Boilers fired by: (Bio)gas, Refinery gas, Oil, Biomass and Coal
Industrial heat is distributed using steam or hot water as energy carrier. The conversion of primary fuels takes place in a (steam) boiler via a combustion process. The exit temperature of the flue gas is proportional to the amount of heat lost and the loss of efficiency of the combustion process. Frequently, over 5% of the fuel is lost via hot flue gas.
Preheating combustion air with hot flue gas is a simple way to improve the boiler efficiency in a cost effective way. For corrosive flue gas the HeatMatrix polymer air preheater enables heat recovery over a large temperature range and prevents high maintenance cost as result of corrosion problems.
Metal air preheaters are designed for a minimum flue gas exit temperature of approximately 160 °C in order to prevent corrosion and subsequent high maintenance cost. The HeatMatrix polymer air preheater is a new generation air preheater that enables heat recovery beyond the acid dew point. For flue gas temperatures above 200 °C a combination between a metal and a polymer air preheater combines the best of both worlds
This hybrid design has the following advantages:
- Increased heat recovery over a wide temperature range
- The polymer air preheater protects the metal air preheater against low air temperatures that lead to cold spot corrosion problems
- The metal air preheater protects the polymer air preheater against high temperatures
See also the following links to:
A case study for Industrial Furnaces
Ovens are applied in many different industries and are heavy energy consumers. In the ceramic industry, for example, the hot off-gas contains corrosive components, which prevents the application of metal exchangers to improve energy efficiency. The HeatMatrix plastic heat exchangers are resistant to concentrated sulphuric acid and enable waste heat recovery from these corrosive and fouling off-gas streams. For flue gas temperatures above 200 °C a combination between a metal and a polymer air preheater combines the best of both worlds (see hybrid exchanger). The recovered waste heat can be used for preheating of combustion air or cold fluids.
Dryer applications are heavy energy consumers in the food and non-food industry. Up to 20% of the total energy consumed can be recovered when heat from the hot exhaust stream is transferred to the cold air inlet stream.
HeatMatrix offers a simple light weight compact heat exchanger for direct heat integration between hot off-gas and cold drying air. Its counter current flow characteristic and in-situ cleaning system provide the highest efficiency.
Indirect fired air heaters
Indirect fired air heaters offer an additional opportunity to improve overall energy efficiency. Especially in the case of oil fired air heaters a significant amount of waste heat can be recovered from corrosive flue gas by preheating cold process air or combustion air.
During chemical processing, corrosive off-gas can be generated. This corrosive off-gas is often treated in a dedicated incinerator (RTO) or co-fired in an existing steam boiler. Waste heat from corrosive flue gas can be used to preheat the cold off-gas or any other available outlet without acid dew point related corrosion problems.
CHP (COMBINED HEAT POWER)
Waste from wastewater treatment facilities is often used to produce biogas, which is subsequently used in CHP-units (biogas fired engines). High temperature heat from the CHP flue gas is already reused within the wastewater treatment facility for heating, waste drying or exported to a city-heating grid. The low temperature part of the CHP flue gas can also be reused when a HeatMatrix corrosive resistant exchanger is applied. The thermal efficiency of a CHP-unit is increased by up to 15% when the remaining flue gas waste heat below 180 °C is recovered. See also gas to liquid exchanger for further information.