• Energy Research

Dimethyl ether (DME) has been categorized as a green energy source, and the demand of the DME continue increasing. In this research, we investigated the feasibility of applying self-heat recuperation technology to DME production process using indirect method and developed an innovative process for DME production process from the energy saving point of view. By installing the self-heat recuperation technology to the DME production process, the energy consumption of the thermal and separation processes can be greatly reduced.

Energy harvesting, which involves power generation from low level energies has attracted attention in Japan for online operation of sensor and electric devices. In this research, an innovative power generation system from a low temperature heat source was proposed and its possibility for energy harvesting applications was evaluated. In this system, low temperature (< Curie temperature) heat is absorbed by a paramagnetic material (e.g. Gadolinium) and this material is isothermally transformed to a ferromagnetic material at the Curie temperature. During this transformation, magnetic moment will be produced at isentropic conditions. Combining this temporary magnet with solenoid, electric power will be generated following Faraday's law of induction without any additional energy conversion, leading to efficient power generation. It can be said that this system has a large possibility as a new energy harvesting system.

Abstract Hydrogen has been widely researched as a promising alternative fuel. Steam methane reforming (SMR) coupled with pressure swing adsorption (PSA) is one of the most dominant processes for hydrogen production. In order to reduce the energy consumption, a novel energy saving SMR–PSA H 2 production process by combining heat integration technology has been put forward. In SMR section, the waste heat of reformer and water–gas-shift (WGS) reactors is recovered to pre-heat feed gas and H 2 O. In the view of exergy, a compressor is used to achieve a well heat pairing of sensible and latent heat between hot and cold streams. In PSA section, the generated adsorption heat is recovered by heat pump and reused for regeneration of sorbent. In the total process, optimal heat coupling between hot and cold streams is realized. The simulation results indicated that the SMR and PSA sections in the optimized hydrogen production process can save 55.77 kJ/mol H 2 and 6.01 kJ/mol H 2 , respectively. The total energy consumption of the novel SMR–PSA process can be reduced to 39.5% that of the conventional process.

Abstract Climate change caused by the emission of greenhouse gases (GHGs), in particular carbon dioxide, has become a critical challenge. However, high energy penalty of CO2 capture processes is still a critical bottleneck that restricts its commercial application. In this study, an advanced pressure–temperature swing adsorption (PTSA) CO2 capture process by integrating chemical heat transformer and pressure recovery is investigated to reduce energy requirement. To evaluate the energy consumption of the proposed adsorption process, experimental and numerical study were both carried out. Initially, the adsorption kinetics (i.e. adsorption isotherm, breakthrough curve and isosteric heat) of the sorbent (zeolium®F9-HA) were tested using a fixed-bed setup. Based on the obtained experimental data, the energy consumption of the advanced PTSA process was evaluated by a commercial process-simulation software (PRO/II ver. 9.1, Invensys). The simulation results indicate that the energy consumption of the proposed PTSA process decreased to 1.18 MJ/kg CO2 (approximately 40% that of the conventional PTSA process).

Abstract Biomass drying is performed mainly in rotary dryers, which occupy a large footprint. To explore the efficient drying of biomass, a fluidized bed dryer was proposed. Good circulation of biomass particles could be established in the fluidized bed without the use of inert particle or mechanical aids. The initial moisture content of the input sawdust affected its fluidization performance. For the drying of sawdust of high-moisture content, the fluidization behavior could be divided into three stages: partial fluidization, full fluidization with increasing drying rate, and full fluidization with decreasing drying rate. A high drying rate could be achieved because of the fast mass and heat transfer rate in the fluidized bed. The fluidized bed dryer has a drying performance similar to the binary mixture fluidized bed dryer but more compact, and requires no separation of dried biomass particles from the inert bed particles.

Abstract CO2 capture and storage (CCS) technology has attracted attention for the mitigation of CO2 emissions. Among the dominant CO2 capture technologies, pressure swing adsorption (PSA) is a promising alternative to amine-based absorption. However, its capture cost should be further decreased to facilitate its commercial implementation in industry. In this study, a novel low-cost PSA CO2 capture process based on self-heat recuperation technology is discussed. An energy balance of the conventional process and the proposed process is simulated and compared using a commercial process simulator (PRO/II ver. 9.1, Invensys). In the proposed PSA process, the exothermic heat of adsorption is recuperated using a reaction heat transformer (RHT) and is recirculated for adsorbent regeneration. The waste residual gas pressure can also be recovered by an expander at the top of an adsorption tower. The simulation results indicate that the energy consumption of the proposed PSA process is 40% that of the conventional process.

AbstractCO2 capture and storage (CCS) technology has attracted attention to mitigate CO2 emission. Among the dominant CO2 capture technologies, pressure swing adsorption (PSA) is a promising alternative but requires still intensive energy consumption. In this study, a novel self-heat recuperation technology has been applied to the PSA process to reduce the CO2 capture cost. The detailed energy input of the proposed process is simulated using a commercial process simulator (PRO/II, Invensys). The simulation results indicate that the heat of adsorption stage (exothermic reaction) can be significantly recovered by reaction heat transformer (RHT), and reused for adsorbent regeneration (endothermic reaction). Meanwhile, an expander is added to recover wasted pressure associated with residual gas. As a result, the energy consumption of the proposed process is reduced to 40% of that of the conventional process.

Abstract CO2 capture, storage and utilization (CCUS) is one of the dominant strategies to mitigate climate change. Absorption, adsorption, membrane, cryogenic and microalgae are the typical CO2 capture technologies, and high capture cost is still a common challenge of existing techniques. To overcome the challenge of energy consumption, hybrid CO2 capture/utilization processes have been widely researched in the last decade. In this review, the existing absorption-microalgae hybrid CO2 capture processes were summarized. The advantages and challenges of carbon capture and microalgae biotransformation integrated strategy were discussed. In the hybrid system, carbon could be more efficient utilized via microalgae in form of bicarbonate, and converted into value-added ingredients without energy-intensive regeneration. The influence factors on the absorption-microalgae hybrid system were investigated. In addition, the potential solutions to intensifying absorption-microalgae hybrid process were also put forward. Compared to the conventional CO2 absorption and microalgae fixation method, hybrid process could be a competitive alternative to capture CO2 from industrial emissions.