Coproduction of liquids and syngas via residue oil cracking-coke gasification (RCCG) process

Due to the extinction of conventional oil resources, large portions of heavy oil will be exploited and processed in the refinery, thus in-return generating more degraded residue oil. Fluid catalytic cracking (FCC) process is unable to treat such kind of residue oil because of rapid catalyst deactivation and excessive coke deposition. Delayed coking, featured with wide feed adaptation and low investment, has been widely used for treating petroleum residues in China. Nonetheless, delayed coking has low liquid yield and produces low-value petroleum coke. As a result, a so-called residue cracking–coke gasification (RCCG) process was proposed to realize the hierarchical conversion and value-added utilization of petroleum residues. Heavy oil was first cracked in a fluidized bed reactor via contacting with the catalyst particles to maximize the liquid yield. Coke deposited on the surface of catalysts was gasified and/or combusted for catalyst regeneration. Simultaneously, high-quality syngas could be produced via coke gasification and further used as the hydrogen source for liquid oil upgrading. The regenerated hot catalysts circulated back to the cracking reactor, providing heat and also catalytic activity for heavy oil conversion. Cracking behaviors of Venezuela vacuum residue were studied in a self-designed fluidized bed reactor (Fig. 1) with spent FCC catalyst to optimize operation parameters for high liquid yield and conversion of heavy fractions. The results showed that the hydrothermal-treated FCC catalyst (A-FCC) showed reasonable activity for residue oil cracking to ensure the acceptable liquid yield and low coke formation. The residue oil conversion above 90% and liquid yield over 75 wt.% were obtained under the operation conditions of 520℃, catalyst-to-oil mass ratio of 6.17 and steam-to-oil mass ratio of 0.6 using A-FCC catalyst. Two methods of catalyst regeneration were used in batch operation, i.e., steam gasification and gasification coupled with combustion of the deposited coke on the catalyst. Steam gasification of the deposited coke was performed at 800℃ for the catalyst regeneration, and the total volume fraction of CO and H2 was up to 86 vol.%. In comparison with coke gasification, catalyst regeneration via gasification-combustion was shown to be able to shorten the required reaction time by about 40% (see Fig. 2), while the regenerated A-FCC catalyst manifested the catalytic activity similar to that of the original A-FCC catalyst. RCCG process is characterized with higher liquid yield and lower coke production than that of delayed coking, and also could process heavy feed oil and produce syngas comparing with FCC process, thus justified its technology advantages. Please click Additional Files below to see the full abstract

Air Pollution Control Policies in China: A Retrospective and Prospects

With China’s significant role on pollution emissions and related health damage, deep and up-to-date understanding of China’s air pollution policies is of worldwide relevance. Based on scientific evidence for the evolution of air pollution and the institutional background of environmental governance in China, we examine the development of air pollution control policies from the 1980s and onwards. We show that: (1) The early policies, until 2005, were ineffective at reducing emissions; (2) During 2006–2012, new instruments which interact with political incentives were introduced in the 11th Five-Year Plan, and the national goal of reducing total sulfur dioxide (SO2) emissions by 10% was achieved. However, regional compound air pollution problems dominated by fine particulate matter (PM2.5) and ground level ozone (O3) emerged and worsened; (3) After the winter-long PM2.5 episode in eastern China in 2013, air pollution control policies have been experiencing significant changes on multiple fronts. In this work we analyze the different policy changes, the drivers of changes and key factors influencing the effectiveness of policies in these three stages. Lessons derived from the policy evolution have implications for future studies, as well as further reforming the management scheme towards air quality and health risk oriented direction

Air Pollution Control Policies in China: A Retrospective and Prospects

With China’s significant role on pollution emissions and related health damage, deep and up-to-date understanding of China’s air pollution policies is of worldwide relevance. Based on scientific evidence for the evolution of air pollution and the institutional background of environmental governance in China, we examine the development of air pollution control policies from the 1980s and onwards. We show that: (1) The early policies, until 2005, were ineffective at reducing emissions; (2) During 2006–2012, new instruments which interact with political incentives were introduced in the 11th Five-Year Plan, and the national goal of reducing total sulfur dioxide (SO2) emissions by 10% was achieved. However, regional compound air pollution problems dominated by fine particulate matter (PM2.5) and ground level ozone (O3) emerged and worsened; (3) After the winter-long PM2.5 episode in eastern China in 2013, air pollution control policies have been experiencing significant changes on multiple fronts. In this work we analyze the different policy changes, the drivers of changes and key factors influencing the effectiveness of policies in these three stages. Lessons derived from the policy evolution have implications for future studies, as well as further reforming the management scheme towards air quality and health risk oriented direction

A review on biodiesel production from microalgae: Influencing parameters and recent advanced technologies

Microalgae are the important part of carbon cycle in the nature, and they could utilize the carbon resource in water and soil efficiently. The abilities of microalgae to mitigate CO2 emission and produce oil with a high productivity have been proven. Hence, this third-generation biodiesel should be popularized. This review firstly introduce the basic characteristics and application fields of microalgae. Then, the influencing parameters and recent advanced technologies for the microalgae biodiesel production have been discussed. In influencing parameters for biodiesel production section, the factors of microalgae cultivation, lipid accumulation, microalgae harvesting, and lipid extraction have been summarized. In recent advanced technologies for biodiesel production section, the microalgae cultivation systems, lipid induction technologies, microalgae harvesting technologies, and lipid extraction technologies have been reviewed. This review aims to provide useful information to help future development of efficient and commercially viable technology for microalgae-based biodiesel production

Environmental economic impact assessment in China: Problems and prospects

The use of economic valuation methods to assess environmental impacts of projects and policies has grown considerably in recent years. However, environmental valuation appears to have developed independently of regulations and practice of environmental impact assessment (EIA), despite its potential benefits to the EIA process. Environmental valuation may be useful in judging significance of impacts, determining mitigation level, comparing alternatives and generally enabling a more objective analysis of tradeoffs. In China, laws and regulations require the use of environmental valuation in EIA, but current practice lags far behind. This paper assesses the problems and prospects of introducing environmental valuation into the EIA process in China. We conduct four case studies of environmental economic impact assessment (EEIA), three of which are based on environmental impact statements of construction projects (a power plant, a wastewater treatment plant and a road construction project) and one for a regional pollution problem (wastewater irrigation). The paper demonstrates the potential usefulness of environmental valuation but also discusses several challenges to the introduction and wider use of EEIA, many of which are likely to be of relevance far beyond the Chinese context. The paper closes with suggesting some initial core elements of an EEIA guidelineEnvironmental impact assessment; Environmental valuation; China; Economic analysis

Analytical Multi-Scale Methodology for Fluidization Systems - Retrospect and Prospect

Understanding the spatio-temporal multi-scale structure of fluidization is a challenging problem. This presentation reviews our 20-year efforts on this subject, showing the roadmap that has gradually evolved from a simple idea to a systematic methodology inclusive of subsidiary, related systems and industrial applications. The strategy of establishing stability conditions through analyses of the compromise between dominant mechanisms is emphasized. The presentation concludes with prospects for further theoretical explorations and industrial applications

Environmental economic impact assessment in China: Problems and prospects

The use of economic valuation methods to assess environmental impacts of projects and policies has grown considerably in recent years. However, environmental valuation appears to have developed independently of regulations and practice of environmental impact assessment (EIA), despite its potential benefits to the EIA process. Environmental valuation may be useful in judging significance of impacts, determining mitigation level, comparing alternatives and generally enabling a more objective analysis of tradeoffs. In China, laws and regulations require the use of environmental valuation in EIA, but current practice lags far behind. This paper assesses the problems and prospects of introducing environmental valuation into the EIA process in China. We conduct four case studies of environmental economic impact assessment (EEIA), three of which are based on environmental impact statements of construction projects (a power plant, a wastewater treatment plant and a road construction project) and one for a regional pollution problem (wastewater irrigation). The paper demonstrates the potential usefulness of environmental valuation but also discusses several challenges to the introduction and wider use of EEIA, many of which are likely to be of relevance far beyond the Chinese context. The paper closes with suggesting some initial core elements of an EEIA guidelin