微波场-水分子协同强化非常规裂解原料裂解的反应机理及调控机制

Traditional steam cracking is not only a high energy consumption process, but also only suitable for light raw materials. And it is difficult to deal with heavy oil, waste polyolefin cracking oil, coal tar and other unconventional cracking resources. The direct heating method, which is represented by the direct heating pyrolysis by superheated steam, is also faced with the difficulties such as too much steam and low cracking efficiency. In order to solve the above problems and realize the effective utilization of unconventional cracking resources. This project puts forward the microwave pyrolysis technology. And a new method based on the interaction between microwave and polar molecules to enhance the heat transfer and reaction is proposed, in order to reduce the energy consumption and improve the yield and selectivity of small molecular olefins. Through the structure design of microwave field, it will form water molecules “volumetric heating” inside the tube and the absorbing layer “surface heating” outside the tube. Then the project will explore the “volumetric heating+surface heating” synergistic effect of heat transfer and microwave characteristics, and achieve heat transfer intensity, uniformity and microwave synergistic effect control. Based on the analysis of the heat transfer design of “volumetric heating + surface heating”, and the analysis of the vaporization process of typical heavy hydrocarbons, the study will reveal the regulation mechanism of the vaporization process of “water molecule heavy hydrocarbon” system. Based on the experimental and simulation analysis of the pyrolysis reaction of typical heavy hydrocarbons, it will reveal the Interaction mechanism between microwave field and the “water molecule -hydrocarbon molecule-free radical” system and the mechanism of microwave effect. The research will provide scientific basis for pyrolysis of heavy oil, waste polyolefin cracking oil and coal tar.

传统蒸汽裂解不仅是高能耗过程，而且只适用于轻质原料，难以处理重质油、废聚烯烃裂解油、煤焦油等非常规裂解资源。以过热蒸汽加热裂解为代表的直接加热法也面临着蒸汽量过多、裂解效率低等难以克服的困难。为解决上述难题，实现非常规裂解资源的有效利用，项目提出微波裂解技术。为降低能耗和提高小分子烯烃的产率和选择性，提出了基于微波与极性分子的相互作用强化传热及反应的思路。通过微波场的结构设计，形成管内水分子“体加热”和管外吸波层“面加热”，探索“体加热+面加热”协同传热和微波作用特性，实现传热强度、均匀性和微波效应协同控制。通过对“面加热+体加热”传热设计和典型重质烃汽化过程分析，揭示“水分子-重质烃”体系汽化过程调控机制。通过对典型重质烃裂解反应的实验和模拟分析，揭示微波场与“水分子-烃分子-自由基”体系反应过程的作用机理和微波效应机制。为重质油、废聚烯烃裂解油、煤焦油的裂解提供科学依据。

传统蒸汽裂解不仅是高能耗过程，而且只适用于轻质原料，难以处理重质油、废聚烯烃裂解油、煤焦油等非常规裂解资源。以过热蒸汽加热裂解为代表的直接加热法也面临着蒸汽量过多、裂解效率低等难以克服的困难。为解决上述难题，实现非常规裂解资源的有效利用，本项目提出微波裂解技术。为降低能耗和提高小分子烯烃的产率和选择性，提出了基于微波与极性分子的相互作用强化传热及反应的思路。通过对典型重质烃裂解反应的实验和模拟分析，揭示微波场与“水分子-烃分子-自由基”体系反应过程的作用机理和微波效应机制。为重质油、废聚烯烃裂解油、煤焦油的裂解提供科学依据。本项目中非常规裂解原料主要来自聚烯烃废塑料热解油。在项目执行期间，全球性新冠肺炎（COVID-19）疫情爆发，大量医疗及民用废弃塑料进入环境，使得白色污染问题异常严重。本项目围绕废塑料微波裂解开展基础研究，重点关注吸波、传热、催化协同强化废塑料微波裂解和调控产物分布，其中吸波材料结构、组成、表面基团和形状是影响反应体系吸波、传热与催化的关键因素。主要裂解原料是聚烯烃废塑料，液体产物是裂解油，该裂解油用于高温裂解生成小分子烯烃，并形成微波裂解两步法。本项目研究内容分为模拟计算和裂解实验两个方面。在计算模拟方面，项目建立了微波加热耦合模型，并进行了典型加热模式和案例的计算，为实验设计和装置选择提供了重要信息。在裂解实验方面，探索了不同实验条件下的原料、微波吸收剂以及产物的相互作用机制。并拓展了裂解原料范围，重点研究废塑料、生物质、煤焦油、废塑料裂解油（蜡）等非常规裂解原料的微波催化裂解。本项目立足现有问题，提出微波裂解技术，将“外加热”改为“内加热”方式。并通过研究吸收剂与原料（产物）在多个尺度的相互作用机制及强化反应机制，提高能源利用效率、实现产物调节。本项目的实验数据和研究成果可以为后续工业化提供有力支撑。