Showing papers on "Charring published in 2005"

Structural fire design according to Eurocode 5 - design rules and their background

Abstract: This paper gives a review of the design rules of EN 1995-1-2, the future common code of practice for the fire design of timber structures in the Member States of the EU and EFTA, and makes reference to relevant research background. Compared with the European pre-standard ENV 1995-1-2, the new EN 1995-1-2 has undergone considerable changes. Charring is dealt with in a more systematic way and different stages of protection and charring rates are applied. For the determination of cross-sectional strength and stiffness properties, two alternative rules are given, either by implicitly taking into account their reduction due to elevated temperature by reducing the residual cross-section by a zero-strength zone, or by calculating modification factors for strength and stiffness parameters. Design rules for charring and modification factors are also given for timber frame members of wall and floor assemblies with cavities filled with insulation. A modified components additive method has been included for the verification of the separating function. The design rules for connections have been systemized by introducing simple relationships between the load-bearing capacity (mechanical resistance) and time. The code provides for advanced calculation methods for thermal and structural analysis by giving thermal and thermo-mechanical properties for FE analyses. The code also gives some limited design rules for natural fire scenarios using parametric fire curves.

Experimental study on the concept of liquid cooling for improving fire resistance of FRP structures for construction

Abstract: This paper presents experimental studies on the fire behavior of fiber reinforced polymer (FRP) composite laminates and unloaded cellular FRP components with internal liquid cooling. The experiments were conducted to verify the objective of liquid cooling for improving the fire resistance of FRP composite structures for construction applications. Observations show that the pultruded E-glass/polyester composites are vulnerable under ISO-834 fire conditions, and the fire-resistance effect of charring of the resin is insignificant. Liquid cooling is demonstrated to be an efficient way to improve fire- resistance of FRP cellular construction components. With liquid cooling, cellular FRP profiles can satisfy the code requiring 90min fire resistant design time for building constructions. The cooling effect improves with increased liquid flow rates. In practice, low to moderate flowing rates (0.2-1.0cm/s) will be sufficient for improving fire resistance of FRP structures and, at the same time, can serve to heat and cool a building. [All rights reserved Elsevier]

Method for preparing stalk charcoal and stalk vinegar liquid form stalks of cropper

Abstract: A method for preparing straw charcoal and straw vinegar liquid includes placing agricultural straw into retort for pyrolytic reaction of 4-12 h. at 300-600 deg.C under condition of oxygen being isolated or being provided with limitation; obtaining straw charcoal from solids through drying, precharring, charring and calcining; obtaining straw vinegar liquid and combustible gas by arrying out gas-liquid separation of pyrolysis gas and sending combustible gas back to combustion chamber as heating source.

Extension and evaluation of the integral model for transient pyrolysis of charring materials

Abstract: In most numerical simulations of fire growth and fire spread, pyrolysis models are required to calculate the reaction of the solid material to an incident heat flux. Important results of the pyrolysis model are the mass release rate of combustible pyrolysis gases and the surface temperature. In this paper an integral model is evaluated for the prediction of pyrolysis of charring materials. An existing integral model is extended with a finite and semi-infinite cooling state. In this state both char and virgin material are present but the pyrolysis reactions have been interrupted due to insufficient heat supply. The results show that such a cooling state can occur in flame spread calculations. Simulations with the integral model are further compared with the results of a moving grid model, which has the same physical basis. Unlike the integral model, the moving grid model does not require any assumption for the temperature profile in the solid. The influence of the quadratic assumed temperature profile in the integral model on the accuracy of the predictions of the mass release rate of pyrolysis gases is evaluated for several cases. It is shown that the integral model has problems with sudden variations of the external heat flux. Copyright © 2005 John Wiley & Sons, Ltd.

Method for producing charcoal by using agricultural and forest waste

Abstract: The invention discloses a method for preparing mechanism charcoal by employing agroforestrial solid waste. The method comprises employing the disintegrated agroforestrial solid waste as stock, mixing it with wood tar according to the mass ratio 2~5:1, extrusion molding, feeding the retort with formed stick for charring reaction, which comprises three parts, (1) heating-up to 120 DEG C for 10-20 minutes; (2) heating-up to 120-350 DEG C for 220-240 minutes; (3) heating-up to 350-450 DEG C for 130-220 minutes; getting charcoal after the charring. The exhaust gas generated in retort is introduced to burner for burning, which offer heat source for heating-up in the retort. The productivity is 40-46%, the energy consumption is low and there is little pollution.

Method for preparing carbon gas gel

Abstract: A process for preparing the organic aerogel and its carbon aerogel includes such steps as reaction between resorcin, formaldehyde, organic surfactant and catalyst in water, thermal solidifying to obtain organic gel, natural cooling or baking to obtain organic aerogel, and charring in inertial gas to obtain carbon aerogel.

An Investigation of the Effects of Zeolites on the Thermal Degradation and Charring of APP–PER by TGA–XPS

Abstract: The effects of zeolites 4A, 13X, mordenite, and ZSM-5 on the thermal degradation and charring of intumescent ammonium polyphosphate (APP)–pentaerythritol (PER) systems were explored by X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analyses (TGA). The weight loss rate of the third main degradation step (corresponding to the maximum degradation rate of APP–PER) was remarkably decreased for all systems with addition of zeolites, especially for the systems with 4A and 13X where the minimal weight loss rate, 0.13%/ C and 0.11%/ C, were found. The residues of APP–PER systems with 4A and 13X at 600 C were 33–35% higher than that of the pure APP–PER system. The XPS–TGA results indicated that zeolites might execute their effects on the thermal degradation of APP–PER by two ways, that is, by catalyzing the esterification reaction between APP and PER at temperatures below 250 C and enhancing the cross-linking and charring by SiO2 and Al2O3 produced by the breakage of zeolites at temperatures above 2...

Design of Ablative Liners for High Heat and Erosive Conditions

Abstract: This paper presents an analytical approach to predict the thermal response of charring and noncharring ablative liners exposed to high heat and erosive conditions. A one-dimensional transient thermal model has been developed, which forms the basis of a computer code to predict the temperature distribution in the liner, the amount of char and erosion, and the liner thickness required to satisfy a given design criterion. The accuracy of the model was evaluated by comparing the predicted and the experimental results available for the carbon-phenolic and the graphite liners, which showed a good agreement to each other.

Method for increasing tar yield of coalite pyrolysis with methane as reaction gas

Abstract: The invention belongs to energy technology field and provides a method for increasing coking yield in coal pyrolytic and coking process. The method comprises employing methane as reacting gas and adding adequate oxidant, mixing them and introducing them to the pyrolytic reactor, which comprises two layers, the middle layer is separated by gas grid plate, activating the methane by catalyst, and introducing it to the coal layer, pyrolising and charring the coal. The invention is characterized in that it employs the methane instead of pure hydrogen gas as reacting gas, which can deduce the pyrolising cost; the coking yield is higher than that of employing hydrogen gas in the same condition; the char coal yield is equal to that of in the inert atmosphere but higher than that of employing hydrogen gas; the catalyst and coal do not mix directly, which is suitable for recovering.

Method for preparing high hear conduction intermediate phase asphalt base charcoal materials

Abstract: A method for preparing high heat conducting interphase bitumen material, uses band-shaped interphase bitumen fiber which is not melton in 180-280deg.C, with the speed to increase temperature being 0-150deg.c im 1-5deg.C/min, 150deg.C the final temperature being 0.2-0.6deg.C/min, and be dept in the final temperature for 1-3h, then be stamped to form the product in the pressure of 20-100MPa and temperature of 200-300deg.C, through charring and graphitization to generate the high heat conducting material. The invention has simple technique, avoids interference of filler or sticker and can be made into high heat conducting carbon material directly.

Method for producing form coke from Jurassic steam coal

Abstract: Method for producing form coke from Jurassic steam coal comprising the steps of, coal disintegrating, washing, drying, dry distillation so as to obtain high temperature coal tar and half-tar or refined gluing coal, disintegrating to below 0.4mm, obtaining powdered coal binding agent, distilling into pitch binding agent, preparing shaped coal by mixing 8-15% of pitch binding agent, 15-25% of powdered coal binding agent, charring the molded coal to obtain molded coke.

Process for heat maintaining whole walls of coke carbonating chamber

Abstract: A new thermo repairing process is used for whole wall of coke-oven charring house. It is carried out by: supporting the wall and retaining the temperature of the wall neighboring the coke-oven charring house, repairing the whole wall and replacing the oblique canal of charring house, making sure the new wall smooth, no expansion and depression when the temperature is increasing, making damages of neighboring wall at a low level. The mended wall is smooth and vertical. The width of charring house is uniformly. Taper and height are acceptable. The effect is good in experiment.

Method for producing biomass charcoal and charring furnace with double furnace chambers therefor

Abstract: The invention includes a method to produce biological carbon and its double-furnate charring furnace. The method is: shatter, filter, dry and place the materials meeting the requirements in to cavity of charring furnace separately, ignite the material in cavity of gasification furnace to make gasification, putout the biological carbon dry distilled and charred in the cavity of charring furnace through the outlet for product. The main structure of double-farnace charring furnace includes there are mouth of pipe in the middle of upper furnace, and cavity of gasification furnace and cavity of charring furnace in the furnace. Its has biological fuel gas with hest value of 800-1000kg/m3, can be reused, after being scatter and add into watersoluble high molecular sticker, is useful to prolong the time of exhaustion of delay the fossil fuel resure; it makes good use of waste in farming and forestry, saves energy, has simple and reasonable structure of double-furnace charring furnace, convenient operation and large quality of processing material, high speed and efficiency of caring in furnace.

Heat transfer room type heat recovery coke-oven

Abstract: The invention discloses a novel cell-type coking furnace, wherein the coal is subjected to destructive distillation in charring chamber, most of the obtained coal gas enters horizontal gas channel, and is divided to adjacent blast chambers through the coal gas distribution hole, the rest is distributed to each blast chamber. The dedusted thermal waste gas can be used by exhaust-heat boiler to produce steam power generation.

Method for preparing natural graphite cathode material of lithium ion battery

Abstract: The invention discloses a making method for lithium ion battery negative materials, comprising the steps of: (1) mixing the black lead, clad material and solvent, evacuating, stripping solvent and cladding the natural black lead in the clad materials; (2) polymerizing the materials and the surface of the natural black lead will get the microencapsulation cladding layer; (3) charring or charring the products of step (2) to get the carbon negative materials with the artificial black lead layer coated on the surface, this is the lithium ion battery negative materials. The detecting results of the battery negative materials are: tap density is more than 1.08, specific surface area is lese than 2.20, the first discharging capacity is more than 350mAh/g (non-reversible capacity is less than 25mAh/g), the first charging efficiency is more than 93%, after circulating 450 times, the rest first capacity is more than 90%.

Process for preparing foundry coke

Abstract: The invention discloses a method for preparing foundry coke, employing blind coal as stock, disintegrating it separately into three grade size: 1~3mm, 0.18~1mm, u“0.18mm, for reservation. Adding coal pitch and coal tar as adhensive, filling the mixing and kneading pot with the said three blind coal, stirring at the temperature 110~130 DEG C for 10 minutes, adding the fused coal pitch and coal tar into the mixing and kneading pot, stirring for 10 minutes. Employing pair roller forming or press forming to the mixed and kneaded sample for forming, then setting for 24 hours, for reservation. Feeding the retort with formed sample for warming-up and charring, covering the surface of the sample with pulverized coke for air insulation and avoiding oxidization; cooling in natural way after charring to normal temperature, removing the pulverized coke, fetching it out and getting the needed product.

Press block unshaped breaking active carbon and producing method thereof

Abstract: An activated carbon is prepared from low-viscosity coal, charred coal and coal asphalt asphalt through breaking, grinding, die pressing to become blocks, crushing to become particles, charring, and activating in Slep furnace.

Chinese chestnut bract shell solid shape carbon and its manufacturing method

Abstract: A solid charcoal is prepared from the soft and hard shells of chestnut through pulverizing, drying die pressing and charring. Its advantages are high heat value and no pollution.

A Partial Differential Model for the Pyrolysis of Materials with Movable Residual Layer

Abstract: Due to the existence of nonlinear mobile boundary conditions in the pyrolysis process of charring materials, such as the insulating layers of wires and cables, the precise tracing of the pyrolysis surface and calculating the pyrolysis rate pose a great challenge for researchers when trying to model the process using partial differential models. In this paper, the direct numerical simulation method including a set of partial differential equations has been exerted to make detailed studies on the pyrolysis of materials with changeable residual layers. In the simulation, a movable domain model was transformed to a fixed domain model and a cyclic iterative method was adopted to predict the thermal interface location between pyrolysis zone and virgin material. Resulting numerical results show good correlations with the exact solutions and the results of an integral model. In addition, influences of the residue mass ratio of the charring layer on the evolution of pyrolysis rate of the polyethene materi...

Method and device for dry distillation and charring of internal combustion self-heating moving bed

Abstract: Disclosed is a wood (bamboo) moving bed consecution dry distillation charring process and a corresponding internal combustion self-heating moving bed consecution dry distillation retort, wherein the raw material, the gas and steam produced by dry distillation are in counter-current flow in the bed layers, the lower portion of the furnace is provided by at least four air intakes for leading-in air in a controlled manner, the combustible constituent produced in the combustion charring process can calcinate the wood (bamboo) charcoal at the temperature of 601-800 deg. C, the blanking tube is made of material with good thermal conductivity, the incinerated wood (bamboo) charcoal can be cooled to room temperature and discharged through the blanking tube.

Fire behaviour of timber surfaces with perforations

Abstract: Timber surfaces with perforations are unfavourable from a fire design point of view, since the perforations increase the surface area exposed to fire and facilitate an increased penetration of heat into the burning 49 zone. This can lead to an increased burning rate in comparison with heavy timber surfaces. In order to enlarge the theoretical and experimental background of the fire behaviour of timber surfaces with perforations, a series of fire tests was performed on timber assemblies made of hollow core elements with acoustic perforations and sound absorbers placed behind the perforated acoustic layer. This type of element is commonly used to improve ceiling sound absorption. The first part of the paper describes the results of the fire tests, in the second part a simplified calculation model for the burning rate is presented and compared with the test results. The model takes into account two different charring phases, before and after the perforated acoustic layer is completely charred. Good agreement between the test results and prediction of the calculation model is observed. Further the fire tests clearlv showed that the charring rate during the first phase is mainly influenced by the size and the position of the perforations as well as the thickness of the perforated acoustic layer. A correlation between the charring rate and these parameters is also presented and compared with the test results.

Preparation process of porous phenolic resin group charring microball

Abstract: The invention discloses a mulitporous phenolics based carbon mcirosphere preparing method, including the following steps: mixing the alcohol solution of resol with the water solution of surfactant to form a uniform emulsion, stirring and solidifying at temperature of 100 deg.C-50 deg.C, then heating to 800 deg.C-1200 deg.C at a temperature ascending speed of 5 deg.C-10 deg.C/min, keeping constant temperature for 0.5-1 hour and carbonizing, and cooling to obtain the phenolics-based carbon mcirospheres. It has cheap raw materials, simple technique, high yield, good sphericity, controllable sphere diameter and specific surface area.

In Situ High-Temperature EPR Investigation of the Charring of Tobacco and the O2-Induced and H2O-Induced Behavior of the Char

Abstract: In situ high-temperature EPR has been used to study the 350 and 500 °C pyrolysis (under a He atmosphere) of tobacco, as well as the EPR-signaled changes in the resulting char under exposure to O 2 and H 2 O after quenching to room temperature. Exposure of a char to O 2 leads to a large increase in free radical concentration, especially for the 350 °C char. Exposure of the char to both O 2 and H 2 O yields an additional increase in free radical content (followed by a decrease after a maximum is reached), the magnitude of this increase being roughly half that of the initial O 2 -generated increase. The observed patterns result from a complicated chemical interplay involving the creation and destruction of carbon-centered and oxygen-centered free radicals.