## 3 Optimal Design of Pulse Dust Collection System  
### Concept Design  
The pulse dust collection system used is composed of four parts in this research, as shown in Figure 1. The first part is a bluer motor with a rotation speed of 3500 \(RPM\), which is provided to the dust collector to generate a static pressure of about 1900 mmAq and a flow rate of \(Q=78\)\(CMM\) to extract the dust in the system. The second part is the filter, which is composed of N = 9 filter groups, and each group is composed of two filters in series. The size of a filter element with fold type is outer diameter \(D_{i}=9.5^{\prime\prime}\), inner diameter \(D_{i}=9.5^{\prime\prime}\), length \(L=26^{\prime\prime}\), and fold number \(N_{fold}=152\), and the theoretical filter area is \(A_{t}=110^{\prime\prime}\left(10.219\ \mathrm{m}^{2}\right)\), as shown in Figure 1. The filter is made of polyester fiber spunbond as the base material, and its fiber diameter is about \(15\sim 21\ \mathrm{\SIUnitSymbolMicro m}\). A layer of PTFE film, of which the diameter is \(1\sim 0.2\ \mathrm{\SIUnitSymbolMicro m}\) and the thickness is about \(0.1\ \mathrm{mm}\), is plated on the outer layer of the spunbond. The fiber diameter of the material is about \(1\)-\(0.2\ \mathrm{\SIUnitSymbolMicro m}\) and the thickness is about \(0.1\ \mathrm{mm}\). The air permeability of the filter is \(k_{f}=200\ \mathrm{m}^{3}/(\mathrm{m}^{2}.\mathrm{Pa}\cdot\mathrm{hr})\). When the filter is aging, the dust will block it and cause the pressure drop to rise. When the static pressure difference between the inner and outer sides of the filter reaches \(150\ \mathrm{mmAq}\), the set of filters needs to be replaced. The third part is the pulse-jet cleaning system. When the outside of the filter is blocked by dust, the pulse timing controller of the backwashing unit will release pulse-jet air from the corresponding diaphragm valve to shake off the dust and discharge it into the funnel. The compressed air used in this study is \(P_{clear}=6.5-7\ \mathrm{kg}/\mathrm{cm}^{2}\), flow \(Q_{clear}=30\ \mathrm{L}/\mathrm{min}\), and the pulse timing controller provides a set of operating parameters such as pulse interval time (\(T_{w}\)) and pulse time (\(T_{p}\)). At each setting time, one filter element of the dust collector is always being cleaned, and the other filters maintain normal filtration operations. The orders of cleaning are top to bottom and left to right, as shown in Figure 2. In this study, the adjustable range of pulse interval time is \(T_{w}=5\sim 30\) s, and pulse time is \(T_{p}=0.1\sim 0.3\) s. The fourth part is a dust collection and a dust discharge. The dust collection is a funnel-shaped dust storage device. It is usually designed with a slope of \(60^{\circ}\) in the inside of the funnel, so that dust can fall freely to the bottom of the funnel from above. There is an ash discharge valve at the bottom of the funnel to isolate the atmosphere to maintain the static pressure of the system and to prevent the discharged dust from being sucked into the funnel again. The ash discharge action in this is that when the filter is backwashed for two rounds, the upper ash discharge valve opens and closes once to leak the dust to the temporary storage area. About 10 s later, the lower ash discharge leaks the dust to the storage bucket.