Sulfur–Iodine plant for large scale hydrogen production by nuclear power

The Sulfur–Iodine (S_I) cycle, driven by nuclear power, seems to be one of the main candidates to produce hydrogen on a large scale. A new S_I process flowsheet is proposed, set up at CEA and simulated by ProSim code and, based on that, data and results on the coupling of the thermochemical plant with a Very High Temperature Nuclear Reactor (VHTR) are presented. The scale up to industrial level, the conceptual design and cost estimation of the plant are then presented and discussed. In order to support a high temperature aggressive environment, well established chemical engineering methods as well as non traditional materials, devices and technologies have been selected. The influence of the adopted technology on the H2 cost has also been investigated and is widely discussed, comparing two different cases. An economic sensitivity analysis carried out by varying the hydrogen production level is presented, showing that an optimum H2 production exists and, due to relevant heat recovery processes, the minimum cost is not achieved for the maximum allowable H2 production rate. Finally an optimized layout for the minimum cost plant, set up adopting the pinch technique, is presented leading to a further reduction of H2 production costs.