Furnace controlled programmes

An independent furnace controller-programmer of a Du Pont 990 thermal analyzer. 

CO, reforming reaction was conducted at 500-750°C, reactants mole ratio of CH3 CO, He = 1 1 3, and space velocity = 20000-80000 1/kg/h. Methane oxidation was conducted at 150-550 °C using 1 % CH in air mixture (2 ml/min CH4 198 ml/min air) at space velocity = 60000 1/kg/h, and MIBK (4000 ppm in 150 ml/min air introduced by a syringe pump) combustion at 100-500°C and space velocity of 10000-30000 h 1. Catalytic reactions were conducted in a conventional flow reactor at atmospheric pressure. The catalyst sample, 0.1-0.3g was placed in the middle of a 0.5 inch I.D. quartz reactor and heated in a furnace controlled by a temperature programmer. Reaction products were analyzed by a gas chromatography (TCD/FID) equipped with Molecular Sieves 5A. Porapak Q, and 15m polar C BP 20 capillary column. 

Fig. 4.8.5. Schematic diagram of a DSC apparatus furnace (/), temperature programmer (2), temperature controller (2), amplifier (4), baseline controller (5), and recorder (6)...

A typical DTA apparatus is illustrated schematically in Figure 6.1. The apparatus generally consists of (1) a furnace or heating device, (2) a sample holder, (3) a low-level dc amplifier, (4) a differential temperature detector, (5) a furnace temperature programmer, (6) a recorder, and (7) control equipment for maintaining a suitable atmosphere in the furnace and sample holder. Many modifications have been made of this basic design, but ail instruments measure the differential temperature of the sample as a function of temperature or time (assuming that the temperature rise is linear with respect to time). 

A schematic diagram of the automated EGD apparatus is shown in Figure 8.31. Basically, the apparatus consists of a sample-changing mechanism and furnace, a programmer to control the rate of furnace temperature change, a thermistor thermal conductivity cell and bridge circuit, a two-channel strip-chart potentiometric recorder, and a helium supply and gas flowmeter. The electronic circuits for the sample changer mechanism were the same as previously described for the automated DTA apparatus (121). 

Figure 25.5 shows the flowchart of the experimental testing unit. It is used in a U -shaped quartz tube without bulb, the temperature is controlled by a thermocouple with a K-Type sensor associated to a controller/programmer and coupled to an electric resistance furnace. 

Description of a TGA Instrument. The components of the instrument are the microbalance, the furnace, the programmer controller, and a computer or data acquisition system. Topical arrangements of the components for TGA are shown in Figure 13. The sample can be linked to the balance in three different ways (i) above the balance, (2) below the balance, and (3) beside the balance as a horizontal extension to the beam. 

Figure 1. Schematic diagram of a Ihemiobalance a) Sample b) Sample temperature sensor c) Furnace temperature sensor d) Furnace e) Recorder or computer, logging sample mass, temperature, and time f) Balance controller g) Recording microbalance h) Gas i) Furnace temperature programmer...

The following programme is entered into the furnace controller (see also Table 12-3) ... 

As part of the quality control programme and to support accreditation according to the EN lEC/ISO 17025 2005 [6], each batch of samples should contain a reference material to validate the results. As there are currently no suitable and traceable certified reference materials available, several in-house reference materials (RMs) were developed. One iron ore and one sinter dust were selected to be developed as RMs for the alpha spectrometry method and the same sinter dust along with a blast furnace dust were selected for the gamma spectrometry method. When analysing stack emission samples, one blank filter was spiked with a known amount of a certified Pb standard solution (R22-02, National Physical Laboratory, UK) and used as a reference for result validation. 

The temperature control unit can be a simple furnace and programmer. The fact that in some cases the instrumentation operates a control of the furnace temperature, rather than the sample temperature, is an important design feature which has already been noted. The recording unit receives a signal from the measuring unit and the temperature thermocouple. In most cases this is fed into a dedicated computer, and this allows the signals to be displayed in a variety of different ways, depending on the requirements of the operator. 

In a DSC experiment the difference in energy input to a sample and a reference material is measured while the sample and reference are subjected to a controlled temperature program. DSC requires two cells equipped with thermocouples in addition to a programmable furnace, recorder, and gas controller. Automation is even more extensive than in TA due to the more complicated nature of the instrumentation and calculations. 

R. Linder, Programme-controlled reduction test for blast-furnace burdens, J.I.S.I., 189 (1958) 233-243. 

A modified Coleman Model 33 Carbon-Hydrogen Analyzer was used to control the oxygen flow rate, to pretreat the oxygen (anhydrous magnesium perchlorate and anhydrous lithium hydroxide) and to hold the combustion tube in position. The analyzers furnace was controlled by a Fisher Model 360 Linear Temperature Programme. The rate of temperature increase was variable from 0.5 to 25 C per minute. Normally, the temperature programmer... 

A flow scheme of a TPR instrument [2] is given in Fig. 11.2. The reactor containing the catalyst is situated in a furnace equipped with a temperature programmable controller. The effluent of the reactor is analyzed by one or more suitable detectors. A TCD is most commonly used for the detection of hydrogen... 

As shown in Fig. 4.8.1, a TG apparatus typically consists of a (1) recording balance, (2) furnace, (3) furnace temperature controller, (4) temperature programmer, (5) temperature detector, and (6) recorder. Most commercial models, e.g., Perkin-Elmer Model TGA-7, TA Instruments 2950 TGA, Mettler TC11ATG50, Seiko Instruments SSC 5200 TG-DTA 220, and Shimadzu TGA-50, consist of these basic components. 

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