reactions of cellulose and to gain an insight of the underlying mechanisms. Various concentrations of inorganic salts (NaCl, KCl, MgCl(2), CaCl(2), Ca(OH)(2), Ca(NO(3))(2), CaCO(3) and CaHPO(4)) and switchgrass ash were impregnated on pure cellulose. These samples were pyrolyzed in a micro-pyrolyzer connected to a GC-MS/FID system. Effects of minerals on the formation of (a) low molecular weight species - formic acid, glycolaldehyde and acetol, (b) furan ring derivatives - 2-furaldehyde and 5-hydroxy methyl furfural and (c) anhydro sugar - levoglucosan are reported exclusively. Further, the effect of reaction temperature ranging from 350 to 600 degrees C on the pyrolysis speciation of pure and ash-doped cellulose is also reported. The pyrolysis speciation revealed the competitive nature of the primary reactions. Mineral salts and higher temperatures accelerated the reactions that led to the formation of low molecular weight species from cellulose as compared to those leading to anhydro sugars.

Influence of pyrolysis condition on switchgrass bio-oil yield and physicochemical properties.

The poor and inconsistent physicochemical properties of bio-oil are inhibiting its industrialized production. We investigated the variability in properties of switchgrass bio-oil produced at three pyrolysis temperatures (T=450, 500, and 550 degrees C) and three feedstock moisture contents (MC=5%, 10%, and 15%) in a 3x3 factorial experiment in order to exploit opportunities to improve bio-oil properties through optimization of pyrolysis parameters. Results showed that even with the single type of feedstock and pyrolysis system, the two main factors and their interaction caused large variations in bio-oil yield and most of the measured physicochemical properties. Following improvements of bio-oil properties could be individually achieved by selecting an optimal pyrolysis condition (shown in parenthesis) comparing with the worst case: increase of bio-oil yield by more than twofold (MC=10%, T=450 degrees C), increase of pH by 20.4% from 2.74 to 3.3 (MC=10%, T=550 degrees C), increase of higher heating value by 18.1% from 16.6 to 19.6 MJ/kg (MC=10%, T=450 degrees C), decrease of density by 5.9% from 1.18 to 1.11 g/cm(3) (MC=5%, T=550 degrees C), decrease of water content by 36% from 31.4 to 20.1 wt.% (MC=5%, T=450 degrees C), decrease of viscosity by 40% from 28.2 to 17 centistokes (MC=5%, T=550 degrees C), decrease of solid content by 57% from 2.86 to 1.23 wt.% (MC=15%, T=550 degrees C), and decrease of ash content by 41.9% from 0.62 to 0.36 wt.% (MC=15%, T=550 degrees C). There is no single, clear-cut optimal condition that can satisfy the criteria for a bio-oil product with all the desired properties. Trade-offs should be balanced according to the usage of the end-products.

Production of benzaldehyde: a case study in a possible industrial application of phase-transfer catalysis

The conventional method of producing benzaldehyde by direct oxidation of toluene has a major drawback: low conversion to achieve high selectivity. Phase-transfer catalysis (PTC) may be used as an alternative route for benzaldehyde production. In the present study, routes to produce benzaldehyde from benzyl chloride in the liquid phase by using PTC have been examined based on the kinetic data obtained. Using the results of this study and the available information on the conventional route, process design simulations have been carried out for all the routes. While PTC-based processes offer advantages, the study shows that the conventional route appears to be the preferred one for this relatively large-scale organic intermediate with current conversions, selectivities, and chemical costs. However, even minor improvements in one or two PTC steps can greatly enhance the prospects of the PTC route. In general, as the processes get increasingly chemistry intensive, the PTC route becomes increasingly the preferred candidate.

Development of a Catalyst/Sorbent for Methane Reforming

This project led to the further development of a combined catalyst and sorbent for improving the process technology required for converting CH{sub 4} and/or CO into H{sub 2} while simultaneously separating the CO{sub 2} byproduct all in a single step. The new material is in the form of core-in-shell pellets such that each pellet consists of a CaO core surrounded by an alumina-based shell capable of supporting a Ni catalyst. The Ni is capable of catalyzing the reactions of steam with CH{sub 4} or CO to produce H{sub 2} and CO{sub 2}, whereas the CaO is capable of absorbing the CO{sub 2} as it is produced. The absorption of CO{sub 2} eliminates the reaction inhibiting effects of CO{sub 2} and provides a means for recovering the CO{sub 2} in a useful form. The present work showed that the lifecycle performance of the sorbent can be improved either by incorporating a specific amount of MgO in the material or by calcining CaO derived from limestone at 1100 C for an extended period. It also showed how to prepare a strong shell material with a large surface area required for supporting an active Ni catalyst. The method combines graded particles of {alpha}-alumina with noncrystalline alumina having a large specific surface area together with a strength promoting additive followed by controlled calcination. Two different additives produced good results: 3 {micro}m limestone and lanthanum nitrate which were converted to their respective oxides upon calcination. The oxides partially reacted with the alumina to form aluminates which probably accounted for the strength enhancing properties of the additives. The use of lanthanum made it possible to calcine the shell material at a lower temperature, which was less detrimental to the surface area, but still capable of producing a strong shell. Core-in-shell pellets made with the improved shell materials and impregnated with a Ni catalyst were used for steam reforming CH{sub 4} at different temperatures and pressures. Under all conditions tested, the CH{sub 4} conversion was large (>80%) and nearly equal to the predicted thermodynamic equilibrium level as long as CO{sub 2} was being rapidly absorbed. Similar results were obtained with both shell material additives. Limited lifecycle tests of the pellets also produced similar results that were not affected by the choice of additive. However, during each lifecycle test the period during which CO{sub 2} was rapidly absorbed declined from cycle to cycle which directly affected the corresponding period when CH{sub 4} was reformed rapidly. Therefore, the results showed a continuing need for improving the lifecycle performance of the sorbent. Core-in-shell pellets with the improved shell materials were also utilized for conducting the water gas shift reaction in a single step. Three different catalyst formulations were tested. The best results were achieved with a Ni catalyst, which proved capable of catalyzing the reaction whether CO{sub 2} was being absorbed or not. The calcined alumina shell material by itself also proved to be a very good catalyst for the reaction as long as CO{sub 2} was being fully absorbed by the core material. However, neither the alumina nor a third formulation containing Fe{sub 2}O{sub 3} were good catalysts for the reaction when CO{sub 2} was not absorbed by the core material. Furthermore, the Fe{sub 2}O{sub 3}-containing catalyst was not as good as the other two catalysts when CO{sub 2} was being absorbed.