粉煤热解干法熄焦余热回收工艺流程分析及模试

doi:10.16085/j.issn.1000-6613.2021-0328

摘要/Abstract

摘要：

针对现有粉煤热解生产过程中水资源消耗大、半焦水分含量高、环境污染严重等问题，本文提出利用惰性气体作为熄焦介质实现干法熄焦以及余热回收干燥煤粉的新工艺。通过系统模拟研究不同循环介质（氮气、二氧化碳、烟气及煤气等）的初始温度、水汽含量、流量等操作条件对热解半焦熄焦冷却后温度和煤干燥预热后温度的影响规律，分析该工艺节水、节能效果，开展了万吨级粉煤热解模试验证。结果表明，采用干法熄焦处理热解半焦并回收余热的工艺技术可行，熄焦后半焦温度和煤干燥预热出口温度与干燥介质种类无显著关系，与气体比热容密切相关；与湿法熄焦相比，干法熄焦工艺具有显著节能效果且耗水为零，在满足工艺要求的同时可以回用半焦显热的65%~75%。理论分析和试验均证实了干法熄焦余热回收具有良好的应用前景。

关键词: 热解, 模拟, 焦化, 系统工程, 热传导

Abstract:

Aiming at the problems of the large consumption of water resources, high moisture content of semi-coke, and severe environmental pollution in the production process of pulverized coal pyrolysis, the process flow of semi-coke dry quenching and waste heat recovery for drying pulverized coal by using inert gas as the cooling medium was proposed. The influence of initial temperature, water content, flow rate of different circulation media (nitrogen, carbon dioxide, flue gas, and coal gas) on the temperature of quenching semi-coke and preheated coal was studied by system simulation. The effect of water-saving and energy-saving was analyzed, and the model test based on 10000-ton pulverized coal pyrolysis was carried out. The results showed that the technology of waste heat recovery from dry quenching of semi-coke was feasible. The temperature of semi-coke after coke quenching and the outlet temperature of preheating coal have no significant relationship with the type of cooling medium but were closely related to the cooling medium's specific heat. Compared with the wet quenching, the dry process had a significant energy-saving effect and zero water consumption, which could reuse 65%—75% of the sensible heat of semi-coke while meeting the process requirements. Theoretical analysis and experimental results showed that dry quenching waste heat recovery had a good application prospect.

Key words: pyrolysis, simulation, coking, system engineering, heat conduction

中图分类号:

TQ520.6

樊英杰, 党敏辉, 张杰, 吴志强, 杨伯伦. 粉煤热解干法熄焦余热回收工艺流程分析及模试[J]. 化工进展, 2022, 41(1): 182-191.

FAN Yingjie, DANG Minhui, ZHANG Jie, WU Zhiqiang, YANG Bolun. Process analysis and model scale investigation on waste heat recovery from semi-coke dry quenching of pulverized coal pyrolysis[J]. Chemical Industry and Engineering Progress, 2022, 41(1): 182-191.

图/表 19

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工业分析（质量分数，空气干燥基）/%					元素分析（质量分数，空气干燥基）/%
M	A	V	FC		C	H	N	S	O
2.54	8.65	32.20	56.61		74.42	4.3	0.91	0.26	8.92

工业分析（质量分数，空气干燥基）/%					元素分析（质量分数，空气干燥基）/%
M	A	V	FC		C	H	N	S	O
2.54	8.65	32.20	56.61		74.42	4.3	0.91	0.26	8.92

工业分析（质量分数，空气干燥基）/%					元素分析（质量分数，空气干燥基）/%
M	A	V	FC		C	H	N	S	O
0.72	7.96	14.75	76.57		79.68	2.92	1.16	0.19	7.37

工业分析（质量分数，空气干燥基）/%					元素分析（质量分数，空气干燥基）/%
M	A	V	FC		C	H	N	S	O
0.72	7.96	14.75	76.57		79.68	2.92	1.16	0.19	7.37

温度/℃	煤粉比热容/kJ?kg^-1?K^-1	半焦比热容/kJ?kg^-1?K^-1
0	1.329	0.980
50	1.438	1.108
100	1.543	1.230
150	1.644	1.345
200	1.740	1.453
250	1.833	1.555
300	1.921	1.650
350	2.005	1.738
400	2.085	1.820
450	2.161	1.895
500	2.232	1.963
550	2.300	2.024
600	2.363	2.079