论文总字数：22729字

摘 要

生物质能是唯一能替代化石资源转化为燃料和基础化工原料，实现CO₂ 零排放的可再生资源，因此研究生物质能利用成为各国热点。生物质气化过程伴随焦油产生，焦油成分复杂，液态焦油粘稠，对燃气下游设备产生危害。

课题组开发了自冷却焦油深度多级脱除工艺，利用冷却与吸收两过程进行焦油脱除，并设置解吸过程实现循环使用。前期实验以正十二烷、环己烷为焦油模拟物，在一定条件下可实现98%的综合脱除率；后期使用ASPEN PLUS进行冷却与吸收解吸两部分的模拟，以苯酚与萘作为模拟物，达到了63%脱除率，脱除结果并不理想。课题前期阶段本文也进行工艺全流程模拟探索，结果与实际相差较大。因此，本文选择深入探讨以激冷单元焦油脱除机理，分析操作参数对焦油脱除的影响。主要研究内容和结果如下：

1. 建立了激冷单元模型，设置选定模型参数，分别选用RadFrac单元操作模型和PENG-ROB物性方法，进行模拟成功得到净化过程的基本参数。分析了气液进口温度、流量等工艺参数对脱除过程的影响，结果表明试剂种类与流量的影响最大，调整试验参数得到，流量为2000 Nm³/h的燃气，焦油模拟物苯含量15 g/m³，试剂进口温度20℃，正十二烷最佳流量为4500 kg/h，塔板数15时，可达到99%的脱除效果；四乙二醇最佳流量为3500 kg/h，塔板数10时，脱除率可达97%；甲苯最佳流量2000 kg/h，塔板数为10，可达97%苯脱除率。
2. 与苯结构性质相似体系如甲苯在小流量下，吸收作用下实现97%苯脱除率，但存在大于100g/m³的试剂剩余量；与苯结构非相似的体系如正十二烷与四乙二醇需要在大流量下，冷却作用下实现显著的脱除效果，同时可以实现近乎于零的试剂剩余量，对比不同性质试剂存在不同的脱除机理。

关键词: 焦油模拟物；激冷单元；ASPEN PLUS；苯

ABSTRACT

Biomass is the only replaceable renewable resources from fossil resources into fuel and basic chemical raw materials, which may achieve CO₂ zero emissions. Therefor it has received wide attention all over the world. Biomass high temperature gasification process with the production of tar inevitably, tar composition is complex, and liquid tar is viscosity, the gas downstream equipment may harm.

A novel biomass tar removal method named as Self-cooling Coupled with Absorption Technology(SCCAT),is proposed in which the heavy tar is removed by the chilling process and the light tar by absorption process. In previous experiments, n-dodecane and cyclohexane were used as the tar simulants, under certain conditions could achieve 98% removal rate. A process simulation software named ASPEN PLUS were used to simulate the tar removal process, phenol and naphthalene were used as the tar simulants to achieve 63% removal rate , the simulation results were not ideal. In the early stage of the project, the whole process simulation was also carried out, and the result had big difference comparing with the actual process In this paper, the effects of the operation parameters on tar removal are discussed in depth in order to study the mechanism of tar removal. The main research contents and results are as follows:

(1)The model of chilling unit and process parameters were selected, RadFrac was used to establish absorption tower model and PENG-ROB physical property was used to calculate the simulation model. Through the simulation analysis, the basic parameters of the purification process were obtained. Benzene was used as the tar simulants, using N₂ to simulate the mixed gas, N₂was 2000 Nm³/h, the flow rate of benzene was15 g/m³, the inlet absorbent’s temperature was 20℃,the optimal flow rate of n-dodecane was 4500kg/h, the tray number was15, the removal rate of benzene reached to 99%. The optimal flow rate of tetraethylene glycol was 3500 kg/h, the tray number was 10, the removal rate of benzene reached to 97%. The optimal flow rate of toluene was 2000 kg/h, the tray nuber was 10,the removal rate of benzene reached to 97%.

(2)The reagent which has similar structure with benzene such as toluene could reach to high removal under the low flow rate with the effect of the absorbtion. The residual of toluene was over 100g/m³. The reagent which has non similar structure with benzene needs high flow rate to reach high benzene removal rate, and the residual of reagent close to 0g/m³. As seen above, there are different mechanisms for the different properties of reagent.

Keywords: tar simulation; cooling unit; ASPEN PLUS; benzene

目录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1 背景与意义 1

1.2 生物质气化瓶颈 1

1.3 ASPEN PLUS软件介绍 3

1.4 ASPEN PLUS激冷应用简述 4

1.5 本文研究目的与内容 5

第二章 焦油模拟物激冷脱除模型建立 7

2.1 ASPEN模拟流程步骤 7

2.2 ASPEN 关键参数 7

2.2.1 物性方法 8

2.2.2 数值计算 9

2.3 激冷单元模拟 9

2.3.1 模拟组分的选择 9

2.3.2 模型建立 10

2.3.3 冷却剂的确定 10

2.4 小结 12

第三章 结果与讨论 14

3.1 冷却剂种类对净化性能的影响 14

3.1.1正十二烷 14

3.1.2甲苯 14

3.1.3四乙二醇 15

3.2 温度参数对净化性能的影响 15

3.2.1 气体进口温度 15

3.2.2 冷却剂进口温度 19

3.3 塔参数对净化性能的影响 23

3.4 冷却剂量对净化性能的影响 26

3.5 小结 30

第四章 结论 32

参考文献 33

致谢 34

第一章 绪论

1.1 背景与意义

化石能源消耗随经济发展日益增大，而余量减少；同时二氧化碳的排放引起全球环境污染也在日益严重。为了解决这样的问题，寻找开放新能源迫在眉捷^[1]。生物质能是唯一能替代化石资源转化为燃料和基础化工原料，实现CO₂ 零排放的可再生资源，因此研究生物质能利用成为各国热点^[2]。同时我国生物质能资源丰富，开发生物质应用技术，符合我国三农国情，促进新农村建设^[3]。

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