A method of charging and/or discharging energy in reusable fuel workpieces or particles includes a solar furnace with counter-flowing workpieces and gas, to exchange heat therebetween, with the exiting gas and workpieces being at about ambient temperature. A further aspect employs a production plant including a reduction reactor configured to use excess electrical energy generated by renewable power generators to charge and/or discharge solid-state thermochemical fuel. Another aspect includes a fuel flow control valve using air pulses. An oxygen-deprived and reusable fuel, such as magnesium manganese oxide, or magnesium iron oxide, is also provided. In another aspect, an apparatus for producing a solid-state fuel includes a reduction reactor including a reactor chamber configured to receive concentrated solar energy, and a reactor tube having a recuperation zone, a reduction zone, and a quenching zone, wherein the reduction zone passes through the reactor chamber. A discharged solid-state fuel is configured to be fed down the reactor tube and a low-oxygen gas is configured to flow up the reactor tube.

A method of charging and/or discharging energy in reusable fuel workpieces or particles includes a solar furnace with counter-flowing workpieces and gas, to exchange heat therebetween, with the exiting gas and workpieces being at about ambient temperature. A further aspect employs a production plant including a reduction reactor configured to use excess electrical energy generated by renewable power generators to charge and/or discharge solid-state thermochemical fuel. Another aspect includes a fuel flow control valve using air pulses. An oxygen-deprived and reusable fuel, such as magnesium manganese oxide, or magnesium iron oxide, is also provided. In another aspect, an apparatus for producing a solid-state fuel includes a reduction reactor including a reactor chamber configured to receive concentrated solar energy, and a reactor tube having a recuperation zone, a reduction zone, and a quenching zone, wherein the reduction zone passes through the reactor chamber. A discharged solid-state fuel is configured to be fed down the reactor tube and a low-oxygen gas is configured to flow up the reactor tube.

An inactivation treatment apparatus includes a rotary kiln main body in which coal flows from an end side toward a tip side; a cooling tube arranged rotatably in conjunction with the rotary kiln main body and extends in the direction of the length of the rotary kiln main body, and in which cooling water can flow; and a treatment gas supply tube arranged rotatably in conjunction with the rotary kiln main body, and extends in the direction of the length of the rotary kiln main body, and can supply a treatment gas into the rotary kiln main body. In the apparatus, each of the cooling tube and the treatment gas supply tube is arranged to move past through a coal layer, which is a layer formed as the result of the sedimentation of the coal, in the rotary kiln main body when the rotary kiln main body rotates.

An inactivation treatment apparatus includes a rotary kiln main body in which coal flows from an end side toward a tip side; a cooling tube arranged rotatably in conjunction with the rotary kiln main body and extends in the direction of the length of the rotary kiln main body, and in which cooling water can flow; and a treatment gas supply tube arranged rotatably in conjunction with the rotary kiln main body, and extends in the direction of the length of the rotary kiln main body, and can supply a treatment gas into the rotary kiln main body. In the apparatus, each of the cooling tube and the treatment gas supply tube is arranged to move past through a coal layer, which is a layer formed as the result of the sedimentation of the coal, in the rotary kiln main body when the rotary kiln main body rotates.

A process for producing a modified coal from a coal of low-rank as a raw material includes dehydrating the coal, adding water to the dehydrated coal, agglomerating the water-added coal, and gradually oxidizing the agglomerated coal. In the water addition, an added amount of the water is regulated so that the water-added coal has a water content of 5% by mass or more and 20% by mass or less. In the oxidation, the agglomerated coal is held in an air at a temperature of 70? C. or more and 105? C. or less.

A process for producing a modified coal from a coal of low-rank as a raw material includes dehydrating the coal, adding water to the dehydrated coal, agglomerating the water-added coal, and gradually oxidizing the agglomerated coal. In the water addition, an added amount of the water is regulated so that the water-added coal has a water content of 5% by mass or more and 20% by mass or less. In the oxidation, the agglomerated coal is held in an air at a temperature of 70? C. or more and 105? C. or less.

A method for producing modified coal using coal of a low grade comprising: adding water for preventing any dust generation to the dewatered coal; an addition amount of the water is adjusted for a water content rate of the water-added coal to be 6% by mass or more to 16% by mass or less; agglomerating the water-added coal; slowly oxidizing the agglomerated coal; and crushing the oxidized coal.

A method for producing modified coal using coal of a low grade comprising: adding water for preventing any dust generation to the dewatered coal; an addition amount of the water is adjusted for a water content rate of the water-added coal to be 6% by mass or more to 16% by mass or less; agglomerating the water-added coal; slowly oxidizing the agglomerated coal; and crushing the oxidized coal.

An oil-coal co-hydrotreating processing includes the following steps: pulverized coal, vacuum residue and recycle oil are mixed to prepare coal slurry. After mixed with hydrogen, catalyst and additive, oil-coal slurry is preheated into a slurry bed reactor with high reacting pressure for thermal cracking and hydrogenation reaction. After reaction, all the products go into the hot high pressure separator for separation of solid from the bottom and gas from the top. The gas obtained goes into the fixed bed reactor for further hydrocracking or refining, and the distillate obtained enter the fractionating tower. The vacuum gas oil from the bottom of fractionating tower is taken as recycle oil piped to the oil-coal slurry mixing device as solvent.

An oil-coal co-hydrotreating processing includes the following steps: pulverized coal, vacuum residue and recycle oil are mixed to prepare coal slurry. After mixed with hydrogen, catalyst and additive, oil-coal slurry is preheated into a slurry bed reactor with high reacting pressure for thermal cracking and hydrogenation reaction. After reaction, all the products go into the hot high pressure separator for separation of solid from the bottom and gas from the top. The gas obtained goes into the fixed bed reactor for further hydrocracking or refining, and the distillate obtained enter the fractionating tower. The vacuum gas oil from the bottom of fractionating tower is taken as recycle oil piped to the oil-coal slurry mixing device as solvent.