Title of Invention

A PROCESS FOR THE MANUFACTURE OF ACTIVE CARBON FROM COKE BREEZE

Abstract

This invention describes a process for the manufacture of active carbon from coke breeze in a fluid bed reactor, pre-heated at 600 degree Celsius, allowing the temperature of the reactor, containing crushed and screened coke breeze, to rise steadily to 900 degree Celsius, injecting superheated steam from below the reactor, allowing the carbon materials to remain in a fluidized state for a time period in the range of 1 to 2 hours. After the activation period is over, the reactor is allowed to cool down to 350 degree Celsius. The product is discharged after adjusting the pH between 6.5-7.0 by known methods. The active carbon so obtained is useful for removing toxicants from effluent water from coke plants 13

Full Text

The present invention relates to a process for the manufacture of active carbon from coke breeze. This invention particularly relates to preparation of highly porous, relatively dense active carbon from comparatively cheap raw material like coke breeze, abundantly available from coke oven plants, for removal of toxicants from effluent water of coke plants. This invention finds its usage in removing toxicants from effluent water from coke oven plants. In this invention, active carbon obtained from relatively cheap raw materials like coke breeze, which is abundantly available from coke oven plants, is used and at the same time environmental pollution hazard is controlled unlike other conventional raw materials and impregnation methods. High quality activated carbon is required for decolourising purposes in sugar industry, oil industry, alcoholic beverages, pharmaceutical indusl Itry and for gas & vapour adsorbing purposes in gas mask industry and environmental pollution control measures and in recent times for industrial waste water treatment purposes as well as in the processing of drinking water. Indian cokeries produce significant amount of coke breeze. The use of coke breeze is very limited. It is used in sintering as well as for the production of briquettes. Coke producing industry is facing acute problems for marketing the coke breeze. The market demand for coke breeze in India is 1,35,000 metric tons against present installed capacity of 75000 metric tons. In recent times, active carbon is being used for removal of toxic organic substances from mine water, waste water etc. While conventional waste water treatment methods, such as ion exchanges, reverse osmosis, chemical oxidation, precipitation and gas tripping are effective in removing toxicants, application of granular activated carbon has good scope, particularly in areas like regeneration, more efficient and low cost technology, adsorbate recovery and reuse and prediction of application in waste water treatment. In view of acute shortage of drinking water supply in rural and urban areas and constant pollution of surface water by discharge of toxic industrial effluents, the present process is amply relevant and justified. partitioning volatile organic contaminants between a liquid phase and a gas phase. In yet a further embodiment, the above versions of the invention are simultaneously performed in the same reaction vessel. In the above prior art processes, active carbon from coke breeze was not used. Coke breeze, a waste material, was unused for the purpose of manufacturing active carbon, useful for removal of toxicants from effluent water. The main object of the invention is to provide a process for the manufacture of active carbon from coke breeze, useful for removal of toxicants from effluent water of coke plants which obviates the drawbacks as detailed above. Another object of the invention is to prepare a highly porous, relatively dense active carbon from comparatively cheap raw material like coke breeze, abundantly available from coke oven plants, for removal of toxicants from effluent water of coke plants. Still another object of the invention is to provide pollution free process for preparation of active carbon from coke breeze. This invention describes a process for the manufacture of active carbon from coke breeze in a fluid bed reactor, pre-heated at 600 degree Celsius, allowing the temperature of the reactor, containing crushed and screened coke breeze, to rise steadily to 900 degree Celsius, injecting superheated steam from below the reactor, allowing the carbon materials to remain in a fluidised state for a time period in the range of 1 to 2 hours. After the activation period is over, the reactor is allowed to cool down to 350 degree Celsius. The product is discharged after adjusting the pH between 6.5-7.0 by known methods. The active carbon so obtained is useful for removing toxicants from effluent water from coke plants Accordingly the present invention provides a process for the manufacture of active carbon, which comprises (a) crushing coke breeze to -6+14 BSS size in a crusher; (b) charging the screened material into a fluid bed reactor, preheated at 600 degree Celsius; (c) allowing the temperature of the reactor to rise steadily till it reaches 900 degree Celsius; (d) injecting superheated steam from below the reactor; (e) allowing the carbon materials to remain in a fluidised state for a time period in the range of 1 to 2 hours, maintaining the temperature of the reactor at a temperature in the range of 900 to 920 degree Celsius; (f) after the activation period is over, allowing the reactor temperature to cool till the temperature comes down to 350 degree Celsius and discharging the product after adjusting the pH between 6.5-7.0 by known methods. In an embodiment of the present invention the reactor is cooled by quenching by ice. The novelty of the present invention resides with obtaining active carbon from coke breeze, under environment friendly conditions in comparison to available prior art, for removing toxicants from effluent water of coke plants, which was other wise was not utilised for economic reasons by this process active carbon is obtained from a waste product such as coke breeze and the active carbon so obtained can be used for converting waste water into potable water. The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. Example-1 160 grams of coke breeze was crushed and sized to -6+14 BSS. The screened material was then charged into a fluid bed reactor, which was pre-heated to 600 degree Celsius. The temperature of the reactor was allowed to increase steadily to 900 degree Celsius, after which superheated steam was injected from below the reactor and carbon materials were allowed to remain in fluidised state for one hour. After the activation period was over, the reactor temperature was cooled down by steam quenching till the reactor temperature reaches 350 degree Celsius. The product was taken out and pH was adjusted to 6.7. The yield was 78%. The product was used for effluent water purification. Analysis of coke plant effluent before and after treatment with active carbon obtained from coke breeze: Parameters Analysed Phenol Oil & Grease Iron Concentration in the effluent before treatment (ppm) 1037.5 326.0 5.0 Concentration in the effluent after treatment (ppm) 37.0 22.8 Below detectable limit % Removal 96.43 93.0 100.0 Example-2 160 grams of coke breeze was crushed and sized to -6 to +14 BSS. The screened material was then charged into a fluid bed reactor, which was pre-heated to 600 degree Celsius. The temperature of the reactor was allowed to increase steadily to 900 degree Celsius, after which superheated steam was injected from below the reactor and carbon materials were allowed to remain in fluidised state for one and half hours. After the activation period was over, the reactor temperature was cooled down by steam quenching till the reactor temperature reaches 350 degree Celsius. The product was taken out and pH was adjusted to 6.8. The yield was 63%. The product was used for effluent water purification. Analysis of coke plant effluent before and after treatment with active carbon obtained from coke breeze: Parameters anlysed Phenol Oil & Grease Iron Concentration in the effluent before treatment (ppm) 1013.12 359.0 5.8 Concentration in the effluent after treatment (ppm) 30.19 10.0 0.1 % Removal 97.02 97.21 98.28 Example-3 160 grams of coke breeze was crushed and sized to -6 to +14 BSS. The screened material was then charged into a fluid bed reactor, which was pre-heated to 600 degree Celsius. The temperature of the reactor was allowed to increase steadily to 900 degree Celsius, after which superheated steam was injected from below the reactor and carbon materials were allowed to remain in fluidised state for two hours. After the activation period was over, the reactor temperature was cooled down by steam quenching till the reactor temperature reaches 350 degree Celsius. The product was taken out and pH was adjusted to 6.8. The yield was 59%. The product was used for effluent water purification. Parameters analysed Phenol Oil & Grease Iron Concentration in the effluent before treatment ( ppm) 897.91 413.0 4.6 Concentration in the effluent after treatment ( ppm) 13.33 8.20 0.1 % Removal 98.52 98.01 97.83 Typical Results and evaluation characteristics of the products of the different examples cited Table-1 Adsorption Qualities Methylene Blue Adsorption (mg/g) Iodine Adsorption (mg/g) Phenol Adsorption(%) Example- 1 (one hour) 38.4 226.96 99.9 Example-2 (one & half hours) 37.0 220.83 99.8 Example-3 (two hours) 38.4 220.82 99.34 Table-2 Other characteristics pH value Bulk density(kg/ltr) Moisture(%) Ash(%) Volatile Matter (%) Fixed Carbon(%) Example- 1 6.7 0.64 1.7 15.2 1.3 81.8 Example-2 6.8 0.49 1.5 16.8 1.0 80.7 Example-3 6.8 0.48 - -- - 10 The main advantages of the present invention are: 1. The adsorbate can be removed from liquid streams without significant expenditure. 2. The raw material is easily available from coke oven industries and at comparatively cheaper price. 3. The yield of product is much higher than any other raw materials. 4. Conventional chemical impregnation step can be avoided, there by pollution is controlled. 5. Since active carbon obtained from the process is highly porous, degradation of particles during handling is much less. We claim: 1. A process for the manufacture of active carbon from coke breeze, which comprises the steps of: a. crushing coke breeze to -6 to +14 British Standard Sieve (BSS) in a crusher to screen the material; b. charging the screened material as obtained in step (a) into a fluid bed reactor which has been preheated to 600 degree Celsius; c. allowing the temperature to rise steadily till it reaches 900 degree Celsius; d. injecting superheated steam from below the reactor; e. allowing the carbon materials to remain in a fluidized state for a time period in the range of 1 to 2 hours, maintaining the temperature in the range of 900 to 920 degree Celsius; f. allowing the reactor temperature to cool till the temperature comes down to 350 degree Celsius and discharging the product after adjusting the pH between 6.5 to 7. 2. A process as claimed in claim 1, wherein the reactor is cooled by quenching with ice.

Documents:

334-DEL-2002-Abstract-(17-10-2008).pdf

334-del-2002-abstract.pdf

334-DEL-2002-Claims-(17-10-2008).pdf

334-del-2002-claims.pdf

334-DEL-2002-Correspondence-Others-(17-10-2008).pdf

334-del-2002-correspondence-others.pdf

334-del-2002-correspondence-po.pdf

334-DEL-2002-Description (Complete)-(17-10-2008).pdf

334-del-2002-description (complete).pdf

334-DEL-2002-Form-1-(17-10-2008).pdf

334-del-2002-form-1.pdf

334-DEL-2002-Form-18-(17-10-2008).pdf

334-del-2002-form-18.pdf

334-DEL-2002-Form-2-(17-10-2008).pdf

334-del-2002-form-2.pdf

334-del-2002-form-3.pdf