Development of an Acid Titration for Fast Pyrolysis Oil

Abstract

Pyrolysis oil is a renewable resource derived from biomass and can be viewed as a potential crude oil substitute or extender. Pyrolysis oil has several undesirable properties, including very high acid and water contents. Because of the high acid content, pyrolysis oil will likely be blended with conventional crude oil for processing into transportation fuel, lowering the overall acid content of the mixture and mitigating the corrosivity toward refining units. Pyrolysis oil contains polar and nonpolar organics, water, and particulates. These components can be difficult to homogenize and, if left standing, may separate again. Additionally, pyrolysis oil will thicken with time as components react to form higher molecular weight products. ASTM D664 "Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration" is often used for determining the acid content of pyrolysis oils. However, ASTM D664 was developed specifically for petroleum-based lubricants. The ASTM D664 solvent system is unsuited for use with pyrolysis oil, failing to completely solubilize the pyrolysis oil and yielding unreliable results. This work addresses two related problems with pyrolysis oil. The first is obtaining and maintaining a stable, homogeneous sample for analysis that is representative of the material to be analyzed. The second issue is the development of a reliable method for the measurement of the acid concentration by titration, which is necessary to calculate the amount of pyrolysis oil that can be mixed with a crude oil and safely processed in existing refinery equipment. A simple solvent system based on ethylene glycol (ethane-1,2-diol) has been devised that produces stable, homogeneous solutions and allows for highly repeatable acid numbers on pyrolysis oil. The accuracy and precision for the modified method are both satisfactory.■ EXPERIMENTAL SECTION ASTM D664: "Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration". 6 The ASTM D664 test method A acid number titration was developed to measure the acidic properties of petroleum products and lubricants. In 2009, the method was extended to biodiesel and blends of biodiesel with the

Removal of Inorganic Impurities in the Fast Pyrolysis Bio-oil Using Sorbents at Ambient Temperature

“…The properties of the FPBO (Table ) lie within the averages of the typical properties of a FPBO, presented in parentheses, for water content (20–30 wt %), pH (2–3), density (1.1–1.3 kg dm –3 ), and viscosity (15–35 cSt) . The TAN in this sample (109 mg KOH/g) is comparable to that of the wood-based pyrolysis oils in the literature reported at an average of 97. , The inorganic elements investigated were present in the fresh oil, with their concentration decreasing in the order Ca > K > Mg > Fe > P > Na and ranging from 9.2 to 0.55 ppm, based on an average of two samples.…”

“…36 The TAN in this sample (109 mg KOH/g) is comparable to that of the wood-based pyrolysis oils in the literature reported at an average of 97. 37,38 The inorganic elements investigated were present in the fresh oil, with their concentration decreasing in the order Ca > K > Mg > Fe > P > Na and ranging from 9.2 to 0.55 ppm, based on an average of two samples. TGA was performed on the fresh FPBO using either air (Figure 2a) or N 2 (Figure 2b) flow, primarily to discover the starting temperature of devolatilization and thus the experimental limit of this study.…”

Impact of Macroporosity on Catalytic Upgrading of Fast Pyrolysis Bio‐Oil by Esterification over Silica Sulfonic Acids

“…Although the bio‐oil possessed a similar calorific value to the woodchips, the volumetric energy density of the former was significantly higher than that of the original biomass, whose density was only 600–900 kg m −3 . The bio‐oil contained 23 wt % water, typical of fast pyrolysis bio‐oil, although the total acid number (TAN) of 61.6 mg KOH g −1 measured by the Modified D664A acid number titration method was relatively low …”

On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites in solid acid catalysed esterification pretreatment of bio-oil

“…Bio-oil from thermal pyrolysis of oak woodchips was provided by the Centre for Research and Technology-Hellas (CERTH). The measurement of bio-oil acid content was carried out according to modified D664A acid number titration method [48]. Briefly, 1 g of bio-oil was added into 100 ml ethylene glycol/water solution (95:5 vol:vol), and then the mixture was titrated with 0.1 N KOH solution in 2-propanol, and the pH of the mixture was monitored by a pH meter (Jenway 3510) until pH 7 was obtained.…”