An engineering-environmental-economic-energy assessment for integrated air pollutants reduction, CO2 capture and utilization exemplified by the high-gravity process.

In this study, a high-gravity (HiGee) process incorporating CO2 and NOx reduction from flue gas in a petrochemical plant coupled with petroleum coke fly ash (PCFA) treatment was established. The performance of HiGee was systematically evaluated from the engineering, environmental, economic, and energy aspects (a total of 15 key performance indicators) to establish the air pollution, energy efficiency, waste utilization nexus. The engineering performance was evaluated that lower energy consumption of 78 kWh/t-CO2 can be achieved at a capture capacity of 600 kg CO2/t-PCFA. A net emission reduction of 327.3 kg-CO2/t-PCFA could be determined based on six environmental impact indicators. A cost-benefit analysis was conducted using operating cost, product sale, carbon credit, and savings in air pollution fees to present a better technological selection compared to existing carbon capture and storage plants. The waste heat recovery from the flue gas via the HiGee process could be measured via moisture condensation and attendant elimination of white smog emissions. Retrofitted heat recovery and energy intensity up to 131.8 kJ/t-PCFA and 0.21 kWh/t-PCFA were assessed. Finally, a comprehensive analysis of the HiGee process based on three daily load scenarios of CO2 capture scale were conducted, suggesting an optimal operating condition of the HiGee for generating profitability.

Environmental Benefit Assessment for the Carbonation Process of Petroleum Coke Fly Ash in a Rotating Packed Bed.

A high-gravity carbonation process was deployed at a petrochemical plant using petroleum coke fly ash and blowdown wastewater to simultaneously mineralized CO2 and remove nitrogen oxides and particulate matters from the flue gas. With a high-gravity carbonation process, the CO2 removal efficiency was found to be 95.6%, corresponding to a capture capacity of 600 kg CO2 per day, at a gas flow rate of 1.47 m3/min under ambient temperature and pressure. Moreover, the removal efficiency of nitrogen oxides and particulate matters was 99.1% and 83.2%, respectively. After carbonation, the reacted fly ash was further utilized as supplementary cementitious materials in the blended cement mortar. The results indicated that cement with carbonated fly ash exhibited superior compressive strength (38.1 ± 2.5 MPa at 28 days in 5% substitution ratio) compared to the cement with fresh fly ash. Furthermore, the environmental benefits for the high-gravity carbonation process using fly ash were critically assessed. The energy consumption of the entire high-gravity carbonation ranged from 80 to 169 kWh/t-CO2 (0.29-0.61 GJ/t-CO2). Compared with the scenarios of business-as-usual and conventional carbon capture and storage plant, the economic benefit from the high-gravity carbonation process was approximately 90 and 74 USD per ton of CO2 fixation, respectively.

Addressing environmental sustainability of plasma vitrification technology for stabilization of municipal solid waste incineration fly ash.

Fly ash from municipal solid waste incineration is considered as a hazardous waste, which would raise great threats on environmental safety due to the inherent toxic heavy metals and organic pollutants. In this study, we applied the life cycle assessment to evaluate the thermal plasma vitrification process for stabilization of fly ash from municipal solid waste incineration. We established four scenarios: (i) plasma vitrification, including centralized and off-site plasma treatment, (ii) fuel-based vitrification, (iii) water-washing treatment followed by a rotary kiln, and (iv) conventional solidification and landfill. We found that the environmental impacts, especially toxicity to ecosystem quality and human health, could be significantly reduced by deploying plasma vitrification technology. We also found that centralized plasma vitrification facilities possessing larger treatment capabilities with clean electricity could further reduce the environmental impacts. In contrast, the water-washing treatment exhibited the highest environmental impacts due to the emissions of vaporized heavy metals. Based on the LCA and sensitivity analysis, we confirmed that the thermal plasma vitrification should be considered as an environmentally-friendly solution to sustainable treatment of fly ash from municipal solid waste incineration. Lastly, we provided several perspectives and prospects of plasma vitrification for realizing the sustainable materials management.

Development and deployment of integrated air pollution control, CO2 capture and product utilization via a high-gravity process: comprehensive performance evaluation.

In this study, a proposed integrated high-gravity technology for air pollution control, CO2 capture, and alkaline waste utilization was comprehensively evaluated from engineering, environmental, and economic perspectives. After high-gravity technology and coal fly ash (CFA) leaching processes were integrated, flue gas air emissions removal (e.g., sulfate dioxide (SO2), nitrogen oxides (NOx), total suspended particulates (TSP)) and CO2 capture were studied. The CFA, which contains calcium oxide and thus, had high alkalinity, was used as an absorbent in removing air pollution residues. To elucidate the availability of technology for pilot-scale high-gravity processes, the engineering performance, environmental impact, and economic cost were simultaneously investigated. The results indicated that the maximal CO2, SO2, NOx, and TSP removal efficiencies of 96.3 ±â€¯2.1%, 99.4 ±â€¯0.3%, 95.9 ±â€¯2.1%, and 83.4 ±â€¯2.6% were respectively achieved. Moreover, a 112 kWh/t-CO2 energy consumption for a high-gravity process was evaluated, with capture capacities of 510 kg CO2 and 0.468 kg NOx per day. In addition, the fresh, water-treated, acid-treated, and carbonated CFA was utilized as supplementary cementitious materials in the blended cement mortar. The workability, durability, and compressive strength of 5% carbonated CFA blended into cement mortar showed superior performance, i.e., 53 MPa ±2.5 MPa at 56 days. Furthermore, a higher engineering performance with a lower environmental impact and lower economic cost could potentially be evaluated to determine the best available operating condition of the high-gravity process for air pollution reduction, CO2 capture, and waste utilization.

Advances and challenges in sustainable tourism toward a green economy.

This paper provides an overview of the interrelationships between tourism and sustainability from a cross-disciplinary perspective. The current challenges and barriers in the tourism sustainability, such as high energy use, extensive water consumption and habitat destruction, are first reviewed. Then the key cross-disciplinary elements in sustainable tourism, including green energy, green transportation, green buildings, green infrastructure, green agriculture and smart technologies, are discussed. To overcome the challenges and barriers, a few implementation strategies on achieving sustainable tourism from the aspects of policy/regulation, institution, finance, technology and culture are proposed, along with the framework and details of a key performance indicator system. Finally, prospects of the potential for tourism to contribute to the transformative changes, e.g., a green economy system, are illustrated. This paper shine a light on issues of importance within sustainable tourism and encourage researchers from different disciplines in investigating the inter-relationships among community/culture, environment/ecology, and energy/water/food more broadly.

Efficacy observation on traumatic nerve injury treated with different acupuncture therapies / 中国针灸

<p><b>OBJECTIVE</b>To observe the difference in the efficacy on traumatic nerve injury among electroacupuncture, warm needling therapy and electroacupuncture plus warm needling therapy and explore the better therapeutic method.</p><p><b>METHODS</b>The electromyography (EMG) and electroneurography (ENG) of 93 cases showed traumatic nerve injury of moderate damage. According to the single blind randomization principle, they were divided into an electroacupuncture (EA) group, a warm needling therapy (WN) group and an EA plus WN group, 31 cases in each one. The main acupoints were selected from Yangming Meridian and Shaoyang Meridian corresponding to the distribution of damaged nerves. EA, WN and EA plus WN were applied separately. The treatment was given once every day, 15 treatments made one session. After 3 sessions of treatment (45 treatments in total), EMG and ENG were re-checked and the results were analyzed statistically.</p><p><b>RESULTS</b>Regarding the total effective rate and effective rate, it was 96. 8% (30/31) in the EA plus WN group, which was better than 74.2% (23/31) in the EA group and 77. 4% (24/31) in the WN group (P<0. 05). Concerning to the improvements of EMG, the result in the EA plus WN group was 96.8% (30/31), which was better than the other two groups [74. 2%(23/31),74. 2%(23/31)] (P<0. 05). In terms of the recovery of nerve conduction and amplitude, the results in EA plus WN group [(50.9+/-4. 6)m/s,(8. 8+/-2. 9),microVx1 000] were better than the other two groups [(43.7+/-3.1)m/s,(4. 2+/-1. 9)microV X 1 000,(43. 8+/-3. 3)m/s,(4. 5+/-2. 2)microV X 1 000] (P<0. 05).</p><p><b>CONCLUSION</b>EA combined with WN is a better therapy of acupuncture and moxibustion in the treatment of traumatic nerve injury.</p>