Pulp Process / Chemical

Wood chips are fed into a digester to which chemicals have been added. The woodchips are then ‘cooked’ with heat and pressure in sodium hydroxide (caustic soda) and sodium sulfide to remove lignin. This process is energy efficient as most by-products can be used to fire the pulp mill power plant.

Chemical pulping produces lower fiber yield than mechanical pulping, typically 50-60%, but the product is strong, can be bleached white, and resists yellowing.

PMC-STS, Inc. transmitters with remote flush-mount sensor are ideal to measure the pressure drop across the digester. This gives an indication of when the digester becomes plugged. The Remote Electronics Option handles high heat and vibration associated with digesters and the ceramic sensing diaphragm resists abrasion from the coarse stock and aggressive chemical attack.

In addition, PMC-STS, Inc. flush-mount standard and miniature diaphragm transmitters are used to measure water/chemical and stock levels.