Reformed gas waste heat boilers
BORSIG Process Heat Exchanger GmbH offers two different designs of the reformed gas waste heat boiler.
1. Reformed gas waste heat boilers with thin stiffened tube sheet design

We supply reformed gas waste heat boilers for gas inlet temperatures of up to 1,200°C and steam pressures of up to 160 bar (16,000 kPa). The reformed gas waste heat boilers for high-pressure steam are designed and manufactured with a specially developed and patented stiffened tube sheet systems. In this unique design the pressure load on the thin tube sheet caused by the high steam side pressure is transferred via the stiffener system into the shell. The tube sheets do not bend and remain flat in all operating conditions. Since the tube sheet is thin, very efficient cooling and low metal temperature is obtained. The tube to tube sheet weld is performed as a full penetration weld which excludes crevice corrosion and is state of the art for such applications.
As the tube to tube sheet weld is located on the water side of the tube sheet, its temperature during operation is close to the boiling temperature of the water.
If requested by the customer, the reformed gas waste heat boiler can be equipped with an internal gas-side bypass. This particular design, which has been developed and patented by BORSIG, allows to control the gas outlet temperature by means of the simple adjustment of just one valve which simultaneously influences the mass flow through the bundle tubes and also through the bypass tube.
The benefits of the tube sheet systems are for example no life time limitation due to operation or fatigue cycles, no limitation on tube length and the ability to install the waste heat boiler horizontally or vertically.
The reformed gas waste heat boiler can be designed with an internal gas side bypass on request. Our patented design allows the gas outlet temperature to be accurately controlled by adjusting only one valve, which simultaneously controls the mass flow through the bundle tubes as well as through the bypass tube.
2. Reformed gas waste heat boilers with thin flexible tube sheet design

We supply reformed gas waste heat boilers for gas inlet temperatures of up to 1,200°C also with thin, flexible tube sheet design.
The tubes act as stays between the tube sheets. Therefore the stresses in the tube to tube sheet weld are much higher compared to the stiffened tube sheet design. The tube sheets are thin and therefore have low surface temperatures. The tubes are connected to the tube sheet by a full penetration weld. No crevice corrosion can occur as there is no gap between tube and tube sheet.
The temperature of the tube welds in operation is close to the saturated steam temperature. They are located on the water side of the tube sheet and thus are well cooled.
The reform gas waste heat boiler can be designed with an internal gas side bypass on request. Our patented design allows the gas outlet temperature to be accurately controlled by adjusting only one valve, which simultaneously influences the mass flow through the bundle tubes and through the bypass tube.



