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This paper concerns on process evaluation and modification for bioethanol separation and production by applying pinch technology. Further, the paper is also focused on obtaining a most energy-efficient process among several processes. Three basic process configurations of bioethanol separation and production were selected for this study. The three separations and production systems are Othmer process, Barbet process and a separation process that operates under vacuum condition. Basically, each process is combination of Danish Distilleries process with a separation system yielding 95% (v/v) bioethanol. The production capacity of the plant is estimated about 4 x 107 litre of bioethanol 95% (v/v) per year. The result of the studies shows that the most energy efficient process among the three processes evaluated is the Othmer process, followed by the Barbet process and the process involving vacuum operation. The evaluation also shows that further energy saving can be carried for Barbet and Othmer process configuration when Tmin = 10oC for heat exchange possible.

AbstractThe gas phase resistance in a stirred cell was investigated to understand and avoid its influence on the measurement of the reaction kinetics. To validate the influence of gas phase resistance and the experimental conditions of pseudo first order reaction for Monoethanolamine (MEA) + CO2 system, low CO2 partial pressure under various inert gas pressure were employed for CO2 the absorption into 0.5, 1, 3 and 3.6M MEA solutions with H2O and ethyleneglycol as solvents, respectively. The absorption was investigated with the stirred cell based on a fall-in-pressure technique.

Abstract In this work, a novel hydrogen production process (Integrated Chemical Looping Water Splitting “ICLWS”) has been developed. The modelled process has been optimised via heat integration between the main process units. The effects of the key process variables (i.e. the oxygen carrier-to-fuel ratio, steam flow rate and discharged gas temperature) on the behaviour of the reducer and oxidiser reactors were investigated. The thermal and exergy efficiencies of the process were studied and compared against a conventional steam-methane reforming (SMR) process. Finally, the economic feasibility of the process was evaluated based on the corresponding CAPEX, OPEX and first-year plant cost per kg of the hydrogen produced. The thermal efficiency of the ICLWS process was improved by 31.1% compared to the baseline (Chemical Looping Water Splitting without heat integration) process. The hydrogen efficiency and the effective efficiencies were also higher by 11.7% and 11.9%, respectively compared to the SMR process. The sensitivity analysis showed that the oxygen carrier–to-methane and -steam ratios enhanced the discharged gas and solid conversions from both the reducer and oxidiser. Unlike for the oxidiser, the temperature of the discharged gas and solids from the reducer had an impact on the gas and solid conversion. The economic evaluation of the process indicated hydrogen production costs of $1.41 and $1.62 per kilogram of hydrogen produced for Fe-based oxygen carriers supported by ZrO2 and MgAl2O4, respectively - 14% and 1.2% lower for the SMR process H2 production costs respectively.

The over 15 million metric tonnes of carbon black produced annually emit carbon dioxide in the range of 29–79 million metric tonnes each year. With the renaissance of carbon black in many new renewable energy applications as well as the growing transportation sector, where carbon black is used as a rubber reinforcement agent in car tires, the carbon black market is expected to grow by 66% over the next 9 years. As such, it is important to better understand energy intensity and carbon dioxide emissions of carbon black production. In this work, the furnace black process is studied in detail using process models to provide insights into mass and energy balances, economics, and potential pathways for lowering the environmental impact of carbon black production. Current state-of-the-art carbon black facilities typically flare the tail gas of the carbon black reactor. While low in heating value, this tail gas contains considerable amounts of energy and flaring this tail gas leads to low overall efficiency (39.6%). The efficiency of the furnace black process can be improved if the tail gas is used to produce electricity. However, the high capital investment cost and increased operating costs make it difficult to operate electricity generation from the tail gas economically. Steam co-generation (together with electricity generation) on the other hand is shown to substantially improve energy efficiency as well as economics, provided that steam users are nearby. Steam co-generation can be achieved via back-pressure steam turbines so that the low-pressure exhaust steam (∼2 bar/120 °C) can be used locally for heating or drying purposes. Furthermore, the potential of utilizing hydrogen to reduce carbon dioxide emissions is investigated. Using hydrogen as fuel for the carbon black reactor instead of natural gas is shown to reduce the carbon dioxide footprint by 19%. However, current prices of hydrogen lead to a steep increase in the levelized cost of carbon black (47%).

AbstractA dynamic simulation model of an injection riser/pipeline/well for injection of shipped liquefied CO2 was set up using the multiphase flow simulator OLGA. Furthermore, the topside offloading process was modelled using HYSYS. The models were applied for case studies using parameters from the existing Sn∅hvit and Sleipner CO2 injection wells and reservoirs.The study quantified effects related to flow capacity (pump/compressor requirements and line sizing of the riser, pipeline and well), freezing, hydrate formation, phase change and heat transfer in the offloading and injection system.With an available injection pump discharge pressure of about 120bar, the injection capacities were predicted to about 275kg/s on Sn∅hvit and 400kg/s on Sleipner when assuming 7” ID tubing size in the well and 700 m flowline length.In the base case scenario with a 700 m buried pipeline and injection temperature of -53°C (this storage temperature on the ship, at a pressure of 7-8bar had been selected for optimum transport capacity) there is a high risk of unwanted hydrate formation and freezing in the formation and on the outer surface of the riser and pipeline. The bottomhole temperatures were predicted as low as -38 and -46°C on Sn∅hvit and Sleipner respectively when injecting at pump design rate, far beneath expected hydrate and freezing temperature of 10-12°C and -1.9°C (in salt water) respectively. Thus heating, either by topside heat exchangers and/or by utilizing the warmer sea water (5°C) via a longer injection pipeline is required to avoid problems. An alternative storage condition at -20°C and 20bar was proposed and simulated to reduce energy requirements due to heating and pressurization at the ship. The heating power was reduced by 18 MW while topside pumping power was reduced by 0.5 MW in this case.

AbstractThe aqueous absorption technology is one of the most feasible options for post combustion CO2 capture. High energy requirement is the main problem for this technology. Intercooling is possibly one of the strategies that can reduce the energy consumption in some cases. It is used in other industries like oil refineries and has a promising effect on energy use reduction. However, the effect may depend on the absorbent system used and the configuration of the process.In this study, the effect of intercooling is investigated for monoethanolamine (MEA) and diethanolamine (DEA). The results show that the best location for intercooling, based on minimizing energy requirement per kg of CO2 captured is about 1/4th to 1/5th of the height of the column from the bottom. The effect of different parameters like lean loading, amine concentration, cooling temperature, etc is investigated in this study. The results for MEA and DEA are compared to see the effect of solvent on intercooling performance.

Abstract The study compared the techno-economic performance of two CO2 separation technologies from high CO2-content natural gas, membrane and controlled freeze zone (CFZ) separation, for liquefied natural gas (LNG) production integrated CO2 sequestration. Process and economic performances of both technologies are compared based on process simulation and levelized costs, respectively. The process simulation was performed by using Aspen Hysys V11 software. The process performance results show that the CFZ-based separation process gives CO2 capture of 99.47% and hydrocarbon recovery of 95.40%. The results show better performance compared to the membrane-based with CO2 capture of 95.78% and 92.92% of hydrocarbon recovery. The LNG production process with feed gas from CFZ required 431.92 kWh/tonne-LNG, which is also a better performance than with feed gas from the membrane of 453.93 kWh/ton-LNG. From an economic perspective, the total levelized cost of LNG production, without the CO2 sequestration, is 10.27 US$/MMBtu for the CFZ-based and 8.95 US$/MMBtu for the membrane-based. Adding the CO2 sequestration process raises the total levelized cost of LNG production to 14.67 US$/MMBtu (CFZ) and 13.12 US$/MMBtu (membrane). Therefore, the East Natuna gas field's development has challenges in cost associated with bulk CO2 separation and sequestration to monetize the resources' potential.