CN1251965C - Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas - Google Patents
Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas Download PDFInfo
- Publication number
- CN1251965C CN1251965C CN 02137839 CN02137839A CN1251965C CN 1251965 C CN1251965 C CN 1251965C CN 02137839 CN02137839 CN 02137839 CN 02137839 A CN02137839 A CN 02137839A CN 1251965 C CN1251965 C CN 1251965C
- Authority
- CN
- China
- Prior art keywords
- gas
- sulfuric acid
- hydrogen sulfide
- sulfur trioxide
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Treating Waste Gases (AREA)
Abstract
The present invention belongs to the technical field of environmental protection, which is suitable for processing acidic gases containing hydrogen sulfide generated in synthetic ammonia industry, petrochemical industry, coking chemical industry, etc. After being burnt, cooled and defogged, the gases containing hydrogen sulfide enter a drying circulation system, and sulfuric acid is used for removing water; after being heated by a heat exchange device, furnace gases containing sulfur dioxide are converted for the first time in a conversion system to produce sulfur trioxide; after sulfuric acid absorbs the sulfur trioxide in the gases, the gases are converted for the second time to convert the sulfur dioxide into the sulfur trioxide as much as possible; then sulfuric acid is used again for absorbing the sulfur trioxide in the gases; finally, the gases reach the standards and are discharged; after the sulfur trioxide is absorbed, sulfuric acid is produced with a concentration of 78% to 110%. The present invention stops the pollution of hydrogen sulfide to environment, makes full use of hydrogen sulfide resources and has the characteristics of sufficient heat recovery, less corrosion in devices, continuous and stable technique, high safety and simple technique. The obtained sulfuric acid has the characteristics of high product quality, high concentration and wide application.
Description
The technical field is as follows: the invention belongs to the technical field of environmental protection, and particularly relates to a method for preparing high-concentration sulfuric acid by utilizing acid gas containing hydrogen sulfide.
Background art: the techniques related to the present invention are:
CN1163858, a process for recovering sulfur from gas containing hydrogen sulfide, which recovers hydrogen sulfide into sulfur, and the present technology has the following three problems: a. the tail gas emission does not reach the standard. b. The running cost is high. c. The investment of the device is large.
CN1077433, condensation of sulfuric acid production to acid process, the present technology has the following problems: a. the equipment is severely corroded. b. The wet conversion acid production part only adopts one-to-one absorption, the sulfur utilization rate is low, a tail gas absorption device is required, otherwise the environmental protection requirement cannot be met, the concentration of the prepared acid product is limited, and the general acid concentration cannot exceed 97 percent.
CN1339400A, the acid gas containing hydrogen sulfide is combined with sulfur to prepare high-concentration sulfuric acid, the sulfur and hydrogen sulfide are used together to prepare high-concentration sulfuric acid in the process, the investment is high, and the process is complex.
The invention content is as follows: the invention aims to provide a method for treating acid gas containing hydrogen sulfide generated in the industries of synthetic ammonia industry, petrochemical industry, coking chemical industry and the like to produce high-concentration sulfuric acid and eliminate environmental pollution.
The invention is realized by the following steps:
1. burning, cooling, removing acid mist and drying the acid gas containing hydrogen sulfideAnd (4) sequencing. When the blower is used for exhausting air, the hydrogen sulfide combustion furnace is operated at negative pressure, the acid gas containing hydrogen sulfide is fed into the combustion furnace and combusted together with air in the combustion furnace, the combustion temperature is controlled at 500-1300 ℃, and the acid gas is passed through a heat exchange deviceCooling to 150-600 deg.C, humidifying, cooling, demisting, etc., removing 20-100% of acid mist, introducing the flue gas containing water vapor into a washing tower, further cooling and demisting, introducing into an electric demister at 10-60 deg.C, introducing the demisted gas and air (or oxygen-enriched gas) into a drying circulation system to make the water content in the gas discharged from the drying tower less than 1g/Nm3. Part of 1-70% dilute sulfuric acid generated in the humidifying, cooling and demisting processes is removed to an absorption system, and the rest is used as a by-product or a water removal treatment neutralization device.
2. Conversion and absorption procedure
The gas from the drying circulating system enters a converter of a conversion system after being preheated to a certain temperature by heat exchange equipment, most of sulfur dioxide in the process gas is converted into sulfur trioxide through first conversion, the sulfur trioxide in the process gas is absorbed by sulfuric acid, and then the process gas is preheated to a certain temperature by the heat exchange equipment and enters the converter for secondary conversion, and the sulfur trioxide in the process gas is absorbed by the sulfuric acid again. The sulfur trioxide in the process gas is absorbed to generate a sulfuric acid product with high concentration and good quality. And the content of SO2 in the finally discharged tail gas is low, and the tail gas reaches the national GB16297-1996 emission standard.
The invention has the following characteristics when treating the acid gas containing hydrogen sulfide: a. the acid making part can adopt a two-conversion two-absorption process, the sulfur utilization rate is high, the environment-friendly requirement can be met without adopting a tail gas absorption device, and the concentration of the prepared acid product is 78-110%. b. The operation cost is low. c. The investment of the device is small. d. The operation is simple. e. The corrosion of the equipment is not serious.
The flow is illustrated as follows:
when the acid gas containing hydrogen sulfide produced in the synthetic ammonia industry, the petrochemical industry, the coking chemical industry and other industries is exhausted by a main blower, the hydrogen sulfide in a hydrogen sulfide combustion furnace is operated under negative pressure, the hydrogen sulfide enters the combustion furnace and is combusted together with air in the combustion furnace, the combustion temperature is controlled to be 500-1300 ℃, the temperature is reduced to 150-500 ℃ by a heat exchange device, the hydrogen sulfide enters a heat insulation, humidification and cooling device to remove 30-100% of acid mist, the process gas containing saturated steam enters a washing tower, the temperature is further reduced and demisted, the process gas enters an electric demister at 10-60 ℃, and the demisted gas enters a drying and circulating system.
The main reaction is as follows:
The process gas from the heat exchange equipment enters a conversion system at 350-500 ℃, 60-97% of sulfur dioxide in the process gas is converted into sulfur trioxide through first conversion, the sulfur trioxide in the process gas is absorbed by sulfuric acid, the process gas is preheated to 350-500 ℃ through the heat exchange equipment and then enters the conversion system again for secondary conversion, and then the sulfuric acid is used for absorbing the sulfur trioxide in the process gas. The sulfur trioxide in the process gas is absorbed to generate a sulfuric acid product with the concentration as high as 78-110%. And the content of SO2 in the finally discharged tail gas is low, and the emission standard of GB16297-1996 is met.
The main reaction is as follows:
The invention not only puts an end to the environmental pollution caused by hydrogen sulfide, but also makes full use of hydrogen sulfide resources, and has the advantages of full heat recovery, small equipment corrosivity, continuous and stable process and good safety. The obtained sulfuric acid product has good quality, high concentration and wide application. The method for treating the hydrogen sulfide is a green and environment-friendly process.
The specific implementation mode is as follows:
example (b): the acid gas containing hydrogen sulfide generated in the coal coking process comprises the following gas components: h2S 32％；CO265％；N23% and gas content 6300Nm3H is used as the reference value. When the main blower is used for exhausting air, the hydrogen sulfide combustion furnace is operated at negative pressure, and acid gas containing hydrogen sulfide enters the combustion furnace and is mixed with airThe gas is combusted in a combustion furnace, is cooled by heat exchange equipment, enters humidifying and cooling equipment, 50% of acid mist is removed, the flue gas containing saturated steam enters a washing tower for further cooling and demisting, enters an electric demister at 25-60 ℃, and the demisted gas and a certain amount of air enter a drying and circulating system.
The process gas from the drying circulating system enters a conversion system after being preheated by heat exchange equipment, 80-97% of sulfur dioxide in the process gas is converted into sulfur trioxide through first conversion, the sulfur trioxide in the process gas is absorbed by 93-110% sulfuric acid, the process gas is preheated to a temperature higher than the ignition temperature of a catalyst, enters the conversion system again for secondary conversion, and then absorbs the sulfur trioxide in the process gas by 93-110% sulfuric acid. Sulfur trioxide in the process gas is absorbed to generate 93-110% sulfuric acid products, and the yield is 8.5-9 t/h. SO in the finally discharged tail gas2The content is low, and reaches GB16297-1996 emission standard.
Claims (4)
1. The method for preparing high-concentration sulfuric acid by utilizing the acid gas containing hydrogen sulfide is characterized by mainly comprising the following process flow steps:
① burning hydrogen sulfide in a combustion furnace, controlling the combustion temperature at 500-1300 deg.C, transferring heat, humidifying, cooling, demisting, and then feeding the burned gas and air or oxygen-enriched gas into a drying circulation system to remove water;
②, the gas after moisture removal enters a conversion system after heat exchange through heat exchange equipment, 60-97% of sulfur dioxide in the process gas is converted into sulfur trioxide, the sulfur trioxide in the gas is absorbed by sulfuric acid in a first absorption circulating system, the gas is subjected to heat exchange through the heat exchange equipment and then enters the conversion system for secondary conversion, the sulfur dioxide is converted into sulfur trioxide, the sulfur trioxide in the gas is absorbed by the sulfuric acid in a second absorption circulating system, and then the gas is discharged after reaching the standard;
③ the sulfur trioxide is absorbed to produce a high concentration of sulfuric acid.
2. A process for producing sulfuric acid having a high concentration by using an acid gas containing hydrogen sulfide as defined in claim 1, wherein said process comprises the step of ① burning the acid gas containing hydrogen sulfide with air in a hydrogen sulfide burner to produce a high temperature flue gas containing sulfur dioxide at a temperature of 500 ℃ to 1300 ℃, transferring heat and cooling the high temperature flue gas to a temperature of 150 ℃ to 600 ℃ by using a heat exchange device, humidifying, transferring heat and removing acid mist from the flue gas, and introducing the flue gas and the air or oxygen-enriched air into a drying cycle.
3. The method for preparing high-concentration sulfuric acid by using the acidic gas containing hydrogen sulfide as claimed in claim 1, wherein the sulfur dioxide-containing gas dried in the drying cycle system in the process step ② is heated by a heat exchange device and then enters a conversion system, 80-97% of sulfur dioxide in the process gas is converted into sulfur trioxide, the sulfur trioxide in the gas is absorbed by sulfuric acid in the first absorption cycle system, the gas is subjected to heat exchange by the heat exchange device and then enters the conversion system for secondary conversion, the sulfur dioxide is converted into sulfur trioxide, the sulfur trioxide in the gas is absorbed by sulfuric acid in the second absorption cycle system, and then the gas reaches the standard and is discharged.
4. The process for producing high-concentration sulfuric acid from an acid gas containing hydrogen sulfide as claimed in claim 1, wherein the concentrated sulfuric acid in process step ③ absorbs sulfur trioxide in the converted process gas to produce high-concentration sulfuric acid having a concentration of 78% to 110%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02137839 CN1251965C (en) | 2002-06-25 | 2002-06-25 | Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02137839 CN1251965C (en) | 2002-06-25 | 2002-06-25 | Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1385364A CN1385364A (en) | 2002-12-18 |
| CN1251965C true CN1251965C (en) | 2006-04-19 |
Family
ID=4749138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 02137839 Expired - Fee Related CN1251965C (en) | 2002-06-25 | 2002-06-25 | Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1251965C (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102743956A (en) * | 2012-07-25 | 2012-10-24 | 南京博图硫酸技术设计中心 | Process for preparing sulfuric acid by using regenerative gas obtained from active coke desulphurization |
| US9370745B2 (en) | 2013-04-24 | 2016-06-21 | Jiangsu New Century Jiangnan Environmental Protection Co., Ltd | Flue gas-treating method and apparatus for treating acidic tail gas by using ammonia process |
| US10016721B1 (en) | 2017-05-25 | 2018-07-10 | Jiangnan Environmental Protection Group Inc. | Ammonia-based desufurization process and apparatus |
| US10092877B1 (en) | 2017-05-25 | 2018-10-09 | Jiangnan Environmental Protection Group Inc. | Dust removal and desulfurization of FCC exhaust gas |
| US10112145B1 (en) | 2017-09-07 | 2018-10-30 | Jiangnan Environmental Protection Group Inc. | Method for controlling aerosol production during absorption in ammonia desulfurization |
| US10159929B1 (en) | 2017-06-14 | 2018-12-25 | Jiangnan Environmental Protection Group Inc. | Ammonia-adding system for ammonia-based desulfurization device |
| US20190001267A1 (en) | 2017-07-03 | 2019-01-03 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10207220B2 (en) | 2017-03-15 | 2019-02-19 | Jiangnan Environmental Protection Group Inc. | Method and apparatus for removing sulfur oxides from gas |
| US10953365B2 (en) | 2018-07-20 | 2021-03-23 | Jiangnan Environmental Protection Group Inc. | Acid gas treatment |
| US11027234B2 (en) | 2018-04-13 | 2021-06-08 | Jiangnan Environmental Protection Group Inc. | Oxidization of ammonia desulfurization solution |
| US11224838B2 (en) | 2019-12-26 | 2022-01-18 | Jiangnan Environmental Protection Group Inc. | Controlling aerosol production during absorption in ammonia-based desulfurization |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102371108A (en) * | 2010-08-20 | 2012-03-14 | 中国石油化工集团公司 | Method for producing sulfuric acid by oxygen-enriched air incineration of acid gas containing hydrogen sulfide |
| CN101979130B (en) * | 2010-10-25 | 2013-03-20 | 四川大学 | Method for removing hydrogen sulfide from industrial gas in recycling way |
| CN102502526A (en) * | 2011-10-10 | 2012-06-20 | 瓮福（集团）有限责任公司 | Method for treating hydrogen sulfide-containing tail gas from large-scale coal chemical plant |
| CN105080309B (en) * | 2014-05-23 | 2018-01-05 | 国网山西省电力公司电力科学研究院 | A kind of purifying treatment method and device for sulfur hexafluoride detection tail gas |
| CN107469588A (en) * | 2016-06-07 | 2017-12-15 | 上海宝钢化工有限公司 | SO in industrial tail gas can be reduced2The device and its exhaust gas treating method of concentration |
| CN109369465A (en) * | 2018-12-10 | 2019-02-22 | 黔西县黔希煤化工投资有限责任公司 | Use H2The method of S gas deep processing production antineoplastic fluorouracil medicine intermediate |
-
2002
- 2002-06-25 CN CN 02137839 patent/CN1251965C/en not_active Expired - Fee Related
Cited By (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102743956A (en) * | 2012-07-25 | 2012-10-24 | 南京博图硫酸技术设计中心 | Process for preparing sulfuric acid by using regenerative gas obtained from active coke desulphurization |
| US9370745B2 (en) | 2013-04-24 | 2016-06-21 | Jiangsu New Century Jiangnan Environmental Protection Co., Ltd | Flue gas-treating method and apparatus for treating acidic tail gas by using ammonia process |
| US10207220B2 (en) | 2017-03-15 | 2019-02-19 | Jiangnan Environmental Protection Group Inc. | Method and apparatus for removing sulfur oxides from gas |
| US10675584B2 (en) | 2017-03-15 | 2020-06-09 | Jiangnan Environmental Protection Group Inc. | Method and apparatus for removing sulfur oxides from gas |
| US10413864B2 (en) | 2017-03-15 | 2019-09-17 | Jiangnan Environmental Protection Group Inc. | Method and apparatus for removing sulfur oxides from gas |
| US10406477B2 (en) | 2017-03-15 | 2019-09-10 | Jiangnan Environmental Protection Group Inc. | Method and apparatus for removing sulfur oxides from gas |
| US10413865B2 (en) | 2017-05-25 | 2019-09-17 | Jiangnan Enviromental Protection Group Inc. | Ammonia-based desulfurization process and apparatus |
| US10092877B1 (en) | 2017-05-25 | 2018-10-09 | Jiangnan Environmental Protection Group Inc. | Dust removal and desulfurization of FCC exhaust gas |
| US10213739B2 (en) | 2017-05-25 | 2019-02-26 | Jiangnan Environmental Protection Group Inc. | Dust removal and desulfurization of FCC exhaust gas |
| US10343110B2 (en) | 2017-05-25 | 2019-07-09 | Jiangnan Environmental Protection Group Inc. | Dust removal and desulfurization of FCC exhaust gas |
| US10016721B1 (en) | 2017-05-25 | 2018-07-10 | Jiangnan Environmental Protection Group Inc. | Ammonia-based desufurization process and apparatus |
| US10561982B2 (en) | 2017-05-25 | 2020-02-18 | Jiangnan Environmental Protection Group Inc. | Ammonia-based desulfurization process and apparatus |
| US10399033B2 (en) | 2017-05-25 | 2019-09-03 | Jiangnan Environmental Protection Group Inc. | Ammonia-based desulfurization process and apparatus |
| US10471383B2 (en) | 2017-05-25 | 2019-11-12 | Jiangnan Environmental Protection Group Inc. | Dust removal and desulfurization of FCC exhaust gas |
| US10406478B2 (en) | 2017-05-25 | 2019-09-10 | Jiangnan Environmental Protection Group Inc. | Ammonia-based desulfurization process and apparatus |
| US10589212B2 (en) | 2017-06-14 | 2020-03-17 | Jiangnan Environmental Protection Group Inc. | Ammonia-adding system for ammonia-based desulfurization device |
| US10583386B2 (en) | 2017-06-14 | 2020-03-10 | Jiangnan Environmental Protection Group Inc. | Ammonia-adding system for ammonia-based desulfurization device |
| US10159929B1 (en) | 2017-06-14 | 2018-12-25 | Jiangnan Environmental Protection Group Inc. | Ammonia-adding system for ammonia-based desulfurization device |
| US10427097B2 (en) | 2017-07-03 | 2019-10-01 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10618001B2 (en) | 2017-07-03 | 2020-04-14 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10421040B2 (en) | 2017-07-03 | 2019-09-24 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10556205B2 (en) | 2017-07-03 | 2020-02-11 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US20190001267A1 (en) | 2017-07-03 | 2019-01-03 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10561984B2 (en) | 2017-07-03 | 2020-02-18 | Jiangnan Environmental Protection Group Inc. | Desulfurization absorption tower |
| US10112145B1 (en) | 2017-09-07 | 2018-10-30 | Jiangnan Environmental Protection Group Inc. | Method for controlling aerosol production during absorption in ammonia desulfurization |
| US10369517B2 (en) | 2017-09-07 | 2019-08-06 | Jiangnan Environmental Protection Group Inc. | Method for controlling aerosol production during absorption in ammonia desulfurization |
| US10449488B2 (en) | 2017-09-07 | 2019-10-22 | Jiangnan Environmental Protection Group Inc. | Method for controlling aerosol production during absorption in ammonia desulfurization |
| US10357741B2 (en) | 2017-09-07 | 2019-07-23 | Jiangnan Environmental Protection Group Inc. | Method for controlling aerosol production during absorption in ammonia desulfurization |
| US11027234B2 (en) | 2018-04-13 | 2021-06-08 | Jiangnan Environmental Protection Group Inc. | Oxidization of ammonia desulfurization solution |
| US10953365B2 (en) | 2018-07-20 | 2021-03-23 | Jiangnan Environmental Protection Group Inc. | Acid gas treatment |
| US11529584B2 (en) | 2018-07-20 | 2022-12-20 | Jiangnan Environmental Protection Group Inc. | Acid gas treatment |
| US11224838B2 (en) | 2019-12-26 | 2022-01-18 | Jiangnan Environmental Protection Group Inc. | Controlling aerosol production during absorption in ammonia-based desulfurization |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1385364A (en) | 2002-12-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1251965C (en) | Preparation of high-concntration surlfuric acid using hydrogen sulfide contained acidic gas | |
| WO2020135135A1 (en) | Process and device for processing low-purity sulfur and auxiliary salt waste liquid produced by desulfurization of coke oven gas | |
| CN1164480C (en) | Combined production of high concentration sulphuric acid by using acid gas containing hydrogen sulfide and sulphur | |
| CN101054165A (en) | Device and method of reclaim and processing tail gas of sulfur | |
| CN109052335A (en) | A kind of method of sulfur gas reduction Waste Sulfuric Acid sulfur dioxide liquid and sulfuric acid | |
| CN103303877A (en) | Comprehensive multi-gas source low-concentration SO2 fume recycling acid-making technological process | |
| CN103552992A (en) | System and method for preparing acid by using sulfur-containing wastewater through dry method | |
| CN1939840A (en) | Tail gas treatment and reutilization for calcium carbide stove | |
| CN110894064A (en) | Device and method for preparing sulfuric acid by cracking and regenerating waste sulfuric acid and/or sulfur-containing waste liquid | |
| CN106379868A (en) | Method for preparing sulfuric acid by burning sulfur-containing waste liquid | |
| CN107673314B (en) | Low-concentration SO2Method for preparing sulfuric acid through one-to-two conversion of flue gas | |
| CN102050430B (en) | Method for preparing high concentration sulfuric acid by cracking low concentration sulfuric acid | |
| CN102614775A (en) | Method for removing and recovering low concentration sulfur dioxide in industrial exhaust gas | |
| CN204563939U (en) | Coke oven flue gas denitration desulfurization and UTILIZATION OF VESIDUAL HEAT IN integration system | |
| CN209161488U (en) | A kind of system of sulfur gas reduction Waste Sulfuric Acid sulfur dioxide liquid and sulfuric acid | |
| CN111071996A (en) | Method for preparing sulfuric acid | |
| CN111689477A (en) | Wet process and apparatus for preparing sulfuric acid from high-hydrocarbon-content acidic gas | |
| CN209507588U (en) | Processing coke oven gas desulfurization produces the device of low bright sulfur sulphur and secondary salt waste liquid | |
| CN114738769A (en) | Acid making process and system for reducing emission of sulfuric acid tail gas | |
| JPS61168506A (en) | Production of sulfuric trioxide from fuming sulfuric acid | |
| CN213623283U (en) | Device for preparing acid from acid gas containing hydrogen sulfide | |
| CN211770310U (en) | Device for preparing sulfuric acid by cracking and regenerating waste sulfuric acid and/or sulfur-containing waste liquid | |
| CN212127523U (en) | Combined treatment system for waste sulfuric acid and acid gas | |
| CN218033168U (en) | Acid making system capable of reducing discharge amount of sulfuric acid tail gas | |
| CN107469588A (en) | SO in industrial tail gas can be reduced2The device and its exhaust gas treating method of concentration |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060419 Termination date: 20120625 |