A pulse jet system and method is disclosed. In an example, the pulse jet system includes a combustion chamber, intake ports to deliver combustion agents to the combustion chamber, an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber, and an exhaust to exit the cooled gas from the expansion chamber. In another example, the pulse jet system includes a combustion chamber with intake ports to deliver combustion agents to the combustion chamber, wherein the combustion chamber is part of a four cycle engine. The pulse jet system also includes an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber.

A reactor for carrying out an endothermic reaction, in particular a high-temperature reaction, in which a product gas is obtained from a feed gas, wherein: the reactor surrounds a reactor interior; the reactor is configured to provide a reactor bed in a reaction zone of the reactor interior, which reactor bed comprises a large number of solid material particles; the reactor is also configured to guide the feed gas into the reaction zone; in order to heat the feed gas, the reactor is designed to heat the solid material particles in the reaction zone such that, by transferring heat from the solid material particles to the feed gas, the feed gas in the reaction zone can be heated to a reaction temperature in order to participate as a starting product in the endothermic reaction for producing the product gas.

Invention presents a method of increasing the CO to H.sub.2 ratio of syngas. The method comprises passing syngas over a first rector (10) containing Cu at a first temperature effective for the reaction of CO.sub.2 within the syngas with the Cu to form copper oxide and CO. The temperature of the syngas is then reduces to a second temperature effective for the for the reaction of hydrogen within the syngas with copper oxide to form Cu and H.sub.2O. The syngas is then passed over a second rector (12) containing copper oxide so that the H.sub.2 within the syngas reacts with the copper oxide.

Invention presents a method of increasing the CO to H.sub.2 ratio of syngas. The method comprises passing syngas over a first rector (10) containing Cu at a first temperature effective for the reaction of CO.sub.2 within the syngas with the Cu to form copper oxide and CO. The temperature of the syngas is then reduces to a second temperature effective for the for the reaction of hydrogen within the syngas with copper oxide to form Cu and H.sub.2O. The syngas is then passed over a second rector (12) containing copper oxide so that the H.sub.2 within the syngas reacts with the copper oxide.

A reactor for carrying out an endothermic reaction, in particular a high-temperature reaction, in which a product gas is obtained from a feed gas, wherein: the reactor surrounds a reactor interior; the reactor is configured to provide a reactor bed in a reaction zone of the reactor interior, which reactor bed comprises a large number of solid material particles; the reactor is also configured to guide the feed gas into the reaction zone; in order to heat the feed gas, the reactor is designed to heat the solid material particles in the reaction zone such that, by transferring heat from the solid material particles to the feed gas, the feed gas in the reaction zone can be heated to a reaction temperature in order to participate as a starting product in the endothermic reaction for producing the product gas.