GB/T 4000-2017Determination of coke reactivity index (CRI) and coke strength after reaction (CSR) (English PDF)

4.1 Electric furnace

Electric furnaces may be heated by electric furnace wire, silicon carbide or other heating elements that can meet the test requirements.

4.2 Temperature-control device

4.2.1 Temperature-control requirements

The temperature-control device can display the upper, middle, lower temperature of the specimen layer in real-time under the test state, ensure that when the carbon dioxide reacts with the coke specimen, the temperature of the gas entering the specimen layer as well as the temperature of the entire specimen layer can be stabilized within the range of (1100 ± 3) °C.

4.2.2 Temperature-controller

4.2.3 Three-point thermocouple (see Figure 2 for schematic diagram)

Type-S, not lower than industrial grade-II, the thermocouple's measurement ends are located in the upper, middle, lower parts of the center of the specimen, respectively.

4.3 Reactor (as shown in Figure 3)

4.3.1 Reaction tube's material. GH3044

4.3.2 Reaction tube's wall-thickness. >= 1.5 mm

4.4 Type-I drum (see Figure 4 for schematic diagram)

4.4.1 Constant rotation speed. 20 r/min

4.4.2 Drum. It is made of seamless-steel tube which has an inner diameter of 130 mm and thickness of 5 mm ~ 6 mm. The net length inside the drum is 700 mm ± 1 mm, the thickness of the drum's cover is 5 mm ~ 6 mm.

4.5 Carbon dioxide supply system

4.5.1 Carbon dioxide. purity >= 99.5%, dry, where the concentration of O2 shall be < 0.01%.

4.5.2 Carbon dioxide's mass-flow controller. the range is 5 L/min, the accuracy is not less than ±1.5% F.S.

4.6 Nitrogen supply system

4.6.1 Pure nitrogen. purity >= 99.99%, dry

4.6.2 Nitrogen's mass-flow controller. the range is 5 L/min, the accuracy is not less than ±1.5% F.S.

4.6.3 The air inlet of the equipment is equipped with the nitrogen pressure-reducing valve.

6.1 Number of tests

Perform at least two tests. Record the quantity of coke particles per test, ensure that the difference between the quantity of coke particles used in the repeatability test and the reproducibility test is not more than one. If it cannot guarantee meeting the requirements for the quantity of coke particles, indicate it in the report and state the causes.

6.4 Temperature-rise

The electric furnace is heated up, at a heating rate of 8 °C/min ~ 16 °C/min.

When the temperature of the material layer reaches 400 °C, lead in nitrogen at a flow rate of 0.8 L/min, to prevent the burn loss of coke. When the temperature of the material layer reaches 1050 °C, preheat the outlet of the carbon dioxide cylinder, to ensure stable outflow of carbon dioxide.

6.5 Cooling of specimen

Remove the reactor, reduce the temperature to below 100 ° C under nitrogen protection, stop leading in nitrogen.

6.6 Weighing

Open the reactor, pour off the coke, weigh it, accurate to 0.1 g, record it as m1. Meanwhile record the quantity of particles of specimen after reaction.

7.1 Coke reactivity index

Coke reactivity index (CRI) is calculated according to formula (1), the value is expressed in %.