Production and recovery chemistry for low-level hydrogen sulfide containing natural gas

含低水平硫化氢天然气的生产与回收化学天然气储量巨大，分布在7个省。已知至少有两个加拿大页岩油是酸性的，可能含有高达500ppm的硫化氢。在运输到市场之前，出于毒性/环境原因，硫化氢必须降至4ppm以下，二氧化碳必须降至2%以下，以保持卡路里含量。硫化氢含量低于2%的生产液不适合传统的硫化氢氧化以回收商业元素硫；因此，加拿大生产商需要替代化学工艺来实现4ppm的目标。整个研究的重点是通过了解这些低水平的硫化氢来源和探索替代的氧化过程来满足这一需求。具体的研究目标是：(I)扩展热页岩储层酸化的动力学模型，(Ii)评估密相CO2中的高压催化作用，以及(Iii)探索联苯和二苯醚的共晶混合物中的工业硫化学。(I)热页岩储层酸化的动力学模拟我们以前已经证明，非微生物储层酸化可以通过压裂液添加剂(如十二烷基硫酸钠)的降解而发生。我们最近的工作集中在自然硫化物(硫化氢或金属硫化物)的快速氧化，以在有限的时间内在水库中产生元素硫。然后，这种元素硫可以氧化其他碳氢化合物或液压油添加剂，从而热生成硫化氢。这方面的研究将继续，重点是凝胶压裂添加剂(与浮水添加剂相比)。这项研究将帮助生产商确定硫化氢何时出现在流体中，以及在一口井的整个生命周期内可以预期产生多少硫化氢。(Ii)密相二氧化碳中的高压催化很难管理低水平硫化氢生产的来源，因为(A)低硫化氢产量不能支持传统克劳斯热反应堆中的火焰，(B)替代低水平选择很少生产商业质量的硫。硫化氢在加压下的催化直接氧化可以在不需要昂贵的纯二氧化碳再压缩的情况下完成，并提供两种增值产品，即二氧化碳和S8。正在应用高压多相催化研究来确定这一过程的操作条件。(Iii)联苯和二苯醚(Dowtherm®A)共熔混合物中的硫化学用于一些硫回收过程，例如聚乙二醇烃类溶剂；然而，由于与元素硫发生反应，不能使用更高的温度。对于替代溶剂，我们正在探索在Dowtherm®A内进行常见的工业硫化学。这三个研究领域的进展有助于新兴低碳能源的安全和可持续发展。

PRODUCTION AND RECOVERY CHEMISTRY FOR LOW-LEVEL H2S CONTAINING NATURAL GASCanada has significant shale gas reserves which span 7 provinces. At least two Canadian shale plays are known to be sour and can contain up to 500 ppm H2S. Before transportation to market the H2S must be reduced to less than 4 ppm for toxicity/environmental reasons and CO2 is reduced to less than 2% to maintain caloric content. Production fluids with less than 2% H2S are not suitable for conventional oxidation of H2S to recover commercial elemental sulfur; therefore, alternative chemical processes are required by Canadian producers to achieve the 4 ppm target. The overall research is focused on addressing this need by understanding these low-level H2S sources and exploring alternative oxidation processes. Specific research goals are aimed at (i) expanding kinetic models for souring of hot shale reservoirs, (ii) evaluating high-pressure catalysis in dense phase CO2, and (iii) exploring industrial sulfur chemistry in a eutectic mixture of biphenyl and diphenyl ether.(i) Kinetic modelling for souring of hot shale reservoirsWe have previously demonstrated that non-microbial reservoir souring can occur through the degradation of fracture fluid additives (e.g., sodium dodecylsulfate). Our more recent work has focused on the rapid oxidation of native sulfides (H2S or metal sulfides) to produce elemental sulfur in the reservoir over a finite time. This elemental sulfur can then oxidize other hydrocarbons or hydraulic fluid additives to thermally generate H2S. Studies will continue in this area by focussing on gel fracture additives (versus slick water additives). This research will help producers identify when H2S will appear in the fluids and how much can be expected over the lifetime of a well.(ii) High-pressure catalysis in dense phase CO2Managing sources of low-level H2S production is difficult, because (a) low H2S production cannot support a flame in the conventional Claus thermal reactor and (b) the alternative low-level options rarely produce commercial quality sulfur. The catalytic direct oxidation of H2S at pressure can be completed without costly recompression of pure CO2 and provide two value-added products; namely CO2 and S8. High-pressure heterogeneous catalysis research is being applied to define the operating conditions for such a process.(iii) Sulfur chemistry in a eutectic mixture of biphenyl and diphenyl ether (Dowtherm® A)Hydrocarbon solvents such as PEG are used in some sulfur recovery processes; however, higher temperatures cannot be used due to reaction with elemental sulfur. For an alternative solvent, we are exploring carrying out common industrial sulfur chemistries within Dowtherm® A. Progress in all three of these research areas help with the safe and sustainable development of emerging low-carbon energy sources.