Autothermal Catalytic Partial Oxidation of Bio-Oil Functional Groups: Esters and Acids

Abstract

The catalytic conversion of esters and carboxylic acids into synthesis gas or chemicals could permit optimal utilization of organic intermediates such as pyrolysis bio-oils. To examine the ester moiety, two esters, ethyl lactate and ethyl propionate, and two acids, lactic acid and propionic acid, were reformed by catalytic partial oxidation. Autothermal reforming was examined over platinum and rhodium based catalysts supported on alumina foam monoliths at a contact time on the order of 10 ms. Conversions >98% were observed for all four fuels. The addition of cerium or lanthanum was found to increase the selectivity to synthesis gas. At higher fuel to oxygen ratios, nonequilibrium species such as ethylene and acetaldehyde were observed. Ethyl propionate produced twice as much ethylene as ethyl lactate but very little acetaldehyde. The additional hydroxyl group in ethyl lactate produced acetaldehyde such that the ratio of ethylene to acetaldehyde was ∼1:1. The results provide evidence that the homogeneous decomposition of esters to intermediate acids can contribute to the overall reforming process. Products are highly tunable between synthesis gas and olefins by varying the fuel-to-oxygen ratio and the catalyst.

Autothermal Catalytic Partial Oxidation of Glycerol to Syngas and to Non‐Equilibrium Products

“…acids, [13] and even solid cellulose. [14] CPOx can be broadly broken into two regimes of interest: equilibrium conversion and the production of non-equilibrium products.…”

“…[13,19] Steep temperature gradients, as those measured in profile measurements of methane CPOx, [16] allow for non-equilibrium products to be produced and quenched before they can further decompose.…”

“…[13] It is believed that these non-equilibrium products are produced in the gas phase, in the void space of the catalyst, driven by heat given off by oxidation reactions that take place on the catalyst surface. As a result, non-equilibrium products are expected to be similar to products observed in pyrolysis.…”

Ethanol Dehydration to Ethylene in a Stratified Autothermal Millisecond Reactor

“…At a CH 4 /O 2 ratio of 1.4, the highest autothermal conversion of ethanol, 95 %, occurred in the series ethanol feed reactor, yet less than 5 % of ethanol was converted to acetaldehyde. At all other CH 4 /O 2 ratios examined, less than 1 % of ethanol was converted to acetaldehyde.…”

“…A second set of autothermal experiments consisting of an upstream methane feed and an ethanol side feed was performed to examine the effect of methane catalytic partial oxidation at various CH 4 /O 2 ratios on downstream ethanol conversion and product selectivities. Methane, oxygen, and nitrogen were fed upstream of the noble metal layer while ethanol was fed through a side port downstream of the noble metal layer.…”