The power plant enters survey of coal material whole to hydrate to restrict element and answer act

  • 1. Sampling means

    Sampling means is main influencing factor. National level is right of total moisture adopted a method to do go into particulars, pledge in coal relatively even circumstance falls, can obtain ideal result according to the method in national level completely. But, the case of the coal that enter a plant that gets at present is very complex, for example: The mixed coal that supplier place supplies is used on carriage tool " statified " pile up means, factitious perhaps ground waits a circumstance a moment to give to the affusion in coal take the difficulty with have representative coal sample to bring certain. Via selectiving examination the result shows, the total moisture of railroad car ground floor is worth apparent prep above to carry a layer on the head. Analysing its reason is: Coal has added water from the dot that offer money sets out, surface layer evaporates as a result of insolation, accordingly, total moisture on the low side, and because ground floor evaporates slow and on the high side. Be aimed at this kind of circumstance, answer to inspect actual condition to adjust sampling pattern on the foundation of national level.

    2. Make the moisture loss in shape course

    In the process that make appearance, especially below the case with total moisture bigger content, crusher and the attrition heat that sample attrition place produces and the strong air current of the generation when crusher works are moisture losing main reason. In the meantime, stick corrupt the moisture prediction of a person's luck in a given year in equipment surface. In addition, sample also can cause partial moisture prediction of a person's luck in a given year in process of sophisticate, division, sift out. Anyhow, the move that makes appearance is more, moisture prediction of a person's luck in a given year is larger.

    3. Weather, gush drenchs

    In sampling process, because rain or gush drenchs wait for a reason, cause total moisture to increase, this is the thing that working middling comes up against.

    4. A few wrong operation method that be in are put in assay

    Determine to total moisture the effect is more apparent is dry time and dry temperature, the dry time that the sort of the content of the moisture in coal and coal decides to its need is different, accordingly, undertake besides the dry time that provides strictly according to the place in national level method dry outside, must do inspectability test, in order to check coal sample whether completely dry already, be like not dry should farther dry, until till quality is constant. And some staff members for pursuit fast, often omit inspectability experiments, this is wrong. Dry temperature affects expression to be in to what determine: Temperature is too low, the moisture in coal cannot complete transgression, temperature is exorbitant the oxidation that causes sample, both all causes an effect as a result to determining. What must point out is national level already abolished quick way, but still using sometimes at present. This method passes as a result of adoption temperature tall (dry temperature is 145 ℃ ± 5 ℃ ) , cause sample oxidation easily already, may make again the coal of pitch of a few low coal (be like: Lignite and long blaze coal) volatilize minute of transgression. According to examining concerned data, lignite volatilizes with what grow blaze coal cent transgression temperature is 130 ~ 170 ℃ .

    5. Sample is putting the moisture loss in letting off Cheng

    Because all sorts of reasons cause sample,must depositing proper time is the trouble that encounters in working middling. Sample is in in depositing a process, because water is divided in air to volatilize mediumly,can cause moisture loss, and, deposit time loss of longer moisture content is bigger.

    Put forward as follows to settle way in the light of above influencing factor:

    1. Those who raise sampling is representative

    Mechanical sampling is accepted have method of representative a kind of sampling most. If collect labour of choose and employ persons to be in sampling of railroad car coping, those who collect is the sample with inferior moisture, and after using automatic sampling machine, the sampling head of its screw type gets bottom from coping, those who collect is the sample of whole section, accordingly, of its sample representative stronger. Because mechanical sampling is had good representative, answer to be popularized energetically, but blocking the problem such as coal up is the problem that is badly in need of solving at present. When using artificial sampling, detecting in the process if discover moisture content " statified " circumstance, set out from the representative angle that raises sampling, answer to go up in the foundation according to the method in national level, the consideration is right " rock-bottom " sample has sampling observation.

    Can mingle two sample gross sample to undertake examining, also can take two result the weighted average to regard as detect finally result.

    2. Reduce the moisture loss in the process that make appearance

    The moisture loss in wanting to reduce the process that make appearance must notice: Make appearance inside air cannot intense convection, and without heat source; The process that make appearance should be finished quickly in order to reduce moisture loss, the sample that has made applies sealed container to had been installed, send a laboratory quickly.

    3. Crusher respect should note the following problem

    A) the requirement uses low speed crusher, general rotate speed does not exceed Min of / of 300 ~ 400r, otherwise, can form strong air current, and give out heat easily, the loss of aggravate moisture; B) the crusher that uses sealed formula divides a loss with reducing water; C) crusher should not give out heat apparently when the job. 3, solve weather, gush to drench because rain,the influence to moisture is aimed at, gush drenchs wait for a reason to make total moisture raises a question, besides keep away from as far as possible the sampling when raining, do not install liner spray before sampling is nodded, or outside the measure such as sampling having again after the wet coal purify the surface first, can consult to determine to total moisture about the regulation the value undertakes corrective.

    4. Settle the moisture loss in existence process

    Solve the moisture loss in depositing a process to should note the following problem: A) sealed step has been made when sample is deposited, sealed bag or sealed bottle reduce moisture loss effectively. B) will whole batch coal presses proper time or coal quantity cent becomes a certain number of cent kind, determine quickly to distribute kind each respectively, serve as final result with dividing the total moisture weighted average of appearance each, achieve with this shorten the purpose that deposits time. C) if sample is deposited for long, should calculate coal sample during transit moisture loss amount. Specific means is: The sample that will made weighs out the total mass M4 of coal sample and bottle first after bottle, make good record. When determining, because sample is deposited for long, the moisture content that commonly can a few brandish are sent condenses on bottle wall, when the loss in computational road is measured, answer to calculate this part moisture inside. Particular way is open cap, all put bottle and cap sweatbox, want 50 ℃ of 45 ― to fall dry to bottle wall till anhydrous bead. Be taken out instantly and measure the total mass M6 that gives appearance and bottle, next, after mixing sample, put in 105 ~ 110 ℃ determine further total moisture, press type has corrective consideration:

    ω (Mt) = ω (M1) + [1 - (M1) ] × ω (M) ω (M) -- the total moisture that 105 ~ of ― determine below 110 ℃ is worth (quality mark) ; ω (M1) -- ― sample during transit mark of moisture losing quality, ω (M1) = M4 - M 6 M 4 - M 5; M4 -- the total mass that the sample when ― bottle adds bottle; M5 -- the quality of ― empty bottle; M6 -- 50 ℃ issue 45 ~ of ― dry hind the total mass that sample adds bottle.

    5. Normative experiment method arrives to get accurate

    Data, must normative experiment method, the key when determining notes the following problem: A) abolish is fast law, use new national level method; B) when the experiment, answer to make good inspectability test seriously; C) the sample with small degree of coalification should use a nitrogen dry method.

    Measure the analysis that decides influencing factor to coal total moisture through above, offerred a means of settlement, in carrying out a process, obtained better economic benefits.