基于PLC的烟气道生产线自动化研究

针对目前国内烟气道行业生产工艺落后、制造设备功能单一且自动化程度低等问题,对水泥烟气道产品的制造原料、养护工艺、成型模具以及自动化控制系统等方面进行了研究,对生产环节的可选工艺和设备及其自动化实现方案进行了比较分析。提出了一种以普通硅酸盐水泥作为原料而通过震动抽水并用蒸汽养护的生产工艺;改良设计了模具使其内外模分开,内模是可缩放的而外模亦可调整;开发出了基于激光测距传感器的识别技术对线上外模进行自动识别。生产效果表明,基于PLC(可编程控制器)的控制系统使生产线实现了机电液气一体化的自动化生产,一条生产线上能同时生产数种型号产品,能以每小时最少15根的快节拍生产,提高了生产效率和产品质量稳定性,降低了人工劳动强度和长期生产成本。

装配式出屋面烟气道在传统建筑中的应用

烟气道现场预制或拼装,成品整体观感良好,结构尺寸符合要求,强度符合质量要求;成品安装速度快,与主体连接良好,稳定性强;相较于传统砌筑烟气道,施工工期缩短,结构稳定性明显提高,成品烟气道防水性能良好。结合现场工程,对两个传统建筑工程进行装配式出屋面烟气道生产和安装施工:一个是采用现场研制的钢模体系对出屋面烟气道及盖板进行现场混凝土预制;另一个是采用建筑用轻质隔墙条板进行现场拼装。

新型预制烟气道基座及其安装方法

本新型烟气道基座提供的预制烟气道基座改变了预制烟气道的安装方式,相比传统吊洞方式安装预制烟气道,使整体结构更加稳定,规避了渗漏风险,节约了大量的人力和物力,降低了施工成本,值得在建筑工程中广泛应用。

一种住宅建筑出屋面烟气道定制预制钢模的应用

本文结合兰州市城中村改造滩尖子安置点10#、11#地块住宅小区B区一标段工程中对传统砌筑式出屋面烟气道的改进,介绍了使用预制钢模进行出屋面烟气道的加工安装过程。通过实践检验,工艺可靠,效果良好,保证了工程的施工质量。

煤制活性焦性质对其脱除烟道气中二氧化硫性能的影响(英文)

讨论了四种煤制活性焦的性质对其脱除烟道气中SO2 性能的影响。活性焦的表面碱性与微孔面积决定了其对烟道气中SO2 的吸附与氧化。生成的硫酸主要贮存在活性焦的微孔内。活性焦内的硫酸在脱附温度为 30

Water-stable ZIF-300/Ultrason? mixed-matrix membranes for selective CO_2 capture from humid post combustion flue gas

Water stable mixed-matrix membranes(MMMs) were developed to help control the global warming by capturing and sequestrating carbon dioxide(CO_2) from post-combustion flue gas originated from burning of fossil fuels.MMMs of different compositions were prepared by doping glassy polymer Ultrason? S 6010(US) with nanocrystals of zeolitic imidazolate frameworks(ZIF-300) in varying degrees. Solution-casting technique was used to fabricate various MMMs to optimize their CO_2 capturing performance from both dry and wet gases. The prepared composite membranes indicated enhanced filler-polymer interfacial adhesion, consistent distribution of nanofiller, and thermally established matrix configuration. CO_2 permeability of the membranes was enhanced as demonstrated by gas sorption and permeation experiments performed under both dry and wet conditions. As compared to neat Ultrason? membrane, CO_2 permeability of the composite membrane doped with 40 wt% ZIF-300 nanocrystals was increased by four times without disturbing CO_2/N_2 ideal selectivity. In contrast to majority of previously reported membranes, key features of the fabricated MMMs include their structural stability under humid conditions coupled with better and unaffected gas separation performance.

The FCC Flue Gas SOx Transfer Additive RFS Developed by RIPP

The present paper introduces the development of FCC flue gas SOx transfer additives by RIPP with a brief discussion of SOx transfer mechanism. The second-generation SO transfer additives of the RFS series are RIPP＇s proprietary additives with significantly improved performances. The results of commercial tests indicate that the RFS additive can effectively control SO emission of the FCC regenerator while maintaining product yields and product quality when the additive is used in a proper concentra- tion range.

Variation of toxic pollutants emission during a feeding cycle from an updraft fixed bed gasifier for disposing rural solid waste

The variation of toxic pollutants emission during a feeding cycle was examined by field monitoring from a batch feeding updraft fixed bed gasifier for disposing rural domestic solid waste. Results showed that the content of oxygen in flue gas gradually increased, while SO_2 and HCl in flue gas decreased with time after feeding in a whole feeding cycle. Although large amount of CO was produced during the gasifying, low CO content in flue gas could be obtained after the heat treatment with an electric heating device. The distribution characteristics of dioxin congeners in flue gas indicted the re-synthesis of dioxins after flue gas heating, and the increase of oxygen promoted the synthesis of dioxins. The emission content of dioxins could meet the standard(0.1 ng I-TEQ·m^(-3),GB18458-2014) of China when the oxygen content was controlled below 8.3%. Hence, for a batch feeding gasifier,low oxygen condition should be offered by reducing air intake at the later stage of feeding cycle in order to decrease the re-synthesis of dioxins after the flue gas heating.

Performance with Respect to Flue Gas Composition of a Combined Desulfurization/Denitration Process Using Powder-Particle Fluidized Bed

A new combined desulfurization/denitration (DeSOx/DeNOx,) process was tested in this study. The process uses the so-called powder-particle fluidized bed (PPFB) as the major reactor in which a coarse DeNOx catalyst, several hundred micrometers in size, is fluidized by flue gas as the fluidization medium particles, while a continuously supplied fine DeSOx sorbent, several to tens of micrometers in diameter, is entrained with the flue gas. Ammonia for NOx reduction is fed to the bottom of the bed, thus, SOX and NOX are simultaneously removed in the single reactor. By adopting a model gas, SO2-NO-H2O-N2-air, to simulate actual flue gas in a laboratory-scale PPFB, simultaneous SO2 and NO removals were explored with respect to various gas components of flue gas. It was found that the variations of SO2 removal with concentrations (fractions) of oxygen, water vapor, SO2 and NO in flue gas are little affected by the simultaneous NOx reduction. However, the dependencies of NO removal upon such gas components are closely related to the inter-actions between DeSOx sorbent and DeNOx catalyst.

FDS analysis of smoke spreading in the tunnel with flue under fire

Based on a new type of tunnel configuration model with flue in the top of it, the paper simulated the smoke pervasion when fire happens in this type of tunnel by FDS. The results show that the setting up of the flue outlet reduces the backing up distance of combustion smoke, and the distance of people fleeing is also shortened. But under this condition the smoke density inside and outside of the two flue outlet increases evidently. However, when the exhausted fans are designed at smoking outlet, the smoke movement is accelerated and almost moved into the upper space. This configuration makes the fire smoke density outside of the flue outlet reduced greatly. When the exhausted velocity increased up to a certain critical level, the smoke concentration outside of the flue outlet will reduce at the value which is no harmonious to people＇s life. This situation will offer a relatively safe space for people fleeing, and fire rescuing can also be carried out from two directions. Therefore, this tunnel configuration mentioned in this article give a new reference mode for personnel flee, fire rescuing and tunnel maintenance.

Smoke movement in a tunnel of a running metro train on fire

Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.

Experimental investigation on solar-flue gas chimney

Flue gases exhausted from thermal power plants contain more than 50% of the fuel thermal energy. In the present work, experimental investigation was carried out to study the utilization of thermal energy in flue gases to enhance the performance of modified solar chimney consisting of Savonius wind rotor. A modified solar chimney model was designed and fabricated to carry out experimental measurement. The model consists of thermal energy conversion unit; Savonius wind rotor and a chimney. The thermal energy in the flue gas transfers to the air particles in the air channel across the absorber plate and results in upward air stream due to the buoyancy effect. With an 9 absorber area of 2.36 re＇and flue gas mass flow rate of0.18 kg/s, air velocity＇ of 4.1 m/s was achieved at the top of the thermal unit. Increasing the mass flow rate of the flue gas to 0.24 kg/s enhances the air velocity to be 4.6 m/s. The results have demonstrated the possibility＇ of utilizing the thermal energy in the waste flue gas to enhance the performance of a solar chimney and facilitate the continuous operation during the absence of the sun.

Model Analysis of Smoke Control in Long Tunnel： Findings from Hsueh-Shan Tunnel Accident in Taiwan

The common properties of risk in long tunnel fires are high temperature, extreme difficulty of evacuation, rescue urgency and obstacle to rescue operation. Therefore, a complete ventilation design is an indispensable safety measure. Hsueh-Shan Tunnel is the longest in Taiwan, the fifth longest in the world. On May 7, 2012, a serious tunnel fire caused two deaths and numerous victims suffered from smoke inhalation injury. Apart from this, there was smoking entering the cross-passages and shafts which were important for evacuation. In this research, the current ventilation system in Hsueh-Shan Tunnel was simulated with FDS （fire dynamics simulator） software, and the statistics of smoke, visibility and temperature profile were analyzed. The results of this research showed that, with the current ventilation system, the time was shorter and the distance was longer for the smoke spreading windward than in other models. Furthermore, the visibility of windward victims was more affected and the temperature above the fire source was higher than those in other systems. When the wind speed in tunnel is within 2.0-4.0 m/s, the condition for turning off the ventilation fan within 250 m upwind from the fire source can be prominently reduced to 50 m upwind from the fire source. This not only could avoid plume disturbance but also could be maintained. If victims＇ evacuation should be given the highest priority, it is recommended to straightly activate the maximum power of the fan.

Impact of individual acid flue gas components on mercury capture by heat-treated activated carbon

Elemental mercury capture on heat-treated activated carbon （TAC） was studied using a laboratory-scale fixed bed reactor. The capability of TAC to perform Hg0 capture under both N2 and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components. The results suggest that surface functional groups （SFGs） on activated carbon （AC） are vital to Hg0 capture in the absence of acid gases. Meanwhile, the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg0 capture. The presence of HC1, NO2, and NO individually in basic gases markedly enhances Hg0 capture on TAC due to the heterogeneous oxidation of Hg0 on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC. Similarly, the presence of SO2 improves Hg0 capture by about 20%. This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO2 due to catalysis on the carbon surface. Furthermore, O2 exhibits a synergistic effect on Hg0 oxidation and capture when acid gases are present in the flue gases.

Preheating Characteristics of Datong Coal in O2/CO2 and Air Atmospheres

Experimental studies were carried out to find the difference of preheating characteristics of Datong coal in O_2/CO_2 and air atmospheres by a circulating fluidized bed. It is found that pulverized coal could be both steadily preheated to above 800°C in the two different atmospheres, but the temperature distribution was more uniform along the riser in O_2/CO_2 atmosphere. During the preheating, the content of CO in the flue gas can reach 12.32% under the O_2/CO_2 atmosphere, far higher than that in air(5.94%). Simultaneously, the conversion rate of fixed carbon was higher in O_2/CO_2 atmosphere compared with that in air. It can be inferred the higher oxygen concentration and higher partial pressure of CO_2 have greatly accelerated the gasification reaction. The BET analysis indicated a number of large pores were transformed into micropores during the preheating progress, and the major contributors for overall pore volume of chars and specific surface area are the micro-pores and the mesopores with diameter ranging from 2 nm to 10 nm. The inner pore structure was more developed in O_2/CO_2 atmosphere.