Heat Module with ORC by SÜLZLE KOPF SynGas

SynGas Heat Module + ORC

The SynGas Heat Module with ORC offers all the advantages of the SynGas Heat Module with the added benefit of power generation. The so-called Organic Rankine Cycle drives a small turbine with generator for power generation from the waste heat from the synthesis gas combustion. Although the amount of electricity produced is considerably lower than with the SynGas CHP module, there is also much more heat left to dry the sludge.

Depending on the quality of the sludge, the entire drying and gasification system can still remain thermally self-sufficient or only slightly dependent on additional heat. The electricity generated covers the gasification’s own consumption completely and additionally about half of the power required to operate the dryer.

Advantages SynGas Heat Module + ORC

  • Simple, robust process
  • power generation to meet the gasification’s own requirements + approx. half of the drying process
  • Gasification + sludge drying almost or completely self-contained
  • Moderate specific investment costs

Process description: Heat Module – wet flue gas treatment – with ORC

Thermal utilization

From the silo, sewage sludge with a dry content of 85% – 95% (1) is conveyed together with limestone (2) into the fluidized bed gasifier (3). The added limestone binds sulphur in the first desulphurization stage. The high gasification temperature of 850 °C completely destroys all toxic substances in the sewage sludge and removes heavy metals such as mercury or cadmium from the valuable sewage sludge ash. It ensures that the vital phosphorus in the ash granulate can be made directly available for use e.g. as fertilizer. The almost carbon-free ash granulate (4) is removed from the process via a sluice and collected.

Synthesis gas cleaning and cooling

The synthesis gas produced in the fluidized bed gasifier is coarsely de-dusted in a cyclone (5) before the sensible heat of the synthesis gas is used in a heat exchanger (6) to preheat the combustion air. The cooled synthesis gas is cleaned further in a fine filter (7).

SynGas Heat Module wet gas cleaning with ORC

Combustion of the synthesis gas and heat recovery

The cooled and de-dusted synthesis gas is burnt in a combustion chamber (8). The heat generated during combustion is provided for heating thermal oil by means of heat exchangers (10). In another heat exchanger (11), an organic working medium is evaporated for use in an ORC-turbine (12). The condensation heat of the working medium is used recuperatively for preheating (13) and for decoupling low-temperature heat (14). This variant is used when other energy is available for sludge drying on site.

Flue gas cleaning according to the 17th German Federal Pollution Control Ordinance

The combustion chamber is equipped with a urea injection (9). The urea serves to reduce nitrogen oxide emissions to the limit values specified in accordance with 17th BImSchV. In a compact flue gas cleaning plant, environmental pollutants originating in the sewage sludge and remaining in the flue gas after synthesis gas combustion (among others as oxidised products) are removed e.g. Sulphur oxides and heavy metals.

First, an adsorbent (15) is entrained in the flue gas to incorporate heavy metals, which are subsequently removed from the process at the fine filter (16). The further treatment of the flue gas for cooling and reduction of the sulphur compounds takes place in a quencher (17) and an alkaline scrubber (18). After pre-treatment, the wastewater is discharged to the wastewater treatment plant.

Process description: Heat Module – dry flue gas cleaning – with ORC

Thermal utilization

From the silo, sewage sludge with a dry content of 85% – 95% (1) is conveyed together with limestone (2) into the fluidized bed gasifier (3). The added limestone binds sulphur in the first desulphurization stage. The high gasification temperature of 850 °C completely destroys all toxic substances in the sewage sludge and removes heavy metals such as mercury or cadmium from the valuable sewage sludge ash. It ensures that the vital phosphorus in the ash granulate can be made directly available for use e.g. as fertilizer. The almost carbon-free ash granulate (4) is removed from the process via a sluice and collected.

Synthesis gas cleaning and cooling

The synthesis gas produced in the fluidized bed gasifier is coarsely de-dusted in a cyclone (5) before the sensible heat of the synthesis gas is used in a heat exchanger (6) to preheat the combustion air. The cooled synthesis gas is cleaned further in a fine filter (7).

Process description to SynGas heat module dry gas cleaning with ORC

Combustion of the synthesis gas and heat recovery

The cooled and de-dusted synthesis gas is burnt in a combustion chamber (8). The heat generated during combustion is provided for heating thermal oil by means of heat exchangers (10). In another heat exchanger (11), an organic working medium is evaporated for use in an ORC-turbine (12). The condensation heat of the working medium is used recuperatively for preheating (13) and for decoupling low-temperature heat (14). This variant is used when other energy sources are available for sludge drying on site.

Flue gas cleaning according to the 17th German Federal Pollution Control Ordinance

The combustion chamber is equipped with urea injection (9). The urea serves to reduce nitrogen oxide emissions to the limit values specified in the 17th BImSchV (17th German Federal Pollution Control Ordinance).

In a compact flue gas cleaning plant, environmental pollutants originating in the sewage sludge and remaining in the flue gas after synthesis gas combustion (among others as oxidised products) are removed. An adsorbent (15) is entrained in the flue gas to incorporate heavy metals and sulphur oxides, which are removed from the process at the fine filter (16).