High-pressure gravimetric feeder
The Stock® HPG (High Pressure Gravimetric) feeder is the heart of the Stock® feeder line. This model was researched, developed, designed, tested and manufactured by Stock®, specifically for the Utility and Industrial Power Industry.
The HPG series is designed for pulverized coal fired boilers that require feeders to withstand explosion pressures as high as 50 PSI (3.5 bar) in accordance with NFPA 85, and provide maximum safety and accurate coal feeding. This feeder has a typical conveying length of 7’ (2134mm) and can be designed as a drop in replacement. Stock® HPG feeders maintain accuracy within ± ¼ of 1 percent of the total coal flow.
The HPG offers reliable coal flow to the pulverizer under a wide range of coal conditions. The known coal mass flow rate will allow more accurate control of excess air. This will minimize NOx formation in stack gases. Less stratification of excess air between burners and better pressure and heat control result from the equal delivery of coal to each pulverizer in direct relation to the firing rate demand. Optimum air/fuel ratios are achieved when changing loads. Coal and air are kept in proportion by the boiler control system and can be controlled. Coal leaving the pulverizer can be maintained relatively constant, ensuring proper distribution at the burner.
Standard inlet widths are 24” (610mm) and 36” (914mm). Inlet shapes can be round or rectangular with length to width ratios up to 3:1. Feed rates up to 100 tons per hour are standard with higher capacities available.
Summary of Benefits
- Fuel savings through improved boiler efficiency.
- Ability to improve combustion efficiency/loss on ignition.
- Ability to improve pressure and superheat control.
- Less slagging, fouling, and corrosion.
- Ability to improve stability and response of combustion controls.
- Less NOX through better control of excess air.
- Reduced Operations & Maintenance costs.