Yield and Characteristics of Pyrolysis Products Obtained from Schizochytrium limacinum under Different Temperature Regimes

Abstract

Pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) was used to determine the yield and chemical composition of the pyrolysis products of Schizochytrium limacinum. The pyrolysis was carried out by varying the temperature from 300 °C to 800 °C. It was found that the main decomposition temperature of Schizochytrium limacinum was 428.16 °C, at which up to 66.5% of the mass was lost. A further 18.7% mass loss then occurred in a relatively slow pace until 760.2 °C due to complete decomposition of the ash content of Schizochytrium limacinum. The pyrolysis of Schizochytrium limacinum at 700 °C produced the maximum yield (67.7%) of pyrolysis products compared to 61.2% at 400 °C. While pollutants released at 700 °C (12.3%) was much higher than that of 400 °C (2.1%). Higher temperature will lead to more pollutant (nitrogen compounds and PAHs) release, OPEN ACCESSEnergies 2013, 6 3340 which is harmful to the environment. Considering the reasonably high yield and minimum release of pollutants, a lower pyrolysis temperature (400 °C) was found to be optimum for producing biofuel from Schizochytrium limacinum.

Comparative analysis between pyrolysis products of <em>Spirulina platensis</em> biomass and its residues

“…Instead, nitrogenate is at quite high percentage showing maximum peak at 400 ºC. The increase of aliphatic and decreasing amount of oxygenate compounds in bio-oil by the increase of temperature indicate that pyrolysis is better conducted at a higher temperature despite of the requirement for further treatment to reduce oxygenated compounds (Huanga et al, 2017;Li et al, 2013). In addition, a slight difference in the weight percentage of functional group between SPR and SP pyrolysis products is observed.…”

Comparative study on thermal cracking characteristics and bio-oil production from different microalgae using Py-GC/MS

“…Which followed by a significant weight loss of 46.7% and 65.5% due to that most carbohydrates and proteins had decomposed [16] . Another decomposition peak point was found at 642.64°C (Chlorella pyrenoidosa) and 760.17°C (Schizochytrium limacinum), which can be taken as the complete decomposition temperature of each sample owing to the ash decomposition [17,[22][23] .…”

Thermal cracking products and bio-oil production from microalgae Desmodesmus sp.

“…When the cracking temperature raised from 350°C to 450°C, the relative content of the aliphatic hydrocarbon compounds decreased gradually; when the temperature raises from 450°C to 650°C, the relative content of the aliphatic hydrocarbon compounds gradually increased and reached a maximum of 13.58% at 650°C; when temperature raised from 650°C to 750°C, the relative content of the aliphatic hydrocarbon compounds was gradually reduced, possibly due to the high temperature leading to the secondary reaction of the pyrolysis product. The thermal cracking products of sample also included some fatty acid compounds, mainly from the thermal cracking of lipid in sample [4] . Table 6 showed that the fatty acid compounds were mainly long chain fatty acids, and no fatty acid compounds were produced at low temperature of 350°C; a very small amount of fatty acid compounds were detected until 450°C; at the temperature range of 450°C-550°C, the relative content of fatty acid compounds grew got a maximum of 5.59% at 550°C; while at range of 550°C-750°C, fatty acid compounds reduced.…”

“…However, this method required the microalgae with high oil content, and was highly impacted by the lipid composition and content [2] . In order to make full use of microalgae biomass, some researches focused on pyrolysis of microalgae converted into bio-fuels, which has attracted a lot of attentions because of the higher bio-oil energy density, lower nitrogen and sulfur content, and easy preservation and transportation [3,4] . With the absence of oxygen or hypoxia conditions, the biomass are heated up to 500°C or higher temperature, the macromolecules of the biomass are cut off by thermal energy, and leading to the biomass structure isomerization and decomposing into small molecules through the whole pyrolysis process [5,6] .…”

“…The products from the pyrolysis of biomass include gas, liquid and solid components. Pyrolysis can convert biomass into bio-char, bio-oil and syngas [4] .…”