A method for determining different forms of moisture in sludge by headspace gas chromatography

Abstract

The invention discloses a method for measuring different forms of moisture in sludge by headspace gas chromatography, which comprises: (1) placing the sludge in a headspace bottle, and after sealing, balancing in the headspace bottle; (2) placing the sludge in a headspace bottle; The obtained sample is put into the headspace gas chromatograph, and after balancing in the headspace sampler, it is detected by gas chromatography to record the gas phase signal value A of water; (3) after repeated extractions, the gas phase signal value is compared Number logA and the number of extractions n draw a graph, and the obtained logA constant speed zone is free water evaporation; the first linear decline zone of logA is capillary water evaporation; the second linear decline zone is surface bound water evaporation; (4) According to the established standard Curve to calculate the mass of each part of the water; measure the water content of the sludge to obtain the total water mass of the sludge, and subtract the previously measured water mass of the three different forms to obtain the combined water mass of the sludge. The invention can efficiently and accurately measure the distribution of different forms of water in the sludge.

Description

technical field [0001] The invention relates to the field of measurement of different water form characteristics of sludge. Specifically, the present invention relates to a method for measuring different forms of moisture in sludge by headspace gas chromatography. Background technique [0002] With the enhancement of people's awareness of environmental protection and the increasingly stringent requirements of the government for environmental protection, the treatment rate and degree of sewage treatment continue to increase, followed by a sharp increase in the output of sludge, the residual sediment after sewage treatment. The moisture content of sludge is generally as high as 95%-99%, which brings a lot of inconvenience to transportation and subsequent disposal. Therefore, reducing the moisture content of sludge to achieve sludge reduction is an indispensable link in sludge treatment and disposal. [0003] The composition of sludge is complex and the content of organic mat...

AI Technical Summary

Problems solved by technology

At present, pressure filtration, centrifugation, differential scanning calorimetry, and dilatometric methods have all been used to analyze the water distribution of sludge, but these methods can only distinguish free water and bound water in sludge, and cannot realize the four Quantification of state moisture

Chen et al. used thermogravimetric-differential thermal analysis (TG-DTA) to measure the binding energy of water and sludge particles, and distinguished the water distribution of sludge according to the difference of binding energy. The results showed that due to the sludge used in this method The sample is very small (10-15mg), the reproducibility of the experimental results is poor, and the error is about 30kJ / kg

Subsequently, some researchers used the method of thermal drying to determine the moisture content of four different forms according to the drying weight loss curve of sludge. The results showed that for municipal sludge with a moisture content of 90%, capillary water accounted for 64.93%, and surface bound water The proportion of bound water is 33.11%, and the proportion of bound water is 1.96%. However, the accuracy of thermal drying method is low. For sludge with low moisture content, the drying weight loss curve will miss the constant evaporation zone, which leads to the inaccurate determination of thermal drying method. Moisture of each part

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