煤炭地下气化注入点可控后退（Controlled Retraction Injection Point，CRIP）工艺能够实现中深层煤炭资源的清洁高效原位开采，将我国富裕的煤炭资源转化为战略或缺的燃气资源。为取代CRIP工艺中氧气和点火液的注入、提高煤层气化反应活性，基于煤炭地下气化生产工艺和微波加热技术特点，创新提出了耦合大功率微波加热的煤炭地下气化CRIP工艺设计，将气化剂和微波发生器产生的微波经由连续油管注入到地下煤层并在目标气化区释放。通过理论分析和实验研究，从微波的产生、传输、释放、与煤层作用、以及产业发展模式等方面分析了该工艺设计在工程实践中面临的难题和解决方案。研究结果表明，耦合大功率微波加热的煤炭地下气化CRIP工艺在技术上是可行的；在煤炭地下气化过程中加热煤层所需的热量较大，大功率磁控管可以满足工业生产规模需求；微波能够通过双层连续油管镀铜的内管外壁和外管内壁间的环形空间远距离传输到地下煤层；微波频率越高，微波功率衰减越快，2 450 MHz和915 MHz频率微波在双层连续油管中传输500 m时，其功率分别衰减至15.6%和32.1%，中深层煤炭地下气化应选用较低频率来远距离、低损耗输送微波；在双层连续油管前端的外管壁面上按一定规则割开缝隙，形成微波释能器，将微波从管线中泄漏出来辐射煤层；原煤在干燥、热解和燃烧阶段都能够较好地吸收微波能而被加热，在有氧条件下煤样温度升高到587 ℃时焦炭被点燃，最高温度可达1 080 ℃；风光电−储能−煤炭地下微波气化融合产业模式能够充分利用绿色能源，实现中深层煤炭清洁高效原位开采。研究能够为微波辅助煤炭地下气化提供理论基础和技术支持。

The Controlled Retraction Injection Point (CRIP) process of underground coal gasification can mine in situ medium-deep coal resources efficiently and transform rich coal resources in China into strategic and scarce gas resources. In order to replace the injections of oxygen and igniting agent and improve the gasification reactivity of coal seam, the CRIP process of underground coal gasification coupled with high-power microwave heating was proposed in this paper based on technical characteristics of underground coal gasification and microwave heating. Gasification agents and microwave generated were injected into the underground coal seam through a continuous oil pipe and released in the target gasification area. Theoretical and experimental research were conducted to grope for solutions to microwave generation, transmission, release, coal seam heating, and industrial development model. The results show that the CRIP process of underground coal gasification coupled with high-power microwave heating is technically feasible. High-power magnetrons can supply a large amount of heat to meet the industrial production scale. Microwave can be transmitted remotely to underground coal seam through the annular space between the inner tube outer wall and the outer tube inner wall coated with copper in the double-layer continuous oil pipe. The higher microwave frequency is, the faster microwave power decays. If 2450 MHz and 915 MHz microwaves are transmitted a distance of 500 m in the double-layer continuous oil pipe, their power decays to 15.6% and 32.1% respectively. Lower frequencies should be selected to transmit microwaves in long distance with low loss in medium-deep underground coal gasification. A microwave energy release device produced by cutting gaps on the outer wall surface at the front end of the double-layer continuous oil pipe according to certain rules can leak out the microwave and radiate the coal seam. Raw coal can absorb microwave energy well and be heated during the drying, pyrolysis, and combustion stages. When the sample temperature rises to 587 ℃, the coke is ignited in the air atmosphere. And a maximum temperature of 1080 ℃ is observed. An integrated industrial model of wind-solar power, energy storage, and underground microwave gasification of coal is able to fully utilize green energies and achieve clean and efficient in-situ mining of medium-deep coal seams. The conclusions in the present study provide the theoretical basis and technical support for microwave assisted underground coal gasification.