Fatty Acid Myristic Palmitic A waste, predominantly composed of triglycerides, is transported to an anaerobic digestion (AD) plant for the production of biogas. The waste contains corn oil plus 2.77 wt % of particulate impurities. At the plant, for every 10 kg of the waste that is passed through a filter into the digester, 1 kg of horse manure is added (it may be assumed that all the particulate impurities are retained by the filter and the filter retains none of the triglyceride). The fatty acid composition of corn oil is given in Table 1 and the ultimate analysis of the horse manure is given in Table 2. Table 1. Fatty acid compositions of selected feedstocks (from Li and Khanal, 2016) Fatty acid profiles of oil/fat (% wt.) Table 2. Horse manure ultimate analysis as received (%wt) Stearic Oleic Linoleic Linolenic C14:0 C16:0 C18:0 C18:1 C18:2 C18:3 C20:0 C20:1 C22:1 Atoms in Chain C 14 16 18 18 18 18 20 20 22 H 28 32 36 34 32 30 40 38 42 O 2 2 2 2 2 2 2 2 2 M/g.mol-1 228.37 256.42 284.48 282.46 Corn oil 1.94 11.00 2.10 32.46 280.45 278.43 51.36 1.14 312.53 310.51 338.57 C H O N S 54.21 6.88 35.85 2.65 0.41 CHOC-R CHO C R + 3 HO CHO C R a) The first step of AD is hydrolysis. The hydrolysis of the triglyceride wastes is represented by the equation: CHOH CHOH CHOH + 3 [R-COOH] i. ii. What is the key class of enzymes involved in this step? (1 mark) What is the name given to the compounds represented by R-COOH? (1 mark) b) Why is it advantageous to blend triglyceride waste with horse manure for anaerobic digestion? (2 marks) c) What is the mole fraction of each fatty acid in corn oil and what is the average molar mass of corn oil? (4 marks) (question continues on the next page) Arachidic Eicosenoic Erucic d) What are the average numbers of carbon (u) and hydrogen (v) atoms in a fatty acid chain (CHO2) and what are the average numbers of carbon (x) and hydrogen (y) in the corn oil triglyceride (C+H,O6)? (4 marks) e) Determine the ultimate analysis (wt %) of the combined mixture in the digester. (2 marks) f) For the feed to the digester, estimate via the Bushwell equation the methane content of the biogas (mol%) and the total biogas yield (m kg). (6 marks)