SORBING MATERIAL BASED ON SLUDGE OF THERMOELECTRIC POWER STATION Текст научной статьи по специальности «Химические технологии»

Лгтература

1. http://www.dklc.kmu.gov.ua.(forest).

2. Технология целлюлозно-бумажного производства. Справочные материалы: в 3-х томах. Т.1. Сырье и поизводство полуфабрикатов. Ч. 2. Производство полуфабрикатов. - ВНИБ. - СПб.: Политехника, 2003. - 633 с.

3. Зильберглейт М.А. Оптимизация процесса получения целлюлозы из древесины лиственных пород варкой с водными растворами уксусной кислоты в жидкой фазе / М.А. Зильберглейт, Б.С. Симхович, Т.В. Корней-чик // Бум. пром-сть. - 1991. - № 12. - С. 4.

4. Примаков С.П., Барбаш В.А., Черьопкша Р.1. Ви-робництво сульфатно! та органосольвентно! целюлози. Навчальний поабник - Ки!в: ЕКМО, 2009. - 279 с.

5. Симхович Б.С. Исследование процесса делигни-фикации древесины водными растворами уксусной кислоты / Б.С. Симхович, М.А. Зильберглейт, В.М. Резников // Химия древесины. - 1986. - №3. - С. 34-38.

6. Пен Р.З., Катализируемая делигнификация древесины пероксидом водорода и пероксикислотами / Р.З. Пен, Н.В. Каратникова // Химия растительного сырья. - 2005. -

№3. - С. 61-73.

7. Барабаш В.А. Органосольвентные способы получения волокнистых полуфабрикатов из пшеничной соломы / В.А. Барабаш, И.В. Трембус // Энерготехнология и ресурсосбержение. - 2009. - №1. - С 37-41.

8. Барабаш В.А. Бумага и картон из стеблей кенафа и сорго сахарного / В.А. Барабаш, И.В. Трембус, И.Н. Ок-сентюк // Химия растительного сырья. - 2014. - №4. - С. 271-278.

9. Примаков С.Ф. Лабораторный практикум по целлюлозно-бумажному производству: Учебн. пособие для вузов / С.Ф. Примаков, В.П. Миловзоров, М.С. Кухникова, И.М. Царенко. - М.: Лесн. пром-сть. - 1980. - 168 с.

10. Барбаш В.А. Одержання солом'яних волокнистих натвфабрикатав пероцтовим способом дел^шфжацп / В.А. Барбаш, 1.В. Трембус, О.С. Гапон, В.М. Шевченко // Науков1 в1сл НТУУ «КП1», - 2010, - № 3, - С. 42-49.

11. Ивахненко А.Г. Индуктивный метод самоорганизации моделей сложных систем. - Киев: Наук. Думка, 1982. - 296 с.

SORBING MATERIAL BASED ON SLUDGE OF THERMOELECTRIC POWER STATION

Khantimerova Yu.M.

industrial engineer, New Structures&Technologies Ltd.

Khantimerov S.M. cand. phys.- math. sciences research fellow

E.K. Zavoisky Physical-Technical Institute RAS

ABSTRACT

The composition and physical properties of sludge from thermoelectrical power stations (TPSs) chemical water treatment were investigated. The sludge sample with reduced moisture content was prepared using thermal drying method. On the basis of the sample obtained, the sorption material was developed using a modeling of the composite's component composition and different manufacturing technologies. Sorption properties of the developed material were investigated.

Keywords: composite material, sorption, chemical water treatment sludge, waste

One of the priority problems concerning all areas of human life is the problem of waste material recycling. According to official data no more than 2% of feedstock extracted from the depths is converted into a final product, the remaining 98%

- is waste. [1]. A significant amount of waste is generated by industrial plants including TPSs. During the preliminary water treatment at TSPs which includes clarification of water (liming and coagulation processes), as well as alkalinity reducing and partial softening, a significant amount of water treatment waste

- chemical water treatment sludge is produced. The sludge is a serious problem in the production cycle of the thermoelectrical power stations. Traditional methods for solving this problem involve a number of economic and environmental actions, however they do not provide the desired effect. In this regard, actual is the search for new sludge recycling techniques that reduce the environmental.

In this paper the experimental results on the composition and physical properties of sludge based composite material for its use as secondary resource are presented.

Using an automatic moisture analyzer MA-150 it was found that the initial water content in sludge is 95%. Thus, the sludge settling should be carried for thickening of the solid phase and water removal. After filtration, the solid phase of sludge was subjected to heat drying.

Sludge dehydration was carried out using two methods of thermal:

- a one-step exposure to temperature;

- sequential firing at different temperatures.

It was found that the material subjected to sequential firing with temperature rising from 150 °C to 800 °C, decomposed into fraction slower than the material fired at 200 °C only once. Thus, the most suitable drying process is a single-stage thermolysis at which the adhesion of sludge particles is not observed. The proposed method allows to obtain a product with a solids content of 95-100% without changing the original composition of matter having the largest specific surface.

The fractional composition of the sludge was determined using sieve method in accordance with [2] (Fig.1).

<0,05mm 0,05-0,1 mm 0,1-0,25 mm 0,2 5-0,5 m m 0,5-1 mm 1-1,5 m m

Particle size

Fig.1. Granulometric composition of the sludge.

After drying the sludge acquires bulk powder properties, analysis [3], including laboratory documentation [4], a table of that allows achieving uniformity and possibilities of use as an sludge component composition was formed (Table 1). additive in composite materials. According to the literature

Table 1.

Sludge component composition

Sludge component composition: wt. %

Calcium carbonate 85

Iron hydroxides 10

Gypsum 5

Total 100

The predominant content of calcium carbonate in the sludge is also confirmed by experimental data. X-ray analysis showed that the sludge consists mostly of calcium carbonate - CaCO3.

The analysis of foreign and Russian experience led to identify a number of existing uses of sludge as an additive in manufacturing of composite materials:

- as a filler in the rubber and rubber products technology

[5];

- in the production of ceramic and cement bricks [6-9];

- in asphalt mixtures [10, 11];

- as a chemical improver in the processing of acidic soils and reclamation of quarries [10].

However, the most promising method is the use of sludge waste as sorbent. Due to the increasing rate of population growth in large cities, the use of petroleum and oil products also increases. These products are one of the main toxicants. One of the solutions in the field of water treatment is the use of sorption method, the demand for which is confirmed by the scale and

diversity of different types of sorbents. Most often the granular activated carbon is used as an adsorbent. But its high cost necessitates reusability after appropriate regeneration, leading to additional economic and energy costs and secondary water pollution. Therefore, more appropriate for the implementation of this method the use of environmentally friendly industrial waste: water treatment sludge and ashes as sorbents is seen. The use of carbonate sludge and ash as sorption material is due to the low cost of materials, availability, and the possibility of their use as an oil sorbent.

The laboratory sample was prepared using sludge dried at 200 °C. The dried sludge was sifted through a sieve to recover sludge particles smaller than 0.1 mm. The remainder bulk material was subjected to grinding to produce particles of the same size.

Modeling of the material's composition was carried out by measuring the percentage of sludge and ash. Uniform mixing of the substances was performed using an ultrasonic disperser.

To this powder mixture distilled water was added, immersing the outlet end of the dispersant to the flask with the solution. The treated solution was placed in an oven and subjected to one-step thermolysis at 200 °C for 30 minutes. To obtain a homogeneous mixture of dehydrated fractional composition a mortar and pestle was used. The prepared powder was placed to the mold and pressed, and the samples of the composite material were weighed on an analytical balance.

Modeling of the material's composition was carried out based on the evaluation of the sorbents effectiveness criteria:

The highest water capacity had samples with 100% ash content. At the same time the samples had a large wetting speed during the first 45 seconds of the experiment. Next, after 120 seconds after immersion in water, the samples reached saturation point and lost its original shape. This fact suggests the possibility of sorbent entrainment during cleaning.

With an increase in the percentage of sludge in the composite material, water capacity value reduced significantly. This suggests a greater degree of hydrophobicity of the resulting sludge with respect to ash. When the content of the sludge in composite material was more than 50% to reach the saturation point, the sample degradation was not observed. Thus, the insertion of the sludge to composite material can increase the time a sorbent possible remaining in water without the risk of entrainment of its particles, being achieved by significantly reducing of wettability.

The possibility of removing the oil film from the water surface using the obtained material was also investigated.

- the value of water capacity (sorbent should have low wettability);

- sorption capacity (the highest rates are necessary to be achieved);

- sorption rate (in the case of accidental oil spills the determining factor is the rate of liquidation of the accident).

Experimental study of water capacity was carried out is in accordance with [12]. The experimental results are listed in Table 2.

2

The highest oil sorption capacity had samples with 100% ash content. Thus, the degree of absorption increased during the first 30 minutes and did not increase after that, indicating occurrence of adsorption equilibrium. After the occurrence of the saturation point, the samples containing ash in an amount of 100% and 75% lost their original shape due to swelling and breaking bonds between the precursor particles. In order to evaluate the retention capacity, the re-weighting of samples containing 0-50% ash after 5 hours of aging in an upright state was performed. The loss in weight was less than 0.01% that indicates a high retention capacity of obtained adsorbents.

With the increase in the sludge percentage in the composite, the oil sorption capacity decreased (Fig. 2). This is because the sludge is more susceptible for pressing and this, which ultimately affects the value of the effective surface of the composite material. Oil sorption rate also depended on the composition of the material (Fig. 3).

Table

The averaged values of water sorption capacity during time, %

Time (t), sec Sludge (S) 100% Composite material Ash (A) 100%

S (75%) +A (25%) S (50%) +A (50%) S (25%) +A (75%)

Water sorption capacity after time t, % 0 0,00 0,00 0,00 0,00 0,00

15 3,28 8,94 14,68 15,32 22,86

30 5,16 11,22 21,26 24,88 38,31

45 7,66 16,30 25,08 31,40 43,29

60 9,87 20,82 26,29 37,50 44,36

90 11,91 23,62 27,38 38,23 46,24

120 13,16 25,77 28,34 38,97 46,65

Amount of sludge, %

Fig. 2. The dependence of the oil sorption capacity on the composition of the material.

S - Sludge

£

n

cl

q

v ¡2

O

o

i/1

— S (100%)

---S (75%) + A (25%}

-•-S (50%) + A (50%) -•-S (25%) + A (75%)

— A (100%)

A - Ash

1 i 1 i 1 i ' i ■ i 1 i 1 i 1 i ■ i 1 i ■ i 1 i ■ i 1 I 1 i 1 i ■

(1 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

Amount of sludge, %

Fig.3. The change in the sorption rate over time depending on the composition of the material.

For all investigated samples maximum of sorption rate sorbent for cleaning oily waste and spills of oils. is reached after four minutes of samples location on the oil - composite material should contain at least 30% of

surface. After that the sorption rate drops significantly. With sludge to achieve strength characteristics (to prevent possible

the increase in a sludge percentage in the composite material, particulate of sorbent) and to increase the time spent in the

oil sorption rate decreases. The maximum of sorption rate is water by reducing the wettability;

shifted to the right on the timeline. This is due to lower sludge - composite material should contain at least 25% of the ash

towards ash porosity. to increase the sorption capacity and sorption rate.

The results obtained allow to highlight a number of practical Using mathematical modeling method the composition

recommendations for the developing of laboratory sample of of composite material having an optimal characteristics was

the composite material based on sludge and ash for its use as a found (Fig. 4).

JjOn

1.5-

1.6-

M

* *

d 1,0-

<

= 0»B-

0,40,2-

0,(1 -I-r-1-1-'-1-1-1-1-i-'-1—

0 20 41) ¿0 80 10(1

Amount fltf sliiil^-e in the composite, %

•— Oil sorption capacity *—Water sorption capacity

Fig.4. The change of oil and water sorption parameters of the composite material, depending on its composition

The intersection point of the logarithmic lines reflects the composition of the developed material having the best combination of sorption characteristics: 48% of sludge and 52% of ash.

The parameters of the composite material were found:

- water capacity - 26.9%;

- sorption capacity for oil - 14.7%;

- maximum sorption rate of - 2.1%/min.

Thus, pre-treatment of the sludge additives, as well as the modeling of the composition of the sorption material allowed to increase oil sorption capacity and also to reduce the time needed for oil sorption in comparison to existing analogues [1]. The developed composite material based on sludge and ash waste of TPSs can be used as a sorbent [13] for the removal of

oil spills and as an alternative fuel.

The developed sorbent consists of calcium carbonate (48%), so we suggest to make modifications using polymethilhydridsilocsane solution (94M-NGL) with subsequent heat treatment to make composite hydrophobic [14].

Thus, a new composite material based on sludge and ash from TPSs was developed and it was shown that it can be used as a sorbent for cleaning oily waste and spills of oils from the surface of water thereby reducing the anthropogenic load of industrial enterprises on the environment [15].

Acknowledgements. The presented work was supported by FASIE (grant №0011756) and IVF RT (grant №0002141).

References:

1. L. A. Nikolaeva, E. N. Boroday. Resource saving technology of water treatment sludge disposal at TPSs. Monograph. -Kazan: Kazan state power engineering university. - 2012. - 138 p.

2. GOST 12536-79. Methods of laboratory determination of granulometric (grain) and microaggregate composition.

3. Methods for disposal of chemical water treatment sludge of thermal power plants: X Korsakovsk International meeting on physical-chemical analysis / Samara: Samar. state technical. univ. Vol. 2. - . 2013. - 332 p.

4. Protocol No. 172/Waste from 15.12.2013 «Analytical study of waste composition: the results of sludge composition studies».

5. Nikolaeva L.A., Laptev A.G., Mikhailova G.A. The use of sludge clarifiers TPS as a filler in the technology of rubber and rubber goods / Proceedings of the higher educational institutions. Energy problems. - 2008. - №5-6. - 129 p.

6. Barieva E.R., Korolev E.A., Egorova E.S. Modeling ceramic batch composition using slag waste of Kazan CHP-2 / Proceedings of the higher educational institutions. Energy problems. - 2009. - №7-8. - 157 p.

7. Scazlich M., Roskovi R., Banjad Pelur I. Properties of SCC with high fly ash content / Gradjevinar. - 2008. - Vol.11. - P. 945-952.

8. Kozlova V.K., Manoha A.M., Likhosherstov A.A., Manuilov E.V., Malova E.J. The influence carbonate additives on properties of composite cements / Cement and its application. -2012. Vol. 3. - P. 25-29.

9. Timashev V.V., Kolbasov V.M. Properties of carbonate cements with additives /

Cement. - 1981. - Vol. 10. - P. 10-13.

10. Khantimerova Y.M., Barieva E.R. Methods to reduce the environmental load on the environment by using recycled sludge waste / Materials of the VI International Youth Scientific Conference «Scientific potential of the XXI century». Vol. 1. Natural and Technical Sciences. - Stavropol: NCSTU. - 2012.

- 134 p.

11. R.R. Khusainov, R.V. Bolshakov. Prospective directions of use of slag of TPSs / Ecology of manufacturing. - 2009. - Vol. 12. - P. 56-61.

12. GOST 23314-91 «Determination of moisture content of fuel».

14. Nikolaeva L.A., Nedzvetskaya R.Ya. Water: chemistry and ecology. - 2012. - Vol.8. - p.80-84.

14. Patent No. 2447935 Russia / Nikolaeva L. A., Golub chikov M. A. A method of producing hydrophobic adsorbent for cleaning natural waters and sewage from oil products.

15. Krivenko T.I., Bamburov V.G. Physical-chemical model of optimization of the environment in the industrial zone of thermal power stations / Chemical technology. -2010. - Vol. 6.

- p. 380 - 383.