Flash co-pyrolysis of biomass with polyhydroxybutyrate: Part 1. Influence on bio-oil yield, water content, heating value and the production of chemicals

Abstract

Bio-oil obtained via flash pyrolysis shows potential to be applied as a renewable fuel. However, bio-oil often contains high amounts of water, which is a major drawback for its application. The influence of a biopolymer -polyhydroxybutyrate (PHB) on the pyrolysis of willow is investigated using a semicontinuous home-built pyrolysis reactor. The flash co-pyrolysis of willow/PHB blends (w/w ratio 7:1, 3:1, 2:1 and 1:1) clearly shows particular merits: a synergetic increase in pyrolysis yield, a synergetic reduction of the water content in bio-oil, an increase in heating value, and a production of easily separable chemicals. The occurrence of synergetic interactions is observed based on a comparison between the actual pyrolysis results of the willow/PHB blends, the theoretical pyrolysis results calculated from the reference pyrolysis experiments (pure willow and pure PHB) and their respective w/w ratio. The co-pyrolysis of 1:1 willow/PHB shows the best overall results.

Flash co-pyrolysis of biomass: The influence of biopolymers

“…The occurrence of crystals is only observed after the flash co-pyrolysis of willow and PHB, and is discussed in more detail in Ref. [10]. A flowchart of the flash (co-)pyrolysis is schematically presented in Fig.…”

“…Four biopolymer options result in a lower actual amount of pyrolytic water compared with the absolute minimum amount and thus result in a synergy: PHB, PLA, potato starch and Biopearls. The flash co-pyrolysis of 1:1 willow/PHB shows the highest synergy, reaching minus 40% [10]: the absolute minimum amount of pyrolytic water for willow/PHB = [(50.06 g  18.36% + 49.94 g  0.00%)/100] = 9.19 m%, while the actual yield in pyrolyitc water is 5.52 m% (Table 2b), thus a decrease of 3.67 m% or [(3.67/ 9.19)  100] = À39.93%. The other three biopolymers (corn starch, Eastar and Solanyl) do not provide any straightforward evidence towards the occurrence of such a synergy.…”

“…The flash co-pyrolysis of willow and the biopolymers polylactic acid (PLA) and polyhydroxybutyrate (PHB), respectively, induce interactions resulting in a synergetic decrease in the amount of pyrolytic water [9,10]. Additionally, a synergetic increase in pyrolysis yield and in energy recuperation is obtained.…”

“…The synergetic effect is observed to increase along with the addition of PLA and PHB, respectively. Besides bio-oil, the flash co-pyrolysis of willow and PHB results in the production of crystals of crotonic acid, which offer added value as a source of chemicals [10]. Even though biopolymers originate from renewables and/or are biologically degradable, most of them still have to be considered as waste, since it is ecologically unacceptable to dispose of them in the environment.…”

Fast pyrolysis of heavy metal contaminated willow: Influence of the plant part

“…Flash co-pyrolysis of biomass (willow) and PLA (poly lactic acid) or PHB (poly hydroxyl butyric acid) is a potential method in reducing the high amounts of water in bio-oil, one of the drawbacks of using bio-oil as a fuel [4,5]. Short rotation willow coppice (SRC) and a synthetic biomass, a mixture of the basic biomass components (cellulose, hemi cellulose and lignin), have been investigated for the influence of potassium on their pyrolysis behaviours [3].…”