一种用于煤气化过程监控的简便平衡组分估算方法

针对气流床气化炉的过程监控开发了一种计算气化产物平衡组成的简易估算方法。该算法主要包含一个需迭代求解的非线性方程,可求解9种可在线监控的气体组分。该算法用5种不同工业工况在水煤浆进料和干煤粉进料气化炉上进行了验证,结果表明:与基于Gibbs自由能最小化算法相比,该算法收敛性好、计算强度小且内存占有率低,计算准度符合过程监控的需要。利用本算法分析了气流床气化炉适宜作调控气化炉运行状况的气体组分选择方案:对操作在1 300~1 450℃范围内的气化炉适宜采用H_2与CH_4作为监测变量;而对操作在更高温的气化炉适宜采用有效气含量作为监测变量。

Soil Organic Carbon and Its Fractions Across Vegetation Types:Effects of Soil Mineral Surface Area and Microaggregates

Soil organic carbon(SOC)can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and the underlying mechanisms that stabilize SOC.In this study,density fractionation and acid hydrolysis were used to assess the spatial variation in SOC,the heavy fraction of organic carbon(HFOC),and the resistant organic carbon(ROC)in soils of the southern Hulun Buir region,northeastern China,and to identify the major factors that contribute to this variation.The results showed that as the contents of clay and silt particles(0–50μm)increased,both methylene blue(MB)adsorption by soil minerals and microaggregate contents increased in the 0–20 and 20–40 cm soil layers(P<0.05).Although varying with vegetation types,SOC,HFOC,and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals,and microaggregate content(P<0.05),suggesting that soil texture,the MB adsorption by soil minerals,and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.

Beneficiation of an Indian non-coking coal by column flotation

Beneficiation of non-coking coal is gaining ground in India. It not only reduces the volume of inert content to be transported to the power plant and also lowers the wear in the boiler houses. For special applications such as the fuel for integrated gasification combined cycle plant （IGCC）, the ash content in the coal should preferably be below 15 %. Indian coals are characterized by high inter-grown ash content mainly due to ＇drift origin＇ of Gondwana formation in Permian age. This warrants fine grinding of non-coking coal in order to liberate the ash forming minerals from coal macerals. A non- coking coal sample of vitrinite type from India was ground to 44 ~tm （dso） and subjected to column flotation to improve its quality. The non-coking coal analyzing 34.6 % ash, 26.2 % volatile matter, 1.3 % moisture and 37.9 % fixed carbon could be upgraded to a concentrate/froth of 14.83 % ash at 72.18 % yield by optimizing collector and frother dosages and flotation column operating parameters, namely, froth depth, superficial feed velocity and superficial air velocity. The concentrate produced by this process is suitable as fuel for IGCC in coal-to-electricity route.

Carbon dioxide insufflation during colonoscopy in deeply sedated patients

AIM:To compare the impact of carbon dioxide(CO2) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy.METHODS:Patients referred for colonoscopy were randomized to receive either CO2 or air insufflation during the procedure.Both the colonoscopist and patient were blinded to the type of gas used.During the procedure,insertion and withdrawal times,caecal intubationrates,total sedation given and capnography readings were recorded.The level of sedation and magnitude of patient discomfort during the procedure was assessed by a nurse using a visual analogue scale(VAS)(0-3).Patients then graded their level of discomfort and abdominal bloating using a similar VAS.Complications during and after the procedure were recorded.RESULTS:A total of 142 patients were randomized with 72 in the air arm and 70 in the CO2 arm.Mean age between the two study groups were similar.Insertion time to the caecum was quicker in the CO2 group at 7.3 min vs 9.9 min with air(P = 0.0083).The average withdrawal times were not significantly different between the two groups.Caecal intubation rates were 94.4% and 100% in the air and CO2 groups respectively(P = 0.012).The level of discomfort assessed by the nurse was 0.69(air) and 0.39(CO2)(P = 0.0155) and by the patient 0.82(air) and 0.46(CO2)(P = 0.0228).The level of abdominal bloating was 0.97(air) and 0.36(CO2)(P = 0.001).Capnography readings trended to be higher in the CO2 group at the commencement,caecal intubation,and conclusion of the procedure,even though this was not significantly different when compared to readings obtained during air insufflation.There were no complications in both arms.CONCLUSION:CO2 insufflation during colonoscopy is more efficacious than air,allowing quicker and better cecal intubation rates.Abdominal discomfort and bloating were significantly less with CO2 insufflation.

Novel Air Purification System for Installation in Air Handling Units： Development, Assembly and Experimental Analysis

Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.

Decomposition of Toluene as a Biomass Tar through Partial Combustion

One way for reducing tar is oxidative and thermal cracking by partial combustion of the biomass producer gas in the gas reformer. Cracking and polymerization of the tar occur simultaneously at the proximity of inverse diffusion flame. Experimental study has been performed to clarify the effect of hydrogen concentration on soot formation and the growth of polycyclic aromatic hydrocarbons. In the present study, hydrogen concentration is controlled by the small amount of hydrogen addition to the oxidizer. The main results are as follows. Soot formation is suppressed by the small amount of hydrogen addition. The suppression of soot formation is caused by higher concentration of hydrogen. Carbon yield increases by hydrogen addition since carbon content in the undetectable components by the integrated gas chromatograph decreases. In addition, the increase in carbon yield is caused mainly by the increase in carbon monoxide stemmed from reforming of high-boiling components.

Influence of multi-chemical-component aerosols on the microphysics of warm clouds in North China

An adiabatic bin-sized cloud parcel model is developed by incorporating the multi-chemical-component (MCC) aerosol effects into the UWyo single-chemical-component (SCC) parcel model. The effects of MCC aerosols on the warm cloud microphysics in North China are investigated with the model. The simulations are initialized using the data on chemical components and number size distribution of aerosols measured during the IPAC (Influence of Pollution on Aerosols and Cloud Microphysics in North China) campaign in spring 2006. It is found that the MCC aerosols in North China increase the cloud droplet number concentration (CDNC) and decrease the effective radius more efficiently than pure ammonium-sulfate aerosols. It is also shown that the MCC aerosols in North China can narrow the cloud droplet spectra (CDS) by increasing CDNC in small size and decreasing CDNC in large size. Our results indicate that aerosol chemical components and their size distributions can influence the microphysics of warm clouds, and thus affect atmospheric radiation and precipitation. This should attract more attentions in weather and climate change research in the future.