DTA-EGD-GC on-line coupled simultaneous technique

The functioning of the DTA-EGD-GC on-line coupled simultaneous apparatus is as follows  

The EGD curve traces the variation in the DTA curve and the features of the thermal variations of DTA can be directly revealed, whether it is due to a physical process or a chemical reaction. 

According to the variations in the DTA-EGD curves, the relevant component of the reaction gases evolved at any temperature can be intercepted intermittently and analyzed by GC using a sampling valve at different time intervals. 

The information and data from four aspects of DTA-EGD-GC and T (temperature of reaction and thermal effects, etc.) can be obtained by one measurement from a single sample at the milligram level under the same conditions. 

---

Evaluation of Catalysts in the Solid State by the DTA-EGD-GC On-line Coupled Simultaneous Technique... 

DTA-EGD-GC on-line coupled simultaneous technique and relevant equipment (see section 2.4) arc effective tools for evaluating catalysts [14-17],... 

The DTA-EGD-GC on-line coupled simultaneous technique provides a microscale experimental method that is precise and rapid for the investigation of the reaction processes involved in the thermal decomposition of samples. The variations of the composition of reaction gases evolved can be traced and the mechanism of gas-solid phase and gas-gas phase thermal reactions in an inert gas or reactant gas can be studied. 

For extended applications, a DTA/DSC-EGD-GC on-line coupled simultaneous technique and relevant apparatus were established in the 1980s [63]. The CDR-1 E>SC analyzer was replaced by the Model CRY-1 DTA (ambient temperature ca 1200 C) for the purpose of high-temperature measurements. The scheme of the DTA-EGD-GC on-line coupled simultaneous apparatus is shown in Figure 2.37. DTA and a EGD-GC... 

An analytical scheme for the TA-EGD-EGA coupled simultaneous technique is shown in Figure 2.32. The evolved gas from TA (DTA/DSC or TG) is introduced into the EGA system after passing through the EGD system. The evolved gas is directly introduced to a thermal conductivity detector (TCD), avoiding second reactions. Two methods are used for the TA and EGA coupled simultaneous technique (1) on-line coupled simultaneous technique in series and (2) off-line combined method. In technique (1), TA is connected serially with a Gas chromatograph (GC) [61-65], mass spectrometer (MS) [57, 64, 65], Fourier transform infrared (FTIR) spectrometer [66, 67], non-dispersive IR (NDIR) spectrometer [68, 69] or thermo-gas-titrimetric... 

The DTA/DSC-EGD coupled simultaneous technique and relevant equipment have been investigated since 1979 [62, 74, 75]. The Model CDR-1 power compensation DSC analyzer (ambient temperature ca 720 C) was developed by the Tian Ping Instrumental Factory (Shanghai, China). The EGD detector is a thermal conductivity detector (TCD) in the GC analyzer. The CDR-1 DSC analyzer coupled with GC was constructed using a specially designed gas conduit. A schematic diagram of the on-line coupled simultaneous DTA/DSC-EGD apparatus is shown in Figure 2.33. 

---