某电厂燃烧器煤粉管道结构优化

随着国家环保要求的提高,目前国内电厂都在进行低氮燃烧器改造,某型低氮燃烧器作为从国外引进技术,不仅能够高效、稳定地燃烧多种燃料,而且已经作为一种经济实用的手段来满足现有的及将来日益还将严格的降低NOx排放量的需要。本文针对某电厂低氮燃烧器摆动机构断裂,煤粉管道变形,简要介绍了相关结构优化措施。

钢铁生产科技信息

现行焦炉所用粘结性高的煤，具有生产效率低、能源消耗高、环境污染严重等许多问题，使用现行焦炉模式代替寿命到期的炼焦炉，很难解决。日本开发研制了新式炼焦，并且由加入钢铁联盟的企业参与，从1994年到2002年期间实施了这个计划。

Effect of sodium sulfate on strength and microstructure of alkali-activated fly ash based geopolymer

The main objective of this paper focuses on the changes that occur in the strength and microstructural properties of sodium silicate activated fly ash based geopolymer due to varying the sulfate salt and water content.A series of tests including X-ray diffraction,Fourier transform infrared spectroscopy,scanning electron microscopy,physical adsorption and unconfined compressive strength were used to investigate this effect.The results indicate that the higher water content has an adverse effect on the alkali activation and microstructural properties of geopolymer,so the optimum mass ratio of sodium sulfate in alkali-activated geopolymer under different water-to-binder ratios shows a“peak shifting”phenomenon,i.e.,the higher the water-to-binder ratio,the higher the optimum mass ratio.Lower presence of sodium sulfate has no significant effect on the alkali-activated geopolymer systems;higher addition of sodium sulfate,however,could cause the symmetrical stretching vibration of Si—O and the symmetrical stretching vibration of Si—O—Si and Al—O—Si,and promote the formation of N-A-S-H gels.Furthermore,the cement effect of the gel and sodium sulfate aggregate could improve the integrity of pore structure obviously.The maximum strength of geopolymer curing at ambient temperature was 52 MPa.This study obtains the rule that the strength properties of alkali-activated geopolymers vary with the water-to-binder ratio and sodium sulfate content.The feasibility of geopolymer co-activated by sodium sulfate and sodium silicate was investigated,and reference for engineering application of alkali-activated geopolymer in salt-bearing areas was provided.

Improved Sorting Scheme of Microstructure of Fly Ash

Aiming at the problem of the existing sorting for microstructure of fly ash, an improved scheme was put forward in this paper. First, fly ash particles are divided into four groups as low calcium, iron, high calcium and char particle according to the substance components of fly ash. Then fly ash particles are divided into 14 sub groups, for example: cenospheres, plerospheres, solid spheres, porous char and dense char based on their chemical composition, shape and the characteristics of inner structure of fly ash. It has a distinct difference in granule configuration, inner structure and substance components. Some disadvantages of the existing scheme such as unilateralism and imprecision have been overcome in the advanced schemes.

Coal-gas interaction： implications of changes in texture and porosity

Transient sorption and desorption of helium and carbon dioxide in Upper Freeport coal powder and lumps were analyzed. Differences in texture and porosity between the powder and lumps may affect the transport and interaction of the penetrant and coal. In this work, we address macroscopic and mesoscopic structural differences between powdered and non-powdered coals that influence the rates of the gas transport kinetics and changes in coal texture （swelling, shrinkage, and changes in the pore structure and interconnectivity） and the reciprocal free-phase pressure decay （relaxation）. Com- parison of the multi-exponential relaxation time constants as a function of pressure, for CO2 and inert gas （helium）, allows us to postulate several mechanisms responsible for observed pressure decay patterns.

Effect of activator on rheological properties of alkali-activated slag-fly ash pastes

The time-dependent rheological behaviors of alkali-activated cement(AAC)are expected to be precisely controlled,in order to meet the requirements of modern engineering practices.In this paper,the effects of activator,including the Na_(2)O concentration and SiO_(2)/Na_(2)O(S/N)molar ratio,on the rheological behavior of alkali-activated slag fly ash pastes were investigated.The small amplitude oscillatory shear(SAOS)and shear test were used to evaluate the structural build-up and flowability of pastes.Besides,zeta potential measurement,calorimetric test and thermogravimetric analysis(TGA)were carried out to reveal the physico-chemical mechanisms behind the rheological evolution of fresh pastes.It was found that high Na_(2)O concentration and low S/N molar ratio improved the flowability and structural build-up rate of paste.Moreover,the structural build-up of alkali-activated slag-fly ash pastes consists of two stages,which is controlled by the dissolution of solid reactants and formation of C-(A)-S-H gels,respectively.

Microstructures and thermal properties of municipal solid waste incineration fly ash

To analyze the feasibility of utilization of thermal technology in fly ash treatment, thermal properties and microstructures of municipal solid waste incineration （MSW1） fly ash were studied by measuring the chemical element composition, specific surface area, pore sizes, functional groups, TEM image, mineralogy and DSC-TG curves of raw and sintered fly ash specimens. The results show that MSWI fly ash particles mostly have irregular shapes and non-typical pore structure, and the supersonic treatment improves the pore structure; MSWI fly ash consists of Such crystals as SiO2, CaSO4 and silica-aluminates, and some soluble salts like KCl and NaCl. During the sintering process, mineralogy changes largely and novel solid solutions are produced gradually with the rise of temperature. Therefore, the utilization of a proper thermal technology not only destructs those persistent organic toxicants but also stabilizes hazardous heavy metals in MSWI fly ash.

Experimental investigation of performance properties and agglomeration behavior of fly ash from gasification of corncobs

The gasification industries make use of biomass residue as feedstock to produce synthesis gas,but the gasification of this waste biomass generates tons of ash everyday.Performance properties and agglomeration behavior of corncob ash(CCA) collected from the gasification of corncobs in a pilot-scale gasification station were investigated by using some experimental methods.Based on the chemical composition results,the agglomeration tendency of CCA from combustion and gasification process was also analyzed.Chemical analysis shows that the fly ash is mainly composed of inorganic matters formed by K,Mg,Ca,Na,Fe,Al,S,etc.The agglomeration characteristics indicate that the slagging degree increases with the increase of ashing temperature,and the slagging tendency of these CCA samples from gasification or combustion is different with various slagging indices.All CCA samples from combustion or gasification can cause slagging/fouling problems in thermal conversion systems.The applications of CCA are closely related to its performances,and CCA has the potential to be used in various fields,for example,as a material for ceramic products and activated carbon,as an adsorbent,as a crude fertilizer,and as a structural material.

Structure and properties of forming adsorbents prepared from different particle sizes of coal fly ash

In this paper, different particle sizes of coal fly ash FA-R(D50= 15.75 μm), FA-A(D50= 3.61 μm) and FA-B(D50= 1.73 μm) were treated with Na OH solution to prepare the forming adsorbents FFA-R, FFA-A and FFA-B.The structure and adsorption properties of the forming adsorbents for methylene blue(MB) from aqueous solution were examined. The results showed that the specific surface areas and adsorption capacities of the forming adsorbent for MB increased with decreasing particle size of raw coal fly ashes. The adsorption kinetic data of MB on FFA-R, FFA-A and FFA-B fitted the second-order kinetic model very well with the rate constants(k2) of3.15 × 10-2, 3.84 × 10-2and 6.27 × 10-2g·mg-1·min-1, respectively. The adsorption process was not only controlled by intra-particle diffusion. The isotherms of MB on FFA-R, FFA-A and FFA-B can be described by the Langmuir isotherm and the Freundlich isotherm, and the adsorption processes were spontaneous and exothermic.