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A Life Cycle Assessment of Biodiesel Production
Published in Bhaskar Singh, Ramesh Oraon, Advanced Nanocatalysts for Biodiesel Production, 2023
Mariany Costa Deprá, Patrícia Arrojo da Silva, Paola Lasta, Leila Queiroz Zepka, Eduardo Jacob-Lopes
Figure 11.3 describes the main stages in the process of obtaining rapeseed biodiesel, which consists of mechanical classification (for straw removal), extraction and transesterification. Large-scale oil extraction is generally preceded by grinding and cooking the seeds to assist the oil extraction process. However, during the mechanical pressing of the seeds, a protein-rich rape cake is also generated. Chemical extraction uses a solvent derived from petroleum (hexane). However, in solvent extraction, the oil undergoes a distillation process to recover hexane, which is recycled back to the oil extraction process. In addition, in the transesterification reaction, the triglyceride molecules in the oil react with methanol in an alkaline-containing catalyst to improve the biodiesel yield (Malça et al., 2014).
Introduction
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
Many chemical reactions and processes occur in the solution state where water is the solvent. Solubility of a substance is an important chemical property, since clearly, not all substances are soluble in water and can use water as a reaction medium. The term “soluble” deserves some clarification. When a salt such as sodium chloride is said to be soluble in water, it means that moderate, visible, or measurable amounts will dissolve. Even sodium chloride has an upper limit of about 35 g per 100 mL of water at room temperature. And similarly, even sand or trichloroethylene will dissolve to a limited extent in water, especially if the volume of water is sufficiently large. So, it is preferable to say that the salt calcium phosphate is slightly soluble instead of insoluble, though use of the latter term usually outnumbers the former. Solubility rules for most inorganic compounds in water are well known and are summarized in the table below. For organic compounds, whether solid or liquid, it is best to consult the Handbook of Chemistry and Physics or Wikipedia. Solvents other than water, such as acetone, alcohol, or hexane, are usually given or listed as alternatives (Table 1.3).
Solvent Exposure and Toxic Responses
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
A number of liquid aliphatic hydrocarbons are used in relatively pure form as solvents and also are the major constituents of a number of petroleum distillate solvents. The liquid alkanes are important ingredients in gasoline, which accounts for most of the pentane and hexane used worldwide. Hexane is an inexpensive general-use solvent in solvent glues, quick-drying rubber cements, varnishes, inks, and extraction of oils from seeds.
Large scale strategy for the extraction of oil from sesame seed: scalable approach
Published in Indian Chemical Engineer, 2023
Jayeshkumar S. Mevada, Yogeshsing N. Rajput, Shaziya Chowdhary, Shirley Kokane, Faith Dias, Ranjeet B. Doke, Ravindra D. Kulkarni, Amit P. Pratap, Aniruddha B. Pandit
The crushed date seed powder of sesame seed (20 g) was packed into a cellulose thimble. The thimble packed with seed was kept in a Soxhlet extractor. Hexane was used for the extraction solvent, and 250 mL of hexane was filled in the section of the Soxhlet extractor. In the present study, hexane is used for sesame seed oil extraction as it is widely used on a commercial scale for oil extraction. The present study aims to study the effect of pretreatment as a process intensification step in ultrasound-assisted extraction. Hence, hexane is used as a solvent for oil extraction. The extraction process was executed at 75 °C for eight hours in a water bath. After the Soxhlet extraction process, the oil was recovered using a rotary evaporator (EYELA, model N-1000S-W, Tokyo, Japan) operated at 60 °C and 5 kPa. The hydrated gums were removed from the oil by heating the oil at 70–80°C for five minutes, followed by the addition of 4-5% w/v hot water (70 °C). The homogenous mixing of oil and water was carried out using a vortex for 2 min, followed by the separation of hydrated gums and oil fraction by centrifugation using a centrifuge at 6082 g force for 10 min. The total extraction yield was measured by dividing the mean amount of oil obtained per 100 g of seed on a dry weight basis. The experiments were carried out in triplicates, and the mean value was reported.
Energy from biomass and plastics recycling: a review
Published in Cogent Engineering, 2021
Samuel Oluwafikayo Adegoke, Adekunle Akanni Adeleke, Peter Pelumi Ikubanni, Chiebuka Timothy Nnodim, Ayokunle Olubusayo Balogun, Olugbenga Adebanjo Falode, Seun Olawumi Adetona
One of the physical conversion routes include solvent extraction method (Ibarra-gonzalez & Rong, 2018). Extraction is done using a screw press. In some cases, hexane is used as a solvent for extraction. Hand press and mechanical expeller have also been used with more yields from mechanical expeller up to 75–80% oil compared to the hand press with 60–65%. Of all solvent extractors, hexane is qualified to remove stanched oil contained in the expeller up to 1% remaining at 68°C, 0.5 to 0.75 mm size of seed in 8 hours reaction time and 6:1 of solvent to seed (Chakrabarti & Prasad, 2012). For instance, oil is solvent-extracted from algae while the residue from the extraction is used to produce biogas for electricity generation through anaerobic digestion. The remaining residue can be fed back to the algae pond (Lundquist et al., 2010). Table 5 shows the different conversion routes and there qualities.
Measurements show that marginal wells are a disproportionate source of methane relative to production
Published in Journal of the Air & Waste Management Association, 2020
Jacob A. Deighton, Amy Townsend-Small, Sarah J. Sturmer, Jacob Hoschouer, Laura Heldman
Some VOCs and HAPs, like benzene and the other BTEX compounds, can lead to chronic diseases such as leukemia and other cancers, neurological damage, birth defects, and hearing loss (Garcia-Gonzalez et al. 2019; McKenzie et al. 2012). In this study, the most abundant HAPs measured were heptane and hexane. Inhalation of hexane, for example, can cause neuropathy and other neurological effects (US EPA 2013). Acute exposure of heptane can lead to dizziness, nausea, and dermatitis, among other symptoms (CDC 2018). Emissions of VOCs from marginal wells may also impact human health indirectly through the formation of tropospheric ozone (Pekney et al. 2014). The level of risk from these marginal wells would depend on the ambient concentration and the exposure time, as well as the emission rate of the toxic chemical from the well in question. As previously noted, the highest risk may be to workers who routinely come in close contact with high emitting wells (Esswein et al. 2014; Goldstein et al. 2014; Harrison et al. 2016).