Assessment of the techno-economic viability of B10 synthesis from second-generation biodiesel feedstocks in Uganda

Figures & data

Table 1. Determination of the physical and chemical properties of the raw oil.

Property	Units	Test Method	Instrument used	Model number
Fatty Acid composition	%w/w	Gas chromatography	Varian GC-FID	CLARUS 480 GC
Free Fatty Acid (FFA) composition	% of oleic acid	Gas chromatography	GC-MS	CLARUS 480 GC
Acid value	mg KOH/g of oil	AOCS official method Da 14–48	Pipettes, volumetric flasks
Iodine Value	gI2 / g of oil	Aocs official method tg 1–64	Pipettes, volumetric flasks
Saponification Value	mg KOH/g of oil	AOCS Official Method Cd 3–25	Reflux condenser and conical flask
Refractive Index		ISO 6320:2000	Abbe’s Refractometer	Abbe’s Refractometer 940487
Flashpoint	^OC	ASTM D93	Persky martens closed cup	FP-261 MRC

Figure 1. Biodiesel Production from croton and castor oil (one-step process).

Figure 2. Biodiesel Production from Jatropha oil (two-step process).

Table 2. Determination of the fuel properties of the biodiesel B100.

Property	Units	Test Method	Instruments used	Model
Kinematic viscosity at 40^0C	mm^2/s	ASTM D445	Ostwald's viscometer	Ostwald’s viscometer Bs/U
Calorific value	MJ/kg	ASTM D240	Bomb calorimeter	Bomb calorimeter C200
Flashpoint	^oC	ASTM D93	Persky martens closed cup	FP-261 MRC
Specific gravity	kg/m^3	ASTM D1298	Density metre	Excellent D4 Mettler Toledo

Table 3. Parameter values used in the analysis.

Parameter	Value
Plant capacity	100 ML/y
Jatropha oil feed rate	12,199 kg/h
Castor oil feed rate	12,640 kg/h
Croton oil feed rate	12,195 kg/h
Plant lifetime	20 y
Annual plant operation	8160 h/y
Income tax (Uganda)	30%
Nominal interest rate	10%

Table 4. Estimation of equipment costs.

Name	Code	Unit Price ($)	Qty-Croton & Castor	Qty-Jatropha	Cost- Croton & Castor ($)	Cost-Jatropha ($)
Esterification reactor	RCT1	207,700	1	2	207,700	415,400
Neutralisation reactor	NEUTR	30,900	1	1	30,900	30,900
Methanol recovery tower, FAME Column, Glycerol column	MEOHCOL, GLYCRCOL, ESTRCOL, WASHCOL	6,012	5	6	30,060	36,072
Pumps (Alcohol, catalyst, feedstock, distillation bottom, methanol recovery)	PUMP1, PUMP2 PUMP3	368,087	5	10	1,840,435	3,680,870
Storage tanks	TANKS	422,400	5	5	2,112,000	2,112,000
Leaf filters	FILTER	228,200	1	1	228,200	228,200
Heaters	HX1, HX2, HX3	900	3	4	2,700	3,600
Mixers (methanol recovery, alcohol/catalyst, recycled methanol)	MIX1, MIX2, MIX3	301,100	3	6	903,300	1,806,600
Total equipment cost- Production of croton & castor oil ($) Total equipment cost- Production of jatropha oil ($)					5,355,295
						8,313,642

Table 5. Estimation of Total Capital Investment

Item	Cost- Croton & Castor ($)	Cost- Jatropha ($)
Total Purchased cost of equipment (PCE)	5,355,295	8,313, 642
Physical plant cost (PPC) = 3.4*PCE	18,208,003	28,266,383
Auxiliary plant cost (APC) = 0.45*PPC	8,193,601	12,719,872
Fixed capital investment (FCI) = PPC + APC	26,401,604	40,986,255
Working capital investment (WCI) = 0.25*FCI	6,600,401	10,246,564
Total capital investment = FCI + WCI	33,002,005	51,232,819

Table 6. Estimation of Total Operating Costs.

Item	Unit cost ($)	Qty	Total cost ($)
Direct operating costs (DOC)
(a) Raw materials
Jatropha oil	3/L	99,541,489 L	298,624,468
Croton oil	3/L	94,743,109 L	292,299,834
Castor oil	3/L	97,433,278 L	284,229,327
Methanol	0.37/kg	11,110,726 kg	4,110,969
Phosphoric acid	1.00/kg	4,740,071 kg	4,740,071
Sulphuric acid	0.20/kg	4,740,071 kg	948,014
Sodium hydroxide	0.56/kg	4,740,071 kg	2,654,440
(b) Utilities
Electricity	0.15/kWh	1,525,920 kW	228,888
Water	1.0635/m^3	58,752 m^3	62,483
(c) Other OpEx
Labour	3.087/person	25,189.92	629,748
Supervision (0.2*labour)			125,949.5
Maintenance (0.075*FCI)			1,980,120.3
A: Total Operating Cost for Jatropha Biodiesel production
Subtotal (DOC)			314,105,151
Indirect operating costs (IOC) = 0.25*DOC			78,526,288
Total operating costs (TOC) = IOC + DOC (Jatropha)			392,631,438
B: Total Operating Cost for Castor Biodiesel production
Subtotal (DOC)	307,780,517	307,780,517	307,780,517
Indirect operating costs (IOC) = 0.25*DOC Total operating costs (TOC) = IOC + DOC (Castor)			76,945,129
			384,725,646
C: Total Operating Cost for croton Biodiesel production
Subtotal (DOC)			299,710,010
Indirect operating costs (IOC) = 0.25*DOC Total operating costs (TOC) = IOC + DOC (croton)			74,927,502
			374,637,512

Table 7. Fatty acid profile for castor, croton, and jatropha oil.

Name	Carbon Chain	Percentage Quantity (%)
Fatty acid profile for Castor (Ricinus communis) oil
Ricinoleic acid	C18:1-OH	83.59
Palmitic acid	C16:0	4.46
Stearic	C18:0	4.4
Oleic acid	C18:1	0.96
Linoleic acid	C18:2	4.49
Linolenic acid	C18:3	2.1
Total saturated		8.95
Total unsaturated		91.05
Fatty acid profile for Croton megalocarpus oil
Myristric acid	C14:0	0.03
Palmitic acid	C16:0	3.49
Stearic acid	C18:0	4.34
Oleic acid	C18:1	9.11
Linoleic acid	C18:2	76.57
Linolenic acid	C18:3	5.74
Arachidic acid	C20:0	0.17
Eicosenoic acid	C20:1	0.48
Eicosadienoic acid	C20:2	0.07
Total saturated		8.03
Total Unsaturated		91.97
Fatty acid profile for Jatropha curcas oil
Myristic acid	C14:0	0.12
Palmitic acid	C16:0	15.87
Palmitoleic acid	C16:1	0.74
Stearic acid	C18:0	6.80
Oleic acid	C18.1	40.46
Linoleic acid	C18:2	33.84
Arachidic acid	C20:0	0.35
heneicosanoic	C21:0	0.20
heptadecanoic	C17:0	0.14
Total saturated		22.78
Total Unsaturated		77.22

Table 8. Characteristics of the oil.

Property	Jatropha Oil	Castor Oil	Croton Oil
Acid Value (mg KOH/g)	15.79	0.9	0.28
Iodine Value (mg/g)	105.20	84	140.6
Saponification Value (mg KOH/g oil)	192.85	170	222.5
Refractive Index at 25^oC	1.468	1.478	1.474
Flashpoint (^oC)	235	140	163
Viscosity at 40°C (mm/s^2)	4.4	4.7	2.46

Table 9. Physical and Chemical characteristics of the Biodiesel B100.

Property	Jatropha B100	Castor B100	Croton B100	ASTM Biodiesel	ASTM Petrodiesel
Kinematic viscosity at 40°C	4.8	4.9	5	1.9–6.0	1.3–4.1
Calorific Value MJ/kg	39.5	37.2	36.6	N/A	42.80–45.36
Flash Point	172	162	100	100 - 170	60 - 80
Specific Gravity	0.83	0.86	0.79	0.86–0.90	0.82–0.86

Table 10. Physical and chemical characteristics of the B10 blend.

Property	Jatropha B10	Castor B10	CrotonB10	ASTM Biodiesel	ASTM Petrodiesel
Kinematic viscosity at 40^oc(mm/s^2)	3.7	3.5	2.8000	1.9–6.0	1.3–4.1
HHV (MJ/Kg)	42.00	41.069	40.000		42.80–45.36
Flash Point (^oC)	73.00	69.00	76.00	100–170	60–80
Specific Gravity	0.8439	0.8523	0.8682	0.86–0.90	0.82–0.86

Figure 3. Variation of acid value with Methanol: FFA mole ratio at sulphuric acid concentration of 3 wt% and 7%.

Figure 4. Variation of acid value with the temperature at sulphuric acid concentration of 3 wt% Methanol: FFA mole ratio of 70:1.

Figure 5. Effect of Methanol: Oil ratio.

Figure 6. Effect of NaOH (alkali catalyst) concentration on percent conversion.

Figure 7. Effect of reaction temperature on percent conversion.

Figure 8. Net Present Value (NPV) of Biodiesel production from the different feedstocks.

Figure 9. Effect of feedstock cost on NPV for the different feedstocks.

Figure 10. Effect of biodiesel price on NPV for the different feedstocks.

Table

Stage No	Description of process for each stage	Unit/Stream (as denoted in the Process Flow Diagram)
1.	Methanol (MEOH) and NaOH catalyst (catalyst) were mixed together in a continuous stirred mixing tank.	MIX02.
2.	The mixture of methanol and catalyst was then pressurised to 58 psia and combined with a recycle stream of methanol (MEOHREC), which was fed into the transesterification reactor (REACTOR).	PUMP02, MIX03, REACTOR.
3.	Croton or castor oil (CAS-CRO) was fed to this reactor after the oil was pressurised and heated to 58psia and 35°C or 50°C (Castor or croton, respectively). Transesterification of the Castor or Croton with methanol under NaOH or KOH catalyst proceeded in the reactor.	PUMP01, HX01, REACTOR.
4.	The products of this reaction were Fatty Acid, Methyl Esters (Biodiesel), and Glycerol. The products in Stream REACOUT were then fed to a simple distillation column (COL-01), where the unreacted methanol was separated from the product stream and recycled back into the feed stream through Stream MEOHREC.	Stream REACOUT, COL-01, Stream MEOHREC.
5.	These products in Stream, PDT-01, were then cooled in a heat exchanger to 60°C for the water washing decantation stage (WASHCOL). The water-washing process used water to collect the glycerol into solution, thus aiding in separating biodiesel from the water-glycerol mixture.	PDT-01, WASHCOL.
6.	The remaining unreacted oil (OILREC), methanol-water (MEOHWAT), and biodiesel (FAME) were separated to purity in another distillation column, COL-02. The final biodiesel product was purified to 99.8% purity in the COL-02 distillation column. The byproduct glycerol in Stream WSHOUT leaving the WASHCOL unit was sent to a neutralisation tank NEUT to neutralise the alkali catalyst (NaOH) using phosphoric acid.	OILREC, MEOHWAT, COL-02, WSHOUT, NEUT.

Table

Step One: – Esterification
Stage No	Description of process for each stage	Unit (as denoted in the Process Flow Diagram)
1.	The first step was pretreatment, where the Jatropha oil feed was esterified with methanol in the presence of an acid catalyst (H2SO4). The Jatropha oil was heated to 60°C in the heat exchanger (HX-01) before entering the esterification reactor.	HX-01.
2.	The fresh methanol stream (MEOH) was combined with the H2SO4 Stream and mixed then with the recycled methanol stream (MEOH1REC).	MIX-02
3.	The resulting mixture from MIX-02 was pumped into the reactor RCT-01. In RCT-01, the reaction was carried out at 60°C, 4 bar, a 80:1 molar ratio of methanol to FFA, and 3% sulfuric acid (based on oil). All the free fatty acids in the reactor were converted to methyl esters in 112 min.	RCT-01
4.	The resulting water and acid catalyst (H2SO4) from RCT-01 were removed before proceeding to the alkali-catalyzed transesterification using glycerin as a liquid entraining agent. Recycled pure glycerin (99.9%) from glycerin purification column C-04 at 45°C and 4 bar was used in washing the reactor effluent (RCT01OUT) in the WASH-01 column. The resulting washed stream OIL2 consisted only of refined oil and the resulting methyl esters. This Stream was sent to the downstream transesterification unit.	WASH-01, Stream OIL2
5.	The bottom Stream from WASH-01 comprised unreacted methanol, glycerol, sulfuric acid, water, and traces of esters. The methanol in this Stream was recovered in COL-01. Recovered methanol stream MEOH1REC was obtained from the top of COL-01 at 28°C and 0.2 bar, with 99% recovery of the total methanol fed to the column and purity > 99% of methanol. Vacuum distillation was used to keep the temperature under 150°C as FAME and glycerol are susceptible to thermal decomposition above 250°C and 150°C, respectively. The bottom Stream of C-02 (WASTE) is composed of glycerol, methanol, sulfuric acid, and water, but due to the presence of sulfuric acid, this Stream was not reused and is treated as waste.	COL-01, C-02, stream MEOH1REC.	(A. A. Newman, L. V. Cocks, 1968), (J. Goodrum, 2002, vol 2).
Step Two: – Alkali-Transesterification
Stage No	Description of process for each stage	Unit (as denoted in the Process Flow Diagram)	References
1.	The OIL2 Stream from the pretreatment step (esterification) was mixed with the recycled oil stream (OILREC), which was heated in the heater HX-03. The outlet stream from MIX03 was pumped into the reactor RCT-02.	Stream OIL2, OILREC, HX-03, MIX03, RCT-02.
2.	The fresh methanol stream (METHANOL) was combined with the recycled methanol stream (MEOH2REC) and the anhydrous sodium hydroxide (NAOH) in the mixer MIX04.	METHANOL, MEOH2REC, MIX04.
3.	The resulted Stream from MIX04OUT was pumped into RCT-02. The reaction was carried out at a 7.5:1 molar ratio of methanol to oil, 1% sodium hydroxide (based on oil), 60°C, and 4 bar. Anhydrous NaOH was used as recommended for commercially viable alkali-catalyzed systems. In RCT-02, all reactions were performed according to the kinetics of the reactions given in [6a]. The reactions convert 99% of the oil to fatty acid methyl esters (Biodiesel).	MIX04OUT, RCT-02.	(B. Freedman, E. Pryde, T. Mounts, 1984). [6a]
4.	The methanol in stream RCT02OUT emerged from RCT-02 and was recovered in COL-02 tower. The top Stream of COL-02 with a purity of >99.9% of methanol was mixed with fresh methanol to RCT-02. Vacuum distillation was used to keep the temperature under 150°C as FAME and glycerol are susceptible to thermal decomposition above 250°C and 150°C, respectively.	RCT02OUT, RCT-02, COL-02	(A. A. Newman, L. V. Cocks, 1968), (J. Goodrum, 2002, vol 2)
5.	The bottom Stream of COL-02 containing all the FAME from the reactor was pumped by PUMP06, heated by HX-02 then washed in the water washing column WASH-02 where FAME was completely separated from the glycerol.	COL-02, PUMP06, HX-02, WASH-02
6.	The content of other compounds, such as jatropha oil, methanol, and water in the FAME were all less than 1%. The top product stream (PDT02) from (WASH-02) composed of FAME, water, and methanol was forwarded to COL-03 to purify the FAME product where water and methanol were removed. A FAME product with 99.56% purity was obtained as a final biodiesel product.	PDT02, WASH-02, COL-03
7.	The bottom Stream from WASH-02 (WSH2OUT) is proceeded to neutralisation reactor NEUTR to remove sodium hydroxide by adding pure phosphoric acid (H3PO4) with 100% purity. It is assumed that the conversion in NEUTR is 100%. The resulting Na3PO4 was removed in gravity separator (filter) DECANTER. The remaining Stream, composed mainly of glycerin with little water, methanol, and traces of oil, was entered into a distillation column COL-04 for glycerin purification, where pure glycerin obtained from the bottom (GLYCEROL) was pumped and recycled back to the washing tower (WASH-01) after it has been heated by HX-04. The remaining water, methanol, and other traces are obtained from the top of the column.	WASH-02, NEUTR, DECANTER, COL-04, WASH-01, HX-04

Table

Chemicals	Manufacturer
NaOH	Griffchem fine chemicals
KOH	Griffchem fine chemicals
n-hexane	Macron fine chemicals
Methanol	Macron fine chemicals
H2SO4	Macron fine chemicals