6.1.3德士古气化炉的提温操作_金刚

德士古气化炉的提温操作金　刚　张　涛(山东省兖矿鲁南化肥厂　滕州　277527)摘要　通过更换煤种使生产消耗得到了大幅度降低,生产能力得到了较大的提高,但渣中可燃物较设计指标提高了2～3倍。

为此进行了提高炉温的试验,考察渣中可燃物随炉温的变化关系,同时考核不同渣中可燃物含量下的氧耗和煤耗。

关键词　德士古气化炉　灰渣可燃物　操作温度 兖矿鲁南化肥厂的德士古气化装置自1993年4月试车以来进行了较多的技术改造,生产能力由年产8万t合成氨提高到年产10.7t,生产用煤由原来的单一“七五”煤发展成多矿点混煤。

随着生产产量的提高、使用煤种的增多,灰渣中可燃物含量也有所升高(表1)。

分析其原因,认为操作炉温过低是主要因素,因此在2000年4月进行了提高炉温的试验工作。

表1　不同煤种灰渣可燃物含量项目1993年1994年1995年1996年1998年煤种七五七五+北宿七五+北宿北宿+杨村+落陵北宿+井亭+级索+落陵灰渣可燃物(%)10～1515～2015～202530～45操作温度(℃)145014001400135013501　试验方案的制定本次系统运行从2000年3月11日开始,试验时系统运行稳定,各项指标已得到优化,试验结果应是具有代表性的。

德士古气化炉高温热电偶的使用寿命一般不超过1周。

本次试验选在非初始开车阶段,热电偶已不能指示,只能以气体成份为参考来标定炉温。

尽管甲烷含量能较快地反映炉温,但变化较快,受系统其它因素影响较大。

C O+H2的百分含量随炉温的升高而降低,虽变化慢一些,但受其它因素干扰小,炉温与CO+H2含量的对应关系较为确定,再现性较好,所以选定以CO+H2的含量标定炉温。

1.1　试验目的本次试验的主要目的是考察渣中可燃物随炉温的变化关系,同时考核不同渣中可燃物含量下的氧耗、煤耗。

1.2　试验原则及注意事项(1)本次试验氧气流量不变、压力保持稳定在(3.8±0.05)MPa,氧气纯度在99.6%以上,通过逐渐降低煤浆泵转速以提高O/C值,最终达到提温之目的。

(2)以合成气中CO+H2的百分含量每降低1%为一个阶段,每个阶段稳定运行24h,每个阶段从8∶00开始,气体分析又增加了9∶00和11∶00 2次(原是每个双点分析1次)。

(3)炉温提升应缓慢,煤浆泵转速应缓慢降低。

(4)试验时应严格监视合成气温度(≤218℃)、合成气成份、支撑板温度(≤25℃)、炉壁温度(≤260℃)、甲烷含量、排渣情况等,在上述参数不出现异常时才能进行下一步的试验,否则试验终止。

(5)仪表车间应保持在线甲烷表的准确性,并每天校验1次。

(6)试验期间灰渣取样每班2次(原每班1次),分别在接班后的第三、第六小时取样;煤质分析室分白班、中班随时分析,分析结果及时上报至相关部门。

(7)试验期间操作人员应真实地记录工艺参数,认真巡回检查,气化炉壁温每2小时用红外测温仪实测1次。

1.3　试验步骤(1)从目前运行状况开始(C O+H2=83.85%),逐步降低煤浆泵转速,提高O/C值,使合成气中C O48+H 2的含量为82%～83%。

(2)第二阶段再降低煤浆泵的转速,使合成气中C O +H 2的含量为81%～82%。

(3)第三阶段再降低煤浆泵的转速,使合成气中C O +H 2的含量为80%～81%。

(4)第四阶段再降低煤浆泵的转速,使合成气中C O +H 2的含量为79%～80%。

表2　试验前后数据对比项目①试验前平均值②第一阶段③第二阶段＊同比增加②-①同比增加③-①CO +H 2(%)83.8582.7081.84-1.15-2.01CO 2(%)15.9416.9517.74+1.01+1.80CH 4(×10-6)627259NH 3产量(t /d )328.25328.18329.62-0.07+1.37煤气产量(km 3/d )873.35882.70887.40+9.35+14.05CO +H 2产量(km 3/d )732.3730.0726.3-2.3-6.0总耗氧量(km 3/d ,标态)263.9264.8267.2+0.9+3.3总投煤浆量(m 3/d )520.2506.7494.5-13.5-25.7比氧耗[m 3/1000m 3(CO +H 2),标态]360.4362.7367.9+2.3+7.5比煤耗[kg /1000m 3(CO +H 2)]565.3554.0541.0-11.3-24.3产气率(m 3煤气/m 3煤浆)1679.01742.01794.5+63+115.5平均煤浆浓度(%)66.3266.5166.21+0.19-0.11灰渣可燃物(%)43.9636.4731.83-7.49-12.13　＊　折算成24h (5)分析渣中可燃物,如果含量降至20%,试验结束并恢复原工况。

2　试验情况介绍2.1　试验过程(1)第一阶段4月5日8∶00开始提炉温至10∶00基本调整完毕,目标值是C O +H 2的含量为82%～83%并维持2h 稳定运行。

(2)第二阶段4月6日8∶00开始提炉温至10∶00调整完毕,目标值CO +H 2含量为81%～82%,但因6日15∶00跳车而停止试验。

2.2　数据对比试验前后数据对比见表2。

3　试验结果(1)操作炉温的确定依据是煤的灰熔点,一般在煤的灰熔点FT 以上50℃左右。

由于所使用的煤的灰熔点较低,所以炉温也较低,试验过程中高出正常炉温约100℃,具有较大的风险性。

(2)本次试验虽然只进行了2个阶段即被终止,但从数据上看已显示出趋向性。

(3)从表2可以看出,在其它条件不变的情况下(氧气流量、煤浆浓度、产氨量),提高炉温,比氧耗增加,比煤耗降低,灰渣可燃物降低。

1000m 3(CO +H 2)多耗氧分别为2.3m 3(标态)和7.5m 3(标态),1000m 3(C O +H 2)少耗煤分别为11.3kg 和24.3kg 。

由此可见,提高炉温能提高煤的利用率,降低生产成本,但还要综合考虑比氧耗的增加和耐火砖的寿命等一系列因素。

(收稿日期　2001-10-08)新型低温甲醇催化剂一种操作温度较传统工业催化剂低100℃的甲醇合成催化剂目前正由美国Apyron 工艺技术公司开发。

传统的甲醇催化剂一般利用水溶性金属盐,通过共沉淀作用,由铜、锌或铝的氧化物制备。

新型催化剂的化学组成与之相同,但制造方法不同。

在新的合成工艺中,金属氧化物与无机粘合剂(如胶质硅)混合,形成基质,活性金属组份分散于其间。

混合时,用无机酸喷淋基质,以加快交联速度,生成较传统催化剂活性表面积更大、热稳定性更高的凝结物。

凝结物成型后,在300～1000℃下煅烧即得到成品。

据称,这种方法的生产成本低于共沉淀法。

此外,由于催化剂具有较好的热稳定性,可降低甲醇生产的能耗和成本。

目前该方法已用于生产氮氧化物的分解催化剂,在1000℃下使用53h 而无任何活性损失。

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