Analysis of Fuel Reduction Strategies for Crude Distillation Unit

There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient furnaces and heat exchangers contribute to the problem due to higher fuel demand and higher carbon emission. In crude preheat train (CPT), fouling causes the reduction of heat transfer efficiency, which leads to higher furnace fuel consumption, and exert additional cost for heat exchanger cleaning and lost production. This thesis presents strategies to reduce fuel consumption in the furnace, which will lead to reductions of operational cost and environmental emission. The method of exergy analysis is applied to determine the baseline energy efficiency of the furnace and CPT in a crude distillation unit (CDU). The strategies consist of locating and reducing exergy lost through process modifications of the energy system and developing optimum scheduling for retrofit and/or cleaning of heat exchangers in the CPT. There are two options for achieving fuel savings in the furnace. The options are reduction of heat lost from furnace stack and enhancement of heat recovery in the CPT. The second option involves plant shutdown for overall cleaning of CPT (Case 1), online cleaning of heat exchangers (Case 2) and combined online cleaning with retrofit of high efficiency heat exchangers (Case 3). Reduction of heat loss from furnace stack contributes to the smallest cost saving of 6.44% without carbon credit. With carbon credit, the saving is increased to 6.70%. The largest energy and carbon dioxide emission savings are found from Case 3. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT) from 215oC to 227oC. Furthermore, Case 3 results in the highest percentage of cost saving by about 71% and 62% with and without carbon credit, respectively. The payback period for investment in high efficiency heat exchangers is 3 months, with carbon credit, and 4 months, without carbon credit, respectively. Thus, Case 3 is the most cost effective option for reductions of energy consumption and carbon dioxide emission in the CDU

Operational and maintenance planning of production and utility systems in process industries.

Major process industries have installed onsite the utility systems that can generate several types of utilities for meeting the utility requirements of the main production systems. A traditional sequential approach is typically used for the planning of production and utility systems. However, this approach provides suboptimal solutions because the interconnected production and utility systems are not optimised simultaneously. In this research, a general optimisation framework for the simultaneous operational and maintenance planning of utility and production systems is presented with the main purpose of reducing the energy needs and resources utilisation of the overall system. A number of industrial-inspired case studies solved show that the solutions of the proposed integrated approach provides better solutions than the solutions obtained by the sequential approach. The results reported a reduction in total costs from 5% to 32%. The reduction in total costs demonstrate that the proposed integrated approach can result in efficient operation of utility systems by avoiding unnecessary purchases of utility resources and improved utilisation of energy and material resources. In addition, the proposed integrated optimisation-based model was further improved with the presence of process uncertainty in order to address dynamic production environment in process industries. However, integrated planning problems of production and utility systems results to large mixed integer programming (MIP) model that is difficult to solve to optimality and computationally expensive. With this regards, three-stage MIP-based decomposition strategy is proposed. The computational experiments showed that the solutions of the proposed MIP-based decomposition strategy can achieve optimal or near-optimal solutions at further reduced computational time by an average magnitude of 4. Overall, the proposed optimisation framework could be used to integrate production and utility systems for effective planning management in the realistic industrial scenarios.PhD in Energy and Powe

Analysis of Fuel Reduction Strategies for Crude Distillation Unit

There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient furnaces and heat exchangers contribute to the problem due to higher fuel demand and higher carbon emission. In crude preheat train (CPT), fouling causes the reduction of heat transfer efficiency, which leads to higher furnace fuel consumption, and exert additional cost for heat exchanger cleaning and lost production. This thesis presents strategies to reduce fuel consumption in the furnace, which will lead to reductions of operational cost and environmental emission. The method of exergy analysis is applied to determine the baseline energy efficiency of the furnace and CPT in a crude distillation unit (CDU). The strategies consist of locating and reducing exergy lost through process modifications of the energy system and developing optimum scheduling for retrofit and/or cleaning of heat exchangers in the CPT. There are two options for achieving fuel savings in the furnace. The options are reduction of heat lost from furnace stack and enhancement of heat recovery in the CPT. The second option involves plant shutdown for overall cleaning of CPT (Case 1), online cleaning of heat exchangers (Case 2) and combined online cleaning with retrofit of high efficiency heat exchangers (Case 3). Reduction of heat loss from furnace stack contributes to the smallest cost saving of 6.44% without carbon credit. With carbon credit, the saving is increased to 6.70%. The largest energy and carbon dioxide emission savings are found from Case 3. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT) from 215oC to 227oC. Furthermore, Case 3 results in the highest percentage of cost saving by about 71% and 62% with and without carbon credit, respectively. The payback period for investment in high efficiency heat exchangers is 3 months, with carbon credit, and 4 months, without carbon credit, respectively. Thus, Case 3 is the most cost effective option for reductions of energy consumption and carbon dioxide emission in the CDU

Optimal fertigation for automated fertilizer blending system by minimising fertilizer cost and utility consumption

In agricultural industries, efficient nutrient and water management are crucial to saving costs maximising crop yields, and increasing profit. A fertigation system is used to irrigate sufficient nutrients and water for the growing needs of the crops. However, the water and nutrient volume needed for each crop remains unknown due to various crop phases and the dynamics of nutritional demand. Therefore, this research work presents the optimisation modeling for an Automated Fertilizer Blending System (AFBS) to minimise the operational cost of nutrients, water, and electricity. The proposed optimisation model considers for the AFBS: (i) operational status of irrigation pump and stock tanks; (ii) stocks level for nutrient and water at each stock tank; (iii) inventory level for nutrient solutions in an AFBS tank; and (iv) nutrient and water level of the plants. The mathematical model is developed as mixed-integer linear programming (MILP). The optimisation problem is modeled using GAMS v-38.2.1 and solved by CPLEX 12 with a zero-optimality gap. In conclusion, cost comparison analysis between electricity, fertilizer, and supplied water represents the optimal cost percentage in engaging with nutrient losses minimised by 30%, water runoff, and electricity costs for optimal condition-based fertigation systems

Analytical hierarchy process for automated fertigation blending system in reducing nutrient and water losses

Fertigation is one of the agricultural methods of farming techniques which is can produce high productivity crops and efficiency in using resources. This research attempt to design and select the best criteria for an Automated Fertigation Blending System (AFBS) for reducing the eutrophication problem. Eutrophication is caused by the excessive use of nutrients and water runoff into the fresh water. The criteria had been selected based on the customer requirements (CRs) from the survey. The CRs and ECs are the two criteria for the four best design alternatives using the House of Quality (HoQ) selection method. A new methodological framework that integrated the design optional consisting of an Analytical Hierarchy Process (AHP) was developed. The AHP was developed to evaluate the selection criteria in each design developed by using a pairwise-comparison matrix. Seven criteria were implied in selecting the best design, covering ease of installation, compact and portable, safety, low equipment maintenance cost, user friendly, durability, and reduce nutrient and water runoff. The best AFBS is Design 4 with the highest performance and higher score 73.7% because of its safety, durability, user friendly, compact and portable, and reduces nutrient excess and water runoff. Conclusively, this proposed framework provides the decision to select criteria and ECs for future AFBS without an extensive experiment by saving time, and money, and reducing the negative impact on sustainabilit

Emission Inventory For Area Source: Case Study In Majlis Bandaraya Melaka Bersejarah (MBMB) Region

The aim of this study is to investigate the air pollution emission and develop an emission inventory from area source in Majlis Bandaraya Melaka Bersejarah – Historical Melaka City Council (MBMB) region. The area source covers sources that are small in nature but releases air pollutants over a relatively limit area. In this case study, the area sources are residential cooking facilities, school canteens, petrol stations, car repair/garages, restaurants, open burning areas, and construction sites. The required data are obtained through questionnaire, interviews, and direct observation at sites in the region. Other related information was also obtained from validated and published data by government official publication such as Department of Statistics and Department of Environment (DoE). The calculation procedures and identification of emission factors in developing the emission inventory are based on CORINAIR Air Emission Guidebook 2013. The detailed emission data is then being plotted on the city map. The results show that fuel burning equipment from households and restaurants emitted higher air pollutants than other source categories. Overall, annual emission of Nitrogen Oxides (NOx) was about 100.22 tons/year, Carbon Monoxide (CO) was 748.63 tons/year, Sulphur Oxides (SOx) was 3.35 tons/year, Non-Methane Volatile Organic Compounds (NMVOC) was 197.10 tons/year and Particulate Matters (PM10) was 100.49 tons/year. The results from the emission inventory identified key sources of air pollution for the city will be the basis for the future Melaka City Clean Air Plan (CAP) development

Optimum Heat Exchanger Network Cleaning Schedules for Crude Distillation Unit

There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient furnaces and heat exchangers contribute to the problem due to higher fuel demand and higher carbon emission. In crude preheat train (CPT), fouling causes the reduction of heat transfer efficiency, which leads to higher furnace fuel consumption, and exert additional cost for heat exchanger cleaning and lost production. This article presents optimum scheduling for retrofit and/or cleaning of heat exchangers in the CPT. There are three cases in this study. The cases are plant shutdown for overall cleaning of CPT (Case 1), online cleaning of heat exchangers (Case 2) and combined online cleaning with retrofit of high efficiency heat exchangers (Case 3). The largest energy and carbon dioxide emission savings are found from Case 3. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT) from 215oC to 227oC. Furthermore, Case 3 results in the highest percentage of cost saving by about 71% and 62% with and without carbon credit, respectively. The payback period for investment in high efficiency heat exchangers is 3 months, with carbon credit, and 4 months, without carbon credit, respectively. Thus, Case 3 is the most cost effective option for reductions of energy consumption and carbon dioxide emission in the CDU

Exergy Analysis For Fuel Reduction Strategies In Crude Distillation Unit

Inefficient furnaces and heat exchangers contribute to the depletion of fossil fuel problem due to higher fuel demand and higher carbon emission. The method of exergy analysis is applied to the furnace and crude preheat train (CPT) in a crude distillation unit (CDU) to determine performance benchmark of the system. This paper presents exergy analysis and strategies to reduce exergy loss through process modification. The highest exergy loss was found to be located at the inlet furnace. The proposed options for fuel reduction strategies are reduction of heat loss from furnace stack and overall cleaning schedule of CPT. The feasibility and economic analysis for both options are investigated. From the results, overall cleaning schedule of CPT contributes to the highest energy saving of 5.6%. However, reduction of heat loss from furnace stack is the highest cost saving by about 6.4%

MINLP Model for Simultaneous Scheduling and Retrofit of Refinery Preheat Train

There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient heat exchangers lead to higher fuel demand and higher carbon emission. This paper presents mixed-integer nonlinear programming (MINLP) model for simultaneous cleaning and retrofit of crude preheat train (CPT) in oil refinery plant. The formulation of the model is generated and coded in General Algebraic Modeling System (GAMS). The model minimizes the cost of energy and the cost of cleaning. The model takes into account the changes in fouling rates throughout time. There are two cases for this study. The cases are online cleaning (Case 1) and simultaneous online cleaning and retrofit (Case 2). The largest energy saving are found in Case 2. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT) from 215oC to 227oC. Furthermore, Case 2 results in the highest percentage of cost saving by about 59%. The payback period for investment in high efficiency heat exchangers is 5 months. Thus, Case 2 is the most cost effective option for reductions of energy consumption in Crude Distillation Unit (CDU)