Please login first

Techno-Economic Evaluation of Biodiesel Production from Waste Cooking Oil—A Case Study of Hong Kong
Raffel Patria, Sanjib Karmee, Carol Lin

Published: 18 February 2015 by MDPI in International Journal of Molecular Sciences
MDPI, Volume 16; 10.3390/ijms16034362
Abstract: Fossil fuel shortage is a major challenge worldwide. Therefore, research is currently underway to investigate potential renewable energy sources. Biodiesel is one of the major renewable energy sources that can be obtained from oils and fats by transesterification. However, biodiesel obtained from vegetable oils as feedstock is expensive. Thus, an alternative and inexpensive feedstock such as waste cooking oil (WCO) can be used as feedstock for biodiesel production. In this project, techno-economic analyses were performed on the biodiesel production in Hong Kong using WCO as a feedstock. Three different catalysts such as acid, base, and lipase were evaluated for the biodiesel production from WCO. These economic analyses were then compared to determine the most cost-effective method for the biodiesel production. The internal rate of return (IRR) sensitivity analyses on the WCO price and biodiesel price variation are performed. Acid was found to be the most cost-effective catalyst for the biodiesel production; whereas, lipase was the most expensive catalyst for biodiesel production. In the IRR sensitivity analyses, the acid catalyst can also acquire acceptable IRR despite the variation of the WCO and biodiesel prices.
Keywords: biodiesel, Economic Evaluation, Equipment Costs, Capital Investment Costs, Internal Rate of Return (irr)

Comments on this paper Get comment updates
Soulayman Soulayman
Comments on published article
Karmee, Patria and Lin [1] used in their economic analyses of the biodiesel production from WCO in Hong Kong with acid, base and lipase catalysts the optimum reaction conditions. As reaction conditions for base catalyst production, namely: reaction temperature was 65 °C, molar ratio of oil to methanol was 1:4, reaction time was 6 h, are not optimum but they could be accepted for providing the economic analyses, the reaction conditions for acid catalyst production, namely: reaction temperature was 65 °C, molar ratio of oil to methanol was 1:4, reaction time was 6 h, are not optimum but they could not be accepted for providing the economic analyses. Reaction time for acid catalyst biodiesel production is much longer 48h [2].

The present letter is but to correct conclusions provided in [1].
2.1. First Comment
When applying the production scheme proposed in [2] on WCO using methanol and sulfuric acid, the main results of [2] were obtained. In contrast, following the proposed in [1] biodiesel production conditions using acid catalyst, namely scheme 2 entitled "Biodiesel production process using acid catalyst" and the Table 1 entitled "Operating conditions and simulation results using chemical and enzyme catalysts" in addition to the sentence which determines the reaction time "The reaction time was 6 h for chemical and enzymatic reactions" and to the sentence which determines the methanol/WCO volume ratio "5 wt % of chemical catalysts (acid/base)" the result was negative. So, the optimum conditions for acid catalyst production are those of [2] and not of [1]. As a consequence, the acidic base production conditions mentioned in [1] are underestimated. Moreover, it is mentioned in [1] that "It is assumed in this study that the plant working days are 330 days, the working time is 15 h per day, and two biodiesel batches are produced each day". So, the economic analysis based on non accurate assumptions especially regarding reaction time, biodiesel batches/day and required energy to accomplish the reaction could not lead to conclusions given in [1].

2.2. Second Comment
In [1] it mentioned clearly the used quantity of methanol and hydroxide (see Table 1 entitled "Operating conditions and simulation results using chemical and enzyme catalysts"). From Table 1 in [1] it is easy to calculate methanol/WCO volume ratio and catalyst/WCO weight ratio. These values are 16.16% and 5% wt respectively. When comparing these values with those mentioned in [3] as optimum conditions for basic catalyst biodiesel production from WCO, namely methanol/WCO volume ratio is of 18.17% and catalyst/WCO weight ratio is of 0.4%, it becomes clear that the used in [1] value for catalyst/WCO weight ratio is 12.5 times overestimated. Moreover, optimum reaction temperature is 60 °C and optimum reaction time is 2h. Thus, the used in [1] reaction time is 3 times overestimated. As a consequence, the basic base production conditions mentioned in [1] are overestimated and this fact should be taken into consideration.

2.3. Third Comment
When comparing scheme 2 entitled "Biodiesel production process using acid catalyst" with scheme 1 entitled "Biodiesel production process using base catalyst" provided in [1] the real difference in initial investment is restricted to the WCO pretreatment complex which consists of mixer, pretreatment of WCO and decanter. The base tank drawn in scheme 1 is also required in scheme 2 and indirectly hidden by adding hydroxide to the neutralization process. The mentioned WCO pretreatment complex could be totally removed using the complex of reaction 1 (see scheme 1). So, the real difference in initial investment could be made zero. As a consequence, the results provided in [1] for base and acid catalyst, namely, in Tables 2 & 3 entitled "Total equipment costs (TEC)" and "Capital investment cost (CIC)" respectively become identical.

2.4. Fourth Comment
According to optimum biodiesel production conditions for basic catalyst mentioned in [3], a pilot biodiesel production unit using base catalyst was constructed and exploited. The plant working days are 312 days, the working time is 24 h per day, and 8 biodiesel batches are produced each day. So, the proposed in [1] 2 batches/day is 4 times lower the real possibility. This argument should be considered.
2.4. Fourth Comment
According to the above mentioned comments, the provided data of [1] in Table 4 entitled "Biodiesel production cost (BPC)" should be modified with regard to required correction in items: raw material cost and electricity.

1. Karmee, S.K.; Patria, R.D.; Lin, C.S.K. Techno-economic evaluation of biodiesel production from
waste cooking oil—A case study of Hong Kong. Int. J. Mol. Sci. 2015, 16, 4362-4371; doi:10.3390/ijms16034362.
2. Canakci, M.; Van Gerpen, J. Biodiesel production via acid catalysis. Transactions of ASAE 1999, 42(5), 1203-1210; doi: 10.13031/2013.13285.
3. Soulayman, S; Mustafa, F., Hadba, A. Assessment of optimal parameters synthesis of biodiesel from frying oils wastes. ICRE'2012, 15/16 April 2012, University of A. Mira, Bejaia, Algeria.

Hannah Roberts
This has been improved in recent years! Chemistry Services

linda whiter
essay writing company
I think essay writing company is the best example of a business degree importance. I wonder who may become their most famous graduate.

babu  rao
flight tickets
to book flight tickets

April Russell
run 3
Great and useful article. Creating content regularly is very tough. Your points are motivated me to move on.
run 3 play online

martin mozart
sildenafil acheter
such an interresting article, keep informing

acheter viagra

jiya joseph
a good article..

brock lesner
nice post very nice artical

Kr Ashwin
Get to learn here how to use Bing web browser users and remove their search records and full history by selecting all or one by one.Follow this online learning tutorial delete bing browsing history and get educate about this search engine.Thank you so much for this free of cost station.

Gloriane man
Kiss Daniel showed an interest in music from an early age, and was encouraged by his father. He started his music career professionally 2013 after his tertiary education, when he came across G-Worldwide Entertainment CEO, Emperor Geezy.

nigerian newspapers today

Gloriane man
Biodiesel evolution is going way too fast and people are also working with โกลเด้นสล็อต so that they can understand it properly and can learn more things from it.

nana john
Get the opportunity to learn here how to utilize Bing web program clients and evacuate their pursuit records and full history by choosing all or one by one.Follow this web-based learning instructional exercise USA Assignment Writing Service

roblox hack
roblox robux
hey friends if you want some interesting game then try robux its amazing game ever check it out
roblox hack
hello guys roblox robux is now with some new extra amazing features with new realistics graphics
roblox hack
try [url=]get robux[/url]