Influence of temperature and particle size on structural characteristics of chars from beechwood pyrolysis

This work investigates the effect of temperature and particle size on the product yields and structure of chars obtained from the pyrolysis of Beechwood Chips (BWC), a lignocellulosic biomass. BWC of three different size fractions (0.21–0.50 mm, 0.85–1.70 mm and 2.06–3.15 mm) were pyrolyzed at atmospheric pressure and temperatures ranging from 300 to 900 °C in a fixed bed reactor. Tar and gas yields increased with increasing temperature, while char yield decreased, particularly between 300 and 450 °C. The effect of particle size was mostly observed at temperatures lower than 400 °C as a larger char yield for larger particles due to intraparticle reactions. At higher temperatures the larger surface area in the char fixed bed favoured reactions increasing char and gas yields from the smaller particles. Pyrolysis chars were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy. Loss in oxygenated functional groups and aliphatic side chains with increasing temperature was revealed, along with an increase in the concentration of large aromatic systems, leading to a more ordered char structure but no significant graphitization. The changes in char nature at high temperature led to a loss in their combustion reactivity. Raman spectra indicated that the temperature needed to completely decompose the cellulose structure increased with biomass particle size and the enhanced intraparticle reactions in pyrolysis of large particles was likely to give rise to amorphous carbon structures with small fused ring systems

The Investigation of NOx Formation and Reduction during O2/CO2 Combustion of Raw Coal and Coal Char

AbstractThis study investigated the behavior of NOx emissions during combustion of pulverized coal char and pulverized raw coal in O2/CO2 environments under nearly isothermal condition in a drop tube furnace. A representative Chinese coal Ling Nancang (LNC) and LNC CO2-char (made in CO2 condition) were studied with four different excess oxygen ratios (α=0.6, 0.8, 1.2, and 1.4). Combustion experiments were performed with an elevated concentration (850ppm) of NO. When α increased from 0.6 to 1.4, the total amount of NOx reduction was increased in both pulverized coal and char combustion. To investigate the effects of coal and char on NOx reburn reactions, LNC coal char and the raw coal combustion experiments were also performed under three high background NO concentrations (400, 850, and 1200ppm) in O2/CO2 atmosphere. During experiments with elevated NO concentrations, there was an increase in net NO reduction; however, there was also a decrease in the calculated NO reduction ratio

Localisation of an Unknown Number of Land Mines Using a Network of Vapour Detectors

We consider the problem of localising an unknown number of land mines using concentration information provided by a wireless sensor network. A number of vapour sensors/detectors, deployed in the region of interest, are able to detect the concentration of the explosive vapours, emanating from buried land mines. The collected data is communicated to a fusion centre. Using a model for the transport of the explosive chemicals in the air, we determine the unknown number of sources using a Principal Component Analysis (PCA)-based technique. We also formulate the inverse problem of determining the positions and emission rates of the land mines using concentration measurements provided by the wireless sensor network. We present a solution for this problem based on a probabilistic Bayesian technique using a Markov chain Monte Carlo sampling scheme, and we compare it to the least squares optimisation approach. Experiments conducted on simulated data show the effectiveness of the proposed approach

Life Cycle Assessment of Biochar Preparation of Chinese Traditional Medicine Residue by Low-temperature Pyrolysis

This study aimed to evaluate the environmental impacts of the biochar production process through low-temperature pyrolysis of Chinese medicine residue via life cycle assessment (LCA). An LCA model consisting of biomass pretreatment, pyrolysis, separation and cooling was developed. The results indicated that the low-temperature pyrolysis process has the highest environmental impact on AP and GWP. The consumption and direct emission of pyrolysis process were the primary sources of environmental impact. In addition, by comparing to the traditional landfill process of Chinese medicine residue, it turns out that the low-temperature pyrolysis process has improved environmental protection performance

WISCO’s Low-carbon Transformation Based On LEAP And Scenario Analysis

The paper takes Wuhan Iron and Steel Co., Ltd. (hereinafter referred to as “ WISCO “) energy consumption and carbon emissions as the research object, and analyzes WISCO’s carbon emissions. Through the construction of WISCO’s Long range Energy Alternatives Planning system (hereinafter referred to as LEAP) prediction model for energy consumption and carbon emissions, three scenarios have been set up: a baseline scenario, an energy efficiency improvement scenario, and an energy structure change scenario to measure WISCO’s carbon emissions. Based on the results of the LEAP model, this article puts forward the following recommendations for WISCO’s low-carbon transformation. WISCO must strictly control steel output.WISCO should introduce electric furnaces to increase the proportion of electric furnace steel. While ensuring the supply of scrap steel resources, WISCO ought to use scrap steel efficiently. In addition, introduction of hydrogen direct reduction iron technology is also crucial to WISCO in a planned way

Activating the Smart Future: Customer Incentives in the Transforming Energy Market

Background: Pressure from volatile fossil fuel prices, an increased awareness of climate change and technological advances has resulted in a changing relationship between utility companies and their customers and has created a demand for more efficient and controllable electricity products and services. Smart services are seen as a tool to meet the demands of the market and to encourage consumers to take more control of their energy usage. However, smart services are still in their infancy and knowledge of how to encourage their adoption in Sweden and therefore stimulate Swedish consumers to take a more active role in electricity consumption is insufficient. Purpose: This is a mixed method study of residential and commercial electricity consumers in Sweden. The purpose is to assist E.ON in meeting the demands of the transforming energy market by collecting and analyzing data concerning the awareness, drivers and willingness of consumers to adopt smart services, and to suggest incentives that could encourage consumer engagement with electricity use, including market segmentation of residential consumers. Method: This study uses a mixed method analysis. Primary data for residential Swedish electricity consumers was collected through 528 completed questionnaires whereas interviews were conducted with representatives from ISS Facility Services, Sony Mobile Communications and Midroc Property Development in order to obtain a commercial perspective on smart services. Conclusions: This study suggests that there is currently a very low level of awareness of smart services both in the residential and commercial sectors but that despite this a high proportion of respondents are willing to adopt smart services at some level with the ability to monitor energy use in real time being the most popular. Cost was identified as the most important consumer driver to adopt smart services and ultimately change energy consuming behavior but the ability to control ones energy use and environmental considerations were also significant drivers. Trust in the utility company was recognized as the most significant barrier to smart service adoption. However, the level of knowledge about smart services showed a positive correlation with consumers’ willingness to adopt smart services suggesting that barriers can be broken down by information. A residential consumer market segmentation matrix was constructed from which tailored incentives were derived to cater to the increasingly heterogeneous market. Commercial consumers were more receptive than residential consumers and put more significance of the environmental benefits of smart services however, cost still remained a decisive issue. Incentives must be specific to the size and type of commercial consumer with simplicity and customer support being desired

Migration and Transformation of Vanadium and Nickel in High Sulfur Petroleum Coke during Gasification Processes

The volatilization characteristics and occurrence forms of V and Ni in petroleum coke (petcoke) were investigated during steam (H2O) and carbon dioxide (CO2) gasification on a fixed bed reactor at 800–1100 °C. The Tessier sequential chemical extraction procedure was employed to determine the different forms of V and Ni. The results showed their volatilities were not dependent on the gasification atmosphere, but rather relied mainly on the reaction temperature. The CO2 atmosphere accelerated the conversion of organic-bound nickel to residual form at low temperature and promoted Fe-Mn oxides formation at high temperature. However, the H2O atmosphere was conducive to form vanadium bound to Fe-Mn oxides and promoted the decomposition of residual forms. In addition, the thermodynamic equilibrium calculations showed the volatilization of Ni mainly released Ni3S2 between 800–1100 °C. The H2O atmosphere was favorable to generate the more stable NixSy compound, thereby suppressing the volatilization of Ni, while the presence of CO2 led to an increase in residual V and decrease of Fe-Mn oxides. The V and Ni mainly caused erosion problems under the CO2 atmosphere while the fouling and slagging obviously increased under the H2O atmosphere with impacts gradually weakened with the increase of temperature

Fabrication of the Hierarchical HZSM-5 Membrane with Tunable Mesoporosity for Catalytic Cracking of n-Dodecane

Hierarchical HZSM-5 membranes were prepared on the inner wall of stainless steel tubes, using amphiphilic organosilane (TPOAC) and mesitylene (TMB) as a meso-porogen and a swelling agent, respectively. The mesoporosity of the HZSM-5 membranes were tailored via formulating the TPOAC/Tetraethylorthosilicate (TPOAC/TEOS) ratio and TMB/TPOAC ratio, in synthesis gel, and the prepared membranes were systematically characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption–desorption, N2 permeation, inductively coupled plasma (ICP), in situ fourier transform infrared (FT-IR), ammonia temperature-programmed desorption (NH3-TPD), etc. It was found that the increase of the TPOAC/TEOS ratio promoted a specific surface area and diffusivity of the HZSM-5 membranes, as well as decreased acidity; the increase of the TMB/TPOAC ratios led to an enlargement of the mesopore size and diffusivity of the membranes, but with constant acid properties. The catalytic performance of the prepared HZSM-5 membranes was tested using the catalytic cracking of supercritical n-dodecane (500 °C, 4 MPa) as a model reaction. The hierarchical membrane with the TPOAC/TEOS ratio of 0.1 and TMB/TPOAC ratio of 2, exhibited superior catalytic performances with the highest activity of up to 13% improvement and the lowest deactivation rate (nearly a half), compared with the microporous HZSM-5 membrane, due to the benefits of suitable acidity, together with enhanced diffusivity of n-dodecane and cracking products