CN101837235B - 一种低耗高效的锅炉烟气脱硫工艺 - Google Patents

一种低耗高效的锅炉烟气脱硫工艺 Download PDF

Info

Publication number
CN101837235B
CN101837235B CN200910119053A CN200910119053A CN101837235B CN 101837235 B CN101837235 B CN 101837235B CN 200910119053 A CN200910119053 A CN 200910119053A CN 200910119053 A CN200910119053 A CN 200910119053A CN 101837235 B CN101837235 B CN 101837235B
Authority
CN
China
Prior art keywords
tower
ammonium
ammonium sulfate
flue gas
concentration
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
Application number
CN200910119053A
Other languages
English (en)
Other versions
CN101837235A (zh
Inventor
高翥
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nine Technologies Ltd
Original Assignee
BEIJING JIUZHOUMEIDIAN ENVIRONMENTAL PROTECTION ENGINEERING Co Ltd
BEIJING JIUZHOU MEIDIAN TECHNOLOGY Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by BEIJING JIUZHOUMEIDIAN ENVIRONMENTAL PROTECTION ENGINEERING Co Ltd, BEIJING JIUZHOU MEIDIAN TECHNOLOGY Co Ltd filed Critical BEIJING JIUZHOUMEIDIAN ENVIRONMENTAL PROTECTION ENGINEERING Co Ltd
Priority to CN200910119053A priority Critical patent/CN101837235B/zh
Publication of CN101837235A publication Critical patent/CN101837235A/zh
Application granted granted Critical
Publication of CN101837235B publication Critical patent/CN101837235B/zh
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

本发明公开了一种脱除锅炉烟气中二氧化硫副产硫铵化肥的工艺技术,高温烟气经浓缩塔降温进入脱硫塔脱硫后排空。亚硫铵吸收液在塔内循环脱硫后送入氧化塔,将亚硫铵充分氧化为硫铵,后进入浓缩塔与高温烟气逆流换热。硫铵溶液浓度由约30%提高到45%达到过饱和,即有硫铵晶体析出。含有硫铵晶体的悬浊液经过旋流、过滤、干燥为成品。本发明由于高温烟气先进入浓缩塔,使烟气温度降低的同时,对硫铵溶液进行了提浓,省去硫铵蒸发系统,简化了工艺;采用脱硫塔外氧化,使氧化更加充分,提高了产品硫铵化肥的品质,同时由于在脱硫塔内不生成硫酸铵,大大增加了溶液的吸收催动力,从而提高了吸收率,可降低液气比,装置更加节能。

Description

一种低耗高效的锅炉烟气脱硫工艺
技术领域:
本发明涉及环境保护领域大气污染治理脱硫脱氮技术,尤其涉及一种低耗高效的锅炉烟气脱硫工艺。
背景技术:
现有同类技术及存在的不足如下:
目前的湿式氨法脱硫技术主要有氨-肥法、氨-酸法、氨-亚硫酸铵法。
1、氨-肥法脱硫技术
采用氨水作为脱硫剂,在脱硫塔内大循环量使硫酸铵与亚硫酸铵溶液与烟气中的SO2反应脱除SO2,生成副产物硫酸铵与亚硫酸铵,在脱硫塔底部利用空气曝气的方法将亚酸铵氧化成硫酸铵,硫酸铵溶液排出后经过滤、蒸发、离心、干燥后生产出硫酸铵晶体包装入库,完成脱硫及硫铵产品的回收过程。
该方法存在以下缺陷:
1)脱硫塔内循环液中由于含有大量的硫酸铵,硫酸铵对SO2没有吸收作用,因此造成塔内汽液比增大,不但造成了动力消耗大,而且使烟气温度损失严重(排烟温度<50℃)含水饱和的低温烟气对设备腐蚀严重,还需对出口烟气再加温,使运行成本加大。
2)塔内曝气氧化的方式亚硫酸铵的氧化率只能达到40-50%,因此造成硫铵产品中含有大量的亚硫酸铵成分,亚硫酸铵没有任何肥效,而且很不稳定,用在农田里很容易烧苗,因此该工艺生产的硫酸铵产品品质很低。
3)该技术方法的硫铵分离是采用蒸发的方式来脱除水分,需要消耗大量的蒸汽,因此硫铵副产品回收的运行成本很高。
2、氨-酸法脱硫技术
氨酸法与氨-肥法工艺类似,只是用硫酸、磷酸、硝酸等酸将脱硫产物亚硫铵酸解,生成相应的铵盐和气体二氧化硫,铵盐送制肥装置制成成品氮肥或复合肥;气体二氧化硫既可制造液体二氧化硫又可送硫酸制酸装置生产硫酸。该方法主要用于冶金行业。
3、氨-亚硫铵法
该方法采用氨水作脱硫剂,稀释到所需浓度后喷入脱硫塔与SO2反应生成亚硫酸铵溶液,部分溶液循环使用,未循环的亚硫酸铵溶液由于浓度较低(远低于饱和状态)作为副产物溶液外排,从而完成脱硫过程。
该方法存在以下缺陷:
1)副产物不能循环利用,造成成本浪费和二次污染,若采用蒸发的方式回收,运行成本又太高。
2)部分气态氨极易随烟气逃逸,造成二次污染。
发明内容:
针对现有技术中存在的问题,本发明提出了一种低耗高效的锅炉烟气脱硫工艺,以解决现有技术能耗高、副产品品质低以及对环境的二次污染问题,本工艺流程设计合理,脱硫率高,回收的硫铵产品品质纯净,且没有三废排放。
本发明采用如下的技术方案来实现:
一种低耗高效的锅炉烟气脱硫工艺,其中包括下列步骤:
1)氨水制备
2)脱硫反应
3)亚硫酸铵氧化
4)硫酸铵溶液浓缩
5)硫酸铵溶液分离、提纯、回收
在上述技术方案中氨水要在氨水配置罐中配置,氨水的浓度为8~20%,配置好的氨水通过泵送入脱硫塔底部。
高温烟气(130-140℃)经过电除尘后进入硫铵浓缩塔,与来自硫铵缓冲罐的硫铵溶液逆流接触换热,使烟气温度降低后到50℃-70℃后进入脱硫塔,与塔底循环泵来的亚硫酸铵发生反应,反应过程如下:
2NH3+H2O+SO2=(NH4)2SO3                    (1)
(NH4)2SO3+SO2+H2O=2NH4HSO3                (2)
2NH4HSO3+2NH3=2(NH4)2SO3                  (3)
正常吸收工艺控制是按(2)、(3)反应循环进行,脱硫塔设计三层喷淋,塔顶有两层除雾器,防止液滴腐蚀烟道。
塔底的亚硫酸铵溶液通过吸收塔排出泵送到氧化塔,与鼓风机来的空气进行反应,氧化塔内的主要反应为:
(NH4)2SO3+1/2 O2=(NH4)2SO4
NH4HSO3+1/2 O2=NH4HSO4
NH4HSO4+(NH4)2SO3=(NH4)2SO4+NH4HSO3
自吸收塔来的亚硫酸铵从氧化塔底部进入氧化塔,亚硫酸铵溶液从塔的底部自下而上流动,氧化空气与亚硫酸铵液并流流动,亚硫酸铵与空气中的氧接触,被氧化成硫酸铵。塔内设有四块筛板,用以将空气气泡破碎,增加气液接触面积。溶液到达氧化塔顶部后经下液管送到浓缩塔循环液槽。氧化塔内硫酸铵的浓度控制在30-35%,氧化率在95%以上。
浓缩塔循环液槽内的硫酸铵溶液经浓缩塔给料泵送至浓缩塔顶部喷嘴,硫酸铵溶液和自塔底来的烟气逆流接触,将溶液浓缩,液体浓度达到45%以上,并有硫酸铵晶体析出。因此,在浓缩塔底部设有液体扰动器,以防止在塔底部产生结晶。浓缩后的硫酸铵溶由硫酸铵浆液排出泵送往硫铵制备工段的悬液分离器进行固液分离,分离出的晶体硫酸铵经下部的离心机脱水,使含水率<5%,然后送入干燥器干燥,使含水率<1%。液相全部返回浓缩塔循环液槽。含水率<1%的硫铵包装后作为成品出售。
本发明将起到以下积极效果:
1、本技术脱硫率高,脱硫率>96%,同时有脱氮的效果,脱氮率可达35%以上。
2、本技术运行成本低,蒸汽消耗是氨-肥法工艺的20%,电耗是氨-肥法工艺的40%,硫铵回收产生可观的“正效益”,符合国家倡导的循环经济和可持续发展。
3、副产品为高纯度的硫铵晶体(满足硫酸铵GB535-1995),不含亚硫酸铵成分。
4、本工艺氨的逃逸率低,无三废排放,不对环境造成二次污染。
附图说明:
图1所示为本发明一种低耗高效的锅炉烟气脱硫工艺流程图。
具体实施方式:
本技术采用氨水作为吸收剂,将液氨转化成8~20%的氨水。
锅炉来的热烟气经电或布袋除尘后进入硫铵浓缩塔,在脱硫装置的进口和出口各设一个双挡板隔离门,在旁路烟道上设一个可调节旁路挡板门,用于事故状态或检修时用。硫酸铵溶液由缓冲罐底部的氧化液排出泵经高位缓冲槽喷入硫酸铵浓缩塔,与热烟气逆流接触,烟气被降温至50-70℃后进入脱硫塔,硫酸铵溶液中的水分被高温烟气蒸发浓缩至饱和状态后在浓缩塔底部集中,待溶液浓度达到45%以上时,由硫铵浆液排出泵送入旋分器进行固液分离。
启动脱硫循环泵将塔底的混合液通过喷淋层喷淋,与来自硫铵浓缩塔的烟气逆流接触,控制塔内的液汽比为8~9,使SO2与硫酸铵反应,脱硫后的烟气经过塔顶两级除雾器后进入烟囱排放,塔顶除雾器要定期用工艺水清洗,以减小系统阻力,塔底液由吸收塔排出泵送到氧化塔。
在氧化塔内来自氧化风机的空气与吸收塔排出泵送来的亚硫酸铵溶液反应,为了保证氧化率,氧化空气的量要高于理论值的数倍,塔底设置循环泵,当氧化塔内液位达到40~50%时,打开汽液联通管上的阀门,使硫铵溶液进入硫铵循环液槽。
经过烟气浓缩后的硫酸铵溶液由硫铵浆液排出泵送到旋分器进行固液分离,分离出的晶体硫酸铵通过下部的离心机脱水,含水率小于5%的晶体送到干燥器,进一步脱水至水含量小于1%,经过螺旋给料机送到包装机包装成袋入库,完成整个过程。

Claims (4)

1.一种低耗高效的锅炉烟气脱硫工艺,其特征在于使用亚硫酸铵作为脱硫剂,高温烟气经硫铵浓缩塔降温后进入脱硫塔,烟气温度由130~140℃降低到50~70℃,从而有效地利用了烟气的低位热能;脱硫塔内的氨水要过量,使塔内的亚硫酸氢氨全部转化为亚硫酸铵,脱硫塔循环液汽比控制在8~9,塔内的pH值控制在5.8-6.2之间;亚硫铵在塔内循环与烟气中的二氧化硫进行脱硫反应完成脱硫过程,将脱硫后的塔底亚硫铵溶液送入氧化塔内,使亚硫铵充分转化为硫酸铵溶液,而后进入浓缩塔与烟气逆流换热,使硫铵溶液中的水分被蒸发,溶液硫铵浓度由30~35%,提高到45%,达到过饱和,过饱和后即有硫铵晶体析出,含有硫铵晶体的悬浊液经过旋流、过滤,固体经干燥成为成品,液体再返回浓缩塔。
2.根据权利要求1所述的锅炉烟气脱硫工艺,其特征在于从脱硫塔出来的亚硫酸铵溶液与鼓风机鼓入的空气顺流接触进行氧化,塔内并设有四块筛板,从而使溶液与空气接触充分,避免了气体在塔内的偏流现象,提高了氧化率,使亚硫酸铵充分氧化为硫酸铵,氧化塔内硫酸铵的浓度控制在30~35%。
3.根据权利要求1所述的锅炉烟气脱硫工艺,其特征在于从硫酸铵浓缩塔出来的硫酸铵溶液经旋分器进入过滤器、离心机脱水后再送入螺旋给料机、干燥器进行干燥、包装即为硫铵化肥产品。
4.根据权利要求3所述的锅炉烟气脱硫工艺,其特征在于从离心机脱出的溶液中含有45%的硫酸铵,该溶液经泵送回到浓缩塔循环液槽中,再经浓缩,使溶液达到过饱和。
CN200910119053A 2009-03-19 2009-03-19 一种低耗高效的锅炉烟气脱硫工艺 Expired - Fee Related CN101837235B (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN200910119053A CN101837235B (zh) 2009-03-19 2009-03-19 一种低耗高效的锅炉烟气脱硫工艺

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN200910119053A CN101837235B (zh) 2009-03-19 2009-03-19 一种低耗高效的锅炉烟气脱硫工艺

Publications (2)

Publication Number Publication Date
CN101837235A CN101837235A (zh) 2010-09-22
CN101837235B true CN101837235B (zh) 2012-08-29

Family

ID=42741055

Family Applications (1)

Application Number Title Priority Date Filing Date
CN200910119053A Expired - Fee Related CN101837235B (zh) 2009-03-19 2009-03-19 一种低耗高效的锅炉烟气脱硫工艺

Country Status (1)

Country Link
CN (1) CN101837235B (zh)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105080307A (zh) * 2014-05-12 2015-11-25 陈汇宏 一种尾气的脱硫脱硝方法、所用设备及其产品的应用
CN105833678A (zh) * 2016-04-26 2016-08-10 安阳化学工业集团有限责任公司 一种利用解吸废液辅助进行燃煤锅炉烟气脱硫的方法
CN109621653A (zh) * 2018-12-29 2019-04-16 中冶南方都市环保工程技术股份有限公司 一种可资源化回收的焦炉烟气氨法脱硫系统及方法
CN113663499A (zh) * 2021-09-07 2021-11-19 安阳盈德气体有限公司 一种焚烧炉尾气高效氨法脱硫工艺

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101053760A (zh) * 2007-02-13 2007-10-17 武汉都市环保工程技术股份有限公司 烧结烟气氨法脱硫系统
CN200998639Y (zh) * 2007-02-09 2008-01-02 李培生 浓缩结晶和吸收氧化组合式氨法脱硫塔
CN101143291A (zh) * 2006-09-13 2008-03-19 史选增 一种低能耗高品质硫酸铵化肥回收的湿式氨法脱硫工艺

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101143291A (zh) * 2006-09-13 2008-03-19 史选增 一种低能耗高品质硫酸铵化肥回收的湿式氨法脱硫工艺
CN200998639Y (zh) * 2007-02-09 2008-01-02 李培生 浓缩结晶和吸收氧化组合式氨法脱硫塔
CN101053760A (zh) * 2007-02-13 2007-10-17 武汉都市环保工程技术股份有限公司 烧结烟气氨法脱硫系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
黄诗坚.氨法洗涤脱硫的经济性分析.《电力环境保护》.1999,第15卷(第3期), *

Also Published As

Publication number Publication date
CN101837235A (zh) 2010-09-22

Similar Documents

Publication Publication Date Title
AU2018328418B2 (en) Method for controlling aerosol production during absorption in ammonia desulfurization
CN101579602B (zh) 一种节能高品质硫酸铵回收的氨法脱硫工艺
US11224838B2 (en) Controlling aerosol production during absorption in ammonia-based desulfurization
CN200998639Y (zh) 浓缩结晶和吸收氧化组合式氨法脱硫塔
CN100518889C (zh) 一种低能耗高品质硫酸铵化肥回收的湿式氨法脱硫工艺
CN103252158B (zh) 脱硫系统及其脱硫工艺
CN102228777B (zh) 双氧化氨法脱硫工艺及装置
CN2799059Y (zh) 塔内结晶氨法脱硫塔
CN101433798B (zh) 塔外氧化提浓的高效湿式氨回收法脱硫方法及其装置
CN102078752A (zh) 多级氧化吸收氮氧化物废气制备亚硝酸钠的方法
CN102755829B (zh) 一种脱硫剂及其应用
CN101844030A (zh) 一种提高脱硫副产品硫铵品质的方法及系统
CN105233647B (zh) 一种硫化铵溶液脱硫脱硝的方法
CN101757844B (zh) 一种氨法烟气脱硫方法及其设备
CN101862582A (zh) 分塔式锅炉烟气脱硫工艺
CN100506351C (zh) 一种回收烟气中二氧化硫生产硫铵的方法和装置
CN100534583C (zh) 以氨为原料回收烟气中so2的方法和装置
CN103058435A (zh) 一种循环处理锅炉热烟气和脱硫废水的方法
CN101862583A (zh) 一种适合钢厂烧结机烟气脱硫的工艺
CN101422688B (zh) 氨-硫铵湿法烟气脱硫并诱导结晶回收硫酸铵的工艺
CN102745726A (zh) 利用脱硫废液生产七水硫酸镁的方法
CN101837235B (zh) 一种低耗高效的锅炉烟气脱硫工艺
CN102205204B (zh) 冷热态出料的湿式氨法脱硫浓缩工艺
CN103657367A (zh) 一种单塔式钙法脱硫转双塔式氨法脱硫的装置与工艺
CN102976359B (zh) 一种氨法脱硫生产硫酸铵的方法

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
ASS Succession or assignment of patent right

Owner name: BEIJING JIUZHOU MEIDIAN ENVIRONMENTAL PROTECTION E

Free format text: FORMER OWNER: GAO ZHU

Effective date: 20120111

C41 Transfer of patent application or patent right or utility model
TA01 Transfer of patent application right

Effective date of registration: 20120111

Address after: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Applicant after: Beijing Jiuzhou Meidian Technology Co., Ltd.

Co-applicant after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Address before: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Applicant before: Beijing Jiuzhou Meidian Technology Co., Ltd.

Co-applicant before: Gao Zhu

Effective date of registration: 20120111

Address after: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Applicant after: Beijing Jiuzhou Meidian Technology Co., Ltd.

Co-applicant after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Address before: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Applicant before: Beijing Jiuzhou Meidian Technology Co., Ltd.

Co-applicant before: Gao Zhu

C14 Grant of patent or utility model
GR01 Patent grant
C56 Change in the name or address of the patentee
CP02 Change in the address of a patent holder

Address after: 100191 peony building, room 2, Huayuan Road 407, Haidian District, Beijing

Patentee after: Beijing Jiuzhou Meidian Technology Co., Ltd.

Patentee after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Address before: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Patentee before: Beijing Jiuzhou Meidian Technology Co., Ltd.

Patentee before: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Address after: 100191 peony building, room 2, Huayuan Road 407, Haidian District, Beijing

Patentee after: Beijing Jiuzhou Meidian Technology Co., Ltd.

Patentee after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Address before: 100107, Beijing, Chaoyang District Beiyuan Road, proud City, Fu Fu Center, Tianlong Park, block B, room 1203

Patentee before: Beijing Jiuzhou Meidian Technology Co., Ltd.

Patentee before: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Pay the Fees

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Pay the Fees

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification of Termination of Patent Right

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification of Termination of Patent Right

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Go Through Formalities Rectification of Restoration of Right

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Go Through Formalities Rectification of Restoration of Right

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification of Decision on Request for Restoration of Right

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification of Decision on Request for Restoration of Right

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Pay the Fees

Addressee: Beijing Jiuzhou Meidian Technology Co., Ltd.

Document name: Notification to Pay the Fees

DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Document name: Notification of Termination of Patent Right

Addressee: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Document name: Notification of Termination of Patent Right

DD01 Delivery of document by public notice
CP01 Change in the name or title of a patent holder

Address after: 100191 room 407, Mudan venture building, 2 Huayuan Road, Haidian District, Beijing

Co-patentee after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Patentee after: Nine Technologies Ltd

Address before: 100191 room 407, Mudan venture building, 2 Huayuan Road, Haidian District, Beijing

Co-patentee before: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Patentee before: Beijing Jiuzhou Meidian Technology Co., Ltd.

Address after: 100191 room 407, Mudan venture building, 2 Huayuan Road, Haidian District, Beijing

Co-patentee after: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Patentee after: Nine Technologies Ltd

Address before: 100191 room 407, Mudan venture building, 2 Huayuan Road, Haidian District, Beijing

Co-patentee before: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Patentee before: Beijing Jiuzhou Meidian Technology Co., Ltd.

CP01 Change in the name or title of a patent holder
DD01 Delivery of document by public notice

Addressee: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Document name: Notification of Termination of Patent Right

Addressee: Beijing Jiuzhoumeidian Environmental Protection Engineering Co., Ltd.

Document name: Notification of Termination of Patent Right

DD01 Delivery of document by public notice
CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20120829

Termination date: 20190319