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Application of surface-modified MH material for H 2 separation using temperature/pressure swing absorption–desorption was studied. The substrate alloy had the following composition LaNi 3.55 Co 0.75 Al 0.4 Mn 0.3 , and the surface modification was carried out through fluorination followed by aminosilane functionalization and electroless deposition of Pd. The material was found to have good poisoning tolerance towards surface adsorbates, even for the large (∼1.5 kg) batches. Feasibility of its application for H 2 separation from gas mixtures (up to 30% CO 2 and 100 ppm CO) was demonstrated by testing of a prototype H 2 separation system (∼280 g of MH in two reactors), and H 2 separation reactor (0.75 kg of MH). The H 2 separation was characterized by stable performances in the duration of 250 absorption/desorption cycles. However, the total process productivity was found to be limited by the sluggish H 2 absorption (partial H 2 pressure ⩽2.5 bar, temperature below 100 °C). In the presence of CO 2 and CO, additional deceleration of H 2 absorption was observed at space velocities of the feed gas below 5000 h −1 .

A promising method of hydrogen compression driven by low-grade heat and not requiring the usage of moving parts, is the application of metal hydrides (MH). However, being upscaled to higher productivities necessary for industrial processes (≥1 m 3 H 2 /h STP), the method will inevitably meet a number of problems related to complication of system layout, high costs and significant labour resources for the manufacturing, and low thermal efficiency.This work presents a development of a prototype MH compressor operating in a temperature range 20 to 150°C and providing compression of hydrogen from 10 to 200 bar with average productivity up to 1 m 3 /h. The compressorrealises two stage layout where the first stage uses AB 5 -and the second AB 2 -type hydride-forming intermetallic alloys. A special engineering solution allows for the usage of quite big MH containers (up to 15 kg of the MH material, or ∼2 m 3 STP H 2 capacity), so that the required productivity is provided by just four containers assembled in two compression elements each of which comprises one first- and one second-stage MH containers. The compressor's layout also provides heat regeneration thus reducing the consumption of hot and cold heat transfer fluids and increasing the overall efficiency.

In this paper the theory of hydrogen vibrational excited molecule emission stimulated by plasma ion bombardment of metal hydride cathode surface in condition of gas discharge is discussed. The conception of direct momentum transfer due to collisions of both high-energy plasma ions and atoms with hydrogen atoms, dissolved in metal matrix, is assumed the theory as a basis. It is shown, that the efficiency of this process can be enough high to provide the hydrogen vibrational excited molecule emission out of metal hydride. It is shown, that the intensity of desorbed hydrogen flow linearly depends on flux of bombarding particles. The calculations, based on this mechanism, qualitatively agree with experimental data.