Pyrolysis tube furnace

On the basis of the data obtained from the early thermal analysis and tube furnace pyrolysis experiments performed during the initial phases of this investigation, it became apparent that in order to establish the principal reaction pathways to the generation of volatile antimony species, the volatile degradation products of the DBDPO itself would need to be characterized (24, 25). 

Controlled furnace-type pyrolyser a, heater b, A1 block c, variable transformer d, gas outlet to column e, Swagelok union f, column oven g, gas inlet h, cement i, glass wool plug j, insulating block k, pyrometer 1, stainless steel chamber m, sample n, heater thermocouple o, pyrolysis tube p, ceramic tube q, line voltage. 

Apparatus. Pyrolysis experiments were conducted in a quartz tube heated by an induction furnace. A continuous flow of argon was used to sweep out gaseous pyrolysis products. The materials to be pyrolyzed were contained in alundum boats, which could be readily admitted and removed from the quartz pyrolysis tube. 

The checkers used a Hoskins tube furnace, type FD303A (Central Scientific Co.), 17 in. long. The heater for the sublimation vessel was wound in two sections with heating wire in such a way that a decreasing temperature gradient in the direction of the pyrolysis oven was maintained. The open end of the heater was closed by an asbestos end plate which could be heated independently by a small nichrome coil. 

NFX 70-100 Analysis of pyrolysis and combustion gases. Tube furnace method. Part 1, Methods of analysis of gas generated by thermal degradation. Part 2, Method of thermal degradation using tube furnace. 

Apparatus Use the Dohrmann Microcoulometric Titrating System (MCTS-30), or equivalent (shown in Fig. 30), unless otherwise specified in an individual monograph. It consists of a constant rate injector, A, a pyrolysis furnace, B, a quartz pyrolysis tube, C, a granular-tin scrubber, D, a titration cell, E, and a microcoulometer with a digital readout, F. 

Sampling Syringe A microlitre syringe of 10-p.L capacity capable of accurately delivering 1 to 10 p,L of sample into the pyrolysis tube. Three-inch x 24-gauge needles are recommended to reach the inlet zone of the pyroloysis furnace. 

Pyrolysis furnaces are designed to proride a rapid lerr.peraturc rise of the feedstock, a hi exit temperature, and very short residence time, in solving these problems, the design of the pyrolysis tubes and furnaces are of decisive importance. 

In ideal conditions, a furnace operatmg on naphtha can run for 90 days without decoking. However, the run length is always shorter due to the inevitable fouling of the quench boiler. Progressive coke deposition in the pyrolysis tubes results in an increase in their metal skin temperature, connected with the growing ineffldency of heat transfer, and in an increase in the pressure drop caused by the redaction of the open cross section of the tube. 

Ethane enters the pyrolysis section, which comprises a series of cracking furnaces. The ethane is heated as quickly as possible to the cracking temperature and maintained at this temperature for the minimum residence time. In order to lower the hydrocarbon partial pressure and mitigate coke forming in the pyrolysis tubes, steam is added to the ethane prior to entering the pyrolysis section (not shown). 

Pyrolysis Equipment and Procedure. The decant oil samples were pyrolyzed using a horizontal tube furnace equipped with an electronic temperature controller. The samples (1-2 g) were weighed into stainless steel tubes (6 mm o.d., 200 mm long), which were then flushed with nitrogen and sealed with Swagelok end caps. It was important that the sample holder be capable of complete disassembly to facilitate the recovery of the products of pyrolysis, which were largely viscous tars and coke. It had been found previously with a more elaborate flowthrough reactor system, that not all the carbonaceous reaction products could be recovered readily. 

The conversion of appropriate precursors to condensed PAHs at elevated temperatures is the classical synthesis of numerous pure aromatic compounds. Depending on the reactivity of the starting materials temperatures between 300°C and 1300°C have been applied [31]. The reactions are normally performed in an inert quartz tube placed in a furnace with resistance heating (see Scheme 1). The precursor is transferred into the gas phase in a temperature controlled evaporation zone and swept through the pyrolysis tube by a carrier gas and/or a pressure gradient produced by a vacuum pump. The process has been referred to as flash vacuum pyrolysis (FVP) with typical reaction times of 2 -50 ms or as flow pyrolysis (FP, typical reaction times 0.2-2 s) if the conversion is carried out under normal pressure. The pyrolysis products condense immediately behind the oven in a cold trap. 

Pyrolysers with a pyrolysis chamber of the tube-furnace type whose walls are heated to the pyrolysis temperature. 

In a tube furnace Extensive application, including analysis of insoluble, infusible and fibrous samples. Broad temperature range. The sample size does not change within a broad range. Low cost Relatively large dead volume. The pyrolysis time is not controllable. The temperature remains invariable throughout the experiment (the sample is pyrolysed only at one particular temperature). Relatively broad initial volatile product zone... 

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