纯氧克劳斯工艺的模拟与优化

高德志; 喻昕蕾; 陶迅; 丁路; 代正华; 王辅臣

doi:10.14135/j.cnki.1006-3080.20201204003

纯氧克劳斯工艺的模拟与优化

doi: 10.14135/j.cnki.1006-3080.20201204003

华东理工大学上海市煤气化工程技术研究中心，上海 200237

基金项目: 国家自然科学基金(21978092)

详细信息

作者简介:
高德志(1996—)，男，福建泉州人，硕士生，研究方向为克劳斯工艺流程模拟与优化。E-mail：623686540@qq.com

通讯作者:
王辅臣，E-mail：wfch@ecust.eud.cn

中图分类号: TQ125.11
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出版历程
- 收稿日期: 2020-12-04
- 网络出版日期: 2021-01-25

Simulation and Optimization of Pure Oxygen Claus Process

Shanghai Engineering Research Center of Coal Gasification, East China University of Science and Technology, Shanghai 200237, China

摘要

摘要: 克劳斯工艺是高效处理H₂S等酸性气体并回收硫磺的技术之一。工业过程处理低浓度酸性气体时，需要加入助燃气体以保证火焰稳定，但会导致多环芳烃、有机硫等有害物质增加。采用纯氧燃烧，则可在无需引入助燃气体的情况下提高炉膛温度、增加烃类杂质的去除率。基于Aspen plus软件建立克劳斯工艺全流程模型，使用某工厂数据进行验证，探究了进口酸气组成、氧气浓度及进气流量、氧气预热温度、炉膛压力及第二催化段反应器温度等工艺参数对克劳斯工艺的影响，并以硫收率为目标函数利用Aspen plus优化工具计算了最佳操作参数。优化结果表明：硫收率从优化前的98.31%提高到优化后的99.08%，尾气中主要污染物SO₂的排放量由优化前的0.350 kmol/h减少至优化后的0.278 kmol/h，降低了20.6%，并节约了酸性气体和空气预热所需的热量9133.38 kJ/kmol。
- 克劳斯工艺 /
- 低浓度酸性气体 /
- 纯氧 /
- 流程模拟 /
- 优化
Abstract: The Claus process is one of the technologies for efficient acid gas processing and sulfur recovering. In industry, it is necessary to add combustion-supporting gas for combustion to ensure flame stability when processing low concentration acid gas, which leads to problems such as increased production of harmful substances like polycyclic aromatic hydrocarbons and organic sulfur. The use of pure oxygen for combustion can not only increase the temperature of the furnace and the removal rate of hydrocarbon impurities, but also avoid the problems caused by the addition of combustion-supporting gas. In this paper, a full Claus process model was built in the Aspen Plus and was validated by industrial data. The influence of the inlet acid gas composition, oxygen concentration, oxygen preheating temperature, furnace pressure, oxygen gas intake and the temperature of the second catalytic stage reactor on the Clause process were studied. The optimization tool in Aspen Plus was used to calculate the best operating parameters. The optimized results showed that the sulfur recovery efficiency increased from 98.31% — 99.08% and the emission of SO₂, the main pollutant in the tail gas, reduced from 0.350 kmol/h to 0.278 kmol/h, reduction rate at 20.6%. Moreover, it saved 9133.38 kJ/kmol(acid gas) heat required for the preheating of the acid gas and air.
- Claus process /
- low concentration acid gas /
- pure oxygen /
- process simulation /
- optimization

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图 1 Aspen plus克劳斯硫回收工艺流程图

Figure 1. A schematic diagram of the Claus process using Aspen plus

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图 2 氧气摩尔分数对克劳斯硫回收过程的影响

Figure 2. Effect of oxygen molar fraction on the performance of the Claus process

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图 3 氧气摩尔分数对n(H₂S)/n(SO₂)的影响

Figure 3. Effect of oxygen molar fraction on the n(H₂S)/n(SO₂)

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图 4 α对克劳斯硫回收过程的影响

Figure 4. Effect of α on the performance of the Claus process

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图 5 α对总硫收率和第一催化段出口处n(H₂S)/n(SO₂)的影响

Figure 5. Effect of α on the performance of the total sulfur recovery efficiency and n(H₂S)/n(SO₂) of the first catalysis stage outlet

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图 6 氧气预热温度对克劳斯硫回收过程的影响

Figure 6. Effect of oxygen preheating temperature on the performance of the Claus process

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图 7 炉膛压力对克劳斯硫回收过程总硫收率的影响

Figure 7. Effect of furnace pressure on the sulfur recovery efficiency of the Claus process

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图 8 第二催化段反应器温度对克劳斯硫回收过程的影响

Figure 8. Effect of the temperature of the second catalysis stage reactor on the performance of the Claus process

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表 1 进料气组分摩尔分数

Table 1. Gas molar composition of the inlet

	Molar fraction/%
	H₂	Ar	N₂	CO	CO₂	H₂S	H₂O	NH₃	O₂	CH₃OH
AG1	0	0	29.00	0	20.00	50.00	0	0	0	1.00
AG2	0.50	0	20.00	0.50	67.00	2.00	0	0	0	10.00
AG3	12.40	0.20	0.20	8.00	75.00	1.00	3.00	0.20	0	0
AIR1	0	0.93	78.09	0	0.03	0	0	0	20.95	0

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表 2 RF1内考虑的反应

Table 2. Considered reactions in RF1

No.	Reaction
1	$ {\rm{N}}{{\rm{H}}}_{3} \to {\rm{0.5N}}_{{2}}{+1.5}{{\rm{H}}}_{{2}} $
2	$ {{\rm{H}}_2}{\rm{S + 1}}{\rm{.5}}{{\rm{O}}_2} \to {{\rm{H}}_2}{\rm{O + S}}{{\rm{O}}_2}$

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表 3 RF2内考虑的反应及其动力学参数

Table 3. Considered reactions and kinetic parameters in RF2

No.	Reaction	Reaction rate expressions	Reference
3	${{\rm{H}}_{\rm{2}}}{{\rm{S}}} \leftrightarrow {{\rm{H}}_{\rm{2}}}{\rm{ + 0}}{\rm{.5}}{{\rm{S}}_{\rm{2}}}$	$-{r_{ {\rm{ {H} }_2S} } }=1.63\times{10^{-1} }{ {\rm{e} }^{{\frac{ {45.1} }{ {RT} } } } }{p_{\rm{ { {H} }_2}S} }p_{\rm{S_2} }^{0.5}-1.36\times{10^{-6} }{ {\rm{e} }^{{\frac{ {23.4} }{ {RT} } } }}{p_{\rm{H_2} } }{p_{\rm{S_2} } }$	[19]
4	${\rm{CO} } + 0.5{{\rm{S}}_2} \leftrightarrow {\rm{COS}}$	$- {r_{ {\rm{CO} } } } = 3.18\times {10^5}{ {\rm{e} }^{{\frac{ {15.3} }{ {RT } } } }}\left( { {c_{\rm{CO} } }{c_{ { {\rm{S} }_2} } } - \dfrac{1}{ { {k_{\rm{eq2} } } } }{c_{\rm{COS} } }c_{ { {\rm{S} }_2} }^{0.5} } \right)$	[20]
5	$ {\rm{C}}{{\rm{O}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}} \leftrightarrow {\rm{CO + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}$	$-{r_{\rm{C{O_2} } } }=8.59\times{10^{10} }{ {\rm{e} }^{{\frac{ {64.7} }{ {RT} } } } }\left( { {c_{\rm{C{O_2} } } }c_{ {\rm{ {H} }_2} }^{0.5}-\dfrac{1}{ {{k_{eq3} } } }\dfrac{ { {c_{\rm{CO} } }{c_{ {\rm{ {H} }_2O} } } } }{ {c_{ {\rm{ {H} }_2} }^{0.5} } } } \right)$	[21]
6	$ {\rm{CO + }}{{\rm{H}}_{\rm{2}}}{\rm{S}} \leftrightarrow {\rm{COS + }}{{\rm{H}}_{\rm{2}}} $	$-r{\rm{_{CO} } }=1.59\times{10^5}{ {\rm{e} }^{{\frac{ {26.5} }{ {RT} } } } }\left({ {c_{\rm{CO} } }c_{ {\rm{ {H} }_2S} }^{0.5}-\dfrac{1}{ {{k_{eq4} } } }\dfrac{ { {c_{\rm{COS} } }{c_{ {\rm{ {H} }_2} } } } }{ {c_{ {\rm{ {H} }_2S} }^{0.5} } } }\right)$	[22]
7	$ {{\rm{H}}_{\rm{2}}}{\rm{S + 0}}{\rm{.5S}}{{\rm{O}}_{\rm{2}}} \leftrightarrow {\rm{0}}{\rm{.75}}{{\rm{S}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}$	$-{r_{ {\rm{ {H} }_2S} } } =3.18\times{10^3}{ {\rm{e} }^{{\frac{ {14.3} }{ {RT} } } } }{c_{ {\rm{ {H} }_2S} } }c_{\rm{S{O_2} } }^{0.5}-3.11\times{10^1}{ {\rm{e} }^{{\frac{ {8.5} }{ { {RT} } } }} }{c_{\rm{ { { {H} }_2}O} } }c_{ {\rm{S_2} } }^{0.75}$	[23]

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表 4 炉膛出口气模拟结果与工厂工况比较结果

Table 4. Simulated results versus plant data for composition of gas from furnace

Gas	q/(kmol·h⁻¹)
Gas	Plant date	Simulated results	Absolute error/%
H₂	1.636	1.698	3.81
Ar	0.600	0.600	0.01
N₂	63.453	63.448	0.01
CO	1.038	1.233	18.77
CO₂	27.079	26.868	0.78
H₂S	9.155	9.175	0.22
COS	0.119	0.133	12.13
SO₂	4.637	4.789	3.27
H₂O	17.930	17.836	0.53
S₂	5.458	5.387	1.31

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表 5 优化结果与运行工况重要参数比较

Table 5. Important parameters contrast of the optimization results with operating parametrs

Important parameters	x(O₂)/%	Split ratio	Air molar flow/(kmol·h⁻¹)	T₀/℃	T_a/℃	T_s/℃	T_f/℃	Y_S/%	n(H₂S)/n(SO₂) of the 1^st catalysis stage	Outlet SO₂ mole flow of off-gas/(kmol·h⁻¹)
Operating parameters	20.95	0.80	60.90	80.00	240.00	218.00	1019.39	98.31	1.99	0.350
Optimization results	99.60	1.00	14.09	25.00	25.00	180.00	1314.11	99.08	2.00	0.278

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