Browsing by Author "Mukherjee, Sanjay"

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    Process simulation of blue hydrogen production by upgraded sorption enhanced steam methane reforming (SE-SMR) processes
    (Elsevier, 2020-07-21) Yan, Yongliang; Thanganadar, Dhinesh; Clough, Peter T.; Mukherjee, Sanjay; Patchigolla, Kumar; Manovic, Vasilije; Anthony, Edward J.
    Clean and carbon-free hydrogen production is expected to play a vital role in future global energy transitions. In this work, six process arrangements for sorption enhanced steam methane reforming (SE-SMR) are proposed for blue H2 production: 1) SE-SMR with an air fired calciner, 2) SE-SMR with a Pressure Swing Adsorption (PSA) unit, 3) SE-SMR thermally coupled with Chemical-Looping Combustion (CLC), 4) SE-SMR+PSA+CLC, 5) SE-SMR+PSA with an oxy-fired calciner, 6) SE-SMR+PSA and indirect firing H2 combustion from the product stream recycle. The proposed process models with rigorous heat exchanger network design were simulated in Aspen Plus to understand the thermodynamic limitations in achieving the maximum CH4 conversion, H2 purity, CO2 capture efficiency, cold gas efficiency and net operating efficiency. A sensitivity study was also performed for changes in the reformer temperature, pressure, and steam to carbon (S/C) ratio to explore the optimal operating space for each case. The SE-SMR+PSA+H2 (Case 6) recycle process can achieve a maximum of 94.2% carbon capture with a trade-off in cold gas efficiency (51.3%), while a near 100% carbon capture with the maximum net efficiency of up to 76.3% is realisable by integrating CLC and PSA (Case 4) at 25 bar. Integration of oxy-fuel combustion lowered the net efficiency by 2.7% points due to the need for an air separation unit. In addition, the SE-SMR with the PSAOG process can be designed as a self-sustaining process without any additional fuel required to meet the process heat utility when the S/C ratio is ~3-3.5
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    Techno-economic assessment of waste heat recovery technologies for the food processing industry
    (MDPI, 2020-12-05) Mukherjee, Sanjay; Asthana, Abhishek; Howarth, Martin; Chowdhury, Jahedul Islam
    The food manufacturing sector is one of the most dominant consumers of energy across the globe. Food processing methods such as drying, baking, frying, malting, roasting, etc. rely heavily on the heat released from burning fossil fuels, mainly natural gas or propane. Less than half of this heat contributes to the actual processing of the product and the remaining is released to the surroundings as waste heat, primarily through exhaust gases at 150 to 250 °C. Recovering this waste heat can deliver significant fuel, cost and CO2 savings. However, selecting an appropriate sink for this waste heat is challenging due to the relatively low source temperature. This study investigates a novel application of gas-to-air low temperature waste heat recovery technology for a confectionary manufacturing process, through a range of experiments. The recovered heat is used to preheat a baking oven’s combustion air at inlet before it enters the fuel-air mixture. The investigated technology is compared with other waste heat recovery schemes involving Regenerative Organic Rankine Cycles (RORC), Vapour Absorption Refrigeration (VAR) and hot water production. The findings indicate that utilising an oven’s exhaust gases to preheat combustion air can deliver up to 33% fuel savings, provided a sufficiently large heat sink in the form of oven combustion air is available. Due to a lower investment cost, the technology also offers a payback period of only 1.57 years, which makes it financially attractive when compared to others. The studied waste heat recovery technologies can deliver a CO2 savings of 28–356 tonnes per year from a single manufacturing site. The modelling and comparison methodology, observations and outcomes of this study can be extended to a variety of low temperature food manufacturing processes.
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    Waste heat recovery integration options for commercial bakeries in a thermo-economic-environmental perspective
    (Elsevier, 2023-11-11) Chowdhury, Jahedul Islam; Asfand, Faisal; Ja’fari, Mohammad; Mukherjee, Sanjay; Balta-Ozkan, Nazmiye
    In commercial bakeries, a substantial amount of heat is exhausted which is not only a waste of useful resource, but also contributes to higher fuel consumption and carbon emissions, if not recovered. In this study, waste heat from a single oven is considered and five potential heat recovery options are investigated in a techno-economic-environmental perspective to provide essential results for integrating an appropriate technology for waste heat recovery in the commercial bakeries sector. Waste heat recovery options were selected considering the temperature profile, the waste heat source, quality and quantity of heat and the heat energy demand for the various processes in commercial bakeries. Thermodynamic, economic, and environmental models are developed to assess the heat recovery performance, cost savings and emission reduction at both design and off-design conditions. Results show that up to 286 kW of waste heat can be recovered and reused in the case of air pre-heater, which can save up to 161.93 t/year of natural gas and an equivalent cost and emission savings of $ 93,594/year and 412.5 tCO2e/year, respectively. Moreover, the earliest payback period of 0.77 years was estimated for the air pre-heater option with an estimated capital investment cost of $71,631, whereas a maximum payback period of 4.59 years was estimated for the electricity generation by the organic Rankine cycle having an estimated capital investment cost of $304,040. These results reveal that air preheating is the most energy-efficient and cost-effective option to recover the waste heat from the ovens in the bakery industry.