SU599585A1

SU599585A1 - Method of drying gypsum,gypsum-concrete and gypsum-cement articles

Info

Publication number: SU599585A1
Application number: SU752197952A
Authority: SU
Inventors: Н.А. Глотова; В.С. Горшков; Т.М. Шапиро; С.В. Горшков; А.Г. Синайский; В.Н. Матиясевич
Priority date: 1975-12-24
Filing date: 1975-12-24
Publication date: 1981-03-30

Description

Изобретение относится к технике сушки капиллярно-пористых материалов, конкретно к сушке гипсовых, гипсобетонных и гипсоцементных изделий .The invention relates to a technique for drying capillary-porous materials, specifically to drying gypsum, gypsum concrete and gypsum-cement products.

Сушка капиллярно-пористых тел, например гипсобетонных и гипсовых изделий (гипсобетонных прокатных панелей и гипсовых блоков) и изделий из гипсоцементнопуццоланового вяжущего (оснований под полы) осуществляется, в основном, в сушилках туннельного типа при прямоточном движении теплоносителя и материала. Гипс относится к термонеустойчивым материалам, поэтому применение высоких температур теплоносителя для ин тенсификации процесса сушки и повышения эффективности оборудования связано с большими трудностями. Интенсификация процесса сушки изделий из гипсоцементнопуццоланового вяжущего, содержащих цемент для придания им водостойкости, еще более сложна, так как обезвоживание изделий не долж но нарушать процесс гидратации цемента.Drying of capillary-porous bodies, for example, gypsum concrete and gypsum products (gypsum concrete rolling panels and gypsum blocks) and products from gypsum-cement-pozzolanic binder (subfloors), is carried out mainly in tunnel-type dryers with direct-flow movement of the coolant and material. Gypsum is a thermally unstable material; therefore, the use of high temperatures of the heat carrier to intensify the drying process and increase the efficiency of the equipment is associated with great difficulties. The intensification of the drying process of gypsum-cement-pozzolanic binder products containing cement to give them water resistance is even more complicated, since dehydration of products should not disrupt the process of cement hydration.

Существует способ, позволяющий интенсифицировать процесс сушки гипсобетонных и гипсовых изделий, в котором для повышения производительности сушильных установок и улучшения качества сушку ведут в две стадии: до начала углубления зоны испарения и после нее. Интенсификация достигается в первой стадии,когда ‘испарение происходит с поверхности материала, за счет применений повышенных температур теплоносителя •θ до 150°С, влагосодержания порядка 60-70 г/кг с.в. и скорости, равнойThere is a method that allows to intensify the drying process of gypsum concrete and gypsum products, in which, to increase the productivity of drying plants and improve quality, drying is carried out in two stages: before the deepening of the evaporation zone and after it begins. Intensification is achieved in the first stage, when ‘evaporation occurs from the surface of the material, due to the application of elevated coolant temperatures • θ up to 150 ° C, moisture content of about 60-70 g / kg d.s. and speed equal

2,5-3 м/с. Длительность сушки в первой стадии составляет 8-8,5 ч и во второй 2,5-3 ч. Общее время суш15 ки гипсовых блоков составляет 10,5- ч, гипсобетонных прокатных панелей 12-14 ч. Для уменьшения неравномерности сушки по длине панелей в схеме сушильной установки предусмат-2.5-3 m / s. The drying time in the first stage is 8–8.5 hours and in the second 2.5–3 hours. The total drying time for 15 gypsum blocks is 10.5 hours, gypsum concrete rolling panels 12–14 hours. To reduce the unevenness of drying along the length of the panels in the scheme of the drying installation

м.m

Дальнейшая интенсификация процесса сушки гипсобетонных и гипсовых панелей и блоков до 8-10 ч может быть -25 достигнута при применении способа сушки, сущность которого заключается в разделении процесса на три стадии (зоны). В первой зоне процесс ведут при температуре теплоносителя 22030 250°С, влагосодержании 120-150 г/кг ривается· зона противотока длиной в и скорости 1,5-2 м/с, во второй влагосодержаи скорости 3,5- .Further intensification of the drying process of gypsum concrete and gypsum panels and blocks up to 8-10 hours can be achieved by -25 using the drying method, the essence of which is to divide the process into three stages (zones). In the first zone, the process is carried out at a coolant temperature of 22030 250 ° C, a moisture content of 120-150 g / kg is torn · a countercurrent zone of length b and a speed of 1.5-2 m / s, and in the second moisture content a speed of 3.5-.

с,from,

с. В . I .эоне при 170-200°С, нии 70-80 г/кг с.в.from. IN . I.eone at 170-200 ° С, research institutes 70-80 g / kg d.v.

м/с, в третьей стадии при 60-65° влагосодержании 60-70 г/кг с.в. и скорости 4,5-5 м/с. При этом в первой и второй зонах изделия обрабатывают в течение 3-3,5 ч, а в третьей зоне -в течение 2-2,5 ч.m / s, in the third stage at 60-65 ° moisture content of 60-70 g / kg d.v. and speeds of 4.5-5 m / s. Moreover, in the first and second zones, the products are processed for 3-3.5 hours, and in the third zone for 2-2.5 hours.

Цель предлагаемдго изобретения повышение качества сушки и сокращение продолжительности процесса.The purpose of the invention is to improve the quality of drying and reduce the duration of the process.

Для этого перед обдувом изделия прогревают насыщенным паром атмосферного давления до достижения ими температуры 90-95°С и в первой зоне поддерживают температуру теплоносителя 260-280°С, влагосодержание 160170 г/кг с.в. и скорость 1,5-2,0 м/с до снижения температуры изделий до 67-70^(2, а·.во второй эоне температуру теплоносителя поддерживают 210220°С, влагосодержание 85-90 г/кг с.в. и скорость 2,5-3,4 м/с до достижения изделиями температуры 58-60°С, причем прогрев ведут в течение- 0,751 ч, в. первой и второй зонах изделия выдерживают по 1,5-2,0 ч, а в третьей 0,75-1 ч.For this, before blowing, the products are heated with saturated steam of atmospheric pressure until they reach a temperature of 90-95 ° С and in the first zone the temperature of the coolant is maintained at 260-280 ° С, the moisture content is 160-170 g / kg dw. and a speed of 1.5-2.0 m / s until the temperature of the products decreases to 67-70 ^ (2, a... in the second aeon, the temperature of the coolant is maintained at 210 220 ° С, the moisture content is 85-90 g / kg r.v. and the speed 2.5-3.4 m / s until the products reach a temperature of 58-60 ° C, and heating is carried out for 0.751 hours, in the first and second zones of the product they withstand 1.5-2.0 hours, and in the third 0.75-1 h.

Сущность способа заключается в предварительной пропарке изделий насыщенным. паром атмосферного давления с доведением температуры изделий до 90-95°С. Как показали исследования, гипс не дегидратирует при 'данных температурах, если в нем есть избыточная влага. Однако при этом резко увеличивается коэффициент влагопроводности (в 7-8 раз), который определяет скорость движения влаги из внутренних слоев к наружным.Кроме того, при таких температурах изделий резко интенсифицируется процесс гидратации цемента и повышается прочность изделий из гипсоцементнопуццоланового вяжущего· (сантехкабин , оснований под полы и др.).The essence of the method consists in pre-steaming products saturated. atmospheric pressure steam, bringing the temperature of the products to 90-95 ° С. As studies have shown, gypsum does not dehydrate at given temperatures if there is excess moisture in it. However, at the same time, the moisture conductivity coefficient sharply increases (by 7-8 times), which determines the speed of moisture movement from the inner layers to the outer layers. In addition, at such temperatures of the products, the process of cement hydration is sharply intensified and the strength of products from gypsum-cement-pozzolanic binder · (santekhkabin, bases) under the floors, etc.).

После пропарки изделия поступают в зону сушки, где, благодаря большимзначениям коэффициента влагопроводности, можно осуществить значительную интенсификацию процесса сушки, применив теплоноситель с температурой 260-280°С, влагосо'держанием 160170 г/кг с.в. и скоростью 1,5-2 м/с. При этом температура изделий снижается с 90-95 до 67-70°С, часть влаги испаряется за счет тепла, аккумулированного самими изделиями и постепенно, по мере уменьшения их влажности, начинает сказываться влияние коэффициента термовлагопроводности, который оказывает благоприятное действие на движение влаги из внутренних слоев к наружным, так как температура наружных слоев изделий понижается быстрее.After steaming, the products enter the drying zone, where, thanks to the large values of the coefficient of moisture conductivity, it is possible to significantly intensify the drying process by using a coolant with a temperature of 260-280 ° C, moisture content of 160,170 g / kg and a speed of 1.5-2 m / s. At the same time, the temperature of the products decreases from 90-95 to 67-70 ° C, part of the moisture evaporates due to the heat accumulated by the products themselves and gradually, as their humidity decreases, the influence of thermal moisture conductivity begins to affect, which has a beneficial effect on the movement of moisture from internal layers to the outer, as the temperature of the outer layers of the product decreases faster.

Далее изделия поступают во вторую • эону сушки, где с целью дальнейшей интенсификации движения влаги из внутренних слоев материала к наруж- _;ным за счет коэффициента термовлагопроводн-ости, который достигает своего максимального значения, и интенсификации процесса испарения влаги, влагосодержание воздуха теплоносителя снижается и. достигает величины влагосодержания, равной 85-90 г/кг с.в. при температуре. 210-220°С и скорости 2,5-3,4 м/с. При этом температура изделий снижается до 58-60°С, причем падение температуры происходит быстрее в поверхностных слоях, чем в центральных, что способствует перемещению влаги из центра к наружным слоям. Кроме того, часть влаги испаряется за счет тепла·, аккумулированного изделиями.Further, the products enter the second • eon of drying, where in order to further intensify the movement of moisture from the inner layers of the material to the outside _; due to the coefficient of thermal moisture conduction, which reaches its maximum value, and the intensification of the process of evaporation of moisture, the moisture content of the coolant air decreases and. reaches a moisture content of 85-90 g / kg d.s. at a temperature. 210-220 ° С and speeds of 2.5-3.4 m / s. At the same time, the temperature of the products decreases to 58-60 ° C, and the temperature drops faster in the surface layers than in the central layers, which helps to move moisture from the center to the outer layers. In addition, part of the moisture evaporates due to the heat accumulated by the products.

В третьей зоне при углублении испарения температуру теплоносителя снижают до_t60-65°C для того, чтобы · не допустить перегрева верхних обезвоженных слоев' материала. Снижение температуры теплоносителя во второй и третьей эонах осуществляется за счет организации подсоса наружного воздуха. Параметры воздуха в третьей зоне следующие: температура 6065°С, влагосодержание 65-70 г/кг с.в., скорость 4,5-5,0 м/с. Общее время прогрева и сушки гипсобетонных прокатных панелей, гипсовых блоков и оснований под полы при этом снижается до 5-6 ч. Причем в зоне прогрева изделия выдерживают 0,75-1 ч в первой и второй зонах и в третьей зоне 0,75-1 по 1,5-2 чIn the third zone, when the evaporation is deepened, the coolant temperature is reduced to _t 60-65 ° C in order to prevent overheating of the upper dehydrated layers of the material. Reducing the temperature of the coolant in the second and third eons is due to the organization of suction of external air. The air parameters in the third zone are as follows: temperature 6065 ° C, moisture content 65-70 g / kg d.v., speed 4.5-5.0 m / s. The total heating and drying time of gypsum concrete rolling panels, gypsum blocks and subfloors under this is reduced to 5-6 hours. Moreover, in the heating zone, the products are kept for 0.75-1 hours in the first and second zones and in the third zone 0.75-1 1.5-2 hours

ч.h

сушки можетdrying can

Предлагаемый процесс быть организован в действующих сушильных установках туннельного типа. При этом в 1,5-2 раза снижается время сушки и на 25-30% повышается экономичность работы утановок.The proposed process should be organized in existing tunnel-type drying plants. At the same time, the drying time is reduced 1.5-2 times and the efficiency of the work of the plants increases by 25-30%.

Claims

. The invention relates to a technique for drying capillary-porous materials, specifically to the drying of gypsum, gypsum-concrete and gypsum-cement products. Drying of capillary-porous bodies, for example, gypsum-concrete and gypsum products (gypsum-concrete rolling panels and gypsum blocks) and products made from gypsum-cement-puztsolannogo iznayuyu (bases under floors), are mainly carried out in tunnel-type dryers with direct flow of heat-transfer material and gypsum material and Gypsum material and Gypsum material under the Gypsum-type material. to thermally unstable materials, therefore, the application of high heat carrier temperatures for the tenification of the drying process and the increase in the efficiency of equipment with great difficulties. The intensification of the process of drying products made from gypsum-cement-pussolanic to cement containing to make them water-resistant is even more complicated, since dehydration of products does not interfere with the process of cement hydration. There is a way to intensify the drying process of gypsum concrete and gypsum products, in which, to increase the productivity of drying plants and improve the quality, drying is carried out in two stages: before the beginning of the deepening of the evaporation zone and after it. Intensification is achieved in the first stage, when evaporation occurs from the surface of the material, due to the use of elevated heat carrier temperatures up to 150 ° C, moisture content of about 60-70 g / kg d.s. and speeds equal to 2.5-3 m / s. The drying time in the first stage is 8-8.5 hours and in the second 2.5-3 hours. The total drying time of the gypsum blocks is 10.512 hours, gypsum-concrete rolling panels 12-14 hours. To reduce the non-uniformity of drying along the length of the panels the drying unit is provided for - a countercurrent zone of 12 m in length. Further intensification of the drying process of gypsum-concrete and gypsum panels and blocks up to 8-10 hours can be achieved by applying the drying method, the essence of which consists in dividing the process into three stages (zones). In the first zone, the process is carried out at a heat carrier temperature of 220,250 ° C, moisture content of 120-150 g / kg G, B. And the speed of 1.5-2 m / s, in the second zone at 170-200 ° С, moisture content 70-80 g / kg d.v. and speeds of 3.54 m / s, in the third stage at 60-65 0, moisture content 60-70 g / kg alt. and speeds of 4.5-5 m / s. In this case, in the first and second zones, the products of the o.batch are processed for 3-3.5 hours, and in the third zone, for 2-2.5 hours. The aim of the invention is to improve the quality of drying and shorten the process time. To do this, before blowing the products, they heat them with saturated steam at atmospheric pressure until they reach a temperature, and in the first zone they keep the temperature of the coolant at 260-280 ° C and their moisture content is 160170 g / kg d.s. and the speed of 1.5-2.0 m / s to reduce the temperature of the products to 67-70 ° C, and in the second zone the temperature of the coolant is maintained at 210220 s, the moisture content is 85-90 g / kg d.s. and a speed of 2.5-3.4 m / s until the products reach a temperature of 58-60 ° C, and the heating is carried out for 0.751 h. the first and second zones of the product are kept for 1.5-2.0 hours, and in the third, 0.75-1 - h. The essence of the method consists in the preliminary steaming of the products with saturated, steam of atmospheric pressure with bringing the temperature of the products to 90-95 ° C. As research has shown, gypsum does not dehydrate at given temperatures if it contains excessive moisture. However, this dramatically increases the moisture coefficient (, 7-8 times), which determines the speed of moisture from the inner layers to the outer layers. In addition, at these product temperatures, the process of hydration of cement is greatly intensified and the strength of gypsum-cement-pulverized products increases; (sanitary engineering cabins, underfloor bases, etc.). After steaming, the products enter the drying zone, where, due to the large values of moisture-throughput ratio, a significant intensification of the drying process can be carried out. using a coolant with a temperature of 260-2-80 s, moisture content of 160170 g / kg s, c. and at a speed of 1.5-2 m / s. At the same time, the temperature of the products reduces from 90-95 to 67-70s, some of the moisture evaporates due to the heat accumulated by the products themselves and gradually, as their humidity decreases, the effect of Thermal moisture coefficient, which has a beneficial effect on the movement of moisture from the inner layers to the outer, since the temperature of the outer layers of products is faster. Further, the products enter the second zone cyuiKH, where, in order to further densify the movement of moisture from the inner layers of the material to the outer layers due to the coefficient of thermal moisture, which reaches its maximum value, and intensify the process of evaporation of moisture, the moisture content of the coolant air decreases. reaches a moisture content equal to 85-90 g / kg d.c. at a temperature. 210-220 C and speeds of 2.5-3.4 m / s. At the same time, the temperature of products decreases to 58-60 0, and the temperature drops faster in the surface layers than in the central ones, which promotes the movement of moisture from the center to the outer layers. In addition, some of the moisture evaporates. accumulated products. in the third zone, with the deepening of evaporation, the temperature of the heat transfer medium is reduced to 60-65 s in order to prevent overheating of the upper dehydrated material layers. The temperature of the coolant in the second and third zones is reduced by organizing the intake of outside air ;. The parameters of air in the third zone are as follows: temperature 6065 C, moisture content 65-70 g / kg s. at. speed 4, 5-5, 0 m / s. The total time of warming up and drying of gypsum-concrete rolling panels, gypsum blocks and bases under the floor is reduced to 5-6 hours. Moreover, the product warms up to 0.75-1 hours in the heating zone, and 1.5-2 hours in the first and second zones and in the third zone 0.75-1 hours. The proposed drying process can be organized in existing tunnel-type drying units. At the same time, the drying time is reduced by a factor of 1.5–2 times and the efficiency of setting operations increases by 25–30%. Claims 1. Method for drying gypsum, gypsum-concrete and gypsum-cement products. for example, blocks, panels and basement under the floors, by moving them through three zones and blowing with heat carrier, each having individual jiapaMeTpbi in each zone, supported in the last zone by temperature within 60-65 ° C, moisture content 65-70 g / kg s. at. and speeds of 4.55.0 m / s, characterized in that, in order to improve the quality of drying and reduce the duration of the process, before blowing the product, it is heated with saturated vapor of atmospheric pressure until they reach a temperature of 90-95 ° C, and the temperature of the coolant is maintained in the first zone equal to 260-280 ° С, moisture content equal to 160-170 g / kg s.v. and a speed of 1.5-2.0 m / s to reduce the temperature of the products to BT-TO-s, and in the second zone the temperature of the coolant is maintained 210-220 ° C, the moisture content is 85-. , 90 g / kg.s.v, and the speed of 2.5-3.4 m / s until the product reaches a temperature of 58-60 C.

2. The method according to claim 1, characterized by the fact that the heating is carried out in the confluence of 0.75-1 h, in the first and second zones of the product stand at 1.52, 0 h, and in the third 0.75-1 h .