As organic porous soil, peat is prone to self-heating ignition, a type of spontaneous initiation of fire that can take place at ambient temperatures without an external source. Despite the urgency to tackle peat fires, the understanding of the self-heating ignition of peat is insufficient. In this study, a computational model that integrates the mechanisms of heat transfer, mass transfer and chemistry is incorporated with a three-step reaction scheme that includes drying, biological reaction and oxidative oxidation to simulate the self-heating ignition of smouldering peat. The model is first validated against 13 laboratory-scale experiments from literature. For critical ignition temperature (T_ig), the model gives accurate predictions for all experiments with a maximum error of 5°C. The validated model is then upscaled to predict T_ig for field-size peat soil layers and compared with the predictions using a one-step scheme. The three-step scheme is shown to give more reliable predictions of T_ig than the one-step scheme. According to the simulation results, for a 1.5-m-deep peat layer, self-heating ignition can occur at an average ambient temperature above 40°C. This is the first time that a multi-step scheme is used to simulate the self-heating ignition of peat, aiming to help in the prevention and mitigation of these wildfires.

泥炭作为有机多孔土壤，容易自燃，这是一种自发起火，可在环境温度下发生而无需外部来源。尽管迫切需要解决泥炭火灾，但对泥炭自热点火的理解仍然不够。在这项研究中，结合了传热，传质和化学机理的计算模型与三步反应方案结合在一起，该方案包括干燥，生物反应和氧化氧化，以模拟闷烧泥炭的自热点火。该模型首先根据文献中的13个实验室规模的实验进行了验证。临界点火温度（T _ig），该模型可为所有实验提供准确的预测，最大误差为5°C。然后将经过验证的模型进行放大，以预测田间大小的泥炭土层的T _ig，并使用一步计划将其与预测值进行比较。示出了三步方案比单步方案给出了更可靠的T _ig预测。根据模拟结果，对于1.5米深的泥炭层，在高于40°C的平均环境温度下会发生自热点火。这是首次采用多步骤方案来模拟泥炭的自热点火，旨在帮助预防和缓解这些野火。