Team:Edinburgh/Biorefinery Appendices

Biorefinery Appendices

Appendix 1

Appendix 1 contains all the calculations used to the cost the biorefineries.

Our biorefinery economic feasibility study is based on 700 kg/h of biomass feed. As stated earlier this capacity is higher than existing pilot plants ensuring competiveness and a higher return for potential investors. It is not even higher because of the potential difficulties of procuring such high quantities of raw material, sustainably.

Lignocellulose is made up of: 15% hemicellulose, 30% lignin and 50% cellulose. The following equipment cost is based on the process flow diagram. Drawing on Sinnot (2005) we estimate the purchase cost of major equipment (based on 2004 prices).

Note: Costings have been done in pounds sterling and converted into United States dollars using a conversion rate of 1 British pound = 1.6299 U.S. dollars (30/08/2011), as it is currently the world’s reserve currency.

Cost of major equipment

Table 1, Cost of major equipment (Sinnot, 2005)

Sample Calculation of major equiptment

Sample calculation of major equipment: Calculation for size of tank 100-102: Assuming biomass density of 500 kg/m3.

=700 kg/h / 500 kg/m3 = 1.4 m3/h / 3600= 3.88 x 10^-4 m³/s

Volume=theoretical mean residence time x flow rate= 3600*3.88 x 10^ (-4) = 1.39 m3 The flexibility of our biorefinery allows for a wide range of raw materials, and therefore a wide range of densities. Taking this into account, increasing the volume by 2 m3 will allow for densities greater than 200 kg/m3. Therefore the size of tanks 100-102 is 3.3 m3.

Purchased cost = Cost Constant x size parameter ^ index

Purchased cost = £1400 x 3.3 ^ 0.55 = £ 2699.67 This calculation is applied throughout the reactor and tank sizes, based on the assumption that the pre-treatment will produce the composition of lignin, cellulose and hemicellulose outlined earlier.

Calculation for recovery column:

Bare vessel cost= £26000. Material factor= 2

Pressure factor = 1 (1 bar)

Vessel cost= £2600 x 2 x 2 = £ 52000

Cost of plate= plate cost x material factor = £200 x 1.7 = £340

Estimated number of plates: Assume 35

Total cost of plates = £340 x 35 = £11900

Total cost of column = £5200 + 11900 = £ 63,900 (Sinnot, 2005)

Total cost of purchased equipment (PCE) = £400,681 therefore $657,288

Estimation of Fixed capital cost and investment required

Note: Process type= Fluids-Solids

Table 2, Table of factorial estimating (Table 6.1, Sinnot 2004)

Total physical post (PPC) = PCE (1+f1…+f6)= £ 981,688 ($1,612,428)

Fixed capital = PPC(1+f10+f11+f12) = £ 1,374,335.51 ($ 2,257,487)

Working capital, allow 5% of fixed capital to cover the cost of the initial oxalic acid and 2-MTHF charge = £ 68716.77(actual raw material cost, further on)

Total investment required = Fixed capital + working capital = £ 1,443,052 ($ 2,370,931)

Estimation of variable costs:

Operating time: allow for plant attainment = 350 days x 80 % production = 7008 hours per year.

Assuming the minimum amount of oxalic acid and 2-MTHF needed is 40% of the feed in: 280 kg/h of oxalic acid and 35 kg/h of 2-MTHF is needed. From Table 6.4 in Sinnot, 2004 of raw materials cost:

Oxalic acid = £0.58 /kg and 2-MTHF = £4.4 / kg

Oxalic acid = £1138099 per year and 2-MTHF = £1079232 per year

Total = £2,217,331

Note: Edinburgh’s biorefinery is based on waste (recycled) biomass, and therefore we assume no initial cost for the feedstock. But this assumption might not hold in the future as bio-based materials increase in demand there may be a charge for even ‘waste’ products. However there will be transportation and sourcing costs. These will rely on gasoline prices, and should be considered in future.

Other variable costs:

Miscellaneous: 5 % of fixed capital = £68,716 ($112,720)

Table 3, Utilities cost (based on engineering assumptions and table 6.5 Sinnot ,2004):

The large amount of cooling water is for safety. We envisage locating this plant near a water reserve, so that access to unsalted water would be easy and cheap.

Total variable cost = £2,270,657 ($3,619,248)

Fixed costs:

• Maintenance : 5% of fixed capital = £ 68,716 ($ 112,685)
• Operating labour: allowing one extra man on days. If we assume 5 plus one extra at £30,000 = £ 180,000 ($ 295,184)
• Plant overheads: take as 50% of operating labour = £90,000 ($147,584)
• Laboratory: take as 30% of operating labour = £ 54,000 ($ 88,588)
• Capital charges, 6% of fixed capital (bank rate 4%) = £ 82,460 ($ 135,223)

Total fixed cost = £488,920 ($ 801,833)

Direct production cost = total fixed cost + total variable cost = £ 2,705,578 ($ 4,524,251)

Total income:

• Assuming 80% can be extracted by hydrous pyrolysis of lignin to produce phenol-

Biomass feed= 700 kg/h. Lignin comprises of 30%. Therefore 210 kg/h of lignin. Assuming 80% extraction = 168 kg/h. According to ICIS.com (chemical industry market news), phenol= 1.22 £/kg therefore 205.45 £/h. Therefore income of phenol = £ 1,439,892 ($ 2,306,800)

• Assuming Edinburgh’s synergistic method of degrading cellulose degrades 80% of cellulose to glucose.

Composition of cellulose = 50% of lignocellulose= 385 kg/h. 80% of cellulose degrades to glucose = 0.8 x 385 = 308 kg/h

Note: Our models predict enzymes working in synergy are more efficient than enzymes not. To quantify and give exact percentages is difficult because it depends the parameters of the model.

In this example system, the products are sorbitol and fructose syrup: Sorbitol- assume 80% of glucose converts to sorbitol = 0.8 x 308 = 264.4 kg/h. From alibaba.com (global chemical market trader) sorbitol = 0.32 £/kg = 78.8 £/h. Therefore total income of sorbitol per annum at 7008 h/y = £ 552,566 ($ 886,255)

Fructose syrup- assume 80% of glucose converts to fructose syrup = 0.8 x 308 = 264.4 kg/h. From alibaba.com (global chemical market trader) fructose syrup = 0.42 £/kg = 103.48 £/h. Therefore total income of fructose syrup per annum at 7008 h/y = £ 725,243

Total income = phenol + sorbitol + fructose syrup = £ 2,717,702 ( $ 4,455,630)

Projected gross profit

Equals: sales revenue- cost of goods sold = £ 2,717,702 – £ 2,217,331

= £ 500,371 ($ 820,471)

Appendix 2

This appendix is a table with the equipment list associated with the process flow diagram

References

• Sinnot RK (2005) Coulson & Richardson's chemical engineering. Vol. 6, Chemical engineering design. Oxford: Elsevier Butterworth-Heinemann.