热电冷却微反应器
天然气水合物，特别是甲烷水合物，是一种极具潜力的能源资源。然而，其开采与利用过程中涉及复杂的物理化学过程，如热电冷却微反应堆和压强控制等。热电冷却微反应堆技术的引入，有助于实现对天然气水合物开采过程的精确温度控制，提高其开采效率。同时，压强控制则是确保三相（水、天然气、固态水合物）共存状态稳定的关键。通过精细调控压强，可以维持天然气水合物的稳定状态，避免其分解或转化，从而确保开采过程的顺利进行。这些技术的综合应用，将为天然气水合物的开采与利用开辟新的途径。
图1（a）微型反应器的二维设计 （b） 热电冷却系统组件。
Fig. 1 (a) Two-dimensional design of the microreactor. (b) Thermoelectric cooling system assembly.
热电冷却微型反应堆的设计
用AutoCAD设计二维微反应器，然后用传统微电子加工技术在硅上蚀刻出微通道(横截面为200 μm × 200 μm)。将1毫米厚的耐热玻璃粘合到基板上来创建三维微结构。
如图1(a)所示，图中包括混合区(4.5 μL)和结晶区(27.7 μL)，这两个区域由隔热透蚀区分开。操作流量范围为2至80 μL min−1，停留时间为0.4 min至16.1 min。
装置可实现程序升温和控温，其中包含不锈钢压缩夹具（图1b），能够将流体输送到设备和从设备输送流体。还使用了30 A热电模块（最大65 W），可以用导热胶将微反应器的背面连接到换热器的冷却侧（见图1b），以最大化1.05 K s−1的冷却速率。
通过使用热敏电阻监测设备温度，并通过控制器控制设备温度。干燥的室内空气被连续输送到散热箱，以最大限度地提高热传递的驱动力，从而最大限度地降低冷却速度。通过红外热像仪进一步表征了微反应器的温度分布。
Design of a thermoelectrically-cooled microreactor.
Design 2D microreactors using AutoCAD and then etch microchannels on silicon using traditional microelectronic processing techniques(Cross section is 200 μ M × two hundred μ M).Glue 1mm thick heat-resistant glass onto the substrate to create a three-dimensional microstructure.
As shown in Figure 1 (a), the figure includes mixing(4.5 μ L) and crystallization zone (27.7 μ L)， which were separated by a thermal insulation through-etch. Operation at flowrates in the range of 2 to 80 μL min−1 enabled residence times from 0.4 min to 16.1 min.
The design of the device also achieves gradual temperature changes and isothermal operation.The device includes a stainless steel compression chuck (Figure 1b), which can transport fluid to and from the equipment.A 30 A thermoelectric module (maximum 65 W) was also used, and the back of the microreactor can be connected to the cooling side of the heat exchanger using thermal adhesive (see Figure 1b) to maximize a cooling rate of 1.05 K s−1
By using thermistors to monitor device temperature and controlling device temperature through a controller.Dry indoor air is continuously transported to the heat dissipation box to maximize the driving force of heat transfer, thereby minimizing the cooling rate.
The temperature distribution of the microreactor was further characterized using an infrared thermal imager.
图2 甲烷(sI)水合物结晶研究实验装置工艺流程图
Fig. 2 Process flow diagram of the experimental apparatus for the study of methane (sI) hydrate crystallizations.
实验仪器：
如图2所示，甲烷和去离子水通过两台高压注射泵输送到微反应操作系统。一个背压调节器(最大压力为200 bar)连接下游以保持恒定压力。两个压力传感器(最大压力为207 bar，精度±0.5%)分别安装在微系统的上游和下游，以监测进、出口压力。微反应器的压降计算为传感器之间的差值。
Experimental apparatus:
As shown in Figure 2, methane and deionized water are transported to the micro reaction operating system through two high-pressure injection pumps.A backpressure regulator (max pressure 200 bar) is connected downstream to maintain a constant pressure.Two pressure sensors ( max pressure 207 bar , accuracy of ± 0.5%) are installed upstream and downstream of the microsystem to monitor the inlet and outlet pressures, respectively.The pressure drop of the microreactor is calculated as the difference between sensors.
图3 甲烷水合物形成过程
Fig 3 Formation process of methane hydrate
把压强逐步控制在60bar，冰和甲烷就能结晶成甲烷水合物。
图3(a)为 水合物数据库中的甲烷水合物相图。
图3(b)为微反应器温度阶跃变化。
图3(c)是在不同温度条件下拍摄的微通道示例视频帧(流动方向为从右向左)。
第一步:结冰;第二步:冰转化为甲烷水合物;
第三步:甲烷水合物解离生成甲烷气体和液态水;第四步:甲烷水合物的形成。
Gradually controlling the pressure at 60 bar, ice and methane can crystallize into methane hydrates.
Figure 3 (a) shows the phase diagram of methane hydrates in the hydrate database.
Figure 3 (b) shows the temperature step change of the microreactor.
Figure 3 (c) shows an example video frame of microchannels captured under different temperature conditions
Step 1: Ice formation; Step 2: Ice is converted into methane hydrate;
Step 3: Methane hydrate dissociates to generate methane gas and liquid water; Step 4: Formation of methane hydrates.
图4 甲烷水合物在微通道中传播
Figure 4 Methane hydrate propagation in microchannels
图4显示了在60bar和3.0 K过冷温度下的甲烷水合物沿微通道传播的快照，并进行传播速率测量。用虚线标出水合物膜的相界。可以看到，逐帧分析的显微照片提供轴向传播精度为15 fps。
图中甲烷的流速为2.5 mg min - 1，扩散方向和甲烷流动方向用箭头表示。图4（b）为（a）中红框放大图，此时微通道内三相共存(无甲烷气体、液态水和固体水合物)。
Figure 4 shows a snapshot of methane hydrate propagation along microchannels at a pressure of 60.8 bar and a subcooling temperature of 3.0 K.
The flow rate of methane in the figure is 2.5 mg min-1, and the diffusion direction and methane flow direction are indicated by arrows.Figure 4 (b) shows the enlarged red box in (a), where three phases coexist in the microchannel (without methane gas, liquid water, and solid hydrates).
图5 微型化工反应器
Fig 5 Micro chemical reactor
微化工反应器
航烨借助于精密扩散结合技术，以固体基质制造含有较小通道尺寸和结构的可用于化学反应的三维结构元件——微化工反应器图（5）反应介质在反应层通道中流动并在通道中完成所要求的反应，换热介质分布在反应层的两侧提供反应所需温度。
Micro chemical reactor
Hangye utilizes precision diffusion bonding technology to manufacture three-dimensional structural components with small channel sizes and structures that can be used for chemical reactions using a solid substrate - Microreactor Diagram (5). The reaction medium flows in the reaction layer channel and completes the required reaction in the channel, while the heat exchange medium is distributed on both sides of the reaction layer to provide the required temperature for the reaction.
