Method for accurately measuring density of desulfurized gypsum slurry in laboratory
阅读说明：本技术 一种实验室准确测量脱硫石膏浆液密度的方法 (Method for accurately measuring density of desulfurized gypsum slurry in laboratory ) 是由 杜佳 揭其良 王飞 李超 曲立涛 齐晓辉 于洪海 王德鑫 于 2019-08-19 设计创作，主要内容包括：本发明涉及一种实验室测量石膏浆液密度的方法,特别涉及一种能够在实验室中准确的测量石灰石-石膏湿法烟气脱硫系统运行过程中石膏浆液密度的方法。本方法主要通过直接使用广口瓶取样,利用广口瓶的膨胀系数换算出广口瓶在石膏浆液运行温度下的体积,通过测量石膏浆液的重量,计算出石膏浆液的准确密度。本方法克服了脱硫石膏浆液温度高、易沉淀、密度和温度不固定等不利于密度测定的问题,将石膏浆液的密度准确测量出来,并且方法操作简便、快捷,对于实验条件和器具没有严格的限制。(The invention relates to a method for measuring gypsum slurry density in a laboratory, in particular to a method capable of accurately measuring the gypsum slurry density in the operation process of a limestone-gypsum wet flue gas desulfurization system in the laboratory. The method mainly comprises the steps of directly sampling by using a wide-mouth bottle, converting the volume of the wide-mouth bottle at the running temperature of gypsum slurry by using the expansion coefficient of the wide-mouth bottle, and calculating the accurate density of the gypsum slurry by measuring the weight of the gypsum slurry. The method overcomes the problems that the desulfurized gypsum slurry is high in temperature, easy to precipitate, unfixed in density and temperature and the like, which are not beneficial to density determination, accurately measures the density of the gypsum slurry, is simple, convenient and quick to operate, and has no strict limitation on experimental conditions and appliances.)
1. A method for accurately measuring the density of desulfurized gypsum slurry in a laboratory is characterized by comprising the following operation steps:
1) the mass m of the dried jar with lid was weighed at room temperature0While recording the room temperature t1；
2) At the same room temperature, the wide-mouth bottle is filled with pure water, then the bottle cap is covered to enable the excessive water to overflow, the water on the outer surface of the wide-mouth bottle is sucked dry by using filter paper, the weight m of the wide-mouth bottle filled with the pure water is recorded, and the weight m of the wide-mouth bottle is weighed again1；
3) In the pure water density meter, t is inquired and recorded1Density rho of pure water at temperature1；
4) The volume V of the jar at room temperature was calculated as follows1
In the formula:
V1volume of jar at room temperature, mL;
m1-mass of covered jar filled with pure water, g;
m0mass of dried capped jars, g;
ρ1density of pure water at room temperature, kg/m3。
5) Bringing the jar to a gypsum slurry sampling site, covering the jar, flushing the outside of the jar with the gypsum slurry for 5-10 minutes, and recording the temperature t of the slurry2When the wide-necked bottle is unanimous with the thick liquid temperature after, directly with the sampling of wide-necked bottle, fill in behind the thick liquid tight bottle lid of lid and make unnecessary thick liquid spill over, wash the outside thick liquid of wide-necked bottle clean with the pure water, with the water of filter paper blotting wide-necked bottle surface, weigh once more, the record is full of the quality m of the wide-necked bottle of thick liquid2。
6) Calculate the jar at t using the formula2Volume at temperature V2
V2＝V1[1+γ(t2-t1)]
In the formula:
V2volume of jar at slurry temperature, mL;
V1volume of jar at room temperature, mL;
gamma-volume expansion coefficient of wide-mouth bottle, 25X 10 for soda lime glass-6Borosilicate glass is 10 multiplied by 10-6；
t2-measuring the temperature of the slurry at room temperature;
t1-measuring the room temperature, DEG C, of a wide-necked bottle filled with pure water.
7) And (3) calculating the result: gypsum slurry density ρ2Calculated by the following formula
In the formula:
ρ2density of desulfurized gypsum slurry, kg/m3；
m2-mass of covered jar filled with gypsum slurry, g;
m0mass of dried capped jars, g;
V2volume of jar at slurry temperature, mL.
2. The method for laboratory accurate measurement of the density of desulfurized gypsum slurry according to claim 1, wherein the measurement is carried out using a jar.
3. The method for laboratory accurate measurement of the density of desulfurized gypsum slurry according to claim 1, wherein the effect of slurry temperature on volume is converted and calculated using the volumetric expansion coefficient of the jar.
4. The method for accurately measuring the density of desulfurized gypsum slurry in laboratory according to claim 2, wherein the jar is made of soda lime glass or borosilicate glass and has a cylindrical structure with a bottom diameter of 3cm, a height of 7cm and a volume of 50mL, and the mouth of the jar has scale lines; the wide-necked bottle is covered with the lid, and the bottle lid material is the same with the body, and is 2cm thick, and bottle lid bottom and bottle lid edge parallel and level cover solid construction, and the contact surface of bottle lid and bottleneck is ground the structure.
Technical Field
The invention relates to a method for measuring gypsum slurry density in a laboratory, in particular to a method capable of accurately measuring the gypsum slurry density in the operation process of a limestone-gypsum wet flue gas desulfurization system in the laboratory.
Background
In a limestone-gypsum wet flue gas desulfurization system of a thermal power plant, the density of gypsum slurry is one of very important operating parameters, and in normal operation, the density of the gypsum slurry is controlled to be 1080-3When the measured density is higher than 1120kg/m3When the density is reduced to 1080kg/m, the gypsum discharge pump is started to remove gypsum3The gypsum discharge pump should be stopped. Otherwise, when the density of the gypsum slurry is too high, the system resistance and energy consumption are increased, the system is scaled and blocked, and when the density of the gypsum slurry is too low, the desulfurization efficiency, the gypsum dehydration effect and the like are influenced. It must be accurately measured and supervised.
Due to the complex technological process of the wet desulphurization system and the severe field operation environment, the measurement results of most of the slurry density online measurement devices are inaccurate or cannot be maintained to be accurate for a long time, and the online densimeter needs to be regularly compared, supervised and monitored in a laboratory, so that the gypsum slurry density result measured in the laboratory can very accurately reflect the true value of the gypsum slurry density in operation.
The characteristics of the gypsum slurry in the limestone-gypsum wet desulphurization system mainly comprise the following points:
(1) the temperature is high. The temperature of the gypsum slurry in operation is higher due to the absorption of heat in the flue gas, and meanwhile, the gypsum slurry is influenced by the capacity of a unit, the operation load, the weather temperature and the like and fluctuates within a certain range. Typically, the temperature of the gypsum slurry during operation will be around 55 ℃.
(2) Is not uniform. The desulfurized gypsum slurry is a solid-liquid two-phase suspension, continuous stirring is needed in actual operation to ensure solid-liquid uniformity, and once stirring is stopped, solid substance gypsum particles can be precipitated in a short time to cause solid-liquid two-phase separation.
(3) Is not fixed. In actual operation, the density of the gypsum slurry is not fixed but varied within a certain range, and when the density is increased to the upper limit of the range, the gypsum discharge pump is started to perform the gypsum removing operation, and when the density is decreased to the lower limit of the range, the gypsum removing operation is stopped.
The above three-point characteristics of the desulfurized gypsum slurry make the density measurement unsuitable for the existing density measurement methods and difficult to accurately measure. Thus, while there are many methods for measuring the density of a desulfurized gypsum slurry, to date there has been no standard method for measuring the density of a gypsum slurry in operation with great accuracy.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for accurately measuring the density of gypsum slurry in the operation process of a limestone-gypsum wet flue gas desulfurization system in a laboratory.
The technical scheme adopted by the invention for solving the problems is as follows: a method for accurately measuring the density of desulfurized gypsum slurry in a laboratory is characterized by comprising the following operation steps:
1) the mass m of the dried jar with lid was weighed at room temperature0While recording the room temperature t1；
2) At the same room temperature, the wide-mouth bottle is filled with pure water, then the bottle cap is covered to enable the excessive water to overflow, the water on the outer surface of the wide-mouth bottle is sucked dry by using filter paper, the weight m of the wide-mouth bottle filled with the pure water is recorded, and the weight m of the wide-mouth bottle is weighed again1；
3) In the pure water density meter, t is inquired and recorded1Density rho of pure water at temperature1；
4) The volume V of the jar at room temperature was calculated as follows1
In the formula:
V1volume of jar at room temperature, mL;
m1-mass of covered jar filled with pure water, g;
m0mass of dried capped jars, g;
ρ1density of pure water at room temperature, kg/m3。
5) Bringing the jar to a gypsum slurry sampling site, covering the jar, flushing the outside of the jar with the gypsum slurry for 5-10 minutes, and recording the temperature t of the slurry2When the wide-necked bottle is unanimous with the thick liquid temperature after, directly with the sampling of wide-necked bottle, fill in behind the thick liquid tight bottle lid of lid and make unnecessary thick liquid spill over, wash the outside thick liquid of wide-necked bottle clean with the pure water, with the water of filter paper blotting wide-necked bottle surface, weigh once more, the record is full of the quality m of the wide-necked bottle of thick liquid2。
6) Calculate the jar at t using the formula2Volume at temperature V2
V2＝V1[1+γ(t2-t1)]
In the formula:
V2volume of jar at slurry temperature, mL;
V1volume of jar at room temperature, mL;
gamma-volume expansion coefficient of wide-mouth bottle, 25X 10 for soda lime glass-6Borosilicate glass is 10 multiplied by 10-6；
t2-measuring the temperature of the slurry at room temperature;
t1-measuring the room temperature, DEG C, of a wide-necked bottle filled with pure water.
7) And (3) calculating the result: gypsum slurry density ρ2Calculated by the following formula
In the formula:
ρ2density of desulfurized gypsum slurry, kg/m3；
m2-mass of covered jar filled with gypsum slurry, g;
m0mass of dried capped jars, g;
V2volume of jar at slurry temperature, mL.
The invention uses the wide-mouth bottle for measurement, and converts and calculates the influence of the slurry temperature on the volume of the wide-mouth bottle by using the volume expansion coefficient of the wide-mouth bottle. The wide-mouth bottle is made of soda lime glass or borosilicate glass and is of a cylindrical structure, the diameter of the bottom surface of the wide-mouth bottle is about 3cm, the height of the wide-mouth bottle is about 7cm, the volume of the wide-mouth bottle is about 50mL, and the mouth of the wide-mouth bottle is provided with scale marks; the wide-necked bottle is covered with the lid, and the bottle lid material is the same with the body, and is about 2cm thick, and bottle lid bottom and bottle lid edge parallel and level cover solid construction, and the contact surface of bottle lid and bottleneck is the ground structure.
Compared with the prior art, the invention has the following advantages and effects:
(1) the influence of the volume change of the container caused by the influence of higher temperature of the sample on the test result is avoided;
(2) the influence of uneven sampling on the test result caused by easy precipitation of the sample is avoided;
(3) the test result can not be influenced by temperature change, concentration change and the like of the sample caused by desulfurization working condition change.
(4) No special test apparatus is needed, no requirement is provided for the experimental environment, and the device is suitable for daily monitoring and detection tests in various laboratories.
The method has the advantages that inconvenience and influence on measurement caused by three characteristics of the desulfurized gypsum slurry in operation are respectively eliminated, and the accuracy and precision of the measurement result can be ensured. Moreover, the device is simple, the operation method is simple, convenient and quick, special instruments and equipment are not needed, and the device is not influenced by complicated conditions, working conditions and the like on site.
Drawings
Fig. 1 is a schematic structural view of a jar in an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
Fig. 1 is a wide-necked bottle used in this embodiment, the wide-necked bottle is made of glass, and is cylindrical, and the bottom surface diameter is about 3cm, and is about 7cm high, and the volume is about 50mL, and the bottleneck has the scale mark, and the wide-necked bottle area lid, and the bottle lid material is the same with the body, and the bottle lid is about 2cm thick, bottle lid bottom and bottle lid edge parallel and level, and the bottle lid is solid structure, and the contact surface of bottle lid and bottleneck is the ground structure.