PRODUCT DESCRIPTION P ECKROHR POWER BOILERS, SINGLE GRATE FIRED for producing steam from SOLID FUEL

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1 PRODUCT DESCRIPTION P ECKROHR POWER BOILERS, SINGLE GRATE FIRED for producing steam from SOLID FUEL DGA ECKROHR BIOMASS BOILER WITH VEE GRATE This boiler is rated for 45 tn/h steam at 65 barg pressure and 490 C Main features of the DGA Eckrohr boiler are :- The boiler is manufactured under license from ERK Eckrohrkessel GmbH of Berlin Germany, for many, the world s premier boiler designer. The ERK license family have built in excess of 6000 boilers since ERK was formed some 60 years ago. Most boilers are installed in Europe. The boiler is suited to both Biomass and RDF (Refuse Derived Fuel) combustion. The 3 pass design is a very versatile design and suitable for all fuels. The Vee Grate was designed specifically for the ERK boiler, allowing the boiler to be compact, and to use all the advantages of a staged combustion firing, ie high efficiency, low Nox and low CO with low excess air with a wide range of fuels see P3 ERK designed boilers can be factory assembled, and then knocked down for transport to site for final erection. This reduces expensive site time The advantages listed on page 2 explain why the ERK boiler are so favored by boiler operators world wide The boilers are generally built to ASME code and can be completed anywhere the facilities exist to the meet this standard. The Single Grate range extends from 10 tn/h to 60 tn/h boilers with high pressure and temperature, can generate from 1 to 12 MWe from a suitable turbine generator. DGA Co Ltd, Tel. No: ; E mail : dga@dga.co.th;

2 ADVANTAGES OF DGA ECKROHR BOILER Quick Start Up At start up water circulation starts very quickly as the distances from downcomers to the heated risers on the water side are consistent and short the short distances mean that all water tubes reach saturation temperature quickly, so potentially dangerous thermal stresses in the boiler are avoided There is no bottom drum containing large quantity of water which must be heated during start up on bi-drum designs The steam drums is isolated from flue gases so thermal stress and corrosion in this area is avoided. Bidrum boilers are generally swept by the flue gases. The tube connections to the drum on an Eckrohr boiler are few and of large bore. The design allows for the loss of metal at each penetration leading to considerably thinner drum shells than bidrum boilers. Bidrum boilers have many small tube penetrations so it is necessary to design the drums on their ligament efficiency. This can double the metal thickness. Thin drum walls reduce thermal stress during the light up cycle. Even and thin metal thickness of the drum means that drum distortion during light up is minimal Downcomers are large and uncooled. Steam bubbles forming at pressure fluctuations and high load change can not endanger water circulation. Self Supporting Construction Thermal expansion is from bottom to top. This is an advantage with grate firing because the expansion difference between boiler and grate is minimal. With top hung designs sealing between grate and boiler can be difficulty. Low Pressure variations at Load Changes Quick Load variations are possible without significant changes of steam pressure Water level in the drum remains calm compared to other boiler designs High Steam Purity Steam separation system takes place in the drum and external to the drum in the large bore overflow pipes and steam headers. High steam purity can be achieved even with poor water quality Economical space requirements The design using external downcomers allows heat exchangers to be located some distance from the drum allowing compact arrangements to be designed Compact designs have been developed which allows completed boilers to be delivered to site in one piece. References The ERK boiler has 6000 references around the world firing all fuels with many Biomass and many Waste Fired units mainly in Europe. The reference plants have been built by other Eckrohrkessel licensees and all information and experience on these plants transfer to DGA via the ERK licence system. DGA/BIB/Sbang have a number of ERK boiler references which have been constructed over the past 15 years, most recently The 60 tn/h boiler for APK at Hat Yai The 45 tn/h boiler at Natural Palm The 45 tn/h boiler at Clover Prae.(in construction) The 30 tn/h boiler at CBE Project Pitsonuluk (In construction)

3 SUITABLE FUELS FOR THE DGA ECKROHR BOILER The following Biomass fuels are suitable for firing on a Vee grate in a DGA Eckrohr Boiler Palm Wastes, fibre, shell, trunk, EFB and similar fuels such as coconut wastes Rubber Wood slab and stump Rice Husk Bagasse Casava Rhizome Sugar Trash Giant King Grass and similar grasses From Eucalypus Tree Wood chip Fresh bark Bituminous Coal The following Waste Fuels are suitable for firing on a Vee Grate in a DGA Eckrohr Boiler Refuse Derived Fuel (RDF) from a suitable treatment system Reject biomass from RDF plant after treatment typically by the Bio-Dry system to reduce moisture content to c 30% Combustion Requirements Size Constraints The fuel must be sized in accordance with DGA Product Sheet Fuel Sizing for DGA Grates LCV constraints DGA will advise the ability of the DGA Eckrohr boiler to handle any waste or Biomass fuel from an accurate ultimate analysis of the fuel, inclusive annual variations of Moisture Content. From this DGA calculate a real LCV which must meet the following requirements :- LCV must be better than 4500 kj/kg if superheat steam required The Moisture content of biomass must be lower than 55% The boiler will be fitted with a flue gas air heater if high air preheat is necessary due to low LCV. This can be as high as 300 C on the standard grate allowing wetter fuel to be burned. Emission Constraints The emissions must meet the Emission Criteria published by the Government. DGA target the EU WID limits to ensure a comfortable compliance. Mainly relevant to RDF fired plants, if the Ultimate Analysis show that any of the following are high, then an upgraded gas scrubbing system is required Sulphur and Chlorine contents Heavy Metals Dioxin and Furans

4 TYPICAL ARRANGEMENT OF A DGA ECKROHR BOILER FIRED BY A VEE GRATE / A 30 tn/h DGA Eckrohr Boiler in construction for SBANG Corporation for their Project at CBE Project at Pitsonuluk. The Diagram shows features of the boiler Including the withdrawable Vee Grate, the pendant superheater in the 2 nd pass, and the overall compact design of the ERK boiler with high Temperature air heater and economiser With more than 6000 boilers installed around the world users can take reassurance that they have made the right choice of boiler. The single drum design with DGA s Vee Grate is a winning combination.

5 PRODUCT DESCRIPTION P ADVANTAGES OF THE VEE GRATE DGA VEE (Vibrating Combustion) Grates have been developed as a grate capable of firing all biomass solid fuels, from palm oil waste through wet bark and wood wastes to clean wood chip and even bituminous coal Fuel Spreading Fuel is spread through the flames already established on the grate to cause ignition of the incoming fuel. The ignited fuel lands on the grate adding to the established fuel bed, and the action of the grate moves the whole fuel bed towards the front of the grate where the ash discharge conveyor is located. Gentle Wear The vibrating action of the grate moves the fuel bed gently down the grate with little wear to the grate surface. The vibrating causes the fuel to be spread to an even depth on the grate and together with the air drafting dislodges the ash particles from the live fuel. Denser ash falls as bottom ash to the ash discharge conveyor. High Air Preheat Because there are no moving or rotating parts in the combustion airbox high levels of air preheat are available to allow combustion of even very wet biomass fuel. Handles sticky fuels The combustion deck of the grate is water cooled in order to stop fuels from sticking to the grate during combustion and also to retain the physical strength of the construction material. Low Vibrated mass Attention has been given to reducing the overall vibrated mass so the grate is built around a space frame in light clad material. In order to reduce the impact of the vibration. Good Combustion Combustion of solid fuel is the major part of the design of this grate so it has been designed for good distribution of combustion air, injected at optimum pressure for good air:solid mixing on the grate.. High Thermal Rating Up to 2 MW/m 2 is available for most biomass fuels. This reduces to ~ I.2 MW/m2 with low calorific value low reactivity coals High Efficiency The main feature of the grate is that it forms the heart of a modern high efficiency firing system, that is able to burn a variety of biomass fuels, sized for < 80 mm particles with good fuel burn out ie low carbon in ash, even when fired at low excess air. Standard grates are available to operate at 45% excess air and with staged air combustion this can reduce to ~ 30 % excess air.

6 PRODUCT DESCRIPTION P ADVANTAGES OF THE VEE GRATE (cont) This picture was shot through the peephole of a furnace whilst the boiler was firing at high load on Palm Empty Fruit Bunch The stack was clear. Other Equipment Ancillary Equipment that may be supplied with the Vee Grate are : Spreader Stokers for Biomass. These are also used for waste materials such as RDF. Mechanical Spreaders for coal and lump biomass Variable screw feeders for biomass and or solid fuel Wet ash discharge conveyors Vibrating sequence Control The range of grates available currently spans from 7 MW thermal to 175 MW thermal. This is the equivalent of firing steam boilers rated from 10 to 200 tn/h of steam. More than 30 Vee Grates are operating primarily on Mackenzie Boilers for use in their Palm Oil Boilers and latterly on boilers supplied by Bangkok Industrial Boilers of Thailand. The Vee grate has been installed on boilers through Malaysia, Indonesia and Thailand. Recent projects have been quoted in Africa and Cambodia. Vee Grates are supplied by :DGA Co Ltd 315/344 Soi Wat Po Man Sathupradit Rd, Yannawa Bangkok, Thailand Tel No. : Website : DGA Co Ltd, Tel. No: ; E mail : dga@dga.co.th;