2223 results about "Pulverized fuel ash" patented technology

A method of treating a coal combustion flue gas, which includes injecting a molecular halogen or thermolabile molecular halogen precursor, such as calcium hypochlorite, able to decompose to form molecular halogen at flue gas temperature. The molecular halogen converts elemental mercury to mercuric halide, which is adsorbable by alkaline solids such as subbituminous or lignite coal ash, alkali fused bituminous coal ash, and dry flue gas desulphurization solids, capturable in whole or part by electrostatic precipitators (ESPs), baghouses (BHs), and fabric filters (FFs), with or without subsequent adsorption by a liquid such as a flue gas desulphurization scrubbing liquor.

A synthetic slag is produced by a high temperature combustion reaction between coal ash having a high carbon content, and a source of lime such as cement kiln dust. The carbon content of the coal ash is oxidized by oxygen gas, which typically is derived from air or an air / oxygen combination in an exothermic reaction and the heat generated is exploited in the melting process. In this way the gaseous products will typically comprise nitrogen, unreacted oxygen and carbon dioxide, and heat energy can be readily recovered from the hot off gas products evolving during the combustion reaction. The synthetic slag may be pelletized and employed as lightweight mineral aggregate or milled to cement fineness to provide slag cement.

Sorbent components containing calcium, alumina, silica, and halogen are used in combination during coal combustion to produce environmental benefits. Sorbents are added to the coal ahead of combustion and / or are added into the flame or downstream of the flame, preferably at minimum temperatures to assure complete formation of the refractory structures that result in various advantages of the methods. When used together, the components ● reduce emissions of mercury and sulfur; ● reduce emissions of elemental and oxidized mercury; ● increase the efficiency of the coal burning process through de-slagging of boiler tubes; ● increase the level of Hg, As, Pb, and / or Cl in the coal ash; ● decrease the levels of leachable heavy metals (such as Hg) in the ash, preferably to levels below the detectable limits; and ● make a highly cementitious ash product.

A rapid hardening hydraulic cement is provided that is made substantially exclusively from a subbituminous fly ash with no portland cement or other strengthening aid.

Methods by which new or used boilers or furnaces ranging from small industrial to the largest utility units that are designed for coal or oil or natural gas or shredded waste or shredded biomass firing can substantially improve their technical operation and sharply reduce their capital and operating costs by implementing component modifications and process steps that (a) minimize the adverse impacts of coal ash and slag on boiler surfaces and particulate emissions thereby also facilitating the use of oil or gas designed boilers for coal firing, (b) drastically reduce the loss of water used to transport coal in slurry form to power plants, (c) essentially eliminate the combined total nitrogen oxides (NOx), sulfur dioxide (SO2), mercury (Hg), trace metals, and carbon dioxide (CO2) emissions, (d) separate and permanently sequester carbon dioxide released during combustion and (e) improve the coal and solid fuel combustion efficiency.

The invention relates to a small soilless culture method and device. A nutrient solution is contained in a culture disk or a nutrient solution storage pool; crops are planted into the nutrient solution; a soil copy material is added into the nutrient solution; the soil copy material comprises the following raw materials in parts by weight: 20-90 parts of organic matter and 2-80 parts of nonmetal mineral substance, wherein the organic matter is one or mixture of peat, fermented straw, fermented bagasse and fermented livestock and poultry manure; the nonmetal mineral substance is one or mixtureof coal ash, steel slag, zeolite, bentonite, opal, attapulgite mineral soil, pearlite, vermiculite, rectorite clay, sepiolite clay and kieselguhr; and the proportion of the nutrient solution to the soil copy material is (5-2):1. By adding the soil copy material into the nutrient solution, the nutrient charge concentration can be improved, the nutrient charge frequency is reduced, and the labor cost is reduced; meanwhile, when the concentration is reduced due to the absorption of the nutrients, the concentration reduction range is slower, and a deficiency symptom caused by lacking nutrients ofplants is lightened; in addition, trace elements needed by plants can be also supplemented.

The invention relates to the environmental protection field of flue gas treatment of gas-fired boilers, in particular to a surface deposition honeycomb flue gas denitration catalyst and a preparation method thereof. The catalyst comprises a honeycomb framework which takes clay, soot dust or slag as a substrate; TiO2 is taken as an active carrier; WO3 and V2O5 serving as active ingredients are loaded on the TiO2 active carrier, and are uniformly distributed in the honeycomb framework; and the catalyst comprises the following components in percentage by weight: 60-80 percent of clay, soot dust or slag, 13-33 percent of TiO2, 1-5 percent of WO3 and 0.1-2 percent of V2O5. By transferring an ignition lost transition carrier, highly dispersion of catalyst nanoparticles on a molding catalyst pore cannel and an outer surface is realized, and the utilization ratio and catalytic activity of the active ingredients are increased greatly.

The invention provides an autoclaved aerated concrete brick prepared by utilizing pulverized fuel ash and a preparation method thereof. The brick is prepared from the following materials by weight percent: 65%-68% of pulverized fuel ash, 17%-23% of lime, 6%-10% of cement, 2%-4% of desulfurization gypsum, 1%-1.5% of water-soluble aluminum powder, 0.5% of fatty acid soap and 0.5% of gleditsia sinensis powder. The preparation method comprises steps of: adding water to pulverized fuel ash and desulfurization gypsum which are screened mechanically and grinding together to form slurry, wherein the fineness of the pulverized fuel ash has to reach the condition that the residual of a 0.08mm square hoe sieve is not more than 15%; carrying out stirring, pouring, cutting and thermal, static and suspension curing on the slurry together with the lime, the cement and the aluminum powder suspension liquid which are weighed according to a weight ratio of a formula; utilizing an autoclave with good sealing for heating with 180-200 DEG C saturated steam under proper pressure (1.0-1.2Mpa); and steam curing for 8-10 hours so as to produce the aerated concrete brick. The aerated concrete brick has the characteristics of light weight, high strength, good heat insulation performance, good fire resistance and sound absorption, labor saving and energy saving, waste recycling and the like; and the aerated concrete brick meets constructional engineering requirements and environment protection requirements, and the wastes of enterprises are reasonably used.

The invention relates to a polyvinyl alcohol fiber reinforced cement-based material composition, and a preparation method and application thereof, belonging to the technical field of building materials, wherein the polyvinyl alcohol fiber reinforced cement-based material composition is prepared by mixing polyvinyl alcohol fibers with a cement-based material. The polyvinyl alcohol fiber reinforced cement-based material composition is characterized in that: (1) the cement-based material is prepared from the following raw materials in parts by weight: 1000 parts of sand, 260 to 400 parts of cement, 300 to 350 parts of pulverized fuel ash, 25 to 30 parts of silicon ash, 0 to 120 parts of levigated quartz powder, 5 to 10 parts of high-efficiency water reducing agents and 300 to 350 parts of water; (2) the mixing quantity of the polyvinyl alcohol fibers is 0.75% to 1.5% of the total weight of a gelled material. The polyvinyl alcohol fiber reinforced cement-based material composition has the advantages of high crack resistance, high durability, easy acquirement of the raw materials, simple fabrication and low cost, can be extensively applied to the building materials, in particular to cement-based boards, building tiles, cement posts and the like.

The invention relates to a contaminated soil passivator and a preparation method and application thereof. The passivator is formed by mixing the following raw materials in percentage by weight: 30-60 percent of a natural clay mineral material, 30-60 percent of industrial harmless wastes and 10-20 percent of a cation-exchanger, wherein the cation-exchanger refers to an X-type molecular sieve or a molecular sieve with the particle size of more than 4A. Compared with the prior art, the passivator disclosed by the invention is completely prepared from the natural clay mineral material and a mineral-like material, the cost is low, secondary pollution is avoided, the environment friendliness idea is completely achieved, the pulverized fuel ash and other industrial wastes are introduced, the problems such as waste storage and treatment are solved, and the passivator has good passivation effect and high long-term stability on the contaminated soil, particularly heavy metal contaminated soil, and is suitable for large-scale popularization and application.