Improving bio-oil furans yields by thermo-catalytic reforming process investigating different feedstocks and catalysts

Santos, João Duarte Navalho (2020). Improving bio-oil furans yields by thermo-catalytic reforming process investigating different feedstocks and catalysts. University of Birmingham. Ph.D.

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Abstract

Lignocellulosic biomass is known as a second-generation biomass which means it is non-food competing. It is the most abundant renewable resource existing, and presently it is considered as a promising feedstock for the synthesis of green chemicals and biofuels for reducing transportation emissions and dependence on fossil fuels. Steel slag are by products of the steel industry, which are composed of various metal oxides promoting a catalytic effect on pyrolysis products improving their quality. It is a cheap and sustainable alternative to replace zeolites, the most common cracking catalysts.

In this research, a TCR (Thermo-Catalytic Reforming) reactor and steel slag are used to transform lignocellulosic biomass into high quality bio-oils. TCR is a combination of intermediate pyrolysis followed by a second post reforming step. Intermediate pyrolysis heats biomass to moderate temperatures between 400–500°C in the absence of oxygen, with a short vapour residence time (seconds) and moderate solid residence time (minutes). Post reforming is achieved at temperatures between 500-800°C with extended vapour and char residence times. One characteristic of the process is that the final products (bio-oil, syngas and biochar) contains a higher energy density than the original feedstock (superior than other pyrolysis technologies) having the advantage to be easily transported and stored.

Oat hulls and sugarcane bagasse were processed in the TCR working with temperatures between 400-500 ºC in the intermediate pyrolysis reactor and 500-700 ºC in the reforming unit. Steel slag were applied in the system in two different ways: 1) mixed with the biochar in the reforming unit at different mass ratios (30, 70 and 100 wt% of steel slag); 2) mixed with the feed and introduced in the intermediate pyrolysis reactor at different mass ratios (10, 20 and 30 wt% of steel slag).

The introduction of steel slag in the TCR reactor increased the H\(_2\) yield by 80.0% and consequently the HHV by 12.3% for the syngas. The steel slag also upgraded the biooil by reducing the viscosity, water content and acid number by 46.6, 55.1 and 65.7% respectively. Moreover, the HHV of the same bio-oil raised 22.0%. All these improvements make the pyrolysis oil more attractive and suitable to be used as a biofuel.

In terms of furfural and furans, the best results (2.8 and 9.8%, respectively) were achieved by introducing 100 wt% of steel slag in the reformer and using sugarcane bagasse as a feedstock.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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