KR20100021681A - Manufacture technicque of chemical impregnated pelletized activated carbon for the removal of odorous gases from food waste - Google Patents

Abstract

PURPOSE: A technique for manufacturing complex impregnation pelletized activated carbon for removing bad smell gas of food waste is provided to eliminate adsorbate molecules of the small size and adsorbate molecules of the big size by using coconut shell activated carbon in which the mean polishing size is 20Å and 100Å coal-based activated carbon. CONSTITUTION: A technique for manufacturing complex impregnation pelletized activated carbon comprises: a step of molding and mixing the pelletized activated carbon in a mixing ratio of CaCO 3(1.6Wt%), bunker-oil, creosote oil(antiseptic,5.1Wt%), lignin sodium sulfonate(a dispersing agent, and 1.9Wt%), and assembly water(12.3Wt%) by using coal tar pitch as a bonding agent; a step of carbonizing molded complex pelletized activated carbon for 2 hours at 450°C and in chemical activating for 2hr ~ 4hr at 850°C by using an activating oven of nitrogen atmosphere; and a step of manufacturing the complex impregnation pelletized activated carbon for removal of acid gas which is dipped in 5Wt% of potassium hydroxide(KOH) aqueous solution and the complex impregnation pelletized activated carbon for removal of basic gas which is dipped in 5v / v% of phosphoric acid(H3PO4) aqueous solution.

Description

Manufacture technicque of chemical impregnated pelletized activated carbon for the removal of odorous gases from food waste}

The present invention relates to a technology for manufacturing complex impregnated activated carbon for removing odor gas from food wastes, by finely pulverizing coal-based activated carbon and coconut shell activated carbon, which have been conventionally used, in order to increase the removal rate of malodorous gas having various molecular sizes. After mixing, it is re-molded to produce a composite granulated activated carbon. Here, it is about the selection of chemicals and the concentration of impregnation, which are suitable for the production of activated carbon which can effectively remove all the acid gas, neutral gas and basic gas.

In recent years, there have been many difficulties in terms of odor complaints and the environment. In addition to industrial complexes, facilities located near living, such as livestock barns, food resource-recycling facilities, and the like, and in recent years, disposal of food waste at homes has become a big problem.

In Korea, the variety of foods is traditionally diverse, and the amount of food is considered a virtue, and the amount of food waste is much higher than that of other countries. Korea's daily waste generation amounted to 48,398 tons in 2005, with food waste consisting of 38.5%. In addition, the amount of food waste generated annually is increasing by 11,398 tons / day in 2003, 11,464 tons / day in 2004 and 13,028 tons / day in 2005.

The size of micropores effective for adsorption is about 3 to 6 times that of adsorbate molecules. Because this difference is reduced, the diffusion resistance increases by molecular sieve action. Since the average pore size of coconut shell activated carbon is 20 μs, the size of adsorbate molecules to be adsorbed here should be 3 to 7 μm. It should be 33Å. However, at present, without considering the size of these adsorbate molecules, coconut shell activated carbon and coal-based activated carbon are arbitrarily used.

The present invention can not be effective removal of odor gas during the disposal of food waste by landfill, incineration, recycling, etc., which is considered as a hate facility or evacuation, and the average pore size to solve the current situation that is recognized as the main culprit of environmental pollution. Cobalt activated carbon of 20Å and coal-based activated carbon of 100Å are used to prepare complex activated carbon that can remove small sized adsorbate molecules and large sized adsorbate molecules, and attach appropriate chemicals to them. The purpose of the present invention is to prepare a composite impregnated activated carbon having improved adsorption capacity by using chemical adsorption power as well as physical adsorption power of activated carbon.

In fact, the results from many experiments showed that the basic gas of trimethylamine (109.6 to 138.7 ppm) was significantly higher than that of 1.6 ppm to 3.9 ppm of methyl mercaptan, which is the total acid gas generated when treating 1,000 g of food waste. , peak concentration was 2.4 ppm of trimethylamine, and 16 times of 0.15 ppm of methyl mercaptan was detected. According to the present invention, when a mixture of coconut shell activated carbon having an average pore size of 20 kPa and coal-based activated carbon having 100 kPa is used, the adsorbent molecules have a size of 3 to 7 kPa and small molecules and 16 to 33 kPa can be effectively removed. do.

In addition, since the physical adsorption power of the general activated carbon alone cannot remove many malodorous gases, it is impregnated with alkaline aqueous solution of KOH to remove acid gas, and impregnated with acidic aqueous solution of H ₃ PO ₄ to remove basic gas. If adsorbed, the adsorption capacity of the activated carbon is slightly reduced to about 90%. However, if the activated carbon having a suitable pore is selected, the adsorbent having both excellent adsorption of activated carbon and reactivity of chemicals can be prepared.

Activated carbon in the composite-impregnated granules of the present invention is methyl mercaptan and hydrogen sulfide among acid gases with low odor intensity but strong odor intensity generated during disposal of food waste, and high concentrations of ammonia and trimethyl As a result of testing the ability to remove various odorous gases from amines, acid gas showed adsorption capacity of 20 times compared to general activated carbon, basic gas showed adsorption capacity of about 7 to 10 times, and activated carbon on coal-based impregnated granules. Compared with the adsorption capacity of about 40% was shown. The present invention manufactured by the above method is capable of excellent performance even when used as a food waste processor filter, which has been turned into a water-treatment complex due to lack of performance in general homes such as food waste incineration facilities or food resource recycling facilities. I will do it.

The present invention consists of an acidic aqueous solution of H ₃ PO ₄ , an alkaline aqueous solution of KOH, and a composite granulated activated carbon re-formed by mixing coal-based powdered activated carbon and coconut shell powdered activated carbon, and a dryer capable of drying the composite granulated activated carbon ( 115 ± 5 ° C.) and carbonization under 400 ° C. and a test furnace which can be activated between 900 ° C. and 1,100 ° C. were used. For the real test, 10 kinds of typical foods that are most discharged from homes and restaurants and generate bad odor gas were selected and mixed according to the blending ratio, and then the samples were decayed for a certain time. The odor (EF-20), a food waste disposal system of Ecopoyu Co., Ltd., which conducted a joint experiment, was crushed and dried, and the amount of odor gas generated during treatment and the present invention were installed as a filter and discharged during treatment. Residual odor gas was measured and the removal capacity was tested.

For more accurate comparison of odor gas adsorption capacity test, 501ppm Trimethyl amine gas ((CH ₃ ) ₃ N, N ₂ Balance), U-pipe, flow meter, etc. The detection tube which can detect the low density | concentration of a unit was used.

Example 1

For the production of prototypes, Coconut activated carbon with 20Å of Mirco pore, and coal powder activated carbon with 20 ~ 100Å of fine pores and medium pores were mixed in various ratios (see comparison of pore shape in Table 1) . Coal tar pitch (oil content at 230-300 ℃) was used as caking agent by weight ratio 0.4-0.55, and they were pulverized sufficiently to 200mesh or less to increase the mechanical strength of the granulated coal. Other components include K ₂ CO ₃ , CaCO ₃ (1.6Wt%) and Bunker-Oil or Creosote Oil (preservative, 5.1Wt%) and Lignin Sodium Sulfonate (dispersant, 1.9Wt%) and granulated water (12.3) Wt%) was used to facilitate aggregation between raw materials.

The molded composite granulated activated carbon was dried at 115 ± 5 ° C. for 4 hours in a dry oven, and then carbonized for 2 hours at a heating rate of 5 ° C./min from 450 ° C. to 450 ° C. in an activated nitrogen atmosphere. It was cooled after 2hr to 4hr chemical activation (KOH).

As a result, the specific surface area of the coconut shell powder activated carbon was 1,355 m 2 / gAC, the coal powder activated carbon 1,527 m 2 / gAC, and an average of 1,441 m 2 / g AC, which was increased by 1,637 m 2 / gAC to 1,637 m 2 / gAC when reformed with the composite granular activated carbon.

Table 1. Pore shape comparison of coconut shell activated carbon and coal activated carbon

Example 2

Activated carbons used in conventional food waste treatment are based on 'physical adsorption', which is temporarily captured by Van Der Waals and Coulomb Force (heat of adsorption 10-15 kcal / mol) between adsorbent (AC) surface and adsorbate (simple molecular gas). Although it has been used, since it can be easily desorbed and regenerated even by environment or temperature changes, it is difficult to effectively remove the odorous gases that are reversible and polar molecules. On the other hand, complex impregnated activated carbon was prepared by irreversible secondary chemical reactions involving electron transfer and heat of adsorption of 10 to 30 kcal / mol, that is, 'chemical adsorption' by the deposition of various chemicals. (See Table 2)

In the production of composite impregnated activated carbon for acid gas removal, impregnated with an aqueous solution of strong basic caustic soda (NaOH) and potassium hydroxide (KOH) as an aqueous solution at a ratio of 5 to 10 wt% for about 3 hours, and then dried in an 80 Prepared by drying to ± 5 ° C. The pH of this invention was uniformly measured to be more than 10.0 by 'KS M 1802', an activated carbon test method. This invention product was tested for the removal of acidic gas, methyl mercaptan (CH ₃ SH), and the concentration of odor gas detected before and after the filter was prepared "Gastech detector" and detection tube No. 71 (measurable range 0.1ppm to 140 ppm) was not detected at all.

In the production of the composite impregnated activated carbon for basic gas removal, impregnated with an opposite polarity of hydrochloric acid (HCl) and phosphoric acid (H ₃ PO ₄ ) in an aqueous solution of ₅ to 10v / v% for about 3 hours, followed by drying in a dry oven. It was prepared by drying at 115 ± 5 ℃, the pH was uniformly measured to less than 3.0 as a result of the same method. In the basic gas removal experiment, ammonia (NH ₃ ) was measured using detection tube No. 3L (measurable range: 0.2 to 60 ppm) and trimethylamine ((CH ₃ ) ₃ N) with detection tube No. 180 (0.35 ppm to 70 ppm). As a result, it was not detected at all.

Table 2. Comparison of General Activated Carbon and Impregnated Activated Carbon

Example 3

According to the information announced by the Ministry of Environment, 10 kinds of representative foods with high food waste generation rate and high odor gas were selected and mixed according to the mixing ratio, and the decayed foods were used as standard samples for a certain time. This standard sample is crushed and dried by Ecopoyu Co., Ltd., Food Waste Disposal Machine 'EF-20' to determine the gas concentration and total amount of methyl mercaptan (CH ₃ SH) produced during processing. The average gas concentration was measured by dividing by the treatment time. In addition, it was tested that residual odor gas discharged from the filter could be effectively removed, and the experiments were conducted with varying the throughput of standard sample and the decay progress time at room temperature (25 ℃) for each experiment order. )

During the treatment, the gas generation concentration by time period decreased rapidly after reaching the peak at the beginning of 30 minutes of drying, and the generation amount was also smaller than that of the basic gas. At this time, the gas generation amount of methyl mercaptan (CH ₃ SH) decreased as the decay progressed, as opposed to the basic gas, and the gas detection amount after passing the filter filled with the present invention was "Zero ppm" (Table 3, See drawing 2)

Table 3. The amount of methyl mercaptan gas generated by the experimental order and the concentration before and after the filter pass

Example 4

In Example 3, the ammonia (NH ₃ ) gas was detected in the same manner as the method of measuring the amount of methyl mercaptan (CH ₃ SH) gas generated according to the food waste standard sample and the concentration before and after passing through the filter. As a result of measuring by 3L (measurable range: 0.2 ~ 60ppm), the gas generation concentration by treatment time decreased rapidly after reaching peak at 130 ~ 180 minutes during drying. As the decay progressed, the gas generation amount and concentration rapidly increased, but the gas detection amount after passing the filter showed "Zero ppm" as in the previous case (see Table 4 and Figure 3).

Table 4. Amount of Ammonia Gas Generated by Experimental Order and Concentration Before and After Filter Passing

Example 5

Trimethylamine ((CH ₃ ) ₃ N) gas was measured with detection tube No. 180 (measurable range: 0.2 to 60 ppm) in the same manner as in [Example 3] and [Example 4]. As with phosphorus ammonia (NH ₃ ) gas, the concentration of gas generated during treatment decreased rapidly after peaking at 150-180 minutes during drying. As the decay progressed, the gas generation amount and concentration rapidly increased, but the gas detection amount after passing the filter showed "Zero ppm" as in the previous case (see Table 5 and Figure 3).

Table 5. Trimethylamine Gas Generated by Experimental Order and Concentration Before and After Filter Passing

Example 6

To compare the odor gas adsorption capacity, trimethylamine ((CH ₃ ) ₃ N) pure standard gas (501 ppm), which is the basic gas having the highest amount and the highest gas concentration, was used. Composite impregnated activated carbon as an invention was tested using a prototype impregnated with 5v / v% phosphoric acid (H ₃ PO ₄ ) prepared in [Example 2]. Fill the U-tube (radius 1.8cm) with 9g of each prototype (drying standard), and pass through the pure standard gas (501ppm) at a flow rate of 1.14ℓ / min to adsorb it, and keep the airtight except the filter inlet and outlet. Make sure there is no gas. The experiment is terminated at the time when the breakthrough time of 1/10 (50.1ppm) of the input gas concentration of 501ppm is detected by detecting with the gas detector No.180 at the time of the filter exit. The amount of odor gas adsorbed by each prototype is calculated as the amount of (CH ₃ ) ₃ N adsorption (g- (CH ₃ ) ₃ N / g-AC) per 1g of activated carbon, based on the time of adsorption and the concentration of standard gas.

As a result, the breakthrough point of the activated carbon in the composite-impregnated granules was 630min, which was about 40% higher than the 450min of the coal-based impregnated activated carbon.

Example 7

Trimethylamine ((CH ₃ ) ₃ N) using a prototype impregnated with phosphoric acid (H ₃ PO ₄ ) impregnation concentration of 10 v / v% to the activated carbon in the composite impregnated granules in the same manner as in Experiment 6 The adsorption capacity of pure standard gas (501ppm) was compared.

As a result, the activated carbon having a breakthrough point of 470 min rather than phosphorus (H ₃ PO ₄ ) 5v / v% showed 34% higher adsorption performance.

The present invention can be effectively used for the removal of a specific single odor gas and a variety of complex odor gas even when processing a large amount of food from the general household food processing, the processed food waste is also possible to resources such as compost.

1 is a view showing a manufacturing process of the composite impregnated granular activated carbon.

2 is a generation concentration of methyl mercaptan gas with time at various conditions in the real experiment.

3 is a generation concentration of ammonia gas with time at various conditions in the real experiment.

4 is a generation concentration of trimethylamine gas with time at various conditions in the real experiment.

Claims (1)

In preparing the composite granular activated carbon, Coconut activated carbon and coal-based activated carbon were mixed, and then coal tar pitch was used as caking additive, and as a subsidiary material, CaCO ₃ (1.6Wt%) and Bunker-Oil or Creosote Oil (preservative, 5.1Wt%) and Lignin Sodium Sulfonate (dispersant) , 1.9 Wt%) and granulated water (12.3 Wt%) at a mixing ratio to form the activated carbon in the granulation phase, Carbonization of the molded composite granular activated carbon using an activation atmosphere of a nitrogen atmosphere at 450 ° C. for 2 hours and chemical activation at 850 ° C. for 2hr to 4hr, After the above step, the composite impregnated granular activated carbon for basic gas removal impregnated with 5v / v% aqueous solution of phosphoric acid (H ₃ PO ₄ ) and the complex impregnated granular activated carbon for acid gas removal impregnated in 5 Wt% aqueous solution of potassium hydroxide (KOH) were prepared. Steps to

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