Trichlorosilane differential pressure coupling rectification process and dynamic control scheme

Abstract

The invention belongs to the field of purification in the chemical industry, and relates to a trichlorosilane differential pressure coupling rectification process and a dynamic control scheme. According to the process, the equipment comprises a flow controller used for controlling the feeding flow rate; a pressure controller used for controlling the tower pressure of a rectifying tower; a liquid level controller used for controlling the liquid levels of a tower top reflux tank and the tower kettle; a temperature controller used for adjusting the tower temperature of the rectifying tower; and a proportional controller used for fixing the ratio of the reflux quantity of a low-pressure tower to the feed flow, the ratio of the thermal load of a reboiler of a high-pressure tower to the feed flow and the ratio of the reflux quantity of the high-pressure tower to the tower top recovery quantity. According to the invention, heat integration is achieved in the technological process, and energy consumption is greatly reduced; the dynamic control scheme can stably control the feeding flow disturbance within 10% and the feeding impurity disturbance within 25%, and the purity of the trichlorosilane product obtained through separation is 99.99% or above; and the method has relatively high robustness and stability.

Description

technical field

[0001] The invention belongs to the field of purification in the chemical industry, and specifically relates to a process method and a dynamic control scheme for trichlorosilane differential pressure coupled rectification, especially suitable for dynamic differential pressure coupled rectification processes with similar boiling points of mixtures and extremely high product purity. control. Background technique

[0002] As the basic material of photovoltaic industry and integrated circuit industry, polysilicon plays an important role in mobile communication, new energy vehicles and other industries. Trichlorosilane is an intermediate product of polysilicon produced by the improved Siemens method, and its purity is one of the factors affecting the quality of polysilicon. Most of the trichlorosilane refining process adopts multi-stage rectification technology, which consumes a lot of steam and electric energy due to the large number of rectification stages, lar...

Examples

Embodiment 1

[0041] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. The feed flow rate is changed from 40000kg / h to 44000kg / h, and the dynamic response curve is as follows figure 2 As shown in (solid line), the overshoot σ of the purity of dichlorodihydrosilane is 0.004, the adjustment time is τ_s is 2h, and the residual e(∞) is 0.0001; the overshoot σ of the purity of trichlorosilane is 0.000058, and the adjustment time τ_s is 4h, residual difference e (∞) is -0.000009; silicon tetrachloride purity overshoot σ is 0.0096, adjustment time is τ_s is 4h, residual difference e (∞) is -0.00427; the temperature of high pressure tower T2 exceeds The adjustment value σ is 16°C, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the control process can handle the disturbance of +10% feed flow rate well.

Embodiment 2

[0043] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. The feed flow rate is changed from 40000kg / h to 36000kg / h, and the dynamic response curve is as follows figure 2Shown in (dotted line), dichlorodihydrosilane purity overshoot σ is-0.0127, the adjustment time is τ_s is 2h, residual difference e (∞) is-0.00012; trichlorosilane purity overshoot σ is-0.00019, The adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.000006; the overshoot of silicon tetrachloride purity σ is -0.0542, the adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.003; the temperature of the high-pressure tower T2 The overshoot σ is -15℃, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the control process can handle the disturbance of -10% feed flow rate well.

Embodiment 3

[0045] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. Feed composition becomes dichlorodihydrosilane 5% by dichlorodihydrosilane 4%, trichlorosilane 92%, silicon tetrachloride 4%, trichlorosilane 90%, silicon tetrachloride 5%, other The dynamic response curve is as image 3 Shown in (solid line), dichlorodihydrosilane purity overshoot σ is 0.00046, the adjustment time is τ_s is 2.5h, residual difference e (∞) is-0.00048; trichlorosilane purity overshoot σ is 0.000018, The adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.000014; the overshoot of silicon tetrachloride purity σ is 0.0021, the adjustment time is 3h for τ_s, and the residual difference e(∞) is -0.00056; the temperature of the high-pressure tower T2 The overshoot σ is 1.9℃, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the c...

technical field

[0001] The invention belongs to the field of purification in the chemical industry, and specifically relates to a process method and a dynamic control scheme for trichlorosilane differential pressure coupled rectification, especially suitable for dynamic differential pressure coupled rectification processes with similar boiling points of mixtures and extremely high product purity. control. Background technique

[0002] As the basic material of photovoltaic industry and integrated circuit industry, polysilicon plays an important role in mobile communication, new energy vehicles and other industries. Trichlorosilane is an intermediate product of polysilicon produced by the improved Siemens method, and its purity is one of the factors affecting the quality of polysilicon. Most of the trichlorosilane refining process adopts multi-stage rectification technology, which consumes a lot of steam and electric energy due to the large number of rectification stages, lar...

Examples

Embodiment 1

[0041] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. The feed flow rate is changed from 40000kg / h to 44000kg / h, and the dynamic response curve is as follows figure 2 As shown in (solid line), the overshoot σ of the purity of dichlorodihydrosilane is 0.004, the adjustment time is τ_s is 2h, and the residual e(∞) is 0.0001; the overshoot σ of the purity of trichlorosilane is 0.000058, and the adjustment time τ_s is 4h, residual difference e (∞) is -0.000009; silicon tetrachloride purity overshoot σ is 0.0096, adjustment time is τ_s is 4h, residual difference e (∞) is -0.00427; the temperature of high pressure tower T2 exceeds The adjustment value σ is 16°C, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the control process can handle the disturbance of +10% feed flow rate well.

Embodiment 2

[0043] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. The feed flow rate is changed from 40000kg / h to 36000kg / h, and the dynamic response curve is as follows figure 2Shown in (dotted line), dichlorodihydrosilane purity overshoot σ is-0.0127, the adjustment time is τ_s is 2h, residual difference e (∞) is-0.00012; trichlorosilane purity overshoot σ is-0.00019, The adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.000006; the overshoot of silicon tetrachloride purity σ is -0.0542, the adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.003; the temperature of the high-pressure tower T2 The overshoot σ is -15℃, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the control process can handle the disturbance of -10% feed flow rate well.

Embodiment 3

[0045] Each controller first carries out initialization operation, automatically inputs the set value, and reasonably determines the control range, and uses the closed-loop loop as the test method. Feed composition becomes dichlorodihydrosilane 5% by dichlorodihydrosilane 4%, trichlorosilane 92%, silicon tetrachloride 4%, trichlorosilane 90%, silicon tetrachloride 5%, other The dynamic response curve is as image 3 Shown in (solid line), dichlorodihydrosilane purity overshoot σ is 0.00046, the adjustment time is τ_s is 2.5h, residual difference e (∞) is-0.00048; trichlorosilane purity overshoot σ is 0.000018, The adjustment time is 4h for τ_s, and the residual difference e(∞) is 0.000014; the overshoot of silicon tetrachloride purity σ is 0.0021, the adjustment time is 3h for τ_s, and the residual difference e(∞) is -0.00056; the temperature of the high-pressure tower T2 The overshoot σ is 1.9℃, the adjustment time is τ_s is 4h, and the residual e(∞) is 0; it shows that the c...

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