Oxycombustion process for producing energy wherein low ranking gaseous, liquid, solid, optionally solid melting hydrocarbon fractions are used as fuels, having a vanadium content in amounts by weight from 50 to 5,000 ppm or higher, and alkaline metals Ma in amounts from 20 to 10,000 ppm, wherein magnesium is added as oxide, or as a magnesium compound forming MgO in the combustion process, or mixtures thereof and a silico-aluminate wherein the molar ratio SiO.sub.2:Al.sub.2O.sub.3 ranges from 2:1 to 6:1; the combustor being refractored, isotherm or quasi-isotherm, flameless, working at temperatures in the range 1,250-1,450 C. and under pressurized conditions, wherein the oxidant being used in admixture with water or steam, the ratio by moles oxidant:(water/steam) being comprised between about 1:0.4 and about 1:3, or the oxidant is used in admixture with flue gases recycled from the flue gases outletting the energy recovery equipments, wherein the water/steam amount is higher than 30% by volume, optionally by adding water to the recycled flue gases, the molar ratio oxidant:(water/steam) in flue gases being comprised from about 1:0.4 to about 1:3; the hydrocarbon fraction being fed in admixture with water or steam, the amount of water/steam being at least 30% by weight with respect to the hydrocarbon fraction.

A CO.sub.2 recovery unit includes an absorber that reduces CO.sub.2 in flue gas (101) discharged from a combustion facility (50) by absorbing CO.sub.2 by an absorbent, a regenerator that heats the absorbent having absorbed CO.sub.2 to emit CO.sub.2, and regenerates and supplies the absorbent to the absorber, and a regenerating heater that uses steam (106) supplied from the combustion facility (50) for heating the absorbent in the regenerator and returns heated condensed water (106a) to the combustion facility (50). The CO.sub.2 recovery unit further includes a condensed water/flue gas heat exchanger (57) that heats the condensed water (106a) to be returned from the regenerating heater to the combustion facility (50) by heat-exchanging the condensed water (106a) with the flue gas (101) in a flue gas duct (51) in the combustion facility (50).

The gasifier operates to mix a start up heat source with crude syngas combustion for driving gasification of waste. Combustion flue gas can be maintained above 650 C. until reaching a quench to prevent formation of dioxins. Excess heat is liberated through a heat recovery unit. The gasifier can operate in a batch mode to process small batches of waste efficiently for small installations, such as ships, apartment buildings, hospitals and residences.

Preferred embodiments provide a system and method of generating steam comprising providing a continuous supply of coal, combusting the coal in a primary processing chamber in the presence of oxygen and water to provide a first product gas stream, recovering heat from the first product gas stream in a first heat recovery steam generator (HRSG) to produce a first steam output, processing the first product gas stream in a secondary processing chamber in the presence of oxygen and water to provide a second product gas stream substantially free of inorganic, organic and particulate contaminants, recovering heat from the second product gas stream in a second heat recovery steam generator (HRSG) to produce a second steam output, and combining the first steam output and the second steam output. In preferred embodiments, the combined steam output is used to drive a steam turbine. In certain preferred embodiments, the steam turbine is operatively coupled to an electric generator to produce electricity. In preferred embodiments, the system and method further comprises at least one of reducing the temperature of the second product gas stream, treating the second product gas stream by wet scrubbing, separating sulfur from the second product gas stream and collecting the sulfur with a baghouse, using a carbon dioxide recovery system, and discharging a treated gas stream substantially free of contaminants.

A plant for the treatment of materials, in particular waste materials and refuse, comprises a combustion reactor to which the material to be treated can be supplied. The combustion reactor has an input for a combustion supporter comprising oxygen and an output for the gases that are produced during the combustion of the materials inside the reactor and, in use, is substantially isothermic or quasi-isothermic at high or very high temperature, and without substantial oxygen deficit, in all of its parts. A portion of the combustion gases is recirculated and mixed with the combustion supporter to bring about a high degree of opacification thereof, which is increased by increasing the total pressure of the combustion chamber. The substances which cannot be gasified inside the reactor are immediately fused. The parameters of the gases at the output from the reactor are constantly measured by sensors with response-time characteristics of about 2 seconds.

The invention provides a burner apparatus comprising: a combustion chamber (8); a fuel dispenser (15, 16) arranged to direct a flow of fuel into the combustion chamber (8), the fuel dispenser (15, 16) being located at an upstream end of the combustion chamber and being connected or connectable to a fuel supply; an airflow modifier device (10), located at an upstream end of the combustion chamber, for controlling a primary air flow into the combustion chamber (8), the airflow modifier device (10) being configured to facilitate mixing of the air with the fuel to give a mixture for combustion; and one or more secondary air channels (24) for directing a cooling secondary air flow onto a stream of combustion products (e.g. flame) as the stream of combustion products emerges from a downstream end of the combustion chamber.

Also provided are a dryer apparatus comprising a burner apparatus as described herein and a method of drying aggregates using a burner apparatus as described herein.