How to use the calorimeter

From the aspect of coal detection equipment, the use of microcomputer calorimetry equipment - the use of microcomputer automatic calorimeter has experienced the traditional Beckman temperature calorimeter, intelligent Chinese character semi-automatic calorimeter and automatic calorimeter 3 At the stage, the automatic calorimeter has been promoted in the coal inspection system, and has been continuously updated, which greatly improves the work efficiency and the accuracy of the test results.

The use of calorimeter to measure the calorific value of coal is a very important item for coal quality analysis. It is the main quality index of coal used for power. According to its calorific value, it can predict the degree of deterioration of coal and become an important parameter of coal classification index. The calorific value of coal has a significant contribution to coal production and sales.

1. Structure and working principle of calorimeter 1.1 Structure of calorimeter The calorimeter system consists of a printer, a computer, an inner cylinder, an oxygen bomb, a temperature sensor, an agitator, an ignition device, an outer cylinder, a temperature measurement and control system, and water. . The host of the microcomputer automatic calorimeter is generally composed of a casing, an inner cylinder, an outer cylinder, a stirrer, a backup water tank, a control circuit, a temperature sensor, an ignition electrode, a water circulation system, and the like.

Some microcomputer automatic calorimeters also have an external bobbin temperature control system and an external cylinder water temperature zone system that can keep the temperature of the entire calorimeter system and the external bobbin water temperature within a very small range.

1.2 Microcomputer automatic calorimeter working principle At present, the national production calorimeter is mostly thermostatic. The working principle is generally to put the oxygen bomb loaded with the coal sample and oxygenated to the specified pressure into the inner cylinder to start the water circulation, so that the water temperature is stable, then the water is injected into the inner cylinder, and after the predetermined amount of water is reached, stirring is started to balance the water temperature of the inner cylinder to At a certain temperature, the temperature probe detects the water temperature and records it in the computer. After the water temperature of the inner cylinder is stable, the control system indicates ignition ignition, and the coal sample rapidly burns under the combustion of oxygen. The heat generated is transmitted to the inner cylinder through the oxygen bomb, so that the inner cylinder temperature rises. When all the heat in the oxygen bomb is released, the temperature begins to drop. After the computer detects the drop in the water temperature of the inner cylinder, it is determined that the test of the sample is over. The system stops stirring and releases the inner cylinder water. The computer processes the result of the collected temperature data.

However, some microcomputer automatic calorimeters use pre-calibrated mathematical models to predict end-point temperatures based on temperature velocities over a period of time. Calculating the calorific value through data processing programs in software shortens the test cycle.

2, the use of automatic calorimeter 2,1 new microcomputer automatic calorimeter need to determine the thermal capacity of the effective working range of automatic calorimeter measurement speed and high degree of automation, but making the heat capacity of the calorimeter system may be with the temperature The change in the change, so you can not use the same heat capacity value in all cases. The effective working range of the heat capacity shall be determined according to the method specified in GB/T213-1996, and the actual heat capacity value to be used under different test temperature rise shall be determined.

2, 2 microcomputer automatic calorimeter under the following conditions must be re-calibrated heat capacity (1) replacement temperature control of the relevant authorities or temperature measurement card.

(2) Replace the calorimeter with larger components (such as stirrers, oxygen bombs).

(3) Valid for 3 months (automatic calorimeter validity should be appropriate).

(4) The calorimeter has been relatively moved.

(5) After replacing the external bobbin water.

(6) Calibrate the heat capacity, determine the calorific value and measure the calorific value.

(7) When checking the accuracy of the instrument with a reference material, if the difference between the measured value and the standard value exceeds the uncertainty range, or if the difference between the measured value and the standard value exceeds 50 J/G, the test value is not artificial or external. When caused.