HEN OPTIMISATION FOR CRUDE OIL DISTILLATION UNIT

The need for energy saving and reduction of gas emissions makes Process Integration an attractive technology to improve energy efficiency in grassroot and retrofit designs. One very important field for energy improvement is the heat exchanger network retrofit projects, in which to maximise the existing heat recovery and at the same time keeping the payback time as short as possible. In this dissertation, retrofit Heat Exchanger Network design procedure for crude oil distillation unit is presented. The heat exchanger network ofindonesia's oil refinery is studied to improve the energy recovery and performance in the existing network. The HEN analysis begins with the data extraction from existing network. Data of heating and cooling requirement of the process are obtained from simulation and from the process plant. Cost and economic data required for the analysis is specified. From thermodynamic data obtained from extraction, composite curve is set. From the composite curve, scope of energy recovery can be determined. Pinch analysis than can be carried out base on economic data. By using incremental area efficiency, target for network design can be set. The minimum approach temperature, which is set from targeting, is used for retrofit design using network pinch method. Set of modification is carried out in SPRINT, UMIST software, to increase energy recovery of the process. The set of modification are then optimised in SRINT. The design options are compared and evaluated and the retrofit design is suggested. The suggested modification has reduced of energy at about 39% with the payback period of 6 months. The modification gives the annual total saving of 336,705 $/y with 159,167$

A review on multiple functions of ionic liquid in biodiesel production

Scarcity of petroleum and constant concern over environmental problems caused by diesel fuels has promoted production of biodiesel from renewable sources. Biodiesel synthesized from transesterification methods in the presence of acid or base catalyst or enzyme requires huge amount of solvent, particularly from alcohol to affirm high production yield. Inevitably, the process results in bulky waste that demands appropriate attention. In attempt to tackle the problem, ionic liquid has been identified to be the most potential substitute for conventional catalyst and solvent required in the biodiesel conversion. Ionic liquid that is widely known as ‘green chemical’ can be synthesized to meet reaction requirement by careful selection of anion and cations, with correct proportion of each to produce desired mixture. This paper reviews recent applications of ionic liquid in biodiesel production as catalyst, solvent and co-solvent. Since there are few ways in which ionic liquid can be categorized, this paper highlights classification of ionic liquids into two major groups; namely acidic and basic ionic liquid. Discussion on these tswo groups covers their dual- functions in biodiesel production which are as solvent or co-solvent and catalyst as well as the limitation of each group in the biodiesel production

Prediction of significant factors in the production of ethanol by ragi tapai co-culture using Taguchi methodology

Ethanol production by co-culture of ragi tapai and Saccharomyces cerevisiae from unhydrolyzed cassava starch without addition of enzymes was conducted in a 2 L batch fermentor. Taguchi’s method with orthogonal array of L8 was applied in design of experiment (DOE) and the results were analyzed using MINITAB v14 software. Seven factors: Nitrogen-phosphorus-potassium (NPK), urea, fermentation temperature, ragi tapai concentration, S. cerevisiae concentration, agitation and co-culturing time were varied at two levels for each factor. The significant factors for the production of ethanol were determined by setting S/N ratio to “larger-is-better” for high yield ethanol and “smaller-is-better” for low yield of ethanol byproducts. The optimum values obtained for each factor were similar to each other. Both have optimum factors of: Urea at 0.8 w/w%, dry ragi tapai and S. cerevisiae concentrations each at 10 w/w%, co-culturing time at 3 h gap, NPK at 0.09 w/w% and agitation speed at 100 rpm. The fermentation temperature for high ethanol yield was 35°C, whereas for the byproducts was 30°C. From the validation experiment conducted at 30°C in 10 L fermentor, the ethanol concentration obtained was 68.00 g/L, while all byproducts concentrations were below 9.00 g/L at the end of the fermentation

The use of modified polymeric polyhipe as an immobilized cell matrix

Utilization of modified-polyHIPE polymer matrix in the immobilization cell system is probably can substitute conventional cell matrix. The confined microenvironment was designed to promote the bacterium growth and its metabolic activity. The applied forced-flow seeding technique yielded a more uniform distribution of cells within the polymeric support, which also helps to improve nutrient transport. This also prevents significant growth of cells around the outer surface of matrix. The microstructure of the matrix with respect to its physico-chemical characteristics, which include appropriate pore and interconnect sizes as well as surface chemistry (i.e. hydrophobic, hydrophilic), are very important with respect to the flow of nutrients and waste material and also for cell migration. As a result, the developed immobilized matrix can be performed effectively and essential in the area of bioprocess development specifically for microbial fermentations

Cassava leaves and stems hydrolysis for glucose production

Cassava or tapioca leaves and stems are all year product that is far under researched and underutilized. It was reported that the leave contain essential minerals and nitrogen sources required by microorganisms such as yeast and other fermenting microbes for growth. In this study, cassava leave and stem were hydrolyzed using diluted acid concentration for glucose production. The research was conducted in shake flask and Taguchi’s methodology was used to study significant parameters affecting hydrolysis process. Design expert v8.0 software aided the analysis for maximum glucose production. Validation result revealed that hydrolysis of 5% (w/v) mixture of cassava stems and leaves gave maximum of glucose yield of 0.991 g/g

Single-Step Bioconversion of Unhydrolyzed Cassava Starch in the Production of Bioethanol and Its Value-Added Products

The global economic recession that began in 2008 and continued into 2009 had a profound impact on world income (as measured by GDP) and energy use. Since then the price of the energy supply by conventional crude oil and natural gas production has been fluctuating for years which has resulted in the need to explore for other alternative energy sources. One of the fastest-growing alternative energy sources is bioethanol, a renewable energy which can reduce imported oil and refined gasoline, thus creates energy security and varies energy portfolio. Global biofuel demand is projected to grow 133% by 2020 (Kosmala, 2010). However, the biofuel supply is estimated deficit by more than 32 billion liters over the same period and the deficit is worse for ethanol than biodiesel. Ethanol may serve socially desirable goals but its production cost is still remained as an issue. Extensive research has been carried out to obtain low cost raw material, efficient fermentative enzyme and organism, and optimum operating conditions for fermentation process. In addition to that, researchers have been trying to capitalize certain features of the plant equipment and facilities to increase the throughput of ethanol and other high value by products as well as to apply suitable biorefinery for the product recovery. At the same time, effort has been made to reduce utilities costs in water usage, cooling or heating, and also consumables usage via minimizing the effluent production. Aimed to provide an alternative means for ethanol production, this book chapter introduces a single-step or direct bioconversion production in a single reactor using starch fermenting or co-culture microbes. This process not only eliminates the use of enzymes to reduce the production cost but also yield added value by-products via co-culture of strains. Before further elaboration on this single-step fermentation, we will visit the conventional process, the substrate preparation and microbe used. By this way a clear picture of the differences between conventional process and the proposed single-step fermentation with the advantages and disadvantages of both processes will be discussed

Ragi tapai and Saccharomyces cerevisiae as potential coculture in viscous fermentation medium for ethanol production

A comparison study on the ethanol production from 20% (w/v) of unhydrolyzed raw cassava starch using  Saccharomyces cerevisiae and Candida tropicalis was performed and compared with the commercialized ragi tapai. The findings showed that S. cerevisiae, C. tropicalis and ragi tapai produced 23, 20 mg/l and 26 g/l of ethanol in 72 h, respectively. Subsequent coculturing of the two best performing strains namely ragi tapai and S. cerevisiae were performed to improve ethanol production and to reduce the accumulation of inhibitory concentration of reducing sugar with 10% (w/v) unhydrolyzed raw cassava starch. The coculture of ragi tapai with S. cerevisiae using the unhydrolyzed raw starch in a single step-fermentation produced an ethanol concentration of 35 g/l when the starch was inoculated with ragi tapai and cocultured with S. cerevisiae. The yield was 46% higher than the one inoculated with ragi tapai only (24 g/l). The glucose concentration was maintained at a low concentration in the coculture medium as compared to the medium with pure ragi tapai. The findings suggested that coculture of ragi tapai with S. cerevisiae is capable of enhancing the ethanol production and prevention of the inhibitory effect of reducing sugars on amylolytic activity.Key words: Cassava starch, ethanol, Candida tropicalis, ragi tapai, Saccharomyces cerevisiae, single-stepbioconversion

Investigation the efficiency of integration microbial electrolysis cell to anaerobic digester for biomethane production

The integration of Microbial electrolysis cell to anaerobic digestion has emerged as a promising solution for the upgrade of biomethane within the system. It facilitates the conversion of organic waste into biomethane without the need to CO2 capture and separation downstream processes. Recent studies have showed that modifying the electrodes has a major effect on the microbial stages, specifically hydrolysis, acidogenesis’s, which are key steps for the final stage methanogenesis. Understanding these stages in the MEC-AD system allows researchers to identify potential bottlenecks and optimize the conversion of organic matter into methane. In addition, the final stage, namely methanogenesis which is responsible for the biomethane production and upgrade, is highly affected the by the density of the methanogenic community and the diversity of the inoculum. This study investigated the effect of integrating unmodified, and modified electrodes of MEC to anaerobic digester on the two stages hydrolysis and acidogenesis, then the kinetic modelling of biomethane production with mixing two inoculums namely cow manure and effluent of a previous digester. Hybrid systems showed a higher hydrolysis efficiency especially modified systems, with a percentage of 39.4% by the 48th hour, followed by unmodified systems. The acidogenesis pathway results showed that the hybrid systems were dominated by the acetic acid pathway, which is favourable in the hybrid system, unlike the conventional digester, which was dominated by a different pathway. Mixing the original inoculum obtained from a previous AD with cow manure has enhanced and increased the competitiveness of the microbial community. Thus, it was positively reflected on the biomethane production potential and rate, with a value of 38ml/g COD and 1.2 ml/h, respectively

Improvement of conventional milling process in palm oil processing: rotary filter press

The effectiveness of the Rotary Filter Press in removing solids form the press liquor was examined and then analyzed its possibility in replacing the functions of the conventional screw press and vibrating screen. Literature review on the conventional equipment used in the mill which is Twin Screw Press was conducted. Alternative equipment, the Rotary Filter Press was proposed and its design and principal of operation were discussed. Besides, the advantages and disadvantages of both the conventional and alternative equipment were compared. It was observed that the Rotary Filter Press capable to remove some of the non-oily solids (NOS) from the press liquor but no results were obtained for the feed of Depulper mesh as the fibrous mesh often chocked the system. Therefore, several modifications were suggested to improve the efficiency of the equipment such as control of water dilution in the Depulper mesh and inclusion of perforated plates in the equipment design

Process improvement of conventional palm oil milling: continuous cooker

The objective of this study is to improve the conventional milling process in palm oil processing by replacing the function of the current used horizontal sterilizer with a Continuous Cooker. A trial study of Continuous Cooker was conducted and results showed that the cooker operated for 55 minutes using low pressure steam of 1 bar and cooking temperature of 98°C. At these operating conditions, the cooker was capable of carrying out the functions of a horizontal batch sterilizer by achieving most of the conventional sterilization purposes. This was proven by the results obtained from trial runs and laboratory analysis conducted on the equipment and its samples