Drying Process Analysis of Three-stage Multi-loop Paper Mill Sludge Drying Equipment

Since the launch of the three-stage multi-loop paper mill sludge drying equipment in the drying market, it has become a new choice for more and more paper-making enterprises.In fact, the difficulty in drying paper mill sludge mainly lies in two aspects:First, paper mill sludge has a large output, which requires equipment with fast drying speed and large processing capacity to meet the drying requirements;Second, the sludge has a high moisture content with the characteristics of high moisture and high viscosity, which brings great challenges to ordinary dryers.So how does this equipment solve these problems? Next, the editor from ZJN Drying System Co., Ltd. will introduce in detail how it dries paper mill sludge.

I. Three-stage Multi-loop Drying Technology

To ensure the drying efficiency of paper mill sludge, the large-scale paper mill sludge drying equipment produced by ZJN adopts a number of core patented technologies. After the sludge enters the dryer cylinder, the drying process is divided into three stages:

Stage 1

Wet materials are fed into the drying chamber along with hot air. The built-in rotary rake crushing device quickly disperses and breaks up the wet materials. At the same time, the material lifting system continuously lifts and scatters the materials, increasing the contact area between the materials and the hot air. After the moisture is evaporated, the sludge turns into a loose granular state and enters the next drying stage.

Stage 2

The hot air flows in the opposite direction to the materials, which improves the turbulence degree, fully absorbs the heat energy and reduces heat loss. Through counter-current drying, the internal moisture in the sludge is evaporated, achieving an ideal drying state.

Stage 3

In this stage, the materials travel in a multi-loop path. Dry materials are discharged from the drum quickly, while wet materials take two steps back and one step forward, and are discharged from the cylinder only after sufficient drying.

II. Drying Solution for High-moisture and High-viscosity Materials

The three-stage multi-loop paper mill sludge drying equipment adopts the method of direct contact between high-temperature hot air and the dispersed sludge, which enhances heat and mass transfer and improves drying efficiency.Through multi-layer drying, the internal water and cellular water in the sludge are completely evaporated. In addition, after entering the drying chamber, the sludge keeps moving at high speed under the action of the material lifting system and presents a fluidized boiling state, which effectively prevents the high-moisture and high-viscosity sludge from adhesion and agglomeration due to loss of fluidity.