Coal analysis instrument use method

The calorific value of coal refers to the amount of heat generated when a unit mass of coal is completely burned, which is mainly divided into high calorific value and low calorific value. The high calorific value of coal minus the heat of vaporization of water is the low calorific value. The international unit of calorific value is one million joules/kilogram (MJ/kg), and the common unit is kcal kilograms. The conversion relationship is: 1MJ/kg=239.14kcal/kg?1J=0.239gcal?1cal=4.l8J. Such as the amount of heat 550kcaL / g, 5500kcal/kg = 550 ÷ 239.14 = 23MJ / kg. For the convenience of comparison, the coal analysis method, when we measure the consumption of coal, the actual use of the different calorific coal should be converted into standard coal, The standard coal has a calorific value of 29.27 MJ/kg (700 okcal/kg). The standard for heat generation in domestic trade is the base heat value received (Qnet, ar). It reflects the application effect of coal, but external factors such as moisture, etc., so Qnet, ar can not reflect the true quality of coal. The universal heat output standard for international trade is the high-rate heat of air drying base (Qnet, ar). It can accurately reflect the true quality of coal and is not affected by external factors such as moisture. In the case of the same moisture, ash, etc., the air-based high base heat is about 1.25 MJ/g (300 kcal/kg) higher than the base heat level received.

The second index of coal analysis indicators: coal moisture determination. - Automatic Moisture Analyzer The coal analysis method is divided into intrinsic moisture, external moisture, crystallization water and decomposition water.

When the moisture in the coal is too large, it is not conducive to processing, transportation, etc., it will affect the thermal stability and heat conduction when burning, and it will reduce the coke yield and extend the coking cycle when coking.

Now we often talk about the water indicators are:

1. Total moisture (Mt) is the sum of all internal moisture and external moisture in coal. It is also commonly referred to as Mar. Usually set below 8%.

2. Air-dried base water (Mad) refers to the moisture content of coal in air-dry conditions. It can also be regarded as intrinsic moisture, and the old national standard calls it "analysis of basic water."

The third indicator of the coal analysis indicator: coal ash Aad-ash tester refers to the residue left by coal after burning.

Not the sum of minerals in coal, but the high ash content of these minerals after chemical and decomposing residues, indicating that the flammable content of coal is low. Heat is low.

At the same time, in the coking of refined coal, the ash content determines the ash content of coke.

The usual ash indicators are air dry base ash (Aad), dry base ash (Ad), etc. Also useful for receiving basic ash (Aar).

The fourth index of coal analysis indicators: Coal volatiles (full name volatile yield) (Vad) - Ash-fire tester refers to the organic decomposition of coal and some minerals, not all of the inherent components in coal, but also Some are pyrolysis products, so the volatile yield is called.

The amount of volatiles is related to the degree of coal metamorphism. The higher the degree of coal change, the lower the volatile yield.

In combustion, it is used to determine the boiler model; in coking, it is used to determine the proportion of coal blending; it is also an important indicator of vaporization and liquefaction.

Commonly used are air-dried base volatiles (Vad), dry-based volatiles (Vd), dry ash-free base volatiles (Vdaf), and receiving base volatiles (Var).

Among them, Vdaf is one of the important indicators for coal classification.

The fifth index of the coal analysis indicator: The fixed carbon-to-gray emission tester for coal is different from carbon for elemental analysis and is calculated based on moisture, ash, and volatiles.

FC AVM=100

The formula is as follows: FCad=100-Mad-Aad-Vad

FCd=100-Ad-Vd

FCdaf=100-Vdaf

The sixth index of coal analysis index: Total sulfur content of coal St-sulfur analyzer and sulfur analyzer are harmful elements in coal, including organic sulfur and inorganic sulfur. Less than 1% can be used for fuel. Some areas require below 0.6 and 0.8. Nowadays, environmental protection coal and green energy all refer to coal with low sulfur content.

Commonly used indicators in coal analysis methods are: air-dried total sulfur (St, ad), dry-based total sulfur (St.d), and received-based total sulfur (St, ar).