焦炉多余热回收系统的分析及优化

doi:10.16085/j.issn.1000-6613.2019-1089

摘要/Abstract

摘要：

为了研究焦炉多余热回收系统中能量的利用情况，依据分析理论，通过对某焦化厂实际案例的计算，对现有的余热回收方案进行分析，指出3个子系统运行过程中的能量回收的薄弱环节。结果表明：干熄焦、荒煤气、烟气余热回收系统的效率分别为55.16%、17.18%、51.75%，干熄焦系统的损主要为换热过程中产生的不可逆换热损失，荒煤气系统的损主要为出口损以及不可逆换热损失，烟道系统的损主要为烟气出口损。在此基础上依据各等级能量匹配利用的原则对原方案进行优化，并使用分析理论对其计算并分析。结果表明：优化过后的余热回收系统的总效率为58.72%，相比优化之前提高了11.07%，系统总不可逆换热损降低了155.49MJ/t干煤。

关键词: 焦炉, 余热回收, 分析, 优化

Abstract:

In order to study energy utilization efficiency in the process of coke oven multi-heat recovery, three subsystems of waste heat recovery in coke plant were analyzed based on the analysis theory, and the weak links of energy utilization in the process of waste heat recovery were pointed out. The results showed that the exergy efficiency of the three studied systems as coke dry quenching, raw coke oven gas and flue gas were 55.16%, 17.18% and 51.75%, respectively. The main exergy loss of coke dry quenching system is irreversible heat transfer loss in the process of heat transfer. Exergy loss of raw coke oven gas system is mainly outlet exergy loss and irreversible heat transfer loss and the main exergy loss of flue gas system is outlet exergy loss. On this basis, the original plan was optimized according to the principle of energy matching and utilization of different grades, and exergy analysis theory was used to calculate and analyze it. The results showed that the total exergy efficiency of the waste heat recovery system after optimization was 58.72%, which was 11.07% higher than that before optimization, while overall irreversible replacement loss of exergy of the system decreased by 155.49MJ/t dry coal.

Key words: coke oven, waste heat recovery, exergy analysis, optimization

中图分类号:

TQ52

尹珩宇,樊俊杰,邓加晓,杜梅芳,陈时选. 焦炉多余热回收系统的分析及优化[J]. 化工进展, 2020, 39(3): 1181-1186.

Hengyu YIN,Junjie FAN,Jiaxiao DENG,Meifang DU,Shixuan CHEN. Analysis and optimization of waste heat recovery system in coke oven[J]. Chemical Industry and Engineering Progress, 2020, 39(3): 1181-1186.

图/表 8

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名称	设计工况
排焦量/t·h^-1	140
红焦温度/℃	1050
排焦温度/℃	200
循环气体流量/m3·h^-1	199000
干熄炉进口气体温度/℃	130
干熄炉出口气体温度/℃	—
余热锅炉进口气体温度/℃	970
余热锅炉出口气体温度/℃	170
荒煤气总流量/m3·h^-1	58800
进口荒煤气温度/℃	680
出口荒煤气温度/℃	500
烟气流量/m3·h^-1	266000
进口烟气温度/℃	265
出口烟气温度/℃	160
干熄焦系统蒸汽压力/MPa	5.8
荒煤气系统蒸汽压力/MPa	1.7
烟道废气系统蒸汽压力/MPa	0.85

名称	设计工况
排焦量/t·h^-1	140
红焦温度/℃	1050
排焦温度/℃	200
循环气体流量/m3·h^-1	199000
干熄炉进口气体温度/℃	130
干熄炉出口气体温度/℃	—
余热锅炉进口气体温度/℃	970
余热锅炉出口气体温度/℃	170
荒煤气总流量/m3·h^-1	58800
进口荒煤气温度/℃	680
出口荒煤气温度/℃	500
烟气流量/m3·h^-1	266000
进口烟气温度/℃	265
出口烟气温度/℃	160
干熄焦系统蒸汽压力/MPa	5.8
荒煤气系统蒸汽压力/MPa	1.7
烟道废气系统蒸汽压力/MPa	0.85

收入			输出
合计	1004.53	100.00	合计	1004.53	100.00
项目	数量/MJ·t^-1	比例/%	项目	数量/MJ·t^-1	比例/%
焦炭带入	655.28	65.23	中压蒸汽	554.07	55.16
焦炭烧损	326.94	32.54	焦炭出口	50.58	5.04
给水带入	22.37	2.23	散热	40.46	4.03
			气体散失	1.93	0.19
			排污损	2.92	0.29
			不可逆换热损	354.57	35.30

收入			输出
合计	1004.53	100.00	合计	1004.53	100.00
项目	数量/MJ·t^-1	比例/%	项目	数量/MJ·t^-1	比例/%
焦炭带入	655.28	65.23	中压蒸汽	554.07	55.16
焦炭烧损	326.94	32.54	焦炭出口	50.58	5.04
给水带入	22.37	2.23	散热	40.46	4.03
			气体散失	1.93	0.19
			排污损	2.92	0.29
			不可逆换热损	354.57	35.30

收入			输出
合计	275.11	100.00	合计	275.11	100.00
项目	数量/MJ·t^-1	比例/%	项目	数量/MJ·t^-1	比例/%
荒煤气带入	266.03	96.70	中压蒸汽	48.91	17.78
红焦辐射带入	9.07	3.30	荒煤气出口	181.46	65.96
给水带入	1.25	0.45	散热	10.12	3.68
			排污损	1.20	0.44
			不可逆换热	33.42	12.15