About Us

Envio Energi's patented combustion technology allows you to burn all types of bio-fuel. Each combustion chamber is essentially a predry-gasification-combustion chamber which is connected to a boiler and is designed for either moist fuels (TRF) or drier fuels (TRT). Both types are equipped with a unique hydraulic and individually controlled grate axes that control the combustion process in the furnace. This patented grate system in combination with computerized control of the combustion process assures efficient and complete combustion and eliminates any chance of ash chute fires.

The combustion furnace is built with a powerful outer iron casing and interior masonary lining. The outer casing is double walled with an air gap between the inner and the outer walls. Secondary and tertiary air circulates through this air gap effectively both cooling the combustor casing and preheating the combustion air.

è Individually controlled primary air for each primary air zone

è Modulating secondary air
è Controlled flue gas recirculation
è Automatic ash removal

Fuel Feed Chute
The fuel feed chute is equipped with hydraulically driven pushers that feed the pre-combustion chamber with the right amount of fuel to meet the plant load. The feeding chute of the combustion furnace is equipped with a level control that starts and stops the fuel feeding system. A safety damper close the feeding chute and a water sprinkler system is actuated in case of backfire. The three hydraulically operated stokers, each individually acting, secure a balanced and smooth fuel bed feeding into the furnace.

The movable grid system consists of both moving and firm grids assembled in a random design to make a smooth bed in the furnace and a controlled combustion. The feeding speed on fuel and ash is controlled by a PLC system. Every step of the grate can individually be controlled.

The grid system is divided in stages. Every second grid is moving and every other is stationary. Each movable grid has a firm grid the stage above and below. In this way the whole grid works in zigzag pattern producing a burning bed which is very even in thickness and maximizing combustion.

Hydraulic Driven Grates
Envio Energi's patented combustion furnace is equipped with hydraulically operated grate shafts, which allows individual adjustments to control the burning process. The grids rest on a water cooled grid support, covered with wear plates.

Boiler
Envio Energi utilizes two types of boilers. Which is suitable depends on the pressure and the temperature required and if steam or hot water shall be produced. For production of hot water a fire tube boiler is used. Fire tube boilers are typically limited to 16 bar design pressure at 204º C water temperature.

If higher pressure and temperature steam is required a water tube boiler is used. Pressures well above 50 bar and temperatures of around 450º-500ºC are commonly required for cogeneration (CHP) plants.

Boilers are delivered with an automatic soot cleaning system. Water tube boilers are equipped with steam jet blowers.

The combustion furnace is connected to a hot water boiler or a steam-boiler via a brick walled gas channel. A portion of the flue gases are circulated back to the pre-furnace via a flue gas recirculation fan. The flue gases pass through the boiler to a multi-cyclone or an electrostatic precipitator.

The prefered method to clean particulates from the flue gases is to install a multi-cyclone. The multi-cyclone can clean down to 150-250 mg/Nm³ depending on the moisture in the flue gases.

Alternative cleaning methods may employ bag filters and/or electrostatic precipitators. Bag filters can clean the flue gases more completely than an electro-filter, but bag filters typically have higher maintenance costs and a higher pressure drop which requires a larger flue gas fan and results in slightly higher energy costs.